Locus-based navigation Location-based Doppler techniques were also used in the U.S. Navy's historical Transit satellite navigation system, with satellite transmitters and ground-based receivers, and are currently used in the civilian Argos system, which uses satellite receivers and ground-based transmitters. In these cases, the ground stations are either stationary or slow-moving, and the Doppler offset being measured is caused by the relative motion between the ground station and the fast-moving satellite. The combination of Doppler offset and reception time can be used to generate a locus of locations that would have the measured offset at that intersects the Earth's surface at that moment: by combining this with other loci from measurements at other times, the true location of the ground station can be determined accurately.
Locus-based navigation Location-based Doppler techniques were also used in the U.S Navy's historical Transit satellite navigation system, with satellite transmitters and ground-based receivers, and are currently used in the civilian Argos system, which uses satellite receivers and ground-based transmitters. In these cases, the ground stations are either stationary or slow-moving, and the Doppler offset being measured is caused by the relative motion between the ground station and the fast-moving satellite The combination of Doppler offset and reception time can be used to generate a locus of locations that would have the measured offset at that intersects the Earth's surface at that moment: by combining this with other loci from measurements at other times the true location of the ground station can be determined accurately.