Design of a high-precision, high environmental adaptability temperature measurement system for environments with large temperature variations

A high-precision, high environmental adaptability thermometer based on proportional divider resistance is proposed for high-precision temperature measurement in a spaceborne environment subjected to large temperature variations. In this method, a constant voltage source was used instead of the traditional current source to increase the short-term stability of the proportional divider resistance measurement. The temperature drift characteristics of the measurement system were analyzed and compensated by the self-calibration of the reference resistance method. Based on the above-mentioned method, the minimum noise requirements were analyzed and designed for each unit of the thermometer. The temperature measurement performance of the thermometer was tested by an equivalent temperature measurement experiment with a precision resistance box and a temperature comparison experiment with platinum resistance (PT1000). The equivalent experimental results showed that the resolution of the thermometer was 0.3 mK at an ambient temperature of 20 °C and the maximum deviation of the measurement error was less than 1 mK in a large working range of 10–40 °C. The comparison experiment using a Fluke thermometer 1594A as the reference instrument showed that the standard deviation of temperature measurement was within 0.8 mK in the range of 17–23 °C.