EPR of a drone?

[netstruggler]

Originally Posted by Jooyandeh

Salaam
I was reading an article about Lancet UAVs. Somewhere in the article, it says:

I wonder if EPR here refers to Electron Spin Reseonance or Engine Pressure Rate? Since the above-said Lancets don't have jet engines, I thought it latter could not have been intended here.

Thanks in advance for your help.

This lot, Millimetre Wave and EPR Group Drone Detection

call it Electron Paramagnetic Resonance