Global Navigation Satellite Systems Engineering, Policy, and Design
Francine Vannicola, Naval Research LaboratoryAs the forthcoming “Time and Navigation” opening next March at the Smithsonian National Air and Space Museum reminds us, modern navigation depends profoundly upon time — the more precise, accurate, and stable a navigation system’s timing is, the more precise, accurate, and stable its positioning capability.
By Inside GNSS
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Various designs of inertial/GNSS integrated navigation systems exist, with different architectures depending on the quality of sensors, the mission, the dynamics of the vehicle, and the non-linearity of the dynamics model, measurement model, or both.
By Inside GNSS
Javier Ventura-Traveset introduces Navipedia at the Munich Satellite Navigation Summit on March 14, 2012. He is responsible for managing Navipedia’s development as well as GNSS education activities for ESA.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.
In the last 30 years, satellite navigation applications have grown in number and kind, entire new systems have emerged, and existing systems have modernized.
By Inside GNSS
FIGURE 1: (top) Device without case. (bottom) Device with case.Long Term Evolution (LTE) technology in mobile communications, often called 4G, is making its way into a host of consumer devices. It started with data-only modules for Internet connectivity but quickly made its mark on smartphones, automotive communication, and embedded modules that provide fast and reliable wireless data connectivity to the machine-to-machine (M2M) market.
By Inside GNSS
Dr. Todd Walter, Stanford UniversityContrary to a widely held public impression, the elimination of GPS Selective Availability in 2000 did not take care of the needs that many users have for enhanced GNSS capabilities.
Indeed, various “augmentations” have been developed to meet the requirements of some applications for better accuracy, availability, or integrity (the assurance of the quality of a signal) than are available from GNSS signals in space.
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. NUMBER 3
Cape Canaveral, Florida USA
√ A third GPS IIF has arrived at Cape Canaveral and is being prepped for an October 4 morning launch. Two of the “follow-on” models with better clocks, trickster-foiling technology and more powerful signals are already up. Numbers four and five are waiting to go.
Return to main article: “Vector Delay Lock Loops”
By Inside GNSS
