【SPECIAL INTERVIEW】Dr. Takashi Tadatsu × W.S.P / The Birth of the "JIKAI" Magnetic Field Sensor
The remote magnetic field sensor "JIKAI edge AI SENSOR" (JIKAI) detects the presence of magnetic fields and measures their strength and direction. Boasting performance far surpassing that of conventional magnetic field sensors and integrating AI analysis of search results, JIKAI extends its potential applications to landmine removal, underwater surveys, and even space exploration. In this interview, we spoke with Yasumasa Ichikawa, CTO of World Scan Project (W.S.P), and Dr. Takashi Tadatsu, the lead developer, about the trajectory of developing JIKAI and their vision for its future.
The Significant Differences from Conventional Magnetic Field Sensors
Ichikawa：The World Scan Project (W.S.P) is developing the next generation of magnetic field sensors. To explain the specific type of sensor we are working on, I’ll let DDr. Tadatsu provide the details.
Tadatsu：Typically, magnetic field sensors that use solid materials cannot align the center of the three axes (X, Y, and Z). Therefore, we are working on the development of the Origin-Shared 3D Magnetometer (JIKAI), which aligns the center of all three axes to a single point.
Ichikawa：The Origin-Shared 3D Magnetometer (JIKAI) can detect metal buried underground or underwater with high precision, making it a crucial tool in archaeological surveys of ruins and underwater explorations of shipwrecks conducted by W.S.P. In such investigations, conventional magnetometers such as optical pumping or fluxgate types have been used. How is JIKAI different from these magnetometers?
Examples of investigations using JIKAI
Tadatsu： First of all, optical pumping is highly sensitive and is used in various places, such as the Ministry of Defense. However, it has the drawback of being able to measure the strength of the magnetic field but not its direction. Additionally, because it lacks sensitivity to magnetic fields oriented in specific directions, it is not suitable for exploration purposes.
Tadatsu：Fluxgate magnetometers are similar to JIKAI, but there is a significant difference: the magnetic material in a fluxgate magnetometer is solid, whereas the magnetic material in JIKAI is liquid.
Ichikawa：The magnetic material forms the core of the magnetic field sensor, and the sensor is created by winding a coil around this magnetic core.
Tadatsu：Exactly. JIKAI uses a liquid (Ferrofluid) as its core magnetic material, which has the advantage of not becoming magnetized.
Ichikawa：Ferrofluid is liquid, but it possesses magnetic properties, so it fluidly attaches to magnets. It’s fascinating, isn’t it?
Tadatsu：Ordinary metals become magnets themselves once they attach to a magnet, which is due to a process called "magnetization"—applying a strong external magnetic field to induce magnetism in a material. You've probably seen paper clips becoming magnetized and sticking together, right? If magnetization occurs within a magnetic field sensor, it can distort the sensor’s characteristics. However, ferrofluid is less prone to magnetization.
Ichikawa：For example, if you attach a magnet to a fluxgate sensor like this, it will break.
A New Technology That Breaks Conventional Wisdom
Tadatsu：The reason why ferrofluid, despite its advantages, is not commonly used is that its magnetic permeability is much lower compared to solid magnetic materials like permalloy. Magnetic permeability represents how easily a material can become magnetized, with permalloy having a permeability of around 180,000, whereas ferrofluid has a permeability of about 10. This shows that ferrofluid has relatively low magnetic sensitivity.
Tadatsu：Due to its low magnetic permeability, conventional wisdom has held that ferrofluid is not suitable for use in sensors. However, we conducted numerous experiments to leverage ferrofluid's advantage of not becoming magnetized and ultimately developed a highly sensitive detection method. This method, recognized as a new technology, is now patented by our company.
Ichikawa：Fluxgate sensors are affected by external magnetic fields like geomagnetism, which causes a shift from the origin of the magnetic hysteresis loop when measuring magnetic fields. On the other hand, JIKAI has no such shift, allowing for highly reliable measurement results.
Ichikawa：When mounting a magnetic field sensor on a drone, there are concerns that the fluxgate sensor could produce inaccurate readings due to noise from sources like the motors, which generate strong magnetic fields.
Tadatsu：That's true. Since strong magnets are used in drone motors, fluxgate magnetic field sensors have been designed to avoid magnetization. However, when the power is off, these features do not function, which eventually leads to inaccurate readings. But JIKAI does not become magnetized in the first place, so it remains accurate no matter what.
The Potential Unlocked by JIKAI: Beyond Earth, into Space
Ichikawa：JIKAI is highly durable, making it a promising tool for deep-sea surveys and space exploration.
Tadatsu：Yes. For example, even if we wanted to take a magnetic field sensor to Mars, we don’t know how strong the magnetic fields there might be. There are predictions, but no one has measured them. If unexpectedly strong magnetic fields were present on Mars, conventional magnetic field sensors might become unusable. In contrast, JIKAI, which uses ferrofluid, would return to its original state after being removed from such an environment, making it highly reliable.
Ichikawa：Even if we take a fluxgate magnetic field sensor into space, if the readings become inaccurate, it lacks reliability, doesn't it? In that case, wouldn't it be better to use a more reliable sensor for exploration?
Tadatsu：You're right. We are also conducting joint research with JAXA, but both JAXA and NASA currently use fluxgate magnetic field sensors. In space exploration, magnetic field sensors from different manufacturers are employed to ensure the reliability of measurement results, but the inherent shortcomings of the fluxgate cannot be fully mitigated.
Tadatsu：That’s why sensors like JIKAI, which operate on a different principle than fluxgate sensors, are also used to compare measurement results. This approach is being adopted in the field of planetary and space science, where exploration ventures into the unknown.
in the field of planetary and space science
Ichikawa：Relying on just one sensor is unsettling. W.S.P is also considering expanding into space exploration, and we want to address these risks as we move forward.
From Mine Removal to Shipwreck Investigation
Ichikawa：Here we have the underwater 3D scanning robot "MURAKUMO," developed by W.S.P. It’s designed for 3D scanning of underwater archaeological sites and creating millimeter-precision 3D models, and we've adjusted part of it to incorporate JIKAI.
Ichikawa：Magnetic field sensors are invaluable underwater, with applications ranging from exploring metal resources and shipwrecks to mine detection, making them essential in various investigative activities.
Ichikawa：Fluxgate magnetic field sensors are used in smartphones and cars as well. If our sensors were to be applied in such areas, we would be delighted.
Tadatsu：As we are involved in research and development, being the best in the world is our priority. We aim to create a globally leading product by comparing it against the top-tier sensors from other companies.
Ichikawa：We will continue to make updates and strive to create high-performance, exciting products that can stand out against the competition. Thank you very much for today.
The innovative remote magnetic field sensor, "JIKAI edge AI SENSOR," far surpasses the performance of conventional magnetic field sensors. As it sets new standards for exploration, the World Scan Project (W.S.P) continues to challenge unknown areas using this sensor. If you're interested, please follow our activities and support us.
Watch this video to learn more about the JIKAI edge AI SENSOR.