Unmanned Systems Technology 015 | Martin UAV V-Bat | William Sachiti | Sonar Systems | USVs | Desert Aircraft DA150 EFI | SeaCat AUV/ROV | Gimbals

68 M ost UAVs carry stabilised cameras in protective housings to generate imagery for a wide and growing variety of military, public service and commercial purposes. Within their aerodynamic housings they contain a range of technologies, often from different suppliers, that have to be integrated into systems that produce clear images under difficult conditions, and must also be able to locate them in space and time with great accuracy and precision. These systems include cameras with zoom lenses made from materials selected for their ability to transmit the required wavelengths. At the heart of the cameras are detector arrays chosen for their sensitivity to wavelengths of light ranging from the visible and near-infrared (IR) through short-wave IR and into the thermal bands known as mid-wave and long-wave IR. Often installed to complement the cameras are lasers engineered for various purposes such as supplementary illumination, target marking, rangefinding and target designation, in which the beams are pulse coded to work with guided-weapon seekers. Lasers need power of course, which generates heat that must be dissipated, and they also need to be optically aligned with the cameras for accuracy. Increasingly, the digital video signals generated by the cameras are subjected to real-time processing to improve basic qualities such as contrast and sharpness, and also to track moving targets, extract particular features and sometimes perform tasks such as target recognition and even facial recognition. Gimbals with many gimbals Referred to as gimbals, these tightly integrated packages of sensors, electromechanical subsystems and supporting and protective structure must be stabilised on several axes, with the Earth as a frame of reference, to produce clear imagery and precisely geo- referenced target data. The term gimbal technically refers to a support that allows a device mounted on it to pivot about a single axis. A turret can contain several gimbals, the actual number being dictated by the degree of stabilisation required by the sensors, with long ranges and narrow fields of Steady as you go August/September 2017 | Unmanned Systems Technology Peter Donaldson reports on how systems engineers maintain the electromechanical stability of UAV payloads Safran’s Euroflir 410 is typical of a modern large high- performance multi-sensor turret used on tactical UAVs (Courtesy of Safran)