Satellite-borne radiation calibration method and device

Abstract

The invention provides a satellite-borne radiation calibration method and device. The method comprises the steps: collecting a light beam emitted by the sun in orbit through a thin film light collector, focusing the light beam to different positions in a space in a spectral band manner, and then dividing the light beam into two paths through an optical fiber bundle, and clamping and positioning the two paths to an optical fiber positioning and switching mechanism; and switching absolute / relative radiometric calibration channels and modes through an optical fiber positioning and switching mechanism, and obtaining optical load absolute and relative calibration coefficients according to solar brightness corresponding to an injection ground calibration coefficient and an orbit parameter. The on-orbit radiometric calibration technology and device scheme provided by the invention not only have application potential in the technical field of micro optical remote sensing satellites, but also can be applied to on-orbit radiometric calibration of traditional middle and large-sized optical remote sensing satellites such as coastal zone observation imaging spectrometers, ocean observation satellites, agriculture and forestry general survey hyperspectral imagers and the like; and the accuracy of long-term on-orbit radiometric calibration data of the optical load is further improved, and the calibration flexibility is increased.

Description

technical field [0001] The invention relates to the technical field of space optics and radiation calibration, in particular to a spaceborne radiation calibration method and a device thereof. Background technique [0002] 1. Technical advantages of tiny optical satellites [0003] With the development of technology, observation tasks that originally required several tons or even dozens of tons of large satellites to complete can now be realized through a constellation of several, dozens or even dozens of tiny optical satellites. This has become the future One of the important development trends in aerospace applications and optical remote sensing. Compared with large-scale optical remote sensing satellites, the advantages of micro-satellites and their constellation systems are mainly reflected in the following aspects: first, the development cycle is very short, the launch is simple and fast, and the launch cost is low, which can meet the needs of rapid response; second, th...

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Problems solved by technology

Moreover, in order to meet the requirements of micro-satellites, more stringent restrictions are put on the weight and power consumption of the calibration device

[0007] 3. Limitations of Existing Spaceborne Radiation Calibration Technology

Its limitations are: (1) The optical path can only be cut from a certain part in the middle of the sensor, and the full optical path cannot be calibrated

(2) Place the diffuser plate at the forefront of the entire optical path. Although the expandable and retractable mechanical structure can solve the problem of calibration of the entire optical path, the weight and power consumption of the switching mechanism are too large, and it is difficult to meet the small Requirements for boundary conditions of satellite optical payloads on on-board calibration devices

However, traditional diffusers are made of Lambertian chemical materials, which are prone to decomposition under strong ultraviolet radiation in outer space

The above factors will cause changes in reflectivity, resulting in radiation calibration errors, and this error cannot be eliminated by the radiation source calibration method itself

(4) At present, the international community has begun to initially discuss the use of detector-based on-satellite calibration methods, which draw on the advantages of retractable diffusers that can calibrate all optical paths, and use sunlight as the radiation source, but do not use them as absolute Standard, the absolute standard is provided by the on-board standard radiance meter. Although this on-board calibration method solves the problem of changes in the reflectivity of the diffuser plate, it still introduces high power consumption of the radiometer and difficulties in ensuring long-term stability on-orbit. aspects of the problem

The existing scheme has the problem of high mass and power consumption of the calibration device, which is difficult to meet the application requirements of the micro-satellite for the light weight and low power consumption of the on-board calibration device.

In addition, the long-term stability of the radiation transmission of the above-mentioned calibration device is not easy to guarantee after being irradiated by cosmic rays for a long time.

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