In the rocket propulsion stage

only a few Doppler radars can track the target due to Doppler radar networks generally cover a very large area.We could not get the accurate trajectory estimate with insufficient velocity measurements.In this paper

we propose a trajectory estimation approach based on measurements fusion.The proposed method gets a rough trajectory estimate using Doppler radar angle-measurements.The initial trajectory estimate obtained by bearing measurement intersection is taken as the pseudo-measurement.Then

the pseudo-measurements are fused with velocity measurements via unscented Kalman filter (UKF).The Monte Carlo simulation results show that the proposed approach can compensate the accuracy of bearing-only measurement

and improve the track estimation.