Wavelet analysis: multipath mitigation from GPS carrier phase observation: article / Mohd Rijal Shukri

Multipath mitigation techniques using wavelet decomposition is proposed for extracting or modeling multipath from Global Positioning System (GPS) carrier phase observations. Multipath is a phenomenon whereby satellite signals can arrive at the receiver via multiple paths, due to reflections from nearby objects such as trees, buildings, the ground, water surfaces, vehicles, etc. Wavelet transform (WT) is a new tool for signal analysis that can provide simultaneously, time and frequency information of a signal sequence. Double Differencing (DD) technique was used to detect the multipath effect and the quality of GPS data was checked by using TEQC software.The wavelet technique Symlets(sym4) was used to perform the wavelet transform and de-noising the signal by using thresholding. GPS data which in RINEX format that supplied by JUPEM (Department Of Survey and Mapping Malaysia) and taken from receiver station located at Wisma Tanah Kuala Lumpur (3° 10' N, 101° 43' E) KTPK station and Universiti Putra Malaysia(2°59' N, 101° 43' E) UPMS station on 8 November 2005. The DD multipath and wavelet decomposition is visualized using MatLab software. The results indicate that the proposed method is effective to reduce carrier-phase multipath effect.