system infrastructure/technology Archives - Page 6 of 12 - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design

August 27, 2009

NOAA, Japan Establish QZSS Ground Station in Guam

Officials from the National Oceanic and Atmospheric Administration and the Japan Aerospace Exploration Agency (JAXA) have unveiled a new ground station in Guam that will track spacecraft from JAXA’s upcoming Quasi-Zenith Satellite System (QZSS).

Designed to work seamlessly with the U.S. Global Positioning System, QZSS is a space-based augmentation system (SBAS) being developed by JAXA to improve navigation satellite coverage over Japan and surrounding areas. The first QZSS satellite is expected to launch in 2010.

By Inside GNSS

August 19, 2009

Russia Building Out GLONASS Monitoring Network, Augmentation System

GLONASS-K spacecraft (artist’s illustration)

With a nearly restored and modernizing GLONASS system beginning to make inroads into mass market products and services, Russia has revealed plans to build out a space-based augmentation system (SBAS) and establish its first ground monitoring stations outside the Russian territory.

In a July 30 presentation at an International Committee on GNSS (ICG) working group on interoperability, Dmitry Marareskul, head of the onboard satellite navigation sector of Information Satellite System Reshetnev Corporation in Zheleznogorsk, revealed Russia’s plans to expand its network of GLONASS monitoring and measuring stations to include sites in Australia, Cuba, and South America.

By Inside GNSS

August 6, 2009

Upcoming Block IIR-(21)M Launch Wraps Up Generation of GPS Satellites

The scheduled August 17 launch of GPS satellite IIR-(21)M — also known by its space vehicle number SVN50 — will mark the end of a couple of eras: the final launch of the Lockheed Martin–built replenishment generation (Block IIR) of GPS satellites and the last Air Force launch using the Delta II rocket.

Notably, SVN50 will not have a payload connected to the J2 reserve auxiliary payload port that proved problematical with the L5 demonstration payload on the previous GPS satellite, SVN49, and possibly on other Block IIR/IIRMs.

By Inside GNSS

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July 31, 2009

GPS SVN49 Signal Anomaly: USAF Ponders Plan B

(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

July 23, 2009

U.S. House of Representatives Trims $97 Million from OCX Budget, Cites Contract Delays

(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

July 18, 2009

GPS Signal Anomalies: Is SVN49 Just the Tip of the Iceberg?

Block IIR Satellite L-Band Transmitter Array of 12 Helical Antennas. Lockheed Martin photo.

After GPS Wing engineers and contractors figure out how to solve the elevation-dependent signal anomalies on the latest GPS satellite — Space Vehicle Number 49 (SVN49), they may want to take a look at another nine Block IIR and IIR-M spacecraft that European scientists say exhibit similar, but less severe, behavior.

In an article that will appear in the July/August issue of Inside GNSS, Tim Springer and Florian Dilssner, GNSS engineers in the Navigation Support Office of the European Space Operations Center (ESOC), described the effects of the anomaly as well as the U.S. Air Force’s initial attempts to solve the problem by altering the broadcast satellite orbital positions and time. A version of the article was posted June 25 on the magazine’s website.

By Inside GNSS

July 17, 2009

U.S. Access to Europe’s Galileo Program Markets Subject of Trade Rep Report

Comments submitted to the Office of the U.S. Trade Representative (USTR) suggest that the Galileo program is finally nearing a decision on commercial use of specifications for its Open Service (OS), but U.S. officials remain concerned that this nation’s equipment manufacturers not be placed at a competitive disadvantage. Meanwhile, Galileo simulators appear to finally be reaching receiver manufacturers, despite the absence of official approval.

By Inside GNSS

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July 16, 2009

iGPS Program Reaches Two Milestones

Iridium Satellite LLC (Iridium) and Boeing have achieved two major milestones to further develop and demonstrate capability enhancements to the High Integrity Global Positioning System (iGPS) program for the U.S. Naval Research Laboratory.

By Inside GNSS

June 25, 2009

Saving GPS SVN49: Tweaking Satellite Ephemerides and Time

When GPS reference receivers at the European Space Operations Center (ESOC) detected a 150-meter error in the broadcast ephemerides (orbital position) for the latest GPS satellite — Space Vehicle Number 49 or SVN49 — scientists there assumed that a problem had arisen with the spacecraft’s navigation payload.

After all, coupled with an apparent 500-nanosecond clock error, the ephemerides could produce many kilometers of errors for navigation receivers.

By Inside GNSS

May 25, 2009

GAO Report on GPS Satellite Constellation Status: The Pushback

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

May 21, 2009

GPS III Passes Preliminary Design Review

GPS IIIA. Lockheed Martin graphic

The Lockheed Martin team developing the next-generation GPS III satellites has successfully completed a major program milestone, the preliminary design review (PDR) conducted by the U.S. Air Force’s GPS Wing.

Underlining the importance placed on meeting a 2014 first-launch schedule, nearly 150 representatives from the GPS Wing and user communities, including representatives from the Department of Defense, the Joint Chiefs of Staff, Air Force Space Command, the Department of Transportation, and the Federal Aviation Agency participated in the four-day Space Vehicle PDR at Lockheed Martin Space Systems facilities in Newtown, Pennsylvania.

By Inside GNSS

Obama 2010 GPS Budget Calls for $1 Billion+

The president’s proposed Fiscal Year 2010 (FY10) budget would provide more than $1 billion for GPS and related U.S. space-based positioning, navigation, and timing (PNT) programs.

By Inside GNSS