A Novel Method To Extend Coherent Integration for Weak GPS Signal Acquisition

In order to enhance the sensitivity of Global Positioning System receivers, increasing the coherent integration time in the acquisition process is necessary. This letter analyzes the limitation to coherent integration in acquisition algorithms due to the bit sign transition of navigation data and proposes a novel time parallel acquisition algorithm with transition detection (denoted as TPATD) to overcome the bit sign transition limitation. Fast Fourier transform operation is applied to the proposed TPATD algorithm to search the code delay in parallel. Meanwhile, the algorithm extends the coherent integration time to one entire navigation data bit duration. Simulation results demonstrate the effectiveness of the proposed algorithm. The receiver operating characteristic curves show that the TPATD algorithm outperforms the existing acquisition techniques.