A multi-frequency GPS and NavIC reflectometry receiver using commercially off-the-shelf SDR

GNSS-R is a passive remote sensing technique that uses Earth-reflected GNSS signals to study the Earth’s geophysical parameters. It is a cost-effective complement of existing remote sensing techniques and provides 24-hour coverage due to the continuous availability of satellite signals. This research work introduces a multi-constellation and multi-frequency GNSS-R receiver. The proposed reflectometry receiver has three components: a broadband GNSS antenna for receiving GPS-L1 and NavIC-L5 RHCP and LHCP signals, an SDR which is used as a frontend to receive, down-convert and digitise the received GNSS RF signals, and a single board computer to process the received GNSS signal on-board the receiver platform. The functional verification of the Hardware-in-Loop (HIL) simulation of the designed receiver is achieved by comparing its results with the numerical simulation results. After numerical and HIL verification a set of field-experiments are conducted to demonstrate that the proposed antenna and receiver hardware can successfully be used to acquire reflected GPS-L1, and NavIC-L5 signal and generate the DDMs onboard.