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developed and evaluated as a simple system consisting of communication terminals and using no communication infrastructure facilities such as a central control equipment in a hub station. e MAC layer (media access control layer) protocol used is under international standardization as IEEE802.15.8.A helicopter pilot or a drone operator, with a drone mapper mounted on their cra, is able to know other drone mapper-mounted drones or helicopters as follows: on their tablet terminal screen, relative locations of other ying objects, if they are equipped with drone mappers, are displayed at a refresh rate of 2 to 4 times per second with their own cra centered on the map just like a radar chart (Fig.14). When a drone or helicopter comes close in a certain horizontal or vertical distance, its icon turns red—working as an alert system, although being a simple system. We have a plan to enhance the graphical user interface (GUI) mentioned above through discussions with drone users and manned aircra users.Note that we have conrmed in a ground test that the longest wave range of a drone mapper is over 9 km at shortest, because it uses a wave with a narrower bandwidth compared to the previously mentioned Tough Wireless and also uses a broadcast-type protocol.6ConclusionsFor a long time before the recent drone boom, we have noticed how promising unmanned aerial vehicles are, and how essential the wireless technologies are for them. So, we have accumulated eld experiences one by one through operating a proven small unmanned vehicle made in America. It had been used widely in the world, as we ac-quired knowhow on wireless technologies for drones, and we have been analyzing a variety of problems and studying the solutions. While we had been putting eorts into xed-wing unmanned aircra operations, many media companies paid attention, having interviews with us—ve TV pro-grams were broadcast from stations including NHK and TV Tokyo, and 11 articles were published in newspapers including general papers.Furthermore, based on the abovementioned eld expe-riences, we have developed technologies for beyond visual line-of-sight/beyond radio line-of-sight ight and tech-nologies for sharing drone information, applicable to such beyond line-of sight-situations, where we targeted multi-rotor type drones as well.On the other hand, for social contributions by using our technologies, we started joint studies with a research institute who aims to develop drone-based radioactivity monitoring systems usable in the vicinity of a nuclear power plant. In addition, we have started joint research and development projects with an electric power plant com-pany who wants to apply our technologies to their power infrastructure inspection jobs in mountainous areas where it is dicult to have line-of-sight conditions, and moreover a venture company aiming for the expansion of their drone business.Furthermore, jointly with research institutes and com-panies, we received a collective research contract (staring in 2017) order from the New Energy and Industrial Technology Development Organization (NEDO). So, we have already started activities for further advancing the technologies we described in this article and developing systems working with better performances in practical situations. We hope, through our activities mentioned so far, to secure our competitiveness in drone operation technologies which are expected to grow, and to contribute to society.AcknowledgmentsAs previously stated, we conducted a part of the re-search and development described in this article as contract research (Research and Development for the Radio Wave Resource Augmentation) of the Ministry of Internal Aairs and Communications and the Impulsing Paradigm Change through Disruptive Technologies Program (ImPACT) of the Cabinet Oce.Here, we express our appreciation to the organizations or business operators for their cooperation in the proof-of-concept experiments. We worked in collaboration with the FiF14Mounted done mapper on a drone, and locations of nearby drones displayed on a tablet screenA simulated drone station placed on the ground (used as another’s drone)Drone B(other’s drone)Drone station A(your drone)Ground control stationA display on a tablet monitor screen(showing on a map, all the mapper stations with locations, altitude, and bearing angles)* Drones coming into a range of certain distance from your drone are changed to red(simple alarming system)Test site: AobayamaCampus, Tohoku Univ.(Sendai)BLOS from the ground control stationIn a LOS area of ground stationMoving from a LOS area of ground station into a BLOS area2 Terrestrial Communication Technology Research and Development68　　　Journal of the National Institute of Information and Communications Technology Vol. 64 No. 2 (2017)