Automatic Vertical Alignment of an Absolute Gravimeter by Detecting Displacement of the Measuring Beam

An automatic vertical alignment method is presented and analyzed for an absolute laser ballistic gravimeter. The method uses a high-speed video camera to record the displacement trajectory of glare from the measuring beam reflected from a corner reflector when the test body is in free fall. The magnitude and direction of the measuring beam displacement angle from the vertical is determined by frame-by-frame processing of the obtained video, and the vertical of the working gravimeter beam is corrected by actuators installed on the movable supports of the gravimeter base. Experimental verification showed that the vertical alignment error does not exceed 3 x 10(-5) rad.