EP0833122B1 - Homing seeker head of a flying body - Google Patents

Abstract

The seeker system has a Charge Coupled Device (D1) array forming a matrix detector of reflected light. Laser light is directed towards a target and reflected back towards the seeker. The matrix detector is attached to an identifiaction system (SI1) to detect target signals. The seeker is mounted on the front of a moving body, and the field of view covers the detection zone. Light rays are focussed (6) onto the matrix detector.

Description

The present invention relates to a seeker mounted on a flying body, and intended to determine orders to guide said body flying towards a target.

• un système de détection de cible ;
• une source d'informations inertielles ; et
• une unité centrale de traitements d'informations déterminant lesdits ordres de guidage.

The present invention applies more specifically to a seeker of the type comprising in particular:

• a target detection system;
• a source of inertial information; and
• a central information processing unit determining said guidance orders.

We know that, to guide a flying body, for example from an airplane, helicopter or land post, to a target, by means of such a seeker, it is usual to point a laser illuminator, for example a laser rifle, which emits flashes of light corresponding to pulses short, time-coded and frequency-illuminated lights determined (s), on said target so as to illuminate it. The seeker detects the flashes of light that are reflected by the target and it determines their direction of reflection which corresponds to the direction of the target, which then allows to calculate the guidance orders of said body wheel.

In known manner, to carry out detection and localization of a target thus illuminated, the seeker uses a reduced field sensor, which is mounted on a platform of orientation and stabilization of the line of sight of said sensor.

• sa mise en oeuvre est complexe ;
• il est nécessaire de déterminer, de façon extrêmement précise, la position de ladite plate-forme par rapport à un référentiel de référence du corps volant ; et
• sa réalisation est très coûteuse.

Such a conventional solution has many drawbacks, in particular:

• its implementation is complex;
• it is necessary to determine, in an extremely precise manner, the position of said platform with respect to a reference frame of reference of the flying body; and
• its realization is very expensive.

The object of the present invention is to remedy these drawbacks. It concerns a cost-effective seeker, allowing to guide, in a simple and precise way, a body flying towards a target.

• un système d'identification d'éclats lumineux provenant de la cible ; et
• un système de localisation de la cible, qui comporte :
  • un détecteur photosensible monté à poste fixe sur le corps volant et comprenant une matrice de capteurs photosensibles ; et
  • un moyen de focalisation qui projette sur ladite matrice du détecteur photosensible l'image de la scène située à l'avant du corps volant.

To this end, the seeker of the type recalled above is remarkable, according to the invention, in that said target detection system comprises:

• a system for identifying flashes of light from the target; and
• a target location system, which includes:
  • a photosensitive detector mounted on a fixed post on the steering wheel and comprising a matrix of photosensitive sensors; and
  • focusing means which projects onto said matrix of the photosensitive detector the image of the scene located at the front of the flying body.

So, thanks to the use of a photosensitive detector which includes a matrix of specified photosensitive sensors below, and which thus presents a large field susceptible cover the entire target detection area and optically discriminate different parts of said area detection, said photosensitive detector can be mounted at fixed position on the flying body, which avoids having to set up an orientation and stabilization platform and therefore overcomes the aforementioned drawbacks.

• d'une part, renforce les signaux électriques présentant un temps de montée rapide et correspondant à un éclat lumineux reçu par la diode photosensible ; et
• d'autre part, atténue les signaux électriques présentant une variation temporelle lente et correspondant à des illuminations faiblement variables en intensité, de ladite diode photosensible.

In addition, said photosensitive detector comprises photosensitive sensors provided respectively with photosensitive diodes capable of transforming the light energy received into an electrical signal, and each of said photosensitive sensors comprises, in addition to said photosensitive diode, means for processing the generated electrical signals by said photosensitive diode, said processing means comprising a shunt electrical circuit which:

• on the one hand, reinforces the electrical signals having a rapid rise time and corresponding to a light burst received by the photosensitive diode; and
• on the other hand, attenuates the electrical signals having a slow temporal variation and corresponding to illuminations slightly variable in intensity, of said photosensitive diode.

Furthermore, advantageously, said identification system of flashes of light includes a photosensitive diode likely to detect light flashes from said scene located at the front of the flying body and means likely to determine, among said luminous flashes detected, those from the designated target, which allows to obtain a simple, precise and little identification system expensive.

Finally, advantageously, said detection system target has a shutter that closes the field of vision of the target location system, said shutter being controlled so as to release said field of vision each time once a light burst from said target is expected, which avoids putting said locating system target in continuous service and helps protect it against damaging light beams when it is not not in use.

• chacun desdits capteurs photosensibles comporte un moyen de binarisation permettant de déterminer un état binaire dudit capteur photosensible, en fonction du signal formé par ledit moyen de traitement de signaux électriques ; et
• chacun desdits capteurs photosensibles comporte un moyen de mémorisation permettant d'enregistrer ledit état binaire.

In addition, advantageously:

• each of said photosensitive sensors comprises a binarization means making it possible to determine a binary state of said photosensitive sensor, as a function of the signal formed by said means for processing electrical signals; and
• each of said photosensitive sensors comprises a storage means making it possible to record said binary state.

Furthermore, advantageously, said identification system of light flashes is likely to detect a characteristic variation in illumination, which is greater to a predefined variation, of at least one of said sensors photosensitive.

In a first variant, said identification system of flashes of light monitors the electric current consumed by each of said photosensitive sensors, any increase of said electric current consumed, which is greater than a predefined increase, indicating a variation in illumination feature.

In a second variant, said identification system of light flashes monitors the binary state of said sensors photosensitive, any change from binary state to a state representing the detection of a luminous flash indicating a characteristic lighting variation.

Preferably, in this second variant, said system identification of flashes of light includes a first shift register network capable of transmitting the binary state of all the photosensitive sensors of the photosensitive detector.

Furthermore, in said second embodiment, said location system advantageously makes it possible to locate on the photosensitive detector array the position of each photosensitive sensor which detects a light burst.

Advantageously, said location system comprises a second network of shift registers, allowing transmit the binary state in serial according to a predefined order of all photosensitive sensors, the order of each photosensitive sensor in the transmission series being representative of its position on the matrix.

In addition, to specify the location in the event that flashes of light are detected by several photosensitive sensors, said location system advantageously comprises a calculation means making it possible to determine a central position from the localized positions of all the photosensitive sensors having detected a light burst.

• détermine l'intensité du signal engendré par le moyen de traitement de chacun des capteurs photosensibles ayant détecté un éclat lumineux ;
• détermine la position de chacun desdits capteurs photosensibles ayant détecté un éclat lumineux ; et
• calcule, à partir des intensités et des positions ainsi déterminées, le barycentre correspondant qui représente la localisation recherchée.

In addition, in an advantageous implementation, said localization system:

• determines the intensity of the signal generated by the processing means of each of the photosensitive sensors having detected a light burst;
• determines the position of each of said photosensitive sensors having detected a light burst; and
• calculates, from the intensities and positions thus determined, the corresponding barycenter which represents the desired location.

La figure 1 illustre schématiquement un autodirecteur conforme à l'invention et monté sur un corps volant.

La figure 2 montre un premier mode de réalisation d'un système de détection d'un autodirecteur conforme à l'invention.

La figure 3 montre un second mode de réalisation d'un système de détection d'un autodirecteur conforme à l'invention.

La figure 4 montre schématiquement un détecteur photosensible dudit second mode de réalisation.

La figure 5 illustre, en fonction du temps, les opérations réalisées conformément à l'invention, par un système de détection d'un autodirecteur.

La figure 6 montre schématiquement un capteur photosensible du détecteur photosensible de la figure 4.

La figure 7 illustre le traitement d'un signal électrique par un moyen de traitement du capteur photosensible de la figure 6.

The figures of the appended drawing will make it clear how the invention can be implemented. In these figures, identical references designate similar elements.

Figure 1 schematically illustrates a seeker according to the invention and mounted on a flying body.

FIG. 2 shows a first embodiment of a detection system of a seeker according to the invention.

FIG. 3 shows a second embodiment of a detection system of a seeker according to the invention.

FIG. 4 schematically shows a photosensitive detector of said second embodiment.

FIG. 5 illustrates, as a function of time, the operations carried out in accordance with the invention, by a detection system of a seeker.

FIG. 6 schematically shows a photosensitive sensor of the photosensitive detector of FIG. 4.

FIG. 7 illustrates the processing of an electrical signal by a processing means of the photosensitive sensor of FIG. 6.

The seeker 1 according to the invention is mounted on a flying body M, for example a missile, of which only schematically represented the front part in FIG. 1.

• un système de détection de cible SD1 ou SD2 ;
• une source d'informations inertielles 2 ; et
• une unité centrale 3 de traitement d'informations qui est reliée audit système SD1 ou SD2 et à ladite source 2, respectivement par l'intermédiaire de liaisons 4 et 5, et qui détermine lesdits ordres de guidage.

In known manner, said seeker 1, which is intended to determine orders for guiding said flying body M towards a target C, comprises in particular:

• a target detection system SD1 or SD2;
• a source of inertial information 2; and
• a central information processing unit 3 which is connected to said system SD1 or SD2 and to said source 2, respectively via links 4 and 5, and which determines said guidance orders.

In known manner, said target C is illuminated by means of a illuminator not shown, by EL light flashes corresponding to short, coded pulses, emitted generally at constant and predefined time intervals, as assumed in this example.

To be able to guide the flying body M, the SD1 or SD2 target detection system identifies among all the light beams received said EL light flashes from target C, i.e. reflected by this last after its illumination, and it determines the direction.

Of course, in the context of the present invention, in a particular mode of use and embodiment not represented, said target can also emit itself said light flashes to indicate to the flying body the direction to follow to reach it.

• un système d'identification SI1 ou SI2 d'éclats lumineux EL provenant de la cible C et émis à intervalles de temps constants et prédéfinis ; et
• un système de localisation de cible SL1 ou SL2 qui comporte :
  • un détecteur photosensible D1 ou D2 monté à poste fixe sur le corps volant M et comprenant une matrice de capteurs photosensibles ; et
  • un moyen de focalisation 6 ou 7, qui projette sur ledit détecteur photosensible D1 ou D2 l'image de la scène située à l'avant du corps volant M et centrée par rapport à un axe de visée AV de l'autodirecteur 1.

According to the invention, to locate the target C, said detection system SD1 or SD2 comprises:

• an identification system SI1 or SI2 of EL light flashes coming from the target C and emitted at constant and predefined time intervals; and
• a target location system SL1 or SL2 which comprises:
  • a photosensitive detector D1 or D2 mounted at a fixed position on the flying body M and comprising a matrix of photosensitive sensors; and
  • a focusing means 6 or 7, which projects onto said photosensitive detector D1 or D2 the image of the scene located at the front of the flying body M and centered relative to a line of sight AV of the seeker 1.

The elements SI1, SL1, D1 and 6 above correspond to the essential elements of a first embodiment SD1 of the detection system, shown in Figure 2, while the elements SI2, SL2, D2 and 7 correspond to those of a second embodiment SD2 shown in FIG. 3.

Thus, as thanks to the invention, the photosensitive detector D1 or D2 is fixed, seefinder A does not require stabilization platform (which is complex and expensive), as is the case for known seekers.

• le détecteur photosensible D1 est un détecteur matriciel, du type à dispositif à transfert de charge, qui est relié par une liaison 8 à une unité de calcul 9 qui localise la cible C à partir des informations reçues dudit détecteur photosensible D1 ; et
• le système d'identification SI1 d'éclats lumineux EL comporte une diode photosensible 10, qui transforme l'énergie lumineuse reçue en un signal électrique, et un moyen de focalisation 11 qui adresse à ladite diode photosensible 10 les éclats lumineux EL provenant de la scène vue par le détecteur D1 et centrée par rapport à l'axe de visée AV de l'autodirecteur 1.

In the first embodiment SD1 of FIG. 2:

• the photosensitive detector D1 is a matrix detector, of the charge transfer device type, which is connected by a link 8 to a calculation unit 9 which locates the target C from information received from said photosensitive detector D1; and
• the identification system SI1 of light flashes EL comprises a photosensitive diode 10, which transforms the light energy received into an electrical signal, and a focusing means 11 which addresses to said photosensitive diode 10 the light flashes EL coming from the scene seen by the detector D1 and centered with respect to the line of sight AV of the seeker 1.

Said SI1 system transmits the electrical signals generated by the photosensitive diode 10 to the calculation unit 9 by a link 12.

From these signals, said calculation unit 9 is likely to identify said target C, in the manner described below with reference to the second embodiment in Figure 3.

The detection system SD1 also includes a shutter 13 which is mounted at the front of the SL1 system on the line of sight AV so as to block the detector's field of vision photosensitive D1.

Preferably, said shutter 13 closes, in operation normal, said field of vision and it only releases it when the computing unit 9 announces to him, via a link 14, that a target C has been identified by the system SI1.

More specifically, said field of vision is released when EL light burst from target C is expected to so the photosensitive detector D1 can then detect this EL light burst and the SD1 system can deduce the location of target C.

In the second embodiment shown in the figure 3, the detection system SD2 is a unique system, in which the SI2 identification system and the location SL2 both include said detector photosensitive D2, as specified below with reference to Figure 4.

Said SD2 detection system comprises, in addition to said photosensitive detector D2 and said focusing means 7, a central unit 15 which is connected by a link 16 to the photosensitive detector D2, which controls the elements essentials of said photosensitive detector D2, represented on Figure 4 and specified below, which includes the case appropriate some of these elements and who receives and processes the results generated by them.

As can be seen in Figure 4, the photosensitive detector D2 includes photosensitive sensors H arranged as a matrix.

Said photosensitive sensors H are interconnected in rows L1, L2, L3, L4, L5 and in columns C1, C2, C3, C4.

According to the invention, said identification system SI2 detects any variation in the illumination of one of said sensors photosensitive H, which is greater than a predefined value and which is characteristic of the illumination of said sensor photosensitive H by an EL luminous brightness.

In the embodiment shown in FIG. 4, said identification system SI2 monitors the binary state specified below of all said photosensitive sensors H also specified below, so any changes state, state 0 (or state not illuminated by a flash luminous EL) towards state 1 (or state illuminated by a burst EL), is considered as a variation of illumination characteristic, i.e. is representative of the EL light flash detection.

• un réseau 18 de registres à décalage, reliés respectivement aux lignes L1, L2, L3, L4 et L5 par des liaisons 20 à 24, ledit réseau 18 permettant de communiquer, par une liaison 25, ligne par ligne, l'état binaire de chacun des capteurs photosensibles H ; et
• un moyen 26 d'évaluation de l'état binaire des capteurs photosensibles H, relié à la liaison 25 et permettant d'extraire les états 1 représentatifs d'une détection d'éclats lumineux EL.

To do this, said identification system SI2 comprises:

• a network 18 of shift registers, connected respectively to lines L1, L2, L3, L4 and L5 by links 20 to 24, said network 18 making it possible to communicate, by a link 25, line by line, the binary state of each photosensitive sensors H; and
• means 26 for evaluating the binary state of the photosensitive sensors H, connected to the link 25 and making it possible to extract the states 1 representative of a detection of light flashes EL.

In another embodiment not shown, the system identification is trained to monitor the electric current consumed by each of said sensors photosensitive H, any increase in said electric current consumed, which is greater than a predefined increase, then indicating a characteristic variation in illumination.

In addition, said identification system SI2 includes plus a means 27 connected by a link 28 to the means 26, for identify said target C which reflects flashes of light EL at constant and predefined time intervals T.

• enregistre toute variation d'éclairement caractéristique ;
• mesure l'intervalle de temps entre deux variations d'éclairement caractéristiques successives détectées ;
• compare l'intervalle de temps ainsi mesuré audit intervalle de temps T prédéfini ; et
• identifie ou non la cible C en fonction de cette comparaison, comme on le verra ci-dessous en référence à la figure 5.

To this end, said means 27:

• records any variation in characteristic illumination;
• measures the time interval between two successive characteristic variations in illumination detected;
• compares the time interval thus measured with said predefined time interval T; and
• identify or not identify the target C as a function of this comparison, as will be seen below with reference to FIG. 5.

Furthermore, said location system SL2 comprises, according to the invention, a network 29 of shift registers connected respectively to columns C1, C2, C3 and C4 of photosensitive detector D2 by links 30 to 33, said network 29 making it possible to transmit in series, in an order predefined, the binary state of all photosensitive sensors H, the order of each photosensitive sensor H in the transmission series being representative of its position on said matrix.

So, we are able to locate the position of everything photosensitive sensor H having a state 1.

Of course, it is possible that only one EL light flash large diameter puts several photosensitive sensors H in their state 1. Also, to be able to realize in such a case a precise localization, the localization system SL2 further comprises, according to the invention, a means of calculation 35 linked by a link 36 to the network 29 and determining a central position from localized positions of all photosensitive sensors H which have detected a EL light burst.

• qui reçoit :
  • par la liaison 36 dédoublée, la position de tous les capteurs photosensibles H ayant détecté un éclat lumineux EL ; et
  • par une liaison 38, l'intensité du signal Vs engendré par un moyen de traitement précisé ci-dessous de chacun desdits capteurs photosensibles H ayant détecté un éclat lumineux EL ; et
• qui calcule, à partir des intensités et des positions ainsi reçues, le barycentre correspondant qui représente la localisation recherchée.

Furthermore, in a particularly advantageous embodiment, the location system SL2 also comprises a calculation means 37:

• Who receives :
  • by the split link 36, the position of all the photosensitive sensors H having detected an EL light flash; and
  • by a link 38, the intensity of the signal Vs generated by a processing means specified below of each of said photosensitive sensors H having detected a light burst EL; and
• which calculates, from the intensities and positions thus received, the corresponding barycenter which represents the location sought.

FIG. 5 is a diagram illustrating, as a function of time t , the different stages of such a process of identification and localization of a target C by means of the detection system SD2.

Preferably, upon detection, the identification system SI2 is on standby and the SL2 location system is out of service.

On a line P1 in FIG. 5, the different illuminations I1 to I6 have been represented detected as a function of time t respectively at times t1 to t6, by the photosensitive detector D2 and corresponding to light flashes EL received.

On a line P2, the identification has been illustrated, by means of the SI2 identification system, among all the illuminations I1 to I6 detected, of those coming from the target C, i.e. those that are separated by a time T. As, on the one hand, the durations T1 between t1 and t2 and T3 between t2 and t3 are less than T, and since, on the other hand, the duration T2 between t1 and t3 is greater than T, the couples I1 / I2, I1 / I3 and I2 / I3 do not correspond to two illuminations reflected by target C.

On the other hand, the duration between times t2 and t4 is equal to T, of course taking into account the margins of error possible. Having thus identified a couple of illuminations I2 and I4 reflected by target C, we can predict the instants t5, t6, ... of the next illuminations I5, I6, ... reflected by said target C, at durations T, 2T, ... after t4, to within a margin of error ME.

We can then activate the location system SI2, during time windows Fe, at said instants t5, t6, ..., so that the latter locates the target C, from the as previously described.

In FIG. 6, one of the photosensitive sensors has been represented. H used in D2 compliant photosensitive detector to the invention.

• une diode photosensible 40 qui est reliée, d'une part, à une tension positive +V et, d'autre part, à la masse Ma par l'intermédiaire d'une résistance R1, et qui est susceptible de transformer l'énergie lumineuse reçue en un signal électrique ; et
• un moyen 41 de traitement des signaux électriques engendrés par la diode photosensible 40.

According to the invention, said photosensitive sensor H comprises:

• a photosensitive diode 40 which is connected, on the one hand, to a positive voltage + V and, on the other hand, to the ground Ma via a resistor R1, and which is capable of transforming the light energy received as an electrical signal; and
• a means 41 for processing the electrical signals generated by the photosensitive diode 40.

• un amplificateur différentiel 42, dont l'entrée non inverseuse (+) est reliée à un point de connexion 43 situé entre la diode photosensible 40 et la résistance R1 et dont l'entrée inverseuse (-) est reliée à la masse Ma par l'intermédiaire d'une capacité Ca ; et
• une résistance R2 reliée, d'une part, à un point de connexion 44 entre la capacité Ca et l'entrée inverseuse (-) et, d'autre part, à la sortie 45 de l'amplificateur différentiel 42.

Said means 41 is produced in the form of a differentiating electrical circuit, of known type, comprising:

• a differential amplifier 42, whose non-inverting input (+) is connected to a connection point 43 located between the photosensitive diode 40 and the resistor R1 and whose inverting input (-) is connected to ground Ma by the intermediate of Ca capacity; and
• a resistor R2 connected, on the one hand, to a connection point 44 between the capacitor Ca and the inverting input (-) and, on the other hand, to the output 45 of the differential amplifier 42.

• d'une part, il renforce les signaux électriques I présentant un temps de montée rapide et correspondant à un éclat lumineux EL détecté par la diode photosensible 40. Il met également en évidence les variations s1 et s2 relativement brusques du bruit de fond lumineux F ; et
• d'autre part, il atténue les signaux électriques présentant une variation temporelle réduite et correspondant à des illuminations faiblement variables en intensité, c'est-à-dire essentiellement ledit bruit de fond lumineux F.

When the photosensitive diode 40 is illuminated, said processing means 41 transforms the electrical signal generated by said photosensitive diode 40 and represented in the form of a voltage Ve in FIGS. 6 and 7, into a signal processed and represented in the form of a voltage Vs. As can be seen in FIG. 7, by comparing the diagrams respectively illustrating the variations of said voltages Ve and Vs, as a function of time t , the processing of the processing means 41 is such that:

• on the one hand, it reinforces the electrical signals I having a rapid rise time and corresponding to a light burst EL detected by the photosensitive diode 40. It also highlights the relatively sudden variations s1 and s2 of the light background noise F; and
• on the other hand, it attenuates the electrical signals having a reduced temporal variation and corresponding to illuminations which are slightly variable in intensity, that is to say essentially said light background noise F.

Thus, thanks to the invention, we are able to evidence of short pulses in light background noise F, which makes it possible to precisely detect EL light flashes of reduced intensity compared to said audit bright background noise F. The photosensitive sensor H allows thus, in particular, to detect pulses with low intensity, emitted or reflected by a target C located at great distance from said photosensitive sensor H and therefore from said flying body M.

• un moyen de binarisation 46 qui est relié par une liaison 47 à la sortie 45 de l'amplificateur différentiel 42 et qui compare ladite tension Vs à ladite sortie 45 à une tension de référence Vo et attribue, en fonction du résultat, un état binaire 0 (si Vs est inférieure à Vo) ou 1 (si Vs est supérieure à Vo) audit capteur photosensible H ; et
• un moyen de mémorisation 48 qui est relié au moyen de binarisation 46 par une liaison 49, qui enregistre l'état binaire déterminé par ce dernier et qui peut transmettre cette information par l'intermédiaire d'une liaison 50.

According to the invention, said photosensitive sensor H further comprises, as shown diagrammatically in FIG. 6:

• binarization means 46 which is connected by a link 47 to the output 45 of the differential amplifier 42 and which compares said voltage Vs to said output 45 with a reference voltage Vo and assigns, as a function of the result, a binary state 0 (if Vs is less than Vo) or 1 (if Vs is greater than Vo) to said photosensitive sensor H; and
• a storage means 48 which is connected to the binarization means 46 by a link 49, which records the binary state determined by the latter and which can transmit this information via a link 50.

Claims (14)

1. Homing head mounted on a flying body (M), intended to determine orders for guiding the said flying body (M) towards a target (C) which emits luminous flashes (EL) and comprising, in particular:

   a target detection system (SD1, SD2) including:

   a photosensitive detector (D1 D2) mounted fixedly on the flying body (M), exhibiting a field capable of covering a predetermined zone of detection of the target (C) and comprising a matrix of photosensitive sensors (H); and

   identification (SI1, SI2) and locating (SL1, SL2) systems for identifying and locating on the matrix of the photosensitive detector (D1, D2) the luminous flashes (EL) emitted by the target (C) in order to locate the latter;

   a source of inertial information (2); and

   a central unit (3) for processing information, linked to the said target detection system (SD1, SD2) and to the said source of inertial information (2) and determining the said guidance orders,

   characterized in that the said target detection system (SD1, SD2) additionally includes a means of focusing (6, 7) which projects onto the said matrix of the photosensitive detector (D1, D2) the image of the scene situated fore of the flying body (M), and comprising if appropriate the luminous flashes (EL) which are emitted by the target (C), in that the said photosensitive detector (D2) includes photosensitive sensors (H) respectively fitted with photosensitive diodes (40) capable of transforming the luminous energy received into an electrical signal, and in that each of the said photosensitive sensors (H) includes, in addition to the said photosensitive diode (40), a means (41) of processing the electrical signals generated by the said photosensitive diode (40), the said means of processing (41) comprising a differentiator electrical circuit which:

   on the one hand, strengthens the electrical signals exhibiting a fast rise time and corresponding to a luminous flash (EL) received by the photosensitive diode (40); and

   on the other hand, attenuates the electrical signals exhibiting slow time variation and corresponding to illuminations which vary only slightly in intensity, of the said photosensitive diode (40).
2. Homing head according to Claim 1,
   characterized in that the said system (SI1) for identifying luminous flashes (EL) includes a photosensitive diode (10) capable of detecting the luminous flashes (EL) originating from the said scene situated fore of the flying body (M) and means (9) capable of determining, from among the said detected luminous flashes (EL), those originating from the target (C).
3. Homing head according to either of Claims 1 and 2,
   characterized in that the said target detection system (SD1) includes a shutter (13) shutting off the field of view of the target locating system (SL1), the said shutter (13) being controlled in such a way as to free the said field of view each time a luminous flash (EL) originating from the said target (C) is expected.
4. Homing head according to Claim 1,
   characterized in that the said system (SI2) for identifying luminous flashes (EL) includes the said photosensitive detector (D2).
5. Homing head according to any one of the preceding claims,
   characterized in that each of the said photosensitive sensors (H) includes a means of binarization (46) making it possible to determine a binary state of the said photosensitive sensor (H), as a function of the signal formed by the said means (41) of processing electrical signals.
6. Homing head according to Claim 5,
   characterized in that each of the said photosensitive sensors (H) includes a means of storage (48) allowing the said binary state to be recorded.
7. Homing head according to any one of Claims 1 and 4 to 6,
   characterized in that the said system (SI2) for identifying luminous flashes (EL) is capable of detecting a characteristic variation in illumination, which is greater than a predefined variation, of at least one of the said photosensitive sensors (H).
8. Homing head according to Claim 7,
   characterized in that the said system for identifying luminous flashes (EL) monitors the electrical current consumed by each of the said photosensitive sensors, any increase in the said consumed electrical current, which is greater than a predefined increase, indicating a characteristic variation in illumination.
9. Homing head according to Claims 7 and 5 or 6,
   characterized in that the said system (SI2) for identifying luminous flashes (EL) monitors the binary state of the said photosensitive sensors (H), any change of the binary state to a state representative of the detection of a luminous flash (EL) indicating a characteristic variation in illumination.
10. Homing head according to Claim 9,
    characterized in that the said system (SI2) for identifying luminous flashes (EL) includes a first network (18) of shift registers, capable of transmitting the binary state of all the photosensitive sensors (H) of the photosensitive detector (D2).
11. Homing head according to any one of Claims 1 to 10,
    characterized in that the said locating system (SL2) makes it possible to locate in the matrix of the photosensitive detector (D2) the position of each photosensitive sensor (H) which detects a luminous flash (EL) .
12. Homing head according to Claims 11 and 5 or 6,
    characterized in that the said locating system (SL2) includes a second network (29) of shift registers, making it possible to transmit in series in a predefined order the binary state of all the photosensitive sensors (H), the order of each photosensitive sensor (H) in the transmission series being representative of its position in the matrix.
13. Homing head according to either of Claims 11 and 12,
    characterized in that the said locating system (SL2) includes a means of calculation (35) making it possible to determine a central position from the located positions of all the photosensitive sensors (H) having detected a luminous flash (EL).
14. Homing head according to Claim 11,
    characterized in that the said locating system (SL2):

    determines the intensity of the signal generated by the means of processing (41) of each of the photosensitive sensors (H) having detected a luminous flash (EL);

    determines the position of each of the said photosensitive sensors (H) having detected a luminous flash (EL) ; and

    calculates, from the intensities and positions thus determined, the corresponding barycentre which represents the sought-after location.

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