G-MAP: A novel night vision system for satellites
Authors: Miletti T., Maresi L., Zuccaro Marchi A., Pontetti G.
Autors Affiliation: Dipartimento di Fisica, Università Degli Studi di Trieste, Via Valerio 2, Trieste, 34127, Italy; ESA-European Space Research and Technology Centre, Keplerlaan 1 – P.O. Box 299, AG Noordwijk, NL-2200, Netherlands; G and A Engineering S.r.l., Località Miole 100, Oricola (AQ), 67063, Italy
Abstract: The recent developments of single-photon counting array detectors opens the door to a novel type of systems that could be used on satellites in low Earth orbit. One possible application is the detection of non-cooperative vessels or illegal fishing activities. Currently only surveillance operations conducted by Navy or coast guard address this topic, operations by nature costly and with limited coverage. This paper aims to describe the architectural design of a system based on a novel single-photon counting detector, which works mainly in the visible and features fast readout, low noise and a 256×256 matrix of 64 µm-pixels. This detector is positioned in the focal plane of a fully aspheric reflective f/6 telescope, to guarantee state of the art performance. The combination of the two grants optimal ground sampling distance, compatible with the average dimension of a vessel, and overall performance. A radiative analysis of the light transmitted from emission to detection is presented, starting from models of lamps used for attracting fishes and illuminating the deck of the boats. A radiative transfer model is used to estimate the amount of photons emitted by such vessels reaching the detector. Since the novel detector features high framerate and low noise, the system as it is envisaged is able to properly serve the proposed goal. The paper shows the results of a trade-off between instrument parameters and spacecraft operations to maximize the detection probability and the covered sea surface. The status of development of both detector and telescope are also described.
KeyWords: Computer vision; Economic and social effects; Fishing vessels; Light; Orbits; Particle beams; Photons; Radiative transfer; Satellites; Space flight; Surface waters; Telescopes, Earth observations; Ground sampling distances; Radiative transfer model; Single photon counting; Single photon counting detectors; Small-satellite; State-of-the-art performance; Surveillance operations, Feature extractionDOI: 10.1117/12.2195028