# Phase-Comparison Monopulse

Phase-Comparison Monopulse

Phase-interferometry describes a technique that can be used in radar and direction finding applications to accurately estimate the direction of arrival of a signal from the phase difference of the signal measured on two (or more) separated antennas.

Mathematics

Assume two antenna separated by a distance "d", with a wavefront incident at an angle θ, then the extra path the signal must travel between Antenna 1 and Antenna 2 (see figure) results in a phase difference, ΔΦ, between the two antennas. This can be used to calculate the direction of arrival using::$heta = sin^\left\{-1\right\} left\left( frac\left\{lambda Delta Phi\right\}\left\{2 pi d\right\} ight\right)$where λ is the signal's wavelength.

For unambiguous results, the antennas should be spaced half a wavelength apart, or less. However, this can result in significant mutual coupling between elements, which means that each antenna's phase measurement will be corrupted by the other's. The approach assumes that the phase centres of the antennas are exactly known. With more complex antenna structures (such as the log-periodic antenna) the effects of mutual coupling can make the phase centre locations unknown. In this case, calibration or electromagnetic modeling may be required.

The ability to accurately measure a signal's phase depends on the signal-to-noise ratio (SNR), and hence the accuracy of this technique is dependent on the SNR.

ee also

* Very Long Baseline Interferometry
* Amplitude monopulse

Wikimedia Foundation. 2010.

Поможем написать курсовую

### Look at other dictionaries:

• Amplitude-Comparison Monopulse — Amplitude monopulse direction finding refers to a common technique employed in radar systems to improve the accuracy with which the direction of arrival of a pulse can be estimated. Approach Two overlapping antenna beams are formed, which are… …   Wikipedia

• Monopulse radar — is an adaptation of conical scanning radar which sends additional information in the radar signal in order to avoid problems caused by rapid changes in signal strength. The system also makes jamming more difficult. Most radars designed since the… …   Wikipedia

• Radar passif — Un radar passif est un radar qui peut détecter et suivre un objet en utilisant les réflexions de sources étrangères au système telles que des stations de radiodiffusion ou de radiocommunication. C est un cas particulier du radar bistatique qui… …   Wikipédia en Français

• Radar sensor — Radio detection and ranging (radar) is used to sense angle, range and velocity of (moving) scatterers in the environment [Skolnik, M. I.: Introduction to Radar Systems, 3rd Ed. . McGraw Hill, 2005] [Stimson, G. W.: Introduction to Airborne Radar …   Wikipedia

• AN/FPS-16 — manned space program and the U.S. Air Force. The accuracy of Radar Set AN/FPS 16 is such that the position data obtained from point source targets has azimuth and elevation angular errors of less than 0.1 milliradian (approximately 0.006 degree)… …   Wikipedia

• Radar — For other uses, see Radar (disambiguation). A long range radar antenna, known as ALTAIR, used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on Kwajalein Atoll …   Wikipedia

• Direction finding — (DF) refers to the establishment of the direction from which a received signal was transmitted. This can refer to radio or other forms of wireless communication. By combining the direction information from two or more suitably spaced receivers… …   Wikipedia

• Secondary surveillance radar — SSR antenna of Deutsche Flugsicherung at Neubrandenburg, in Mecklenburg/Western Pomerania Secondary surveillance radar (SSR)[1] is a radar system used in air traffic control (ATC), that not only detects an …   Wikipedia

• radar — /ray dahr/, n. 1. Electronics. a device for determining the presence and location of an object by measuring the time for the echo of a radio wave to return from it and the direction from which it returns. 2. a means or sense of awareness or… …   Universalium

• Silkworm missile — The HY 2 Haiying (zh cpl|c=海鹰|p=hǎiyīng|l=Sea Eagle), known in Western media as the Silkworm missile, is an anti ship cruise missile made by the People s Republic of China and still used by many countries in the Middle East. Since the 1980s, the… …   Wikipedia