DopplerTracking
Doppler tracking is a technique used to determine the velocity of a moving object along the line of sight by measuring the Doppler shift of radio signals exchanged between a ground station and the object, typically a spacecraft or satellite. It relies on the fact that motion toward or away from the observer changes the frequency of the received signal.
Principle: If a transmitted frequency is f_t and the received frequency is f_r, the Doppler shift Δf
Technique: A stable oscillator on the ground and a coherent transponder on the spacecraft generate a measurable
Applications: Spacecraft navigation and mission operations, satellite orbit tracking, geodesy, and time-transfer experiments. The method is
Challenges: Atmospheric delays in the ionosphere and troposphere, solar plasma effects, clock stability, and geometric geometry