Transfer radiometer for power and radiance calibration

Abstract

The invention relates to the technical field of radiation calibration, in particular to a transmission radiometer for power and radiance calibration. The transmission radiometer comprises a diaphragm cylinder, an integrating sphere and a film-coated detector. The diaphragm cylinder comprises a field diaphragm, a stray light eliminating diaphragm and an aperture diaphragm, and the stray light eliminating diaphragm is arranged between the field diaphragm and the aperture diaphragm; the integrating sphere comprises a light inlet and a light outlet, the diaphragm cylinder is located at the light inlet, the coating film detector is located at the light outlet, and a window of the coating film detector is coated with a narrow-band filtering film layer. According to the traditional design method of replacing an optical filter combined detector with the transmission radiometer, the problem that an optical filter is sensitive to the angle of incident light is solved, and the strength of received signals can be greatly improved; and measurement signals of a plurality of channels can be read at the same time, so that the measurement time is obviously shortened.

Description

technical field [0001] The invention relates to the technical field of radiation calibration, in particular to a transfer radiometer used for power and radiance calibration. Background technique [0002] Remote sensing technology is the most important means for people to obtain information on the earth's environment. After decades of development, space remote sensing technology has become a science and technology closely related to people's lives. Very important application value. In recent years, remote sensing technology has been widely used in people's daily life. People have put forward higher and higher requirements for the reliability, accuracy and stability of remote sensing data. The calibration is of great significance. Accurate calibration of remote sensing instruments requires a high-precision primary reference as well as a short transfer link. At present, radiation measurement standards are mainly divided into two categories: one is the radiation measurement st...

AI Technical Summary

Problems solved by technology

[0005] The existing integrating sphere transfer radiometer mainly has the following disadvantages: (1) When the transfer radiometer is combined with a low temperature radiometer and a diffuse reflector to calibrate remote sensing instruments such as imaging spectrometers, the output signal of the diffuse reflector is very weak, and the transfer radiation needs to be realized. Measurement of Weak Signals

The filter is placed behind the exit of the integrating sphere. The outgoing light at the exit of the integrating sphere has a relatively large opening angle relative to the filter. The filter is sensitive to the angle of the incident light. The incident angle is greater than 5°, resulting in a larger center wavelength of the filter. Drift and transmittance drop, especially when measuring laser, the filter transmittance drops seriously, which leads to further signal attenuation and is not conducive to the measurement of weak signals; (2) the integrating sphere transfer radiometer realizes different channel measurements by rotating the filter, The transmittance at different positions of the filter is inconsistent, and the rotation deviation of the filter wheel causes differences in the positioning position of the filter each time, which introduces unnecessary measurement errors and prolongs the measurement time; (3) Integrating sphere transfer radiometer photoelectric measurement module It is composed of the same detector as the filter radiometer, and the power calibration of the filter radiometer is realized by the photoelectric measurement module. This method makes the structure of the transfer radiometer more complicated, prolongs the calibration link of the transfer radiometer, and reduces its Calibration accuracy; (4) The integrating sphere transfer radiometer realizes power and radiance conversion through two precise apertures, but the dual aperture system has limited ability to suppress stray light and is greatly affected by surrounding stray light

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