The University of Tokyo and NTT have jointly developed millimeter-wave RFID that functions as a beacon that conveys information about the surrounding environment.
By using RFID tags that can be read using millimeter waves, which are less affected by weather than visible light, the navigation accuracy of drones will be improved in conditions of poor visibility due to darkness or bad weather.
In the future, they plan to use this technology to build a sensor network that will continue to measure the environment from the sky in all weather conditions, even in unexplored areas such as ocean areas and disaster-stricken areas, where it is difficult to grasp information, thereby improving weather prediction and disaster response. 
NTT Space, Environment and Energy Laboratories is promoting the development of weather observation technology over ocean areas in order to improve the accuracy of future predictions of the global environment. Specifically, they are considering weather observation technology using drones.
For example, when taking off a drone from a ship to observe the atmosphere at a height of 500 meters or more, it is important to coordinate operations between the ship and the drone and guide the drone.
Previously, QR code signs were used to guide drone landings. However, the signs do not work in the dark, rain, or fog.
Therefore, there was a need for signs that could be read even in poor visibility.
　　
Various technologies have been studied for tags that can be read using radio waves called millimeter waves, which are less affected by weather, but it has been difficult to create millimeter-wave RFID tags that can be read from a wide range in the air. Against this backdrop, the two companies developed a millimeter-wave RFID tag that functions as a beacon that conveys information about the surrounding environment. This is expected to improve drone navigation accuracy under poor visibility.
By establishing design technology for corner reflector type chipless RFID tags that can be read from a wide range and radar signal analysis technology that uses eigenvalue analysis to enable highly accurate reading even in noisy environments, they have achieved all-weather, battery-free, and wide-range reading. A millimeter wave RFID tag has been realized.
　　
In the future, the company will use millimeter-wave RFID tag guidance technology to enable autonomous operation of drones in harsh environments such as darkness and bad weather, promoting disaster response and the advancement of ocean observation. Since this technology can be applied to things such as understanding the amount of cargo carried by trucks, they are also exploring partnerships with the logistics industry.
Ultimately, they will build an innovative aerial sensor network consisting of not only drones but also a variety of IoT sensors, and create an optimized system from hardware to software to grasp information in unexplored areas. The idea is to strengthen the 4D digital infrastructure.