Look-down/shoot-down is a capability a radar system is said to possess if it is able to detect, track and lock a target moving below the horizon as seen by the radar. Look-down/shoot-down capability is an essential feature of modern airborne military radar systems.
Radar waves cannot penetrate solid objects – they are reflected by solids – and the surface of the earth is no exception. Because the earth is curved, a ground-based radar can only detect an aircraft once it has cleared the horizon and is no longer hidden behind the earth. Hence a high-flying aircraft will be detected by a ground radar before a low-flying aircraft. To avoid detection, many military aircraft and missiles use very low flight profiles, a technique called terrain masking. Many modern weapons like
cruise missilesuse this tactic, making their long-range detection by ground-based radar difficult. Helicopters and strike aircraft flying very low to achieve the same effect are said to have a nap of the earthflight profile.
To detect low-flying objects, a radar must be located above them, with a line of sight to the intruder. This can be achieved to a limited degree by locating the radar system on top of a hill, or on top of tall masts (as with ships). However, the only long-range solution is to mount a radar on an aircraft flying above the intruders.
The technical challenge encountered is caused by the mass of radar returns that result from pointing a radar at the ground. The solid ground and all the objects on it reflect the radar waves, and are picked up by the radar creating confusing
clutteron the radar screen. It is difficult or impossible to separate the radar image of the low-flying intruding aircraft from the general ground clutter.
Look-down/shoot-down radars have been enhanced with electronic programmes that process the radar image and search for moving objects, which are detected by looking for
Doppler shifts in the radar return. The radar removes all static and slow moving objects (e.g. the ground, buildings, automobiles) from the display, and shows only moving objects. Since the radar is linked to the aircraft's fire control system, it can provide targeting information to weapons once it has detected a moving object.
Look-down/shoot-down radars provide a combat aircraft with the ability to engage targets flying below them. This is highly desirable, as it allows an aircraft to detect and attack targets whilst maintaining the tactically advantageous position conferred by superior altitude.
Most modern fighter aircraft possess look-down/shoot-down capable radars.
However, this using of the Doppler Effect to separate moving fighters gives the target a way of eluding the searching radar. If the target aircraft flies
perpendicularto the radar beam, its speed relative to the attacker become the same as the ground, and there is potential for the system to lose it. This is known as "beaming" because it is maneuvering so that the radar is placed in the aircraft's beam (which is the position perpendicular to the aircraft's flight direction).
Wikimedia Foundation. 2010.
Look at other dictionaries:
Look-Down-Fähigkeit — Das AN/APG 77 der F 22 Raptor Die Tiefsichtfähigkeit oder englisch Look down/shoot down Capability (Fähigkeit, nach unten zu sehen) bezeichnet die Fähigkeit eines aktiven Radars in Militärflugzeugen, Kontakte unterhalb der eigenen Flughöhe zu… … Deutsch Wikipedia
look-down, shoot-down — adjective Describing a phased array radar powerful enough to pick aircraft out of ground clutter from high altitude … Wiktionary
shoot*/*/*/ — [ʃuːt] (past tense and past participle shot [ʃɒt] ) verb I 1) [I/T] to fire a gun We were ordered not to shoot until he gave the signal.[/ex] They were shooting at bottles on a wall.[/ex] Armed officers had instructions to shoot the kidnapper on… … Dictionary for writing and speaking English
Down (Jay Sean song) — Down Single by Jay Sean featuring Lil Wayne from the album All or Nothing … Wikipedia
Shoot (magazine) — Shoot, or Shoot Monthly, was a football magazine published in the UK by IPC Media. After nearly 40 years, it ceased publication at the end of June 2008. [ [http://www.brandrepublic.com/News/817286/Shoot closes weekly bid fails/ Shoot closes as… … Wikipedia
shoot — shoot1 W2S2 [ʃu:t] v past tense and past participle shot [ʃɔt US ʃa:t] ▬▬▬▬▬▬▬ 1¦(kill/injure)¦ 2¦(fire a gun etc)¦ 3¦(birds/animals)¦ 4¦(move quickly)¦ 5¦(try to score)¦ 6¦(look at somebody)¦ 7¦(photograph/film)¦ 8¦(pain)¦ 9 … Dictionary of contemporary English
shoot — 1 /Su:t/ verb past tense and past participle shot /St/ GUNS/WEAPONS 1 KILL/INJURE (T) to deliberately kill or injure someone using a gun: Lincoln was shot while watching a play in Ford s Theater. | shoot sb in the leg/head etc: He had been shot… … Longman dictionary of contemporary English
Shoot 'em up — For the film genre, see Western (genre). For the 2007 action film, see Shoot Em Up … Wikipedia
shoot — [[t]ʃu͟ːt[/t]] ♦♦ shoots, shooting, shot 1) VERB If someone shoots a person or an animal, they kill them or injure them by firing a bullet or arrow at them. [V n] The police had orders to shoot anyone who attacked them... [V n] Namibian law… … English dictionary
shoot — shoot1 [ ʃut ] (past tense and past participle shot [ ʃat ] ) verb *** ▸ 1 fire gun ▸ 2 in sports ▸ 3 move suddenly & quickly ▸ 4 take photographs etc. ▸ 5 put drug in body ▸ + PHRASES 1. ) intransitive or transitive to fire a gun: We were… … Usage of the words and phrases in modern English