A Track-Before-Detect Method for Rotating Radars with Revisit Interval Uncertainty

In traditional track-before-detect (TBD) algorithms, intervals between frames are considered to be uniform. The uncertainty of revisit intervals is not taken into account. However, revisit intervals of the target varies with its states in rotating radars. This may lead to degradation in energy integration due to the use of inaccurate revisit intervals in conventional methods. In this paper, a velocity-filtering-based TBD method with revisit interval uncertainty (RIU-VF-TBD) is proposed to address the above problem. The revisit interval is solved precisely using the space-Time joint solution. Using the angle relation between target movement and the motion of antenna, the revisit interval is solved iteratively until accuracy requirement is reached. Each measurement cell in polar coordinates is converted to Cartesian coordinates and predicted according to an assumed velocity and the precisely solved revisit interval. Then, every predicted Cartesian position is converted back to polar coordinates for energy accumulation. Procedures of the revisit interval calculation and energy integration are derived in detail. Simulation results demonstrate the superiority of the proposed algorithm compared with conventional VF-TBD methods.