BOC（binary offset carrier）modulation will be widely used in satellite navigation systems. The data and pilot channel of GPS L1C signal was modulated with the BOC (1, 1) and the TMBOC (time-multiplex binary offset carrier) modulation. The discrimination curve of TMBOC modulated signal was characterized with bias when using CCRW (code correlation reference wave) technique. In order to eliminate the tracking bias, an unbiased multipath mitigation technique was proposed. The novel technique generated two categories of local wave for the BOC (1, 1) and BOC (6,1) modulated component respectively, and its discrimination output was zero when there was no code phase bias. The technique can obtain unbiased tracking and a better accuracy because of the better utilization of BOC (6, 1) signal component.