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Optical Tracking System for Observations of Natural and Artificial Space Objects
  • Diana Haritonova,
  • Ansis Zarins,
  • Augusts Rubans
Diana Haritonova
University of Latvia

Corresponding Author:diana.haritonova@lu.lv

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Ansis Zarins
University of Latvia
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Augusts Rubans
University of Latvia
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Abstract

The Institute of Geodesy and Geoinformatics (GGI) of the University of Latvia (UL) is focused now on configuring of the recently designed optical tracking system and launching of a test program for positional astrometric observations. The instrument is eventually intended for both positional and laser ranging observations of near-Earth objects. The tracking system has Alt-Alt mount and optical scheme with three optical channels: transmitter equipped with laser collimator and two 16″ F/10 receiving optical tube assemblies (OTAs). The laser collimator has manual/computer control capability. One of the twin optical systems is fitted with a CCD camera and used for astrometric and positioning purposes: orientation of the instrument in star-defined coordinate system and observations of natural or artificial space objects. The other may be fitted with a reflected light pulse detector and used for SLR pulse processing or configured for other purposes. The drive has stepper motors with worm-wheel reductors and incremental encoders (resolution up to 0.36″); it is controlled by a FPGA under computer control. Control software runs on a Windows PC and consists of 4 semi-autonomous modules: positioning, ephemeris, laser and astrometry. Preliminary tests indicated that due to the field rotation, which elongates star images in the periphery of the frame, the effective exposure duration is limited to about one minute. At such exposure, stars of magnitude up to 17-18 can be recognized by the software. Frame stacking is proposed to increase this limit by several magnitudes. Theoretically, using frame stacking, it should be possible to reach maximum magnitude of about 22. Mount error model, implemented by the control software, will be used to introduce the necessary pointing corrections. After adjustment of mount mechanics and optimization of mount error model structure the positioning accuracy of up to 5″-10″ is expected. Project No: 1.1.1.2/VIAA/4/20/619.