摘要
大气垂直折光角及其起伏是影响垂直角观测精度的重要因素,由于它们都与时间密切相关,垂直角观测质量的好坏也必然与作业的时间有关.以大气垂直折光角及其起伏的日变化规律为基础,分析了折光角及其起伏在不同时间对垂直角观测值的不同影响,讨论了高精度垂直角的最佳观测时间问题:对于同时对向观测和单向观测,晴天日出、日落前后相对最佳,中午前后最差,其它时间较佳;非同时的对向观测,除极不对称的地形之外,中午前后相对最佳,日出、日落前后最差,其它时间较佳.视线较低、距离较长且精度要求特别高的垂直角观测,应该选择阴天作业.
Atmospheric vertical refraction angle and its undulation are important factors deciding the precision of the vertical angle observation. Because they are closely related to time, the quality of the vertical angle observation is decisive to work time. Based on the daytime variation laws of the atmospheric vertical refraction angle and its undulation, the influences exerted by refraction angle and its undulation on the observed value of the vertical angle in different times are analyzed. The problems of the optimum time for precise vertical angle observation are discussed. For simultaneous direct and reversed observations and the unilateral observation, sunrise or sundown in sunny day is the best observation time, while noontime the worst. For non-simuhaneous direct and reversed observations, except extraordinary dissymmetric topography, noontime is the best observation time, sunrise or sundown the worst. For lower line of sight, longer distance, and especially high precision, the vertical angle observation can be done in overcast sky.
出处
《桂林工学院学报》
北大核心
2007年第2期212-215,共4页
Journal of Guilin University of Technology
基金
广东省自然科学基金资助项目(5001833)
关键词
垂直角观测
最佳时间
大气折光角
起伏
vertical angle observation
optimum time
atmospheric refraction angle
undulation
