Unmanned Systems Technology 009 | Ocean Aero Submaran S10 | Simulation and testing | Farnborough report | 3W-110xi b2 TS HFE FI | USVs | Data storage | Eurosatory/UGS 2016 report

72 same types of business and consumer applications for which planar (2D) NAND is used. SSDs with NAND flash can boost application performance and reduce latency compared with traditional storage media such as hard drives and tape. 3D NAND flash offers the potential for higher capacity in a smaller physical space than 2D NAND. In comparison to planar NAND, 3D NAND can lower the cost per gigabyte, improve electrical use to reduce power consumption, boost reliability, and provide higher data write performance. One disadvantage of 3D NAND against planar NAND though is its higher manufacturing cost, at least at the outset. The production of 3D NAND flash can take place in the same factory as planar NAND, but the layering process adds steps to the 3D NAND manufacturing process, so manufacturers often need to update, expand and/or add semiconductor fabs to accommodate 3D NAND production. If the drive is in a very controlled environment, not in a military-grade application, standard off-the-shelf SSDs can be used, as long as they are not on a critical mission. If the mission is critical then the drive requires the same level of assurance and documentation as all other critical system components, such as where they were manufactured and the level of testing carried out before being embedded into larger onboard systems. These verifications are generally not available from off-the-shelf flash. Need for speed The speed advantage that SSD offers is compelling across the entire range of UAV missions; at the same time, protocols are being used now that can accept uncompressed 4K video at full line rate. Clearly the drive cannot bring such a large amount of data down by an uplink so it is collected when the vehicle lands by removing the data cartridges and replacing them with fresh ones before the next mission. The data is then extracted at a ground station, and although it is possible to use a high-speed download such as 10 Gbit/s Ethernet, even then it could take several hours, so ‘remove and replace’ is the preferred option. Another benefit of the speed is the veracity of the data capture. If even a few frames of an important observation were lost, it could be critical to the success of the mission. The next generation of high-speed, high-performance SSDs and NVMe (non- volatile memory express) interface will allow 12 Tbytes of data in a single drive with up to a Gbit/s of speed. So in theory, one drive will accomplish what would traditionally have taken ten or 12 SSDs. NVMe allows the levels of parallelism found in modern SSDs to be fully used by the host hardware and software. As a result, it reduces I/O overhead and improves performance compared with previous logic device interfaces, including multiple long-command queues and reduced latency. This will lower payload weight and power consumption. Data storage units Data storage units with varying specifications are available from numerous suppliers but their overarching role is to integrate all the interface, control, and memory functions into a single, low-mass, low-power, reduced envelope implementation. The challenges faced by storage providers are similar to most component manufacturers, namely size, weight, power and cost, and in the avionics realm those challenges are particularly stiff. First, while the recording and storage device needs to be fast and have sufficient capacity to hold and secure the mission data, it also has to be able to receive signals from different sources. Somewhere in the system there will have to be a bridge or encoder function for each source, functionality that may be embedded in the recorder, distributed around the platform or even built into the source. The recorder can then be optimised around a few standardised or commodity interfaces (usually including Ethernet and 1553). Second, the recording and storage device needs to facilitate a comprehensive cybersecurity approach, which typically means at a minimum data-at-rest encryption of the media but increasingly also includes a validated software environment via Federal Information Processing Standards (FIPS) and multi- level security architectures so that data with different security requirements can be isolated on the appropriate types and items of removable media. August/September 2016 | Unmanned Systems Technology With a flying time of around 30 minutes, inspection UAVs such as the Microdrones md4- 200 UAV have enough onboard storage for the flight data recorder (Courtesy of Microdrones)