a method, system, or technique for using beam, reflected, and timed electromagnetic radiation to detect, locate, and track objects, to measure distance (altitude), and to acquire terrain imagery —note 1. radar is an acronym from RAdio Detection And Ranging —note 2. in remote sensing, radar refers to active microwave systems (from about 1 GHz to 100 GHz; the majority of current instruments operate below 10 GHz)This definition last updated 08/11/2008