View source for 3D radar

{{Short description|Radar ranging and direction in three dimensions}}
[[File:AD-6 of VA-52 landing on HMS Victorious (R38) 1961.jpg|thumb|[[Type 984 radar]] on {{HMS|Victorious|R38|6}}, 1961]]
'''3D radar''' provides for [[radar]] ranging 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 include [[weather radar|weather monitoring]], [[air defense]], and surveillance.

The information provided by 3D radar has long been required, particularly for air defence and [[Ground-controlled interception|interception]]. 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 separate [[height finding radar]]s that 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 ==
[[File:2d-radarp.jpg|thumb|left|Diagram of a typical 2D radar rotating [[cosecant squared antenna]] pattern.]]
[[File:3d-radarp.jpg|thumb|Diagram of a typical 3D radar, a judicious mix of vertical electronic beam steering and mechanically horizontal movement of a pencil-beam]]
'''Steered beam''' radars steer a [[narrow beam]] through a scan pattern to build a 3-D picture. Examples include [[NEXRAD]] [[Pulse-Doppler radar|Doppler]] [[weather radar]] (which uses a parabolic dish) and the [[AN/SPY-1]] [[passive electronically scanned array]] radar employed by the [[Ticonderoga-class cruiser|Ticonderoga class]] of [[guided missile cruiser]]s 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 [[Air Route Surveillance Radar]].

== See also ==
* [[Type 984 radar]], British aircraft carriers
* [[AN/TPS-75]] US-made transportable PESA 3D air search radar
* [[Ghamar (3D radar)]]

==External links==
*{{cite web|url=http://www.cea.com.au/products/phasedarray/ceafar.html |title=CEA FAR 3D Radar |access-date=2004-10-31 |url-status=dead |archive-url=https://web.archive.org/web/20040813131811/http://www.cea.com.au/products/phasedarray/ceafar.html |archive-date=2004-08-13 }}
*{{cite web|url=https://www.reutechradar.com/products/3d-surveillance.htm|title=ESR 360L 3D Surveillance Radar |access-date=2006-05-16 |url-status=live |archive-url=https://web.archive.org/web/20060923173902/http://www.rrs.co.za/products/3d-surveillance.htm |archive-date=2006-09-23 }}

[[Category:Radar]]