A method and device for tightly coupled land integrated navigation, computer equipment and medium

Abstract

The application belongs to the technical field of integrated navigation, and relates to a tightly coupled land integrated navigation method, device, computer equipment and medium. The method comprises the following steps: obtaining related parameters of a two-dimensional laser Doppler velocimeter, and obtaining a conversion matrix of a two-dimensional laser Doppler velocimeter coordinate system and a beam coordinate system; obtaining an output speed of a strapdown inertial navigation system in a navigation coordinate system, and obtaining an output speed of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system; obtaining an output speed of the strapdown inertial navigation system in the beam coordinate system according to the conversion matrix and the output speed of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system; constructing a Kalman filter, taking a difference between the output speed of the strapdown inertial navigation system in the beam coordinate system and a speed of the two-dimensional laser Doppler velocimeter in the beam direction as a filter observation, estimating a state vector of the integrated navigation system, and navigating. The method improves the robustness of the integrated navigation system.

Description

Technical Field

[0001] This application relates to the field of integrated navigation technology, and in particular to a tightly coupled land integrated navigation method, apparatus, computer equipment, and medium. Background Technology

[0002] Integrated navigation systems require the fusion of information from multiple sensors to leverage the strengths of each sensor. In the field of land-based integrated navigation, the most widely used auxiliary sensors are the Global Positioning System (GPS) and odometers. While GPS can directly provide accurate speed and position information, it suffers from signal instability, poor anti-interference capabilities, and susceptibility to signal blockage by trees and buildings. In contrast, odometers are completely autonomous, providing speed and displacement increment information in the vehicle's coordinate system. However, the accuracy of odometer measurements is closely related to the vehicle's driving conditions and the condition of its wheels. Wheel temperature, air pressure, wear, and bouncing or slipping during vehicle operation all reduce the accuracy of odometer measurements.

[0003] In existing technologies, one-dimensional laser Doppler velocimeters can be used. These velocimeters are a novel type of speed sensor, entirely domestically developed, and offer advantages such as non-contact measurement, high spatial resolution, fast dynamic response, wide velocity range, and high directional sensitivity. In recent years, they have been used on a small scale in land-based integrated navigation systems with satisfactory results. However, like odometers, one-dimensional laser Doppler velocimeters can only provide the forward velocity of the vehicle. This makes the integrated navigation system, which combines a one-dimensional laser Doppler velocimeter with a strapdown inertial navigation system, less than ideal for estimating the vehicle's altitude.

[0004] Therefore, a two-dimensional laser Doppler velocimeter can be used. The two-dimensional laser Doppler velocimeter has two beams and can obtain the forward and upward velocities of the vehicle based on these two beams. This will enable the integrated navigation system to achieve higher positioning accuracy, especially in terms of altitude.

[0005] However, in a combined navigation system consisting of a two-dimensional laser Doppler velocimeter and a strapdown inertial navigation system, directly using the two-dimensional velocity obtained from the two-dimensional laser Doppler velocimeter is a loosely coupled approach. This requires that the signals measured by both beams of the two-dimensional laser Doppler velocimeter be valid. If only one beam signal from the two-dimensional laser Doppler velocimeter is normal, the loosely coupled combined navigation system will not function properly, and navigation errors will accumulate rapidly. Summary of the Invention

[0006] Based on this, it is necessary to provide a tightly coupled land-based integrated navigation method, device, computer equipment, and medium to address the aforementioned technical problems. This allows the integrated navigation system to continue operating normally even when one of the beam signals of the two-dimensional laser Doppler velocimeter fails, greatly improving the robustness of the integrated navigation system.

[0007] A tightly coupled land-based integrated navigation method, comprising:

[0008] The beam wavelength, Doppler frequency shift of the first beam, Doppler frequency shift of the second beam, actual tilt angle of the first beam, and actual tilt angle of the second beam of the two-dimensional laser Doppler velocimeter are obtained. A third beam is introduced, and the design tilt angle deviation is considered to obtain the transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system.

[0009] The output velocity of the strapdown inertial navigation system in the navigation coordinate system is obtained, and then transformed to the carrier coordinate system and the two-dimensional laser Doppler velocimeter coordinate system to obtain the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system.

[0010] Based on the transformation matrix and the output velocity of the strapdown inertial navigation system in the coordinate system of the two-dimensional laser Doppler velocimeter, the output velocity of the strapdown inertial navigation system in the beam coordinate system is obtained.

[0011] Error parameters of a two-dimensional laser Doppler velocimeter are obtained, and an error model of a strapdown inertial navigation system is constructed. Based on the error model of the strapdown inertial navigation system, a Kalman filter is constructed. The difference between the output velocity of the strapdown inertial navigation system in the beam coordinate system and the velocity of the two-dimensional laser Doppler velocimeter in the beam direction is taken as the filtered observation. The state vector of the combined navigation system composed of the two-dimensional laser Doppler velocimeter and the strapdown inertial navigation system is estimated, and land combined navigation is performed based on the estimation results.

[0012] In one embodiment, the beam wavelength, Doppler frequency shift of the first beam, Doppler frequency shift of the second beam, actual tilt angle of the first beam, and actual tilt angle of the second beam of the two-dimensional laser Doppler velocimeter are obtained. A third beam is introduced, and the design tilt angle deviation is considered. The transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system includes:

[0013] By acquiring the beam wavelength, Doppler frequency shift of the first beam, and Doppler frequency shift of the second beam from a two-dimensional laser Doppler velocimeter, the velocities in the first beam direction and the second beam direction can be obtained:

[0014]

[0015]

[0016] In the formula, υ1 is the velocity along the direction of the first beam, υ2 is the velocity along the direction of the second beam, and λ is the beam wavelength of the two-dimensional laser Doppler velocimeter. The Doppler frequency shift measured for the first beam and The Doppler frequency shift measured for the second beam;

[0017] Obtain the actual tilt angles of the first and second beams, as well as the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system. Based on these actual tilt angles, the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system, the velocity along the first beam direction, and the velocity along the second beam direction, obtain the relationship between the velocimeter's velocity along the first beam direction, the velocity along the second beam direction, and the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system.

[0018]

[0019] υ1=υ y cosθ1+υ z sinθ1

[0020] υ2=υ y cosθ2+υ z sinθ2

[0021] υ1=K1υ y +K2υ z

[0022] υ2=K3υ y +K4υ z

[0023]

[0024] In the formula, υ represents the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system. y υ represents the actual forward velocity of the two-dimensional laser Doppler velocimeter. z θ1 is the actual celestial velocity of the two-dimensional laser Doppler velocimeter, θ2 is the actual tilt angle of the first beam of the two-dimensional laser Doppler velocimeter, K1, K2, K3 and K4 are scaling factors;

[0025] Introducing a third beam as a lateral constraint, we obtain the first relationship between the velocities in the first beam direction, the second beam direction, the third beam direction, and the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system:

[0026]

[0027] Considering design deviations, the transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system is obtained.

[0028] In one embodiment, considering design deviations, the transformation matrix between the two-dimensional laser Doppler velocimeter coordinate system and the beam coordinate system includes:

[0029] Considering design deviations, a second relationship is obtained between the velocities in the first beam direction, the second beam direction, the third beam direction, and the output velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system:

[0030]

[0031] Based on the second relation, the transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system is obtained:

[0032]

[0033] In the formula, C T This is the transformation matrix.

[0034] In one embodiment, the output velocity of the strapdown inertial navigation system in the navigation coordinate system is obtained, and then transformed successively to the carrier coordinate system and the two-dimensional laser Doppler velocimeter coordinate system. The output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system includes:

[0035] The output velocity of the strapdown inertial navigation system in the navigation coordinate system is:

[0036]

[0037] In the formula, n represents the navigation coordinate system. This represents the output velocity of the strapdown inertial navigation system in the navigation coordinate system. This represents the actual velocity of the strapdown inertial navigation system in the navigation coordinate system. For the speed error of the strapdown inertial navigation system;

[0038] Projecting the output velocity of the strapdown inertial navigation system in the navigation coordinate system onto the vehicle coordinate system yields the output velocity of the strapdown inertial navigation system in the vehicle coordinate system:

[0039]

[0040] In the formula, b represents the carrier coordinate system. This represents the output velocity of the strapdown inertial navigation system in the vehicle's coordinate system. Let be the attitude transformation matrix including errors from the n-system to the b-system. Let I be the attitude transformation matrix from the n-system to the b-system, and I3 be the third-order identity matrix. This represents the attitude error of the inertial navigation system.

[0041] The output velocity of the strapdown inertial navigation system in the vehicle coordinate system is transformed to the coordinate system of the two-dimensional laser Doppler velocimeter, resulting in the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system:

[0042]

[0043] φ m =[φ mx φ my φ mz ] T

[0044] In the formula, The output velocity of the strapdown inertial navigation system in the coordinate system of a two-dimensional laser Doppler velocimeter. Let be the attitude transformation matrix including errors from the b-system to the m-system. Let φ be the attitude transformation matrix from the b-system to the m-system. m φ represents the installation angular error between the coordinate system of the two-dimensional laser Doppler velocimeter and the coordinate system of the carrier. mx For pitch installation difference angle error, φ my For the roll installation angle error, φ mz This refers to the heading installation angle error.

[0045] In one embodiment, the output velocity of the strapdown inertial navigation system in the beam coordinate system is obtained based on the transformation matrix and the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system, including:

[0046] Based on the transformation matrix and the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system, the output velocity of the strapdown inertial navigation system in the beam coordinate system is obtained:

[0047]

[0048]

[0049] δK=[δK1δK2δK3δK4] T

[0050]

[0051]

[0052]

[0053]

[0054] In the formula, The output velocity of the strapdown inertial navigation system in the beam coordinate system. The output velocity of the strapdown inertial navigation system in the direction of the first beam. The output velocity of the strapdown inertial navigation system in the second beam direction. The output velocity of the strapdown inertial navigation system in the direction of the third beam. This represents the actual velocity of the strapdown inertial navigation system in the vehicle's coordinate system. The forward velocity of the strapdown inertial navigation system in the coordinate system of a two-dimensional laser Doppler velocimeter is given. The axial velocity of the strapdown inertial navigation system in the coordinate system of a two-dimensional laser Doppler velocimeter is given.

[0055] In one embodiment, obtaining the error parameters of a two-dimensional laser Doppler velocimeter and constructing an error model for a strapdown inertial navigation system includes:

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063] in:

[0064] υ n =[υ E υ N υ U ] T

[0065] δυ n =[δυ E δυ N δυ U ] T

[0066]

[0067]

[0068]

[0069] In the formula, f nυ represents the projection of the specific force obtained from the accelerometer output into the navigation coordinate system. n For the speed information of the strapdown inertial navigation system, υ E υ N υ U δυ represents the eastward velocity, northward velocity, and upward velocity, respectively. n R represents the velocity error of the strapdown inertial navigation system, where L, λ, and h represent Earth's latitude, longitude, and altitude, respectively. M and R N ω represents the radii of curvature of the Earth's meridian and geoid at the location of the carrier, respectively. ie It represents the angular velocity of Earth's rotation.

[0070] In one embodiment, based on the error model of the strapdown inertial navigation system, a Kalman filter is constructed, and the difference between the output velocity of the strapdown inertial navigation system in the beam coordinate system and the velocity of the two-dimensional laser Doppler velocimeter in the beam direction is taken as the filtered observation. The estimation of the state vector of the combined navigation system consisting of the two-dimensional laser Doppler velocimeter and the strapdown inertial navigation system includes:

[0071] The three installation error angle errors, four scaling factor errors, inertial navigation attitude error, velocity error, position error, gyroscope measurement error, and accelerometer measurement error of the two-dimensional laser Doppler velocimeter are collectively used to form the state vector of the integrated navigation system:

[0072]

[0073] In the formula, X(t) is the state vector of the integrated navigation system. For inertial navigation attitude error, δυ n δP represents the velocity error, and δP represents the position error. For gyroscope measurement error, For accelerometer measurement error, φ mx φ my φ mz δK1, δK2, δK3, and δK4 are the three installation angle errors of the two-dimensional laser Doppler velocimeter, and δK4 are the four scaling factor errors.

[0074] Let the difference between the output velocity of the strapdown inertial navigation system in the beam coordinate system and the velocity of the two-dimensional laser Doppler velocimeter in the beam direction be the filtered observation, and use this difference to estimate the state vector:

[0075]

[0076] In the formula, z(t) represents the filtered observations, H(t) is the filter measurement matrix, and V(t) is the measurement noise vector. The velocity of the two-dimensional laser Doppler velocimeter is measured in the three beam directions.

[0077] A tightly coupled land-based integrated navigation device, comprising:

[0078] The acquisition module is used to acquire the beam wavelength, Doppler frequency shift of the first beam, Doppler frequency shift of the second beam, actual tilt angle of the first beam and actual tilt angle of the second beam of the two-dimensional laser Doppler velocimeter, introduce the third beam, and consider the design tilt angle deviation to obtain the transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system.

[0079] The conversion module is used to obtain the output velocity of the strapdown inertial navigation system in the navigation coordinate system, and then convert it to the carrier coordinate system and the two-dimensional laser Doppler velocimeter coordinate system to obtain the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system.

[0080] The calculation module is used to obtain the output velocity of the strapdown inertial navigation system in the beam coordinate system based on the transformation matrix and the output velocity of the strapdown inertial navigation system in the coordinate system of the two-dimensional laser Doppler velocimeter.

[0081] The navigation module is used to acquire the error parameters of the two-dimensional laser Doppler velocimeter and construct the error model of the strapdown inertial navigation system. Based on the error model of the strapdown inertial navigation system, a Kalman filter is constructed, and the difference between the output velocity of the strapdown inertial navigation system in the beam coordinate system and the velocity of the two-dimensional laser Doppler velocimeter in the beam direction is taken as the filtered observation. The state vector of the combined navigation system composed of the two-dimensional laser Doppler velocimeter and the strapdown inertial navigation system is estimated, and land combined navigation is performed based on the estimation results.

[0082] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program performing the following steps:

[0083] The beam wavelength, Doppler frequency shift of the first beam, Doppler frequency shift of the second beam, actual tilt angle of the first beam, and actual tilt angle of the second beam of the two-dimensional laser Doppler velocimeter are obtained. A third beam is introduced, and the design tilt angle deviation is considered to obtain the transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system.

[0084] The output velocity of the strapdown inertial navigation system in the navigation coordinate system is obtained, and then transformed to the carrier coordinate system and the two-dimensional laser Doppler velocimeter coordinate system to obtain the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system.

[0085] Based on the transformation matrix and the output velocity of the strapdown inertial navigation system in the coordinate system of the two-dimensional laser Doppler velocimeter, the output velocity of the strapdown inertial navigation system in the beam coordinate system is obtained.

[0086] Error parameters of a two-dimensional laser Doppler velocimeter are obtained, and an error model of a strapdown inertial navigation system is constructed. Based on the error model of the strapdown inertial navigation system, a Kalman filter is constructed. The difference between the output velocity of the strapdown inertial navigation system in the beam coordinate system and the velocity of the two-dimensional laser Doppler velocimeter in the beam direction is taken as the filtered observation. The state vector of the combined navigation system composed of the two-dimensional laser Doppler velocimeter and the strapdown inertial navigation system is estimated, and land combined navigation is performed based on the estimation results.

[0087] A computer-readable storage medium having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0088] The beam wavelength, Doppler frequency shift of the first beam, Doppler frequency shift of the second beam, actual tilt angle of the first beam, and actual tilt angle of the second beam of the two-dimensional laser Doppler velocimeter are obtained. A third beam is introduced, and the design tilt angle deviation is considered to obtain the transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system.

[0089] The output velocity of the strapdown inertial navigation system in the navigation coordinate system is obtained, and then transformed to the carrier coordinate system and the two-dimensional laser Doppler velocimeter coordinate system to obtain the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system.

[0090] Based on the transformation matrix and the output velocity of the strapdown inertial navigation system in the coordinate system of the two-dimensional laser Doppler velocimeter, the output velocity of the strapdown inertial navigation system in the beam coordinate system is obtained.

[0091] Error parameters of a two-dimensional laser Doppler velocimeter are obtained, and an error model of a strapdown inertial navigation system is constructed. Based on the error model of the strapdown inertial navigation system, a Kalman filter is constructed. The difference between the output velocity of the strapdown inertial navigation system in the beam coordinate system and the velocity of the two-dimensional laser Doppler velocimeter in the beam direction is taken as the filtered observation. The state vector of the combined navigation system composed of the two-dimensional laser Doppler velocimeter and the strapdown inertial navigation system is estimated, and land combined navigation is performed based on the estimation results.

[0092] The aforementioned tightly coupled land-based integrated navigation method establishes the relationship between the velocity in the two-dimensional laser Doppler velocimeter's own coordinate system and the velocity in the beam coordinate system. It analyzes the error terms of the two-dimensional laser Doppler velocimeter during integrated navigation (including four scaling factor errors and three installation angle errors). Based on these error terms, it derives the velocity expression of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter's beam coordinate system. The error terms of the two-dimensional laser Doppler velocimeter and the errors of the strapdown inertial navigation system are used as the state vector of the filter. The difference between the velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter's beam coordinate system and the velocity measured by the two beams of the two-dimensional laser Doppler velocimeter is used as the filtering observation. Feedback corrections are then performed on the integrated navigation system based on the filtering results. Currently, the use of laser Doppler velocimeters is limited to using the synthesized velocity from the velocimeter. While convenient, this method requires sufficient normal beam signals to obtain a reliable synthesized velocity. Compared with existing solutions, this application achieves a deeper and tighter coupling between the two-dimensional laser Doppler velocimeter and the inertial navigation system, building upon the foundation of loose coupling. Instead of directly using the two-dimensional velocity from the two-dimensional laser Doppler velocimeter, it directly uses the raw velocities measured by the two beams of the two-dimensional laser Doppler velocimeter. In other words, it directly uses the beam measurements of the two-dimensional laser Doppler velocimeter without converting them into two-dimensional velocities. This allows the integrated navigation system to continue operating normally even when one of the two-dimensional laser Doppler velocimeter beams fails, greatly improving the robustness of the integrated navigation system. Attached Figure Description

[0093] Figure 1 This is an application scenario diagram of a tightly coupled land-based integrated navigation method in one embodiment;

[0094] Figure 2 This is a flowchart illustrating a tightly coupled land-based integrated navigation method in one embodiment;

[0095] Figure 3 This is an example of the installation position and output optical path diagram of a two-dimensional laser Doppler velocimeter in a tightly integrated navigation system.

[0096] Figure 4 This is a structural block diagram of a tightly coupled land-based integrated navigation device in one embodiment;

[0097] Figure 5 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0098] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0099] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0100] Furthermore, the use of terms such as "first," "second," etc., in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. In the description of this application, "multiple sets" means at least two sets, such as two sets, three sets, etc., unless otherwise explicitly specified.

[0101] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0102] Furthermore, the technical solutions of the various embodiments of this application can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this application.

[0103] The tightly coupled land-based integrated navigation method provided in this application can be applied to, for example... Figure 1 In the application environment shown, terminal 102 communicates with server 104 via a network. Terminal 102 may include, but is not limited to, various personal computers, laptops, smartphones, tablets, and portable wearable devices. Server 104 may be a server corresponding to various portal websites or work system backends.

[0104] This application provides a tightly coupled land-based integrated navigation method, such as... Figure 2 As shown, in one embodiment, the method is applied to Figure 1 Taking the terminal in the example, the explanation includes:

[0105] Step 202: Obtain the beam wavelength, Doppler frequency shift of the first beam, Doppler frequency shift of the second beam, actual tilt angle of the first beam, and actual tilt angle of the second beam of the two-dimensional laser Doppler velocimeter. Introduce the third beam and consider the design tilt angle deviation to obtain the transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system.

[0106] Specifically:

[0107] By acquiring the beam wavelength, Doppler frequency shift of the first beam, and Doppler frequency shift of the second beam of the two-dimensional laser Doppler velocimeter, the velocity of the two-dimensional laser Doppler velocimeter in the first beam direction and the velocity in the second beam direction can be obtained:

[0108]

[0109]

[0110] In the formula, υ1 is the velocity along the direction of the first beam, υ2 is the velocity along the direction of the second beam, and λ is the beam wavelength of the two-dimensional laser Doppler velocimeter. The Doppler frequency shift measured for the first beam and The Doppler frequency shift measured for the second beam;

[0111] Obtain the actual tilt angles of the first and second beams, as well as the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system. Based on these actual tilt angles, the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system, the velocity along the first beam direction, and the velocity along the second beam direction, obtain the relationship between the velocimeter's velocity along the first beam direction, the velocity along the second beam direction, and the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system.

[0112] The actual velocity of the two-dimensional laser Doppler velocimeter in the m-frame is,

[0113]

[0114] υ y and υ z The following relationships exist with υ1 and υ2:

[0115] υ1=υ y cosθ1+υ z sinθ1(4)

[0116] υ2=υ y cosθ2+υ z sinθ2(5)

[0117] Equations (4) and (5) can be rewritten in the following form:

[0118] υ1=K1υ y +K2υ z (6)

[0119] υ2=K3υ y +K4υ z (7)

[0120] in,

[0121] K1=cosθ1(8)

[0122] K2=sinθ1(9)

[0123] K3=cosθ2(10)

[0124] K4=sinθ2(11)

[0125] According to equations (6) and (7), the relationship between the beam measurement velocity of the two-dimensional laser Doppler velocimeter (i.e., the velocity in the first beam direction and the velocity in the second beam direction) and the velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system is as follows:

[0126]

[0127] In the formula, υ represents the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system. y υ represents the actual forward velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system. z θ1 is the actual celestial velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system, θ2 is the actual tilt angle of the first beam of the two-dimensional laser Doppler velocimeter, K1, K2, K3 and K4 are scaling factors.

[0128] A third beam (a virtual beam perpendicular to the plane formed by the first and second beams) is introduced as a lateral constraint. The velocity in the direction of the third beam is always 0, i.e., υ3 = 0.

[0129] According to equations (6) and (7), the relationship between the beam measurement velocity of the two-dimensional laser Doppler velocimeter and the velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system, i.e., the m-system, that is, the first relationship between the velocity in the first beam direction, the velocity in the second beam direction, the velocity in the third beam direction, and the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system, is as follows:

[0130]

[0131] In engineering applications, the actual beam tilt angles θ1 and θ2 will deviate from the design values. Therefore, the scaling factor of the two-dimensional laser Doppler velocimeter obtained based on the tilt angle design values ​​will have a certain error.

[0132] Therefore, in practical applications, considering the design tilt angle deviation, equation (13) takes the following form, that is, based on the first relationship, the second relationship between the velocity in the first beam direction, the velocity in the second beam direction, the velocity in the third beam direction, and the output velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system is obtained as follows:

[0133]

[0134] in,

[0135]

[0136]

[0137]

[0138]

[0139] In the formula, and These represent the design tilt angles of the two beams in a two-dimensional laser Doppler velocimeter. δK i This is the scaling factor error. This represents the output velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system.

[0140] Based on the second relation, the transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system is obtained:

[0141]

[0142] In the formula, C T This is the transformation matrix.

[0143] Step 204: Obtain the output velocity of the strapdown inertial navigation system in the navigation coordinate system, and then transform it to the carrier coordinate system and the two-dimensional laser Doppler velocimeter coordinate system to obtain the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system.

[0144] Specifically:

[0145] In practical applications, the carrier coordinate system (b-frame) of the strapdown inertial navigation system deviates from the m-frame of the two-dimensional laser Doppler velocimeter, resulting in an installation angle error. The accuracy of this installation angle error directly affects the navigation accuracy of the integrated navigation system. Therefore, it is necessary to consider the installation angle error of the two-dimensional laser Doppler velocimeter.

[0146] Moreover, in practical applications, it is impossible to precisely calibrate the two-dimensional laser Doppler velocimeter before each navigation session. Furthermore, significant road bumps during navigation can cause slight changes in the calibration parameters of the two-dimensional laser Doppler velocimeter. Therefore, it is necessary to consider the installation angle error of the two-dimensional laser Doppler velocimeter.

[0147] The output velocity of the strapdown inertial navigation system in the navigation coordinate system is:

[0148]

[0149] In the formula, n represents the navigation coordinate system. This represents the output velocity of the strapdown inertial navigation system in the navigation coordinate system. This represents the actual velocity of the strapdown inertial navigation system in the navigation coordinate system. This refers to the velocity error of the strapdown inertial navigation system in the navigation coordinate system.

[0150] Projecting the output velocity of the strapdown inertial navigation system in the navigation coordinate system onto the vehicle coordinate system yields the output velocity of the strapdown inertial navigation system in the vehicle coordinate system:

[0151]

[0152] In the formula, b represents the carrier coordinate system. This represents the output velocity of the strapdown inertial navigation system in the vehicle's coordinate system. Let be the attitude transformation matrix including errors from the n-system to the b-system. Let I be the attitude transformation matrix from the n-system to the b-system, and I3 be the third-order identity matrix. This represents the attitude error of the inertial navigation system.

[0153] The output velocity of the strapdown inertial navigation system in the vehicle coordinate system is transformed to the coordinate system of the two-dimensional laser Doppler velocimeter, resulting in the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system:

[0154]

[0155] φ m =[φ mx φ my φ mz ] T

[0156] In the formula, The output velocity of the strapdown inertial navigation system in the coordinate system of a two-dimensional laser Doppler velocimeter. Let be the attitude transformation matrix including errors from the b-system to the m-system. Let φ be the attitude transformation matrix from the b-system to the m-system. m φ represents the installation angular error between the coordinate system of the two-dimensional laser Doppler velocimeter and the coordinate system of the carrier. mx For pitch installation difference angle error, φ my For the roll installation angle error, φ mz This refers to the heading installation angle error.

[0157] Step 206: Based on the transformation matrix and the output velocity of the strapdown inertial navigation system in the coordinate system of the two-dimensional laser Doppler velocimeter, obtain the output velocity of the strapdown inertial navigation system in the beam coordinate system.

[0158] Specifically:

[0159] Based on the transformation matrix and the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system, i.e. according to equations (19) and (22), the output velocity of the strapdown inertial navigation system in the beam coordinate system is obtained:

[0160]

[0161]

[0162] δK=[δK1δK2δK3δK4] T (25)

[0163]

[0164]

[0165]

[0166]

[0167] In the formula, The output velocity of the strapdown inertial navigation system in the beam coordinate system. The output velocity of the strapdown inertial navigation system in the direction of the first beam. The output velocity of the strapdown inertial navigation system in the second beam direction. The output velocity of the strapdown inertial navigation system in the direction of the third beam. This represents the actual velocity of the strapdown inertial navigation system in the vehicle's coordinate system. The forward velocity of the strapdown inertial navigation system in the coordinate system of a two-dimensional laser Doppler velocimeter is given. δK represents the celestial velocity of the strapdown inertial navigation system in the coordinate system of the two-dimensional laser Doppler velocimeter, and δK represents the scaling factor error of the two-dimensional laser Doppler velocimeter.

[0168] Step 208: Obtain the error parameters of the two-dimensional laser Doppler velocimeter and construct the error model of the strapdown inertial navigation system; based on the error model of the strapdown inertial navigation system, construct a Kalman filter, and let the difference between the output velocity of the strapdown inertial navigation system in the beam coordinate system and the velocity of the two-dimensional laser Doppler velocimeter in the beam direction be the filtered observation, estimate the state vector of the combined navigation system composed of the two-dimensional laser Doppler velocimeter and the strapdown inertial navigation system, and perform land combined navigation based on the estimation results.

[0169] Specifically:

[0170] Obtain the error parameters of the two-dimensional laser Doppler velocimeter, and construct the error model of the strapdown inertial navigation system in a tightly coupled integrated navigation system consisting of the strapdown inertial navigation system and the two-dimensional laser Doppler velocimeter:

[0171]

[0172]

[0173]

[0174]

[0175]

[0176]

[0177]

[0178] in:

[0179]

[0180]

[0181]

[0182] And:

[0183] υn =[υ E υ N υ U ] T

[0184] δυ n =[δυ E δυ N δυ U ] T

[0185] P=[Lλh] T

[0186] δP=[δLδλδh] T

[0187] In the formula, f n υ represents the projection of the specific force obtained from the accelerometer output into the navigation coordinate system n. n υ is the output speed of the strapdown inertial navigation system. E υ N υ U δυ represents the eastward velocity, northward velocity, and upward velocity, respectively. n Let R represent the velocity error of the strapdown inertial navigation system, L, λ, and h represent the Earth's latitude, longitude, and altitude, respectively, P represent the output position of the strapdown inertial navigation system, δP represent the position error of the strapdown inertial navigation system, and R represent the position error of the strapdown inertial navigation system. M and R N ω represents the radii of curvature of the Earth's meridian and geoid at the location of the carrier, respectively. ie It represents the angular velocity of Earth's rotation.

[0188] The three installation angle errors, four scaling factor errors, inertial navigation attitude error, velocity error, position error, gyroscope measurement error, and accelerometer measurement error of the two-dimensional laser Doppler velocimeter are collectively used to construct the state vector of the tightly coupled integrated navigation system. The state vector in the Kalman filter model is 22-dimensional, i.e.:

[0189]

[0190] In the formula, X(t) is the state vector of the integrated navigation system. For inertial navigation attitude error, δυ n δυ represents the inertial navigation velocity error (i.e., δυ in the above formula), and δP represents the inertial navigation position error. For gyroscope measurement error, For accelerometer measurement error, φ mx φ my φ mzThe three installation angle errors of the two-dimensional laser Doppler velocimeter are pitch installation angle error, roll installation angle error and heading installation angle error, respectively, and δK1, δK2, δK3 and δK4 are four scaling factor errors;

[0191] Based on the error model of the strapdown inertial navigation system expressed by equations (26) to (32) and the state variables described by equation (36), state estimation is performed using a Kalman filter, and its state equation can be expressed as:

[0192]

[0193] In the formula, F(t) is the system state transition matrix, G(t) is the system noise matrix, and w(t) is the system noise vector;

[0194] The system state transition matrix F(t) is expressed as:

[0195]

[0196] in,

[0197]

[0198]

[0199]

[0200]

[0201]

[0202]

[0203] The system noise matrix is ​​represented as:

[0204]

[0205] The system noise vector is represented as:

[0206]

[0207] In the formula, ε wi This indicates the noise of the gyroscope. Indicates the noise level of the accelerometer;

[0208] Let the difference between the output velocity of the strapdown inertial navigation system in the beam coordinate system and the velocity of the two-dimensional laser Doppler velocimeter in the beam direction be the filtering observation. That is, let the difference between the velocity of the strapdown inertial navigation system in the first beam direction and the velocity of the two-dimensional laser Doppler velocimeter in the first beam direction be the first difference; the difference between the velocity of the strapdown inertial navigation system in the second beam direction and the velocity of the two-dimensional laser Doppler velocimeter in the second beam direction be the second difference; and the difference between the velocity of the strapdown inertial navigation system in the third beam direction and the velocity of the two-dimensional laser Doppler velocimeter in the third beam direction be the third difference. Using the first, second, and third differences as filtering observations, the state vector is estimated. That is, the measurement equation in Kalman filtering is:

[0209]

[0210] In the formula, z(t) represents the filtered observations, H(t) is the filter measurement matrix, and V(t) is the measurement noise vector. The velocity of the two-dimensional laser Doppler velocimeter is measured in the three beam directions.

[0211] The measurement matrix H(t) of the filter is expressed as:

[0212]

[0213] The inertial navigation system is corrected by feedback based on the state vector obtained from filtering.

[0214] In this step, the attitude error, velocity error, position error, gyroscope measurement error, accelerometer measurement error of the strapdown inertial navigation system, as well as the scaling factor error and installation difference angle error of the two-dimensional laser Doppler velocimeter, are used as the filtering state vector (i.e., the installation difference angle error and scaling factor error of the two-dimensional laser Doppler velocimeter are used together with the errors of the strapdown inertial navigation system as the state vector). The difference between the velocity calculated by the strapdown inertial navigation system in the three beam directions and the measurement value of the two-dimensional laser Doppler velocimeter in the three beams is used as the filtering observation (i.e., the velocity of the strapdown inertial navigation system in the beam coordinate system of the two-dimensional laser Doppler velocimeter and the velocity measured by the two beams of the two-dimensional laser Doppler velocimeter are used as the filtering observation). Finally, Kalman filtering is used to estimate and correct the filtering state variables in real time, and land integrated navigation is performed based on the corrected positioning results.

[0215] In this embodiment, as Figure 3 As shown, IMU represents Inertial Measurement Unit, LDV represents Two-Dimensional Laser Doppler Velocimetry, and X... b Y b Z b The X-axis represents the coordinate system of the carrier in which the inertial measurement unit is located. m Ym Z m This indicates the coordinate system of the two-dimensional laser Doppler velocimeter. It should also be noted that SINS stands for strapdown inertial navigation system.

[0216] When using a strapdown inertial navigation system, it is necessary to properly install the inertial measurement unit (IMU) and the two-dimensional laser Doppler velocimeter (LDV). Specifically, the IMU should be installed in the center of the rear axle of the vehicle, and the LDV should be installed in a suitable position on the side or rear of the vehicle, ensuring that the beam output by the LDV effectively hits the ground and obtains a strong signal to obtain real-time and effective vehicle velocity information. Before using the strapdown inertial navigation system, the IMU needs to be calibrated to obtain the calibration coefficient error, installation error angle, and zero bias of the gyroscope and accelerometer. Before entering the formal navigation process, system initialization also needs to be completed to obtain initial attitude, velocity, and position, including obtaining the initial position and velocity information of the vehicle and completing initial alignment.

[0217] The aforementioned tightly coupled land-based integrated navigation method is a land-based integrated navigation method that tightly couples a strapdown inertial navigation system with a two-dimensional laser Doppler velocimeter. It is implemented through Kalman filtering. Specifically, it establishes the relationship between the velocity in the two-dimensional laser Doppler velocimeter's own coordinate system and the velocity in the beam coordinate system. To increase lateral constraint, a virtual beam perpendicular to the plane formed by beams one and two is introduced as a third beam, and the velocities in all three directions of the beam are always zero. The error terms of the two-dimensional laser Doppler velocimeter during the integrated navigation process (including four scaling factor errors and three installation angle errors) are analyzed, and based on the two-dimensional laser Doppler... The error term of the velocimeter is used to obtain the velocity expression of the strapdown inertial navigation system in the beam coordinate system of the two-dimensional laser Doppler velocimeter. The error terms of the two-dimensional laser Doppler velocimeter (installation error and scaling factor error) and the error of the strapdown inertial navigation system are combined as the state vector of the filter. The difference between the velocity of the strapdown inertial navigation system in the beam coordinate system of the two-dimensional laser Doppler velocimeter and the velocity measured by the three beams of the two-dimensional laser Doppler velocimeter is used as the filtering observation. A filtering model is constructed, and Kalman filtering is used to estimate the filtering state variables in real time. Feedback corrections are made to the integrated navigation system based on the filtering results. Currently, the use of laser Doppler velocimeters is limited to using the synthesized velocity of the velocimeter. While this method is convenient, it requires sufficient normal beam signals to obtain a reliable synthesized velocity. Compared with existing solutions, this application, based on loose coupling, achieves a deeper tight coupling between the two-dimensional laser Doppler velocimeter and the inertial navigation system. Instead of directly using the two-dimensional velocity from the two-dimensional laser Doppler velocimeter, it directly uses the raw velocities measured by the two beams of the two-dimensional laser Doppler velocimeter, rather than the synthesized velocity. In other words, it directly uses the beam measurements of the two-dimensional laser Doppler velocimeter without converting them into two-dimensional velocities. This allows the integrated navigation system to continue to function normally even when one of the two-dimensional laser Doppler velocimeter beams fails, which greatly improves the robustness of the integrated navigation system.

[0218] It should be understood that, although Figure 2 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 2 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0219] This application also provides a tightly coupled land-based integrated navigation device, such as... Figure 4 As shown, in one embodiment, it includes: an acquisition module 402, a transfer module 404, a calculation module 406, and a navigation module 408, wherein:

[0220] The acquisition module 402 is used to acquire the beam wavelength, Doppler frequency shift of the first beam, Doppler frequency shift of the second beam, actual tilt angle of the first beam and actual tilt angle of the second beam of the two-dimensional laser Doppler velocimeter, introduce the third beam, and consider the design tilt angle deviation to obtain the transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system.

[0221] The conversion module 404 is used to obtain the output velocity of the strapdown inertial navigation system in the navigation coordinate system, and then convert it to the carrier coordinate system and the two-dimensional laser Doppler velocimeter coordinate system to obtain the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system.

[0222] The calculation module 406 is used to obtain the output velocity of the strapdown inertial navigation system in the beam coordinate system based on the transformation matrix and the output velocity of the strapdown inertial navigation system in the coordinate system of the two-dimensional laser Doppler velocimeter.

[0223] Navigation module 408 is used to acquire the error parameters of the two-dimensional laser Doppler velocimeter and construct the error model of the strapdown inertial navigation system. Based on the error model of the strapdown inertial navigation system, a Kalman filter is constructed, and the difference between the output velocity of the strapdown inertial navigation system in the beam coordinate system and the velocity of the two-dimensional laser Doppler velocimeter in the beam direction is taken as the filtered observation. The state vector of the combined navigation system composed of the two-dimensional laser Doppler velocimeter and the strapdown inertial navigation system is estimated, and land combined navigation is performed based on the estimation results.

[0224] Specific limitations regarding tightly coupled land-based integrated navigation devices can be found in the limitations of tightly coupled land-based integrated navigation methods described above, and will not be repeated here. Each module in the aforementioned device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in a computer device, or stored in software in the memory of a computer device, so that the processor can call and execute the corresponding operations of each module.

[0225] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 5As shown, the computer device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The network interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a tightly coupled land-based integrated navigation method. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0226] Those skilled in the art will understand that Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0227] In one embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of the method described above.

[0228] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described above.

[0229] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0230] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0231] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A tightly coupled land-based integrated navigation method, characterized in that, include: To obtain the beam wavelength, Doppler frequency shift of the first beam, Doppler frequency shift of the second beam, actual tilt angle of the first beam, and actual tilt angle of the second beam of the two-dimensional laser Doppler velocimeter, a third beam is introduced, and considering the design tilt angle deviation, the transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the coordinate system of the beam is obtained. Introducing the third beam as a lateral constraint, the first relationship between the velocities in the directions of the first beam, the second beam, and the third beam, and the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system is obtained. In the formula, The actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system. , , and It is a scaling factor; The output velocity of the strapdown inertial navigation system in the navigation coordinate system is obtained, and then transformed to the carrier coordinate system and the two-dimensional laser Doppler velocimeter coordinate system to obtain the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system. Based on the transformation matrix and the output velocity of the strapdown inertial navigation system in the coordinate system of the two-dimensional laser Doppler velocimeter, the output velocity of the strapdown inertial navigation system in the beam coordinate system is obtained. The error parameters of the two-dimensional laser Doppler velocimeter are obtained, and the error model of the strapdown inertial navigation system is constructed. Based on the error model of the strapdown inertial navigation system, a Kalman filter is constructed. The difference between the output velocity of the strapdown inertial navigation system in the beam coordinate system and the velocity of the two-dimensional laser Doppler velocimeter in the beam direction is taken as the filtered observation. The state vector of the combined navigation system composed of the two-dimensional laser Doppler velocimeter and the strapdown inertial navigation system is estimated, and land combined navigation is performed based on the estimation results. include: The three installation error angle errors, four scaling factor errors, inertial navigation attitude error, velocity error, position error, gyroscope measurement error, and accelerometer measurement error of the two-dimensional laser Doppler velocimeter are collectively used to form the state vector of the integrated navigation system: In the formula, This is the state vector of the integrated navigation system. For inertial navigation attitude error, Right now For speed error, For positional error, For gyroscope measurement error, To account for accelerometer measurement error, , , These represent the three installation angular errors of the two-dimensional laser Doppler velocimeter. , , , The error consists of four scaling factors; Let the difference between the output velocity of the strapdown inertial navigation system in the beam coordinate system and the velocity of the two-dimensional laser Doppler velocimeter in the beam direction be the filtered observation, and use this difference to estimate the state vector: In the formula, For filtered observations, The measurement matrix of the filter. This is the measurement noise vector. The velocity of the two-dimensional laser Doppler velocimeter is measured in the three beam directions.

2. The method according to claim 1, characterized in that, To obtain the beam wavelength, Doppler frequency shift of the first beam, Doppler frequency shift of the second beam, actual tilt angle of the first beam, and actual tilt angle of the second beam of the two-dimensional laser Doppler velocimeter, a third beam is introduced, and the design tilt angle deviation is considered. The transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system is obtained, including: By acquiring the beam wavelength, Doppler frequency shift of the first beam, and Doppler frequency shift of the second beam from a two-dimensional laser Doppler velocimeter, the velocities in the first beam direction and the second beam direction can be obtained: In the formula, The velocity along the direction of the first beam, The velocity along the direction of the second beam. The wavelength of the laser beam in a two-dimensional laser Doppler velocimeter. The Doppler frequency shift measured for the first beam and The Doppler frequency shift measured for the second beam; Obtain the actual tilt angles of the first and second beams, as well as the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system. Based on these actual tilt angles, the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system, the velocity along the first beam direction, and the velocity along the second beam direction, obtain the relationship between the velocimeter's velocity along the first beam direction, the velocity along the second beam direction, and the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system. In the formula, The actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system. The actual forward velocity of the two-dimensional laser Doppler velocimeter. The actual celestial velocity measured by the two-dimensional laser Doppler velocimeter. The actual tilt angle of the first beam of the two-dimensional laser Doppler velocimeter. The actual tilt angle of the second beam of the two-dimensional laser Doppler velocimeter. , , and It is a scaling factor; Introducing a third beam as a lateral constraint, we obtain the first relationship between the velocities in the first beam direction, the second beam direction, the third beam direction, and the actual velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system: Considering design deviations, the transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system is obtained.

3. The method according to claim 2, characterized in that, Considering design deviations, the transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system includes: Considering design deviations, a second relationship is obtained between the velocities in the first beam direction, the second beam direction, the third beam direction, and the output velocity of the two-dimensional laser Doppler velocimeter in its own coordinate system: Based on the second relation, the transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system is obtained: In the formula, For the transformation matrix, , This represents the scaling factor error.

4. The method according to claim 3, characterized in that, The output velocity of the strapdown inertial navigation system in the navigation coordinate system is obtained, and then transformed to the carrier coordinate system and the two-dimensional laser Doppler velocimeter coordinate system. The output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system includes: The output velocity of the strapdown inertial navigation system in the navigation coordinate system is: In the formula, n Indicates the navigation coordinate system. This represents the output velocity of the strapdown inertial navigation system in the navigation coordinate system. This represents the actual velocity of the strapdown inertial navigation system in the navigation coordinate system. For the speed error of the strapdown inertial navigation system; Projecting the output velocity of the strapdown inertial navigation system in the navigation coordinate system onto the vehicle coordinate system yields the output velocity of the strapdown inertial navigation system in the vehicle coordinate system: In the formula, b Indicates the carrier coordinate system. This represents the output velocity of the strapdown inertial navigation system in the vehicle's coordinate system. for n Tie b The attitude transformation matrix of the system, including the error. for n Tie b The attitude transformation matrix of the system. It is a third-order identity matrix. This represents the attitude error of the inertial navigation system. The output velocity of the strapdown inertial navigation system in the vehicle coordinate system is transformed to the coordinate system of the two-dimensional laser Doppler velocimeter, resulting in the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system: In the formula, The output velocity of the strapdown inertial navigation system in the coordinate system of a two-dimensional laser Doppler velocimeter. for b Tie m The attitude transformation matrix of the system, including the error. for b Tie m The attitude transformation matrix of the system. This refers to the installation angular error between the coordinate system of the two-dimensional laser Doppler velocimeter and the coordinate system of the carrier. To account for pitch installation angle error, To account for the roll installation angle error, This refers to the heading installation angle error.

5. The method according to claim 4, characterized in that, Based on the transformation matrix and the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system, the output velocity of the strapdown inertial navigation system in the beam coordinate system is obtained as follows: Based on the transformation matrix and the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system, the output velocity of the strapdown inertial navigation system in the beam coordinate system is obtained: In the formula, The output velocity of the strapdown inertial navigation system in the beam coordinate system. The output velocity of the strapdown inertial navigation system in the direction of the first beam. The output velocity of the strapdown inertial navigation system in the second beam direction. The output velocity of the strapdown inertial navigation system in the direction of the third beam. This represents the actual velocity of the strapdown inertial navigation system in the vehicle's coordinate system. The forward velocity of the strapdown inertial navigation system in the coordinate system of a two-dimensional laser Doppler velocimeter is given. The celestial velocity of the strapdown inertial navigation system in the coordinate system of a two-dimensional laser Doppler velocimeter is given. and These represent the design tilt angles of the two beams in a two-dimensional laser Doppler velocimeter.

6. The method according to any one of claims 1 to 5, characterized in that, Obtaining the error parameters of a two-dimensional laser Doppler velocimeter and constructing an error model for a strapdown inertial navigation system includes: in: In the formula, This represents the projection of the specific force obtained from the accelerometer output into the navigation coordinate system. For the speed information of the strapdown inertial navigation system, , , These represent the eastward velocity, the northward velocity, and the upward velocity, respectively. This indicates the speed error of the strapdown inertial navigation system. L , , h These represent Earth's latitude, longitude, and altitude, respectively. and These represent the radii of curvature of the Earth's meridian and circumference at the location of the carrier, respectively. It represents the angular velocity of Earth's rotation.

7. A tightly coupled land-based integrated navigation device, characterized in that, The tightly coupled land integrated navigation method according to any one of claims 1 to 6 includes: The acquisition module is used to acquire the beam wavelength, Doppler frequency shift of the first beam, Doppler frequency shift of the second beam, actual tilt angle of the first beam and actual tilt angle of the second beam of the two-dimensional laser Doppler velocimeter, introduce the third beam, and consider the design tilt angle deviation to obtain the transformation matrix between the coordinate system of the two-dimensional laser Doppler velocimeter and the beam coordinate system. The conversion module is used to obtain the output velocity of the strapdown inertial navigation system in the navigation coordinate system, and then convert it to the carrier coordinate system and the two-dimensional laser Doppler velocimeter coordinate system to obtain the output velocity of the strapdown inertial navigation system in the two-dimensional laser Doppler velocimeter coordinate system. The calculation module is used to obtain the output velocity of the strapdown inertial navigation system in the beam coordinate system based on the transformation matrix and the output velocity of the strapdown inertial navigation system in the coordinate system of the two-dimensional laser Doppler velocimeter. The navigation module is used to acquire the error parameters of the two-dimensional laser Doppler velocimeter and construct the error model of the strapdown inertial navigation system. Based on the error model of the strapdown inertial navigation system, a Kalman filter is constructed, and the difference between the output velocity of the strapdown inertial navigation system in the beam coordinate system and the velocity of the two-dimensional laser Doppler velocimeter in the beam direction is taken as the filtered observation. The state vector of the combined navigation system composed of the two-dimensional laser Doppler velocimeter and the strapdown inertial navigation system is estimated, and land combined navigation is performed based on the estimation results.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

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