To provide a position measurement/communication composite type autonomous satellite constellation capable of concurrently offering position measurement/ moving body communication services to moving bodies scattered on the earth by concurrently using two satellite groups located at different orbit altitudes.

This autonomous satellite constellation uses two satellite groups of a high-altitude G-group satellite group 101 and a low-altitude L-group satellite group 102 lower than the G-group of geostationary satellites, transmits time-synchronized distance measuring radio waves 103, 104, relays radio waves between a moving body 105 and a ground fixed station 106, and offers position measurement/communication composite services to the moving body. The distance measuring radio waves 103, 104 transmitted from both the G-group and L-group are received and processed, and the time reference of the satellites of the L-group is synchronized with the time reference of the satellites of the G-group. The clock offset and the momentary position are autonomously determined when the incoming time of the distance measuring radio waves from the G-group is measured, the L-group is also used as a distance measuring radio wave source, relay means are mounted on the L-group, and the position measurement/communication services are offered to the moving body 105.