Doppler Shift from Earth-Orbiting Satellites

Doppler shift, which is easily observable as a change in frequency, is due to a change in the phase path between an emitter and observer over time.  The changing phase path contains information about the position of the emitter as well as the propagation medium.  This presentation describes an effort to estimate the Doppler shift of the now-defunct VO-52 (“HAMSAT”) satellite at 145 MHz and theoretical concepts of orbit determination by trilateration.  It is similar to work performed in the West during the early weeks of the Space Race that determined the orbit of Sputnik-I and led to the development of the satellite Doppler navigation (TRANSIT) technique.