Laser beam driving guided missile roll angle unwinding measurement system and method based on polarized light

Abstract

The invention discloses a laser beam driving guided missile roll angle unwinding measurement system and method based on polarized light, and belongs to the technical field of missile guidance control. The system comprises a laser irradiator used for emitting polarized laser to generate a polarized laser field; the polarization detector assembly is arranged on the side, close to the laser irradiator, of the target projectile body, and the polarization detector assembly and the target projectile body are jointly located in the polarization laser field; wherein the polarization 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 polarization laser field, and a target projectile body coordinate system is established. The real-time roll angle parameter of the missile relative to the laser information field coordinate system can be measured, the loading process of missile body reference information is omitted, the system complexity is simplified, and the applicability is high.

Description

Technical Field

[0001] The invention belongs to the technical field of missile guidance control, and in particular relates to a roll angle derotation measurement system and method for a laser beam-riding guided missile based on polarized light. Background Art

[0002] Intelligent ammunition refers to ammunition that integrates advanced information technology and artificial intelligence technology, giving it the ability to autonomously perceive, make decisions and execute tasks. This type of ammunition can adjust the flight path in real time during flight to improve strike accuracy and combat effectiveness. The development of intelligent ammunition is an important direction for the development of modern military technology, which will greatly improve the combat effectiveness and survivability of weapon systems. Among them, laser beam-riding guided ammunition has become an important development field and direction of intelligent ammunition due to its advantages of high guidance accuracy, low cost, small collateral damage, fast response time and high combat effectiveness.

[0003] Laser beam riding guidance is a precision guidance technology mainly used in weapon systems such as missiles and artillery shells. Its working principle is to aim at the target through a laser illuminator and continuously emit a laser beam. The laser receiver located at the tail of the missile receives the laser signal and controls the missile 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. The missile needs to measure the roll information between the missile axis and the laser field, including the roll angle, roll speed, roll direction, etc., to accurately control the missile's posture and make it move toward the center of the laser field.

[0004] At present, the commonly used solutions for measuring the roll angle in laser beam riding guidance can be divided into two categories. One is the measurement technology based on accelerometers and micro-silicon gyroscopes. This technology uses accelerometers and micro-silicon gyroscopes to measure the roll angle. Accelerometers can measure the acceleration of objects, while micro-silicon gyroscopes can measure 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 / gyroscope information and GPS. This method uses geomagnetic navigation and GPS's high overload resistance, combined with gyroscope information to estimate the roll angle of the projectile. However, this method requires the relevant information to be loaded in advance when measuring the projectile's attitude, which increases the complexity of the overall system. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a roll angle derotation measurement system and method for a laser beam-riding guided missile 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 save the loading process of the missile body reference information, simplify the system complexity, and effectively solve the current problems of large errors in roll angle measurement due to overload and the inability to resolve when GPS is interfered with by signals.

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

[0007] In a first aspect, a roll angle derotation measurement system for a laser beam-riding guided missile based on polarized light is provided, comprising: a laser illuminator, for emitting polarized laser light to generate a polarized laser field; a polarization detector assembly, arranged on a side of a target missile body close to the laser illuminator, and located together with the target missile body in the polarized laser field; 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, for detecting the gravity direction of the target missile body and sending it to the signal processing module; a four-quadrant polarizer is arranged on a surface of the four-quadrant detector close to the laser illuminator, each quadrant polarizer generates a polarized light signal of different intensity, the four-quadrant detector is used to convert each quadrant polarized light signal into each quadrant electrical signal, the detection circuit is used to convert each quadrant electrical signal into each quadrant digital signal, the signal processing module is used to calculate the roll angle and roll direction of the target missile body according to each quadrant digital signal 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 invention, the polarization detector assembly further includes an optical focusing component, which is disposed on a side of the four-quadrant detector close to the laser illuminator and is used to focus the polarized light on the four-quadrant polarizer.

[0009] As an optional technical solution of the present invention, the laser irradiator generates polarized laser light through a polarized light source, and the polarized light source is coupled with a polarization-maintaining optical fiber.

[0010] As an optional technical solution of the present invention, the polarization angles of the first to fourth quadrants of the four-quadrant polarizer are respectively recorded as , , and , polarization angles of quadrants 1 to 4 , , and The difference is 45° respectively.

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

[0012] In a second aspect, a measurement method of the system of the first aspect is provided, comprising: receiving 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;

[0013] Based on the light signal intensity of the polarizers in each quadrant, and according to the polarization angles in quadrants one to four that are orthogonal to each other, an intermediate expression of the roll angle is calculated;

[0014] The rolling angle and rolling direction of the target projectile relative to the polarized laser field are determined according to the intermediate expression of the rolling angle and the gravity direction of the target projectile.

[0015] As an optional technical solution of the present invention, the optical signal intensity of each quadrant polarizer is expressed as:

[0016] ;

[0017] in, represents the optical signal intensity of the first quadrant polarizer, represents the optical signal intensity of the second quadrant polarizer, represents the optical signal intensity of the third quadrant polarizer, represents the optical signal intensity of the fourth quadrant polarizer, represents the intensity of linearly polarized light attenuated by the atmosphere, represents the intensity of stray light generated by laser depolarization effect, Indicates the roll angle.

[0018] As an optional technical solution of the present invention, based on the light signal intensity of the polarizers in each quadrant, and according to the polarization angles in quadrants one to four that are orthogonal to each other, an intermediate expression of the roll angle is calculated, including:

[0019] The polarization angle and , and They are orthogonal to each other, and the polarization angle and , and The difference of the optical signal intensities is expressed as:

[0020] ;

[0021] ;

[0022] in, Indicates the polarization angle and The difference in optical signal intensity is Indicates the polarization angle and The difference in optical signal strength.

[0023] As an optional technical solution of the present invention, 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, including:

[0024] Determine the angle α between the gravity direction of the target projectile and the negative direction of the longitudinal axis of the target projectile 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.

[0025] 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.

[0026] The unique value of the roll angle is solved based on the polarities of I1 and I2.

[0027] As an optional technical solution of the present invention, the rolling direction of the target projectile relative to the polarized laser field is determined according to the intermediate expression of the rolling angle and the gravity direction of the target projectile, including:

[0028] After confirming the roll angle of the current sampling period, continue to solve the roll angle in the subsequent sampling period;

[0029] The polarities of the optical signal intensity differences I1 and I2 are determined by the roll angles at different sampling periods, and the roll direction is confirmed according to the polarities of I1 and I2.

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

[0031] The roll angle derotation measurement system for a laser beam-riding guided missile based on polarized light provided by the present invention can achieve the measurement of the roll angle by means of a polarization detector assembly installed on the missile body. It can not only measure the real-time roll angle parameters of the missile relative to the laser information field coordinate system, but also save the loading process of the missile body reference information, simplify the system complexity, and effectively solve the problems of large errors in the current roll angle measurement due to overload and the inability to solve when the GPS is interfered with by signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of polarized light recognition in an embodiment of the present invention;

[0033] Figure 2 is a schematic structural diagram of a polarization detector assembly in an embodiment of the present invention;

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

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

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

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

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

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

[0040] Example 1

[0041] This embodiment provides a roll angle derotation measurement system for a laser beam-riding guided missile based on polarized light. Figure 1 As shown, it includes: a laser illuminator for emitting polarized laser to generate a polarized laser field; a polarization detector assembly, which is arranged on a side of the target projectile close to the laser illuminator and is located together with the target projectile in the polarized laser field.

[0042] In this embodiment, the laser irradiator generates polarized laser light 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 is coupled with a polarization-maintaining fiber. In this embodiment, a polarizer with a high extinction ratio is arranged in front of the laser irradiator to generate a polarized light source.

[0043] like Figure 2 As shown, the polarization detector assembly includes an optical focusing component, a four-quadrant detector, an accelerometer, a detection circuit and a signal processing module.

[0044] Specifically, 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. In order to reduce the volume of the system, the surface of the four-quadrant detector close to the laser illuminator is provided with a four-quadrant polarizer, each quadrant polarizer generates a polarized light signal of different intensity, the four-quadrant detector is used to convert each quadrant polarized light signal into each quadrant electrical signal, the detection circuit is used to convert each quadrant electrical signal into each quadrant digital signal, the signal processing module is used to calculate the roll angle and roll direction of the target projectile according to each quadrant digital signal and the gravity direction of the target projectile, and the roll angle of the target projectile is calculated by analyzing the difference in light intensity signals received by polarizers at different angles. The optical focusing component is provided on the side of the four-quadrant detector close to the laser illuminator, and is used to focus the polarized light on the four-quadrant polarizer.

[0045] Furthermore, the polarization angles of the first to fourth quadrants of the four-quadrant polarizer are respectively recorded as , , and , polarization angles of quadrants 1 to 4 , , and When the target missile is at different angles, each quadrant will respond to different light signal values, and the rolling angle of the target missile is calculated based on the relationship between the light signal values.

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

[0047] The detection circuit includes four branches, which are respectively connected to the quadrants 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 end of the A / D converter is connected to a signal processing module.

[0048] Specifically, the four-quadrant detector converts the polarized light passing through the four-quadrant polarizer into a corresponding electrical signal, which is sampled and held after passing through a preamplifier, a low-pass filter, and an amplifier. The signal processing module sends a synchronous sampling signal to the A / D converter and receives the digital signal after A / D conversion for processing. The angular position of the roller is calculated based on the relative signal strengths of the detectors in the four polarization directions.

[0049] In this embodiment, FPGA is used as a signal processing module to provide drive and control signals for the four-quadrant detector and the A / D sampling circuit, and also 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 roll direction based on the sampled data, a rectangular coordinate system is established in the polarized laser field, and a target missile body coordinate system is established. Figure 5 As shown, the emission direction of the polarized laser is defined as perpendicular to the paper surface, the polarization direction of the polarized laser is taken as the y-axis, and upward 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 rightward 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 is defined as AOB. The initialization of the accelerometer defines that the downward gravity of the projectile is in the same direction as the A' axis of the coordinate system. As the projectile rotates, the angle between the A' axis and the direction of the gravity of the projectile is α. Figure 5 The four-quadrant polarizers shown in the figure correspond to the four quadrants of the AOB coordinate system respectively. When the target projectile rolls, the angle θ between the target projectile coordinate system AOB and the rectangular coordinate system xoy is the required rolling angle.

[0051] Example 2

[0052] This embodiment provides a measurement method based on the embodiment 1 in combination with the specific polarization angle. The laser beam is emitted from the laser irradiator and transmitted through the atmospheric channel. The atmospheric channel generally contains molecules and suspended particles as well as turbulence caused by uneven temperature and air pressure. Each of them can change the distribution space and instantaneous characteristics of the laser irradiance. These changes include absorption, scattering, intensity fluctuations and laser depolarization. In general, the atmosphere has the following two effects on the transmission of the laser beam: one is atmospheric attenuation, and the other is atmospheric turbulence.

[0053] For current laser illuminators, after long-distance transmission, on the one hand, the laser spot on the receiving plane where the detector is located will spread to a spot of several meters in size, and the light intensity that the detector can receive will continue to decay as the detector moves away; 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 due to the laser depolarization effect, part of the light emitted by the laser will become stray light that the system does not need. Therefore, in the process of solving the roll angle through polarization, it is necessary to consider the change of light intensity and the influence of stray light on the solution.

[0054] Taking the above situation into consideration, the present method specifically comprises the following steps:

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

[0056] The light intensity before the polarizer in each quadrant after being focused by the optical focusing component is expressed as , expressed as:

[0057] ;

[0058] in, represents the intensity of linearly polarized light attenuated by the atmosphere, Indicates the intensity of stray light generated by laser depolarization effect.

[0059] When the target missile is rolling, the angle between the transmission axis of the four-quadrant polarizer and the polarization direction of the laser emitted by the laser irradiator is constantly changing. Since the polarizers in each quadrant differ by 45°, according to Malus's law, I=I0cos 2 (θ)‌, so the light signal intensity of each quadrant polarizer under polarized laser irradiation is expressed as:

[0060] ;

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

[0062] .

[0063] The light intensity of each quadrant polarizer is a signal group with a 1 / 2I0 background noise and a phase difference of π / 4, so the size of the electrical signal generated by its photoelectric conversion is also a signal group with a 1 / 2 I0 background noise and a phase difference of π / 4. Figure 6 As shown, the relative values ​​of the optical signals of each quadrant polarizer are shown when the roller is at different angles relative to the polarization direction of the irradiator laser.

[0064] Step 2: Based on the light signal intensity of the polarizers in each quadrant, and according to the polarization angles in quadrants one to four that are orthogonal to each other, an 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 expressed as:

[0066] ;

[0067] Furthermore, by ratioing the above two equations, we can get:

[0068] ;

[0069] ;

[0070] From the above formula, we can know that There is a unique solution between (-π / 4, +π / 4). Figure 7 As shown, I2 / I1 is a periodic function with a period of π / 2. Therefore, during the rotation of the projectile, the electrical signals output from the four quadrants are solved to obtain an I2 / I1 value corresponding to four angle values. The next step is to determine the specific angle value from these four angles.

[0071] Step 3: Determine the roll angle and 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.

[0072] The steps to determine the roll angle are as follows:

[0073] (1) Determine the angle α between the gravity direction of the target projectile and the negative direction of the longitudinal axis of the target projectile coordinate system by using an accelerometer. 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.

[0074] (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;

[0075] (3) The unique value of the roll angle is solved according to the polarity of I1 and I2. The cosine value of the angle α in the gravity direction G is defined as g, and the positive and negative polarities of the solution values ​​of I2 / I1, g, I1, and I2 are divided according to the range of the roll angle θ to obtain the data shown in Table 1.

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

[0077] θ <![CDATA[I1 / I2]]> g <![CDATA[I1]]> <![CDATA[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, the roll angle of the projectile relative to the laser polarization field can be uniquely determined based on the solution values ​​of I2 / I1, I1, I2 and the solution value of the accelerometer for the gravity direction G. The roll angle calculated by this method can remove the factor of light intensity, without considering the uniformity of light intensity in the plane and the attenuation of light caused by the movement of the projectile. Instant settlement can be performed through the real-time four-quadrant signal. At the same time, the difference will automatically remove the natural light I Z , effectively reducing the impact of stray light on the calculation results.

[0079] The steps to determine the rolling direction are as follows:

[0080] (1) After confirming the roll angle of the current sampling period, continue to solve the roll angle in the subsequent sampling periods.

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

[0082] (2) Determine the polarity of the optical signal intensity difference I1 and I2 through the roll angle at different sampling periods, and confirm the roll direction based on 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 polarities of the solution values ​​of I1 and I2 can be obtained, as shown in Table 2. Then +, - and 0 are binary-coded, and + is set to represent 1, - and 0 to represent 0, and the coding results in Table 3 can be obtained.

[0084] Table 2 Polarity of the calculated values ​​of I1 and I2

[0085] 0 π / 8 π / 4 3π / 8 π / 2 5π / 8 3π / 4 7π / 8 π <![CDATA[I1]]> + + 0 - - - 0 + + <![CDATA[I2]]> 0 + + + 0 - - - 0

[0086] Table 3 Binary encoding based on the polarity of the calculated values ​​of I1 and I2

[0087] 0 π / 8 π / 4 3π / 8 π / 2 5π / 8 3π / 4 7π / 8 π <![CDATA[I1]]> 1 1 0 0 0 0 0 1 1 <![CDATA[I2]]> 0 1 1 1 0 0 0 0 0

[0088] As shown in Table 3, it is only necessary to continuously sample three times to obtain three sets of (I1, I2) binary codes to determine the rolling direction. For example: if the rolling angle θ1 at time t1 is π / 2, the corresponding (I1, I2) binary code is (0, 0). If the codes at time t1+Δt and time t1+2Δt are (0, 0) and (0, 0), it indicates that the rolling is along the direction of π / 2--5π / 8--3π / 4; if the codes at time t1+Δt and time t1+2Δt are (0, 1) and (0, 1), it indicates that the rolling is along the direction of π / 2--3π / 8--π / 4.

[0089] In addition, after the rolling angle at each moment is known, the instantaneous rolling angular velocity can be calculated. At the same time, according to the judgment of the rolling direction, the calculated rolling angular velocity can be assigned a positive or negative direction.

[0090] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0091] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0092] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A roll angle derotation measurement system for a laser beam-riding guided missile based on polarized light, characterized in that: include: A laser irradiator, used for emitting polarized laser light to generate a polarized laser field; A polarization detector assembly is arranged on a side of the target projectile close to the laser irradiator and is located together with the target projectile in the polarization laser field; Wherein, 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 to detect the gravity direction of the target projectile and send it to the signal processing module; The surface of the four-quadrant detector close to the laser irradiator is provided with a four-quadrant polarizer, each quadrant polarizer generates a polarized light signal of different strength, the four-quadrant detector is used to convert the polarized light signal of each quadrant into an electrical signal of each quadrant, the detection circuit is used to convert the electrical signal of each quadrant into a digital signal of each quadrant, and the signal processing module is used to calculate the roll angle and roll direction of the target projectile according to the digital signal of each quadrant and the gravity direction of the target projectile; A rectangular coordinate system is established in the polarized laser field, and a target missile body coordinate system is established.

2. The roll angle derotation measurement system for a laser beam-riding guided missile based on polarized light according to claim 1, characterized in that: The polarization detector assembly also includes an optical focusing component, which is arranged on a side of the four-quadrant detector close to the laser illuminator and is used to focus the polarized light on the four-quadrant polarizer.

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

4. The roll angle derotation measurement system for a laser beam-riding guided missile 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 of quadrants 1 to 4 , , and The difference is 45° respectively.

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

6. A measurement method of the system according to any one of claims 1 to 5, characterized in that: include: Receiving 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; Based on the light signal intensity of the polarizers in each quadrant, and according to the polarization angles in quadrants one to four that are orthogonal to each other, an intermediate expression of the roll angle is calculated; According to the intermediate expression of the roll angle and the gravity 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 measuring method according to claim 6, characterized in that: The optical signal intensity of each quadrant polarizer is expressed as: ； in, represents the optical signal intensity of the first quadrant polarizer, represents the optical signal intensity of the second quadrant polarizer, represents the optical signal intensity of the third quadrant polarizer, represents the optical signal intensity of the fourth quadrant polarizer, represents the intensity of linearly polarized light attenuated by the atmosphere, represents the intensity of stray light generated by laser depolarization effect, Indicates the roll angle.

8. The measuring method according to claim 7, characterized in that: Based on the light signal intensity of the polarizers in each quadrant, and according to the polarization angles in quadrants 1 to 4 that are orthogonal to each other, an intermediate expression of the rolling angle is calculated, including: The polarization angle and , and They are orthogonal to each other, and the polarization angle and , and The difference of the optical signal intensities is expressed as: ； ； in, Indicates the polarization angle and The difference in optical signal intensity is Indicates the polarization angle and The difference in optical signal strength.

9. The measuring method according to claim 6, characterized in that: According to the intermediate expression of the roll angle and the gravity 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 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 solved based on the polarities of I1 and I2.

10. The measuring method according to claim 9, characterized in that: According to the intermediate expression of the roll angle and the gravity 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 the roll angle in the subsequent sampling period; The polarities of the optical signal intensity differences I1 and I2 are determined by the roll angles at different sampling periods, and the roll direction is confirmed according to the polarities of I1 and I2.

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