The Indian Regional Navigation Satellite System (IRNSS) is an autonomous and independent navigational system being developed by India. IRNSS will provide position, navigation and timing services for national applications. To improve accuracy, it can be augmented using GPS and pseudolites (pseudo-satellites). In this paper, the effect on DOP (Dilution of Precision) due to augmentation of the proposed constellation of IRNSS with pseudolites is investigated. GDOP is reduced to 1·75 (max) from 3·63 (max) due to augmentation of IRNSS with two airport pseudolites (APLs). Due to augmentation of IRNSS with GPS, GDOP is reduced to 2·4 (max). When IRNSS is augmented with an APL as well as with GPS, GDOP is further decreased to 1·65 (max). The regional effect on DOP due to IRNSS is also investigated at different locations in the Indian region.
