Inertial navigation / polarization compass / laser velocimeter combined navigation method

Abstract

The invention relates to an inertial navigation / polarization compass / laser velocimeter integrated navigation method, which belongs to the technical field of inertial navigation / integrated navigation, and comprises the following steps: mounting and fixing an inertial navigation system, a polarization compass and a laser velocimeter on a carrier, and acquiring coordinate systems of sensors; establishing a polarization compass error equation and a laser velocimeter error equation by considering a course angle installation error, a pitch angle installation error and a scale error of the laser velocimeter; and deriving an inertial navigation / polarization compass / laser velocimeter combined system state equation based on the error equation, establishing a measurement equation by taking the difference between the speed calculated by inertial navigation and the speed of the laser velocimeter and the product of the polarization vector of the polarization compass and the sun vector as observed quantities, and carrying out estimation and feedback correction on the system state. The invention provides an inertial navigation / polarization compass / laser velocimeter combined navigation method in a satellite navigation denial environment, which realizes full-autonomous and high-precision directional positioning.

Description

Technical Field

[0001] The invention belongs to the field of inertial navigation technology / combined navigation technology, and in particular relates to an inertial navigation / polarization compass / laser velocimeter combined navigation method. Background Art

[0002] There have been some developments in navigation methods in satellite-denied environments. In the existing polarization navigation method, based on the principle of Rayleigh scattering, inertial / polarization-based combined navigation is realized, but this method can only solve the problem of carrier heading orientation; then researchers added optical flow or visual sensors to realize inertial / polarization / optical flow combined navigation or inertial / polarization / vision combined navigation methods. These two combined navigation methods can achieve orientation and positioning, but because the optical flow sensor is easily affected by light and the number of optical flows is sparse, the measurement accuracy is not high. Compared with the optical flow sensor, the visual effect measurement accuracy is slightly higher, but in the Chinese patent application "A UAV pose estimation method based on visual inertial polarization light fusion" (application number: CN202010623718.1), the combination of vision and inertial navigation / polarization compass is only suitable for low-dynamic scenes. In high-dynamic scenes, the visual measurement update frequency is slow, the dynamics is low, and the impact of light is relatively large. The heading error during turning is large, resulting in low stability of the combined system and the error will diverge rapidly over time. The measurement principle of laser velocimeter is to detect the frequency shift of the incident wave and the echo signal according to the Doppler effect of light to calculate the carrier's movement speed. It has the advantages of full autonomy, high precision, wide measurement range and high dynamics, and is widely used in integrated navigation systems and provides position estimation. Therefore, it is urgent to study a combined system of laser velocimeter and inertial navigation / polarization compass to achieve fully autonomous and high-precision navigation and orientation positioning in a satellite-denied environment. Summary of the invention

[0003] In order to solve the problem of fully autonomous and high-precision directional positioning of the combined system in a satellite-denied environment in actual engineering, the present invention provides an inertial navigation / polarization compass / laser velocimeter combined navigation method applied in a satellite-denied environment to achieve fully autonomous and high-precision navigation directional positioning.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] An inertial navigation / polarization compass / laser velocimeter combined navigation method comprises the following steps:

[0006] Step 1: Fix the sensors of the inertial navigation system, polarization compass and laser velocimeter respectively to the top of the carrier just above the geometric center of the laser velocimeter, the center of mass of the carrier and the top of the carrier just above the laser velocimeter, and obtain the carrier coordinate system at the same time. System, polarized compass coordinate system Coordinate system and laser velocimeter coordinate system During installation, ensure that the carrier coordinate system System, polarized compass coordinate system Coordinate system and laser velocimeter coordinate system Corresponding axis, Axis and The three axis coordinate directions point in the same direction;

[0007] Step 2: Power on the INS and obtain the initial attitude after rough alignment and fine alignment. , binding the initial attitude of the inertial navigation system ,speed and location , the heading installation angle of the laser speed meter , Pitch installation angle and scale , initial value of polarization angle of polarization compass and the initial value of the sun vector ;

[0008] Step 3: Power on the inertial navigation system, polarized compass and laser velocimeter combined system, enter the combined navigation mode, and collect the gyro three-axis angular rate information. , Accelerometer three-axis force information , Polarization compass polarization angle , Laser velocimeter speed and time ; Use the collected data to calculate the inertial navigation speed of the carrier in different motion states , the speed of the carrier under the laser velocimeter navigation system , polarization vector of polarization compass and sun vector ;The superscript T indicates the transpose of the matrix;

[0009] Step 4: Use the inertial error equation, polarization compass error equation and laser velocimeter error equation to construct the Kalman filter state equation of the inertial / polarization compass / laser velocimeter combined system, and convert the inertial guidance velocity of the carrier in different motion states calculated in step 3 into The speed of the laser speedometer navigation system with the carrier The difference between the polarization vector and the polarization compass Vector with sun The product of is used as the measurement and input into the measurement equation of the Kalman filter to estimate and correct the system state.

[0010] Beneficial effects:

[0011] In the present invention, the laser velocimeter has the advantages of full autonomy, high precision, wide measurement range and high dynamics, etc. It can accurately measure the carrier speed, and the polarization compass measures the polarization angle to solve the polarization vector. The laser velocimeter is combined with the inertial navigation / polarization compass, and the state equation of the combined system filter is established by combining the inertial navigation error equation, the polarization compass error equation and the laser velocimeter error equation. The difference between the speed solved by the inertial navigation and the speed of the laser velocimeter and the product of the polarization vector and the solar vector are used as observation quantities to establish the measurement equation and estimate and feedback correct the system state. The combined system realizes full autonomy and high-precision directional positioning in the horizontal direction, laying a foundation for engineering application of high-precision directional positioning in a satellite denial environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A flowchart of an inertial navigation / polarization compass / laser velocimeter combined navigation method of the present invention;

[0013] Figure 2 It is a schematic diagram of the installation of the inertial navigation, polarization compass and laser velocimeter of the present invention;

[0014] Figure 3a This is a diagram of the gyro zero drift estimation result of the present invention;

[0015] Figure 3b This is a diagram of the accelerometer zero bias estimation result of the present invention;

[0016] Figure 4a This is a diagram of the heading angle error estimation result of the laser speed meter of the present invention;

[0017] Figure 4b This is a diagram of the scale error estimation result of the laser velocimeter of the present invention;

[0018] Figure 4c This is a diagram of the pitch angle error estimation result of the laser velocimeter of the present invention;

[0019] Figure 5a This is a diagram of the heading angle error estimation result of the combined system of the present invention;

[0020] Figure 5b It is a diagram of the pitch angle error estimation result of the combined system of the present invention;

[0021] Figure 5c This is a roll angle error estimation result diagram of the combined system of the present invention;

[0022] Figure 6a This is a diagram of the eastward velocity error estimation result of the present invention;

[0023] Figure 6b This is a north velocity error estimation result diagram of the present invention;

[0024] Figure 6cThis is a diagram of the celestial velocity longitude error estimation result of the present invention;

[0025] Figure 7a This is a diagram of the longitude error estimation result of the present invention.

[0026] Figure 7b This is a diagram of the latitude error estimation result of the present invention.

[0027] Figure 7c This is a diagram of the height error estimation result of the present invention.

[0028] Among them, the reference numerals are: inertial navigation system 1, polarization compass 2, laser speed meter 3, UPS power supply 4, computer 5. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] It should be noted that in the following text, the tilde above the letter symbol represents the actual measurement value, and the letter symbol without the tilde represents the accurate value.

[0031] like Figure 1 As shown, an inertial navigation / polarization compass / laser velocimeter combined navigation method of the present invention comprises the following steps:

[0032] Step 1: Install the inertial navigation system on the carrier (i.e. Figure 1 The inertial navigation system 1, polarization compass 2 and laser velocimeter 3 are fixed to the top of the geometric center of the laser velocimeter, the center of mass of the carrier and the roof of the car above the laser velocimeter, respectively, and the carrier coordinate system ( system), polarized compass coordinate system ( system) and the laser velocimeter coordinate system ( System), the specific installation method is as follows Figure 2 As shown, the arrow indicates the direction of vehicle travel on the ground. The inertial navigation system 1, polarization compass 2 and laser speed meter 3 are connected to UPS power supply 4 and three serial ports of computer 5 for data collection.

[0033] Step 2: Bind the initial attitude of the inertial navigation system 1 , initial speed and initial position , laser speed meter heading installation angle , laser velocimeter pitch installation angle and laser velocimeter scale , initial value of polarization angle of polarization compass and the initial value of the sun vector (Right now Figure 1 The inertial navigation system is powered on, and the inertial navigation system 1 is coarsely aligned and finely aligned to obtain the accurate initial attitude angle of the inertial navigation system. (Right now Figure 1 Start the inertial navigation system in the process of warming up the inertial navigation system and perform rough and fine alignment);

[0034] Step 3: Power on the combined system and enter the combined navigation mode to collect data from the laser velocimeter, strapdown inertial navigation system, and polarization compass, i.e., collect data from the gyro three-axis ( axis, Axis and Axis) angular rate information , Accelerometer three-axis force information , Polarization compass polarization angle , Laser velocimeter speed and time ; Use the collected data to calculate the inertial navigation speed of the carrier under different motion states , the speed of the carrier under the laser velocimeter navigation system , polarization vector of polarization compass and sun vector ; The strapdown inertial navigation system is the inertial navigation system 1;

[0035] Step 4: Use the inertial error model, polarization compass error model and laser velocimeter error model to construct the state equation of the Kalman filter of the inertial / laser velocimeter / polarization compass combined system, perform inertial / laser velocimeter / polarization compass combined navigation, and convert the inertial navigation speed of the carrier under different motion states calculated in step 3 into The speed of the laser speedometer navigation system with the carrier The difference between the polarization vector and the polarization compass Vector with sun The product of is used as the measurement quantity and is input into the measurement equation of the Kalman filter to estimate and correct the system state, realize error compensation and correction, and finally output the carrier attitude, speed and position.

[0036] Among them, step 1 to step 4 are divided into three stages: step 1 and step 2 are the preparation stage, step 3 is the data acquisition and processing stage, and step 4 is the stage of establishing the state equation and measurement equation of the combined system using Kalman filtering.

[0037] Specifically, the step 3 includes:

[0038] The collected gyro three-axis angular rate information Compare force information with accelerometer Substitute the inertial navigation solution equation to calculate the inertial navigation velocity of the carrier under different motion states ; Known laser wavelength , Doppler frequency shift of the echo signal detected by the laser velocimeter and the angle between the laser beam and the target speed , solve the ideal speed in the laser velocimeter coordinate system , is the scale factor. Considering the attitude misalignment angle of the inertial system , Heading angle installation error of laser velocimeter , Pitch angle installation error of laser velocimeter , Roll angle installation error of laser velocimeter and the scale error of the laser velocimeter , then the speed of the carrier under the laser velocimeter navigation system is It is expressed as:

[0039] (1)

[0040] in, is the rotation matrix from the actual carrier system to the laser velocimeter coordinate system, is the rotation matrix from the ideal carrier system to the laser velocimeter coordinate system, is the actual rotation matrix from the carrier system to the navigation system, is the ideal rotation matrix from the carrier system to the navigation system; for The identity matrix of is the angular installation error matrix of the laser velocimetry, is the platform attitude misalignment angle The antisymmetric matrix of Represents antisymmetric matrix symbol.

[0041] By rearranging the above formula, the error model of the laser velocimeter can be obtained as follows:

[0042] (2)

[0043] in, is the speed measurement error of the laser velocimeter, represents the velocity in the carrier coordinate system, express The antisymmetric matrix of .

[0044] Assume that the polarization azimuth measured by the polarization compass is , then the polarization vector of the polarization compass of the carrier system is for:

[0045] (3)

[0046] Among them, the superscript Represents the transpose of a matrix.

[0047] Given the solar calendar information, extract the solar right ascension for a specific date and time. , Declination And location information, the longitude of the known observation location ,latitude and Greenwich Mean Time , calculate the sidereal time for:

[0048] (4)

[0049] Then the solar altitude angle in the navigation system is , azimuth and sun vector The calculation is as follows:

[0050] (5)

[0051] (6)

[0052] The solar vector calculated using equations (5) and (6) is for:

[0053] (7)

[0054] The solar hour angle , , , They are the eastward solar vector, the northward solar vector, and the celestial solar vector.

[0055] According to the Rayleigh scattering principle, the solar vector and the polarization vector are perpendicular to each other, and the vector product of the two is zero, so:

[0056] (8)

[0057] Specifically, the step 4 includes:

[0058] Step 4.1 Establish the state equation of the combined system:

[0059] Establish an 18-dimensional state matrix including inertial navigation position error, velocity error, platform attitude misalignment angle, gyro constant drift, accelerometer bias, laser velocimeter scale coefficient error, and laser velocimeter installation angle error :

[0060] (9)

[0061] Among them, the location , , and are longitude, latitude and altitude, is the position error, , and are longitude error, latitude error and altitude error respectively; speed , , and They are the speed in the east, the speed in the north and the speed in the sky, and the speed error , , and They are the velocity error in the east direction, the velocity error in the north direction, and the velocity error in the sky direction; the platform attitude misalignment angle , , and They are the misalignment angles in the east, north and celestial directions respectively; the three-axis constant drift under the gyro bearing system , accelerometer load system three-axis bias , , is the heading angle installation error of the laser velocimeter and the pitch angle installation error of the laser velocimeter, is the scale error of the laser velocimeter.

[0062] The state equation of the combined system is:

[0063] (10)

[0064] in, is the state differential matrix.

[0065] Among them, the state transfer matrix , , , They are the relative force in the east, the relative force in the north, and the relative force in the sky;

[0066] Intermediate Matrix ;

[0067] in, , Indicates the radius of curvature of the meridian circle and the radius of curvature of the meridian circle;

[0068] Intermediate Matrix ;

[0069] in, is the Earth's rotation angular rate;

[0070] Intermediate Matrix ;

[0071] Intermediate Matrix ;

[0072] Intermediate parameters ;

[0073] The system noise driving matrix is: ;

[0074] for OK Full list vector;

[0075] The noise matrix is ,in, , , is the random walk of the accelerometer on the three axes, , , It is the random walk of the gyroscope along three axes.

[0076] Step 4.2 Establish the measurement equation of the combined system:

[0077] The inertial navigation speed of the carrier under different motion states Speed ​​under laser velocimeter navigation system The measurement equations of the inertial navigation and laser velocimeter are constructed as follows:

[0078] (11)

[0079] in, It is the quantity measurement of laser velocimeter; , , , They are respectively the true value of velocity calculated by inertial navigation and the true value of velocity under the navigation system of laser velocimeter. , They are respectively the inertial navigation velocity solution error and the velocity error in the laser velocimeter navigation system.

[0080] According to the Rayleigh scattering principle, the polarization vector of the polarization compass Vector with sun The product of is zero, and the measurement equation of the polarization compass can be constructed as:

[0081] (12)

[0082] in, Polarization compass quantity measurement.

[0083] Then the measurement equation of the combined system is:

[0084] (13)

[0085] (14)

[0086] in, For the measurement of the combined system, is the noise, the combined system measurement matrix for:

[0087] ;

[0088] in, Measuring noise for laser velocimeter, is the polarization compass measurement noise, for The antisymmetric matrix of is the rotation matrix The elements in the p-th row and q-th column, p=1,2,3,q=1,2,3.

[0089] Step 4.3 Feedback correction of the combined system:

[0090] Based on the state equation and measurement equation of the combined navigation system established above, the Kalman filter is used to estimate the system state and obtain the gyro three-axis constant drift. , , , Accelerometer three-axis bias , , and platform attitude misalignment angle The accurate value of; the scale error of the laser velocimeter , Laser speed meter heading angle installation error angle and pitch angle installation error angle The accurate value of the carrier's eastward velocity error , velocity error in the north direction The velocity error with the celestial direction and longitude error , Latitude Error and height error .

[0091] After filtering state estimation and correction, the accurate values ​​of the gyro three-axis angular rates are , , The accurate values ​​of the three-axis specific force of the accelerometer are , , , Convert to The exact rotation matrix is , the accurate speed of the laser velocimeter is The exact values ​​of the carrier's eastward, northward, and celestial velocities are , and , , , are the measured speeds of the carrier in the east, north and sky directions respectively; the accurate values ​​of longitude, latitude and altitude are , and , , , The measurements are longitude, latitude, and altitude respectively.

[0092] Among them, the letter symbol with a tilde above it represents the actual measurement value, and the letter symbol without a tilde above it represents the accurate value.

[0093] Example:

[0094] The embodiment of the present invention provides an inertial navigation / polarization compass / laser velocimeter combined navigation method, and the specific steps are as follows:

[0095] Step 1: Figure 1 As shown, the initial position is bound to the inertial navigation system through the host computer interface ,speed , gyro three-axis constant drift Set to , accelerometer three-axis bias Set to , the upper computer interface binds the laser speed meter parameters heading installation angle and pitch angle , scale After the parameters are set, set the initial alignment for the inertial navigation to obtain the accurate initial attitude .

[0096] Step 2: Start the laser speed meter and polarization compass, and drive the car on the asphalt road to collect the gyro three-axis angular rate information. , , And accelerometer three-axis specific force information , , Substitute the inertial navigation solution equation to calculate the velocity of the inertial navigation coordinate system ; Known laser wavelength , Doppler frequency shift of the echo signal detected by the laser velocimeter and the angle between the laser beam and the target speed , solve the velocity in the laser velocimeter coordinate system , get the polarization angle and time Calculate the polarization vector and sun vector .

[0097] Step 3: The inertial navigation speed calculated in step 3 , Laser velocimeter speed , polarization vector and sun vector The parameters are introduced into the state equation (10) and measurement equation (14) of the combined system for filtering calculation and state estimation and error correction.

[0098] According to the above steps, Figure 3a , Figure 3b This is the error estimation result diagram of the three-axis gyroscope and the three-axis accelerometer. Figure 3a It can be seen that the three-axis gyro zero offset estimation result converges to Nearby, which is basically consistent with the preset value. Figure 3b It can be seen that the zero bias estimation result of the three-axis accelerometer converges to It is basically consistent with the preset value.

[0099] Figure 4a , Figure 4b , Figure 4c The figure below shows the estimated results of the heading angle installation error, scale factor error and pitch angle installation error of the laser velocimeter. Figure 4a It can be seen that the estimation result of the heading angle installation error of the laser velocimeter converges to Nearby, from Figure 4b It can be seen that the error estimate of the scale factor converges to Nearby, from Figure 4c It can be seen that the pitch angle installation error estimation result converges to It is basically consistent with the preset result and can realize error estimation and compensation.

[0100] Figure 5a , Figure 5b , Figure 5c The figure below shows the attitude error, velocity error and position error estimation results of the inertial navigation / polarization compass / laser velocimeter integrated navigation system. Figure 5a and Figure 5b It can be seen from the figure that the error estimates of the heading angle and pitch angle are Fluctuation within Figure 5c It can be seen that the estimated value of the roll angle error is The fluctuations are within 3.0, and the errors of the three do not diverge.

[0101] Figure 6a , Figure 6b , Figure 6c The figure in the middle shows the eastward, northward and celestial velocity error estimation results of the inertial navigation / polarization compass / laser velocimeter integrated navigation system. Figure 6a and Figure 6b It can be seen that the eastward velocity error and the northward velocity error are Fluctuates within the range Figure 6c It can be seen that the error in the celestial velocity is relatively large, but there is The trend of convergence near .

[0102] Figure 7a , Figure 7b , Figure 7c The estimated values ​​of latitude error, longitude error and height error can be seen in the figure. Figure 7a , Figure 7b It can be seen that the latitude error and longitude error are In the range, from Figure 7c It can be seen that the height error fluctuates greatly, but tends to converge to 0m, so the combined system can achieve fully autonomous, high-precision directional positioning.

Claims

1. An inertial navigation / polarization compass / laser velocimeter combined navigation method, characterized in that: The steps include: Step 1: Fix the sensors of the inertial navigation system, polarization compass and laser velocimeter respectively to the top of the carrier just above the geometric center of the laser velocimeter, the center of mass of the carrier and the top of the carrier just above the laser velocimeter, and obtain the carrier coordinate system at the same time. System, polarized compass coordinate system Coordinate system and laser velocimeter coordinate system During installation, ensure that the carrier coordinate system System, polarized compass coordinate system Coordinate system and laser velocimeter coordinate system Corresponding axis, Axis and The three axis coordinate directions point in the same direction; Step 2: Power on the INS and obtain the initial attitude after rough alignment and fine alignment. , binding the initial attitude of the inertial navigation system ,speed and location , the heading installation angle of the laser speed meter , Pitch installation angle and scale , initial value of polarization angle of polarization compass and the initial value of the sun vector ; Step 3: Power on the inertial navigation system, polarized compass and laser velocimeter combined system, enter the combined navigation mode, and collect the gyro three-axis angular rate information. , Accelerometer three-axis force information , Polarization compass polarization angle , Laser velocimeter speed and time ; Using the collected data, calculate the inertial navigation speed of the carrier in different motion states , the speed of the carrier under the laser velocimeter navigation system , polarization vector of polarization compass and sun vector ;The superscript T indicates the transpose of the matrix; Step 4: Use the inertial error equation, polarization compass error equation and laser velocimeter error equation to construct the Kalman filter state equation of the inertial / polarization compass / laser velocimeter combined system, and convert the inertial guidance velocity of the carrier in different motion states calculated in step 3 into The speed of the laser speedometer navigation system with the carrier The difference between the polarization vector and the polarization compass Vector with sun The product of is used as the measurement and input into the measurement equation of the Kalman filter to estimate and correct the system state.

2. The inertial navigation / polarization compass / laser velocimeter combined navigation method according to claim 1, characterized in that: The step 3 comprises: The collected gyro three-axis angular rate information , , And accelerometer three-axis specific force information , , Substitute the inertial navigation solution equation to calculate the inertial navigation velocity of the carrier under different motion states ; Known laser wavelength , Doppler frequency shift of the echo signal detected by the laser velocimeter and the angle between the laser beam and the target speed , solve the ideal speed in the laser velocimeter coordinate system , is the scale; considering the platform attitude misalignment angle of the inertial group , Heading angle installation error of laser velocimeter , Pitch angle installation error of laser velocimeter , Roll angle installation error of laser velocimeter and the scale error of the laser velocimeter , then the speed of the carrier under the laser velocimeter navigation system is It is expressed as: (1) in, is the rotation matrix from the laser velocimeter coordinate system to the carrier system, is the rotation matrix from the actual laser velocimeter coordinate system to the carrier system, is the actual rotation matrix from the carrier system to the navigation system, is the ideal rotation matrix from the carrier system to the navigation system, for The identity matrix of is the installation angle error matrix of the laser velocimeter, is the platform attitude misalignment angle The antisymmetric matrix of Represents antisymmetric matrix symbol.

3. The inertial navigation / polarization compass / laser velocimeter combined navigation method according to claim 2, characterized in that: After rearranging equation (1), the error model of the laser velocimeter is obtained as follows: (2) in, is the speed measurement error of the laser velocimeter, represents the velocity in the carrier coordinate system, express The antisymmetric matrix of ; Assume that the polarization azimuth measured by the polarization compass is , then the polarization vector of the carrier system is: (3)。 4. The inertial navigation / polarization compass / laser velocimeter combined navigation method according to claim 3, characterized in that: Extract the solar right ascension for a specific date and time from the solar almanac information , Declination And location information, the longitude of the known observation location ,latitude and Greenwich Mean Time , calculate the sidereal time as , and then according to the declination ,latitude and solar hour angle Find the solar altitude angle and azimuth , then the sun vector for: (7) in, , , They are the eastward solar vector, the northward solar vector, and the celestial solar vector; According to the Rayleigh scattering principle, the solar vector and the polarization vector are perpendicular to each other. With polarization vector The vector product of is zero, then: (8) in, Vector for the sun The transpose of .

5. The inertial navigation / polarization compass / laser velocimeter combined navigation method according to claim 4, characterized in that: The step 4 comprises: Step 4.1 Establish the state equation of the inertial / polarization compass / laser velocimeter combined system; Step 4.2 Establish the measurement equation of the inertial / polarization compass / laser velocimeter combined system; Step 4.3 performs feedback correction of the inertial / polarization compass / laser velocimeter combined system.

6. The inertial navigation / polarization compass / laser velocimeter combined navigation method according to claim 5, characterized in that: The step 4.1 comprises: Establish an 18-dimensional state matrix including inertial navigation position error, velocity error, platform attitude misalignment angle, gyro constant drift, accelerometer bias, laser velocimeter scale error, and laser velocimeter installation angle error for: (9) Among them, the location , , and are longitude, latitude and altitude, is the position error, , and are longitude error, latitude error and altitude error respectively; speed , , and They are the speed in the east, the speed in the north and the speed in the sky, and the speed error , , and They are the velocity error in the east direction, the velocity error in the north direction, and the velocity error in the sky direction; the platform attitude misalignment angle , , and They are the misalignment angles in the east, north and celestial directions respectively; the three-axis constant drift under the gyro system , accelerometer load system three-axis bias , , is the heading angle installation error of the laser velocimeter and the pitch angle installation error of the laser velocimeter, is the scale error of the laser velocimeter; The state equation of the inertial / polarization compass / laser velocimeter combined system is: (10) in, is the state differential matrix, is the state transfer matrix, is the state matrix, is the state noise driving array, is the noise matrix.

7. The inertial navigation / polarization compass / laser velocimeter combined navigation method according to claim 6, characterized in that: The step 4.2 comprises: The inertial velocity of the carrier in different motion states The speed of the laser speedometer navigation system with the carrier By making a difference, the measurement equations of the inertial navigation and laser velocimeter are constructed as follows: (11) in, Laser velocimeter measurement, , , , They are the accurate values ​​of inertial navigation velocity solution and laser velocimeter velocity respectively. , Calculate speed error for inertial navigation and measure speed error for laser velocimeter; According to the Rayleigh scattering principle, the polarization vector calculated by the polarization compass Vector with sun The product of is zero, and the measurement equation for constructing the polarization compass is: (12) in, Polarization compass measurement; The measurement equation of the inertial / polarization compass / laser velocimeter combined system is: (14) in, For combined system quantity measurement, is the noise, the measurement matrix for: ； in, Measuring noise for laser velocimeter, is the polarization compass measurement noise, for The antisymmetric matrix of is the rotation matrix The elements in the pth row and qth column of , p=1,2,3,q=1,2,3; is the total number of rows and columns i Vector; i=1,3, j=3,6,9.

8. The inertial navigation / polarization compass / laser velocimeter combined navigation method according to claim 7, characterized in that: The step 4.3 comprises: Based on the state equation and measurement equation of the inertial / polarization compass / laser velocimeter combined system established above, the Kalman filter is used to estimate the system state and obtain the gyro three-axis constant drift , , , Accelerometer three-axis bias , , and platform attitude misalignment angle The accurate value of; the scale error of the laser velocimeter , Heading angle installation error of laser velocimeter and the pitch angle installation error of the laser velocimeter The accurate value of the carrier eastward velocity error , Carrier north velocity error and the carrier celestial velocity error and longitude error , Latitude Error and height error ; After filtering state estimation and correction, the accurate values ​​of the gyro three-axis angular rates are , , The accurate values ​​of the three-axis specific force of the accelerometer are , , , carrier coordinate system Switch to navigation system The exact rotation matrix is , the accurate speed of the laser velocimeter is The exact values ​​of the carrier’s eastward, northward, and celestial velocities are , and ; The exact values ​​of longitude, latitude and altitude are , and ; Among them, the letter symbol with a tilde above it represents the actual measurement value, and the letter symbol without a tilde above it represents the accurate value.

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