Design of motion compensation mechanism of satellite remote sensing camera

Abstract

With the development of aerospace remote sensing technology, the ground resolution of remote sensing camera enhances continuously. Since there is relative motion between camera and ground target when taking pictures, the target image recorded in recording media is moved and blurred. In order to enhance the imaging quality and resolution of the camera, the image motion had to be compensated. In order to abate the effect of image motion to image quality of space camera and improve the resolution of the camera, the compensation method of image motion to space camera is researched. First, the reason of producing drift angle and adjustment principle are analyzed in this paper. This paper introduce the composition and transmission principle of image motion compensation mechanism. Second, the system adopts 80C31 as controller of drift angle, and adopts stepping motor for actuators, and adopts absolute photoelectric encoder as the drift Angle measuring element. Then the control mathematical model of the image motion compensation mechanism are deduced, and it achieve the closed-loop control of the drift angle position. At the last, this paper analyses the transmission precision of the mechanism. Through the experiment, we measured the actual precision of the image motion compensation mechanism, and compared with the theoretical analysis.There are two major contributions in this paper. First, the traditional image motion compensation mechanism is big volume and quality heavy. This has not fit for the development trend of space camera miniaturization and lightweight. But if reduce the volume and quality of mechanism, it will bring adverse effects for the precision and stiffness of mechanism. For this problem, This paper designed a image motion compensation that have some advantages such as small size, light weight at the same time, high precision, stiffness and so on. This image motion compensation can be applicable to the small optics cameras with high resolution. Second, the traditional mechanism control need to corrected, fitting and iterative for the control formula of mechanism. Only in this way, we can get the optimal control mathematical model. This paper has high precision of the control formula derived. It can achieve the high precision control without fitting, It also simplify the difficulty of control mathematical model establishment.This paper designed the range of adjusting of image motion compensation mechanism between -5°~ +5°. Based on choosing-5°, -4°, -3°, -2°, -1°, 0°, +1°, +2, +3°, +4°, +4° as the expectation value of the imaginary drift angle, we get ten groups of the fact data in adjusting drift angle measured. The test results show that the precision of the drift angle control system can be achieved in 1. It can meet the system requirements that the precision of the control system is less than 3 ', and it can achieve the high-precision image motion compensation.