Preliminary Investigation of Generation of US-Based GPS Signal

Abstract

Global Navigation Satellite System (GNSS) generates signals using constellation of satellites from space. The GNSS signals transmit positioning and timing information to GNSS receiver. These receivers use this information to determine their location. There are various GNSSs being developed across the world. They are the United States Global Positioning System, Russia’s GLONASS, Europe’s GALILEO, China’s BeiDou, Japan’s QZNSS, and India’s IRNSS. Among these, GPS, GLONASS, and GALILEO have the global coverage and BeiDou-I, QZNSS, and IRNSS have the regional coverage. Among all the GNSS, GPS and GLONASS are in operation, whereas all other systems are in the development stage. GPS is a fully developed U.S. Space-based satellite navigation system, which provides its services to the military as well as civilian users. Generally, GPS uses four satellites to find the position of receiver. GPS transmit signals in L-band (1–2 GHz). The two basic GPS signals are L1 (1575.42 MHz) and L2 signals (1227.6 MHz). There are various applications of GPS like location-based services, surveying, mapping, space and military applications, etc. Also, GPS has few limitations such that it cannot work well in underground, underwater, city with tall buildings, indoor regions, etc. In this paper, the generation of GPS signals by the development of software code is presented.