Radome effect on the radar homing system

雷达末制导系统中的天线罩，如果不适当地控制其厚度，会使脱靶量增大甚至系统不稳定。本报告根据迄今为止在杂波效应分析等方面所采用的系统框图，采用非线性协方差分析方法分析了这些影响。1995财政年度，导弹被作为三阶滞后系统处理。首先在框图中引入天线罩效应，分析了系统的稳定性，然后介绍了系统的状态方程和协方差方程。分别对天线罩误差斜率在飞行过程中为常数和随时间变化的情况进行了仿真。文中给出了不同参数变化时天线罩误差斜率与脱靶量的关系，阐明了天线罩误差斜率阶跃变化和正弦变化的影响。稳定性分析表明，五阶模型不仅在天线罩误差斜率为负值时，而且在天线罩误差斜率为正值时也会引起不稳定。状态方程和协方差方程以及程序都适用于5阶模型。与第三阶模型相同的标称值给出了严重的结果：大约两倍的脱靶距离，以及上述的不稳定性。在三阶模型的基础上进行了参数研究，最全面地分析了天线罩的影响，特别是对时变的影响。

The radome in radar homing system makes the miss distance increase or even the system unstable unless its thickness is properly controlled. This report analyzes these effects by using a nonlinear covariance analysis method, based on the system block diagram the authors hitherto adopted in the clutter effect analysis etc.In FY 1995, the missile was handled as a third order lag system. First, the author introduced the radome effect into the block diagram, analyzed the system stability, then introduced the state and covariance equations. Simulations were performed for the case of the radome error slope being constant during the flight, and for the case of time-changing. The relations of radome error slope vs. miss distance are shown for various parameter changes in the former, the effect of stepped and sinusoidal changes of the radome error slope are clarifed in the latter.In FY 1996, the missile was handled as a 5th order lag system. The stability analysis indicated that the 5th order model introduces instability not only for minus values of the radome error slope but also for plus values. The state and covariance equations, and hence the programs were accommodated to the 5th order model. The same nominal values as the 3rd ordor model gave severe results : approximately twice of the miss distance, and the instability described above. Parameter studies were performed as done in the 3rd order model.The effect of a radome, especially that of time changing, which was known only fragmentary was ahnost fully analyzed through this investigation.