圆周均匀多相调制相关辐射计及其灵敏度分析

A correlation radiometer structure with uniform multiphase modulation around the circumference is proposed in order to address the issue of decreased measurement accuracy caused by the operational amplifier’s offset drift and gain fluctuation in correlation radiometers. The measurement result is processed using the least square fitting method, which removes the influence of the operational amplifier’s offset drift on the measurement deviation. Based on the structure of the correlation radiometer and the noise statistical model, the expression of the temperature sensitivity of the uniform circular multiphase modulation correlation radiometer is computed, and the relationship between the system sensitivity and phase modulation order, gain fluctuation and phase shift error is analyzed. The analysis shows that with the increase of the modulation order, the influence of gain fluctuation and phase modulation error on the sensitivity becomes smaller, and the sensitivity of the uniform circular multiphase modulation correlation radiometer tends to the sensitivity of the ideal correlation radiometer.