左: 單次平均測定座標法的畫面, 呈現精確度(Confidence, 這是統計用語)
右: 多次分時測定座標法的記數器(Sample)
支援機種:
Oregon 550T: 無法得知何時起支援.
Oregon 400T: 英文韌體3.10起
Colorado 400T: 英文韌體 3.00起
文章中提到過去我想知道的重點:
The first implementation offering the multi-sample technique is offered as a new application on our Oregon® platform.
Oregon機種是多次分時測定座標法功能的第一種機型.
Traditional Short-term averaging involves averaging a location over a few minutes. This technique removes large temporary errors in GPS position and is most beneficial when conditions are challenging (such as dense tree cover) but can not mitigate errors from the current satellite constellation. For best results in difficult conditions, our research found short-term averaging should be done for at least 5 minutes, preferably 7 to 10 minutes. Oregon’s application indicates how long it recommends averaging based on current conditions.
傳統的單次平均測定座標法(eTrex Vista HCx就支援此功能), Garmin提到在同一地點進行連續5分鐘的座標測定, 若是延長到7到10分鐘會更好, 而Oregon等新機種則會依照目前衛星狀態提出建議測量的時間.
For multi-sample averaging, our research uncovered two important factors in achieving the greatest error reduction: the number of samples collected and the elapsed time between samples. For optimal results, at least 4-8 samples should be collected spaced at least 90 minutes apart (allowing the satellite constellation sufficient time to change).
接下來談到進階的多次分時測定座標法, 文中提到兩個重要因素可以降低測定座標誤差, 一為測量次數, 二為兩次測量時間的間隔時間. 因此Garmin建議為求最佳測量效果, 最好進行4到8次測量, 每次測量之間間隔90分鐘, 讓衛星幾何分佈有所不同.
