Data Compression for Assisted-GPS Signal Processing

Jinghui Wu and Andrew G. Dempster

Abstract:	A concept of assisted-GPS based Snapshot receiver has been proposed by Andrew Corporation.. In this novel A-GPS system, demands on the complexity of design as well as the computation load and resources in a client receiver can be eased, especially when it is processing for multiple navigation systems. The functionality of the client receiver is simplified by recording and transferring the sampled intermediate frequency (IF) data directly to the server in the network. Instead of providing a position solution within the client receiver, the acquisition search engine as well as the position solution calculation is performed in the network server. However, in this way the burden of data transfer between the client and server receiver via the network becomes one of the major concerns. Therefore, investigations into data compression techniques in the client receiver can lead to important gains. In this paper, we show the relation between system sensitivity of a GPS signal and the amount of captured IF data in a given “snap-shot” or time frame. The goal of the project is to determine the feasibility and optimal values for the system parameters in terms of minimizing the data size while preserving reasonable detection sensitivity and accuracy. This paper presents the SNR loss and detection accuracy for a single GPS signal in the presence of additive Gaussian noise by considering the combination effects of narrow bandlimiting, low sampling frequency and 1-4bits quantizers. Empirical analysis is extending the recent findings on this combinations loss with sampling rates under Nyquist rate for GPS BPSK signal.
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:	1019 - 1027
Cite this article:	Wu, Jinghui, Dempster, Andrew G., "Data Compression for Assisted-GPS Signal Processing," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 1019-1027.
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