High-precision dual-channel temperature measuring circuit for spacecraft ontrack leakage detection

Abstract

The invention discloses a dual-channel temperature measuring circuit which can be embedded into a spacecraft ontrack leakage detection instrument to conduct temperature compensation on the detection result. The high-precision dual-channel temperature measuring circuit comprises a four-wire thermistor, micro current constant current sources, high-precision standard resistors, a 24-bit AD sampling chip, a DSP core processor, a liquid crystal display and the like. The DSP core processor is electrically connected with a dot matrix liquid crystal display screen and is symmetrically and electrically connected with two paths of temperature measuring circuits. Each temperature measuring circuit comprises one micro current constant current source, one high-precision standard resistor, a four-wire thermistor sensor with a path of shielding ground wire and a 24-bit AD sampling component. The constant current sources supply power to the high-precision standard resistors and the four-wire thermistor sensors, wherein the high-precision standard resistors and the four-wire thermistor sensors are connected in series. The partial pressure ratios of the high-precision standard resistors and the thermistor sensors are measured through the sampling components, the processor is electrically connected with the constant current courses and the sampling components and conducts data processing by the adoption of the relation between the thermistor value and the temperature and a logarithmic fitting method to obtain the temperature, and high-precision dual-channel temperature measuring is achieved.

Description

technical field [0001] The invention belongs to the technical field of temperature measurement. Specifically, the invention relates to a high-precision dual-channel temperature measurement circuit used for temperature compensation of pressure during the on-orbit leak detection process of a spacecraft. Background technique [0002] At present, the on-orbit detection technology scheme of the total leakage rate of spacecraft cabins in my country adopts the pressure change on-orbit leak detection method, and the temperature becomes the main factor affecting the accuracy of the leak detection method. The accuracy directly affects the accuracy of its leak detection structure; and the mature high-precision temperature measurement equipment used in the leak detection process of spacecraft assembly is a stand-alone device, and all of them are foreign products, which cannot be embedded and compatible with on-orbit leak detection instruments. However, the accuracy of domestically develop...

AI Technical Summary

Problems solved by technology

Among them, the temperature acquisition circuit includes a reference resistor 1, a proportional arm resistor 2, a temperature sensor 3, and a proportional arm resistor 4. Since this circuit has nonlinearity in hardware signal acquisition, the temperature measurement must be reduced or eliminated in order to achieve high-precision temperature measurement. The nonlinearity of the circuit, self-heating and contact heat such as the resistance of the bridge arm will affect the temperature measurement accuracy, and it is difficult to meet the accuracy requirements

Images