Spring 2008

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Microelectromechanical system-based INS/GPS navigation designs are getting closer to the low cost, small size, and uninterrupted positioning solutions the automobile market demands. But MEMS inertial sensors are still too pricey for low-end civilian applications. Here’s a solution.

From a distance, it might look easy: the running of a GNSS system by a single country. But in the complex world of U.S. politics, it’s a wonder that anything gets worked out at all. And yet the National Space-Based Positioning,Navigation, and Timing initiative seems to be gaining some traction.

Receiver designers describe an innovative approach to signal tracking and processing issues associated with the binary offset carrier (BOC) modulation that will be used on modernized GPS and Galileo services. This radically different approach combines two independent estimates of the input signal’s time delay to create a single joint estimate that fully exploits the capabilities of BOC without running into problems of false lock.

Europe’s Galileo program is seeking to accelerate receiver technology development even as the spacea and ground segments of the system are being implemented. A group of companies have collaborated on development of a geodetic-grade Galileo-GPS receiver: ARTUS. The engineering team in charge of the project describes their work to date, including tests that tracked signals from China’s Compass system as well as GIOVE-A and GPS.

It’s a challenging world out there for user equipment, with ever more mobile applications and harsh environments. This article offers a roadmap for sensitive, robust and cost-effective receiver design.

Formation of the National Space-Based Positioning, Navigation, and Timing Executive Committee (PNT ExCom) three years ago occurred under circumstances as awkward as its interminable name.