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

69 metrics such as the battery use, fuel consumption and the last transmission it received before an event, such as a crash or systems failure. Medium and large unmanned platforms can capture raw video and data streams at increasingly high rates as the addition of metadata becomes an industry standard. That places a high demand on the platform‘s storage capacity, and the demand can be met in three ways – through the embedded storage capacity of sensor platforms such as cameras, through the provision of onboard storage units, or by sending the data back to a control station. The exact solution will depend on the size of the platform and its mission criteria, but is often a combination of all three. Solid-state drives There are still some hard drive and indeed hybrid solutions in use, although the market is rapidly moving to solid- state drives (SSDs). Deciding which storage medium to adopt will depend on the weight and durability required for any particular solution. Traditional rotating storage media and tapes can still be used when speed is not required, when access time is not critical and when it is not used in a rugged environment. The prime reason for their use in this instance is that they are, for now, slightly less expensive, although over time the price difference will quickly erode. Price is always a sensitive issue. Given the disparate specifications of storage media, comparing like for like on systems is not easy. One manufacturer reports that when talking about similar access speeds of the drives then the price points are coming closer together. The challenge with the pricing of SSDs is that there are a number of options for individual drives – security measures, high-temperature ratings, whether ruggedised and different coatings – that will push the price up or down. So when someone tries to give you a general pricing you really have to drill down to exactly what is being sold. There is no doubt that flash memory, particularly NAND flash memory, is becoming the medium of choice. NAND flash memory is a type of non-volatile storage technology that does not require power to retain data. It does not have the mechanical limitations and latencies of hard drives, so an SSD is attractive when considering speed, noise, power consumption and reliability. Aside from unmanned platforms, flash drives are gaining traction as secondary storage devices in mobile devices. They are also used as substitutes for hard drives in high-performance desktop computers and some servers with RAID and SAN architectures. However, there remain some aspects of flash-based SSDs that make them Data storage | Focus Unmanned Systems Technology | August/September 2016