Study On The Key Technologies For High-accuracy And All-time Star Sensor

Star sensor is a high accuracy sensitive instrument for attitudedetermination.Star sensor uses stars as the frame of reference and provides accuratespatial orientation and benchmark.Star sensor has the advantages of high accuracy,anti-jamming, and independent navigation not depending on other systems.Traditional star sensor is generally used as navigation equipment for satellites,spacecrafts, rockets and so on. With the development of the navigationtechnology,the accuracy of star sensor is improving,the application range of starsensor is also gradually expanding. In addition to the usage in the space platform,some foreign institutions try to use the star sensor technology in the platform nearthe ground,such as the large aircraft, the near space aircraft and warship.The firstgeneration of star senor is characterized by a small field of view and highmagnitude.The second generation of star senor is characterized by autonomousnavigation.After the development of the two generations,the star sensor technologyhas two new development trends in recent years:one is high-accuracy,the other isall-time and near-ground application.In view of the new development trends of the star sensor technology, thisdissertation presents the solution of high-accuracy and all-time star sensor.Compared with the traditional star sensor, it is characterized by high accuracy, shortintegration time, near the ground, and all-time work. The main contents of this paper is to research the way to improve the measurement accuracy of star sensor, thesecond is to carry out research on daytime star detection in the atmosphere.This dissertation analyzes the calculation method and the relationship of the keyparameters such as field of view, focal length, detection sensitivity, measuringaccuracy and data update rate.The key technologies of high-accuracy and all-timestar sensor are discussed, including spectral filtering, the EMCCD imaging and noisesuppression,and target detection under complex sky background.This dissertation discusses EMCCD imaging system circuit design methods,analyzes the application of a new type of EMCCD device in star sensor, proposeseffective methods of reducing EMCCD image noise, and verifies the rationality ofthe design by the experimental data analysis.In order to resolve preprocessing problem of star sensor images taken atdifferent times with different backgrounds,the dissertation studies the preprocessingand extraction methods of star-target under complex sky background, proposesimage preprocessing tactics and background prediction method of multi-scaleneighborhood saliency analysis base on complexity.On the basis of the key technologies research,the engineering prototype ofhigh-accuracy and all-time star sensor has been developed, and related experimentsare carried out. The composition of experimental system and calibration ofhigh-accuracy star sensor are discussed.Some experiments which are carried outincluding verification of single star measurement accuracy,magnitudecalibration,all-time star detection,and the experimental data are analyzed. The endof the dissertation is preliminary study on the development prospects of thehigh-accuracy and all-time star sensor, the technical and engineering problems whichstill need to be solved.