用水天线、星体和太阳测定六分仪指标差的
精度分析比较与实测经验
内容摘要
【摘要】航海六分仪是一种利用测量天体高度来求取船位的反射式光学仪器，是天文航海必不可少的仪器之一。根据其工作原理及结构，其具有测量精度高，操作方便，结构简单，完全独立，重量轻等诸多优点，曾经使得其得到了广泛的应用。但同时也它也有受天气的影响较大，不能在阴雨天使用等缺点。近年来，随着电子航海的迅速发展(如全球卫星定位系统， 雷达), 六分仪应用逐渐减少。而六分仪制造过程中会不可避免地引入机械误差，这也成了限制六分仪精度的一个重要因素。随着现代航海技术的发展，对船舶定位精度的要求也随之提高。本文阐述了六分仪指标差产生原因，通过利用水天线，星体以及太阳在不同天气条件下的实测工作，分析比较了六分仪在不同方法和天气条件下的指标差精度：利用太阳测六分仪指标差精度最高，星体次之，水天线最差。供航海人员参考。
关键词：航海六分仪；指标差；精度
Abstruct
Marine sextant is an reflected optical instrument which is essential for navigation, and we can get ship's position according to the celestial's height measured by it. Due to measuring principle and special structure, it have many merits, such as high accuracy, being easily operated, simple frame, completed independence, and light weight, all these advantages made it be used widely. But at the same time, being easily affected by weather and being invalid in the cloudy day are it's disadvantages. In the latest years, with the haste development of electronic navigation like GPS,RADAR etc. , the usage of marine sextant declines gradually. There certain to be added mechanical error during the manufacture process, this is another keynote fact affecting sextant's accuracy. With modern navigation technique's development, the demand of fixing accuracy increases. This paper analyses the accuracy of marine sextant index error by star, the visual horizon and the Sun. And gains the following conclusions: the highest accuracy being with the Sun, the moderate accuracy being with the stars, the lowest accuracy being with the visual horizon. This paper only gives the consult to navigator.
Key words: marine sextant; index error; accuracy
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目 录
1 航海六分仪的测角原理 …………………………………………………………… 4 2 六分仪的检查与校正 …………………………………………………………… 4 2.1 永久性误差 …………………………………………………………… 4
2.1.1 偏心差 ……………………………………………………………… 4 2.1.2 刻度差 ……………………………………………………………… 4 2.1.3棱性差 ……………………………………………………………… 4
2.2可矫正误差 ……………………………………………………………… 5 2.2.1 垂直差 … ………………………………………………………… 5 2.2.2边差 ……………………………………………………………… 5 2.2.3指标差 …………………………………………………………… 5 3 六分仪指标差的测定 …………………………………………………………… 6
3.1 航海六分仪的指标差 ……………………………………………………… 6 3.2 天气良好情况下的指标差测定 ………………………………………………… 6 3.2.1 利用水天线测定六分仪指标差 ………………………………………… 6 3.2.2 利用星体测定六分仪指标差 ………………………………………… 8 3.2.3 利用太阳测定六分仪指标差 ………………………………………… 9 3.3 天气状况一般时的六分仪指标差测定 ………………………………………… 12
3.3.1 用水天线测定六分仪指标差 ………………………………………… 12 3.3.2 用星体测定六分仪指标差 ………………………………………… 14
3.3.3 用太阳测定六分仪指标差 ………………………………………… 15
4 结束语 ……………………………………………………………………… 18
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用水天线、星体和太阳测定六分仪指标差的精度分析比较与实测经验
