radar vs radiolocation

radar

noun
  • A method of detecting distant objects and determining their position, velocity, or other characteristics by analysis of sent radio waves (usually microwaves) reflected from their surfaces 

  • A type of system using such a method, differentiated by platform, configuration, frequency, power, and other technical attributes. 

  • An installation of such a system or of the transmitting and receiving apparatus. 

  • A superior ability to detect something. 

verb
  • To scan with radar, or as if with radar. 

radiolocation

noun
  • The detection and locating of distant objects using microwave radiation; especially radar 

  • The locating of an object that is fitted with a radio tag 

  • A location so identified 

How often have the words radar and radiolocation occurred in a corpus of books? (source: Google Ngram Viewer )