July/August 2008

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Growing the demand for mass-market LBS applications will require more signal resources incorporated into common data formats and message protocols - in a word: standardization.

Real-world scenarios put together by the U.S. Defense Department's lead GPS test organization help active military, defense contractors, and civil agencies test their equipment against the growing threat of unwanted interference.

Seamless, continuous navigation capability keeps getting closer. Many efforts use inertial technology to compensate when GPS signals are blocked. An Australian team describe their progress in creating a low-cost FPGA-based sensor-fusion unit built on an embedded processor.

From time to time, the words in the column title have  been a metaphor for the U.S. GPS program, and could end up as a permanent description of the state of our national public infrastructure - deferred maintenance.

What is multiple reference station RTK and what are its advantages and disadvantages?

The Naval Research Lab's GPS clock master Ron Beard dwells in the realm of the nanosecond. That's one billionth of a second, a virtually incomprehensible unit of time even for geeks. But the seamless operation of our cell phones, power grid, banking, and other GNSS-driven technologies depends on that degree of precision.

Tracking low-power spread spectrum GNSS signals inside buildings is complicated by the effects of various architectures and building materials on signals passing through them. In this final installment of a three-part series, the authors identify, measure, and model some of the key variables affecting the indoor performance of the actual Galileo signal in space.