Deep space tracking and frequency standards

A number of applications of spacecraft tracking measurements are presented, along with discussions of how these measurements depend on frequency and timing. Requirements imposed by tracking are identified for the station frequency reference in terms of timing, stability, and spectral purity. Requirements are identified for the spacecraft on board oscillator, and requirements are identified for interstation time and frequency synchronization. The fundamental form of the effects of clock epoch offset, clock rate offset, and clock instability on Doppler, range, and interferometric tracking observables is presented. Examples are given of tracking techniques which are currently limited by the performance of frequency standards