GNSS天线连接器同轴度误差测量技术

为测量GNSS天线连接器同轴度误差,构建了连接器分段旋转数学模型,提出了一种水平转台和机器视觉结合的非接触式测量方法,搭建测量装置并进行了测量实验.分析连接器运动方式和同轴度误差测量方法,确定各轴线之间的偏移关系,建立同轴度误差数学模型和测量模型.搭建测量装置,相机安装在水平转台上方,光轴平行于水平转台轴线.旋转水平转台,使用相机捕捉转接螺杆端面圆心位置并拟合轨迹,完成测量装置同轴度误差自标定.将连接器安置在水平转台上,旋转水平转台,测量连接器顶部螺纹杆轴线相对水平转台轴线的偏移.旋转连接器的承载器,测量连接器顶部螺纹杆轴线相对承载器轴线的偏移.最终,综合各轴线的偏移关系得到连接器同轴度误差的最大值.实验结果表明,测量装置对GNSS天线连接器同轴度误差的测量标准差为9μm,单次测量结果的扩展不确定度U=30μm(k=2),满足GNSS天线连接器0.1 mm至1 mm量级的同轴度误差的测量需求,使用连接器同轴度误差修正GNSS超短基线测量结果,可以显著提升基线测量精度.

Coaxiality Error Measurement Technology for GNSS Antenna Connector

In order to measure the coaxiality error of GNSS antenna connector,a mathematical model of segment rotation of connector is constructed,and a non-contact measurement method combining horizontal turntable and machine vision is proposed.Then the measuring device is built and the measuring experiment is carried out.Based on the analysis of the motion mode of the connector and the measurement method of coaxiality error,the deviation relationship between the axes is determined,and the mathematical model and measurement model of coaxiality error are established.In the measuring device,the camera is mounted above the horizontal turntable with the optical axis parallel to the horizontal turntable axis.Rotate the horizontal turntable,use the camera to capture the center position of the end face of the transfer screw and fit the orbit,and complete the self calibration of the coaxiality error of the measuring device.Place the connector on the horizontal turntable,rotate the horizontal turntable,and measure the deviation of the thread axis at the top of the connector from the axis of the horizontal turntable.Rotate the carrier of the connector,and measure the deviation of the thread axis at the top of the connector from the axis of the carrier.Finally,the maximum coaxiality error of the connector is obtained by synthesizing the deviation relations of the axes.The standard deviation of measurement device for coaxiality error of GNSS antenna connector is 9μm,and the expanded uncertainty of single measurement result is U=30μm(k=2),which meets the measurement demand of coaxiality error of GNSS antenna connector in the level of 0.1mm to 1mm.Using connector coaxiality error to correct GNSS ultra short baseline measurement results can significantly improve the baseline measurement accuracy.