Horizon Acquisition Experiment
The Horizon Acquisition Experiment ( HORACE ) is an experiment that is being carried out as part of the REXUS program by EuroLaunch , a cooperation between the German Aerospace Center (DLR) and the Swedish Space Corporations (SSC) Recognition of the earth's horizon from space goes.
A new approach for an attitude determination system for satellites that works reliably even under very unfavorable conditions, such as uncontrolled tumbling in space, is to be shown, because unlike conventional earth sensors, HORACE processes image data from a normal camera that works in the visible spectrum .
Description of the experiment
The structure of the system basically consists of a camera that can record image data at high frame rates, and an embedded system on which powerful algorithms are implemented that are capable of recognizing the horizon line in individual images almost in real time and a vector (for the time being only in a 2D projection of the earth). Originally, a specially programmed FPGA was provided for the embedded system in order to guarantee real-time processing of the data. However, since this was too power-hungry for the sounding rocket, a conventional embedded computer with an x86 architecture was used, on which an adapted Arch-Linux was responsible for the evaluation of the image data.
Since the experiment flew with the REXUS-16 rocket as a payload, the camera module was mounted just below the tip at an angle of 90 ° to the longitudinal axis of the rocket, in order to ensure the horizon visibility during the flight of the rocket. The REXUS-16 rocket was launched on May 27, 2014 from the rocket station in Esrange, near Kiruna, in Sweden.
After the rocket was recovered, the vectors obtained and the detected horizon lines would have been compared with the data from the REXUS rocket to ensure that the system was working reliably. However, both cameras of the experiment recorded strongly overexposed images during the flight due to technical problems. Due to the good results of the simulations preceding the flight and the complete operational functionality of the developed communication framework, the experiment can still be rated as a partial success. Despite the problems of the experiment, follow-up projects are planned in order to achieve the long-term goal of an operationally usable sensor.
meaning
This approach to horizon detection is still in its infancy, but should the system prove itself, it would be a very big step towards fully autonomous satellites that can recognize their position without human intervention and, if necessary, stabilize it.
Since this concept is very software-intensive, it is conceivable that in the future satellites with a correspondingly existing optical payload will be able to perform a horizon detection simply by means of a software upgrade with an adapted HORACE version without the on-board hardware of the satellite being blocked Beginning would have been designed for that.
Web links
Individual evidence
- ^ A b The Project - Horace
- ↑ HORACE - HORizon ACquisition Experiment . University of Würzburg
- ↑ Local news RadioGong ( Memento from November 17, 2017 in the Internet Archive )
- ↑ Blog post about the activities after the start on horace-rexus.de