Columns and Editorials

A Search for Spectrum
August 17, 2010

A Search for Spectrum

In recent years, researchers have explored possible new allocations for Radio Determination Satellite Service (RDSS) and Radio Navigation Satellite Service (RNSS) spectrum from a regulatory point of view. These studies have mainly discussed S-band and C-band in addition to L-band.

The International Telecommunications Union (ITU) Radio Regulations define RNSS as a subset of RDSS. Although the allocations are differentiated — RDSS usually has a paired uplink — both can actually be used for satellite navigation.

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By Inside GNSS
A Fully Digital Model for Kalman Filters

A Fully Digital Model for Kalman Filters

Q: Is it possible to define a fully digital state model for Kalman filtering?

A: The Kalman filter is a mathematical method, purpose of which is to process noisy measurements in order to obtain an estimate of some relevant parameters of a system. It represents a valuable tool in the GNSS area, with some of its main applications related to the computation of the user position/velocity/time (PVT) solution and to the integration of GNSS receivers with an inertial navigation system (INS) or other sensors.

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By Inside GNSS
GNSS Hotspots | July 2010
July 23, 2010

GNSS Hotspots | July 2010

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. EARTHQUAKE!
Seattle, Washington USA
√ Want to know where an earthquake will occur and how big it will be? The Pacific Northwest Geodetic Array (PANGA) geodesy lab can tell you. They use 350 continuously operating high-precision GPS receivers and can analyze and share quake data in less than a minute. (Fact: A megaquake is likely 50 miles from Seattle).

PANGA’s website

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By Inside GNSS
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Interesting. Too Interesting?
July 21, 2010

Interesting. Too Interesting?

In the world of GNSS we usually think of more as better. More systems, more satellites, more signals — all contribute to greater availability of robust positioning, navigation, and timing.

Certainly that was the mood at the June meeting of the Asia-Pacific Economic Cooperation — GNSS Implementation Team (APEC-GIT) in Seattle, Washington.

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By Inside GNSS
Generating Carrier Phase Measurements
June 22, 2010

Generating Carrier Phase Measurements

Q: What is the carrier phase measurement? How is it generated in GNSS receivers?

A: Simply put, the carrier phase measurement is a measure of the range between a satellite and receiver expressed in units of cycles of the carrier frequency. This measurement can be made with very high precision (of the order of millimeters), but the whole number of cycles between satellite and receiver is not measurable.

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By Inside GNSS
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GNSS Hotspots | June 2010
June 1, 2010

GNSS Hotspots | June 2010

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. HERE KITTY, KITTY
Nassau County,New York USA
√ IEEE Spectrum blogger Mark Spezio attached a GPS logger to his wandering cat, whose complex journeys centered on a mouse-hunting paradise: Nassau County Storm Water Basin Storage Area. The cat was amazed to see Mark show up at his secret hideaway.

See cat and maps here 

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By Inside GNSS
Deselecting Unavailability
May 31, 2010

Deselecting Unavailability

Only a decade ago, but a world away: 2000.

The last year of the old century that everyone thought was the first of the new.

When flying was still a delight, rather than a worrisome bother.

When the expected — a global Y2K bug–bitten IT meltdown — didn’t happen, and the much-anticipated but still-unexpected did: the United States turned off GPS selective availability.

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By Inside GNSS
Human Engineering
October 16, 2007

Human Engineering

Human Engineering is an occasional feature that profiles GNSS engineers in industry, academia, the military and government.

Want to know someone’s favorite equation? Or how they discovered satellite navigation in their own careers? The popular notions about GNSS that annoy them most?

This is the place to look.

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By Inside GNSS
GNSS Solutions
October 7, 2007

GNSS Solutions

“GNSS Solutions” is a regular column featuring questions and answers about technical aspects of GNSS.

Readers are invited to send their questions to columnist Mark Petovello, Department of Geomatics Engineering, University of Calgary in Alberta, Canada. He will find experts to answer those questions, which will be published in Inside GNSS.

Dr. Petovello is a professor at the university. He has been actively involved in many aspects of positioning and navigation since 1997.

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By Inside GNSS
Working Papers

Working Papers

This regular Inside GNSS column explores the technical and scientific themes that underpin Global Navigation Satellite System programs and applications.

It features analyses and discussions by engineers and researchers on topics ranging from GNSS interoperability to preferred technologies for GNSS receivers to antispoofing tools for GNSS signals.

The column is coordinated by Prof. Dr.-Ing Günter Hein, head of Galileo Operations and Evolution Department of the European Space Agency.

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By Inside GNSS
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