GNSS World Archives - Page 24 of 39 - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design

Why are carrier phase ambiguities integer?

It is well known that carrier phase ambiguities are integer values. Intuitively, this is hard to understand with a common counter-argument progressing along these lines: even if the receiver measures the instantaneous phase of the incoming signal (thus removing any fractional cycle component at the receiver end), the phase of the signal at the satellite cannot be guaranteed to be zero, so how can the ambiguity be integer?

In this article we explain why the carrier phase ambiguities are indeed integer.

By Inside GNSS

Frank van Diggelen: Riding the GNSS Wave

Running San Francisco Marathon, with daughter, Tanera. Note GPS watch.

SIDEBAR: Frank van Diggelen’s Compass Points

“It all traces back to my parents,” says Frank van Diggelen. “My father, Tromp van Diggelen, was a surfer. He taught me to surf and swim, in that order, when I was five. I was racing sailboats before I was 10, and there’s a lot of navigation there. Even when you’re just on a lake, the racing is all about reading the wind, understanding angles of convergence, velocity-made-good, and so on.”

By Inside GNSS

November 23, 2014

GNSS Hotspots | November 2014

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. Tariffs
Beijing, China

By Inside GNSS

November 22, 2014

Year 10

Every so often, anthropologists — and maybe a few mathematicians — have a field day puzzling over the origins of our positional base-10 numeral system.

Oh, not the historical origins themselves, the Hindu-Arabic innovations beginning in the 5th and 6th centuries. That’s all pretty much agreed.

No, I’m referring to the possible physiological inspirations, the readily visible digits at the ends of our limbs: 10 fingers, 10 toes.

Coincidence? Does nature have coincidents, or does it abhor them like vacuums — o horror vacui?

By Inside GNSS

November 17, 2014

Higher Aspirations for GNSS

GPS Space Service Volume (SSV) Requirements/Performance Parameters

New space missions such as the robotic repair and recovery of damaged or errant communication satellites may become possible with the aid of an emerging class of receivers that is able to use GPS signals for navigation in orbits thousands of kilometers above the middle Earth orbit (MEO) GPS constellation itself.

By Dee Ann Divis

EU and Russia: Lost in Space?

Russia’s involvement in the Ukraine crisis has turned much of public opinion in the West against that country, in particular souring the relationship between the European Union (EU) and Russia. And, while the ceasefire signed in September technically is still in force, the EU-Russia rift is far from smoothed over.

By Peter Gutierrez

What are the actual performances of GNSS positioning using smartphone technology?

Tables 1, 2, 3 & 4

Q: What are the actual performances of GNSS positioning using smartphone technology?

A: “Where I am?” is the typical question asked by a person when visiting a new city or unknown place. Knowing one’s own location is generally a basic necessity for people, both in indoors and outdoors.

By Inside GNSS

MEOSAR: New GNSS Role in Search & Rescue

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.

SIDEBAR: Locating a Distress Beacon Activated in Flight

By Inside GNSS

September 30, 2014

GNSS Hotspots | September 2014

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. STOP THE CAR!
Las Vegas, Nevada USA

By Inside GNSS

Alison Brown’s Compass Points

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Engineering Specialties

Systems design, algorithm design, systems integration and testing

GNSS Event that most signifies to you that GNSS has “arrived”.

Selective Availability being disabled to allow commercial users to benefit from full accuracy of GPS

Engineering Mentor

By Inside GNSS

September 27, 2014

A Learning Experience

My favorite bumper sticker this month: “Oh, no! Not another learning experience!”

After 20 years of putting together a European GNSS program, disappointment over the skewed launch of the first fully operational Galileo satellites is palpable and widely felt. For end users, it is uniformly bad news, and no system provider that sincerely wants to achieve interoperability and robustness in a system of GNSS systems can relish the European program’s current difficulties.

By Inside GNSS

September 24, 2014

OCX Program Restructured, Delayed Again

Editor’s Note: An exclusive interview with Gen. Hyten is available here with more details.

Details are emerging about another restructuring of the contract for the new GPS ground system, a deal that pushes completion of the project back another two years and recasts the remaining work to fit within the Air Force’s strained financial profile.

By Dee Ann Divis