A 2-D Parallel Differential Matched Filter (PDMF) used as Correlator of GPS Acquisition for Low-Complexity Design

Chia-Wei Chen, Sih-Huan Chen, Wei-Lung Mao, Hen-Wai Tsao

Abstract:	Finding the code phase and Doppler frequency of visible satellites is the purpose of code acquisition in the GPS positioning; however, this process usually has huge operation count, high hardware cost for correlator and large usage of memory consumption. In order to reduce the huge operation count and minimize the usage of memory consumption, we propose a two-dimensional parallel differential matched filter (2-D PDMF) as the correlator for code acquisition. Our proposed 2-D PDMF combines the concepts of PDMF [1] and 2-D correlator[2]. In the referred PDMF [1], one section of incoming GPS signal must do parallel correlation with GPS coarse/acquisition (C/A) code of multiple satellites. In the PDMF, the operation number reduces but memory consumption for coherent and incoherent integration rises because the correlation results of multiple satellites must be stored. Moreover, it is not flexible while Doppler frequency is compensated since each satellite signal has its own Doppler frequency. In our proposed design, firstly, a 2-D correlator is adopted to break C/A code of one satellite into multiple sections of shorter code segments. Then we can use PDMF to do correlation between GPS signal and these multiple sections of shorter code segments. In our proposed 2-D PDMF, the memory consumption for coherent integration and incoherent integration is less than that in PDMF because the correlation results of only one satellite needs to be stored. Furthermore, the proposed 2-D PDMF has larger flexibility while Doppler frequency is compensated since only one satellite is concerned each time. In the 2-D correlator, the equality among multiple sections of shorter spreading code has to be checked by complex control unit to reduce the operation count of code acquisition. But in our proposed 2-D PDMF, the operation count of code acquisition reduces and does not need to check the equality among multiple sections of shorter spreading code, so the control circuit could be simplified.
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:	1040 - 1045
Cite this article:	Chen, Chia-Wei, Chen, Sih-Huan, Mao, Wei-Lung, Tsao, Hen-Wai, "A 2-D Parallel Differential Matched Filter (PDMF) used as Correlator of GPS Acquisition for Low-Complexity Design," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 1040-1045.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In