Definition of radar

​RADAR is an acronym meaning: RAdio Detection And Ranging. 
 
It is a device which measures not only the time it takes for a pulsed signal to be reflected back from an appropriate object, but also determines its bearing relative to your position. 
 
Once the time and bearing are measured, these targets or echoes are calculated and displayed on your radar display. 
 
This will give you a birds eye view of where other targets are relative to you, even when you can not see them with your eyes due to low visibility.