Method, system, equipment and medium for initial alignment of dynamic base based on variable integral length

Abstract

The present invention discloses a method, system, device, and medium for initial alignment of a moving base based on a variable integral length. The method comprises the following steps: acquiring inertial sensor data and satellite navigation receiver data; constructing a variable integral length vector observer model and discretizing the observer model to obtain a discretized reference vector and a discretized observation vector; constructing an OBA attitude matrix based on the discretized reference vector and the discretized observation vector to perform attitude estimation; and performing calibration based on the attitude estimation value, repeating the above steps until a set calibration time is reached. While calculating the vector observer, the present invention uses a variable integral length method to reduce the influence of past vectors on the alignment results, thereby optimizing the alignment process and solving the problem of errors changing with carrier maneuvers during the moving base alignment process.

Description

Technical Field

[0001] The present invention relates to the field of initial alignment of inertial navigation systems, and belongs to a method, system, device and medium for initial alignment of a moving base based on variable integral length. Background Art

[0002] In the field of moving base alignment, it is a relatively common method to use a satellite navigation system to assist an inertial navigation system for moving base alignment. Through the chain rule of the direction cosine matrix, the alignment problem can be transformed into a vector observer attitude estimation problem. The construction of the vector observer uses the sensor output for iterative calculation. However, since the alignment error is related to the mapping of the sensor zero bias in the navigation system, when the carrier maneuvers, its alignment error will show a fluctuating characteristic with the maneuver change.

[0003] To overcome the problem that the alignment error of the traditional method is affected by the carrier maneuvering movement, it is of great significance to propose a new method for initial alignment of a moving base. Summary of the Invention

[0004] The purpose of the present invention is to provide a method, system, device and medium for initial alignment of a moving base based on variable integral length, which weakens the influence of the carrier maneuvering movement on the alignment error, realizes the optimization of the dynamic alignment process, and improves the alignment accuracy.

[0005] The technical solution for achieving the purpose of the present invention is as follows:

[0006] A method for aligning a moving base based on variable integral length includes the following steps:

[0007] Step 1: Obtain inertial sensor data and satellite navigation receiver data;

[0008] Step 2: Construct a variable integral length vector observer model;

[0009] Step 3: Design an OBA attitude estimation algorithm to achieve real-time attitude estimation;

[0010] Step 4: If the current alignment time k = M, output the alignment result and complete the alignment process, where M is the set duration of the alignment process. If k < M, it means the alignment process is not completed, then repeat the above steps 1 to 4 until the alignment ends.

[0011] An initial velocity perturbation elimination polar region moving base alignment system includes a data acquisition unit, an observer model construction unit, a discretization unit, an attitude estimation unit and a calibration unit; where:

[0012] The data acquisition unit is used to obtain inertial sensor data and satellite navigation receiver data;

[0013] The observer model construction unit is used to construct a variable integral length vector observer model;

[0014] The discretization unit is used to discretize the observer model to obtain a discretized reference vector and a discretized observation vector;

[0015] The attitude estimation unit performs attitude estimation through the OBA attitude matrix;

[0016] The calibration unit is calibrated using the pose estimation value.

[0017] A polar region moving base alignment device for eliminating initial velocity disturbances comprises: a memory, a processor and a computer program stored in the memory, wherein the polar region moving base alignment method for eliminating initial velocity disturbances is implemented when the processor executes the computer program.

[0018] A computer storage medium stores an executable program, and the executable program is executed by a processor to implement the steps of the polar region moving base alignment method for eliminating initial velocity disturbance.

[0019] The advantages of the present invention are:

[0020] (1) The present invention uses satellite navigation information to construct a vector observer, which has the advantage of high alignment accuracy;

[0021] (2) The present invention adopts the variable integral length method for vector optimization, which reduces the alignment error fluctuation caused by the maneuvering motion of the carrier and improves the alignment accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Flowchart of the alignment process of the present invention.

[0023] Figure 2 is a graph of variable integral length.

[0024] Figure 3 is the pitch angle error diagram.

[0025] Figure 4 is the roll angle error diagram.

[0026] Figure 5 is the heading angle error diagram. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and implementation examples:

[0028] The present invention proposes a dynamic base initial alignment method based on variable integral length. While calculating the vector observer, the variable integral length method is used to reduce the influence of the past vector on the alignment result, thereby optimizing the alignment process. Figure 1As shown, it specifically includes the following steps:

[0029] Step 1: Obtain inertial sensor data and satellite navigation receiver data;

[0030] When aligning the dynamic base, it is necessary to collect sensor data. Considering the inconsistency between the inertial sensor and the satellite receiver data output, the inertial sensor data is collected first:

[0031]

[0032] Where, f b Indicates true comparison; b a Indicates the accelerometer zero bias; η a represents the accelerometer random noise; Indicates the specific force measured by the accelerometer; represents the true angular velocity; b g Indicates the gyroscope bias; η g represents the gyroscope random noise; Indicates the angular velocity measured by the gyroscope; where the gyroscope measurement constant drift error is b g =[0.02 0.02 0.02] T ° / h, the random walk error measured by the gyroscope is The output frequency is 200Hz; the accelerometer measurement constant drift error is b a =[500 500 500] T μg, the random walk error of the accelerometer is The output frequency is 200Hz; the sampling period of the satellite navigation system is 1s.

[0033] When satellite data is not obtained, the acceleration increment and angular velocity increment are calculated using inertial sensor data:

[0034]

[0035] 8Δθ1×Δv2+2Δv1×Δθ i +2Δθ2xΔv2)

[0036]

[0037] Where, Indicates position increment; represents the velocity increment; Δv1 represents the specific force sample 1; Δv2 represents the specific force sample 2; Δθ1 represents the rotation sample 1; Δθ2 represents the rotation sample 2; Δv1, Δv2, Δθ1, and Δθ2 are the integrals of the two inertial sensor data, respectively. The integral formulas are well known in the art and will not be repeated here.

[0038] When satellite data is valid, you can obtain satellite positioning information:

[0039]

[0040] Where, Indicates satellite output position information; p n Indicates the real position information; δp n Indicates position error; Indicates the satellite output speed information; v n Indicates true speed information; δv n Indicates speed error;

[0041] Step 2: Construct a variable integral length vector observer model;

[0042] After acquiring the inertial sensor and satellite navigation data, combined with Figure 2 The variable integral length alignment diagram shown in the figure can then be used to construct the following vector observer:

[0043]

[0044] Where, f b Indicates the specific force measured by the accelerometer; Represents the direction cosine matrix of the load system relative to the initial load system at time σ; represents the reference vector; represents the distance differential; represents the observation vector, Represents the direction cosine matrix of the navigation system at time τ relative to the initial navigation system; Represents the mapping of the Earth's rotational angular velocity in the navigation system; v n represents the navigation system speed; S represents the number of vectors in the window; Δt G Indicates the data sampling period of the satellite navigation receiver; v n (t m ) represents t m Time navigation system speed; g n represents the earth's gravity; t m Indicates the starting time of the integration process; t M Indicates the end time of the integration process;

[0045] By discretizing the above formula, the reference vector can be obtained as follows:

[0046]

[0047] Where, represents the discretized reference vector; Indicates the speed increment; Indicates position increment; Δt GIndicates the data sampling period of the satellite navigation receiver; Indicates t s Direction cosine matrix of the load system relative to the initial load system at time t; Indicates t k Direction cosine matrix of the load system relative to the initial load system at time t;

[0048] Similarly, the discretized observation vector can be expressed as:

[0049]

[0050] Where, represents the discretized observation vector; r n (t M ) represents t M Momentary movement distance; r n (t m ) represents t M Movement distance at any moment; Indicates t M The direction cosine matrix of the moment navigation system relative to the initial navigation system; Indicates t m The direction cosine matrix of the moment navigation system relative to the initial navigation system; S represents the number of vectors in the window; v n (t M ) represents t M Navigation system speed at time; Δt G Indicates the data sampling period of the satellite navigation receiver; Indicates t s The direction cosine matrix of the moment navigation system relative to the initial navigation system; Represents the mapping of the angular velocity of the navigation system relative to the inertial system in the navigation system; Represents the mapping of the Earth's rotational angular velocity in the navigation system; r n (t s+1 ) represents t s+1 Distance traveled at a moment; g n Represents the Earth's gravity; Indicates t s The direction cosine matrix of the moment navigation system relative to the initial navigation system; Indicates t k The direction cosine matrix of the moment navigation system relative to the initial navigation system;

[0051] pass Figure 2 As can be seen from the variable integral length alignment diagram, this method performs alignment within the selected integral interval, eliminating the cumulative error.

[0052] Step 3: Design an OBA pose estimation algorithm to achieve real-time pose estimation;

[0053] Using the vectors constructed above, the following OBA attitude matrix can be constructed:

[0054]

[0055] Where K M represents the OBA posture matrix at time M; K M-1 Represents the OBA posture matrix at time M-1; represents the discretized reference vector; represents the discretized observation vector;

[0056] The matrix operation can be expressed as:

[0057]

[0058] Where, represents the discretized reference vector; represents the discretized observation vector;

[0059] A polar region moving base alignment system for eliminating initial velocity disturbances comprises a data acquisition unit, an observer model construction unit, a discretization unit, an attitude estimation unit, and a calibration unit; wherein:

[0060] The data acquisition unit is used to acquire inertial sensor data and satellite navigation receiver data;

[0061] The observer model construction unit is used to construct a variable integral length vector observer model;

[0062] The discretization unit is used to discretize the observer model to obtain a discretized reference vector and a discretized observation vector;

[0063] The attitude estimation unit performs attitude estimation through the OBA attitude matrix;

[0064] The calibration unit is calibrated using the pose estimation value.

[0065] The system includes technical features of the dynamic base initial alignment method based on variable integral length, which will not be repeated here.

[0066] Based on the verification method, Figures 3 to 5 This is a diagram showing the alignment results of the pitch angle, roll angle, and heading angle of the present invention and the traditional method. It can be seen from the diagram that the present method can effectively suppress error fluctuations and improve alignment accuracy.

Claims

1. A method for initial alignment of a dynamic base with variable integral length, characterized in that: It includes the following steps: Acquire inertial sensor data and satellite navigation receiver data; Constructing a variable integral length vector observer model, and discretizing the observer model to obtain a discretized reference vector and a discretized observation vector; Construct the OBA attitude matrix based on the discretized reference vector and the discretized observation vector to perform attitude estimation; Calibrate based on the estimated attitude value and repeat the above steps until the set calibration time is reached; The variable integral length vector observer model is: Where, f b Indicates the specific force measured by the accelerometer; Represents the direction cosine matrix of the load system relative to the initial load system at time σ; represents the reference vector; represents the distance differential; represents the observation vector, Represents the direction cosine matrix of the navigation system at time τ relative to the initial navigation system; Represents the mapping of the Earth's rotational angular velocity in the navigation system; v n represents the navigation system speed; S represents the number of vectors in the window; Δt G Indicates the satellite navigation receiver data sampling period; v n (t m ) represents t m Time navigation system speed; g n Represents the Earth's gravity; t m Indicates the starting time of the integration process; t M Indicates the end time of the integration process.

2. The method for initial alignment of a dynamic base with variable integral length according to claim 1, characterized in that: The discretized reference vector is: Where, represents the discretized reference vector; Indicates the speed increment; Indicates position increment; Δt G Indicates the data sampling period of the satellite navigation receiver; Indicates t s Direction cosine matrix of the load system relative to the initial load system at time t; Indicates t k The direction cosine matrix of the load system at time t relative to the initial load system.

3. The method for initial alignment of a dynamic base with variable integral length according to claim 2, characterized in that: The speed increment and position increments It is determined by calculation using inertial sensor data, specifically: Where Δv1 and Δν2 represent the specific force samples corresponding to the two inertial sensors; Δθ1 and Δθ2 represent the rotation samples corresponding to the two inertial sensors.

4. The method for initial alignment of a dynamic base with variable integral length according to claim 1, characterized in that: The discretized observation vector is: Where, represents the discretized observation vector; r n (t M ) represents t M Momentary movement distance; r n (t m ) represents t m Distance traveled at any moment; Indicates t M The direction cosine matrix of the moment navigation system relative to the initial navigation system; Indicates t m The direction cosine matrix of the moment navigation system relative to the initial navigation system; S represents the number of vectors in the window; v n (t M ) represents t M Navigation system speed at time; Δt G Indicates the data sampling period of the satellite navigation receiver; Indicates t s The direction cosine matrix of the moment navigation system relative to the initial navigation system; Represents the mapping of the angular velocity of the navigation system relative to the inertial system in the navigation system; Represents the mapping of the Earth's rotational angular velocity in the navigation system; r n (t s+1 ) represents t s+1 Movement distance at a moment; g n Represents the Earth's gravity; Indicates t s The direction cosine matrix of the moment navigation system relative to the initial navigation system; Indicates t k The direction cosine matrix of the moment navigation system relative to the initial navigation system.

5. The method for initial alignment of a dynamic base with variable integral length according to claim 1, characterized in that: The OBA attitude matrix is: Where K M represents the OBA posture matrix at time M; K M-1 Represents the OBA posture matrix at time M-1; represents the discretized reference vector; represents the discretized observation vector; The matrix operation is: Where, represents the discretized reference vector; represents the discretized observation vector.

6. The method for initial alignment of a dynamic base with variable integral length according to claim 1, characterized in that: The set calibration time is 600s.

7. A dynamic base initial alignment system with variable integral length, characterized in that: It includes a data acquisition unit, an observer model building unit, a discretization unit, a posture estimation unit and a calibration unit; wherein: The data acquisition unit is used to acquire inertial sensor data and satellite navigation receiver data; The observer model construction unit is used to construct a variable integral length vector observer model; The discretization unit is used to discretize the observer model to obtain a discretized reference vector and a discretized observation vector; The attitude estimation unit performs attitude estimation through the OBA attitude matrix; The calibration unit is calibrated using the pose estimation value; The variable integral length vector observer model is: Where, f b Indicates the specific force measured by the accelerometer; Represents the direction cosine matrix of the load system relative to the initial load system at time σ; represents the reference vector; represents the distance differential; represents the observation vector, Represents the direction cosine matrix of the navigation system at time τ relative to the initial navigation system; Represents the mapping of the Earth's rotational angular velocity in the navigation system; v n represents the navigation system speed; S represents the number of vectors in the window; Δt G Indicates the satellite navigation receiver data sampling period; v n (t m ) represents t m Time navigation system speed; g n represents the earth's gravity; t m Indicates the starting time of the integration process; t M Indicates the end time of the integration process.

8. A dynamic base initial alignment device with variable integral length, characterized in that: include: A memory, a processor and a computer program stored in the memory, wherein when the processor executes the computer program, the method for initial alignment of a moving base with a variable integral length as described in any one of claims 1 to 6 is implemented.

9. A computer storage medium, characterized in that The computer storage medium stores an executable program, and the executable program is executed by a processor to implement the steps of the method for initial alignment of a dynamic base with a variable integral length as described in any one of claims 1 to 6.

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