Unmanned Systems Technology 025 | iXblue DriX I Maintenance I UGVs I IDEX 2019 I Planck Aero Shearwater I Sky Power hybrid system I Delph Dynamics RH4 I GCSs I StreetDrone Twizy I Oceanology Americas 2019

80 for example having two batteries, but the interface design is also important. One approach is to have a hub in the GCS that is separate from the laptop or tablet and integrates the different accessories, rather than plugging them directly into the computer via a USB port. For example, if the data link is connected to the computer, if there is a problem then the comms to the UAV will be lost. By having the telemetry data and control link, manual control and video feed on the separate hub in the GCS, the mission can still continue under autonomous operation. That can allow more rugged connectors from the hub to the computing engine, using protocols such as RS-232 and RS- 422 as well as Ethernet. Joysticks/controllers While the traditional trackpad on a laptop is often used for mission planning, or a joystick for aircraft control, there are innovations in the HMI accessories for a GCS. One of these is to use additional sensors in a mouse to create a 3D controller to fly an aircraft or control an arm attached to a ground vehicle. The approach uses Hall effect sensors to measure the movement of the top of the mouse in all three axes, linked to a 12-bit analogue-to-digital converter. This 12-bit resolution gives a 14º resolution on the pitch and roll of the aircraft. This has an advantage in that the mouse function can be used for mission planning as well as a back-up to manual control of the UAV, and it can provide a redundancy mechanism in the GCS alongside a joystick. That will become even more significant when monitoring and controlling multiple UAVs in a swarm with a 3D view. The requirement for rapidly panning and zooming around a map, selecting different aircraft and their camera views – and manipulating those views – means the mouse’s performance is becoming more important. That is not just with regard to UAVs. A research project is looking at how to use a 3D mouse to control a tele-operation arm, for example on a firefighting or bomb disposal UGV. It is studying how to use the mouse initially to put a target on the screen and then use the mouse to control the orientation of the arm. Simulation One advantage of combining the mission control and autopilot software with the GCS system is that it opens up the opportunity for simulation. One example of a hardware-in-the-loop (HIL) simulator combines two autopilots to check everything in a mission. It can fully test the mission design, introducing failures into the flight plan and autonomous operation to simulate a full mission, including stopping the engine and testing the auto-rotation. The GCS developer also uses the HIL simulator to develop the software, to display all the parameters from the autopilot in every scenario. Modelling A digital elevation model (DEM) in the ground station software provides good- quality altitude data without using a sensor such as a radar or laser altimeter, so it can be used as a back-up if there is a problem with the sensor. It also helps with the flight planning, as the GCS software can adjust all the settings for the aircraft, such as those for the actuators. GNSS satellite altitude and parametric altitude data can also be integrated into the GCS software to allow the UAV to fly into conflicted airspace, and a .uav file log with all the data allows the HIL simulator to replay a mission to evaluate that performance and see up to 80 parameters stored during the flight. This can be used to provide assurance to regulators by demonstrating that a system can meet collision avoidance and ground avoidance rules. The GCS software can then integrate the management of no-fly zones, telling operators that there might be issues with the mission plan. The plan can then be edited in real time via point and click in the software to take account of new data. The DEM can also be used to check if the flight plan would make the UAV crash, or if two waypoints are close to each other and that there is a significant difference between the altitudes. The system will also April/May 2019 | Unmanned Systems Technology Focus | Ground control stations The GCS is a key part of a UAV’s flight control system, and can be incorporated into a hardware-in-the-loop simulator (Courtesy of UAV Navigation)