Satellite-to-Satellite Range-Rate Measurement

Abstract

The measurement of range rate between two low-orbiting spacecraft with a precision of better than 1 μm/s provides a means for sensing global gravity variability. An analysis is given to show the conditions under which this precision can be realized, with emphasis on the requirements of NASA's Geopotential Research Mission. Experimental results obtained with a millimeter-wave demonstration system are presented along with a proposed design for a spaceborne instrument.