Aerospace and Defense Archives - Page 37 of 54 - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design

March 5, 2014

DoT Agrees to GPS CNAV Test Plan, Seeks Public Comment

Message Type 30: satellite clock data, and corrections for ionospheric and group delay. From IS–GPS–200G

In a Federal Register notice issued today (March 5, 2014), the U.S. Department of Transportation (DoT) invited public comments on U.S. Air Force plans to implement preoperational L2C and L5 civil navigation (CNAV) messages on GPS Block IIR-M and IIF satellites next month.

By Inside GNSS

February 28, 2014

Change in GPS IIR/IIR-M Satellite Battery Charging Will Extend Mission Life

Modifications in the battery charging protocol of on-orbit GPS satellites are expected to substantially extend the mission life of the spacecraft — a particularly timely development as technical and financial difficulties have raised doubts about keeping the system’s next-generation Block III satellites on schedule for launch readiness.

By Inside GNSS

February 14, 2014

House Committee Moves to Block Loran-C Teardowns

Lawmakers overseeing the Coast Guard approved language this week that would stop the agency from dismantling facilities needed for eLoran, a proposed system that has gained wide support as a backup in case GPS signals are jammed, blocked, spoofed, or otherwise rendered unusable.

In “markups” or adjustments to language in the FY 2015 Coast Guard authorization bill, a House transportation subcommittee proposes to halt the tearing down of stations in the Coast Guard’s old Loran-C navigation system, which was turned off in 2010.

By Inside GNSS

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January 31, 2014

GPS IIFs Back on Launch Manifest

The fifth GPS Block IIF satellites is scheduled for launch from Cape Canaveral on February 20 after concerns regarding a 2012 launch anomaly led the Air Force to scrub a planned launch last fall. A Delta IV M+ will carry the spacecraft into orbit.

Additional GPS IIF launches this year are tentatively set for May (Delta IV M+) and July (Atlas V rocket). The last GPS launch (GPS IIF-4) took place on May 13, 2013.

By Inside GNSS

FY14 Budget Pares GPS Appropriations

The GPS program sustained a cut of more than six percent from the levels in the president’s proposed budget for Fiscal Year 2014 (FY14), increasing the likelihood that the Next Generation Operational Control System (OCX) will be delayed and putting pressure on budgets in future years to make up for cuts to modernization efforts.

By Inside GNSS

January 22, 2014

DoT Opposes Early Start for Navigation Messages on New Civil GPS Signals

John Porcari

The U.S. Department of Transportation (DoT) is asking the Air Force to cancel its plan to add navigation data to two key civil GPS signals this year, saying they are concerned that the approach and “nonstandard engineering tools” military officials plan to use could put GPS users at risk.

By Inside GNSS

January 19, 2014

Marc Weiss

Weiss at the helm during sailboat outing to San Juan Islands (top), Marc Weiss and wife, Pam (bottom)

SIDEBAR: Marc Weiss’ Compass Points

In a career spanning nearly the entire history of GNSS-enhanced metrology, Marc Weiss has been a key participant in projects that laid the foundation for accurate synchronization of atomic clocks around the world.

By Inside GNSS

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November 18, 2013

Finding the Right Algorithm

Receiver (on the right) and antenna (on the left) comprised the on-board unit used in both data collections

Working Papers explore the technical and scientific themes that underpin GNSS programs and applications. This regular column is coordinated by Prof. Dr.-Ing. Günter Hein, head of Europe’s Galileo Operations and Evolution.

By Inside GNSS

OCX and GPS Cybersecurity

The GPS program is setting a new space-system standard for cyberdefense, and now the federal government is creating a framework to help operators of critical infrastructure that largely rely on GPS to do the same.

The need to raise the bar is clear. Malicious coders, often backed by hostile nation-states or criminal organizations, are using automated tools to continuously probe for weaknesses:

By Dee Ann Divis

October 31, 2013

Budget Battle: GPS Program Funding Appears Solid

The GPS program appears well positioned to weather another round of budget cuts, although some contractors that support the program may not be so fortunate.

“I would expect GPS will be relatively protected (with) continued investment and modernization of the satellite constellation.” said Robert Levinson, a senior defense analyst for Bloomberg Government during an October 28 briefing.

“GPS is in fairly good shape,” confirmed an expert familiar with the Air Force’s budget.

By Inside GNSS

September 17, 2013

Bring Real-World GNSS Satellite Signals Back to the Lab . . . with More Detail Than Ever

Spirent GSS6425 Record and Playback System

Spirent Communications has unveiled a new system for recording real-world GNSS RF signals and replaying them in the lab.

“Record and Replay” is popular as a more rigorous — and, crucially, repeatable — approach to GPS and GNSS testing than using live signals in real time, where satellite positions and atmospheric conditions are constantly changing.

By Inside GNSS

September 14, 2013

GAO Report: More Research Needed to Determine GPS Program Changes

Air Force officials should get more cost and user information and determine how many GPS satellites they will support before making decisions about revamping the navigation system, the Government Accountability Office (GAO) has told Congress.

Although an Air Force report about program options was “a good starting point, more information on key cost drivers and cost estimates, and broader input from stakeholders would help guide future investment decisions,” the GAO wrote in an assessment of the defense agency’s analysis.

By Inside GNSS

September 13, 2013

Building a BeiDou Simulator

BeiDou-2 Is Born
The year before the main release, China surprised the global community when it published just a test version of the promised ICD for the BeiDou-2 B1 open signal. In this document, the modulation scheme for the signal was confirmed and the pseudorandom code generator for the ranging signal was described.

By Inside GNSS

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Aerospace and Defense

Who’s Your Daddy?...

FY15 Budget: GPS III Procurement to Slow, Dual-Launch Funding Cut...

DoT Agrees to GPS CNAV Test Plan, Seeks Public Comment

Change in GPS IIR/IIR-M Satellite Battery Charging Will Extend Mission Life

House Committee Moves to Block Loran-C Teardowns

GPS IIFs Back on Launch Manifest

FY14 Budget Pares GPS Appropriations

DoT Opposes Early Start for Navigation Messages on New Civil GPS Signals

Marc Weiss

Finding the Right Algorithm

OCX and GPS Cybersecurity

Budget Battle: GPS Program Funding Appears Solid

Bring Real-World GNSS Satellite Signals Back to the Lab . . . with More Detail Than Ever

GAO Report: More Research Needed to Determine GPS Program Changes

Building a BeiDou Simulator