e/Kopac passive sensor

Information
has gloss	eng: Kopáč (the word means "digger" in Czech) was an early electronic warfare support measures (ESM) system developed in Czechoslovakia in the early 1960's that used measurements of time difference of arrival (TDOA) of pulses at three sites to accurately detect and track airborne emitters. The system used the principle of multilateration and was capable of simultaneously manually tracking up to six targets. It was first deployed in 1963 and was also known by its serial number, PRP-1. The initials PRP come from the Czech "Přesný Radiotechnický Pátrač", meaning "Accurate Radiotechnical Locator", the name comes from "Korelační pátrač", meaning "Correlation Locator".
lexicalization	eng: Kopac passive sensor
lexicalization	eng: Kopáč passive sensor
instance of	c/Radiofrequency receivers