The Optical Measurement Method And Precise Orbit Determination For The Satellite

In the past20years, with the development of space science, astronomy and theobservation techniques, the astrometric observations’ precision is improved from afew percent arcsecond up to sub-milliarcsecond. The limit magnitude of theastrometric observations is extended from11mag,12mag to20mag. The band ofthe observation is developed from a single optical band to multiple bands of optical,radio, infrared, etc. The VLBI technology’s mature, the publication of theHipparcos catalogue and the widely use of the CCD techniques are the landmarksin the process of the above develpments. The Hipparcos astrometric satellite andthe Hubble Space Telescope Launched in late1980s indicated that the spaceastrometry time has come. The Gaia astrometric satellite was successfully launchedin December2013, which would bring profound impact in astrometry field. Spaceastrometry is booming. At the same time, the ground astrometry is still playing theirreplaceable role in astronomy research. By means of the improvements ofobservation equipment technology and data processing methods, the research ofground CCD optical observation has been greatly promoted. In addition, the highprecision and density space catalog guaranteed the precision of the observationspositioning.Based on the status of modern ground astrometry big data era, the AutomaticDigital CCD Images Astrometric Software (ADIAS) was developed in thisdissertation, which was applied in the processing observations data of naturalsatellites and GEO objects. And then, with the high precision observations, theresearches of improvement of Triton’s orbit and the joint orbit determinationof theGEO objects were studied. The main research work in this dissertation is asfollows:1. The Development of Automatic Digital CCD Images AstrometricSoftware (ADIAS)(1) The median filtering technology was used in the development of ADIAS.By means of setting the reasonable size of the filtering window, the cosmic rays,salt and pepper noise can be removed. In addition, this method was used togenerate a flat image for correcting the CCD images. Combined with the imageenhancement method, they could solve the difficulties whenthe flat image couldn’tobtain or miss the right time to take. Instead, this method can supply the real-time flat image for every CCD image (Limited in the research of the targets positioning).On the other hand, the preprocessing of the images ca n provide the cleaner imagesfor the later work, which would greatly improve the efficiency of imageprocessing.(2) ADIAS has been completed. This dissertation described the keytechnologies of this software, such as astrology recognition algorithm,astrology-centering algorithm, reference stars matching algorithm and so on. Inaddition, its integrated positioning results were compared with the results from theinternational common software ‘Astrometrica’. And the accuracy analysis wasgiven.2. The ground-based optical observations and orbit improvement of thenatural satellite Triton(1) The idea of employing the small diameter optical telescope on theobserving campaigns for the natural satellites was proposed, and Triton was chosenas the targets in the experiment. The observation results have been compared withthe JPL ephemeris, which fully verified the feasibility of the proposal. This articlealso noted that more small aperture optical telescopes can be implemented on theobserving of the natural satellite during the planets oppositions, which wouldlargely increase the richness of the natural satellite data;(2) Cooperated with French scholar G. Dourneau and British scholar D. Harper,more than30years home and aboard observations of the Triton were employed inthe Triton orbit improvement. During this work, the new Triton orbit wasconsidered the affect of precessional motion of the Neptune’s pole. IMCCEindexed the new ephemeris to its Web site as the new Triton ephemeris thatprovided services to the public;(3)1095Triton observations obtained during2007-2009were processed byADIAS. With the results, two orbit models of Jacobson (2009) and Zhang et al.(2014) were compared. They showed a very good fit with the observations.Moreover, with the help of Triton’s observations, the two existing models Tritonand10kinds of planets ephemeris were respectively combined as theoreticalpositions, which were compared with the observed data and the comparison resultand analysis were given in this paper.3. The joint orbit determination with the angular and rangingobservations of the GEO satellite(1) Aimed to meet the needs of determining the forecast target location in the optical angular measurement system, the visualization GEO target positionforecasting software was designed based on the TLE file;(2) By means of ADIAS, the observations of the25404satellite wereprocessed. The observations were observed during28th April to1st May,2010.For these observations, the special algorithms were designed, which was used toseparate and classify the multi-target image in the same screen;(3) The research of joint orbit determination was carried out. During theresearch, the observations obtained in28-29April,2010were used, which includedthe optical angle measurement data and ranging data. For the experiments of theorbit determination, there are many types of the combination of the two differentsystems as angle and distance station, which are such as single angle stationrespectively combined with one, two, or more than two ranging stations. Then, theaccuracy analysis of the joint orbit determination of all the types mentioned abovewas presented. The joint orbit determination with a single angle station and a singledistance station can achieve better than5meter precision, which can help makebest use of the ranging observations and offer great help to realize rapid initialorbit.