Ce-1 Microwave Sounder Ground Calibration

ChangE-1(CE-1) will be the first satellite of China flown in Moon orbit. It's radiometer operates at 3.0, 7.8, 19.35 and 37GHz in a nadir viewing mode. By now, the pre-launch experimental CE-1 Microwave Radiometer is developed. In this paper, an experiment on the ground calibration of it is carried out. First, the electrical performance of the radiometer is tested to reach the performance mark, which is the foundation of the work in this paper. Second, The linearity of its receivers of the four channels is obtained to be 0.99957,0.99991,0.99984 and 0.9999, respectively. And the sensitivity of them is obtained to be 0.30K,0.14K,0.11K and 0.17K, respectively. The linearity and the sensitivity of receivers of the four channels all satisfy the performance requirements too, so CE-1 Microwave Radiometer can be calibrated through high and low temperature points: the high temperature point is from the matching load, the low one is from the liquid nitrogen refrigerated calibration blackbody target. Meantime, to amend the influence by the transmission network, the modified hardware radiative transfer model is built up. Finally, the antenna temperature calibration equations of the four channels, which account for losses and mismatch, are derived based on the model. And the error of calibration is analyzed. The results provide a constructive reference to the development of CE-1 Microwave Radiometer for launch.