Global Navigation Satellite Systems Engineering, Policy, and Design
My history with GPS began during the time of the “Cold War” in what was then Czechoslovakia. In 1975, the ION Journal of Navigation was the only information available to me. Despite that, my team at the Czech Technical University developed a GPS receiver and measured the position of our faculty in 1984. In those relatively isolated years, we gained a good deal of experience with GPS signals.
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As I pack my bags for the damply enticing venue of Savannah, Georgia, I’m reminded that this is my 21st consecutive journey to an ION GNSS conference. And the number 21 still has a lingering resonance as the age of majority, the harbinger of having reached adulthood — if not maturity.
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An increasingly likely $97.4-million cut in the GPS OCX budget for fiscal year 2010 (FY10) would slow down work on modernization of the operational control segment, but the Air Force would try to recoup any reduction in the FY11 budget.
Meanwhile, technical problems that have delayed development of the follow-on generation of Block IIF satellites are largely resolved and a first launch is expected in May 2010.
By Inside GNSS
(Updated August 4, 2009)
A GPS community consensus is emerging that the initial proposal for mitigating the L1 signal anomaly causing elevation-dependent ranging errors on the SVN49 satellite isn’t the best approach.
By Inside GNSS
The recent GAO report and Government Oversight subcommittee hearing on GPS sustainability generated more heat than light, with some major news media outlets leaving the impression that the sky (or at least GPS satellites) would soon be falling.
Perhaps the only silver lining in the ensuing Chicken Little phenomenon was the crude measure it provided of just how familiar (but not necessarily knowledgeable) private citizens have become with GPS.
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(Updated 11 a.m. (PDT), includes additional details from the GPS Wing)
A $97.4-million reduction in the GPS program made by the U.S. House of Representatives would affect the modernization program for the operational control segment (OCX), not the GPS III satellite budget as reported earlier.
In adopting the action of its appropriations committee, the full House approved H.R. 3326, the Department of Defense (DoD) Fiscal Year 2010 (FY10) budget, on July 30. The bill was referred to the Senate Appropriations Committee on August 3. In its report on the bill, the House committee said it made the cuts because of contract delays in the OCX program.
By Inside GNSS
The Indian Space Research Organization (ISRO) has awarded a new $82 million contract to Raytheon Company to modernize the Indian air navigation system.
Raytheon will build the ground stations for the GPS-Aided Geosynchronous Augmented Navigation System (GAGAN), and the Indian Space Research Organization will provide the space segment and additional ground equipment. GAGAN will provide satellite-based navigation for civil aviation over Indian airspace and adjoining areas in south and east Asia.
By Inside GNSS
Pendulum Instruments, Stockholm, Sweden, has introduced four new options for the company’s GPS-12 Portable Frequency Standard family.
First released in 2006, the GPS-12R, a portable GPS controlled rubidium Frequency Standard with battery backup power, supplies a variety of standard frequencies for general metrology (1, 5, and 10 MHz), base station test (13 MHz) and telecom (E1/T1 clock/data).
By Inside GNSS
Figure 1
The downloadable PDF (above) contains bonus material not available in the print edition. Appendices and other information on this subject is available at the bottom of the page.
The current version of the master GPS Interface Specification document (IS-GPS-200 Rev D March 2006) contains a new dual-frequency ionosphere correction algorithm that is to be used with the modernized GPS space vehicles (SVs) and their next-generation modernized GPS signals.
René Oosterlinck, ESA director of the Galileo Program and Navigation-related Activities (center), and Jean-Yves Le Gall, chairman and CEO Arianespace (left), sign the Galileo In-Orbit Validation Launch Services Contract in the ESA Pavilion at the Paris Air Show, Le Bourget. Paul Verhoef, programme manager of EU Satellite Navigation Programs at the European Commission. ESA photo — S. Corvaja, 2009On June 15, the European Space Agency (ESA) signed contracts for launch services on the Galileo in-orbit validation (IOV) satellites as well as two additional contracts for “long lead items” needed to build the full operational capability (FOC) Galileo constellation of satellites.
The first contract, with Arianespace, will provide launch services for the four IOV Galileo satellites that will be placed in orbit by the end of 2010. Two Soyuz rockets, each carrying two Galileo spacecraft, will launch from Europe’s Spaceport in French Guiana.
By Inside GNSS
DAGR 2008. Rockwell Collins imageDevelopment and acquisition of military GPS user equipment (MGUE) are taking on new dimensions across the board — institutionally, procedurally, and technologically.
Along the way, the changes could redefine relationships within the Department of Defense (DoD) and between the agency and industry.
At the agency level, a proposal is forthcoming to “stand up” a positioning, navigation, and timing (PNT) user equipment joint program office (JPO) that would incorporate UE responsibilities (and budgets) now exercised by the GPS Wing (GPSW).
By Inside GNSS
Two weeks after a Government Accountability Office (GAO) report warned of potential gaps in the GPS satellite constellation, reassurances from Department of Defense (DoD), U.S. Air Force, GPS program officials, and industry are slowly restoring calm to an anxious public.
Coupled with a May 7 congressional hearing (and subsequent media coverage) that fanned the flames, the report described scenarios — for instance a two-year setback in launching the first GPS III spacecraft — that could lead to deterioration in the quality of GPS service due to delays in building new generations of satellites and past program management problems. The news coverage drew primarily on the GAO report and prepared statements presented at the hearing and not on the much more interesting dialog with subcommittee members captured on video or on the assumptions and methodology underlying the constellation analysis.
By Inside GNSS
Mike Shaw, NCO Executive DirectorA June 18 meeting of the National Space-Based Positioning, Navigation, and Timing (PNT) Executive Committee (ExCom) will bring together leaders of the Obama administration in the key interagency setting for GPS issues.
Established under a 2004 National Presidential Security Directive, the ExCom advises and coordinates federal departments and agencies on matters concerning the Global Positioning System and related systems. The deputy secretaries of defense and transportation and co-chair the committee, which includes equivalent-level members from seven other federal agencies.
By Inside GNSS
