200907 July/August 2009 Archives - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design

200907 July/August 2009

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.

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By Inside GNSS
June 29, 2009

GPS Wing Seeks Manufacturer, User Feedback on SVN49 Signal Anomaly, Solution

GPS satellite L-band antenna elements

The GPS Wing is reaching out to receiver manufacturers and the user community to gather comments on the SVN49 signal anomaly and the Air Force’s provisional solution to the problem.

Despite earlier news reports suggesting that the problem, which has kept the latest GPS satellite from being declared operational, was on its way to being solved, a GPS Wing spokesperson characterized the remedy of altering the satellite’s broadcast orbital position (ephemeris) and time as only a “partial fix.” Indeed, high-precision dual-frequency users, such as those in the International GNSS Service, may continue to encounter difficulties in handling the SVN49 signal.

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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.

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By Inside GNSS
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June 4, 2009

Changes in Store for U.S. Military GPS Equipment Development and Acquisition

DAGR 2008. Rockwell Collins image

Development 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).

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By Inside GNSS