Target pointing device
The target pointing device addresses turbulence and heating issues in high-power laser systems by using a tracking camera with a separate line of sight and a main actuator to adjust the laser's orientation, enabling precise and flexible targeting with multiple lasers.
Patent Information
- Application Number
- FR2023009627
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-09-13
- Publication Date
- 2025-11-21
- Estimated Expiration
- 2043-09-13
AI Technical Summary
Existing high-power laser targeting systems face challenges such as turbulence compensation, optical axis deflection due to heating, limited illumination area, and the need for multiple tracking cameras to achieve precise and sustained targeting.
A target pointing device comprising a high-power laser, a tracking camera with a different line of sight, a main unit for control, and a main actuator to adjust the laser's orientation, optionally with an initialization camera and illumination laser, allowing for precise targeting and sustained energy deposition on a target.
Enables precise targeting with real-time turbulence correction, avoids overheating, eliminates glare issues, and allows simultaneous management of multiple lasers, ensuring accurate and flexible targeting.
Smart Images
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Abstract
Description
Title of the invention: Target pointing device
[0001] The present invention relates to a target pointing device.
[0002] In particular, the targeting is a precise targeting performed by a high-power laser. Specifically, the high-power laser, as well as the associated viewing devices, are generally mounted on a (motorized) structure that allows for pre-targeting. The invention thus relates to the ability to ensure relative tracking between a target and a laser for targeting (precise targeting) with a very high average power laser.
[0003] Conventionally, in the prior art, the support structure for the high-power laser is also the support structure for the tracking camera. The two paths are then mechanically adjusted at the factory relative to each other, and the tracking camera operates in a spectral band different from that of the continuous or quasi-continuous high-power laser. This allows for rejection of the power band to avoid glare.
[0004] Generally, to ensure day and night tracking, the tracking camera is a camera supplemented (especially for nighttime) by a pulsed laser which illuminates the entire target to improve the signal-to-noise ratio.
[0005] The tracking camera is a high-speed camera designed to ensure rapid tracking of the line of sight in order to compensate for atmospheric turbulence, and the area targeted by the laser is the tracking center, or a portion of it close to the tracking center. Thermal effects are not compensated, but the firing time is limited to prevent excessive heating.
[0006] This has several limitations: - The effects due to turbulence are related to the spectral band considered, so if the tracking camera does not work in the spectral band of the laser, we cannot properly correct their effects. - When the high-power laser fires, the temperature rises in the optical carrier structure, and it is extremely difficult to guarantee that the heating will not deflect the laser optical axis from the tracking optical axis. - The illumination zone and the center of pursuit are close since the illuminated area is estimated relative to the center of pursuit. - The illuminated area is only observed through the effects induced on the materials (smoke, flames, temperature rise...) by the tracking camera. - If we want to overlay several tracks, we need as many tracking cameras.
[0007] There is therefore a need for a pointing device that allows energy to be deposited on a precise area of a target during a pursuit ensured by means of a camera, and for a sufficient duration to allow the destruction of the target.
[0008] To this end, the invention relates to a target pointing device comprising:
[0009] - a continuous or quasi-continuous power laser,
[0010] - a pursuit assembly comprising:
[0011] • a tracking camera suitable for acquiring images of the target and the task of the high-power laser on the target, the tracking camera having a different line of sight than the line of sight of the high-power laser,
[0012] • a main unit for generating a control setpoint based on the images acquired by the tracking camera in such a way as to achieve a control of the laser power task on the target, and
[0013] • a main actuator for changing the orientation of the laser line of sight power as a function of the control setpoint.
[0014] According to other advantageous aspects of the invention, the pointing device comprises one or more of the following features, taken individually or in all technically possible combinations:
[0015] - the tracking assembly includes an illumination laser suitable for illuminating the target ;
[0016] - the high-power laser is designed to switch off periodically;
[0017] - the periodic extinctions of the high-power laser are synchronized to the rate illumination laser emission;
[0018] - the tracking camera is an event detection camera;
[0019] - the pursuit camera is a camera having an aperture time allowing the visualization of the high-power laser task without saturation by the high-power laser;
[0020] - the device includes a pursuit initialization assembly comprising:
[0021] - an initialization camera having a common line of sight to the high-power laser, the initialization camera, operating on a different wavelength band than the high-power laser and specifically designed to acquire images of the target,
[0022] - an initialization unit suitable for generating a superposition instruction as a function images acquired by the initialization camera to bring the target into a predetermined position within the initialization camera's field of view so that the line of sight of the high-power laser is positioned on the target,
[0023] the main actuator being suitable for modifying the orientation of the line of sight of the power laser according to the superposition command;
[0024] - the predetermined position is the center of the camera's field of vision initialization;
[0025] - the high-power laser is suitable for performing a scan around the target until this that the signal from the high-power laser be observed on the tracking camera.
[0026] The invention will become clearer upon reading the following description, given solely by way of non-limiting example, and made with reference to the drawings in which:
[0027] [Fig-1] [Fig.1] is a schematic view of a pointing device comprising a high-power laser, as well as a tracking camera independent of the high-power laser's line of sight,
[0028] [Fig.2] [Fig.2] is a schematic view of the field of view of an initialization camera having a common line of sight with that of the power laser, the target being off-center with respect to the line of sight of the initialization camera, and
[0029] [Fig.3] [Fig.3] is another schematic view of the field of view of the initialization camera of [Fig.2], the line of sight of the power laser having been modified so that the target is in the center of the field of view of the initialization camera (laser spot of the power laser brought back on the target).
[0030] A device 10 for pointing at a target C is illustrated by [Fig.1].
[0031] Target C is, for example, a moving target moving in the air, on land, or in sea. Target C is, for example, an aircraft, a drone, a land vehicle or even a naval vessel.
[0032] As illustrated by [Fig.1], the pointing device 10 includes a power laser 12 and a tracking assembly 14. Optionally, the pointing device 10 also includes an initialization assembly 16.
[0033] The pointing device 10 is typically oriented in elevation and azimuth.
[0034] The 12-power laser is a continuous or quasi-continuous laser. The term “quasi” "Continuous" implies that the emission time is greater than or equal to the energy reduction (or absence) time and that the emission times are several hundred milliseconds.
[0035] The power laser 12 has a high average power, typically greater than or equal to 1 kilowatt (kW).
[0036] The 12 power laser typically has a wavelength band between 0.5 micrometers (pm) and 2.5 pm.
[0037] The power laser 12 is supported by a support structure 17 (illustrated in [Fig.1]).
[0038] The tracking assembly 14 is suitable for ensuring the relative tracking of the target C by the power laser 12.
[0039] The tracking assembly 14 includes a tracking camera 30, a main unit 32 for generating a control setpoint and a main actuator 34. Optionally, the tracking assembly 14 also includes an illumination laser 36.
[0040] The tracking camera 30 is suitable for acquiring images of the target C and of the spot of the power laser 12 on the target C (illuminated or not by the illumination laser 36).
[0041] The tracking camera 30 has a line of sight different from the line of sight of the power laser 12. In particular, the tracking camera 30 is positioned outside the support structure 17 of the power laser 12. Since the tracking camera 30 is positioned outside, it is no longer hindered by the backscattering of the power laser 12, nor by the requirement to be at a different wavelength than that of the power laser 12.
[0042] The tracking camera 30 is preferably a camera allowing at least an output rate of certain pixels at more than 5 kHz.
[0043] The tracking camera 30 is suitable for imaging the laser spot 12 on the target C. Several implementation methods, listed below and combinable with each other, are possible for this purpose: - In one implementation example, the tracking camera 30 is a camera with an aperture time that allows visualization of the laser spot 12 without saturation by the laser. The aperture time is therefore short enough to avoid saturation. In one example, telemetry is used to open the tracking camera 30 synchronously with the pulses of the illumination laser 36 backscattered by the target C and the visualization of the laser spot 12 without saturation. • the opening time is, for example, determined by means of a rangefinder present on the structure supporting the carrier camera 30 and which measures the distance of the tracking camera 30 to the target C. - In one implementation example, the tracking camera 30 is an event-based camera designed to detect the emissions of the power laser 12. This allows for limiting latency for tracking and having a high dynamic range so as not to saturate the tracking camera 30. For example, the tracking camera 30 allows for detecting variations in the power laser 12 due to turbulence. In one implementation example, the power laser 12 is designed to periodically switch off (a process known as "blanking") to prevent the tracking camera from becoming overloaded (during the illumination laser's emission). Preferably, the periodic switching off of the power laser 12 is synchronized with the emission rate of the illumination laser 36. A prior measurement of the distance then allows the tracking detector to be opened appropriately. - In one implementation example, the tracking camera 30 is an event-detection camera, and the power laser 12 is designed to switch off periodically (preferably synchronized with the emission rate of the illumination laser 36). Thus, the variations created by the periodic switching off allow for the creation of events and thereby the detection of the task of the power laser 12 over time.
[0044] The main unit 32 is suitable for generating a control command based on the images acquired by the tracking camera 30 so as to achieve control of the task of the power laser 12 on the target C. The main unit 32 is, for example, a computer.
[0045] The main actuator 34 is adapted to modify the orientation of the line of sight of the power laser 12 according to the servo setpoint. The main actuator 34 is typically supported by the support structure 17 and is at the output of the power laser 12. The main actuator 34 comprises, for example, one or more opto-mechanical components.
[0046] The illumination laser 36 is suitable for illuminating the target C.
[0047] The illumination laser 36 is a pulsed laser. The illumination laser 36 and the lasers of power 12 have wavelengths compatible with observation by the tracking camera 30 (i.e. in the wavelength band of the tracking camera 30).
[0048] The optional initialization set 16 is used to initialize the relative tracking of the laser beam 12 onto the target C. In particular, the initialization set 16 is especially useful in the case of small targets, to facilitate the superposition of the laser beam 12 onto the target C at startup. The initialization set 16 is typically carried by the support structure 17.
[0049] The initialization assembly 16 includes an initialization camera 40 and an initialization unit 42.
[0050] The initialization camera 40 operates in a different spectral band than the power laser 12 and is suitable for acquiring images of the target C.
[0051] The initialization camera 40 has a common line of sight to the power laser 12 (factory setting). Thus, the spot formed by the power laser 12 is approximately (taking into account the effects of turbulence) at the center of the field of view of the initialization camera 40. The purpose of using the initialization camera 40 is to bring the target C back to a predetermined position in the field of view of the initialization camera 40 before starting the high-rate servo control of the fine pointing with the tracking assembly 14.
[0052] For example, the line of sight of the initialization camera 40 is brought back to that of the power laser 12 via a hole mirror 46, a splitter or a spectral filter.
[0053] The initialization unit 42 is suitable for generating a superposition command based on the images acquired by the initialization camera 40 to bring the target C into a predetermined position in the field of view of the initialization camera 40 so that the line of sight of the power laser 12 is positioned on the target C. The predetermined position is typically the center or an area close to the center of the field of view of the initialization camera 40. The initialization unit 42 is, for example, a computer.
[0054] The main actuator 34 is suitable for modifying the orientation of the line of sight of the power laser 12 (and where applicable of the initialization camera 40) according to the superposition command.
[0055] Alternatively, the pointing device 10 does not include an initialization set 16 and the positioning of the power laser 12 spot on the target C is done at start-up via a scan performed by the power laser 12 around the target C until the signal is observed on the tracking camera 30. For example, the site-bearing orientation of the device 10 can be used to perform the scanning pattern.
[0056] An example of the operation of the pointing device 10 will now be described.
[0057] When the device 10 includes an initialization set 16, the target C, optionally illuminated by the illumination laser 36, is imaged by the initialization camera 40. The initialization unit 42 generates a superposition command sent to the main actuator 34 aimed at bringing the target C back to the center of the field of view of the initialization camera 40 so that the line of sight of the power laser 12 is positioned on the target C.
[0058] By way of example, Figures 2 and 3 illustrate the field of view of the initialization camera 40, with the power laser 12 emitted at the center of the field of view (common line of sight with the initialization camera 40). The transition from [Fig. 2] to [Fig. 3] is achieved by changing the orientation of the line of sight of the power laser 12 (and therefore of the initialization camera 40), thus bringing the target C back to the center of the field of view of the initialization camera 40.
[0059] Alternatively, the power laser 12 performs a scan around the target C until the signal from the power laser 12 is observed on the tracking camera 30.
[0060] Once the spot of the high-power laser 12 is visible on the target C by the tracking camera 30, images of the target C and the spot of the high-power laser 12 are successively acquired by the tracking camera 30. The main unit 32 generates a control command, sent to the main actuator 34, aimed at achieving a control of the task of the power laser 12 on the target C (so that the task of the power laser 12 remains concentrated in the same place).
[0061] Thus, the pointing device 10 described allows the replacement of a monostatic system comprising a tracking camera 30 and a continuous or quasi-continuous laser of factory-set power by a bistatic system composed of these two elements, the absence of adjustment between the two being compensated by specific energy management and / or the use of particular detectors.
[0062] Such a pointing device 10 allows for much greater flexibility (orientation of the line of sight, multiple beams, etc.) and better pointing correction (correction by viewing the high-power laser 12). Thus, it eliminates the problems of overheating in the structure supporting the high-power laser 12, camera glare issues related to the monostatic system, and provides better tilt correction due to turbulence.
[0063] In summary, the pointing device 10 has many advantages: - As we see the power laser 12 on the tracking camera 30, it is possible to correct the effects related to turbulence with a measurement at the same wavelength as the power laser. - If the structure moves in temperature, the direction of the 12 power laser will be corrected in real time and will therefore always illuminate the same targeted point. - It is possible to directly address any location on target C, including the most vulnerable areas. - The illuminated area is observed directly and it is possible to see directly the effects of the laser on target C. - It is possible to manage several lasers simultaneously at the same wavelength or at similar wavelengths. - We eliminate the glare problems of monostatic solutions
[0064] The person skilled in the art will understand that the embodiments described can be combined with each other provided that they are technically compatible.
Claims
Demands
1. A device (10) for pointing at a target (C) comprising: - a high-power laser (12) with continuous or quasi-continuous power, - a pursuit set (14) comprising: • a tracking camera (30) suitable for acquiring images of the target (C) and of the spot of the power laser (12) on the target (C), the tracking camera (30) having a line of sight different from the line of sight of the power laser (12), • a main unit (32) for generating a control setpoint based on the images acquired by the tracking camera (30) so as to achieve control of the task of the high-power laser (12) on the target (C), and • a main actuator (34) capable of modifying the orientation of the line of sight of the high-power laser (12) according to the control setpoint, the device further comprising an initialization set (16) of the pursuit comprising: - an initialization camera (40) having a common line of sight to the power laser (12), the initialization camera (40) operating on a different wavelength band than the power laser (12) and being suitable for acquiring images of the target (C), - an initialization unit (42) capable of generating a superposition command based on the images acquired by the initialization camera (40) to bring the target (C) into a predetermined position in the field of view of the initialization camera (40) so that the line of sight of the power laser (12) is positioned on the target (C), the main actuator (34) being suitable for modifying the orientation of the line of sight of the power laser (12) according to the superposition command.
2. Device according to claim 1, wherein the tracking assembly (14) includes an illumination laser (36) adapted to illuminate the target (C).
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7. Device according to claim 1 or 2, wherein the power laser (12) is adapted to turn off periodically. Device according to claims 2 and 3, wherein the periodic extinctions of the power laser (12) are synchronized with the emission rate of the illumination laser (36). Device according to any one of claims 1 to 4, wherein the tracking camera (30) is an event-detecting camera. Device according to any one of claims 1 to 4, wherein the tracking camera (30) is a camera having an opening time enabling visualization of the task of the power laser (12) without saturation by the power laser (12). Device according to any one of claims 1 to 6, wherein the predetermined position is the center of the field of view of the initialization camera (40).