Air traffic control antenna and system
View Patent ↗Systems and methods relating to air traffic control and navigational aids for aircraft. An antenna system uses a multi-sector sensor that uses two vertical column antenna arrays per sector. Each pair of vertical column antenna arrays produces two beams that are off a boresight for each pair of antenna arrays. Wide angle monopulse processing is used to determine an azimuth or angle of arrival for an aircraft using at least one pair of the vertical column antenna arrays. Predetermined correction factors are applied to the azimuth for specific elevation values and, for elevation values without predetermined correction factors, interpolation between known predetermined correction values to arrive at the corrector factor to be applied.
1. An antenna system for use in air traffic control, the system comprising:
at least one pair of vertical column antenna arrays, said at least one pair producing two beams offset from boresight and said at least one pair covering a sector of a coverage of said antenna system,
wherein said antenna system is used for wide angle monopulse processing of at least one signal from an aircraft to determine a two-dimensional azimuth of said aircraft relative to said at least one pair of said vertical column antenna arrays,
wherein said azimuth is based on a logarithm of a difference in amplitude/phase of said two beams,
and wherein a correction factor is applied to said azimuth for specific values in elevation.
2. The antenna system according to claim 1 , wherein said antenna system further comprises a further plurality of pairs of vertical column antenna arrays, said further plurality of pairs of vertical column antenna arrays being for wide angle monopulse processing of said at least one signal from said aircraft to determine an elevation of said aircraft relative to at least one pair of said further plurality of pairs of vertical column antenna arrays.
3. The antenna system according to claim 1 , wherein at least one of said vertical column antenna arrays comprises a plurality of vertically arranged antenna array elements.
4. The antenna system according to claim 3 , wherein said antenna array elements comprise at least one of: dipoles antenna array elements, patch antenna array elements, dielectric resonators antenna elements, slot antenna elements, cavity based slot antenna elements, and open ended waveguide antenna elements.
5. The antenna system according to claim 2 , wherein said further plurality of pairs of vertical column antenna arrays is mounted atop said plurality of pairs of vertical column antenna arrays.
6. The antenna system according to claim 5 , wherein said further plurality of pairs of vertical column antenna arrays is tilted away from vertical atop said plurality of pairs of vertical column antenna arrays.
7. The antenna system according to claim 1 , wherein said at least one signal from said aircraft is transmitted by said aircraft in response to an interrogation signal.
8. The antenna system according to claim 1 , wherein said at least one signal from said aircraft is transmitted by said aircraft absent a ground sound interrogation signal.
9. The antenna system according to claim 1 , wherein said correction factor is predetermined for specific values in elevation.
10. The antenna system according to claim 1 , wherein said correction factor is interpolated between predetermined correction factor values for specific elevation values.
11. The antenna system according to claim 1 , wherein said antenna system is used to provide at least one navigational aid to aircraft, said at least one navigational aid being at least one of: DME, VOR, ILS, TLS, TACAN, VORTAC, Pseudo-VOR, APVOR, Pseudo-ILS, Pseudo-TACAN, and use of SSR as a PSR.
12. The antenna system according to claim 1 , wherein said antenna system has a multiple sector coverage using multiple pairs of said multiple vertical columns antenna arrays.
13. The antenna system according to claim 3 , wherein at least one of said vertical column antenna arrays comprises at least two vertically arranged antenna array elements.
14. The antenna system according to claim 1 , wherein the antenna system is comprised in a static, circular, multi-sector antenna sensor.
15. The antenna system according to claim 14 , wherein said azimuth is determined by reference to a predetermined lookup table.
16. The antenna system according to claim 14 , wherein the antenna sensor is also for use in wide angle monopulse processing of said at least one signal originating from an aircraft to determine an angle of arrival.