Abstract: In order to realize fast acquisition for navigation signals of navigational trajectory correction projectiles in high dynamic environment and to get rid of global position system(GPS) restriction, a complete fast acquisition scheme of missile-born receiver assisted by trajectory is proposed based on pseudolite regional positioning system. First, expectation trajectory is used to get initial value of Doppler shift in the beginning of acquisition. Thus, Doppler shift searching range is reduced. Meanwhile, the improved Doppler shift searching strategy is used to reduce searching time. Furthermore, cubic-spline interpolation method is proposed to process correlation peak and neighboring value to improve the measurement precision of coarse/acquisition(C/A) code phase at low sampling rate. Algorithm analysis and simulation results show that the scheme can effectively shorten Doppler searching time and improve the measurement accuracy of PN code phase.