Utilize satellite sar technology for disaster prevention and mitigation to realize safe and secure urban development
Efforts to minimize the damage caused by natural disasters, which are becoming more severe year by year, are progressing in various fields. “ASNARO-2” launched by NEC in 2018 is also an artificial satellite that is expected to be used for disaster countermeasures. Takakazu Ishii, Senior Expert, Radio Waves and Guidance Division, NEC, talked about the technology called "SAR", which generates images of the ground using satellite-mounted radar, and its potential.
SAR technology attracting attention in the field of disaster prevention and mitigation
In recent years, natural disasters such as typhoons and heavy rains caused by climate change occur almost every year, and the possibility of a large-scale earthquake occurring in the future is often pointed out. Utilization of data is needed to minimize damage and save as many lives as possible.
In addition to weather information, data that serves as the basis for evacuation orders and recommendations by mayors of municipalities includes data that indicates the risk of river flooding and landslide disasters, but some of this information is collected through visual inspection by the staff in charge. Not a few. However, post-disaster site surveys are fraught with great danger, and there may be cases in which access to the site is not possible due to disruptions to roads, etc. One of the ways to deal with these issues is the use of artificial satellites.
“What we are currently working on is disaster prevention and mitigation using a technology called SAR,” explains Takakazu Ishii, Senior Expert, Radio Waves and Induction Division, NEC.
Successful launch of Japan's first commercial SAR technology satellite
SAR technology is a technology that was originally developed in the 1960s for the purpose of ocean surveillance. NEC began its research in the 1970s, and in 1980, succeeded in image reproduction processing of SAR technology data for the first time in Japan. Since then, the technology has been provided to JAXA (Japan Aerospace Exploration Agency) and others. In 2018, it launched Japan's first commercial SAR technology satellite "ASNARO-2", and is the only one in Japan to have a one-stop system for satellite operation, image generation, and image analysis.
“The SAR technology satellite orbits the earth in a north-south direction at a speed of about 100 minutes, and returns to the exact same position in about two weeks. , it is possible to observe any region on the earth under exactly the same conditions in about two weeks.So far, in addition to ocean monitoring, forest management, resource exploration, civil engineering support, maintenance and management of infrastructure such as power plants and bridges. Since it uses microwaves, unlike optical observations, SAR's great strength is that it can see through clouds and volcanic plumes regardless of day or night. Currently, we are considering a joint project to observe ground deformation associated with the Russian natural gas project, and we are also collaborating with other overseas consulting companies.”
ASNARO-2 has performed remarkably well in the two years since its launch. In Japan, emergency observations of landslides caused by the Hokkaido Eastern Iburi Earthquake that occurred in September 2018, observations of Mount Shinmoedake in Kyushu, which also erupted in 2018, and damage observations of Typhoon No. , and the observation of the Kuma River in Kumamoto Prefecture in 2020. While combining with other data, we are able to grasp accurate information from images, and some images captured by emergency observations are used by users in disaster areas through disaster prevention organizations.
Utilizing data accumulation during normal times for disaster prevention measures
When a disaster occurs, it is possible to visualize topographical changes, river flooding, coastline changes, etc. by referring to the most recent past SAR technology images and looking at the difference from the current situation. SAR technology images can also be used to check the status of damage to highways and railways. On the other hand, there are also challenges.
"In the event of a disaster, if you want to refer to past SA technology images and see the difference from the current situation, you will need SAR technology images captured under exactly the same conditions. The SAR technology satellite will reach the exact same sky above the location to be observed. The time it takes to generate images is a major issue for all stakeholders involved in SAR technology right now, even if the timing is right, it can take 2 to 3 days, and if image analysis is included, it can take up to 5 days. It is often said that there is a “72-hour wall” in disasters, which means that it takes 72 hours for the life of a missing person to be saved.In the current situation, it is difficult to overcome that wall. increase"
What Ishii presents is another possibility of using SAR.
“At the moment, the most effective way to use SAR technology is to use data accumulated during normal times for disaster prevention measures,” says Ishii. "By analyzing high-precision time-series changes from SAR technology images, it is possible to predict areas that are likely to suffer major damage in the event of a disaster, which cannot be obtained by (ground) visual surveys. , and hazard maps and evacuation maps to simulate disasters and minimize the scale of damage.We are currently drawing up such a vision.”
Image analysis technology is one of NEC's strongest areas.
"In addition to the basic technology of image analysis, it is possible to further improve the accuracy of analysis by utilizing AI. NEC's proprietary image analysis technology was sponsored by the economic newspaper Fuji Sankei Business i, and the Ministry of Education, Culture, Sports, Science and Technology We won the 2019 Sankei Shimbun Award at the Advanced Technology Awards sponsored by the Ministry of Economy, Trade and Industry .”
According to Ishii, SAR-based image generation and its analysis are also fundamental technologies for creating safe and secure cities.
“We believe that SAR technology is an indispensable technology for making smart cities built using network technology, IoT, AI, etc. more resilient to disasters. In cooperation with the project department, we are creating a path to utilize SAR technology in community development.”
Four co-creations for full-scale utilization of SAR technology
Efforts for disaster prevention and mitigation using satellites cannot of course be promoted by NEC alone. Currently, four co-creations related to SAR technology are underway.
The first is co-creation with energy companies and telecommunications companies. The first prospect of co-creation is to have these companies use SAR technology in their business continuity plans (BCPs) and connect it to the BCP of the entire region.
The second is co-creation with venture companies. From 2025 to 2030, many domestic and foreign venture companies are planning to launch small SAR technology satellites for disaster prevention purposes. The number is expected to range from 30 to 100.
“By increasing the number of satellites, the problem of non-real-time image generation will be resolved. If we have 100 SAR technology satellites, we should be able to reduce the time from image generation to analysis to about half a day.”
The third is co-creation with a company that specializes in data platforms. Combining SAR technology images with meteorological data, geological data, etc., will become a more powerful solution for disaster prevention and mitigation. In order to create such a common data infrastructure, cooperation with data platform companies is essential.
The fourth is co-creation within the group. Ishii says that he hopes to further increase the value of SAR technology through collaboration with Japan Earth Observation Satellite Service Co., Ltd., which operates ASNARO-2 and sells images, and domestic and overseas group companies engaged in smart city-related businesses.
“Since 2014, we have been working on business creation using satellites.In order to launch a new business, we have to overcome technical hurdles, business model hurdles, and internal organizational hurdles one by one. No. It's not an easy task, but if we give up, all our efforts will be in vain.We want many companies and local governments in Japan and overseas to use satellite SAR technology. In addition, through extensive co-creation, we aim to make this technology a foundation that protects the safety and security of society, and we would like to continue our efforts toward that goal.
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