Augmentation of GNSS utility by IRNSS/NavIC constellation over the Indian region

Abstract Indian region is expected to receive signal from multiple satellite-based navigation systems for multi-GNSS hybrid operation. Even in presence of GPS, GLONASS and GALILEO signals together, it is regularly found that, during some parts of the day no GNSS satellite is available above 60° elevation angle from large parts of India. This may cause problem in seamless navigation solutions in the locations, where visibility of the satellites is also obstructed in the lower elevation angles, which is a common feature in Indian urban conditions; the situation also degrades satellite geometry. IRNSS/NavIC is Indian indigenous regional navigation system operational since 2016. This paper presents theoretical, simulated and initial results of real-time studies on IRNSS/NavIC visibility from India using a IRNSS-GPS-SBAS (IGS) receiver. The studies show that, in such situations of inferior GNSS satellite visibility, IRNSS/NavIC operating together with GPS, can augment this time-dependent degraded visibility conditions. The Indian satellite navigation system ensures presence of at least one satellite above 60° elevation for use with GPS over the Indian region, supports multi-GNSS operation towards seamless solution, and improves satellite geometry.