3D radar

3D radarprovides forradarranging and direction in three dimensions. In addition to range, the more common two-dimensional radar provides only azimuth for direction, whereas the 3D radar also provides elevation. Applications includeweather monitoring,air defense,and surveillance.

Type 984 radaronHMSVictorious,1961

The information provided by 3D radar has long been required, particularly for air defence andinterception.Interceptors must be told the altitude to climb to before making an intercept. Before the advent of single unit 3D radars, this was achieved with separate search radars (giving range and azimuth) and separateheight finding radarsthat could examine a target to determine altitude. These had little search capability, so were directed to a particular azimuth first found by the primary search radar.

Techniques

Diagram of a typical 2D radar rotatingcosecant squared antennapattern.

Diagram of a typical 3D radar, a judicious mix of vertical electronic beam steering and mechanically horizontal movement of a pencil-beam

Steered beamradars steer anarrow beamthrough a scan pattern to build a 3-D picture. Examples includeNEXRADDopplerweather radar(which uses a parabolic dish) and theAN/SPY-1passive electronically scanned arrayradar employed by theTiconderoga classofguided missile cruisersand other ships so equipped with theAegis Combat System.

Stacked beamradars 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 theAir Route Surveillance Radar.

See also

• Type 984 radar,British aircraft carriers
• AN/TPS-75US-made transportable PESA 3D air search radar
• Ghamar (3D radar)

External links

• "CEA FAR 3D Radar".Archived fromthe originalon 2004-08-13.Retrieved2004-10-31.
• "ESR 360L 3D Surveillance Radar".Archivedfrom the original on 2006-09-23.Retrieved2006-05-16.