A New Tracking Technique with the Memory Discriminator for High Sensitivity GNSS Receivers

In this paper, a new discriminator is presented. This method combines a frequency discriminator named Differential Amplitude (DA) and a moving window function. DA was specially designed for enhanced sensitivity tracking of Global Navigation Satellite Systems (GNSS) signals. And the window function is used to select different portions of the carrier Doppler measurements. This combination, named memory discriminator, can improve the quality of Doppler estimates by reducing the variance of the measurements. In this way, the discriminator can reduce noise and hence achieve better tracking performance. Performance comparisons tested by using live GPS data have been made between the proposed method and the traditional ones, which include frequency-locked loop (FLL) assisted phase-locked loop (PLL), FLL and DA. Simulation curves indicate that the presented method has a remarkable advantage over other algorithms.