3D radar
3D radar provides for radar coverage on three dimensions unlike the more common 2D radar. While the normal 2D radar provides range and azimuth, the 3D radar provides elevation information with range and azimuth. Applications include weather forecasting, defense and surveillance.
[edit] 3D radar techniques
Steered beam radars steer a narrow beam through a scan pattern to build a 3-D picture. Examples include NEXRAD doppler weather radar (which uses a parabolic dish) and the AN/SPY-1 phased-array radar employed by the Ticonderoga class of guided missile cruisers and other ships so equipped with the Aegis Combat System.
Stacked beam radars emit and/or receive multiple beams of radio waves at two or more elevation angles. By comparing the relative strengths of the returns from each beam, the elevation of the target can be deduced. An example of a stacked beam radar is the ARSR-4.
Figure 1: Diagram of a typical 2D radar rotating cosecant squared antenna pattern
Figure 2: Diagram of a typical 3D radar, a judicial mix of vertical electronic beam steering and mechanically horizontal movement of a pencil-beam
