Large dynamic star sensor integrated with high-precision MEMS gyroscope and working method of large dynamic star sensor

Abstract

The invention discloses a large dynamic star sensor integrated with a high-precision MEMS gyroscope and a working method of the large dynamic star sensor, and belongs to the technical field of star sensors. In order to provide a large dynamic star sensor integrated with high-precision MEMS gyroscopes, the large dynamic star sensor comprises a star sensor, an MEMS gyroscope combination is mounted on a base of the star sensor, the MEMS gyroscope combination comprises a main body structure and three single-axis MEMS gyroscopes, the three single-axis MEMS gyroscopes are mounted on the front side face, the left side face and the upper side face of the main body structure, and the three single-axis MEMS gyroscopes are mounted on the front side face, the left side face and the upper side face of the main body structure. And the mounting directions of the three single-axis MEMS gyroscopes are respectively overlapped with three coordinate axes of a star sensor coordinate system. According to the invention, advantage complementation of the star sensor and the gyroscope is realized in the product, and the precision and the stability are improved; data fusion processing is realized in the star sensor, dependence on external auxiliary equipment is reduced by an integrated product, data interaction and processing are realized in the product, and autonomy is enhanced; the response speed and flexibility are improved; the product size is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of star sensors, and in particular relates to a large dynamic star sensor integrated with a high-precision MEMS gyroscope and a working method thereof. Background Art

[0002] Star sensors are key components of high-precision spacecraft. They are mainly used to measure the components of star vectors in the star sensor coordinate system, and determine the three-axis attitude of the spacecraft relative to the inertial coordinate system by identifying star maps and using the precise positions of known stars. They have the advantages of high positioning accuracy, small mass, low power consumption, high autonomy, and no cumulative attitude error. They are currently the most accurate of all attitude sensors.

[0003] The gyroscope can continuously and in real time measure the angular velocity of the satellite, has high short-term stability, and can provide instant information on the satellite's dynamic motion. However, over time, the gyroscope will accumulate drift errors, resulting in a decrease in long-term accuracy.

[0004] Traditional star sensors are susceptible to strong vibration and high-speed rotation under high-dynamic flight conditions, such as rapid satellite orbit changes or the ascent phase of a launch vehicle, which makes star pattern recognition difficult and reduces positioning accuracy. Although existing technologies have attempted to reduce these effects through complex algorithms and external auxiliary equipment, they have not yet fully solved the performance bottleneck under a large dynamic range. Therefore, there is an urgent need for a star sensor design that can directly integrate high-precision attitude sensing elements and enhance anti-interference capabilities.

[0005] Currently, satellite platforms often use a star sensor + gyroscope combination attitude determination solution, but star sensors and gyroscopes are independent products, and there is no product that integrates star sensors and gyroscopes. Summary of the invention

[0006] The problem to be solved by the present invention is to provide a large dynamic star sensor integrated with a high-precision MEMS gyroscope, and propose a large dynamic star sensor integrated with a high-precision MEMS gyroscope and a working method thereof.

[0007] To achieve the above object, the present invention is implemented through the following technical solutions:

[0008] A large dynamic star sensor integrated with high-precision MEMS gyroscopes comprises a star sensor, a base of the star sensor is provided with a MEMS gyroscope assembly, the MEMS gyroscope assembly comprises a main body structure and three single-axis MEMS gyroscopes, the three single-axis MEMS gyroscopes are installed on the front side surface, the left side surface and the upper side surface of the main body structure, and the installation directions of the three single-axis MEMS gyroscopes respectively coincide with the three coordinate axes of the star sensor coordinate system.

[0009] Furthermore, the deviation between the measurement axis of each single-axis MEMS gyroscope and the coordinate axis of the corresponding star sensor is less than 0.05°.

[0010] Furthermore, based on the accurate angular rate information collected by the MEMS gyro combination, the star sensor achieves precise attitude prediction and processing.

[0011] Furthermore, the star sensor and each single-axis MEMS gyroscope use independent SPI communication lines for data exchange. The star sensor uses FPGA to implement the SPI interface with the single-axis MEMS gyroscope, collects data from the three single-axis MEMS gyroscopes in parallel, and sends the data to the CPU in the star sensor for data processing.

[0012] Furthermore, the installation and adjustment process of the single-axis MEMS gyroscope is as follows: after the single-axis MEMS gyroscope is welded to the flexible printed circuit board, the bottom surface of the gyroscope ceramic tube shell of the single-axis MEMS gyroscope is bonded to the installation plane of the main structure; first, the bonding ensures that the bottom surface of the gyroscope ceramic tube shell is parallel to the installation surface of the main structure, and then the transfer matrix of the MEMS gyroscope combination relative to the optical axis of the star sensor is calibrated through a high-precision turntable, the relative position relationship between the MEMS gyroscope combination and the star sensor is confirmed, and the installation of the single-axis MEMS gyroscope is fine-tuned until the installation accuracy requirements are met.

[0013] A working method of a large dynamic star sensor integrated with a high-precision MEMS gyroscope is implemented based on the large dynamic star sensor integrated with a high-precision MEMS gyroscope, and includes the following steps:

[0014] S1. The MEMS gyro combination measures the angular rate information on the three axes of the star sensor body coordinate system, and uses the SPI interface to transmit the collected angular rate information on the three axes to the star sensor;

[0015] S2. Based on the angular rate information on the three axes obtained in step S1, the star sensor accurately predicts the attitude, identifies and matches the star map, and calculates the attitude. The predicted attitude and the measured attitude are then fused to obtain the final output attitude information and angular rate information.

[0016] Furthermore, in step S1, x is set st ,y st 、z st are the x-axis coordinate, y-axis coordinate, and z-axis coordinate of the star sensor, me ,y me 、z me are the x-axis coordinate, y-axis coordinate, and z-axis coordinate of the MEMS gyroscope combination.

[0017] Furthermore, the specific implementation method of data fusion of the predicted posture and the measured posture in step S2 includes the following steps:

[0018] S2.1. Set the angular rate estimate measured by the MEMS gyro assembly The expression is:

[0019]

[0020] Among them, ω g,k is the angular rate output by the MEMS gyro combination at the kth frame, are the estimated angular rates of the kth frame of the MEMS gyroscope combination on the x-axis, y-axis, and z-axis, respectively. is the estimated value of the k-th frame constant drift of the MEMS gyro assembly;

[0021] S2.2. Predict the attitude of the next measurement cycle based on the estimated angular rate measured by the MEMS gyro combination obtained in step S2.1, expressed as:

[0022]

[0023] Among them, Q k is the k-th frame pose, Q k+1 / k is the predicted k+1th frame posture, T is the data update period, λ is the rotation angle within a period, ω x，k+1 is the x-axis angular rate output by the MEMS gyro combination in the k+1th frame, ω y, k+1 is the y-axis angular rate output by the MEMS gyro combination in the k+1th frame, ω z, k+1 is the z-axis angular rate output by the MEMS gyro combination in the k+1th frame;

[0024]

[0025] S2.3. Set the state quantity to where q e is the error quaternion, δd is the gyro drift error;

[0026] S2.4. Set the initial value of the state variable X0 = 0 6*1 , initial value of state covariance P0 = 1*10 -10 I 6*6 , gyro constant drift initial value Perform state prediction, measurement update and state correction, and integrate to obtain the updated state quantity, which is expressed as:

[0027]

[0028] Among them, X k+1 is the state quantity of the k+1th frame, q e,k+1 is the error quaternion of the k+1th frame, δd k+1 is the zero bias error of the k+1th frame;

[0029] The estimated attitude and gyro drift are then corrected;

[0030]

[0031] Where Q k+1 is the posture of the k+1th frame, is the estimated value of the k+1th frame constant drift of the MEMS gyro combination.

[0032] Furthermore, in view of the impact of temperature changes on the performance of the MEMS gyroscope combination and the star sensor optical components, aluminum-based silicon carbide is selected to make the mechanical structure of the star sensor and the mechanical structure of the MEMS gyroscope combination, and a semiconductor cooler and a PID control method based on pulse width modulation are used to control the cooler, thereby achieving high-precision temperature control of the mounting surface and ensuring that the star sensor maintains stable working performance in different temperature domains.

[0033] Beneficial effects of the present invention:

[0034] In the large dynamic star sensor integrated with high-precision MEMS gyroscope described in the present invention, data fusion processing is implemented in the star sensor, and no additional hardware equipment is needed to respectively receive data from the star sensor and the MEMS gyroscope and then perform data fusion.

[0035] The large dynamic star sensor integrated with a high-precision MEMS gyroscope described in the present invention realizes complementary advantages of the star sensor and the gyroscope within the product through the integration of the star sensor and the MEMS gyroscope, thereby improving the precision and stability.

[0036] The large dynamic star sensor integrated with a high-precision MEMS gyroscope described in the present invention reduces the dependence on external auxiliary equipment in the integrated product, realizes data interaction and processing within the product, and enhances autonomy.

[0037] The invention discloses a large dynamic star sensor with integrated high-precision MEMS gyroscope. The integrated product can quickly respond to attitude changes through an internally optimized data processing algorithm, thereby improving response speed and flexibility.

[0038] The large dynamic star sensor integrated with a high-precision MEMS gyroscope described in the present invention reduces product volume, weight and power consumption, and realizes miniaturization and low-cost design of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of a large dynamic star sensor integrated with a high-precision MEMS gyroscope according to the present invention;

[0040] Figure 2 A three-dimensional diagram of a large dynamic star sensor with integrated high-precision MEMS gyroscope according to the present invention;

[0041] Figure 3 It is a flow chart of a working method of a large dynamic star sensor integrated with a high-precision MEMS gyroscope according to the present invention;

[0042] Figure 4 Internal data flow diagram of the large dynamic star sensor integrated with high-precision MEMS gyroscope of the present invention DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the specific embodiments described are only part of the embodiments of the present invention, rather than all of the specific embodiments. The components of the specific embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations, and the present invention can also have other embodiments.

[0044] Therefore, the following detailed description of the specific embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected specific embodiments of the present invention. Based on the specific embodiments of the present invention, all other specific embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0045] In order to further understand the content, features and effects of the present invention, the following specific implementation methods are given as examples, and the attached Figure 1 -Attached Figure 4 The detailed instructions are as follows:

[0046] Embodiment 1:

[0047] A large dynamic star sensor integrated with high-precision MEMS gyroscopes comprises a star sensor 1. A MEMS gyroscope assembly is installed on the base of the star sensor 1. The MEMS gyroscope assembly comprises a main structure 4 and three single-axis MEMS gyroscopes 5. The three single-axis MEMS gyroscopes 5 are installed on the front side, left side and upper side of the main structure 4. The installation directions of the three single-axis MEMS gyroscopes 5 respectively coincide with the three coordinate axes of the coordinate system of the star sensor 1.

[0048] Furthermore, the deviation between the measurement axis of each single-axis MEMS gyroscope 5 and the coordinate axis of the corresponding star sensor 1 is less than 0.05°.

[0049] Furthermore, based on the accurate angular rate information collected by the MEMS gyro combination, the star sensor achieves precise attitude prediction and processing.

[0050] Furthermore, the star sensor 1 and each single-axis MEMS gyroscope 5 use an independent SPI communication line 3 for data exchange. The star sensor 1 uses FPGA to implement the SPI interface with the single-axis MEMS gyroscope 5, collects data from the three single-axis MEMS gyroscopes 5 in parallel, and sends the data to the CPU in the star sensor 1 for data processing. Figure 4 shown.

[0051] Furthermore, the installation and adjustment process of the single-axis MEMS gyroscope 5 is as follows: after the single-axis MEMS gyroscope 5 is welded to the flexible printed circuit board, the bottom surface of the gyroscope ceramic shell of the single-axis MEMS gyroscope 5 is bonded to the installation plane of the main structure 4; first, the bonding ensures that the bottom surface of the gyroscope ceramic shell is parallel to the installation surface of the main structure 4, and then the transfer matrix of the MEMS gyroscope combination relative to the optical axis of the star sensor 1 is calibrated through a high-precision turntable, the relative position relationship between the MEMS gyroscope combination and the star sensor 1 is confirmed, and the installation of the single-axis MEMS gyroscope 5 is fine-tuned until the installation accuracy requirements are met.

[0052] The large dynamic star sensor integrated with a high-precision MEMS gyroscope described in this embodiment realizes the complementary advantages of the star sensor and the gyroscope within the product through the integration of the star sensor and the MEMS gyroscope, thereby improving the accuracy and stability; the integrated product reduces the dependence on external auxiliary equipment, realizes data interaction and processing within the product, and enhances autonomy; the integrated product can quickly respond to posture changes through an internally optimized data processing algorithm, thereby improving the response speed and flexibility; the product volume, weight and power consumption are reduced, thereby realizing the miniaturization and low-cost design of the product.

[0053] Embodiment 2:

[0054] A working method of a large dynamic star sensor integrated with a high-precision MEMS gyroscope is implemented based on the large dynamic star sensor integrated with a high-precision MEMS gyroscope described in Example 1, and includes the following steps:

[0055] S1. The MEMS gyro combination measures the angular rate information on the three axes of the star sensor body coordinate system, and uses the SPI interface to transmit the collected angular rate information on the three axes to the star sensor;

[0056] Furthermore, in step S1, x is set st ,y st 、z st are the x-axis coordinate, y-axis coordinate, and z-axis coordinate of the star sensor, me ,y me 、z me The x-axis coordinate, y-axis coordinate, and z-axis coordinate of the MEMS gyroscope combination;

[0057] S2. The star sensor performs accurate attitude prediction, star map recognition and matching, and attitude calculation based on the angular rate information on the three axes obtained in step S1, and then fuses the predicted attitude and the measured attitude to obtain the final output attitude information and angular rate information;

[0058] Furthermore, the specific implementation method of data fusion of the predicted posture and the measured posture in step S2 includes the following steps:

[0059] S2.1. Set the angular rate estimate measured by the MEMS gyro assembly The expression is:

[0060]

[0061] Among them, ω g,k is the angular rate output by the MEMS gyro combination at the kth frame, are the estimated angular rates of the kth frame of the MEMS gyroscope combination on the x-axis, y-axis, and z-axis, respectively. is the estimated value of the k-th frame constant drift of the MEMS gyro assembly;

[0062] S2.2. Predict the attitude of the next measurement cycle based on the estimated angular rate measured by the MEMS gyro combination obtained in step S2.1, expressed as:

[0063]

[0064] Among them, Q k is the k-th frame pose, Q k+1 / k is the predicted k+1th frame posture, T is the data update period, λ is the rotation angle within a period, ω x，k+1 is the x-axis angular rate output by the MEMS gyro combination in the k+1th frame, ω y,k+1 is the y-axis angular rate output by the MEMS gyro combination in the k+1th frame, ω z,k+1 is the z-axis angular rate output by the MEMS gyro combination in the k+1th frame;

[0065]

[0066] S2.3. Set the state quantity to where q e is the error quaternion, δd is the gyro drift error;

[0067] S2.4. Set the initial value of the state variable X0 = 0 6*1 , initial value of state covariance P0 = 1*10 -10 I 6*6 , gyro constant drift initial value Perform state prediction, measurement update and state correction, and integrate to obtain the updated state quantity, which is expressed as:

[0068]

[0069] Among them, X k+1 is the state quantity of the k+1th frame, q e,k+1 is the error quaternion of the k+1th frame, δd k+1 is the zero bias error of the k+1th frame;

[0070] The estimated attitude and gyro drift are then corrected;

[0071]

[0072] Where Q k+1 is the posture of the k+1th frame, is the estimated value of the k+1th frame constant drift of the MEMS gyro combination.

[0073] Furthermore, in view of the impact of temperature changes on the performance of the MEMS gyroscope combination and the star sensor optical components, aluminum-based silicon carbide is selected to make the mechanical structure of the star sensor and the mechanical structure of the MEMS gyroscope combination, and a semiconductor cooler and a PID control method based on pulse width modulation are used to control the cooler, thereby achieving high-precision temperature control of the mounting surface and ensuring that the star sensor maintains stable working performance in different temperature domains.

[0074] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0075] Although the present application has been described above with reference to specific embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, as long as there is no structural conflict, the various features in the specific embodiments disclosed in the present application may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A large dynamic star sensor integrated with a high-precision MEMS gyroscope, characterized in that: The invention comprises a star sensor (1), wherein a MEMS gyroscope assembly is installed on a base of the star sensor (1), wherein the MEMS gyroscope assembly comprises a main body structure (4) and three single-axis MEMS gyroscopes (5), wherein the three single-axis MEMS gyroscopes (5) are installed on the front side surface, the left side surface and the upper side surface of the main body structure (4), and the installation directions of the three single-axis MEMS gyroscopes (5) respectively coincide with three coordinate axes of the coordinate system of the star sensor (1).

2. A large dynamic star sensor integrated with a high-precision MEMS gyroscope according to claim 1, characterized in that: The deviation between the measuring axis of each single-axis MEMS gyroscope (5) and the coordinate axis of the corresponding star sensor (1) is less than 0.05°.

3. A large dynamic star sensor integrated with a high-precision MEMS gyroscope according to claim 1 or 2, characterized in that: Based on the accurate angular rate information collected by the MEMS gyro combination, the star sensor (1) realizes accurate attitude prediction and processing.

4. The large dynamic star sensor integrated with high-precision MEMS gyroscope according to claim 3, characterized in that: The star sensor (1) and each single-axis MEMS gyroscope (5) use an independent SPI communication line (3) to exchange data. The star sensor (1) uses an FPGA to realize an SPI interface with the single-axis MEMS gyroscope (5), collects data from three single-axis MEMS gyroscopes (5) in parallel, and sends the data to a CPU in the star sensor (1) for data processing.

5. The large dynamic star sensor integrated with high-precision MEMS gyroscope according to claim 4, characterized in that: The installation and adjustment process of the single-axis MEMS gyroscope (5) is as follows: after the single-axis MEMS gyroscope (5) is welded to the flexible printed circuit board, the bottom surface of the gyroscope ceramic tube shell of the single-axis MEMS gyroscope (5) is bonded to the installation plane of the main structure (4); first, bonding is performed to ensure that the bottom surface of the gyroscope ceramic tube shell is parallel to the installation surface of the main structure (4), and then a transfer matrix of the MEMS gyroscope assembly relative to the optical axis of the star sensor (1) is calibrated by a high-precision turntable, the relative position relationship between the MEMS gyroscope assembly and the star sensor (1) is confirmed, and the installation of the single-axis MEMS gyroscope (5) is finely adjusted until the installation accuracy requirement is met.

6. A working method of a large dynamic star sensor integrated with a high-precision MEMS gyroscope, which is realized by relying on a large dynamic star sensor integrated with a high-precision MEMS gyroscope as claimed in any one of claims 1 to 5, characterized in that: The steps include: S1. The MEMS gyro combination measures the angular rate information on the three axes of the star sensor body coordinate system, and uses the SPI interface to transmit the collected angular rate information on the three axes to the star sensor; S2. Based on the angular rate information on the three axes obtained in step S1, the star sensor accurately predicts the attitude, identifies and matches the star map, and calculates the attitude. The predicted attitude and the measured attitude are then fused to obtain the final output attitude information and angular rate information.

7. The method for operating a large dynamic star sensor integrated with a high-precision MEMS gyroscope according to claim 6, characterized in that: In step S1, set x st ,y st 、z st are the x-axis coordinate, y-axis coordinate, and z-axis coordinate of the star sensor, me ,y me 、z me are the x-axis coordinate, y-axis coordinate, and z-axis coordinate of the MEMS gyroscope combination.

8. The method for operating a large dynamic star sensor integrated with a high-precision MEMS gyroscope according to claim 7, characterized in that: The specific implementation method of data fusion of the predicted posture and the measured posture in step S2 includes the following steps: S2.

1. Set the angular rate estimate measured by the MEMS gyro assembly The expression is: Among them, ω g,k is the angular rate output by the MEMS gyro combination at the kth frame, are the estimated angular rates of the kth frame of the MEMS gyroscope combination on the x-axis, y-axis, and z-axis, respectively. is the estimated value of the k-th frame constant drift of the MEMS gyro assembly; S2.

2. Predict the attitude of the next measurement cycle based on the estimated angular rate measured by the MEMS gyro combination obtained in step S2.1, expressed as: Among them, Q k is the k-th frame pose, Q k+1 / k is the predicted k+1th frame posture, T is the data update period, λ is the rotation angle within a period, ω x，k+1 is the x-axis angular rate output by the MEMS gyro combination in the k+1th frame, ω y,k+1 is the y-axis angular rate output by the MEMS gyro combination in the k+1th frame, ω z,k+1 is the z-axis angular rate output by the MEMS gyro combination in the k+1th frame; S2.

3. Set the state quantity to where q e is the error quaternion, δd is the gyro drift error; S2.

4. Set the initial value of the state variable X0 = 0 6*1 , initial value of state covariance P0 = 1*10 -10 I 6*6 , gyro constant drift initial value Perform state prediction, measurement update and state correction, and integrate to obtain the updated state quantity, which is expressed as: Among them, X k+1 is the state quantity of the k+1th frame, q e,k+1 is the error quaternion of the k+1th frame, δd k+1 is the zero bias error of the k+1th frame; The estimated attitude and gyro drift are then corrected; Where Q k+1 is the posture of the k+1th frame, is the estimated value of the k+1th frame constant drift of the MEMS gyro combination.

9. The method for operating a large dynamic star sensor integrated with a high-precision MEMS gyroscope according to claim 8, characterized in that: In view of the impact of temperature changes on the performance of MEMS gyroscope combination and star sensor optical components, aluminum-based silicon carbide is selected to make the mechanical structure of the star sensor and the mechanical structure of the MEMS gyroscope combination. A semiconductor cooler and a PID control method based on pulse width modulation are used to control the cooler, thereby achieving high-precision temperature control of the mounting surface and ensuring that the star sensor maintains stable working performance in different temperature domains.

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