Search results
Results From The WOW.Com Content Network
For most antennas the boresight is the axis of symmetry of the antenna. For example, for axial-fed dish antennas, the antenna boresight is the axis of symmetry of the parabolic dish, and the antenna radiation pattern (the main lobe) is symmetrical about the boresight axis. Most antennas boresight axis is fixed by their shape and cannot be changed.
The half-power point is the angle off boresight at which the antenna gain first falls to half power (approximately −3 dB) [a] from the peak. The angle between the −3 dB points is known as the half-power beam width (or simply beam width). [4] Beamwidth is usually but not always expressed in degrees and for the horizontal plane.
These axially symmetric antennas have radiation patterns with a similar symmetry, called omnidirectional patterns; they radiate equal power in all directions perpendicular to the antenna, with the power varying only with the angle to the axis, dropping off to zero on the antenna's axis. This illustrates the general principle that if the shape ...
Conical scanning concept. The radar beam is rotated in a small circle around the "boresight" axis, which is pointed at the target. Conical scanning is a system used in early radar units to improve their accuracy, as well as making it easier to steer the antenna properly to point at a target.
Consider, for example, a two element array spaced apart by one-half the wavelength of an incoming RF wave. If a wave is incident upon the array at boresight, it will arrive at each antenna simultaneously. This will yield 0° phase-difference measured between the two antenna elements, equivalent to a 0° AoA.
The R-73 is an infrared homing (heat-seeking) missile with a sensitive, cryogenic cooled seeker with a substantial "off-boresight" capability: the seeker can detect targets up to 40° off the missile's centerline. [7] It can be targeted by a helmet-mounted sight (HMS) allowing pilots to designate targets by looking at them. Minimum engagement ...
Boresight may refer to: Antenna boresight, the optical axis of a directional antenna; Boresight (firearm), adjustments made to an optical sight, to align the barrel of a firearm with the sights; Boresight point, also known as gun harmonisation, the alignment of weapons in an aircraft; Project Boresight, a US radio direction finding system
They are important for military warning systems and target location. [18] They are especially useful in naval systems because of the wide angular coverage that can be obtained. [ 19 ] Another feature that makes Butler matrices attractive for military applications is their speed over mechanical scanning systems.