US Patent 7406390 Accurate dynamic gravity measurement method and apparatus

Gravity information for a gravity survey is obtained by using an array of relative gravimeters whose relative gravity measurement signals have been calibrated by using an absolute gravimeter to approximate absolute gravity measurements. The absolute gravimeter is moved periodically to the location of each relative gravimeter to measure absolute gravity. The absolute and relative gravity measurements for each relative gravimeter form an error signal which is used to calibrate each relative gravimeter.