INTERFEROMETRIC GRAVITY GRADIOMETER INCORPORATING RETROREFLECTORS AND MEANS TO CORRECT FOR THEIR RELATIVE SHIFTING

摘要

Apparatus for measuring gravity gradients directly. Two retroreflectors are caused to experience free flight, and the radiation reflected by these retroreflectors during free flight is directed to a radiation receiver which senses and measures the temporal variations of intensity of the interfering reflected radiation beams. The time rate of change of the frequency of the output signal of the receiver is directly related to the vertical gradient of gravity. The instrument of this invention has means to correct for any shifting of the retroreflectors relative to each other and to the radiation beam in planes normal to the radiation beam.