A method for measuring angle within insect radar beam based on target echo amplitude modulation

Abstract

The present invention relates to an insect radar beam angle measurement method based on target echo amplitude modulation, belonging to the field of insect radar technology. First, an echo signal amplitude model of an insect crossing a radar beam is constructed to generate an ideal echo amplitude sequence, and then an optimization function is established in combination with the measured echo amplitude sequence, with the echo amplitude shape as a constraint, to directly solve the distance and flight direction of the insect from the central axis of the beam when entering the beam, and finally solve the position of the insect in the beam. The present invention can estimate the target position from the echo amplitude change trend when the radar has no angle measurement function, and is used to solve the problem that the radar scattering cross-sectional area (RCS) measurement is too small when the insect deviates from the center of the radar beam, thereby improving the accuracy of insect body size parameter inversion, helping to improve the accuracy of migratory insect species identification and predict the outbreak of pests and diseases.

Description

Technical Field

[0001] The invention relates to the technical field of insect radars, and in particular to an insect radar beam-internal angle measurement method based on target echo amplitude modulation. Background Art

[0002] Insect radar is an effective tool for studying migratory insects. Based on the measurement results of insect radar, the body length, weight, body width, wing beat frequency, horizontal speed, direction and other parameters of insects can be inverted. Based on the inverted insect parameters, migratory insects can be identified and their trajectories predicted, which is of great significance for studying the behavior of migratory insects and preventing migratory pests and diseases.

[0003] RCS (Radar Cross Section) is one of the most important radar target characteristics. Current insect radars realize body parameter inversion based on insect RCS, and accurate RCS measurement is of great significance.

[0004] For insect radars without in-beam angle measurement function, when the insect deviates from the center of the beam, the target's position in the beam cannot be determined, resulting in a smaller measured insect RCS, which in turn causes the inverted body size parameters to be smaller, making it more difficult to identify the insect species. Summary of the invention

[0005] The purpose of the present invention is to provide an insect radar beam angle measurement method based on target echo amplitude modulation, so as to determine the position of the insect in the beam when the radar has no angle measurement function, solve the problem of small insect RCS measurement, and improve the inversion accuracy of insect body parameters.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] An insect radar beam angle measurement method based on target echo amplitude modulation, comprising:

[0008] Constructing an angle model of the insect's deviation from the center of the beam; the angle model is a function of the angle of the insect's deviation from the center axis of the beam with respect to the distance, flight direction, and time of the insect's deviation from the center axis of the beam when the insect just enters the beam;

[0009] According to the angle model, an amplitude model of the echo signal of the insect passing through the radar beam is established;

[0010] Substituting the time series of insect flight measured by radar into the echo signal amplitude model to generate an ideal echo amplitude sequence;

[0011] According to the ideal echo amplitude sequence and the echo amplitude sequence actually measured by the radar, an optimization function is established with the echo amplitude shape as a constraint;

[0012] A genetic algorithm is used to solve the optimization function to determine the distance and flight direction of the insect from the central axis of the beam when the insect just enters the beam;

[0013] According to the time sequence of the insect's flight measured by radar and the distance and flight direction of the insect's deviation from the beam center axis when it just enters the beam, the angle model is used to obtain the angle sequence of the insect's deviation from the beam center during its crossing of the beam, thereby determining the insect's position in the beam.

[0014] Optionally, the angle model of the insect deviating from the beam center is:

[0015]

[0016] Among them, θ(t) is the angle of the insect's deviation from the beam center at time t, r(t) is the distance from the insect to the beam center axis at time t, and R(t) is the distance from the insect to the radar at time t;

[0017] Where r0 is the distance the insect deviates from the center axis of the beam when it first enters the beam, L(t) is the flight distance of the insect at time t, and L(t) = V h t,V h is the horizontal speed of the insect’s flight, and β is the flight direction of the insect.

[0018] Optionally, the amplitude model of the echo signal of the insect passing through the radar beam is:

[0019]

[0020] Among them, S r (t) is the echo signal amplitude of the insect at time t, G0 is the gain on the central axis of the beam, k is a constant, θ 1 / 2 is the half-power beamwidth, and σ is the radar scattering cross-section of the insect.

[0021] Optionally, according to the ideal echo amplitude sequence and the echo amplitude sequence actually measured by the radar, an optimization function is established with the echo amplitude shape as a constraint, specifically including:

[0022] Determine a ratio sequence of the ideal echo amplitude sequence and the echo amplitude sequence actually measured by the radar;

[0023] According to the ratio sequence, taking the echo amplitude shape as a constraint, the optimization function is established as in, is the estimated value of the distance r0 that the insect deviates from the central axis of the beam when it first enters the beam, is the estimated value of the insect's flight direction β, std() is the standard deviation, S d is a ratio sequence.

[0024] Optionally, the using of a genetic algorithm to solve the optimization function to determine the distance and flight direction of the insect from the central axis of the beam when it just enters the beam specifically includes:

[0025] A genetic algorithm is used to solve the optimization function once to obtain the optimal solution of r0cosβ;

[0026] Combined with the optimal solution of r0cosβ, a genetic algorithm is used to perform a secondary solution on the optimization function to obtain the optimal solution of the distance r0 that the insect deviates from the central axis of the beam when it just enters the beam and the optimal solution of the flight direction β.

[0027] An insect radar beam in-beam angle measurement system based on target echo amplitude modulation, comprising:

[0028] An angle model building module, used to build an angle model of the insect's deviation from the center of the beam; the angle model is a function of the angle of the insect's deviation from the center axis of the beam and the distance, flight direction and time of the insect's deviation from the center axis of the beam when the insect just enters the beam;

[0029] An amplitude model building module is used to build an amplitude model of the echo signal of the insect passing through the radar beam according to the angle model;

[0030] An amplitude sequence generation module is used to substitute the time sequence of insect flight measured by radar into the echo signal amplitude model to generate an ideal echo amplitude sequence;

[0031] An optimization function establishment module is used to establish an optimization function based on the ideal echo amplitude sequence and the echo amplitude sequence actually measured by the radar, taking the echo amplitude shape as a constraint;

[0032] A flight direction determination module, used to solve the optimization function using a genetic algorithm to determine the distance and flight direction of the insect from the central axis of the beam when it just enters the beam;

[0033] The position determination module is used to obtain the angle sequence of the insect's deviation from the center of the beam when it crosses the beam based on the time sequence of the insect's flight measured by the radar and the distance and flight direction of the insect's deviation from the center axis of the beam when it just enters the beam, and use the angle model to determine the position of the insect in the beam.

[0034] Optionally, the angle model of the insect deviating from the beam center is:

[0035]

[0036] Among them, θ(t) is the angle of the insect's deviation from the beam center at time t, r(t) is the distance from the insect to the beam center axis at time t, and R(t) is the distance from the insect to the radar at time t;

[0037] Where r0 is the distance the insect deviates from the center axis of the beam when it first enters the beam, L(t) is the flight distance of the insect at time t, and L(t) = V h t,V h is the horizontal speed of the insect’s flight, and β is the flight direction of the insect.

[0038] Optionally, the amplitude model of the echo signal of the insect passing through the radar beam is:

[0039]

[0040] Among them, S r (t) is the echo signal amplitude of the insect at time t, G0 is the gain on the central axis of the beam, k is a constant, θ 1 / 2 is the half-power beamwidth, and σ is the radar scattering cross-section of the insect.

[0041] Optionally, the optimization function establishment module specifically includes:

[0042] A ratio sequence determination submodule, used to determine a ratio sequence between the ideal echo amplitude sequence and the echo amplitude sequence actually measured by the radar;

[0043] The optimization function establishment submodule is used to establish the optimization function according to the ratio sequence and the echo amplitude shape as a constraint: in, is the estimated value of the distance r0 that the insect deviates from the central axis of the beam when it first enters the beam, is the estimated value of the insect's flight direction β, std() is the standard deviation, S d is a ratio sequence.

[0044] Optionally, the flight direction determination module specifically includes:

[0045] A primary solution submodule, used to solve the optimization function once using a genetic algorithm to obtain the optimal solution of r0cosβ;

[0046] The secondary solution submodule is used to combine the optimal solution of r0cosβ and use a genetic algorithm to perform a secondary solution on the optimization function to obtain the optimal solution of the distance r0 that the insect deviates from the central axis of the beam when it just enters the beam and the optimal solution of the flight direction β.

[0047] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0048] The present invention discloses an insect radar beam angle measurement method based on target echo amplitude modulation. First, an echo signal amplitude model of an insect crossing a radar beam is constructed to generate an ideal echo amplitude sequence. Then, an optimization function is established in combination with the measured echo amplitude sequence and with the echo amplitude shape as a constraint to directly solve the distance and flight direction of the insect from the central axis of the beam when the insect enters the beam, and finally the position of the insect in the beam is solved. The present invention can estimate the target position from the echo amplitude change trend when the radar has no angle measurement function, and is used to solve the problem that the radar scattering cross-sectional area (RCS) measurement is too small when the insect deviates from the center of the radar beam, thereby improving the accuracy of the inversion of the insect body size parameters, which is helpful to improve the accuracy of the identification of migratory insect species and predict the outbreak of pests and diseases. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0050] Figure 1 A flow chart of a method for measuring angles within an insect radar beam based on target echo amplitude modulation provided by an embodiment of the present invention;

[0051] Figure 2 A schematic diagram of an insect passing through a radar beam provided by an embodiment of the present invention;

[0052] Figure 3 A horizontal projection of a three-dimensional trajectory of an insect provided by an embodiment of the present invention;

[0053] Figure 4 A comparison diagram of the estimated value and true value distribution of r0cosβ obtained by the first solution under 1000 simulations provided by an embodiment of the present invention;

[0054] Figure 5 A relative error distribution diagram of the estimation result of r0cosβ obtained by the first solution under 1000 simulations provided by an embodiment of the present invention;

[0055] Figure 6 The absolute error distribution diagram of the estimation of θ obtained by the second solution under 1000 simulations provided by the embodiment of the present invention;

[0056] Figure 7 This is a distribution diagram of the average relative error of θ estimation obtained by the second solution under 1000 simulations provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] The purpose of the present invention is to provide an insect radar beam angle measurement method based on target echo amplitude modulation, so as to determine the position of the insect in the beam when the radar has no angle measurement function, solve the problem of small insect RCS measurement, and improve the inversion accuracy of insect body parameters.

[0059] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0060] The embodiment of the present invention provides an insect radar beam angle measurement method based on target echo amplitude modulation, such as Figure 1 As shown, including:

[0061] Step S1, constructing an angle model of the insect's deviation from the beam center.

[0062] The angle model is the angle at which the insect deviates from the central axis of the beam as a function of the distance the insect deviates from the central axis of the beam when it first enters the beam, the flight direction, and the time.

[0063] Figure 2 Schematic diagram of an insect passing through a radar beam. Figure 4 is the horizontal projection of the insect's three-dimensional trajectory. Point O is the radar position, O' is the intersection of the plane at the height of the insect and the central axis of the beam, OO' is the central axis of the beam, point A is the position where the insect enters the beam, r0 is the length of O'A, that is, the distance the insect deviates from the central axis of the beam when it just enters the beam, β represents the flight direction of the insect, that is, the angle between the flight direction and O'A, ranging from [0,90) degrees. R is the distance from the insect to the radar, θ is the angle at which the insect deviates from the center of the beam, L is the distance the insect has flown at any time, that is, the distance between the insect and point A, r is the distance from the insect to the central axis of the beam at any time, V h is the horizontal speed of the insect's flight.

[0064] according to Figure 2 , the radar observes vertically to the sky, assuming that the insect flies horizontally at a uniform speed, and the insect enters the beam as the zero moment, then the flight distance of the insect at time t can be expressed as:

[0065] L(t)=V h t

[0066] According to the law of cosines, the distance from the insect to the center of the beam at time t can be expressed as:

[0067]

[0068] The distance R(t) from the insect to the radar at time t can be obtained by radar measurement, so the angle at which the insect deviates from the center of the beam at time t can be expressed as:

[0069]

[0070] Step S2: establishing an amplitude model of the echo signal of the insect passing through the radar beam according to the angle model.

[0071] The target echo amplitude depends on the scattering characteristics of the target and the position of the target in the radar beam, which can be simply expressed as:

[0072] S r =G(θ)·σ

[0073] Where σ is the RCS of the target and G(θ) is the main lobe gain of the radar beam, which can usually be approximated by a Gaussian function:

[0074]

[0075] Where G0 is the gain on the central axis of the beam; k = 8ln2 is a constant; θ 1 / 2 is the half-power beam width; θ is the angle between the beam center axis and the line from the target to the beam center.

[0076] Combined with the angle model, the amplitude of the insect's echo signal at time t can be expressed as:

[0077]

[0078] Among them, S r (t) is the echo signal amplitude of the insect at time t, G0 is the gain on the central axis of the beam, k is a constant, θ 1 / 2 is the half-power beamwidth, and σ is the radar scattering cross-section of the insect.

[0079] Step S3, substituting the time series of insect flight measured by radar into the echo signal amplitude model to generate an ideal echo amplitude sequence.

[0080] According to the echo signal amplitude model, an ideal echo amplitude sequence u=[u1 u2 ... u N-1 ]. u1, u2, u N-1 They represent the echo amplitudes corresponding to the 1st, 2nd, and N-1st moments respectively.

[0081] Step S4, establishing an optimization function based on the ideal echo amplitude sequence and the echo amplitude sequence actually measured by the radar and taking the echo amplitude shape as a constraint.

[0082] The actual radar echo amplitude sequence measured is recorded as w = [w1 w2 ... w N-1 ], the ratio sequence of the ideal echo amplitude sequence and the echo amplitude sequence actually measured by the radar is S d =[u1 / w1 u2 / w2 ... u N-1 / w N-1 ]. At the expense of the echo amplitude shape, an optimization function can be established:

[0083]

[0084] in, is the estimated value of the distance r0 that the insect deviates from the central axis of the beam when it first enters the beam, is the estimated value of the insect's flight direction β, std() is the standard deviation, S d is a ratio sequence.

[0085] Step S5, using a genetic algorithm to solve the above optimization function, to determine the distance and flight direction of the insect from the central axis of the beam when it just enters the beam.

[0086] Optimizing the function is a typical optimization problem that can be solved by genetic algorithm. Genetic algorithm is a mature global optimization algorithm suitable for solving the equation. It should be noted that in the calculation, the equation needs to be solved twice.

[0087] The first solution can get the estimated result of r0cosβ Figure 4 The distribution comparison of the estimated value and the true value of r0cosβ is given after 1000 simulations. Figure 5 The relative error distribution of the estimated value of r0cosβ under 1000 simulations is given. The relative error calculation method is:

[0088]

[0089] Among them, M is the true value of the variable, is the estimated value of the variable. It can be seen that the estimation accuracy of r0cosβ is very high, and the error is almost 0.

[0090] The second solution is based on the value of r0cosβ Solving the equation again as a new condition can give the final estimated results of r0 and β. Substituting the final estimated results into the equation can give the angle sequence θ(t) of the target deviating from the center of the beam during its passage through the beam. Figure 6 Given the estimated error distribution of θ, Figure 7 The average relative error distribution of θ under 1000 simulations is given, and the average relative error calculation method is:

[0091]

[0092] Among them, M i is the i-th sample value, is the estimated value of the ith sample, and N is the number of samples. It can be seen that the angle estimation error is close to 0 degrees. In 1000 simulations, nearly 80% of the simulated angles have an average relative error of less than 10%, and some errors exceed 20%.

[0093] Step S6, based on the time sequence of the insect's flight measured by the radar and the distance and flight direction of the insect's deviation from the center axis of the beam when it just enters the beam, use the angle model to obtain the angle sequence of the insect's deviation from the center of the beam during its passage through the beam, thereby determining the position of the insect in the beam.

[0094] This method is applicable to all radars with pencil beams and can estimate the target position from the echo amplitude shape.

[0095] The present invention first constructs an echo signal amplitude model of an insect crossing a radar beam, generates an ideal echo amplitude sequence, and then combines the measured echo amplitude sequence, takes the echo amplitude shape as a constraint, establishes an optimization function, directly solves the distance from the insect to the central axis of the beam and the flight direction when the insect enters the beam, and finally solves the position of the insect in the beam. The present invention can estimate the target position from the echo amplitude change trend when the radar has no angle measurement function, and is used to solve the problem that the radar cross-sectional area (RCS) measurement is too small when the insect deviates from the center of the radar beam, thereby improving the accuracy of the inversion of the insect body shape parameters, which is helpful to improve the accuracy of the identification of migratory insect species and predict the outbreak of pests and diseases.

[0096] The embodiment of the present invention further provides an insect radar beam in-beam angle measurement system based on target echo amplitude modulation, comprising:

[0097] An angle model building module, used to build an angle model of the insect's deviation from the center of the beam; the angle model is a function of the angle of the insect's deviation from the center axis of the beam and the distance, flight direction and time of the insect's deviation from the center axis of the beam when the insect just enters the beam;

[0098] An amplitude model building module is used to build an amplitude model of the echo signal of the insect passing through the radar beam according to the angle model;

[0099] An amplitude sequence generation module is used to substitute the time sequence of insect flight measured by radar into the echo signal amplitude model to generate an ideal echo amplitude sequence;

[0100] An optimization function establishment module is used to establish an optimization function based on the ideal echo amplitude sequence and the echo amplitude sequence actually measured by the radar, taking the echo amplitude shape as a constraint;

[0101] A flight direction determination module, used to solve the optimization function using a genetic algorithm to determine the distance and flight direction of the insect from the central axis of the beam when it just enters the beam;

[0102] The position determination module is used to obtain the angle sequence of the insect's deviation from the center of the beam when it crosses the beam based on the time sequence of the insect's flight measured by the radar and the distance and flight direction of the insect's deviation from the center axis of the beam when it just enters the beam, and use the angle model to determine the position of the insect in the beam.

[0103] The angle model of the insect's deviation from the beam center is:

[0104]

[0105] Among them, θ(t) is the angle of the insect's deviation from the beam center at time t, r(t) is the distance from the insect to the beam center axis at time t, and R(t) is the distance from the insect to the radar at time t;

[0106] Where r0 is the distance the insect deviates from the center axis of the beam when it first enters the beam, L(t) is the flight distance of the insect at time t, and L(t) = V h t,V h is the horizontal speed of the insect’s flight, and β is the flight direction of the insect.

[0107] The amplitude model of the echo signal when an insect passes through the radar beam is:

[0108]

[0109] Among them, S r (t) is the echo signal amplitude of the insect at time t, G0 is the gain on the central axis of the beam, k is a constant, θ 1 / 2 is the half-power beamwidth, and σ is the radar scattering cross-section of the insect.

[0110] Optimize the function establishment module, including:

[0111] A ratio sequence determination submodule, used to determine a ratio sequence between the ideal echo amplitude sequence and the echo amplitude sequence actually measured by the radar;

[0112] The optimization function establishment submodule is used to establish the optimization function according to the ratio sequence and the echo amplitude shape as a constraint: in, is the estimated value of the distance r0 that the insect deviates from the central axis of the beam when it first enters the beam, is the estimated value of the insect's flight direction β, std() is the standard deviation, S d is a ratio sequence.

[0113] The flight direction determination module includes:

[0114] A primary solution submodule, used to solve the optimization function once using a genetic algorithm to obtain the optimal solution of r0cosβ;

[0115] The secondary solution submodule is used to combine the optimal solution of r0cosβ and use a genetic algorithm to perform a secondary solution on the optimization function to obtain the optimal solution of the distance r0 that the insect deviates from the central axis of the beam when it just enters the beam and the optimal solution of the flight direction β.

[0116] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0117] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for measuring angles within an insect radar beam based on target echo amplitude modulation, characterized in that: include: Model the angle at which the insect deviates from the center of the beam; The angle model is a function of the angle at which the insect deviates from the central axis of the beam, the distance at which the insect deviates from the central axis of the beam when it first enters the beam, the flight direction, and the time; According to the angle model, an amplitude model of the echo signal of the insect passing through the radar beam is established; Substituting the time series of insect flight measured by radar into the echo signal amplitude model to generate an ideal echo amplitude series; According to the ideal echo amplitude sequence and the echo amplitude sequence actually measured by the radar, an optimization function is established with the echo amplitude shape as a constraint; A genetic algorithm is used to solve the optimization function to determine the distance and flight direction of the insect from the central axis of the beam when the insect just enters the beam; According to the time sequence of the insect's flight measured by radar and the distance and flight direction of the insect's deviation from the beam center axis when it just enters the beam, the angle model is used to obtain the angle sequence of the insect's deviation from the beam center during its crossing of the beam, thereby determining the insect's position in the beam.

2. The method for measuring angle within an insect radar beam based on target echo amplitude modulation according to claim 1, characterized in that: The angle model of the insect deviating from the beam center is: Among them, θ(t) is the angle of the insect's deviation from the beam center at time t, r(t) is the distance from the insect to the beam center axis at time t, and R(t) is the distance from the insect to the radar at time t; Where r0 is the distance the insect deviates from the center axis of the beam when it first enters the beam, L(t) is the flight distance of the insect at time t, and L(t) = V h t,V h is the horizontal speed of the insect’s flight, and β is the flight direction of the insect.

3. The method for measuring angle within an insect radar beam based on target echo amplitude modulation according to claim 2, characterized in that: The amplitude model of the echo signal of the insect passing through the radar beam is: Among them, S r (t) is the echo signal amplitude of the insect at time t, G0 is the gain on the central axis of the beam, k is a constant, θ 1 / 2 is the half-power beamwidth, and σ is the radar scattering cross-section of the insect.

4. The method for measuring angles within an insect radar beam based on target echo amplitude modulation according to claim 2, characterized in that: According to the ideal echo amplitude sequence and the echo amplitude sequence actually measured by the radar, an optimization function is established with the echo amplitude shape as a constraint, specifically including: Determine a ratio sequence of the ideal echo amplitude sequence and the echo amplitude sequence actually measured by the radar; According to the ratio sequence, taking the echo amplitude shape as a constraint, the optimization function is established as in, is the estimated value of the distance r0 that the insect deviates from the central axis of the beam when it first enters the beam, is the estimated value of the insect's flight direction β, std() is the standard deviation, S d is a ratio sequence.

5. The method for measuring angles within an insect radar beam based on target echo amplitude modulation according to claim 4, characterized in that: The method of using a genetic algorithm to solve the optimization function and determine the distance and flight direction of the insect from the central axis of the beam when it just enters the beam specifically includes: A genetic algorithm is used to solve the optimization function once to obtain the optimal solution of r0cosβ; Combined with the optimal solution of r0cosβ, a genetic algorithm is used to perform a secondary solution on the optimization function to obtain the optimal solution of the distance r0 that the insect deviates from the central axis of the beam when it just enters the beam and the optimal solution of the flight direction β.

6. An insect radar beam angle measurement system based on target echo amplitude modulation, characterized in that: include: An angle model building module, used to build an angle model of the insect's deviation from the beam center; The angle model is a function of the angle at which the insect deviates from the central axis of the beam, the distance at which the insect deviates from the central axis of the beam when it first enters the beam, the flight direction, and the time; An amplitude model building module is used to build an amplitude model of the echo signal of the insect passing through the radar beam according to the angle model; An amplitude sequence generation module is used to substitute the time sequence of insect flight measured by radar into the echo signal amplitude model to generate an ideal echo amplitude sequence; An optimization function establishment module is used to establish an optimization function based on the ideal echo amplitude sequence and the echo amplitude sequence actually measured by the radar, taking the echo amplitude shape as a constraint; A flight direction determination module, used to solve the optimization function using a genetic algorithm to determine the distance and flight direction of the insect from the central axis of the beam when it just enters the beam; The position determination module is used to obtain the angle sequence of the insect's deviation from the center of the beam when it crosses the beam based on the time sequence of the insect's flight measured by the radar and the distance and flight direction of the insect's deviation from the center axis of the beam when it just enters the beam, and use the angle model to determine the position of the insect in the beam.

7. The insect radar beam angle measurement system based on target echo amplitude modulation according to claim 6 is characterized in that: The angle model of the insect deviating from the beam center is: Among them, θ(t) is the angle of the insect's deviation from the beam center at time t, r(t) is the distance from the insect to the beam center axis at time t, and R(t) is the distance from the insect to the radar at time t; Where r0 is the distance the insect deviates from the center axis of the beam when it first enters the beam, L(t) is the flight distance of the insect at time t, and L(t) = V h t,V h is the horizontal speed of the insect’s flight, and β is the flight direction of the insect.

8. The insect radar beam angle measurement system based on target echo amplitude modulation according to claim 7, characterized in that: The amplitude model of the echo signal of the insect passing through the radar beam is: Among them, S r (t) is the echo signal amplitude of the insect at time t, G0 is the gain on the central axis of the beam, k is a constant, θ 1 / 2 is the half-power beamwidth, and σ is the radar scattering cross-section of the insect.

9. The insect radar beam angle measurement system based on target echo amplitude modulation according to claim 7, characterized in that: The optimization function establishment module specifically includes: A ratio sequence determination submodule, used to determine a ratio sequence between the ideal echo amplitude sequence and the echo amplitude sequence actually measured by the radar; The optimization function establishment submodule is used to establish the optimization function according to the ratio sequence and the echo amplitude shape as a constraint: in, is the estimated value of the distance r0 that the insect deviates from the central axis of the beam when it first enters the beam, is the estimated value of the insect's flight direction β, std() is the standard deviation, S d is a ratio sequence.

10. The insect radar beam angle measurement system based on target echo amplitude modulation according to claim 9, characterized in that: The flight direction determination module specifically includes: A primary solution submodule, used to solve the optimization function once using a genetic algorithm to obtain the optimal solution of r0cosβ; The secondary solution submodule is used to combine the optimal solution of r0cosβ and use a genetic algorithm to perform a secondary solution on the optimization function to obtain the optimal solution of the distance r0 that the insect deviates from the central axis of the beam when it just enters the beam and the optimal solution of the flight direction β.

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