On-orbit Platform Jitter Effect On Image Quality Of High-Resolution Remote Sensor

During remote sensor’s on-orbit working process, vibration caused by reactionwheel assembles; solar panels and other spacecraft components can producevibration. Most of vibration with larger amplitude and lower frequency can becompensated and suppressed by attitude controllers. While vibration with smalleramplitude and higher frequency will still convey through the platform to remotesensor, result in subtle jitter and weaken attitude stability of the sensor. Due to thetiny unit pixel view angle of high resolution remote sensor, jitter will lead to imagepoint of ground scene indistinct and imaging quality declined in exposure time. Withthe development of spacecraft attitude control method, remote sensing, opticalsystem design and manufacturing level, ground resolution of remote sensorcontinuously improves. Jitter has become an important factor of high resolutionremote sensing image quality. To study the influence law of on-orbit platform jitterto image quality of high resolution remote sensing, is of great significance to theimprovement of remote sensing performance. Paper’s main works are as follows:On the basis of theoretical and experimental research on image quality reductionby platform jitter both at home and abroad, jitter within100Hz and hundreds ofμrads amplitude is determined as research object. Simulation model of remotesensing from ground targets to image is built up according to the optical chain theory. Based on the ray tracing method, imaging elements consist of platform vibrationspectrum, attitude of satellite and payload, optical system of the sensor and CCDimage sensors are modeled, thus according to given parameters, MTF calculationand simulated imaging to specified ground scene area by gaze or push-broomapproach is established.Staring imaging on Geo synchronous orbit and push-broom imaging on Sunsynchronous orbit are two kinds of typical remote sensing imaging environment.Imaging simulation for staring imaging on Geo synchronous orbit with remotesensing simulation model is carried out. On the basis of MTF degradation by5%,relationship between image quality tolerance and sinusoidal jitter frequency isdiscussed with different amplitude and frequency of sinusoidal vibration as jitterinput. Typical platform vibration spectrum consists of low-pass noise, whitebackground noise and vibration peak components are simulated. Degrade lawsbetween image quality and vibration spectrum components are analyzed. Vibrationspectrums components are sorted by degrade intensity to image quality. Componentsof influence differences to image quality due to intensity are discussed.On the basis of analysis of staring imaging on Geo synchronous orbit, Imagequality degradation law under different jitter conditions accordingly are discussed inthe condition of TDI push-broom imaging on sun synchronous orbit.Imaging hardware experimental platform is built. Subtle vibration with highfrequency and small amplitude is realized by fast steering mirror droved bypiezoelectric ceramic material. By which platform jitter is simulated. With thehardware platform, experiments involved in simulation experiments are verified, andthe validity of the simulation’s conclusions are proved.