Research On On-orbit Relative Radiometric Calibration Without Uniform Calibration Sites For Spaceborne Optical Remote Sensors

In recent years,the diversified development trend of optical remote sensing satellites has become more obvious.Many new remote sensing satellites have emerged to provide diversified data products for remote sensing applications,such as agile satellites,video satellites,and the night-time remote sensing satellites.The high-precision relative radiometric calibration of optical remote sensing satellite sensors is a prerequisite for ensuring the acquisition of high-quality observation products of various types of remote sensing satellites.The on-orbit response state of the sensor changes with time due to the influence of the factors such as the vibration of the launch,the change of the space environment,and the attenuation of the sensor itself.Therefore,the high-frequency,high-precision on-orbit radiometric calibration method of the satellite sensors is required to ensure the good application effect of data products.However,the conventional on-orbit relative radiometric calibration method of optical remote sensing satellite sensors relies heavily on the uniform calibration sites of the earth surface or the accumulation of remote sensing image samples.It is difficult to achieve on-orbit relative radiometric calibration of satellite sensors with high-frequency,high-precision and full dynamic range in the whole life cycle of remote sensing satellites,and can not meet the application requirements of remote sensing data products of the linear array push-broom sensor,plane array sensor of optical video satellites,and new night-time array sensors.Therefore,the research on the relative radiometric calibration of highfrequency,high-precision,wide or full dynamic range that does not rely on the uniform calibration sites and the accumulation of remote sensing image samples is carried out,and the on-orbit relative radiometric calibration process of sensors is optimized.It can not only break through the limitations of conventional on-orbit relative radiometric calibration methods,but also further improve the calibration method system of optical sensors,and it has important practical significance for improving the product radiometric quality of active and subsequent domestic satellites.In this paper,aiming at the image radiometric quality guarantee for the whole life cycle of optical remote sensing satellite sensors,the high frequency,high precision,wide or full dynamic range on-orbit relative radiometric calibration method of optical satellite sensors is mainly studied.Based on the analysis and summary of the existing on-orbit relative radiometric calibration methods at home and abroad,the key problems of high frequency,high precision,wide or full dynamic range calibration for linear array pushbroom sensor,optical video plane array sensor and new night-time array sensor are identified.The following studies were carried out.1)Research on the basis of relative radiometric calibration of optical remote sensing satellite sensorsThe transmission link from satellite incident light to the digital number(DN)recorded by satellite sensor are sorted out.The imaging radiometric error source of the optical remote sensing satellite sensors is analyzed,and the radiometric error transfer model of the optical remote sensing satellite is constructed,which reveals the root causes of the response inconsistency,linear response model and non-linear response of the detectors of optical remote sensing satellite sensors at different incident radiances.It is the theoretical basis for establishing the correlation between the DN value and the corresponding incident radiance.It is also the theoretical foundation for the radiometric calibration of optical remote sensing satellite sensors.Studying and analyzing the radiometric calibration model of optical remote sensing satellite sensors and the radiometric error of imaging link of optical remote sensing satellite sensors,and the influence of various errors on the image of the sensor is summarized.The existing relative radiometric calibration accuracy evaluation methods are summarized,and the meanings and application scenarios of each evaluation method are analyzed.2)Research on the on-orbit relative radiometric calibration method without uniform calibration sites for linear push-broom optical satellitesAiming at the problem that the conventional on-orbit relative radiometric calibration methods are difficult to achieve the high-frequency calibration for linear array pushbroom optical remote sensing satellite sensors and the inability to calibrate the full dynamic range of sensors,the on-orbit relative radiometric method without uniform calibration sites based on satellite agility is proposed.The calibration method,based on the satellite agile imaging capability and the characteristics of the independent of the uniform sites of the earth surface,provides a high-precision radiometric calibration datum covering the whole dynamic range of the sensor.And the high-frequency,highprecision and full dynamic range of the on-orbit relative radiometric calibration of linear array push-broom sensor is realized.The calibration data regularization processing is the key step of calibration datum extraction.For the problem of overregularization in calibration data processing,an adaptive regularization method based on dip angle detection and the regularization method with geometric distortion are proposed to extract the high-precision relative radiometric calibration datum.In order to calibrate the response difference among the CCDs in multi-CCD mosaic mode of optical remote sensing satellite sensors,a phase-dependent CCD brightness difference correction method and CCD response difference calibration method based on sample statistics are proposed to realize the correction and calibration of CCD response difference.3)Research on the on-orbit relative radiometric calibration method without uniform calibration sites based on multi-frame sequences of plane array sensor of optical video satellitesBased on the imaging characteristics of optical video satellites and the relative radiometric calibration method research status,the relative radiometric calibration without uniform calibration sites based on arbitrary video frame sequence data is proposed to achieve high-frequency,high-precision and wide dynamic on-orbit relative calibration of video satellites.The high-precision calibration datum extraction is the key step of relative calibration without uniform calibration sites,and the accurate registration of video multi-frame sequence data is the premise of calibration datum extraction.For the plane array sensor of video satellites,this paper proposes a reconstruction method based on video multi-frame data and a reconstruction method with geometric distortion to extract the calibration datum.In view of the influence of on-board data compression algorithms on the sensor response model,this paper proposes an on-orbit relative calibration processes for video satellites that isolate the effects of the on-board data compression algorithms on the sensor response model.The response relationship of each detectors of plane array sensors is preserved,and influence of the on-board data compression on the sensor response model is isolated.4)Research on the on-orbit relative radiometric calibration method without night-time uniform light source for night-time satellite sensorsAiming at the problem of night-time satellite sensors does not have a large area uniform calibration light source at night,this paper proposes an on-orbit relative radiometric calibration method based on radiometric datum conversion.A day-night radiometric datum conversion model of night-time satellite sensor is constructed.The highprecision on-orbit relative calibration of night-time sensor is realized,which does not depend on a large area uniformly calibrated light source on the night,and successfully applied to the LJ1-01.