In order to meet the needs of high-precision monitoring of surface temperature remote sensing in environmental protection, land, agriculture, meteorology, disaster reduction and other industries of our country, the spatial resolution of our country’s long-wave infrared optical remote sensors has been increased from kilometer scale to ten-meter scale in recent years. The demand for quantitative applications is also increasing gradually. High-precision radiation calibration is the key to ensuring the quantitative application of infrared data. The detector of long wave infrared camera is limited by the chip material, chip preparation process, readout circuit design and production capacity and other reasons. Although the long wave infrared detector is constantly improving and developing, there are still some problems in varying degrees, such as large dark current, non-uniform response, low response and low temperature response, which directly affect the performance and radiometric calibration accuracy of long wave infrared camera.This article analyzes the factors that affect the accuracy of radiation calibration through the entire link. Combining with the specific development process of a certain model task, this article analyzes the optimization methods of the main influencing factors, including the optimization of the on-board calibration scheme, the improvement of temperature controlling accuracy and calibrating accuracy of the on-board blackbody calibration, the improvement of the performance of the long-wave detector and the improvement of the temperature controlling accuracy of the long-wave detector on the focal plane to improve the performance and output stability of the camera. The radiation calibration accuracy and the response state of system calibration has been verified through the vacuum radiation calibration test of this model. The test results show that the response slope of the radiometric calibration equation of the long wave infrared camera is effectively improved (from better than 45 of GF-5 01 satellite to better than 125 of GF-5 02 satellite), the output stability of the camera system is improved (DN value fluctuation is reduced from 20-30DN of GF-5 01 satellite to 1-2 DN of GF-5 02 satellite), and the accuracy of radiometric calibration is improved (from 1 K@300 K of GF-5 01 satellite decreased to 0.8 K@300 K of GF-5 01 satellite）.It reaches a high level among the same type of domestic long-wave infrared space optical remote sensors with a spatial resolution of less than 100 m. The performance improvement method of long-wave infrared space optical remote sensor introduced in this article can provide reference for the development and radiation calibration of similar remote sensors in the future. The calibration test verification results provided in this article can also provide references for the in-orbit applications of similar infrared satellites.

optical remote sensing;space optical remote sensor;long-wave infrared;vacuum radiation calibration test;absolute radiation calibration accuracy