Error Analysis Of Absolute Gravimeter And Application Of Gravimeter In Study Of Speed Of Gravity

Absolute gravimeter, which is not only an important geophysical instrument, but also has a wide range of applications in many fields, such as metrology or experimental physics, is an extremely important science instrument. Because there is no primary standard for the earth gravitational field, so a calibration of absolute gravimeter is impossible and a detailed uncertainty budget, which is the basic of the instrument development, maintenance and data analysis, is needed.This paper based on the FG5 absolute gravimeter, starting from the instrumental principle and structure, summarized the main error sources of free-fall absolute gravimeter. After that, this paper proposed a new method of absolute gravity measurement:when the condition is suitable, hang the dropping chamber on to roof can eliminates most of the errors caused by releasing the test mass and improves the accuracy more or less.On the other hand, this paper, put the application of absolute gravimeter as the starting point, discussed whether gravimeters can be used in a new research field:the speed of gravity. Only two speed modes were discussed:preferred frame and Pseudo-retarded potential. The gravity expression of sphere with uniform speed and stratified density distribution in the preferred frame was given, and the expression of rotating sphere with uniform density in the other condition was deduced respectively. When the speed of gravity has a preferred frame, earth's rotation will change the angle between the ground point's position vector and the earth's velocity vector, hence, produce a gravitational fluctuation that can be measured by gravimeter. According to the orbital data of earth and the binary pulsar PSR1534 +12, Flandern T. gave two estimated values of the gravity speed. Based on the solar system's linear velocity in the galaxy and a stratified earth density model, this paper calculated the gravitational fluctuation with Flandern's two values. The result showed that the gravitational fluctuation in a rotation period is about two or three orders of magnitude lower than the most sensitive instrument's accuracy. With the improvement of measure accuracy, it is may be possible to verify Flandern's model directly in the future. And if the gravity field is similar to the retarded potential(rough approximation of general relativity), there will be no fluctuation that can be measured by the gravimeter(or too small to measure), but gravity anomaly of rotating sphere with uniform density was deduced. The binary pulsar PSR1913+16's gravity anomaly was calculated, which lay the foundation for further work with astrodynamics.