The Nature of Astro Doppler Velocity Measurement

This paper deals with astro Doppler velocity measurement for space vehicle navigation. The measurement yields the relative velocity of the vehicle with respect to a star, and requires the use of electro-optical systems capable of measuring a small incremental change in the wavelength of propagated stellar energy. Such systems provide velocity data whose character and limitations are a function of the star's spectral radiation as well as the system instrumentation. This paper discusses the astro velocity data, its derivation, character, and limitations; and the Doppler velocity systems, their capabilities, limitations, and possible instrumentation.