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Columns and Editorials

November 21, 2011

GNSS Hotspots

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!

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By Inside GNSS
November 16, 2011

Oh No! Not LightSquared Again!

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.

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By Inside GNSS

Network RTK and Reference Station Configuration

FIGURE 1: The three different GNSS networks designed for the experiments and the rover site

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.

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By Inside GNSS

LightSquared: Who Pays for GPS Receiver Fixes Yet to be Devised?

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.

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By Dee Ann Divis
September 14, 2011

GNSS Hotspots

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
Santa Cruz, California USA
√ First, get the cougar on the treadmill . . . that’s what UC Santa Cruz researchers did to measure baseline behavior and design a tool that tells what puma concolor do every minute. Their super-advanced CARNIVORE collar uses GNSS and a 3-axis accelerometer to create a 24-hour diary of the wild life.

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By Inside GNSS
September 13, 2011

Worst GPS President Ever?

First, let’s review the record of presidential leadership in GPS.

In 1983, following the shooting down of an errant Korean airliner over Soviet airspace, President Ronald Reagan ordered the U.S. Air Force to make GPS available for civilian use so that such navigational errors could be avoided in the future.

George H. W. Bush was commander in chief in 1991 during the first Persian Gulf when GPS helped coalition troops throw the so-called “left hook” by navigating through the desert around entrenched Iraqi troops in Kuwait.

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By Inside GNSS

The Differences in Differencing

Equation 1

Q: How does measurement differencing affect my computed position?

A: The short answer is, “That depends.”

Standalone, or undifferenced, measurements obviously produce the poorest positioning performance. However, how we proceed from this most basic data processing approach may affect the computed solution. In this article, we look at the details of why this occurs.

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By Inside GNSS