A digital DS/BPSK code acquisition circuit is proposed
and the mathematics model is derived when the receiver operates in high dynamic situation.The effect of Doppler frequency shift and PN phase error on the acquisition performance is analyzed.A scheme used to improve the probability of detection
and decrease the probability of false alarm is introduced.According to the analysis
the improved digital code acquisition circuit has higher probability of detection and lower probability of false alarm
and can be adopted for shortening the acquisition time effectively.