赋形旋转抛物面天线母线自适应分段拟合

赋形旋转抛物面天线母线拟合常用的方法包括多项式整体拟合和等间隔分段拟合,多项式整体拟合结果阶次高、计算量大,且高阶多项式在边缘处拟合的结果容易振荡;而等间隔分段拟合则是对母线数据按等间隔分段,分段方式具有一定的盲目性,容易造成拟合参数多、光滑性差等问题.针对上述问题,提出了一种基于母线拟合残差分布的自适应分段拟合方法,该方法包括初始整体拟合和分段拟合两步,初始整体拟合用以确定各离散点的拟合残差分布,分段拟合先参照残差分布情况对离散点数据分段,然后采用低阶多项式对各段数据进行拟合.经过实例拟合对比,该方法可避免高阶拟合的不稳定性,减少了分段数,更适用于赋形旋转抛物面天线母线的拟合.

Adaptive Piecewise Fitting of Shaped Rotational Paraboloid Antennas Generatrix

Common generatrix fitting methods of the shaped rotational paraboloid antenna include polynomial overall fitting and equal-interval piecewise fitting. The order of polynomial overall fitting is high so that the calculation load is large, and the fitting result on the edge is easy to oscillate. In the second method, generatrix data is segmented into several equal intervals, but the segment method is unreasonable, which is easy to cause the result of more fitting parameters and poorer fitting smoothness. In order to solve the above problems, an adaptive piecewise fitting method based on the fitting residual distribution is proposed. The method consists of two steps: initial overall fitting and piecewise fitting. In the initial overall fitting, the fitting residual error distribution of each discrete point is calculated. In piecewise fitting, firstly, the discrete point data are segmented according to the residual error distribution. Secondly, the data of each section are fitted by low-order polynomial. The comparison of fitting example shows that the method proposed in this paper can avoid the instability of high-order fitting, reduce the number of segments, and be more suitable for the generatrix fitting of shaped rotational paraboloid antenna.