A new method for GPS signal tracking is being proposed. The method differs from conventional delay-locked loops, frequency/phase-locked loops and is based on calculation of a narrow-band signal correlation function in time-frequency domain. The method allows to track both line-of-sight signal and reflected GNSS signals, which cause serious degradation of positioning accuracy in urban environments. The method is targeted at mobile user under severe multipath propagation conditions, when reflected signal power is comparable to the power of line-of-sight signal.