Current Location of SAR Satellite Data Utilization. Game Changer is “Realtime Connectivity”
[Professor Shirasaka x CEO Tsunemachi talk]
A SAR (Synthetic Aperture Radar) satellite that can capture the condition of the ground even in the clouds at night. Venture companies in Japan and overseas are embarking on the construction of constellations, and it is expected that they will be further utilized in the future.
What can we do with this SAR satellite? What is the bottleneck for practical use? How will our lives and satellite business change if that is resolved?
We asked Professor Shirasaka, a professor at Keio University Graduate School and co-founder of SAR satellite venture Synspective, about WARPSPACE CEO Tsunemachi.
Seikou SHIRASAKA
Completed the master’s program at the University of Tokyo (aerospace engineering) and completed the doctoral program at Keio University (system engineering). After graduating from graduate school, he engaged in space development at Mitsubishi Electric for 15 years. He participated in the development of “Stork” and so on. He works on research on innovation creation methodologies for technology-social fusion systems. Since 2008, he has been a part-time associate professor at Keio University Graduate School of SDM. He has been a full-time associate professor since 2010 and a professor since 2017. From December 2015 to March 2019, he developed the on-demand small synthetic aperture radar (SAR) satellite as the program manager of the Cabinet Office Innovative Research and Development Promotion Program (ImPACT). He set up a space venture Synspective Inc. to carry out research and education that can be implemented in society.Warpspace Co., Ltd. CEO Satoru TSUNEMACHI
His first entrepreneurship while attending University of Tsukuba (20 years old). While specializing in international investment law at graduate school, he has been involved in the launch of four companies in parallel. (One of them is Vietnam). He is mainly in charge of business strategy, branding, legal affairs, finance, etc. as a founding member / officer of IT startups. He has also participated in entrepreneurship development activities.As a Warpspace, he is an outside director from November 2016 to December 2018. In order to realize the democratization of the space industry from the context of the Internet / communication, we are making every effort to create the world’s top telecommunications carrier in space from Japan.
* Hereafter, titles are omitted
The Instantaneous Action for the First 2 Hours is the Key After Disaster Happened
Tsunemachi: First of all, could you tell us what you expect from the SAR satellite?
Shirasaka: Sure, let’s begin with the characteristics of SAR satellites. The biggest difference compared to optical satellites is that they can be observed even under clouds and can be photographed even at night when the sun is not rising. Therefore, it is compatible with disaster response where you do not know when it will occur.
Tsunemachi: Speaking of disaster response, the other day, I saw that Synspective will conduct a joint demonstration with the National Research Institute for Earth Science and Disaster Prevention (hereinafter referred to as NIED), which is conducting comprehensive research on natural disaster response.
Shirasaka: For Synspective, disaster response has been one of the areas we have been focusing on since our founding.
Speaking of disasters, it is predicted that the Nankai megathrust earthquake that will hit the entire country from Tohoku to Kyushu region will occur between 2025 and 2045. The estimated total damage is about 220 trillion yen. We are exposed to the potential for disasters that we have never experienced before.
Since satellites are the only ones that can capture the damage that is occurring over a wide area, various parties have said, “I want you to use satellite data as soon as possible in the event of a disaster.”
Synspective launched the first small SAR satellite in December 2020, so I tried to use the data immediately, but the problem of “I don’t know where to shoot” came up. SAR satellites consume a huge amount of power to shoot, so you can’t keep shooting all the time, and it’s too late to start moving after learning about a disaster in the news.
Therefore, we collaborated with the NIED, which is an expert in disaster prevention, in order to quickly obtain information and create a mechanism to move. The NIED, which has many years of experience, can predict that “this place will be dangerous next time”, so we can move toward data acquisition before a disaster occurs. As the number of satellites increases in the future, we will be able to meet further needs.
Tsunemachi: You decide the command to send to the satellite from the information that “a disaster is likely to occur”. I think that the reason why remote sensing by satellite is effective in disaster response is “responsiveness”, but what is the lead time required from the actual site?
Shirasaka: In the national project “Strategic Innovation Creation Program (commonly known as SIP)” established by the Cabinet Office for the purpose of realizing science and technology innovation, the goal is to grasp the disaster situation over a wide area within two hours after the disaster. These two hours are the approximate time it takes for the government to set up a disaster response headquarters.
After all, the initial action will change depending on how much information is available before the disaster response headquarters is established. It is necessary to improve the quality of information that can be provided there, and for that purpose, it is necessary to improve the number of satellites, the number and capacity of paths that can be downlinked, and the processing speed on the ground.
The Wall of Responsiveness Required in the Field
Tsunemachi: We have talked about disaster response so far, but what are the other use cases of SAR data that are attracting attention?
Shirasaka: The frequency of Synspective’s SAR sensor is in the X band, which is suitable for capturing artificial objects. Therefore, there is potential for use in urban development.
For example, a collapse accident. There is an image that a big hole will open, but the actual damage is not limited to that. Interference SAR analysis revealed that the surrounding land may move sideways and the surrounding buildings may bend or collapse.
<What is interference SAR analysis?>
It is a technology that can detect changes in the ground surface at the level of several centimeters from the difference between the first and second observation results.
Synspective uses this technology to provide a service that looks at vertical and horizontal ground movements and predicts areas where there is a possibility of depression.
The good thing about satellites is that it’s relatively easy to keep shooting the same area for a period of time. Also, although the survey is planned by points, it is also a point to know that the survey did not understand because the SAR satellite is looking at the surface. In the depressed area, there is a sign that something is a little wrong.
Tsunemachi: Speaking of urban development, 60 years have passed since the period of high economic miracle in Japan, and it is time for infrastructure issues to emerge. However, infrastructure maintenance is very costly.
If the SAR satellite is used well, it may be possible to detect signs and prevent major accidents even in areas where maintenance is inadequate.
Shirasaka: You’re right. It is one of our thoughts to carry out “sustainable urban development”. Infrastructure maintenance needs to be streamlined. I think that the SAR satellite can be used to propose “Let’s give priority to maintenance from bridges and roads where fluctuations are occurring”.
Furthermore, it was found that the ground movement data is of great interest to those who work at the construction site.
I received a consultation saying, “I want to know what happened today after I dug yesterday.” There seems to be a need to check if there is a problem with the part that you worked on.
Tsunemachi: The SAR satellite has the advantage of capturing the physical movement of something. You can also see use cases for ocean surveillance.
Shirasaka: That’s right. Ocean surveillance is exactly the case where responsiveness is required. Especially in Asia, there are still many pirate ships in operation, and there are countries that are struggling, and there will be needs. However, even if an illegal fishing boat or suspicious boat is detected, it will move, so it would be a problem if you were informed that you were here two hours ago. It is necessary to increase the immediacy of providing information as soon as possible.
The Role of Terrestrial Broadcasting and Satellites that Changes with Constant Connection
Tsunemachi: There are many things that earth observation satellites can contribute to the world, such as disaster prevention measures, monitoring for infrastructure maintenance, urban development, and detection of illegal activities. I think that “always-on connectivity” is a keyword that realizes “immediateness” required to put each case into practical use.
Shirasaka: If we can perform on-board processing in orbit, we can increase the amount of useful information that can be downlinked as a result. In addition, if data processing on the ground is no longer necessary, it may be possible for users who need the data to directly downlink the data.
However, if a constant connection is realized, the time from shooting to analyzing the data and delivering it to the user should be shorter than the onboard processing. Since we are expecting high-capacity and high-speed communication by optical communication, we are also wondering how much on-board processing will be required.
Tsunemachi: If instant communication is always possible, the way of onboard processing may change.
Shirasaka: That’s right. Nowadays, the timing and capacity of communication between satellites and the ground are limited, and satellites are designed accordingly. The role of satellites and terrestrial broadcasting may change significantly if there are constant connections and the restrictions are removed. For example, the automobile industry has been innovating in that way, and I think the same thing can happen to satellites.
Besides, if the data can be delivered to the ground sooner, the demand will increase and the number of satellites will increase steadily. Then, the types of sensors mounted on the satellite will be diversified, and more will be seen from space.
Tsunemachi: That’s exactly what we at Warp Space are aiming for. If you design your satellite on the premise of an environment where you can always communicate, you should be able to do more. I would like to make a game change together with earth observation satellite operators and telecommunications carriers.
