Digital sun sensor based on linear array CCD

Abstract

The invention discloses a digital sun sensor based on a linear array CCD (Charge Coupled Device), belongs to the technical field of sun tracking sensors, and aims to solve the problems of high hardware development difficulty, high hardware cost and high power consumption in the prior art. The device comprises an integral shell, and a protection window, a double-rectangular-opening diaphragm sheet, a neutral attenuation sheet, a linear array CCD module, a rotating motor and a main control board which are arranged in the integral shell, the main control board controls the rotating motor to drive the double-rectangular-opening diaphragm piece, the neutral attenuation piece and the linear array CCD module to rotate integrally. The linear array CCD module is electrically connected with the main control board; the double-rectangular-opening diaphragm is provided with two long-strip-shaped rectangular openings, and the long sides of the rectangular openings are perpendicular to the length direction of the linear array CCD module all the time. Sunlight is imaged on the linear array CCD module after sequentially passing through the protection window, the neutral attenuation sheet and the double-rectangular-opening diaphragm, and the main control board calculates the azimuth angle and the elevation angle of the sun according to the centers of images formed on the linear array CCD module at at least two different angles.

Description

Technical Field

[0001] The invention belongs to the technical field of sun tracking sensors, and in particular relates to a digital sun sensor based on a linear array CCD. Background Art

[0002] Atmospheric aerosols refer to tiny particles suspended in the atmosphere. Aerosols have an important impact on climate change, air quality, and human health. In order to qualitatively or quantitatively measure aerosols in the atmosphere, a device such as a sun photometer can be used to track and measure the sun, obtain the radiation brightness reaching the observation point in different solar bands, and then perform inversion calculations on the local atmospheric aerosols. Such devices for tracking and observing the sun need to accurately align the observation optical axis with the sun to achieve high-precision measurements. The sun sensor is an indispensable feedback device in the sun tracking device. The sun sensor can quantify the position of the sun in the sensor and output it in the form of an angle as a closed-loop feedback for the sun tracking device, so that the sun tracking turntable has real-time tracking capabilities.

[0003] At present, the common types of solar sensors are mainly divided into analog and digital types. The core component of the analog solar sensor is a four-quadrant silicon cell sensor. The pinhole imaging principle images the sun on the four photosensitive surfaces of the four-quadrant detector, and uses the current difference generated by the four photosensitive surfaces to calculate the deviation angle of the sun's position relative to the center of the four quadrants. The solar sensors disclosed in the Chinese patents with publication numbers CN115420282A and CN112432638B are all model solar sensors. The analog solar sensor was invented relatively early. Its principle is based on the different currents generated by the silicon photovoltaic cells in the four quadrants in response to the light signal of sunlight, thereby calculating the azimuth and altitude of the sun. Since the silicon photovoltaic cells in different quadrants of the four quadrants have different sensitivities to light signals, there are individual differences in the silicon photovoltaic cells in each quadrant during manufacturing, and the subsequent development circuit cannot be completely consistent. The center of the mechanical pinhole cannot be completely aligned with the center of the four quadrants. Therefore, the accuracy of the solar sensor based on the four quadrants is relatively low, and the analog solar sensor is gradually replaced by the digital solar sensor.

[0004] The digital sun sensor images the sun onto the photosensitive surface of the CCD array, and calculates the azimuth and altitude of the sun relative to the normal of the center pixel of the CCD array through the pixel deviation of the center of the image of the sun from the center of the CCD array. The technical solutions disclosed in the Chinese patents with publication numbers CN114760405B, CN107202583B, CN218765320U and CN116147570A are all digital sun sensors based on CCD array. At present, almost all digital sun sensors use CCD array as an imaging device to image the sun, and calculate the azimuth and altitude of the sun by calculating the pixel deviation of the position of the image of the sun in the CCD array from the center position through image processing algorithms. CCD array is generally developed using FPGA or high-end DSP, and the hardware development is difficult. With the increase of CCD array pixels, its hardware cost and power consumption will increase significantly, the single image processing time will also be correspondingly longer, and the power consumption of the entire system will also increase. When performing continuous sun tracking in seasons with higher temperatures, the heat dissipation of the array CCD will also cause a decline in system performance, or even overheating and malfunction. Summary of the invention

[0005] The purpose of the present invention is to provide a digital sun sensor based on a linear array CCD, so as to solve the problems of high difficulty in hardware development, high hardware cost and high power consumption in the prior art.

[0006] To achieve the above-mentioned purpose, the digital sun sensor based on linear array CCD of the present invention comprises an integral housing, and a protective window, a double rectangular aperture diaphragm, a neutral attenuation sheet, a linear array CCD module, a rotating motor and a main control board which are sequentially arranged inside the integral housing along the axis direction of the integral housing; the main control board controls the rotating motor to drive the double rectangular aperture diaphragm, the neutral attenuation sheet and the linear array CCD module to rotate as a whole; the linear array CCD module is electrically connected to the main control board;

[0007] The protection window is sealed and connected to the overall housing to seal the interior;

[0008] The double rectangular opening aperture plate is provided with two long rectangular openings, and the long sides of the rectangular openings are always perpendicular to the length direction of the linear array CCD module;

[0009] Sunlight enters the overall housing through the protective window and is attenuated by the neutral attenuation sheet. It is imaged on the linear array CCD module after passing through the double rectangular aperture sheet. The main control board calculates the azimuth and altitude of the sun based on the center of the image formed on the linear array CCD module at at least two different angles.

[0010] The digital sun sensor also includes:

[0011] A support seat is arranged in the integral housing, and the double rectangular opening aperture plate and the neutral attenuation plate are mounted on the support seat through a pressing ring;

[0012] A linear array CCD mounting seat is arranged in the overall housing, the linear array CCD module is mounted on the linear array CCD mounting seat, the support seat and the linear array CCD mounting seat are connected as a whole by screws; the support seat and the linear array CCD mounting seat are integrally mounted on the rotor at the upper part of the rotating motor;

[0013] And a fixing seat, the fixing seat is fixedly mounted on the inner step surface of the integral shell, and the stator at the lower part of the rotating motor is mounted on the fixing seat.

[0014] The digital sun sensor also includes:

[0015] An electric slip ring, wherein the rotating part of the electric slip ring is mounted on the linear array CCD mounting seat, the fixed part of the electric slip ring is connected to the stator of the rotating motor, and the fixed part of the electric slip ring is electrically connected to the main control board;

[0016] And an external socket, which is arranged in the overall shell and has one end passing through the side wall of the overall shell. The data line and the power supply line of the main control board are connected to the outside world through the external socket.

[0017] The digital sun sensor also includes:

[0018] A window gland detachably connected to the upper end surface of the integral housing by bolts, the protection window is compressed and sealed by the window gland, and an outer sealing ring is provided between the window gland and the step surface of the integral housing;

[0019] An inner sealing ring is provided between the upper end of the protection window and the contact surface of the window gland and between the lower end of the protection window and the step surface of the overall shell;

[0020] And a bottom cover detachably connected to the lower end surface of the integral shell through bolts, and a radial sealing ring is arranged between the bottom cover and the contact surface of the integral shell.

[0021] The protection window is a neutral attenuation filter with a transmittance of 1%, and the material is quartz glass.

[0022] The neutral attenuation plate is made of quartz glass with a transmittance of 0.1%.

[0023] The outer sealing ring and the inner sealing ring are O-type sealing rings, and the material is fluororubber.

[0024] The beneficial effects of the present invention are as follows: the digital solar sensor based on linear array CCD of the present invention utilizes a rotating motor to drive the linear array CCD module to rotate, and the angular difference of the sun's position relative to the solar sensor can be calculated by measuring at two angles, and data collection and processing can be completed using a single-chip microcomputer. The linear array CCD has only one column of data, which greatly reduces the difficulty of data processing. Compared with the digital solar sensor of the planar array CCD, the development difficulty, cost, power consumption, etc. are significantly reduced; two neutral density attenuation plates consisting of a protective window and a neutral attenuation plate are used to achieve attenuation of direct sunlight, which can prevent the detector from being over-saturated on the one hand, and can isolate most of the ambient light interference on the other hand, thereby improving safety and detection accuracy; the rotating motor is integrated with a conductive slip ring, which can avoid winding problems during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is an overall structural appearance diagram of the digital sun sensor based on linear array CCD of the present invention;

[0026] Figure 2 A cross-sectional view of the structure of a digital sun sensor based on a linear array CCD of the present invention;

[0027] Figure 3 This is a structural diagram of the internal rotating part of the digital sun sensor based on the linear array CCD of the present invention after removing the overall shell;

[0028] Figure 4 It is a partial cross-sectional view of the structure of the internal rotating part of the digital sun sensor based on the linear array CCD of the present invention after removing the overall shell;

[0029] Figure 5 The structure and size diagram of the double rectangular aperture diaphragm in the digital sun sensor based on linear array CCD of the present invention;

[0030] Figure 6 A diagram showing the distance between the linear array CCD and the double rectangular aperture diaphragm in the digital sun sensor based on the linear array CCD of the present invention;

[0031] Figure 7 Schematic diagram of parameters of a digital sun sensor based on a linear array CCD of the present invention;

[0032] Figure 8 It is the measured original image when the sun is in the field of view of the sun sensor;

[0033] Fig. 9 For Figure 8 The smoothed image after the original image is smoothed;

[0034] Fig.10 For Fig. 9 The binary image after the smoothed image is binarized;

[0035] Including: 1. outer sealing ring, 2. window pressure cover, 3. protection window, 4. overall shell, 5. linear array CCD module, 501, linear array CCD photosensitive surface, 6. linear array CCD mounting seat, 7. rotating motor, 701, stator, 702, rotor, 8. external socket, 9. bottom cover, 10. radial sealing ring, 11. main control board, 12. fixed seat, 13. electric slip ring, 14. support seat, 15. double rectangular opening aperture plate, 16. neutral attenuation plate, 17. pressure ring, 18. inner sealing ring. DETAILED DESCRIPTION

[0036] The embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

[0037] The main application area of ​​solar sensors is to serve as feedback devices for solar tracking turntables to assist them in achieving accurate pointing toward the sun. Since the position of the sun changes relatively slowly when tracking the sun on the earth, solar sensors for tracking the sun on the earth do not require a very high data update rate, and more consideration should be given to issues such as accuracy and power consumption.

[0038] In order to balance factors such as solar angle measurement accuracy, development difficulty and power consumption, the present invention selects a linear array CCD as a photosensitive device, uses an optimized double rectangular opening as a system aperture, effectively utilizes the characteristics of the slow change of the solar angle, designs a rotary motor 7 with an electric slip ring 13 to drive the linear array CCD module 5 to rotate, measures the solar angle at different rotary motor 7 angles, and uses at least two positions to calculate the solar azimuth and altitude information, and can use data from multiple angles for fitting, thereby improving the measurement accuracy. At the same time, since the number of pixels of the linear array CCD is much smaller than that of the area array CCD, the development difficulty is significantly reduced, and a low-cost single-chip microcomputer can be used for development. The hardware composition is simpler than that of the area array CCD, and the linear array CCD can be designed with a model with multiple pixel numbers and large pixel sizes, thereby further improving the field of view and accuracy of the digital solar sensor based on the linear array CCD.

[0039] See also Figure 1-Figure 4 The digital sun sensor based on linear array CCD of the present invention comprises:

[0040] The overall housing 4 and the protective window 3, the double rectangular aperture diaphragm 15, the neutral attenuation plate 16, the linear array CCD module 5, the rotating motor 7 and the main control board 11 which are sequentially arranged inside the overall housing 4 along the axis direction of the overall housing 4; the main control board 11 controls the rotating motor 7 to drive the double rectangular aperture diaphragm 15, the neutral attenuation plate 16 and the linear array CCD module 5 to rotate as a whole; the linear array CCD module 5 and the main control board 11 are electrically connected;

[0041] The protection window 3 is sealed and connected to the overall housing 4 to seal the interior;

[0042] The double rectangular aperture diaphragm 15 is provided with two long rectangular openings, and the long sides of the rectangular openings are always perpendicular to the length direction of the linear array CCD module 5;

[0043] The sunlight enters the overall housing 4 through the protective window 3 and is attenuated by the neutral attenuation plate 16. After passing through the double rectangular aperture plate 15, it is imaged on the linear array CCD module 5. The main control board 11 calculates the azimuth and altitude of the sun based on the center of the image formed on the linear array CCD module 5 at at least two different angles.

[0044] The digital sun sensor also includes:

[0045] A support seat 14 is arranged in the integral housing 4, and the double rectangular aperture diaphragm piece 15 and the neutral attenuation piece 16 are mounted on the support seat 14 through a pressing ring 17;

[0046] A linear array CCD mounting seat 6 is arranged in the overall housing 4, the linear array CCD module 5 is mounted on the linear array CCD mounting seat 6, the support seat 14 and the linear array CCD mounting seat 6 are connected as a whole by screws; the support seat 14 and the linear array CCD mounting seat 6 are integrally mounted on the rotor 702 at the upper part of the rotating motor 7;

[0047] And a fixing seat 12 , the fixing seat 12 is fixedly mounted on the inner step surface of the integral housing 4 , and the stator 701 at the lower part of the rotating motor 7 is mounted on the fixing seat 12 .

[0048] The digital sun sensor also includes:

[0049] An electric slip ring 13, wherein the rotating part of the electric slip ring 13 is mounted on the linear array CCD mounting seat 6, the fixed part of the electric slip ring 13 is connected to the stator 701 of the rotating motor 7, and the fixed part of the electric slip ring 13 is electrically connected to the main control board 11;

[0050] And an external socket 8, which is arranged in the overall shell 4, and one end of which passes through the side wall of the overall shell 4. The data line and the power line of the main control board 11 are connected to the outside world through the external socket 8.

[0051] The double rectangular aperture aperture piece 15 and the neutral attenuation piece 16 of the present invention are installed on the support seat 14 through the pressing ring 17, and the rotating parts of the linear array CCD module 5 and the electric slip ring 13 are installed on the linear array CCD mounting seat 6. After the support seat 14 and the linear array CCD mounting seat 6 are connected by screws, they are installed on the rotor 702 of the rotating motor 7 as a whole. The rotating motor 7 is an outer rotor 702 motor, and the upper surface is the rotor 702 part, which can rotate along the center line. The lower surface of the rotating motor 7 is the stator 701, which is installed on the fixed seat 12. The fixed seat 12 is installed on the inner step surface of the overall housing 4 with screws; the rotating motor 7 has an integrated absolute encoder, and the current rotation speed of the rotating motor 7 can be queried through the data communication interface. angle information; the fixed part of the electric slip ring 13 is connected to the stator 701 of the rotating rotary motor 7. When the rotating motor 7 rotates, the main control board 11 and the linear array CCD module 5 can realize bidirectional transmission of electrical signals through the inner and outer ring cables of the electric slip ring 13. The electrical signals include power supply and digital signals; the bottom cover 9 is fully sealed with the overall housing 4 through the radial sealing ring 10, so as to prevent dust and water vapor from entering the overall housing 4; the data line and the power line of the main control board 11 are connected to the outside through the external socket 8, and the digital sun sensor can be powered and communicated with data through the external socket 8; the external socket 8 is a six-core plug with a protection level of IP67, which can be used for a long time in an outdoor environment when a docking plug is inserted.

[0052] The digital sun sensor also includes:

[0053] A window gland 2 detachably connected to the upper end surface of the integral housing 4 by bolts, through which the protection window 3 is compressed and sealed, and an outer sealing ring 1 is provided between the window gland 2 and the step surface of the integral housing 4;

[0054] An inner sealing ring 18 is provided between the contact surface between the upper end of the protection window 3 and the window gland 2 and between the lower end of the protection window 3 and the step surface of the integral housing 4, thereby achieving sealing of the digital sun sensor and preventing dust and water vapor from entering the interior of the integral housing;

[0055] And a bottom cover 9 detachably connected to the lower end surface of the integral housing 4 through bolts, and a radial sealing ring 10 is arranged between the contact surface of the bottom cover 9 and the integral housing 4.

[0056] The protection window 3 is a neutral attenuation filter with a transmittance of 1%, and the material is quartz glass.

[0057] The neutral attenuation plate 16 is made of quartz glass with a transmittance of 0.1%.

[0058] The outer sealing ring 1 and the inner sealing ring 18 are O-type sealing rings, and the material is fluororubber.

[0059] The overall housing 4 is the installation housing of the entire assembly, and all optical parts and electronic devices are installed inside it.

[0060] The digital sun sensor based on linear array CCD avoids the problems of large data volume, complex processing algorithm, high power consumption and excessive heat dissipation caused by using area array CCD as a photosensitive device. The data of linear array CCD can be read and quickly processed using a conventional single-chip microcomputer.

[0061] The digital sun sensor involved in the present invention is based on the linear array CCD rotating around the rotating motor 7, and measures the center of the image formed by the sun passing through the double rectangular aperture diaphragm 15 on the linear array CCD module 5 at different angles, thereby calculating the azimuth and altitude angle of the sun. In this embodiment, the CCD model on the linear array CCD module 5 used is Toshiba TCD1304DG, the pixel of the CCD is 8μm, and the number of pixels is 3648. The STC32G12K128 single-chip microcomputer on the main control board 11 can read the pixel grayscale value of the linear array CCD module 5, and process the read column of data to calculate the angle value of the current sun position relative to the center of the ready-made CCD module. Driven by the rotating motor 7, the sun angle information of at least two angles can be measured to obtain the relative angle of the sun, and the measurement accuracy can be achieved that is equivalent to that of the digital sun sensor based on the area array CCD of 3648×3648 pixels. Compared with the area array CCD based on the same parameters, the solar sensor based on the linear array CCD (TCD1304) needs to calculate one frame of data at two angles to obtain solar angle data once, that is, the processing of 2×3648=7296 pixel data, while the solar sensor based on the area array CCD needs to process 3648×3648=13307904 pixel data. It can be seen that the solar sensor based on the linear array CCD has obvious computing advantages.

[0062] The light intensity of sunlight reaching the linear array CCD module 5 after passing through the protective window 3, the neutral attenuation sheet 16 and the double rectangular aperture diaphragm sheet 15 is 0.00001 (1%*0.1%=0.00001) of the original light intensity. The protective window 3 and the neutral attenuation sheet 16 form a two-stage attenuation. After the two-stage attenuation, on the one hand, it can ensure that direct sunlight will not cause excessive saturation of the pixels of the linear array CCD to damage the CCD device, and on the other hand, it can filter non-direct sunlight light so that the impact of these stray lights on the system is close to the background noise of the linear array CCD, which is convenient for setting data thresholds and reducing the difficulty of data processing. In the absence of direct sunlight, the effective light intensity on the linear array CCD is very low, and the output grayscale value is close to 0; because the ambient light is very weak compared to the direct sunlight, this solution can effectively shield the influence of ambient light and ensure that effective solar angle information can only be analyzed when the sun is directly shining.

[0063] The double-rectangular opening diaphragm 15 of the present invention has two long-strip rectangular openings. The long sides of the rectangular openings are always perpendicular to the length direction of the linear array CCD module 5. This installation method can ensure that no matter at what angle the sun irradiates the double-rectangular opening diaphragm 15, two illuminated areas will always be detected on the linear array CCD module 5. The double-rectangular opening diaphragm 15, the retaining ring 17, the support base 14, and the linear array CCD module 5 are all installed on the rotor 702 of the rotating motor 7. When the sun is within the field of view of the sun sensor, the rotor 702 of the rotating motor 7 rotates, driving all the parts installed thereon to rotate. If the sun's position is on the axis of the rotating motor 7, no matter what angle the rotating motor 7 rotates to, the positions of the two bright strips formed by the double-rectangular opening diaphragm 15 on the linear array CCD module 5 remain unchanged. If the sun's position is not on the axis of the rotating motor 7, when the rotating motor 7 rotates by a certain angle, the positions of the two bright strips formed by the double-rectangular opening diaphragm 15 on the linear array CCD module 5 will change. The angle of the sun's position relative to the sun sensor can be calculated through this position change amount.

[0064] The linear array CCD module 5 is composed of a linear array CCD sensor, a CCD pixel readout circuit, and a single-chip microcomputer control circuit. According to different degrees of light sensitivity, the pixels of the linear array CCD are sequentially converted into voltage signals through the CCD pixel readout circuit, and are stored as digital signals after AD acquisition by the single-chip microcomputer control circuit. The main control board 11 can communicate with the above single-chip microcomputer control circuit through a serial port to read each frame of data.

[0065] The linear array CCD module 5 is connected to the main control board 11 through a wire. To ensure that the connection line between the two does not get wound when the rotating motor 7 rotates, resulting in jamming of the rotating motor 7, the wire of the linear array CCD module 5 is connected to the inner ring wire harness of the conductive slip ring 13, and the corresponding outer ring wire harness of the conductive slip ring 13 is connected to the corresponding wiring terminal of the main control board 11. The inner ring and the outer ring of the conductive slip ring 13 can rotate relative to each other without affecting the electrical connection of the inner and outer wire harnesses. Therefore, it can be ensured that when the rotating motor 7 rotates, the power supply and communication electrical signals between the linear array CCD module 5 and the main control board 11 are uninterrupted.

[0066] See Figure 7 , the formula (1) for calculating the instantaneous half field of view angle θ of the sun sensor of the present invention is:

[0067] θ = arctan((L - l) / (2d)) (1)

[0068] Where: L is the length of the effective photosensitive surface of the linear array CCD module 5. In this embodiment, the pixel size is 8μm and the number of pixels is 3,648. Therefore, L = 29.184mm;

[0069] l is the width of the opening of the double rectangular aperture diaphragm 15. In this embodiment, the aperture size is as shown in Figure 5 , the aperture width is l = 4mm;

[0070] d is the distance between the double rectangular aperture diaphragm 15 and the linear array CCD photosensitive surface 501, see Figure 6 , in this embodiment, d = 32 mm;

[0071] Substituting the above data into formula (1), it can be calculated that the instantaneous half field angle θ=21.48°, and the average angular resolution corresponding to each pixel is 21.48° / (3648 / 2)=0.012°.

[0072] Figure 5 In the double rectangular opening aperture plate 15, the distance a between the two rectangular openings is 1 mm, the width b of each rectangular opening is 1.5 mm, and the length c of each rectangular opening is 18 mm; the aperture width l = b+a+b.

[0073] If the sun is not in the field of view of the sensor, due to the effect of the two-stage low-transmittance attenuation film composed of the protection window 3 and the neutral attenuation film 16, the light signal received by the linear array CCD module 5 is close to 0, so the readout data of the detector at this time are close to the background noise, and there is no obvious peak signal; if the sun is in the field of view of the sensor, due to the existence of the double rectangular aperture diaphragm film 15, the two rectangular apertures of the double rectangular aperture diaphragm film 15 will be projected on the linear array CCD module 5. At this time, the signal of the linear array CCD module 5 will show two columns of data with peak signals. The typical original image is as follows Figure 8 As shown; the original measured original image is smoothed to obtain a smoothed image, as shown Fig. 9 As shown; then the smoothed image is binarized to obtain a binary image as shown Fig.10 As shown in the figure, the average value of the pixels corresponding to the first falling edge and the second rising edge in the obtained curve is the imaging position of the sun on the linear array CCD at the current measurement angle. Figure 7-Figure 9 Taking the measurement results shown as an example, the current sun imaging position is 1192 pixels; taking the middle position 1824 pixels of the linear array CCD as the center position of the sun sensor, the deflection angle of the sun relative to the center field of view of the sun sensor can be calculated as (1192-1824)*0.012°=-7.584°.

[0074] Before the sun sensor works, the motor is calibrated to make the length direction of the linear array CCD in a horizontal state at 0 degrees. If the sun is in the field of view of the sun sensor, when the sun sensor works, the rotating motor 7 is first rotated to 0 degrees, that is, the sun sensor is rotated to the 0 degree position, and the angle of the sun relative to the central field of view of the sun sensor, that is, the azimuth angle is measured as θ1. Then, the rotating motor 7 is rotated to 90 degrees, that is, the sun sensor is rotated to the 90 degree position, and the angle of the sun relative to the central field of view of the sun sensor, that is, the altitude angle is measured as θ2. It can be seen that the azimuth angle and altitude angle deviation of the sun's position relative to the central field of view of the sun sensor can be calculated by measuring two orthogonal angles.

[0075] Furthermore, in order to eliminate the fact that the central field of view of the sun sensor does not pass through the central pixel 1824 of the linear array CCD, during measurement, the rotating motor 7 can be rotated to 0 degrees to measure the solar azimuth angle θ0 at this time, and then the rotating motor 7 can be rotated to 180 degrees to measure the solar azimuth angle θ 180 , take the final relative azimuth angle as θ1 = (θ0-θ 180 ) / 2; Similarly, the rotating motor 7 is rotated to 90 degrees, and the solar altitude angle θ is measured at this time 90 Then rotate the rotating motor 7 to 270 degrees and measure the solar azimuth angle θ at this time. 270 , take the final relative altitude angle as θ2=(θ 90 -θ 270 ) / 2; The four-time measurement method can improve the measurement accuracy while doubling the measurement time. Since the movement of the sun is a very slow process, the total time of the four measurements does not exceed 0.5S, and the data reading and processing of the four-time linear array CCD is still very small compared with the data processing of the 3648×3648 pixel array CCD. Therefore, this solution can effectively improve the measurement accuracy without significantly reducing the efficiency.

Claims

1. A digital sun sensor based on a linear CCD array, comprising an integral housing (4), characterized in that: It also comprises a protective window (3), a double rectangular aperture diaphragm (15), a neutral attenuation plate (16), a linear array CCD module (5), a rotating motor (7) and a main control board (11) which are sequentially arranged inside the overall housing (4) along the axis direction of the overall housing (4); the main control board (11) controls the rotating motor (7) to drive the double rectangular aperture diaphragm (15), the neutral attenuation plate (16) and the linear array CCD module (5) to rotate as a whole; the linear array CCD module (5) and the main control board (11) are electrically connected; The protection window (3) is sealedly connected to the overall housing (4) to seal the interior; The double rectangular opening aperture plate (15) is provided with two long rectangular openings, and the long sides of the rectangular openings are always perpendicular to the length direction of the linear array CCD module (5); Sunlight enters the overall housing (4) through the protective window (3) and is attenuated by a neutral attenuation sheet (16). After passing through a double rectangular aperture sheet (15), an image is formed on a linear array CCD module (5). The main control board (11) calculates the azimuth and altitude of the sun based on the center of the image formed on the linear array CCD module (5) at at least two different angles.

2. The linear array CCD-based digital sun sensor according to claim 1, characterized in that: The digital sun sensor also includes: A support seat (14) is arranged in the integral housing (4), and the double rectangular opening aperture plate (15) and the neutral attenuation plate (16) are mounted on the support seat (14) via a pressing ring (17); A linear array CCD mounting seat (6) is arranged in the overall housing (4), the linear array CCD module (5) is mounted on the linear array CCD mounting seat (6), the support seat (14) and the linear array CCD mounting seat (6) are connected as a whole by screws; the support seat (14) and the linear array CCD mounting seat (6) are integrally mounted on a rotor (702) at the upper part of the rotating motor (7); and a fixing seat (12), wherein the fixing seat (12) is fixedly mounted on the inner step surface of the integral housing (4), and the stator (701) at the lower part of the rotating motor (7) is mounted on the fixing seat (12).

3. The linear array CCD-based digital sun sensor according to claim 2, characterized in that: The digital sun sensor also includes: An electric slip ring (13), wherein a rotating part of the electric slip ring (13) is mounted on the linear array CCD mounting seat (6), a fixed part of the electric slip ring (13) is connected to a stator (701) of a rotating motor (7), and the fixed part of the electric slip ring (13) is electrically connected to the main control board (11); and an external socket (8), wherein the external socket (8) is arranged in the overall shell (4) and one end thereof passes through the side wall of the overall shell (4); the data line and the power supply line of the main control board (11) are connected to the outside world through the external socket (8).

4. The digital sun sensor based on linear array CCD according to any one of claims 1 to 3, characterized in that: The digital sun sensor also includes: A window pressure cover (2) detachably connected to the upper end surface of the integral housing (4) by means of bolts, the protection window (3) is compressed and sealed by the window pressure cover, and an outer sealing ring (1) is provided between the step surface of the window pressure cover (2) and the integral housing (4); An inner sealing ring (18) is provided between the upper end of the protection window (3) and the contact surface of the window gland (2) and between the lower end of the protection window (3) and the step surface of the integral housing (4); and a bottom cover (9) detachably connected to the lower end surface of the integral housing (4) via bolts, wherein a radial sealing ring (10) is provided between the contact surfaces of the bottom cover (9) and the integral housing (4).

5. The digital sun sensor based on linear CCD according to any one of claims 1 to 3, characterized in that: The protection window (3) is a neutral attenuation filter with a transmittance of 1%, and the material is quartz glass.

6. The digital sun sensor based on linear CCD according to any one of claims 1 to 3, characterized in that: The neutral attenuation plate (16) is made of quartz glass with a transmittance of 0.1%.

7. The digital sun sensor based on linear CCD according to any one of claims 1 to 3, characterized in that: The outer sealing ring (1) and the inner sealing ring (18) are O-type sealing rings, and the material is fluororubber.

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