A laser beam riding guidance missile roll angle despinning measurement system and method based on polarized light

Abstract

The application discloses a laser beam riding guidance missile roll angle de-rotation measurement system and method based on polarized light, and belongs to the technical field of missile guidance control. The system comprises a laser irradiator for emitting polarized laser to generate a polarized laser field; a polarized detector assembly is arranged on one side of a target missile body close to the laser irradiator and is located in the polarized laser field together with the target missile body; wherein the polarized detector assembly comprises a four-quadrant detector, an accelerometer, a detection circuit and a signal processing module; a rectangular coordinate system is established in the polarized laser field, and a target missile body coordinate system is established. The application can not only measure the real-time roll angle parameter of the missile relative to the laser information field coordinate system, but also saves the loading process of the missile body reference information, simplifies the system complexity and is highly applicable.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of missile guidance and control, and particularly relates to a laser beam-riding guidance missile roll angle despinning measurement system and method based on polarized light. BACKGROUND

[0002] Intelligent ammunition refers to ammunition integrated with advanced information technology and artificial intelligence technology, which has the ability of autonomous perception, decision-making and task execution. Such ammunition can adjust the flight path in real time during flight to improve the strike accuracy and combat effectiveness. The development of intelligent ammunition is an important direction of modern military technology development, which will greatly improve the combat effectiveness and survivability of weapon systems. Laser beam-riding guided ammunition has become an important development field and direction of intelligent ammunition due to its high guidance accuracy, low cost, small collateral damage, fast reaction time and high combat effectiveness.

[0003] Laser beam-riding guidance is a precise guidance technology mainly used in weapon systems such as missiles and artillery shells. Its working principle is that a laser illuminator aims at the target and continuously emits a laser beam, and a laser receiver located at the tail of the projectile receives the laser signal, controlling the projectile to fly along the center of the laser beam until it hits the target. In the laser beam-riding guidance system, the laser beam is used as a reference for navigation and positioning, and the roll information between the missile axis and the laser field needs to be measured, including roll angle, roll speed, roll direction, etc., to accurately control the attitude of the projectile and make it move towards the center of the laser field.

[0004] Currently, the common schemes for measuring roll angle in laser beam-riding guidance can be divided into two categories. One is based on accelerometer and micro-silicon gyroscope measurement technology, which uses an accelerometer to measure the acceleration of the object and a micro-silicon gyroscope to measure the angular velocity. However, this method has a large measurement error due to the overload problem of the projectile. The other is a measurement method based on geomagnetic / gyro information and GPS, which uses geomagnetic navigation and GPS anti-high overload performance to estimate the roll angle of the projectile combined with gyro information. However, this method requires pre-loading of relevant information for projectile attitude measurement, which increases the complexity of the overall system. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art and provide a laser beam-riding guidance missile roll angle despinning measurement system and method based on polarized light, which can not only measure the real-time roll angle parameters of the missile relative to the laser information field coordinate system, but also eliminate the need for loading projectile reference information, simplify the system complexity, and effectively solve the problems of large error in current roll angle measurement due to overload and other reasons, and GPS cannot be calculated when the signal is disturbed.

[0006] The present application provides the following technical solutions:

[0007] In a first aspect, a polarization-based laser beam guidance missile roll angle de-rotation measurement system is provided, comprising: a laser illuminator configured to emit polarized laser light to generate a polarized laser field; and a polarization detector assembly disposed on a side of a target missile body close to the laser illuminator and located in the polarized laser field together with the target missile body; wherein the polarization detector assembly comprises a four-quadrant detector, an accelerometer, a detection circuit, and a signal processing module; the four-quadrant detector, the detection circuit, and the signal processing module are connected in sequence; the accelerometer is connected to the signal processing module and configured to detect a gravity direction of the target missile body and send the gravity direction to the signal processing module; the four-quadrant detector is provided with four-quadrant polarizers on a surface close to the laser illuminator, each quadrature polarizer generates polarized light signals of different intensities, the four-quadrant detector is configured to convert the quadrature polarized light signals into quadrature electrical signals, the detection circuit is configured to convert the quadrature electrical signals into quadrature digital signals, and the signal processing module is configured to calculate a roll angle and a roll direction of the target missile body based on the quadrature digital signals and the gravity direction of the target missile body; a rectangular coordinate system is established in the polarized laser field, and a target missile body coordinate system is established.

[0008] As an optional technical solution of the present application, the polarization detector assembly further comprises an optical focusing member disposed on a side of the four-quadrant detector close to the laser illuminator and configured to focus the polarized light on the four-quadrant polarizers.

[0009] As an optional technical solution of the present application, the laser illuminator generates polarized laser light through a polarized light source, and the polarized light source adopts polarization-maintaining fiber coupling.

[0010] As an optional technical solution of the present application, the polarization angles of the first to fourth quadrants in the four-quadrant polarizer are respectively denoted as , , and , and the polarization angles of the first to fourth quadrants are sequentially different by 45°. , , and .

[0011] As an optional technical solution of the present application, the detection circuit comprises four branches, the four branches are respectively connected to the quadrants of the four-quadrant detector, each branch comprises a preamplifier, a low-pass filter, an amplifier, and an A / D converter connected in sequence, and the output end of the A / D converter is connected to the signal processing module.

[0012] In a second aspect, a measurement method of the system is provided, comprising: receiving the digital signals of each quadrant of the four-quadrant polarizer and the gravity direction of the target projectile, wherein the digital signals of each quadrant include the light signal intensity of each quadrant of the polarizer;

[0013] calculating the intermediate expression of the roll angle based on the light signal intensity of each quadrant of the polarizer and according to the polarization angles of the first to fourth quadrants which are orthogonal to each other;

[0014] determining the roll angle and the roll direction of the target projectile relative to the polarized laser field according to the intermediate expression of the roll angle and the gravity direction of the target projectile.

[0015] In an optional technical solution of the present application, the light signal intensity of each quadrant of the polarizer is represented as:

[0016] ;

[0017] wherein, I1 represents the light signal intensity of the first quadrant of the polarizer, I2 represents the light signal intensity of the second quadrant of the polarizer, I3 represents the light signal intensity of the third quadrant of the polarizer, I4 represents the light signal intensity of the fourth quadrant of the polarizer, I0 represents the linearly polarized light intensity after atmospheric attenuation, Ia represents the stray light intensity generated by the laser depolarization effect, and wherein,

[0018] In an optional technical solution of the present application, the intermediate expression of the roll angle is calculated based on the light signal intensity of each quadrant of the polarizer and according to the polarization angles of the first to fourth quadrants which are orthogonal to each other, comprising:

[0019] the polarization angles and , and are orthogonal to each other, the light signal intensity of the polarization angles and , and is interacted with the difference value and then compared, and is represented as:

[0020] ;

[0021] ;

[0022] wherein, I1-I2 represents the difference value of the light signal intensity of the polarization angles and , polarization angle and the light signal intensity difference.

[0023] As an optional technical solution of the present application, the roll angle of the target projectile relative to the polarized laser field is determined according to the intermediate expression of the roll angle and the gravity direction of the target projectile, and the roll direction of the target projectile is determined according to the intermediate expression of the roll angle and the gravity direction of the target projectile.

[0024] An angle α between the gravity direction of the target projectile and the negative direction of the longitudinal axis of the target projectile coordinate system is determined, and if the angle α is located between 0 and π / 2, the roll angle of the target projectile is located between 0 and π / 2 or between 3π / 2 and 2π; if the angle α is located between π / 2 and π, the roll angle of the target projectile is located between π / 2 and 3π / 2.

[0025] When I2 / I1 is positive, the roll angle of the target projectile is located between 0 and π / 4 or between 3π / 2 and 7π / 4; when I2 / I1 is negative, the roll angle of the target projectile is located between π / 4 and π / 2 or between 7π / 4 and 2π.

[0026] The unique value of the roll angle is solved according to the polarity of I1 and I2.

[0027] As an optional technical solution of the present application, the roll direction of the target projectile is determined according to the intermediate expression of the roll angle and the gravity direction of the target projectile.

[0028] After the roll angle of the current sampling period is determined, the roll angle of the subsequent sampling period is continuously solved.

[0029] The polarity of the light signal intensity difference I1 and I2 is determined through the roll angles in different sampling periods, and the roll direction is determined according to the polarity of I1 and I2.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] The laser beam guidance missile roll angle unscrambling measurement system based on polarized light provided by the present application can realize the measurement of the roll angle through the polarized detector assembly installed on the projectile, can measure the real-time roll angle parameter of the missile relative to the laser information field coordinate system, saves the loading process of the projectile reference information, simplifies the system complexity, and effectively solves the problems of large error in the measurement of the roll angle due to overload and the incapability of solving when the GPS is interfered by signals. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is the principle diagram of the polarized light recognition in the embodiment of the present application;

[0033] Figure 2 is the structural schematic diagram of the polarized detector assembly in the embodiment of the present application;

[0034] Figure 3 is a schematic diagram of a four-quadrant detector in an embodiment of the present application;

[0035] Figure 4 is a structural diagram of a four-quadrant polarizer in an embodiment of the present application;

[0036] Figure 5 is a schematic diagram of a roll angle in an embodiment of the present application;

[0037] Figure 6 is a diagram of the relationship between the light intensity of each quadrant and the angle in an embodiment of the present application;

[0038] Figure 7 is a diagram of the results of I1, I2, and I2 / I1 in a 2π period in an embodiment of the present application. DETAILED DESCRIPTION

[0039] The present application will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0040] Embodiment 1

[0041] The present embodiment provides a laser beam riding guidance missile roll angle despinning measurement system based on polarized light, as shown in the figure, comprising: a laser irradiator for emitting polarized laser to generate a polarized laser field; a polarized detector assembly arranged on the side of the target missile body close to the laser irradiator, and located in the polarized laser field together with the target missile body. Figure 1

[0042] In the present embodiment, the laser irradiator generates polarized laser through a polarized light source. In order to ensure that the output power of the laser irradiator is as small as possible, the polarized light source adopts polarization maintaining fiber coupling. In the present embodiment, a polarizer with high extinction ratio is arranged in front of the laser irradiator to generate a polarized light source.

[0043] As shown in the figure, the polarized detector assembly comprises an optical focusing member, a four-quadrant detector, an accelerometer, a detection circuit, and a signal processing module. Figure 2

[0044] ​​Specifically, the four-quadrant detector, the detection circuit and the signal processing module are connected in sequence; the accelerometer is connected with the signal processing module, and is used for detecting the gravity direction of the target projectile and sending the gravity direction to the signal processing module. In order to reduce the volume of the system, the four-quadrant detector is provided with four quadrant polarizers close to the surface of the laser irradiator, each quadrant polarizer generates a polarized light signal with different intensity, the four-quadrant detector is used for converting each quadrant polarized light signal into a corresponding quadrant electric signal, the detection circuit is used for converting each quadrant electric signal into a corresponding quadrant digital signal, and the signal processing module is used for calculating the roll angle and the roll direction of the target projectile according to each quadrant digital signal and the gravity direction of the target projectile. The roll angle of the target projectile is calculated by analyzing the difference of the light intensity signals received by the polarizers with different angles. The optical focusing member is arranged on the side of the four-quadrant detector close to the laser irradiator, and is used for focusing the polarized light on the four-quadrant polarizer.

[0045] Further, the polarization angles of the first to fourth quadrants in the four-quadrant polarizer are respectively denoted as 、 、 and , and the polarization angles of the first to fourth quadrants are respectively different by 45°. 、 、 and . When the target projectile is at different angles, each quadrant will respond to different light signal values, and the roll angle of the target projectile is calculated according to the relationship between the light signal values.

[0046] In the embodiment, as shown in Figure 3 and Figure 4 , the polarization angles of the four-quadrant polarizer in the order of 2143 quadrants are respectively 0°, 45°, 90° and-45°.

[0047] The detection circuit includes four branches, and the four branches are respectively connected with each quadrant of the four-quadrant detector. Each branch includes a preamplifier, a low-pass filter, an amplifier and an A / D converter connected in sequence; and the output end of the A / D converter is connected with the signal processing module.

[0048] Specifically, the four-quadrant detector converts the polarized light passing through the four-quadrant polarizer into corresponding electric signals, and the electric signals are respectively sampled and held after passing through the preamplifier, the low-pass filter and the amplifier. The signal processing module sends a synchronous sampling signal to the A / D converter, receives the digital signals converted by the A / D converter and processes the digital signals. According to the relative signal intensity of the four polarization direction detectors, the angular position of the rolling body is calculated.

[0049] In this embodiment, FPGA is used as the signal processing module to provide driving and control signals for the four-quadrant detector and the A / D sampling circuit, and to calculate the roll angle and determine the roll direction of the received sampling information.

[0050] In this embodiment, in order to calculate the roll angle and the roll direction according to the sampling data, a rectangular coordinate system is established in the polarized laser field, and a target projectile coordinate system is established. As shown in the figure, Figure 5 the emitting direction of the polarized laser is defined as being perpendicular to the paper surface and inward, the polarization direction of the polarized laser is taken as the y-axis, and the upward direction is defined as the positive direction, the direction parallel to the paper surface and perpendicular to the y-axis is taken as the x-axis, and the rightward direction is defined as the positive direction, and a rectangular coordinate system xoy is established. At the same time, the target projectile is located at a point z in the rectangular coordinate system, and the target projectile coordinate system AOB is defined, and the downward direction of the gravity of the projectile is defined as being the same as the A' axis of the coordinate system through the initialization of the accelerometer. With the rotation of the projectile, the angle between the A' axis and the direction of the gravity of the projectile is α. The four-quadrant polarizer shown in Figure 5 corresponds to the four quadrants in the AOB coordinate system, and when the target projectile rolls, the angle θ between the target projectile coordinate system AOB and the rectangular coordinate system xoy is the roll angle to be solved.

[0051] Embodiment 2

[0052] On the basis of Embodiment 1, a measurement method is provided in combination with a specific polarization angle. The laser beam is emitted from the laser irradiator and transmitted through an atmospheric channel. The atmospheric channel generally has molecules and suspended particles, and turbulence caused by uneven temperature and air pressure. Each part can change the spatial and instantaneous characteristics of the laser irradiance distribution, including absorption, scattering, intensity fluctuation, and laser depolarization. In summary, the main effects of the atmosphere on the transmission of the laser beam are as follows: one is atmospheric attenuation, and the other is atmospheric turbulence.

[0053] For the current laser irradiator, after long-distance transmission, on the one hand, the laser spot on the receiving plane of the detector will spread to a spot of several meters in size, and the received light intensity of the detector will continue to decay with the distance; on the other hand, the light intensity distribution of the laser spot on the receiving plane is not uniform due to the influence of atmospheric turbulence, and at the same time, due to the laser depolarization effect, part of the light emitted by the laser will become stray light that is not needed by the system. Therefore, in the process of solving the roll angle by polarization, the changes in light intensity and the influence of stray light on the solution need to be considered.

[0054] Considering the above situation, the method specifically includes the following steps:

[0055] Step 1: receiving the digital signals of each quadrant of the four-quadrant polarizer and the gravity direction of the target projectile, wherein the digital signals of each quadrant include the light signal intensity of each quadrant polarizer.

[0056] The light intensity before the optical focusing element is focused to each quadrant polarizer is represented as , represented as:

[0057] ;

[0058] wherein, represents the linearly polarized light intensity after atmospheric attenuation, represents the stray light intensity generated by the laser depolarization effect.

[0059] When the target projectile is in the rolling operation process, the angle between the light transmission axis of the four-quadrant polarizer and the polarization direction of the laser emitted by the laser illuminator is constantly changing. Since each quadrant polarizer is 45° different from each other, according to Malus law I = I0cos 2 (θ)‌, so the light signal intensity of the each quadrant polarizer under polarized laser irradiation is represented as:

[0060] ;

[0061] Substituting = , = , = , = into the above formula, we get:

[0062] .

[0063] The light intensity of each quadrant polarizer is a signal group carrying 1 / 2 I0bottom noise and phase difference π / 4, so the electrical signal generated by the photoelectric conversion is also a signal group carrying 1 / 2 I0bottom noise and phase difference π / 4. As shown in Figure 6 , the relative value of the light signal of each quadrant polarizer under different angles of the rolling body relative to the polarization direction of the illuminator laser.

[0064] Step two: based on the light signal intensity of the each quadrant polarizer, and according to the polarization angle of the first to fourth quadrant which is orthogonal to each other, the intermediate expression of the rolling angle is calculated.

[0065] Since 0° and 90°, 45° and -45° are orthogonal to each other, the difference between 0° and 90°, 45° and -45° is represented as:

[0066] ;

[0067] Further, the ratio of the above two formulas can be obtained:

[0068] ;

[0069] ;

[0070] From the above formula, it is known that, there is a unique solution between (-π / 4, +π / 4). As shown in Figure 7 , I2 / I1 is a periodic function with a period of π / 2, so in the process of the elastic body rotation, four angle values correspond to one value of I2 / I1 obtained by solving the four-quadrant output electric signals, and the next step needs to determine the specific angle value from the four angle values.

[0071] Step three: determining the roll angle and roll direction of the target elastic body relative to the polarized laser field according to the intermediate expression of the roll angle and the gravity direction of the target elastic body.

[0072] The determination step of the roll angle is as follows:

[0073] (1) determining the included angle α between the gravity direction of the target elastic body and the negative direction of the longitudinal axis of the target elastic body coordinate system through the accelerometer, if α is located between 0 and π / 2, the roll angle of the target elastic body is located between 0 and π / 2 or 3π / 2 and 2π, if α is located between π / 2 and π, the roll angle of the target elastic body is located between π / 2 and 3π / 2.

[0074] (2) when I2 / I1 is positive, the roll angle of the target elastic body is located between 0 and π / 4 or 3π / 2 and 7π / 4, when I2 / I1 is negative, the roll angle of the target elastic body is located between π / 4 and π / 2 or 7π / 4 and 2π.

[0075] (3) solving the unique value of the roll angle according to the polarity of I1 and I2. Defining the cosine value of the included angle α of the gravity direction G as g, and dividing the positive and negative polarity of the solving values of I2 / I1, g, I1 and I2 according to the interval range of the roll angle θ, the data shown in Table 1 can be obtained.

[0076] Table 1: The positive and negative polarity of the solving values of I2 / I1, g, I1 and I2 corresponding to the interval range of the roll angle θ

[0077] θ [I1 / I2] g ​ [I2] 0～π / 4 + + + + π / 4～π / 2 - + + - π / 2～3π / 4 + - - - 3π / 4～π - - - + π～5π / 4 + - + + 5π / 4～3π / 2 - - + - 3π / 2～7π / 4 + + - - 7π / 4～2π - + - +

[0078] In summary, according to the solving values of I2 / I1, I1, I2 and the solving value of the gravity direction G of the accelerometer, the roll angle of the elastic body relative to the laser polarization field can be uniquely determined. The calculation of the roll angle by this method can remove the factor of light intensity, without considering the uniformity of the in-plane light intensity and the attenuation of the light caused by the movement of the elastic body. The roll angle can be calculated in real time through the real-time four-quadrant signals, and the influence of stray light on the calculation result is effectively reduced due to the automatic removal of natural light I Z .

[0079] The determination of the roll direction is as follows:

[0080] (1) After confirming the roll angle of the current sampling period, the roll angle in the subsequent sampling period is solved.

[0081] After the roll angle θ1 at t1 is calculated, the roll angle at this moment is θ2 after a sampling period Δt. In the solving process, the change relationship between I1(θ1) and I1(θ2) and between I2(θ1) and I2(θ2) is related to time, and according to the time relationship, the roll direction of the projectile body in the Δt time period can be known.

[0082] (2) The polarity of the light signal intensity difference I1 and I2 is determined through the roll angles in different sampling periods, and the roll direction is confirmed according to the polarity of I1 and I2.

[0083] When the sampling period Δt of the detection system is determined, the roll angle corresponding to one sampling period Δt is also determined. In this embodiment, the angle corresponding to one sampling period Δt changes by π / 8, and the polarity of the solving value of I1 and I2 can be obtained, as shown in Table 2. Then, +, -, and 0 are binary coded, + is set to 1, and -, and 0 are set to 0, and the coding result of Table 3 can be obtained.

[0084] Table 2 Polarity of the solving value of I1 and I2

[0085] 0 π / 8 π / 4 3π / 8 π / 2 5π / 8 3π / 4 7π / 8 π ​ + + 0 - - - 0 + + [I2] 0 + + + 0 - - - 0

[0086] Table 3 Binary coding based on the polarity of the solving value of I1 and I2

[0087] 0 π / 8 π / 4 3π / 8 π / 2 5π / 8 3π / 4 7π / 8 π ​ 1 1 0 0 0 0 0 1 1 [I2] 0 1 1 1 0 0 0 0 0

[0088] As shown in Table 3, only three consecutive samplings are needed to obtain three groups of binary codes of (I1, I2), and the roll direction can be judged. For example, if the roll angle θ1 at t1 is π / 2, the binary code of (I1, I2) corresponding to this moment is (0, 0), and if the codes at t1+Δt and t1+2Δt are (0, 0), (0, 0), it indicates that the roll is in the direction of π / 2--5π / 8--3π / 4; if the codes at t1+Δt and t1+2Δt are (0, 1), (0, 1), it indicates that the roll is in the direction of π / 2--3π / 8--π / 4.

[0089] In addition, after the roll angles at each moment are known, the instantaneous roll angular velocity can be solved, and according to the judgment of the roll direction, the positive and negative directions of the solved roll angular velocity can be given.

[0090] In the description of the present application, it is to be understood by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, only for the convenience of describing the present application and simplifying the description, and not indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0091] In the description of the present application, it should be noted that unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0092] The above is only the preferred embodiment of the present application, it should be pointed out that for ordinary skilled in the art, without departing from the technical principles of the present application, can also make a number of improvements and modifications, these improvements and modifications should be considered as the protection scope of the present application.

Claims

1. A system for measuring the roll angle unrotation of a laser beam-riding guided missile based on polarized light, characterized in that, include: A laser irradiator is used to emit polarized laser light to generate a polarized laser field. The polarization detector assembly is located on the side of the target projectile closest to the laser irradiator, and is situated within the polarization laser field together with the target projectile. The polarization detector assembly includes a four-quadrant detector, an accelerometer, a detection circuit, and a signal processing module; the four-quadrant detector, the detection circuit, and the signal processing module are connected in sequence; the accelerometer is connected to the signal processing module and is used to detect the gravity direction of the target projectile and send it to the signal processing module. The four-quadrant detector has four-quadrant polarizers on its surface near the laser irradiator. Each quadrant polarizer generates polarized light signals of different intensities. The four-quadrant detector is used to convert the polarized light signals of each quadrant into electrical signals of each quadrant. The detection circuit is used to convert the electrical signals of each quadrant into digital signals of each quadrant. The signal processing module is used to calculate the roll angle and roll direction of the target projectile based on the digital signals of each quadrant and the gravity direction of the target projectile. A Cartesian coordinate system is established in the polarized laser field, and a target projectile coordinate system is also established.

2. The laser beam-riding guided missile roll angle unrotation measurement system based on polarized light according to claim 1, characterized in that: The polarization detector assembly also includes an optical focusing element located on the side of the four-quadrant detector near the laser irradiator, used to focus polarized light onto the four-quadrant polarizer.

3. The laser beam-riding guided missile roll angle unrotation measurement system based on polarized light according to claim 1, characterized in that: The laser irradiator generates polarized laser light through a polarized light source, which is coupled with polarization-maintaining fiber.

4. The laser beam-riding guided missile roll angle unrotation measurement system based on polarized light according to claim 1, characterized in that: The polarization angles of the first to fourth quadrants of the four-quadrant polarizer are respectively denoted as: , , and Polarization angles in quadrants one through four , , and The angles differ by 45°.

5. The laser beam-riding guided missile roll angle unrotation measurement system based on polarized light according to claim 1, characterized in that: The detection circuit includes four branches, which are respectively connected to each quadrant of the four-quadrant detector. Each branch includes a preamplifier, a low-pass filter, an amplifier, and an A / D converter connected in sequence. The output of the A / D converter is connected to the signal processing module.

6. A measurement method for the system according to any one of claims 1-5, characterized in that, include: Receive digital signals from each quadrant of the four-quadrant polarizer and the gravity direction of the target projectile, wherein each quadrant digital signal includes the light signal intensity of each quadrant polarizer; Based on the light signal intensity of the polarizers in each quadrant, and according to the polarization angles that are orthogonal to each other in the first to fourth quadrants, an intermediate expression for the roll angle is obtained. Based on the intermediate expression for the roll angle and the gravitational direction of the target projectile, the roll angle and roll direction of the target projectile relative to the polarized laser field are determined.

7. The measurement method according to claim 6, characterized in that: The optical signal intensity of each quadrant polarizer is expressed as follows: ； in, This indicates the light signal intensity of the polarizer in the first quadrant. This indicates the light signal intensity of the polarizer in the second quadrant. Indicates the light signal intensity of the polarizer in the third quadrant. This indicates the light signal intensity of the fourth quadrant polarizer. This represents the intensity of linearly polarized light after atmospheric attenuation. This indicates the intensity of stray light generated by the laser depolarization effect. Indicates the roll angle.

8. The measurement method according to claim 7, characterized in that: Based on the optical signal intensity of the polarizers in each quadrant, and according to the intermediate expression for the roll angle calculated from the orthogonal polarization angles in quadrants one through four, the following is included: The polarization angle and , and They are orthogonal to each other, and the polarization angles are... and , and The difference between the optical signal intensities is taken and then compared, expressed as: ； ； in, Indicates the polarization angle and The difference in optical signal intensity, Indicates the polarization angle and The difference in optical signal intensity.

9. The measurement method according to claim 6, characterized in that: Based on the intermediate expression for the roll angle and the gravitational direction of the target projectile, the roll angle of the target projectile relative to the polarized laser field is determined, including: Determine the angle α between the gravity direction of the target projectile and the negative direction of the longitudinal axis of the target projectile's coordinate system. If α is between 0 and π / 2, the roll angle of the target projectile is between 0 and π / 2 or between 3π / 2 and 2π. If α is between π / 2 and π, the roll angle of the target projectile is between π / 2 and 3π / 2. When I2 / I1 is positive, the roll angle of the target projectile is between 0 and π / 4 or between 3π / 2 and 7π / 4; when I2 / I1 is negative, the roll angle of the target projectile is between π / 4 and π / 2 or between 7π / 4 and 2π. The unique value of the roll angle is determined by the polarity of I1 and I2.

10. The measurement method according to claim 9, characterized in that: Based on the intermediate expression for the roll angle and the gravitational direction of the target projectile, the roll direction of the target projectile relative to the polarized laser field is determined, including: After confirming the roll angle of the current sampling period, continue to solve for the roll angle in subsequent sampling periods; By determining the roll angle under different sampling periods, the polarity of the optical signal intensity difference I1 and I2 is determined, and the roll direction is confirmed based on the polarity of I1 and I2.

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