DE4009143A1 - Guiding system for projectiles using a directional beam coded in Cartesian coordinates - Google Patents

Abstract

The projectile guidance system transmits a directional beam encoded in Cartesian coordinates and includes a firing station (1) having means for tracking a target (2) and determining a sighting line (LV). Means for scanning a guide cone (5) by means of a laser beam (3) are provided. The symmetry axis (AS) of the traffic cone is readjusted to the sighting line (LV). This traffic cone is composed of elementary cells which are successively illuminated by the beam (3), which is deflected by two acousto-optic deflectors in two orthogonal planes. The beam (3) is modulated with a binary sequence representing the Cartesian coordinates (x, y) of the illuminated cell. The projectile (4) is provided with means for receiving the laser beam (3), demodulating it and decoding the polar coordinates. It also includes means for determining a trajectory correction by which the projectile is approximated to the axis of symmetry (AS) of the traffic cone.

Description

The The invention relates to a guidance system for projectiles under Use of a directional beam, in Cartesian or rectangular Coordinates is coded. These projectiles can missiles or grenades that are equipped with a device for trajectory correction are provided.

By Steering by means of a directional beam can be any number of Projectiles are directed very precisely against a target, without the position of each Projectile to determine by simply a sighting line is determined, which runs through the position to be reached, which is either the current target position or one future position is taken from the characteristics of its trajectory is determined. A target tracker determines this line of sight.

The Firing station sends an infrared laser beam, the one Room part illuminates, which is referred to as a traffic cone. The The position of the symmetry axis of the traffic cone is readjusted to the sighting line. The traffic cone consists of elementary cells that pass through individually a coding method can be identified. The projectile is with Equipped to receive and detect the beacon in which cell the projectile is located. Determine calculation means a correction of the trajectory of the projectile so that this approximates to the symmetry axis of the traffic cone. These Correction takes place by means of a tail or gas jets.

One Control system that works with a directional beam, stands out a high steering precision and good insensitivity to Interference measures, because the facilities for Receiving the beam, which in general to a lens and a detector optics are to the firing station towards and not directed to the goal.

There are two main types of guidance systems that work with a directional beam. In a first type, which employs so-called space coding, means are provided to emit a laser beam which simultaneously illuminates all of the elementary cells of the cone, each cell being identified by locally varying the amplitude of the laser beam for each cell binary codes is identified. The projectile determines which cell it is in by detecting this binary code which modulates the part of the beam received by the projectile. Such a system is in Optical Command and Beamrider Missile Guidance, RL Sitton, SPIE. Vol. 317, pp. 358-364 described.

a such system has the defect that a laser beam of relatively high power must be sent at the same time illuminate all the cells of the traffic cone, if a given range should be achieved. Any existing smoke and the flame and smoke of the projectile, if it is a missile, dampen the laser beam transmission between the firing station and the receiving devices for this beam in high Dimensions. Therefore, to achieve a given range, must be sent a beam having a sufficiently high spatial energy density has to compensate for this attenuation.

The second type of directivity beacon system is referred to as a time-coded or "sampling" system. The firing station sends a laser beam which illuminates a traffic cone by successively illuminating each of the elementary cells. In the article Michael Higgins, Gerald Titmuss, John Evans, Richard Martyn, British Aerospace UK "An improved acousto-optic laser scanner guidance system there is described a system wherein the firing station includes a continuous wave laser and means for scanning the traffic cone along a set of horizontal lines and then a set of vertical lines, each line being scanned twice before the subsequent line is scanned. For example, each horizontal line is scanned from left to right and then from right to left so that the projectile can receive the laser beam twice during the horizontal scan period for the entire traffic cone. The time interval between the two reception times makes it possible to determine the position of the projectile along a horizontal axis.

Further the projectile receives the laser beam twice during the vertical scanning period of the entire traffic cone. By measuring the time interval between the two reception times is the Position of the projectile determined on a vertical axis. each elementary cell is on the intersection of a vertical scan line centered with a horizontal scan line. The width and the length each cell are chosen so that the diameter of the laser beam completely covers a cell and over the adjacent cells slightly overlaps.

through such a system can reduce the overall power of the laser beam be focused on an elementary cell at a given time. This concentration of the total energy of the laser beam on one single cell gives a significant improvement of the signal-to-noise ratio, so that the power of the laser for a given Range can be reduced.

The invention is based on the object to propose a guidance system which achieves: a further reduction in laser power for a given range; an increase in steering precision; and transmission of messages to the missiles, e.g. B. Information about the evolution of the trajectory of the target.

object The invention is a system which is essentially two optoacoustic Deflector to a laser beam in two orthogonal planes deflecting each other on the symmetry axis of the traffic cone, moreover, the amplitude of the beam can be modulated, to transmit two Cartesian coordinates and one message.

• – Einrichtungen zur Verfolgung eines Zieles und Bestimmung einer Visierlinie;
• – Mittel zum Abtasten eines als Leitkegel bezeichneten Raumteiles mittels eines Laserstrahls, wobei dieser Leitkegel eine Symmetrieachse aufweist, deren Lage der Visierlinie nachgeregelt wird, und wobei der Leitkegel aus elementaren Zellen besteht, die durch den Strahl nacheinander beleuchtet werden;

und ein Projektil mit:

• – Einrichtungen zum Empfangen des Laserstrahls, zum Feststellen, in welcher Zelle sich das Projektil befindet, um daraus eine Korrektur der Flugbahn des Projektils abzuleiten, so daß es sich an die Symmetrieachse des Leitkegels annähert;
• – Mittel zur Bewirkung einer Korrektur der Flugbahn;

dadurch gekennzeichnet, daß die Abtastmittel umfassen:

• – Mittel zum Ablenken des Laserstrahls in zwei zueinander orthogonalen Richtungen;
• – Mittel zum Modulieren der Amplitude des in jede elementare Zelle gesendeten Laserstrahls mit einer für jede Zelle verschiedenen binären Sequenz;

und das die Einrichtungen zum Empfangen des Laserstrahls Mittel umfassen, um diesen Strahl zu demodulieren und die binäre Sequenz zu decodieren.The projectile guidance system of the invention using a directional beam encoded in Cartesian coordinates comprises a launch station comprising:

• - facilities for tracking a target and determining a sighting line;
• - means for scanning a designated as a traffic cone part of space by means of a laser beam, said traffic cone having an axis of symmetry whose position of the line of sight is readjusted, and wherein the traffic cone consists of elementary cells, which are illuminated by the beam successively;

and a projectile with:

• - means for receiving the laser beam, for detecting in which cell the projectile is to derive therefrom a correction of the trajectory of the projectile so that it approaches the axis of symmetry of the cone;
• - means for effecting a correction of the trajectory;

characterized in that the scanning means comprise:

• - means for deflecting the laser beam in two mutually orthogonal directions;
• - means for modulating the amplitude of the laser beam transmitted to each elementary cell with a binary sequence different for each cell;

and the means for receiving the laser beam comprise means for demodulating that beam and decoding the binary sequence.

Further Features and advantages of the invention will become apparent from the following Description and from the drawing, to which reference is made. In the drawing show:

1 schematically a firing station, the projectile, the target and the traffic cone;

2 schematically the section of the traffic cone with a plane which is perpendicular to its axis of symmetry;

3 a timing diagram illustrating the coding of the laser beam for two cells of the traffic cone;

4 a schematic diagram of an embodiment of the system according to the invention; and

5 and 6 Views for explaining the operation of this embodiment.

In 1 creates a firing station 1 a traffic cone 5 for steering a missile 4 against a goal 2 , The traffic cone 5 has an axis of symmetry AS whose position is adjusted so that it coincides with the line of sight LV extending from the firing station 1 to the goal 2 extends. This line of sight is defined by tracking means located in the firing station 1 are located. At a given time the firing station sends 1 a laser beam 3 , which is an elementary cell of the traffic cone 5 illuminated. This elementary cell is cylindrical or of the shape of a cone with a weak opening.

To denote each elementary cell of the traffic cone, the section thereof is viewed with a plane x o which is perpendicular to the axis of symmetry AS and of the missile 4 is traversed at the time considered. The section of the traffic cone with the xoy plane is a surface 7 which is approximately circular; the elementary cell, which at the time considered by the laser beam 3 is illuminated, has a section with the plane xoy, which at least theoretically a square surface 6 is. The location of the surface 6 is given with respect to the axes ox and oy which are orthonormal and intersect each other at the point o which lies on the axis of symmetry AS. The axis ox is horizontal, while the axis oy is contained in a vertical plane. The one cell whose cut is the surface 6 is called xy in this sysstem xoy via the Cartesian coordinates.

In practice, the plane xoy and its frame move by moving the missile 4 accompany. In order for the given cell to maintain the same coordinate values xy, a variable unit must be used as the distance unit, with respect to the axis of symmetry AS, whose change in the distance of the missile 4 from the firing station 1 equivalent. For example, this unit will be 1/16 the radius of the cut surface 7 of the traffic cone 5 set with the level oxy.

The 2 shows the cut surface 7 and illustrates the operation of the system by showing the location of the elementary cells, one after another in the traffic cone 5 be illuminated. These cells are represented by their intersections with the xoy plane. The sampling takes place successively over 16 columns, z. In order of y-coordinate values successively increasing from y = -8 to +8 in equal increments of one unit each; the same applies to the increase in the x-coordinate values, which likewise increase in each case in one unit.

The Cells theoretically have a square cut surface. The lighting, however, is circular with a Gaussian distribution. The cells therefore have no clean Borders, but partially overlap each other. Because the Cells evenly in the directions ox and oy distributed, they cover each other in the same way, regardless of their location. The emitted in the traffic cone Energy is thus uniformly distributed, and the steering precision is uniform throughout the entire traffic cone.

A remarkable feature of the scanning of the cone in that each column virtually coincides with the one in is scanned for o symmetrically located column. These Special feature arises from the coding method used by means of which each cell of the traffic cone is identified by the Laser beam is modulated. This coding method consists essentially therein, a binary sequence different for each cell to transfer and a complementary binary Sequence for the cell to transmit symmetric with respect to the axis of symmetry AS.

Of the Laser beam is modulated to be in the form of a binary sequence to transmit two coordinates x, y indicating the position indicate a cell in the traffic cone.

at In a concrete embodiment, the laser operates continuously. Each bit of the binary sequence is transmitted by modulating the amplitude of the laser beam.

It can use various conventional modulation techniques Find application. A modulation that consists in that for the value 1 of the binary sequence is a lighting and the Value 0 no illumination takes place, would have the disadvantage that no the average disappearing component would be guaranteed. A better modulation method is, for example, that each bit of the sequence by two elementary information is shown, whose duration is equal to half a bit period. For example every bit of value 1 is in the form of a lighting during half a bit period, followed by a miss illumination during a half bit period; the bits from Value 0 is transmitted in the opposite way. Moreover, this modulation method becomes error detection allows, because each transmitted bit contains a transition. A missing bit can therefore be counted the transitions are detected.

The application of such a 100% modulation technique, better referred to as a digital modulation technique, is to direct the laser beam to a given cell 9 divert to transmit elemental information; Further, the laser beam becomes a cell 9 ' deflected, which is symmetrical to the given cell with respect to the point o, to transmit opposite elementary information. The to the given cell 9 transmitted binary information is thus complementary to the bit sequence, during the same time interval to the symmetric cell 9 ' is transmitted.

These special form of digital modulation of the laser beam draws characterized by a special efficiency, because the laser beam is sent without interruption. To this efficiency comes the effect adding a concentration of the laser beam on a single cell, so that a significant reduction in mean laser power is possible compared to a laser power for a system with spatial coding.

It remains a partial overlap of the cells, resulting in a significant advantage over the method of spatial Coding according to the prior art results. The facilities for receiving of the laser beam, which is inside the missile namely, can almost simultaneously Coordinates of multiple cells are received and interpolated coordinates calculate, taking into account each received Amplitudes for each of the received binary sequences. This interpolation enables a refined determination the position of the missile to the steering precision to increase.

The 3 illustrates the coding method used to encode the coordinates of the cell 9 and 9 ' by means of a binary sequence S and the complementary sequence application finds. This sequence S begins with two bits to distinguish between top and bottom to a cell belonging to the upper half space, z. For example, the cell 9 to distinguish from a symmetrically located cell belonging to the lower half-space, like the cell 9 ' , These two bits for distinguishing between top and bottom are formed by a so-called reference bit and a so-called sign bit which is the sign of the y-coordinate of the considered cell. The sequence S then contains three bits, by which the absolute value of y is coded. The sequence S then contains four bits representing the sign and the absolute value of x.

The Decoding the modulation of the received by the missile Laser beam takes place by means of an aboard the missile arranged decoders. This decoder starts with a binary sequence T, wherein one bit is 1 when the Decoder detects a lighting for a duration, which is equal to half a bit period, followed by a lack of illumination during a half bit period. One bit of the sequence T has the value 0 if the decoder has a lack of illumination during a half period and then a lighting during an equally half period.

Subsequently the sequence T is decoded to be between the top and the bottom To distinguish half-space and to reproduce the values x, y. If the missile is in the upper half-space begins the reception of the directional beam with illumination during a duration equal to half a bit period. When the missile is in the lower half space, the reception of the beam begins with illumination for half a bit period, followed by a lack of lighting while also a half bit period. The values 01 or 10 of the first two Bits of the sequence T thus distinguish between the upper and lower Half space. Then the values x and y have to be decoded become.

For example, if the missile is inside the cell 9 demodulation of the laser beam received by the missile results in the following binary sequence:
T (9): 0 1 1 0 1 1 0 1 0

The both first bits, 01, indicate that the missile is located in the upper half-space. The second, third, fourth and fifth bits result directly in the coded one Value y = 1 010 = +5. The sixth, seventh, eighth and ninth bits result directly the value x = 1 010 = +2.

When the missile is inside the cell 9 ' demodulation of the laser beam received by the missile results in the following binary sequence:
T (9 '): 1 0 0 1 0 0 1 0 1

The first two bits 10 indicate that the missile is in the lower half-space. The second bit returns the sign of y for the cell 9 ' , The third, fourth and fifth bits give the absolute value of the quantity y complemented to 1. By complementing, the absolute value of y can be found again:
| Y | = 1 0 1 and y = -5.

The sixth bit gives the sign of x for the cell 9 ' , The seventh, eighth and ninth bits give the absolute value of the quantity x complemented to 1. By complementing, the absolute value of x can be found:
| X | = 0 1 0 and x = -2.

The Sequence S may further include an additional binary word that makes a message. In this message can it is information about the evolution of trajectory act of the target, so that the on-board computer of the missile can make a better correction of his trajectory. In this message it can also be information about a possible Instruction error of the symmetry axis of the traffic cone act, so the on-board computer can calculate such a trajectory correction that the missile approximates to an axis opposite the symmetry axis of the traffic cone is offset. After all the message may also be an activation of an approach rocket, which is carried by the missile.

If the missile is in the upper half-space results the binary sequence obtained by demodulation of the laser beam is received, directly the message bits. When the missile is in is located in the lower half space, the decoder complements the through Demodulation of the laser beam obtained binary sequence, to reflect the exact value of the message bits.

If the message is long, it can be in multiple binary words be divided, each with an identification prefix are provided and transmitted over several consecutive sampling periods become.

to Acceleration of the transmission rhythm for the Traffic cones can be scanned with transmission alternate the coordinates with scans alone, in which only a message is transmitted, so that the Messaging is only assigned time if a message must actually be transmitted. The messages are then from the coordinates by an additional Differentiated bit.

An alternative embodiment of the coding method is that a pulse laser is used whose rhythm is greater than that of the bits, instead of a continuously operating laser. Furthermore, a receiving device is used which is designed for the laser pulses. These laser pulses then form a subcarrier that is digital through the binary Sequence is modulated, analogous to that described for a CW laser. This results in an improvement of the signal-to-noise ratio for a given average laser power. Furthermore, less sensitivity to flame and smoke disturbances is achieved by propulsion of a missile.

Another variant is to use a CW laser and chop the laser beam at a frequency much greater than the bit frequency of the sequence to be transmitted. The encoder 31 must then have logic means to provide a logic signal which is the product of the sequence to be transmitted with a chopping signal. This product signal replaces the previous binary sequence to control the jumps of the laser beam.

Another variant is to use a pulse laser whose frequency is twice the bit frequency, with means provided to synchronize it with the bit frequency. The modulation of the laser beam is to send out two pulses for each bit, regardless of its value. To send a bit from value 1 to the cell 9 For example, the first pulse becomes the cell 9 deflected while the second pulse to the symmetrically located cell 9 ' is distracted. Conversely, the transmission of a bit from the value 0 to the cell 9 the first impulse to the cell 9 ' and the second pulse to the cell 9 distracted.

The 4 shows a schematic diagram of an embodiment of the system according to the invention. This embodiment comprises means for scanning the cone of traffic: a laser 33 , two deflecting mirrors 34 . 35 , an afocal optical adapter 36 , two acousto-optic deflectors 37 . 37 ' , an afocal zoom 38 and control means 39 , It further comprises tracking means: a scanning device 40 , an optical device 41 , a cooled detector line 42 , a tracking calculator 43 , a directive device 44 and a dichroic plate 45 , Furthermore, devices for automatic harmonization of the sight lines are provided, which consist of a shutter 46 , a damping plate 47 , a cube corner 48 and a device 49 to control the harmonization of the sighting lines.

It should be noted that the tracking means and the means for scanning the traffic cone comprise a common optical path provided by the pointing device 44 is formed.

The laser 33 is a CO ₂ laser that operates continuously at the 10.6 μm wavelength with linear polarization. The deflection mirror 34 . 35 have as the sole task to reduce the space requirements of the entire device. They direct the laser beam 33 at the entrance of the device 36 which brings the diameter and the divergence of the laser beam to values that are suitable for the subsequent optical elements. The acousto-optic deflectors 37 and 37 ' deflect the beam within a vertical plane or horizontal plane. Each consists of a Bragg cell of conventional design, which makes it possible to direct a laser beam quickly.

Each of them contains a germanium crystal traversed by mechanical waves generated by a piezoelectric transducer excited by a high frequency generator. The design of this generator is conventional. The distractor 37 has an input for receiving a setpoint voltage, which is a first output of the control means 39 provides and determines a deflection angle φx. This angle corresponds to a coordinate x over an approximately linear relationship, because the deflection angles remain smaller than 10 °. The distractor 37 ' has an input for receiving a setpoint voltage, which is a second output of the control means 39 and determines a deflection angle φy corresponding to a coordinate y. The distractor 37 ' leaving beam then traverses the afocal zoom 38 which makes it possible to adapt the divergence of the laser beam and the intensity of its deflection to the distance between the firing station and the missile. The use of this zoom 38 will be described below. The zoom 38 includes a conventional control, which is controlled by a setpoint voltage, which a third output of the control means 39 supplies. This voltage represents a magnification G which depends on the distance traveled by the missile since its launch.

The dichroic plate 45 is transmissive for wavelengths greater than 10 μm and reflects wavelengths of less than 10 μm. The one out of the zoom 38 exiting laser beam traverses the dichroic plate 45 with low attenuation based on the reflection of a small fraction of its energy. Subsequently, the beam through a directive device 44 which is a conventional opto-mechanical device provided by the tracking arithmetic circuit 43 is controlled in such a way that the sight line of the device 44 permanently directed against the target or a future position, that of the device 43 is predicted. An output of the device 44 thus gives a laser beam 3 whose middle direction is the line of sight, which is the computing device 43 determined, and moves about this central direction to scan the traffic cone, with deflecting movements by the deflector 37 and 37 ' be abandoned.

The tracking is done by detecting the infrared radiation emanating from the target. This radiation is over a bundle 50 receive the device 44 traversed and almost completely through the dichroic plate 45 to the optical device 41 is reflected, which is an image on the detector 42 generated. The scanning device 40 is between the detector line 42 and the device 41 pasted to scroll through the image. It may, for example, perform a circular scan and is of conventional design. The detector line 42 consists of a series of infrared sensitive cells. It is felt by cryogenic agents. It has an output connected to an input of the tracking calculator 43 connected is. The circular scanning device passing through the device 40 is realized causes a passing of the image on the detector line 42 , The output of this detector line 42 thus provides a video signal representing a radially scanned image. The device 43 determines a sighting line from the target position and its development in the image sequence. The one in the device 43 applied algorithm is conventional.

The devices 40 and 44 are opto-mechanical devices that have a wide optical passband to obtain a target image in a large spectral range.

In each guidance system, harmonization is required between the sighting line of the tracking means and the line of sight of the scanning means for scanning the traffic cone. These lines are not completely colinear, because the plate 45 is not exactly below 45 ° to the optical axis of the zoom 38 and the directive device 44 and with respect to the optical axis of the optical device 41 inclined; another reason is that the optical axes of all other optical elements are not completely stable when vibrations or temperature changes occur.

Before each start controls the device 49 an automatic harmonization of the sighting lines. For this purpose it controls the opening of a closure 46 that between the plate 45 and the cube corner 48 in the extension of the optical axis of the optical device 41 is inserted. This closure 46 then passes a fraction of the laser beam through the plate 45 is reflected. This fraction of the laser beam is through the cube corner 48 reflected back to itself, regardless of the orientation of the cube corner 48 , He then passes through the lock 46 again, to the plate 45 and the optical device 41 to cross. Finally he arrives at a cell of the detector 42 , When the position of the plate 45 imperfect, the fraction of the laser beam falling on the detector drops 42 arrives, not at a point that represents the center of the image. The device controls to measure the harmonization error in two orthogonal directions 49 the distractor 37 in such a way that a deflection of a predetermined size takes place in the vertical plane, which causes a pivoting of the laser beam on the detector 42 incident. An output of this detector 42 is with an input of the control device 49 connected to it to supply the video signal resulting from the scanning of the laser beam on the detector 42 results. The control device 49 determines two correction signals to a first correction input to the deflector 37 or a first correction input for the deflector 37 ' invests. These correction signals are algebraically added to the setpoints provided by the control means. When the device 49 has completed this measurement, closes the shutter 46 in that said fractional part of the laser beam is receiving an image on the detector 42 can not disturb.

Although the fraction of the laser beam coming from the plate 45 is reflected very small compared to the other fraction of the laser beam that is this plate 45 has to pass through a damping plate 47 be provided on the path of the fraction that passes through the cube corner 48 is reflected, so that the detector 42 is not controlled in saturation.

The measurement of the harmonization error takes place for several magnification values of the zoom 38 , The various values of the corresponding correction signals are in the device 49 stored and in real time the devices 37 . 37 ' while the value of the magnification increases during the flight of the missile.

The control means 39 include: a flow control 30 , an encoder 31 and a device 32 to calculate the magnification. The flow control 30 has three outputs: a first and a second output which assign the coordinates x and y to the two inputs of the encoder 31 output, and a third output, which is a start signal for the missile to an input of the device 32 to calculate the magnification. This device 32 determines the distance traveled by the missile from its launch and deduces the value for the magnification G from it. An output of the device 32 makes the third exit of the means 39 ,

The encoder 31 is further provided with an input which is connected to an output of the device 43 is connected to the tracking computation, which supplies him with a binary word, which one for Missile represents to be transmitted message. The encoder 31 generates a binary sequence consisting of the value y, the value x and the message word. From the values x and y, the encoder determines 31 two values for the angular deflection φx, φy corresponding to the position of a cell to be illuminated at the time in question, corresponding also to the cell which is symmetrical with respect to the symmetry axis of the guide cone. To illuminate these two cells by modulating the laser beam with the binary sequence, the encoder provides 31 to the distractor 37 a setpoint signal whose value represents + φx or -φx. He also delivers to the distractor 37 ' a setpoint signal whose value represents + φy or -φy.

The distracters 37 . 37 ' are provided with second correction inputs, each with one of two outputs of the tracking calculator 43 are connected. These inputs receive at all times correction signals φxo and φyo that are algebraic to the desired value signals φx and φy within the deflectors, respectively 37 and 37 ' be added. By means of these correction signals, the direction of the direction of the axis AS of the traffic cone on the by the device 43 calculated line of sight LV, if the latter determines a directive error based on the inertia of the directive device 44 due to sudden changes in the path of the target. The speed of the distractor 37 and 37 ' So it makes it possible to compensate for errors in the directive, which is based on the inertia of the directive device 44 based.

The 5 and 6 illustrate the operation of this embodiment of the control system according to the invention. The 5 shows the evolution of the traffic cone in the course of the flight of the missile 4 , At the time considered, the missile becomes 4 through a traffic cone 5 steered, a cut surface 55 having a plane which is perpendicular to the axis of symmetry AS of the traffic cone. This area 55 is approximately circular and has a diameter that varies as a function of that of the missile 4 changed distance changes. The evolution of the diameter of this area 55 is shown in dashed lines.

When the missile 4 from a ramp 58 is started, the beam is through the control system 57 sent, which is close to the ramp 58 located. The sight line LV of the control system 57 coincides with the symmetry axis AS of the traffic cone. The launcher of the ramp 58 is parallel to this sighting line, but does not match it. At the beginning of his flight, the missile is therefore outside the traffic cone. In order to prevent the missile from leaving the traffic cone and being lost, the opening angle of the traffic cone is increased during a so-called tracking phase, which continues until the missile has reached a distance d1.

During the tracking phase, the traffic cone has 51 a solid, relatively large opening, which is achieved by the strength of the deflection of the acousto-optic deflectors 37 . 37 ' is enlarged. For this purpose, the encoder provides 31 to the distracters 37 . 37 ' Setpoints φx, φy greater than those corresponding to the pull phase following the tracking phase. During this tracking phase, the zoom is received 38 a magnification value G which is the minimum value. For example, the number of elementary cells constituting the traffic cone is increased by a factor of 4, and the deflection period is increased by the same amount.

The deflection period can not be increased infinitely. If the number of cells is insufficient to make a traffic cone 51 One solution is to cover these cells only at the circumference of the cone 51 to distribute. It then enters an inactive cone 56 on, in which there is no elementary cell and thus no steering takes place. The missile 4 penetrates the traffic cone 51 by necessarily traversing its circumference so that the absence of cells in the vicinity of the axis of the traffic cone is of no importance.

The 6 shows the section of the Leitzellen with a plane which is perpendicular to the axis of symmetry AS, at a time of tracking phase. The inactive cone 56 is shown hatched.

The follow-up phase is followed by three more leadership phases. While the missile is at a distance between d1 and a distance d2, the diameter of the cut surface of the pilot cone is kept constant by the amount of deflection through the acousto-optic deflectors 37 . 37 ' is kept constant, depending on the distance traveled by the missile. The surface 55 then shifts to form a cylinder 52 , As the missile moves away, the size of the cut surface of each elementary cell increases. Since the number of elemental cells is constant and the diameter of the cone also, the cells gradually take an increasing share of the surface 55 one.

When the missile is at a distance between a distance d2 and a distance d3, the diameter of the cut surface becomes 55 held constant by the setpoint for the magnification D is kept constant, which the zoom 38 is supplied. The surface 55 therefore shifts with the missile within a cylinder 53 ,

If the missile has exceeded the distance d3, the zoom has 38 reaches its maximum magnification, and it is no longer possible the diameter of the surface 55 to keep constant. This therefore shifts and is magnified linearly as a function of the distance covered, with a cone 54 is generated, which has a small opening.

The device 32 to calculate the magnification receives a start signal from the sequencer 30 , From this time on, it determines the magnification values G as a function of a predetermined time law. The flow control 30 determines a sequence of values x and a sequence of values y which always produce a periodic scan, but which develop in dependence on the time since the start of the missile according to a predetermined law of time. The determination of these two laws from the optical laws and from the characteristics of the zoom 38 and the distractor 37 . 37 ' lies within the scope of expert knowledge. The encoder 31 and the computing device 32 can be formed by a microprocessor. His programming is within the skill of the art.

Under the numerous embodiments of the invention to emphasize that uses a dichroic plate which reflects at the wavelength of the laser and lets through the wavelengths, which intended to generate an image of the target. In this case is the optical path of the means for scanning the cone with the optical path permuted by the shutter, the damping plate and cube corner are made is.

It can also be used a laser whose wavelength deviates from 10.6 microns. Furthermore, a second-dimensional image detector may be used, in which case the scanning device 40 eliminated. An infrared camera can also be used.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited non-patent literature

• - Optical Command and Beamrider Missile Guidance, RL Sitton, SPIE. Vol. 317, pp. 358-364 [0005]
• "Michael Higgins, Gerald Titus, John Evans, Richard Martyn, British Aerospace UK" - "An improved acousto-optic laser scanner guidance system" [0007]

Claims (10)

Guiding system for projectiles using a directional beam coded in Cartesian coordinates with a launching station comprising: - means ( 40 to 45 ) to pursue a goal ( 2 ) and determination of a sighting line (LV); - Medium ( 30 to 39 . 44 ) for scanning a designated as a traffic cone space part ( 5 ) with the laser ( 33 ) emitted beam ( 3 ), wherein the traffic cone has an axis of symmetry (AS), the position of the sighting line (LV) is readjusted, and wherein this traffic cone ( 5 ) from elemental cells ( 9 ) passing through the beam one after the other ( 3 ) are illuminated; and a projectile ( 4 ), comprising: - means for receiving the laser beam ( 3 ) and determining in which cell the projectile is located, in order to derive therefrom a correction of the trajectory of the projectile, by means of which it is directed to the symmetry axis (AS) of the guide cone (FIG. 5 ) approximates; - means for effecting this correction of trajectory; characterized in that the scanning means ( 30 to 39 . 44 ): - means ( 37 . 37 ' ) for deflecting the laser beam in two mutually orthogonal directions; - Medium ( 30 . 31 . 37 . 37 ' ) for modulating the amplitude of the laser beam ( 3 ), which is sent into each elementary cell, with a binary sequence different for each cell; and in that the means for receiving the laser beam ( 3 ) Have means to demodulate that beam and to decode the binary sequence. System according to claim 1, characterized in that the means for modulating the laser beam ( 3 ) an encoder ( 31 ) to provide binary sequences arranged such that each sequence corresponding to a cell comprises a first and a second binary word each representing one of two Cartesian coordinates (x, y) representing the position of the considered cell in a Cartesian reference system whose origin (o) on the symmetry axis (AS) of the traffic cone ( 5 ) lies. System according to claim 1, characterized in that the means for modulating the amplitude of the laser beam ( 3 ), which is a given cell ( 9 ), means ( 30 . 31 . 37 . 37 ' ) to the beam ( 9 ) for each elementary information with a predetermined value to a cell ( 9 ' ), which are symmetrical to the given cell ( 9 ) with respect to the axis of symmetry (AS) and around the beam for each elementary information of opposite value to the given cell (FIG. 9 ) distract. System according to claim 2, characterized in that the modulation means comprise an encoder ( 31 ) to further encode a message to be transmitted in the binary sequence, and in that the means for receiving the laser beam ( 3 ) comprise a decoder to decode this message. System according to claim 1, characterized in that the means ( 40 to 45 ) for the pursuit of the objective and the means ( 30 to 39 . 44 ) for scanning the traffic cone ( 5 ) have a common optical path, which by a directional device ( 44 ) which orients the sighting line of the tracking means and the sighting line of the scanning means; wherein the directive device ( 44 ) of the laser beam ( 3 ) in one and in the opposite sense by a light beam ( 50 ) trapped in the sight line (LV). A system according to claim 5, wherein the means for target tracking comprises an optical detector ( 42 ), characterized in that in order to harmonize the line of sight of the target tracking means ( 40 to 45 ) and the sighting line of the funds ( 30 to 39 . 44 ) are provided for scanning the guide cone: a semipermeable plate ( 45 ) and a catadioptric device ( 48 ), which are arranged in such a way that a fraction of the laser beam ( 33 ) (At a predetermined point of the detector 42 ) is projected when the sighting lines are harmonized. System according to claim 1, characterized in that the laser ( 33 ) is a CW laser and that the modulation means further comprises 31 ) to the laser beam ( 33 ) with a frequency much higher than the frequency of the bits of the binary sequence to be transmitted. System according to claim 1, characterized in that the laser ( 33 ) is a pulse laser whose frequency is greater than that of the bits of the binary sequence to be transmitted. System according to claim 1, characterized in that the laser ( 33 ) is a pulse laser whose frequency is twice the frequency of the bits in the binary sequence to be transmitted, and in that the modulation means further comprises means for synchronizing the laser to the frequency of the bits in the sequence. System according to claim 1, characterized in that the scanning means ( 30 to 39 . 44 ) Medium ( 30 to 32 ) to the opening ( 51 ) of the traffic cone ( 5 ) depending on the missile ( 4 ), this opening being larger during a tracking phase during which the projectile ( 4 ) in the traffic cone ( 5 ), and means for distributing these elemental cells ( 6 ) over the circumference of the traffic cone ( 5 ) during the tracking phase, wherein a central zone ( 6 ) remains without cells.