GF-6/PMS time-series absolute radiometric calibration method based on Dunhuang radiometric site

In order to ensure the effectiveness of GF-6 panchromatic and multispectral sensor (GF-6/PMS) remote sensing data in precision agriculture applications, timely calibration of the load radiation performance parameters is required. We proposed an automated on-orbit radiometric calibration method for GF-6/PMS based on the Dunhuang radiometric correction field, realized the time series absolute radiometric calibration of GF-6/PMS transit Dunhuang field for 38 times from July 2019 to November 2024, with the resultant uncertainty better than 5%, and analyzed the effect of the site uniformity on the results. The load radiation performance decay model was established based on the effective calibration results, and the annual variation of the radiation calibration coefficients in each band was analyzed to be in the range of 0.16%~1.21%. In addition, the absolute mean value of the relative difference of the GF-6/PMS load radiative decay models in all bands except panchromatic bands in the validation of Dunhuang, Railroad Valley, and La Crau site with Sentinel-2/MSI as the reference was in the range of 2.34%~4.12%, which could indicate that the validity of the automated GF-6/PMS on-orbit calibration method is not affected by the validity of the results in this paper. This demonstrates the validity of the automated on-orbit calibration method of GF-6/PMS and provides data support for the application of GF-6/PMS remote sensing products.