An observation system comprising a laser remote sensing device and a device for orienting a laser beam field along a plurality of directions

Abstract

This observation system includes a laser beam guidance device (18) and a laser remote sensing device (8) configured to perform a range measurement on a range segment (12). The guidance device (18) is configured to redirect a laser beam emitted onto the range segment (12) and direct it along a plurality of directions from an observation plane of the observation system. The guidance device (18) includes at least one movable mirror (32) rotating about itself, configured to direct said laser beam along said plurality of directions. An axis of rotation of said movable mirror (32) and a longitudinal axis of said range segment are non-parallel and non-orthogonal. Figure for the abbreviation: Fig 6

Description

Title of the invention: Observation system comprising a laser remote sensing device and a device for orienting a laser beam field along a plurality of directions. Technical field

[0001] The invention relates to an observation system comprising a laser remote sensing device, or LiDar device for "Light Detection And Ranging" in English, and a device for orienting a field of laser beams along a plurality of directions of an observation plane of the observation system. Previous techniques

[0002] The prior art of LiDar detectors used in the automotive sector is known which are capable of performing a telemetry measurement for an observation field adapted to the automotive field, for example an observation field of more than 90 degrees horizontally and more than 20 degrees vertically as illustrated in [Fig.1].

[0003] For certain applications, and in particular in the aeronautical field, it is sometimes necessary to carry out laser rangefinding measurements, or LiDar measurements, over a 360-degree horizontal field of view while maintaining a field of view of at least 10 degrees vertically, and at least 40 degrees vertically for certain defense applications.

[0004] To obtain such an observation field, one solution is to juxtapose several known LiDar detectors and orient them in different horizontal directions so as to cover 360 degrees horizontally.

[0005] Increasing the number of LiDar detectors increases the associated costs, the mass carried by the aircraft, and the complexity of the telemetry measurement.

[0006] Another solution consisting of placing an inclined mirror on the optical path of a laser source is illustrated in Figures 2 and 3. These Figures 2 and 3 illustrate a laser 2 directed along an axis [OX] of an orthonormal frame (O, X, Y, Z) striking a first rotating mirror 4.

[0007] The first rotating mirror 4 is parallel to the Y-axis and is free to rotate about the [OY] axis, O being the center of the rotating mirror 4. The rotational movement of the first rotating mirror 4 forms, from the laser 2 directed along the [OX] axis, a set of reflections of the laser 2 onto the first rotating mirror 4, the set being directed at least partially along the [OZ] axis. This set of reflections constitutes a telemetry segment on which the telemetry measurement is performed.

[0008] The telemetry segment is directed towards a second rotating mirror 6 which forms an angle of 45 degrees with the plane (O, X, Y) and which is movable in rotation around the axis [OZ],

[0009] The second rotating mirror 6 has undergone a 90-degree rotation about the axis [OZ] between Figures 2 and 3. With reference to [Fig. 2], the telemetry segment reflected by the second rotating mirror 6 allows for a telemetry measurement to be performed on a vertical segment. With reference to [Fig. 3], the telemetry segment reflected by the second rotating mirror 6 allows for a telemetry measurement to be performed on a horizontal segment.

[0010] During the rotational movement around the axis [OZ] of the second rotating mirror 6, the telemetry segment allows telemetry measurements to be taken along a segment whose direction and orientation vary. A circle C and segments Sn, Ss, Se, and So schematically illustrate in [Fig. 3] the telemetry measurements taken as a function of the north, south, east, and west orientations of the second rotating mirror 6, respectively. Segments Sn and Ss are vertical. Segments Se and So are horizontal.

[0011] Figures 2 and 3 therefore illustrate a difficulty encountered in carrying out laser rangefinding measurements over such a 360-degree horizontal field of view, namely a switching of rangefinding measurements between the purely vertical and purely horizontal directions during the rotation of the second rotating mirror 6 which does not allow a sufficient vertical field of view to be maintained, in particular for the horizontal segments Se and So.

[0012] Furthermore, rotating the laser 2 and the first rotating mirror 4 around the axis [OZ] would require, for example, rotating the power electronics of the laser 2 and a collector associated with the laser 2, which would again increase the complexity of the range measurement.

[0013] It is also noted that, from the position of the second rotating mirror 6 illustrated in [Fig.2], rotating the second rotating mirror 6 around a longitudinal axis of the rotating mirror 6 would result in an observation field similar to the observation field illustrated in [Fig.1], the telemetry segment allowing, for a position of the second rotating mirror 6, a telemetry measurement to be taken on a vertical line of the observation field of [Fig.1]. Description of the invention

[0014] The present invention therefore aims to overcome all or part of the aforementioned drawbacks, to provide an observation system suitable for performing telemetry measurements in a plurality of directions, in particular from an observation plane, by in particular from a fixed laser source and more specifically without using a rotating collector associated with the fixed laser source.

[0015] Another objective of the invention is not to use simultaneously a first plurality of laser sources juxtaposed along a first direction and a second plurality of laser sources juxtaposed along a second secant direction, in particular orthogonal to the first direction.

[0016] An additional objective of the invention is to limit the use of complex rotational movements, in particular the use of free mirrors rotating around several axes of rotation.

[0017] The present invention relates to an observation system comprising a laser radiation guidance device and a laser remote sensing device which is configured to perform a telemetry measurement on a telemetry segment.

[0018] The orientation device is configured to reorient a laser beam that is emitted on the telemetry segment and direct it along a plurality of directions from an observation plane of the observation system.

[0019] The orientation device includes at least one movable mirror rotating on itself which is configured to direct said laser beam in said plurality of directions.

[0020] A rotation axis of said movable mirror and a longitudinal axis of said telemetry segment are not parallel and not orthogonal.

[0021] Said telemetry segment corresponds to a portion of object space on which the telemetry measurement is performed. The orientation device capable of reorienting said laser beam, which is emitted onto the telemetry segment, and of directing it along said plurality of directions of the observation plane makes it possible to perform telemetry measurements along said plurality of directions of the observation plane.

[0022] The angle formed between the axis of rotation of said movable mirror and the longitudinal axis of said telemetry segment, which are neither parallel nor orthogonal, prevents remote sensing measurements from switching between purely vertical and purely horizontal directions when a line of sight of the observation system is oriented. This non-zero angle, in particular, allows the use of a single telemetry segment to perform remote sensing measurements along the plurality of directions of the observation plane of the observation system.

[0023] In other words, said telemetry segment forms an angle with the observation plane of the observation system which is between 0 and 90 degrees. An interval of values ​​designated by the expression "between a and b" represents the domain of values ​​going from more than a to less than b (i.e., excluding bounds a and b).

[0024] According to a first design, the remote sensing device may include a fixed laser source, a scanning mirror and a remote sensing element configured to perform the telemetry measurement on the telemetry segment.

[0025] According to a second design, the remote sensing device may include at least one fixed laser source, in particular a plurality of fixed laser sources that are juxtaposed, and a plurality of remote sensing elements configured to perform the telemetry measurement on the telemetry segment.

[0026] The remote sensing device may further include optical components.

[0027] The orientation device may include a first orientation mechanism capable of directing said laser radiation, which is emitted on the telemetry segment, towards a second orientation mechanism of the orientation device.

[0028] The second orientation mechanism may be equipped with said movable mirror which is capable of reorienting said laser radiation, which is emitted on the telemetry segment and then oriented by the first orientation mechanism, according to said plurality of directions.

[0029] The second orientation mechanism is capable of reorienting said laser radiation, which is emitted on the telemetry segment and then oriented by the first orientation mechanism, along a plurality of directions of the observation plane of the observation system and in particular along the four cardinal directions north - south - east - west of the observation plane of the observation system.

[0030] By "capable of reorienting said laser beam in the north cardinal direction," it is understood that said laser beam, reoriented by the second orientation mechanism, is directed towards the north cardinal point of the observation plane of the observation system to perform a telemetry measurement on a telemetry segment. Similarly, by "capable of reorienting said laser beam in the south cardinal direction," it is understood that said laser beam, reoriented by the second orientation mechanism, is directed towards the south cardinal point of the observation plane of the observation system to perform a telemetry measurement on a telemetry segment, the south cardinal point being opposite the north cardinal point with respect to the observation system in the observation plane of the observation system.

[0031] By "capable of reorienting said laser beam in the cardinal direction east," it is understood that said laser beam, reoriented by the second orientation mechanism, is directed towards the cardinal point east of the observation plane of the observation system to perform a telemetry measurement on a telemetry segment. Similarly, by "capable of reorienting said laser beam in the cardinal direction west," it is understood that said laser beam, reoriented by the second orientation mechanism, is directed towards the cardinal point west of the observation plane of the observation system to perform a telemetry measurement on a telemetry segment, the cardinal point west being opposite at the cardinal point north relative to the observation system in the observation plane of the observation system.

[0032] The north-south and east-west axes are perpendicular in the observation plane of the observation system.

[0033] Advantageously, the first orientation mechanism is movable at least between a first position in which the first orientation mechanism directs said laser radiation, which is emitted on the telemetry segment, towards the second orientation mechanism in a first orientation direction and a second position in which the first orientation mechanism directs said laser radiation, which is emitted on the telemetry segment, towards the second orientation mechanism in a second orientation direction.

[0034] Advantageously, said movable mirror of the second orientation mechanism is movable in rotation on itself at least between a first position in which said movable mirror reorients said laser radiation, which is emitted on the telemetry segment and then oriented by the first orientation mechanism, along a first direction of the observation plane and a second position in which said movable mirror reorients said laser radiation, which is emitted on the telemetry segment and then oriented by the first orientation mechanism, along a second direction of the observation plane.

[0035] Preferably, when the first orientation mechanism is in its first position, said movable mirror of the second orientation mechanism is capable of reorienting said laser radiation, which is emitted on the telemetry segment and then oriented by the first orientation mechanism, at least in a direction called "north" of the observation plane of the observation system and in a direction called "west" of the observation plane of the observation system.

[0036] Preferably, when the first orientation mechanism is in its second position, said movable mirror of the second orientation mechanism is capable of reorienting said laser radiation, which is emitted on the telemetry segment and then oriented by the first orientation mechanism, at least in a direction called "east" of the observation plane of the observation system and in a direction called "south" of the observation plane of the observation system, the "north-south" direction being orthogonal to the "east-west" direction.

[0037] Optionally, the first and second orientation directions form an angle of 90 degrees with each other.

[0038] According to one embodiment, the first orientation mechanism comprises first, second and third mirrors which are movable in rotation together.

[0039] The first mirror can be arranged so as to direct said laser radiation, which is emitted on the telemetry segment of the remote sensing device, towards the second mirror.

[0040] The second mirror can be arranged so as to direct said laser radiation, which is emitted on the telemetry segment and then directed by the first mirror, towards the third mirror.

[0041] The third mirror can be arranged so as to direct said laser radiation, which is emitted on the telemetry segment and then directed successively by the first mirror and by the second mirror, towards said movable mirror of the second orientation mechanism.

[0042] Optionally, the second mirror is parallel to the first mirror, the third mirror being inclined with respect to the second mirror, in particular at an angle of 90 degrees.

[0043] The phrase "the second mirror is parallel to the first mirror" means that the principal axis of the first mirror is parallel to the principal axis of the second mirror.

[0044] The term "the third mirror is inclined relative to the second mirror at an angle of 90 degrees" means that the principal axis of the second mirror forms an angle of 90 degrees with the principal axis of the third mirror.

[0045] Advantageously, the movable mirror of the second orientation mechanism comprises at least two opposite faces that are reflective. Alternatively, the second orientation mechanism may comprise any other optical component suitable for orienting a line of sight in space.

[0046] Advantageously, the angle formed between the axis of rotation of said movable mirror and the longitudinal axis of said telemetry segment is between 10 and 80 degrees, in particular between 20 and 70 degrees, more particularly between 30 and 60 degrees, and even more particularly between 40 and 50 degrees.

[0047] According to a preferred embodiment, the angle formed between the axis of rotation of said rotating movable mirror and the longitudinal axis of said telemetry segment is 45 degrees.

[0048] In a particular embodiment, the observation system further includes a diasporameter arranged on the path of said laser radiation, which is emitted on the telemetry segment, between the orientation device and the remote sensing device.

[0049] This particular embodiment makes it possible to perform a scanning function in a restricted area of ​​space with the observation system which is then able to perform a telemetry measurement on this restricted area of ​​space.

[0050] Advantageously, the observation system comprises a collimation assembly arranged along the path of said laser beam between the orientation device and the remote sensing device, the collimation assembly being equipped with a plurality of optical components centered on a collimation axis of the collimation assembly.

[0051] Optionally, the observation system further includes a diaphragm arranged on the path of said laser beam, in particular between the first orientation device and the second orientation device. Brief description of the drawings

[0052] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example and made with reference to the accompanying drawings in which:

[0053] [Fig-1] is a schematic representation of an observation field of a LiDar detector adapted to the automotive field according to the prior art;

[0054] [Fig.2] and [Fig.3] are schematic representations of the reorientation of a line of sight of a telemetry segment according to the prior art;

[0055] [Fig.4] is a schematic representation of an angle between an axis of rotation of a movable mirror and a longitudinal axis of a telemetry segment;

[0056] [Fig.5] is a schematic representation of an observation field obtained by rotation of the movable mirror of [Fig.5]; and

[0057] [Fig.6], [Fig.7], [Fig.8] and [Fig.9] are views of an observation system according to an embodiment of the invention, when the first and second orientation mechanisms are in different positions. Detailed description

[0058] Figure 4 illustrates a laser remote sensing device, or LiDAR device, for an observation system. A coordinate system (O, X, Y, Z) is shown to clarify certain orientations.

[0059] The laser remote sensing device 8 comprises a plurality of laser sources juxtaposed longitudinally along a longitudinal axis, each capable of emitting laser radiation towards a rotating mirror 10. The laser radiation from the laser sources is emitted from a telemetry segment 12 into a space referred to as the "detector" or "image," which allows a portion of a space referred to as the "object" in a scene observed by the observation system to be addressed in order to perform a telemetry measurement. The laser sources are juxtaposed such that the telemetry segment 12 extends along a longitudinal axis which, in this case, lies in the (O, X, Z) plane.

[0060] The remote sensing device 8 is capable of performing a telemetry measurement on the telemetry segment 12. In particular, each laser source is associated with a remote sensing element or collector (not shown) so that the remote sensing device 8 is capable of performing a telemetry measurement for each laser source.

[0061] The movable mirror 10 is free to rotate about an axis of rotation which is parallel to the Y axis. The laser radiation emitted on the telemetry segment is reflected on the movable mirror 10 during its rotational movement to form a laser beam field 14.

[0062] The rotation axis of the movable mirror 10 and the longitudinal axis of the telemetry segment 12 are neither parallel nor orthogonal. In other words, the angle α between the rotation axis of the movable mirror 10 and the longitudinal axis of the telemetry segment is non-zero and different from 90 degrees. More precisely, the longitudinal axis of the telemetry segment forms a non-zero angle with the X-axis, forms a non-zero angle with the Z-axis, and forms a 90-degree angle with the Y-axis. Even more precisely, the angle α between the rotation axis of the movable mirror 10 and the longitudinal axis of the telemetry segment 12 is 45 degrees.

[0063] The field of view of the remote sensing device 8 resulting from this non-zero angle α and the rotation of the movable mirror 10 is illustrated in [Fig. 5]. This field of view corresponds, in a plane parallel to the (O, Y, Z) plane, to the positions in space towards which the laser beam field 14 is directed and therefore to positions in space at which the remote sensing device 8 is able to perform telemetry measurements without further reorientation of the laser beam field 14.

[0064] With reference to [Fig.5], and in comparison with the observation field of the LiDar detector according to the prior art illustrated in [Fig.1], the observation field of the remote sensing device 8 is deformed as a consequence of the non-zero angle a, this deformation allowing the reorientation of this observation field in different directions without total flipping between purely vertical and purely horizontal directions.

[0065] A telemetry measurement need 16, illustrated in figures 1 and 5 by a rectangle and which here corresponds to the need for an observation field of 90 degrees horizontally and 20 degrees vertically, is reached with the non-zero angle a which is here 45 degrees.

[0066] With reference to Figures 6 to 9, and so that the observation system is capable of performing panoramic rangefinding measurements by reorienting the laser beam field 14 emitted by the remote sensing device 8 along a plurality of directions of an observation plane of the observation system, the observation system further comprises a laser beam orientation device 18 for the laser radiation emitted by the remote sensing device 8. This orientation device 18 replaces the movable mirror 10 of [Fig. 4]. The orientation device 18 is capable of reorienting the laser radiation emitted on the rangefinding segment 12 and directing it along a plurality of directions of the observation plane of the observation system.

[0067] The observation device 18 includes a collimation assembly 20, a first orientation mechanism 22, and a second orientation mechanism 24.

[0068] The collimation assembly 20 is equipped with a plurality of optical components centered on a collimation axis, which is here an axis of revolution, of the collimation assembly 20, the collimation axis being parallel here to the Y-axis of [Fig. 4]. Alternatively, the collimation assembly could comprise cylindrical lenses, the collimation axis then not being an axis of revolution.

[0069] The laser radiation which is emitted on the telemetry segment 12, in other words the laser radiation from the remote sensing device 8, propagates through the collimation assembly 20 in the direction of the first orientation mechanism 22.

[0070] The first orientation mechanism 22 is capable of directing the laser radiation emitted on the telemetry segment 12 towards the second orientation mechanism 24.

[0071] The second orientation mechanism 24 is capable of reorienting the laser radiation which is emitted on the telemetry segment 12 along a plurality of directions of the observation plane of the observation system.

[0072] The first orientation mechanism 22 comprises first, second, and third mirrors 26, 28, 30 which are rotatable together. More specifically, the first orientation mechanism 22 includes an orientation member (not shown) capable of simultaneously rotating the first, second, and third mirrors 26, 28, 30 around the collimation axis of the collimation assembly 20 without altering the relative orientation of the first, second, and third mirrors 26, 28, 30 with respect to each other. In other words, the first, second, and third mirrors 26, 28, 30 form a single unit that is independent of the second orientation mechanism 24.

[0073] The first orientation mechanism 22 is here essentially made up of the first, second and third mirrors 26, 28, 30 and the orientation member of the first orientation mechanism 22.

[0074] The first mirror 26 is arranged so as to direct the laser radiation emitted on the telemetry segment 12 and coming from the remote sensing device 8 towards the second mirror 28. More specifically, the main axis of the first mirror 26 forms an angle of 45 degrees with the collimation axis of the collimation assembly 20.

[0075] The second mirror 28 is arranged so as to direct the laser radiation, which is emitted on the telemetry segment 12 and then directed by the first mirror 26, towards the third mirror 30. More specifically, the principal axis of the first mirror 26 is parallel to the principal axis of the second mirror 28.

[0076] The third mirror 30 is arranged so as to direct the laser radiation, which is emitted onto the telemetry segment 12 and then is successively directed by the first mirror 26 and by the second mirror 28, towards the second orientation mechanism 24. More precisely, the main axis of the second mirror 28 forms a 90-degree angle with the main axis of the third mirror 30.

[0077] The second orientation mechanism 24 comprises a movable mirror 32 that rotates about itself, in particular about the collimation axis of the collimation assembly 20, such that the movable mirror 32 includes the collimation axis of the collimation assembly 20. The movable mirror 32 is therefore movable in rotation about an axis parallel to the Y-axis of [Fig. 4]. The movable mirror 32 is capable of directing the laser beam, which is emitted onto the telemetry segment, along the plurality of directions of the observation plane of the observation system.

[0078] Thus, the axis of rotation of the movable mirror 32 is not parallel and not orthogonal to the longitudinal axis of the telemetry segment 12.

[0079] More specifically, the second orientation mechanism 24 includes an orientation member (not shown) capable of driving the movable mirror 32 in rotation around the collimation axis of the collimation assembly 20.

[0080] The second orientation mechanism 24 is here essentially constituted by the movable mirror 32 and the orientation member of the second orientation mechanism 24.

[0081] The first orientation mechanism 22 is mobile in rotation around the second orientation mechanism 24 between a first position and a second position which are here separated from each other by a 90-degree rotation of the first orientation mechanism 22.

[0082] The first orientation mechanism 22 orients, in its first position parallel to the X axis, the laser radiation, which is emitted on the telemetry segment 12 and which comes from the remote sensing device 8, towards the second orientation mechanism 24 according to a first orientation direction.

[0083] The first orientation mechanism 22 orients, in its second position parallel to the Z axis, the laser radiation, which is emitted on the telemetry segment 12 and which comes from the remote sensing device 8, towards the second orientation mechanism 24 according to a second orientation direction.

[0084] A 90-degree angle is formed here between the first and second orientation directions.

[0085] The second orientation mechanism 24, in particular the movable mirror 32, is movable in rotation on itself between a first position and a second position which are here separated from each other by a 90-degree rotation of the second orientation mechanism 24. The movable mirror 32 here comprises two opposite reflective faces.

[0086] The second orientation mechanism 24 reorients, in its first position, the laser radiation, which is emitted onto the telemetry segment 12 and which comes of the first orientation mechanism 22, according to a first direction of the observation plane.

[0087] The second orientation mechanism 24 reorients, in its second position, the laser radiation, which is emitted on the telemetry segment 12 and which comes from the first orientation mechanism 22, according to a second direction of the observation plane.

[0088] With reference to [Fig.6], the first orientation mechanism 22 being in its first position, the second orientation mechanism 24 which is in its first position reorients the laser radiation, which is emitted on the telemetry segment 12 and which comes from the first orientation mechanism 22, according to a direction called "north" of the observation plane of the observation system, that is to say a direction parallel to the Z axis and in the direction of the negative Z.

[0089] With reference to [Fig.7], the first orientation mechanism 22 being in its second position, the second orientation mechanism 24 which is in its first position reorients the laser radiation, which is emitted on the telemetry segment 12 and which comes from the first orientation mechanism 22, in a direction called "south", that is to say parallel to the Z axis and in the direction of the positive Z.

[0090] With reference to [Fig.8], the first orientation mechanism 22 being in its first position, the second orientation mechanism 24 which is in its second position reorients the laser radiation, which is emitted on the telemetry segment 12 and which comes from the first orientation mechanism 22, in a direction called "west", that is to say parallel to the X axis and in the direction of the positive X.

[0091] With reference to [Fig.9], the first orientation mechanism 22 being in its second position, the second orientation mechanism 24 which is in its second position reorients the laser radiation, which is emitted on the telemetry segment 12 and which comes from the first orientation mechanism 22, in a direction said to be "east" of the observation plane of the observation system, that is to say parallel to the X axis and in the direction of the negative X.

[0092] The "north-south" direction is orthogonal to the "east-west" direction.

[0093] When the first orienting mechanism 22 is in its first or second position, and the second orienting mechanism 24 is in its first or second position, the movable mirror 32 is inclined at an angle of 45 degrees with respect to the third mirror 30. More precisely, the principal axis of the movable mirror 32 forms a 45-degree angle with the principal axis of the third mirror 30 in these positions. Regardless of the orientation of the movable mirror 32, the principal axis of the movable mirror 32 is orthogonal to the collimation axis of the collimation assembly 20 and therefore to the axis

[0094] The observation system is thus capable of carrying out telemetry measurements in the north - south - east - west directions of the observation plane of the observation system, the field of observation of the observation system being here 360 ​​degrees horizontally and more than 20 degrees vertically.

[0095] In the described embodiment, the first orientation mechanism 22 can be driven only in its first and second positions, and the second orientation mechanism 24 can be driven only in its first and second positions. Alternatively, the observation system could include a diasporameter equipped with two prisms arranged between the remote sensing device 8 and the orientation device 18, in particular along the path of the laser beam emitted on the telemetry segment 12. In this case, the first and second orientation mechanisms 22, 24 can be continuously driven by angle, and the two prisms of the diasporameter can rotate relative to each other to achieve a fast scanning function, i.e., with a high refresh rate, in a restricted area of ​​the observation plane of the observation system.

Claims

Demands

1. An observation system comprising a laser beam orientation device (18) and a laser remote sensing device (8) configured to perform a range measurement on a range segment (12), characterized in that: - the orientation device (18) is configured to reorient a laser beam emitted on the range segment (12) and direct it in a plurality of directions from an observation plane of the observation system; - the orientation device (18) comprises at least one movable mirror (32) rotating about itself which is configured to direct said laser beam in said plurality of directions; and - an axis of rotation of said movable mirror (32) and a longitudinal axis of said range segment are non-parallel and non-orthogonal.

2. Observation system according to claim 1, wherein: - the orientation device (18) comprises a first orientation mechanism (22) capable of orienting said laser beam, which is emitted on the telemetry segment (12), towards a second orientation mechanism (24) of the orientation device (18); and - the second orientation mechanism (24) is provided with said movable mirror (32) which is capable of reorienting said laser beam, which is emitted on the telemetry segment (12) and then oriented by the first orientation mechanism (22), according to said plurality of directions.

3. Observation system according to claim 2, wherein: - the first orientation mechanism (22) is movable at least between a first position in which the first orientation mechanism (22) orients said laser beam, which is emitted on the telemetry segment (12), towards the second orientation mechanism (24) in a first orientation direction and a second position in which the first orientation mechanism (22) orients said laser beam, which is emitted on the telemetry segment (12), towards the second orientation mechanism (24) in a second orientation direction; and - said movable mirror (32) of the second orientation mechanism (24) is movable in rotation about itself at least between a first position in which said movable mirror (32) reorients said laser beam, which is emitted on the telemetry segment (12) then oriented by the first orientation mechanism (22), along a first direction of the observation plane and a second position in which said movable mirror (32) reorients said laser beam, which is emitted on the telemetry segment (12) then oriented by the first orientation mechanism (22), along a second direction of the observation plane.

4. Observation system according to claim 3, wherein: - when the first orientation mechanism (22) is in its first position, said movable mirror (32) of the second orientation mechanism (24) is capable of reorienting said laser beam, which is emitted on the telemetry segment (12) and then oriented by the first orientation mechanism (22), at least in a direction called "north" of the observation plane of the observation system and in a direction called "south", which is opposite to the north direction;and - when the first orientation mechanism (22) is in its second position, said movable mirror (32) of the second orientation mechanism (24) is capable of reorienting said laser radiation, which is emitted on the telemetry segment (12) and then oriented by the first orientation mechanism (22), at least in a direction called "east" of the observation plane of the observation system and in a direction called "west", which is opposite to the east direction, the "north-south" direction being orthogonal to the "east-west" direction.

5. Observation system according to claim 3 or 4, wherein the first and second orientation directions form an angle of 90 degrees with each other.

6. An observation system according to any one of claims 2 to 5, wherein the first orientation mechanism (22) comprises first, second, and third mirrors (26, 28, 30) which are rotatable together, and wherein: - the first mirror (26) is arranged to direct said laser beam, which is emitted on the telemetry segment (12) of the remote sensing device (8), towards the second mirror (28); - the second mirror (28) is arranged to direct said laser beam, which is emitted on the telemetry segment (12) and then directed by the first mirror (26), towards the third mirror (30); and - the third mirror (30) is arranged to direct said laser beam, which is emitted on the telemetry segment (12) then oriented successively by the first mirror (26) and by the second mirror (28), towards said movable mirror (32) of the second orientation mechanism (24).

7. Observation system according to claim 6, wherein the second mirror (28) is parallel to the first mirror (26), the third mirror (30) being inclined with respect to the second mirror (28), in particular at an angle of 90 degrees.

8. Observation system according to any one of claims 1 to 7, wherein the angle (a) formed between the axis of rotation of said rotating movable mirror (32) and the longitudinal axis of said telemetry segment is 45 degrees.

9. Observation system according to any one of claims 1 to 8, wherein the remote sensing device (8) comprises: - a fixed laser source, a scanning mirror and a remote sensing element configured to perform the range measurement on the range segment (12); or - at least one fixed laser source, in particular a plurality of fixed laser sources which are juxtaposed, and a plurality of remote sensing elements configured to perform the range measurement on the range segment (12).

10. Observation system according to any one of claims 1 to 9, further comprising a diasporameter arranged on the path of said laser beam, which is emitted on the telemetry segment (12), between the orientation device (18) and the remote sensing device (8).

Images