FR2589633A1 - Active type aiming antenna - Google Patents

Abstract

The present invention relates to an aiming antenna comprising a radome 19, a parabola 10 and means of moving this parabola so as to aim it in the direction of a geostationary satellite. The parabola 10 is supported by a cradle 12 by means of two articulations 11, the cradle 12 being carried by a pivot 28 integral with a support structure 13. The radome 19 includes a dome 20 and a base 21. A circular rail 18 is mounted inside the base 21. The support structure includes an annular element 14 provided with idlers 15 and 16 arranged so as to roll over the rail 18. A drive motor 43 provides for the azimuthal motion of the antenna. Two identical motors bring about, by means of a cable 47, the pivoting of the cradle 12 with respect to the support structure and the pivoting of the parabola 10 with respect to the cradle 12. This antenna is advantageous by reason of its low weight, cost and bulk.

Description

POINTING ANTENNA OF THE ACTIVE TYPE
The present invention relates to an active type pointing device comprising a parabola mounted on a mobile support and protected by a fixed radome.

There are currently two types of pointing antennas: so-called passive antennas and so-called active antennas. The first consist of a stabilization mechanism, for example of the gyroscopic type, comprising from 2 to 4 rotating gyroscopes and a central support carrying the pointing antenna proper. They generally represent heavy and bulky units attached to the top of a mdt which must necessarily be of very robust construction to support this set. As a result, they can only equip heavy vehicles, in particular large tonnage boats. The central support generally carries a rotating platform which carries the axis of rotation of the parabola constituting the antenna proper. To be able to scan all the space, the span of the system is relatively large, so that the size of the protective radome is very large. Another drawback of these systems is due to the fact that the stabilization mechanism can easily be destabilized by lateral accelerations of a certain importance. The return to stable state is long, it can last Up to 15 minutes.

Finally, access to the antenna for an overhaul, repair or maintenance operation is often made laborious by the presence of the stabilization mechanism, placed below the antenna, which hinders this access.

The seconds include drive motors controlled by an electronic device which receives information from a small gyroscope separate from the antenna. The relatively heavy and bulky drive motors, as well as a complicated construction, make the current systems expensive and unsuitable for certain applications, in particular use on road vehicles, installation on small tonnage boats, etc. .. In addition, these known systems are sensitive to vibrations, in particular if their frequency is such that they generate resonance phenomena.

The present invention proposes to overcome these drawbacks by producing an antenna of the active type, of simple, light, economical design, easy to access and the routine maintenance of which can be assumed without problem.

For this purpose, the pointing antenna according to the invention is characterized in that the radome consists of an upper part or dome and a lower part or base, these two parts being connected to each other by a circular belt, in that the base is fixed and carries at least one fixed circular rail rigidly mounted inside this base, in that the parabola is fixed by means of two articulations to a cradle pivoting on a structure support, and in that the support structure is arranged to roll on said fixed circular rail.

According to a particular embodiment of the antenna according to the invention, the base carries a single rail and the support structure comprises a circular crown segment carrying a first and a second series of rollers, these rollers being respectively interconnected by a rigid flange and arranged to roll respectively on the upper edge and on the lower edge of the fixed circular rail.

In this case, said support structure advantageously comprises a transverse bar the ends of which are fixed to said circular crown segment and two pairs of feet connected in pairs by their upper end to a connecting piece carrying a pivot on which said cradle is mounted and fixed at their lower ends, respectively to the crossbar and to the circular crown segment.

According to another embodiment of the antenna according to the invention, the base carries a first and a second circular rail, the first rail forming the raceway for support rollers and the second rail serving as a guide with two follower rollers, the support rollers being in support respectively on the upper edge and on the lower edge of the first rail and the follower rollers being respectively in abutment against the internal face and the external face of the second rail.

In this case, the support structure advantageously comprises a support carrying all of these rollers and two arms fixed to the support and retained by lateral tie rods.

According to a preferred embodiment, the cradle comprises a plate in the form of a half-moon carried by a pivot secured to the support structure and equipped with two articulations arranged to connect the parabola to said cradle.

Each articulation advantageously comprises a first element secured to a pulley and a second element carrying the axis of the pulley, this pulley being able to be driven in one direction or the other in rotation about its axis.

To carry out the displacements of the parabola, the antenna according to the invention preferably comprises a first drive motor carrying a drive pulley and a cable enclosing said fixed circular rail and passing over said drive pulley, so as to rolling said support structure on said rail. This motor drives the azimuth of said antenna.

To rotate the parabola with respect to the cradle and the cradle with respect to the support structure, the antenna includes two other motors carrying respectively two drive pulleys, these motors being identical and capable of driving said pulleys at the same speed in the same speed opposite or opposite direction and a cable forming a closed loop passing successively on a driving pulley, on one of the pulleys of one of the joints, on the other driving pulley and, after crossing, on the other pulley of the other joint connecting the dish to the cradle.

To guide this cable, the antenna preferably has two circular sectors arranged on either side of the half-moon shaped plate, these sectors being each mounted on a connecting element by means of a pivot axis, the cable being guided by the outer edge of these circular sectors.

The pivot of the cradle is preferably located substantially in the center of the radome, which advantageously makes it possible to reduce the size of the antenna according to the invention.

To allow access to maintenance personnel, the radome base has a flat bottom provided with an access opening.

The antenna according to the invention is advantageously equipped with a gyroscope associated with a magnetic compass.

According to a particular embodiment, the antenna according to the invention is fixed to the top of a tubular mast.

The present invention will be better understood with reference to the description of embodiments and the accompanying drawing in which
FIG. 1 represents a perspective view of a first embodiment of the antenna according to the invention more particularly illustrating the drive mechanism ensuring the displacements of the parabola,
FIG. 2 represents a view in section and in elevation of the antenna according to FIG. 1,
FIG. 3 represents a partially cut plan view of the antenna illustrated by FIGS. 1 and 2,
FIG. 4 represents a partially sectioned elevation view of another embodiment of the antenna according to the invention,
FIG. 5 represents a view partially cut in plan of the antenna illustrated by FIG. 4.

FIG. 6 schematically represents an embodiment of the support of the antenna according to the invention,
FIG. 7 represents a variant of this support,
FIGS. 8 and 9 illustrate two particular applications of the antenna according to the invention, and
FIG. 10 represents a detail view of the gyroscope combined with a magnetic compass associated with the antenna according to the invention.

With reference to FIGS. 1 to 3, the pointing antenna according to the invention tiob comprises a parabola 10 whose axis is intended to be oriented permanently in the direction of a geostationary satellite. For this purpose, this parabola is linked to two articulations 11 integral with the end of a cradle 12, carried by a support structure, for example tubular 13, mounted on a segment of circular crown 14, these different components being movable one relative to the others and relative to a fixed part to allow the movement of the antenna in all planes. The ring segment 14 is equipped with two series of rollers 15 and 16 connected two by two by a rigid flange 17 and arranged for rolling respectively on the upper edge and on the lower edge of a fixed circular rail 18.

All this assembly is housed inside a protective radome 19 which consists of an upper part or pole 20 and a lower part or base 21, these two parts being fixed to each other at the by means of a circular belt 22 having for example an H-shaped profile. The base has a flat bottom surface 23 allowing its attachment to the top of a mast or on any surface of any vehicle, and which is provided with a service opening 24. The support elements 25 are mounted inside the base 21 to carry the circular rail 18.

The cradle 12 has a half-moon shaped plate 26 and a diametrical reinforcement bar 27 provided with a housing for a pivot 28.

This pivot is carried by two symmetrical pieces 29 each of which is integral with the upper end of a first leg 30 whose base is fixed to a transverse bar 31 connected at its two ends to the circular crown segment 14, and of a second leg 32 whose base is fixed to the upper surface of this segment. The two feet 30 and the two feet 32 constitute, with said parts 29, said tubular support 13.

The joints 11 consist of a first element 33 secured to a pulley 34 whose axis 35 is carried by a second element 36 carried by the diametrical reinforcement bar 27 of the half-moon shaped plate 26. The rotation of the pulleys 34 around their axis makes it possible to orient the parabola with respect to the plane of the cradle 12, this plane being defined by the plate in the shape of a half-moon 26.

The two symmetrical pieces 29 each further carry a temeat axis 37 on which two circular sectors 38 can pivot, the role of which will be defined below. A shock absorber 39 of the movement of the two circular sectors is fixed between them, in such a way that the body 40 of the shock absorber is linked to the first sector and the piston rod 41 of this shock absorber is linked, directly or by means a link (not shown), to the other sector. A suitable opening 42 is made in the plate 26 in the form of a half-moon to provide the necessary clearance for the displacement of the damper 110.

To allow the rotation of the support of the cradle of the parabola, that is to say to ensure the azimuth movement of the antenna, the circular ring segment 14 rolls by means of its rollers 15 and 16 on the circular rail 18. This movement is ensured by a motor 43 whose output axis carries a drive pulley 44 which can be driven in one direction or the other. A non-extensible flexible belt or cable 45, deflected by two lateral guide pulleys 46 passes over the drive pulley 44 and bears against the peripheral wall of the fixed circular rail 18.

To allow the pivoting of the cradle 12 around the axis of the pivot 28 and the pivoting of the parabola around the axes 35 of the pulleys 34, use is made of a cable 47 forming a closed loop which follows the path shown in FIG. 1. Two identical motors 48 (shown in solid lines) and 49 (shown in broken lines) each carry a driving pulley 50 and 51 respectively. The cable 47 passes first of all over the driving pulley 50, is deflected by a lateral pulley guide 52, then rests against the peripheral edge of one of the two circular sectors 38. it then passes over a first guide roller 53 then on one of the pulleys 34, on a second guide roller 53, these two rollers being fixed to the half-moon shaped plate 26, and rests on the outer edge of the other circular sector 38 before passing over the second drive pulley 51 after having been deflected by a lateral guide pulley 54 .After its passage on the driving pulley 51, the cable is deflected by another guide pulley 54 arranged symmetrically with respect to the previous one, again takes support on the peripheral edge of said circular sector 38, passes over a first roller 53 ', on a second 53 '' roller, after crossing, on the second pulley 34, on another roller 53 "then on the second roller 53 ', bears on the peripheral edge of the first circular sector 38 and returns, after having been deflected by a second lateral guide pulley 52, on the driving pulley 50.

The two motors 48 and 49 are identical and can be driven at the same speed independently in one direction and in the other. When the two drive pulleys 50 and 51 are driven in the same direction, at the same speed, the cradle pivots around the pivot 28. This pivoting can be done in one direction or the other depending on the direction of rotation of the drive pulleys 50 and 51. In this case, it is therefore the entire cradle which pivots, the parabola remaining stationary relative to this cradle.

When the two drive pulleys 50 and 51 are driven in opposite directions, at the same speed, the cradle remains stationary, but the two pulleys 34 are driven simultaneously in rotation, which has the effect of rotating the parabola relative to the cradle. For example, when the driving pulley 50 turns clockwise and the driving pulley 51 in the opposite direction, the pulleys 34 rotate simultaneously in a clockwise direction and rotate the parabola in the direction of arrow A. When the driving pulley 5G rotates counterclockwise and the pulley 51 rotates clockwise, the pulleys 34 rotate simultaneously in the opposite direction to the needles of a watch and the satellite dish rotates in the direction of the arrow
B, the cradle remaining stationary on its support.

An electronic control unit 55 controls the various motors responsible for the movement of the various components of the antenna. A connection box 56, connected to the antenna by a cable 57, makes it possible to transmit the signals picked up by this antenna to a suitable receiver (not shown).

A gyroscope 56, possibly associated, as shown in FIG. 10, with a magnetic compass 59, can be mounted under the bottom 23 of the radome 19.

Figures 4 and 5 show another embodiment of the pointing antenna of Figures 1 to 3. Since many construction elements already described with reference to Figures 1 to 3 are found in the embodiment corresponding to Figures 4 and 5, the same reference numbers of identical elements will be used. In fact, the two embodiments differ essentially by the embodiment of the support structure of the dish and by the arrangement of the circular rail allowing the azimuth movement of the antenna to be carried out.

In this exemplary embodiment, the base 21 of the radome carries a first circular rail 18a and a second circular rail 18b, the first forming the raceway of two pairs of rollers 15a and 16a and the second serving as a guide member to two follower rollers 60, respectively bearing against the inner face and the outer face of the rail 18b. A support 61 carries the two pairs of rollers 15a and 16a as well as the follower rollers 60. This support also carries the drive motor 43 responsible for the azimuth movement of the parabola as well as the housing 55 containing the electronic circuit for controlling the motors of displacement of the parabola.

The support of the cradle 12 consists of two arms 62, fixed at 63 to the support 61 and retained in position by two lateral tie rods 64.

The pivoting of the parabola relative to the cradle 12 and the pivoting of the cradle around the pivot 28 are generated as before by a cable 47 driven by two motors 48 and 49 respectively fixed to the two arms 62. The azimuth movement is controlled by a belt or cable 45a which surrounds, as before, the circular rail 18a.

FIG. 6 more particularly illustrates an embodiment of a mast serving as a support for the pointing antenna described above.

According to this embodiment, the radome 19 is fixed at the top of a tubular mast 70 provided with a maintenance platform 71 and fixed at the top of a tubular structure 72 provided with an access ladder 73. The opening 24 , formed at the base of the radome, can be closed off by a hatch 74 which allows access by a person 75, responsible for maintenance, to the various components of the pointing antenna. The mast 70 is advantageously made by means of segments 70galet 70b in the form of a quarter cylinder, assembled along their edges by means of bolts 76 and 77, or rivets or the like. In this way, the antenna and mast assembly can be packed in a box whose dimensions hardly exceed those of the radome. This is a great advantage when storing and transporting this material.

FIG. 7 illustrates a variant of the device illustrated in FIG.

6. A mast 80 of reduced size compared to the base of the. radome 19 carries, in the vicinity of its upper end, a structure 81 retaining a platform 82 accessible by steps 83 and allowing maintenance personnel 84 to access, through the opening 24 provided at the bottom of the radome and susceptible of be closed by a hatch 85, to the components of the pointing antenna.

FIG. 8 illustrates a particular application of the pointing antenna. described above, housed in a radome 19 fixed on the roof of a cabin 90 of a yacht 91 of relatively small tonnage.

FIG. 9 illustrates another use of an antenna, as described, housed inside a radome 19 fixed on the roof of a road vehicle 92, for example an all-terrain vehicle.

FIG. 10 illustrates the gyroscope 58 associated with a magnetic compass 59. We recall that a magnetic compass requires, for its operation, a support or table which remains constantly horizontal. The gyroscope comprises, in a manner known per se, a member 100 driven in rotation, mounted on an axis 101 carried by a frame 102. This frame is mounted, by means of two sections of axes 103a and 103b on a second frame 104 carried, by means of two sections of axes 105a and 105b on a support (not shown) secured to the road vehicle, the boat, etc. Two supports 106 secured to the frame 102 carry the compass table 59. This table , linked directly to the rotating member 100, remains constantly horizontal. Given that the antenna described, of the active type, is necessarily associated with a gyroscope, and that the use of a magnetic compass requires the provision of a horizontal base, the combination of these three elements becomes particularly advantageous, especially because of their small size.

The present invention is not limited to the embodiments described, but could undergo numerous modifications and be presented in various variants obvious to those skilled in the art. In particular, the geometry and construction of the cradle and its tubular support could be modified. However, the general concept, as defined in claim 1, remains unchanged in all of these variants.

Claims (14)

Claims  1. Pointing antenna of the active type, comprising a mounted satellite dish  on a mobile support and protected by a fixed radome, caradérisée en  what the radome consists of an upper or dome (20) and  a lower part or base (21), these two parts being connected  to each other by a circular belt (22), in that the base  is fixed and carries at least one fixed circular rail (18), rigidly mounted inside this base, in that the parabola is fixed by means of two articulations (11) to a cradle (12) pivoting on a support structure (13>, and in that the support structure is arranged to run on said fixed circular rail.  2. Antenna according to claim 1, characterized in that the base carries a single rail (18) and in that the support structure comprises  a circular crown segment (14) carrying a first series of rollers (15) and a second series of rollers (16), these rollers being  respectively connected to each other by a rigid flange (17) and arranged  to roll respectively on the upper edge and on the edge  lower of the fixed circular rail (18).  3. Antenna according to claim 2, characterized in that said  support structure comprises a transverse bar (31) the ends of which are fixed to said circular crown segment (14), two feet (30) and two feet (32) connected in pairs at their ends  superior to a connecting piece (29) carrying a pivot (28) on which is mounted said cradle (12), and fixed at their end  lower, respectively to the crossbar (31) and to the segment  circular crown (14).  Antenna according to claim 1, characterized in that the base  carries a first circular rail (18a) and a second circular rail  (18b), the first rail forming a raceway of two pairs  rollers (15a) and (16a), and the second serving as a guide member  two follower rollers (60), the rollers (15a) being supported on the edge  top of the rail (18a), the rollers (16a) being supported on the edge  bottom of rail 8a? and the rollers (60) being respectively in abutment against the internal face and the external face of the rail (18b). 5. Antenna according to claim 4, characterized in that the support structure comprises a support (61) carrying said rollers (15a, 16a and 60) and two arms (62) fixed to the support (61) and retained by two lateral tie rods ( 64). 6. Antenna according to claim 1, characterized in that the cradle (12) comprises a plate in the shape of a half-moon (26) carried by the pivot (28) and equipped with two articulations (11) arranged to connect the parabola ( 10) audit cradle. 7. Antenna according to claim 6, characterized in that each articulation (11) comprises a first element (33) integral with a pulley (34) and a second element (36) carrying the axis (35) of the pulley; this pulley can be driven in one direction or the other in rotation about its axis. 8. An antenna according to any one of the preceding claims, characterized in that it comprises a first drive motor (43) carrying a drive pulley (44) and a cable (45) enclosing said fixed circular rail (18 , 18a) and passing over said drive pulley, for rolling said support structure on said rail. 9. Antenna according to claim 8, characterized in that it comprises two other motors (48, 49) respectively carrying two drive pulleys (50, 51), these motors being identical and capable of driving said pulleys at the same speed in the same direction or in opposite direction, and a cable (47) forming a closed loop and passing successively on a driving pulley (50 or 51) on one of the pulleys (34) of a joint (11), on the other pulley drive (51 or 50), and, after crossing, on the other pulley (34) of the other joint 11). 10. Antenna according to claim 9, characterized in that it comprises two circular sectors (38) arranged on either side of the plate (26) in the form of a half-moon, these sectors being each mounted on an element of connection (29) by means of a pivot axis (37) and in that the cable (47) is guided by the outer edge of said circular sectors. 11. Antenna according to claim 10, characterized in that it comprises a damper (40) whose body (39) is fixed to one of the circular sectors t38) and whose piston head (41) is fixed to the 'other circular sector (38). 12. Antenna according to claim 1, characterized in that the pivot (28) of the cradle (12) is disposed substantially in the center of the radome (19). 13. Antenna according to claim 1, characterized in that the base (21) has a flat bottom t23) provided with an access opening (24). 14. Antenna according to claim 1, characterized in that it comprises a gyroscope (58) associated with a magnetic compass (59). 15. An antenna according to claim 1, characterized in that it is fixed to the top of a modular mast (70).