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Fractured GNSS Fairy Tales
September 14, 2012

Fractured GNSS Fairy Tales

Back in television’s halcyon days I should have been watching Donald Herbert explain science and technology on his Mr. Wizard programs.

But I was probably laughing my way through the Rocky & Bullwinkle Show instead, especially one of its mainstays, Fractured Fairy Tales — irreverent, yet revealing retellings of the Grimm Brothers’ homilies to human foibles.

And so I became a journalist instead of an engineer, hoping to fracture fallacies and received truths rather than oil shale.

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By Inside GNSS
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Vector Delay Lock Loops
September 3, 2012

Vector Delay Lock Loops

GNSS receivers determine their position and clock bias by measuring the arrival times of satellite signals. Delay lock loops (DLLs) are used in traditional receivers to measure the arrival times of the signals.

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By Inside GNSS
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GPS Civil Funding

GPS Civil Funding

The Federal Aviation Administration (FAA) has told those awaiting their slice of the GPS civil program budget that the funds are on the way.

The money, which is supposed to support that portion of the GPS program springing from the needs of civilian users, has been held up for months. In fact, as of late August — with less than 40 days left to go in the fiscal year — the money had not been transferred to either the military’s GPS Directorate or the National Coordination Office (NCO) for Space-Based Positioning, Navigation, and Timing (PNT).

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By Dee Ann Divis
Improving GNSS Attitude Determination

Improving GNSS Attitude Determination

This article describes an integration of a single-frequency GNSS, two-antenna heading system with low-cost inertial and magnetic field sensors in order to improve the availability and reliability of pure GNSS attitude determination. This method calculates a redundant attitude solution in an error-state Kalman filter using different sensor setups. As a result, the process of carrier phase ambiguity resolution accelerates.

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By Inside GNSS
Spoofs, Proofs & Jamming

Spoofs, Proofs & Jamming

TABLE 1. Spoofer antenna requirements for various hardened GPS signal types

“Here is Edward Bear, coming downstairs now, bump, bump, bump, on the back of his head, behind Christopher Robin. It is, as far as he knows, the only way of coming downstairs, but sometimes he feels that there really is another way, if only he could stop bumping for a moment and think of it. And then he feels that perhaps there isn’t.”
– A.A. Milne, Winnie-the-Pooh

Is our faith in the integrity and infallibility of the Global Positioning System misplaced or, perhaps, insufficiently grounded?

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By Inside GNSS
GNSS Hotspots | August 2012
August 27, 2012

GNSS Hotspots | August 2012

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. PAPER CUTS
Washington, Oklahoma, Ohio, Georgia, Pennsylvania
√ State transportation departments in Georgia, Pennsylvania, Oklahoma, and Ohio are printing fewer state highway maps, says the Associated Press. Washington did away with them entirely. Blame it on the double whammy of public sector budget cuts and smartphone, handheld, and in-car GPS. But there are lots of holdouts. As one Indiana man said, without a paper map, “You’re beholden to the GPS lady, you know?”

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By Inside GNSS
Interference & Jamming
July 27, 2012

Interference & Jamming

Phil Ward, Navward GPS Consulting

The threats just keep growing to a resource that hundreds of millions of people around the world have come to rely on for a myriad purposes.

GNSS is, after all, an RF technology, vulnerable in its own way to the kind of disruptive effects that turn an AM radio into a static-ridden howl as you drive under a powerline. And the radiated energy of signals arriving with from satellite sources tens of thousands of miles away are orders of magnitude weaker than those carrying the top 40 tunes broadcast by a local station.

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By Inside GNSS
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