Distance-determination

 

 

The distance is determined from the running time of the high-frequency transmitted signal and the propagation speed C₀. The actual range of a target from the radar is known as slant range. Slant range is the line of sight distance between the radar and the object illuminated while ground range is the horizontal distance between the emitter and its target and its calculation requires knowledge of the target's elevation. At this this one, however, to and way back must taken into account. Therefore the following formula arises for the slant range:

R =  c0 · t 2

C0 = speed of light = 3•108 m/s t = measured time [s] R = slant range [m]

The Distances are expressed in kilometers or nautical miles.

Derivation of the equation

Range is the distance from the radar site to the target measured along the line of sight.

v =  s in  m t s v = speed s = range t = time

Figure 1: principle of radar

v =  2·R in  m t s

The factor of two in the formula comes from the observation that the radar pulse must travel to the target and back before detection, or twice the range.

 

R =  C0·t in [m] 2

Where C0= 3 x 108 m/s, is the speed of light at which all electromagnetic waves propagate.

 

If the respective running time t is known then can be calculated the distance R with help of this equation between a target and the radar set.