Unmanned Systems Technology 010 | nuTonomy driverless taxi | Embedded computing | HFE International marine powertrain | Space vehicles | Performance monitoring | Commercial UAV Show Asia report

78 Also, the UAS interface board allows for a wide range of power supply inputs – from 6 to 30 V – to enable easy integration with a UAV’s power supply bus. An event marker is included to synchronise a camera payload’s shutter with GNSS time, for collecting aerial survey data with RTK precision. 32 Gbytes of survey imagery can be logged on board using the interface board’s micro-SD card. Septentrio’s GeoTagZ software is also available for enhancing aerial survey functionality. Patricia Joris commented, “GeoTagZ effectively removes the need for ground control points by updating the aerial photographs with high-precision camera locations. The receiver logs time-stamped, shutter-synchronised events from the camera during aerial survey, and the software uses these to embed RTK-level camera locations into the images.” Kobayashi Precision, from Japan, used the show to display its BT-86 engine, which allows UAVs to achieve an accumulated flight endurance of 24,065 km and a duration of 201 hours. The BT-86 is a two-stroke engine that uses a horizontally opposed twin-cylinder configuration and, as its name suggests, displaces 86 cc. The system is fuelled by two stroke pre-mix (a mixture of gasoline and oil for lubrication) and uses a single HDA-series carburettor from Walbro Japan, a US-based manufacturer. Capacitor discharge ignition occurs through the engine’s flywheel magnet. The pulse generated by the flywheel and ignition coil flows to the spark plug, a BPMR7A type from NGK Corporation. Fuel consumption is quoted as 599 g/kWh, and maximum power is about 4.1 kW at 9000 rpm, giving the UAV a cruising speed of 100 kph and a flight endurance of more than five hours. The engine itself measures about 252 x 205 x 160 mm, and its aluminium structure results in a dry weight of 2.95 kg. As Masazumi Kobayashi told us, “The structure is aluminium for the crankcase and cylinder, and iron for the crankshaft and con rod. Because this engine is designed mainly for UAVs, we had to keep it lightweight while still high in power output.” Ascent Solar Technologies has developed a line of lightweight, flexible, large-area solar cells using copper indium gallium selenide (CIGS), that are being used in the production Silent Falcon UAS. CIGS is deposited and bonded onto flexible plastic substrates, allowing the cells to be patterned without cutting through the plastic, and provide modules at a specific voltage according to end- user requirements. This flexibility means the in-production solar blanket using these modules can be integrated directly into curved surfaces such as the wings or fuselage of a UAV during composite fabrication without significantly affecting weight or aerodynamics – a standard aerospace-grade CIGS solar cell weighs 400 g/m 2 and produces 110 W, although the weight can be reduced for other applications. “Because our technology is flexible, lightweight and able to generate higher voltages than traditional solar cells, our production modules are suitable for anything from space applications and high-altitude long-endurance vehicles, to portable military-grade power applications,” the company’s Dr Joseph Armstrong said. October/November 2016 | Unmanned Systems Technology Septentrio’s AsteRx-m GNSS receiver is for micro-UASs with tight SWaP constraints The BT-86 two-stroke gives a cruising speed of 100 kph and a duration of about 200 hours Flexible CIGS solar cells fitted to the Silent Falcon UAS