Gradiometry Attitude Determination System

A program leading to the definition of a spaceborne attitude determination system based upon gravity field measurements is proposed. The specific innovation involves processing gravity gradient measurements from a network of accelerometers. Precision determination of attitude (0.003 degrees) can be expected at an update rate of 10 Hz. This project addresses the need for a high-accuracy, low-cost, low-power, and low-mass attitude determination system for use on-board spacecraft, in particular small momentum biased, nadir pointing satellites. The proposed systems engineering consists of six tasks: 1) measurement error analysis, 2) attitude determination accuracy definition, 3) gradiometer survey and system electronic design definition, 4) requirements for the satellite hardware suite, 5) attitude determination flight software specifications, 6) planning for a proof-of-concept demonstration to be executed under Phase II. The expected benefits to NASA are numerous with the current trend toward development of small, low-cost satellites.