GNSS (all systems)

March 14, 2011

GNSS Receiver Clocks

Q: Does the magnitude of the GNSS receiver clock offset matter?

A: It is well known that GNSS receiver clocks drift relative to the stable atomic time scale that ultimately defines a particular GNSS system in the first place. GNSS receiver manufacturers, however, try to limit the magnitude of the time offset to within some predefined range.

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By Inside GNSS

Integer Aperture Estimation

For the complete story, including figures, graphs, and images, please download the PDF of the article, above.

Integer carrier-phase ambiguity resolution is the key to fast and high-precision GNSS positioning and navigation. It is the process of resolving the unknown cycle ambiguities of the carrier-phase data as integers. Once this has been done successfully, the very precise carrier-phase data will act as pseudorange data, thus making very precise positioning and navigation possible.

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By Inside GNSS
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Coherent Integration Time Limits

Equation: signal variance for a “ring of scatterers” model

Indoor GNSS propagation environments are characterized by multiple reflected signal paths (multipath) terminating at the receiver. Consequently, the received signal’s amplitude, phase, and perceived angle of arrival attributes vary randomly as the receiver moves. This has created significant interest among receiver designers and manufacturers to develop powerful processing for GNSS handsets such that these can operate effectively in indoor faded environments.

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By Inside GNSS

The Civilian Battlefield

Figures 1 & 2

For the complete story, including figures, graphs, and images, please download the PDF of the article, above.

Growing dependence on GNSS for positioning, navigation, and timing (PNT) has raised a parallel concern about the potential risks of signal interference. The popular press has recently highlighted accounts of car thieves using GPS jammers, solar flares pumping out L-band radiation, and faulty television sets causing havoc to GPS receivers across an entire harbor.

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By Inside GNSS

GNSS Inside Mobile Phones

Figure 1 & Table 1

For the complete story, including figures, graphs, and images, please download the PDF of the article, above.

Recent years have seen GPS receivers built in as a standard feature in many consumer products. A growing number of mobile phones, personal navigation devices, netbooks and tablets are equipped with GPS receiver chips and navigation software that enable consumers to navigate from A to B or find their nearest coffee shop. According to Berg Insight, annual shipments of GPS-equipped mobile phones are estimated to reach 960 million devices in 2014.

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By Inside GNSS
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European Union GNSS Receiver Workshop

The Geospatial Building at the University of Nottingham

A two-day workshop on GNSS receivers will take place at the Geospatial Building at the University of Nottingham Innovation Park on April 14 and 15, 2011.

In addition to talks by GNSS experts, the workshop features product demonstrations, using the test facilitiies at GRACE, the GNSS Research and Applications Center of Excellence. These include GPS and Galileo full constellation Spirent simulator, signal record and replay devices and the roof-based fixed test track designed for dynamic research and testing.

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By Inside GNSS
March 11, 2011

European Union GNSS Receiver Workshop 2011

The 2011 EU GNSS Receiver Workshop will take place at the University of Nottingham’s Geospatial Building on April 14 and 15.

In addition to talks, the event features project demonstrations that make use of the GNSS Research and Applications Center of Excellence (GRACE) test facilities. These include a GPS and Galileo full constellation Spirent simulator, signal record and replay devices and the roof-based fixed test track designed for dynamic research and testing.

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By Inside GNSS

ASCE -SPAR Geomatics Continuing Education Seminar

Marriott Convention Center

The American Society of Civil Engineers will offer a day-long program on Monday, March 21 at SPAR International 2011 that will focus on real-time GNSS positioning and using the 3D Global Spatial Data Model

Bill Henning, senior geodesist for the National Geodetic Survey, will lead  the morning session. With more than 43 years of experience in all phases of surveying technology, he is helping to develop guidelines and support methodology for real time GNSS position with state, national, and international organizations.

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By Inside GNSS
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