When I arrived in Denver, my plan was to meet Tim Smith (GPS Coordinator for the U.S. National Park Service) and travel to the Bakerville GPS test site in the Rocky Mountains, which was at about ~11,000 feet in elevation. My intent was to test the CORS Streaming and PBO real-time streaming that I discussed last month to better understand the accuracy and reliability of those services.

I arrived at the Denver airport early on a Monday ready to rock and roll into the Rockies with some high-precision GNSS equipment. As it turned out, I was denied. In Colorado, the weather is dynamic. It was quickly degrading when I arrived in Denver. Snow was definitely in my future for the next few days. Tim made the decision that we shouldn’t travel to Bakerville. The reason for Tim’s trepidation wasn’t necessarily due to the weather in Bakerville, but rather that the I-70 Interstate might turn into a parking lot and we’d be stuck in traffic for a few hours. Fair enough. The backup plan was to do some local testing in the parking lot adjacent to Tim’s office in Denver.

Tim invited Mel Philbrook to join us. Mel is a long-time GNSS technologist who works for the local Trimble dealer. He brought an SUV full of Trimble GNSS equipment, including one of the new R10 GNSS units as well as a GeoXH handheld with an external antenna.

Tim Smith using a Trimble R10 with CORS Streaming RTK data.

Mel and Eric with some of the GNSS gear.

Mel also had an Intuicom RTK Bridge in the trunk of his SUV that facilitated the different sources of RTK reference data we could use. He could switch from CORS Streaming to the local VRS via NTRIP to UHF at the flip of a switch, sending corrections to both the R10 and the GeoXH. I was particularly interested in seeing how the units performed using CORS Streaming, which is/was a free RTK service (single baseline) that was in beta test phase. In Oregon, I don’t have access to CORS Streaming because the only CORS Streaming station west of the Mississippi River is in Boulder, Colorado. The station is TMGO (Table Mountain CORS).

The baseline distance from TMGO to our location was about 55 km. The R10 was reporting a horizontal precision of about 4 cm. Not bad for a 55-km baseline. I didn’t compare the results to a survey mark (shame on me, but keep reading because I get to that) so I’m trusting the R10’s precision estimate. Tim said he’s run the test before using a GeoXH and a longer baseline and saw sub 10-cm horizontal precision. It’s not what the typical person using short baseline or RTK network is accustomed to, but for the high-precision GIS user who’s mapping utility, transportation, and infrastructure, that’s pretty darn good.

Tim, Mel and I spent an hour or so messing around with the equipment before packing it up. Not a very scientific study, but it confirmed that CORS Streaming was accessible via NTRIP and reasonably accurate.

In the meantime, the snow wasn’t letting up. This is the view as I was leaving Tim’s office to head to Boulder for the Space Weather Workshop:

Leaving Tim’s office. There was no snow when I arrived.

I wasn’t finished with my CORS Streaming testing yet. My experience at Tim’s office gave me enough confidence to allocate time later in the week to conduct a more detailed test after the Space Weather Workshop. Hopefully, the weather would cooperate (call me a fair-weather field guy).

Space Weather Workshop

Every April, NOAA’s Space Weather Prediction Center in Boulder hosts the Space Weather Workshop (SWW), a gathering that has evolved into the leading conference in the U.S. for space weather-related topics. It attracts attendees, experts and speakers from all over the world. The discussion isn’t centered on GNSS, but GNSS certainly is a topic that is discussed. This year’s central topic was the electric power grid. You can view the SWW program here.

Believe it or not, this month (May 2013) was the predicted “solar maximum” for the current solar cycle (Solar Cycle 24, an 11-year cycle). However, Solar Cycle 24 has been unexpectedly weak. See the following slide presented by Doug Bisecker of the Space Weather Prediction Center. Doug is the Chairman of the Solar Cycle 24 Prediction Panel. His question, “Is there any chance we can still salvage some respectability?” speaks volumes about the difficulty in predicting space weather.

Source: Doug Bisecker presentation at the 2013 Space Weather Workshop

From the above, you can see the actual number of sun spot occurrence has been significantly less than predicted. Although sun spots aren’t what cause GNSS receivers to have problems, sun spots can indicate the amount of solar activity, which can be related to geomagnetic storms. Geomagnetic storms disturb the ionosphere and are the events that cause the most problems for GNSS receivers. Looking at the top chart above, you can see the difference in activity between the last solar maximum (peaked in early 2002) and today. The difference is clearly significant.

Does this mean we, the high-precision GNSS users, get a free pass on Solar Cycle 24?

Not at all.

Historically speaking, the most extreme geomagnetic storms (e.g., Oct/Nov 2002) have occurred after the solar maximum so our sensitivity to this issue should be keen for the next two years. Furthermore, there are orders of magnitude more high-precision GNSS receivers being used than ever before, and in mission-critical applications such as auto-steer in machine control (agriculture, construction, etc.). Most GNSS high-precision users today haven’t experienced the effects of an extreme geomagnetic storm. For a short primer on the effects of solar activity on GNSS/GPS, you might want to take a look at this article I wrote in 2008 as well Richard Langley’s 2011 Innovation column “GNSS and the Ionosphere.” In addition to the content, they both contain some valuable links to relevant articles.

In line with a goal of the workshop, a panel of GNSS professionals looked at issues that users face as they go about their business at solar max. The panel was “Global Navigation Satellite System (GNSS) Services: Research Needed to Fill Operational Gaps.” Joe Kunches (SWPC) moderated the panel that included Dr. Geoff Crowley (Astra), Dr. Anthea Coster (MIT), Capt. Steven Miller (USAF) and myself. We highlighted precision GNSS, satellite navigation for commercial aviation (ADS-B), and current work to better understand the errors the ionosphere imposes on user activities.

Something else I learned at the conference was how tough ionospheric scintillation is on GNSS receivers in Brazil. I feel for those users. When I mentioned I was traveling to Chile for an RTK project, the scientists said it is worse in Chile than the U.S., but still not as bad as Brazil. I’ll be very interested to experience how different it is than the U.S. (or other parts of the world where I’ve traveled).

I keep a pretty close eye on space weather and in contact with NOAA’s Space Weather Prediction Center. When I hear of a space weather event that may affect high-precision GNSS/GPS receivers, I send out a Tweet with the hashtag #SolarActivity. You can follow me on Twitter at https://twitter.com/GPSGIS_Eric.

From Space Weather Back to Local Weather

As the week progressed during the Space Weather Workshop, the snow continued. Boulder looked like Christmas in April.

Christmas in April, Boulder, Colorado.

I really wanted to spend some more time in the field to test the accuracy of the NGS’s CORS Streaming service and I was running out of time. In order to perform the test the way I wanted, I needed to find a local NGS survey mark that was observed using GPS. I checked out the NGS survey mark database and got lucky. There was one (PID = KK2060) located on a vista point parking area off of Highway 36 on the way from my hotel to the Space Weather Workshop. I couldn’t have asked for a better or more convenient survey mark location. I was planning to use a Bluetooth GNSS receiver so I could actually collect data while sitting in my car.

KK2060 Survey Mark along Highway 36

On Thursday morning, Mother Nature cleared her skies for me so I drove to the vista point. Remember, there’s a couple of feet of snow on the ground, so I was really hoping to see some kind of wood lathe that would get me close to the survey mark (no, I didn’t preload the KK2060 coords in my GPS L). Fortunately, a wood stake was near the survey mark. However, I didn’t have a shovel or a metal detector so it was either using my hands to shovel and search under two feet of snow for the mark, or…thanks to the rental car company, the car came with a healthy-sized windshield scraper. After 15 minutes of digging in the snow with a windshield scraper, I found KK2060. I’m sure to the people parked on the vista enjoying the view; I looked very suspicious using a windshield scraper to dig a hole in the snow. I wouldn’t have been surprised if a state trooper had shown up.

KK2060 recovered from under two feet of snow with a windshield scraper.

My final challenge was…no tripod or tribrach. I travel light and didn’t want to pack a set and, of course, I forgot to ask Tim if I could borrow a set. It’s never a good idea to set a GNSS antenna directly on the ground, but the antenna was small (<3” in diameter) and I did have a 5” diameter ground plane with about a 1” post. I was able to place it over the survey mark with reasonable confidence.

3″ diameter L1/L2/GLONASS antenna on a 5″ ground plane centered over KK2060.

As I mentioned before, I was using a Bluetooth GNSS receiver (GPS L1/L2, GLONASS), the SXBlue III GNSS.

SXBlue III GNSS bluetooth receiver

To collect the data, I was using an SXPad handheld with an AT&T SIM card for the Internet connection. For data-collection software, I used VisualGPSce, a free GPS data-collection program that collects and displays raw NMEA data. Although it doesn’t display enough digits of precision for the horizontal position, it accomplishes the simple task of collecting NMEA-formatted data without applying any transformation so I get the raw NMEA-formatted data from the receiver. It also displays some useful information such as PDOP, RTK indicator and elevation.

VisualGPSce running on an SXPad data collector collecting RTK data.

The last piece of data-collection software I used was a free NTRIP client software written by the SXBlue people called SXBlue RTN. I needed an NTRIP client software to access the CORS Streaming mount point. The software manages the IP address, port and login/pwd of the CORS Streaming system.

Logging into the NGS CORS Streaming site was painless, and within a few seconds I had an RTK FIXed position from the GNSS receiver, all from the comfort of my rental car, thanks to long-range Bluetooth. I collected ~45 minutes of NMEA data (1-Hz data rate) without interruption.

When I returned to the office, I began the process of comparing the results from CORS Streaming to the NGS survey mark coordinate. I checked with NGS and they reported that CORS Streaming is referenced to the ITRF00 (epoch 1997.0) datum. The KK2060 coordinate is published in NAD83/2011 (epoch 2010.0). I needed to reconcile the datum difference before performing any analysis so I used the NGS HTDP (Horizontal Time Dependent Positioning) online tool to accomplish this.

Finally, I used NMEA Analyzer (custom-built software for performing statistical analysis on GNSS NMEA data to NSSDA horizontal accuracy standards) to calculate accuracy (not precision) values of the data. I set up the NMEA Analyzer software to randomly select 200 epochs out of the ~2,700 collected to mitigate any bias due to filtering or other receiver “tricks”. Following are the horizontal results:

Not bad for an antenna sitting on the ground and an 18-km baseline using a $6,000 GNSS receiver and a free RTK base station. Folks, this is the direction that GNSS technology is heading. The continued proliferation of high-precision GNSS infrastructure (RTK networks, real-time PPP, etc.) and the falling prices of RTK GNSS receivers will dramatically increase the availability of high-precision technology to those who previously could not afford to make the investment.

I didn’t get a chance to test the PBO real-time streaming while I was in Colorado, but fortunately there are many PBO real-time stations that I can test from the comfort of my home office here in Oregon. In fact, there are so many in Oregon and Washington that I can test many different baseline distances to understand what accuracy users can expect. Look for my test results on that sometime this summer.

National Geodetic Survey (NGS) Suffering

It’s likely that you aren’t an NDGPS user, but you might still be affected if the NDGPS is decommissioned. There are a total of 86 NDGPS stations across the Continental U.S., Alaska and Hawaii. As well as being NDGPS signal broadcasters, they are also part of the NGS CORS program that is used by the NGS’s OPUS online post-processing service. If you are using OPUS or NGS CORS for post-processing, you might be using NDGPS CORS data and not realize it. Following is a map of all NDGPS stations in the U.S.:

U.S. NDGPS coverage map.

If you’re interested in reading an explanation from the U.S. Coast Guard and Department of Transportation about the request for public comment and submitting a comment, click here. To be considered, comments must be submitted by July 15.

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

James D. Litton

By James D. Litton

The sixth annual Stanford PNT Symposium in November brought together a select group of experts to share insights from the latest research, developments, and proposals, GNSS and non-GNSS, that show promise for the international community. Among other noteworthy presentations, we heard Brad Parkinson’s suggested incremental system changes to significantly improve signal availability and accuracy, a comprehensive update on China’s Compass system, and the latest in spoofing and proposed proofs of location.

GNSS in General

The budget realities of U.S. GNSS development, and the need to maintain the systems at the high levels of performance upon which so many critical and commercially beneficial applications now depend, were analyzed by two men with industry-household names, Brad Parkinson and Gaylord Green.

Nibbles. Professor Parkinson gave a very sophisticated, nuanced presentation entitled “Nibbles,” in which he outlined feasible and productive technical steps to ensure the preservation of what he described as “the three As:” availability, affordability, and accuracy. Rather than do radical surgery on accuracy or availability in order to preserve affordability, he identified so-called nibbles at requirements, incremental improvements enabled by use of current technology advances, for example, vector (Spilker) receivers, power-conversion efficiency improvements, antenna gain and steering modifications, weight reduction for multiple launch capability, and use of sensor fusion for more robust receivers with greater jam resistance.

It was a high-level but quantitative system design approach aimed at improving affordability and interference resistance while maintaining and improving availability and accuracy. He made the salient point that affordability with a given level of performance is enhanced by availability, that is, maintaining 30+ satellites on orbit brings multiple benefits that improve affordability. The estimates of gain from the nibbles struck me as conservative, at least for those with which I had some quantitative feel.

Alternative Architectures. Col. Gaylord Green addressed the same subject with a different approach, in a presentation entitled “GPS Alternative Architectures.” His motivation for alternative architectures was to provide the needed PNT capability at an affordable cost. He pointed out that GPS satellites have increased in dry weight from 334 to 2,100 pounds, and that the cost of the IIA, IIF, and III satellites have gone from $100 million on orbit to $400 million on orbit. Colonel Green indicated that starting a new development with the same signals cost more than continuing with GPSIII. (The Congressional Budget Office has recommended consideration of using IIF satellites to maintain the constellation and bypassing GPS III.)

The reduced capability satellites are called NavSats. He suggested that a mixed constellation of NavSats (with minimal ancillary payloads and frequencies) such as 15 GPSIII and 15 NavSats would enable a constellation of 30 satellites; the minimum necessary to assure sky-challenged users of satisfactory coverage. He recommended that design of satellite power conversion to be set by start-of-life, not end-of-life goals. Colonel Green identified the signal priorities in terms of their functions (L-5, L-2, L1C, and four military signals requiring crypto). Like Parkinson, he identified technology changes in antennas and signal architecture to reduce costs, necessitating a demonstration program. He also indicated that advantage could be taken of other GNSS constellations for civil signal purposes, alleviating the demands on GPS satellites. Colonel Green identified satellite constellation arrangements which would be more cost effective (multiple launch) and provide adequate coverage. He pointed out that such a NavSat program would require a new start and would necessarily constrain GPS modernization funding. In short, such a “GPS Alternative Architecture approach” would combine continuation of GPS III as planned with the addition of simpler, lighter satellites with reduced diversity of signals to replace the aging GPS satellites now on orbit beyond their design life.

Compass. Professor Jingnan Liu of the GNSS Research Center of Wuhan University gave what most observers thought was the first comprehensive and data-intensive description of Precise Positioning results with the COMPASS (Beidou) system. He showed that the Beidou regional system, from which he presented copious data, can currently provide standard positioning service with <10M horizontal and <20M vertical accuracies at 95% confidence level. He also showed that results with Beidou plus GPS are 10-20% better than GPS alone. He provided results for surveying, for ground-based augmentation, for RTK, PPP, clock stability, orbital statistics, wide area differential and many other metrics of PNT. Professor Parkinson noted, in appreciating the presentation, that it was the first detailed release of so much technical data on COMPASS performance. The results noted above were obtained with 4GEO+5 IGSO+2MEO satellites. The constellation is expected to grow to 5GEO+5IGSO+4MEOs by the end of 2012 and to 5GEOs+3IGSOs+27 MEOs by 2020 for a global service. The amount of data and the diversity (application and instrumentation) of the data were truly impressive.

GPS Modernization. Dr. Keoki Jackson of Lockheed Martin presented a comprehensive review of GPS Modernization with charts which described the evolution of GPS from Block I to Block III. He depicted the program as on schedule for delivery of the first GPS III vehicle in May, 2014, with a 2015 launch. Most of this material was the same as reported from the AFCEA GC-12 program in GPS World earlier this year. A matrix comparing the attributes of GPS III with GPSII and beneficial outcomes from “Back-to-Basics Investments” were key takeaways.

Ground Control. Ray Kolibaba of Raytheon presented a detailed overview of the OCX program, the next generation Operational Control System. This presentation also emphasized improvements in program management, simplification of development practices, extensive use of commercial development methods and predicted on-time delivery with all of the attributes needed for both GPS III and the existing constellation.

Military User Equipment. Col. Bernie Gruber, Director of the GPS Directorate, gave an update on current activities with emphasis on progress in Military User Equipment (MGUE) development. This material was somewhat further advanced in schedule than the equivalent May 2012 time frame in which the same subject was presented in much detail at the AFCEA GC-12 meeting at the Directorate. The currently ‘hot’ topics of jamming and spoofing threats, countermeasures and affordability were prominent in the presentation. Some of the key achievements for 2012 listed were the release of BAAs (Broad Agency Announcements) for NavSat studies and the completion of a Congressional Report on ‘Cost Effective GPS). Launch of GPS IIF-3 and delivery of GPS IIF-4, 5,6 & 7 were also noted. Security Certification for MUE cards was a very noteworthy achievement, which will make future MGUE development and utilization much easier for the challenging jamming and spoofing environment which is expected. The themes of affordability and jamming and spoofing threats were dominant in this review, as well.

General PNT

Norvald Kjerstad is a professor of Nautical Science at Aalesund University College and a long-time professional navigator in academic, geophysical, and shipping communities. His paper vividly depicted the risks brought about by climate change, by increased commercial interest in shipping and mineral resource exploration in the Arctic region, and by the very limited navigation infrastructure and limited communications assets.

Arctic Navigation. Both DGPS and SBAS systems are quite limited in the arctic, magnetic compass systems are less accurateat the very high latitudes ( and their errors propagate into navigation radar, collision avoidance and other systems). Auroral effects limit the availability of GNSS at times (Glonass improves GPS because of the higher orbital inclinations) and hydrographic charts of the arctic are frequently quite wrong, due to changes in water depth and to limited surveying frequency. Increased tourism, shipping and resource interest intensify the consequences of the increased risk to seafarers.

The advent of Galileo and Compass, integrated with GPS-Glonass will greatly improve the reliability of GNSS signals. However, navigation through the ice, at places thin and navigable and at random places deep and massive (ice ridges) is much more than knowing where one is with respect to the center of the earth. Radar helps with detection and avoidance of ice ridges but the sinking and grounding of icebreakers and commercial vessels demonstrate that much better knowledge of the environment is needed to avoid future disasters. The thousand-kilometer shorter route over the Pole can be very expensive and not necessarily the fastest one. However the increased activity in the Arctic is going to continue, and it is mandatory that safety factors be given greater attention by the International Maritime Organization (satellite compasses are reliable where magnetic ones are not, but the IMO has not approved them) and by the hydrographic services of the affected areas.

From Farm to Front Office. Jim Geringer, former governor of Wyoming, now a director of ESRI and a member of the GPS Excom gave, as usual, a very entertaining presentation (“GPS/GNSS From the Farm to the Front Office”) with highly interesting examples of the very broad and deep impact of GNSS on society, including financial statistics and object lessons in the misuse or inaccurate use of geospatial data. Geringer was an engineer before he went into politics and that came through clearly in the presentations, even though he was very self-effacing concerning his technical credentials. He gave amusing examples, not all from Apple, of the effects of combining current and historical geospatial data, such as airport runways shown in topography layers obtained before leveling the airport areas, and a road running across the valley filled by Hoover Dam.

Geringer critiqued an attitude on the part of GNSS professionals in which their attention is more devoted to the how of obtaining the information than to the effects that future changes might have on the users. He discussed policy challenges presented by the FCC mandate to find 500MHz of spectrum for high speed wireless data, by affordability, by the potential for jamming and spoofing. It was good to be reminded of the awesome realized economic benefits of GNSS, the manifold applications which GNSS systems enable and the ease with which this potential can be limited or actually damaged by pursuit of other worthwhile objectives which are politically favored or which bring short term revenue into the treasury at the expense of GNSS system requirements in bandwidth. The less obvious but equally or more beneficial economic benefits of high accuracy GNSS and the impact of actual lives lost or resources untappedwere illustratedand quantified in Geringer’s broad presentation. One hopes that this presentation will be or has been seen at High GSA and policy levels in the FCC and NTIA.

Geringer’s presentation provides a nice segue into a presentation by:

LightSquared Lessons Learned. Rich Lee of Greenwood Telecommunications Consultants, LLC and iPosi.  Entitled Lessons Learned from the GPS-LightSquared Proceeding, it was an assessment of the opportunities missed and damage done in the drive to enable the use of spectrum adjacent to GNSS frequencies for 4G LTE wholesale services through high power Auxiliary Terrestrial Components (ATCs) using MSS spectrum reallocated (or repurposed) to the purpose under a conditional waiver by the Chairman of the FCC, Julius Genachowski, on a recommendation by the International Bureau of the FCC. According to Lee, Greenwood was called in to solve, “if solutions exist” the problem of the ‘spectrum collision’ between the LSQ design and GPS, after the collision occurred. He likened the role of Greenwood to that of a tow truck operator called in to clear up a collision after the impacts. Lee served on the TWG (Temporary Working Group) as head of the cellular subgroup and headed the NTIA/Excom cellular tests. The presentation was very good, technically, in both its detailed and more strategic aspects but both the history described and the lessons learned (see below) were, understandably, from the perspective of a party which was unable, in this particular instance, to achieve the goals desired by their sponsors. This failure was for reasons of basic spectrum policy conflicts between GNSS applications and those mooted to become transcendent- mobile high speed data for consumer and industrial applications.

Lee depicted the lack of a requirement in history for regulation of receiver standards, as opposed to transmitter standards, to the inability to anticipate the crowded spectrum (for example, his statement that spectrum was regarded as “free” and minimizing interference was the key objective, a burden placed on the transmitters). Now that spectrum is seen as scarce and underutilized in many U.S. government applications and inadequately conserved in many civil applications, the concept of receiver standards for avoiding interference and the use of advanced filterand antenna technology in receivers as well as in transmitterswould enable easier, less confrontational and more lucrative use of this 21st century El Dorado.

Parenthetically, Pierre de Vries (University of Colorado, and a member of the FCC’s Technical Advisory Committee) and others recently testified to a House of Representatives panel, recommending that harm claim thresholds be established with which to manage the trade-offs between intrinsic receiver protection requirements and transmitter power distribution, so that instead of just adding the specification requirement to receivers, a flexible system approach be adopted. They noted that it was very difficult to anticipate the receiver design needs for all applications. The failure to understand the requirements of precision GNSS receivers and the simplistic concept of fences was a large driver in the collision between LightSquared and GNSS.

Lee’s lessons learned summary is:

• Upper 10: candidate for ground augmentation? The upper 10 MHz (1545-1555 MHz) of spectrum was originally allocated to LightSquared through its acquisition of TerraSat. During the 2012 conflict months, LightSquared publicly abandoned operating in the Upper 10.
• Question: sound alternatives for this band? (Including as a good GNSS guard band)
• Consider: sub-microwatt uses for short range augmentation, such as Department of Transportation Intelligent Transport Systems (ITS)-TWG findings. Given very low effective isotropically radiated power (EIRP), ample compatibility with precision GPS nearby.
• Precision GPS: –82 dBm worst case Upper 10 susceptibility (–1 dB C/NO)
• 1 uW EIRP transmitter is about 13 dB below at 1 meter
• Seems suitable for high availability in urban areas; provides urban in-fill, redundancy such as ITS
• At 100-mETER range: Signals ~-135 dBm incident power at an ITS receiver antenna
• Band continues as a space-to-earth downlink, shared with geostationary Earth orbit-mobile satellite services, including carriage of GPS/GNSS corrections (OmniSTAR, StarFire)

Lee contested the FCC chairman’s assertion that the LightSquared-GPS matter was an anomaly, saying instead that it was “foreseeable.”
However, foreseeable anomalies such as singularities exist in predictions of scientists. I believe that this anomaly was clearly foreseeable, but a hedge-fund mentality, financial engineering, and a long-held attitude toward GPS in the FCC were the drivers of these benighted decisions.

The gold rush is still on for finding underutilized spectrum. Some systems, including GNSS, utilize bandwidth that needs protection for purposes other than the usual communications requirements. It is vital to honor the homesteads of GNSS and protect the noise floors. Receiver standards must be considered very carefully because communications receivers and high precision GNSS receivers are very different systems.

Scientific Subjects

Some presentations grouped under this topic are available in ION publications from GNSS 2012.

Atom Interferometry. Mark Kasevich of Stanford presented his paper on precision navigation sensors based upon atom interferometry. While application of these sensors in general awaits many highly difficult engineering advancements, the outcome would be a great boon to navigation, were the outcome comparable to the evolution of chip-scale atomic clocks.

Andrei Shkel reprised his paper entitled “Precision Navigation, Timing, and Targeting enabled by Microtechnology: Are we there yet?”

Gravity. Tom Murphy of the University of California, San Diego, gave a fascinating paper of fundamental importance to understanding gravity by laser ranging to retroreflectors left on the moon by various Apollo and Russian missions. A highly contrived initialism for the project is APOLLO, for Apache Point Laser Observatory Lunar Laser-Ranging Operation. The work is a product of a seven-university/research center consortium.

The system of APOLLO for measuring the range of the moon relative to the earth at Apache Point is a marvel of experimental ingenuity and advanced instrumentation in collecting the few photons that get back from the laser shots at the moon. Laser light is caught by the retroreflectors and returned to the telescope at Apache Point. A very sensitive gravimeter system at the observatory enables compensation for the Earth’s crustal motions, and orbital deviations are compensated. Precisions of a few millimeters in range to these devices on the moon are achieved, almost good enough to be useful in testing the “Strong” Equivalence Principle of General Relativity.

From an engineering point of view, the timing, motion compensation, detection sensitivity (a few photons per shot), and several other features of the system are truly impressive, and the potential for improving our understanding of general relativity, so-called dark matter or energy, and more, are exciting aspects of this work. To have much better precision through placing laser transceivers on the moon to increase the number of reflected/transponder photons in the samples would appear to be quite valuable and relatively simple NASA missions for future work, even though the data may eventually be sufficient to enable theoretical advancements without such added signal-to-noise benefit. This paper was an example of excellent engineering in the service of important science.

Vulnerabilities and Limitations

Charles Schue of UrsaNav gave a very detailed and comprehensive paper on wide-area timing, navigation, and data using low-frequency technology. He provided data for timing, location, and data transmission over distances greater than 125 nautical Mmiles.

eLoran. He made the point and showed examples to demonstrate that the technology for these systems exists today, is highly affordable, and can represent a major strengthening of the nation’s critical infrastructure. The systems and hardware he presented are very attractive and seemingly very mature.
Schue was preaching to the choir, as far as I can tell; there is, in the PNT community, no controversy about the need for eLoran. Further, there is a sense of disappointment and wonder that so little money was saved at the expense of great risk to our critical PNT infrastructure, particularly in view of the vulnerability to jamming and spoofing of GPS and the other GNSS systems for civil use; a vulnerability analysis which informed the balance (two) of the papers in this summary report.

Spoofing. Dennis Akos presented data on spoofing tests conducted at Lulea, Sweden, near a low-density commercial airport with limited road traffic and a restricted Swedish Air Force weapons test area, and in Kaohsiung, Taiwan, near a very busy airport with dense roadway traffic. The incidence of radio-frequency interference (RFI) in the latter case was great and in the former case negligible, until the team introduced their jamming and spoofing equipment.In both cases, a simple automatic gain control (AGC) monitoring design, which was computationally efficient, was able to detect and measure the RFI from the jammer-spoofer.

Using all commercial off-the-shelf (COTS) hardware, the jammer was identified and located with time-of-arrival and power-difference-of-arrival. The researchers showed that using a controlled reception pattern antenna (CRPA) like the Stanford four-element CRPA and all-COTS equipment, jammers could be indentified and located efficiently through AGC processing. A large amount of detailed data were presented with screen shots and plots of the effects of the jamming on the receivers.

Proof of Location. Logan Scott of LS Consulting gave a paper on proof of location. He projected the need for location proof in several applications, ranging from system control and data acquisition intrusions that would affect industrial control systems to bogus Mayday calls, the response to which is very expensive, and he provided many examples of data security applications. He also provided several schemes, ranging from cryptographic GPS RF signal structures to the use of overlapping systems, like Galileo and GPS, to enable verification of location.

Scott identified the massive security threat represented by millions of smart phone and tablet users who can store millions of bytes of information, such as maps of sensitive locations. An authorized user of such a map, GNSS-enabled, on a tablet or smart phone, should be able to access the restricted information if the user is in the right location. However, a user, authorized or not, outside of the restricted area would find that area of the map blank if he tries to access it externally, a kind of location need-to-know control.

Scott anticipates the use of temporary keys for weapons usage; such keys would require that the user be in a location authorized for such use. He provides block diagram descriptions of systems that would be feasible to achieve these location proofs for high-value and dangerous operations. These block-diagram level descriptions are accompanied by quantitative assessments of the difficulties and benefits of such system modifications.

It was a compelling tour de force on the subject. We do not have time or space to cover it well but the material has gradually been built up from earlier available publications by Scott at ION conferences and in GNSS journals and magazines. Both the need for such systems and the means by which they may be practically achieved are well worth studying by those responsible for policy and programmatic decisions, and by technologists seeking new product ideas and applications.

And More

A few interesting presentations do not fit into the above categories. Stan Honey, founder of the company Sportvision (the creator of the first-down yellow-line overlay in televised American football, and many other broadcast enhancements for sporting events) and considered sailing’s master navigator, gave a wonderful dinner talk about the PNT technology being utilized in the America’s Cup TV graphics, umpiring, and race management. Honey reflected upon how competitive sailing, unlike other professional sports, has fully adopted the use of advanced PNT technology in how the sport is umpired and managed.

Jason Wither of Microsoft presented a paper on spatialized data for mixed reality, which was very informative in how various types and layers of data are combined to create mixed-reality systems.

Ron Fugelseth of Oxygen productions showed his very entertaining video entitled “A Toy Train in Space.” The video was posted on YouTube a few months ago and immediately went viral. It is a fine example of the use of GPS technology.

James D. Litton heads the Litton Consulting Group and previously played key executive roles at NavCom Technology and Magnavox.

The article “Drone Hack” in the August issue of GPS World and Todd Humphreys’ testimony before a House Subcommittee overseeing the Department of Homeland Security cited results of a spoofing experiment Humphreys conducted with University of Texas colleagues, demonstrating that a drone helicopter, navigating principally on the civil GPS signal, could have its vertical channel spoofed, causing it to descend. Reaction, quite strong from some directions, prompted one observer to investigate whether a “sky-is-falling” perception is fully warranted. Partly for that reason, emails started circulating among various individuals, including some directly involved in the design. When first brought into the group I was not expecting to be the one to summarize, but, as events unfolded, I’m called on to act as techno-sleuth.

Let me first state the conclusion: the sky is not falling. That’s not intended to discourage corrective measures — and it is immediately acknowledged that definitive answers remain unresolved (detailed configuration of the Kalman filter, state estimates, weighting of the baro altimeter). But this much is clear: conditions weren’t 100 percent normal. From here I’ll cover the supporting facts, followed by possible corrective measures. Discussion will be technical, without any hint of administrative authority or approval.

Key revelations came to light in discussion with the chief scientist of Adaptive Flight, who designed the drone’s nav system software and operator interface.

“The reason Todd and his team were able to modify the vertical position of the aircraft even though altitude aiding is actually coming from the pressure sensor,” he stated, “is that the GPS vertical velocity was being used. The spoofed GPS position (altitude error) was actually being ignored.”

We might call that a hybrid mode, using one part of GPS and ignoring another. Selectivity isn’t intrinsically unwise — we need options to reject some data without automatically rejecting other information — but, with GPS-derived altitude ignored for any reason, why not reject all vertical-channel influence from GPS? In fact that’s consistent with normal operation; disabling (again a quote) “GPS vertical velocity as an aid … can be done with a command from the control station (and saved as default for the aircraft).”

Well, then, the demo doesn’t reflect 100 percent normal procedure. Relief: our drones aren’t as vulnerable as we thought, and the fear expressed in various publications can be reduced.

For further support of that conclusion, additional major information from that same designer includes a quote that “The baro altimeter is used to provide a vertical position discrete update to the Kalman filter. This is true for both normal and GPS-denied modes. There are no (automatic) divergence tests in this system. There is some outlier detection/rejection on the GPS (which probably was not triggered in the spoofing tests, but I haven’t seen the data). There is nothing on the baro altimeter.” Finally, he says “it is a trivial change from the control station to make the vertical channel ignore GPS in normal mode by turning off the down GPS velocity measurement update; it would still fly fine.”

The combined weight of all that can justifiably reduce the level of concern — but not all the way down to zero. Now that all this happened, the subject of prevention needs to be addressed.

As Todd Humphreys correctly noted, without spoofing but with existing errors, GPS position updating cannot adequately mitigate low-cost IMU drift.

High-end IMUs bring budget issues (and their motion-sensitive errors limit performance anyway). Spectrum and signal quality is seen by many as an important consideration; residual monitoring is another. For the latter to be effective, the existing (loose) coupling needs upgrading (loose coupling wastes information content; the loss is greatest when GPS coverage is marginal). Extent of refinement (tight/ultratight/deep) and usage of carrier phase (while sidestepping its usual traps) open up a subject with much wider scope: cross-checking. I offer just a few fundamentals here.

• Known data-edit capabilities available with existing provisions (for example, baro altimeter cross-checking), rather than something that “can be done” can always automatically disallow any partial influence from GPS instantly upon spoof detection, regardless of its genesis (Kalman filter bias state traceable to past history or any other source).
• The step just noted generalizes to include all sensor data extant onboard, including carrier phase. The specter of huge expense for this particular step is nonessential; some receivers output raw measurements that can be put into public domain algorithms.
• With access to all the raw data, every solution combination — federated and integrated — can be generated for cross-checking. In all cases, thresholds for residual testing are set with conservative assessments of sensor error statistics; this overbounding enables integrity testing to err on the side of caution (sacrificing some valid data to better ensure rejection of bad). Integrity test algorithms are likewise public domain.

I close by paraphrasing an observation offered by Mitch Narins in a LinkedIn discussion: Deter threats before they happen. With a robust non-GNSS PNT alternative, spoofing will have no affect on safety or security.

 — James L. Farrell
President, VIGIL, Inc.
Severna Park, Maryland

Dear Senator _______________,

Senator __________________,

and Representative _____________,

I write to you as my elected voice in government, regarding a current budget matter of critical importance to both U.S. national security and the U.S. economy. It may not be high on your list — yet — as its importance in both defense and infrastructure is not well understood. But I assure you that it is key to the future of this country, and in many ways to global stability and the global economy as well.

I am talking about GPS. It works well now. It works fantastically well. But it is extremely vulnerable to sabotage, jamming, and spoofing (the intentional falsification of GPS signals). Remedies for and defenses against these weaknesses of the Global Positioning System have been proposed and will work if implemented — but they require some measure of funding support. That’s where you come in.

Under the stewardship of the U.S. Air Force and its GPS Directorate, the constellation of now 31 orbiting satellites is undergoing a progressive modernization, upgrading, and adding new signals for even better service. The third generation of GPS, known as GPS III, is scheduled to begin coming online in 2014. That date has moved significantly to the right since it was first set, and may continue to get postponed, due to budget cuts made by your colleagues in the U.S. Congress.

I believe such cuts, and the corresponding delays, are shortsighted.

GPS III will be more robust than the current GPS II generation, for the benefit of our defense forces worldwide and the many segments of critical national infrastructure (telecommunications, finance, air safety, agriculture, freight, automobiles, and more) that depend on ultra-precise positioning, navigation, and timing provided by GPS to keep this country running.

But even the planned improvements in GPS signals are not enough to forestall intentional harm to the system and to the many critical services it provides.

If you are not already familiar with the downing of aircraft caused by spoofing the GPS signal, see this article. For expert testimony before Congress stemming from this incident and citing recommended measures, see “Taking It to the House.”

For a very realistic possibility of future shock, see “Live Free or Die Hard,” a portrait of the nation under cyber attack.

As I mentioned, there are strong countermeasures proposed to combat these threats to national security and the economy. But they do require money to implement. Not that much money, compared to many other items in the national budget. And very little money — almost none — compared to the damage that a prudent outlay would prevent.

I would be glad to inform you further, provide technical underpinning to these assertions, and put you in contact with government officials who are of the same opinion as I am.

A political act of will is needed to combat future disaster. I hope GPS can count on your support in the budget debates.

Tuesday, the 26^th of June, started off as a beautiful day in Colorado Springs, if you ignored the towering plume of smoke to the west from the Waldo Canyon Wildfire.

The wildfire started three days before in the popular Waldo Canyon hiking area in the Rocky Mountains just off Highway 24. While people in the Colorado Springs area were concerned, there were currently eight other wildfires raging in the state of Colorado and over the past month arsonist(s) were suspected of starting up to 20+ wildfires. So, many had become inured to the sight and smell of smoke. Only one serious wildfire was known to be currently out of control in Colorado at the time, so concerns in the Colorado Springs community could be described as moderate.

Then, at 1630, that’s 4:30 P.M. for my non-military readers, the wildfire displayed its true personality. Driven by what meteorologist later described as “a perfect storm of weather conditions” and howling winds exceeding 65 miles per hour out of the West, the fire spread eastward toward Colorado Springs at an alarming rate.

The dark black roiling smoke blotted out the sun, which was suddenly no more than an angry red disc in the sky providing little illumination. The suddenly disobedient wildfire began marching, indeed running and leaping, relentlessly eastward voraciously consuming homes and lifetimes of memories. My wonderful wife of 32 years and I had all of five minutes to leave our comfortable foothills home, amid swirling, stinging, cloying black smoke, flying embers, and flames that danced over 100 feet high. It was simply a terrifying event. As we fled the wildfire with quickly gathered pictures, important papers, and little more than the clothes on our backs, neither of us thought we would ever see our home of 22 years or anything inside intact again.

Fox 21 file photo of the Waldo Canyon Fire in Colorado Springs, June 26, 2012.

Evacuation

The wildfire and smoke turned a now-indelible drive down familiar streets into an alien landscape. Visibility was limited to less than ten feet and premature night had fallen in a fiery, smoky, unbreathable pall on more than half of Colorado Springs. In the end more than 32,000 people were evacuated, 11,000 homes were threatened in several nearby communities, and approximately 350 homes were lost in the Mountain Shadows neighborhood in the foothills of the Rocky Mountains. Firemen tell me the heat was incredibly intense, and homes that were lost were quickly turned into nothing more than smoky white ash. It was a truly devastating turn of events but without all the capabilities generated by and enabled by GPS, the results could have been much worse. Mayhem was avoided, and I have no doubt that GPS units of various descriptions guided thousands of people to safety that unforgettable day. Thousands of people, who suddenly and unexpectedly found themselves to be evacuees, followed voice and visual commands from small electronic GPS units that eventually led them to safety and safe havens all around the state of Colorado.

Heroes

Firefighters and support agencies from around the U.S. responded. When the fire broke out and wreaked havoc in the Rocky Mountain foothills, there were ~423 firemen fighting the fire. After the breakout and at the height of the fire, there were firefighting assets from every source available including the DoD and the National Guard. They totaled more than 1500 in number, and in my book they are all heroes. Case in point, as we were fleeing down the mountain from our home in a billowing preternatural darkness, along with thousands of others just like us that just wanted to get out safely, the brave men and women of Fire Station #12, at the end of our street, were racing up the mountain to confront the fire and save our homes and our neighborhood. In this regard I hold them and all firefighters in the same regard as U.S. Marines, who when shots are fired run toward the sound of gunfire, not away from it. Our courageous local firefighters, joined by a thousand more from across our nation, were running toward the fire, not away from it. Their bravery brought tears to your eyes that had nothing to do with the smoky atmosphere.

We Survived

All this occurred less than two weeks ago — as I write this column from my home, which was fortunately spared, albeit with a slightly smoky bouquet. We certainly consider ourselves to be blessed as the fire was stopped just a few hundred feet from our neighborhood.

When we finally and gratefully returned home and were able to fire up our computers, I discovered several testimonials from readers, first responders, firemen, and GPS users extolling the virtues first of the firemen and then of the GPS equipment that played such an important role in averting a total catastrophe.

One note from a couple who had only been in the local area for a couple of months described their experience fleeing before the raging wildfire in an only vaguely familiar neighborhood suddenly plunged into darkness, with air that was difficult to breathe and street signs that were unreadable. However, they movingly wrote, “Our brand new Garmin, that led us across country, also led us to safety during the WC wildfire and it was extremely comforting to know that the GPS knew the way…it eventually led us safely to a hotel outside the evacuation area…we had no idea which way to go and were totally dependent on our Garmin…we had a map but in all the confusion and panic it was of very little use…we could not read the map in the sudden darkness…we just listened to that small little voice that said…prepare to turn right in 400 feet…it saved our lives.”

USAFA under Attack by the Waldo Canyon Wildfire.

Another shining example of bravery in firefighting came from the various agencies and firefighters that joined the firefighters from the United States Air Force Academy (USAFA). A USAF Colonel went on local television and declared that they had evacuated the academy and then established what they hoped was an impenetrable several-mile-long firebreak with bulldozers and heavy equipment, and although their numbers were limited, they would not allow the fire to penetrate the USAFA beyond that line and hold the line they did. These brave men and women were not all trained and certified wildfire firefighters, but they had the courage of their convictions and they held the line. The fire did not penetrate the USAFA beyond that firebreak. There are many more examples of true heroism that are too numerous to mention.

Firefighters from across the Nation

I spoke with many first responders — as I said, eventually 1500+ were fighting the fire — from as far away as California and Utah, who knew nothing about Colorado Springs or the Rocky Mountains to the west when they arrived on the scene, but who efficiently navigated the fiery wasteland with their map reading skills and various official and commercial/civil GPS units, both stand-alone and embedded units. And again Garmin units were almost always mentioned in the conversation — from sophisticated Garmins using elaborate forestry and military grid systems used by military and Forest Service first responders, in vehicles and aircraft, to wrist Garmins that simply allowed users to immediately locate their positions on a local area map.

At the height of the WC Wildfire, which as I write this is 98% contained but most certainly not under control, there were firefighters and first responders from the Forest Service, U.S. Army, U.S. Air Force, National Guard (Army and Air Force), the U.S. Air Force Academy, and numerous federal agencies to include C-130 MAFF (Modular Airborne Fire Fighting System) units from Peterson AFB, in Colorado Springs (the 302^nd) and from a National Guard Unit in Wyoming. The majority of the firefighters were not from the local area; consequently, most all of them were using an incredible array of various GPS devices to locate and navigate. And in most all cases there was some reference to an external map. Local television stations, which covered the fire exclusively for the first five days, all had different and multiple maps and many were frankly almost indecipherable. What was interesting is that in almost every case there was a definite and clearly visible unfamiliarity by the participants with both the maps and even the local area. It seems that except for certain branches of the military and those who use maps daily in their profession, map reading and orienting skills have fallen by the way side, if indeed there was ever any initial proficiency. It is a skill we all need to relearn.

Maps and GPS

A very close friend and business colleague of mine, Robert Rosenberg (Maj Gen USAF Retired), once ran what was then known as DMA or the Defense Mapping Agency and is now known as NGA or the National GeoSpatial Intelligence Agency. NGA specializes in maps and may be the best in the world at gathering the necessary data and producing them. Indeed, some of the NGA maps are simply amazing and true works of art. However, the sad fact is they are utterly useless if you don’t know how read and utilize them properly.

Historically, some of the inaccuracies wrongly attributed to the GPS were actually map errors. I personally observed an incident where Dr. Ivan Getting, a possible father of the GPS, whom I have written about previously, determined the exact geographical coordinates of his home from a long integrated GPS position, but which DMA maps showed to be in the middle of a lake. Obviously the map was several hundred meters in error, and this was a common occurrence in the “old” days. However, modern map-making techniques and accuracies today are such that this is no longer the case. But even the best and most accurate map in the world today is useless if we don’t know how to make use of it — we must learn to orient ourselves, accurately locate our position on a map, and generally make use of the features all modern maps provide. It is time to stop blaming the maps and map makers and start learning to use the phenomenal maps and PNT tools at our disposal.

Now, please don’t misinterpret my comments or take them out of context. After all, this is GPS World magazine and there is not a greater proponent of GPS anywhere than yours truly; however, I have also always been a proponent of developing simple map reading skills as well, which to some seems to be anything but simple.

Dwindling Skillsets

Like many of you, I have read passionate and somewhat inaccurate articles bemoaning the use of GPS for the navigation and situational skills that are lost by blindly following GPS dictates, and certainly I have received numerous letters from and responded to those who prefer to navigate using granddad’s old Texaco map in the glove compartment. However, unlike many uninformed critics of the GPS and proponents of map reading skills, I do not believe the two are mutually exclusive. In fact, one of the features I most appreciate about the GPS navigation system in my Audi is the traffic avoidance feature that when potential routes are blocked, or conflicts arise, automatically reroutes, without ever broadcasting that most irritating word “recalculating.” The other feature is the map display zooms out and displays more map features and alternate routes, so if I wish I may manually choose an alternate route. I have, just as you do, the option of blindly trusting the GPS, picking my own route on the map display or, as I most frequently do, using a combination of both map-reading skills and PNT automation.

In the grand scheme of things, map-reading skills are not difficult to develop and the basics are simple; however, it does take some practice — practice that can be gained every day by choosing different routes to work or common destinations and challenging yourself and your map reading skills when you travel. And here is a novel idea — actually read the instructional/operators manual that came with your GPS — learn all its secrets and built-in capabilities. You might be surprised by what you will learn and the skills GPS can help you develop.

Plethora of PNT Equipment

I had the enviable opportunity to speak with representatives from many of the more than 20 agencies that responded to the Waldo Canyon Wildfire and get a brief look at some of their PNT equipment. The equipment in general ranges from high end and highly sophisticated official first responder units with built-in communications capabilities to Garmins, iPhones, and iPads. The Garmins were equally split between vehicle-mounted, aircraft-mounted, and portable units, while the more sophisticated units were large and considered more appropriately as portable units with communication capabilities than as true handhelds. By far the most noticeable and prevalent units, other than Garmins, were Apple iPads, especially the new iPad IIIs with retina displays and ruggedized with Otterbox and Otterbox-like enclosures. There are numerous mapping and GPS/GIS applications that run on the iPad and other portable display devices, and in the future I will be reviewing the best mapping applications to assist you in choosing the one that is best for your situation. However, regardless of the application or device it would behoove us all to learn a bit more about maps and the devices we have on hand to display them, to include becoming familiar with that old Texaco map in the glove compartment, even if it is a last resort.

Tragically two souls perished in the Waldo Canyon Wildfire, as they were unable to evacuate their home before the fast moving wildfire overcame them. The Waldo Canyon Wildfire is truly a catastrophic event that will long be remembered in Colorado, and from which we can all learn a valuable lesson. And I wholeheartedly believe that many lives were and will continue to be saved by GPS/PNT devices in these types of catastrophes. We simply owe it to ourselves and our loved ones to learn how to best use our GPS/PNT equipment now, so it will be second nature when a catastrophe occurs. Take it from me, you life may depend on it. When you are fleeing for your life, you need all the help and good fortune available — it is not the time to figure our how your GPS/PNT device really functions.

God bless our firefighters and first responders.

Until next time, as Tennessee Ernie Ford said, “God willin’ and the creek don’t rise,” happy navigating and remember to read your GPS/PNT equipment owners manual.

Eric Gakstatter

In my 20-plus years of involvement in the GPS/GNSS industry, nothing has come close to the LightSquared debate for technical and political complexity, nor for potential effects on nearly every high-precision GPS/GNSS user in the United States. The industry’s destiny is somewhat controlled by a federal agency that is not very knowledgeable about how, when, and where GPS is used — although I’m sure they’ve learned a lot in the last 14 months.

While receiver manufacturers have a firm grip on the technical complications of what LightSquared proposed, they have jockeyed for market position, as information released to the public is filtered through their marketing heads. Finally, media coverage is all over the place, from “LightSquared is doomed” to “this will happen.”

On January 13, as we all know, the U.S. deputy secretaries for defense and transportation wrote, on letterhead of the Space-Based Positioning Navigation & Timing National Executive Committee (PNT EXCOM), to the head of the National Telecommunications Information Administration (NTIA), declaring that “there appear to be no practical solutions or mitigations that would permit the LightSquared broadband service, as proposed, to operate in the next few months or years without significantly interfering with GPS.”

On February 14, the NTIA director wrote to the Federal Communications Commission (FCC) chairman in a similar vein with nearly the same language. That same day, the FCC stated its intent to “not lift the prohibition on LightSquared,” and to “vacate the Conditional Waiver Order, and suspend indefinitely LighSquared’s Ancillary Terrestrial Component authority.”

It just so happens that LightSquared cannot accomodate military GPS users nor aviation GPS users. Those of you who use high-precision GPS can thank your lucky stars that the military and aviation folks are standing in your corner. Otherwise, as I warned back in May of last year, high-precision users would have been thrown under the onrushing bus of national broadband.

In testimony to a House of Respresentatives subcommittee meeting on GPS and aviation in early February, the Transportation deputy secretary revealed that the Federal Aviation Administration (FAA) spent more than $2 million of taxpayer dollars with two different independent labs to conclude that LightSquared proposals were not compatible with several GPS-dependent air safety-of-flight systems.

Don’t expect the Department of Defense (DoD) ever to provide similar testimony. The Pentagon played its veto card off-air and out of the public eye.

LightSquared has continued to complain about GPS receivers “looking into our spectrum” as the reason for the interference GPS receivers are suffering. If you missed Richard Keegan’s December 2011 article in GPS World, you should take a look. He succinctly addresses this issue, as I did in my November 2011 Survey Scene column.

As LightSquared has clearly lost the engineering argument, it has taken a very creative approach in an attempt to convince the FCC that this isn’t an engineering problem, but rather all about the FCC rules. LightSquared petitioned the FCC to confirm that “GPS devices are not entitled to protection from interference.”

Crazy statement? If you think so, see if you recall reading this statement on equipment such as GPS receivers. It is on almost every electronic device that relies on radio signals.

“This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:

“(1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.”

What if LightSquared can convince the FCC that GPS receivers do, indeed, fall within the confines of Part 15 of the FCC rules and aren’t entitled to interference protection? That’s what the company is trying to do, and that’s why this fight ain’t quite done.

Don’t underestimate the power of the White House pushing the National Broadband Plan, or of commercial interests — of which there are myriad — seeking to turn a buck on the hunger, whether real or only perceived, for limitless broadband. Even the transportation depsec allowed in his testimony as how “in the Obama administration, we believe deeply in what LightSquared is attempting to do, which is to make the Internet more accessible to more people all across the country. This is an urgent national priority.”

Communications for My RTK

Some people in the GPS industry who believe that the LightSquared service will do wonders for RTK operations, somehow replacing the communications methods we currently use (UHF/VHF, 900MHz, GSM/GPRS, CDMA, Wifi/Mifi, etc.). I disagree.

LightSquared was relying on Sprint’s infrastructure (~31,000 towers) for its terrestrial operations, supplementing them with ~3,400 LightSquared towers at some point. I’ve used Sprint’s mobile phone service for about 12 years and I used Sprint’s data card service for several years (not any longer). I pretty much know that Sprint is good for metro areas and poor for rural areas. Like other wireless providers (AT&T, Verizon, T-Mobile, etc.), Sprint is strong in some geographic areas, and weak in others. Since LightSquared is focused on serving people (densely populated areas) rather than geographic areas (e.g., farmlands), their terrestrial service is not going to be even close to being nationwide. LightSquared’s solution for areas not covered by their terrestrial service is to use satellite communications for Internet connectivity.

If you think you would enjoy ubiquitous coverage with satellite communications for your RTK operations, consider OmniSTAR’s service, which is in the same spectrum as what LightSquared proposed. OmniSTAR works great when there’s a clear view of the sky to one of OmniSTAR’s satellites (ironically, operated by LightSquared) such as in the agriculture industry. But I’ve used it a bit and — just like GPS — it doesn’t work in buildings, in vehicles, under trees, or in other obstructed-sky locations.

Can you imagine using a LightSquared mobile phone that doesn’t work in buildings, in cars, or under trees? You wouldn’t. Anyone who’s ever used RTK knows that spotty base/rover communications is the quickest way to spoil an RTK party. With GPS/GLONASS receivers allowing us to use RTK in places where we’ve rarely ventured before, the limitation wouldn’t be the number of navigation satellites in view, but rather if the LightSquared satellite was in view.

For those of you who heard that LightSquared might have been a good idea in order to make wireless mobile Internet access more affordable, I seriously doubt that statement as well. Documents in a huge Freedom of Information Act release by the FCC reveal what LightSquared was planning to charge its wholesale customers (not retail) when they were out of range of the terrestrial system and forced to use LightSquared’s satellite for wireless broadband. The wholesale cost of their satellite broadband service was to be $10 per megabyte (not gigabyte), an astonishingly high price for a company that’s been touting affordable, nationwide wireless broadband Internet service.

Upgrade Costs

A cool $2.4 billion was the official estimate given for aviation industry upgrades, should LightSquared have gone forward. I think that’s conservative because I doubt it covers the infrastructure upgrade cost (WAAS, GBAS, and so on) or the cost of NextGen program delays.

How about something closer to home? I queried the administrator of a statewide RTK network of 103 GNSS reference stations, and used his estimates to extrapolate national costs in that regard: 7,000 CORS receivers across the United States. They look like this: optimistic scenario, $64 million; likely,$92 million; worst-case scenario, $120 million.

Keep in mind that this is only the high-precision GPS/GNSS infrastructure in the United States. There are still hundreds of thousands of high-precision GPS/GNSS receivers owned by users across the country that would have to be upgraded. For many GPS receivers (think handheld), there will be no upgrade solution, so the manufacturer might offer trade-in credit for a new GPS receiver.

After spending time to understand the actual costs of accomodating LightSquared, one state legislator who initially voiced his support for LightSquared said “we can’t afford it.”

New Beginnings

Included in the NTIA report was a recommendation that, with time, GPS receivers could be redesigned in order to accomodate LightSquared’s 10L signal.

NTIA also reported that during the January 13 EXCOM meeting, it was agreed that “federal agencies will move forward this year to develop and establish new GPS spectrum interference standards that will help inform future proposals for non-space commercial uses in the bands adjacent to the GPS signals and ensure that any such proposals are implemented without affecting existing and evolving uses of space-based PNT services vital to economic, public safety, scientific, and national security needs.”

In summary, GPS/GNSS receiver designs will change in the coming years and move towards more efficient use of spectrum. To me, a critical statement in the NTIA letter to the FCC is “without affecting existing and evolving” — meaning that not only should GPS be considered, but also GPS-like systems from other countries such as Russia’s GLONASS, Europe’s Galileo, and other developing satellite navigation systems and applications.

ERIC GAKSTATTER is contributing editor for survey of GPS World, and editor of Geospatial Solutions.

Perhaps you don’t track suspected criminals in your spare time, nor do you design or supply a GNSS product that does so. Still, the fresh Supreme Court ruling on GPS use for this purpose reverberates for you, in ways yet unknown. The most interesting part of the court’s ruling pops up in a somewhat open-ended “what if” comment concerning future issues that at least one justice thinks the court should address.

GPS trackers are a form of search, and police must obtain a search warrant to use them, the court unanimously ruled. This comes as a setback to government and police agencies who increasingly rely on GPS surveillance. Justice Scalia said the government’s installation of a GPS device to monitor a vehicle’s movements constitutes a search and violates the Fourth Amendment’s protection against unreasonable search and seizure.

Justice Samuel Alito further said the court should address how expectations of privacy affect whether warrants are required for remote surveillance using electronic methods that do not require the police to install equipment, such as GPS tracking of mobile telephones. “If long-term monitoring can be accomplished without committing a technical trespass — suppose for example, that the federal government required or persuaded auto manufacturers to include a GPS tracking device in every car — the court’s theory would provide no protection,” Alito wrote.

This, or its exact counterpart, has already occurred in cell phones: government-mandated location technology embedded in all devices, over a sliding timescale that comes to maturity, or full application, fairly soon.

The words “no protection” in Justice Alito’s opinion appear to state that personal cell-phone records are open season to government investigators. Such has already been the case in a number of instances.

Murkier than government use — if such a concept is conceivable — is commercial use of a consumer’s location data. In other words, privacy. This issue has been raised since GPS-enabled phones were first theorized, and since the very whisper of the first location-based service, but it has never been fully or adequately addressed by anyone in industry or government.The notion of “granting permission” to use one’s location data, in order to benefit from services thus provided, still seems unresolved to me.

Presumably, we are all waiting around for a test case, such as that of the Jeep owner in the Supreme Court just now. With LBS poised — same as it ever was — on the brink of widespread acceptance, it might benefit everyone if such a case came sooner rather than later.