• SOTEN is a Japan-made, high-security drone widely used for infrastructure inspection, disaster response, surveying, and monitoring applications.
• As part of a key strategic initiative under its mid-term management plan, “Drone evolution with advanced technologies,” ACSL continues to implement functional improvements that reflect customer feedback.
• The latest update improves flight safety in high magnetic field environments and enhances operability through upgrades to autonomous flight functions and the user interface.

ACSL Ltd. (“ACSL”) hereby announces the release of a regular software update for its secure, Japan-made small aerial photography drone, SOTEN.
Since receiving orders in December 2021, SOTEN has been deployed across a wide range of mission-critical fields that support social infrastructure, including infrastructure inspection, disaster response, surveying, and monitoring operations. ACSL continuously enhances SOTEN’s functionality through regular updates released several times a year, incorporating feedback directly from customers who operate the drone in real-world field environments.
The latest update focuses on improving flight safety when operating in environments susceptible to magnetic interference—such as near power transmission lines, steel towers, and construction sites—as well as enhancing operability through improvements to autonomous flight functions and the control interface.

■Key Enhancements in This Update
Enhancement 1: Safer and More Stable Flight in High Magnetic Field Environments
Strong magnetic fields are commonly generated near power transmission lines and steel towers, while construction sites may also cause magnetic disturbances due to steel plates installed on the ground. These conditions can lead to unstable flight behavior.
In response to requests from customers actively operating SOTEN in such environments, this update strengthens the magnetic calibration functionality to better handle magnetic disturbances.
During planned flights in AUTO mode, if magnetic deviation is detected, the aircraft automatically performs in-flight calibration and continues the mission. This minimizes flight instability caused by magnetic interference, enabling safe and uninterrupted inspection operations.
In addition, a new feature has been added for other flight modes. When magnetic deviation is detected, a warning message is displayed, allowing the operator to perform in-flight calibration by rotating the aircraft 360 degrees in the air. This enables immediate on-site adjustment without landing, significantly improving operational flexibility.
Furthermore, the judgment logic for pre-flight magnetic calibration has been improved, allowing the process to be completed more quickly and smoothly, thereby reducing preparation time and operator workload.
Through these enhancements, SOTEN delivers improved flight safety and reliability even in high magnetic field environments.

Enhancement 2: Smarter Autonomous Flight Capabilities
A new function has been added to the automatic Go-Home feature. When activated, the system automatically calculates the shortest return route while taking into account no-fly areas preconfigured by the operator, and safely navigates around them.
This reduces the need for operator intervention during return flights and provides greater reliability and confidence during emergencies or long-distance missions.

Enhancement 3: Improved Usability to Support Field Operations
In addition to safety and operability enhancements, ACSL has implemented UI improvements to increase on-site work efficiency.
・FPV Grid Overlay Display
This feature makes it easier to understand positional relationships between the drone and inspection targets, enabling more precise inspection of power lines, structures, and other assets. The enhancement reflects feedback from the U.S. market, where inspection use cases are particularly prevalent.

・UTM Coordinate Display Support
Support for UTM coordinate display—commonly used in defense and security fields—has been added, facilitating easier sharing of location information across teams and organizations.

■About SOTEN
SOTEN was developed under the “Development of basic technology for safe and secure drones” project funded by the New Energy and Industrial Technology Development Organization (NEDO), a Japanese national research and development agency. The drone incorporates security measures based on ISO/IEC 15408, an international computer security standard, ensuring protection against data leakage, data extraction, and unauthorized aircraft takeover.
As a secure, Japan-made drone, SOTEN is already being utilized in fields such as infrastructure inspection, disaster response, and surveying.

* For more detailed product information, please visit the SOTEN page on the ACSL product website.
https://product.acsl.co.jp/product/post-369/

ACSL is promoting key strategic initiatives under its mid-term management plan, “ACSL Accelerate FY26,” aiming to become “a trusted global manufacturer supporting safety and security.”
Efforts such as the latest updates to SOTEN—incorporating feedback from actual operational sites to continuously enhance product safety and operational performance—are being carried out under the key strategy of “Drone evolution with advanced technologies.” Through such product evolution, ACSL further strengthens high reliability and on-site adaptability, thereby building a foundation that supports the company’s mid- to long-term growth strategy.
ACSL will continue to contribute to improved safety and efficiency at critical sites supporting society—including infrastructure inspection and disaster response—through customer-centric product enhancements.

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