To solve the problem of low positioning accuracy issue due to trajectory effect of the observer,instable surveillance data receive rate and weak observability during slow moving target tracking by the single-airborne ESM,a course optimizing filtering model under non-equal interval data scenarios based on shifted Rayleigh filter was proposed in this paper,which updated the sampling interval changes in real-time to resolve the problem of instable bearing samplings.It also estimated the optimal movement direction of the observation platform based on the minimum trace of the location covariance matrix,which avoided divergence owing to improper relative position and enhanced positioning accuracy.The simulation results indicate that,in addition to the maintained good tracking stability,the proposed algorithm has fast convergence characteristics,which effectively reduces the positioning error.