DLR (CC BY-NC-ND 3.0).
Superposition of 89 single images (1 second exposure time each) taken with the APPARILLO. The line traces are generated by passing orbital objects. The stars in the background serve as reference for an exact position determination by astrometry.
APPARILLO can autonomously capture and process images of solar-illuminated objects in low-Earth orbit. Housed in a weatherproof enclosure and equipped with extensive control and image processing software, the system can measure the angular positions of orbital objects and forward them to existing databases.
The images are captured by a sensitive astro camera with a fast wide-angle lens (10° field of view). A GPS timer ensures the exact timing of the images. With an exposure time of 1 second, passing orbital objects produce a line trace that is clearly distinguishable from the star background.
An astrometry module detects stars in the image and uses their known positions to determine equatorial coordinates of the start and end points of the dash traces. This eliminates the need for precise alignment of the sensor. As a rule, the object positions can be determined to better than one minute of arc.
The data of the detected objects are made available in standardised formats (e.g. Tracking Data Message, TDM), and can optionally be archived or sent to a server for further processing. The measurement accuracy of the observed orbital objects is 1000 m in the direction of flight (along-track) and 100 m perpendicular to the direction of flight (cross-track).
An even higher orbital accuracy of the objects initially detected with APPARILLO can subsequently be achieved by distance measurements with a laser-based (SLR) ground station.
Facts & Figures
More information are available here: https://link.springer.com/article/10.1007/s12567-021-00380-6