Implementation of a Multi-frequency, Multi-constellation and Real-time GNSS Software Receiver Using Dual Channel USRP

In this paper, we implemented and verified a real-time GNSS software receiver supporting multi-frequency and multiconstellation using dual channel USRP. In order to reduce the amount of data of the signal, GPS, GLONASS, and BDS signals were combined into a wide band and received at one time. By using the dual channel USRP, five GNSS signals in the upper Lband and the lower L-band can be simultaneously received. We designed the data flow and receiver structure to process the converted digital IF signal through USRP. The designed receiver is implemented in real time through GPU computing and multi-thread processing. In order to verify the performance of the implemented software receiver, real - time operation performance and navigation results were confirmed using live signals. As a result, it consumes 75% of computation time and processed in real time when processing 40 satellite signals. A precision of the position was measured at 5.8m for 2dRMS and about 1.7m for CEP. The GNSS software receiver implemented in this paper is expected to be used in future studies of multifrequency and multi-constellation related algorithms.