A Novel Computationally Efficient Code Phase Acquisition Method

Chieh-Fu Chang, Wan-Hsin Hsieh, and Ming-Seng Kao

Abstract:	Fast Fourier transform (FFT) has been widely used as an efficiently computational tool in GNSS applications to search the code phase shift between the incoming sequence and the local reference sequence with complex multiplications of order N·log2N. In this paper, we propose a novel approach, called Phase Coherence Acquisition (PCA) method, which uses much less computation than FFT to search correlation peak of PN codes. The computation required for PCA is on the order of N complex additions and no multiplications, which is significantly less than FFT. The PCA method first partitions the code sequence into a number of subsequences and then maps each subsequence to a complex phasor. Next, a recursive algorithm is designed to efficiently extract the code phase information and approach the true code phase step by step.The computational superiority of PCA becomes outstanding when applied sequence length N is very large such that FFT approach becomes infeasible.
Published in:	Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011) September 20 - 23, 2011 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	2113 - 2119
Cite this article:	Chang, Chieh-Fu, Hsieh, Wan-Hsin, Kao, Ming-Seng, "A Novel Computationally Efficient Code Phase Acquisition Method," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 2113-2119.
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