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Wavelet packets based denoising method for measurement domain repeat-time multipath filtering in GPS static high-precision positioning

Lau, Lawrence

Authors

Lawrence Lau



Abstract

Repeatable satellite orbits can be used for multipath mitigation in GPS-based deformation monitoring and other high-precision GPS applications that involve continuous observation with static antennas. Multipath signals at a static station repeat when the GPS constellation repeats given the same site environment. Repeat-time multipath filtering techniques need noise reduction methods to remove the white noise in carrier phase measurement residuals in order to retrieve the carrier phase multipath corrections for the next day. We propose a generic and robust three-level wavelet packets based denoising method for repeat-time-based carrier phase multipath filtering in relative positioning; the method does not need tuning to work with different data sets. The proposed denoising method is tested rigorously and compared with two other denoising methods. Three rooftop data sets collected at the University of Nottingham Ningbo China and two data sets collected at three Southern California Integrated GPS Network high-rate stations are used in the performance assessment. Test results of the wavelet packets denoising method are compared with the results of the resistor–capacitor (RC) low-pass filter and the single-level discrete wavelet transform (DWT) denoising method. Multipath mitigation efficiency in carrier phase measurement domain is shown by spectrum analysis of two selected satellites in two data sets. The positioning performance of the repeat-time-based multipath filtering techniques is assessed. The results show that the performance of the three noise reduction techniques is about 1–46 % improvement on positioning accuracy when compared with no multipath filtering. The statistical results show that the wavelet packets based denoising method is always better than the RC filter by 2–4 %, and better than the DWT method by 6–15 %. These results suggest that the proposed wavelet packets based denoising method is better than both the DWT method and the relatively simple RC low-pass filter for noise reduction in multipath filtering. However, the wavelet packets based denoising method is not significantly better than the RC filter.

Journal Article Type Article
Publication Date Apr 30, 2017
Journal GPS Solutions
Print ISSN 1080-5370
Electronic ISSN 1521-1886
Publisher BMC
Peer Reviewed Peer Reviewed
Volume 21
Issue 2
Pages 461-474
APA6 Citation Lau, L. (2017). Wavelet packets based denoising method for measurement domain repeat-time multipath filtering in GPS static high-precision positioning. GPS Solutions, 21(2), 461-474. doi:10.1007/s10291-016-0533-1
DOI https://doi.org/10.1007/s10291-016-0533-1
Keywords Repeat-time-based multipath filtering, Denoising, Wavelet packets, Multipath mitigation, Discrete wavelet transform (DWT), Sidereal filter
Publisher URL http://dx.doi.org/10.1007/s10291-016-0533-1
Copyright Statement Copyright information regarding this work can be found at the following address: http://creativecommons.org/licenses/by/4.0
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Copyright Statement
Copyright information regarding this work can be found at the following address: http://creativecommons.org/licenses/by/4.0



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