Research In Optoelectronic Observation Technologies For Space Objects

Space objects include on-orbit spacecraft and space debris. Space debrisseverely threatens the security of on-orbit spacecraft, which idrectly changes thesurface properties of the spacecraft in their collisions, and brings seriousness andgreat harm to the normal operation of on-orbit spacecraft, resulting in failure of thespacecraft system. Optical observation for space objects plays more and moreimportant roles in space objects surveillance. In order to improve performance ofour national space objects surveillance, an in-depth study of space objectssurveillance technology will have important practical significance and applicationvalue.The survey techniques start with measurement principle, detection andidentification, precise orientation and photometry of space objects, andphotooelectric telescope, discussions are made in methods of improvementsdetecting efficiency for space objects surveillance devices and higher orientationprecision for space objects.Firstly, this paper offers some insights into photooelectric telescope system ofspace objects, which include complex optical systems, telescope mount andorientation methods, and compare the advantage and disadvantage of astronomicalorientation and shafting orientation. To solve the shortage of spherical harmonicsfunction model and basic parameters model, a new algorithm for real-timecorrection of telescopes’ pointing error is proposed, whose pointing precision of telescope is2.82″at L axle and2.85″at B axle. This algorithm has good real-timeand high precision, which can be widely applied to science and engineering field.Secondly, this paper offers some insights into the ability of detection for spaceobjects, which include the detectable stellar magnitude limits， the atmosphericextinction coefficient and the size of detectable space objects, and summarizesseveral ways to improve detecting efficiency of photooelectric telescope. Then thispaper offers some insights into astronomical digital image processing technique,which include image preprocessing, image enhancement technology, imagerestoration technology and mathematic morphology.Meanwhile, based on analysisof space objects’ motion characteristics within the visible field of the CCD chip, thefast recognition algorithm is presented and realized. Experimental results indicatethat the average processing time of fast recognition for space objects is less than10ms, which can satisfy the requirements of space objects’ surveillance, such ashigh real-time, high precision, good stability and reliability.Thirdly, based on the introduction of astronomical orientation’ fundamentals,real-time astronomical orientation of space objects is realized in the usage ofTycho-2and triangle matching algorithm. Experimental results indicate thatthe average processing time of real-time astronomical orientation for space objects isless than25ms, and the precision of real-time astronomical orientation is less than4,which can satisfy the requirements of space objects’ surveillance, such as highreal-time, high precision, good stability and reliability. In addition, to overcome loworientation precision of faint space objects, the high precision orientation algorithmof faint space objects is presented using the improved traditional astronomicalorientation method, which continuously captures3frames (the time exposure of thefirst and third frames is short, meanwhile one of the second frame is long),calculates negative processing model of the first and third frames and leads to highaccuracy negative processing model of the second frame, and gets the high accuracypositioning result of the second frame. We finally realize that high accuracy positioning of faint space objects in deep space, which can further improve thedetection ability and positioning accuracy of the photoelectric telescope system.At last, photometry is one of the important missions of space objects. There isno filter system equipped in the space objects telescope, which can’t measureinformation of star magnitude for space objects. A simple and convenient algorithmfor measuring information of star magnitude is presented, which can provideinformation of star magnitude with certain range of the accuracy requirement, andan effective way for photometry of space objects.