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80 Show report | InterDrone 2018 services for non-airborne unmanned platforms,” he said. “There’s been such a surge in UAV photogrammetry that people forget about UGVs capturing geospatial data that need solutions for efficient access, hosting and sharing.” Vertical Partners West had on show its new Venom battery charging and management system (BCMS) as well as the new Venom Commercial Series batteries, which use data analytics-driven BMS technology to make fleet battery management safer and more cost- optimisable. “Unlike most BMSs, our battery has 8 Mbytes of EEPROM data capture within it, so it can intelligently monitor and transmit its own health metrics and conduct its own diagnostics and safety lock-outs,” said Keith Wallace. The Commercial Series batteries can also be interfaced with a UAV’s flight controller via CAN bus or I2C so that users can be informed on the precise current draw, temperature fluctuations and the many other real-time metrics generated during flight. “The BCMS transmits all this captured information into the cloud, where it can be re-examined over the life of the battery,” Wallace said. Drawing on this data, the BCMS is able to produce feedback on battery health and historical usage, and notify users of faults and potential failures before they happen. At the moment, the Commercial Series consists of a 6S 22 Ah 22.2 V version that weighs 2.8 kg, with more coming soon. The BCMS comes in a Pro version providing 720 W of charging power and an Ultra version providing 2200 W. ComNav Technology displayed its new K705 GNSS OEM board, its smallest system so far, weighing 22 g and measuring 5 x 4 cm. “It supports full constellations – GPS, BeiDou, GLONASS and Galileo – and is triple-frequency,” said Wade Zhang. “And it supports the L band for precise point positioning satellite-based corrections. The module is also fully shielded to protect against EMI generated by other electronic components onboard UAVs.” The receiver nominally consumes 1.3 W of power, up to a maximum of 1.64 W when working at full capacity. It also comes with a Delta Phase filter, which uses the company’s own algorithm to give relative positional accuracy (pass to pass) to 20 cm without needing any corrections from base stations or other sources. GEM Systems attended the exhibition to display its range of optically pumped potassium magnetometer payloads, for UAV manufacturers and operators seeking to engage in mineral exploration, pipeline detection, unexploded ordnance (UXO) location and other missions centred on magnetic data acquisition. AirGrad, the largest and newest system from GEM Systems, acts as a gradiometer by integrating two potassium (GSMP-35U) magnetometers on gimbals within its tail pods. “That means you can improve spatial resolution over total field measurements alone because you’re also accounting for the gradient between the two sensors and their readings,” explained Ivan Monroy Ortiz. “Enhancing near-surface, small or weak anomalies makes it useful for high- risk UXO missions, but you will need a UAV that’s powerful enough to carry the 8.5 kg payload.” The AirGrad also houses a GPS receiver, an IMU, a laser altimeter and a 2.4 GHz radio link for transmitting data in real time to the linked ground station. The AirGrad is towed at a fixed distance of 10 m from the UAV using a Dyneema tow cable to ensure negligible magnetic interference. The GSMP-35U operates using an opaque glass vapour cell containing gaseous potassium, pumped by light of a particular wavelength to excite electrons to a metastable state. They decay until depolarised, at which point RF power is applied to the cell to re-excite its electrons until it is opaque again. As this frequency varies with the presence and strength of magnetic fields, magnetic readings can be discerned by detecting the light’s modulation and measuring its frequency. Doosan Mobility Innovation unveiled its flagship DP20 hydrogen fuel cell power system for medium-sized commercial multi-rotor aircraft weighing 16-20 kg. The system uses hydrogen gas to produce about 2.1 kW of power (up to a maximum of 3 kW). “For dispensing as well as refuelling, the system uses a regulator and valve connectors developed with and sourced through third parties, because the tank had to be custom-made,” said Doosoon Lee. “A COTS tank couldn’t be used because we need to take the aerodynamics and centre of gravity into account for each aircraft. In addition, miniaturising the fuel cell stack – given requirements for weight, power output and so on – was probably as complicated if not more so than getting the tank’s regulator and balance right.” The two fuel cell stacks weigh 1.5 kg each, and the tank can weigh 3 or 4.3 kg, depending on whether a 7 or 10.8 litre version is used. The system also uses two 1800 mAh batteries, and everything (including stacks, fuel tank and regulator valve) is housed in an enclosure measuring 610 x 550 x 280 mm. October/November 2018 | Unmanned Systems Technology ComNav Technology’s K705 GNSS OEM board is its smallest system yet