DE102007030880B4 - Device for detecting an object scene - Google Patents

Abstract

Device (1) for detecting an object scene with an imaging optical system, comprising
- An entrance optics (2) with a central recess (3),
A number of detector units (6, 7),
- At least one emitter unit (5) for beam emission and
A separation optics (4) arranged in the center recess (3) of the entrance optics (2), the separation optics (4)
a) each having a fiber feed (19 a, 19 b) is optically connected to the emitter unit (5) and with a on the target radiation of the emitter unit (5) responsive detector unit (6) and
b) comprises a layer (18) reflecting on both sides, wherein a beam directed via the fiber feed (19a) from the emitter unit (5) can be directed in the direction of the object scene via a first side of the layer (18) and over the second side of the layer (18). 18), a beam entering via the entry optics (2) for coupling into the fiber feed (19b) optically connected to the detector unit (6) can be guided.

Description

The invention relates to a device for detecting an object scene, as well as a guided missile with such a device.

A device for detecting an object scene is, for example, from EP 1 241 486 B1 known. The device described therein comprises an imaging optical system with a Cassegrain optics entrance optics, which has a central recess, wherein in the center recess a separation optics is arranged. The central recess forms an aperture separation for an incident radiation from the outside, which is supplied via a beam path of a detector unit, and for the light of a laser emitter, which is passed via a fiber feed to the separation optics and emitted from there predominantly to the outside from. About the separation optics, a small proportion of the light emitted by the laser emitter light is diverted and returned as a reference signal to the detector unit.

Furthermore, from the DE 33 17 232 A1 a device for detecting an object scene known, which in contrast to the device described above from the EP 1 241 486 B1 a laser transceiver system having separate receiving units, but laterally spaced from the central receiving beam path are arranged.

From the DE 101 17 147 A1 is a dual-mode seeker is known in which laser radiation is sent via an optical fiber and a transmission optics directly in the direction of the object scene and the reflected laser beam from a target via a dichroic mirror is deflected to a detector.

From the US 4 325 638 A is an electro-optical distance measuring device is known in which the transmission radiation is guided over an optical fiber and deflected by a catheter side of a prism in the measuring direction and in which the receiving radiation is deflected from the other side of the catheter prism in the direction of a second optical fiber and passed through this to the detector.

A first object of the invention is to provide a compact device for detecting an object scene, which has both an active and a passive optical sensor system.

Another object of the invention is to provide a guided missile, which is provided with a search head as compact as possible, which has both an active and a passive optical sensor system.

The first object is achieved with a device for detecting an object scene according to claim 1.

The invention is based on the consideration that a passive sensor system with an active sensor system integrated in the area of the entrance optics can be displayed integrally by using the separation optics to spectrally filter out the beams radiated from the emitter unit and reflected back from the total radiation entering via the common receive beam path and via a Fiber supply to be fed to a separate detector unit. The residual spectrum of the input radiation is forwarded to one or more detector unit (s) of the passive sensor system. At the same time, the separation optics is designed to deflect the radiation of the emitter unit, which is conducted via a further fiber feed, in such a way that it is emitted along the central optical axis of the device. The separation optics thus assumes a dual function.

Preferably, the entrance optics is designed as a Cassegrain optic with a concave-parabolic main mirror and a convex-hyperbolic capture mirror. An incident radiation passes over the primary mirror to the secondary mirror and from there into the receiving beam path, which leads in a central recess through the primary mirror. Due to this double deflection, the length of a Cassegrain optic is relatively small. When using Cassegrain optics as entry optics already has the main mirror on a central recess, in front of the separation optics can be arranged with negligible loss of imaging. The output beam path is directed by the separation optics through a further center recess of the capture mirror along the central optical axis to the target area.

In an advantageous embodiment of the device, a focusing optics is provided for bundling a beam emitted by the emitter unit. The emitted beam is radiated coaxially to the central optical axis of the device, so that such a focusing optic is arranged concentrically in the emission direction in the region of the central recess and the optically deflecting separation optics are downstream in the emission direction.

The separation optics has a layer reflecting on both sides, wherein a beam directed via the fiber feed from the emitter unit can be directed to the emitting optics via a first side of the layer, and a beam entering via the inlet optics via the second side of the layer Coupling in the optically connected to the detector unit fiber feed is steerable.

For this purpose, in an expedient refinement, the layer reflecting on both sides is arranged at an angle of 45 ° to the central optical axis of the device so that the emission beam strikes the first side of the reflective layer orthogonally to the central optical axis and coaxial with the central optical axis in a direction of emission is steered.

If, in such an arrangement of the bilaterally reflecting layer, the partial spectrum of the input radiation, which essentially corresponds to the spectral range of the emission signal, is directed along the central optical axis onto the opposite second side of the reflective layer, then the fiber feed leading to the detector unit of the active sensor system , be arranged opposite to the fiber feed from the emitter unit and orthogonal to the central optical axis.

By this arrangement, a particularly simple and thus compact realization of the separation optics is possible.

In a suitable development of the separation optics, the layer reflecting on both sides is designed as a partial surface of a prism or as an inner surface of a beam splitter cube.

Preferably, the separation optics comprises a partially reflecting layer, via which a radiation incident on the inlet optics can be guided to the separation optics with a predetermined frequency. Such a partially reflecting layer is given for example by a dichroic filter which reflects the desired frequency and allows the remaining frequencies to pass substantially.

Such a partially reflecting layer is preferably arranged in the region of the central recess in a plane orthogonal to the central optical axis, and expediently such that the incident input radiation is reflected back to the separation optics at a frequency in the region of the emission frequency in the direction of the central optical axis. The remaining frequencies pass through the partially reflecting layer and travel along the input beam path to the detector units which are assigned to the passive sensors.

Conveniently, the bilaterally reflecting layer and / or the partially reflecting layer is specially designed for reflection in a narrow frequency band, in particular for reflection of monochromatic light with a predetermined frequency. In this case, the frequency is predetermined in particular by the emitter unit.

As an emitter unit, a substantially monochromatic light source, in particular a laser source, is preferably provided. Monochromatic light is particularly advantageous for the active sensors since the backscattered emission signals are particularly easy to identify and filter out. By filtering out only a narrow frequency band, the complementary spectrum is limited only slightly and thus the passive sensor, which detects signals from this complementary spectrum, at most slightly impaired.

The detector unit optically connected to the separation optics via a fiber feed is expediently provided for detecting the radiation emitted by the emitter unit, in particular for transit time measurement of an emitted radiation signal. Therefore, the detector unit is preferably designed for evaluating, in particular, the signal frequencies in a narrow frequency band around the predetermined frequency of the emitter unit. From the determination of the transit time of an emission signal, the distance to a signal reflecting the obstacle can be determined.

Suitably, the emitter unit and the or each detector unit are arranged on a rolling frame with a roll axis, against which the entrance optics is rotatably mounted about a pivot axis substantially orthogonal to the pivot axis. In particular, the optical fibers can thus be laid from the separation optics to the emitter unit / detector unit without further optical connecting elements such as mirrors, prisms or the like.

In an alternative embodiment of the device, a structure-fixed installation of the emitter unit and the or each detector unit can be realized.

Advantageously, an evaluation unit is provided for signal evaluation of the radiation signals received at the or each detector unit. In particular, such an evaluation unit is designed to determine the transit time of a light signal emitted by the emitter unit. Furthermore, the evaluation unit is suitably designed to evaluate the signals received via the further detector units assigned to the passive sensors.

Preferably, a control unit is provided which is designed to activate the emitter unit as a function of evaluation data of the evaluation unit.

For determining the distance of an obstacle, the evaluation data of the passive sensors are initially provided. In particular, the infrared radiation emitted by an object is used for object detection. However, the identification and in particular the distance determination is not sufficiently accurate for each application. From a predefinable distance threshold, which is determined from the detector data of the passive sensor, the control unit then activates the emitter unit, so that a relatively accurate distance information can be obtained by the reflected back emission signals. This is then evaluated and is available to the control unit for continued process decisions.

The second object is achieved with a guided missile according to claim 12.

By means of this embodiment, in particular a compact laser proximity sensor system in conjunction with a passive sensor system, in particular a passive infrared sensor system, can be realized.

Due to the compact design of the device, this is ideal for use in a seeker head for guided missiles. By integrating the separation optics into the central recess and connecting them with fiber feeds, the space available in a guided missile for a seeker head can be optimally utilized. Emitter unit and on target radiation of the emitter unit responsive detector unit can be arranged at locations that do not necessarily have to be located in the foremost region of a seeker, since the signal forwarding emitted or to be detected radiation via the fiber feeds.

In the following, an embodiment of the invention will be discussed with reference to a drawing. Show

1 a device in longitudinal section along the central optical axis in a schematic representation,

2 a partial section of the device according to 1 in the field of entrance optics with optical fiber feeds and with a schematic representation of the input beam path, and

3 a guided missile with a structural housing, a coaxially disposed within the structural housing and rotatably mounted about a roll axis rolling frame and a device according to 1 ,

Corresponding parts are provided in the figures with the same reference numerals.

In 1 is a device 1 in a longitudinal section along the central optical axis x shown schematically.

The device 1 includes an entrance optics 2 with a central recess 3 , one in the middle of the recess 3 arranged separation optics 4 , a laser emitter unit 5 and at least two detector units 6 . 7 , The laser emitter unit 5 and the detector unit 6 form part of an active sensor system 8th out. The detector unit 7 is a passive sensor 9 assigned. The entrance optics 2 is designed as a Cassegrain optic, with a concave parabolic main mirror 10 and with a convex hyperbolic catch mirror 11 , The main mirror 10 and the secondary mirror 11 each have circular recesses 12 respectively. 13 on top, the center recess 3 depending on the position with respect to the central optical axis x limit. A radiation incident along the central optical axis 14 is first at the main mirror 10 reflected and to the secondary mirror 11 passed and is there in the central area of the central recess 3 Reflected back for further processing.

The separation optics 4 includes a dichroic plate 15 , a collimation lens 16 and a prism 17 with a triangular cross section, which has a coating reflecting on both sides 18 on the hypotenuse side. With the prism 17 optically connected to the end are two optical fibers 19a and 19b , wherein the optical fiber 19a to the laser emitter unit 5 leads, and the optical fiber 19b to the detector unit 6 leads. The separation optics 4 is a focusing lens 20 upstream, which is used for the targeting of an emission beam 21 is trained. In the middle recess 3 in the area between the dichroic plate 15 and the detector unit 7 are other optical means 22 arranged, which are optionally formed for optical selection / branching. Outward is the device 1 through a curved glass dome 23 completed and is protected by this from external influences.

The incident along the central optical axis (inverse x direction) radiation 14 , For example, an infrared radiation that is above the main mirror 10 and the catch mirror 11 the Cassegrain optics is directed into the middle recess, the dichroic plate passes 15 and propagates as input radiation 14a in the area in which further schematically drawn optical means 22 are arranged, and is by these optical means 22 on the detector unit 7 that of the passive sensors 9 is assigned, focused. In the detector unit 7 becomes the input radiation 14a recorded and the optical data obtained from it 24 are sent to an evaluation unit 25 transmitted. There, a situation picture is created, in which in particular the Distance to obstacles and / or goals is coded. The situational picture has blurring that results from the limit of interpretability accuracy of the (infrared) radiation emitted by the obstacles and / or targets. If the distance to an obstacle or a destination obtained from the situation image falls below a stored threshold value at which more precise distance information must be made available, data will be transmitted via a data link 26 a control unit 27 informed, which by a control pulse 28 the laser emitter unit 5 activated. The laser emitter unit 5 emits pulses of monochromatic light at a known frequency. About the optical fiber 19a this light becomes the separation optics 4 passed, and meets after exiting the optical fiber 19a on the first side of the catheter of the prism 17 , which in the illustration is substantially parallel to the central optical axis x. While passing through the prism 17 the emitted light is inside of the two-sided reflective coating 18 on the hypotenuse side of the prism 17 reflects and acts as an emission beam 21 on the second side of the catheter of the prism 17 out. Through the focusing lens 20 becomes the emission beam 21 bundled, and emerges in the representation in the direction of the central optical axis x forward from the device 1 out.

Once the laser emitter unit 5 are activated in the entrance optics 2 incident radiation 14 Shares of the emission beam backscattered and / or reflected back to obstacles and / or targets 21 contain. These shares penetrate the main mirror 10 and the catch mirror 11 the Cassegrain optics up to the dichroic plate 15 in front. The dichroic plate 15 is adapted to the frequencies of the total spectrum, which are in a narrow band around the emission frequency of the laser emitter unit 5 lie, as partial radiation 14b reflect back. Thus, the backscattered and / or reflected back portions of the emission beam 21 at the dichroic plate 15 from the remaining incident radiation 14 filtered off and are used as partial radiation 14b from the outside to the coating reflecting on both sides 18 on the hypotenuse side of the prism 17 steered, there deflected by substantially 90 °, then in the optical fiber 19b coupled in and over the optical fiber 19b to the detector unit 6 transmitted. The detector unit 6 is especially for the detection of light components of the emission beam 21 trained, and transmits the optical data obtained therefrom 30 to the evaluation unit 25 , Based on a pulse modulation of the emission beam 21 can in the evaluation unit 25 the light transit time of the emission beam 21 determined and from the distance of the device to the reflecting obstacle are calculated. That from the passive sensors 9 known situation image is thus spatially specified locally.

2 shows a perspective view of a partial section of the device according to 1 in the field of entry optics 2 with the optical fibers 19a and 19b , Visible are the entrance optics 2 and the center recess 3 , The main mirror 10 and the secondary mirror 11 are over a linkage 31 connected and held together. In the area of the middle recess 3 between the main mirror 10 and the secondary mirror 11 is the separation optics 4 arranged the the dichroic plate 15 , the collimation lens 16 and the prism 17 comprising the triangular-shaped cross section, wherein the prism 17 on the hypotenuse side with a coating or coating reflecting on both sides 18 is coated. Also visible in a schematic representation of the beam path of the emission beam 21 , The emission beam 21 is first made from the optical fiber 19a decoupled and through the prism 17 passed, taking it to the layer 18 inside with respect to the prism 17 is reflected by about 90 °. After exiting the prism 17 propagates the emission beam 21 through the middle recess 13 the capture mirror 11 , is through the focusing lens 20 bundled and enters the front of the device 1 out.

The parts of the emission beam reflected back from an obstacle 21 occur with the incident radiation 14 in the entrance optics 2 one, as partial radiation 14b at the dichroic plate 15 reflected, on the coating 18 on the outside with respect to the prism 17 reflected by about 90 °, so that the partial radiation 14b in the optical fiber 19b is coupled. The remaining parts of the spectrum of incident radiation 14 happen as input radiation 14a the dichroic plate 15 unhindered and are through the middle recess 12 the main mirror 10 forwarded to the continued information processing (cf. 1 ).

Furthermore, the orientation of the central optical axis x is displayed. Visible in this illustration is the slight tilt of the orientation of the emission beam 21 relative to the central optical axis x, which results from the entrance optics 2 about a lying in the plane perpendicular to the central optical axis x orthogonal pitch axis y is pivotable. This is in 3 explained in more detail.

3 shows a guided missile 32 with a structural housing 33 one within the structure housing 33 coaxially arranged and about a roll axis x 'rotatably mounted rolling frame 34 and schematically a device 1 to 1 , The roll axis is arranged coaxially to the central optical axis x. Furthermore, a bogie 35 formed, which is opposite the rolling frame 34 is mounted pivotably about the pivot axis y 'by 180 °.

Because of the rolling frame 34 opposite the structure housing 33 about the roll axis x 'is rotatable by 360 °, the pivot axis y' coaxial with any, orthogonal to the central optical axis x lying pitch axis y - which in the selected representation perpendicular out of the image plane align - align. The device 1 spreads both on the bogie 35 , in which in particular the entrance optics 2 is arranged, as well as on the rolling frame, in which in particular the laser emitter unit 5 , the detector units 6 and 7 , as well as the evaluation unit 25 and the control unit 27 is arranged. As information connecting elements between the entrance optics 2 on the bogie 35 and the laser emitter unit 5 or the detector unit 6 act the optical fibers 19a respectively. 19b , Due to the flexibility of the optical fibers 19a and 19b becomes the pivotability of the bogie 35 opposite the rolling frame 34 not impaired. In an alternative structurally fixed arrangement of the laser emitter unit 5 or the detector unit 6 would have to be provided further optical transmission elements, since a direct connection via optical fibers would then no longer be possible.

LIST OF REFERENCE NUMBERS

1

contraption

2

admission optics

3

central recess

4

separation optics

5

Laser emitter unit

6

detector unit

7

detector unit

8th

active sensors

9

passive sensors

10

main mirror

11

Fangspiegel

12

Center recess of the main mirror

13

Center recess of the catching mirror

14

incident radiation

14a

input radiation

14b

partial radiation

15

Dicroitic plate

16

collimating lens

17

triangular prism

18

double-sided reflective layer

19a

optical fiber

19b

optical fiber

20

focusing lens

21

emission beam

22

further optical means

23

glass dome

24

optical data

25

evaluation

26

Data Connection

27

control unit

28

control pulse

30

optical data

31

linkage

32

Missile

33

structure housing

34

roll frame

35

bogie

x

central optical axis

x '

roll axis

y

pitch axis

y '

swivel axis

e

to the central optical axis orthogonal plane

Claims (12)

Contraption ( 1 ) for detecting an object scene with an imaging optical system, comprising - an entrance optics ( 2 ) with a central recess ( 3 ), - a number of detector units ( 6 . 7 ), - at least one emitter unit ( 5 ) for beam emission and - one in the middle recess ( 3 ) of the entrance optics ( 2 ) arranged separation optics ( 4 ), wherein the separation optics ( 4 ) a) each with a fiber feed ( 19a . 19b ) with the emitter unit ( 5 ) and with a target radiation of the emitter unit ( 5 ) responsive detector unit ( 6 ) is optically connected and b) a double-sided reflective layer ( 18 ), wherein over a first side of the layer ( 18 ) via the fiber feed ( 19a ) from the emitter unit ( 5 ) directed in the direction of the object scene is steerable and over the second side of the layer ( 18 ) via the entrance optics ( 2 ) incoming beam for coupling into the with the detector unit ( 6 ) optically connected fiber feed ( 19b ) is steerable. Contraption ( 1 ) according to claim 1, characterized in that the entry optics ( 2 ) is designed as a Cassegrain optic, comprising a concave-parabolic main mirror ( 10 ) and a convex-hyperbolic secondary mirror ( 11 ). Contraption ( 1 ) according to claim 1 or 2, characterized in that a focusing optics ( 20 ) for bundling a beam emitted by the emitter unit ( 21 ) is provided. Contraption ( 1 ) according to one of claims 1 to 3, characterized in that the double-sided reflective layer ( 18 ) as a partial surface of a prism ( 17 ) or formed as an inner surface of a beam splitter cube. Contraption ( 1 ) according to one of claims 1 to 4, characterized in that the separation optics ( 4 ) a partially reflecting layer ( 15 ) via which one via the entrance optics ( 2 ) incident radiation ( 14b ) with predetermined frequency back in the direction of the object scene is steerable. Contraption ( 1 ) according to one of claims 1 to 5, characterized in that the double-sided reflective layer ( 18 ) and / or the partially reflecting layer ( 15 ) is formed to a narrow band reflection, in particular to a reflection of monochromatic light with a predetermined frequency. Contraption ( 1 ) according to one of claims 1 to 6, characterized in that as an emitter unit ( 5 ) a substantially monochromatic light source, in particular a laser light source, is provided. Contraption ( 1 ) according to one of claims 1 to 7, characterized in that the separation optics ( 4 ) via a fiber feed ( 19b ) optically connected detector unit ( 6 ) for the detection of the emitter unit ( 5 ) emitted radiation is provided, in particular for transit time measurement of an emitted radiation signal ( 21 ). Contraption ( 1 ) according to one of claims 1 to 8, characterized in that the emitter unit ( 5 ) and the or each detector unit ( 6 . 7 ) on a rolling frame ( 34 ) are arranged with a roll axis (x '), opposite which the entrance optics ( 2 ) is rotatably mounted about a pivot axis (y ') substantially orthogonal to the roll axis (x'). Contraption ( 1 ) according to one of claims 1 to 9, characterized in that an evaluation unit ( 25 ) for signal evaluation at the or each detector unit ( 6 . 7 ) received radiation signal data ( 24 . 30 ) is provided. Contraption ( 1 ) according to one of claims 1 to 10, characterized in that a control unit ( 27 ) for activating the emitter unit ( 5 ) depending on evaluation data ( 26 ) of the evaluation unit ( 25 ) is provided. Guided missile ( 32 ), comprising a structural housing ( 33 ), one within the structural housing ( 33 ) coaxially arranged and about a roll axis (x ') rotatably mounted rolling frame ( 34 ) and a device ( 1 ) according to one of claims 1 to 11.

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