卫星导航的不确定性、不确定度与精度若干注记

卫星导航定位必然有误差。其误差可分为偶然误差、系统误差、异常误差、有色噪声等。误差存在多种不同的度量模型和度量方法，如，精密度（precision）、精确度（accuracy）、可靠性（reliability）、不确定度（uncertainty）等。实践中，经常有学者和工程技术人员将精度指标描述成误差，也有人将不确定性与不确定度概念相混淆。尤其是在描述精度指标或误差指标时，经常将精度指标描述成误差，将误差指标描述成精度，如在卫星导航定位中，用户距离误差经常被描述成用户距离精度。本文基于不确定度概念将卫星导航中的用户距离误差重新作了定义；给出了用户距离误差与用户距离精度的关系；并提出将不确定性与不确定度进行区别；对测量平差中常用的可靠性概念进行了描述；最后给出了几点注记。

Some Notes on Uncertainty, Uncertainty Measure and Accuracy in Satellite Navigation

Uncertainty always exists in satellite navigation process and results, which includes random errors, systematic errors, outliers and colored noises etc. There are many different measures for evaluating the quality of the navigation results, such as precision, accuracy, reliability and uncertainty, and so on. In practice, the accuracy, precision and error itself are often confused by the users, so are the uncertainty and the uncertainty measures. Especially, the accuracy is often followed several times standard deviation or error percentage. For example, the user range accuracy (URA) index is often followed standard deviation. In this paper, the user range error (URE) is redefined based on the uncertainty concept. Then the URE and URA are distinguished and their relationship is obtained. The uncertainty is distinguished from the uncertainty measure. The often used reliability concept in geodetic adjustment is introduced and described. At last, several notes on the concept of error, precision, accuracy, URE and URA are given.