面天线检测数据处理方法的探讨

On the Data Processing Methods of Surface Antenna's Calibration

对面天线检测数据处理方法作了一些有益的探讨。从获取被测物的三维坐标后到获取真正有用的信息这一过程需要经过坐标转换和表面误差计算两个步骤 ,其中坐标转换是关键。在坐标转换方面 ,文中提出了曲面自由拟合、公共点转换和CAD面型转换三种方法 ,阐述了这些方法的数学模型 ,并且用实测数据进行了验证计算。理论分析和实际计算两方面显示 :CAD面型转换法既不需要天线的曲面方程 ,也不需要有已知的公共点 ,结果准确、可靠 ,是一种理想的方法 ;如果没有天线的CAD面型 ,但却存在公共点时 ,公共点转换法也是较理想的方法 ,其结果与给定的公共点误差有关 ;如果既没有天线的CAD面型又无公共点或公共点误差很大时 ,只能采用曲面自由拟合法 ,该法准确度最高 。

The data processing methods of surface antenna's calibration are deeply discussed in this paper. There are two steps from 3D measuring coordinates to useful information (for example, surface accuracy): coordinate transformation and surface accuracy calculation. The first step is more important. Three methods (surface free transformation, common point coordinate transformation and CAD surface transformation) are discussed in this paper. The mathematic models and formulas of these methods are deduced and some results are given finally. According to the theoretical analysis and actual calculation we can see that the CAD surface model fitting is the best method because it needs neither the surface equation nor common point but the CAD surface and its result is reliable. If there is no CAD surface model but a number of common points, then the common point coordinate transformation is a better method, but its result would be influenced by the accuracy of common points. If there exists neither CAD surface model nor common point or the accuraey of common points is low, the surface free fitting is also a good method, which has a high surface precision but the calculated surface might be shifted.