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ФУНКЦІОНУВАННЯ ТА РОЗВИТОК УКРАЇНСЬКОЇ МЕРЕЖІ ОПТИЧНИХ СТАНЦІЙ. О.В. Шульга , Є.Б. Вовчик, М.І. Кошкін , С.П. Кравчук, В.П. Єпішев. Ukraine network of optical stations (UMOS). Objectives of UMOS.
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ФУНКЦІОНУВАННЯ ТА РОЗВИТОК УКРАЇНСЬКОЇ МЕРЕЖІ ОПТИЧНИХ СТАНЦІЙ О.В. Шульга, Є.Б. Вовчик, М.І. Кошкін, С.П. Кравчук, В.П. Єпішев
Objectives of UMOS • The main goal of UMOS shall be to unite scientific and technical means and to conduct regular optical (positional and/or non-positional) observations of the objects in Earth orbit (OEO). • UMOS shall solve strategic problems of near-Earth space research to study the properties of motion of the selected OEO by developing theory of their motion and by improving models and algorithms of data processing. UMOS shall solve tactical problems of launch support for space vehicles made in Ukraine and other countries. • UMOS shall look for ways to attract investment in the development of applied and fundamental scientific research through the promotion of the results to the international scientific community and interested organizations.
Combined method of observation NEAand stars on differentimages(combined method) 2005 GQ21 App. motion= 9.69 ˝/ m, Exposure = 1.5 m Pixel size = 0.83"
Method of frame accumulationwith shift • Method consists in the summing of video frame with the shift which correspond to a offset of the observed object in the field of TV CCD camera. • Synchronous accumulation allows to obtain a point-like images of uniformly moving objects with exposure time limited only by the time passage of the object through the field. • The reference stars accumulation held parallel with accumulation of object image.
Time delay and integration mode with rotation Stare frame Tdi frame
Ephemeris support Orbital elements calculation using observational data obtained on the one orbit pass. Algorithm: 1.Making correction to positions of satellites forannual and daily aberrations, with using of Sun coordinates from DE/LE 405. 2. Calculation of initial orbit elements and state vector of satellites by 3 positions using classical Laplace method. 3.Orbit improvement using the method of differential correction based on the analytical model of satellites motion (two-body problem) by all position of satellite, the second zonal harmonic of Earth and luni-solar perturbations be taken into consideration in the model 4. Exception of position with high random errors by criterion 3*ε. 5. Final orbit improvement using the method of differential correction based on numerical model of motion, calculation of osculating orbital elements and state vectors on mean moment of observation.
Ephemeris support Orbital elements calculation using of observation on several orbit passes obtained on one telescope Orbital elements which calculated from observation on several orbit pass are more reliable than on one orbit pass and using for formation of orbit catalogue. Algorithm: 1.Selection of longest reference orbit pass. 2. The orbital elements calculation using reference circuit in time of one- orbit pass calculation taken as initial. 3. The trust checking of orbital elements is performed by comparing inclination, eccentricity and period of rotation with catalogue NORAD. 4. Orbit pass closest in time to the reference is included to calculation. 5. The state vector improvement using the method of differential correction based on the numerical model. 6. The next orbit pass is included to calculation. 7. The osculating orbital elements and state vectors to average time are calculated.
Control of the observation accuracy Control of the observation accuracy is performed by comparing the ILRS ephemeris (http://ilrs.gsfc.nasa.gov/) with position obtained from optical observation of UMOS. Comparison algorithm: • Search and loading the files of ILRS ephemeris for each satellite on the date of observation. • Conversion of the three-dimensional coordinates from ITRS system to ICRS on J2000.0 epoch. 3. Making correction to observation for annual and daily aberrations. 4. Making correction to observation for planetary aberration. 5. Calculation of rectangular coordinates of ephemeris on moment of time of observation using of Lagrange interpolation by 12 points. 6. Conversion of the rectangular coordinates to angular topocentric. 7. Calculation of (O-C) between observation and calculation coordinates of satellites.
Observation results Statistic of catalog filling by orbit type Statistic of catalog filling by years
Observation accuracy LEO satellite Errors of ephemerides (gray dots — along orbit (dL), black dots — across orbit (dH), straight line — dL = −44.11t − 14.44 for low earth orbit satellite 16098 (1490 km), orbit calculated using two set of observation (1.075 orbit pass) GEO satellite Errors of ephemerides (gray dots — along orbit (dL), black dots — across orbit (dH), straight line — dL =−1.642t − 15.17 for geosynchronous satellite17125 (35800 km), orbit calculated using two set of observation(2.53 orbit pass)
Photometry Sich2 During a period of active existence After period of active existence During a period of active existence Envisat After crash
Synchronous photometric observations Photometry of satellite 16908 Adjisai 03 november 2014 atOdessa and Lviv stations Photometry of satellite 16908 Adjisai27october 2014 atOdessa and Uzhgorod stations
