Carrier Tracking Two-way coherent communication Transmitter phase-locks to the received fre equency Transmitted frequency is a specific ratio of the uplink frequency Easy to find and measure the frequency received on the ground Doppler shift provides range rate October 29. 2003 Massachusetts Institute of TechnologyCarrier Tracking • Two-way coherent communication – Transmitter phase-locks to the received frequency – Transmitted frequency is a specific ratio of the uplink frequency • Easy to find and measure the frequency received on the ground • Doppler shift provides range rate October 29, 2003 Massachusetts Institute of Technology 5