Autoaligning System for Short-Range Free Space Optics Links

The paper presents a system for autonomous pointing, acquisition, and tracking of an FSO fixture. The initial manual alignment of the FSO link is a challenging and time-consuming operation. Therefore, the proposed system solves the problem of the auto_alignment operation of two FSO transceivers at a short distance (=1 km). The system uses a Schmidt-Cassegrain telescope placed on a tripod with an altazimuth mount. There is a 1550 nm laser beam used for data transmission and a 850 nm laser beam, which is used for acquisition and coarse tracking. The autonomous initial pointing is performed by reading geographical position coordinates from the GNSS module which are sent by LoRa technology to the counterpart FSO fixture. After this scanning and positioning by four-quadrant photo diode, the receiver's Field of View (FOV) is aligned with the transmitter.