March/April 2009

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The Igliniit (Trails) Project is a collaborative research project that brings together Inuit hunters from Clyde River, Nunavut, Canada, with researchers from Colorado, Calgary, and Carleton universities and undergraduate students from the University of Calgary to develop, test, and use an interactive GPS tracking system on snow machines and dog sleds. The system has a number of applications including tracking environmental conditions and changes over time, land/sea ice use studies, harvest studies, wildlife studies, travel safety, and search and rescue. This article describes the experiences of the participants over the first three years of the project.

Despite the best efforts of a Munich conference’s organizers to characterize the four programs as a competitive race, representatives of the world’s GNSS operators insist the it’s all about compatibility and interoperability — well, almost all . . . .

As GNSS receivers and applications spread throughout the world, a corresponding increase in the risk of spoofing appears likely — much as hacker attacks on websites have grown along with expansion of the Internet. This article describes the use of an angle-of-arrival countermeasure to thwart spoofing, by observing L1 carrier differences between multiple antennas referenced to a common oscillator.

A new tutorial series on the application of the popular Matlab software — a numerical computing environment and programming language — to process GPS observations. Each installment includes a discussion of a GPS-related computational task and a Matlab code that can be downloaded from an related website. In this issue, learn how to create a stereographic sky plot of satellite orbits and plot the time when satellites will be above a given local horizon. Details of the LAMBDA method are explained through a small numerical example.

Frank Takac, LEICA, discusses GLONASS ambiguity resolution in this regular column coordinated by contributing editor Mark Petovello

The continuing question is whether management of Galileo has changed sufficiently and soon enough to make a difference.

Aliens in Hawaii, the Alaskan Iditarod, Texas Hat Tricks, Chipset Champs, Munich Summit Notes, and Oops! in Space...