| Summary: | 碩士 === 國立臺灣海洋大學 === 通訊與導航工程學系 === 101 === In this thesis, the autonomous integrity monitoring and the detection and exclusion (FDE) mechanisms will be incorporated into the vector tracking loop architecture for robustness enhancement. The vector tracking loop implemented in this work is a vector delay lock loop (VDLL) structure.
The vector tracking loop architectures provide several important advantages as compared to the scalar tracking loops. One of the merits is that the tracking loop can be assisted positioning when satellite signal outage, which will be confirmed in the first part of this thesis. Nevertheless, they still suffer some fundamental drawbacks. The most significant drawback is that failure of tracking in one channel may affect the entire system and lead to loss of lock on all satellites. The other drawback is that errors in the navigation solutions may degrade the accuracy of the tracking loop results. For improvement of the vector tracking loop, a real-time receiver autonomous integrity monitoring algorithm is developed to prevent the error of one channel from spreading into the vector tracking loop. The Kalman filter based AIME is developed to enhance the vector tracking loop robustness. The AIME is used to check the possible fault in the pseudorange and the pseudorange rate. Furthermore, the fault detection and exclusion mechanism will be employed for excluding the abnormal satellite signal.
The result shows that the FDE has been successfully incorporated into the vector tracking loop to prevent the failure of one channel from spreading into the entire tracking loop. Performance evaluation for the proposed method will be carried out. The feasibility of the proposed method is confirmed. The results confirm that the vector tracking loops will not loss of lock on all satellites due to one channel failure.
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