A High-dynamic-range infrared (IR) radiometer is essential for calibrating a wide-temperature-range IR radiation source. However, a low-temperature radiation source has very weak IR radiation which is easily submerged in noise. In this paper, a chaos detection method based on Diffing-Holmes oscillator (DHO) was adopted to enhance the ability of the IR radiometer for measuring weak IR radiation. The power measurement range of the radiometer was 2.9 × 10⁻⁹–5.9 × 10⁻² W. The minimum SNR that was detected by the radiometer was as low as –22.46 dB. The noise during the measurement including the mismatch noise, the stray noise, and the detector noise were analyzed. The radiometer is calibrated by measuring a radiation source with adjustable temperature and aperture. The results show that the responsivity of the radiometer is 8.61257 × 10⁴ V/W. The combined standard uncertainty of the radiometer is less than 1.66%. The IR radiometer introduced in this paper is capable of calibrating the IR radiation source of ultralow temperature, and has been applied in the ground test of a space-borne IR detection system.

高动态范围红外（IR）辐射计对于校准宽温度范围的IR辐射源至关重要。但是，低温辐射源的红外辐射很弱，很容易淹没在噪声中。本文采用基于Diffing-Holmes振荡器（DHO）的混沌检测方法来增强IR辐射计测量弱IR辐射的能力。辐射计的功率测量范围为2.9×10 ^-9 –5.9×10 ^-2W.辐射计检测到的最小SNR低至–22.46 dB。分析了测量期间的噪声，包括失配噪声，杂散噪声和检测器噪声。辐射计通过测量温度和孔径可调的辐射源进行校准。结果表明，辐射计的响应度为8.61257×10 ⁴ V / W。辐射计的组合标准不确定度小于1.66％。本文介绍的红外辐射计能够校准超低温的红外辐射源，已应用于星载红外探测系统的地面测试中。