Unmanned Systems Technology 001 | UAV Factory Penguin C | Real-time operating systems | Hirth S1218 two-stroke twin | Base stations | ASV C-Enduro | Composites | Datacomms

34 Focus | Real-time operating systems well established for authenticating and protecting information between two end- points, distributed systems have their own challenges in being kept secure. For example, if an IP packet is sent to, say, 20 nodes but without authentication of either the sender or other nodes in the network, it can leave the system vulnerable. The hard part with multicast is not how to encrypt the data but how to distribute the encryption keys securely without using a single shared key. This is a key problem for real-time distributed systems but a vital one to address. Standards To an extent the standards for real-time processing and communications are driving the direction of the technology development. One key standards group is FACE, the Future Air Compatibility Environment, which is centred on Posix – a real-time and more complex version of Linux – and the ARINC standard. There is also the UAS Control Segment (UCS) architecture, another effort to standardise how unmanned and autonomous systems from UAVs to robots are aligned with FACE and include the ground stations as well as the airborne craft, and which is again centred on Posix. The difficulty with standardising this part of the software stack is how to come up with the right profile for Posix, which is why the standards-setting process is taking time. Lots of different efforts can develop for open standards but not necessarily ensure that these standards are safe and secure. Also, Posix was designed for larger systems on cards and in racks, but space and power in autonomous vehicles are limited. As a result, RTOS developers are putting Posix layers on top of popular commercial real- time operating systems to make sure the Posix elements can meet the same level of safety and security. As the UCS has moved into ground stations, so there has been a demand for a secure, reliable file system. In response, PJFS – the partitioning journal file system – was built to meet the same levels of safety and security as an RTOS, and has been implemented with 200 lines of code compared to the 100,000 lines in Linux. These extra functions also add complexity to the system an RTOS has to manage. For example, if power is lost then what happens to the file system? The goal with PJFS is that it has to be fault-tolerant to any kind of file system starting up without having to do a full check of all the files in the system. There has been speculation that development of standards in the Internet of Things could simplify the software The hard part with multicast is how to distribute the encryption keys securely without using a single shared key The UCS architecture is a common framework for unmanned aircraft being development by the US armed forces November 2014 | Unmanned Systems Technology