偏馈法距离校零误差校正

针对偏馈法距离校零产生的误差，提出一种几何校正方法。与传统的零值分离方法不同，该方法基于距离测量原理，用几何法分解对塔校零和偏馈校零的信号路径，并计算对塔校零的距离零值，然后采用参数传递的方式代入到偏馈校零的表达式中导出数学模型，使两种校零方法的距离零值完全等效，从机理上消除了偏馈法的零值误差。同时，考虑近场时延误差和漏射误差，可确定校零天线的最佳安装位置。试验结果表明，校正后的偏馈校零与对塔校零相比，距离零值的误差小于1 m。由于计算模型简单易用，该几何校正方法对当前无塔标校的应用具有一定参考价值。

Error correction of zero range calibration by feed set-off

For errors generated in zero range calibration by feed set-off,a geometric calibration method is proposed,which is different from conventional zero value isolation method and based on range measurement concept. The signal paths for zero range calibrations by feed set-off and calibration tower are separated by geometric method,and zero range set constant for calibration tower is calculated and substituted into expression for feed set-off calibration in parameter transferring way to derive a mathematic model,which makes zero range set constants obtained in two ways completely equivalent in order to eliminates zero range error in feed set-off calibration in mechanism.By considering near field time delay error and leak emitting error,optimal installation location of zero range calibration antenna can be determined. The test results show that the zero range error corrected by feed set-off calibration is less than 1 m compared with that by calibration tower correction. Because the calculation model is simple and convenient,this geometric calibration method is valuable to towerless calibration applications.