Optimum Gain in the Process of the GPS Signal Acquisition

Qin Zhengdi

Abstract:	In the GPS signal acquisition process for the C/A code, the signal coherent length is a big concern for the signal integration. The signal coherent length is mainly limited by the 50 Hz navigation data on top of the CDMA signal. In a blind situation, the receiver is not synchronized with the navigation data and the data information is unknown. It gives an extra error to the system due to the boundary crossing between different data bits. The longer the co- herent integration time, the bigger the error that occurs. On the other hand, the acquisition decision process is per- formed in a 2-dimentional (time delay-frequency) plane. The frequency resolution or the size of the 2D plane is proportional to the signal coherent integration time. The size of the 2D plane also affects the acquisition probabil- ity of the receiver. For a given acquisition time, the optimization process for selecting the coherent integration and the non-coherent integration time gives the best system performance. The acquisition probability is directly related to the system gain over the noise. In this report, the noise behavior is analyzed for all the process steps of the acquisition. The system gain over the Gaussian noise is analyzed for dif- ferent configurations using different coherent and non- coherent integration lengths.
Published in:	Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000) September 19 - 22, 2000 Salt Palace Convention Center Salt Lake City, UT
Pages:	891 - 894
Cite this article:	Zhengdi, Qin, "Optimum Gain in the Process of the GPS Signal Acquisition," Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000), Salt Lake City, UT, September 2000, pp. 891-894.
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