Radar Low-altitude Target Tracking Technology

When low elevation targets arc tracked using the monopulse radar, the multipath effects including the specular reflect and diffuse reflect degrade severely the tracking performance. In the radar elevation coordinate, the multipath effects are more severe, which cause periodic peak error in the target height measurement. In this paper two algorithms have been proposed to track the low-elevation targets in the presence of multipath: the interacting multiple model (IMM) algorithm and the non-Gaussian filtering algorithm.Two models are used in the interacting multiple model M) algorithm. In one model the measurement errors consist only of the "standard" measurement noise, while in the other the measurement errors are dominated by the multipath effects. The interacting multiple model (IMM) rithm automatically increases the variance of the altitude estimate and alleviates the iv.uiiipath effects, when the measurements are degraded. In the non-Gaussian filtering algorithm, the measurement errors incorporating the multipath effects are modeled as the non-Gaussian noise, and the filter are modified according to the score function. This algorithm, designed to track low-elevation targets, avoids the degrading of me performance because of ;..c non-Gaussian noise in the filter.