Night inertia, starlight and polarization integrated navigation method and device considering measurement failure

Abstract

The invention discloses a night inertia, starlight and polarization integrated navigation method and device considering measurement failure, and belongs to the technical field of autonomous navigation, the method comprises the following steps: calculating to obtain a moon vector under a carrier coordinate system b, a corresponding moon vector under a navigation coordinate system n and an optical axis vector pointed by a star sensor; calculating to obtain a measurement vector error, defining a state vector and establishing a state equation of the integrated navigation system; according to whether inertial navigation, star sensor and polarization information participate in measurement or not, measurement matrixes only in three different modes of inertia, inertia and starlight and inertia and starlight and polarization are obtained, a measurement model is established, and three types of filtering modes are obtained; in the filtering process of the integrated navigation system, when measurement is updated, fault diagnosis is carried out by using a chi-square test method based on a residual # imgabs0 #, and graded switching is carried out among different modes, so that optimal integrated navigation attitude estimation is realized. According to the invention, the robustness of the system is improved, and continuous and reliable navigation under complex weather conditions is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of satellite autonomous navigation, and in particular relates to a nighttime inertial, starlight and polarization combined navigation method and device taking measurement failure into consideration. Background Art

[0002] With the development of autonomous navigation technology, astronomical navigation systems based on star sensors have gained widespread application. Star sensors achieve attitude calculation through star point perception and star pattern recognition, offering significant advantages such as zero error accumulation and immunity to electromagnetic interference. However, traditional star sensors mostly employ a narrow field of view (FOV < 20°). While this improves the resolution of the observed star pattern, it is susceptible to interference from clouds, vegetation, and buildings, leading to observation failures. Measurement data from sensor anomalies also limits their practical application in engineering applications.

[0003] Bionic polarization navigation acquires navigation information by sensing the distribution pattern of polarized light in the sky. At night, the primary source of polarized light in the sky is moonlight. This is typically accomplished by using an imaging polarization sensor with a field of view (FOV) >170° to collect full-sky polarization data, enabling heading calculation. Bionic polarization navigation also offers the advantages of being passive and radiation-free, with no accumulated errors over time. Inspired by the coordinated navigation of dung beetles using starlight and polarization cues, nighttime integrated navigation systems that integrate astronomical and polarization navigation have become a research hotspot.

[0004] However, existing methods do not take into account the reduced or even failure of sensor measurement accuracy caused by complex scenes and tasks such as low light intensity and poor visibility at night. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A nighttime inertial, starlight, and polarization integrated navigation method considering measurement failures includes:

[0007] Step 1: Use the polarization sensor to measure the polarization information in the current posture and calculate the moon vector in the carrier coordinate system b. ;According to the astronomical calendar, obtain the corresponding moon vector in the navigation coordinate system n ; Use the star sensor to measure the optical axis vector of the sensor in the n system ;

[0008] Step 2: Based on the inertial navigation attitude array Get the predicted value of the star-sensing optical axis vector and the predicted value of the moon vector ; Calculate the difference between the measured vector and the predicted value of the star sensor and polarization sensor respectively and , and obtain the measurement vector error ;

[0009] Step 3: Measure the vector error As the system state, combined with the inertial error equation, the state vector is defined And establish the state equation of the integrated navigation system;

[0010] Step 4: According to whether the inertial navigation, star sensitivity and polarization information participate in the measurement, obtain the measurement matrix of three different modes: inertial only, inertial and starlight, inertial and starlight and polarization. 、 and , establish a measurement model and obtain three types of filtering modes: I mode, IC mode, and ICP mode;

[0011] Step 5: During the filtering process of the integrated navigation system, when the measurement is updated, the residual-based The chi-square test method is used for fault diagnosis and hierarchical switching between different modes is performed to achieve the optimal combined navigation attitude estimation.

[0012] A nighttime inertial, starlight, and polarization combined navigation device taking into account measurement failures comprises:

[0013] The vector calculation module uses the polarization sensor to measure the polarization information under the current posture and calculates the moon vector in the carrier coordinate system b. ;According to the astronomical calendar, obtain the corresponding moon vector in the navigation coordinate system n ; Use the star sensor to measure the optical axis vector of the sensor in the n system ;

[0014] Measurement vector error acquisition module, based on inertial navigation attitude array Get the predicted value of the star-sensing optical axis vector and the predicted value of the moon vector ; Calculate the difference between the measured vector and the predicted value of the star sensor and polarization sensor respectively and , and obtain the measurement vector error ;

[0015] The state equation establishment module measures the vector error As the system state, combined with the inertial error equation, the state vector is defined And establish the state equation of the integrated navigation system;

[0016] The filter mode acquisition module obtains the measurement matrix of three different modes: inertial only, inertial and starlight, and inertial and starlight and polarization, according to whether the inertial navigation, star sensitivity and polarization information participate in the measurement. 、 and , three measurement models are established, and then three types of filtering modes are obtained: I mode, IC mode, and ICP mode;

[0017] Filtering module, in the filtering process of the integrated navigation system, when the measurement is updated, the residual-based The chi-square test method is used for fault diagnosis and hierarchical switching between different modes is performed to achieve the optimal combined navigation attitude estimation.

[0018] An electronic device comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the nighttime inertial, starlight and polarization combined navigation method taking into account measurement failure are implemented.

[0019] A non-transitory computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the nighttime inertial, starlight and polarization combined navigation method taking measurement failure into account.

[0020] The present invention has the following beneficial effects:

[0021] (1) The present invention directly adds the original observation vectors of the star sensor and polarization sensor into the integrated navigation system, avoiding the additional errors introduced by the sensors in the independent attitude solution process; at the same time, the chi-square test is used to diagnose the measurement faults, thereby continuously outputting reliable carrier attitude information, improving the accuracy and autonomy of the navigation system.

[0022] (2) Aiming at the intermittent observation failure risk of star sensors and polarization sensors in complex nighttime scenes, the present invention designs a hierarchical navigation mode architecture, combines it with real-time fault detection and intelligent switching mechanism, and performs hierarchical switching of different navigation modes based on the chi-square test results, thereby improving the robustness of the system and achieving continuous and reliable navigation under complex weather conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The figure is a flow chart of the nighttime inertial, starlight and polarization combined navigation method taking into account measurement failure of the present invention. DETAILED DESCRIPTION

[0024] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0025] like Figure 1As shown, the nighttime inertial, starlight and polarization combined navigation method considering measurement failure of the present invention includes:

[0026] Step 1: Use the polarization sensor to measure the polarization information in the current posture and calculate the moon vector in the carrier coordinate system b. , the moon vector output by the polarization sensor Expressed as:

[0027] ;

[0028] in, and Represent the altitude and azimuth of the moon respectively.

[0029] According to the astronomical calendar, the corresponding moon vector in the navigation coordinate system n can be obtained Specifically, according to the built-in clock information and astronomical calendar information of the carrier, the right ascension and declination of the moon in the navigation coordinate system n at the current moment can be obtained, and then the moon vector in the n system can be obtained. .

[0030] The optical axis vector of the sensor pointing to the n-axis is obtained by measuring the star sensor Specifically, the starlight information in the b-frame is obtained by measuring the star sensor. By matching the star map, the right ascension and declination of the central optical axis of the star sensor in the n-frame can be obtained, and then the optical axis vector of the star sensor in the n-frame can be obtained. .

[0031] Step 2: Based on the inertial navigation attitude array The predicted value of the star-sensitive optical axis vector can be obtained and the predicted value of the moon vector ; Calculate the difference between the measured vector and the predicted value of the star sensor and polarization sensor respectively and , and obtain the measurement vector error ;

[0032] Step 2.1, based on inertial navigation attitude array Get the predicted value of the star-sensing optical axis vector , the star-sensitive optical axis vector in the b system and the star-sensitive optical axis vector in the n system The conversion relationship between them is:

[0033] ;

[0034] in, To convert the vector from the navigation system to the direction cosine matrix of the inertial navigation system, is the identity matrix, is the antisymmetric matrix of the attitude misalignment angle vector, Represents the calculation system obtained by inertial navigation calculation.

[0035] Step 2.2, based on inertial navigation attitude array , the estimated star sensor optical axis vector prediction value Expressed as:

[0036] ;

[0037] in, Inertial navigation attitude array The inverse transform of .

[0038] Step 2.3, obtain the star sensor measurement vector error:

[0039] ;

[0040] Among them, for the star sensor installed in the b system, the star-sensing optical axis vector is the observation direction of the star sensor, which can be expressed as .

[0041] Step 2.4, based on the inertial navigation attitude array Get the predicted value of the moon vector , the moon vector in the n-frame obtained based on the astronomical calendar ,pass Get the predicted value of the moon vector in the b system The moon vector measured by the polarization sensor and the predicted value of the moon vector in the b system The difference is the moon vector measurement error:

[0042] ;

[0043] in, Indicates constructing the vector into an antisymmetric matrix, is the attitude misalignment angle.

[0044] Step 2.5: For the inertial, starlight, and polarimetric integrated navigation systems, calculate the difference between the measured vectors of the star sensor and polarimetric sensor and the predicted values. and , and obtain the measurement vector error .

[0045] Step 3: Measure the vector error As the system state, combined with the inertial error equation, the state vector is defined And establish the state equation. In the inertial, starlight and polarization combined navigation system, based on the inertial error equation, combined with the measurement vector error , you can get the system status:

[0046] ;

[0047] in, is the attitude misalignment angle, is the speed error, is the position error, is the random drift of the gyroscope, is the random deviation of the accelerometer.

[0048] Further obtain the state equation of the integrated navigation system:

[0049] ;

[0050] in, is the state matrix of the inertial, starlight and polarization integrated navigation system, is the noise factor matrix of the inertial, starlight and polarization integrated navigation system, is the process noise vector.

[0051] Step 4: According to whether the inertial navigation, star sensitivity and polarization information participate in the measurement, obtain the measurement matrix of three different modes: inertial only, inertial and starlight, inertial and starlight and polarization. 、 and , three measurement models are established, and then the corresponding I, IC, and ICP filtering modes are obtained.

[0052] Due to the different update frequencies of inertial information, star sensitivity and polarization information, three combination modes are designed according to whether inertial navigation, star sensitivity and polarization information participate in the measurement. According to the type of navigation information involved in the measurement, the measurement matrix of three different modes, namely inertial only, inertial and starlight, and inertial, starlight and polarization, is obtained. 、 and .

[0053] Since the inertial information is updated most frequently, there is an I mode in which only the inertial measurement is updated. In this mode, only the measurement information of the accelerometer in the inertial navigation is updated. The corresponding measurement model is:

[0054] ;

[0055] in, is the measurement noise in I mode, It can be expressed as:

[0056] ;

[0057] in, Represents the acceleration due to gravity.

[0058] The star sensor is updated more frequently than the polarization sensor. There is an IC mode that updates both inertial and star sensor measurements. In this mode, in addition to inertial measurement information updates, star sensor measurement information is also updated. In IC mode, the corresponding measurement model is:

[0059] ;

[0060] in, is the measurement noise in IC mode, . It can be expressed as:

[0061] ;

[0062] in, Indicates constructing a vector into an antisymmetric matrix.

[0063] When inertial, star sensitivity, and polarization information are updated simultaneously, the ICP mode can be used. In ICP mode, the corresponding measurement model is:

[0064] ;

[0065] in, is the measurement noise in ICP mode, ; It can be expressed as:

[0066] ;

[0067] In the designed integrated navigation system, the inertial navigation system is used as the reference system and is combined with the navigation information of the star sensor and polarization sensor. It is divided into three filtering modes: I, IC, and ICP according to the measurement information update.

[0068] Step 5: During the filtering process of the integrated navigation system, when the measurement is updated, the residual-based The chi-square test method is used for fault diagnosis and hierarchical switching between different modes is performed to achieve the optimal combined navigation attitude estimation.

[0069] Considering that star sensors and polarization sensors may be affected by the environment, such as occlusion, fog, artificial light and other factors, which may cause sensor failure or accuracy degradation, fault detection is performed on the IC and ICP modes that include star sensor measurement updates and polarization measurement updates.

[0070] When the navigation system operates in ICP mode, filtering is performed based on the state equation and measurement equation of the mode, and the residual-based Fault diagnosis is performed using the chi-square test method. If the test passes, the ICP mode is run. If the test fails, the IC mode is switched and the residual error is used again. If the test passes, the IC mode is maintained; otherwise, the operation is further downgraded to the I mode.

[0071] When the navigation system is operating in IC mode, it uses the residual The chi-square test method is used for fault diagnosis. If the test passes, the IC mode is maintained; if it fails, the mode is switched to the I mode.

[0072] In addition, according to the established inertial, starlight and polarization combined navigation model, based on the combination mode under different scenarios and fault conditions, Kalman filtering is used to estimate the three-dimensional attitude misalignment angle during measurement update, and the optimal attitude estimation is obtained through multi-mode switching, thereby realizing the attitude correction of the carrier.

[0073] The contents not described in detail in the specification of the present invention belong to the common knowledge of professionals in this field.

[0074] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROMs, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present invention may be implemented using various computer languages.

[0075] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0076] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0077] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0078] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0079] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

[0080] The above descriptions are merely embodiments of the present invention and are not intended to limit the scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied to other related system fields, are also included in the scope of protection of the present invention.

Claims

1. A nighttime inertial, starlight, and polarization combined navigation method taking into account measurement failures, characterized in that: include: Step 1: Use the polarization sensor to measure the polarization information in the current posture and calculate the moon vector in the carrier coordinate system b. ; Obtain the moon vector corresponding to the navigation coordinate system n according to the astronomical calendar ; Use the star sensor to measure the optical axis vector of the sensor in the n system ; Step 2: Based on the inertial navigation attitude array Get the predicted value of the star-sensing optical axis vector and the predicted value of the moon vector ; Calculate the difference between the measured vector and the predicted value of the star sensor and polarization sensor respectively and , and obtain the measurement vector error ; Step 3: Measure the vector error As the system state, combined with the inertial error equation, the state vector is defined And establish the state equation of the integrated navigation system; Step 4: According to whether the inertial navigation, star sensitivity and polarization information participate in the measurement, obtain the measurement matrix of three different modes: inertial only, inertial and starlight, inertial and starlight and polarization. 、 and , establish a measurement model and obtain three types of filtering modes: I mode, IC mode, and ICP mode; Step 5: During the filtering process of the integrated navigation system, when the measurement is updated, the residual-based The chi-square test method is used for fault diagnosis and hierarchical switching between different modes is performed to achieve the optimal combined navigation attitude estimation.

2. The nighttime inertial, starlight, and polarization combined navigation method considering measurement failure according to claim 1, characterized in that: Step 5 also includes: according to the established inertial, starlight and polarization combined navigation model, based on the combination mode under different scenarios and fault conditions, using Kalman filtering to estimate the three-dimensional attitude misalignment angle during measurement update, and obtaining the optimal attitude estimation through hierarchical switching between different modes to achieve attitude correction of the carrier.

3. The nighttime inertial, starlight, and polarization combined navigation method considering measurement failure according to claim 1, characterized in that: In step 1, the moon vector Expressed as: ； in, and Represent the altitude and azimuth of the moon respectively.

4. The nighttime inertial, starlight, and polarization combined navigation method considering measurement failure according to claim 3 is characterized in that: Step 2 includes: Step 2.1, based on inertial navigation attitude array Get the predicted value of the star-sensing optical axis vector , the star-sensitive optical axis vector in the b system and the star-sensitive optical axis vector in the n system The conversion relationship between them is: ； in, To convert the vector from the navigation system to the direction cosine matrix of the inertial navigation system, is the identity matrix, is the antisymmetric matrix of the attitude misalignment angle vector, represents the calculation system obtained by inertial navigation calculation; Step 2.2, based on inertial navigation attitude array , the estimated star sensor optical axis vector prediction value Expressed as: ； in, Inertial navigation attitude array The inverse transform of Step 2.3, obtain the star sensor measurement vector error: ； Among them, for the star sensor installed in the b system, the star-sensing optical axis vector is the observation direction of the star sensor, which is expressed in the b system as ; Step 2.4, based on the inertial navigation attitude array Get the predicted value of the moon vector , the moon vector in the n-frame obtained based on the astronomical calendar ,pass Get the predicted value of the moon vector in the b system ; The moon vector measured by the polarization sensor and the predicted value of the moon vector in the b system The difference is the moon vector measurement error: ； in, Indicates constructing the vector into an antisymmetric matrix, is the attitude misalignment angle; Step 2.5: Calculate the difference between the measured vector and the predicted value of the star sensor and polarization sensor respectively and , and obtain the measurement vector error .

5. The nighttime inertial, starlight and polarization combined navigation method considering measurement failure according to claim 4 is characterized in that: In step 3, in the inertial, starlight and polarization combined navigation system, based on the inertial error equation, combined with the measurement vector error , the system status is as follows: ； in, is the attitude misalignment angle, is the speed error, is the position error, is the random drift of the gyroscope, is the random deviation of the accelerometer; Then the state equation of the integrated navigation system is obtained: ； in, is the state matrix of the inertial, starlight and polarization integrated navigation system, is the noise factor matrix of the inertial, starlight and polarization integrated navigation system, is the process noise vector.

6. The nighttime inertial, starlight and polarization combined navigation method considering measurement failure according to claim 5, characterized in that: Step 4 includes: obtaining the measurement matrices of the three different modes: I mode (inertial update only), IC mode (inertial and starlight update), and ICP mode (inertial, starlight and polarization update), according to the type of navigation information involved in the measurement. 、 and ; The measurement model corresponding to the I mode is: ； in, is the measurement noise in I mode, where for: ； in, is the acceleration due to gravity; The measurement model corresponding to the IC mode is: ； in, is the measurement noise in IC mode, , for: ； in, Indicates constructing the vector into an antisymmetric matrix; The measurement model corresponding to the ICP mode is: ； in, is the measurement noise in ICP mode, , for: 。 7. The nighttime inertial, starlight and polarization combined navigation method considering measurement failure according to claim 6, characterized in that: Step 5 includes: when the navigation system is operating in the ICP mode, performing filtering based on the state equation and measurement equation of the mode, and using the residual-based The chi-square test method is used for fault diagnosis; if the test is passed, the ICP mode is run; if the test is not passed, the IC mode is switched and the residual error is used again. Chi-square test method, if the test passes, keep IC mode, otherwise further downgrade to I mode; When the navigation system is operating in IC mode, it uses the residual The chi-square test method is used for fault diagnosis. If the test passes, the IC mode is maintained; if it fails, the mode is switched to the I mode.

8. A nighttime inertial, starlight, and polarization combined navigation device taking into account measurement failure, characterized in that: include: The vector calculation module uses the polarization sensor to measure the polarization information under the current posture and calculates the moon vector in the carrier coordinate system b. ; Obtain the moon vector corresponding to the navigation coordinate system n according to the astronomical calendar ; Use the star sensor to measure the optical axis vector of the sensor in the n system ; Measurement vector error acquisition module, based on inertial navigation attitude array Get the predicted value of the star-sensing optical axis vector and the predicted value of the moon vector ; Calculate the difference between the measured vector and the predicted value of the star sensor and polarization sensor respectively and , and obtain the measurement vector error ; The state equation establishment module measures the vector error As the system state, combined with the inertial error equation, the state vector is defined And establish the state equation of the integrated navigation system; The filter mode acquisition module obtains the measurement matrix of three different modes: inertial only, inertial and starlight, and inertial and starlight and polarization, according to whether the inertial navigation, star sensitivity and polarization information participate in the measurement. 、 and , three measurement models are established, and then three types of filtering modes are obtained: I mode, IC mode, and ICP mode; Filtering module, in the filtering process of the integrated navigation system, when the measurement is updated, the residual-based The chi-square test method is used for fault diagnosis and hierarchical switching between different modes is performed to achieve the optimal combined navigation attitude estimation.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the nighttime inertial, starlight and polarization combined navigation method considering measurement failure are implemented as claimed in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the nighttime inertial, starlight and polarization integrated navigation method considering measurement failure are implemented as claimed in any one of claims 1 to 7.

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