Tightly coupled MEMS INS/GPS integration with INS aided receiver tracking loops

Date
2008
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Abstract
Global Positioning System (GPS) receiver positioning capabilities are being challenged by increasing requirements on positioning and navigation under environments with GPS attenuated signal. This dissertation focuses on the performance enhancement of MEMS INS/GPS integrated navigation systems in signal-attenuated environments. MEMS INS/GPS tightly coup led integration with INS Doppler aided carrier tracking loops is studied in this dissertation. Based on an analysis of the conventional carrier tracking loop, carrier tracking capability is enhanced by using INS Doppler aiding. INS aided tracking is implemented by adding INS Doppler estimates to the receiver NCO. To theoretically analyze the performance of aided tracking loop, an IS signal simulator is developed. With helps from the simulator, the analysis concludes that INS aiding can effectively improve a standard GPS receiver tracking performance in weak signals and high dynamics environments. An EKF based MEMS I S/GPS tight integration scheme is used to control aiding errors from a MEMS based INS to the tracking loop. The tightly coupled INS/GPS can work well under the environment of fewer than four satellites. By using non-holonomic constraint for land vehicle applications, the position accuracy can be improved by around 60%. Furthermore, a novel pseudo-signal generation method is proposed to fulfill one gyro and 2 accelero meter. ( I G2A) suboptima l INS configuration . The proposed suboptimal I S/GPS tight integration can maintain the system poitioning enor within 7m, 27m, 38m, or 40m durin g 30s GPS signal outages, with 3, 2, l or O satellite(s) inview, respectively. With the error control by an EKF with INS/GPS tight scheme, MEMS INS Doppler aiding can achieve an additional 3dB - H z margin for the receiver signal tracking, allowing signals with power as weak as 24dB - H z . Furthermore, compared with the conventional tight integration, the position accuracy of the tight INS/GPS integration with aided tracking loops is improved under attenuated signal environments.
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Bibilography: p. 162-173
some pages are in colour
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Citation
Yang, Y. (2008). Tightly coupled MEMS INS/GPS integration with INS aided receiver tracking loops (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/2130
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