Abstract: The Indian Regional Navigation Satellite System (IRNSS) and Quasi-Zenith Satellite System (QZSS) are two Regional Navigation Satellite Systems (RNSSs) announced as fully operational in recent years. In this contribution, stand-alone L5 single point positioning (SPP) performances of IRNSS and QZSS are first assessed in their primary service areas. Then, the performance of each RNSS assisting GPS positioning with satellite cut-off elevation angles set at 5°, 15°, 25°, 35°, 45°, and 55° in its primary service area is compared and analyzed in detail. It is to examine to what extent the constellation configuration difference can affect the performance of each RNSS assisting GPS positioning in the urban canyon environment. The results demonstrate that:① IRNSS can provide 24-hour continuous independent L5 positioning service with a positioning accuracy of <2.50 m in horizontal, and <4.10 m in vertical in its primary service area; ② QZSS can only provide independent L5 positioning service of limited availability with a positioning accuracy of <4.80 m in horizontal, and <7.40 m in vertical in its primary service area; ③ the performance of QZSS assisting GPS positioning in the urban canyon environment in mainland Japan is better than that of IRNSS in its primary service area, especially in the situation of a limited sky view, due to its unique constellation configuration. The finding of this study could inspire the policy-makers when they are designing a new RNSS.

Key words: IRNSS, QZSS, the primary service area, stand-alone positioning, assist GPS positioning, urban canyon environment, L5 signal