Research On High Dynamic Weak GPS Signal Acquisition Algorithm

GPS acquisition algorithm is an important part of GPS receivers, the acquisition of weak signal under high dynamic condition is researched in this paper. Generally speaking, acquisition must be fast enough under high dynamic condition, and enough integration time should be need when the GPS signal is weak, we can see that these two condition are contradiction.According to the character of acquisition, fast acquisition based on FFT/IFFT is adopted in this paper, and differential correlation(DC) is used to incrase integration time. Based on this frame, acquisition strategy is researched, as classical TONG acquisition strategy and NM strategy can not apply to the high dynamic and weak signal condition, a new strategy named Double Threshold(DT) strategy is proposed, which can performance better under high dynamic, weak signal condition. Some other work has been done in this paper, such as the data pretreatment of FFT, mutiplexing and so on.The designed acquisition algorithm has been realized on FPGA, then performance is tested on the prototype, the result indicates that, when the velocity achives8000m/s, acceleration achives50g, if we set the false alarm probability1×10-7,then the detect probabilty can achieve0.98when the signal is as weak as-138dBm.In this paper, some work has been done for high dynamic weak GPS signal acquisition, and they are meaningful for the subsequent work.