The next GPS satellite launch is scheduled for May 15 with the launch window extending from 21:39 to 21:58 UTC. An Atlas 5 rocket will be used to place the satellite, GPS IIF-4, into orbit from Cape Canaveral Air Force Station.

This is the first time in almost 28 years that an Atlas rocket will be used to launch a GPS satellite. All of the prototype or Block I satellites were orbited with Atlas rockets. Since then, Delta rockets have been used exclusively for GPS launches. The IIF satellites are being launched with a mixture of Atlas and Delta rockets.

The IIF-4 satellite, also known as SVN66, will operate as PRN27. SVN66/PRN27 will eventually occupy the C-2 slot, replacing SVN33/PRN03, a Block IIA satellite launched in 1996. Reportedly, SVN66/PRN27 will go through an extended period of testing following launch, and is not expected to be set healthy until August. SVN33 will become a reserve or backup satellite.

Ground Stations: ER = Eastern Range; BOSS = Call sign of New Hampshire Station, New Boston Air Force Station, New Hampshire; LION = call sign of Telemetry & Command Station, Royal Air Force Oakhanger, Hampshire, U.K.; Diego Garcia = Diego Garcia Station (call sign REEF), British Indian Ocean Territory; Guam = Guam Tracking Station (call sign GUAM), Dededo, Guam.
TDRS: Tracking and Data Relay Satellite
MES1: Centaur first main engine start
MECO1: Centaur first main engine cutoff
MES2: Centaur second main engine start
MECO2: Centaur second main engine cutoff
At spacecraft separation, the GPS satellite’s orbit will be circular with a height of 11,047 nautical miles or 20,459 kilometers and an inclination of 55 degrees.

(Courtesy of SpaceFlight Now) This is the 45th Launch Support Squadron crew patch for the GPS 2F-4 mission, which is Boeing’s Space Vehicle (SV) #5. Each SV is a named for a navigation star and its constellation. SV-5 is named Vega, with constellation Lyra. On the patch, they are the large star and constellation in the background of space. The United Launch Alliance Atlas 5 rocket is shown lifting the satellite from the Eastern Launch Site at Cape Canaveral Air Force Station. The Squadron mascot is a gator, and a lyra is a Greek harp. SSgt Thomas Hogan drew a “Toga-Gator” and Lt Ken Stuart did the patch design.

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.

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.

The agencies want to know how users use NDGPS, and are seeking ideas for future uses or alternative uses.

According to the notice in the Federal Register,”The NDGPS was designed to broadcast signals to improve the accuracy and integrity of the Global Positioning System (GPS) derived positions for surface transportation, as well as other civil, commercial, scientific, and homeland security applications. This analysis will be used to support future NDGPS investment decisions by the Department of Homeland Security and the Department of Transportation beyond fiscal year 2016. This notice seeks comments from federal, state, and local agencies, as well as other interested members of the public regarding current and future usage of the NDGPS, the need to retain the NDGPS, the impact if NDGPS signals were not available, alternatives to the NDGPS, and alternative uses for the existing NDGPS infrastructure.”

NDGPS is a ground-based augmentation system that provides increased accuracy and integrity of GPS information to users on U.S. land and waterways. The system consists of the Maritime Differential GPS System operated by the U.S. Coast Guard and an inland component funded by the Department of Transportation. NDGPS is built to international standards, and similar systems have been implemented by 50 countries around the world. Modernization efforts include the High Accuracy NDGPS (HA-NDGPS) system, currently under development, to enhance the performance and provide 10-15 centimeter accuracy with integrity throughout the coverage area. For more information about NDGPS, visit the following webpages:

Comments and related material must reach the Docket Management Facility on or before July 15, 2013.

Comments can be submitted identified by docket number USCG-2013-0054 or RITA-2013-0001 using any one of the following methods:

1. Federal eRulemaking Portal: http://www.regulations.gov.
2. Fax: 202-493-2251.
3. Mail: Docket Management Facility (M-30), U.S. Department of Transportation, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, D.C.   20590-0001
4. Hand delivery: Same as mail address above, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The telephone number is 202-366-9329.

All comments received will be posted, without change, to http://www.regulations.gov and will include any personal information provided.

For more details on submitting comments, see the Federal Register notice.

More information on the status of the NDGPS can be found on the RITA site and the U.S. Coast Guard site. More information on the HA-NDGPS is at the U.S. Department of Transportation site.

Navsys assisted in the development of the Colorado Department of Transportation’s Emergency Vehicle Location System Mayday platform in 1995. To address the need for faster notification and responsiveness during emergencies, Navsys was contracted to integrate GPS positioning into a cell phone so that location information could be sent to a communications center for mobile 911 calls.

One of the enabling technologies Navsys developed for this system was LocaterNET. When activated by a user’s in-vehicle unit (IVU), LocaterNET collects a snapshot of raw GPS information. That information is then sent to a remote processing system to determine the user’s location. This technique allowed for low power consumption and processing requirements for the IVU, which is vital for small form factor personal navigation and communication devices.

“We are honored to be a part of this exhibition and for the awareness it creates for how GPS technology has advanced many other technologies we use today,” said Alison Brown, president and CEO of Navsys.

The Smithsonian exhibition covers a multitude of navigation and timing innovations and opens on April 12. A detailed description of the LocaterNET Mayday platform can be found here.

GIOVE-A has been able to fix its position, velocity and time from GPS signals, despite orbiting more than 1000 km above the downward-pointing U.S. satellites.

“Satellite navigation has become almost as indispensable for most low-orbiting satellites as it is for car drivers and other terrestrial users,” said ESA’s Steeve Kowaltschek. “Satellites equipped with satnav receivers can continuously monitor their orbit in space, enabling largely autonomous operations with limited ground intervention. GIOVE-A’s three months of data show that future geostationary satellites could operate in the same way, bringing real competitive advantage to the multi-billion-euro telecommunications satellite market.”

GIOVE-A has been able to make use of signals emitted sideways from GPS antennas, within what is known as side lobes.

GPS Side Lobes. GPS satellites — like those of Galileo, Russia’s Glonass or their Japanese, Chinese and Indian counterparts — aim their antennas directly at Earth. Any satellite orbiting above the GPS constellation can only hope to detect signals from over Earth’s far side, but the majority are blocked by the planet. For a position fix, a satnav receiver requires a minimum of four satellites to be visible, but this is most of the time not possible if based solely on front-facing signals.

Instead, GIOVE-A makes use of signals emitted sideways from GPS antennas, within what is known as side lobes. Just like a flashlight, radio antennas shine energy to the side as well as directly forward.

“These side lobes are not typically well measured because this is energy that doesn’t reach users on Earth,” explained Kowaltschek. “Antenna designers seek to minimize them, but the laws of physics mean they will always be present in some form. Measuring these GPS side lobes has shown them to be stronger than anticipated, and the combination of side lobes and signals spilling over from the other side of Earth mean that a position fix can be maintained throughout GIOVE-A’s orbit.”

The satellite has also acquired detailed profiles of the signal side-lobe characteristics of the various GPS design blocks.

Geostationary satellites reside in set orbital slots, some 80-km across, up in the 36,000-km-altitude belt. Chemical thruster firings are needed every fortnight or so to correct for drift, checked against radio ranging from the ground.

Harnessing satnav would be a way of automating station-keeping functions. It also meshes with the current move to all-electric comsat designs, such as ESA’s Electra. Electric propulsion would do the job of conventional chemical thrusters, delivering more compact satellites capable of flying on cheaper launch vehicles while offering longer mission lifetimes. But electric propulsion provides lower thrust and therefore requires almost permanent ground ranging. Continuous position fixes via satnav could perform this task onboard, maintaining the orbit position with better accuracy.

SmallGeo.

In addition, constant orbit determination and close-to-perfect time knowledge also improves pointing accuracy on comsats that use startrackers as their main attitude sensor.

All-electric comsats using satnav could gradually steer themselves up to geostationary orbit following launch, further slashing the required launcher size, onboard fuel and ground support.

“We envisage a future satnav receiver that can track not only GPS, but also Galileo and Glonass signals at high altitudes, meaning a near-continuous availability of accurate position and time for geostationary and other satellites,” says Martin.

As a next step, a receiver will be flown on ESA’s SmallGEO telecom mission, due for launch in 2014. Building on the positive results of the GIOVE-A experiments, SmallGEO will be the first civilian mission to use satnav in geostationary orbit.

The GPS III program will replace aging GPS satellites, while improving capability to meet the evolving demands of military, commercial and civilian users. GPS III satellites will deliver three times better accuracy and up to eight times improved anti-jamming signal power while enhancing the spacecraft’s design life and adding a new civil signal designed to be interoperable with international GNSS.

The Air Force plans to purchase up to 32 GPS III satellites. Lockheed Martin is under contract for production of the first four GPS III satellites, and has received advanced procurement funding for long-lead components for the fifth, sixth, seventh and eighth satellites.  The successful dPDR addresses design modifications, agreed on by the Air Force and the Lockheed Martin-lead industry team, which will provide new capabilities for GPS III Space Vehicle 9 (SV09) and beyond, including the addition of a search and rescue satellite payload and a Laser Retroreflector Array (LRA). 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.

“We have worked very closely with the Air Force and GPS community to make GPS III the most affordable and lowest risk solution for bringing new capabilities to the GPS constellation,” said John Frye, Lockheed Martin’s GPS III capability and affordability insertion manager. “The design modifications from this dPDR address ways to further reduce Air Force launch costs by $50 million per satellite through dual launch of two GPS III space vehicles on a single booster. This successful dPDR milestone sets the stage to proceed with SV09 design maturation.”

From the beginning of the program, the Lockheed Martin team has remained focused on affordability for GPS III, the company said, while working to ensure the enhanced satellite system can evolve to continue to meet the world’s global navigation and timing needs for the next 30 years. To help reduce risks and cut costs, the GPS III team developed a GPS Non-Flight Satellite Testbed (GNST), which serves as the program’s ground pathfinder and vehicle demonstrator for the first complete satellite. The entire GPS III development and production sequence uses the GNST to provide space vehicle design level validation; early verification of ground support and test equipment; and early confirmation and rehearsal of transportation operations.

Lockheed Martin team has met recent milestones and appears to be on track to deliver the first GPS III satellite, for launch availability in 2014.

In February, the Lockheed Martin team successfully turned on power to the system module of the program’s first spacecraft, designated GPS III Space Vehicle 1 (SV01), demonstrating mechanical integration, validating the satellite’s interfaces, and leading the way for electrical and integrated hardware-software testing.  The satellite will complete its Assembly, Integration and Test (AI&T) in Lockheed Martin’s new GPS Processing Facility (GPF) designed for efficient and affordable satellite production.

The GPS III team is led by the Global Positioning Systems Directorate at the U.S. Air Force Space and Missile Systems Center. Lockheed Martin is the GPS III prime contractor with teammates ITT Exelis, General Dynamics, Infinity Systems Engineering, Honeywell, ATK and other subcontractors. Air Force Space Command’s 2nd Space Operations Squadron (2SOPS), based at Schriever Air Force Base, Colorado, manages and operates the GPS constellation for both civil and military users.

Adapted from a Mercedes Benz Sprinter van, this unique measurement vehicle has been delivered to ESTEC by Austria’s Joanneum Research institute. “This is a dual-purpose vehicle, suitable for both telecommunications and navigation system testing,” explained Simon Johns of ESA’s Radionavigation Systems and Techniques Section.

“For navigation, we have the Galileo constellation coming on stream, as well as the stepping up of ESA’s GNSS Evolution programme — designing what comes next after Galileo’s first generation.”

The four wheel-drive vehicle can host a three-person team, and is crammed with dedicated navigation and telecommunication monitoring equipment.

Testbed vehicle screen.

“One of the main goals driving the design was to have an ‘easy to adapt’ test platform suitable to set up test campaigns for different mobile satellite systems and standards that would require different types of antennas and specific receiver/transmit equipment,” explained Olivier Smeyers of ESA’s Communication-TT&C Systems and Techniques Section.

“On the telecommunications side, there is a continuous effort to enhance current and create new mobile satellite-based broadcast and interactive services via the evolution of current systems or developing new standards,” Smeyers said. “Testing in the field is an essential element for validating and eventually establishing evolved or new standards. The vehicle has built-in multimedia equipment, including storage and control computers, multimedia gateway, passenger LCD screens, cameras and microphones, to serve this purpose.”

The vehicle’s 8-meter-high telescopic mast.

The vehicle features include two removable roof plates to mount specialized antennas (one currently hosts the antenna of a Broadband Global Area Network satellite terminal for Internet connectivity and multimedia and data streaming), an 8-meter-high telescopic mast capable of carrying 25 kilograms, a rubidium atomic clock synchronized to GPS time with nanosecond accuracy, a high-end spectrum analyzer and oscilloscope for signal measurements, and mobile temperature sensors to monitor the rack equipment.

A fish-eye video camera incorporating onscreen GPS timing and positioning performs continuous recording of its surroundings — to throw light on high buildings, trees, or other factors that might affect results.

Internal and external generators yield up to 5 kilowatts to keep everything running — sufficient power to supply two typical European households.

“The challenge was to fit in all the equipment and provide the necessary power and air conditioning, while still weighing less than 3.5 tonnes,” said Thomas Prechtl of Joanneum Research. “Exceeding this weight would have meant drivers would have needed a special license, and potentially limited its operations in some European nations.”