Orientation of Measurement Sensors for Optimum End-of-Life Performance

Relative orientations of on-board measurement sensors are found that ensure the best possible measurement accuracy in the end-of-life situation when all but three sensors have failed. For five and six sensors, the optimum orientations are, respectively, the single cone and dodecahedron configurations. For seven and eight sensors, new configurations are found that are, respectively, 25 and 20 percent more accutate than previously proposed configurations. In general, there is a tradeoff between performance at end-of-life and performance earlier in a configuration's lifetime.