Design of a GPS Tracking ASIC for Space Applications

Don M. Gruenbacher, Kim Strohbehn, Will S. Devereux, Robert J. Heins, Lloyd A. Linstrom, and Glenn T. Moore

Abstract:	A GPS receiver ASIC designed for spaceborne applications is described. The GPS Tracking ASIC, or GTA, is designed to perform the basic correlation functions of a GPS receiver as well as several other functions and capabilities. The GTA includes twelve tracking channels, each of which contains two numerically controlled oscillators, a C/A code generator, carrier and code mixing, and accumulators. Each tracking channel on the GTA may be configured to process input data from any of four down converter inputs. The interface for each down converter also allows different data input representations. Multiple GTA's may be used in parallel to allow the processing of integer multiples of 12 channels. A microprocessor interface allows control of all aspects of the GTA as well as reading back data to be used in closing the tracking loops of the GPS receiver. One other aspect of the GTA is the generation of various clocks and interrupts based on a system clock. The GTA was designed in VHDL using Synopsys design and verification tools. It is implemented on a Honeywell HX2300r Silicon on Insulator (SOI) gate array, with a core supply voltage of 3.3 volts and a input/output supply voltage of 5 volts for interfacing. The 200,000 gate GTA dissipates less than 150 mW. This paper discusses features of the GTA, methods of implementation, results, and the direction of future generations of the GTA.
Published in:	Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999) September 14 - 17, 1999 Nashville, TN
Pages:	895 - 900
Cite this article:	Gruenbacher, Don M., Strohbehn, Kim, Devereux, Will S., Heins, Robert J., Linstrom, Lloyd A., Moore, Glenn T., "Design of a GPS Tracking ASIC for Space Applications," Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999), Nashville, TN, September 1999, pp. 895-900.
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