On-board relative calibration method and numerical simulation of array optical remote sensor based on LED

Abstract

Due to the strong vibration, space irradiation and device aging of the array remote sensor, the output value of each pixel will be inconsistently attenuates, resulting in strips and even blind pixels, which will reduce the image sharpness and result in the inability to accurately identify the target. In order to realize the high-frequency and high-precision in-orbit relative calibration of large-caliber array optical remote sensors, an on-board calibration method for array optical remote sensors using LED point light source illumination is proposed. LED point light source has the advantages of small size, light weight, strong shock resistance, long life and good stability, and can be regarded as lambertian source after relative distribution correction. In addition, the linear and high-frequency response characteristics of the LED point light source are linearly calibrated for the remote sensor. Based on the characteristics of the uniform attenuation of LED point light source, the non-uniformity correction algorithm of LED point light source illumination and the relative calibration theory of remote sensor on-board are constructed. Through numerical simulation, the non-uniformity 2.7% LED point light source relative calibration system, after being corrected by the non-uniformity 1% standard uniform source, the relative calibration of the array remote sensor is performed, and the calibration accuracy is 0.49%. When the LED point light source is shifted by 1.5% from the eccentric remote sensor, the relative calibration accuracy of the remote sensor is only reduced by 0.2%. The relative calibration accuracy of the on-board optical remote sensor based on the LED point light source is mainly affected by the uniformity of the standard source used to correct the relative distribution coefficient of the LED. Therefore, the use of LED point light source for the relative calibration of the on-board optical remote sensor is not only engineering, but also provides high-frequency, high-precision on-orbit calibration, and remote sensor health checking.