The System: One Step Back, Three Steps Forward

Galileo IOV Bird Mute; New Draft ICD; CS Proved; Late August Launch

Orbiting in silence since an onboard power mishap on May 27, troubled E20 emitted cheeps from space on August 6, 7,  and 8, broadcasting on the L1 frequency. Nothing has been heard since. 

Meanwhile, the European Commission (EC) published a new draft version of the Galileo Open Service Signal in Space Interface Control Document (OS SIS ICD), issue 1, revision 2, on June 30. It is available for download and comment, the latter period extending to September 22. The EC’s open public consultation process seeks  to ensure that any further development of the Galileo OS SIS ICD takes into account the views of key GNSS stakeholders. An online form for submitting comments is available.

Galileo E20, also known as GSAT0104, the fourth in-orbit validation (IOV) satellite, has been set “unavailable until further notice” according to the European GNSS Service Centre because of a sudden, unexpected loss of power on May 27.

Based on a selected set of IGS MGEX stations and all CONGO stations, the first signals were tracked at AREG, AUT0, LLAG, and UNB3 at 23:13:00. No E5 signals and no navigation messages are currently transmitted. Some JAVAD GNSS receivers report from time to time false E5a locks with zero or extremely small C/N₀.

Galileo’s Early Proof of Concept (EPOC) team has successfully tracked the encrypted Galileo E6-B and E6-C signals broadcast by Galileo satellites. As a result, the Commercial Service loop has been closed using both encrypted and non-encrypted signals.

The completed dispenser unit is ready to be transferred from the S5 payload preparation facility for its integration atop Soyuz’ Fregat upper stage.

During a 10-day testing period, receivers in Tres Cantos, Spain and Poing, Germany, showed the successful tracking and data demodulation of the encrypted signals from the available Galileo satellites, with periods where all satellites transmitting E6 encrypted signals were tracked simultaneously. The tests verified the Galileo Commercial Service (CS) signal’s encryption functionalities, with the data received containing authentication and high accuracy information previously generated outside the Galileo system. This is an essential feature to ensuring Galileo’s high accuracy and authentication services.

The Galileo Commercial Service will deliver a range of added-value features, including positioning accurate to decimeter level and an authentication element. The Galileo CS demonstrator began its proof of concept earlier this year, with early service expected to start in 2016.

Once operational, the CS will provide access to two additional encrypted signals on the E6 band, delivering a higher data throughput rate and increased accuracy. The tests are the result of a collective effort involving teams and projects of AALECS (Authentication and Accurate Location Experimentation with the Commercial Service), supported by the European Commission, the GSA, the European Space Agency (ESA), and the Galileo operator Spaceopal.

The AALECS project is building a platform to connect to the European GNSS Service Centre (GSC) and transmit real-time CS data through the Galileo satellites. This platform will be operational by 2015 and will demonstrate the real performance of future high-accuracy and authentication services of Galileo prior to early service availability.

The European Commission launched AALECS in January 2014, and it was awarded to a consortium led by GMV including CGI, Qascom, IFEN, Veripos, and KU Leuven. 

New Launch. At press time, the next Galileo satellites were set to launch on August 21, ushering in the system deployment phase and paving the way for the start of initial services. Galileo SATs 5 and 6 were scheduled to lift off from Europe’s Spaceport in French Guiana on top of a Soyuz rocket. They are expected to become operational, after initial in-orbit testing, in autumn.

The two satellites will join the four Galileo in-orbit validation satellites already in space. Launched in pairs in October 2011 and October 2012, these four — the minimum required to obtain a position fix — demonstrated and validated the system’s space and ground segments.

SATs 7 and 8 are scheduled to follow by end of year 2014.  Then the constellation will be gradually deployed with six to eight satellites launched per year, along with addition of remaining elements of the ground network.

Adjacent-Band Compatibility Workshop Set for D.C.

The U.S. Department of Transportation is holding a “GPS Adjacent Band Compatibility Assessment Workshop” on September 18, 10 a.m.–5 p.m. Eastern Daylight Time. Registration for the workshop is required, and closes September 4. The general public can either attend in person or via WebEx.

The workshop is being held to discuss implementation of a GPS Adjacent Band Compatibility Assessment. Discussion will focus on the various implementation steps of the assessment, including development of GPS receiver use cases, identification of representative GPS receivers, and development of a test and analysis program. “In particular, emphasis will be placed on the information needed from GPS receiver and antenna manufacturers, and the logistics of procuring and handling that information to safeguard manufacturer proprietary data,” according to the Federal Register.

The sponsoring agency is the Office of the Assistant Secretary for Research and Technology, Department of Transportation.

To register, send the following information to stephen.mackey@dot.gov:

• Name
• Organization
• Telephone number
• Mailing and email addresses
• Attendance method (WebEx or on site)
• Country of citizenship

The meeting will be held at the U.S. Department of Transportation, John A. Volpe National Transportation Systems Center, 55 Broadway, Cambridge, MA 02142. ID is required to enter the building. For details, see the Federal Register notice.

GPS IIF-7 Successfully Launched

Last USAF Launch to Rely on Radar as GPS Tracking Takes Over

A United Launch Alliance (ULA) Atlas V rocket carrying the seventh GPS IIF satellite for the U.S. Air Force launched at 11:23 p.m. EDT Friday, August 1 (03:23 UTC, August 2), from Space Launch Complex-41 at Cape Canaveral, Florida.The Boeing-built satellite has sent the signals to controllers that confirm it is currently operating properly within the constellation.

Boeing and the Air Force will complete the full on-orbit checkout of the satellite in August. The GPS IIFs offer improved signal accuracy, better anti-jamming capability, longer design life and the new civilian L5 signal.

“We are providing our Air Force partner and GPS users with a steady supply of advanced GPS IIFs,” said Craig Cooning, president of Boeing Network & Space Systems. “Our robust launch tempo requires vigilance and attention to detail, and mission success is our top priority. We continue to partner with the Air Force and ULA to effectively execute the launch schedule.”

GPS IIF-7 is the seventh of 12 such satellites Boeing has built for the U.S. Air Force, and the third on-orbit delivery this year. GPS IIF-8, slated for launch during the fourth quarter, arrived at Cape Canaveral on July 16 to undergo final launch preparations. GPS IIF-7 will join a worldwide timing and navigation system utilizing 24 satellites in six different planes, with a minimum of four satellites per plane positioned in orbit approximately 11,000 miles above the Earth’s surface.

“Congratulations to the U.S. Air Force and all of our mission partners on the successful launch of the Atlas V carrying the GPS IIF-7 satellite,” said Jim Sponnick, ULA vice president, Atlas and Delta Programs. “ULA launch vehicles have delivered all of the current generation of GPS satellites, which are providing ever-improving capabilities for users around the world.”

This mission was launched aboard an Atlas V Evolved Expendable Launch Vehicle (EELV) 401 configuration vehicle, which includes a 4-meter-diameter payload fairing. The Atlas booster for this mission was powered by the RD AMROSS RD-180 engine, and the Centaur upper stage was powered by a single Aerojet Rocketdyne RL10A engine.

The EELV program was established by the United States Air Force to provide assured access to space for Department of Defense and other government payloads. The commercially developed EELV program supports the full range of government mission requirements, while delivering on schedule and providing significant cost savings over the heritage launch systems.

C-Band Radar. The launch August 1 marked the final time the Air Force is expected to rely on C-band radars to track rockets immediately following liftoff.

Future Air Force launches, both from the Cape and from Vandenberg Air Force Base in California, will rely on GPS signals for post-liftoff tracking, service officials said. The Air Force and its primary launch services provider, ULA, have been working for years on the capability, which features rocket-mounted GPS receivers that transmit position-location data to controllers on the ground.  

“It’s something that’s been a long time coming,” Walt Lauderdale, GPS IIF-7 mission director, said during a July 25 conference call with reporters. The new technique has been tested and proven at both at Cape Canaveral and Vandenberg over the last few years, he said.