Global Navigation Satellite Systems Engineering, Policy, and Design
The firefight between LightSquared and the GPS community has sparked regulatory brush fires around Washington with the Federal Communications Commission (FCC), Congress, a half dozen executive agencies, and numerous companies moving to address a new and likely larger battle over receiver standards, radio frequency spectrum efficiency, and RF spectrum protection.
By Dee Ann Divis
Q: What is Coarse Time Positioning and how does it work?
A: Coarse time positioning is used to provide a position fix using inaccurate time information when tracking sufficiently weak GNSS signals such that the navigation message cannot be extracted reliably. This article presents the key aspects of coarse positioning, including some of its challenges. To start, however, we begin by looking at the role of time within a GNSS receiver.
By Inside GNSS
Return to main article: "Code Tracking and Pseudoranges"
By Inside GNSS
Why Washington continues to talk about deficits while the country is talking about jobs and foreclosures is kind of a mystery, but let’s play along.
Following the failure of Congress’s would-be budget-cutting committee that wasn’t so super, the Department of Defense is facing about $500 billion in mandatory cuts over the next 10 years.
By Dee Ann Divis
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
Return to main article: “Network RTK and Reference Station Configuration”
By Inside GNSS
