一种基于全站仪平面法线的自动天文定向系统
2021-01-11冯冰砚
冯冰砚
[摘 要]目前定向都是直线定向,针对平面定向,提出使用全站仪测量平面均匀分布点,通过最小二乘法原理拟合平面求得平面法线在全站仪坐标系的水平方位角,利用天文定向原理计算得到平面法线与真北夹角,同时为了消除人仪差和提高天文测量效率,使用全站仪集成的相机拍摄天体进行自动天文定向。系统通过在天文边测试,结果表明:利用全站仪集成的CMOS相机拍摄天体,对图像滤波和自动阈值计算生成二值化图像再开操作等相关图像处理方法,得到星体质心精确像素坐标,系统整体精度能够达到四等天文要求。可见,此基于全站仪平面法线自动天文定向系统能够提供较高的定向精度,可以为其他定向手段提供真北基准。
[关键词]平面定向;天文定向;真北;基准
[中图分类号]TP391.41 [文献标志码]A [文章编号]2095–6487(2021)10–00–02
An automatic Astronomical Orientation System Based on Total Station Plane Normal
Feng Bing-yan
[Abstract]At present, the orientation is a straight line direction, according to the orientation of the plane, proposed to use the plane uniform distribution point, through the least square method to fit the plane in the plane azimuth of the coordinate system, calculate the plane normal and the true north angle, in order to eliminate the humanin strument difference and improve the astrometry efficiency, using the camera integrated with the station for automatic astronomical orientation.The system is tested on the astronomical side that the integrated CMOS camera can generate the image filtering and automatic threshold calculation Off the image processing method, it obtains the precise pixel coordinates of the star center of mass, and the overall accuracy of the system can meet the four-class astronomical requirements.It can be seen that this automatic astronomical orientation system can provide high directional accuracy, and can provide a true north reference for other orientation Benchmark.
[Keywords]plane orientation; astronomical orientation; true north; Benchmark
传统天文定向装置的工作原理是:①测定地面直線的正北方位角;②通过经纬仪或全站仪测定目标点的水平方位角和太阳的水平方位角并记录时间,根据定位三角形,由球面三角公式计算出此时太阳与真北的夹角;③根据目标点和太阳的水平方位角差值,得出地面直线和真北夹角,完成地面直线定向的功能。
传统天文定向系统是通过人眼观测星体,全程人工测量。为了消除人仪误差,需要到天文边标定。目前现有的基于图像处理的天文定向技术在使用相机拍摄太阳目标时,需要通过人眼判断太阳是否处在相机的视场范围内或通过观测其他星体基于全站仪水平方位角概略定向,这些系统都不能离开人员的操作和主观的判断,不能算真正意义上的自动天文定向系统。……
