Some are unaware of this but the GPS that we normally use here in America is not the same navigation system used around the globe. The GPS was developed by the US and other countries such as Russia, China, India, and so forth have their own navigation systems set up. These navigation systems as a whole are called Global Navigation Satellite Systems. Each system has their own name. Russia to GLONASS, China to BeiDou, India to NavIC, QZSS, and the European Union to Galileo.
Each GNSS have their own number of satellites in orbit and provide navigation for different areas with respect to the country that launched it. In this brief, the United States' GPS will be the primary topic focused on. First going into the history of the Global Positioning System dating back to the 1960's.