It is well known that multipath disturbance is one of the major error sources impacting high precision GPS positioning. Even though most of the other error sources have been dealt with by modeling or using special practical techniques, multipath disturbance is still the limiting factor of all precise differential carrier-phase applications. Wavelet decomposition techniques proved to be a powerful tool in mitigation as introduced by various researchers. This paper presents a new trend extraction technique for multipath mitigation in carrier phase measurements domain using wavelet multi-resolution analysis.