Inertial device zero position adaptive estimation and compensation method for inertial navigation system

Abstract

The application relates to a kind of inertial navigation system inertial device zero adaptive estimation and compensation method, comprising: 1, complete inertial navigation and installation and electrical connection of supporting combined navigation system;2, inertial navigation and supporting combined navigation system power on, complete initial alignment of inertial navigation;3, inertial navigation enters combined navigation state, vehicle or ship enters running or sailing state;According to the information type of supporting combined navigation system, select corresponding mode to estimate the zero of combined navigation inertial device;4, in the process of zero estimation, always judge the effectiveness of external reference information of supporting combined navigation system, if the effectiveness of external reference information is invalid, it is judged that the zero estimation result of the inertial device is invalid, and the zero of the inertial device is not compensated;Otherwise, then enter step 5 to judge the effectiveness of accelerometer zero estimation and enter step 6 to judge the effectiveness of gyro zero estimation.The application can realize the adaptive judgment of inertial device zero estimation path rationality and the adaptive judgment of zero estimation result effectiveness.

Description

Technical Field

[0001] This invention belongs to the field of zero-position estimation of inertial navigation devices, and particularly relates to an adaptive estimation and compensation method for zero-position of inertial devices in an inertial navigation system. Background Technology

[0002] An inertial navigation system is an autonomous navigation system, and its main source of error is the zero-position error of inertial devices. The presence of inertial device zero positions (including gyroscope zero positions and accelerometer zero positions) directly leads to a decrease in the accuracy of navigation information over time. Since inertial device zero positions are prone to error divergence during long-term operation, compensation for these zero positions can effectively suppress this error, thereby improving navigation accuracy. Furthermore, compensating for inertial device zero positions enhances system stability, ensuring its stability during long-term operation and preventing navigation deviations caused by error accumulation.

[0003] Existing methods for estimating the zero position of inertial devices in inertial navigation systems require operators to manually judge the rationality of the estimated path and the validity of the zero position estimation. Compensation can only be performed if the estimation is valid. This requires operators to have a certain level of inertial navigation knowledge and is not very practical. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes an adaptive estimation and compensation method for the zero position of inertial devices in an inertial navigation system. This method enables adaptive judgment of the rationality of the zero position estimation path and the effectiveness of the zero position estimation results. It also provides online compensation for the effective estimated zero position of the inertial devices, thereby improving the long-term navigation accuracy of the inertial navigation system.

[0005] The above-mentioned objective of this invention is achieved through the following technical solution:

[0006] A method for adaptive zero-position estimation and compensation of inertial devices in an inertial navigation system, characterized by comprising the following steps:

[0007] Step 1: Install the inertial navigation system on the vehicle or ship, and install its matching integrated navigation system on the test vehicle or ship according to its installation method, and complete the electrical connection between the inertial navigation system and the corresponding integrated navigation system.

[0008] Step 2: Power on the inertial navigation system and its integrated navigation system to complete the initial alignment of the inertial navigation system, ensuring that the inertial navigation system can output effective velocity, position and attitude information, and that the integrated navigation system can output effective reference information;

[0009] Step 3: The inertial navigation system enters the integrated navigation state, and the vehicle or ship enters the driving or sailing state; according to the information type of the supporting integrated navigation system, select the corresponding mode to perform zero-position estimation of the integrated navigation inertial devices;

[0010] Step 4: During the inertial device zero-position estimation process in the integrated navigation state, the validity of the external reference information of the supporting integrated navigation system is always judged. If the external reference information is deemed invalid, the zero-position estimation result of this group of inertial devices is deemed invalid, and the zero position of the inertial devices is not compensated. If the external reference information is deemed valid, the process proceeds to Step 5 to judge the validity of the accelerometer zero-position estimation and to Step 6 to judge the validity of the gyroscope zero-position estimation.

[0011] Step 5: Determine the validity of the accelerometer zero-point estimation based on the set criteria;

[0012] Step 6: Determine the validity of the gyroscope zero-position estimation based on the set criteria.

[0013] Furthermore, in step 3, if the supporting integrated navigation system is satellite navigation, the system enters the position combination mode to perform inertial device zero-position estimation; if the supporting integrated navigation system is odometer or DVL, the system enters the velocity combination mode to perform inertial device zero-position estimation. The inertial device zero-position estimation methods in the position combination and velocity combination modes establish state equations and measurement equations based on the characteristics of inertial navigation and integrated information, and use the Kalman filtering method to perform inertial device zero-position estimation.

[0014] Furthermore, in step 4, different validity criteria are designed based on the characteristics of different external reference information, as follows:

[0015] c) The validity criterion for the external reference information of the satellite navigation system used in the integrated navigation system is:

[0016] (3) Determination of single consecutive failure time of external reference satellite guidance data:

[0017] After the inertial device zero-position estimation is performed by the initial position observation integrated navigation system, the single continuous failure time of the satellite navigation data should not exceed 1 minute; otherwise, it is determined that the estimation has failed.

[0018] (4) Determination of total failure time of external reference satellite navigation data:

[0019] After the inertial device zero-position estimation is performed by the initial position observation integrated navigation system, the total failure time of the satellite navigation data shall not exceed 10 minutes; otherwise, the estimation shall be deemed a failure.

[0020] Among them, the failure of satellite navigation data is judged by the valid bit of satellite navigation data, the consistency of satellite navigation data before and after, and the consistency between satellite navigation position and inertial navigation position. If both conditions (1) and (2) in a) are met at the same time, the external reference information of satellite navigation is considered to be valid; otherwise, the external reference information of satellite navigation is determined to be invalid, and the zero position estimation result of the inertial device is invalid.

[0021] d) Criteria for the validity of external reference information in the DVL system for the supporting integrated navigation system

[0022] (3) Determination of single consecutive failure time of external reference DVL data:

[0023] After the inertial device zero-position estimation is performed by the speed observation integrated navigation system, the single continuous failure time of the DVL data should not exceed 1 minute; otherwise, it is determined that the estimation has failed.

[0024] (4) Determining the total failure time of external reference DVL data:

[0025] After the inertial device zero-position estimation is performed by the velocity observation integrated navigation system, the total failure time of the DVL data should not exceed 10 minutes; otherwise, the estimation is considered a failure.

[0026] Among them, the failure of DVL data can be judged by the valid bits of DVL data and the consistency of DVL data before and after; if both conditions (1) and (2) in b) are met at the same time, the external reference information of DVL is considered to be valid; otherwise, the external reference information of DVL is determined to be invalid, and the zero-position estimation result of the inertial device is invalid.

[0027] c) No external reference validity criterion is set for the odometer; the odometer information is always valid by default.

[0028] Furthermore, the specific criteria in step 5 are as follows:

[0029] e) Determining the total time to enter integrated navigation state:

[0030] (3) For the position observation mode of the satellite navigation system, the total time of the integrated navigation state is greater than 3600s;

[0031] (4) For speed observation mode of integrated navigation system with DVL or odometer as the matching system, the total time of integrated navigation state is greater than 5400s;

[0032] f) Determining the positions of two valid linear motions and the change in heading:

[0033] (4) Determining the first position for direct flight:

[0034] If the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 40° within 20 consecutive minutes, it is determined that the first position straight flight has been completed, and the turning judgment from the first position to the second position is initiated.

[0035] (5) Turning judgment from the first position to the second position:

[0036] If the difference between the 1Hz heading value of the inertial navigation system and the average heading value of the first position is greater than 60° for 3 consecutive seconds, it is determined that the system has entered a turning state; if the difference between two adjacent 1Hz heading values ​​of the inertial navigation system is less than 0.2° for 10 consecutive seconds, it is determined that the system has completed the turn from the first position to the second position and has entered the straight-line judgment of the second position.

[0037] (6) Determining the second position for direct flight:

[0038] After completing the turn from the first position to the second position, for the position observation mode of the integrated navigation system with satellite navigation as the supporting system, if the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 120° within 40 minutes, and the difference between the average heading of the second position and the average heading of the first position is greater than 60°, then it is determined that the straight-line flight to the second position has been completed. For the speed observation mode of the integrated navigation system with DVL or odometer as the supporting system, if the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 120° within 1 hour, and the difference between the average heading of the second position and the average heading of the first position is greater than 60°, then it is determined that the straight-line flight to the second position has been completed.

[0039] If conditions (1), (2), and (3) in b) are met, then it is determined that the two valid linear motion position judgment and heading change judgment criteria are satisfied;

[0040] g) Accelerometer zero-position P-array determination:

[0041] Error variance matrix P in the Kalman filter of integrated navigation 15×15 Within the formation, the accelerometer x is at zero position ▽ x And the accelerometer y-zero position ▽ y If the root mean square of all diagonal elements of the corresponding dimension is not greater than 50 μg, then the accelerometer zero-position P-matrix criterion is satisfied, as shown in the following formula:

[0042]

[0043] h) Judgment of zero-point value estimation of accelerometer:

[0044] Zero-point estimates of accelerometer x and accelerometer y and If the absolute value is not greater than 5000 μg, then the accelerometer zero-point value criterion is met, as shown in the following formula:

[0045]

[0046] If all four judgment conditions (a), (b), (c), and (d) are met simultaneously, the accelerometer zero-point estimation for this group is deemed valid, and the accelerometer zero-point estimation can be executed. x and ▽ y Feedback compensation will be provided; otherwise, the accelerometer zero-point estimation will be deemed invalid, and the accelerometer zero-point estimation will not be performed. x and ▽ y Feedback and compensation.

[0047] Furthermore, the specific criteria in step 6 are as follows:

[0048] e) Determining the total time to enter integrated navigation state:

[0049] For the position observation mode of the integrated navigation system with satellite navigation as the supporting system or the speed observation mode of the integrated navigation system with DVL / odometer as the supporting system, the total time of the integrated navigation state is greater than 7200s.

[0050] f) Determining the positions of two valid linear motions and the change in heading:

[0051] (4) Determining the first position for direct flight:

[0052] If the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 40° within 20 consecutive minutes, it is determined that the first position straight flight has been completed, and the turning judgment from the first position to the second position is initiated.

[0053] (5) Turning judgment from the first position to the second position:

[0054] If the difference between the 1Hz heading value of the inertial navigation system and the average heading value of the first position is greater than 60° for 3 consecutive seconds, it is determined that the system has entered a turning state; if the difference between two adjacent 1Hz heading values ​​of the inertial navigation system is less than 0.2° for 10 consecutive seconds, it is determined that the system has completed the turn from the first position to the second position and has entered the straight-line judgment of the second position.

[0055] (6) Determining the second position for direct flight:

[0056] After completing the turn from the first position to the second position, for the position observation mode of the integrated navigation system with satellite navigation as the supporting system, if the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 120° within 1 hour, and the difference between the average heading of the second position and the average heading of the first position is greater than 60°, then it is determined that the straight-line flight to the second position has been completed. For the speed observation mode of the integrated navigation system with DVL or odometer as the supporting system, if the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 120° within 80 minutes, and the difference between the average heading of the second position and the average heading of the first position is greater than 60°, then it is determined that the straight-line flight to the second position has been completed.

[0057] If the three conditions (1), (2), and (3) in b) above are met, then it is determined that the two valid linear motion position judgment and heading change judgment criteria are met;

[0058] g) Determining the zero position of the gyroscope using the P-array:

[0059] Error variance matrix P in the Kalman filter of integrated navigation 15×15 Within the array, the gyroscope x zero position ε x And the gyroscope y zero position ε y If the root mean square of the diagonal elements of the corresponding dimension is not greater than 0.03° / h, then the gyroscope zero-position P-matrix criterion is satisfied, as shown in the following formula:

[0060]

[0061] h) Determining the zero-point value of the gyroscope estimation:

[0062] Zero-position estimates of gyroscope x and gyroscope y and If the absolute value is not greater than 0.2° / h, then the gyroscope zero-position criterion is met, as shown in the following formula:

[0063]

[0064] If all four judgment conditions (a), (b), (c), and (d) above are met, the zero-position estimation of the accelerometer in this group is deemed valid and feedback compensation can be performed; otherwise, the zero-position estimation of the gyroscope is deemed invalid.

[0065] The advantages and positive effects of this invention are as follows:

[0066] This invention addresses the typical combined navigation modes of inertial navigation systems (INS), namely satellite navigation combined with velocimeter navigation combined with velocimeter navigation. Combining the error principles of INS and the characteristics of combined navigation observation information, it proposes an adaptive zero-position estimation and compensation method for inertial devices compatible with multiple combined modes. This method adaptively judges the rationality of the zero-position estimation path and the validity of the zero-position estimation results, effectively solving the problem of adaptive zero-position estimation and compensation for INS devices. It enables online compensation for effectively estimated inertial device zero positions, improving the long-term navigation accuracy of INS. This method is applicable to various fields such as vehicle-mounted and ship-mounted systems, and is suitable for INS systems of different accuracy levels, demonstrating strong practicality and high engineering application value. Attached Figure Description

[0067] Figure 1 This is a flowchart of the process for inventing an adaptive zero-position estimation and compensation method for inertial devices in an inertial navigation system. Detailed Implementation

[0068] The structure of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that these embodiments are descriptive and not limiting.

[0069] For an adaptive estimation and compensation method for zero-position of inertial devices in an inertial navigation system, please refer to [link / reference]. Figure 1 Its inventive point is that it includes the following steps:

[0070] Step 1: Install the inertial navigation system (INS) on the vehicle or ship, and install its matching integrated navigation system (such as satellite navigation, DVL or odometer) on the test vehicle or ship according to its installation method, and complete the electrical connection between the INS and the corresponding integrated navigation system.

[0071] Step 2: Power on the inertial navigation system and the supporting integrated navigation system. The inertial navigation system completes the initial alignment (initial alignment methods such as vehicle static, vehicle dynamic, and ship mooring are all acceptable) and can output effective speed, position, and attitude information. The supporting integrated navigation system can output effective reference information, and any errors related to installation levers or time synchronization can be compensated in advance.

[0072] Step 3: The inertial navigation system enters the integrated navigation state, and the vehicle or ship can enter the driving or sailing state. Based on the information type of the supporting integrated navigation system, the corresponding mode is selected for inertial device zero-position estimation: if the supporting integrated navigation system is satellite navigation, the position combination mode is used for inertial device zero-position estimation; if the supporting integrated navigation system is odometry or DVL, the velocity combination mode is used for inertial device zero-position estimation. The inertial device zero-position estimation methods in position combination and velocity combination modes establish state equations and measurement equations based on the characteristics of inertial navigation and integrated information, and use the Kalman filtering method for inertial device zero-position estimation. The specific definition of the state variable X is shown in the following equation:

[0073]

[0074] in:

[0075] δV E δV N δV U These are the inertial navigation system's calculations for eastward, northward, and azimuthal velocity errors, respectively.

[0076] δL, δλ, and δh represent the latitude, longitude, and altitude errors in inertial navigation solutions, respectively.

[0077] φ E φ N φ U These are the attitude misalignment angles;

[0078] ε x ε y ε z This is the zero position of the gyroscope;

[0079] ▽ x 、▽ y 、▽ z This is the zero position of the accelerometer.

[0080] The state equation for zero-position estimation of inertial devices is shown below:

[0081]

[0082] The equation for zero-position estimation of inertial devices is shown below:

[0083] Z p =H p X+V (3)

[0084] Z v =H v X+V

[0085] Among them: (3) The above equation is the position observation mode measurement equation of the supporting integrated navigation system as satellite navigation, and (3) The below equation is the speed observation mode measurement equation of the supporting integrated navigation system as DVL or odometer.

[0086] The error models of the inertial navigation system established by equations (2) and (3) are commonly used models in the field of inertial navigation, and will not be elaborated here. The Kalman filtering method is used on the above error models to estimate the zero position of the inertial devices in real time online.

[0087] Step 4: During the inertial device zero-position estimation process in the integrated navigation state, the validity of the external reference information of the supporting integrated navigation system is constantly judged. If the external reference information is deemed invalid, the zero-position estimation result of this group of inertial devices is considered invalid, and no compensation is made for the inertial device zero-position. If the external reference information is deemed valid, proceed to Step 5 to judge the validity of the accelerometer zero-position estimation and then proceed to Step 6 to judge the validity of the gyroscope zero-position estimation. Based on the characteristics of different external reference information, different validity criteria are designed as follows:

[0088] e) Criteria for determining the validity of external reference information for satellite navigation systems in conjunction with integrated navigation systems

[0089] (5) Determination of single consecutive failure time of external reference satellite guidance data:

[0090] After the inertial device zero-position estimation is performed by the initial position observation integrated navigation system, the single continuous failure time of the satellite navigation data should not exceed 1 minute; otherwise, it is determined that the estimation has failed.

[0091] (6) Determination of total failure time of external reference satellite navigation data:

[0092] After the inertial device zero-position estimation is performed by the initial position observation integrated navigation system, the total failure time of the satellite navigation data shall not exceed 10 minutes; otherwise, the estimation shall be deemed a failure.

[0093] The failure of satellite navigation data can be determined by checking the validity of the satellite navigation data, the consistency of the satellite navigation data, and the consistency between the satellite navigation position and the inertial navigation position. If both conditions (1) and (2) above are met, the external reference information of the satellite navigation is considered valid; otherwise, the external reference information of the satellite navigation is considered invalid, and the zero-position estimation result of the inertial device is invalid.

[0094] f) Criteria for determining the validity of external reference information in the integrated navigation system for DVL

[0095] (5) Determination of single consecutive failure time of external reference DVL data:

[0096] After the inertial device zero-position estimation is performed by the speed observation integrated navigation system, the single continuous failure time of the DVL data should not exceed 1 minute; otherwise, it is determined that the estimation has failed.

[0097] (6) Determining the total failure time of external reference DVL data:

[0098] After the inertial device zero-position estimation is performed by the velocity observation integrated navigation system, the total failure time of the DVL data should not exceed 10 minutes; otherwise, the estimation is considered a failure.

[0099] The invalidity of DVL data can be determined by checking the valid bits of DVL data and the consistency of DVL data. If both conditions (1) and (2) above are met, the external reference information of DVL is considered valid; otherwise, the external reference information of DVL is considered invalid, and the zero-position estimation result of the inertial device is invalid.

[0100] g) Criteria for determining the validity of external reference information for the odometer in the integrated navigation system

[0101] The odometer is mounted on the vehicle's drive shaft to measure the vehicle's mileage. It is less affected by external interference, so no external reference validity criterion is set for the odometer, and the odometer information is always valid by default.

[0102] Step 5: If the external reference information validity criterion from Step 4 is met during the inertial device zero-position estimation process in the integrated navigation state, then the validity of the accelerometer zero-position estimation is determined. The specific criteria are as follows:

[0103] i) Determining the total time to enter integrated navigation state:

[0104] (5) For the position observation mode of the satellite navigation system, the total time of the integrated navigation status is greater than 3600s.

[0105] (1h);

[0106] (6) For speed observation mode of DVL or odometer-based integrated navigation system, the total time of integrated navigation state is greater than 5400s (1.5h).

[0107] j) Determining the positions of two valid linear motions and the change in heading:

[0108] (7) First position direct flight determination:

[0109] If the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 40° within 20 consecutive minutes, it is determined that the first position straight flight has been completed, and the turning judgment from the first position to the second position is initiated.

[0110] (8) Turning judgment from the first position to the second position:

[0111] If the difference between the 1Hz heading value of the inertial navigation system and the average heading value of the first position is greater than 60° for 3 consecutive seconds, it is determined that the system has entered a turning state; if the difference between two adjacent 1Hz heading values ​​of the inertial navigation system is less than 0.2° for 10 consecutive seconds, it is determined that the system has completed the turn from the first position to the second position and has entered the straight-line judgment of the second position.

[0112] (9) Determining the second position for direct flight:

[0113] After completing the turn from the first position to the second position, for the position observation mode of the integrated navigation system with satellite navigation as the supporting system, if the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 120° within 40 minutes, and the difference between the average heading of the second position and the average heading of the first position is greater than 60°, then it is determined that the straight-line flight to the second position has been completed. For the speed observation mode of the integrated navigation system with DVL or odometer as the supporting system, if the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 120° within 1 hour, and the difference between the average heading of the second position and the average heading of the first position is greater than 60°, then it is determined that the straight-line flight to the second position has been completed.

[0114] If the above three conditions (1), (2), and (3) are met, then it is determined that the two valid linear motion position judgment and heading change judgment criteria are satisfied.

[0115] k) Accelerometer zero-position P-array determination:

[0116] Error variance matrix P in the Kalman filter of integrated navigation 15×15 Within the formation, the accelerometer x is at zero position ▽ x And the accelerometer y-zero position ▽ y If the root mean square of the diagonal elements of the corresponding dimension is not greater than 50μg, then the accelerometer zero-position P-matrix criterion is satisfied, as shown in the following formula. The variance threshold of the accelerometer zero-position estimation error should be adjusted according to the accelerometer accuracy of the inertial navigation system used.

[0117]

[0118] l) Judgment of zero-point value estimation by accelerometer:

[0119] Zero-point estimates of accelerometer x and accelerometer y and If the absolute value is not greater than 5000μg, then the accelerometer zero-point value criterion is met, as shown in the following formula. The absolute value threshold of the accelerometer zero-point estimate should be adjusted according to the accelerometer accuracy of the inertial navigation system used.

[0120]

[0121] If all four judgment conditions (a), (b), (c), and (d) are met simultaneously, the accelerometer zero-point estimation for this group is deemed valid, and the accelerometer zero-point estimation can be executed. x and ▽ yFeedback compensation can be performed using common methods for inertial navigation system error estimation feedback, which will not be elaborated here; otherwise, the accelerometer zero-point estimation is deemed invalid, and the accelerometer zero-point estimation is not executed. x and ▽ y Feedback and compensation.

[0122] Step 6: If the external reference information validity criterion from Step 4 is satisfied during the inertial device zero-position estimation process in the integrated navigation state, then the validity of the gyroscope zero-position estimation is determined. The specific criteria are as follows:

[0123] i) Determining the total time to enter integrated navigation state:

[0124] For position observation mode with satellite navigation as a supporting integrated navigation system or speed observation mode with DVL / odometer as a supporting integrated navigation system, the total time of integrated navigation status is greater than 7200s (2h).

[0125] j) Determining the positions of two valid linear motions and the change in heading:

[0126] (7) First position direct flight determination:

[0127] If the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 40° within 20 consecutive minutes, it is determined that the first position straight flight has been completed, and the turning judgment from the first position to the second position is initiated.

[0128] (8) Turning judgment from the first position to the second position:

[0129] If the difference between the 1Hz heading value of the inertial navigation system and the average heading value of the first position is greater than 60° for 3 consecutive seconds, it is determined that the system has entered a turning state; if the difference between two adjacent 1Hz heading values ​​of the inertial navigation system is less than 0.2° for 10 consecutive seconds, it is determined that the system has completed the turn from the first position to the second position and has entered the straight-line judgment of the second position.

[0130] (9) Determining the second position for direct flight:

[0131] After completing the turn from the first position to the second position, for the position observation mode of the integrated navigation system with satellite navigation as the supporting system, if the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 120° within 1 hour, and the difference between the average heading of the second position and the average heading of the first position is greater than 60°, then it is determined that the straight-line flight to the second position has been completed. For the speed observation mode of the integrated navigation system with DVL or odometer as the supporting system, if the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 120° within 80 minutes, and the difference between the average heading of the second position and the average heading of the first position is greater than 60°, then it is determined that the straight-line flight to the second position has been completed.

[0132] If the above three conditions (1), (2), and (3) are met, then it is determined that the two valid linear motion position judgment and heading change judgment criteria are satisfied.

[0133] k) Gyroscope zero-position P-array determination:

[0134] Error variance matrix P in the Kalman filter of integrated navigation 15×15 Within the array, the gyroscope x zero position ε x And the gyroscope y zero position ε y If the root mean square of the diagonal elements of the corresponding dimension is not greater than 0.03° / h, then the gyroscope zero-position P-matrix criterion is satisfied, as shown in the following formula. The variance threshold of this gyroscope zero-position estimation error should be adjusted according to the gyroscope accuracy of the inertial navigation system used.

[0135]

[0136] l) Determining the zero-point value of the gyroscope estimation:

[0137] Zero-position estimates of gyroscope x and gyroscope y and If the absolute value is not greater than 0.2° / h, then the gyroscope zero-position numerical criterion is met, as shown in the following formula (the absolute value threshold of this gyroscope zero-position estimate should be adjusted according to the gyroscope accuracy of the inertial navigation system used).

[0138]

[0139] If all four judgment conditions (a), (b), (c), and (d) above are met, the zero-position estimation of the accelerometer in this group is deemed valid and feedback compensation can be performed. This feedback compensation can adopt the general means of error estimation feedback for inertial navigation systems, which will not be elaborated here. Otherwise, the zero-position estimation of the gyroscope is deemed invalid.

[0140] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A method for adaptive zero-position estimation and compensation of inertial devices in an inertial navigation system, characterized in that, Includes the following steps: Step 1: Install the inertial navigation system on the vehicle or ship, and install its matching integrated navigation system on the test vehicle or ship according to its installation method, and complete the electrical connection between the inertial navigation system and the corresponding integrated navigation system. Step 2: Power on the inertial navigation system and its integrated navigation system to complete the initial alignment of the inertial navigation system, ensuring that the inertial navigation system can output effective velocity, position and attitude information, and that the integrated navigation system can output effective reference information; Step 3: The inertial navigation system enters the integrated navigation state, and the vehicle or ship enters the driving or sailing state; according to the information type of the supporting integrated navigation system, select the corresponding mode to perform zero-position estimation of the integrated navigation inertial devices; Step 4: During the zero-position estimation of inertial devices in the integrated navigation state, the validity of the external reference information of the supporting integrated navigation system is always judged. If the validity of the external reference information is invalid, the zero-position estimation result of this group of inertial devices is judged to be invalid, and the zero position of the inertial devices is not compensated. If the external reference information is deemed valid, proceed to step 5 to determine the validity of the accelerometer zero-point estimation and then proceed to step 6 to determine the validity of the gyroscope zero-point estimation. Based on the characteristics of different external reference information, different validity criteria are designed as follows: a) The validity criterion for the external reference information of the satellite navigation system in the supporting integrated navigation system is: (1) Determination of single consecutive failure time of external reference satellite navigation data: After the inertial device zero-position estimation is performed by the initial position observation integrated navigation system, the single continuous failure time of the satellite navigation data should not exceed 1 minute; otherwise, it is determined that the estimation has failed. (2) Determination of total failure time of external reference satellite navigation data: After the inertial device zero-position estimation is performed by the initial position observation integrated navigation system, the total failure time of the satellite navigation data shall not exceed 10 minutes; otherwise, the estimation shall be deemed a failure. Among them, the failure of satellite navigation data is judged by the valid position of satellite navigation data, the consistency of satellite navigation data before and after, and the consistency between satellite navigation position and inertial navigation position. If both conditions (1) and (2) in a) are met at the same time, the external reference information of satellite navigation is considered to be valid; otherwise, the external reference information of satellite navigation is determined to be invalid, and the zero position estimation result of the inertial device is invalid. Step 5: Determine the validity of the accelerometer zero-point estimation based on the set criteria; Step 6: Determine the validity of the gyroscope zero-position estimation based on the set criteria.

2. The method for adaptive zero-position estimation and compensation of inertial devices in an inertial navigation system according to claim 1, characterized in that: In step 3, if the supporting integrated navigation system is satellite navigation, the system enters the position combination mode to perform inertial device zero-position estimation; if the supporting integrated navigation system is odometry or DVL, the system enters the velocity combination mode to perform inertial device zero-position estimation. The inertial device zero-position estimation methods in the position combination and velocity combination modes establish state equations and measurement equations based on the characteristics of inertial navigation and integrated information, and use the Kalman filtering method to perform inertial device zero-position estimation.

3. The method for adaptive zero-position estimation and compensation of inertial devices in an inertial navigation system according to claim 2, characterized in that, Step 4 also includes: b) Criteria for determining the validity of external reference information in the integrated navigation system for DVL (1) Determination of single consecutive failure time of external reference DVL data: After the inertial device zero-position estimation is performed by the speed observation integrated navigation system, the single continuous failure time of the DVL data should not exceed 1 minute; otherwise, it is determined that the estimation has failed. (2) Determination of total failure time of external reference DVL data: After the inertial device zero-position estimation is performed by the velocity observation integrated navigation system, the total failure time of the DVL data should not exceed 10 minutes; otherwise, the estimation is considered a failure. Among them, the failure of DVL data is judged by the valid bits of DVL data and the consistency of DVL data before and after; if both conditions (1) and (2) in b) are met at the same time, the external reference information of DVL is considered to be valid; otherwise, the external reference information of DVL is determined to be invalid, and the zero-position estimation result of the inertial device is invalid. c) No external reference validity criterion is set for the odometer; the odometer information is always valid by default.

4. The method for adaptive zero-position estimation and compensation of inertial devices in an inertial navigation system according to claim 1, characterized in that, In step 5, the specific criteria are as follows: a) Determining the total time to enter integrated navigation state: (1) For the position observation mode of the satellite navigation system, the total time of the integrated navigation state is greater than 3600s; (2) For speed observation mode of DVL or odometry-equipped integrated navigation system, the total time of integrated navigation state is greater than 5400s. b) Determining the positions of two valid linear motions and the change in heading: (1) Determining the first position for direct flight: If the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 40° within 20 consecutive minutes, it is determined that the first position straight flight has been completed, and the turning judgment from the first position to the second position is initiated. (2) Turning judgment from the first position to the second position: If the difference between the 1Hz heading value of the inertial navigation system and the average heading value of the first position is greater than 60° for 3 consecutive seconds, it is determined that the system has entered a turning state; if the difference between two adjacent 1Hz heading values ​​of the inertial navigation system is less than 0.2° for 10 consecutive seconds, it is determined that the system has completed the turn from the first position to the second position and has entered the straight-line judgment of the second position. (3) Determining the second position for direct flight: After completing the turn from the first position to the second position, for the position observation mode of the integrated navigation system with satellite navigation as the supporting system, if the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 120° within 40 minutes, and the difference between the average heading value of the second position and the average heading value of the first position is greater than 60°, then it is determined that the straight-line flight to the second position has been completed; for the speed observation mode of the integrated navigation system with DVL or odometer as the supporting system, if the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 120° within 1 hour, and the difference between the average heading value of the second position and the average heading value of the first position is greater than 60°, then it is determined that the straight-line flight to the second position has been completed. If conditions (1), (2), and (3) in b) are met, then it is determined that the two valid linear motion position judgment and heading change judgment criteria are satisfied; c) Accelerometer zero-position P-array determination: Error variance matrix P in the Kalman filter of integrated navigation 15×15 Within the array, accelerometer x zero position and accelerometer y-zero position If the root mean square of all diagonal elements of the corresponding dimension is not greater than 50 μg, then the accelerometer zero-position P-matrix criterion is satisfied, as shown in the following formula: d) Judgment of accelerometer zero-point estimation: Zero-point estimates of accelerometer x and accelerometer y and If the absolute value is not greater than 5000 μg, then the accelerometer zero-point value criterion is met, as shown in the following formula: If all four judgment conditions (a), (b), (c), and (d) above are met simultaneously, the accelerometer zero-point estimation for this group is deemed valid, and the accelerometer zero-point estimation is executed. and Feedback compensation will be provided; otherwise, the accelerometer zero-point estimation will be deemed invalid, and the accelerometer zero-point estimation will not be performed. and Feedback and compensation.

5. The method for adaptive zero-position estimation and compensation of inertial devices in an inertial navigation system according to claim 1, characterized in that: In step 6, the specific criteria are as follows: a) Determining the total time to enter integrated navigation state: For the position observation mode of the integrated navigation system with satellite navigation as the supporting system or the speed observation mode of the integrated navigation system with DVL / odometer as the supporting system, the total time of the integrated navigation state is greater than 7200s. b) Determining the positions of two valid linear motions and the change in heading: (1) Determining the first position for direct flight: If the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 40° within 20 consecutive minutes, it is determined that the first position straight flight has been completed, and the turning judgment from the first position to the second position is initiated. (2) Turning judgment from the first position to the second position: If the difference between the 1Hz heading value of the inertial navigation system and the average heading value of the first position is greater than 60° for 3 consecutive seconds, it is determined that the system has entered a turning state; if the difference between two adjacent 1Hz heading values ​​of the inertial navigation system is less than 0.2° for 10 consecutive seconds, it is determined that the system has completed the turn from the first position to the second position and has entered the straight-line judgment of the second position. (3) Determining the second position for direct flight: After completing the turn from the first position to the second position, for the position observation mode of the integrated navigation system with satellite navigation as the supporting system, if the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 120° within 1 hour, and the difference between the average heading value of the second position and the average heading value of the first position is greater than 60°, then it is determined that the straight-line flight to the second position has been completed; for the speed observation mode of the integrated navigation system with DVL or odometer as the supporting system, if the difference between the maximum and minimum values ​​of the inertial navigation headings is less than 120° within 80 minutes, and the difference between the average heading value of the second position and the average heading value of the first position is greater than 60°, then it is determined that the straight-line flight to the second position has been completed. If the three conditions (1), (2), and (3) in b) above are met, then it is determined that the two valid linear motion position judgment and heading change judgment criteria are met; c) Determining the zero position of the gyroscope using the P-array: Error variance matrix P in the Kalman filter of integrated navigation 15×15 Within the array, the gyroscope x zero position ε x And the gyroscope y zero position ε y If the root mean square of the diagonal elements of the corresponding dimension is not greater than 0.03° / h, then the gyroscope zero-position P-matrix criterion is satisfied, as shown in the following formula: d) Determining the zero-point value of the gyroscope estimation: Zero-position estimates of gyroscope x and gyroscope y and If the absolute value is not greater than 0.2° / h, then the gyroscope zero-position criterion is met, as shown in the following formula: If all four judgment conditions (a), (b), (c), and (d) are met simultaneously, the accelerometer zero-position estimation of this group is deemed valid, and feedback compensation is executed; otherwise, the gyroscope zero-position estimation is deemed invalid.

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