A non-coherent architecture for GNSS digital tracking loops

In this paper a new non-coherent architecture for GNSS tracking loops is proposed and analyzed. A non-coherent phase discriminator, able to extend the integration time beyond the bit duration is derived from the Maximum Likelihood principle and integrated into a Costas loop. The discriminator is non-coherent in the sense that the bit information is removed by using a non-linear operation. By jointly using such a discriminator and non-coherent integrations at the Delay Lock Loop level, a fully non-coherent architecture, able to operate at low carrier-power-to-noise density ratio (C/N0), is obtained. The algorithms proposed have been tested by means of live GPS data and compared with existing methodologies, resulting in an effective solution for extending the total integration time.