Target pointing device
The target pointing device uses a high-power laser and pulsed beacon laser with a separate tracking camera to address turbulence and heating issues, enabling precise and efficient energy deposition on targets.
Patent Information
- Application Number
- FR2023009626
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-09-13
- Publication Date
- 2026-01-09
- Estimated Expiration
- 2043-09-13
AI Technical Summary
Existing high-power laser targeting systems face challenges such as turbulence compensation, heating issues, glare interference, and the need for multiple tracking cameras to ensure precise targeting and prolonged energy deposition on a target.
A target pointing device with a high-power laser and a pulsed beacon laser sharing a common line of sight, combined with a tracking camera operating at a different wavelength, and a control system to activate the high-power laser only after precise targeting is achieved, allowing for precise and prolonged energy deposition.
Enables precise targeting with real-time turbulence correction, avoids heating and glare issues, and allows simultaneous management of multiple lasers, ensuring effective energy deposition on target areas.
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 set of lasers comprising:
[0010] • a continuous or quasi-continuous power laser,
[0011] • a pulsed beacon laser,
[0012] the high-power laser and the beacon laser having a common line of sight,
[0013] - a pursuit assembly comprising:
[0014] • a tracking camera suitable for acquiring images of the target and the task of the laser beacon on the target, the tracking camera having a different line of sight from the line of sight of the power laser and the beacon laser,
[0015] • 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 beacon's task on the target, and
[0016] • a main actuator for changing the orientation of the laser line of sight power and laser beacon depending on the servo control setpoint,
[0017] the power laser being activated only when the task of the beacon laser being controlled on the target is achieved.
[0018] 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:
[0019] - the tracking assembly includes a laser for illuminating the target ;
[0020] - the tracking camera includes a spectral filter centered on a band of wavelengths different from that of the high-power laser;
[0021] - the spectral filter of the tracking camera is centered on the length band laser beacon wave;
[0022] - the high-power laser is designed to switch off periodically during the period laser beacon emission;
[0023] - the beacon laser and the illumination laser have the same emission rate and are syn chronicled;
[0024] - the pursuit camera is a camera having an aperture time allowing the vi sualisation of the beacon laser task without saturation by the power laser;
[0025] - the tracking camera is an event-detection camera designed to detect the emissions from the laser beacon;
[0026] - the device includes a pursuit initialization set comprising:
[0027] - an initialization camera having a common line of sight to the high-power laser and with the beacon laser, the initialization camera operates on a different wavelength band than the power laser and is specifically designed to acquire images of the target, and
[0028] - 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 beacon laser is positioned on the target,
[0029] the main actuator being suitable for modifying the orientation of the line of sight of the power laser according to the superposition command;
[0030] - the beacon laser is suitable for performing a scan around the target until the The signal from the laser beacon should be observed on the tracking camera.
[0031] 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:
[0032] [Fig-1] [Fig.1] is a schematic view of a pointing device comprising a a high-power laser, a beacon laser having a common line of sight with the high-power laser, and a tracking camera independent of the line of sight of the high-power laser and the beacon laser,
[0033] [Fig.2] [Fig.2] is a schematic view of the field of view of a camera initialization camera having a common line of sight with that of the power laser and the beacon laser, the target being off-center with respect to the line of sight of the initialization camera, and
[0034] [Fig.3] [Fig.3] is another schematic view of the camera's field of view of initialization of [Fig.2], the line of sight of the power laser and the beacon 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 beacon laser brought back on the target).
[0035] A device 10 for pointing at a target C is illustrated by [Fig.1].
[0036] 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.
[0037] As illustrated by [Fig.1], the pointing device 10 includes a set of lasers 12 and a tracking set 14. Optionally, the pointing device 10 also includes an initialization set 16.
[0038] The pointing device 10 is typically oriented in elevation and azimuth.
[0039] The laser set 12 includes a power laser 20 and a beacon laser 22.
[0040] The 20-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 time of reduction (or absence) of energy and that emission times are several hundred milliseconds.
[0041] The power laser 20 is only activated when the task of the beacon laser 22 is controlled on the target C.
[0042] The power laser 20 has a high average power, typically greater than or equal to 1 kilowatt (kW).
[0043] The 20 power laser typically has a wavelength band between 0.5 micrometers (pm) and 2.5 pm.
[0044] The beacon laser 22 is a pulsed laser. The pulse rate of the beacon laser 22 is high, typically a few kilohertz (kHz).
[0045] The beacon laser 22 has a high peak power, but an average power much lower than the average power of the power laser 20, its purpose being to visualize the point of impact of the power laser (superimposed on the beacon laser), in order to ensure relative tracking between the target C and the beacon laser while ensuring eye safety at the level of the target C. Typically, the average power of the beacon laser 22 is less than or equal to a few W (e.g. 10 Watts).
[0046] The beacon laser 22 preferably has a wavelength band identical or close to that of the power laser 20. By "close," it is understood that the wavelength difference is less than or equal to typically 0.2 pm. For example, the power laser 20 is at 1 pm and the beacon laser 22 is at 0.9 pm.
[0047] The power laser 20 and the beacon laser 22 have a common line of sight. For example, the beacon laser 22 can be injected into the fiber of the power laser 20 or combined with the power laser 20 by means of a grating-type optical component. For example, the power laser 20 and the beacon laser 22 are carried by the same carrier structure 17.
[0048] The tracking assembly 14 is suitable for ensuring the relative tracking of the target C by the beacon laser 22 (and therefore the power laser 20).
[0049] 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.
[0050] The tracking camera 30 is suitable for acquiring images of the target C and of the spot of the beacon laser 22 on the target C (illuminated or not by the illumination laser 36).
[0051] The tracking camera 30 has a different line of sight from the line of sight of the high-power laser 20 and the beacon laser 22. In particular, the tracking camera 30 is positioned outside the support structure 17 of the high-power laser 20 and the beacon laser 22. Since the tracking camera 30 is positioned outside, it is no longer hindered by backscattering from the high-power laser 20, nor by the requirement to be at a distance a different wavelength than that of the 20 power laser.
[0052] The tracking camera 30 is preferably a camera allowing at least an output rate of certain pixels at more than 5 kHz.
[0053] The tracking camera 30 is designed to image the task of the beacon laser 22 on the target C. Several implementation methods, listed below and combinable with each other, are possible for this purpose: - In one example implementation, the tracking camera 30 includes a spectral filter centered on a spectral band of the camera different from that of the power laser 20. This allows the tracking camera 30 not to be dazzled by the power laser 20. Preferably, the spectral filter of the tracking camera 30 is centered on the spectral band of the beacon laser 22 (for example, beacon laser 22 and spectral filter at 0.9 pm, and power laser 20 at 1 pm). - In one implementation example, the power laser 20 is designed to switch off periodically during the emission period of the beacon laser 22. This prevents the tracking camera 30 from becoming overloaded. This phenomenon is called "blanking." The extinction duration is, for example, a few tens of nanoseconds. In one implementation example, the tracking camera 30 is a camera with an aperture time that allows visualization of the beacon laser 22's spot without saturation by the high-power laser 20. 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 beacon laser 22's spot without saturation. The aperture time is, for example, determined by means of a rangefinder located on the structure supporting the camera 30, which measures the distance from the tracking camera 30 to the target C. - In one implementation example, the tracking camera 30 is an event-based camera designed to detect emissions from the beacon laser 22. This allows for limiting latency for tracking and providing a high dynamic range to avoid saturating the tracking camera 30.
[0054] 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 beacon laser 22 on the chosen area of the target C. The main unit 32 is, for example, a computer.
[0055] The main actuator 34 is adapted to modify the orientation of the line of sight of the The power laser 20 and the beacon laser 22 operate according to the control setpoint. The main actuator 34 is typically supported by the support structure 17 and is at the output of the power laser 20. The main actuator 34 includes, for example, one or more opto-mechanical components.
[0056] The illumination laser 36 is suitable for illuminating the target C.
[0057] The illumination laser 36 is a pulsed laser. The illumination laser 36 and the laser beacon 22 have wavelengths compatible with observation by tracking camera 30 (i.e. in the wavelength band of tracking camera 30).
[0058] The optional initialization set 16 is used to initialize the relative tracking of the beacon laser 22's task on the target C. In particular, the initialization set 16 is especially useful in the case of small targets, to facilitate the superposition of the beacon laser 22's task on the target C at startup. The initialization set 16 is typically carried by the support structure 17.
[0059] The initialization assembly 16 includes an initialization camera 40, an initialization unit 42.
[0060] The initialization camera 40 operates in a different spectral band than the power laser 20 and is suitable for acquiring images of the target C.
[0061] The initialization camera 40 has a common line of sight for the power laser 20 and the beacon laser 22 (factory setting). Thus, the spot formed by the beacon laser 22 (and also by the power laser 20) 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-speed servo control of the fine pointing.
[0062] For example, the line of sight of the initialization camera 40 is brought back to that of the power laser 20 and the beacon laser 22 via a hole mirror 46, a splitter or a spectral filter.
[0063] 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 beacon laser 22 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.
[0064] The main actuator 34 is suitable for modifying the orientation of the line of sight of the power laser 20 and the beacon laser 22 (and where applicable the initialization camera 40) according to the superposition instruction.
[0065] Alternatively, the pointing device 10 does not include an initialization set 16 and the positioning of the beacon laser 22 task on the target C is done at start-up via a scan carried out by the beacon laser 22 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 carry out the scanning pattern.
[0066] An example of the operation of the pointing device 10 will now be described.
[0067] At startup, only the beacon laser 22 is activated and the power laser 20 is off.
[0068] 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 beacon laser 22 is positioned on the target C.
[0069] By way of example, Figures 2 and 3 illustrate the field of view of the initialization camera 40, with the beacon laser 22 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 beacon laser 22 (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.
[0070] Alternatively, the beacon laser 22 performs a scan around the target C until the signal from the beacon laser 22 on the target C is observed on the tracking camera 30.
[0071] Once the spot of the beacon laser 22 is visible on the target C by the tracking camera 30, images of the target C and of the spot of the beacon laser 22 are successively acquired by the tracking camera 30. The main unit 32 generates a servo command, sent to the main actuator 34, aimed at achieving servo control of the spot of the beacon laser 22 on the target C (so that the spot of the beacon laser 22 remains concentrated in the same place).
[0072] The power laser 20 is then activated once the task of the beacon laser 22 is controlled on the target C.
[0073] Thus, the pointing device 10 described allows the replacement of a monostatic system comprising a tracking camera 30 and a continuous or quasi-continuous power laser factory set by a bistatic system between these two elements, the absence of setting between the two being compensated by the knowledge of the line of sight position of the power laser 20 via the visualization of a beacon laser 22 collinear and superimposed with this power laser 20.
[0074] The position of the beacon laser 22 seen on the target C by the tracking camera 30 allows the beacon laser task 22 to be controlled on the target C, then the activation of the power laser 20 allows the effect to be applied to the target C. This relative tracking of the target C and the laser task makes it possible to avoid monostaticity and precise harmonization between the camera and the laser.
[0075] 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 seeing the beacon laser 22). Thus, it eliminates the problems of heating in the structure carrying the high-power laser 20, the glare problems of the camera related to the monostatic system, and provides better tilt correction due to turbulence.
[0076] In summary, the pointing device 10 has many advantages: - The use of a beacon laser 22 to perform the servoing allows the power laser 20 to be switched on only once the servoing has been performed, in complete eye safety. - As we see the beacon laser 22 on the tracking camera 30, it is possible to correct the effects related to turbulence, in particular with a measurement at the same wavelength or close to that of the power laser. - If the structure moves in temperature, the direction of the beacon laser 22 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.
[0077] A 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 target (C) pointing device (10) comprising: - a laser set (12) including: • a continuous or quasi-continuous power laser (20), • a pulsed beacon laser (22), the power laser (20) and the beacon laser (22) having a common line of sight, - a tracking set (14) including: • a tracking camera (30) adapted to acquire images of the target (C) and of the spot of the beacon laser (22) on the target (C), the tracking camera (30) having a line of sight different from the line of sight of the power laser (20) and the beacon laser (22), • 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 spot of the beacon laser (22) on the target (C),and • a main actuator (34) capable of modifying the orientation of the line of sight of the power laser (20) and the beacon laser (22) according to the control setpoint, the power laser (20) being activated only when the control of the beacon laser (22) task on the target (C) is achieved.
2. Device (10) according to claim 1, wherein the tracking assembly (14) includes an illumination laser (36) adapted to illuminate the target (C).
3. Device (10) according to claim 1 or 2, wherein the tracking camera (30) comprises a spectral filter centered on a band of wavelengths different from that of the power laser (20).
4. Device (10) according to claim 3, wherein the spectral filter of the tracking camera (30) is centered on the wavelength band of the beacon laser (22).
5. Device (10) according to any one of claims 1 to 4, wherein the power laser (20) is adapted to switch off periodically during the emission period of the beacon laser (22).
6. Device (10) according to claim 2 optionally combined with any one of claims 3 to 5, wherein the beacon laser (22) and the illumination laser (36) have the same emission rate and are synchronized.
7. Device (10) according to any one of claims 1 to 6, wherein the tracking camera (30) is a camera having an aperture time enabling visualization of the beacon laser task (22) without saturation by the power laser (20).
8. Device (10) according to any one of claims 1 to 6, wherein the tracking camera (30) is an event-detecting camera adapted to detect emissions from the beacon laser (22).
9. Device (10) according to any one of claims 1 to 8, wherein the device (10) comprises a tracking initialization assembly (16) including: - an initialization camera (40) having a line of sight common to the power laser (20) and the beacon laser (22), the initialization camera (40) operating on a wavelength band different from that of the power laser (20) and being adapted to acquire images of the target (C), and - an initialization unit (42) adapted to generate 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) such that the line of sight of the beacon laser (22) is positioned on the target (C),the main actuator (34) being adapted to modify the orientation of the line of sight of the high-power laser (12) according to the superposition command.
10. Device according to any one of claims 1 to 8, wherein the beacon laser (22) is adapted to perform a scan around the target (C) until the signal from the beacon laser (22) is observed on the tracking camera (30).