Performance Analysis of a NavIC Aided Multi-GNSS Receiver in Low Latitude Region

Global navigation satellite systems (GNSS) play a vital role in positioning navigation and timing solutions across range of applications. This study focuses on analysing the accuracy and precision of Position, Velocity and Timing (PVT) solutions using a multi frequency, multi constellation GNSS receiver with a particular focus on the Indian Regional Navigation Satellite System (IRNSS) or Navigation with Indian Constellation (NavIC). Data is collected at the GNSS lab in Ramaiah Institute of Technology (RIT) located in the Bengaluru urban region during the months of May-August 2024 using the ELENA R1B GNSS module and the ELENA ELNAA3A tri-band antenna at a sampling frequency of 1 Hz. This study presents a performance evaluation of multi-constellation GNSS data, focusing on key positioning accuracy metrics Signal-to-Noise Ratio (SNR), Circular Error Probable (CEP), Distance Root Mean Square (2DRMS), and Spherical Error Probable (SEP) across eight epochs using data from NavIC, GPS, and GLONASS. The analysis emphasizes the role of satellite geometry, particularly Vertical Dilution of Precision (VDOP) and Position Dilution of Precision (PDOP), and SNR in influencing spatial accuracy. Results show that NavIC and GPS consistently deliver stable SNR (~43 dB-Hz and ~41 dB-Hz, respectively), while GLONASS exhibited greater variability, affecting accuracy in select epochs. The lowest CEP (0.42 m) and 2DRMS (1.02 m) occurred under optimal geometry (VDOP ≤ 0.85), while highest errors CEP of 1.33 m and SEP of 2.32 m were recorded when PDOP exceeded 1.06. Despite minor fluctuations in geometry and signal quality, positioning metrics remained reliable, with SEP generally below 2.5 m, indicating the robustness of multi-GNSS integration.