Utilization of data wipe-off for improving tracking performance of GPS signal

• Main Authors: Chiu, Sheng-Feng, 邱聖逢
• Other Authors: Jwo, Dah-Jing
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/65114759297680551260

碩士 === 國立臺灣海洋大學 === 通訊與導航工程學系 === 103 === This thesis proposes that it is possible to attach data wipe-off to vector tracking loop of the global positioning system (GPS) for performance improvement in the weak signal environment. Conventional GPS receivers use scalar tracking loop and satellite signals from each channel are processed independently. On the vector tracking loop, signals in these channels can be shared with each other, therefore, the receiver can track signals successfully although the signal strength from individual satellite is so weak. However, the integration interval of the correlator is extended over 20 ms in low C/No levels. Consequently, navigation data wipe-off is needed to avoid energy loss due to bit transitions. To solve this problem, a data wipe off algorithm is presented on the basis of pre-detection method to detect data bit sign reversal every 20 ms and wipe off. This paper uses the data wipe-off method calls energy-based bit estimation algorithm. The simulation results show that the vector tracking loop with wipe-off keep tracking accurately in weak signal.