Calibration Of GF1 Wide Multispectral Time Series

Radiation calibration of sensors is a prerequisite for realizing the quantification of remote sensing satellite data.The accuracy of calibration directly determines the quality of quantitative remote sensing products.As China's first high-resolution Earth observation system satellite,the GF1 satellite data has played an important role in many fields such as resource surveys,natural disaster assessments,and environmental monitoring.In order to improve the data quality and quantitative application level of GF1 satellite multispectral camera in China,long-term sequence calibration of GF1 satellite multispectral camera must be carried out.The research object of this paper is GF1 wide-spectrum multi-spectral camera.The Dunhuang radiation correction field is used as the research area to carry out radiation calibration research.The specific research contents are as follows:(1)There are certain limitations in site calibration: a large amount of on-site measurement data is required,which is time-consuming and labor-intensive,and the number of calibrations is limited,making it difficult to monitor sensor performance changes in time.This paper uses a high-frequency cross-radiation calibration method for time series calibration of remote sensors.Cross calibration is somewhat high in frequency and requires less cost.It can be used to scale historical images to achieve time series calibration of satellites.By briefly introducing the calibration area conditions and the overview of the Dunhuang radiation correction field,the spectral matching,geometric correction and image registration in the pre-processing are introduced and analyzed in detail.(2)For the high-band one-spectrum multi-spectral visible light and near-infrared four bands,this paper uses MODIS and LandSat8 data as the reference image,and uses Dunhuang radiation correction field as the test area for cross-radiation calibration.The cross-calibration coefficients are obtained by calculation,and the error and uncertainty of the calibration results are analyzed.On this basis,using the high score number one to cross-calibrate the "High Score 4"(GF4)camera,and verify the accuracy of the results,it is concluded that the GF1 satellite can be used as a cross between the autonomous satellite remote sensors in China.Reference satellite for calibration studies.(3)For the GF1 satellite,the launch time is relatively long,and there is only one site calibration every year.In this paper,time series sequencing of GF1 satellite wide-spectrum multi-spectral(WFV)cameras is carried out,and the calibration coefficients for 2013-2017 are obtained.The results show that the calibration results of GF1/WFV4 show a significant trend,the bands 2,3,4 are the downward trend,the decline range is about 5%,and the band 1 is the rising trend,which is up 4.18%.WFV3 showed a downward trend,WFV1 and WFV2 had a relatively obvious upward trend;WFV4 had the most stable radiation performance,and all bands had less than 5% radiation variation.