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

45 The third-party autopilot software in the Solara 50 is modelled by Google engineers in the Matlab and Simulink development tools, with the ability to add extensions to enhance the requirements of a specific operation. This takes into account the advantage that, by loitering on-station or circling over an area at high altitude, the system will have a line-of-sight connection to provide the best possible link without having to worry about multi- path interference or any signal degradation as it passes through floors and walls. A base station could be designed to fit into the Solara’s 32 kg payload, but since the propulsion system is a 5.5 kW electric motor, that would leave only 1.5 kW for other activities. Reducing the weight and increasing the efficiency of the motor so that it uses less power would deliver more power for communications. A larger version, the Solara 60, will be 60 m (197 ft) across with a boost to 8 kW of power from more solar cells on its surface, and an increased payload of up to 100 kg (250 lb). The actual base station technology is still to be determined, but it will need to provide a balance between available technology, the power available – known as the power budget – and the availability of PCs or phones to connect to the internet. Mobile phones are designed to receive signals down to -135 dBm, but have limits on the bandwidth they can support. Wi-fi is also widely available on handsets and on every laptop PC, and could be teamed with access points on the ground to provide local networks and reduce the load on the base station. Airborne base stations | Insight high life back to the ground station. The autopilot software, which is used by other UAV companies such as NVOS, in Virginia in the US, handles airspeed, altitude, pitch, roll, heading or turn rate, and includes an ‘autonomous loiter’ function. This allows the aircraft to remain at a fixed altitude and position, or to return to ‘home’ and loiter. In loiter mode, the UAV faces into the wind, drifts with it for a short distance and then powers up to return to the loiter location. This is vital, as it maximises duration by minimising the power required to remain at a constant location. At no point does it turn downwind, as this would result in it having to expend too much energy to compensate. The autopilot also handles landing consistently on a narrow runway, even in a crosswind, by intelligently managing landing pattern and glideslope to minimise over- or undershoot. The large arrays of solar cells on its 50 m wings and the tail are the key to powering the Solara 50 Unmanned Systems Technology | November 2014