Miniature fixed-point blackbodies (MFPBs) can realize the on-orbit multipoint temperature calibration through the known characteristic temperature. This ability is important for improving the precision and life span of earth observation systems. For acquisition of characteristic temperature, numerical simulation has lower cost and test condition requirements. However, ordinary numerical models can’t meet the accuracy requirements of MFPB. The purpose of this paper is established an accurate numerical model for characteristic temperature acquisition of miniature fixed-point blackbodies. A novel thermal resistance equivalent corrected method (TRECM) is proposed in accordance with the difference between the numerical model and actual experiment. The equivalent correction of the total thermal resistance between two temperature points is achieved by correcting a certain term of thermal resistance in the heat flow transfer path. The TRECM can effectively replace the detailed structure, complex surface radiation and unknown parameters. Characteristic temperatures of blackbody are obtained during Ga, Ga-In, and H₂O phase transitions at different heating powers by using proposed model. Meanwhile, an experimental system is established to validate the model. The results showed that the average model error of characteristic temperature between the calculated results and the experimental results decreased from 77.2 mK to 6.2 mK by the TRECM.

微型定点黑体（MFPB）可以通过已知的特征温度来实现在轨多点温度校准。此功能对于提高地球观测系统的精度和使用寿命很重要。为了获得特征温度，数值模拟具有较低的成本和测试条件要求。但是，普通的数值模型不能满足MFPB的精度要求。本文的目的是为微型定点黑体的特征温度采集建立一个精确的数值模型。针对数值模型与实际实验之间的差异，提出了一种新的热阻等效校正方法（TRECM）。对两个温度点之间的总热阻进行等效校正是通过校正热流传递路径中的一定热阻项来实现的。TRECM可以有效替代详细的结构，复杂的表面辐射和未知参数。在Ga，Ga-In和H期间获得黑体的特征温度通过使用所提出的模型，在不同的加热功率下存在₂ O相转变。同时，建立了实验系统对模型进行验证。结果表明，TRECM将计算结果与实验结果之间特征温度的平均模型误差从77.2 mK降低至6.2 mK。