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Ground-Based Optical Space Surveillance Sensor

Ground-Based Optical Space Surveillance Sensor

We have developed a proof-of-concept demonstrator capable of continuously (night-time) monitoring of all GEO objects in a limited field of view (approximately 5 degree x 5 degree), with real-time catalogue updates online.

Figure 1: image of our proof-of-concept demonstrator.

Our data is currently observation based, we record and publish observations, matched to objects by proximity to TLE projected orbits. Many objects are not found in the public catalogue and are listed as ‘unknown’.

The object position (RA, DEC) and brightness (apparent astronomical magnitude) are recorded complete with individual uncertainties for each measurement derived from the observation itself. With the proof-of-concept demonstrator we achieve real-time (currently 8 second lag) blind detection of GEO objects with an astrometric accuracy of approximately 2 arcseconds rms (varies depending on observation conditions), which corresponds to approximately 350 metres at GEO orbit. Our sensitivity limit in Durham, observing at 25 degrees elevation is approximately 15th magnitude. In a darker site closer to the equator this would be improved.

Brightness and position are monitored continuously through the night enabling us to characterise the object and its pattern of behaviour. We observe regular brightness variations due to the changing state vector between the 3D structure of the object and the solar phase angle.

Figure 2: an example of the data we collect from our demonstrator. From left to right, photometry (light curve), astrometry (position) and object image.
Figure 3: another example object, also listed as GEO communications satellite but showing significantly different structure.