Use of an optical sensor as a directional antenna

ABSTRACTThe work presented in this paper is related to the study of a system that uses optical sensors as directionalantennas for locating laser sources. The use of large area optical transducers, which have a specific angulargain, allow us to design a system that is sensitive to angular displacements of a laser source within the sensorfield of view. Through specific algorithms it is possible to obtain an estimate of the direction of the planewaves striking the sensor head. This can be achieved with a resolution better than 1° using only four discretesensors and covering a 180° field ofview. Since the estimate ofthe angular position ofthe laser source is doneon a pulse per pulse basis , this system is not affected by any fluctuation or degradation of the signal duringthe time of exposure.Sensor modelling, radiometric analysis and algorithms are presented. Specific trade-offs regarding resolution,angular coverage and SNR are also discussed.Keywords: Optical sensor, antenna, source location, line of sight detection.1. INTRODUCTIONWhen considering source location and guiding functions with a classical optical system, inevitable designtrade-offs are well known. One of the major difficulties is to ensure that a specific system can cover a largearea of surveillance and be able to locate point sources with the desired resolution. The solution usually lies on