Evaluation of Positional Performance of NavIC Software Receiver with Inertial Sensor Measurements

GNSS is the most popular navigation system, used for positioning and timing applications. The performance of the GNSS receiver is degraded in harsh and challenging environments, where the GNSS signals are completely or partially blocked by trees, tunnels, canopy, flyovers etc. The performance of the receiver can be improved using external navigational aids, thereby it overcomes the limitations posed in the abnormal environments. Inertial Navigation System (INS) is the most popular and efficient aid to GNSS, as they are complimentary in nature. Nowadays, GNSS software receiver is proved to be very useful tool for the GNSS research, development and navigation related applications. Aiding GNSS software receiver with INS is very much useful for GNSS/INS related research.The performance of the existing NavIC software receiver (NavICSR) with a low-cost MEMS-IMU as an external aid is reported in this paper. NavICSR was developed at NERTU and it is integrated with MEMS-IMU in a loosely coupled mode. First, the integration algorithm is validated using the simulated data obtained using Skydel GNSS simulation software, which generates data for both NavIC IF signals and IMU measurements. Further, it is evaluated with measured data from low-cost RTL-SDR front-end for NavIC signals and BMI160 for low-cost MEMS based IMU measurements. The simulation results shows that 3D-RMSE of NavICSR is reduced by 65.59% for simulated data and 67.93% for real data after integrating with the low-cost MEMS based INS. This study help us to further develop new algorithms for autonomous navigation and their evaluation using the presently available NavICSR and GNSS Skydel or any other simulator that can generate NavIC and IMU measurements.