The electromagnetic spectrum is an operational domain, just like land, sea, air, space and cyberspace. Almost every modern military capability relies on the EMS: communication, navigation, detection, weapon guidance, identification and disruption. Whoever controls the spectrum sees first, shoots first and is less easily seen.
This chapter walks through the militarily relevant part of the spectrum from low to high and links each region to its applications for detection and determining position, range and velocity. The common thread from The electromagnetic spectrum still applies: low frequencies reach far but measure coarsely; high frequencies measure finely but reach less far and are more sensitive to weather and atmosphere.