Aerospace and Defense Archives - Page 44 of 56 - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design

March 26, 2012

UrsaNav Tests eLoran, LF Timing Potential

UrsaNav LF transmitter site for timing synchronization trials

Virginia-based engineering firm UrsaNav Inc. has begun transmitting a variety of low frequency (LF) test signals, including enhanced Loran (eLORAN), as part of a cooperative research and development agreement (CRADA) with the U.S. Coast Guard (USCG).

The test program include a comprehensive palette of signals that are being evaluated for their ability to provide a robust, wide-area, wireless precise timing alternative that can operate cooperatively with GNSS technology or autonomously during GNSS unavailability.

By Inside GNSS

March 22, 2012

SBIRS Decision Could Undermine Prospects for GPS Dual-Launch

SBIRS GEO-2 satellite in Baseline Integrated System Test (BIST-1). Lockheed Martin photo.

The Air Force is poised to forego putting nuclear detonation detection sensors on the Space-Based Infrared System (SBIRS) satellites, a decision that could complicate efforts to maintain the GPS system by hampering plans to launch multiple, lighter GPS satellites on a single rocket.

By Inside GNSS

March 21, 2012

Munich Summit Charts Progress of GPS, GLONASS, Galileo, Beidou GNSSes

Whenever the annual Munich Satellite Navigation Summit came around, some GNSS program was usually in the ascendant, while others had reversed direction or found themselves treading water. This year, perhaps for the first time, all four major providers had reason to celebrate as the event’s organizers cut the cake at their 10th birthday party.

By Inside GNSS

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March 20, 2012

Air Force Plans Shift to Fixed-Price Contract for GPS III

Gil Klinger, Deputy Assistant Secretary of Defense for Space and Intelligence. DoD photo.

As part of an effort to control costs, the U.S. Air Force will be shifting the GPS III program to a fixed-price contract, a Pentagon official told members of a House subcommittee recently.

By Inside GNSS

March 15, 2012

Peer-to-Peer Cooperative Positioning

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

One-Centimeter Accuracy with PPP

The navigation message has always been considered an inherent and essential feature of a global satellite navigation system. Its primary objective is to provide receivers with information on the errors of satellite clocks and parameters to compute the positions of satellites, as well as other parameters that help generate more accurate measurements.

By Inside GNSS

February 29, 2012

GPS Program Budget: A Lot, But Is It Enough?

The details of President Obama’s 2013 budget have been gradually filtering out and, in general, the GPS system and those programs closely linked to satellite navigation, have escaped deep cuts.

On the hardware side the White House has requested $58.2 for GPS IIF satellite procurement. According to Air Force budget documents, the plan is to then wrap up the total IIF procurement of 12 satellites with a request for $77.6 million in FY14 and $7.3 million in FY15.

By Inside GNSS

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February 18, 2012

President’s Budget Request Would Continue GPS Modernization

Following up on the “strategic guidance” on defense spending that the White House laid out last month, President Obama has proposed a Fiscal Year 2013 (FY13) budget that continues funding for GPS modernization efforts.

By Inside GNSS

January 13, 2012

Optimal Aligning of the Sums of GNSS Navigation Signals

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

Code Tracking and Pseudoranges

FIGURE 2: Pseudorange computation based on transmission. On the left side, the satellites are transmitting mes¬sages synchronously. On the right side, the four subframes are received asynchronously, due to the different propagation time. The TLM word is taken as a referene. The time differences ?i are computed on the basis of the relative arrival times of the front of the first bit of the TLM word.

Q: How can pseudorange measurements be generated from code tracking?

A: Every GNSS receiver processes the received signals to obtain an estimate of the propagation time of the signal from the satellites to the receiver. These propagation times are then expressed in meters to solve for the user position using trilateration.

By Inside GNSS

New Austerity Squeezes GPS as DoD Tightens Its Belt

Embracing the need for debt-driven discipline, the White House has revised its strategy for the nation’s defense, taking a more fiscally constrained approach that reduces the number of troops and future spending on defense systems.

The new plan, formally announced January 5, was already being put into effect last summer. “The strategic guidance was the compass by which we steered the budget review leading to the president’s budget for fiscal year ‘13 and the years thereafter,” Deputy Secretary of Defense Ashton B. Carter told reporters.

By Dee Ann Divis

Raytheon Gets New Contract for GPS OCX Launch and Checkout System

In the latest in a series of GPS modernization contracts, the U.S. Air Force Space and Missile Systems Center has awarded Raytheon Company a $27.4 million contract to develop a GPS Launch and Checkout System (LCS), which will provide early launch and checkout of GPS III satellites starting with the first GPS III launch in 2014.

By Inside GNSS

January 12, 2012

USAF Awards Lockheed Additional GPS IIIA Satellite Buy

The U.S. Air Force has awarded Lockheed Martin a $238 million contract for production of the third and fourth satellites in the next-generation GPS constellation, known as GPS III. The acquisition of the next two GPS IIIA satellites at one time will allow the Lockheed Martin-led team to maximize efficiencies in satellite manufacturing.

By Inside GNSS

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Aerospace and Defense

Satellite Development Advances as GPS Survives Budget Cuts, Light...

Galileo GNSS Through Children’s Eyes...

UrsaNav Tests eLoran, LF Timing Potential

SBIRS Decision Could Undermine Prospects for GPS Dual-Launch

Munich Summit Charts Progress of GPS, GLONASS, Galileo, Beidou GNSSes

Air Force Plans Shift to Fixed-Price Contract for GPS III

Peer-to-Peer Cooperative Positioning

One-Centimeter Accuracy with PPP

GPS Program Budget: A Lot, But Is It Enough?

President’s Budget Request Would Continue GPS Modernization

Optimal Aligning of the Sums of GNSS Navigation Signals

Code Tracking and Pseudoranges

New Austerity Squeezes GPS as DoD Tightens Its Belt

Raytheon Gets New Contract for GPS OCX Launch and Checkout System

USAF Awards Lockheed Additional GPS IIIA Satellite Buy