Issue 40 Unmanned Systems Technology October/November 2021 ANYbotics ANYmal D l AI systems focus l Aquatic Drones Phoenix 5 l Space vehicles insight l Sky Eye Rapier X-25 l FlyingBasket FB3 l GCS focus l AUVSI Xponential 2021

78 Focus | Ground control stations continued connectivity while their users move around with them. As with their physical control interfaces, these are custom-designed to ensure a modicum of consistency in their wave propagation and latency. While UAV autonomy is now robust enough that few commercial UASs truly need persistent control links from a practical or safety standpoint, providing a GCS with a poor data link could be considered a breach of regulations that require an operator in the loop at all times. It is common now for high-end GCS manufacturers to offer an initial development kit as the first part of a back-and-forth process to deduce the precise form factor, interface design and ancillary systems needed to produce a hardware platform that works and feels exactly how an unmanned systems manufacturer or operator requires. That process can take anywhere from a week to a year, but should cover the types of controls, radios, antennas, operating system and ruggedisation that suits each end-user, as well as the amount of RAM, hard disc space and number of I/Os they require. Well-known standards such as Mil- Std 810G are often adhered to, but GCS development processes these days can also unearth less well-known but highly useful design standards. For example, IEC 60945 provides requirements on EMC for navigational aids in the maritime space, which can be particularly stringent with respect to the selection of radios – one GCS designed to this standard has made innovative use of a Power-over-Ethernet cable in order to meet its requirements. Data links As mentioned, various smart radios and advanced antenna systems are available for optimising the connectivity between small tablet GCSs and unmanned vehicles. However, when running high-stakes missions that require constant visibility of the location, health status and survey data stream of a vehicle, using a data link system with a direct line of sight to the unmanned vehicle becomes imperative. For such missions, it can pay dividends to install a dedicated tracking antenna and radio system in an open space or atop a building with a clear view towards the unmanned system’s operating location. The antenna or radio can then connect with the GCS via an extended USB or Ethernet cable – or even remotely using wi-fi – to ensure as high- fidelity a link as possible. High-end products designed with this use-case in mind have various advantages over smaller data links packaged with the GCS. The most straightforward is that the antenna can be elevated flexibly using telescopic or swappable masts, improving the range and quality of connection and reducing interference caused from the ground and surrounding structures and devices. Also, decoupling the data link from the packaging of a GCS allows different comms technologies to be selected individually to suit the end-user’s budget and mission requirements. For example, there is a wide variety of antenna designs available. There are now sector antennas that can track ADS-B signals from 500 km away (or FLARM traffic awareness up to 70 km away) for a comprehensive unmanned traffic management (UTM) capability, and while such systems are directional antennas that tend to operate on beam widths of 60- 120 º , there is no reason why an end-user cannot customise a solution composed of three to six sector antennas arranged radially for 360 º coverage, if needed. Alternatively, a system could be designed with embedded control actuators and precision encoders to enable an antenna to autonomously point itself as needed to maintain coverage of an unmanned vehicle based on received location and heading information. With automated tracking, any type of directional antenna could be incorporated to match the operator’s familiarity or budget. As with the unmanned vehicle itself, several key subsystems would be needed to estimate the position and attitude of the tracking antenna, such as October/November 2021 | Unmanned Systems Technology Some ground comms stations are being designed for permanent installation on buildings, providing persistent comms to routine survey or delivery UAVs (Courtesy of Aerobits)