A method for compensating polarization light orientation error

Abstract

The present invention discloses a method for compensating polarization light orientation errors, comprising: obtaining an atmospheric polarization image and constructing a polarization vector non-orthogonal error angle model; solving the polarization vector non-orthogonal error angle model to obtain the non-orthogonal error angle of each observation point in the atmospheric polarization image; calculating the E vector of each observation point based on the non-orthogonal error angle, and obtaining the heading angle of the carrier. The present invention is applied to the field of polarization light navigation. By quantitatively introducing non-orthogonal error into the construction process of the polarization vector non-orthogonal error angle model, the polarization vector non-orthogonal error is compensated based on prior information based on the characteristic that the non-orthogonal error angle changes slowly over a short period of time, thereby estimating the non-orthogonal error angle of the observation point in the atmospheric polarization image. This method can better compensate for the impact of the non-orthogonal error angle on the orientation result, and is effectively suitable for orientation in cloudy weather with large non-orthogonal error angles.

Description

Technical Field

[0001] The invention relates to the technical field of polarized light navigation, in particular to a method for compensating polarized light orientation errors. Background Art

[0002] Accurate positioning information is the basis for autonomous navigation of long-endurance unmanned platforms. However, in the case of satellite obstruction or complex electromagnetic interference environments, existing inertial navigation systems have accumulated errors and geomagnetic navigation is susceptible to interference, which cannot meet the requirements of high-precision navigation of unmanned platforms.

[0003] During its propagation, sunlight is absorbed and scattered by atmospheric particles, generating polarized light. This large amount of polarized light converges in the sky, forming an atmospheric polarization pattern with a specific distribution pattern. The atmospheric polarization pattern contains directional information. Based on the geometric property of the Rayleigh scattering model, where the E vector of polarized light is perpendicular to the scattering surface, the carrier azimuth can be estimated by measuring atmospheric polarization information. This is the conventional polarization vector orthogonality-based orientation method. While polarization vector orthogonality-based orientation methods can effectively improve orientation accuracy under obstructed conditions on clear days, with few clouds, and in overcast weather, they are less effective on overcast days. This is because polarization degrees are not clearly distinguished on overcast days. Even if a few Rayleigh points exist, they are difficult to identify. The E vectors of non-Rayleigh points are no longer perpendicular to the scattering surface, but instead have an angle with the E vector of the Rayleigh points, known as the polarization vector non-orthogonality error angle. Furthermore, the non-orthogonality error angle of non-Rayleigh points is large on overcast days, and continuing to use polarization vector orthogonality-based orientation methods will introduce significant orientation errors. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for compensating polarized light orientation errors, which compensates for non-orthogonal error angles in the process of calculating the heading angle information of the carrier, and is effectively suitable for orientation in cloudy weather with large non-orthogonal error angles.

[0005] To achieve the above object, the present invention provides a method for compensating for polarization light orientation error, comprising the following steps:

[0006] Step 1: Acquire an atmospheric polarization image and construct a polarization vector non-orthogonal error angle model;

[0007] Step 2, solving the polarization vector non-orthogonal error angle model to obtain the non-orthogonal error angle of each observation point in the atmospheric polarization image;

[0008] Step 3: Calculate the E vector of each observation point based on the non-orthogonal error angle, obtain the sun direction vector according to the E vector of each observation point, and obtain the heading angle of the carrier.

[0009] In one embodiment, in step 1, the process of constructing the polarization vector non-orthogonality error angle model is:

[0010] Decompose the E vector e of the observation point into the coordinate system composed of the sun direction vector s axis, the observation direction vector v axis and the orthogonal axis composed of v×s:

[0011] e=r1·s+r2·v+r3·v×s

[0012] Where r1 = sinη / / sinτ, r2 = -sinη / / tanτ, r3 = -cosη / / sinτ, respectively, are the modulus lengths of the E vector e of the observation point on the three axes, η is the non-orthogonality error angle of the observation point, and τ is the scattering angle;

[0013] Projecting the E vector e of the observation point into the optical compass coordinate system, we have:

[0014] e c =r1·s c +r2·v c +r3·v c ×s c

[0015] Among them, e c is the projection of the E vector e of the observation point on the optical compass coordinate system, s c is the projection of the sun direction vector on the optical compass coordinate system, v c is the projection of the observation direction vector on the optical compass coordinate system;

[0016] Let f(η) = r1·s c +r2·v c +r3·v c ×s c -e c As the objective function, the polarization vector non-orthogonal error angle model is

[0017] In one embodiment, the projection of the E vector e of the observation point on the optical compass coordinate system is specifically:

[0018]

[0019] is the transformation matrix from the observation point coordinate system to the optical compass coordinate system, expressed as:

[0020]

[0021] Among them, α v is the azimuth of the observation point in the optical compass coordinate system, γ v is the zenith angle of the observation point in the optical compass coordinate system, α v , γ v That is the observation information of the observation point;

[0022] e v is the projection of the E vector e of the observation point on the observation point coordinate system, expressed as:

[0023]

[0024] Where φ is the polarization angle of the observation point.

[0025] In one embodiment, the projection of the sun direction vector on the optical compass coordinate system is specifically:

[0026]

[0027] is the transformation matrix from the carrier coordinate system to the optical compass coordinate system, expressed as:

[0028]

[0029] is the transformation matrix from the navigation coordinate system to the optical compass coordinate system, expressed as:

[0030]

[0031] Among them, r0, θ0, and Ψ0 are respectively provided by other sensors to provide the carrier roll angle, pitch angle, and heading angle;

[0032] s n is the sun direction vector in the navigation coordinate system, expressed as:

[0033]

[0034] Where T is the transpose of the matrix, is the azimuth of the sun direction vector in the navigation coordinate system, is the altitude angle of the sun direction vector in the navigation coordinate system. When the time and geographical location are known, It can be obtained through the solar ephemeris.

[0035] In one embodiment, the projection of the observation direction vector on the optical compass coordinate system is specifically:

[0036] v c =[siny v ·cosα v siny v ·sinα v -cosγ v ] T

[0037] Where T is the transpose of the matrix.

[0038] In one embodiment, in step 2, the polarization vector non-orthogonality error angle model is solved based on the interior point method.

[0039] In one embodiment, step 3 is specifically:

[0040] Decompose the E vector e of the observation point into the coordinate system composed of the sun direction vector s axis, the observation direction vector v axis and the orthogonal axis composed of v×s:

[0041] e=r1·s+r2·v+r3·v×s

[0042] Where r1 = sinη / / sinτ, r2 = -sinη / / tanτ, r3 = -cosη / / sinτ, respectively, are the modulus lengths of the E vector e of the observation point on the three axes, η is the non-orthogonality error angle of the observation point, and τ is the scattering angle;

[0043] Projecting the E vector e of the observation point into the optical compass coordinate system, we have:

[0044] e c =r1·s c +r2·v c +r3·v c ×s c

[0045] Further written as:

[0046] e c -r2·v c =r1·s c +r3·[v c ×]s c

[0047] Among them, e c is the projection of the E vector e of the observation point on the optical compass coordinate system, s c is the projection of the sun direction vector on the optical compass coordinate system, v c is the projection of the observation direction vector on the optical compass coordinate system, [v c ×] is v c The antisymmetric matrix of ;

[0048] Because there are:

[0049]

[0050] in, is the transformation matrix from the carrier coordinate system to the optical compass coordinate system, is the transformation matrix from the navigation coordinate system to the optical compass coordinate system, s n is the sun direction vector in the navigation coordinate system;

[0051] Then s c for:

[0052]

[0053]

[0054] in, x c are intermediate parameters, r, θ, and Ψ are the actual carrier roll angle, pitch angle, and heading angle, respectively. is the azimuth of the sun direction vector in the navigation coordinate system, is the altitude angle of the sun direction vector in the navigation coordinate system;

[0055] Further we get:

[0056]

[0057] Among them, E3 is the identity matrix;

[0058] Simplifying to get:

[0059]

[0060] P=(r1·E3+r3·[v c ×])

[0061] Among them, P is the intermediate parameter;

[0062] So we have:

[0063]

[0064] The actual heading angle of the carrier is:

[0065]

[0066] or

[0067]

[0068] Among them, x c (1), x c (2) Divided into vector x c The first and second elements in α s is the solar azimuth angle, and π is the ambiguity of the polarized light orientation.

[0069] Compared with the prior art, the present invention has the following beneficial technical effects:

[0070] The present invention constructs a polarization vector non-orthogonal error angle model and quantitatively introduces the polarization vector non-orthogonal error caused by multiple scattering in cloudy weather into the model construction process. According to the characteristic that the non-orthogonal error angle changes slowly in a short period of time, the polarization vector non-orthogonal error is compensated based on prior information, thereby estimating the non-orthogonal error angle of the observation point in the atmospheric polarization image. This can better compensate for the impact of the non-orthogonal error angle on the orientation result and is effectively suitable for orientation in cloudy weather with a large non-orthogonal error angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0072] Figure 1 Flowchart of a method for compensating for polarized light orientation errors according to an embodiment of the present invention;

[0073] Figure 2 Schematic diagram of the scattering process of sunlight in the sky according to an embodiment of the present invention;

[0074] Figure 3 Schematic diagram of the non-orthogonal error angle of the polarization vector in an embodiment of the present invention;

[0075] Figure 4 Schematic diagram of the first orthogonal relationship of vibration vectors in an embodiment of the present invention;

[0076] Figure 5 Schematic diagram of the second orthogonal relationship of vibration vectors in an embodiment of the present invention.

[0077] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0078] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0079] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0080] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0081] This embodiment discloses a method for compensating for polarization light orientation errors, which primarily estimates the non-orthogonal error angle of an observation point through a polarization vector non-orthogonal error angle model, and then compensates for the estimated non-orthogonal error angle during the orientation process, thereby achieving carrier positioning. By quantitatively introducing the polarization vector non-orthogonal error caused by multiple scattering in cloudy weather into the model construction process, and based on the characteristic that the non-orthogonal error angle changes slowly over a short period of time, the polarization vector non-orthogonal error is compensated based on prior information, thereby estimating the non-orthogonal error angle of the observation point in the atmospheric polarization image. This method can better compensate for the impact of the non-orthogonal error angle on the orientation result, and is effectively suitable for orientation in cloudy weather with large non-orthogonal error angles.

[0082] refer to Figure 1 In this embodiment, the polarization light orientation error compensation method specifically includes the following steps:

[0083] Step 1: Acquire an atmospheric polarization image and construct a polarization vector non-orthogonal error angle model;

[0084] Step 2, solving the polarization vector non-orthogonal error angle model to obtain the non-orthogonal error angle of each observation point in the atmospheric polarization image;

[0085] Step 3: Calculate the E vector of each observation point based on the non-orthogonal error angle, and obtain the sun direction vector according to the E vector of each observation point, and obtain the heading angle of the carrier.

[0086] refer to Figure 2 Schematic diagram of the scattering process of sunlight in the sky, where O c represents the observer on the ground, V represents the observation point in the sky, S represents the sun, Z represents the zenith, N represents the geographic north, τ represents the scattering angle, γ s , α s Represent the solar zenith angle and azimuth respectively, φ represents the polarization angle of the observation point, α v represents the azimuth of the observation point, γ v , α vRepresents the zenith angle and azimuth angle of the observation point V in the polarized compass coordinate system.

[0087] In this embodiment, the right-front-up coordinate system is defined as the polarized light compass coordinate system (hereinafter referred to as the "C system"), X c Axis and Y c The axes point to the horizontal and vertical axes of the polarized light compass, respectively. c The axis is the optical axis direction of the polarized light compass. After leveling, the Z c The axis points to the zenith. Define the North-East-Earth coordinate system as the navigation coordinate system (hereinafter referred to as "n system"), and use O n -X n Y n Z n Indicates that O n With O c coincide, Figure 2 For the sake of simplicity, Y is omitted. n Axis and Z n Axis, X n The axis direction is geographic north. Figure 2 In the figure, N is used to represent the front-right-bottom coordinate system. The front-right-bottom coordinate system is defined as the carrier coordinate system (hereinafter referred to as "b system"), and O is used to represent the b -X b Y b Z b To express, where O b With O c coincide, Figure 2 For the sake of simplicity, Y is omitted. b Axis and Z b Axis, the heading angle Ψ of the carrier is X b The angle between the axis and N. Define O v -X v Y v Z v is the observation point coordinate system (hereinafter referred to as “v system”), Z v The axis points to the direction of the observation point, X v The axis is located in the observation plane ΔO v In VV′, Y v The axis is known from the right-hand rule. Figure 2 For the sake of simplicity, Y is omitted. v Axis. e is the unit vector of the vibration direction of the polarized light E vector at the observation point V, v is the unit vector of the observation direction, and s is the unit vector in the direction of the sun.

[0088] refer to Figure 3 is a schematic diagram of the non-orthogonal error angle of the polarization vector, where the coordinate system is set and Figure 2 In the figure, the polarized light E vector e′ at the Rayleigh point is perpendicular to the scattering plane ΔSO c Ov , the polarized light E vector e at the non-Rayleigh point is not perpendicular to the scattering plane ΔSO c O v Since light is a transverse wave, there is always a polarization vector non-orthogonality error angle between e and e', which is denoted as η in this embodiment.

[0089] refer to Figure 4 、 Figure 5 Regardless of whether the polarization vectors are orthogonal, e can be represented by the incident light direction vector v, the sun direction vector s, and the vector v×s. Therefore, the specific construction process of the polarization vector non-orthogonality error angle model in this embodiment is as follows:

[0090] Step 101: Decompose the E vector e of the observation point into a coordinate system consisting of the sun direction vector s axis, the observation direction vector v axis, and the orthogonal axes v×s, as follows:

[0091] e=r1·s+r2·v+r3·v×s (1)

[0092] Among them, r1 = sinη / / sinτ, r2 = -sinη / / tanτ, r3 = -cosη / / sinτ are the modulus lengths of the E vector e of the observation point on the three axes respectively;

[0093] The calculation process of the scattering angle τ is:

[0094]

[0095] Among them, s c is the projection of the sun direction vector on the optical compass coordinate system, v c is the projection of the observation direction vector on the optical compass coordinate system, and T is the transpose of the matrix;

[0096] Ideally, the non-orthogonal error angle η of the Rayleigh point is 0. In this case, Equation (1) degenerates into the polarization vector orthogonal model, i.e., e = r3·v×s;

[0097] Step 102, project the E vector e of the observation point into the optical compass coordinate system, then:

[0098] e c =r1·s c +r2·v c +r3·v c ×s c (3)

[0099] Among them, e c is the projection of the E vector e of the observation point on the optical compass coordinate system;

[0100] Step 103, let f(η)=r1·s c +r2·v c +r3·v c ×s c -e c is the objective function. Theoretically, f(η)=0. However, due to the existence of the polarization vector non-orthogonality error angle, f(η)≠0. Therefore, the final polarization vector non-orthogonality error angle model is:

[0101]

[0102] In this embodiment, since the non-orthogonal error angle changes slowly in a short period of time, in the process of constructing the polarization vector non-orthogonal error angle model, the projection s of the sun direction vector on the optical compass coordinate system can be calculated using prior information. c , the projection v of the observation direction vector on the optical compass coordinate system c And the projection e of the E vector e of the observation point on the optical compass coordinate system c .

[0103] In this embodiment, the specific calculation process of the projection of the E vector e of the observation point on the optical compass coordinate system is:

[0104]

[0105] is the conversion matrix from v system to c system, expressed as:

[0106]

[0107] Zenith angle γ of the observation point in system C v and azimuth angle α v Specifically:

[0108]

[0109] Among them, (x v ,y v ) is the coordinate of the observation point in the atmospheric polarization image, (x c ,y c ) is the coordinate of the center point of the atmospheric polarization image, f c is the focal length of the polarized light compass obtained through calibration;

[0110] e v is the projection of the E vector e of the observation point on the v system, expressed as:

[0111]

[0112] Among them, φ is the polarization angle of the observation point, that is, the prior information.

[0113] In this embodiment, the polarization angle of the observation point can be calculated using the Stokes vector method during the process of constructing the polarization vector non-orthogonality error angle model. The Stokes vector contains four parameters S0 = [S1 S2 S3 S4], where S1 represents the total light intensity, S2 is the light intensity difference between the 0° and 90° directions, S3 is the light intensity difference between the 45° and 135° directions, and S4 is the circular polarization component. The intensity of the polarized light after passing through the polarizer is:

[0114]

[0115] Where θ1 is the polarization angle, is the angle between the sensor polarization direction and the system optical axis;

[0116] Since circular polarization components are rare in nature, the S4 component is generally omitted in actual calculations, resulting in a simplified Stokes intensity equation:

[0117]

[0118] When the polarization angle θ1 is 0°, 45°, and 90° respectively, the Stokes parameter of each pixel on the image is:

[0119]

[0120] Without considering circularly polarized light, the polarization angle of each pixel is:

[0121]

[0122] In this embodiment, the specific calculation process of the projection of the sun direction vector on the optical compass coordinate system is:

[0123]

[0124] is the conversion matrix from system b to system c, expressed as:

[0125]

[0126] is the conversion matrix from n-system to c-system, expressed as:

[0127]

[0128] Among them, r0, θ0, and Ψ0 are the carrier roll angle, pitch angle, and heading angle provided by other sensors (such as satellite dual antennas), that is, prior information;

[0129] s n is the sun direction vector in the navigation coordinate system, expressed as:

[0130]

[0131] in, is the azimuth of the sun direction vector in the navigation coordinate system, is the altitude angle of the sun direction vector in the navigation coordinate system. When the time and geographical location are known, It can be obtained through the solar ephemeris, that is, This is also prior information.

[0132] In this embodiment, the specific calculation process of the projection of the observation direction vector on the optical compass coordinate system is:

[0133] v c =[sinγ v ·cosα v sinγ v ·sinα v -cosγ v ] T (18)

[0134] After completing the construction of the polarization vector non-orthogonal error angle model, the observation information of each observation point in the atmospheric polarization image is substituted into the polarization vector non-orthogonal error angle model. The polarization vector non-orthogonal error angle model is solved by combining a series of prior information to estimate the non-orthogonal error angle of each observation point. According to Equation (4), the problem of solving the non-orthogonal error angle can be transformed into a nonlinear programming problem with boundary constraints. Therefore, in the specific implementation process of solving the polarization vector non-orthogonal error angle model in step 2, the interior point method is used to solve the nonlinear optimization problem, which has the advantages of low computational complexity and strong robustness.

[0135] In the specific implementation process, the E vector of each observation point is calculated based on the non-orthogonal error angle, and the sun direction vector is obtained according to the E vector of each observation point, and the heading angle of the carrier is obtained as follows:

[0136] First, substitute the non-orthogonal error angles of each observation point estimated in step 2 into r1, r2, and r3 in equation (3), and then rewrite equation (3) as follows:

[0137] e c -r2·v c =r1·s c +r3·[v c ×]s c (19)

[0138] Among them, [v c ×] is v c The antisymmetric matrix of ;

[0139] Secondly, based on formula (14), the projection s of the sun direction vector on the optical compass coordinate system can be expressed as c Written as:

[0140]

[0141] in, x c are intermediate parameters, r, θ, and Ψ are the actual carrier roll angle, pitch angle, and heading angle, respectively;

[0142] Then, formula (19) can be simplified as:

[0143]

[0144] Among them, E3 is the identity matrix;

[0145] Formula (21) can be simplified as:

[0146]

[0147] in:

[0148] P=(r1·E3+r3·[v c ×]) (25)

[0149] Among them, P is the intermediate parameter;

[0150] So we have:

[0151]

[0152] At the same time and place, different observation points correspond to different E vectors and different observation direction vectors, but the corresponding sun direction vector is unified. Therefore, the projection s of the sun direction vector on the C system can be obtained by using the Lagrange multiplier method to solve the simultaneous equations of all observation points. c , combined with equations (20)-(22), the actual heading angle of the carrier can be obtained as:

[0153]

[0154] or

[0155]

[0156] Among them, x c (1), x c (2) Divided into vector x c The first and second elements in α s is the solar azimuth angle, and π is the ambiguity of the polarized light orientation.

[0157] In a specific implementation, the ambiguity π of the polarization orientation can be removed by the quadrant position of the solar meridian projection or the heading angle difference between adjacent frames.

[0158] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for compensating polarization light orientation error, characterized in that: The steps include: Step 1: Obtain an atmospheric polarization image and construct a polarization vector non-orthogonal error angle model. The process is as follows: Decompose the E vector e of the observation point into the coordinate system composed of the sun direction vector s axis, the observation direction vector v axis and the orthogonal axis composed of v×s: e=r1·s+r2·v+r3·v×s Where r1 = sinη / sinτ, r2 = -sinη / tanτ, r3 = -cosη / sinτ, respectively, are the modulus lengths of the E vector e of the observation point on the three axes, η is the non-orthogonality error angle of the observation point, and τ is the scattering angle; Projecting the E vector e of the observation point into the optical compass coordinate system, we have: yes c =r1·s c +r2·v c +r3·v c ×s c Among them, e c is the projection of the E vector e of the observation point on the optical compass coordinate system, s c is the projection of the sun direction vector on the optical compass coordinate system, v c is the projection of the observation direction vector on the optical compass coordinate system; Let f(η) = r1·s c +r2·v c +r3·v c ×s c -e c As the objective function, the polarization vector non-orthogonal error angle model is Step 2, solving the polarization vector non-orthogonal error angle model to obtain the non-orthogonal error angle of each observation point in the atmospheric polarization image; Step 3: Calculate the E vector of each observation point based on the non-orthogonal error angle, obtain the sun direction vector according to the E vector of each observation point, and obtain the heading angle of the carrier.

2. The polarization light orientation error compensation method according to claim 1, wherein: The projection of the E vector e of the observation point on the optical compass coordinate system is specifically: is the transformation matrix from the observation point coordinate system to the optical compass coordinate system, expressed as: Among them, α v is the azimuth of the observation point in the optical compass coordinate system, γ v is the zenith angle of the observation point in the optical compass coordinate system; e v is the projection of the E vector e of the observation point on the observation point coordinate system, expressed as: in, is the polarization angle of the observation point.

3. The polarization light orientation error compensation method according to claim 1, wherein: The projection of the sun direction vector on the optical compass coordinate system is specifically: is the transformation matrix from the carrier coordinate system to the optical compass coordinate system, expressed as: is the transformation matrix from the navigation coordinate system to the optical compass coordinate system, expressed as: Among them, r0, θ0, and Ψ0 are the carrier roll angle, pitch angle, and heading angle provided by the satellite dual antennas, respectively; s n is the sun direction vector in the navigation coordinate system, expressed as: Where T is the transpose of the matrix, is the azimuth of the sun direction vector in the navigation coordinate system, is the altitude angle of the sun direction vector in the navigation coordinate system.

4. The polarization light orientation error compensation method according to claim 1, wherein: The projection of the observation direction vector on the optical compass coordinate system is specifically: v c =[sinγ v ·cosα v sinγ v ·sinα v -cosγ v ] T Among them, T is the transpose of the matrix, α v is the azimuth of the observation point in the optical compass coordinate system, γ v is the zenith angle of the observation point in the optical compass coordinate system.

5. The polarization light orientation error compensation method according to any one of claims 1 to 4, characterized in that: In step 2, the polarization vector non-orthogonality error angle model is solved based on the interior point method.

6. The method for compensating for polarization light orientation error according to any one of claims 1 to 4, characterized in that: Step 3 is as follows: Decompose the E vector e of the observation point into the coordinate system composed of the sun direction vector s axis, the observation direction vector v axis and the orthogonal axis composed of v×s: e=r1·s+r2·v+r3·v×s Where r1 = sinη / sinτ, r2 = -sinη / tanτ, r3 = -cosη / sinτ, respectively, are the modulus lengths of the E vector e of the observation point on the three axes, η is the non-orthogonality error angle of the observation point, and τ is the scattering angle; Projecting the E vector e of the observation point into the optical compass coordinate system, we have: yes c =r1·s c +r2·v c +r3·v c ×s c Further written as: yes c -r2·v c =r1·s c +r3·[v c ×]s c Among them, e c is the projection of the E vector e of the observation point on the optical compass coordinate system, s c is the projection of the sun direction vector on the optical compass coordinate system, v c is the projection of the observation direction vector on the optical compass coordinate system, [v c ×] is v c The antisymmetric matrix of ; Because there are: in, is the transformation matrix from the carrier coordinate system to the optical compass coordinate system, is the transformation matrix from the navigation coordinate system to the optical compass coordinate system, s n is the sun direction vector in the navigation coordinate system; Then s c for: in, x c are intermediate parameters, r, θ, and v are the actual carrier roll angle, pitch angle, and heading angle, respectively. is the azimuth of the sun direction vector in the navigation coordinate system, is the altitude angle of the sun direction vector in the navigation coordinate system; Further we get: Among them, E3 is the identity matrix; Simplifying to get: P=(r1·E3+r3·[v c ×]) Among them, P is the intermediate parameter; So we have: The actual heading angle of the carrier is: or Among them, x c (1), x c (2) Divided into vector x c The first and second elements in α s is the solar azimuth angle, and π is the ambiguity of the polarized light orientation.

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