Global Navigation Satellite Systems Engineering, Policy, and Design
Iridium Satellite LLC graphicThe Boeing Company has received a three-year, $153.5-million cost-plus-fixed-fee contract to continue its efforts to augment GPS for military applications by exploiting the Iridium low earth orbit (LEO) communications satellite system.
By Glen Gibbons
GIOVE-A/B Double Difference Ambiguity Measurements, TU DelftResearchers at Delft University of Technology (TU Delft), the Netherlands, succeeded this week in simultaneously tracking the GIOVE-A and GIOVE-B L1 Open Service signals in space, producing the first reported computation of a double-difference carrier phase integer ambiguity resolution on the first two experimental Galileo satellites in orbit.
By Glen Gibbons
GPS manufacturers and users who employ so-called codeless and semi-codeless techniques based on exploiting the L2 carrier phase of the military P(Y)-code signals may want to comment on a new proposal to ensure that capability through 2020.
By Glen Gibbons
A screen in the Galileo control room displays the spectra of signals received from GIOVE-B shortly after the spacecraft began transmitting navigation signals. ESA photo.Europe’s second Galileo In-Orbit Validation Element (GIOVE-B) satellite began transmitting navigation signals on May 7, including the common GPS-Galileo civil signal MBOC (multiplexed binary offset carrier).
Built under a cooperation between the European Space Agency (ESA) and European Union (EU), GIOVE-B was launched April 27 from the Baikonur cosmodrome in Kazakhstan. The MBOC signal design will be used by the future GPS L1C broadcasts as well as the Galileo Open Service in accordance with an agreement drawn up in July 2007 between the EU and the United States.
Locked to an on-board passive hydrogen maser clock, the GIOVE-B signals will help improve positioning accuracy in challenging environments with multipath and interference as well as better penetration for indoor navigation.
By Inside GNSS
Applanix has announced the availability of a high altitude tactical mapping option for its DSS RapidOrtho system as well as the integration of the Trimble BD960 GNSS receiver module for its POS AV airborne position and orientation system.
With the GNSS module, POS AV products now support GPS L1/L2 and GLONASS L1/L2 processing, both in real-time and post-mission. The BD960 will also be able to receive and process the next-generation GPS L2C and L5 signals.
By Inside GNSS
Passage of a new regulation on Galileo sets the stage for the next phase of the €3.4-billion satellite navigation system’s development under a public procurement but leaves many details to be worked out among the key players: the European Commission (EC), the European Council, the European Parliament, and the European Space Agency (ESA).
Meeting in Strasbourg, France, the parliament adopted the measure on April 22 with 607 votes in favor, 36 votes against, and 8 abstentions.
“Things are looking up, finally, for the European GNSS programs,” Paul Verhoef, head of the Galileo unit in the EC’s Directorate-General for Transport and Energy, told an April 23 plenary session of the European Navigation Conference 2008 in Toulouse, France.
By Glen Gibbons
Nearly 30 years after the first launch of a GLONASS spacecraft, Russia is moving to add code division multiple access (CDMA) signals to the frequency division multiple access (FDMA) format that has set the world’s second-oldest global satellite navigation system apart from GPS and other systems under development.
A February 15, 2008, government decree on new GLONASS requirements calls for open CDMA signals with a binary offset carrier or BOC (2,2) signal structure centered at 1575.42 MHz and a BOC (4,4) signal centered at 1176.45 MHz — essentially corresponding to the center points of GPS signals at the L1 and L5 frequencies and nearby Galileo and Compass signals.
An additional GLONASS FDMA signal will be located at L3 frequencies (1197.648–1212.255 MHz), just below the GPS M-code at L2.
Russia will implement the new signals on the next-generation GLONASS-K satellites, with the first launch currently expected in late 2010 with flight testing the following year.
By Glen Gibbons
Close up view of the payload fairing of the Soyuz-Fregat launcher carrying ESA’s GIOVE-B satellite, on the launch pad in Baikonur, Kazakhstan, prior to the April 27, 2008, launch. ESA photo by S. CorvajaA new generation of GNSS signals will become available soon as Europe’s second Galileo In-Orbit Validation Element satellite (GIOVE-B) reached orbit, following successful launch on Sunday (April 27) from the Baikonur cosmodrome in Kazakhstan.
Riding a Soyuz/Fregat launcher, the 500-kilogram (1,100-pound) spacecraft lifted off at 12:16 a.m. Central European Summer Time (CEST). The Fregat upper stage performed a series of maneuvers to reach a circular orbit at an altitude of about 23,200 kilometers inclined at 56 degrees to the equator. The two solar panels that generate electricity to power the spacecraft deployed correctly and were fully operational by 5:28 CEST.
The European space Agency (ESA) operational schedule called for Galileo signals at three L-band frequencies to begin transmitting within seven to eight hours after reaching orbit, according to Giuseppe Viriglio, ESA’s director of telecommunications and navigation.
By Glen Gibbons
Communication/Navigation Outage Forecasting System (C/NOFS) satellite, General DynamicsOn Wednesday (April 16), a U.S. Air Force team successfully launched the Communication/Navigation Outage Forecasting System (C/NOFS), an experimental satellite designed to monitor the ionosphere and predict conditions that would disturb radio communications, including GNSS signals.
The satellite was ultimately deployed from a Pegasus rocket following an air launch from a Lockheed L-1011 that had taken off from Kwajalein Atoll in the mid-Pacific Ocean. First transmissions from the spacecraft were acquired shortly after it reached orbit.
By Glen Gibbons
The European GNSS Supervisory Authority (GSA) has released a new version of the provisional Galileo Open Service Signal-In-Space Interface Control Document (SIS ICD).
The new SIS ICD will enable developers to create products and applications that employ the Galileo system and signals. The new document is open for public consultation.
By Glen Gibbons
Spirent GSS8000 Constellation SimulatorUK-based Spirent Communications will introduce its new GSS8000 series of GNSS constellation simulators with GLONASS L2 capability at the Moscow International Satellite Forum April 7–8 and the European Navigation Conference–GNSS 2008 in Toulouse, France, April 22–25.
By Glen Gibbons
FY09 GPS Budget Request; FAA Line ItemThe GPS program has passed a milestone of sorts with the first allocation of funds from civil agencies to pay for a portion of the core GPS budget.
The Fiscal Year 2008 (FY08) budget for the U.S. Department of Transportation (DoT) sets aside $7.2 million as the first installment on the civil share of GPS modernization efforts, including the L1C signal that will be transmitted on the GPS Block III satellites and costs of monitoring the civil GPS signals in the modernized ground control segment (OCX). For the FY09 budget, the Bush administration has requested a $20.7 million allocation. The total five-year civil contribution (FY09-13) is expected to be more than $200 million.
By Glen Gibbons
Successful launch of a GPS Block IIR satellite on March 15 continues a U. S. Air Force initiative to bolster the nation’s GNSS constellation against anticipated failures of aging on-orbit spacecraft while improving system accuracy and accelerating the availability of new military signals.
An analysis of the condition of subsystems on GPS satellites in orbit last year indicated that up to nine GPS space vehicles (SVs) could fail in the near future, according to Col. David Madden, commander of the GPS Wing at the Space & Missile Systems Center, Los Angeles Air Force Base, California. “That’s what drove us down this path of launching five in one year,” said in a recent news conference.
By Glen Gibbons
