CN-121995406-A - Point light source-based on-orbit satellite response calculation method

CN121995406ACN 121995406 ACN121995406 ACN 121995406ACN-121995406-A

Abstract

The invention relates to the technical field of absolute response calculation of an in-orbit optical remote sensing satellite, in particular to an in-orbit satellite response calculation method based on a point light source, which comprises the steps of calculating the entrance pupil radiation brightness and response value of a remote sensing camera; the method comprises the steps of calculating a spectral response function and a spectral response bandwidth of a remote sensing camera, calculating equivalent entrance pupil radiation brightness through wavelength infinitesimal, carrying out least square fitting calculation on the equivalent entrance pupil radiation brightness and a response value to obtain an absolute radiation calibration coefficient, calculating absolute radiation brightness under an equivalent extended light source, calculating the absolute radiation brightness of the upper atmosphere boundary through atmospheric transmittance and the absolute radiation brightness under the equivalent extended light source, calculating the equivalent radiation brightness through the spectral response bandwidth, and calculating the output response value of the remote sensing camera according to the equivalent spectral radiation brightness. The invention utilizes the principle of point source target radiation transmission and combines the basic principle of optical remote sensing camera radiation calibration to realize the in-orbit satellite response calculation based on a point source.

Inventors

GAO ENYU
WANG QIANG
CHEN ZHE
WANG CHUNPENG
ZOU YANLI

Assignees

长春国宇光学科技有限公司

Dates

Publication Date: 20260508
Application Date: 20251226

Claims (10)

1. An in-orbit satellite response calculating method based on a point light source is characterized by comprising the following steps: s1, performing radiometric calibration on a remote sensing camera in a laboratory, and calculating the entrance pupil radiance and response value of the remote sensing camera; S2, performing spectrum calibration on a remote sensing camera in a laboratory, and calculating a spectrum response function and a spectrum response bandwidth of the remote sensing camera; S3, calculating equivalent entrance pupil radiation brightness of the remote sensing camera through the entrance pupil radiation brightness, the spectral response function, the spectral response bandwidth and the wavelength infinitesimal; s4, performing least square fitting calculation through the equivalent entrance pupil radiation brightness and the response value to obtain an absolute radiation calibration coefficient; s5, calculating absolute radiation brightness under an equivalent extended light source through the radiation brightness of the light source, the opening area of the light source and the ground resolution of the optical remote sensing satellite; S6, calculating to obtain the absolute radiation brightness of the upper boundary of the atmosphere through the atmospheric transmittance and the absolute radiation brightness under the equivalent extended light source; S7, calculating to obtain equivalent radiation brightness through the atmospheric upper bound absolute radiation brightness and the spectral response bandwidth; And S8, calculating to obtain an on-orbit satellite response value according to the equivalent spectrum radiation brightness and the absolute radiation calibration coefficient.
2. The method for calculating the response of the on-orbit satellite based on the point light source according to claim 1, wherein in step S3, the equivalent entrance pupil radiance calculation formula is: ; Wherein L is equivalent entrance pupil radiance, L s (lambda) is entrance pupil radiance, R (lambda) is a spectral response function, [ lambda ] 1 ,λ 2 ] is a spectral response bandwidth, and dlambda is a wavelength infinitesimal.
3. The method for calculating the response of the point light source-based on-orbit satellite according to claim 1, wherein in step S4, the least squares fit calculation formula is: ; wherein L is equivalent entrance pupil radiance, And And DN is the response value of the remote sensing camera for the absolute radiation calibration coefficient.
4. The method for calculating the on-orbit satellite response based on the point light source according to claim 1, wherein in the step S5, the calculation formula of the absolute radiance under the equivalent extended light source is: ; Wherein L extention is absolute radiation brightness under the equivalent extended light source, L point is radiation brightness of the light source, S is opening area of the light source, Is the ground resolution of the optical remote sensing satellite.
5. The method for calculating the response of the on-orbit satellite based on the point light source according to claim 4, wherein in the step S5, the radiation brightness of the light source is measured by a spectral radiometer, the ground resolution of the optical remote sensing satellite is calculated by the orbit height of the on-orbit satellite, the pixel size of the sensor and the focal length of the camera, and the calculation formula is as follows: GSD=(D×H)/f; in the formula, The ground resolution of the optical remote sensing satellite is that f is the focal length of the remote sensing camera, H is the orbit height of the in-orbit satellite, and D is the sensor pixel size.
6. The method for calculating the response of the on-orbit satellite based on the point light source according to claim 1, wherein in step S6, the calculation formula of the absolute radiance of the upper atmosphere is: ; wherein L atm is the absolute radiance of the upper atmosphere boundary, For the atmospheric transmittance, L extention is equivalent to expanding the absolute radiance under the light source.
7. The method for calculating the response of the on-orbit satellite based on the point light source according to claim 1, wherein in step S7, the calculation formula of the equivalent radiance is: L 1 =L atm ×1000/(λ 2 -λ 1 ) Where L 1 is equivalent radiance, L atm is absolute radiance of the upper atmosphere, and [ lambda 1 ,λ 2 ] is spectral response bandwidth.
8. The method for calculating the response of the on-orbit satellite based on the point light source according to claim 1, wherein in step S8, the calculation formula of the response value of the remote sensing camera on the on-orbit satellite is as follows: DN 1 =(L 1 - )/ ; Where DN 1 is the remote sensing camera response value on an in-orbit satellite, L 1 is the equivalent radiance, And The coefficients are calibrated for absolute radiation.
9. The method for calculating the response of an on-orbit satellite based on a point light source according to claim 1, wherein in step S1, the remote sensing camera is radiometric calibrated by a split-sphere radiometric calibration system.
10. The method of claim 1, wherein in step S2, the remote sensing camera is spectrally scaled by a monochromator and parallel light pipe spectral scaling system.

Description

Point light source-based on-orbit satellite response calculation method Technical Field The invention belongs to the technical field of absolute response calculation of an in-orbit optical remote sensing satellite, and particularly relates to an in-orbit satellite response calculation method based on a point light source. Background With the vigorous development of commercial aerospace in China, the number of in-orbit satellites is increased, remote sensing satellites travel in space, and people hope that the space eyes can see more and more clearly for protecting the land, maritime affairs, weather and other fields on the earth on which people depend to live. The satellites are launched into space by space flight vehicles such as rockets, spacecrafts and the like, and the satellites are classified according to different sizes like natural satellites, after the satellites are launched, the ground needs to control the satellites, so that the satellites can smoothly enter the surrounding orbit of a celestial body, the calibration precision of the remote sensing satellites is improved, and the method has a decisive role in ensuring the inversion precision of satellite products. The goal of radiometric calibration is to determine the quantitative conversion of the amount of radiation at the sensor entrance pupil to the output value. When the sensor enters the orbit to start running, the optical characteristics of the sensor can be changed due to the influence of strong vibration in the transmitting process, strong radiation environment of the space and decay of the optical sensitive device. If the laboratory scale factor is used continuously, the accuracy of the remote sensing data cannot be guaranteed. Accordingly, there is a need for continuous on-track calibration using an on-track alternative calibration method to monitor and correct sensor radiation response conditions. The invention provides an in-orbit satellite response calculation method based on a point light source based on the problems that the existing in-orbit calibration method is large in workload, long in calibration period, low in solar high angle, poor in calibration effect of a reflecting mirror and even incapable of calibrating at night time. Disclosure of Invention In view of the above, the invention aims to provide an in-orbit satellite response calculation method based on a point light source, which utilizes the principle of point source target radiation transmission and combines the radiation calibration of an optical remote sensing camera to realize the response calculation of an in-orbit satellite. In order to achieve the above purpose, the technical scheme of the invention is realized as follows: an in-orbit satellite response calculating method based on a point light source comprises the following steps: s1, performing radiometric calibration on a remote sensing camera in a laboratory, and calculating the entrance pupil radiance and response value of the remote sensing camera; S2, performing spectrum calibration on the remote sensing camera in a laboratory, and calculating a spectrum response function and a spectrum response bandwidth of the remote sensing camera; s3, calculating equivalent entrance pupil radiation brightness of the remote sensing camera through entrance pupil radiation brightness, a spectral response function, a spectral response bandwidth and wavelength infinitesimal units; s4, performing least square fitting calculation through equivalent entrance pupil radiation brightness and response values to obtain an absolute radiation calibration coefficient; s5, calculating absolute radiation brightness under an equivalent extended light source through the radiation brightness of the light source, the opening area of the light source and the ground resolution of the optical remote sensing satellite; S6, calculating to obtain the absolute radiation brightness of the upper boundary of the atmosphere through the atmospheric transmittance and the absolute radiation brightness under the equivalent extended light source, S7, calculating to obtain equivalent radiation brightness through the absolute radiation brightness of the upper boundary of the atmosphere and the spectral response bandwidth; S8, calculating to obtain an on-orbit satellite response value according to the equivalent spectrum radiation brightness and the absolute radiation calibration coefficient, Further, in step S3, the calculation formula of the equivalent entrance pupil radiance is: ; Wherein L is equivalent entrance pupil radiance, L s (lambda) is entrance pupil radiance, R (lambda) is a spectral response function, [ lambda ] 1,λ2 ] is a spectral response bandwidth, and dlambda is a wavelength infinitesimal. Further, in step S4, the least squares fit calculation formula is: ; wherein L is equivalent entrance pupil radiance, AndAnd DN is the response value of the remote sensing camera for the absolute radiation calibration coefficient. Further, in step S5,