Navigation satellite constellations

American satellite-based radio navigation service

European global navigation satellite system

The Global Navigation Satellite System (), usually referred to by the acronym GLONASS (, ), is a Russian satellite navigation system operating as part of a radionavigation-satellite service. It provides an alternative to the Global Positioning System (GPS) and was the second navigational system in operation with global coverage and of comparable precision.

The BeiDou Navigation Satellite System (BDS; ) is a satellite-based radio navigation system owned and operated by the China National Space Administration. It provides geolocation and time information to a BDS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more BDS satellites. It does not require the user to transmit any data and operates independently of any telephonic or Internet reception, though these technologies can enhance the usefulness of the BDS positioning information.

Indian satellite-based GNSS augmentation system

satellite navigation system

Japanese satellite navigation system

Tsikada ( meaning cicada) was a Soviet satellite navigation system including ten Low Earth Orbit (LEO) satellites. It transmitted the same two carrier frequencies as the U.S. TRANSIT satellite system. The first satellite was launched in 1974.

satellite

satellite constellation

thumb|The Naval Research Laboratory’s managers for the Timation program and, later, the GPS program: [[Roger L. Easton (left) and Al Bartholomew.]] thumb|Timation 1 (rectangular object in center of photo), launched May 31, 1967, tested in a "piggyback" launch aboard an Air Force Thor-Agena D rocket The Timation satellites were conceived, developed, and launched by the United States Naval Research Laboratory in Washington, D.C. beginning in 1964. The concept of Timation was to broadcast an accurate time reference for use as a ranging signal to receivers on the ground.