Presentation to the 11^th Meeting of the PNT Advisory Board

The following is an abbreviated transcript of Don Jewell’s briefing to the PNT Advisory Board at its meeting on Tuesday, May 7. The slides from Jewell’s briefing and the other briefings to the board are available at pnt.gov under the heading 11th PNTAB meeting.

Good morning, everyone.

A special thanks to Jim Miller, Dr. James Schlesinger and Dr. Bradford Parkinson for inviting me to speak this morning on the future trends of PNT user equipment, particularly as it pertains to warfighters and first responders — certainly a subject I have been passionate about for only…oh, let’s say about 35 years.

Why GPS World?

Ever since the agenda for the PNT Advisory Board meeting appeared online, I have been receiving emails and phone calls asking why I was speaking not as one of the IDA (Institute for Defense Analysis) subject-matter experts on GPS but as the Contributing Editor for Defense for GPS World. Frankly, the answer is simple. Wearing the GPS World hat gives me the freedom to say what needs to be said today, whereas the IDA think tank attribution and publication rules, which are absolutely necessary for an FFRDC (Federally Funded Research and Development Center) to operate effectively and efficiently, would unduly restrict my comments.

Plus, for 21 years GPS World magazine has been the publisher of the definitive GPS user equipment survey for global users. It’s free for everyone to use, and it covers PNT receiver information from 55 global manufacturers with data on all aspects of 502 PNT receivers. And it is a great boon for me personally, as I only receive on average about 50+ emails or letters per month from users simply wanting to know what GPS/PNT receiver they should purchase. It is wonderful to be able to point them to the GPS World Receiver Survey.

Also wearing my GPS World hat, I can easily refer to the several thousand warfighter and first responder inputs we have received over the last 10 years — generally expressing what they would like to see in a GPS/PNT receiver or sometimes specifically the Perfect Handheld PNT Transceiver (PHPNTT), which I first wrote about six years ago (and most recently in December) in GPS World magazine.

Top 10 Warfighter – First Responder Requirements for the PHPNTT

Adhering strictly to the latest fad in government briefing formats, it is now time for me to BLUF, or give you the Bottom Line Up Front. However, being a journalist, I also have to hold something back for the end. So here are the top 10 PHPNTT requirements, in order of preference, as submitted over the last 10 years by thousands of warfighters and first responders:

• Mil-Spec rugged – solid state drive – no moving parts
• Friendly, intuitive, familiar interface – easy to use
• Multi-GNSS – All signals available – space and terrestrial
  • Wi-Fi, eLORAN, space/terrestrial augmentations, networks, communications
• Wireless, portable, seamlessly networkable
• SWAP friendly, long battery life, with solar charger
• Real-time 3D map data, NGA, Google, satellite imagery
• Not a stand-alone PNT device
  • Embedded in a computer with multiple communication capabilities – one must be secure
• Must be able to download, store and utilize new applications
• Software-defined and expandable
• Act as a sensor with automatic reporting

All these “user requirements” are closely related to what our warfighters and first responders don’t like about the current GPS MUE or Global Positioning System Military User Equipment. I state that specifically because, make no mistake about it, the current MUE is strictly GPS-based. However, the current MUE only receives two of the many signals available today on the GPS SVs, and certainly not any of the other numerous PNT (position, navigation and timing) signals also available, which of course is the crux of the issue for user equipment of the future.

Most of the top 10 requirements, and there were more than 50 requirements identifiable in all, are self-explanatory, and time does not permit me to cover them all in detail. But bear with me for a couple of quick explanations. Certainly the rugged requirement is readily understandable, and there are numerous manufacturers around the globe today that make excellent Mil-Spec rugged devices. However, the one I am most familiar with and have been extremely happy with are the rugged units from Trimble Navigation produced in Corvallis, Oregon. Trimble also happen to be a certified SAASM (Selective Availability and Anti-Spoofing Module) supplier as well.  More on those units later.

The second bullet concerns the human-machine interface on the current MUE, which is so poor that a Marine three-star wrote me a few years ago to say that in his opinion, “If anyone wants an example of how not to design an operational equipment interface then they should refer to the PLGR or DAGR. Both are consistently and sufficiently horrendous, in my opinion.”  I could not have said it better. The PLGR and DAGR use the gold standard for PNT as a signal, but the human-machine interface (HMI) is, in my opinion and in the opinion of thousands of warfighters, so antiquated and non-user friendly as to be almost unuseable. However, the units do work well and provide outstanding signals when embedded with other equipment. They just do not work well as a handheld device. The other items on the list we will cover as we proceed through the briefing.

GPS MUE Historical Perspective

I have been involved with GPS user equipment for the last 35 years, and this behemoth of a receiver was my first unforgettable encounter.

First GPS MUE receiver developed under government contract by Rockwell Collins, circa 1977.

Yes, this huge device is GPS user equipment. Can you imagine? It weighs more than 300 pounds, without the two operators, and was the very first workable GPS receiver produced for the U.S. military by Rockwell Collins, who has been producing GPS MUEs ever since. Which is an example of the prodigious acquisition issues that also need to be addressed, or corrected, if you will. Our antiquated acquisition practices are to blame for many of the failings in MUE equipment today. While I feel it is critical to mention this as a major contributing factor to the state of MUE today, it is also a story for another time.

Other than being the first GPS MUE, the significance of this huge receiver is that in my estimation it is the first and last time the U.S. military possessed a purpose-built military GPS receiver clearly superior to the products being produced by commercial and civil manufacturers for global users.

First Significant Usable and Transportable GPS Civilian Receiver

Fortunately, a good friend and colleague, both at IDA and ION (Institute of Navigation), Philip Ward, came to the rescue of all GPS users in 1981 when he delivered the TI 4100 NAVSTAR Navigator Multiplex Receiver.

TI 4100 NAVSTAR Navigator Multiplex Receiver designed by Phil Ward for Texas Instruments.

The TI 4100 was indeed the first commercially viable receiver that could be considered a transportable by anything other than an aircraft. To be historically correct, there were some backpack models that were very short-lived and not as significant as the TI 4100. The main unit and two antennas weighed approximately 50 pounds and showed promise in station wagons and helicopters. I can see a few folks in the audience smiling, so I will reiterate that the TI 4100 was a significant milestone, both in SWAP (size, weight and power), accuracy and TTFF (time to first fix). TTFF was 15-20 minutes in search mode, however; after the four SVs were located and the unit was initialized, it could consistently present a fix location in just a couple of minutes. Plus, the TI 4100 was immune from most jamming signals of the day — an impressive receiver and accomplishment for 1981.

Evolution of Commercial GPS/PNT UE

Fast-forward several years and the following picture presents a view of how quickly GPS UE developed.

Trimble units from the mid 1980s until today.

The first unit on the right in the above photo is a Trimble unit that was about the same size as the TI 4100, but considerably more capable. As you follow the units around counter clockwise, you will see that they decrease in size and weight, but what you can’t see is that they also increase incredibly where acquisition and processing speed (TTFF), accuracy and capability are concerned. Note also that you start to see stand-alone units that appear to be antennas with separate handheld display units. This is a feature the commercial manufacturers incorporated over 20 years ago, and in some respects a feature the MUE manufacturers and services are just now considering.

The defacto Garmin standby device.

Note also the Garmin GPS wrist receiver (right), which until 2005 was the most prevalent civil receiver in both of the wartime AORs (Area of Responsibility). Compare this Garmin wrist unit to the 300-pound Rockwell Collins unit I first showed you and consider that where SWAP and performance are concerned, the wrist unit is hundreds of times more capable and portable.

Current MUE – Program of Record and the Future

The pictures below depict the current MUE – Program of Record equipment, again both manufactured by, you guessed it, Rockwell Collins. First is the PLGR or the Precision Lightweight GPS Receiver. Second is the DAGR or Defense Advanced GPS Receiver. The third unit, known simply as the “Puck,” is what the U.S. Army would like to field in the next couple of years along with that separate display unit I spoke of earlier. Starting to sound very commercial, right? By the way, the Puck measures only 2 x 2 x 1/2 inches and weighs just a few ounces.

Rockwell- Collins PLGR.

Rockwell Collins DAGR.

Army’s Future PUCK.

Between the PLGR, which was decertified by the Marine Corps in 2010, and the DAGR, there are approximately 500,000 of these MUE devices fielded today, and yet almost none of them are utilized as handhelds. Our research shows that indeed only 1 in 40 is used as a true stand-alone handheld. Most DAGRs are primarily used to interface with legacy communications equipment, primarily U.S. Army, that calls for fire support, read ordnance, and all the others are either stored or embedded with other equipment, which means the “horrendous user interface,” a common warfighter description, is not a major issue. The bottom line is the DAGR is very good at what it does, it is just that what it does (warfighter quote) “…stopped being functional, when compared with other more capable PNT equipment, almost the day is was delivered to the AOR in 2005.”

While the Puck is certainly a major improvement in SWAP and concept, it essentially provides the same two GPS signals and SAASM capability as provided by the DAGR, just in a smaller form factor, and it does away with the continuously vilified user interface. The Puck technology totally ignores current-day PNT, multi-GNSS platforms and the other 160 PNT signals available today. Review the GPS World 2013 Receiver Survey and you will only find a handful of receivers that are so incredibly limited, and they are invariably produced, you guessed it, for the U.S. government as part of a GPS program or alternate program of record.

MUE: How Not to Build a PNT Device, or Why Warfighters Use Garmins and iPhones

The list you are looking at now is comprised of the first 15 minutes of conversation with thousands of warfighters interviewed over the last 10 years — they just had to tell us what was wrong with the current MUE before they finally got around to telling us what, if they were king or queen for a day, they wanted to see in the PHPNTT. This is not my opinion but the actual words of the warfighters. First of all, understand that the PLGR is a single-frequency GPS-only receiver with a security module (PPS-SM) to access encrypted P(Y)-code for anti-jam purposes. It was initially fielded 1990-2004, replaced by the DAGR in 2005. There are approximately 165,000 PLGRs and 450,000 DAGRs fielded at a cost of more than $1 billion. Now the warfighter comments:

• Both the PLGR and DAGR have an antiquated, proprietary OS and “extremely unfriendly — non-intuitive” user interface.
• PLGR and DAGR are not functional as handheld units but function well as embedded devices — although typically not networked, and we are not even sure they can be networked.
  • Example: One STRYKER vehicle variant has nine separate DAGRs incorporated, each with its own antenna and operating totally independently of the others.
• PLGR was decertified by U.S. Marine Corps in 2010 due to friendly-fire incidents.
• DAGR used today primarily as embedded device only with a “ horrible user interface”:
  • Monochrome screen, no active maps, navigation direct waypoint only.  Provides user with PNT information as coordinates — requires paper map to be an effective tool.
  • For other than straight-line navigation — time, distance and ETA are incorrect.
  • Programming/mission planning require special cables, software and a laptop computer.
  • Additional cables, radios and hardware are required for PLGR or DAGR to communicate.
  • Proprietary OS — no capability for additional programs to be added or utilize.
  • SWAP issues — large, heavy, limited battery life (multiple batteries) for typical missions.
  • TTFF — warm, approximately 2 minutes; cold with almanac download, 30+ minutes.
  • Position accuracy expressed as PDOP (1-6) on separate screen from PNT data. Nominal accuracy of a coded DAGR is typically about 1 meter or more.
• Advantages: Anti-jam and legacy interface capabilities.

So, the bottom line as far as the warfighters are concerned is that if you want to operate legacy equipment that requires a GPS input, such as calling in “fires” or artillery or if you are in a jamming environment, then you need the DAGR or its capability. Our survey shows, however, that only 1 in 40 use the DAGR as a handheld, and yet every single one of our respondents — that’s 100 percent, a rarity in statistics — stated they had a backup unit, primarily a Garmin, until 2005, and then popular backup units were more than likely an iPhone, iPad or Trimble unit.

One of the Most Popular PNT Devices in Theater Today – More than 365M Sold to Date

Today there is no question concerning the most prevalent PNT unit in both AORs. It is, you guessed it, the Apple iPhone and/or the Apple iPad. Let’s take a brief look at the capabilities of this non-ruggedized but still amazing device, which can easily be made Mil-Spec rugged with aftermarket cases and enclosures such as those produced by Otterbox, which I have personally tested and reviewed numerous times.

The Apple iPhone 5.

The attributes you see listed here are for the iPhone and iPad, and are those that assist in some aspect of PNT and/or integrity and accuracy.

• Assisted GPS SBAS — WAAS (PNT)
• Assisted GLONASS — (SBAS) (PNT)
• Digital compass (PN)
• Wi-Fi (Communications-Data + PNT)
• Cellular (Communications-Data + PNT)
• Bluetooth (Communications-Data + PNT)
• Skyhook Wireless (PNT)
• Three-axis gyro (PN)
• Accelerometer (PN)
• Pedometer (PN) – Application
• Internet (Communications-Data) Skype application (PNT)
• Real-time accuracy and integrity representation (PN)
• 361+ navigation applications in the App Store ready for instant download and designed for iPhone and iPad. The majority of these applications are available at no cost to the user.
• Real-time 3-D maps — Google maps — satellite imagery — updated continuously
• Automatic location-based services (LBS) — warfighter support
• BFT (Blue Force Tracking) + other .mil App Store apps including multiple mil-GRID systems.
• Warfighter discounts and mil-spec hardened cases (http://www.apple.com/r/store/government/).
• One-button combat application.

All this capability available in just four ounces — truly a SWAP and capability revolution.

Of course, what really makes the list of iPhone and iPad capabilities revealing is that the first two attributes alone more than double the number of PNT signals received and utilized by the iPhone versus the DAGR, and that number does not account for the GPS L2C (second civilian signal) and L5 (DOT safety of life signal) with CNAV, which when activated will be the strongest GPS signal broadcast to date. The CNAV data is an upgraded version of the original NAV or navigation message. It contains higher precision representation and nominally more accurate data than the nominal NAV data. There are 26 more PNT satellite signals available today in the iPhone and iPad, and they are comprised of multi-GNSS signals and augmentations. The kicker for me is that in addition to all the additional space signals are terrestrial signals, and almost any map or grid system the user desires. Plus there are apps (software applications) that translate between grid systems. And if you don’t like the interface of the navigation program you are using, then there are literally 360+ other choices. I also find the pedometer function interesting, in that firefighters now use this capability along with the Blue Force Tracking app in buildings when they are momentarily without GPS, GLONASS (Russian GNSS), WAAS (U.S. Wide Area Augmentation System), EGNOS (European Geostationary Navigation Overlay Service) or other SBAS (Satellite Based Augmentation System) signals.

Realistically, to defeat the current unencrypted MUE today, an adversary only has to jam one GPS signal, but to defeat the iPhone or iPad an adversary has to jam all the GPS signals, all the GLONASS signals, all the Wi-Fi signals, all the mobile 3G and 4G CDMA and GSM (read as different mobile telephone systems) signals and still the iPhone or iPad will use the accelerometer, gyro, compass and pedometer functions to determine position. Indeed, it will continue to function as a PNT device. All this in just four ounces at a cost about one-sixth of the DAGR displayed on a screen that has 100 times greater resolution and is in color. Remember, the DAGR has a monochrome screen. No contest. Plus try saying, “Take me home, Siri” to a DAGR and see what happens.

Garmin

What about Garmin, you ask? At the beginning of the current conflicts, Garmins were the prevailing additional PNT device. There are still thousands of them in theater, and they have saved many lives, as we will see. However, just look at this sales chart for smart PNT devices.

Products                                                             Total Units Sold (approximate)

iPhone (since 2005)                                            250,600,000 (M)

iPad (since 2010)                                                115,000,000 (M)

Garmin Sales                                                     ~100,000,000 (M)

iPhone/iPad App Store (since 2008)

Downloads of the 361+ navigation apps         2,200,000,000+ (B)

(Note: Total App Store downloads will exceed 50 billion by the time this is published.)

The Future

The future of PNT devices globally, especially for warfighters and first responders, is clearly with rugged mobile devices capable of downloading, storing, updating and utilizing applications. The Garmin cannot do that, although it can be updated, and just look at the numbers. Garmin started business as a GPS device provider in 1989. In that time, while branching out into marine and aviation devices, some of the best in the world for those purposes, they are still primarily GPS only (with SBAS). They have sold approximately 100M devices in 24 years compared to Apple’s iPhone and iPad numbers, which total more than 365M devices in less than eight years. The iPad alone outsold all Garmin products in just three years. I confess that I happily own several Garmins, think that are fantastic PNT devices, and it is really tough to beat the $99 wrist Garmin. When all is said and done, the Garmin gives you better information in a non-jamming environment than the DAGR. And Garmin units are still saving lives. Take this vignette from SSG Kyle Dorsch:

“My name is SSG Kyle Dorsch…a Reconnaissance team leader in the 2-30 Infantry Battalion, 10th Mountain Division, deployed to the Logar province, Afghanistan. I have used my Garmin eTrex Vista H throughout my deployment…it has been a lifesaver in more than a literal sense. In fact, there isn’t a leader in our establishment without a Garmin product…my Garmin guided me and my four-man team seamlessly through some of the toughest areas of Afghanistan…it also literally saved my life.”

SSG Dorsch goes on to explain that the eTREX, which was placed strategically on his combat vest, actually stopped an enemy bullet meant for him, and just like Timex the eTREX kept on ticking.

My Obligatory Caveat

Note that SSG Dorsch has always had a Garmin with him in theater and indicates that his leadership has as well. There is no doubt the eTrex saved his life, literally. However, I would never tell a warfighter to not use their government-issued MUE. In a severe jamming environment, it may prove to be a lifesaver, and it may be the only equipment that interfaces with legacy communications and fire support equipment. Take that advice for what it is worth today, because hopefully this will not be the case much longer.

DARPA and Smart COTS Devices on the Battlefield Now

DARPA (the Defense Advanced Research Projects Agency, the real inventors of the Arpanet and the Internet), a much-storied DoD research arm, launched an effort recently called “Transformative Apps.” It developed a few dozen smart applications that work on a number of mobile devices. In addition to mapping, navigation and smart routes, the apps identify explosives and various weapons, and help navigate and locate parachute drops.

A screenshot of the DARPA Smart Routes application. The green routes are safe routes and the red are routes that have been traveled too many times or indicate where problems may exist.

DARPA builds prototypes that are transferred to the Services and become official applications used by hundreds of thousands of warfighters. The challenge is to rapidly adapt COTS (commercial off-the-shelf) technology to the unique circumstances of the military, which often operates over large, hostile areas with little to no formal communications infrastructure.

DARPA reports that more than 1,000 war fighters in Afghanistan now use the DARPA Transformative Apps technology as it continues to be rolled out to the Services.

The most interesting aspect of DARPA’s participation in PNT software is that it will definitely accelerate the multi-GNSS and all-signals-available scenario, because it is  constrained by woefully out-of-date DoD regulations. DARPA does what is smart, what cutting-edge technology will support, what makes sense, and ultimately what saves lives.

This good bit of news from DARPA combined with the following statement from the DoD in the Wall Street Journal earlier this month should give us all some hope for the future of PNT and MUE.

Pentagon Expects to Enlist Apple, Samsung Devices

The U.S. Department of Defense expects in coming weeks to grant two separate security approvals for Samsung’s Galaxy smartphones, along with iPhones and iPads running Apple’s latest operating system — moves that would boost the number of U.S. government agencies [ed. legally] allowed to use those devices.

–  Wall Street Journal, May 2, 2013

In my humble opinion, this announcement is simply outstanding…albeit about 10 years late to need. Indeed, Ms. Teri Takai, the current DoD CIO (Chief Information Officer) gest it and is trying hard, but she can’t do all the heavy lifting alone.

Old Adages Die Hard

I remember an old GPS adage that portentously proclaimed, “If it is not supported on the GPS satellite, it cannot be supported in the user equipment.” Unfortunately, there are those still holding to this totally fallacious belief. Today in the current budget environment, amazing capabilities are being implemented with user equipment that multiply the capabilities of the PNT satellite, other satellites and space signals, terrestrial signals and synergistic augmentations. Indeed, the total price of the PLGR and DAGR program combined would barely pay for some NRE (non-recurring engineering) costs and two launches of the GPS III satellites that should be ready for launch in 2014. Today we need to look even harder at what is doable with user equipment, especially in the military, because it is all we can afford. As Winston Churchill was once quoted as saying, “Gentlemen, we have run out of money; now we have to think.” However, having said that, let’s not forget that the multi-GNSS environment has multiplied many fold the number and capabilities of PNT signals on orbit today.

PNT User Equipment TRENDS — Space SIGNALS available

Jim Doherty, USCG Captain retired, and I are friends and colleagues at the Institute for Defense Analyses (IDA). We are both old retired navigators as well. We both still have the skills to successfully navigate an aircraft or ship, for that matter, from San Francisco to Tokyo using only a sextant. While we are proud of that talent or ability, one that very few possess today, we would much rather accomplish the feat with an exceptional multi-GNSS device, and they exist today like never before. These next lists show all the signals that are available today compared to what the GPS MUE can receive and use for PNT purposes. Plus, Jim and I both share a firm belief in another old navigators’ adage: Receive Everything – Trust Nothing!

Civil-commercial multi-GNSS UE receives more space and terrestrial signals than U.S. GPS MUE.

• GPS MUE “officially” utilizes L1(CA), L2 P(Y) with SAASM.
  
• There are NO commercially viable M-code receivers available today and there will not be for several years to come.

PNT civil UE philosophy: Track and use all PNT signals available.

• GPS L1-CA/L2-codeless and ready for L2C, L5, L1C (GPS III & QZSS)
• SBAS (WAAS, EGNOS, MSAS, GAGAN, SDCM) + NDGPS & many other augmentations
• GLONASS L1/L2/L5
• Galileo E1/E5 (CBOC & Alt BOC)
• Compass B1/B2/B3 (carrier signals only- no full signal specifications)                           
• QZSS (Japanese GEO – highly elliptical) broadcasting L1 CA/C/SAIF, L2C, L5, LEX Pilot
• Wi-Fi, 3G-4G, Skyhook, eLORAN (UK), networks, CORS, VRS, GVRS

And do not be deceived: there are plenty of PNT receivers available today to receive all these signals and they have existed for some time. Equipment manufacturers have been ready to receive, process and utilize all the GPS and multi-GNSS signals for years. For example, Trimble built and shipped an L2C receiver in 2003, and that signal has still not been activated on any U.S. GPS payloads although, as we heard from Major General Marty Whelan (USAF – AFSPC/A5) earlier today, General Shelton (USAF), the four-star commander at AFSPC (Air Force Space Command) has announced a six-week test of the L2C signal and full CNAV message in June of this year. A great step forward.

One of these days we might even catch-up with the Japanese – more on that in a moment.

Trimble built and shipped receivers for GLONASS signals in 2006, even though GLONASS did not reach FOC or Full Operational Capability until late in 2010. A designation it is having serious problems maintaining. Trimble also ships L5 receivers as well as commercial SBAS receivers that result in extremely accurate and reliable positions. Lest you think all these signals have gone to waste, remember that Japan’s QZSS-1 broadcasts both L2C and L5 with a full CNAV message today, and the Trimble receivers and others with the multi-GNSS capability work well with those signals, as we shall see.

Global Virtual Reference Stations

Trimble (VRS) and John Deere (StarFire) PNT receivers have the capability Trimble has designated as Global Virtual Reference Stations, which — along with real-time kinematic (RTK) processing — provide users with an unprecedented number of signals and a real-time processed signal with corrections. This results in centimeter-level accuracy for any of their receivers that have the capability to receive and process the signals. For both manufacturers, that will soon be almost all of their receivers. Sure, there will probably be a small monthly fee involved, but the accuracy difference between 1 meter (~3 feet) and 3 centimeters can mean life and death if you are unlucky enough to be in the collateral damage zone or in the sights of a Hellfire missile during war time.

Multi-GNSS SVs and Signals in View

To highlight this point, just glance at the following graphical log file generated by software in the latest Trimble Multi-GNSS PNT receiver. The chart depicts a log file from a receiver located in Singapore. The location is significant only because in that location the receiver is in full view of the Japanese QZSS-1 PNT SV and all its extra U.S. originated PNT signals (L2C & L5) mentioned earlier. This particular Trimble receiver is networked and reports results automatically and continuously to a web page, while receiving GVRS updates and corrections plus other PNT information, such as an updated almanac, over the same network. The question becomes, is it a PNT device with a computer and embedded communications? Or is it a computer with communications and an embedded PNT function? You be the judge. Regardless of which you choose, this is the future of PNT and MUE.

This civil receiver reports 40+ SVs with 169 separate signals in view and usable. This does not count the number of Wi-Fi and/or GVRS signals it is capable of receiving. Meanwhile, a GPS MUE receiver in the same location only observes a total of 10 SVs it can process for a total signal count of 20. However, one of the key points on this log depiction has to do with integrity. Notice the orange and red lines. They indicate that the receiver has labeled these signals as “suspect” and has automatically dropped them from the solution for any of a host of reasons — a failed integrity check, jamming, spoofing, wrong way path, a runaway clock, etc. You name it, and if it is suspicious, the receiver will drop that SV and its signals from its PNT calculations. Built-in integrity.

The obvious question becomes just how accurate is this Trimble receiver over a 24-hour period? The next graphical log file denotes that it is accurate within 3 centimeters.

Trimble multi-GNSS receiver web page log file denotes continuous availability of PNT signals with an average accuracy of 3 cms.

Assured PNT

When we asked warfighters what was more important to them in a combat zone — availability or accuracy of the PNT signals, the answer was, not surprisingly, both. But, of course, they need to receive the signal first, and then they can worry about accuracy.

So, if you were Ms. Teri Takai and you were worried about “assured PNT,” would you rather do that with 20 signals from 10 SVs or 169 signals from 49 SVs and some very strong, difficult to jam, terrestrial signals as well — adding up to, on average, 33 times more accuracy than the GPS-only signal? To me, the answer is obvious. And of course, all that is on the line with every mission the DoD performs, as is the safety of our critical national infrastructure as this next chart depicts.

• Assured PNT or lack thereof impacts all missions, across all platforms and domains
• Assured GPS MUE PNT today depends on:
  • L1(C/A), L2 P(Y), SAASM (Future M-Code)
  • Accuracy ~ 1m

• Assured Multi-GNSS MUE PNT with all signals available depends on:
  • GPS L1/L2/L5/L1C/L2C/M-Code/SAASM
  • SBAS (WAAS, EGNOS, MSAS, GAGAN, SDCM+)
  • GLONASS L1/L2/L5
  • Galileo E1/E5 (CBOC & Alt BOC)
  • Compass B1/B2/B3
  • QZSS GEO – L1 CA/C/SAIF, L2C, L5, LEX Pilot
  • Two-way communications, Networking, PNT servers, each PNT device with unique IP address and each PNT device serves as a sensor
  • Software definable devices
  • Multiple software applications (Apps)
  • Accuracy ~ 3 cm

Army Making Strides

I spoke above about DARPA getting into the PNT business, and that is a good thing. But how about the largest military user of PNT, the United States Army? The U.S. Army is making some interesting changes as well. The Army announced a few months ago that there would be no more purchases of DAGRs, and that it was pursuing smartphones as a communications and small computing platform as well as an alternate PNT tool and display device. This is where the Puck comes into play.

Inside the Puck.

While it is a wonderful idea I fully endorse, the problem with the Puck is that under the current design scheme it will still only transmit the current two GPS signals to a smartphone or other PNT display device. And warfighters lament that it is another device run by batteries for which our warfighters need to carry spares. Why not make the Puck a multi-GNSS device? we asked. The answer we received is that it would make it too power hungry and just require more batteries. So to misquote Shakespeare “…for want of a battery, the war was lost?” The Army is definitely on the right track, but they need to figure out how to make the Puck a multi-GNSS device. Can you say Lithium ION and solar charger – Hoorah!?

The Army Hub

The Puck is moving in the right direction. However, with the addition of another device, the Army is definitely on the right track. This device is designated the “Hub,” and while it is again GPS-oriented, it contains multiple terrestrial and internal signal augmentations and backups, as the image depicts.

Inside the U.S. Army’s Hub.

With apologies to the U.S. Army, I unabashedly modified the chart, and I made it very obvious. The red text depicts my addition of a multi-GNSS card or module versus or in addition to the CGM (Common GPS Module) and GB-GRAM or Ground-Based GPS Receiver Application Module. The multi-GNSS card/module already exists today. Several PNT receiver manufacturers manufacture it with 28-nm technology versus the 95-nm technology — for the as-yet-unavailable for about four more years if the rumors are correct — GPS-only CGM. For me, the addition seems to be an easy fix, as there is lots of room in the Hub. But this fix or module (CGM) is years and millions of dollars down the road, versus a solution that exist today.

YUMA 2 or Hub or Both

The solution, frankly, is one of the smart tablets available today from numerous manufacturers — seven, actually, that have the wherewithal to produce a secure multi-GNSS device with a SAASM module.

The Trimble Yuma 2.

The Army Hub.

This is an example of the solution in the form of a Yuma 2 tablet computer from Trimble, which I am in the processing of reviewing for GPS World. The Yuma 2 has all the multi-GNSS features we have been discussing and more, plus it can in time accommodate all the modules scheduled to be incorporated into the Hub. Why build a whole new display device when the core already exists with many more capabilities than were imagined or real estate would ever allow for the Hub? Plus, it is available today as a rugged Mil-Spec device with a full color, high-resolution touch screen. And in the end it will provide a 3-cm solution versus a 1-meter solution. What more could you want? And it is available today with an outstanding and intuitive interface.

Conclusion – Services PNT UE Trends

I have been focusing on the Army today not simply because they are the biggest U.S. military user of PNT devices, but because they are moving in the right direction for the future of PNT and MUE devices. Of course, all the services and many agencies need a well-thought-out and secure PNT solution, and if we have learned anything it is that one size does not fit all. Indeed, our national security and our national infrastructure depend upon future PNT devices. For security purposes alone, they should have a certain degree of application and signal diversity.

Now let’s review:

• Army has a way ahead with an assured PNT program.
  • Includes end of PLGR and DAGR and adding new networkable devices.
  • Plans for fourth-generation multi-GNSS and multi-function handheld devices and embedded PNT devices as sensors to include the Puck and Hub.
• Marine Corps: Decertified PLGRs in 2009 and attempts to limit the use of DAGRs.
  • DAGRs used primarily as embedded devices.
  • Purchasing approved SAASM devices from commercial vendors.
• USAF: Outfitted 70% of aircraft with modern, integrated, networkable and upgradeable PNT devices.
• Navy: More than 60% of the fleet outfitted with modern PNT networked devices.
• The Bottom Line is – One size does not fit all but one conclusion is clear – while GPS may and will always hopefully be the Gold Standard – multi-GNSS solutions are the future.

The Future of PNT Devices

This last list depicts the future of PNT as best as I can define it; indeed, as it has already been defined for us by our warfighters and first responders or, as Kirk Lewis would have me say, government users. The users are not waiting around, nor have they bothered to adhere to woefully out-of-date regulations. It is what they desire, and since their lives depend on it, it is what they should have.

• Multi-GNSS — Utilize all PNT signals available.
  • Space and Terrestrial (GPS, GLONASS, eLORAN).
  • Traditional and non-traditional (Wi-Fi, GVRS, carrier signals).
• Multi-function COTS devices with non-proprietary OS (operating System), intuitive interfaces and Mil-Spec ruggedized.
  • Multiple methods of communications: Wi-Fi, Skype, 4G, text, auto-text, satellite.
• Software Downloads – Applications
  • COTS applications plus .mil apps store.
• Networked devices for SA, updates and PNT,
  • Real-time satellite imagery and mission data injects.
  • Defense and intelligence LBS.
• Each device will be a sensor on a network,
  • Automatically report jamming, interference and location data.
• Utilize SAASM and anti-jam military signals only as required.

Thanks you for your time and kind attention today. And remember, Happy Navigating!

The spectrum of today’s providers seems to range from highly sophisticated scientific systems used for development by precision receiver manufacturers, through systems with GNSS and aiding solutions, to specialized systems for both general and specific application developers and also for production test. So this month I’d like to try to summarize (in no particular order) what some of the suppliers of GNSS simulation systems are up to, how they may be positioned in the market and, wherever possible, what we might expect to see from them in the future.

GSG Series 6 GNSS simulator.

Spectracom is a more recent entrant to the GNSS simulation market, though the company has been providing frequency and time synchronization test equipment for about 40 years. Spectracom has integrated GPS into these products for more than ten years, and decided three years ago to use the knowledge it had gained to get into the GNSS simulation business.

The GSG family of simulators is positioned at the “affordable” end of the simulation equipment scale, and is targeted at users and integrators of GNSS, rather than developers of receivers. Spectracom claims to have about 80 percent of the features of the top-end simulations systems, but its more capable (Series 6) systems sell in the $20-30k range. While new to the business, the Spectracom team feels that this allows them to bring the newest technology and innovation to the market.

The Spectracom system is derived from its well-known frequency/time synthesizer equipment — in fact, it has the same look front panel and chassis — and also makes use of the same “easy-to-use” concepts. “It doesn’t take a navigation scientist to operate these simulators,” said John Fischer, chief technology officer at Spectracom. The accompanying Studio View software is reportedly relatively easy to use to generate trajectories and other test scenarios by connecting to Google Maps and uploading them to the simulator.

But with all new firmware and FPGA implementation, 64 channels, and four frequency bands covering both GPS and GLONASS, the GSG family appears to be very well positioned for application developers integrating GNSS. Galileo and Beidou/Compass are in the works and expected this year, and will be supplied as upgrades to existing equipment.

Spectracom anticipates significant growth in its target market for application developers in “anything that moves,” including automotive and airborne, video matching, radar/lidar, and handheld nav devices, including mobile phones. Spectracom has a number of product lines and around 100 people working for them, but the GNSS simulation group is around 12 strong.

Rohde & Schwarz is another relatively recent GNSS simulation entrant with new products for the market.

SMBV100A vector signal generator.

Its current offering — the SMBV100A Vector Signal Generator – can simulate 24 dynamic GPS, GLONASS and Galileo satellites.  The SMBV 100A has wide bandwidth and high output power levels. Real-time test scenarios can be customized by the user — including a neat facility that allows modeling of satellite masking by downtown buildings, along with anticipated multipath for the same urban scenario.

While somewhat new to GNSS simulation, R&S has been around since the 1930s, and its experience with frequency synthesizers and similar equipment is being carried forward into what the company terms its “cost-effective” GNSS simulation offerings. R&S anticipates significant growth in automotive, aerospace, UAV, and cellular assisted-GNSS application markets.

R&S has had success in the aerospace market for UAVs, and has developed the capability to model antenna patterns and UAV body mask as the vehicle rotates and attitude changes towards visible satellites. Along the same lines, R&S has hooked up its system to flight simulators and provided hardware-in-the-loop testing for clients. R&S also has the ability to run simulation scenarios for long periods of time, and for “very long” periods if the receiver is stationary — this feature makes use of large internal memory storage within the SMBV100A; of course, almanac validity limits just how long this is possible. P-code capability is provided as an option, and there is a roadmap for adding SBAS and Beidou capability later.

IFEN NavX-NCS Professional

In the meantime, IFEN in Germany is focusing on its NavX-NCS Navigation Constellation Simulator range of multi-GNSS signal simulators.

IFEN emphasizes the flexibility of its design, with a platform scalable from a 12-channel GPS L1 system up to a full multi-GNSS system with 108 channels and 9 frequencies for GPS, GLONASS, Galileo, QZSS and SBAS. With this building-block approach, channels and capabilities can be added as and when additional testing complexity is required.

IFEN claims that the capability to generate all GNSS signals — by combining different modulations with up to nine L-band frequencies — is the only existing solution on the market providing GPS, Galileo, GLONASS, QZSS and SBAS in one chassis at the same time. And, since April 2013, all IFEN NavX-NCS GNSS RF signal simulators are to include BeiDou B1 signal capability in accordance with the official Chinese BeiDou B1 ICD, and are ready for the other B2 and B3 BeiDou signals.

IFEN also founded a subsidiary in the USA in January this year called IFEN, Inc., located in California and operational with Mark Wilson (formerly with Spirent) as VP Sales. In addition, IFEN has formed a partnership with WORK Microwave — a leading European manufacturer of advanced satellite communications and navigation equipment. WORK Microwave is responsible for RF and digital hardware design while IFEN develops the associated software and manages the distribution of the product range.

Little-known IP-Solutions in Tokyo, Japan, has been working to develop its ReGen GNSS DIF signal simulator, a software simulator that simulates ionospheric effects, generates digital IF (DIF) signals similar to those recorded by an RF recorder, and comes with an optional capability of simulating integrated inertial navigation.

IP-Solutions’ digital IF baseband signal simulator ReGen has been developed in close cooperation with the Japan Aerospace Exploration Agency (JAXA) to test and validate GNSS signal processing algorithms and methods for use on board aircraft using tight and ultra-tight integration with INS, including specific scintillation models and ionospheric bubble simulation.

Actual recorded flight data (left), ReGen replicated flight data (right).

Various configurations of ReGen can produce multichannel GPS and GLONASS L1 signals and single-channel GPS L1, L2, L5 and GLONASS L1 and L2 signals, as well as simulating noise and interference.

Meanwhile, Spirent, arguably the original market leader in GNSS simulation, has continued along its chosen path of supplying the industry with the greatest capability and most extensive simulation systems.

Spirent has recently released test systems with support for China’s BeiDou Navigation Satellite System in addition to GPS, GLONASS and Galileo.

Spirent started shipping BeiDou-ready systems to its customers in 2012. Now these may be upgraded to full BeiDou capability using the information available in the first full issue of the BeiDou-2 Signal In Space Interface Control Document (ICD).

Also aiming at mobile applications, Spirent’s Hybrid Location Technology Solution (HLTS) integrates Wi-Fi, Assisted Global Navigation Satellite System (A-GNSS), Micro Electro-Mechanical Systems (MEMS) sensor and cellular positioning technologies. HLTS integrates four very different and distinct location technologies and provides repeatable and reliable lab-based characterization of mobile devices supporting hybrid location technologies that will enable “accurate everywhere” location — including indoor user location determination.

Other notable players in the GNSS simulation business include Racelogic, CAST Navigation and Agilent who are each pursuing their chosen niches in this expanding market segment. Racelogic’s LabSat GPS simulator is gaining popularity with a number of leading companies, providing the ability to record and replay real GNSS RF data as well as user-generated scenarios. CAST has an extensive line-up of GPS and GPS/INS simulation systems and support software, and Agilent has added to its impressive electronic testing portfolio with a very capable looking GPS simulation product line.

Several other companies — some based in China and Russia — are also trying to figure out their development and marketing strategies to conquer their chosen GNSS simulation market niche. This is all a very healthy sign that there are many other companies with new embedded GNSS applications that they are bringing to market and who therefore need GNSS simulation/test capability. Overall, this means there is still significant growth underway and far wider applications of GNSS on their way to market. Great news for the GNSS industry!

Tony Murfin
GNSS Aerospace

By Mathieu Raimondi, Eric Sénant, Charles Fernet, Raphaël Pons, Hanaa Al Bitar, Francisco Amarillo Fernández, and Marc Weyer

INNOVATION INSIGHTS with Richard Langley

INTEGRITY.  It is one of the most desirable personality traits. It is the characteristic of truth and fair dealing, of honesty and sincerity. The word also can be applied to systems and actions with a meaning of soundness or being whole or undivided. This latter definition is clear when we consider that the word integrity comes from the Latin word integer, meaning untouched, intact, entire — the same origin as that for the integers in mathematics: whole numbers without a fractional or decimal component.

Integrity is perhaps the most important requirement of any navigation system (along with accuracy, availability, and continuity). It characterizes a system’s ability to provide a timely warning when it fails to meet its stated accuracy. If it does not, we have an integrity failure and the possibility of conveying hazardously misleading information. GPS has built into it various checks and balances to ensure a fairly high level of integrity. However, GPS integrity failures have occasionally occurred.

One of these was in 1990 when SVN19, a GPS Block II satellite operating as PRN19, suffered a hardware chain failure, which caused it to transmit an anomalous waveform. There was carrier leakage on the L1 signal spectrum. Receivers continued to acquire and process the SVN19 signals, oblivious to the fact that the signal distortion resulted in position errors of three to eight meters. Errors of this magnitude would normally go unnoticed by most users, and the significance of the failure wasn’t clear until March 1993 during some field tests of differential navigation for aided landings being conducted by the Federal Aviation Administration. The anomaly became known as the “evil waveform.”

(I’m not sure who first came up with this moniker for the anomaly. Perhaps it was the folks at Stanford University who have worked closely with the FAA in its aircraft navigation research. The term has even made it into popular culture. The Japanese drone-metal rock band, Boris, released an album in 2005 titled Dronevil. One of the cuts on the album is “Evil Wave Form.” And if drone metal is not your cup of tea, you will find the title quite appropriate.) Other types of GPS evil waveforms are possible, and there is the potential for such waveforms to also occur in the signals of other global navigation satellite systems. It is important to fully understand the implications of these potential signal anomalies. In this month’s column, our authors discuss a set of GPS and Galileo evil-waveform experiments they have carried out with an advanced GNSS RF signal simulator. Their results will help to benchmark the effects of distorted signals and perhaps lead to improvements in GNSS signal integrity.

“Innovation” is a regular feature that discusses advances in GPS technology andits applications as well as the fundamentals of GPS positioning. The column is coordinated by Richard Langley of the Department of Geodesy and Geomatics Engineering, University of New Brunswick. He welcomes comments and topic ideas.

GNSS signal integrity is a high priority for safety applications. Being able to position oneself is useful only if this position is delivered with a maximum level of confidence. In 1993, a distortion on the signals of GPS satellite SVN19/PRN19, referred to as an “evil waveform,” was observed. This signal distortion induced positioning errors of several meters, hence questioning GPS signal integrity. Such events, when they occur, should be accounted for or, at least, detected.

Since then, the observed distortions have been modeled for GPS signals, and their theoretical effects on positioning performance have been studied through simulations. More recently, the models have been extended to modernized GNSS signals, and their impact on the correlation functions and the range measurements have been studied using numerical simulations. This article shows, for the first time, the impact of such distortions on modernized GNSS signals, and more particularly on those of Galileo, through the use of RF simulations. Our multi-constellation simulator, Navys, was used for all of the simulations.

These simulations are mainly based on two types of scenarios: a first scenario, referred to as a static scenario, where Navys is configured to generate two signals (GPS L1C/A or Galileo E1) using two separate RF channels. One of these signals is fault free and used as the reference signal, and the other is affected by either an A- or B-type evil waveform (EW) distortion (these two types are described in a latter section).

The second type of scenario, referred to as a dynamic scenario, uses only one RF channel. The generated signal is fault free in the first part of the simulation, and affected by either an A- or B-type EW distortion in the second part of the scenario. Each part of the scenario lasts approximately one minute.

All of the studied scenarios consider a stationary satellite position over time, hence a constant signal amplitude and propagation delay for the duration of the complete scenario.

Navys Simulator

The first versions of Navys were specified and funded by Centre National d’Etudes Spatiales or CNES, the French space agency. The latest evolutions were funded by the European Space Agency and Thales Alenia Space France (TAS-F). Today, Navys is a product whose specifications and ownership are controled by TAS-F. It is made up of two components: the hardware part, developed by ELTA, Toulouse, driven by a software part, developed by TAS-F.

The Navys simulator can be configured to simulate GNSS constellations, but also propagation channel effects. The latter include relative emitter-receiver dynamics, the Sagnac effect, multipath, and troposphere and ionosphere effects. Both ground- and space-based receivers may be considered.

GNSS Signal Generation Capabilities. Navys is a multi-constellation simulator capable of generating all existing and upcoming GNSS signals. Up to now, its GPS and Galileo signal-generation capabilities and performances have been experienced and demonstrated. The simulator, which has a generation capacity of 16 different signals at the same time over the entire L band, has already been successfully tested with GPS L1 C/A, L1C, L5, and Galileo E1 and E5 receivers.

Evil Waveform Emulation Capabilities. In the frame of the ESA Integrity Determination Unit project, Navys has been upgraded to be capable of generating the signal distortions that were observed in 1993 on the signals from GPS satellite SVN19/PRN19. Two models have been developed from the observations of the distorted signals.

The first one, referred to as Evil Waveform type A (EWFA), is associated with a digital distortion, which modifies the duration of the GPS C/A code chips, as shown in FIGURE 1. A lead/lag of the pseudorandom noise code chips is introduced. The +1 and –1 state durations are no longer equal, and the result is a distortion of the correlation function, inducing a bias in the pseudorange measurement equal to half the difference in the durations. This model, based on GPS L1 C/A-code observations, has been extended to modernized GNSS signals, such as those of Galileo (see Further Reading). In Navys, type A EWF generation is applied by introducing an asymmetry in the code chip durations, whether the signal is modulated by binary phase shift keying (BPSK), binary offset carrier (BOC), or composite BOC (CBOC).

FIGURE 1. Theoretical L1 C/A code-chip waveforms in the presence of an EWFA (top) and EWFB (bottom).

The second model, referred to as Evil Waveform type B (EWFB) is associated with an analog distortion equivalent to a second-order filter, described by a resonance frequency (fd) and a damping factor (σ), as depicted in Figure 1. This failure results in correlation function distortions different from those induced by EWFA, but which also induces a bias in the pseudorange measurement. This bias depends upon the characteristics (resonance frequency, damping factor) of the filter. In Navys, an infinite impulse response (IIR) filter is implemented to simulate the EWFB threat. The filter has six coefficients (three in the numerator and three in the denominator of its transfer function). Hence, it appears that Navys can generate third order EWF type B threats, which is one order higher that the second order threats considered by the civil aviation community. Navys is specified to generate type B EWF with less than 5 percent root-mean-square  (RMS) error between the EWF module output and the theoretical model. During validation activities, a typical value of 2 percent RMS error was measured. This EWF simulation function is totally independent of the generated GNSS signals, and can be applied to any of them, whatever its carrier frequency or modulation.

It is important to note that such signal distortions may be generated on the fly — that is, while a scenario is running. FIGURE 2 gives an example of the application of such threat models on the Galileo E1 BOC signal using a Matlab theoretical model.

FIGURE 2. Theoretical E1 C code-chip waveforms in the presence of an EWFA (top) and EWFB (bottom).

GEMS Description

GEMS stands for GNSS Environment Monitoring Station. It is a software-based solution developed by Thales Alenia Space aiming at assessing the quality of GNSS measurements. GEMS is composed of a signal processing module featuring error identification and characterization functions, called GEA, as well as a complete graphical user interface (see online version of this article for an example screenshot) and database management.

The GEA module embeds the entire signal processing function suite required to build all the GNSS observables often used for signal quality monitoring (SQM). The GEA module is a set of C/C++ software routines based on innovative-graphics-processing-unit (GPU) parallel computing, allowing the processing of a large quantity of data very quickly. It can operate seamlessly on a desktop or a laptop computer while adjusting its processing capabilities to the processing power made available by the platform on which it is installed. The GEA signal-processing module is multi-channel, multi-constellation, and supports both real-time- and post-processing of GNSS samples produced by an RF front end.

GEMS, which is compatible with many RF front ends, was used with a commercial GNSS data-acquisition system. The equipment was configured to acquire GNSS signals at the L1 frequency, with a sampling rate of 25 MHz. The digitized signals were provided in real time to GEMS using a USB link.

From the acquired samples, GEMS performed signal acquisition and tracking, autocorrelation function (ACF) calculation and display, and C/N₀ measurements. All these figures of merit were then logged in text files.

EWF Observation

Several experiments were carried out using both static and kinematic scenarios with GPS and Galileo signals.

GPS L1 C/A. The first experiment was intended to validate Navys’ capability of generating state-of-the-art EWFs on GPS L1 C/A signals. It aimed at verifying that the distortion models largely characterized in the literature for the GPS L1 C/A are correctly emulated by Navys.

EWFA, static scenario. In this scenario, Navys is configured to generate two GPS L1 C/A signals using two separate RF channels. The same PRN code was used on both channels, and a numerical frequency transposition was carried out to translate the signals to baseband. One signal was affected by a type A EWF, with a lag of 171 nanoseconds, and the other one was EWF free. Next, its amplified output was plugged into an oscilloscope. The EWFA effect is easily seen as the faulty signal falling edge occurs later than the EWF-free signal, while their rising edges are still synchronous. However, the PRN code chips are distorted from their theoretical versions as the Navys integrates a second-order high pass filter at its output, meant to avoid unwanted DC emissions. The faulty signal falling edge should occur approximately 0.17 microseconds later than the EWF-free signal falling edge.

A spectrum analyzer was used to verify, from a spectral point of view, that the EWFA generation feature of Navys was correct. For this experiment, Navys was configured to generate a GPS L1 C/A signal at the L1 frequency, and Navys output was plugged into the spectrum analyzer input. Three different GPS L1 C/A signals are included: the spectrum of an EWF-free signal, the spectrum of a signal affected by an EWF type A, where the lag is set to 41.1 nanoseconds, and the spectrum of a signal affected by an EWF type A, where the lag is set to 171 nanoseconds. As expected, the initial BPSK(1) signal is distorted and spikes appear every 1 MHz. The spike amplitude increases with the lag.

EWFA, dynamic scenario. In a second experiment, Navys was configured to generate only one fault-free GPS L1 C/A signal at RF. The RF output was plugged into the GEMS RF front end, and acquisition was launched. One minute later, an EWFA distortion, with a lag of 21 samples (about 171 nanoseconds at 120 times f₀, where f₀ equals 1.023 MHz), was activated from the Navys interface.

FIGURE 3 shows the code-phase measurement made by GEMS. Although the scenario was static in terms of propagation delay, the code-phase measurement linearly decreases over time. This is because the Navys and GEMS clocks are independent and are drifting with respect to each other.

FIGURE 3. GEMS code-phase measurements on GPS L1 C/A signal, EWFA dynamic scenario.

The second observation is that the introduction of the EWFA induced, as expected, a bias in the measurement. If one removes the clock drifts, the bias is estimated to be 0.085 chips (approximately 25 meters). According to theory, an EWFA induces a bias equal to half the lead or lag value. A value of 171 nanoseconds is equivalent to about 50 meters.

FIGURE 4 represents the ACFs computed by GEMS during the scenario. It appears that when the EWFA is enabled, the autocorrelation function is flattened at its top, which is typical of EWFA distortions. Eventually, FIGURE 5 showed that the EWFA also results in a decrease of the measured C/N₀, which is completely coherent with the flattened correlation function obtained when EWFA is on.

FIGURE 4. GEMS ACF computation on GPS L1 C/A signal, EWFA dynamic scenario.

FIGURE 5. GEMS C/N0 measurement on GPS L1 C/A signal, EWFA dynamic scenario.

Additional analysis has been conducted with Matlab to confirm Navys’ capacity. A GPS signal acquisition and tracking routine was modified to perform coherent accumulation of GPS signals. This operation is meant to extract the signal out of the noise, and to enable observation of the code chips. After Doppler and code-phase estimation, the signal is post-processed and 1,000 signal periods are accumulated. The result, shown in FIGURE 6, confronts fault-free (blue) and EWFA-affected (red) code chips. Again, the lag of 171 nanoseconds is clearly observed. The analysis concludes with FIGURE 7, which shows the fault-free (blue) and the faulty (red) signal spectra. Again, the presence of spikes in the faulty spectrum is characteristic of EWFA.

FIGURE 6. Fault-free vs. EWFA GPS L1 C/A signal.

FIGURE 7. Fault-free vs. EWFA GPS L1 C/A signal power spectrum density.

EWFB, static scenario. The same experiments as for EWFA were conducted for EWFB. Fault-free and faulty (EWFB with a resonance frequency of 8 MHz and a damping factor of 7 MHz) signals were simultaneously generated and observed using an oscilloscope and a spectrum analyzer. The baseband temporal signal undergoes the same default as that of the EWFA because of the Navys high-pass filter. However, the oscillations induced by the EWFB are clearly observed.

The spectrum distortion induced by the EWFB at the L1 frequency is amplified around 8 MHz, which is consistent with the applied failure.

EWFB, dynamic scenario. Navys was then configured to generate one fault-free GPS L1 C/A signal at RF. The RF output was plugged into the GEMS RF front end, and acquisition was launched. One minute later, an EWFB distortion with a resonance frequency of 4 MHz and a damping factor of 2 MHz was applied. As for the EWFA experiments, the GEMS measurements were analyzed to verify the correct application of the failure. The code-phase measurements, illustrated in FIGURE 8, show again that the Navys and GEMS clocks are drifting with respect to each other. Moreover, it is clear that the application of the EWFB induced a bias of about 5.2 meters on the code-phase measurement. One should notice that this bias depends upon the chip spacing used for tracking. Matlab simulations were run considering the same chip spacing as for GEMS, and similar tracking biases were observed.

FIGURE 8. GEMS code-phase measurements on GPS L1 C/A signal, EWFB dynamic scenario.

FIGURE 9 shows the ACF produced by GEMS. During the first minute, the ACF looks like a filtered L1 C/A correlation function. Afterward, undulations distort the correlation peak.

FIGURE 9. GEMS ACF computation on GPS L1 C/A signal, EWFB dynamic scenario.

Again, additional analysis has been conducted with Matlab, using a GPS signal acquisition and tracking routine. A 40-second accumulation enabled comparison of the faulty and fault-free code chips. FIGURE 10 shows that the faulty code chips are affected by undulations with a period of 244 nanoseconds, which is consistent with the 4 MHz resonance frequency. This temporal signal was then used to compute the spectrum, as shown in FIGURE 11. The figure shows well that the faulty L1 C/A spectrum (red) secondary lobes are raised up around the EWFB resonance frequency, compared to the fault-free L1 C/A spectrum (blue).

FIGURE 10. Fault-free vs EWFB GPS L1 C/A signal.

FIGURE 11. Fault-free vs EWFB GPS L1 C/A signal power spectrum density.

Galileo E1 CBOC(6, 1, 1/11). In the second part of the experiments, Navys was configured to generate the Galileo E1 Open Service (OS) signal instead of the GPS L1 C/A signal. The goal was to assess the impact of EWs on such a modernized signal.

EWFA, static scenario. First, the same Galileo E1 BC signal was generated using two different Navys channels. One was affected by EWFA, and the other was not. The spectra of the obtained signals were observed using a spectrum analyzer. The spectrum of the signal produced by the fault-free channel shows the BOC(1,1) main lobes, around 1 MHz, and the weaker BOC(6,1) main lobes, around 6 MHz. The power spectrum of the signal produced by the EWFA channel has a lag of 5 samples at 120 times f₀ (40 nanoseconds). Again, spikes appear at intervals of f₀, which is consistent with theory. The signal produced by the same channel, but with a lag set to 21 samples (171.07 nanoseconds) was also seen. Such a lag should not be experienced on CBOC(6,1,1/11) signals as this lag is longer than the BOC(6,1) subcarrier half period (81 nanoseconds). This explains the fact that the BOC(6,1) lobes do not appear anymore in the spectrum.

EWFB, static scenario. The same experiments as for EWFA were conducted for EWFB. Fault-free and faulty (EWFB with a resonance frequency of 8 MHz and a damping factor of 7 MHz) signals were simultaneously generated and observed using the spectrum analyzer. The spectrum distortion induced by the EWFB at the E1 frequency was evident. The spectrum is amplified around 8 MHz, which is consistent with the applied failure.

EWFA, dynamic scenario. The same scenario as for the GPS L1 C/A signal was run with the Galileo E1 signal: first, for a period of one minute, a fault-free signal was generated, followed by a period of one minute with the faulty signal. GEMS was switched on and acquired and tracked the two-minute-long signal. Its code-phase measurements, shown in FIGURE 12, reveal a tracking bias of 6.2 meters. This is consistent with theory, where the set lag is equal to 40 nanoseconds (12.0 meters). GEMS-produced ACFs show the distortion of the correlation function in FIGURE 13. The distortion is hard to observe because the applied lag is small.

FIGURE 12. GEMS code-phase measurements on Galileo E1 pilot signal, EWFA dynamic scenario.

FIGURE 13. GEMS ACF computation on Galileo E1 pilot signal, EWFA dynamic scenario.

A modified version of the GPS signal acquisition and tracking Matlab routine was used to acquire and track the Galileo signal. It was configured to accumulate 50 seconds of fault-free signal and 50 seconds of a faulty signal. This operation enables seeing the signal in the time domain, as in FIGURE 14. Accordingly, the following observations can be made:

• The E1 BC CBOC(6,1,1/11) signal is easily recognized from the blue curve (fault-free signal).
• The EWFA effect is also seen on the BOC(1,1) and BOC(6,1) parts. The observed lag is consistent with the scenario (five samples at 120 times f₀ ≈ 0.04 chips).
• The lower part of the BOC(6,1) seems absent from the red signal. Indeed, the application of the distortion divided the duration of these lower parts by a factor of two, and so multiplied their Fourier representation by two. Therefore, the corresponding main lobes should be located around 12 MHz. At the receiver level, the digitization is being performed at 25 MHz; this signal is close to the Shannon frequency and is therefore filtered by the anti-aliasing filter.

FIGURE 14. Fault-free vs EWFA Galileo E1 signal.

The power spectrum densities of the obtained signals were then computed. FIGURE 15 shows the CBOC(6,1,1/11) fault-free signal in blue and the faulty CBOC(6,1,1/11) signal, with the expected spikes separated by 1.023 MHz.

FIGURE 15. Fault-free vs. EWFA Galileo E1 signal power spectrum density.

It is noteworthy that the EWFA has been applied to the entire E1 OS signal, which is B (data component) minus C (pilot component). EWFA could also affect exclusively the data or the pilot channel. Although such an experiment was not conducted during our research, Navys is capable of generating EWFA on the data component, the pilot component, or both.

EWFB, dynamic scenario. In this scenario, after one minute of a fault-free signal, an EWFB, with a resonance frequency of 4 MHz and a damping factor of 2 MHz, was activated. The GEMS code-phase measurements presented in FIGURE 16 show that the EWFB induces a tracking bias of 2.8 meters. As for GPS L1 C/A signals, it is to be noticed that the bias induced by EWFB depends upon the receiver characteristics and more particularly the chip spacing used for tracking.

FIGURE 16. GEMS code-phase measurements on Galileo E1 pilot signal, EWFB dynamic scenario.

The GEMS produced ACFs are represented in FIGURE 17. After one minute, the characteristic EWFB undulations appear on the ACF.

FIGURE 17. GEMS ACF computation on Galileo E1 pilot signal, EWFB dynamic scenario.

In this case, signal accumulation was also performed to observe the impact of EWFB on Galileo E1 BC signals. The corresponding representation in the time domain is provided in FIGURE 18, while the Fourier domain representation is provided in FIGURE 19. From both points of view, the application of EWFB is compliant with theoretical models. The undulations observed on the signal are coherent with the resonance frequency (0.25 MHz ≈ 0.25 chips), and the spectrum also shows the undulations (the red spectrum is raised up around 4 MHz).

FIGURE 18. Fault-free vs EWFB Galileo E1 signal.

FIGURE 19. Fault-free vs. EWFB Galileo E1 signal power spectrum density.

Conclusion

Navys is a multi-constellation GNSS simulator, which allows the generation of all modeled EWF (types A and B) on both GPS and Galileo signals. Indeed, the Navys design makes the EWF application independent of the signal modulation and carrier frequency.

The International Civil Aviation Organization model has been adapted to Galileo signals, and the correct application of the failure modes has been verified through RF simulations. The theoretical effects of EWF types A and B on waveforms, spectra, autocorrelation functions and code-phase measurements have been confirmed through these simulations.

For a given lag value, the tracking biases induced by type A EWF distortions are equal on GPS and Galileo signals, which is consistent with theory.

Eventually, for a given resonance frequency-damping factor combination, the type B EWF distortions induce a tracking bias of about 5.2 meters on GPS L1 C/A measurements and only 2.8 meters on Galileo E1 C measurements. This is mainly due to the fact that the correlator tracking spacing was reduced for Galileo signal tracking (± 0.15 chips instead of ± 0.5 chips). (Additional figures showing oscilloscope and spectrum analyzer screenshots of experimental results are available in the online version of this article.)

Acknowledgments

This article is based on the paper “Generating Evil WaveForms on Galileo Signals using NAVYS” presented at the 6th ESA Workshop on Satellite Navigation Technologies and the European Workshop on GNSS Signals and Signal Processing, Navitec 2012, held in Noordwijk, The Netherlands, December 5–7, 2012.

Manufacturers

In addition to the Navys simulator, the experiments used a Saphyrion sagl GDAS-1 GNSS data acquisition system, a Rohde & Schwarz GmbH & Co. KG RTO1004 digital oscilloscope, and a Rohde & Schwarz FSW26 signal and spectrum analyzer.

MATHIEU RAIMONDI is currently a GNSS systems engineer at Thales Alenia Space France (TAS-F). He received a Ph.D. in signal processing from the University of Toulouse (France) in 2008.

ERIC SENANT is a senior navigation engineer at TAS-F. He graduated from the Ecole Nationale d’Aviation Civile (ENAC), Toulouse, in 1997.

CHARLES FERNET is the technical manager of GNSS system studies in the transmission, payload and receiver group of the navigation engineering department of the TAS-F navigation business unit. He graduated from ENAC in 2000.

RAPHAEL PONS is currently a GNSS systems engineering consultant at Thales Services in France. He graduated as an electronics engineer in 2012 from ENAC.

HANAA AL BITAR is currently a GNSS systems engineer at TAS-F. She graduated as a telecommunications and networks engineer from the Lebanese Engineering School of Beirut in 2002 and received her Ph.D. in radionavigation in 2007 from ENAC, in the field of GNSS receivers.

FRANCISCO AMARILLO FERNANDEZ received his Master’s degree in telecommunication engineering from the Polytechnic University of Madrid. In 2001, he joined the European Space Agency’s technical directorate, and since then he has worked for the Galileo program and leads numerous research activities in the field of GNSS evolution.

MARC WEYER is currently working as the product manager in ELTA, Toulouse, for the GNSS simulator and recorder.

Additional Images

GEMS graphical interface.

Observation of EWF type A on GPS L1 C/A signal with an oscilloscope.

Impact of EWF A on GPS L1 C/A signal spectrum for 0 (green), 41 (black), and 171 (blue) nanosecond lag.

Observation of EWF type A on GPS L1 C/A signal with an oscilloscope.

Impact of EWF B on GPS L1 C/A signal spectrum for fd = 8 MHz and σ = 7 MHz.

Impact of EWF A on Galileo E1 BC signal spectrum for 0 (green), 40 (black), and 171 (blue) nanosecond lag.

Navys hardware equipment – Blackline edition.

Let’s all remember, brevity is the soul of wit.

GPS III Flexible Signal Generator. With completion of the Delta Preliminary Design Review for the GPS III satellites, Lockheed Martin and the U.S. Air Force announced that “an innovative new waveform generator permits the addition of new navigation signals after launch to upgrade the constellation without the need to launch new satellites.”

IGS Real-Time Service. The International GNSS Service, a worldwide federation of agencies involved in high-­precision GNSS applications, announced the launch of its Real-­Time Service (RTS). The RTS is a global-scale GNSS orbit and clock correction service that enables real-time precise point positioning and related applications requiring access to IGS low-latency products. The RTS is offered in beta as a GPS-­only service for the development and testing of applications.

QZSS Will Grow to Four. The Japanese government has ordered three navigation satellites from Mitsubishi Electric Corp. to expand the Quasi-Zenith Satellite System, currently orbiting the sole Michibiki. QZSS augments GPS navigation signals for users in the Asia-Pacific region. NEC Corporation has been awarded a contract for the QZSS ground control segment.

Real-Time PPP with Galileo. Fugro Seastar AS achieved this task within a week of all four Galileo satellites being activated. Fugro is now generating Galileo orbit and clock corrections, which can be used in conjunction with the Fugro G2 decimeter-level corrections associated with its GPS/GLONASS PPP service.

BeiDou Ground System Approved. The BeiDou Ground-Based Enhancement System (BGBES), a network of 30 ground stations, an operating system, and a precision positioning system, was approved by a Chinese government evaluation committee. The system is expected to improve BDS positioning accuracy to 2 centimeters horizontal and 5 centimeters vertical via tri-band real-time precision positioning technology, and to 1.5 meters with single-frequency differential navigation technology.

CNAV Test on GPS L2C and L5. The U.S. Air Force Space Command announced that CNAV capabilities on the GPS L2C and L5 signals will be tested in June. The civilian navigation message to be carried by modernized GPS will have similar data to the existing NAV message, but its structure will be different, with increased message bandwidth for greater information density. L2C and L5 users and receiver manufacturers are encouraged to review the test plan, provide comments, and participate in the evaluation process.

GPS at the Smithsonian. Brad Parkinson’s presentation, “GPS for Humanity — The Stealth Utility,” is now available as video on UStream.The talk helped introduce the new Smithsonian National Air and Space Museum exhibit, “Time and Navigation: The Untold Story of Getting from Here to There,” which is now open and free to the public in Washington, D.C.

While stand-alone portable navigation systems seem to be a fading market driver, connected units seem to be the rage at trade shows and other venues. One example is the recent partnership of Audi of America and T-Mobile USA, who announced a data plan that includes real-time news, weather and fuel prices, Google Earth access and Google Voice Local Search.

The marriage of usually two distinct industries the past three or so years has generated new interest in telematics, which has always been a catch-all term for an automobile’s mobile information features.

While not exactly an eye-opening finding, Berg Insight says sales of PNDs are set to significantly decrease in coming years as consumers choose alternatives. The company says that PND sales will fall to 17 million units, down from the more than 28 million sold last year — and 33 million in 2011.

Berg says PNDs will face stiff competition from lower-cost embedded systems. The company says 150 million people use smartphone navigation apps, compared to 105 million in 2011.

Such companies as Dutch PND manufacturer TomTom said it posted a 13 percent fall, to $262 million, in first-quarter sales. The company is diversifying its product line to counter the loss of revenue from falling PND sales.

To diversify, TomTom rolled out a GPS watch recently to compete with rival Garmin, which has similar products on the market. According to published reports, the company said it is competing with mobile phones for the navigation market.

To echo the Berg findings, TomTom said about 2.1 million navigation units were sold in Europe last year, but in the United States, the drop was even more significant. The company’s PND products fell from 1.5 million units in 2012 to 1.1 million in 2011.

The competition to PNDs is coming from a number of areas. In the recent Audi and T-Mobile deal, users can retrieve information over Wi-Fi for $15 a month (the company says new and existing owners can receive full data services for 30 months for $30 a month). Through the Audi Connect system, users can get connectivity for as many as eight devices.

Audi Connect, which first went on the market in 2011, allows users to gain access to real-time localized weather, news and fuel prices.

Apple Buys Indoor Navigation Company WiFiSLAM

Say what you want about the recent surge in interest of indoor navigation. Some call it an over-hyped fad — or not technically ready for market. The bottom line is that Apple thinks enough of the market to have spent $20 million for Silicon Valley start-up WiFiSLAM in late March.

According to published reports, WiFiSLAM can pinpoint a user’s indoor location to within 8 feet, using Wi-Fi.

Apple has made several inroads to enhance its location portfolio since its Apple Maps debacle in 2012 when users complained about inaccurate directions.

The problems were so acute for Apple Maps that its CEO told potential customers to buy navigation from its rivals, including Waze.

Apple rival Google already has been in the indoor positioning and navigation market, mapping shopping malls, airports and sports venues in several countries.

DeCarta Launches Local Search Engine

DeCarta has launched the L2 Local Search Engine. L2 offers companies the ability to index their own data and make it searchable via a sophisticated single-line search, said Kim Fennell, deCarta president and CEO. Those companies might include local search, vertical search (hotels, restaurants), classifieds, newspapers, Internet yellow pages and others.

“Single-line search is the standard for most web search and for the big mapping portals, but is oddly missing from most local search sites,” Fennell said. “They still use a two-line entry, first specifying what you want and then where you want it. The main reason for that disconnect is that the technology to do good single-line geo-search requires a pretty deep understanding of geospatial data and technology, and is hard to do well. L2 solves that problem. We provide a fully featured local search engine with baseline map and POI data,” he said.

“The local site can clean and index their proprietary data using our tools and then host the search engine in the cloud,” Fennell said. “They get the control of the data and the user interface that the big map portals use.”

Some examples of a deCarta Local Search Engine point of interest entry may be, “coffee near XYZ company,” “restaurants on Main Street,” and “parking near AMC Theater.”

In other LBS news:

• Telenav introduced its embedded product for the Scout for Cars product line. The embedded product features in-dash navigation with mobile and cloud services for real-time, personalized information, the company said. Marketed to automakers, the company said installers can connect Scout for Phones service in their cars for real-time services and personalization. The company said the unit comes with flexible branding so OEMs can offer embedded navigation in their vehicles through their own brands.

• Audiovox’ $169.99 Car Connection kit tracks vehicles and monitors the driver with a built-in GPS unit and a two-way cellular data connection, without a smartphone, the company said. Once an account is established, and the unit is recognized by the Car Connection service, owners can track their cars’ movements and receive e-mail or text alerts in the event the car is stolen or used without permission. An interesting feature is a free app that allows users to find the car via a smartphone. Car Connection costs $10 a month, or $90 per year, and has a $20 activation fee.

Send your LBS news and announcements to Kevin Dennehy at kdennehy@gpsworld.com.

BeiDou. Construction of the second phase of BeiDou has been completed; further launches for the third phase – constellation completion – are on hold until tests of the existing 14-satellite constellation are complete, according to Xiancheng Ding, Senior Advisor, China Satellite Navigation Office. As of December 27, 2012, BeiDou achieved full operational capability for most of the Asia-Pacific region. The full constellation is now expected to be completed by 2020.

Other accomplishments include releasing the BeiDou Interface Control Document and manufacture of BeiDou chips for end-user applications. By the end of June, some manufacturers will release BeiDou chips in China, Ding said.

Also in December, BeiDou introduced a new logo (at right).

Yuanxi Yang (China National Administration of GNSS and Applications) presented statistics showing that BeiDou+GPS provides greater accuracy than GPS alone. For instance, the RMS of BeiDou+GPS kinematic positioning by using differential carrier phase is about 20 percent better than that of GPS alone, Yang said.

By itself, existing BeiDou constellation system accuracy is better than 10 meters, timing better than 20 nanoseconds, and velocity accuracy is better than 0.2 meters/second.

In all, BeiDou is composed of 14 satellites: five GEO, five IGSO, and four MEO. The full constellation (by 2020)  will consist of 35 satellites: 5 GEO and 30 non-GEO (a mixture of MEO and IGSO satellites).

GPS. Keynote speaker David A. Turner (U.S. Department of State) shared his time with surprise GLONASS speaker Sergey Revnivykh (International Committee on GNSS, ICG). In his GNSS Policy and Program Update, Turner provided the dates by which three new civil signals will be on 24 GPS satellites.

• The L2C signal is a developmental signal broadcasting from 10 GPS Satellites. It began launching in 2005 with GPS Block IIR(M) satellites, and is expected to be available on 24 satellites around 2018.
• The L5 signal is a developmental signal broadcasting from three GPS satellites. It began launching in 2010 with Block IIF satellites, and is expected to be available on 24 GPS satellites around 2021.
• The L1C signal begins launching in 2015 with GPS III; available on 24 GPS satellites around 2026.

“We have an increasing number of signals, increasing capability, and increasing level of service as we continue to evolve the constellation,” Turner said.

GLONASS. The next GLONASS satellite will be launched this Friday, April 26, Revnivykh said. This will be a GLONASS-M satellite, number 47. The first launch of a new generation GLONASS K satellite is scheduled for 2015.

Revnivykh stressed GLONASS’ role as a global utility. “We consider international cooperation is essential for all GNSS, and we consider GLONASS an essential part of the international multi-GNSS system,” he said. He stressed the importance of compatibility and interoperability as key to this policy.

In 2012, GLONASS performed with an average accuracy better than formally required, he said. GLONASS is in worldwide use, and positioning has improved by a factor of 10, from 35 meters to about 3 meters since the first satellites were launched. Using both GPS + GLONASS provides 1.5 times better high-precision measurements, Revnivykh said.

The new GLONASS program for 2020 for GLONASS sustainment, development, and use includes GLONASS M, K1, and K2 satellites; the positioning accuracy objective is to go from the current 2.8 meters to 0.6 meters.

Aviation. Chris Hegarty (MITRE) presented an FAA Navigation Programs Overview on behalf of the scheduled speaker Deborah Lawrence (FAA) who was unable to attend. He noted that United Airlines has begun GBAS operations in Houston.

In answer to a funding question, he said, “The sequestration is not expected to have a positive effect on schedule, but the presented timeline for APNT is the FAA’s current best estimate. Congress has some tough decisions before them, and I wouldn’t want to speculate on potential schedule impacts. In the words of Yogi Berra, predicting is hard, especially when it involves the future.”

Korean SBAS. Changdon Kee (Seoul National University) shared plans for a Korean SBAS. In South Korea, LPV availability is 49.4% compared to 90.6% in Japan. “Korea needs its own system,” Kee said.

Phase 3 of the SBAS development could start by the end of September, depending on funding. It will include open service multifunctional GEO satellites interoperable with other SBASs. A pseudolite demonstration system will be completed in 2014, clearing the way for the beginning of Phase 3.

In all, the system will include five reference stations, two master stations, two ground uplink stations, and two GEO satellites (the main GEO by 2018 and a backup by 2020).

The Korean SBAS open service system will provide GPS L1 augmentation, begin operation in 2020, and support aviation, land and maritime users. A test operation system will provide GPS L1 and L5 augmentation. The system is expected to be fully operational by 2021, with service available throughout Asia.

Japan’s QZSS. Hiroyuki Noda (Office of National Space Policy, Japan) said three more satellites for this augmentation system will be launched by the end of the decade, with the service beginning in 2018. In September 2012, the Japan cabinet made the commitment to accelerate development of the system. The first satellite, launched in 2010 (QZS-1, aka Michibiki) is performing as expected.

QZSS is expected to improve positioning availability from 90% to 99.8% in Japan. QZSS will not only improve positioning in the Asia-Pacific region, but is expected to improve the capacity to respond to natural disasters, Noda said.

Launch, deploy, and operate “22 satellites in less than 3 years.” That’s two satellites every three months, leading to a four-at-once launch in 2014. And that’s the challenge that Europe and the European Space Agency (ESA) now face.

This pointed call to action during the opening plenary of the European Navigation Conference (ENC) came from Didier Faivre, director of Galileo Programme and Navigation Related Activities at ESA. It was the only somber note sounded during the keynote speeches, which otherwise paraded the stirring recent accomplishments of the Galileo In-Orbit Validation (IOV) phase. IOV now concludes, and Galileo’s operational phase opens.

The ENC takes place in Vienna, Austria this week (April 23–25), hosted by the Austrian Institute of Navigation. Privately and informally, a handful of knowledgeable conference attendees expressed confidence that OHB System can furnish the completed satellites, at least, according to schedule. OHB System is the prime contractor for  construction of 22 Full Operational Capability (FOC) Galileo satellites and is responsible for developing the satellite bus and for integrating the satellites. Surrey Satellite Technology Ltd. (SSTL) is developing and constructing the navigation payload and  assisting OHB with final satellite assembly.

“Using only European tools and means, European ground infrastructure deployed on European territory, our conception, machine and design, is totally validated,” stated Faivre, referring to the recent Galileo-only positioning fix by ESA. The March 12, 2013, event marks “the end of the beginning,” and culminates 12 years of intense work at all levels of European industry.

“Europe is at par with GPS” with performance as expected. “I hope that soon our U.S. colleagues will be jealous of our performance,” Faivre stated, implying yet again the persistent Galileo claim that the system will be more accurate than GPS. He returned to this theme with reference to Fugro’s accomplishment of real-time precise point positioning at the centimeter level.

He acknowledged that “It’s a technological competition with the United States, Russia, and China,” even though all may be friendly and collegial.

In that competitive light, “the success of Galileo will be measured by the number of users,” and not by the number of satellites, or the degree of accuracy, or the strength of the signal.

Previously, the ENC audience had heard from Ingolf Schädler that “Europe has closed the gap with the technological superpowers,” in what “may be the most complex invention ever of mankind, the system of navigation that is GNSS.” He also made a proud reference to Austrian-produced signal generators aboard Galileo’s orbiting IOV satellites. Schädler is the deputy director general of innovation for the Austrian federal Ministry for Transport, Innovation and Technology.

“We have reached cruising speed,” announced the third keynote speaker, Carlo des Dorides of the European GNSS Agency (GSA). He was referring explicitly to the re-positioning of the GSA headquarters from Brussels to Prague, but the remarks reverberated to the Galileo program as a whole.

David Blanchard, deputy head of unit, EU Satellite Navigation Programmes for the European Commission, quoted an unnamed U.S. publication: “With the capability to make a position fix from four signal-broadcasting satellites, we can now say that Galileo has truly arrived.”

That statement appeared in the May 2013 GPS World, an issue of the magazine that was distributed in conference bags to all attendees at the ENC.

Blanchard then shifted the focus slightly from Galileo, to Galileo together with the European Geostationary Navigation Overlay Service (EGNOS), Europe’s satellite-based augmentation service that also broadcasts GPS corrections. “We have to make sure that all the capabilities afforded by EGNOS are realized.” He also made strong references to the EGNOS Data Access Service (EDAS).

Blanchard cited a current ongoing study that shows that 6 to 7 percent of European gross domestic product (GDP) is dependent upon GNSS.

“A gold mine within arm’s reach of European industry” was how Gard Ueland, head of Galileo Services, characterized the present situation. “Development of European downstream market is crucial; it also has to bring more benefits to European society.” Galileo Services will host a workshop of  industry stakeholders in late October, at the OHB System premises in Bremen, Germany. Watch GPS World Events calendar and news for an announcement with specific dates.

Having attained altitude and cruising speed, the Galileo program must now shift to warp speed to hit its goals on time: 18 satellites in orbit by the end of 2014, and a total of 26 by the end of 2015. Early services by the end of 2014, and full services in 2016. Stable, continuous services, as Blanchard emphasized.

Better go to overdrive.

Indoor location research and fielded developments currently focus on consumer-level applications, mostly using mobile phone handsets, but this work will hopefully also benefit professional and high-precision uses of GNSS. Indoor location technologies could be of particular interest in machine control for warehousing, industrial assembly, indoor and even underground mapping, underground mining, in forestry where dense canopy virtually cuts out GNSS, construction, and other areas where sky-view is limited or negligible.

Tune in to Indoor Nav Webinar Thursday

Tune in to GPS World’s webinar, “Indoor Positioning and Navigation: Results of the FCC’s CSRIC Bay Area Trials,” on Thursday, April 18. Speakers include Khaled Dessouky (Technocom); Ganesh Pattabiraman (NextNav); Norm Shaw (Polaris Wireless); and Greg Turetzky (CSR). Registration is free.

Professional users will want to keep abreast of developments in the E-911 area, and be aware as achievable accuracies begin to approach what could be possible for precision applications. Right now, that’s maybe a pretty big stretch, but taking a look periodically is a good idea. A recent round of landmark tests by the Federal Communications Commission (FCC) provides just such an occasion for a look-in.

The U.S., E-911 legislation put in place back in 2001 required that both landlines and cellphones should provide the location of callers to within specific accuracy levels. Location information was to be sent transparently to Public Safety Answering Points (PSAPs) which would allow fire/rescue/police personnel to be dispatched to the location of the 911 call. For mobile phones, cellphone manufacturers and network providers forged ahead and implemented a number of location strategies using differing technologies — all require being outdoors where a clear sky-view is available.

GPS and augmented GPS technologies were only part of the cellphone solution. Other implementations included use of the cell-signal itself, along with an extensive database that can contain, amongst other things, signal attributes and network asset locations. Turns out that, today, around 60 percent of mobile phone calls are made within buildings, so the FCC started to investigate how to bring E-911 capability to indoor calls.

In 2011, the FCC commissioned a group called the Communications Security, Reliability and Interoperability Council (CSRIC), and Working Group 3 (WG-3) is the one currently investigating what can be done for indoor E-911 location. Drawn from interested industry participants, the WG-3 Location-Based Services (LBS) sub-group set about finding what technologies exist, how well they work, and how they could be applied to E-911. Now, there are a lot of people trying to crack this problem and many, many ways that it’s been tackled — all of which are at different stages of development and with differing levels of capability. In order to make definitive progress, WG-3 LBS decided that a test-bed was the best way to evaluate and compare what’s currently available.

Seven vendors signed up initially, but only three — NextNav, Polaris Wireless, and Qualcomm — completed the rigorous testing, which set out to basically establish horizontal and vertical accuracy, speed of location, and reliability and consistency of results for each system. The trial tested the performance of location systems across urban, suburban and rural areas in the San Francisco Bay Area. More than 13,000 test calls were placed from various tested technologies in 75 different indoor locations selected by participating public safety organizations from around the U.S. Click here for the full report.

In the tests, Polaris Wireless used an RF pattern matching/fingerprinting technique, Qualcomm used a hybrid Assisted-GPS (A-GPS)/Advanced Forward Link Trilateration (AFLT) system, and NextNav used wireless beacon technology. NextNav came out on top, and largely within the magical 50-meter “search ring” requirement, and was the only vendor to provide vertical location capability.

NextNav uses pressure transducers in its beacons and in the handheld units to accurately measure calibrated altitude — within about 2 meters — so it can actually report the floor where the handheld is located; it’s the only system tested that was able to do so. Apparently the use of MEMS pressure sensors in cellphones is forecast to increase to 681 million units in 2016, so this could be the right approach.

NextNav is focusing on the San Francisco market, where the company has fielded a significant number of beacons, but it has also placed beacons in another 40 metropolitan locations across the U.S. NextNav has acquired appropriate spectrum rights to transmit a 900-MHz “GPS-like” signal that’s synchronized to GPS. This enables good penetration into most urban buildings — both high-rise and those with fewer floors.

To support adoption of its solution, NextNav is working with a chipset manufacturer to incorporate processing of its location signal within an upcoming spin of an embedded cellphone chipset. While other solutions have adopted Wi-Fi and cell-signal solutions, NextNav contends that its approach is the most cost effective, as beacon deployment is geographically less dense and can be amortized over so many users.

NextNav Beacon.

Other solutions also apparently rely on the use of databases that store signal characteristics and a number of other parameters – the CSRIC report highlights the complexity this brings to database management and maintenance. NextNav also has a database, but this is basically to store records of location, cable configurations and calibration data. This is only used to ensure consistent performance of their system; it’s not required for network operation or location.

Higher precision applications would also benefit from this type of augmentation in the same way that WAAS users achieve higher accuracies, except this system uses local beacons, and there could be the potential for even higher precision with known fixed beacon locations within urban environments. As commercial UAV applications grow, it’s not impossible that there will be higher precision flight applications within cities, for geo-location surveying, building and outside appliance inspections, signal mapping, traffic mapping, road-work repair monitoring — in fact, many of the monitoring activities we see daily in towns and cities where a view of the sky can be particularly restricted.

The CSRIC participants are not the only ones pursuing the holy grail of indoor location. As mentioned, seven different location vendors/technologies began the process to demonstrate their performance indoors through the common test bed, but only three completed the process. The others remain highly motivated and involved, however, and at work tuning their varied solutions. The WG3 report states, “The following location vendors showed initial interest in having their technologies tested and highlighted through the test bed process, but ended up not participating in the Stage 1 test bed, for a variety of reasons.

• U-TDOA Positioning (TruePosition)
• DAS Proximity-based Positioning (CommScope)
• A-GNSS / Wi-Fi / MEMS Sensor Hybrid Positioning (CSR)
• LEO Iridium Satellite-based Positioning (Boeing BTL).”

Meanwhile, promising indoor location research goes on at a number of commercial and academic institutions, such as the University of Calgary PLAN group, which has focused on integration of Wi-Fi and GPS. An upcoming paper reports that Wi-Fi, using the 802.11 standards, can be employed in several different ways as a complementary positioning technology for GPS/GNSS navigation, and the two can be used in an integrated framework to provide a continuous and robust positioning service.

Another promising component for indoor location could be the recent release of a software application by Baseband Technologies, which can provide rapid ephemeris for up to 28 days, between ephemeris downloads from GPS directly or over cellphones from the Internet. But indoor location warrants much more extensive treatment than these few random comments — what’s summarized here are only some recent developments in E-911.

There will likely be another round of E-911 test-bed activities if funding and management issues are resolved. See CSRIC WG-3 LBS Subgroup member Greg Turetzky’s “Expert Advice” column from GPS World for perspective and a forward look. We can anticipate even wider participation by differing technologies and even greater levels of performance in future. Longer term progression towards higher precision professional applications seems to be inevitable.

Tony Murfin,
GNSS Aerospace