Review of Artificial Satellite Gravity Gradiometer Techniques for Geodesy.
HUGHES RESEARCH LABS MALIBU CA
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This paper reviews the development status of gravity gradiometer instrumentation and the utilization of these gradiometers in earth orbiting artificial satellites for geodesy. Recent studies have shown that gravity gradiometers in artificial satellites operated in a low altitude polar orbit could produce in 20 to 30 days a complete map of the higher order harmonics 25 to 75 degree and order of the earths gravity field provided the instrumentation flown has a sensitivity of 0.01 EU 10 to the minus 11 sec to the -2 1 ngalm for a 35 sec integration time. During the past decade gravity gradiometer development efforts have produced instrumentation which have measured gravity gradients in the laboratory and in orbit and which can be made to operate at the 0.01 EU sensitivity level in an orbital environment. Special emphasis is placed on the instrument concepts that can easily be increased in size from their present configuration to obtain the desired sensor signal-to-noise and which use spacecraft rotation modulation of the gravity gradient signal to aid in reducing externally generated noise to below the 0.01 EU level. Author