HJ-1A multispectral imagers radiometric performance in the first year

HJ-1A and HJ-1B, the first micro-satellite constellation for Environment and Disaster Monitoring of China, was successfully launched in China on September 6, 2008. The same multispectral imagers named HJ-1/CCD with four bands (R, G, B, Nir) and large swath are installed on both HJ-1A and HJ-1B. The HJ-1/CCD is the main sensor of the constellation. In this paper, data sets includes six image pairs of HJ-1A/CCD and Terra/Modis and field reflectance spectra of Dunhuang Calibration Site are acquired. Cross calibration is taken to get the calibration results of HJ-1A/CCD relative to Terra/Modis. Based on the calibration results, the radiometric performance of HJ-1A/CCD is evaluated. Taking into that the good radiometric performance of Terra/Modis, it is obvious that HJ-1A/CCD has a radiometric attenuation during its second half of the first year. The max attenuation occurred on the near infrared band is about 18%. The min attenuation occurred on the blue band is about 8%. There maybe some inevitable errors about the data sets and produced during the processing. More images should be acquired and more attention should be paid to get the true radiometric attenuation.