Optimal Doppler-Aided Autonomous Position with a Flexible Smoothing Window Width

X. Liu, S. Yang, J. Yang, P. Lu

Abstract:	Outstanding performance of global positioning system(GPS) in outdoor scenarios is pushing people across the globe to extend its applicability to signal degraded environments. However, the operation of a standard GPS receiver under such harsh environments is limited by the complex nature of signal propagation phenomena such as multipath and shadowing. Doppler-Aided Autonomous Positioning is a simple combination procedure of the noisy code-based pseudorange measurements and the receiver generated Doppler measurements. The objective is to smooth the code pseudoranges and push the accuracy of the code-based absolute positioning in a single-receiver autonomous mode in urban areas. This method is an alternative to the Hatch filter with the aim of improving positioning accuracy in difficult environments where the traditional Hatch filter fails. In principle the larger a smoothing window width is used in the filtering process, the more precise the smoothed pseudorange should become. Some researchers suggest that 100-epoch-window is acceptable for the smoothing width of Doppler-Aided Autonomous Positioning , but it is just an empirical value, not an optimal one. In addition, this value is not always true to the other countries. The ionospheric divergence effect between code and carrier increases with smoothing window width, this paper suggests a new algorithm on Doppler-Aided Autonomous Positioning whose smoothing window width varies flexibly depending on the regional, diurnal, and seasonal ionospheric variation. We can find the best number by a simple equation. Moreover we can apply this algorithm to the each measurement so that we construct SEUGPS system using the optimal Doppler-Aided algorithm. From the data process result and real time experiment, we found that the position accuracy of the optimal algorithm is more accurate and robuster than that of traditional method.
Published in:	Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013) September 16 - 20, 2013 Nashville Convention Center, Nashville, Tennessee Nashville, TN
Pages:	3521 - 3527
Cite this article:	Liu, X., Yang, S., Yang, J., Lu, P., "Optimal Doppler-Aided Autonomous Position with a Flexible Smoothing Window Width," Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013), Nashville, TN, September 2013, pp. 3521-3527.
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