The Thermal Analysis Of Rotating Gradiometer Measurement System

Rotating gravity gradiometer is sensitive to short-wave components of gravitational field by measuring the second order gradient of gravitational field unusual. Gravity gradiometer plays an important role in gravity survey, gravity aided navigation, resource exploration, land resource investigation and other fields. Measuring accuracy of gravity gradiometer is constrained by installation error of accelerometer, accuracy of accelerometer, environmental temperature, capability of stabilized platform. The temperature affecting the gradiometer measurement system is analyzed.First of all, this paper established the 3D model of the gradiometer measurement system based on the principle of rotating gravity gradiometer. Gravity gradient instrument(GGI) is the most sensitive to temperature by thermal analysis. Accelerometer as the core of the gravity gradiometer, its accuracy and stability determine the accuracy of GGI, the accelerometer bias and scale factor is strongly influenced by the temperature. The relation equation between the temperature coefficient of accelerometer scale factor and the output result are found by analyzing the 2f item and ignoring other items. In addition, the coupling relation equation between the accelerometer scale factor consistency and the disc rotating speed instability are found.Secondly, thermal cover is designed and the thermal simulation model is established. By taking level 3 temperature control measures can keep the temperature of accelerometer chip within 0.001℃. Thermal deformation has a little effect on installation error of accelerometer based on the results of thermal stress analysis.Lastly, designing the accelerometer temperature experiment and optimizing the simulation model based on the experimental results. The temperature difference between the results of simulation with the results of experiment is 0.1℃ around. By revising the results of simulation make temperature difference fall to-0.014℃. The temperature characteristic of circuits output result is get by analyzing the results of temperature experiment and provides theoretical basis for circuits’ temperature compensation.