Measurement of variation of temperature with infrared shadow sensor

In the gravitational experiments and measurements of earth tide, various interferences should be carefully considered because of the weakness of the signal. The variation of temperature is one of the most important interferences. To minimize the temperature effects, all the laboratories concerned are located in the underground where the temperature is very steady. In spite of that, it is still necessary to measure the variation of environmental temperature, especially daily changes of the temperature. By means of that,we can subtract the temperature effect from the original data recorded, and greatly improve the final experiment result.