空对地雷达精确定位的电波折射误差修正方法

Radio-wave refraction error correction method in precision locating of air-to-ground radar

要利用空中飞行器上武器来攻击地面目标,首先必须对地面目标进行精确定位,然后才能实施精确打击。大气介质的不均匀性使得雷达测量定位产生折射误差,从而影响雷达的定位精度。因此对高精度的雷达系统,必须进行电波折射误差修正。这里采用空中雷达处的大气折射率来预测空中雷达电波传播的大气剖面,再经过电波射线描迹方法推出了一种实用于空中雷达对地面目标精确定位的电波折射误差修正方法。仿真计算表明:俯视雷达与同一传播路径上地基雷达的计算结果很吻合。随着俯视角度的增大,电波折射引起的误差逐渐减小,反之,俯视角度愈小,电波折射误差愈大。当雷达在10 km高度时,5°以下俯角的电波折射误差达10 m以上。

For attacking the ground target precisely with weapons on aircraft, the location of the target must be confirmed accurately at first. Nonuniformity of atmosphere medium may cause refraction error in radar instrumentation missions and thus influence the radar＇s locating precision. Therefore, the radio-wave refraction error must be corrected in highly precise radar system. The atmospheric refractive index around the radar is used for predicting the atmospheric section of radio-wave propagation. Then by using ray tracing method, the radio-wave refraction error correcting method was deduced for locating the target on the ground precisely. The simulation revealed that the result of down-looking radar was compatible with that of ground-based radar in the same transmission path. The error caused by the radio-wave refraction decreases with the increase of downlooking angle and increases with the decrease of the angle. When the radar is at the height of 10 km, the radio-wave refraction error reaches more than 10 m with down-looking angle below 5°.