Global Navigation Satellite Systems Engineering, Policy, and Design
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
One of 12 magnetograms recorded at Greenwich Observatory during the Great Geomagnetic Storm of 1859
1996 soccer game in the Midwest, (Rick Dikeman image)
Nouméa ground station after the flood
A pencil and a coffee cup show the size of NASA’s teeny tiny PhoneSat
Bonus Hotspot: Naro Tartaruga AUV
Pacific lamprey spawning (photo by Jeremy Monroe, Fresh Waters Illustrated)
“Return of the Bucentaurn to the Molo on Ascension Day”, by (Giovanni Antonio Canal) Canaletto
The U.S. Naval Observatory Alternate Master Clock at 2nd Space Operations Squadron, Schriever AFB in Colorado. This photo was taken in January, 2006 during the addition of a leap second. The USNO master clocks control GPS timing. They are accurate to within one second every 20 million years (Satellites are so picky! Humans, on the other hand, just want to know if we’re too late for lunch) USAF photo by A1C Jason Ridder. 
Detail of Compass/ BeiDou2 system diagram
Hotspot 6: Beluga A300 600ST
1. Portland, Oregon and Los Angeles, California USA
TWINS!
Please.
Please. Please. Please.
Can we please talk about something besides LightSquared?
Not yet? You mean, they are still here?
And we have so many other GNSS-related topics that deserve comment:
Some peculiar cuts in civil GPS funds and GPS III budgets being proposed by congressional committees.
A re-examination — aka analysis of alternatives — of GPS and PNT options in general. Space weather and an impending solar max. Warrantless GPS-aided tracking before the Supreme Court.
By Inside GNSS
Q: What effect does network size have on NRTK positioning?
A: Network real-time kinematic (NRTK) positioning is nowadays a very common practice, not only in academia but also in the professional world. In the last 10 years, several networks of continuous operating reference stations (CORSs) were created to support users. These networks offer real-time services for NRTK positioning, providing centimeter-level positioning accuracy with an average distance of 25–35 kilometers between the reference stations.
By Inside GNSS
With more testing on the horizon and a potentially alarming homeland security report about to be released, LightSquared’s efforts to begin work on its proposed wireless broadband service are stuck in the procedural mud.
The delays, which are never good for a commercial company, are piling up just as the firm’s coffers are thinning and need to be replenished with a new round of fund raising.
By Dee Ann Divis
