Global Navigation Satellite Systems Engineering, Policy, and Design
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
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.
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
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
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
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
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
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
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
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
GPS III satellite. Lockheed Martin illustrationThe U.S. Air Force has awarded Lockheed Martin a $21.5-million contract to provide a launch and checkout capability (LCC) to command and control all GPS III satellites from launch through early on-orbit testing.
By Inside GNSS
[Updated January 3, 2012] China released a long-awaited “test version” interface control document (ICD) for its Compass (BeiDou-2) GNSS system today (December 27, 2011). The 11-page publication covers its open B1 civil signal centered at 1561.098 MHz.
By Inside GNSS
GPS III pathfinder satellite testbed. Lockheed Martin photoThe Lockheed Martin team developing the U.S. Air Force’s next-generation GPS satellites (GPS Block III) has delivered the program’s pathfinder spacecraft to the company’s Denver, Colorado–area facility.
The program remains on schedule for a 2014 launch of the first Block III space vehicle (SV).
By Inside GNSS
