Code Acquisition Using Subexpression Elimination

Y-T. Lee, H-W. Tsao, F-R. Changg, H-C. Yeh, K-T. Chen

Abstract:	As code acquisition in the baseband digital signal processing is still one of the major computational bottleneck limiting the time to first fix (TTFF) in navigation devices, this paper proposed a new code acquisition method that results in a lower computational complexity architecture and is more appropriate for searching multiple satellites. We transformed the traditional code acquisition problem into a multiple constant multiplications problem such that the technique of subexpression elimination can be utilized to reduce the addition complexity within code acquisition. A fast acquisition engine based on the proposed method is also demonstrated for its usability for GPS coarse/acquisition (C/A) codes. According to the simulation results, the number of required additions given the number of simultaneously processing satellites is larger than six can be decreased by about 70%, compared to the traditional architecture.
Published in:	Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009) September 22 - 25, 2009 Savannah International Convention Center Savannah, GA
Pages:	3252 - 3259
Cite this article:	Lee, Y-T., Tsao, H-W., Changg, F-R., Yeh, H-C., Chen, K-T., "Code Acquisition Using Subexpression Elimination," Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009), Savannah, GA, September 2009, pp. 3252-3259.
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