A system-level federated filtering fusion method for multiple star sensors

Abstract

The present invention discloses a system-level federated filtering fusion method for multiple star sensors, comprising the following steps: setting a reference star sensor, determining a reference quaternion and non-reference star sensors; calculating a fusion correction angle for each non-reference star sensor based on installation parameters, quaternion output, and validity flag of each non-reference star sensor; calculating a system fusion coefficient matrix based on data validity judgment of each star sensor; calculating a system fusion correction angle based on a federated filtering algorithm; and correcting the quaternion of the reference star sensor according to the system fusion correction angle to obtain a fused quaternion. The present invention realizes system-level multi-star sensor information fusion under a multi-star sensor configuration, effectively reduces the low-frequency noise level of star sensor attitude determination, improves attitude measurement accuracy and reliability, reduces dependence on single-machine-level star sensor information fusion, and improves the flexibility of system star sensor selection.

Description

Technical Field

[0001] The present invention relates to the field of spacecraft on-orbit operation measurement technology, and in particular to a multi-star sensor system-level federated filtering fusion method. Background Art

[0002] Star sensors are key components for satellite inertial attitude measurement and are the foundation of attitude measurement and control. To improve the reliability of attitude measurement, satellite control systems typically deploy multiple star sensors. A single star sensor's attitude measurement accuracy in the direction perpendicular to the optical axis is significantly higher than that in the direction along the optical axis, but it also produces higher noise levels.

[0003] In the traditional method, a single star sensor has the problem of low accuracy in measuring the satellite's three-axis attitude and large measurement noise. Summary of the Invention

[0004] The purpose of the present invention is to provide a system-level federated filtering fusion method for multiple star sensors. This method aims to solve the problem of low satellite three-axis attitude measurement accuracy and high measurement noise in traditional methods using a single star sensor.

[0005] To achieve the above object, the present invention provides a multi-star sensor system-level federated filtering fusion method, comprising:

[0006] Step S1: Setting a reference star sensor according to system requirements or remote control, and determining a reference quaternion and a non-reference star sensor;

[0007] Step S2: Calculating the fusion correction angle of each non-reference star sensor based on the installation parameters, quaternion output, and validity flag of each non-reference star sensor;

[0008] Step S3: Calculating a system fusion coefficient matrix based on the data validity judgment of each star sensor;

[0009] Step S4: Calculating the system fusion correction angle according to the system fusion coefficient matrix and the fusion correction angle of each non-reference star sensor based on a federated filtering algorithm;

[0010] Step S5: Correcting the quaternion of the reference star sensor according to the fusion correction angle of the system to obtain a fusion quaternion.

[0011] Preferably, there are three reference star sensors and three non-reference star sensors in total, and the three star sensors are respectively: a first star sensor, a second star sensor and a third star sensor.

[0012] Preferably, in step S2, each of the non-star sensor installation parameters includes: the installation deviation quaternion from the first star sensor to the second star sensor is The installation deviation quaternion from the second star sensor to the third star sensor is The installation deviation quaternion from the third star sensor to the first star sensor is

[0013] Preferably, in step S2, the quaternion outputs of each non-reference star sensor are: the transformation quaternion from the first star sensor to the second star sensor is The transformation quaternion from the second star sensor to the third star sensor is The transformation quaternion from the third star sensor to the first star sensor is:

[0014] The quaternion of the system relative to the inertial system calculated by the first star sensor is: The quaternion of the system relative to the inertial system calculated by the second star sensor is: The quaternion of this system relative to the inertial system calculated by the third star sensor is:

[0015] Preferably, in step S2, the validity flags of each of the non-reference star sensors are: the validity flag of the first star sensor quaternion obtained by system-level diagnosis is Valid1, the validity flag of the second star sensor quaternion obtained by system-level diagnosis is Valid2, and the validity flag of the third star sensor quaternion obtained by system-level diagnosis is Valid3.

[0016] Preferably, in step S2, the specific calculation steps of the fusion correction angle of each non-sight sensor include:

[0017] If the first sensor is selected as the reference star sensor, the reference quaternion is the quaternion of the first star sensor:

[0018]

[0019] Determine whether Valid2==1 is true. If Valid2==1 is not true, the fusion correction angle Δ of the second star sensor is ST2 Take it as

[000] T If Valid2==1, then calculate the corrected quaternion of the second star sensor The corrected quaternion of the second star sensor The calculation expression is:

[0020]

[0021] The corrected quaternion of the second star sensor Converted to the fusion correction angle Δ of the second star sensor ST2 , the fusion correction angle Δ of the second star sensor ST2 The calculation expression is:

[0022]

[0023] Among them, quat2Angle is a function that converts quaternion into Euler angle, and the conversion order is required to be 123.

[0024] Determine whether Valid3==1 is true. If Valid3==1 is not true, then the fusion correction angle Δ of the third star sensor is ST3 Take it as

[000] T If Valid3==1, then calculate the corrected quaternion of the third star sensor The fusion correction angle Δ of the third star sensor ST3 The calculation expression is:

[0025]

[0026] The corrected quaternion Δ of the third star sensor ST3 Converted to the fusion correction angle Δ of star sensor 3 ST3 , the fusion correction angle Δ of the second star sensor ST3 The calculation expression is:

[0027]

[0028] Preferably, in step S3, the specific calculation steps of the system fusion coefficient matrix F include:

[0029] The ground calculates the deviation coefficient matrix P of each star sensor based on the nominal installation relationship of each star sensor. i , whose expression is:

[0030]

[0031] Calculate the fusion coefficient matrix F of the first star sensor, the second star sensor and the third star sensor 123 :

[0032] F 123 =(P1+P2+P3) -1

[0033] Calculate the fusion coefficient matrix F of the first star sensor and the second star sensor 12 :

[0034] F 12 =(P1+P2) -1

[0035] Calculate the fusion coefficient matrix F of the first star sensor and the third star sensor 13 :

[0036] F 13 =(P1+P3) -1

[0037] Calculate the fusion coefficient matrix F of the second star sensor and the third star sensor 23 :

[0038] F 23 =(P2+P3) -1

[0039] Assuming the first star sensor as the reference star sensor, the system fusion coefficient matrix F is:

[0040]

[0041] Preferably, in step S4, the fusion correction angle Δ of the system is calculated by the federated filtering algorithm. R The specific steps include:

[0042]

[0043] Preferably, in step S5, the reference star sensor quaternion is corrected according to the fusion correction angle of the system to obtain the fusion quaternion Q bi_R , the calculation steps include:

[0044]

[0045] Among them, angle2quat is the Euler angle to quaternion function, and the conversion order is 123.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The present invention sets a reference star sensor and uses it as a reference, calculates the fusion correction angle of non-reference star sensors based on their installation, quaternion output and validity flag, calculates a system fusion coefficient matrix according to the data validity of all configured star sensors, calculates the system fusion correction angle through federated filtering, corrects the reference star sensor quaternion to obtain the system fusion quaternion, realizes system-level multi-star sensor information fusion under multi-star sensor configuration, effectively reduces the low-frequency noise level of star sensor attitude determination, improves attitude measurement accuracy and reliability, reduces dependence on single-machine star sensor information fusion, and improves the flexibility of system star sensor selection. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for the description. Obviously, the drawings described below are one embodiment of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort:

[0049] Figure 1 The present invention provides a flowchart of a multi-star sensor system-level federated filtering fusion method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0050] The following is combined with Figure 1 The specific implementation method of the present invention is further described in detail. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are in a very simplified form and are not in precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the implementation method of the present invention. In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, please refer to the drawings. It should be noted that the structure, proportion, size, etc. shown in the drawings of this specification are only used to match the content disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the implementation conditions of the present invention. Therefore, they have no technical significance. Any modification of the structure, change in the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention.

[0051] Given that traditional methods have problems with single star sensors measuring satellite three-axis attitude with low accuracy and high measurement noise, to improve system quaternion accuracy and suppress quaternion noise, this embodiment provides a system-level federated filtering fusion method for multiple star sensors, including:

[0052] Step S1: Setting a reference star sensor according to system requirements or remote control, and determining a reference quaternion and non-reference star sensors.

[0053] There are three reference star sensors and three non-reference star sensors in total, and the three star sensors are respectively: a first star sensor, a second star sensor and a third star sensor.

[0054] Step S2: Calculating the fusion correction angle of each non-reference star sensor based on the installation parameters, quaternion output and validity flag of each non-reference star sensor.

[0055] Each of the non-star sensor installation parameters includes: the installation deviation quaternion from the first star sensor to the second star sensor is The installation deviation quaternion from the second star sensor to the third star sensor is The installation deviation quaternion from the third star sensor to the first star sensor is

[0056] The quaternion outputs of each non-reference star sensor are: the transformation quaternion from the first star sensor to the second star sensor is The transformation quaternion from the second star sensor to the third star sensor is The transformation quaternion from the third star sensor to the first star sensor is:

[0057] The quaternion of the system relative to the inertial system calculated by the first star sensor is: The quaternion of the system relative to the inertial system calculated by the second star sensor is: The quaternion of this system relative to the inertial system calculated by the third star sensor is:

[0058] The validity flags of each of the non-reference star sensors are: the validity flag of the first star sensor quaternion obtained by system-level diagnosis is Valid1, the validity flag of the second star sensor quaternion obtained by system-level diagnosis is Valid2, and the validity flag of the third star sensor quaternion obtained by system-level diagnosis is Valid3.

[0059] The specific calculation steps of the fusion correction angle of each non-sight sensor include:

[0060] If the first sensor is selected as the reference star sensor, the reference quaternion is the quaternion of the first star sensor:

[0061]

[0062] Determine whether Valid2==1 is true. If Valid2==1 is not true, the fusion correction angle Δ of the second star sensor is ST2 Take it as

[000] T If Valid2==1, then calculate the corrected quaternion of the second star sensor The corrected quaternion of the second star sensor The calculation expression is:

[0063]

[0064] The corrected quaternion of the second star sensor Converted to the fusion correction angle Δ of the second star sensor ST2, the fusion correction angle Δ of the second star sensor ST2 The calculation expression is:

[0065]

[0066] Among them, quat2Angle is a function that converts quaternion into Euler angle, and the conversion order is required to be 123.

[0067] Determine whether Valid3==1 is true. If Valid3==1 is not true, then the fusion correction angle Δ of the third star sensor is ST3 Take it as

[000] T If Valid3==1, then calculate the corrected quaternion of the third star sensor The fusion correction angle Δ of the third star sensor ST3 The calculation expression is:

[0068]

[0069] The corrected quaternion Δ of the third star sensor ST3 Converted to the fusion correction angle Δ of star sensor 3 ST3 , the fusion correction angle Δ of the second star sensor ST3 The calculation expression is:

[0070]

[0071] Step S3: Calculating a system fusion coefficient matrix based on the data validity judgment of each star sensor.

[0072] In step S3, the specific calculation steps of the system fusion coefficient matrix F include:

[0073] The ground calculates the deviation coefficient matrix P of each star sensor based on the nominal installation relationship of each star sensor. i , whose expression is:

[0074]

[0075] Calculate the fusion coefficient matrix F of the first star sensor, the second star sensor and the third star sensor 123 :

[0076] F 123 =(P1+P2+P3) -1 (7)

[0077] Calculate the fusion coefficient matrix F of the first star sensor and the second star sensor 12 :

[0078] F12 =(P1+P2) -1 (8)

[0079] Calculate the fusion coefficient matrix F of the first star sensor and the third star sensor 13 :

[0080] F 13 =(P1+P3) -1 (9)

[0081] Calculate the fusion coefficient matrix F of the second star sensor and the third star sensor 23 :

[0082] F 23 =(P2+P3) -1 (10)

[0083] Assuming the first star sensor as the reference star sensor, the system fusion coefficient matrix F is:

[0084]

[0085] Step S4: Calculating the system fusion correction angle according to the system fusion coefficient matrix and the fusion correction angle of each non-reference star sensor based on a federated filtering algorithm;

[0086] The fusion correction angle of the system is Δ R , the specific steps include:

[0087]

[0088] Step S5: According to the fusion correction angle of the system, the quaternion of the reference star sensor is corrected to obtain the fusion quaternion Q bi_R , the calculation steps include:

[0089]

[0090] Among them, angle2quat is the Euler angle to quaternion function, and the conversion order is 123.

[0091] In summary, this embodiment, when deploying multiple star sensors, obtains a reference quaternion by setting a reference star sensor. The fusion correction angle for each non-reference star sensor is calculated based on the installation, quaternion output, and validity flag of each non-reference star sensor. The system fusion coefficient matrix is ​​calculated based on the data validity of each star sensor. A federated filtering algorithm is used to convert the fusion coefficient matrix and fusion correction angle into a system fusion correction angle. The system correction angle is then used to correct the reference quaternion to obtain a system fusion quaternion. The low-frequency noise of the system-level federated filtering fusion quaternion is an order of magnitude lower than that of a single star sensor, resulting in higher system reliability.

[0092] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0093] It should be noted that the devices and methods disclosed in the embodiments of this document may also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of the devices, methods, and computer program products according to the various embodiments of this document. In this regard, each box in the flowchart or block diagram may represent a module, program, or portion of code, wherein the module, program segment, or portion of code contains one or more executable instructions for implementing a specified logical function, and the module, program segment, or portion of code contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the boxes may also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes may actually be executed substantially in parallel, or they may sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart, may be implemented by a dedicated hardware-based system for performing the specified function or action, or may be implemented by a combination of dedicated hardware and computer instructions.

[0094] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description is not intended to limit the present invention. After reading the above description, various modifications and substitutions of the present invention will become apparent to those skilled in the art. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A multi-star sensor system-level federated filtering fusion method, characterized in that: include: Step S1: Setting a reference star sensor according to system requirements or remote control, and determining a reference quaternion and a non-reference star sensor; Step S2: Calculating the fusion correction angle of each non-reference star sensor based on the installation parameters, quaternion output, and validity flag of each non-reference star sensor; Step S3: Based on the data validity judgment of each star sensor, the system fusion coefficient matrix is ​​calculated. The specific calculation steps of the system fusion coefficient matrix F include: The ground calculates the deviation coefficient matrix P of each star sensor based on the nominal installation relationship of each star sensor. i , whose expression is: Among them, A bSTi represents the conversion matrix from this system to each of the star sensors; Q bi0 Represents the base quaternion; Calculate the fusion coefficient matrix F of the first star sensor, the second star sensor and the third star sensor 123 : F 123 =(P1+P2+P3) -1 Calculate the fusion coefficient matrix F of the first star sensor and the second star sensor 12 : F 12 =(P1+P2) -1 Calculate the fusion coefficient matrix F of the first star sensor and the third star sensor 13 : F 13 =(P1+P3) -1 Calculate the fusion coefficient matrix F of the second star sensor and the third star sensor 23 : F 23 =(P2+P3) -1 Assuming the first star sensor as the reference star sensor, the system fusion coefficient matrix F is: Wherein, Valid1 represents the validity flag of the first star sensor quaternion obtained by system-level diagnosis, Valid2 represents the validity flag of the second star sensor quaternion obtained by system-level diagnosis, and Valid3 represents the validity flag of the third star sensor quaternion obtained by system-level diagnosis; Step S4: Calculating the system fusion correction angle according to the system fusion coefficient matrix and the fusion correction angle of each non-reference star sensor based on a federated filtering algorithm; Step S5: Correcting the quaternion of the reference star sensor according to the fusion correction angle of the system to obtain a fused quaternion.

2. The multi-star sensor system-level federated filtering fusion method according to claim 1, wherein: There are three reference star sensors and three non-reference star sensors in total, and the three star sensors are respectively: a first star sensor, a second star sensor and a third star sensor.

3. The multi-star sensor system-level federated filtering fusion method according to claim 2, wherein: In step S2, the installation parameters of each non-reference star sensor include: the installation deviation quaternion from the first star sensor to the second star sensor is The installation deviation quaternion from the second star sensor to the third star sensor is The installation deviation quaternion from the third star sensor to the first star sensor is 4. The multi-star sensor system-level federated filtering fusion method according to claim 3, wherein: In step S2, the quaternion outputs of each non-reference star sensor are: the transformation quaternion from the first star sensor to the second star sensor is The transformation quaternion from the second star sensor to the third star sensor is The transformation quaternion from the third star sensor to the first star sensor is: The quaternion of the system relative to the inertial system calculated by the first star sensor is: The quaternion of the system relative to the inertial system calculated by the second star sensor is: The quaternion of this system relative to the inertial system calculated by the third star sensor is:

5. The multi-star sensor system-level federated filtering fusion method according to claim 4, characterized in that: In step S2, the validity flags of each of the non-reference star sensors are: the validity flag of the first star sensor quaternion obtained by system-level diagnosis is Valid1, the validity flag of the second star sensor quaternion obtained by system-level diagnosis is Valid2, and the validity flag of the third star sensor quaternion obtained by system-level diagnosis is Valid3.

6. The multi-star sensor system-level federated filtering fusion method according to claim 5, characterized in that: In step S2, the fusion correction angle of each non-reference star sensor is calculated by the following specific steps: If the first star sensor is selected as the reference star sensor, then the reference quaternion Q bi0 The quaternion for the first star sensor is: Determine whether Valid2==1 is true. If Valid2==1 is not true, the fusion correction angle Δ of the second star sensor is ST2 Take it as [0 0 0] T If Valid2==1, then calculate the corrected quaternion of the second star sensor The corrected quaternion of the second star sensor The calculation expression is: in, Represents the installation quaternion of the second star sensor; The corrected quaternion of the second star sensor Converted to the fusion correction angle Δ of the second star sensor ST2 , the fusion correction angle Δ of the second star sensor ST2 The calculation expression is: Among them, quat2Angle is the function that converts quaternion into Euler angle, and the conversion order is required to be 123; Determine whether Valid3==1 is true. If Valid3==1 is not true, the fusion correction angle Δ of the third star sensor is ST3 Take it as [0 0 0] T If Valid3==1, then calculate the corrected quaternion of the third star sensor The fusion correction angle Δ of the third star sensor ST3 The calculation expression is: in, Represents the installation quaternion of the third star sensor; The corrected quaternion Δ of the third star sensor ST3 Converted to the fusion correction angle Δ of star sensor 3 ST3 , the fusion correction angle Δ of the second star sensor ST3 The calculation expression is:

7. The multi-star sensor system-level federated filtering fusion method according to claim 6, characterized in that: In step S4, the system fusion correction angle Δ is calculated by the federated filtering algorithm. R The specific steps include:

8. The multi-star sensor system-level federated filtering fusion method according to claim 7, wherein: In step S5, the reference star sensor quaternion is corrected according to the fusion correction angle of the system to obtain the fusion quaternion Q bi_R , the calculation steps include: Among them, angle2quat is the Euler angle to quaternion function, and the conversion order is required to be 123.

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