A High Dynamic Weak Spread Spectrum Signal Acquisition Strategy Based on Iterative Local Search

To solve the acquisition problem of the satellite-ground microwave link ranging of the China Space Station, iterative local search (ILS) is proposed. In this paper, an iterative-local-search-based acquisition strategy is presented, and a Doppler frequency and code phase transfer model is designed, which can accomplish acquisition by multiple rounds of two-dimensional search. The adaptability of the ILS improved traditional acquisition algorithm to a high dynamic and low signal-to-noise ratio (SNR) environment can be significantly improved without relying on prior information. For the classical parallel code phase acquisition algorithm, the performance of the ILS acquisition strategy was experimentally evaluated for high dynamic weak signals, and the results demonstrated the superiority of the proposed strategy. The computational complexity of the ILS improved parallel code phase acquisition algorithm was greatly reduced. The sensitivity of the parallel code phase acquisition algorithm improved by the ILS strategy to the acquisition of weak signals in a dynamic environment was significantly improved.