Introduction to GPS/GNSS technology

Abstract Satellite-based navigation systems are one of the most indispensable technologies in the present-day world that have made a vast improvement since the day of its inception due to global availability of signal and performance. It allows measuring positions in real time with an accuracy of up to a few centimeters on the Earth. The advent of Global Positioning System (GPS) has led to technological revolutions in highly accurate navigation, positioning, and time that is being applied in various civilian, military, and scientific purposes. GPS works on the radio waves that are being transmitted from a space-based group of satellites to the terrestrial GPS receiver to deduce the exact position of the Earth. Although there are various errors related to clock errors, multipath error, receiver noise, and antenna phase center variations at satellite as well as receivers end, it is being resolved through technological advancement and methods. Incorporating both GPS and GLONASS constellations in the navigation system may significantly improve the accuracy of the navigational solution. This chapter aims to discuss the various concepts of GPS, including working principle, various errors, various Global Navigation Satellite System technologies evolving from GPS to Quasi-Zenith Satellite System, and its vivid applications.