Unmanned Systems Technology 003 | UAV Solutions Talon 120 | Cable harnesses | Austro Engine AE50R and AE300 | Autonomous mining | AUVSI 2015 show report | Transponders | Space systems

73 Transponders | Focus operators may be able to use relatively wide transponder transmissions bands of around 265 kHz, other operational environments may limit these to about 25 kHz to ease pressure on the available radio spectrum. SDR techniques allow the user to reprogram the transponder to this end, rather than having physically to reconfigure the transponder hardware. Moore’s Law In much the same way as consumer cell phones and computers have become smaller over the years, so the same trend is being witnessed regarding transponders for unmanned vehicles. In the UAV domain in particular, aircraft designers are increasingly demanding transponders with a lower SWaP burden, so that space and available power can be freed up to allow the integration of additional subsystems or payloads to improve the craft’s capabilities. A major contribution to reducing this burden comes from Moore’s Law, the theory proposed by chip maker Intel’s co- founder Gordon Moore that the number of transistors on a single chip doubles every 18 months. The more transistors on a single chip in a transponder, the less space needed for circuitry, hence the smaller the transponder can become. Moreover, in the future, transponders may cease to become single ‘black box’ units, and may instead be combined with other unmanned vehicle subsystems such as autopilots (in the air and sea domains), onboard computers and sensors. In the air domain, transponders play an important role in the eventual integration of UAVs into unsegregated airspace, where they will fly alongside manned aircraft and be supervised in a similar fashion by ATC. For this to occur though, transponder technology will have to meet national civil aviation requirements to ensure that UAVs can be handled and treated in the same manner as manned aircraft. In addition, UAV transponders will have to meet stringent safety requirements to safeguard the comms links they share with ATC in terms of interference, both accidental and deliberate. Even so, this could be less of a development burden than it might seem. Given the high standard of safety requirements that already characterises the UAV transponders used by military operators, migrating such technology into a civil environment might not be as cumbersome as expected. Once UAV transponders are shown to be safe for use in ATC-administered airspaces, an increasing number of operators may choose to buy and use them, which could then reduce procurement costs. Mode-S An important issue regarding transponder research, design and development concerns their future evolution for UAVs. Around the world, major changes are planned for the air traffic management (ATM) of civilian as well as military craft, and this has implications for the UAV community as it impinges on the long-term goal of seamlessly integrating unmanned aircraft into airspace used by their piloted counterparts. At the moment, complex arrangements are needed to ensure the safety of manned craft when sharing airspace with UAVs. However, ATM procedures are changing throughout the world as a result of initiatives including ‘NextGen’ (Next Generation Air Transportation System) in the US and the EU’s Single European Sky (SES). NextGen is being led by the Federal Aviation Administration, SES by the Unmanned Systems Technology | Summer 2015 More transistors on a single chip in a transponder means less space needed for circuitry, so the transponder can become smaller This transponder is best suited to multi- mission UAV use up to 60,000 ft, and complies fully with the latest ADS-B standards (Courtesy of Trig Avionics)