Performance Analysis of Multi-GNSS System

Global Navigation Satellite System (GNSS) is basically a system of satellites providing autonomous geo spatial positioning with global coverage. There are mainly four GNSS systems currently in operation. They are the United States¿ Global Positioning System (GPS), Russian Federation's Global Orbiting Navigation Satellite System (GLONASS), Chinese BeiDou Navigation Satellite System (BDS) and European Galileo. Navigation basically means any of several methods of determining or planning an object¿s position and course by geometry, astronomy, radio signals etc. This combines two concepts. The first is the determination of the position and velocity of a moving body with respect to a known reference, sometimes known as the science of navigation. The second is the planning and maintenance of a course from one location to another while avoiding obstacles and collisions. GNSS constellation is very important in determining these things. More precisely the Dilution of Precision plays a vital role in accuracy of the navigation system.