>long-range quantum magnetometry
but this would mean that someone is cataloging each persons signature ahead of time, that seems unrealistic.
The relatively barren landscape made for “an ideal first operational use” of Ghost Murmur, the first source said.
“The name is deliberate. ‘Murmur’ is a clinical term for a heart rhythm. ‘Ghost’ refers to finding someone who, for all practical purposes, has disappeared,” the source said.
https://nypost.com/2026/04/07/us-news/ghost-murmur-a-never-used-secret-tool-deployed-to-find-lost-airman-in-iran-in-daring-mission/
so possibly showing all human heartbeats, or human presence in the barren landscape