Computer program to reduce precise gravity observations

8 refs

A FORTRAN computer program has been developed to compute the relative values of gravity between points at which observations have been made with gravity meters. The program allows for the simultaneous computation by least squares of the relative gravity at the points, the drifts and base values of the gravity meters, the scale factors of the gravity meters, the tidal amplification, the effects of air pressure and temperature on the gravity or gravity meters, and, if the readings are made over a period of time, the secular change of gravity at the individual points. The readings themselves, and not the difference of successive readings, are used for the the observation equations which may be weighted both in groups for each day, survey, or gravity meter, and individually, depending on the residual of the observation. In general the analysis of the gravity meter observations gives the ratio of the differences of gravity between each of two stations and a third. If the appropriate scaling is made this approximates to the differences of gravity at the points from that at one chosen point or from the mean gravity value at all the points. Secular change of the gravity ratios is similarly determined if readings have been made over a period of time. When more than one gravity meter has been used, or the readings over a period of time have been made using only one meter, so that the scale factor may have changed, the relative scale factors of the meters may be determined (auth)

GP