Epilogue

This book comes to you as a result of the concerted effort of a team of experts in the area of unmanned aircraft systems (UAS) and sense and avoid (SAA), specifically. They were led and organised by the Editor, who himself had the opportunity and privilege to work in a series of large-scale (multi-million) projects in this area in the UK and EU. He is also a leading authority and one of the pioneers of the autonomous learning and dynamically evolving/adaptive intelligent systems. The other contributors include:

• George Limnaios, Nikos Tsourveloudis, and Kimon Valavanis (Technical University of Crete, Greece and University of Denver, CO, USA), the authors of the first chapter which introduces the topic including its historical prospective.
• Andrew Zeitlin (MITRE, USA), the author of the second chapter which focuses on performance tradeoffs and the development of standards.
• Pablo Royo, Eduard Santamaria, Juan Manuel Lema, Enric Pastor, and Cristina Barrado (Technical University of Catalonia, Spain), the authors of the third chapter which describes the integration of SAA capabilities into a UAS distributed architecture for civil applications; this chapter is very valuable, because it provides a systems point of view and puts SAA into the context of UAS as a whole which is not the main topic of this book.
• Xavier Prats, Jorge Ramirez, Luis Delgado, and Pablo Royo (Technical University of Catalonia, Spain) who authored Chapter , on regulations and requirements. This chapter is also very interesting because it starts the topic of human factors, regulations and requirements which (somewhat paradoxically) are a serious (often impeding) element of the implementation of UAS, especially in non-segregated airspace and more routine scenarios.
• Marie Cahhilane, Chris Baber, and Caroline Morin (Cranfield and Birmingham Universities, UK), the authors of Chapter which provides a thorough and professional analysis of the human factors and their role in UAS.
• Stepan Kopriva, David Sislak, and Michal Pechoucek (Czech Technical University, Prague, Czech Republic), the authors of Chapter on SAA concepts. This chapter starts the more technical part of the book covering the methodology of the SAA problem for the vehicle-to-vehicle case.
• Hyo-Sang Shin, Antonios Tsourdos, and Brian White (Cranfield University, UK); the authors who represent the largest European Defence Academy and have extensive research, development, and educational experience in the area propose in Chapter a thorough examination of the UAS conflict detection and resolution problem from the point of view of differential geometry.
• Richard Baumeister (Boeing, USA) and Graham Spencer (Aerosoft Ltd, UK) authored Chapter , which focuses on aircraft separation management using common information network SAA; this approach puts the SAA and UAS in the context of the network-centric warfare concept which is regarded as the future approach.
• David Sislak, Premysl Volf, Stepan Kopriva, and Michal Pechoucek (Czech Technical University, Prague, Czech republic), the authors of Chapter on AgentFly.
• John Lai, Jason Ford, Luis Mejias, Peter O’Shea, and Rodney Walker (Australian Research Centre for Aerospace Automation and Queensland University of Technology, Australia), the authors of Chapter , who provide a detailed report of the visual-based SAA solution that is vital for electro-optical and passive approaches. Sadly, Rod Walker passed away on October 2011 while the book was in production. This book is dedicated to his memory.
• Michael Wilson (Boeing R&T-Australia), the author of the last Chapter on the use of low-cost mobile radar systems for small UAS SAA which provides another interesting approach to the problem based on active (radar) but mobile and cheap systems.

The topic of sense and avoid is pivotal for the viability of the UAS, which themselves are key to the future capability of defence and have huge potential for civilian applications with a great impact on society, the economy, and the environment. The problem may look trivial since the skies are not as congested as our roads and highways, but it is clear from the previous chapters that to reach the requirements of the regulatory authorities and/or to use military UAS safely, a level of safety comparable to (or not less than) that achieved by human-piloted vehicles should be obtained. This is no trivial task, and especially when the only information that can be used comes from passive sensors. However, the direction of the technical, scientific, and technological progress points towards a future with UAS and therefore, this book is very important in its pioneering role and will, quite certainly, be followed by others.