CN119001681A - Design method for dihedral angle errors of single corner reflector - Google Patents
Design method for dihedral angle errors of single corner reflector Download PDFInfo
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Abstract
The invention discloses a design method of dihedral angle errors of a single corner reflector, which comprises the following steps: calculating according to the number of the tracks of the ranging target to obtain the variation range of the speed difference angle; constructing a far-field diffraction model based on the dihedral angle error compensation speed difference effect; inputting parameters of a corner reflector and ranging laser and the variation range of the speed difference angle as input conditions to the far-field diffraction model, and performing far-field diffraction simulation on the corner reflector with dihedral angle errors through a Fraunhofer formula in the far-field diffraction model to obtain corresponding far-field energy distribution; and calculating according to the far-field energy distribution to obtain the dihedral angle error of the optimal corner reflector. The dihedral angle error design method provided by the invention has strong universality and can be applied to various laser ranging scenes.
Description
Technical Field
The invention relates to the field of laser ranging, in particular to a design method of dihedral angle errors of a single corner reflector.
Background
The corner reflector is a tetrahedral prism in which three surfaces are perpendicular to each other, called a reflecting surface, and a fourth surface may be divided into a rounded bottom surface and a triangular bottom surface according to whether or not it is cut. When the laser enters the corner reflector through the bottom surface, the laser exits through the bottom surface after three total reflections of the three reflecting surfaces. The direction of the outgoing laser light is exactly opposite to the direction of the incoming laser light. This retro-reflection characteristic is independent of the direction of incidence of the laser light.
When laser light is obliquely incident on the corner reflector array, since it is not known through which corner reflector the echo pulse is reflected back, the laser pulse is widened to introduce a ranging error. Therefore, the monolithic corner reflector has been the major considered corner reflector object at present.
The 100mm bore solid corner reflectors currently developed by university of maryland in the united states have been completed and optical testing has been completed. The current corner reflector design is mainly aimed at lunar laser ranging, the considered corner reflector is a solid corner reflector, default laser has polarization characteristics, and the design method lacks universality.
Disclosure of Invention
In order to solve the technical problems of single target and poor universality in the design of the corner reflectors in the prior art, the invention provides a design method for dihedral angle errors of a single corner reflector, which comprises the following steps:
Calculating according to the number of the tracks of the ranging target to obtain the variation range of the speed difference angle;
constructing a far-field diffraction model based on the dihedral angle error compensation speed difference effect;
Inputting parameters of a corner reflector and ranging laser and the variation range of the speed difference angle as input conditions to the far-field diffraction model, and performing far-field diffraction simulation on the corner reflector with dihedral angle errors through a Fraunhofer formula in the far-field diffraction model to obtain corresponding far-field energy distribution;
and calculating according to the far-field energy distribution to obtain the dihedral angle error of the optimal corner reflector.
As a preferred embodiment, the method for calculating the range of the slip angle according to the number of the tracks of the ranging target includes:
and calculating according to the track number of the ranging target to obtain a linear velocity vector of the ranging target, performing difference between the linear velocity vector and the linear velocity vector of the station rotation, and projecting the linear velocity vector to a direction perpendicular to the ranging target-station vector for calculation to obtain the variation range of the speed difference angle of the ranging target.
As a preferred embodiment, the magnitude of the slip angle is calculated by the following formula:
Wherein v r is the projection of the motion speed of the satellite relative to the station in the direction perpendicular to the ranging target-station vector, and c is the speed of light; the motion speed of the satellite satisfies the vitality formula:
Wherein v is the linear velocity of the satellite revolving around the earth, G is the gravitational constant of the earth, r is the distance from the satellite to the earth centroid, and a is the semi-long axis of the satellite orbit; the station also has a rotational linear velocity on earth that satisfies:
where ω is the angular velocity of earth rotation, RE is the earth radius, Is the latitude where the station is located.
As a preferred scheme, the method for constructing the far-field diffraction model comprises the following steps:
Far field diffraction is calculated by using the Fraunhofer formula, and the specific formula is as follows:
Wherein z 1 represents the distance from the diffraction plane to the viewing plane, x 1,y1 is the abscissa and ordinate of the diffraction plane, respectively, x, y is the abscissa and ordinate of the viewing plane, respectively, wherein the second term is a secondary phase factor, which has no influence on the intensity of light, Is a spherical wave with an amplitude of 1,For the complex amplitude over the diffraction aperture,Is the wave number, thus setThe fraunhofer formula is simplified to:
as a secondary phase factor, the energy distribution of the far-field diffraction light spot is calculated without influence, so that the energy distribution is ignored; the final fraunhofer formula is as follows:
as a preferred scheme, the method for constructing the far-field diffraction model further comprises the following steps: calculating a far-field diffraction image of the corner reflector through wavefront distribution of the diffraction plane; the wavefront distribution of the diffraction plane is quantitatively described by establishing two coordinate systems, specifically:
Establishing a pyramid coordinate system o-xyz through three right-angle sides of the corner reflector, wherein o is the vertex of the corner reflector; establishing a bottom surface coordinate system o ' -x ' y ' z ' on the bottom surface of the corner reflector, wherein o ' is the projection of a vertex on the bottom surface, is also the center of the bottom surface of the corner reflector, the z ' axis is the normal direction of the bottom surface, the y ' axis direction is the projection of the y axis on the bottom surface, and o ' -x ' y ' z ' forms a right-hand system; since the incident light vector and the reflected light vector are symmetrical with respect to the reflecting surface, calculation can be performed by a mirror image conversion method; the Household matrix of the mirror transformation is related to the normal vector of the reflecting surface; in the pyramid coordinate system, normal vectors of the three reflecting surfaces are respectively an x axis, a y axis and a z axis.
As a preferred embodiment, the transformation matrix of the bottom surface coordinate system and the pyramid coordinate system is as follows:
Wherein the method comprises the steps of As a vector in the pyramid coordinate system,Is a vector in the bottom surface coordinate system.
As a preferred scheme, the method for constructing the far-field diffraction model further comprises the following steps:
The far-field diffraction simulation taking the polarization characteristics of laser into consideration is specifically as follows:
For the calculation of polarized light, a jones vector is used to describe linearly polarized light or circularly polarized light; for linearly polarized light, expressed as: θ is the polarization angle of the linearly polarized light, the magnitude of which is the angle between the polarization direction of the linearly polarized light and the x-axis of the coordinate system, expressed as circularly polarized light The + -respectively corresponds to the left-hand and right-hand of the circularly polarized light; the total reflection process changes the phases of s-waves and p-waves only, and therefore this process is represented by a jones matrix: Delta s,δp represents the phase change of s wave and p wave in the process of total reflection;
Expanding the jones vector and the jones matrix to three dimensions;
Decomposing laser to directions perpendicular to an incident surface and parallel to the incident surface, namely s-wave and p-wave, transmitting the laser in the corner reflector, and establishing a coordinate system to quantitatively describe the changes of the directions and phases of the s-wave and the p-wave in the transmission process of the laser in the corner reflector;
For polarized light, p, s, k constitute the right-hand system, and can be derived from the physical meaning of s-waves:
Wherein N represents a normal to an incident surface of the corner reflector;
defining a light vector in a pyramid coordinate system in a light ray tracing process;
Before the Jones matrix is applied to carry out phase superposition on the s wave and the p wave, a matrix is introduced to realize the conversion of a coordinate system; the fresnel formula for each refraction or reflection process is represented by a matrix and the change in the q-th surface light vector is represented by matrix P q:
Because p, s and k form a right-hand system, the matrices are all orthogonal matrices, namely the inverse matrix is equal to the transposed matrix; j q is a three-dimensional jones matrix representing the q-th surface; a s,q and a p,q are respectively the transmission or reflection coefficients of s wave and p wave, and are calculated by a Fresnel formula, and are determined according to the occurring optical process; The matrix is used for converting the light vector in the pyramid coordinate system into the (s q,pq,kq-1) coordinate system; the O out,q matrix functions to convert the light vector in the (s q,pq′,kq) coordinate system into the pyramid coordinate system; s q represents the s-wave component of the refraction or reflection process of the q-th surface; p q represents the p-wave component before refraction or reflection occurs on the q-th surface, obtained by cross-multiplying s q with k q-0; k q-1 represents the emergent light vector of the (q-1) th surface under the pyramid coordinate system, and k q is the same; p q' represents the p-wave component of the outgoing light after the refractive or reflective process has occurred on the q-th surface;
the polarization state change of the laser light after passing through the corner reflector is described by 5 matrix multiplication; the 5 matrices respectively correspond to 5 refraction or reflection processes, and the 5 matrices are respectively marked as a first matrix, a second matrix, a third matrix, a fourth matrix and a fifth matrix, specifically:
The corresponding process of the first matrix is as follows: laser is incident to the bottom surface of the corner reflector to be refracted;
The corresponding processes of the second matrix, the third matrix and the fourth matrix are as follows: the laser light is totally reflected at the three reflecting surfaces;
The fifth matrix corresponds to the process: the laser is refracted through the bottom surface and then is emitted from the inside of the corner reflector to the outside space; the entire calculation process is an iterative process, and the initial definition of s 0,p0 and p 0' is:
p0=s0×k0
p'0=s'0×k'0
k '0 represents the light vector of k 0 after refraction or reflection, P matrices of 5 processes are calculated based on s 0,p0 and P 0', and finally the final exit vector is obtained by multiplying the 5P matrices and then multiplying the incident polarization vector by the left.
As a preferable scheme, the direction and phase change of s wave and p wave in the internal transmission process of the corner reflector are specifically as follows:
In the process of transmitting laser in the corner reflector, the laser can undergo twice refraction and three times of total reflection; the refraction only changes the amplitude of the s wave and the p wave, and does not change the phase of the s wave and the p wave; in the process of three times of total reflection, the amplitudes of the s wave and the p wave are unchanged, and the phase is changed; in each total reflection process, the incident surfaces of the lasers are different, so that the phases and directions of the s wave and the p wave are changed.
As a preferred aspect, the corner reflector includes a solid corner reflector and a hollow corner reflector.
As a preferred embodiment, the method for calculating the optimum corner reflector dihedral angle error from the far-field energy distribution in the variation range of the slip angle includes:
And taking the normalized energy mean value of far-field energy distribution in the variation range of the speed difference angle as an evaluation index to obtain the optimal dihedral angle error design of the corner reflector.
Compared with the prior art, the invention has the following beneficial effects:
The method can obtain the corresponding track number according to different ranging targets, and then design the optimal dihedral angle errors of different aperture corner reflectors by using a far-field diffraction model;
The invention can calculate the relative echo photon number under the condition of considering the factors of the caliber of the corner reflector, dihedral angle error, speed difference angle range, laser incidence angle and the like.
Drawings
Fig. 1 is a flow chart of a design method of dihedral angle errors of a monolithic corner reflector according to the present embodiment;
Fig. 2 is a schematic diagram of a coordinate system provided in the present embodiment.
Detailed Description
The drawings are for illustrative purposes only and are not to be construed as limiting the invention;
it should be understood that the described embodiments are merely some, but not all embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the application, are intended to be within the scope of the embodiments of the present application.
The terminology used in the embodiments of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of embodiments of the application. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any or all possible combinations of one or more of the associated listed items.
When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the application as detailed in the accompanying claims. In the description of the present application, it should be understood that the terms "first," "second," "third," and the like are used merely to distinguish between similar objects and are not necessarily used to describe a particular order or sequence, nor should they be construed to indicate or imply relative importance. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.
Furthermore, in the description of the present application, unless otherwise indicated, "a plurality" means two or more. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a exists alone, A and B exist together, and B exists alone. The character "/" generally indicates that the context-dependent object is an "or" relationship. The application is further illustrated in the following figures and examples.
The invention is further illustrated in the following figures and examples.
Example 1
Referring to fig. 1, the present embodiment provides a method for designing dihedral angle errors of a monolithic corner reflector, the method comprising:
s1: calculating according to the number of the tracks of the ranging target to obtain the variation range of the speed difference angle;
s2: constructing a far-field diffraction model based on the dihedral angle error compensation speed difference effect;
S3: inputting parameters of a corner reflector and ranging laser and the variation range of the speed difference angle as input conditions to the far-field diffraction model, and performing far-field diffraction simulation on the corner reflector with dihedral angle errors through a Fraunhofer formula in the far-field diffraction model to obtain corresponding far-field energy distribution;
Specifically, the input conditions of the far-field diffraction model further comprise the bottom surface caliber of the corner reflector and the ranging laser wavelength.
S4: and calculating according to the far-field energy distribution to obtain the dihedral angle error of the optimal corner reflector.
In a specific embodiment, the method for calculating the range of the slip angle according to the track number of the ranging target comprises the following steps:
and calculating according to the track number of the ranging target to obtain a linear velocity vector of the ranging target, performing difference between the linear velocity vector and the linear velocity vector of the station rotation, and projecting the linear velocity vector to a direction perpendicular to the ranging target-station vector for calculation to obtain the variation range of the speed difference angle of the ranging target.
In a specific embodiment, the magnitude of the slip angle is calculated by the following formula:
Wherein v r is the projection of the motion speed of the satellite relative to the station in the direction perpendicular to the ranging target-station vector, and c is the speed of light; the motion speed of the satellite satisfies the vitality formula:
Wherein v is the linear velocity of the satellite revolving around the earth, G is the gravitational constant of the earth, r is the distance from the satellite to the earth centroid, and a is the semi-long axis of the satellite orbit; the station also has a rotational linear velocity on earth that satisfies:
where ω is the angular velocity of earth rotation, RE is the earth radius, Is the latitude where the station is located.
In a specific embodiment, the method of constructing a far field diffraction model includes:
Far field diffraction is calculated by using the Fraunhofer formula, and the specific formula is as follows:
Wherein z 1 represents the distance from the diffraction plane to the viewing plane, x 1,y1 is the abscissa and ordinate of the diffraction plane, respectively, x, y is the abscissa and ordinate of the viewing plane, respectively, wherein the second term is a secondary phase factor, which has no influence on the intensity of light, Is a spherical wave with an amplitude of 1,For the complex amplitude over the diffraction aperture,Is the wave number, thus setThe fraunhofer formula is simplified to:
as a secondary phase factor, the energy distribution of the far-field diffraction light spot is calculated without influence, so that the energy distribution is ignored; the final fraunhofer formula is as follows:
In a specific embodiment, the method of constructing a far field diffraction model further comprises: calculating a far-field diffraction image of the corner reflector through wavefront distribution of the diffraction plane; the wavefront distribution of the diffraction plane is quantitatively described by establishing two coordinate systems, specifically:
Referring to fig. 2, a pyramid coordinate system o-xyz is established through three right-angle sides of the corner reflector, where o is the vertex of the corner reflector; establishing a bottom surface coordinate system o ' -x ' y ' z ' on the bottom surface of the corner reflector, wherein o ' is the projection of a vertex on the bottom surface, is also the center of the bottom surface of the corner reflector, the z ' axis is the normal direction of the bottom surface, the y ' axis direction is the projection of the y axis on the bottom surface, and o ' -x ' y ' z ' forms a right-hand system; since the incident light vector and the reflected light vector are symmetrical with respect to the reflecting surface, calculation can be performed by a mirror image conversion method; the Household matrix of the mirror transformation is related to the normal vector of the reflecting surface; in the pyramid coordinate system, normal vectors of the three reflecting surfaces are respectively an x axis, a y axis and a z axis.
In a specific embodiment, the transformation matrix of the bottom surface coordinate system and the pyramid coordinate system is as follows:
Wherein the method comprises the steps of As a vector in the pyramid coordinate system,Is a vector in the bottom surface coordinate system.
In a specific embodiment, the corner reflectors include solid corner reflectors and hollow corner reflectors.
In a specific embodiment, the method for calculating the optimal corner reflector dihedral angle error according to the far field energy distribution in the variation range of the slip angle comprises the following steps:
And taking the normalized energy mean value of far-field energy distribution in the variation range of the speed difference angle as an evaluation index to obtain the optimal dihedral angle error design of the corner reflector.
Example 2
Referring to fig. 1, this embodiment can be regarded as a modified or extended embodiment of embodiment 1, specifically:
a method of designing dihedral angle errors for a monolithic corner reflector, the method comprising:
s1: calculating according to the number of the tracks of the ranging target to obtain the variation range of the speed difference angle;
s2: constructing a far-field diffraction model based on the dihedral angle error compensation speed difference effect;
S3: inputting parameters of a corner reflector and ranging laser and the variation range of the speed difference angle as input conditions to the far-field diffraction model, and performing far-field diffraction simulation on the corner reflector with dihedral angle errors through a Fraunhofer formula in the far-field diffraction model to obtain corresponding far-field energy distribution;
Specifically, the input conditions of the far-field diffraction model further comprise the bottom surface caliber of the corner reflector and the ranging laser wavelength.
S4: and calculating according to the far-field energy distribution to obtain the dihedral angle error of the optimal corner reflector.
In a specific embodiment, the method for calculating the range of the slip angle according to the track number of the ranging target comprises the following steps:
and calculating according to the track number of the ranging target to obtain a linear velocity vector of the ranging target, performing difference between the linear velocity vector and the linear velocity vector of the station rotation, and projecting the linear velocity vector to a direction perpendicular to the ranging target-station vector for calculation to obtain the variation range of the speed difference angle of the ranging target.
In a specific embodiment, the magnitude of the slip angle is calculated by the following formula:
Wherein v r is the projection of the motion speed of the satellite relative to the station in the direction perpendicular to the ranging target-station vector, and c is the speed of light; the motion speed of the satellite satisfies the vitality formula:
Wherein v is the linear velocity of the satellite revolving around the earth, G is the gravitational constant of the earth, r is the distance from the satellite to the earth centroid, and a is the semi-long axis of the satellite orbit; the station also has a rotational linear velocity on earth that satisfies:
where ω is the angular velocity of earth rotation, RE is the earth radius, Is the latitude where the station is located.
In a specific embodiment, the method of constructing a far field diffraction model includes:
Far field diffraction is calculated by using the Fraunhofer formula, and the specific formula is as follows:
Wherein z 1 represents the distance from the diffraction plane to the viewing plane, x 1,y1 is the abscissa and ordinate of the diffraction plane, respectively, x, y is the abscissa and ordinate of the viewing plane, respectively, wherein the second term is a secondary phase factor, which has no influence on the intensity of light, Is a spherical wave with an amplitude of 1,For the complex amplitude over the diffraction aperture,Is the wave number, thus setThe fraunhofer formula is simplified to:
as a secondary phase factor, the energy distribution of the far-field diffraction light spot is calculated without influence, so that the energy distribution is ignored; the final fraunhofer formula is as follows:
note that if only the relative distribution of energy is considered, the constant term outside the integral can be ignored, and then the above equation is the same as the form of the two-dimensional fourier transform, so that calculation of fraunhofer diffraction can be regarded as fourier transform of complex amplitude over the diffraction aperture.
In a specific embodiment, the method of constructing a far field diffraction model further comprises: calculating a far-field diffraction image of the corner reflector through wavefront distribution of the diffraction plane; the wavefront distribution of the diffraction plane is quantitatively described by establishing two coordinate systems, specifically:
Referring to fig. 2, a pyramid coordinate system o-xyz is established through three right-angle sides of the corner reflector, where o is the vertex of the corner reflector; establishing a bottom surface coordinate system o ' -x ' y ' z ' on the bottom surface of the corner reflector, wherein o ' is the projection of a vertex on the bottom surface, is also the center of the bottom surface of the corner reflector, the z ' axis is the normal direction of the bottom surface, the y ' axis direction is the projection of the y axis on the bottom surface, and o ' -x ' y ' z ' forms a right-hand system; since the incident light vector and the reflected light vector are symmetrical with respect to the reflecting surface, calculation can be performed by a mirror image conversion method; the Household matrix of the mirror transformation is related to the normal vector of the reflecting surface; in the pyramid coordinate system, normal vectors of the three reflecting surfaces are respectively an x axis, a y axis and a z axis.
In a specific embodiment, the transformation matrix of the bottom surface coordinate system and the pyramid coordinate system is as follows:
Wherein the method comprises the steps of As a vector in the pyramid coordinate system,Is a vector in the bottom surface coordinate system;
It should be noted that the specific principle is to artificially control the three reflecting surfaces of the corner reflector so that the three reflecting surfaces are not strictly vertical any more. When a plane wave is incident on such a corner reflector, the reflected light spot will split to some extent, thereby greatly increasing the number of echo photons at the slip angle. The compensation effect of the method on the large-caliber corner reflector is particularly obvious.
In a specific embodiment, the method of constructing a far field diffraction model further comprises:
The far-field diffraction simulation taking the polarization characteristics of laser into consideration is specifically as follows:
For the calculation of polarized light, a jones vector is used to describe linearly polarized light or circularly polarized light; for linearly polarized light, expressed as: θ is the polarization angle of the linearly polarized light, the magnitude of which is the angle between the polarization direction of the linearly polarized light and the x-axis of the coordinate system, expressed as circularly polarized light The + -respectively corresponds to the left-hand and right-hand of the circularly polarized light; the total reflection process changes the phases of s-waves and p-waves only, and therefore this process is represented by a jones matrix: Delta s,δp represents the phase change of s wave and p wave in the process of total reflection;
Expanding the jones vector and the jones matrix to three dimensions;
Decomposing laser to directions perpendicular to an incident surface and parallel to the incident surface, namely s-wave and p-wave, transmitting the laser in the corner reflector, and establishing a coordinate system to quantitatively describe the changes of the directions and phases of the s-wave and the p-wave in the transmission process of the laser in the corner reflector;
For polarized light, p, s, k constitute the right-hand system, and can be derived from the physical meaning of s-waves:
Wherein N represents a normal to an incident surface of the corner reflector;
Specifically, the incident light vector k q for the q-th surface is actually the refractive/reflective light vector k q-1 for the q-1 th surface. Thus, the ray tracing problem of polarized light is essentially an iterative process, and the output of the last refraction/reflection process is the input of the next refraction/reflection process.
In order to facilitate calculation of the reflected light vector, defining the light vector in a pyramid coordinate system in the process of ray tracing;
since the direction and phase of s-wave and p-wave will change with each reflection. Therefore, the phase change amounts of the three total reflections cannot be simply superimposed as the total amount of phase change;
Before the Jones matrix is applied to carry out phase superposition on the s wave and the p wave, a matrix is introduced to realize the conversion of a coordinate system; the fresnel formula for each refraction or reflection process is represented by a matrix and the change in the q-th surface light vector is represented by matrix P q:
Because p, s and k form a right-hand system, the matrices are all orthogonal matrices, namely the inverse matrix is equal to the transposed matrix; j q is a three-dimensional jones matrix representing the q-th surface; a s,q and a p,q are respectively the transmission or reflection coefficients of s wave and p wave, and are calculated by a Fresnel formula, and are determined according to the occurring optical process; The matrix is used for converting the light vector in the pyramid coordinate system into the (s q,pq,kq-1) coordinate system; the O out,q matrix functions to convert the light vector in the (s q,pq′,kq) coordinate system into the pyramid coordinate system; s q represents the s-wave component of the refraction or reflection process of the q-th surface; p q represents the p-wave component before refraction or reflection occurs on the q-th surface, obtained by cross-multiplying s q with k q-1; k q-1 represents the emergent light vector of the (q-1) th surface under the pyramid coordinate system, and k q is the same; p q' represents the p-wave component of the outgoing light after the refractive or reflective process has occurred on the q-th surface;
the polarization state change of the laser light after passing through the corner reflector is described by 5 matrix multiplication; the 5 matrices respectively correspond to 5 refraction or reflection processes, and the 5 matrices are respectively marked as a first matrix, a second matrix, a third matrix, a fourth matrix and a fifth matrix, specifically:
The corresponding process of the first matrix is as follows: laser is incident to the bottom surface of the corner reflector to be refracted;
The corresponding processes of the second matrix, the third matrix and the fourth matrix are as follows: the laser light is totally reflected at the three reflecting surfaces;
The fifth matrix corresponds to the process: the laser is refracted through the bottom surface and then is emitted from the inside of the corner reflector to the outside space; the entire calculation process is an iterative process, and the initial definition of s 0,p0 and p 0' is:
p0=s0×k0
p'0=s'0×k'0
k '0 represents the light vector of k 0 after refraction or reflection, P matrices of 5 processes are calculated based on s 0,p0 and P 0', and finally the final exit vector is obtained by multiplying the 5P matrices and then multiplying the incident polarization vector by the left.
In a specific embodiment, the direction and phase change of the s wave and the p wave in the process of transmitting the laser inside the corner reflector are specifically as follows:
In the process of transmitting laser in the corner reflector, the laser can undergo twice refraction and three times of total reflection; the refraction only changes the amplitude of the s wave and the p wave, and does not change the phase of the s wave and the p wave; in the process of three times of total reflection, the amplitudes of the s wave and the p wave are unchanged, and the phase is changed; in each total reflection process, the incident surfaces of the lasers are different, so that the phases and directions of the s wave and the p wave are changed.
In a specific embodiment, the corner reflectors include solid corner reflectors and hollow corner reflectors.
In a specific embodiment, the method for calculating the optimal corner reflector dihedral angle error according to the far field energy distribution in the variation range of the slip angle comprises the following steps:
And taking the normalized energy mean value of far-field energy distribution in the variation range of the speed difference angle as an evaluation index to obtain the optimal dihedral angle error design of the corner reflector.
It is to be understood that the above examples of the present invention are provided by way of illustration only and not by way of limitation of the embodiments of the present invention. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the invention are desired to be protected by the following claims.
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