Abstract: In satellite navigation and positioning system, time is important information for fast and direct acquisition of long cycle code, one of its important aspects is the uncertainty compression of signal＇s propagation delay to reduce time search range. Based on coarse data of positions of user and satellite, estimation algorithms of propagation delay between different satellites and users are given. Simulation results indicate that the algorithm can reduce the delay＇s uncertainty range greatly, even with great position errors the uncertainty range still can be reduced to the half, and is effective for the fast acquisition of long cycle code.