The radar needs 3 pieces of information to determine the location of a target.

The first piece of information is the angle of the radar beam with respect to north; called the "azimuth angle".

The second is the angle of the beam with respect to the ground; called the "elevation angle".

The third piece of information needed is the distance (D) from radar to target.

Distance is determined by measuring the time it takes for the pulse to make a round trip from the radar to the target and back using the relation distance = (time) * (velocity). The velocity is the speed of light, the speed at which the pulse travels (c). Since the pulse has to travel to the target and back, the total distance is 2D. If t is the time it takes, then 2D = ct or D = ct/2. Using the calculated distance, azimuth angle and elevation angle, the exact location of the target can be determined.

clear air returns

Terms for using data resources. CD-ROM available. Credits and Acknowledgments for WW2010. Department of Atmospheric Sciences (DAS) at the University of Illinois at Urbana-Champaign.

scanning modes