A passive location method with one transmitter and one receiver using Direction Of Arrival (DOA) and Doppler measurements is proposed in this paper. The optimal trajectory analysis for the receiver is given for a moving target. The minimizing Geometrical Dilution Of Precision (GDOP) for target is used to analyze the optimal 2-D location. Unscented Kalman Filter (UKF) is used to estimate the position and velocity of the target by optimizing the receiver’s trajectory, and the optimal location can be obtained for every estimated moment. A computer simulation is used to illustrate the effectiveness of the proposed method.