China tested a handheld submarine detector. It tracked a subway train underground

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Chinese scientists developed a handheld quantum magnetometer designed to detect submarines and demonstrated it by tracking a subway train underground. The device is compact and energy efficient, representing a notable advancement in magnetic sensing technology.

🌐 Location: HK — Sources: 2 — First seen: 2026-09-25 — Last seen: 2026-09-26

China quantum magnetometer submarine detector technology magnetic sensing