Track-Before-Detect (TBD) is an efficient method to detect dim targets for radars. Conventional TBD usually follows an approximate motion model of the target, which may cause an inaccurate integration of the target energy. A TBD technique on basis of pseudo-spectrum in mixed coordinates adopting an accurate motion model for bistatic radar system is developed in this paper. The predicted position in bistatic polar plane is derived according to a nonlinear function that exactly describes the constant Cartesian velocity motion. Then around the predicted position, a pseudo-spectrum is formulated and its samples are accumulated to the integration frame for energy integration. The evolution of the state and the procedure of accumulation of the target energy are derived elaborately. The superior performance of the proposed method is demonstrated by some simulations.

Traditional multiframe Track-Before-Detect (TBD) may incur adverse integration loss resulting from model mismatch in sensor coordinates. Its suboptimal integration strategy may cause target envelope degradation. To address these issues, a pseudo-spectrum-based multiframe TBD in mixed coordinates is proposed firstly. The data search for energy integration is conducted based on an accurate model in the x – y plane while target energy is integrated based on pseudo-spectrum in sensor coordinates. The algorithm performance is improved since the model mismatch is eliminated, and the pseudo-spectrum based integration facilitates well maintained target envelope. The detailed multiframe integration procedure and theoretical target integrated envelope are derived. Secondly, to cope with the unknown target velocity, a velocity filter bank based on pseudo-spectrum in mixed coordinates is proposed. The effect of velocity mismatch on algorithm performance is analyzed and an efficient method for filter bank design is presented. Thirdly, a parameter estimation method using characteristics of integrated envelope is presented for improved target polar position and Cartesian velocity estimation. Finally, numerical results are provided to demonstrate the effectiveness of the proposed method.