應用零基線原理檢驗接收儀內部雜訊之研究

Abstract

在GPS衛星測量接收儀定位精度檢驗中，零基線測試是相當重要的一環，且是用以檢定接收儀內部雜訊的主要方法之一。其原理為應用分流器使兩台接收儀接收來自同一天線之衛星訊號，經分流器所接收的訊號具有相同的環境條件，因此所有的誤差將於差分過程中相消，然而因為各接收儀中參數微小的不同、通道時間延遲或接收儀老化、故障…等原因，而使得基線長不為零，故用此原理來檢驗儀器的標準精度。 在本研究中，依照TEQC所檢測的品質成果而言，建議檢測時間應取4小時以上，取樣間隔設定為5秒者最佳，而以Bernese 4.2 版軟體所解算基線成果驗證，發現可達到基線長1mm以內的極優成果。而就學術用研究軟體Bernese 4.2版軟體與GPSurvey 2.35版商用軟體之比較結果來看，Bernese 4.2版學術用研究軟體呈現了與資料品質檢測相同的成果，由此可知Bernese 4.2版學術用研究軟體的解算精度較高。而針對一般使用者檢驗接收儀的做法，使用商用軟體解算，接收時間30分鐘的成果已可接受。

In GPS satellite receivers position accuracy examination, the zero baseline test is a very important step. Also, zero baseline test is one of the main method of receiving the internal noise in instruments. This test is to receive the satellite signal from the same environmental conditions. For this purpose, many different trademarks' receivers are connected with a GPS antenna splitter, therefore, all the satellite signal is received from the same antenna. However, the baseline length is not zero because each receive’s parameters in instrument are different, Such as channel time delays or receives the instrument age…Etc. Therefore, it is usually to test standard accuracy of the instrument with this principle. In this research, the results’ quality is checked with TEQC. The suggestion test time is more than 4 houses, and the sampling time interval is 5 second. The test precision of a baseline is within 1mm using Bernese 4.2 version software to calculate. Comparison with GPSurvey 2.35 version software, Bernese 4.2 version is more stable and more accurate. In general, 30 minutes are the enough time to receive data using GPSurvey 2.35 version software to execute the data processing.