<human>:  I have a question about GPS and GNSS. Who invented GPS?
<bot>: The Global Positioning System was invented by the US Department of Defense in the 1970s. It was originally called the NAVSTAR Global Positioning System, but was renamed GPS in 1983. The system is made up of a constellation of satellites that orbit the Earth at an altitude of about 11,000 miles. The satellites transmit signals that allow users to determine their location on Earth.