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

70 Insight | Datacomms applications, in contrast to the 5.8 GHz- 5.9 GHz band in the EU and the US. 760 MHz has greater range and so can be operated with far lower power than 5.9 GHz, but 760 MHz is not available in Europe or the US as it has already been sold to the mobile industry for 4G services. However, this is an opportunity for ‘cognitive radio’, which is where a highly flexible radio front end ‘sniffs’ for the frequencies available and then re- configures the hardware to match in a software-defined radio (SDR). Such hardware should soon be commercially available. For example, Dutch chip designer NXP has teamed up with Australian mobile specialist Cohda Wireless on the first reference design for connected production vehicles from 2015. The MK4 is based on a chipset called RoadLINK, which combines an SDR radio chip from NXP with a baseband processor and software from Cohda that handles the network, facilities and applications layers for developing the communications subsystems. Adding cognitive radio is a further step. RoadLINK exchanges messages about location, speed and direction across an extended range using the various radio links available, and provides strong security, as it incorporates a hardware encryption accelerator and tamper-proof chip to prevent unauthorised access to the system and reject ‘spoof’ signals from hacking attempts. The chipset supports IEEE 1609 for the US, ETSI TC-ITS for Europe and the Japanese standard at 760 MHz, as well as 2.4 GHz and 5 GHz wi-fi with IEEE 802.11p and the 5.8 GHz Dedicated Short Range Communications (DSRC) specification. This provides a dedicated, licenced 75 MHz band for V2V communications with fast network acquisition time as the cars will be connecting to other vehicles regularly. It also specifies a low latency of 100 ms, which translates into vehicles sharing data ten times a second (10 Hz). An important element here is the reliability of the connection, as the link has to work in extreme weather conditions at the specified 5.8 GHz frequency. This can be particularly challenging because of the absorption of the radio signals by fog, which is exactly the kind of weather where it is most needed. There is also a wider systems issue, as the DSRC data packets need to have priority over non-safety information such as weather reports, which is a key driver in integrating all the processing in a single platform. In Japan, antenna and module specialist ALPS Electric is already using NXP’s RoadLINK chipset for in-car applications, and AEC-Q100 qualification for automotive systems is scheduled for 2015 so that it can be shipped in vehicles. Meanwhile, in the US, General Motors has announced a Cadillac model, the CTS Sedan, for 2017 that will have V2V coupled with a sensor fusion of camera, GPS, radar and map data. The Super Cruise system in the car is a semi-automated advanced driver assist technology that includes hands-off lane following, braking and speed control in certain highway driving The DDS Publish Subscribe architecture separates functions into publishers and consumers to create a real-time comms network that is independent of hardware and operating system There is an opportunity for ‘cognitive radio’, which is where a radio front end ‘sniffs’ for the available frequencies November 2014 | Unmanned Systems Technology