Celestial body star point simulation method and device based on light field regulation and control

Abstract

The invention relates to a celestial body star point simulation method and device based on light field regulation and control, and provides a method for realizing large-range and high-moving-precision single or multiple star point precise regulation and control by utilizing a composite modulation effect of light field regulation and control on light information for the first time. Multi-star-point large-view-angle movement is simulated through a large-range regulation and control module composed of a laser light source, a light field regulation and control device and a spatial frequency expansion device, star-point high-precision movement is simulated through a micro-angle regulation and control device, and parallel light output with a large deflection angle range and high-precision deflection is generated through an aperture matching output device. A cross-scale multi-star-point simulation technology is applied to calibration of ultra-high-precision celestial body measurement sensors at the millisecond-arc level and the sub-second-arc level. Compared with the prior art, the problem that the light beam angle deflection range and precision are seriously limited in the current celestial body star point simulation technology is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of light field control, and in particular to a method and device for simulating celestial body star points based on light field control. Background Art

[0002] As a high-precision attitude test element, star sensors are one of the core components of spacecraft. They monitor the attitude information of spacecraft such as satellites by observing the angular distance of celestial star points. The accurate measurement of the attitude information of spacecraft by star sensors will directly affect the attitude accuracy of spacecraft on orbit, so the calibration accuracy of star sensors must be improved. At present, due to the technical complexity and high cost of on-orbit calibration, researchers mainly use star point simulators in ground laboratories to detect and calibrate sensors. However, with the rapid development of sensors, traditional star point simulation methods based on collimators are difficult to provide the required star point simulation range and accuracy for milliarcsecond and sub-milliarcsecond precision star sensors. In addition, multi-star point dynamic simulation often relies on complex mechanical scanning, and the system aberrations and environmental disturbances of complex optical components are difficult to actively compensate. Therefore, it is urgent to carry out cross-scale and extremely high-precision celestial star point simulation methods and devices to meet the needs of extremely high-precision astrometric star sensor experiments.

[0003] Light field manipulation can convert the Gaussian beam emitted by the laser into a customized spatial light field by modulating the amplitude, phase, polarization state and other information of the light field. As a core technology, it has been widely used in laser processing, optical communication, microscopic imaging, optical micromanipulation, lidar and other fields. For example, in the field of laser processing, light field manipulation can modulate picosecond pulse light to generate many structured beams such as flat-top beams and vortex beams, which helps to reduce ablation errors, increase processing speed and energy material coupling efficiency, etc.; in the field of optical communications, light field manipulation can construct vortex beams carrying optical orbital angular momentum, which has become a very promising method for expanding communication capacity. At the same time, it can also calibrate and compensate for phase shifts caused by disturbances such as atmospheric turbulence; in the field of microscopic imaging, light field manipulation can shape high-precision and rapidly switchable stripe light and structured light, and can also provide high precision for interferometry. Precise, fast and stable phase shift has greatly promoted the development of super-resolution microscopy; in the field of optical micromanipulation, light field manipulation can form tiny optical energy potential wells, creating optical tweezers that capture and move tiny particles; in the field of holographic display, light field manipulation can create large-viewing-angle and high-resolution holographic projections; in the field of lidar, light field manipulation can replace microwave phased array antennas, and by controlling the phase of each coherently synthesized unit light beam, it can precisely control the direction of light beam emission and achieve high-precision optical scanning without mechanical inertia. It can also emit multiple light beams at the same time to track moving targets in real time.

[0004] Compared with star point simulation methods such as parallel light pipes, light field control has unique advantages. First, the spatial light modulator has the function of dynamic refresh, supports dynamic scanning of parallel light, and the movement of a single star point does not require mechanical movement and rotation of the device; second, it can simultaneously shape multiple parallel lights by calculating and controlling the superposition amplitude and phase of multiple plane waves, supporting the occurrence of multiple star points (supporting different intensities) rather than single star points. Third, the flickering, frame loss, beat frequency and other problems caused by the sampling frequency and integration time of the detector during target acquisition no longer occur under the method of using light field control for target simulation. Fourth, light field control can compensate for the phase and amplitude of the simulated parallel light superposition, actively calibrate the distortion and aberration of the system and the environment, reduce the design difficulty of optical lenses, etc., reduce the burden of system maintenance and recalibration, and ensure the high resolution and stability of the simulated star points. Fifth, light field control can change the deflection angle of parallel light by changing the phase of the light field. Due to the deep adjustable phase depth and high resolution, it can achieve high-subdivision and large-range parallel light deflection, and realize the simulation of large viewing angles and high-precision star points. Sixth, light field control is applicable to a wide spectrum from infrared to visible light, and has the potential to simulate infinitely far away starlight with different spectral characteristics. Therefore, using the principles and technologies of light field control to conduct research on cross-scale and extremely high-precision celestial star point simulation methods has important scientific significance and application value. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a method and device for simulating celestial star points based on light field control, which uses light field control technology to deflect plane waves over a large range and with high precision, thereby simulating large dynamic range scanning and small angle movement of a single or several celestial star points.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A method for simulating celestial star points based on light field control comprises the following steps:

[0008] Generate a laser light source, and collimate and expand the laser light source to generate a collimated light beam;

[0009] Modulate the wavefront information of the light field of the collimated light beam to obtain an outgoing controlled light field;

[0010] Perform spatial frequency expansion on the outgoing regulated light field to obtain a single or several simulated star points with a larger range of field of view expansion;

[0011] The simulated star points are controlled at micro-angles to generate cross-scale star point simulation targets that can be precisely moved at an angle within the expanded viewing angle range.

[0012] The effective aperture of the cross-scale star point simulation target is adjusted and matched to obtain a single or several target parallel lights for star sensor calibration.

[0013] Furthermore, a light field control device is used to modulate the light field wavefront information of the collimated light beam, and the light field control device performs modulation by a super-pixel control method based on a digital micromirror array, a Lee-type computational holographic method based on a digital micromirror array, or a binary encoding method based on a digital micromirror array;

[0014] The super-pixel control method based on digital micromirror array is specifically as follows:

[0015] The collimated light beam incident into the light field control device is irradiated on the digital micromirror array, and each p of the digital micromirror array is x ×p y Adjacent micromirrors form a super-pixel, and the complex amplitude wavefront of the corresponding point in the collimated light beam is regulated by binary intensity control of turning on and off the micromirrors contained in the super-pixel; the diffracted light on the diffraction order regulated by the super-pixel is selected by the optical system to generate the output regulated light field;

[0016] The Lee-type computer-generated holographic method based on digital micromirror array is specifically as follows:

[0017] The collimated light beam incident into the light field control device is irradiated on the digital micromirror array, and the stripe grating is loaded by the digital micromirror array for control, the phase information of the collimated light beam is encoded as the stripe position of the grating, and the amplitude information is encoded as the stripe peak and valley value of the grating, and the regulated diffracted light is selected by the optical system to generate the output controlled light field;

[0018] The binary encoding method based on digital micromirror array is specifically as follows:

[0019] The collimated light beam incident into the light field control device is irradiated on the digital micromirror array, and the digital micromirror array is used to perform binary intensity control of on and off. The regulated diffracted light is selected through the optical system to generate the output controlled light field.

[0020] Furthermore, a light field control device is used to modulate the light field wavefront information of the collimated light beam, and the light field control device generates an output control light field with specific information in the required wavefront based on a liquid crystal spatial light modulator.

[0021] Furthermore, a light field control device is used to modulate the light field wavefront information of the collimated light beam, a single simulated star point corresponds to one control information in the light field control device, and a plurality of simulated star points correspond to a plurality of control information in the light field control device, and a movable single or multiple simulated star points are generated by switching the control information in the light field control device;

[0022] A single simulated star point corresponds to a control wavefront in the light field control device, and a plurality of simulated star points correspond to a superimposed control wavefront in the light field control device. The plurality of simulated star points are generated by controlling the superimposed control wavefront in the light field control device.

[0023] Furthermore, a spatial frequency expansion device is used to expand the spatial frequency of the output control light field. The processing process of the spatial frequency expansion device is specifically as follows:

[0024] The laser light source is expanded into a plurality of laser beams with different emission angles in a two-dimensional plane distributed manner, and a laser beam is selected from the laser beams to obtain a plurality of emission control light fields with different emission angles through modulation of the light field wavefront information, so as to expand the star point simulation range and irradiate the scattering medium; the scattering medium expands the propagation trajectory of the photons of the emission control light field, and further expands the control spatial frequency; the photons are scattered by the scattering medium and converged to generate a single or several simulated star points with a larger range of field of view expansion.

[0025] Furthermore, the light field control device modulates the light field wavefront information of the collimated light beam to obtain an outgoing controlled light field; and performs spatial frequency expansion on the outgoing controlled light field to obtain a single or multiple simulated star points in a larger range of the field of view expansion, specifically:

[0026] The collimated light beam is gated and regulated at the pixel level by the digital micromirror array splicing system, and becomes a point light source that only emits from the gated pixel; the point light source is collimated and aberration corrected, and then converged into a simulated star point by the optical system;

[0027] The digital micromirror array splicing system is composed of multiple digital micromirror arrays spliced ​​in a two-dimensional plane matrix;

[0028] By gating and regulating different pixels of the digital micromirror array splicing system, simulated star points with an extended field of view are generated.

[0029] Furthermore, a micro-angle light field control device is used to control the simulated star point at a micro-angle. The micro-angle light field control device deflects the simulated star point at an angle by rotating a wedge prism or a deflecting reflector to generate a cross-scale star point simulation target. The specific process is as follows:

[0030] The simulated star point is collimated to become a parallel light beam, which is incident on a wedge-shaped prism or a reflector; by rotating the wedge-shaped prism or the deflection reflector, the parallel light beam is deflected at an angle to generate a cross-scale star point simulation target.

[0031] Furthermore, an aperture matching output device is used to adjust the effective aperture of the cross-scale star point simulation target, the aperture matching output device includes an aperture adjustment optical element, and the processing process of the aperture matching output device is specifically as follows:

[0032] The cross-scale star point simulation target is incident on the aperture adjustment optical element to obtain collimated parallel light with an aperture matching the star sensor, and based on the focal length ratio of the aperture adjustment optical element, the movement angle of the collimated parallel light is further reduced to obtain a single or multiple target parallel lights for star sensor calibration.

[0033] The present invention also provides a celestial body star point simulation device for realizing the celestial body star point simulation method based on light field control as described above, comprising a laser light source, a collimating beam expansion device, a light field control device, a spatial frequency expansion device, a micro-angle light field control device, an aperture matching output device and a main control computer;

[0034] The light emitted by the laser light source generates a collimated light beam after passing through the collimating beam expansion device; the collimated light beam is input into the light field control device at a specific incident angle, and is controlled by the light field control device to become an outgoing control light field with controllable wavefront; the outgoing control light field passes through the spatial frequency expansion device to generate a single or multiple simulated star points in a larger range; the simulated star points then pass through the micro-angle light field control device to generate cross-scale star point simulation targets that can move at precise angles within the expanded viewing angle range; the cross-scale star point simulation targets pass through the aperture matching output device to obtain a single or multiple target parallel lights required for star sensor calibration; the main control computer is used to synchronously control the control information of the light field control device, the spatial frequency expansion device and the micro-angle light field control device.

[0035] Furthermore, the laser light source is a monochromatic light source or a broadband light source;

[0036] The light emitted by the monochromatic light source passes through the collimating and beam expanding device, and then irradiates the light field regulating device at a specific incident angle, and is regulated to become the output regulated light field;

[0037] The light emitted by the broadband light source is collimated and expanded by the collimating and expanding device to generate a broadband light beam, which irradiates the light field regulating device and is regulated to become the output regulated light field.

[0038] Compared with the prior art, the present invention has the following advantages:

[0039] (1) The present invention combines light field control technology with the star sensor calibration requirements for the first time, and realizes cross-scale extremely high-precision star point simulation through active light field control, which can support star point simulation with a large moving range and high moving precision.

[0040] (2) The present invention uses a spatial frequency expansion device to expand the spatial frequency of the light field, so that more spatial high-frequency information can be expanded during the propagation of the regulated light field, thereby increasing the simulation range of the star point.

[0041] (3) The present invention effectively realizes the precise movement of star points through a micro-angle light field control device, greatly improving the movement accuracy of star point simulation.

[0042] (4) The present invention can actively generate simulations of non-single star points and dynamic movement simulations of star points through light field control technology without mechanical scanning;

[0043] It can also actively compensate for system or environmental aberrations, significantly improving accuracy and anti-disturbance compared to traditional technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic structural diagram of a celestial star point simulation device based on light field control provided in Example 1 of the present invention;

[0045] Figure 2 This is a schematic diagram of the working process of a celestial star point simulation device based on light field control provided in Example 1 of the present invention;

[0046] Figure 3 This is a schematic structural diagram of a celestial star point simulation device based on light field control provided in Example 2 of the present invention;

[0047] Figure 4 This is a schematic diagram of the working process of a celestial star point simulation device based on light field control provided in Example 2 of the present invention;

[0048] Figure 5 A schematic diagram of the analytical principle of a celestial star point simulation scattering medium provided in Example 2 of the present invention;

[0049] Figure 6 This is a schematic structural diagram of a celestial star point simulation device with extremely high precision across scales based on light field regulation sub-aperture splicing provided in Example 3 of the present invention;

[0050] Figure 7 A schematic diagram of the structure of a digital micromirror array splicing system provided in Example 3 of the present invention;

[0051] In the figure, 1, laser light source, 2, collimation and beam expansion device, 201, first collimator, 3, light field control device, 301, digital micromirror array, 302, focusing mirror, 311, digital micromirror array splicing system, 3111, closed pixel-level micromirror, 3112, opened pixel-level micromirror, 312, fourth collimator, 313, deformable mirror, 314, focusing mirror, 315, fifth collimator, 4, spatial frequency expansion device, 401, optical fiber splitter beam dispensing device, 402, scattering medium, 403, second collimating mirror, 5, micro-angle light field control device, 501, wedge prism, 502, first rotating table, 503, second rotating table, 511, reflecting mirror, 512, deflecting table, 6, aperture matching output device, 601, focusing mirror, 602, third collimating mirror, 7, astronomical measurement sensor, 8, main control computer, 9, spectroscopic plate, 10, parallel light tube, 11, photoelectric detector, 12, interferometer. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0053] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0055] In the description of the present invention, it should be noted that the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0056] Example 1

[0057] This embodiment provides a method for simulating celestial star points based on light field control, comprising the following steps:

[0058] S1: Generate a laser light source 1, and collimate and expand the laser light source 1 to generate a collimated light beam;

[0059] S2: modulate the wavefront information of the collimated light beam to obtain an output controlled light field;

[0060] S3: perform spatial frequency expansion on the outgoing regulated light field to obtain a single or several simulated star points in a larger range with an expanded field of view;

[0061] S4: Perform micro-angle light field control on the simulated star points to generate cross-scale star point simulation targets with large moving range and high moving accuracy;

[0062] S5: Adjust and match the effective aperture of the cross-scale star point simulation target to obtain a single or several target parallel lights for star sensor calibration.

[0063] Specifically, in step S2, the light field control device 3 is used to modulate the light field wavefront information of the collimated light beam, and the light field control device 3 performs modulation by a super-pixel control method based on a digital micromirror array, a Lee-type computational holographic method based on a digital micromirror array, or a binary encoding method based on a digital micromirror array;

[0064] 1 The super-pixel control method based on digital micromirror array is as follows:

[0065] The collimated light beam incident into the light field control device 3 is irradiated on the digital micromirror array, and each p of the digital micromirror array is x ×p y Adjacent micromirrors form a superpixel, and the complex amplitude wavefront of the corresponding point in the collimated light beam is regulated by binary intensity control of the micromirrors contained in the superpixel by turning on and off. The complex amplitude wavefront value of each point in the light field is then regulated by controlling each superpixel on the digital micromirror array, and the control of the complex amplitude wavefront value of each point includes the simultaneous control of the amplitude and phase. The diffracted light on the diffraction order regulated by the superpixel is selected by the optical system to generate an output regulated light field.

[0066] 2 The Lee-type computational holographic method based on digital micromirror array is as follows:

[0067] The collimated light beam incident into the light field control device 3 is irradiated on the digital micromirror array, and the stripe grating is loaded by the digital micromirror array for control. The phase information of the collimated light beam is encoded as the stripe position of the grating, and the amplitude information is encoded as the stripe peak and valley value of the grating. The regulated diffracted light is selected by the optical system to generate an outgoing controlled light field.

[0068] 3 The binary encoding method based on digital micromirror array is specifically as follows:

[0069] The collimated light beam incident into the light field control device 3 is irradiated on the digital micromirror array, and the digital micromirror array performs binary intensity control of on and off. The regulated diffracted light is selected through the optical system to generate an output controlled light field.

[0070] Optionally, the digital micromirror array may be replaced with a liquid crystal spatial light modulator, and the light field control device 3 based on the liquid crystal spatial light modulator may generate the required output control light field with specific information on the wavefront.

[0071] Preferably, the mobility of a single or several simulated star points is achieved by high-speed switching of the control information of the light field control device 3: a single simulated star point corresponds to one control information in the light field control device 3, and multiple simulated star points correspond to multiple control information in the light field control device 3. The movement of the simulated star point also corresponds to multiple control information. By high-speed switching of the control information in the light field control device 3, a movable single or several simulated star points are generated;

[0072] Preferably, a plurality of simulated star points are realized by superimposing wavefront information by regulating the light field regulating device 3:

[0073] A single simulated star point corresponds to a control wavefront in the light field control device 3, and multiple simulated star points correspond to a superimposed control wavefront in the light field control device 3. Multiple simulated star points correspond to a superimposed control wavefront, and multiple simulated star points are generated by controlling the superimposed control wavefront in the light field control device 3.

[0074] In step S3, the spatial frequency expansion device 4 is used to perform spatial frequency expansion on the outgoing control light field. The spatial frequency expansion device 4 performs processing by dispersing and reorganizing the spatial domain information of the light field through laser expansion and scattering medium. Specifically,

[0075] The laser light source 1 is expanded into multiple laser beams in a two-dimensional plane distributed manner, and irradiated to the light field control device 3 at different incident angles. The light field control device 3 controls the multiple laser beams to obtain multiple controlled light fields with different exit angles; the controlled light fields with multiple different exit angles are irradiated to different positions of the scattering medium; by analyzing the scattering transmission process of the scattering medium, the transformation relationship of the light field before and after scattering is determined, and then the light field wavefront information required to be controlled by the light field control device 3 and the corresponding lasers required to be selected in the multiple laser beams are determined according to the simulated star points; the selected laser is controlled by the light field control device 3, and the photons of the output controlled light field propagate in the scattering medium in a specified orbit deviating from the original propagation direction, thereby expanding the original spatial frequency; the photons converge together after scattering to generate simulated star points; by switching the selection of multiple laser beams and the control information of the light field control device 3, a large range of simulated star points with an expanded field of view are generated.

[0076] Preferably, the spatial frequency expansion device 4 is realized by sub-aperture splicing of the light field control device 3: the light field control device 3 performs two-dimensional plane distributed expansion into a plurality of spliced ​​light field control devices 3, and the laser light source 1 irradiates the plurality of spliced ​​light field control devices 3; the laser light source 1 is subjected to pixel-level gating control by the plurality of spliced ​​light field control devices 3, and becomes a point light source that only radiates from the gated pixels; the point light source is collimated and irradiated to the aberration correction device, and after the aberration is corrected, it is converged into simulated star points through the optical system; through different gating controls of the plurality of spliced ​​light field control devices 3, a large range of simulated star points with an expanded field of view are generated.

[0077] In step S4, the micro-angle light field control device 5 is used to control the simulated star point at a micro-angle. The micro-angle light field control device 5 deflects the simulated star point at an angle by rotating the wedge-shaped prism to generate a cross-scale star point simulation target. The specific process is as follows:

[0078] After being collimated, the simulated star point becomes a parallel light beam and is incident on a wedge-shaped prism. When the wedge-shaped prism is rotated, the parallel light beam is deflected at a small angle due to the angle between different surfaces of the wedge-shaped prism, thereby generating a cross-scale star point simulation target with high moving accuracy.

[0079] Alternatively, the micro-angle light field control device 5 deflects the light beam at a small angle through a deflection reflector to generate a cross-scale star point simulation target. The specific process is:

[0080] After being collimated, the simulated star point becomes a parallel light beam and is incident on the reflector; by deflecting the reflector at a small angle, the parallel light beam is deflected at a small angle, generating a cross-scale star point simulation target with high movement accuracy.

[0081] In step S5, the effective aperture of the cross-scale star point simulation target is expanded by using the aperture matching output device 6, the aperture matching output device 6 includes an aperture adjustment optical element, and the processing process of the aperture matching output device 6 is specifically as follows:

[0082] The cross-scale star point simulation target is incident on the aperture adjustment optical element to obtain collimated and expanded parallel light. Due to the focal length ratio of the aperture adjustment optical element, the movement angle of the collimated and expanded parallel light is further reduced, and the movement accuracy of the star point simulation target is further improved, generating the target parallel light required for cross-scale ultra-high precision star sensor calibration.

[0083] like Figure 1 As shown, this embodiment also provides a celestial body star point simulation device for realizing the above-mentioned celestial body star point simulation method based on light field control, including a laser light source 1, a collimating beam expansion device 2, a light field control device 3, a spatial frequency expansion device 4, a micro-angle light field control device 5, an aperture matching output device 6 and a main control computer 8;

[0084] The light emitted by the laser light source 1 generates a collimated light beam after passing through the collimating beam expansion device 2; the collimated light beam is input into the light field control device 3 at a specific incident angle, and is controlled by the light field control device 3 to become an outgoing control light field with controllable wavefront; the outgoing control light field passes through the spatial frequency expansion device 4 to generate a single or several simulated star points in a larger range; the simulated star points then pass through the micro-angle light field control device 5 to generate cross-scale star point simulation targets; the cross-scale star point simulation targets pass through the aperture matching output device 6 to obtain a single or several target parallel lights required for star sensor calibration; the main control computer 8 is used to control the control information of the light field control device 3, the spatial frequency expansion device 4 and the micro-angle light field control device 5 to generate a target control light field.

[0085] Optionally, the laser light source 1 is a monochromatic light source; after the light emitted by the monochromatic light source is collimated and expanded, it is irradiated to the light field control device 3 at a specific incident angle and is controlled to become an output controlled light field.

[0086] Alternatively, the laser light source 1 is a wide-spectrum light source; the light emitted by the wide-spectrum light source is dispersed and collimated to generate a plurality of monochromatic light beams propagating in different directions, which are irradiated with the light field control device 3 at different incident angles and are controlled to become a controlled light field with the same output angle; the controlled light field passes through the spatial frequency expansion device 4 to generate a large range of multi-wavelength simulated star points.

[0087] Optionally, the light field control device 3 is a light field control device 3 based on a digital micromirror array; the digital micromirror array uses diffraction to control the wavefront information of the laser light source 1 to generate an output controlled light field.

[0088] Alternatively, the light field control device 3 is a light field control device 3 based on a liquid crystal spatial light modulator; the liquid crystal spatial light modulator uses diffraction to control the wavefront information of the laser light source 1 to generate an output controlled light field.

[0089] The parallelism of the target parallel light is monitored by interferometers such as collimators; the target parallel light passes through the spectroscopic optical element, a part of it is used as the calibration input of the star sensor, and the other part is incident on the interferometer for parallelism monitoring, and then the light field control information of the light field control device 3, the spatial frequency expansion device 4, and the micro-angle light field control device 5 is fed back to control.

[0090] The target parallel light is used for cross-scale ultra-high precision sensor calibration through synchronous control between the light field control device 3, the spatial frequency expansion device 4, the micro-angle light field control device 5 and the sensor; the synchronous control coordinates the star point target simulation time and the sensor image acquisition time.

[0091] Correspondingly, such as Figure 2 As shown, the working principle of the above-mentioned celestial body star point simulation device includes the following steps:

[0092] S101: Turn on laser light source 1;

[0093] S102: collimate and expand the light source, and input the light beam into the light field control device 3;

[0094] S103: Calculating the light field distribution to be regulated by the main control computer 8;

[0095] S104: generating an outgoing controlled light field having specific wavefront information by controlling the light field control device 3;

[0096] S105: inputting the spatial frequency expansion device 4 to generate a single or several simulated star points in a large range;

[0097] S106: Produce a large-scale, high-precision moving cross-scale star point simulation target through the micro-angle light field control device 5;

[0098] S107: converting the cross-scale star point simulation target into a single or multiple target parallel lights through the aperture matching output device 6;

[0099] S108: Obtain the desired cross-scale extremely high-precision star point simulation target;

[0100] S109: used for calibration of extremely high precision astrometric sensor 7.

[0101] Example 2

[0102] like Figure 3 As shown, this embodiment provides a celestial star point simulation device of a celestial star point simulation method based on light field control, which is substantially the same as the celestial star point simulation device in Example 1, except that the light field control device 3 includes a digital micromirror array 301 and a focusing mirror 302, the spatial frequency expansion device 4 mainly includes a fiber beam splitter 401, a scattering medium 402 and a second collimator 403, a first collimator 201 is arranged at the output end of the fiber beam splitter 401 to realize collimation and beam expansion, the micro-angle light field control device 5 includes a wedge prism 501, a first rotating stage 502, and a second rotating stage 503, and the aperture matching output device 6 includes a focusing mirror 601 and a third collimator 602.

[0103] The laser 1 wavelength of the celestial star point simulation system with cross-scale and extremely high precision based on light source expansion and scattered light field control is 560nm. Figure 4 This is a simulation flow chart. The specific simulation process is as follows:

[0104] S201: Turn on laser light source 1;

[0105] S202: The laser light source 1 is distributed and expanded in a matrix manner on a two-dimensional plane through an optical fiber beam splitter, divided into multiple light beams, and collimated by a collimator to illuminate the digital micromirror array, and the incident angles of the collimated lights from different light sources are different;

[0106] S203: generating the required regulated light field distribution through the main control computer 8 and determining the required input light source beam;

[0107] S204: Selecting the light source beam and inputting it into the light field control device 3;

[0108] S205: Using the light field control device 3 to control the light field to generate a control light field with a specific angle output; that is, using a digital micromirror array to control the light beam wavefront;

[0109] S206: inputting the spatial frequency expansion device 4 to irradiate a specific position of the scattering medium; that is, focusing the outgoing regulated light field on the scattering medium, and different collimated incident lights will be focused on different positions of the scattering medium;

[0110] S207: The scattered light is converged into a focus to generate a simulated star point; that is, the light field is regulated to form a focus point behind the scattering medium to generate a simulated star point. Different collimated incident lights form focus points in different areas behind the scattering medium. By selecting different light sources of the extended light source and switching different regulation information of the digital micromirror array, a large range of simulated star points can be formed in multiple areas spliced ​​together.

[0111] S208: After being collimated and input into the micro-angle light field control device 5, the light beam is refracted by the rotating wedge prism; that is, the simulated star point is collimated and incident into the wedge prism placed on the rotating table, and the wedge prism can rotate around the x and y axes, and the collimated light is deflected at a smaller angle accordingly;

[0112] S209: Obtain cross-scale target parallel light through the aperture matching output device 6; that is, further enter the beam expansion system composed of two lenses, and the focal length ratio of the beam expansion system also further reduces the deflection angle of the 4 light beams, generating large-aperture cross-scale target parallel light;

[0113] S210: Input the interferometer to evaluate the divergence angle and deflection accuracy of the parallel light; if the standard is not met, the control information is optimized by the main control computer and returns to step S203; if the standard is met, the required cross-scale ultra-high-precision star point simulation target with a large moving range and high moving accuracy is obtained, and the astronomical measurement sensor 7 is input to calibrate the instrument. The main control computer 8 controls the synchronization signal and feeds it back to steps S205 and S208.

[0114] That is, the target parallel light is split by the beam splitter 9, one beam enters the collimator 10 to detect parallelism, and the control information of the optimized digital micromirror array is fed back through the main control computer 8, and the other beam enters the astrometric sensor 7 for extremely high-precision sensor calibration.

[0115] Among them, how to determine the light beam wavefront that needs to be controlled by the digital micromirror array requires analyzing the light field transformation before and after the scattering medium. Figure 5This is the schematic diagram of the scattering medium analysis. The specific analysis process is as follows:

[0116] 1. After the laser light source 1 is collimated, it is incident on the digital micromirror array. The digital micro-array is loaded with a random control pattern and forms speckles through the scattering medium;

[0117] 2. Use the photoelectric detector 11 to detect the light intensity value at the target focus point behind the scattering medium, and use the light intensity value as a feedback value to iteratively optimize the control pattern of the digital micromirror array through the main control computer 8 to increase the light intensity value;

[0118] 3. When the light intensity value converges to the optimal value, a digital micromirror array control wavefront corresponding to a simulated star point is obtained. By moving the photodetector to detect the light intensity values ​​of other points and repeating the above process, the control wavefronts corresponding to other simulated star points can be obtained.

[0119] Example 3

[0120] This embodiment is substantially the same as Embodiment 2, except that Figure 6 As shown, in the celestial star point simulation device of the celestial star point simulation method based on light field control provided in this embodiment, the light field control device 3 and the spatial frequency expansion device 4 are combined together, mainly including components: a digital micromirror array splicing system 311 and a deformable mirror 313, and the corresponding specific components are the digital micromirror array splicing system 311, the fourth collimating mirror 312, the deformable mirror 313, the focusing mirror 314 and the fifth collimating mirror 315 distributed in sequence; the micro-angle light field control device 5 includes a reflecting mirror 511 and a deflection table 512, and the aperture matching output device 6 includes a focusing mirror 601 and a third collimating mirror 602.

[0121] Figure 7 This is a schematic diagram of the structure of a digital micromirror array splicing system, which is constructed by splicing multiple digital micromirror arrays in a two-dimensional matrix.

[0122] The star point simulation steps of this embodiment are similar to those of embodiment 1, with the specific difference being:

[0123] 1. The light source does not need to be distributed and expanded. The aperture of the light source only needs to cover the digital micromirror array splicing system.

[0124] 2. Use digital micromirror array splicing system to expand the star point simulation range without light source extension and scattering medium;

[0125] 3. Star point simulation is mainly achieved by opening pixel-level micromirrors. A single star point is achieved by opening a point light source formed by a single pixel-level micromirror, where the deformable mirror is a point light source aberration compensation device;

[0126] 4. The high-precision movement of the simulated star point is achieved by light reflection from a reflector placed on an extremely high-precision tilt table;

[0127] 5. The parallelism of the target parallel light is detected by the interferometer 12.

[0128] The structure of digital micromirror array splicing system 311 is as follows Figure 7 As shown, multiple digital micromirror arrays 301 are spliced ​​in a two-dimensional matrix to form a digital micromirror array splicing system 311, where 3111 is a closed pixel-level micromirror and 3112 is an open pixel-level micromirror. The splicing system simulates the star point by turning off most of the micromirrors and only turning on specific pixel-level micromirrors to form a point light source. A single pixel-level micromirror corresponds to a single simulated star point, and the realization of multiple star points requires turning on multiple pixel-level micromirrors.

[0129] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for simulating celestial star points based on light field control, characterized in that: The following steps are involved: Generating a laser light source (1), and performing collimation and beam expansion on the laser light source (1) to generate a collimated light beam; Modulate the wavefront information of the light field of the collimated light beam to obtain an outgoing controlled light field; Perform spatial frequency expansion on the outgoing regulated light field to obtain a single or several simulated star points with a larger range of field expansion; The simulated star points are controlled at micro-angles to generate cross-scale star point simulation targets that can be precisely moved at an angle within the expanded viewing angle range. The effective aperture of the cross-scale star point simulation target is adjusted and matched to obtain a single or several target parallel lights for star sensor calibration.

2. The method for simulating celestial star points based on light field control according to claim 1, characterized in that: A light field control device (3) is used to modulate light field wavefront information of a collimated light beam, wherein the light field control device (3) performs modulation by a super-pixel control method based on a digital micromirror array, a Lee-type computational holographic method based on a digital micromirror array, or a binary encoding method based on a digital micromirror array; The super-pixel control method based on digital micromirror array is specifically as follows: The collimated light beam incident into the light field control device (3) is irradiated onto the digital micromirror array, and each p of the digital micromirror array is x ×p y Adjacent micromirrors form a super-pixel, and the complex amplitude wavefront of the corresponding point in the collimated light beam is regulated by binary intensity control of turning on and off the micromirrors contained in the super-pixel; the diffracted light on the diffraction order regulated by the super-pixel is selected by the optical system to generate the output regulated light field; The Lee-type computer-generated holographic method based on digital micromirror array is specifically as follows: The collimated light beam incident into the light field control device (3) is irradiated on the digital micromirror array, and the stripe grating is loaded by the digital micromirror array for control, the phase information of the collimated light beam is encoded as the stripe position of the grating, and the amplitude information is encoded as the stripe peak and valley value of the grating, and the regulated diffracted light is selected by the optical system to generate the output controlled light field; The binary encoding method based on digital micromirror array is specifically as follows: The collimated light beam incident into the light field control device (3) is irradiated on the digital micromirror array, and the digital micromirror array performs binary intensity control of on and off, and the regulated diffracted light is selected by the optical system to generate the output controlled light field.

3. The method for simulating celestial star points based on light field control according to claim 1, characterized in that: A light field control device (3) is used to modulate the light field wavefront information of the collimated light beam, and the light field control device (3) generates an output control light field having specific information on the required wavefront based on a liquid crystal spatial light modulator.

4. The method for simulating celestial star points based on light field control according to claim 1, characterized in that: A light field control device (3) is used to modulate the light field wavefront information of the collimated light beam, a single simulated star point corresponds to one control information in the light field control device (3), and a plurality of simulated star points correspond to a plurality of control information in the light field control device (3), and a movable single or multiple simulated star points are generated by switching the control information in the light field control device (3); A single simulated star point corresponds to a control wavefront in the light field control device (3), and a plurality of simulated star points correspond to a superimposed control wavefront in the light field control device (3). The plurality of simulated star points are generated by controlling the superimposed control wavefront in the light field control device (3).

5. The method for simulating celestial star points based on light field control according to claim 1, characterized in that: A spatial frequency expansion device (4) is used to expand the spatial frequency of the output regulated light field. The processing process of the spatial frequency expansion device (4) is specifically as follows: The laser light source (1) is expanded in a two-dimensional plane distributed manner into a plurality of laser light beams with different emission angles, and a laser light beam is selected from the laser light beams to obtain a plurality of emission control light fields with different emission angles through modulation of light field wavefront information, so as to expand the star point simulation range and irradiate the scattering medium; the scattering medium expands the propagation track of the photons of the emission control light field, further expanding the control spatial frequency; the photons are scattered by the scattering medium and converged, so as to generate a single or a plurality of simulated star points with a larger range of expanded field of view.

6. The method for simulating celestial star points based on light field control according to claim 1, characterized in that: The light field control device modulates the light field wavefront information of the collimated light beam to obtain an outgoing controlled light field; and performs spatial frequency expansion on the outgoing controlled light field to obtain a single or multiple simulated star points with a larger range of field expansion, specifically: The collimated light beam is gated and regulated at the pixel level by the digital micromirror array splicing system, and becomes a point light source that only emits from the gated pixel; the point light source is collimated and aberration corrected, and then converged into a simulated star point by the optical system; The digital micromirror array splicing system is composed of multiple digital micromirror arrays spliced ​​in a two-dimensional plane matrix; By gating and regulating different pixels of the digital micromirror array splicing system, simulated star points with an extended field of view are generated.

7. The method for simulating celestial star points based on light field control according to claim 1, characterized in that: A micro-angle light field control device (5) is used to control the simulated star point at a micro-angle. The micro-angle light field control device (5) deflects the simulated star point at an angle by rotating a wedge prism or a deflection reflector to generate a cross-scale star point simulation target. The specific process is as follows: The simulated star point is collimated to become a parallel light beam, which is incident on a wedge-shaped prism or a reflector; by rotating the wedge-shaped prism or the deflection reflector, the parallel light beam is deflected at an angle to generate a cross-scale star point simulation target.

8. The method for simulating celestial star points based on light field control according to claim 1, characterized in that: An aperture matching output device (6) is used to adjust the effective aperture of the cross-scale star point simulation target. The aperture matching output device (6) comprises an aperture adjustment optical element. The processing process of the aperture matching output device (6) is specifically as follows: The cross-scale star point simulation target is incident on the aperture adjustment optical element to obtain collimated parallel light with an aperture matching the star sensor, and based on the focal length ratio of the aperture adjustment optical element, the movement angle of the collimated parallel light is further reduced to obtain a single or multiple target parallel lights for star sensor calibration.

9. A celestial body star point simulation device for implementing a celestial body star point simulation method based on light field control as claimed in any one of claims 1 to 8, characterized in that: It comprises a laser light source (1), a collimating beam expansion device (2), a light field control device (3), a spatial frequency expansion device (4), a micro-angle light field control device (5), an aperture matching output device (6) and a main control computer (8); The light emitted by the laser light source (1) generates a collimated light beam after passing through the collimating beam expansion device (2); the collimated light beam is input into the light field control device (3) at a specific incident angle, and is controlled by the light field control device (3) to become an outgoing controlled light field with controllable wavefront; the outgoing controlled light field passes through the spatial frequency expansion device (4) to generate a single or multiple simulated star points in a larger range; the simulated star points then pass through the micro-angle light field control device (5) to generate cross-scale star point simulated targets that can move at precise angles within the expanded viewing angle range; the cross-scale star point simulated targets pass through the aperture matching output device (6) to obtain a single or multiple target parallel lights required for star sensor calibration; the main control computer (8) is used to synchronously control the control information of the light field control device (3), the spatial frequency expansion device (4) and the micro-angle light field control device (5).

10. The device according to claim 9, characterized in that The laser light source (1) is a monochromatic light source or a broadband light source; After the light emitted by the monochromatic light source passes through the collimating beam expanding device (2), it is irradiated to the light field regulating device (3) at a specific incident angle and is regulated to become the output regulated light field; The light emitted by the broadband light source is collimated and expanded by the collimating and expanding device (2) to generate a broadband light beam, which irradiates the light field regulating device (3) and is regulated to become the output regulated light field.

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