Large-view-field sun sensor for spacecraft and method

Abstract

The invention discloses a large-view-field sun sensor for a spacecraft and a method, and relates to the technical field of light detection. The large-view-field sun sensor comprises a polyhedral base and a plurality of light intensity detection units, the polyhedral base is provided with a plurality of detection surfaces arranged on the side edge of the polyhedral base, and each detection surface is obliquely arranged in the same direction of the polyhedral base and is distributed in a convex divergent shape; the light intensity detection unit is arranged on the detection surface, and the light intensity detection unit is configured to output a light intensity signal in proportion to the effective coverage area of sunlight on the light sensing surface of the light intensity detection unit. The projection areas of the polyhedral base and the light intensity detection unit are used for detecting light intensity signals, a wide-angle lens system needed by a traditional imaging type sensor is replaced, the problems of optical distortion and non-uniform energy distribution of a wide-angle lens in an edge view field are solved, the view field is greatly expanded, and meanwhile the light intensity of the wide-angle lens is greatly improved. And high-precision measurement in a view field range is also ensured.

Description

Technical Field

[0001] This application relates to the field of light detection technology, and in particular to a large field-of-view solar sensor and method for spacecraft. Background Technology

[0002] The sun sensor is a key component of the spacecraft's attitude control and navigation subsystem. It primarily determines the direction of the solar vector by measuring the angle of incidence of sunlight relative to the spacecraft's coordinate system. Using the sun as a reference target, with its small apparent radius, high illumination intensity, and definite relative position, the sun sensor is widely used in attitude measurement and attitude acquisition missions for various satellites, spacecraft, and other spacecraft.

[0003] In existing solar sensors, digital solar sensors that typically employ imaging principles typically have a front-end optical system composed mainly of pinholes, slits, or lens groups, while the back-end area array photodetector is mainly composed of CCD or CMOS image sensors. A signal processing circuit is also built in addition. The working principle is that sunlight is projected onto the photosensitive surface of the area array detector through the front-end optical system to form a light spot or a specific image. After the readout circuit acquires the image data, the digital processor runs a centroid extraction or geometric calculation algorithm to determine the angle of incidence of the sun based on the position coordinates of the light spot in the pixel array.

[0004] However, existing technologies have the following shortcomings in practical applications: Current detection technologies employ a combination of a front-end optical system and a rear-end area array photodetector. Limited by the geometric characteristics of planar imaging devices and the aperture constraints of the front-end optical system, their effective measurement field of view is typically confined to within ±60°, making it difficult to achieve hemispherical spatial coverage. To pursue a larger field of view, current technologies have resorted to introducing wide-angle or fisheye lens systems. However, this forced expansion of the field of view introduces severe optical distortion problems. As the incident angle increases, the light spot projected onto the detector's edge region exhibits significant morphological distortion and uneven energy distribution. These optical characteristics, including morphological distortion and uneven energy distribution, undermine the assumptions of the centroid extraction algorithm, leading to a substantial decrease in the accuracy of angle calculations at the field of view edges. This makes it impossible to meet the requirement of high-precision measurement across the entire spatial domain without blind spots, while ensuring high-precision measurement across the entire field of view.

[0005] Therefore, this application aims to solve the technical problem that existing imaging solar sensors are limited by planar imaging geometry and cannot simultaneously achieve large field-of-view coverage and edge measurement accuracy. Summary of the Invention

[0006] The main objective of this application is to provide a large field-of-view solar sensor and method for spacecraft, which aims to solve the problem that the field of view of existing solar sensors is limited and cannot improve the accuracy of edge measurement.

[0007] To achieve the above objectives, this application proposes a large field-of-view solar sensor for spacecraft, comprising a polyhedral base, wherein the polyhedral base includes: Multiple detection surfaces are provided on the side of the polyhedral base, and each detection surface is inclined in the same direction on the polyhedral base. Multiple light intensity detection units are disposed on multiple detection surfaces; the light intensity detection units are configured to output light intensity signals that are proportional to the effective coverage area of ​​sunlight on the light intensity detection unit.

[0008] This application utilizes a vertical plane and a detection surface surrounding the vertical plane, with an obtuse angle between the vertical plane and the detection surface, to form a convex polyhedral base structure. Combined with the effective coverage area of ​​the light intensity detection unit, this structure replaces the wide-angle lens system required by traditional imaging sensors. The diverging structure of the polyhedral base ensures unobstructed structural views within a hemispherical field of view of ±90° or even larger. By using the linear relationship of geometric projection area to replace lens imaging, it eliminates the optical distortion and uneven energy distribution problems present in wide-angle lenses at the edge of the field of view. This significantly expands the field of view while ensuring high-precision measurements within the entire field of view.

[0009] Furthermore, the polyhedral base also includes a vertical surface; Multiple detection surfaces are arranged around the edge of the vertical plane, and each detection surface makes an obtuse angle with the vertical plane; The light intensity detection unit is also disposed on the vertical surface.

[0010] Furthermore, the vertical plane is a regular polygonal plane, and multiple detection surfaces are correspondingly connected to the edges of the vertical plane.

[0011] Furthermore, the number of detection surfaces is three or more, and the three or more detection surfaces are evenly distributed circumferentially along the vertical plane.

[0012] Furthermore, it also includes a filter unit, which is connected to the vertical surface and the corresponding detection surface of the polyhedral base and covers the photosensitive path of the light intensity detection unit.

[0013] Furthermore, the filter unit is a quartz glass cover plate, and an attenuation film is coated on the surface of the quartz glass cover plate.

[0014] This application attenuates high-intensity solar radiation in the space environment to the optimal linear response range of the light intensity detection unit, such as 20-100 times attenuation. This not only avoids device saturation damage but also filters out thermal noise interference in the ultraviolet and infrared bands, further improving the signal-to-noise ratio.

[0015] Furthermore, the light intensity detection unit includes a first detection unit and multiple second detection units. The first detection unit is attached to the vertical surface; Multiple second detection units are respectively attached to the corresponding detection surfaces.

[0016] Furthermore, the interior of the polyhedral base is provided with multiple independent mounting cavities, and each light intensity detection unit is placed in a corresponding mounting cavity; A light-blocking element is provided between the multiple independent mounting cavities to block reflected light from different mounting cavities.

[0017] By setting independent mounting cavities and light-blocking components inside the polyhedral base, optical isolation of each channel is achieved, effectively blocking diffuse reflection and scattering crosstalk of light inside, ensuring that each light intensity detection unit only responds to the direct incident light within its field of view, and improving the stability of the light intensity detection signal.

[0018] This application also discloses a measurement method for a solar sensor, including the following steps: Acquire light intensity detection units located on vertical surfaces and multiple detection surfaces at different preset angles, and acquire multiple light intensity detection signals respectively; The multiple light intensity detection signals are filtered to determine the effective measurement channels that are within the linear operating range; Based on the preset spatial angle relationship of the light intensity detection unit on the polyhedral base, the solar vector is calculated by combining the light intensity detection signals of the effective measurement channel.

[0019] Furthermore, the calculation of the solar vector using the combined light intensity detection signals from the effective measurement channel includes: Select at least two light intensity detection units on the detection surface as solution pairs; Using the ratio of the difference to the sum of the light intensity detection signals from the two light intensity detection units in the solution pair, a functional analytical model of the solar incidence component angle is established. Based on the analytical model of the function, the projection component angles of sunlight in different projection planes of the polyhedral base are calculated, and the solar vector is synthesized.

[0020] In the above-mentioned process of acquiring light intensity detection signals, the solar illuminance is first obtained through the detection unit, and the light signal is converted into solar illuminance data. Secondly, the amplification unit is preferably an amplifier, which linearly amplifies the weak illuminance data to make its amplitude suitable for subsequent circuits. Furthermore, the analog-to-digital conversion unit converts the amplified analog signal into a high-precision digital signal and stores it in an internal register. Finally, the solar sensor control unit is selected as an MCU, and the MCU obtains the digital signal through the analog-to-digital conversion unit corresponding to the detection surface. This digital signal is the light intensity detection signal described below. The MCU calculates the solar vector by combining multiple light intensity detection signals. Attached Figure Description

[0021] The present application will now be described in detail with reference to specific embodiments and accompanying drawings, wherein: Figure 1 This is a schematic diagram showing the position and structure of the sun relative to this application; Figure 2 This is a structural diagram of one embodiment of the present application; Figure 3 This is a structural diagram of another embodiment of this application; Figure 4 This is a schematic diagram of the lighting structure of this application; Figure 5 This is a cross-sectional structural diagram of this application; Figure 6 This is a schematic diagram of the coordinate distribution structure of this application; Figure 7 This is a spectral diagram of the light intensity detection unit of this application; Figure 8 This is a schematic diagram of the structure of this application and the sun in a three-dimensional coordinate system; Figure 9 This is a diagram showing the photosensitive range and linearity of the light intensity detection unit in this application; Figure 10 This is a flowchart of the method in this application; Figure 11 This is a flowchart of step S3 in this application; Figure 12 This is a schematic diagram of the satellite data acquisition and execution structure for this application; Figure 13 This is a flowchart of the satellite angle correction process for this application; Figure 14 This is a structural block diagram of the satellite light intensity detection signal acquisition in this application.

[0022] In the diagram: 100, vertical plane; 200, detection surface; 300, filter unit; 400, light intensity detection unit; 401, first detection unit; 402, second detection unit; 500, light-blocking component. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the following specific embodiments are merely illustrative of this application and do not constitute a limitation thereof.

[0024] Sun sensors are among the most widely used optical sensors in spacecraft attitude determination and control systems. As a standard component of spacecraft attitude control systems, satellites, being part of the overall spacecraft architecture, typically have two or more sun sensors on a single satellite. These sensors detect the orientation of the sun's vector within the celestial coordinate system, thereby calculating the spacecraft's attitude information relative to the sun.

[0025] The angular radius of the apparent disk of the sun is extremely small and almost independent of satellite orbits. In most applications, sunlight can be approximated as a parallel light source, such as... Figure 1 It can be seen that this simplifies the geometric model for attitude calculation. Due to the high intensity of solar radiation in the space environment, the optical system and detection circuit structure of the sensor are relatively simple and have extremely low power consumption.

[0026] Currently, existing solar sensors cover a wide range of fields of view (FOV) from a few arcminutes to 128°*128°, and their measurement resolution can also cover different accuracy levels from a few degrees to a few arcseconds.

[0027] Based on their working principle and signal output form, solar sensors are mainly divided into the following three categories: (1) Analog sun sensor: Its output signal is a continuous analog function of the celestial body's azimuth relative to the sun vector (i.e., the sun angle), which is usually used for coarse attitude acquisition; (2) 0-1 type solar sensor or solar appearance sensor: its output signal is a binary digital signal, i.e. 0 or 1, which is only used to characterize whether the sun is within the sensor's field of view. It is often used for system protection or mode switching. (3) Digital sun sensor: It can provide discrete coded output signals, and its output value is a function of the measured solar angle. Digital sun sensors have significant advantages such as large field of view, high precision, long life and high reliability, and are the mainstream choice for high-performance satellites.

[0028] Digital sun sensors calculate the angle of sunlight incidence by determining the relative positional deviation of incident sunlight rays on the target surface of a photodetector. Based on the different photosensitive elements, they are mainly divided into charge-coupled device (CCD) type and complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) type.

[0029] In the technical background involved in this embodiment, the field of view of a typical digital sun sensor is usually around ±60°, and its measurement accuracy can be better than 0.05°.

[0030] In existing high-precision solar sensor technologies, a combination of a front-end optical system and a back-end area array photodetector is typically employed. However, those skilled in the art have discovered in practical engineering that, due to the geometric characteristics of planar imaging devices and the aperture limitations of the front-end optical system, wide-angle lenses must be introduced to expand the field of view. However, wide-angle lenses produce severe distortion at the edges of the field of view, leading to uneven energy distribution of the light spot and thus compromising the accuracy of the centroid algorithm. Furthermore, direct illumination of the imaging device by intense light (1367 W / m²) in the space environment easily causes pixel saturation.

[0031] Therefore, this application proposes a structure that does not use the existing front-end optical system and back-end area array photodetector. Instead, it utilizes the combination of polyhedral geometry and light intensity detection unit 400 to improve the field of view without introducing a wide-angle lens, and at the same time, completes the high-precision measurement requirements under the premise of a large field of view.

[0032] like Figures 2 to 4 As shown, this embodiment discloses a large field-of-view solar sensor for spacecraft, including a polyhedral base. The polyhedral base includes multiple detection surfaces 200 and multiple light intensity detection units 400. The multiple detection surfaces 200 are disposed on the side of the polyhedral base, and each detection surface 200 is inclined in the same direction on the polyhedral base. Multiple light intensity detection units 400 are disposed on multiple detection surfaces 200; the light intensity detection unit 400 is configured to output a light intensity signal that is proportional to the effective coverage area of ​​sunlight on the light intensity detection unit 400.

[0033] The core component of the large field-of-view solar sensor is a polyhedral base. Specifically, the polyhedral base is designed as a convex geometry with multiple detection surfaces 200. Each detection surface 200 is tilted in the same direction on the polyhedral base. A light intensity detection unit 400 is then installed on each detection surface 200. When sunlight shines on the sensor, the subsequent analytical model of the function can be generated through the light intensity detection unit 400 on each detection surface 200, thereby synthesizing the solar vector.

[0034] In this embodiment, the polyhedral base preferably has a vertical surface 100 at the top, and multiple detection surfaces 200 are arranged around the edge of the vertical surface 100. The vertical surface 100 and the detection surfaces 200 can be features inherent to the polyhedral base itself, such as through cutting, grinding, polishing, etc., ultimately resulting in the vertical surface 100 and multiple detection surfaces 200 on the polyhedral base. Alternatively, multiple planar plates can be separately installed on the polyhedral base, with the planar plates respectively installed at the top and sides of the polyhedral base, thereby forming a vertical surface 100 and multiple detection surfaces 200. In this embodiment, the vertical surface 100 can be located at the top or bottom of the polyhedral base, and its specific location is not limited.

[0035] Light intensity detection units 400 are provided on both the vertical surface 100 and the detection surface 200. The light intensity detection unit 400 on the vertical surface 100 serves as the main photosensitive carrier, with the largest area exposed to sunlight, thus serving as the main judgment benchmark. The detection surface 200 is distributed around the vertical surface 100, and the light intensity detection units 400 on it have varying areas exposed to sunlight, thus serving as judgment objects. By comparing the light intensity detection units 400 on multiple detection surfaces 200, the solar vector can be obtained.

[0036] In this embodiment, the angle between each detection surface 200 and the vertical surface 100 is an obtuse angle, that is, a range greater than 90 degrees and less than 180 degrees. In practical applications, it is recommended that the obtuse angle be designed between 110° and 150°, preferably 135°. The obtuse angle design makes the multiple detection surfaces 200 distributed in a divergent manner relative to the vertical surface 100, which can ensure that when sunlight is incident from the side and rear, even if the incident angle reaches ±90° or even greater, the light can still shine vertically or nearly vertically onto a certain detection surface 200 without being blocked by the structure of the base itself, thereby achieving hemispherical or even super-hemispherical field of view coverage.

[0037] Light intensity detection units 400 are respectively installed on the vertical surface 100 and each detection surface 200. One or more light intensity detection units 400 can be set on each detection surface 200 and the vertical surface 100 to improve the accuracy of data acquisition. Preferably, only one light intensity detection unit 400 is set on each detection surface 200 and the vertical surface 100 in this application. The light intensity detection unit 400 in this embodiment differs from a CCD or CMOS image sensor; it does not perform image acquisition but operates based on the effective coverage area. That is, the electrical signal (such as current or voltage) output by the light intensity detection unit 400 is linearly proportional to the projected area of ​​sunlight illuminating its photosensitive surface, such as... Figure 4 As can be seen from the cosine law, when parallel light rays are incident at an angle... When light shines on a plane, the amount of light it receives Where E represents the solar illuminance in lux (lx), and S is the photosensitive area of ​​the light intensity detection unit 400. This embodiment utilizes the output signal of the light intensity detection unit 400 and... The corresponding relationship is used to perform subsequent angle calculations, avoiding the introduction of nonlinear optical distortion caused by wide-angle lenses.

[0038] like Figures 2 to 4 As shown, the vertical plane 100 is a regular polygonal plane, and multiple detection surfaces 200 are connected to the edges of the vertical plane 100. The number of detection surfaces 200 is equal to the number of sides of the regular polygon, and they are connected one-to-one to each edge of the vertical plane 100, forming a regular frustum structure. The entire frustum structure is symmetrically designed, which helps to eliminate systematic deviations caused by manufacturing errors and provides the same measurement accuracy at all azimuth angles.

[0039] like Figures 2 to 4 As shown, in this embodiment, in order to ensure the symmetry of the solution algorithm and simplify the coordinate transformation matrix, the vertical plane 100 is designed as a regular polygonal plane, such as a square or a regular hexagon. When the vertical plane 100 is a quadrilateral plane, the number of detection surfaces 200 is four. The four detection surfaces 200 are evenly distributed along the circumference of the vertical plane 100, and the normal directions of two opposite detection surfaces 200 are opposite to each other.

[0040] like Figure 2 and Figure 6 It can be seen that, Figure 6 The diagram shows a top view of the polyhedral base, with coordinate axes labeled on it. Using the origin O, the X-axis, and the Y-axis as the positive directions (as indicated by the arrows), the directions are defined as +X, -X, +Y, and -Y. The vertical surface 100 is specifically designed as a square plane. Correspondingly, there are four detection surfaces 200: a first side (corresponding to the +X direction), a second side (corresponding to the -X direction), a third side (corresponding to the +Y direction), and a fourth side (corresponding to the -Y direction). These four detection surfaces 200 are evenly distributed around the circumference of the vertical surface 100, forming a regular square truncated pyramid structure. The normal directions of opposite detection surfaces 200 (e.g., the +X and -X surfaces) are opposite in spatial projection, conforming to the Cartesian coordinate system commonly used in satellite attitude control. In subsequent signal processing, differential calculations can be performed using the opposite light intensity detection units 400 to maximize the cancellation of common-mode interference.

[0041] like Figure 3 As shown, the vertical plane 100 is a hexagonal plane, and there are six detection surfaces 200, which are evenly distributed along the circumference of the vertical plane 100.

[0042] As another embodiment of this application, the vertical plane 100 can also be designed as a hexagonal plane, with six corresponding detection surfaces 200, distributed at 60-degree intervals. Compared to a quadrangular truncated pyramid, the hexagonal truncated pyramid structure increases the number of light intensity detection units 400, significantly improving the azimuth measurement resolution and reducing the blind transition zone between adjacent sensors, making it suitable for deep space exploration missions requiring higher smoothness of full celestial coverage. When the number of detection surfaces 200 is three or more, preferably four or six, the computational difficulty is reduced. When the number of detection surfaces 200 exceeds three, redundancy of the light intensity detection units 400 is increased. If some light intensity detection units 400 are damaged, the solar vector can be directly obtained by simply removing the equations corresponding to the damaged light intensity detection units 400.

[0043] like Figure 2 and Figure 3 As shown, this application also includes a filter unit 300, which is connected to the vertical surface 100 of the polyhedral base and the corresponding detection surface 200, and covers the photosensitive path of the light intensity detection unit 400.

[0044] To address the strong light saturation problem mentioned in this application, this embodiment also introduces a filter unit 300. The filter unit 300 is connected not only to the vertical surface 100 but also to each detection surface 200, and it tightly covers the front of the photosensitive path of each light intensity detection unit 400. This means that sunlight must pass through the filter unit 300 before reaching the photosensitive surface of any light intensity detection unit 400, ensuring that the light intensity detection unit 400 will not be saturated or damaged due to direct exposure to strong radiation.

[0045] In this application, the filter unit 300 can be directly attached to the vertical surface 100 or the side of the detection surface 200 located in outer space, or it can be attached to the side facing away from outer space. The specific choice can be made according to the needs. For the above-mentioned planar plate solution, the filter unit 300 can be directly attached to the planar plate, which makes the replacement efficiency of the filter unit 300 and the planar plate higher.

[0046] The filter unit 300 is a quartz glass cover plate, and an attenuation film is coated on the surface of the quartz glass cover plate. In this embodiment, the filter unit 300 preferably uses an optical-grade quartz glass cover plate, because it has radiation resistance and thermal stability, and an attenuation film is coated on the inner or outer surface of the quartz glass.

[0047] Specifically, the attenuation film system is a neutral density filter film with an optical density (OD value) designed between 1.3 and 2.0, which attenuates the transmitted light intensity to 1 / 20 to 1 / 100 of the incident light intensity. This reduces the intensity of sunlight in space, which was originally as high as 130,000 lx, to within the linear operating range (e.g., 0-5000 lx) of the light intensity detection unit 400, thus ensuring linearity. Furthermore, the attenuation film system may also include a cutoff band to filter out ultraviolet wavelengths below 400 nm and infrared wavelengths above 1100 nm, preventing thermal noise interference with the response of the silicon-based detector. After passing through the filtering unit 300, Figure 7 The graph shows the intensity detection unit 400, which is mainly capable of detecting wavelengths from 400nm to 760nm.

[0048] like Figure 4 and Figure 5 As shown, the light intensity detection unit 400 includes a first detection unit 401 and a plurality of second detection units 402. The first detection unit 401 is attached to the vertical surface 100; the plurality of second detection units 402 are respectively attached to the corresponding detection surfaces 200.

[0049] The first detection unit 401, serving as the main reference sensor, is directly mounted on the geometric center of the vertical surface 100 using surface mount technology (SMT) or conductive adhesive bonding. Multiple second detection units 402 are respectively mounted on the center lines of each detection surface 200. This embodiment preferably employs an integrated design, allowing the light intensity detection unit 400 to be directly soldered onto the circuit board on the polyhedral surface or onto the polyhedral base itself. This eliminates the complex lens alignment process found in traditional optical heads, significantly improving vibration resistance.

[0050] like Figure 5 As shown, the polyhedral base has multiple independent mounting cavities inside, and each light intensity detection unit 400 is housed in its corresponding mounting cavity; light-blocking components 500 are arranged between the multiple independent mounting cavities to block the reflected light from different mounting cavities.

[0051] To further improve measurement accuracy and prevent stray light interference, the polyhedral base has multiple independent mounting cavities, with each light intensity detection unit 400 isolated within its own cavity. Light-blocking elements 500 are installed between adjacent cavities to separate the light intensity detection units 400. These light-blocking elements 500 can be formed from the base's built-in reinforcing ribs, inserted black anodized aluminum plates, or the corresponding mounting cavities can be machined from within the polyhedral base.

[0052] The surface of the light-blocking component 500 in this embodiment has undergone a matte finish treatment, such as spraying light-absorbing black paint, to block light from being reflected or scattered from one mounting cavity to another. This ensures that each light intensity detection unit 400 only responds to direct incident light from its corresponding normal direction field of view, guarantees the purity of the cosine law corresponding to each light intensity detection unit 400, and eliminates measurement noise caused by multipath reflection.

[0053] like Figure 14 As shown, to obtain solar illuminance data, it is necessary to collect and process the illuminance data. Specifically, in the above-mentioned process of acquiring light intensity detection signals, the solar illuminance is first obtained through the detection unit, and the light signal is converted into solar illuminance data. Secondly, the amplification unit is preferably an amplifier, which linearly amplifies the weak illuminance data to make its amplitude suitable for subsequent circuits. Furthermore, the analog-to-digital conversion unit converts the amplified analog signal into a high-precision digital signal and stores it in an internal register. Finally, the solar sensor control unit is selected as an MCU, and the MCU obtains the digital signal through the analog-to-digital conversion unit corresponding to the detection surface. This digital signal is the light intensity detection signal described below. The MCU calculates the solar vector by combining multiple light intensity detection signals.

[0054] like Figure 10 As shown, this embodiment also discloses a measurement method for a solar sensor, including the following steps: Step S1: Obtain light intensity detection units 400 located on vertical surfaces 100 and multiple detection surfaces 200 at different preset angles, and obtain multiple light intensity detection signals respectively; Step S2: Filter the multiple light intensity detection signals to determine the effective measurement channels within the linear operating range; Step S3: Based on the preset spatial angle relationship of the light intensity detection unit 400 on the polyhedral base, the solar vector is calculated by combining the light intensity detection signals of the effective measurement channel.

[0055] The measurement method in this embodiment first performs a data acquisition step. The system controller (such as an FPGA or MCU) concurrently acquires the analog voltage or current signals of all light intensity detection units 400 located on the vertical plane 100 and each detection surface 200 through multiple ADC channels, and converts them into digital quantities. Next, step S2 is executed. Due to the structure of the polyhedral base, the side facing away from the sun is inevitably in shadow, and its output signal is only dark current or noise. The system compares the acquired signal with a preset effective threshold. Only signals greater than the effective threshold but not yet saturated are marked as valid measurement channels and then proceed to subsequent calculation steps. In step S2, the selected signals need to be pre-screened. The specific screening scheme is as follows: Figure 9It is known that the signal from the 400 light intensity detection unit is unstable, with fluctuations observed at 10 lx and 100,000 lx. Therefore, pre-screening requires comparing a more stable signal segment with the effective threshold. Specifically, this can be achieved by selecting... Figure 9 For signals with moderate illumination between 100 lx and 10000 lx, the segment of the signal to be extracted can be selected according to the waveform; there are no specific limitations here.

[0056] Finally, step S3 is executed: based on the preset spatial angle relationship between the effective measurement channel and the light intensity detection unit 400 on the polyhedral base, the preset spatial angle relationship is the initial corresponding position relationship, such as the pre-calibrated angle, normal vector, etc., step S3 combines these effective signals to invert the solar vector.

[0057] like Figure 11 As shown, in step S3, the calculation of the solar vector using the combined light intensity detection signals from the effective measurement channel includes: Step S31: Select at least two light intensity detection units 400 on the detection surface 200 as a solution pair; Step S32: By calculating the ratio of the difference to the sum of the light intensity detection signals of the two light intensity detection units 400, a functional analytical model of the solar incidence component angle is established. Step S33: Calculate the projection component angles of sunlight on different projection surfaces of the polyhedral base based on the function analytical model, and synthesize them to obtain the solar vector.

[0058] This is the core step of this application: the system preferentially selects valid signals from two opposing detection surfaces 200 (e.g., the +X surface and the -X surface) as a solution pair. Subsequently, using the signals from this solution pair, the ratio of the difference to the sum is constructed.

[0059] like Figure 4 and Figure 8 As shown, step S31, based on the polyhedral frustum structure of this application, defines the following parameters: The preset detection surface tilt angle is 200°, which is the angle between the side normal and the vertical plane normal Z-axis at 100°. For example... or .

[0060] The angle of incidence of parallel light or sunlight on a vertical plane at 100°, such as Figure 4 It can be known that...

[0061] : The angle of incidence of the projection of sunlight onto the XZ plane (to be determined).

[0062] : The angle of incidence of the projection of sunlight onto the YZ plane (to be determined).

[0063] : Maximum solar intensity under current conditions (unknown and fluctuating).

[0064] : The current of the first detection unit 401 under the current environment.

[0065] Based on Lambert's cosine law and geometric projection relationships, we can determine the parameters... , The theoretical output currents of A and B, a pair of light intensity detection units 400 located opposite each other in the X-axis direction (+X direction and -X direction), are calculated as follows: ; ; ; ; ; Step S32: Constructing the difference and sum model to solve for the angle. The system first performs difference and sum operations on the two signals, using trigonometric function sum-to-product formulas: Difference operation:

[0066] ; Sum operation:

[0067] ; Step S33 involves ratio elimination and calculation, dividing the above difference by the sum to construct the ratio: ; In this step, uncertainties exist simultaneously in both the numerator and denominator. and coupling terms It was automatically canceled out.

[0068] The formula simplifies to: ; Therefore, the projection angle along the X-axis can be obtained directly. The analytical formula is: ; ; Similarly, for a pair of detection units (+Y plane and -Y plane) in the Y-axis direction, the projection angle in the Y-axis direction can be solved using the same derivation logic. : In the formula The changes are automatically eliminated during the division process. This means that regardless of whether the sun's light intensity changes due to distance variations, or whether the overall sensitivity of the light intensity detection unit 400 drifts due to temperature variations, as long as the changing trends of the pair of light intensity detection units 400 are consistent, the final calculated angle will remain the same. All of these are unaffected, which greatly improves the system's robustness in harsh space environments and its long-term on-orbit accuracy. Finally, by synthesizing the component angles of the XZ and YZ planes, the complete three-dimensional solar vector can be obtained.

[0069] like Figure 12 and Figure 13 As shown, this application acquires multiple light intensity detection signals through a first detection unit 401 and multiple second detection units 402, and sends the multiple light intensity detection signals to the solar sensor control unit. Subsequently, the solar sensor control unit processes the multiple light intensity detection signals in steps S2 and S3 to generate a three-dimensional solar vector, and sends the three-dimensional solar vector to the satellite mission control unit. The satellite mission control unit then generates an adjustment command based on the three-dimensional solar vector and its own attitude, and sends the adjustment command to the attitude execution unit to complete the final satellite attitude adjustment.

[0070] like Figure 12 and Figure 13 The detailed execution process is as follows: In its initial state, the satellite needs to activate the light intensity detection unit 400, i.e., powering on the light intensity detection unit 400 via the circuit board. Subsequently, the light intensity detection unit 400 collects multiple light intensity detection signals according to step S1 described above. After receiving these signals, the solar sensor control unit internally processes them using preset logic to determine if the signals are normal. Specifically, it checks if each light intensity detection signal exceeds a valid threshold. If it does, the data is considered normal; if it does, it is considered abnormal data, possibly indicating a malfunction of the light intensity detection unit 400 at that location, and the data needs to be discarded. Then, the solar sensor control unit... The sensor control unit uses the remaining multi-channel light intensity detection signals to calculate the angle between the satellite and the sun, and sends the angle to the satellite mission control unit. After receiving the signal, the satellite mission control unit will also internally determine the deviation value and send adjustment commands to the attitude execution unit. The attitude execution unit will adjust the satellite's angle based on the adjustment commands and finally determine whether the angle is perpendicular to the sun to obtain the maximum charging efficiency. If it is perpendicular, it will be in a charging state and will continuously collect and judge data after a delay. If the satellite is not perpendicular to the sun, it will immediately collect and judge data, and then continuously adjust the angle of the satellite.

[0071] The above description is merely a preferred embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the inventive concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A large field-of-view solar sensor for spacecraft, characterized in that, Includes a polyhedral base, the polyhedral base comprising: Multiple detection surfaces are provided on the side of the polyhedral base, and each detection surface is inclined in the same direction on the polyhedral base. Multiple light intensity detection units are disposed on multiple detection surfaces; the light intensity detection units are configured to output light intensity signals that are proportional to the effective coverage area of ​​sunlight on the light intensity detection unit.

2. The large field-of-view solar sensor for spacecraft as described in claim 1, characterized in that, The polyhedral base also includes a vertical surface; Multiple detection surfaces are arranged around the edge of the vertical plane, and each detection surface makes an obtuse angle with the vertical plane; The light intensity detection unit is also disposed on the vertical surface.

3. The large field-of-view solar sensor for spacecraft as described in claim 2, characterized in that, The vertical plane is a regular polygonal plane, and multiple detection surfaces are connected to the edges of the vertical plane.

4. The large field-of-view solar sensor for spacecraft as described in claim 2, characterized in that, The number of detection surfaces is three or more, and the three or more detection surfaces are evenly distributed circumferentially along the vertical plane.

5. The spacecraft large field-of-view solar sensor as described in any one of claims 2 to 4, characterized in that, It also includes a filter unit, which is connected to the vertical surface and the corresponding detection surface of the polyhedral base and covers the photosensitive path of the light intensity detection unit.

6. The large field-of-view solar sensor for spacecraft as described in claim 5, characterized in that, The filter unit is a quartz glass cover plate, and an attenuation film is coated on the surface of the quartz glass cover plate.

7. The large field-of-view solar sensor for spacecraft as described in claim 2, characterized in that, The light intensity detection unit includes a first detection unit and multiple second detection units. The first detection unit is attached to the vertical surface; Multiple second detection units are respectively attached to the corresponding detection surfaces.

8. The large field-of-view solar sensor for spacecraft as described in claim 1, characterized in that, The polyhedral base has multiple independent mounting cavities inside, and each light intensity detection unit is respectively housed in the corresponding mounting cavity. A light-blocking element is provided between the multiple independent mounting cavities to block reflected light from different mounting cavities.

9. A measurement method based on the solar sensor according to any one of claims 1 to 8, characterized in that, Includes the following steps: Acquire light intensity detection units located on vertical surfaces and multiple detection surfaces at different preset angles, and acquire multiple light intensity detection signals respectively; The multiple light intensity detection signals are filtered to determine the effective measurement channels that are within the linear operating range; Based on the preset spatial angle relationship of the light intensity detection unit on the polyhedral base, the solar vector is calculated by combining the light intensity detection signals of the effective measurement channel.

10. The measurement method of the solar sensor as described in claim 9, characterized in that, The calculation of the solar vector using the combined light intensity detection signals from the effective measurement channel includes: Select at least two light intensity detection units on the detection surface as solution pairs; Using the ratio of the difference to the sum of the light intensity detection signals from the two light intensity detection units in the solution pair, a functional analytical model of the solar incidence component angle is established. Based on the analytical model of the function, the projection component angles of sunlight in different projection planes of the polyhedral base are calculated, and the solar vector is synthesized.

Images