Unmanned Systems Technology 027 l Hummingbird XRP l Gimbals l UAVs insight l AUVSI report part 2 l O’Neill Power Systems NorEaster l Kratos Defense ATMA l Performance Monitoring l Kongsberg Maritime Sounder

78 links and other systems later on in the checklist. The driver then boots up the ATMA control system from the user interface. Although the interface software is switched on, the operation of the autonomy system will remain locked until the operators confirm the checklist has been completed. From the user interface, the driver must switch the control unit from ‘off’ to ‘idle’; this triggers power delivery to the ATMA subsystems. After that, the rest of the ATMA system in the leader vehicle initialises, and that vehicle is ready to move. An engineer should be present in the follower vehicle at this time. The driver in the lead vehicle radios that engineer and tells them to start the follower’s engine. Then, much like on the lead vehicle, the engineer is instructed to pull the parking brake for the rear truck before activating the battery breaker. Once all these steps are carried out, the GPS and navigation data signals on the user interface switch from red to green, indicating that the rear vehicle is receiving the necessary data to follow the path laid out by the lead truck. Leader-follower operation The driver then switches the control panel from ‘idle’ to ‘go’, and the engineer can leave the follower vehicle’s cockpit and move to the lead truck to operate the ATMA user interface while the driver focuses on the road. The follower truck begins moving along a series of GNSS waypoints that are copied from the leader truck’s path (or ‘e-crumbs’ as Factor describes them), ensuring that the approximate dimensions of the road workspace are maintained. For autonomous control of the steering, Kratos has designed a ‘steering ring’ which the operator locks onto the follower vehicle’s steering wheel before moving to the lead vehicle. This device has a gear that interfaces with an actuator connected to the main computer, which then turns the truck left or right as required. The operator can opt to check the video camera in the front of the follower vehicle’s cockpit for a close view of the gap between the two trucks. “From there, you can pause the Follow function,” Factor notes. “For example, if you drive through a traffic light and see in the video that it turns yellow as the lead truck passes through, it’s often safest to stop the follower vehicle there momentarily. “The lead vehicle can carry on, still generating and transmitting e-crumbs and inertial navigation data to the follower. Once the operator sees the light turn green, they can reactivate the Follow mode, and the impact protection vehicle will catch up to whatever the set distance gap is.” The gap to be maintained between the truck will vary from 7 to 450 m, and depend greatly on the operations and how each customer typically carries them out. For example, a highway construction team working in the UK will often prefer to have the vehicles closer together than those in the US would keep them, as an habitual approach to preventing motorists from driving into the work zone. “UK users are also far more inclined than those in the US to conduct the pre-operation checklist at the depot or staging area, and then consider driving it to the work zone in autonomous leader- follower mode, potentially at speeds of about 60 kph,” Factor explains. “It’s dangerous for workers to exit the truck, so in some cases they prefer to make sure the follower vehicle’s cockpit is empty from the outset. And even at that high speed, they generally keep the vehicle-to-vehicle distance tight to discourage drivers from entering the gap.” During early development, the vehicle- to-vehicle distance was difficult to change without going into the software and changing code parameters. However, user feedback indicated the gap would need to be altered dynamically during highway operations, so a slider bar for selecting that distance was added to the user interface. While the driver takes the lead truck along its route, the operator can continually check the control interface to ensure that all the vital systems are working as required. As mentioned, this includes a system of green and red lights on the notebook to show if the GPS data and inertial navigation feeds have been dropped at any point. Also, operating status indicators are August/September 2019 | Unmanned Systems Technology Cameras in the windshield of the follower vehicle and at the rear of the lead vehicle provide multiple vantage points of the work zone and the surrounding highway area