Global Navigation Satellite Systems and Indian Defence Research - A Review

In this paper an attempt has been made to review the evolution of Global Navigation Satellite System (GNSS) towards a Multi-GNSS environment through global and regional existing systems and initiation of new systems and its impact on the Indian Defence Research with special focus on the Missile Development Program in Defence Research and Development Organization (DRDO). The various components of stage wise GNSS evolution, the availability of the satellites in the Indian Sub-continent, signal availabilityand reliability of the various constellations and its effect on missile development program has been highlighted in this paper starting from the first use of United States-developed Global Positioning System (GPS). This paper also comments on the possible future use of GNSS in Indian Missile Development Program with introduction of other such systems-GLONASS, Galileo, BEIDOU and Regional Based Navigation Systems QZSS of Japan and IRNSS/NAVIC, the Indian System.