Ascertaining earth's gravitational field from on-board aircraft - continuously measuring acceleration and integrating resultant signal twice to derive signal resembling height

摘要

The height-resembling signal derived from integrating the acceleration signal twice is compared with the height signal from a permanent separate height measurer. The difference signal is used as a direct measure for the change of the earth's gravitation vector. By calibrating the superimposed system errors arising chiefly from the instrumentation employed, errors are eliminated. As well as the interference acceleration related to flight path conditions, the centripetal and Coriolis accelerations are compensated. The compensation is achieved by a series circuit of sensor dynamic and model providing delays of the complete system. The path shift between the original signal and display deriving from these delays is completely eliminated by off-line post-processing.