Block Acquisition of Weak GPS Signals in a Software Receiver

Mark L. Psiaki

Abstract:	Block algorithms have been developed to acquire very weak Global Positioning System (GPS) coarse/acquisition (C/A) signals in a software receiver. These algorithms are being developed in order to enable the use of weak GPS signals in applications such as geo-stationary orbit determination. The algorithms average signals over multiple GPS data bits after a squaring operation that removes the bits’ signs. Methods have been developed to ensure that the pre-squaring summation intervals do not contain data bit transitions. The algorithms make judicious use of Fast Fourier Transform (FFT) and inverse FFT (IFFT) techniques in order to speed up operations. Signals have been successfully acquired from 4 seconds worth of bit-grabbed data with signal-to-noise ratios (SNRs) as low as 21 dB Hz.
Published in:	Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001) September 11 - 14, 2001 Salt Palace Convention Center Salt Lake City, UT
Pages:	2838 - 2850
Cite this article:	Psiaki, Mark L., "Block Acquisition of Weak GPS Signals in a Software Receiver," Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001), Salt Lake City, UT, September 2001, pp. 2838-2850.
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