以基礎誤差傳播探討多星系定位

The Uncertainty Improvement of Multi-Constellation Positioning as Evaluated with Basic Error Propagation

全球導航衛星定位已有多個運作中的系統，多星系的聯合定位不僅可以藉由可視衛星數目的增加，有效提升定位成功率，亦有降低定位不確定度的效能。在民國110學年度科技校院四年制與專科學校二年制統一入學測驗，土木與建築群專業科目（二）試題中，有一題以雙星系觀測，探討降低定位不確定度的選擇題。雖然該題在計算面十分簡單，但是在觀念上實有警醒之處，堪稱本試卷之亮點。本文由此一試題著手，嘗試探討有關測量觀測量的基本相關觀念議題，敘明增加異源觀測量時，如果只有隨機誤差，且能掌握各觀測量的不確定度，則必然可以降低所求估值之不確定度。

"Global Navigation Satellite Systems (GNSSs) has multiple systems in operation. Consequently, integrated multi-constellation positioning becomes feasible. This integrated positioning scheme could not only increase the success rate with increased visible satellite number, but also could reduce the uncertainty of the position estimated. In the 2021 united exams for professional education programs, there is one question related to this subject in the category of Professional Subject (2) of the Civil Engineering and Architecture group. Despite the simplicity of this question, a fundamental concept is queried, which may be one of the highlights in this exam. This article discusses this question, and explores the fundamental concept about redundant observations. That is, while random error is the only error source, and the uncertainties of the observation are known, the more redundant the observation, the better the estimate."