I was involved with a job using a Fiber based perimeter fence intrusion detection system back when this was a new thing and the sensitivity was its main proble

I was involved with a job using a Fiber based perimeter fence intrusion detection system back when this was a new thing and the sensitivity was its main problem due to false positives. You needed to rezone and adjust thresholds in zones based on wind direction etc. Still it is a great tech & nice to see it applied at this scale for pure science. BTW my understanding is the idea was first commercialized by oil and gas to discover real-time conditions down a drilling well head.