Telescope optical receiving system and method of receiving thereof

Abstract

The present application belongs to the field of deep space communication, and particularly relates to a telescope optical receiving system and a receiving method thereof, which comprises an optical spliced primary mirror, a secondary mirror, a tertiary mirror, an optical receiving terminal, a primary mirror support assembly, a tracking compensation assembly and a processor; the optical spliced primary mirror is installed on the primary mirror support assembly, the primary mirror support assembly is connected with a dome support truss through the dome support truss, the secondary mirror is installed on a secondary mirror moving bearing mechanism, the secondary mirror moving bearing mechanism is installed on a dome bearing frame, the tertiary mirror is located in the reflection direction of the secondary mirror, the optical receiving terminal is located in the reflection direction of the tertiary mirror, and is used for receiving target light signals of a target and calculating tracking errors; the tracking compensation assembly is used for tracking a target light spot and compensating the optical receiving terminal; and the processor is used for controlling the segmented mirror actuator, the secondary mirror moving bearing mechanism and the tracking compensation assembly according to the tracking errors. The present application can improve the tracking precision of the target.

Description

Technical Field

[0001] This invention belongs to the field of deep space communication technology, and particularly relates to a telescope optical receiving system and its receiving method. Background Technology

[0002] The data transmission capability of deep space exploration missions is continuously improving. With the development of high-resolution remote sensing, continuous imaging, video observation, on-orbit intelligent processing and data transmission, and manned deep space missions, traditional radio frequency ground stations are facing increasingly significant constraints in terms of spectrum resources, aperture efficiency, and the amount of information that can be transmitted per unit time. In recent years, demonstrations of deep space optical communication technology have clearly shown that laser communication can achieve significantly higher data transmission capabilities over deep space distances than traditional radio frequency links, and is being identified as an important direction for high data rate data transmission in future lunar and Martian missions.

[0003] Existing technologies include "RF-optical hybrid antenna" solutions. The core technical features of this solution can be summarized as follows: using an existing RF antenna as a platform, embedding a segmented optical receiving aperture telescope in its central area or at an appropriate location; employing active control of the lens segments to maintain the optical aperture geometry; achieving stable focal plane reception through a camera, a rapid steering mechanism, and fiber optic coupling; and placing high-sensitivity detectors and decoding equipment behind the antenna base or in a control room, thereby reducing the burden on high-altitude servo components and utilizing existing RF links to provide target acquisition, telemetry, timing, and backup capabilities in adverse weather conditions. This solution has validated the overall direction of "integrated RF and laser operation."

[0004] However, the existing solutions mentioned above still have the following shortcomings: First, existing external guide mirrors or side trackers measure auxiliary optical path errors and cannot fully reflect the true error of the communication beam within the telescope's effective aperture. When the light signal from deep-space targets is weak, the field of view is small, and fiber optic coupling requirements are high, this type of non-co-aperture tracking method is prone to residual errors, affecting the efficiency of weak light reception.

[0005] Secondly, existing telescopes are mostly designed with a fixed effective aperture. However, the effective receiving sub-aperture of the telescope may vary under different fields of view, different optical path branches, and different target incident angles. Without establishing a dynamic evaluation and compensation mechanism for the effective aperture, inconsistencies in the equivalent aperture may occur between the acquisition optical path, the tracking optical path, and the communication receiving optical path, leading to tracking errors and a decrease in coupling efficiency. Summary of the Invention

[0006] In view of this, the present invention aims to provide a telescope optical receiving system and method to solve the problem that existing radio frequency-optical hybrid antenna solutions cannot further improve tracking accuracy.

[0007] To achieve the above objectives, the technical solution created by this invention is implemented as follows: A telescope optical receiving system includes: an optical splicing primary mirror, a secondary mirror, a third mirror, an optical receiving terminal, a primary mirror support assembly, a tracking compensation assembly, a processor, a dome support frame, a secondary mirror moving support mechanism, and a dome support truss. One end of the dome support truss is connected to the main mirror support assembly, and the other end of the dome support truss is connected to the dome load-bearing frame. The optical splicing primary mirror is mounted on the primary mirror support assembly. The optical splicing primary mirror adopts a primary mirror array composed of multiple segmented mirrors. Each segmented mirror is adjusted by an independent segmented mirror actuator. The secondary mirror is located in the reflection direction of the optical splicing primary mirror and is mounted on the secondary mirror moving support mechanism. The secondary mirror moving support mechanism is mounted on the dome support frame. The position of the secondary mirror relative to the optical splicing primary mirror is adjusted through the secondary mirror moving support mechanism. The three mirrors are located in the reflection direction of the secondary mirror and are set behind the optical splicing primary mirror; The optical receiving terminal is located in the reflection direction of the three mirrors and is used to receive the target light signal emitted by the target and reflected sequentially by the optical splicing primary mirror, secondary mirror and third mirror, and to calculate the tracking error; The tracking compensation component is used to track the target light spot and compensate the optical receiving terminal; The processor is used to control the segmented mirror actuator, the secondary mirror moving support mechanism, and the tracking compensation component based on the tracking error calculated by the optical receiving terminal.

[0008] Furthermore, a light-transmitting aperture is formed in the central region of the primary mirror array, through which the target light signal reflected by the secondary mirror passes and enters the three mirrors.

[0009] Furthermore, the optical receiving terminal includes a focusing lens group, a narrowband filter, an optical fiber coupler, and a photonic neural network arranged sequentially along the propagation path of the target optical signal.

[0010] Furthermore, the tracking compensation component includes a first beam splitter, a second beam splitter, a camera, a focal plane detector, a fast-steering mirror, and a focusing mechanism. The focusing mechanism is used to adjust the position of the focusing mirror group to achieve focusing of the optical receiving terminal. The first beam splitter is disposed between the narrowband filter and the fiber coupler. The camera is disposed in the reflected light path of the first beam splitter to capture and track the target light spot. The second beam splitter is disposed in the transmitted light path of the first beam splitter. The focal plane detector is disposed in the reflected light path of the second beam splitter to achieve focal plane detection of the target light spot. The fast-steering mirror is disposed in the transmitted light path of the second beam splitter, and the fiber coupler is disposed in the exit direction of the fast-steering mirror.

[0011] Furthermore, the optical receiving terminal also includes a Hartmann wavefront sensing component and a third beam splitter. The third beam splitter is positioned between the second beam splitter and the fast-steering mirror, and the Hartmann wavefront sensing component is positioned in the reflected light path of the third beam splitter for measuring the wavefront slope.

[0012] Furthermore, the photonic neural network includes a diffraction grating, a microlens array, and a photodetector. The diffraction grating is used to diffract and split the target light signal output from the fiber coupler; the microlens array is used to converge the multiple sub-beams formed after the diffraction grating splits the light; and the photodetector is used to perform photoelectric conversion on the incident multiple sub-beams.

[0013] A telescope optical receiving method, implemented using the aforementioned telescope optical receiving system, includes the following steps: S1: Track the target by using the optical splicing primary mirror, secondary mirror, tertiary mirror, and optical receiving terminal; S2: Determine the effective set of sub-apertures on the current optical splicing primary mirror used for tracking the target to form the target spot; S3: The target light spot is tracked by the tracking compensation component, and the tracking error is calculated by the optical receiving terminal. The tracking compensation component then compensates the optical receiving terminal based on the tracking error. The process of calculating the tracking error includes: Target optical signals of different wavelengths are incident on the photonic neural network of the optical receiving terminal; The target light signal of different wavelengths is diffracted and split by the diffraction grating in the photonic neural network to form multiple sub-beams; Multiple sub-beams are converged by a microlens array in a photonic neural network to a photodetector in the photonic neural network for photoelectric conversion, forming a detection pattern; The optical path difference between the two interfering sub-beams is extracted from the detection pattern, and then the optical path difference is converted into tracking error; S4: The processor controls the segmented mirror actuator, the secondary mirror moving support mechanism, and the tracking compensation component based on the tracking error.

[0014] Furthermore, in step S2, the multiple segmented mirrors constituting the optical splicing primary mirror are divided into different sub-apertures, the effective weight of each sub-aperture is calculated, and sub-apertures that meet the conditions are selected according to the preset weight threshold. Let the first The geometric area of ​​each aperture is The sub-aperture at the current field of view and the current moment The effective weights are : ;

[0015] in, Indicates the geometric illumination weights of the field of view. Indicates occlusion weight. Indicates the signal-to-noise ratio weight. Indicates wavefront stability weights. The value represents the contribution weight of fiber coupling, and E represents the total number of sub-apertures.

[0016] Furthermore, in step S2, the stability of the effective sub-aperture set is evaluated using the Hartmann wavefront sensing component: Suppose that the Hartmann wavefront sensing assembly contains M sampling units, and measure the wavefront slope of each sampling unit:

[0017]

[0018] ; ; in, and This represents the wavefront slope of the i-th sampling unit in the X and Y directions; This indicates the focal length of the microlens inside the Hartmann wavefront sensing component; and This indicates the position of the reference spot in the i-th sampling unit; and This indicates the position of the light spot currently measured by the i-th sampling unit; and This represents the deviation of the light spot in the X and Y directions of the i-th sampling unit; t represents the current time. The wavefront slopes of the M sampling units are combined to form a wavefront slope measurement vector; ; Calculating wavefront coefficients using wavefront slope measurement vectors : ; , ; in, Represents the slope response matrix. Represents the regularization coefficient. Represents the dynamic weight matrix. Represents the identity matrix. Indicates matrix transpose; This represents the overall effective weight of the i-th sampling unit of the Hartmann wavefront sensing component; Represents a diagonal matrix; Based on wavefront coefficients Reconstructing the full-aperture wavefront error function :

[0019] in, Indicates the first The basis functions of the Zernik polynomial, where K represents the total number of terms in the Zernik polynomial; Represents the normalized polar coordinates on the plane of the effective aperture of the optical splicing primary mirror; The center coordinates of the i-th sub-aperture in the effective sub-aperture set Substitute into the full-aperture wavefront error function obtained from reconstruction The reconstructed wavefront error at the i-th sub-aperture in the effective sub-aperture set is obtained. : ; Based on the reconstructed wavefront error at the i-th sub-aperture in the effective sub-aperture set Calculate the root mean square wavefront error within the current effective aperture of the optical splicing primary mirror. :

[0020] in, This represents the effective sub-aperture weighted average wavefront error. This indicates the number of sub-apertures in the effective sub-aperture set; Based on the root mean square wavefront error within the current effective aperture of the optical splicing primary mirror The wavefront stability factor of the current effective aperture of the optical splicing primary mirror is calculated to evaluate the stability of the effective sub-aperture set. :

[0021] in, Indicates the wavelength of the target optical signal.

[0022] Furthermore, in step S4, the processor assigns control quantities to the segmented mirror actuator, the secondary mirror moving support mechanism, and the focusing mechanism and fast-turning mirror in the tracking compensation assembly according to the tracking error.

[0023] Compared with the prior art, the present invention can achieve the following beneficial effects: First, this invention addresses the problem of changes in the effective aperture of the optical splicing primary mirror under different fields of view by introducing a dynamic evaluation mechanism for the effective sub-aperture, enabling the acquisition and tracking of targets to be corrected according to the actual effective aperture, thereby achieving precise tracking of targets.

[0024] Second, the present invention distributes control quantities to the segmented mirror actuator, the secondary mirror moving support mechanism, the focusing mechanism, and the fast turning mirror according to the tracking error, thereby completing the self-tracking closed loop and avoiding over-reliance on external guide mirrors or side trackers, thus more realistically reflecting the true error within the effective aperture of the telescope.

[0025] Third, by building a photonic neural network, the co-phase adjustment of the optical splicing primary mirror is achieved. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the structure of the telescope optical receiving system described in an embodiment of the present invention; Figure 2 A schematic diagram of the structure of the optical splicing primary mirror described in an embodiment of the present invention; Figure 3 A schematic diagram of the logical structure of the optical receiving terminal and the tracking compensation component as described in the embodiments of the present invention; Figure 4 A schematic diagram of the structure of the photonic neural network described in the embodiment of the present invention; Figure 5 This is a schematic flowchart of the telescope optical receiving method described in an embodiment of the present invention.

[0027] Figure labeling: 1. Optical splicing primary mirror, 11. Segmented mirror, 2. Secondary mirror, 3. Third mirror, 4. Optical receiving terminal, 41. Focusing mirror group, 42. Narrowband filter, 43. Fiber optic coupler, 44. Photonic neural network, 45. Diffraction grating, 46. Microlens array, 47. Photodetector, 48. Hartmann wavefront sensing component, 49. Third beam splitter, 5. Primary mirror support component, 6. Dome support frame, 7. Secondary mirror moving support mechanism, 8. Dome support truss, 91. First beam splitter, 92. Second beam splitter, 93. Camera, 94. Focal plane detector, 95. Quick-turn mirror, 96. Focusing mechanism, 10. Target. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0030] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "assembly," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] like Figures 1-4 As shown, this invention provides a telescope optical receiving system, including an optical splicing primary mirror 1, a secondary mirror 2, a third mirror 3, an optical receiving terminal 4, a primary mirror support assembly 5, a dome support frame 6, a secondary mirror moving support mechanism 7, a dome support truss 8, a tracking compensation assembly, and a processor. The optical splicing primary mirror 1 is mounted on the primary mirror support assembly 5. The primary mirror 1 employs a primary mirror array, with a light-passing aperture formed in the central region of the array. The primary mirror array is composed of multiple hexagonal segmented mirrors 11, each segmented mirror 11 having its pose adjusted by an independent segmented mirror 11 actuator. The primary mirror support assembly 5 is connected to the dome support frame 6 via the dome support truss 8. Figure 2As shown, multiple segmented mirrors 11 ideally form a spherical optical splicing primary mirror. However, in the actual tracking of the target 10, the pose of each segmented mirror 11 needs to be adjusted. The multiple segmented mirrors 11 ultimately form an aspherical surface to correct the imaging aberrations of the target 10, achieving co-phase imaging. The secondary mirror 2 is located in the reflection direction of the optical splicing primary mirror 1, i.e., on the reflecting surface of the optical splicing primary mirror 1. The secondary mirror 2 is mounted on the secondary mirror moving support mechanism 7, which is mounted on the dome support frame 6. The secondary mirror moving support mechanism 7 is used to adjust the position of the secondary mirror 2 relative to the optical splicing primary mirror 1. The third mirror 3 is located in the reflection direction of the secondary mirror 2 and is positioned on the back of the optical splicing primary mirror 1. The optical receiving terminal is positioned in the reflection direction of the third mirror 3, receiving the target light signals reflected sequentially by the optical splicing primary mirror 1, secondary mirror 2, and third mirror 3. The tracking compensation component is used to track the target light spot and compensate the optical receiving terminal. The processor is used to control the optical splicing primary mirror 1, secondary mirror 2, and tracking compensation components based on the tracking error calculated by the optical receiving terminal.

[0034] The target light signal emitted by target 10 is first incident on the optical splicing main mirror 1, reflected by the optical splicing main mirror 1 to the secondary mirror 2, then reflected by the secondary mirror 2 and passed through the light-transmitting hole of the optical splicing main mirror 1 before being incident on the third mirror 3, and finally reflected by the third mirror 3 into the optical receiving terminal 4 for subsequent signal processing.

[0035] In this invention, the effective aperture of the telescope is not always equal to the fixed geometric aperture. Due to the obstruction of the dome support frame 6, the secondary mirror moving support mechanism 7, and the dome support truss 8, as well as the change in the incident field of view of the target 10, the range of sub-apertures participating in optical reception may be different under different fields of view.

[0036] Therefore, this invention divides the optical splicing primary mirror 1 into several effective sub-apertures. Each sub-aperture corresponds to a weight, which is determined by one or more of the following factors: The illumination area of ​​the sub-aperture in the current field of view; the contribution of the sub-aperture to the target spot energy; the wavefront error corresponding to the sub-aperture; the sharpness of the focal spot corresponding to the sub-aperture; the contribution of the sub-aperture to the fiber coupling efficiency; whether the sub-aperture is blocked by the RF sub-reflector or truss structure.

[0037] When target 10 is in the wide field-of-view acquisition phase, the telescope optical receiving system can use a larger search field of view and part of the effective aperture to improve the acquisition probability; when target 10 enters the guidance phase, the telescope optical receiving system expands the effective aperture and improves the tracking accuracy; when target 10 enters the communication receiving phase, the telescope optical receiving system selects the optimal effective aperture combination according to the fiber coupling efficiency to improve the coupling stability.

[0038] Through this mechanism, the present invention can adapt to the change in the effective aperture of the optical splicing primary mirror 1 under different fields of view, and avoid the tracking error caused by directly using a fixed aperture for common aperture reception.

[0039] The optical receiving terminal 4 includes a focusing lens group 41, a narrowband filter 42, an optical fiber coupler 43, and a photonic neural network 44, arranged sequentially along the propagation path of the target optical signal. The focusing lens group 41 is located in the optical path behind the optical splicing main mirror 1, at the incident end of the optical receiving terminal 4, and is used to compensate for aberrations introduced by the optical splicing main mirror 1. The narrowband filter 42 is used to filter out background light and stray light. The optical fiber coupler 43 is used to couple the target optical signal (after filtering out background and stray light) into the photonic neural network 44. The photonic neural network 44 is used to calculate the tracking error of the target 10. The tracking error includes aberrations of the target spot, focus deviation, wavefront error, and coupling deviation.

[0040] The tracking compensation assembly includes a first beam splitter 91, a second beam splitter 92, a camera 93, a focal plane detector 94, a fast-steering mirror 95, and a focusing mechanism 96. The focusing mechanism 96 drives the focusing mirror assembly 41 to move back and forth along the optical axis to focus the optical receiving terminal 4. The first beam splitter 91 is positioned between the narrowband filter 42 and the fiber optic coupler 43. The camera 93 is positioned in the reflected light path of the first beam splitter 91 to capture and track the target light spot. The second beam splitter 92 is positioned in the transmitted light path of the first beam splitter 91. The focal plane detector 94 is positioned in the reflected light path of the second beam splitter 92 to detect the focal plane of the target light spot. The fast-steering mirror 95 is positioned in the transmitted light path of the second beam splitter 92 to perform small-angle corrections on the target light signal, ensuring stable coupling of the target light signal to the fiber optic coupler 43. The fiber optic coupler 43 is positioned in the exit direction of the fast-steering mirror 95.

[0041] The optical receiving terminal also includes a Hartmann wavefront sensing component 48 and a third beam splitter 49. The third beam splitter 49 is disposed between the second beam splitter 92 and the fast-steering mirror 95. The Hartmann wavefront sensing component 48 is disposed in the reflected light path of the third beam splitter 49 and is used to measure the wavefront slope.

[0042] The photonic neural network 44 includes a diffraction grating 45, a microlens array 46, and a photodetector 47. The diffraction grating 45 is used to split the target light signal of different wavelengths output by the fiber coupler 43 to form multiple sub-beams in different directions. The microlens array 46 is multiple and is arranged in different propagation directions of the sub-beams. Figure 4 The diagram schematically shows two microlens arrays 46. Multiple microlens arrays 46 are used to converge multiple sub-beams from different directions to a photodetector 47. The photodetector 47 is used to perform photoelectric conversion on the incident multiple sub-beams.

[0043] The processor assigns control quantities to the actuator of segmented mirror 11, the secondary mirror moving support mechanism 7, and the focusing mechanism 96 and fast turning mirror 95 in the tracking compensation assembly according to the tracking error.

[0044] like Figure 5 As shown, this invention also provides a telescope optical receiving method, implemented using the aforementioned telescope optical receiving system, comprising the following steps: S1: Track the target by using optical splicing primary mirror, secondary mirror, tertiary mirror, and optical receiving terminal.

[0045] S2: Determine the set of effective sub-apertures on the current optical splicing primary mirror used for tracking the target to form the target spot.

[0046] Based on the current field of view, structural occlusion, spot energy distribution, wavefront quality, focal plane sharpness, and fiber coupling efficiency, the effective sub-aperture set on the optical splicing primary mirror used for tracking the target is determined, enabling dynamic evaluation of the effective aperture.

[0047] In step S2, the stability of the effective sub-aperture set is evaluated using the Hartmann wavefront sensing component: Suppose that the Hartmann wavefront sensing assembly contains M sampling units, and measure the wavefront slope of each sampling unit:

[0048]

[0049]

[0050] (4); in, and This represents the wavefront slope of the i-th sampling unit in the X and Y directions; This indicates the focal length of the microlens inside the Hartmann wavefront sensing component; and This indicates the position of the reference spot in the i-th sampling unit; and This indicates the position of the light spot currently measured by the i-th sampling unit; and This represents the deviation of the light spot in the X and Y directions of the i-th sampling unit; t represents the current time.

[0051] The wavefront slopes of the M sampling units are combined to form a wavefront slope measurement vector; (5).

[0052] Calculating wavefront coefficients using wavefront slope measurement vectors : (6); , (7); in, Represents the slope response matrix. Represents the regularization coefficient. Represents the dynamic weight matrix. Represents the identity matrix. Indicates matrix transpose; This represents the overall effective weight of the i-th sampling unit of the Hartmann wavefront sensing component.

[0053] Based on wavefront coefficients Reconstructing the full-aperture wavefront error function :

[0054] in, Indicates the first The basis functions of the Zernik polynomial, where K represents the total number of terms in the Zernik polynomial; Represents the normalized polar coordinates on the plane of the effective aperture of the optical splicing primary mirror; The center coordinates of the i-th sub-aperture in the effective sub-aperture set Substitute into the full-aperture wavefront error function obtained from reconstruction The reconstructed wavefront error at the i-th sub-aperture in the effective sub-aperture set is obtained. : ; Based on the reconstructed wavefront error at the i-th sub-aperture in the effective sub-aperture set Calculate the root mean square wavefront error within the current effective aperture of the optical splicing primary mirror. :

[0055] in, This represents the effective sub-aperture weighted average wavefront error. This indicates the number of sub-apertures in the effective sub-aperture set; Based on the root mean square wavefront error within the current effective aperture of the optical splicing primary mirror The wavefront stability factor of the current effective aperture of the optical splicing primary mirror is calculated to evaluate the stability of the effective sub-aperture set. :

[0056] in, Indicates the wavelength of the target optical signal.

[0057] when When the wavefront error increases, it indicates an increase in the current effective aperture, a widening of the beam, a decrease in focal plane quality, and a reduction in fiber coupling efficiency; when When the value is below a preset threshold, the system determines that the stability of the current effective caliber is insufficient.

[0058] This invention incorporates the wavefront stability factor into the calculation of effective caliber weights: (12); in, Indicates the geometric illumination weights of the field of view. Indicates occlusion weight. Indicates the signal-to-noise ratio weight. Indicates wavefront stability weights. This represents the contribution weight of fiber coupling.

[0059] When the wavefront stability weight of a certain sub-aperture is lower than a preset threshold, the processor may perform one or more of the following operations: Reduce the weight of the sub-aperture in the effective aperture calculation; reduce the weight of the sub-aperture in the tracking error solution; output surface correction amount to the corresponding segmented mirror actuator; output focal plane compensation amount to the focusing mechanism; output small angle correction amount to the fast turning mirror; temporarily remove the sub-aperture from the effective aperture set in case of severe instability.

[0060] In this way, the present invention extends Hartmann wavefront sensing from a traditional surface shape detection method to a dynamic effective aperture stability calculation method, enabling it not only to evaluate the image quality of optical systems, but also to determine which sub-apertures participate in communication reception and which sub-apertures should be deweighted or compensated in the current field of view, thereby improving the tracking accuracy of targets.

[0061] Necessity calculation and justification for the dynamic effective aperture of the optical splicing primary mirror: The effective aperture of the telescope described in this invention is not a fixed geometric aperture, but rather an equivalent receiving aperture that actually participates in laser communication reception and tracking calculation.

[0062] Suppose that the optical splicing primary mirror is composed of several sub-apertures, the first... The geometric area of ​​each aperture is Its current field of view (i.e., the angle between the target and the main reflector of the radio frequency antenna) and the current time The effective weights are This weight can be determined by the illumination area, occlusion ratio, reflection efficiency, wavefront stability, focal plane imaging quality, and fiber coupling contribution. Therefore, the current dynamic effective receiving area can be expressed as: (13); (14); in, Indicates the geometric illumination weights of the field of view. Indicates occlusion weight. Indicates the signal-to-noise ratio weight. Indicates wavefront stability weights. The value represents the contribution weight of fiber coupling, and E represents the total number of sub-apertures.

[0063] When a sub-aperture is affected by the RF sub-reflector, bridge structure, edge field cutoff, mirror misalignment, or wavefront degradation, its weight decreases; when the sub-aperture has a high illumination contribution, good wavefront quality, and high coupling contribution in the current field of view, its weight increases.

[0064] Corresponding dynamic effective caliber for:

[0065] Therefore, the optical receiver link calculation in this invention is no longer based on a fixed geometric aperture. With the core as the basis, and with a dynamic and effective caliber With the core as the core.

[0066] Let the communication distance be... The operating wavelength is The transmission power is Launch caliber is The emission aperture efficiency is The receiving aperture efficiency is The overall transmission coefficient of the link is Then the optical power at the receiving end It can be represented as:

[0067] Therefore, we can conclude that:

[0068] It is evident that as communication distance increases, the received power decreases by the square of the distance; while at the same distance, the received power is determined by the square of the current dynamic effective aperture. If only a large geometric aperture is present, but the number of effective sub-apertures actually participating in reception decreases, obstruction increases, or the wavefront deteriorates in the current field of view, then... As the power decreases, both the received power and the fiber coupling efficiency also decrease.

[0069] When the minimum required receive power is At that time, the following should be satisfied under the current field of view:

[0070] Right now

[0071] in:

[0072] Therefore, the key to this invention is not simply increasing the geometric aperture, but ensuring that the dynamic effective aperture always meets the minimum requirements of the link under different fields of view, different obstructions, and different operating conditions.

[0073] Photon energy for:

[0074] in, Let be Planck's constant. It is the speed of light. During the integration time... Internally, the number of effective photons received by the back-end detection link. for:

[0075] in, This refers to the backend detection quantum efficiency or equivalent detection efficiency. If the communication rate is... Then the number of effective photons received per bit is:

[0076] When the bit error rate or decoding threshold requires the number of photons per bit to meet the following:

[0077] in, The minimum number of received photons required per bit to meet the target bit error rate requirement; The maximum allowable communication rate under the current dynamic effective aperture condition. for:

[0078] Substituting into the received power expression, we get:

[0079] therefore:

[0080] In transmission time Internal data volume that can be returned for:

[0081] Right now

[0082] As can be seen from the above relationships, the present invention does not emphasize simply increasing the optical geometric aperture, but rather ensuring that the dynamic effective aperture under different fields of view meets the requirements of deep space links for received power, number of photons per bit, maximum communication rate, and mission data return volume.

[0083] S3: The target light spot is tracked by the tracking compensation component, and the tracking error is calculated by the optical receiving terminal. The tracking compensation component then compensates the optical receiving terminal based on the tracking error.

[0084] The process of calculating tracking error includes: Target optical signals of different wavelengths are incident on the photonic neural network of the optical receiving terminal; The target light signal of different wavelengths is diffracted and split by the diffraction grating in the photonic neural network to form multiple sub-beams; Multiple sub-beams are converged by a microlens array in a photonic neural network to a photodetector in the photonic neural network for photoelectric conversion, forming a detection pattern; The optical path difference between the two interfering sub-beams is extracted from the detection pattern, and then the optical path difference is converted into tracking error.

[0085] In this embodiment, λ1 represents the short-wavelength channel (800nm~860nm, typically 860nm) and λ2 represents the long-wavelength channel (1500nm~1550nm, typically 1550nm).

[0086] 1. Dual-wavelength spatial multiplexing interferometry modulation When two wavelengths propagate in different directions and have different spatial carrier frequencies after passing through a diffraction grating, the recombination intensity on the detection surface of the photodetector... It can be represented as: (31); Among them, A i B is the background intensity term. i To interfere with the adjustment mechanism, f i Let r be the spatial carrier frequency vector formed by the diffraction grating, off-axis angle, or channel design, and let r represent the two-dimensional spatial position coordinates on the detection surface of the photodetector, r=(x,y), where x and y correspond to the pixel positions on the detection surface of the photodetector in the horizontal and vertical directions, respectively. The phase corresponding to the wavefront to be measured. The active phase shift / modulation phase is optional. If the two wavelength channels fall on independent photodetectors, then equation (31) can be written in single-channel form with i=1 and 2 respectively.

[0087] 2. Single-wavelength phase demodulation For each wavelength channel, by selecting the corresponding carrier frequency sideband in the frequency domain and returning to the spatial domain, the complex analytic signal and enveloping phase of that wavelength can be obtained:

[0088] in, and These represent the Fourier transform and the inverse transform, respectively. Let represent the bandpass window function for the i-th wavelength channel. This represents the wrap-around phase value of the i-th wavelength channel at the detector pixel coordinates (x, y).

[0089] 3. Relationship between phase and optical path difference / piston difference After system zero-phase calibration, the measured phase of the i-th wavelength channel and the optical path difference W satisfy the following relationship: (33); in, W represents the wrap phase of the i-th wavelength channel; wrap(·) indicates that the phase is confined within a 2π period; Δh is the height difference between adjacent segmented mirror surfaces, and β is the incident angle of the normal to the segmented mirror surface. When incident near the normal, cosθ≈1, therefore W≈2Δh. This formula clarifies the integer wavelength order uncertainty in single-wavelength channel measurements.

[0090] 4. Synthetic wavelength and phase difference By differentially dividing the two wrapper phases, an equivalent synthetic wavelength channel can be constructed: (34); Wherein, Λ is the synthesized wavelength of the conventional dual-wavelength phase difference method, which is used to first obtain coarse measurement results with low sensitivity and large period, and then use the original single-wavelength phase to recover high-precision information.

[0091] 5. Coarse-level optical path difference / height difference demodulation For discrete height difference steps, instead of directly assuming that phase expansion can be completed through spatial continuity, an integer order P of the synthesized wavelength is explicitly introduced. Equation (35) generates a set of possible coarse-order optical path difference candidates, and then combines the system's physical range and dual-wavelength consistency to select a unique solution.

[0092] (35); in, This indicates candidate values ​​for coarse optical path difference measurement. This indicates the envelope phase corresponding to the synthesized wavelength. This represents the candidate values ​​for the coarse measurement of the height difference between the segmented mirror surfaces. Represents the set of integers.

[0093] 6. Dual-wavelength joint integer-order discrimination and fine reconstruction Within a finite search domain Ω defined by the segmented mirror actuator travel, initial calibration, geometric coarse measurement results, or candidate values ​​of Equation (35), select an integer-order array that best matches the optical path difference between the two wavelength channels. This step is responsible for truly eliminating single-wavelength 2π periodic ambiguity.

[0094]

[0095] in, This indicates that the i-th wavelength channel is in integer order. The estimated optical path difference is as follows; This represents the actual wavelength of the i-th wavelength channel; This represents the integer interference order of the i-th wavelength channel, or simply the integer order. Represents the optimal integer-order combination; This indicates finding the independent variable that minimizes the objective function within the parentheses.

[0096] After determining the integer order, the optical path difference estimates of the two wavelength channels can be weighted equally or by measurement variance and then fused to convert them into the optimal estimated height difference between two adjacent segmented mirror surfaces:

[0097] in, This represents the optimal optical path difference estimate after fusion; This represents the weighting coefficient of the i-th wavelength channel. This represents the optical path difference estimate of the i-th wavelength channel at the optimal integer order; This represents the measurement variance of the i-th wavelength channel; This represents the optimal estimated height difference between two adjacent segmented mirror surfaces; For sub-apertures spanning the edges of adjacent segmented mirrors, the optical path difference between the two interfering sub-beams is extracted based on their phase-sensitive patterns and converted into the height difference between the mirror surfaces of two adjacent segmented mirrors. For focal spots located within a single sub-aperture, the local wavefront slope or tilt is obtained based on the centroid shift. The processor demodulates the two wavelength channels to obtain the wrapping phase. and The composite phase is constructed from the two. and coarse-order optical path difference candidates By combining the actuator's stroke, initial position, or other prior measurement ranges to define the search interval for integer interferometric orders, the corresponding interferometric order is determined using a dual-wavelength phase consistency criterion. , Thus restoring the optimal optical path difference The optimal height difference between the adjacent segmented mirrors This allows for the formation of a coarse-to-fine combined detection chain: "dual-wavelength channel detection—single-wavelength phase demodulation—synthetic phase coarse measurement—integer-order joint discrimination—high-precision piston recovery." The calculation results are then used to control the segmented mirror actuator, the secondary mirror moving support mechanism, and the tracking compensation component, thereby improving the single-wavelength accuracy. Effective capture range and measurement reliability under phase ambiguity conditions.

[0098] S4: The processor controls the segmented mirror actuator, the secondary mirror moving support mechanism, and the tracking compensation component based on the tracking error.

[0099] The processor distributes control quantities to the segmented mirror actuator, the secondary mirror moving support mechanism, the focusing mechanism, and the fast-turning mirror according to the tracking error.

[0100] The segmented mirror actuator is used to adjust the pose of the segmented mirror to compensate for aberrations.

[0101] The secondary mirror moving support mechanism is used to adjust the position of the secondary mirror to adapt to different dynamic effective apertures of the optical splicing primary mirror.

[0102] The focusing mechanism is used to adjust the front and rear positions of the focusing lens group along the optical axis to achieve focusing of the optical receiving terminal, thereby compensating for focus deviation.

[0103] The quick-turn mirror is used to make small-angle corrections to the target optical signal to compensate for coupling deviation.

[0104] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0105] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A telescope optical receiving system, characterized in that, include: Optical splicing primary mirror, secondary mirror, tertiary mirror, optical receiving terminal, primary mirror support assembly, tracking compensation assembly, processor, dome support frame, secondary mirror moving support mechanism, and dome support truss; One end of the dome support truss is connected to the main mirror support assembly, and the other end of the dome support truss is connected to the dome load-bearing frame. The optical splicing primary mirror is mounted on the primary mirror support assembly. The optical splicing primary mirror adopts a primary mirror array composed of multiple segmented mirrors. Each segmented mirror is adjusted by an independent segmented mirror actuator. The secondary mirror is located in the reflection direction of the optical splicing primary mirror and is mounted on the secondary mirror moving support mechanism. The secondary mirror moving support mechanism is mounted on the dome support frame. The position of the secondary mirror relative to the optical splicing primary mirror is adjusted through the secondary mirror moving support mechanism. The three mirrors are located in the reflection direction of the secondary mirror and are set behind the optical splicing primary mirror; The optical receiving terminal is located in the reflection direction of the three mirrors and is used to receive the target light signal emitted by the target and reflected sequentially by the optical splicing primary mirror, secondary mirror and third mirror, and to calculate the tracking error; The tracking compensation component is used to track the target light spot and compensate the optical receiving terminal; The processor is used to control the segmented mirror actuator, the secondary mirror moving support mechanism, and the tracking compensation component based on the tracking error calculated by the optical receiving terminal.

2. The telescope optical receiving system according to claim 1, characterized in that, A light-passing aperture is formed in the central region of the primary mirror array. The target light signal reflected by the secondary mirror passes through this light-passing aperture and is then incident on the third mirror.

3. The telescope optical receiving system according to claim 1, characterized in that, The optical receiving terminal includes a focusing lens group, a narrowband filter, an optical fiber coupler, and a photonic neural network arranged sequentially along the propagation path of the target optical signal.

4. The telescope optical receiving system according to claim 3, characterized in that, The tracking compensation assembly includes a first beam splitter, a second beam splitter, a camera, a focal plane detector, a fast-steering mirror, and a focusing mechanism. The focusing mechanism is used to adjust the position of the focusing mirror group to achieve focusing of the optical receiving terminal. The first beam splitter is positioned between the narrowband filter and the fiber coupler. The camera is positioned in the reflected light path of the first beam splitter to capture and track the target light spot. The second beam splitter is positioned in the transmitted light path of the first beam splitter. The focal plane detector is positioned in the reflected light path of the second beam splitter to detect the focal plane of the target light spot. The fast-steering mirror is positioned in the transmitted light path of the second beam splitter, and the fiber coupler is positioned in the exit direction of the fast-steering mirror.

5. The telescope optical receiving system according to claim 4, characterized in that, The optical receiving terminal also includes a Hartmann wavefront sensing component and a third beam splitter. The third beam splitter is positioned between the second beam splitter and the fast-steering mirror. The Hartmann wavefront sensing component is positioned in the reflected light path of the third beam splitter and is used to measure the wavefront slope.

6. The telescope optical receiving system according to claim 3, characterized in that, The photonic neural network includes a diffraction grating, a microlens array, and a photodetector. The diffraction grating is used to diffract and split the target light signal output from the fiber coupler; the microlens array is used to converge the multiple sub-beams formed after the diffraction grating splits the light; and the photodetector is used to perform photoelectric conversion on the incident multiple beams.

7. A telescope optical receiving method, implemented using the telescope optical receiving system according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1: Track the target by using the optical splicing primary mirror, secondary mirror, tertiary mirror, and optical receiving terminal; S2: Determine the effective set of sub-apertures on the current optical splicing primary mirror used for tracking the target to form the target spot; S3: The target light spot is tracked by the tracking compensation component, and the tracking error is calculated by the optical receiving terminal. The tracking compensation component then compensates the optical receiving terminal based on the tracking error. The process of calculating the tracking error includes: Target optical signals of different wavelengths are incident on the photonic neural network of the optical receiving terminal; The target light signal of different wavelengths is diffracted and split by the diffraction grating in the photonic neural network to form multiple sub-beams; Multiple sub-beams are converged by a microlens array in a photonic neural network to a photodetector in the photonic neural network for photoelectric conversion, forming a detection pattern; The optical path difference between the two interfering sub-beams is extracted from the detection pattern, and then the optical path difference is converted into tracking error; S4: The processor controls the segmented mirror actuator, the secondary mirror moving support mechanism, and the tracking compensation component based on the tracking error.

8. The telescope optical receiving method according to claim 7, characterized in that, In step S2, the multiple segmented mirrors constituting the optical splicing primary mirror are divided into different sub-apertures, the effective weight of each sub-aperture is calculated, and sub-apertures that meet the conditions are selected according to the preset weight threshold. Let the first The geometric area of ​​each aperture is The sub-aperture at the current field of view and the current moment The effective weights are : ； in, Indicates the geometric illumination weights of the field of view. Indicates occlusion weight, Indicates the signal-to-noise ratio weight. Indicates wavefront stability weights. The value represents the contribution weight of fiber coupling, and E represents the total number of sub-apertures.

9. The telescope optical receiving method according to claim 7, characterized in that, In step S2, the stability of the effective sub-aperture set is evaluated using the Hartmann wavefront sensing component: Suppose that the Hartmann wavefront sensing assembly contains M sampling units, and measure the wavefront slope of each sampling unit: ； ； in, and This represents the wavefront slope of the i-th sampling unit in the X and Y directions; This indicates the focal length of the microlens inside the Hartmann wavefront sensing component; and This indicates the position of the reference spot in the i-th sampling unit; and This indicates the position of the light spot currently measured by the i-th sampling unit; and This represents the spot deviation of the i-th sampling unit in the X and Y directions; t represents the current time. The wavefront slopes of the M sampling units are combined to form a wavefront slope measurement vector; ； Calculating wavefront coefficients using wavefront slope measurement vectors : ； ， ； in, Represents the slope response matrix. Represents the regularization coefficient. Represents the dynamic weight matrix. Represents the identity matrix. Indicates matrix transpose; This represents the overall effective weight of the i-th sampling unit of the Hartmann wavefront sensing component; Represents a diagonal matrix; Based on wavefront coefficients Reconstructing the full-aperture wavefront error function : in, Indicates the first The basis functions of the Zernik polynomial, where K represents the total number of terms in the Zernik polynomial; Represents the normalized polar coordinates on the plane of the effective aperture of the optical splicing primary mirror; The center coordinates of the i-th sub-aperture in the effective sub-aperture set Substitute into the full-aperture wavefront error function obtained from reconstruction The reconstructed wavefront error at the i-th sub-aperture in the effective sub-aperture set is obtained. : ； Based on the reconstructed wavefront error at the i-th sub-aperture in the effective sub-aperture set Calculate the root mean square wavefront error within the current effective aperture of the optical splicing primary mirror. : in, This represents the effective sub-aperture weighted average wavefront error. This indicates the number of sub-apertures in the effective sub-aperture set; Based on the root mean square wavefront error within the current effective aperture of the optical splicing primary mirror The wavefront stability factor of the current effective aperture of the optical splicing primary mirror is calculated to evaluate the stability of the effective sub-aperture set. : in, Indicates the wavelength of the target optical signal.

10. The telescope optical receiving method according to claim 7, characterized in that, In step S4, the processor assigns control quantities to the segmented mirror actuator, the secondary mirror moving support mechanism, and the focusing mechanism and fast-turning mirror in the tracking compensation assembly according to the tracking error.

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