数字重力仪高精度恒温测温系统设计与测试研究

高精度数字重力仪广泛应用于矿产资源勘探领域，由石英弹性系统组成的重力传感器是高精度数字重力仪的核心部件，其对外界环境温度非常敏感，由环境温度变化引起的重力输出变化远远大于仪器本身精度指标，而且不同的数字重力仪具有不同的温度影响特性.若重力传感器的恒温环境得不到保障，或环境温度的微弱变化无法得到准确的测量和补偿，将严重影响重力仪器的测量精度和一致性.本文针对该问题，研究了高精度恒温测温系统的设计方法及关键技术，考虑到数字重力仪器精度高、体积小、功耗低和便携式的特点，对高精度恒温测温系统中的关键器件选型、热结构设计、电路设计、软件设计等进行深入研究，并给出具体的解决措施.并设计了静态试验、高低温试验和石英弹性系统温度系数测定试验三个部分验证高精度恒温测温系统的有效性.试验结果表明：高精度测温系统最小分辨率达到10 μ℃；静态常温时，高精度恒温系统温度变化约为70 μ℃；在-20℃~+45℃的环境温度冲击中高精度恒温系统温度变化小于1 m℃；恒温点微调装置可实现石英弹性系统温度系数的精确测定.该研究为高精度重力测量仪器研制中消除环境温度变化影响提供了一种有效解决方案.

Design and tests of the high-precision temperature control and measurement system in the digital gravimeter

The high-precision digital gravimeter is widely used in mineral resources exploration. The gravity sensor composed of quartz elastic system, the core part of this instrument, is very sensitive to the ambient temperature. The change of gravity caused by the change of ambient temperature is much greater than the accuracy of the instrument proper, while such a property varies with different instruments. If the thermostatic environment of the gravity sensor is not guaranteed, or the weak change of the ambient temperature cannot be accurately measured and compensated, the measurement accuracy and consistency of the gravimeter will be seriously affected. To solve this problem, this work studies the design method and key technology of high precision temperature control and measurement system in this instrument. Considering the characteristics of the digital gravimeter such as high precision, small volume, low power consumption and portable manner, this work makes an exhaustive analysis on the key device selection, thermal structure, circuit and software in the high-precision temperature control and measurement system, and gives specific solutions. Tests on three aspects, i.e. static operation, high and low temperature conditions, and the temperature coefficient of the quartz elastic system, are conducted to verify the performance of this system. The results show that this high-precision temperature measurement system reaches the resolution of 10 μ℃; its temperature changes by 70 μ℃ in the constant temperature and less than 1 m℃ in the ambient temperature range -20℃ to +45℃; and accurate determination of quartz elastic system's temperature coefficient can be achieved by the temperature controlled trimming device. This study provides an effective solution to eliminate the influence of environmental temperature change in the development of high-precision gravity measurement instruments.