Unmanned Systems Technology 020 | Alpha 800 I Additive Manufacturing focus I USVs insight I Pegasus GE70 I GuardBot I AUVSI Xponential 2018 show report I Solar Power focus I CUAV Expo Europe 2018 show report

10 Platform one A team of former researchers from NASA have unveiled an open framework for UAV development that turns key embedded functions into apps (writes Nick Flaherty). Windhover Labs’ prototype framework is based around the Ubuntu Linux distribution, and has been successfully flight tested to prove its functionality. The researchers are now looking to develop a production version based around a real- time operating system. The aim is to have a core of certified software where other certified apps can be added, for example with an app for image recognition or flight control that would run on the autopilot or a separate microprocessor on the UAV. The same framework can be used on the ground station. The test flight was a key stage in Windhover’s Phase II NASA Small Business Innovation Research programme. The framework is built on NASA’s core flight system and to the FAA’s certification standards in the USA. “We write flight software for space vehicles certified under NASA rules, so we ported that to an avionics board, Aerotenna’s Ocpoc,” said Mathew Benson at Windhover Labs. “We want to be the first flight software to be certified by the FAA. “The flight control system includes the full stack, with drivers, IMU, gyros, state estimation and motor control.” The Ocpoc uses the Zynq FPGA that also includes two ARM processor cores,” said Benson. “The software framework runs on one ARM core with the FPGA used for I/O such as a pulse width modulator controlling the motors, I2C control links to sensors and UART serial data links. “The flight software is loosely coupled to the ground station via a telemetry stream. At the moment, there isn’t a good standard for data exchange for UAVs, and what we might end up doing is driving the industry,” Benson said. The software framework of 500 kbytes or so would be certified, as would any other apps added to the framework. The architecture is such that the individual applications and the configuration can be swapped out at runtime or even in flight. “The big unknown was whether we could execute the flight software in Linux at the rate we need to,” Benson said. “The tests show it runs well in standard Linux, so it will be better on a real-time operating system. “The core framework can be certified and locked down, and each application can have certification independent of the framework, and each system is then certified, which is how it is done in commercial aircraft,” he said. “Any application can run in the framework – it can be a sensor, an effector or the flight software. We also have a scripting engine to allow engineers to write in Python or Java, and we can execute those scripts on or off the vehicle. “We see developers writing an app and shipping with a sensor,” Benson said. “That allows a decoupling of the manufacture of the UAV and the sensor, which right now needs a complex individual port.” The API and most of the flight software will be open source; the ground station software will also be open source, with development tools. The next phase of the project will implement fault detection and recovery including multiple radio receivers, using a separate channel for radio control even in autonomous mode testing. Apps framework for UAVs Airborne vehicles Ground station software is loosely coupled to the Windhover Labs framework run in a UAV June/July 2018 | Unmanned Systems Technology