Navigation is a universal problem whenever one needs to go from point A to point B. Around Earth's orbit, Global Navigation Satellite Systems (GNSS) such as the American Global Positioning System (GPS) or the Russian GLObal Navigation Satellite System (GLONASS) have Pulsar positioning systems: a quest for evidence of extraterrestrial engineering, boats, cars, and pedestrians navigate. GPS did not appear overnight but was the culminating outcome of ground-based radio navigation in the 1920s, gradually complemented by satellites.
