EP1217687A1 - Verfahren zum Messen und Kompensieren der Verformung einer Antenne und Antenne für solches Verfahren - Google Patents

Verfahren zum Messen und Kompensieren der Verformung einer Antenne und Antenne für solches Verfahren Download PDF

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Publication number
EP1217687A1
EP1217687A1 EP01403200A EP01403200A EP1217687A1 EP 1217687 A1 EP1217687 A1 EP 1217687A1 EP 01403200 A EP01403200 A EP 01403200A EP 01403200 A EP01403200 A EP 01403200A EP 1217687 A1 EP1217687 A1 EP 1217687A1
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EP
European Patent Office
Prior art keywords
antenna
deformation
radiating surface
electronic scanning
scanning antenna
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP01403200A
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English (en)
French (fr)
Inventor
Michel Thales Intellectual Property Renault
Thomas Thales Intellectual Property Merlet
Veronique Thales Intellectual Property Le Calvez
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Thales SA
Original Assignee
Thales SA
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Filing date
Publication date
Application filed by Thales SA filed Critical Thales SA
Publication of EP1217687A1 publication Critical patent/EP1217687A1/de
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
    • H01Q3/267—Phased-array testing or checking devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/27—Adaptation for use in or on movable bodies
    • H01Q1/28—Adaptation for use in or on aircraft, missiles, satellites, or balloons
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
    • H01Q3/2605—Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays

Definitions

  • the present invention relates to the field of antennas electronic scanning network; and more particularly a method of determination of the radiation pattern error due to the deformation of the radiating face of a network antenna and compensation for this error.
  • Such a antenna consists of a plurality of radiating elements, of the type dipole for example, generally arranged at the nodes of a plane mesh regular (rectangular, triangular, or more generally bi-periodic). AT each of these radiating elements is associated with a phase shifting device electronic control. To orient the radio beam in a pointing direction given, the signals sent or received by the different radiant elements are out of phase with each other so that the contributions to the antenna radiation of the various radiating elements are added in phase in the chosen direction.
  • the setpoint of the control of each phase shifter is developed by a computer called pointer.
  • Electronic antenna pointing control allows implementation of multiple radar functions on the same antenna, by example watch, pursuit and fire control.
  • the array antenna is in the form of a slab comprising a radiating surface and a thickness corresponding to stacking of a radiating element, a phase shifter, a distribution microwave and in some cases a microwave generator.
  • the thickness is for example a few tens of centimeters.
  • the quality of the radiation and pointing accuracy of the radio beam largely depend on the control of the electric wave plane.
  • the method currently used consists in defining a structure mechanical, supporting the radiating elements, the flatness of which provides the quality of the electric wave plane.
  • An antenna network is generally 5 to 10 times heavier than a radar antenna passive. Satisfying the rigidity requirements leads to the design of heavy structures, which penalize mobility and installation of equipment. The moving such equipment may not be possible by air and requires a high capacity road vehicle.
  • the means of installation are important, for example with a crane, and the reception structure is sophisticated. Installation on a ship may in particular be impossible.
  • An object of the invention is in particular to allow the realization an antenna with an electronic scanning array whose mobility, implantation and tactics are improved.
  • the invention has for object a method for determining the error of the radiation diagram of an electronic scanning antenna comprising an array of N elements radiant, the error being due to mechanical deformation of the surface radiating from the antenna, as determined from measurements of the mechanical deformation of n points of said surface in view correcting this error.
  • the invention particularly has the advantage that it allows a realization of an antenna with electronic scanning whose structure is lightened and simplified without compromising the quality of its diagram radiation. It makes it possible to produce an antenna at low cost and whose moving is facilitated.
  • the method uses optical measurements of the deformations of the antenna plane.
  • the method according to the invention is implemented at using light sources and optical sensors attached to the antenna itself. It does not use any error measurement device or system outside the antenna and allows the total autonomy of the antenna to be preserved, especially for a mobile antenna.
  • the invention makes it possible to compensate for mechanical deformations of the mechanical plane of the antenna induced by the conditions of operation and environment.
  • the invention makes it possible to keep a same quality of radiation pattern with an antenna whose deformations are ten to a hundred times higher than the tolerated deformations without implementing the invention.
  • the invention makes it possible to reduce notably the rigidity constraints.
  • the invention makes it possible to compensate for a permanent defect in the radiating surface of the antenna, it has the advantage of increasing the mechanical manufacturing tolerances of the antenna surface.
  • the invention also relates to a scanning antenna.
  • electronics comprising means implementing the method.
  • Figure 1 schematically illustrates an example of realization of an electronic scanning array antenna with a device for measuring the deformation of the radiating surface.
  • the deformation measurement is a type measurement optical.
  • a light source includes for example a laser or a diode electroluminescent placed behind the radiating surface 2 of the antenna.
  • the radiating surface of the antenna is substantially plane, it materializes, apart from defects, a reference plane for radar transmission.
  • a volume hologram 1 is placed at a point of the radiating surface 2 considered as a reference point of the surface radiating 2 from the antenna.
  • the light source associated with a hologram allows the emission, from the reference point of surface 2, of a beam luminous 3 in a plane substantially parallel to the reference plane of the radiant surface.
  • Fiber optic strips 4, 5 are fixed on the radiant surface.
  • the antenna has n fiber optic bars.
  • the receiving plane of a bar 4 is substantially perpendicular to the radiating surface on the one hand and substantially perpendicular to the beam luminous 3 which is received by the bar on the other hand.
  • the hologram is constructed for example by irradiation ultraviolet or short wavelength.
  • the hologram allows you to focus the light from the light source on each of the n bars by forming for example n beams.
  • the light beam 3 is anamorphic.
  • the beam emitted by the source becomes elliptical when passing through the hologram.
  • the volume hologram has the advantages of a small footprint and an easy realization.
  • FIG. 2 illustrates the reception plan of an example bar of optical fibers according to the invention.
  • Each fiber strip is a bundle of optical fibers having a flat and rigid end. The rest of the the beam is preferably flexible.
  • the reception plan includes sections 6 of small diameter optical fibers, for example around 250 micrometers.
  • Each silica fiber core 7 preferably comprises a 8 polymer coating transparent to electronic radar radiation.
  • Optical fiber has the advantage of being immune to radar radiation.
  • the bundle of optical fibers 6 extends behind the plane of the figure 2. In the example illustrated in FIG. 2, the optical fibers are divided into three layers superimposed in the reception plane. A lower layer 9 presents sections of juxtaposed fibers whose centers of the hearts are aligned along a line segment 12.
  • the intermediate layer 10 has juxtaposed sections in which the centers of the hearts are aligned according to a second line segment 13 parallel to the first.
  • a diaper upper 11 is parallel to the two layers already described 9, 10.
  • the centers 14, 15, 16 of the first fiber of each of the three layers are offset in the direction common to the first and second segments of line 12, 13 corresponding to that of an axis 17 of the abscissa of the centers of fibers.
  • the intercentre, or fiber diameter is the gap between the centers of two fibers juxtaposed with the same layer. Spacing between centers 14, 15 of two fibers juxtaposed with two offset layers is less than the Intercentre.
  • the abscissa of the center 15, 16 of the first fiber of a layer 10, 11 is greater than a third of the center to the abscissa of the center of the first fiber 14, 15 of the layer immediately lower 9, 10.
  • Each optical fiber in a strip is connected to a CCD receiver.
  • CCD receivers are installed directly on the fiber strip associated or are carried inside the antenna.
  • the embodiment with transfer inside the antenna, behind the radiating elements, by a suitable length of the optical fiber bundle of the strip present the advantage of avoiding a disturbance of the microwave field emitted by the antenna by CCD semiconductors.
  • a CCD group grouping the CCD receptors associated with a strip of fibers identifies the optical fiber or fibers lit by the light beam 3 on the receiving plane of the fiber strip.
  • Each CCD group provides a measurement of the displacement of the light beam on the associated strip of fiber, the displacement is measured along the axis of abscissa. The resolution of the measurement depends on the discreet spacing of the fibers along this axis, the diameter of the fiber core and the width of the illumination beam along this axis. Measuring a bar with a single layer of juxtaposed fibers provides better resolution when the fiber coating is removed. In the example in Figure 2, the different layers of superimposed and offset fibers allow obtain good resolution while retaining the coating of each fibers.
  • the bar according to Figure 2 is robust and inexpensive.
  • Each CCD group measures a displacement in one direction substantially perpendicular to the emission plane of the light beam 3.
  • Each CCD group provides a measurement of the displacement of the fixing point to the radiating surface of the optical fiber strip associated therewith. Each displacement is measured relative to the reference point of the radiant surface.
  • the device described above makes it possible to measure the relative displacement of n points of the radiating surface of the antenna by relative to the reference point and in the direction substantially perpendicular to the reference plane of the radiating surface.
  • All n CCD groups are connected by an interface to a card Calculation. From the number n of points on the radiating surface whose displacement is measured, the calculation card makes an estimate of the actual displacement of each of the N many radiating elements of the radiating surface of the antenna. For example for an antenna presenting a few hundred to a few thousand radiating elements, the number n of displacement measurement points is advantageously between one and a few dozen.
  • the card of calculation elaborates an approximate form of the real deformation of the surface radiant by a linear combination of six elementary forms of deformation corresponding in this example to the first three modes proper deformation of the planar antenna and the three extreme forms of wind deformations.
  • the number of points on the surface whose displacement is measured is between 10 and 20 and preferably between 12 and 18, and these points are placed in characteristic zones of each shape.
  • Some points can be associated with several elementary forms when the method identifies their participation in each of them they. In the method of the invention, the position of each measurement point and their number is calculated beforehand.
  • Every couple of a point measure and of an elementary form is associated a coefficient which characterizes the part of the displacement of the measuring point compared to the displacement maximum seen by the surface in this elementary form.
  • the points of measure used to identify the contribution of each form elementary when the defined coefficients are comparable to the coefficients of an independent system of linear equations.
  • each attachment point of the fiber strips allows to separate the contribution of each elementary form to the form approximate to the real deformation.
  • the elementary forms of deformation depend on the geometry of the radiating surface, for example square, rectangular, round, and the fixing of the antenna plate on its support.
  • the calculation card then elaborates and for each radiating element of the antenna, an estimate of the distance between its theoretical position in the absence of deformation of the surface and its estimated real position. This estimated distance represents a measure of the diagram error radiation from the deformed antenna.
  • the map of calculation develops a phase deviation correction value to be applied to the phase shifting device associated with the radiating element.
  • a digital link transmits the phase deviation correction information to the pointing of the radar which controls the phases of the radiating elements.
  • the number of deformation forms to be used for the estimation of the actual deformation of the antenna depends on the precision of the phase shifters the antenna. It is at least three. For imprecise phase shifters, the number of deformation forms can be limited to 3. For phase shifters high quality with high precision, a number of shapes of larger deformation allows a better estimate.
  • All of the correction calculations and their transmission to the timekeeping calculator is realized in less than ten milliseconds, it allows a fairly quick correction taking into account the mechanical strain rates whose frequencies own are in the range of one tenth to ten Hertz.
  • the optical displacement measurements of the n points of the radiating surface are renewed at a high frequency in the range of one hundred to a thousand Hertz allowing correction of the radar pointing to a faster rate than that of the annoying degradation of the diagram of radiation due to mechanical deformations of the radiating surface.
  • the correction can be made outside of a burst of pulses.
  • the application of the correction calculated according to the invention allows the emission of a radar wave whose radiation pattern is corrected disturbances due to the deformation of the radiating surface of the antenna measured during antenna operation.
  • the invention allows in particular to reduce the increase in the width of the main lobe and the rise in the level of the secondary lobes of the diagram which are observed when a radar antenna deforms.
  • the invention allows improve the performance of a deforming antenna.
  • Radar emission is corrected in real time.
  • the invention allows the emission of a plane electromagnetic wave from a mechanical plane distorted from the antenna surface.
  • the number n of measurement sensors deformation is from one to a few tens.
  • the invention makes it possible to correct deformation amplitudes up to ten millimeters relative to the antenna reference plane.
  • the invention is particularly suitable for a multifunction radar which requires a large precision, it eases the rigidity constraints of its antenna.
  • the invention also makes it possible to improve the performance of an antenna having a permanent geometry defect, for example in manufacturing or accidental.
  • the invention makes it possible in particular to soften the tolerances of flatness in manufacturing.
  • the invention makes it possible to correct amplitudes of deformation increased by a factor of ten to one hundred compared to the amplitudes of tolerated deformations to guarantee control of the electric wave plane in the prior art.
  • the antenna shown in Figure 3 has n sources luminous 19, 20 placed at n points of the radiating surface and illuminating sequentially a sensor 21 fixed at a reference point on the surface radiant, which is represented by its reference plane 22.
  • a light source preferably comprises a laser behind the plane of the radiating surface and a mirror at the point of the surface whose displacement is to be measured.
  • the non-metallic mirror is produced for example by stack of optical dielectric layers, it returns the light wave of the laser towards sensor 21.
  • the light source has the advantage of not disturb the electromagnetic radiation from the antenna.
  • Figure 4 illustrates the sensor 21, it comprises a matrix 24 of micro lenses whose plane, shown in Figure 4 by the line 25, is substantially perpendicular in terms of the radiating surface.
  • the sensor has a CCD 23 strip perpendicular to the surface of the antenna and it is connected to means of calculation.
  • the sensor 21 is preferably placed on the edge of the antenna so avoid disturbance of the electromagnetic field emitted by it.
  • the radius of the light wave 26 emitted by the source placed at a first point 27 of the antenna surface results in a spacing between two successive focusing tasks of micro lenses.
  • the measure of the spacing on the CCD strip 23 allows the distance d between the source at the first point 27 and the matrix 24 with very high precision.
  • the sequential illumination of the sensor by the n sources allows successive evaluation of the relative displacement of each of the n points of the surface of the antenna where the light sources are placed, the displacement being evaluated with respect to the fixation reference point of the sensor 21 and in the direction substantially perpendicular to the plane of reference 22 of the radiating surface.
  • the n light sources illuminate preferably directionally to the sensor 21.
  • This variant has the advantage of using a sensor and a commercially available electronic processing assembly.
  • the variant can be modified by adding a light source additional for example in the center of the radiating surface, and differentiating the displacement of the additional source and the displacements of other sources.
  • This change provides displacement measurements with respect to a reference placed at a point any surface of the antenna, for example the center.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Astronomy & Astrophysics (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Remote Sensing (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
EP01403200A 2000-12-21 2001-12-11 Verfahren zum Messen und Kompensieren der Verformung einer Antenne und Antenne für solches Verfahren Withdrawn EP1217687A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0016774A FR2818812B1 (fr) 2000-12-21 2000-12-21 Procede de mesure et compensation de la deformation de la surface rayonnante d'une antenne et antenne comportant des moyens mettant en oeuvre un tel procede
FR0016774 2000-12-21

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EP1217687A1 true EP1217687A1 (de) 2002-06-26

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EP01403200A Withdrawn EP1217687A1 (de) 2000-12-21 2001-12-11 Verfahren zum Messen und Kompensieren der Verformung einer Antenne und Antenne für solches Verfahren

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EP (1) EP1217687A1 (de)
FR (1) FR2818812B1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3064757A1 (fr) * 2017-03-29 2018-10-05 Thales Dispositif de calibration d'un systeme d'imagerie et procede de calibration associe

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2923595B1 (fr) * 2007-11-09 2009-12-11 Thales Sa Capteur optique pour mesurer la deformation au cours du temps d'une structure plane deformable
FR2934676B1 (fr) * 2008-08-01 2010-08-20 Thales Sa Capteur polarimetrique pour la mesure de la deformation subie par une surface.

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4578680A (en) 1984-05-02 1986-03-25 The United States Of America As Represented By The Secretary Of The Air Force Feed displacement correction in a space fed lens antenna
US5003314A (en) 1989-07-24 1991-03-26 Cubic Defense Systems, Inc. Digitally synthesized phase error correcting system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4578680A (en) 1984-05-02 1986-03-25 The United States Of America As Represented By The Secretary Of The Air Force Feed displacement correction in a space fed lens antenna
US5003314A (en) 1989-07-24 1991-03-26 Cubic Defense Systems, Inc. Digitally synthesized phase error correcting system

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CONCEPTUAL DESIGN OF A SURFACE MEASUREMENT SYSTEM FOR LARGE DEPLOYABLE SPACE ANTENNAS, 1981
NEISWANDER R. S.: "Conceptual Design of a Surface Measurement System for Large Deployable Space Antennas", LARGE SPACE SYSTEMS TECHNOLOGY, NASA, vol. 2, no. 2215, 16 November 1981 (1981-11-16) - 19 November 1981 (1981-11-19), pages 631 - 639, XP001023805 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3064757A1 (fr) * 2017-03-29 2018-10-05 Thales Dispositif de calibration d'un systeme d'imagerie et procede de calibration associe
US11022677B2 (en) 2017-03-29 2021-06-01 Thales Device for calibrating an imaging system and associated calibrating method
GB2563122B (en) * 2017-03-29 2022-12-28 Thales Sa Device for calibrating an imaging system and associated calibrating method

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Publication number Publication date
FR2818812B1 (fr) 2004-06-04
FR2818812A1 (fr) 2002-06-28

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