Issue 45 | Uncrewed Systems Technology Aug/Sept 2022 Tidewie USV Tupan | Performance monitoring | Bayonet 350 | UAVs insight | Xponential 2022 | ULPower UL350i and UL350iHPS | Elroy Air Chaparral | Gimbals | Clogworks Dark Matter

104 and trustworthy approach, but of course it will increase the thermal management burden of the gimbal’s subsystems. Adding a dedicated heater for the IMU can also conflict with the need to cool internal electronics and IR sensors though, so significant insulation and isolation features in the IMU’s PCB, along with judicious use of aluminium heat sinks around the heater, can help. Lastly, it is vital to remember that today’s high-end gimbals are almost all geo-referenced systems. Wherever possible, the gimbal must ‘know’ where it is, in GNSS and altitude terms, and be able to discern where the target is based on pointing direction. Even when there’s no ‘target’ – in filming work, say – high-resolution GNSS data can be critical for determining acceleration and velocity to compensate for issues such as drift in the horizon or inertial readings. In this regard, the UAV itself can once again be a source of vital data for the gimbal. As precise pointing and tracking requires not only GNSS and altitude information but also compensation for the host vehicle’s heading – as this has an impact on the relative angle between gimbal and target – integrating a data connection into the gimbal for taking GNSS heading information from an external source such as the autopilot is a straightforward way of improving the gimbal’s tracking and pointing accuracy without needing to make major alterations to its architecture. However, the speed and resolution requirements of data inputs for gimbal pointing are generally much higher than those of uncrewed vehicle navigation systems. Manufacturers looking to guarantee a minimum level of pointing accuracy can therefore aim to use or provide a dedicated navigation module off-board from the gimbal, for providing real-time, high-precision updates on position, heading and so on. That can be crucial for multi-rotors, USVs or UGVs capable of rotating on the spot where vehicles’ headings are often unclear, and hence can come with different combinations of subsystems such as dual GNSS antenna inputs, high- end inertial sensors and barometers. The frequency of laser rangefinders across gimbal products is also increasing in response to a demand for accurate geo- pointing. Millisecond-rate data updates on the distance to a target, as well as the rate at which that distance is changing – and by extension the velocities between vehicle and target – inform the gimbal very closely on how best to zoom, pan, tilt or roll to continue tracking it. The high quality of this information is why defence and security gimbals come increasingly with laser devices, given the importance of target tracking to these users, not to mention their ability to pay for such expensive laser systems. Structure and materials Materials choices in gimbals, particularly with regard to housings, continue to follow the same logic as most other sections throughout a UAV, being based on whatever quality the gimbal maker and systems integrator wants to eradicate most. In general, plastics are ideal for reducing materials costs, carbon composite is best for reducing weight, and aluminium wins out for reducing or extracting heat. With the most prominent trend in gimbal design being the integration of new and more powerful GPUs, it August/September 2022 | Uncrewed Systems Technology Focus | Gimbals Novel use of data connectors, off-board navigation and more can be critical to getting the right data for accurate pointing and tracking (Courtesy of Merio) Aluminium, composites, plastics and more are key to balancing thermal, weight and cost concerns in gimbals (Courtesy of Shotover)