Magazine Department

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Playing by the Rules of World Trade Law

The availability of several GNSSes promises advanced positioning, navigation, and timing services with higher availability and improved accuracy. According to a European GNSS Agency (GSA) market study, nearly 60 percent of receivers, chipsets, and modules already support at least two GNSS constellations, showing that multi-constellation is becoming a standard feature across all market segments. That development brings up questions of law and regulation that require careful handling by GNSS manufacturers, service providers, and policy makers.

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By Ingo Baumann
Software-Defined GNSS Simulator: A Step Forward

Software-Defined GNSS Simulator: A Step Forward

A few studies (by universities and industry) have shown the feasibility of simulation of real-time digital intermediate frequency (IF) signals based on a graphics processor unit (GPU). And a couple of articles have also demonstrated use of a universal software radio peripheral (USRP)–based software-defined radio (SDR) as a simulator (in playback mode) in real test environments.

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By Inside GNSS
First Position Fix with IRNSS

First Position Fix with IRNSS

Figure 1

The Indian Regional Navigation Satellite System (IRNSS) is an Indian Space Research Organisation (ISRO) initiative to build an independent satellite navigation system that provides precise position, velocity, and time (PVT) to users across the Indian region.

The primary objective of IRNSS is to achieve position accuracy of 20 meters (2σ) for dual-frequency users over India and the primary service area (a region extending to about 1,500 kilometers or 930 miles).

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By Inside GNSS
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Still Not a Thing, Part 2
May 26, 2015

Still Not a Thing, Part 2

One of the first feature articles I wrote as a newly minted GNSS magazine editor 26 years ago was about an advanced rail traffic management system based on GPS that Burlington Northern, with the help of Rockwell Collins, had designed and implemented.

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By Inside GNSS
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Are there special considerations for dealing with raw GNSS data?

Q: Are there special considerations for dealing with raw GNSS data?

A: Most GNSS users are only interested in position, velocity, and/or time (PVT) information provided by a receiver. In fact, most mass-market GNSS receivers (e.g., those in cell phones or in your vehicle) only provide PVT information along with some supporting data (such as the number of satellites tracked, dilution of precision, course over ground, and so forth).

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By Inside GNSS
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May 20, 2015

Estimating the Short-Term Stability of In-Orbit GNSS Clocks

Global navigation satellite systems provide position, velocity, and time (PVT) solutions to users whose receivers calculate position based on one-way ranging from satellites. As is well-understood, a key step in the positioning process involves a determination of the difference between the time of signal transmission identified in the satellite’s broadcast navigation message and the time of its reception by user equipment.

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By Inside GNSS
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Flying Blind
March 20, 2015

Flying Blind

It’s 10 p.m. somewhere over the vast oceans that comprise three-quarters of the Earth’s surface. Do you know where your airplane is?

Well, you could, but maybe you don’t.

The anniversary of the disappearance of Malaysia Airlines flight MH370 came and went in March with the fate of the Boeing 777 still unknown.

It didn’t have to happen.

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By Inside GNSS
How does a GNSS receiver estimate velocity?

How does a GNSS receiver estimate velocity?

Equations 1 – 11

Q: How does a GNSS receiver estimate velocity?

A: Stand-alone single-frequency GNSS receivers represent the largest slice of the commercial positioning market. Such receivers operate mainly in single point position (SPP) mode and estimate velocity either by differencing two consecutive positions (i.e., approximating the derivative of user position) or by using Doppler measurements related to user-satellite motion.

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By Inside GNSS
Seriously Seeking a Galileo Service Operator

Seriously Seeking a Galileo Service Operator

Carlo des Dorides, El?bieta Bie?kowska

Last January, the European GNSS Agency (GSA) announced a new invitation to tender for the role of Galileo service operator (GSOp). Speaking at the recent EU Space Policy Conference in Brussels, GSA Executive Director Carlo des Dorides called it the largest contract ever to be awarded under the Galileo program.

“It will shape the future of Galileo,” he said.

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By Peter Gutierrez
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