EP0002982A1 - Conical scan antenna for tracking radar - Google Patents

Conical scan antenna for tracking radar Download PDF

Info

Publication number
EP0002982A1
EP0002982A1 EP78400242A EP78400242A EP0002982A1 EP 0002982 A1 EP0002982 A1 EP 0002982A1 EP 78400242 A EP78400242 A EP 78400242A EP 78400242 A EP78400242 A EP 78400242A EP 0002982 A1 EP0002982 A1 EP 0002982A1
Authority
EP
European Patent Office
Prior art keywords
reflector
conical scanning
auxiliary
antenna system
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.)
Ceased
Application number
EP78400242A
Other languages
German (de)
French (fr)
Inventor
Francois Salvat
Jean Bouko
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thales SA
Original Assignee
Thomson CSF SA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Thomson CSF SA filed Critical Thomson CSF SA
Publication of EP0002982A1 publication Critical patent/EP0002982A1/en
Ceased legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
    • H01Q19/10—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces
    • H01Q19/18—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces having two or more spaced reflecting surfaces
    • H01Q19/19—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces having two or more spaced reflecting surfaces comprising one main concave reflecting surface associated with an auxiliary reflecting surface
    • H01Q19/195—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces having two or more spaced reflecting surfaces comprising one main concave reflecting surface associated with an auxiliary reflecting surface wherein a reflecting surface acts also as a polarisation filter or a polarising device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q25/00—Antennas or antenna systems providing at least two radiating patterns
    • H01Q25/001—Crossed polarisation dual antennas
    • 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
    • H01Q3/12—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system using mechanical relative movement between primary active elements and secondary devices of antennas or antenna systems
    • H01Q3/16—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system using mechanical relative movement between primary active elements and secondary devices of antennas or antenna systems for varying relative position of primary active element and a reflecting device
    • H01Q3/20—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system using mechanical relative movement between primary active elements and secondary devices of antennas or antenna systems for varying relative position of primary active element and a reflecting device wherein the primary active element is fixed and the reflecting device is movable

Definitions

  • the present inventior relates to a conical scanning antenna system for tracking radar.
  • a tracking radar measures the coordinates of a target and provides data that can be used to determine the target's trajectory and predict its future position. To establish this prediction, practically all the data available in a radar can be used, the distance, the angle of site, the bearing, the Doppler frequency; this means that any a priorl radar can be considered as a tracking radar from the moment when the output information which it delivers is adequately processed.
  • a tracking radar is distinguished from other radars by the way in which the angular tracking of the target is carried out, and this angular tracking aims to define an error indicating the angular offset relative to the axis of the antenna, the direction in which the target is located, this error signal supplying servomechanisms provided for bringing the axis of the antenna back to the direction of the target.
  • this error signal supplying servomechanisms provided for bringing the axis of the antenna back to the direction of the target.
  • a first method is the detection of a target by flipping a diagram (sequential lobing in English), a second method is the conical scanning and a third method is the monopulse method.
  • the antenna system according to the invention relates to the second method, called conical scanning, the principle of which will be recalled.
  • the antenna comprises a focusing revolution system, paraboloid or lens, illuminated by a primary source whose phase center describes around the focal axis of the revolution system a circle of determined radius located in the focal plane.
  • the radiation pattern is no longer centered on the axis of the focusing system, but rotates in space so that the direction of maximum radiation describes a cone whose half angle at the top is called strabismus angle antenna (squint angle in English).
  • the amplitude of the signal delivered by the antenna is thus modulated at the frequency of rotation of the diagram and.
  • the modulation rate is a function of the target's angle relative to the axis of rotation.
  • the modulation signal extracted from the echo signal is used in servomechanisms to slave the antenna in position on the target.
  • the beams radiated by the antenna all overlap along the axis of the system of revolution and in general the level of overlap is such that it has an optimal value, compromised between the slope at origin which gives the accuracy of the pointing and the range of the radar.
  • the radiation diagram is the same at transmission and reception, providing the possibility by analysis of the diagram on transmission, to know the frequency of rotation of the diagram, usable for interference purposes .
  • An embodiment made on this principle comprises a primary source of the monopulse type delivering signals in a sum channel and in two difference channels, one in bearing, the other in elevation.
  • the sum channel is combined with the difference channels, and the conical scanning diagram is obtained, on reception, by a rotating variable phase shifter varying the phase between the difference and sum signals.
  • the radiation pattern obtained is off-center and rotates at the speed of the phase shifter.
  • This embodiment defines a receiver with a single channel which is however not immune to errors in determining the angles due to fluctuations in the amplitude of the echo. In addition, it leads to relatively complex and therefore costly embodiments.
  • the object of the invention is a conical scanning antenna at reception capable of tracking depolarizing targets. According to the invention therefore, the possibility of detecting the rotation frequency from the radiation diagram is deleted.
  • conical scanning antenna systems are generally less complex and less costly to produce than diagram tilting systems or monopulse systems
  • a conical scanning antenna system which to a Cassegrain type system, that is to say comprising a main parabolic reflector and an auxiliary hyperbolic reflector, with in addition means acting in such a way that the emission diagram is fixed, for example centered on the axis of the antenna and that the transmitted wave is with rectilinear polarization and that the diagram on reception is conical scanning, capable of receiving a wave reflected by the target and of rectilinear polarization orthogonal to the polarization of the wave at l 'program.
  • the conical scanning antenna system for tracking radar is a Cassegrain type antenna, comprising a main parabolic reflector and two hyperbolic auxiliary reflectors, a focal point of one being in a focal plane of the other and a primary source radiating in two rectilinear orthogonal polarizations.
  • the subject of the invention is the definition of a conical scanning antenna system at reception only for tracking radar, capable of tracking targets on the one hand, and not being able to be subjected on the other to interference based on the knowledge of the frequency of rotation of the radiation diagram established from the signals transmitted.
  • FIG. 1 schematically represents such an antenna of the Cassegrain type, that is to say comprising at least one main parabolic reflector and one hyperbolic auxiliary reflector to which are added the means enabling it to operate in accordance with the aims of the invention and achieve results.
  • the antenna comprises a main reflector 1, which is a paraboioide of revolution around the axis OX, a primary source 2 placed in the embodiment described, in the axis of the main reflector, a first auxiliary reflector 3, portion of a hyperboloid of revolution around the axis 0X and a second auxiliary reflector 4, portion of a hyperboloid of revolution and whose axis SY has the particularity of being inclined relative to the focal axis OX of the system.
  • the second focal point F 'of the hyperbolic auxiliary reflector 3 is coincident with the phase center of the primary source 2.
  • the first focal point of the hyperbolic auxiliary reflector 4 or F1 is in the focal plane P of the parabolic reflector 1 and of the first auxiliary reflector 3 and its second focus F'1 is in the second focal plane P 'of the first hyperbolic reflector 3, containing the phase center of the primary source.
  • the antenna system must be capable of receiving the waves returned by a target having a depolarizing effect: the primary source 2 consequently must be able to radiate according to two orthogonal rectilinear polarizations.
  • this primary source is a horn of circular section located at the end of a guide 6 of circular section supplied by two guides 7 and 8 of rectangular section.
  • the guide 7 propagates a wave whose polarization vector is for example vertical while the guide 8 propagates a wave whose polarization vector is horizontal.
  • the guide 7 feeds the horn at transmission, while the guide 8 receives the wave reflected by the target.
  • the main parabolic reflector 1 conforms to any main reflector of a Cassegrain antenna.
  • the first hyperbolic auxiliary reflector 3 the focal points of which are points F and F ', is a semi-transparent reflector of revolution constituted by wires parallel to the polarization vector of the emitted wave, in this case in the example described, vertical .
  • This reflector therefore reflects the wave emitted by an electric vector. E towards main reflector 1 which reflects it in space parallel to the axis OX.
  • the hyperbolic auxiliary reflector with wires 3 allows the reflected wave to pass, which is taken up by the second hyperbolic auxiliary reflector 4.
  • This auxiliary hyperbolic reflector 4 is a solid reflector, portion of a hyperboloide, rotating around its axis SY, inclined at an angle ⁇ relative to the focal axis OX of the system, but whose apex S is located on the focal axis OX.
  • This reflector is rotated by a motor shown schematically by M.
  • the rotation of the auxiliary reflector 4, inclined relative to the focal axis of the system allows reception to make a conical scan.
  • the focal point F1 of the hyperbolic reflector 4 describes a center circle F, focal point of the main reflector and of the first auxiliary reflector 3, in the focal plane P.
  • the radiation diagram 3. the reception DR, visible in FIG. 2, revolves around the OX focal axis of the system with a level of overlap of the lobes on the axis, defined by the angle of inclination ⁇ of the axis SY relative to the axis OX.
  • FIG. 2 also shows the radiation diagram for the emission DE which is fixed and centered on the axis of the system. Also included was the axis of the AL lobe and the DC direction in which the target is located.
  • FIG. 1 shows the path of a wave emitted in solid lines and that of a wave reflected in broken lines.
  • the parallel wires constituting the hyperbolic auxiliary reflector 3 used for transmission are of relatively small dimensions depending on the operating frequency band of the antenna.
  • the wires In the Ku band for example, the wires have a diameter of the order of 0.12 in step 0.6 and the diameter of the reflector does not exceed 110 cm, with a focal length of the order of 171 cm. From the mechanical point of view, the wires are supported either by a so-called sandwich structure or by a single self-adapted skin.
  • the structure which has the least thickness so that the rotation of the second reflector is not hampered. If a self-adjusting skin is used, compensations must be provided, in general a network of wires orthogonal to the first ones which are chosen such that they do not cause disturbances on reception.
  • the rotating auxiliary reflector 4 in an exemplary embodiment has a diameter of the order of 95 cm and a focal length of 171 cm, while the main reflector has a diameter of the order of 800 cm and a focal length of 255 cm.
  • FIG. 3 presents a schematic diagram of a conical scanning radar using the antenna system which has been described. This classic diagram will not be described in detail.
  • the primary source 2 connected on the one hand to the transmitter 10 supplied by the synchronization generator 11, and on the other hand via the TR 9 to the reception part comprising a mixer circuit 12 connected to the generator 13 of the local oscillator and to an intermediate frequency amplifier 14 followed by a detector 15.
  • This amplifier is connected to a circuit 16 for automatic gain control connected to the selection circuit 17 from the distance.
  • This circuit is supplied by the distance tracking circuit 18 connected to the synchronization generator 11.
  • the distance selection circuit 17 is connected to the field demodulation circuit 18 and to the site demodulation circuit 20, which receive information reference point and site respectively of the drive motor M of the hyperbolic auxiliary reflector 4 of the antenna via a circuit 25.
  • a conical scanning antenna system for tracking radar in which, the Cassegrain type antenna, emits according to a radiation diagram centered on the axis and receives according to a conical scanning, a depolarized reflected wave.
  • Such an antenna, fitted to a tracking radar has advantages that have been reported at the beginning of the description, in particular, p im ossi- bility to determine the rotational frequency of the conical scan pattern.
  • Another advantage is the non-disturbance of the operation of the radar in bad atmospheric conditions, due to the fact that the rain drops for example are very little depolarizing.

Landscapes

  • Aerials With Secondary Devices (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

Système d'antenne à balayage conique à la réception du type Cassegrain comportant un réflecteur principal parabolique (1) et deux réflecteurs auxiliaires hyperboliques (3, 4) avec un foyer de l'un dans un plan focal de l'autre. L'un de ces réflecteurs (3) est semi-transparent et l'autre (4) est animé d'un mouvement de rotation autour d'un axe (54) incliné par rapport à l'axe focal (ox) du système. Application aux radars de poursuite.Cassegrain type reception cone scanning antenna system comprising a parabolic main reflector (1) and two hyperbolic auxiliary reflectors (3, 4) with a focal point of one in a focal plane of the other. One of these reflectors (3) is semi-transparent and the other (4) is rotated around an axis (54) inclined relative to the focal axis (ox) of the system. Application to tracking radars.

Description

La présente inventior. concerne un système d'antenne à balayage conique pour radar de poursuite.The present inventior. relates to a conical scanning antenna system for tracking radar.

Un radar de poursuite mesure les coordonnées d'une cible et fournit des données qui peuvent être utilisées pour déterminer la trajectoire de la cible et prédire sa position future. Pour établir cette prédiction, pratiquement toutes les données disponibles dans un radar peuvent être utilisées, la distance, l'angle de site, le gisement, la fréquence Doppler ; ceci fait que tout radar a priorl peut- être considéré comme un radar de poursuite à partir du moment où l'information de sortie qu'il délivre est traitée de façon adéquate. Toutefois un radar de poursuite se distingue des autres radars par la facon dont la poursuite angulaire de la cible est effectuée, et cette poursuite angulaire a pour but de définir une erreur indiquant le déport angulaire par rapport à l'axe de l'antenne, de la direction dans laquelle se trouve la cible, ce signal d'erreur alimentant des servomécanismes prévus pour ramener l'axe de l'antenne sur la direction de la cible. D'une façon générale on considère trois méthodes devenues classiques pour produire ce signal d'erreur.A tracking radar measures the coordinates of a target and provides data that can be used to determine the target's trajectory and predict its future position. To establish this prediction, practically all the data available in a radar can be used, the distance, the angle of site, the bearing, the Doppler frequency; this means that any a priorl radar can be considered as a tracking radar from the moment when the output information which it delivers is adequately processed. However, a tracking radar is distinguished from other radars by the way in which the angular tracking of the target is carried out, and this angular tracking aims to define an error indicating the angular offset relative to the axis of the antenna, the direction in which the target is located, this error signal supplying servomechanisms provided for bringing the axis of the antenna back to the direction of the target. Generally we consider three methods become conventional to produce this error signal.

Une première méthode est la détection d'une cible par basculement de diagramme (sequential lobing en anglais), une seconde méthode est le balayage conique et une troisième méthode est la méthode monopulse.A first method is the detection of a target by flipping a diagram (sequential lobing in English), a second method is the conical scanning and a third method is the monopulse method.

Le système d'antenne suivant l'invention relève de la seconde méthode, dite du balayage conique, dont le principe va être rappelé. Dans un système à balayage conique, l'antenne comporte un système de révolution focalisant, paraboloïde ou lentille, éclairé par une source primaire dont le centre de phase décrit autour de l'axe focal du système de révolution un cercle de rayon déterminé situé dans le plan focal. Pour une telle antenne, le diagramme de rayonnement n'est plus centré sur l'axe du système focalisant, mais tourne dans l'espace de sorte que la direction de rayonnement maximal décrit un cône dont le demi angle au sommet est appelé angle de strabisme de l'antenne (squint angle en langue anglaise).The antenna system according to the invention relates to the second method, called conical scanning, the principle of which will be recalled. In a conical scanning system, the antenna comprises a focusing revolution system, paraboloid or lens, illuminated by a primary source whose phase center describes around the focal axis of the revolution system a circle of determined radius located in the focal plane. For such an antenna, the radiation pattern is no longer centered on the axis of the focusing system, but rotates in space so that the direction of maximum radiation describes a cone whose half angle at the top is called strabismus angle antenna (squint angle in English).

L'amplitude du signal délivré par l'antenne est ainsi modulée à la fréquence de rotation du diagramme et. le taux de modulation est fonction de l'angle de la cible par rapport à l'axe de rotation. Le signal de modulation extrait du signal écho est utilisé dans des servomécanismes pour asservir l'antenne en position sur la cible.The amplitude of the signal delivered by the antenna is thus modulated at the frequency of rotation of the diagram and. the modulation rate is a function of the target's angle relative to the axis of rotation. The modulation signal extracted from the echo signal is used in servomechanisms to slave the antenna in position on the target.

Du fait de la symétrie de révolution, les faisceaux rayonnés par l'antenne se recoupent tous suivant l'axe du système de révolution et en général le niveau de recoupement est tel qu'il a une valeur optimale, compromis entre la pente à l'origine qui donne la précision du pointage et la portée du radar.Because of the symmetry of revolution, the beams radiated by the antenna all overlap along the axis of the system of revolution and in general the level of overlap is such that it has an optimal value, compromised between the slope at origin which gives the accuracy of the pointing and the range of the radar.

Dans une antenne à balayage conique classique le diagramme de rayonnement est le même à l'émission et à la réception, fournissant la possibilité par analyse du diagramme à l'émission, de connaître la fréquence de rotation du diagramme, utilisable à des fins de brouillage.In a conventional conical scanning antenna, the radiation diagram is the same at transmission and reception, providing the possibility by analysis of the diagram on transmission, to know the frequency of rotation of the diagram, usable for interference purposes .

Il est des applications, où cette possibilité de détection de la fréquence de rotation du diagramme de rayonnement de l'antenne à balayage conique doit être supprimée.There are applications where this possibility of detecting the frequency of rotation of the radiation pattern of the conical scanning antenna must be eliminated.

Dans une solution de l'art antérieur, on a proposé d'émettre suivant un diagramme de rayonnement centré sur l'axe de l'antenne et de recevoir suivant un diagramme de rayonnement à balayage conique. Une réalisation faite sur ce principe comporte une source primaire du type monopulse délivrant des signaux dans une voie somme et dans deux voies différence, l'une en gisement, l'autre en site. La voie somme est combinée avec les voies différence, et le diagramme en balayage conique est obtenu, à la réception, par un déphaseur variable tournant faisant varier la phase entre les signaux différence et somme. Le diagramme de rayonnement obtenu est décentré et tourne à la vitesse du déphaseur. Cette réalisation définit un récepteur à un seul canal qui n'est toutefois pas à l'abri d'erreurs sur la détermination des angles dues à des fluctuations de l'amplitude de l'écho. De plus elle conduit à des réalisations relativement complexes et partant coûteuses.In a solution of the prior art, it has been proposed to emit according to a radiation diagram centered on the axis of the antenna and to receive according to a conical scanning radiation diagram. An embodiment made on this principle comprises a primary source of the monopulse type delivering signals in a sum channel and in two difference channels, one in bearing, the other in elevation. The sum channel is combined with the difference channels, and the conical scanning diagram is obtained, on reception, by a rotating variable phase shifter varying the phase between the difference and sum signals. The radiation pattern obtained is off-center and rotates at the speed of the phase shifter. This embodiment defines a receiver with a single channel which is however not immune to errors in determining the angles due to fluctuations in the amplitude of the echo. In addition, it leads to relatively complex and therefore costly embodiments.

L'objet de l'invention est une antenne à balayage conique à la réception capable de poursuivre des cibles dépolarisantes, Suivant l'invention donc, la possibilité de détection de la fréquence de rotation du diagramme de rayonnement est supprimée.The object of the invention is a conical scanning antenna at reception capable of tracking depolarizing targets. According to the invention therefore, the possibility of detecting the rotation frequency from the radiation diagram is deleted.

Les systèmes d'antenne à balayage conique étant de façon générale moins complexes et moins coûteux à réaliser que les systèmes à basculement de diagramme ou les systèmes monopulse, on se propose suivant l'invention de réaliser un système d'antenne à balayage conique, ressortissant à un système du type Cassegrain, c'est-à-dire comportant un réflecteur principal parabolique et un réflecteur auxiliaire hyperbolique, avec en plus des moyens agissant de façon telle que le diagramme à l'émission est fixe, par exemple centré sur l'axe de l'antenne et que l'onde émise est à polarisation rectiligne et que le diagramme à la réception est à balayage conique, capable de recevoir une onde réfléchie par la cible et de polarisation rectiligne orthogonale à la polarisation de l'onde à l'émission.Since conical scanning antenna systems are generally less complex and less costly to produce than diagram tilting systems or monopulse systems, it is proposed according to the invention to provide a conical scanning antenna system, which to a Cassegrain type system, that is to say comprising a main parabolic reflector and an auxiliary hyperbolic reflector, with in addition means acting in such a way that the emission diagram is fixed, for example centered on the axis of the antenna and that the transmitted wave is with rectilinear polarization and that the diagram on reception is conical scanning, capable of receiving a wave reflected by the target and of rectilinear polarization orthogonal to the polarization of the wave at l 'program.

Suivant l'invention également, le système d'antenne à balayage conique pour radar de poursuite est une antenne du type Cassegrain, comportant un réflecteur principal parabolique deux réflecteurs auxiliaires hyperboliques, un foyer de l'un se trouvant dans un plan focal de l'autre et une source primaire rayonnant suivant deux polarisations rectilignes orthogonales.Also according to the invention, the conical scanning antenna system for tracking radar is a Cassegrain type antenna, comprising a main parabolic reflector and two hyperbolic auxiliary reflectors, a focal point of one being in a focal plane of the other and a primary source radiating in two rectilinear orthogonal polarizations.

D'autres caractéristiques et avantages de la présente invention ressortiront de la description d'un exemple de réalisation donné à l'aide des figures qui représentent :

  • - la figure 1, une représentation schématique du système d'antenne suivant l'invention ;
  • - la figure 2, les diagrammes de rayonnement à la réception et à l'émission ;
  • - la figure 3, un diagramme schématique d'un radar de poursuite incorporant le système d'antenne de la figure 1.
Other characteristics and advantages of the present invention will emerge from the description of an exemplary embodiment given with the aid of the figures which represent:
  • - Figure 1, a schematic representation of the antenna system according to the invention;
  • - Figure 2, the radiation patterns on reception and transmission;
  • - Figure 3, a schematic diagram of a tracking radar incorporating the antenna system of Figure 1.

Ainsi que cela a été indiqué dans l'introduction à la présente description, l'invention a pour objet la définition d'un système d'antenne à balayage conique à la réception seulement pour radar de poursuite, capable d'effectuer la poursuite de cibles à effet dépolarisant d'une part, et de ne pouvoir être soumis d'autre part à un brouillage base sur la connaissance de la fréquence de rotation du diagramme de rayonnement établie à partir des signaux émis.As indicated in the introduction to the present description, the subject of the invention is the definition of a conical scanning antenna system at reception only for tracking radar, capable of tracking targets on the one hand, and not being able to be subjected on the other to interference based on the knowledge of the frequency of rotation of the radiation diagram established from the signals transmitted.

La figure 1 représente de façon schématique une telle antenne du type Cassegrain, c'est-à-dire comportant au moins un réflecteur principal parabolique et un réflecteur auxiliaire hyperbolique auxquels on ajoute les moyens lui permettant de fonctionner en conformité avec les buts de l'invention et d'en atteindre les résultats.FIG. 1 schematically represents such an antenna of the Cassegrain type, that is to say comprising at least one main parabolic reflector and one hyperbolic auxiliary reflector to which are added the means enabling it to operate in accordance with the aims of the invention and achieve results.

L'antenne comporte un réflecteur principal 1, qui est un paraboioide de révolution autour de l'axe OX, une source primaire 2 placée dans l'exemple de réalisation décrit, dans l'axe du réflecteur principal, un premier réflecteur auxiliaire 3, portion d'un hyperboloide de révolution autour de l'axe 0X et un second réflecteur auxiliaire 4, portion d'un hyperboloïde de révolution et dont l'axe SY présente la particularité d'être incliné par rapport à l'axe focal OX du système.The antenna comprises a main reflector 1, which is a paraboioide of revolution around the axis OX, a primary source 2 placed in the embodiment described, in the axis of the main reflector, a first auxiliary reflector 3, portion of a hyperboloid of revolution around the axis 0X and a second auxiliary reflector 4, portion of a hyperboloid of revolution and whose axis SY has the particularity of being inclined relative to the focal axis OX of the system.

Les positions réciproques de ces réflecteurs sont telles que le point F est à la fois foyer du réflecteur parabolique principal 1 et du réflecteur auxiliaire 3.The reciprocal positions of these reflectors are such that the point F is both the focal point of the main parabolic reflector 1 and of the auxiliary reflector 3.

Le second foyer F' du réflecteur auxiliaire hyperbolique 3 se trouve confondu avec le centre de phase de la source primaire 2. Le premier foyer du réflecteur auxiliaire hyperbolique 4 soit F1 se trouve dans le plan focal P du réflecteur parabolique 1 et du premier réflecteur auxiliaire 3 et son second foyer F'1 se trouve dans le second plan focal P' du premier réflecteur hyperbolique 3, contenant le centre de phase de la source primaire.The second focal point F 'of the hyperbolic auxiliary reflector 3 is coincident with the phase center of the primary source 2. The first focal point of the hyperbolic auxiliary reflector 4 or F1 is in the focal plane P of the parabolic reflector 1 and of the first auxiliary reflector 3 and its second focus F'1 is in the second focal plane P 'of the first hyperbolic reflector 3, containing the phase center of the primary source.

Suivant l'invention, le système d'antenne doit être capable de recevoir les ondes renvoyées par une cible présentant un effet dépolarisant : la source primaire 2 par conséquent doit pouvoir rayonner suivant deux polarisations rectilignes orthogonales. Suivant un exemple de réalisation cette source primaire est un cornet de section circulaire situé en bout d'un guide 6 de section circulaire alimenté par deux guides 7 et 8 de section rectangulaire. Le guide 7 propage une onde dont le vecteur polarisation est par exemple vertical tandis que le guide 8 propage une onde dont le vecteur polarisation est horizontal. Suivant l'invention, par exemple le guide 7 alimente le cornet à l'émission, tandis que le guide 8 reçoit l'onde réfléchie par la cible.According to the invention, the antenna system must be capable of receiving the waves returned by a target having a depolarizing effect: the primary source 2 consequently must be able to radiate according to two orthogonal rectilinear polarizations. According to an exemplary embodiment, this primary source is a horn of circular section located at the end of a guide 6 of circular section supplied by two guides 7 and 8 of rectangular section. The guide 7 propagates a wave whose polarization vector is for example vertical while the guide 8 propagates a wave whose polarization vector is horizontal. According to the invention, for example the guide 7 feeds the horn at transmission, while the guide 8 receives the wave reflected by the target.

Le réflecteur principal parabolique 1 est conforme à tout réflecteur principal d'une antenne Cassegrain.The main parabolic reflector 1 conforms to any main reflector of a Cassegrain antenna.

Le premier réflecteur auxiliaire hyperbolique 3 dont les foyers sont les points F et F', est un réflecteur de révolution semi-transparent constitué par des fils parallèles au vecteur polarisation de l'onde émise, en l'occurrence dans l'exemple décrit, vertical. Ce réflecteur réfléchit par conséquent l'onde émise de vecteur électrique E en direction du réflecteur principal 1 qui la réfléchit dans l'espace parallèlement à l'axe OX.The first hyperbolic auxiliary reflector 3, the focal points of which are points F and F ', is a semi-transparent reflector of revolution constituted by wires parallel to the polarization vector of the emitted wave, in this case in the example described, vertical . This reflector therefore reflects the wave emitted by an electric vector. E towards main reflector 1 which reflects it in space parallel to the axis OX.

A la réception, l'onde réfléchie par la cible dépolarisante considérée à son vecteur de polarisation horizontal. Dans ces conditions le réflecteur auxiliaire hyperbolique à fils 3 laisse passer l'onde réfléchie, qui est reprise par le second réflecteur auxiliaire hyperbolique 4.On reception, the wave reflected by the depolarizing target considered at its horizontal polarization vector. Under these conditions, the hyperbolic auxiliary reflector with wires 3 allows the reflected wave to pass, which is taken up by the second hyperbolic auxiliary reflector 4.

Ce réflecteur auxiliaire hyperbolique 4 est un réflecteur plein, portion d'un hyperboloide, tournant autour de son axe SY, incliné d'un angle α par rapport à l'axe focal OX du système, mais dont le sommet S est situé sur l'axe focal OX.This auxiliary hyperbolic reflector 4 is a solid reflector, portion of a hyperboloide, rotating around its axis SY, inclined at an angle α relative to the focal axis OX of the system, but whose apex S is located on the focal axis OX.

Ce réflecteur est entraîné en rotation par un moteur schématisé par M. La rotation du réflecteur auxiliaire 4, incliné par rapport à l'axe focal du système permet à la réception de faire un balayage conique. Le foyer F1 du réflecteur hyperbolique 4 décrit un cercle de centre F, foyer du réflecteur principal et du premier réflecteur auxiliaire 3, dans la plan focal P. Le diagramme de rayonnement 3. la réception DR, visible figure 2, tourne autour de l'axe focal OX du système avec un niveau de recoupement des lobes sur l'axe, défini par l'angle d'inclinaison α de l'axe SY par rapport à l'axe OX.This reflector is rotated by a motor shown schematically by M. The rotation of the auxiliary reflector 4, inclined relative to the focal axis of the system allows reception to make a conical scan. The focal point F1 of the hyperbolic reflector 4 describes a center circle F, focal point of the main reflector and of the first auxiliary reflector 3, in the focal plane P. The radiation diagram 3. the reception DR, visible in FIG. 2, revolves around the OX focal axis of the system with a level of overlap of the lobes on the axis, defined by the angle of inclination α of the axis SY relative to the axis OX.

Sur cette figure 2 on a également représenté le diagramme de rayonnement à l'émission DE qui est fixe et centré sur l'axe du système. On y a figuré aussi l'axe du lobe AL et la direction DC dans laquelle se trouve la cible.This FIG. 2 also shows the radiation diagram for the emission DE which is fixed and centered on the axis of the system. Also included was the axis of the AL lobe and the DC direction in which the target is located.

On a représenté sur la figure 1, le trajet d'une onde émise en trait plein et celui d'une onde réfléchie en traits interrompus.FIG. 1 shows the path of a wave emitted in solid lines and that of a wave reflected in broken lines.

On notera que les fils parallèles constituant le réflecteur auxiliaire hyperbolique 3 utilisé à l'émission sont de dimensions relativement petites suivant la bande de fréquence de fonctionnement de l'antenne. En bande Ku par exemple, les fils ont un diamètre de l'ordre de 0,12 au pas 0,6 et le diamètre du réflecteur ne dépasse pas 110 cm, avec une focale de l'ordre de 171 cm. Du point de vue mécanique, les fils sont supportés soit par une structure dite sandwich soit par une peau unique auto-adaptée.It will be noted that the parallel wires constituting the hyperbolic auxiliary reflector 3 used for transmission are of relatively small dimensions depending on the operating frequency band of the antenna. In the Ku band for example, the wires have a diameter of the order of 0.12 in step 0.6 and the diameter of the reflector does not exceed 110 cm, with a focal length of the order of 171 cm. From the mechanical point of view, the wires are supported either by a so-called sandwich structure or by a single self-adapted skin.

De façon préférentielle, suivant la distance à laquelle doit 3e trouver le second réflecteur auxiliaire hyperbolique du premier, il faut choisir la structure qui présente le moins d'épaisseur, de façon que la rotation du second réflecteur ne soit pas gênée. Si l'on utilise une peau auto-adaptée, il faut prévoir des compensations, en général un réseau de fils orthogonaux aux premiers qui sont choisis tels qu'ils ne provoquent pas de pertubations à la réception.Preferably, according to the distance at which 3 e must find the second auxiliary hyperbolic reflector of the first, it is necessary to choose the structure which has the least thickness, so that the rotation of the second reflector is not hampered. If a self-adjusting skin is used, compensations must be provided, in general a network of wires orthogonal to the first ones which are chosen such that they do not cause disturbances on reception.

Le réflecteur auxiliaire tournant 4, dans un exemple de réalisation a un diamètre de l'ordre de 95 cm et une focale de 171 cm, alors que le réflecteur principal a un diamètre de l'ordre de 800 cm et une focale de 255 cm.The rotating auxiliary reflector 4, in an exemplary embodiment has a diameter of the order of 95 cm and a focal length of 171 cm, while the main reflector has a diameter of the order of 800 cm and a focal length of 255 cm.

La figure 3 présente un diagramme schématique d'un radar à balayage conique utilisant le système d'antenne qui a été décrit. Ce diagramme classique ne sera pas décrit en détail.FIG. 3 presents a schematic diagram of a conical scanning radar using the antenna system which has been described. This classic diagram will not be described in detail.

A partir de l'antenne de la figure 1, on trouve la source primaire 2 connectée d'une part à l'émetteur 10 alimenté par le générateur de synchronisation 11, et d'autre part par l'intermédiaire du TR 9 à la partie réception comportant un circuit mélangeur 12 connecté au générateur 13 de l'oscillateur local et à un amplificateur à fréquence intermédiaire 14 suivi d'un détecteur 15. Cet amplificateur est connecté à un circuit 16 de commande automatique du gain connecté au circuit 17 de sélection de la distance. Ce circuit est alimenté par le circuit 18 de poursuite en distance connecté au générateur de synchronisation 11. Le circuit de sélection de la distance 17 est connecté au circuit 18 de démodulation en gisement et au circuit 20 de démodulation en site, qui reçoivent, une information de référence gisement et site respectivement du moteur d'entraînement M du réflecteur auxiliaire hyperbolique 4 de l'antenne par l'intermédiaire d'un circuit 25. Ces circuits déterminent les erreurs en gisement et en site qu'ils envoient aux servomécanismes de gisement 21 et de site 22 qui alimentent respectivement des moteurs 23 et 24 agissant pour ramener l'axe de l'antenne sur la cible.From the antenna of FIG. 1, there is the primary source 2 connected on the one hand to the transmitter 10 supplied by the synchronization generator 11, and on the other hand via the TR 9 to the reception part comprising a mixer circuit 12 connected to the generator 13 of the local oscillator and to an intermediate frequency amplifier 14 followed by a detector 15. This amplifier is connected to a circuit 16 for automatic gain control connected to the selection circuit 17 from the distance. This circuit is supplied by the distance tracking circuit 18 connected to the synchronization generator 11. The distance selection circuit 17 is connected to the field demodulation circuit 18 and to the site demodulation circuit 20, which receive information reference point and site respectively of the drive motor M of the hyperbolic auxiliary reflector 4 of the antenna via a circuit 25. These circuits determine the errors in field and site which they send to the field servomechanisms 21 and of site 22 which respectively feed motors 23 and 24 acting to bring the axis of the antenna back to the target.

On a ainsi décrit un système d'antenne à balayage conique pour radar de poursuite dans lequel, l'antenne du type Cassegrain, émet suivant un diagramme de rayonnement centré sur l'axe et reçoit suivant un balayage conique, une onde réfléchie dépolarisée. Une telle antenne, équipant un radar de poursuite présente des avantages qui ont été signalés au début de la description, en particulier, impossi- bilité de déterminer la fréquence de rotation du diagramme à balayage conique. Un autre avantage est la non perturbation du fonctionnement du radar dans de mauvaises conditions atmosphériques, due au fait que les gouttes de pluie par exemple sont très peu dépolarisantes.We have thus described a conical scanning antenna system for tracking radar in which, the Cassegrain type antenna, emits according to a radiation diagram centered on the axis and receives according to a conical scanning, a depolarized reflected wave. Such an antenna, fitted to a tracking radar has advantages that have been reported at the beginning of the description, in particular, p im ossi- bility to determine the rotational frequency of the conical scan pattern. Another advantage is the non-disturbance of the operation of the radar in bad atmospheric conditions, due to the fact that the rain drops for example are very little depolarizing.

Claims (11)

1. Système d'antenne à balayage conique pour radar de poursuite, du type antenne Cassegrain comportant un réflecteur principal, portion d'un paraboloïde de révolution et un réflecteur auxiliaire, portion d'un hyperboloide de révolution, caractérisé par le fait que le système d'antenne comporte deux réflecteurs auxiliaires, portions d'hyperboloides de révolution, l'un de ces réflecteurs étant entraîné en rotation par rapport à l'autre et par rapport au réflecteur principal.1. Conical scanning antenna system for tracking radar, of the Cassegrain antenna type comprising a main reflector, portion of a paraboloid of revolution and an auxiliary reflector, portion of a hyperboloide of revolution, characterized in that the system antenna comprises two auxiliary reflectors, portions of hyperboloids of revolution, one of these reflectors being driven in rotation relative to the other and relative to the main reflector. 2. Système d'antenne à balayage conique suivant la revendication 1, caractérisé par le fait que le réflecteur auxiliaire hyperbolique tournant, appelé second réflecteur auxiliaire a son axe de révolution incliné par rapport à l'axe focal du système et son sommet fixe sur l'axe focal du système.2. conical scanning antenna system according to claim 1, characterized in that the auxiliary hyperbolic rotating reflector, called second auxiliary reflector has its axis of revolution inclined relative to the focal axis of the system and its fixed apex on the focal point of the system. 3. Système d'antenne à balayage conique suivant la revendication 1, caractérisé par le fait que le premier réflecteur hyperbolique est disposé entre le réflecteur principal et le second réflecteur auxiliaire et qu'il est constitué par un réseau de fils conducteurs parallèles au vecteur polarisation de l'onde émise.3. conical scanning antenna system according to claim 1, characterized in that the first hyperbolic reflector is arranged between the main reflector and the second auxiliary reflector and that it is constituted by a network of conducting wires parallel to the polarization vector of the wave emitted. 4. Système d'antenne à balayage conique suivant la revendication 1, caractérisé par le fait que le foyer F du réflecteur principal parabolique situé sur l'axe focal du système, est également le foyer du premier réflecteur auxiliaire, que le second foyer du premier réflecteur auxiliaire est confondu avec le centre de phase de la source primaire, que le premier foyer du second réflecteur auxiliaire se trouve dans le plan focal du réflecteur principal et du premier réflecteur auxiliaire et que le second foyer du second réflecteur auxiliaire se trouve dans le second plan focal du premier réflecteur auxiliaire.4. conical scanning antenna system according to claim 1, characterized in that the focus F of the parabolic main reflector located on the focal axis of the system, is also the focus of the first auxiliary reflector, that the second focus of the first auxiliary reflector coincides with the phase center of the primary source, that the first focus of the second auxiliary reflector is in the focal plane of the main reflector and of the first reflector auxiliary and that the second focus of the second auxiliary reflector is in the second focal plane of the first auxiliary reflector. 5. Système d'antenne à balayage conique suivant la revendication 3, caractérisé par le fait que le premier réflecteur auxiliaire est constitué par un réseau de fils parallèles supportés par une structure sandwich.5. A conical scanning antenna system according to claim 3, characterized in that the first auxiliary reflector is constituted by a network of parallel wires supported by a sandwich structure. 6. Système d'antenne à balayage conique suivant la revendication 3, caractérisé par le fait que le premier réflecteur auxiliaire est constitué par un réseau de fils parallèles par une peau unique auto-adaptée.6. conical scanning antenna system according to claim 3, characterized in that the first auxiliary reflector is constituted by a network of parallel wires by a single self-adapted skin. 7. Système d'antenne à balayage conique suivant la revendication 1, caractérisé par le fait que les cibles poursuivies étaient dépolarisantes, le diagramme de rayonnement à balayage conique est utilisé à la réception seulement, le diagramme à l'émission étant fixe et centré sur l'axe focal du système.7. conical scanning antenna system according to claim 1, characterized in that the targets pursued were depolarizing, the conical scanning radiation diagram is used at reception only, the emission diagram being fixed and centered on the focal axis of the system. 8. Système d'antenne à balayage conique suivant la revendication 1, caractérisé par le fait qu'il comporte une source primaire capable de rayonner des ondes ayant des vecteurs polarisation rectiligne orthogonaux.8. A conical scanning antenna system according to claim 1, characterized in that it comprises a primary source capable of radiating waves having orthogonal rectilinear polarization vectors. 9. Système d'antenne à balayage conique suivant la revendication 8, caractérisé par le fait que la source primaire est constituée par un guide de section circulaire terminé par un cornet, alimenté par deux guides à section rectangulaire, orthogonaux formant séparateur de polarisation.9. A conical scanning antenna system according to claim 8, characterized in that the primary source consists of a guide of circular section terminated by a horn, supplied by two guides of rectangular section, orthogonal forming polarization splitter. 10. Système d'antenne à balayage conique suivant la revendication 8, caractérisé par le fait que la source primaire est un cornet rainuré.10. A conical scanning antenna system according to claim 8, characterized in that the primary source is a grooved horn. 11. Système d'antenne à balayage conique suivant la revendication 8, caractérisé par le fait que la source primaire est un cornet bimode.11. A conical scanning antenna system according to claim 8, characterized in that the primary source is a dual-mode horn.
EP78400242A 1977-12-22 1978-12-15 Conical scan antenna for tracking radar Ceased EP0002982A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7738826 1977-12-22
FR7738826A FR2412961A1 (en) 1977-12-22 1977-12-22 CONICAL SCAN ANTENNA SYSTEM FOR TRACKING RADAR

Publications (1)

Publication Number Publication Date
EP0002982A1 true EP0002982A1 (en) 1979-07-11

Family

ID=9199213

Family Applications (1)

Application Number Title Priority Date Filing Date
EP78400242A Ceased EP0002982A1 (en) 1977-12-22 1978-12-15 Conical scan antenna for tracking radar

Country Status (3)

Country Link
US (1) US4305075A (en)
EP (1) EP0002982A1 (en)
FR (1) FR2412961A1 (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2596208A1 (en) * 1986-03-19 1987-09-25 Europ Agence Spatiale Two-frequency antenna with independent steerable beams
FR2601195A1 (en) * 1986-07-04 1988-01-08 Europ Agence Spatiale LARGE SCAN ANTENNA WITH MAIN REFLECTOR AND FIXED SOURCES, IN PARTICULAR FOR USE IN MICROWAVE, ON SATELLITE, AND SATELLITE EQUIPPED WITH SUCH ANTENNA
EP0466579A1 (en) * 1990-07-11 1992-01-15 AEROSPATIALE Société Nationale Industrielle Double reflector with grids
AU627493B2 (en) * 1988-09-23 1992-08-27 Alcatel N.V. A circularly symmetrical reflector
EP0507440A1 (en) * 1991-02-25 1992-10-07 Gerald Alexander Bayne Antenna
EP0514886A1 (en) * 1991-05-23 1992-11-25 Hughes Aircraft Company Dual reflector scanning antenna system
EP2099095A1 (en) 2008-03-06 2009-09-09 Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) Device for two-dimensional imaging of scenes using microwaves

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2238430B (en) * 1985-10-02 1991-10-16 British Aerospace Microwave and millimetric waveband receivers
US5077560A (en) * 1986-02-19 1991-12-31 Sts Enterprises, Inc. Automatic drive for a TVRO antenna
DE19544500C2 (en) * 1994-12-15 1999-07-08 Daimler Benz Aerospace Ag Reflector antenna, in particular for a communication satellite
US5485168A (en) * 1994-12-21 1996-01-16 Electrospace Systems, Inc. Multiband satellite communication antenna system with retractable subreflector
DE29724409U1 (en) * 1997-10-14 2001-11-15 Rr Elektronische Geraete Gmbh Tracking system for aligning a swiveling reflective antenna
FR2770650A1 (en) * 1997-10-30 1999-05-07 Aerospatiale OPTICAL SYSTEM WITH MULTIPLE SIGHT LINES
DE19952819A1 (en) * 1999-11-02 2001-07-12 Rr Elektronische Geraete Gmbh Reflector antenna and method of manufacturing a sub-reflector
US6917287B2 (en) * 2000-11-10 2005-07-12 Michelin Recherche Et Technique S.A. System for monitoring the tires of a vehicle, comprising a device for automatic location of wheel transmitters
US20020186813A1 (en) * 2001-05-08 2002-12-12 Toshikazu Tamura Image sensing apparatus and image sensing method, X-ray photographing system and its control method
US6512486B1 (en) * 2001-10-09 2003-01-28 The Boeing Company Monopulse beam pointing system for a satellite communication system
US6680711B2 (en) * 2002-01-08 2004-01-20 The Boeing Company Coincident transmit-receive beams plus conical scanned monopulse receive beam
DE112005000876B4 (en) * 2004-05-21 2010-06-10 Murata Manufacturing Co., Ltd., Nagaokakyo Antenna device and radar device comprising the same
US20050280593A1 (en) * 2004-06-22 2005-12-22 Seung-Hyeon Cha Satellite tracking antenna and method using rotation of a subreflector
KR100721559B1 (en) * 2005-12-08 2007-05-23 한국전자통신연구원 A conical scanning antenna system using nutation method
US8334815B2 (en) * 2009-07-20 2012-12-18 Kvh Industries, Inc. Multi-feed antenna system for satellite communications
CN103579761B (en) * 2013-10-29 2016-09-07 常州工学院 A kind of optical mechaical scanning antenna assembly of scanning imagery application
GB2534555A (en) 2015-01-20 2016-08-03 Kathrein Werke Kg Method and system for the automated alignment of antennas
CN117687018B (en) * 2024-01-31 2024-04-19 四川省华盾防务科技股份有限公司 Phased array beam tracking method, device, system and storage medium

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1257630A (en) * 1957-05-14 1961-04-07 Csf Double aerial for radar
US3281850A (en) * 1962-03-07 1966-10-25 Hazeltine Research Inc Double-feed antennas operating with waves of two frequencies of the same polarization
DE1937583A1 (en) * 1969-07-24 1972-03-30 North American Rockwell Multiple antenna
US3696432A (en) * 1971-01-15 1972-10-03 Motorola Inc Combined scan and track antennas

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2877354A (en) * 1953-08-14 1959-03-10 North American Aviation Inc Radiation tracker for aiming at center or centroid of multiple targets
FR1192907A (en) * 1955-04-06 1959-10-29 Electronique & Physique Improvements to space exploration systems associated with radiation detectors
US3307183A (en) * 1957-03-11 1967-02-28 Boeing Co Conical scan radar system and antenna
US3866233A (en) * 1973-09-10 1975-02-11 Nasa Dish antenna having switchable beamwidth
US4042933A (en) * 1976-03-19 1977-08-16 The United States Of America As Represented By The Secretary Of The Navy Antenna line scan system for helicopter wire detection
US4041500A (en) * 1976-05-12 1977-08-09 The United States Of America As Represented By The Secretary Of The Navy Line scan radar antenna using a single motor

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1257630A (en) * 1957-05-14 1961-04-07 Csf Double aerial for radar
US3281850A (en) * 1962-03-07 1966-10-25 Hazeltine Research Inc Double-feed antennas operating with waves of two frequencies of the same polarization
DE1937583A1 (en) * 1969-07-24 1972-03-30 North American Rockwell Multiple antenna
US3696432A (en) * 1971-01-15 1972-10-03 Motorola Inc Combined scan and track antennas

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2596208A1 (en) * 1986-03-19 1987-09-25 Europ Agence Spatiale Two-frequency antenna with independent steerable beams
FR2601195A1 (en) * 1986-07-04 1988-01-08 Europ Agence Spatiale LARGE SCAN ANTENNA WITH MAIN REFLECTOR AND FIXED SOURCES, IN PARTICULAR FOR USE IN MICROWAVE, ON SATELLITE, AND SATELLITE EQUIPPED WITH SUCH ANTENNA
US4814778A (en) * 1986-07-04 1989-03-21 Agence Spatiale Europeenne Large scan antenna with fixed main reflector and fixed feed, particularly for use at ultrahigh frequencies, carried on board a satellite and a satellite equipped with such an antenna
AU627493B2 (en) * 1988-09-23 1992-08-27 Alcatel N.V. A circularly symmetrical reflector
EP0466579A1 (en) * 1990-07-11 1992-01-15 AEROSPATIALE Société Nationale Industrielle Double reflector with grids
FR2664750A1 (en) * 1990-07-11 1992-01-17 Aerospatiale GRILLE BIREFLECTOR.
EP0507440A1 (en) * 1991-02-25 1992-10-07 Gerald Alexander Bayne Antenna
US5351060A (en) * 1991-02-25 1994-09-27 Bayne Gerald A Antenna
EP0514886A1 (en) * 1991-05-23 1992-11-25 Hughes Aircraft Company Dual reflector scanning antenna system
EP2099095A1 (en) 2008-03-06 2009-09-09 Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) Device for two-dimensional imaging of scenes using microwaves
DE102008013066B3 (en) * 2008-03-06 2009-10-01 Deutsches Zentrum für Luft- und Raumfahrt e.V. Device for two-dimensional imaging of scenes by microwave scanning and use of the device
US8009116B2 (en) 2008-03-06 2011-08-30 Deutsches Zentrum für Luft- und Raumfahrt e.V. Device for two-dimensional imaging of scenes by microwave scanning

Also Published As

Publication number Publication date
US4305075A (en) 1981-12-08
FR2412961B1 (en) 1981-08-28
FR2412961A1 (en) 1979-07-20

Similar Documents

Publication Publication Date Title
EP0002982A1 (en) Conical scan antenna for tracking radar
FR2501868A1 (en) APPARATUS FOR DETERMINING THE PRESENCE OF MULTIPLE REFLECTION CONDITIONS DURING TARGET PURSUIT USING RADAR
FR2740878A1 (en) BEAM ORIENTATION CONTROL FOR TELEMETRIC SYSTEM
EP0656671A1 (en) Orientable antenna with maintenance of the polarisations axes
EP0013221B1 (en) Radar scanning antenna, in particular for a tracking radar
EP2122388A1 (en) Device and method for locating a mobile approaching a surface reflecting electromagnetic waves
WO2013144146A1 (en) Device for active and passive electromagnetic detection with a low likelihood of interception
FR2648570A1 (en) DEVICE AND METHOD FOR MEASURING THE AZIMUT AND THE SITE OF AN OBJECT
US5874917A (en) Method and apparatus for extracting target information from a radar signal
CA2063017C (en) Method and device for determining an antenna radiation pattern
EP0197944A1 (en) Antenna tracking system using sequential lobing.
US3883876A (en) High frequency radiometric target seeking and tracking apparatus
FR2778043A1 (en) Orbitting satellite transmitter/receiver tracker
EP0237404A1 (en) Method of processing sum and difference signals in a monopulse radar for estimating the parasitic phase between these signals caused by the HF circuits forming sum and difference channels
EP1107019A1 (en) Radar system and method for searching in azimuth
FR2578058A1 (en) METHOD AND DEVICE FOR PURSUING A COMMUNICATION SATELLITE
GB2031655A (en) Dual beam antenna system
FR2986334A1 (en) Radar i.e. X band synthetic aperture radar instrument, for use on carrier satellite for maritime surveillance mission, has selection unit to select instrument between small swath mode and large swath mode to allow ambiguous zone observation
EP3904904B1 (en) Monitoring of space by means of a bistatic radar in which the receiver system is at least partially on board a satellite
FR2624981A1 (en) Radionavigation device and method for aircraft with rotors
EP3654057B1 (en) Method for optimising the pointing of an antenna of an airborne radar system
BE510391A (en)
FR2520511A1 (en) Automatic radio location and monitoring Doppler receiver system - includes amplitude and phase comparator with processing circuit to calculate azimuth angle as function of phase differences
FR2714975A1 (en) Guidance radar system with difference beams
EP0624804A1 (en) Tracking system for estimating the pointing error of a HF antenna

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): CH DE GB IT NL SE

17P Request for examination filed
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED

18R Application refused

Effective date: 19820507

RIN1 Information on inventor provided before grant (corrected)

Inventor name: SALVAT, FRANCOIS

Inventor name: BOUKO, JEAN