Adaptive Phase Correction Loop for Enhanced Acquisition Sensitivity

Andreas Schmid, Christoph Gunther and Andre Neubauer

Abstract:	Location based services and the E-911 mandate require enhanced reception sensitivity. The satellite navigation receivers inside mobile telephones can use acquisition assistance data. The main task of the receiver is hence, to acquire the satellite signals with the largest reception sensitivity possible. Only very high sensitivities can overcome the signal attenuation caused by moderate indoor and deep urban environments. Since the maximal coherent integration period is limited by various factors, current enhanced sensitivity single-shot positioning receivers employ noncoherent integration of the coherently integrated predetection samples. However, this method introduces a squaring loss. This paper introduces a novel acquisition method that provides even for large variations of the frequency deviation and frequency drifts a gain of around 1.2dB over noncoherent integration. Each coherently integrated predetection sample is multiplied with the complex-conjugate of the previous predetection sample. These products are accumulated to raise the signal-to-noise ratio. The resulting signal phase after the second integration is fairly stable and can be estimated. The samples are therefore rotated by the estimated signal phase before they are further accumulated.
Published in:	Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005) September 13 - 16, 2005 Long Beach Convention Center Long Beach, CA
Pages:	168 - 177
Cite this article:	Schmid, Andreas, Gunther, Christoph, Neubauer, Andre, "Adaptive Phase Correction Loop for Enhanced Acquisition Sensitivity," Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005), Long Beach, CA, September 2005, pp. 168-177.
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