Statistical Method and Device for Biological Migration Flux of Insect Radar

Abstract

The present invention discloses a method and device for statistically calculating the biological migration flux of insect radar, belonging to the technical field of insect radar, which solves the problem of statistical error caused by the deviation of the position of insect movement from the beam normal line, and helps to improve the accuracy of statistical calculation of insect migration flux. The technical solution of the present invention is as follows: In the vertical measurement mode, a statistical method model for insect migration flux is established, and the statistical unit (k,n) is defined; the actual distance that all insects pass through the beam is obtained; an estimation model of the radar beam and the position where the migrating insects pass through the beam is established, and the deviation parameter is obtained based on the longest distance that the target passes through the beam and the actual distance that the target passes through the beam; the statistical method is used to estimate the insect migration flux, and the flux statistical results of different altitude layers are obtained. According to the expression of the migration flux in the fixed beam mode of vertical measurement and the flux statistical results of different altitude layers, the expression of the migration flux in the fixed beam mode of any direction and the flux statistical results of different altitude layers are obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of insect radar, and particularly relates to a method and device for statistically analyzing the biological migration flux of insects by an insect radar. Background Art

[0002] Migratory entomology is a discipline that studies the insect sources, migration routes, migratory behaviors and their regulation, as well as research methods and means. As a tool for long-distance detection, radar can achieve all-day and all-weather monitoring of the target airspace, providing the most effective means for observing the migration of insect swarms in the air. Its application and development have promoted the development of migratory entomology from qualitative research to quantitative analysis, playing an irreplaceable role in the field of insect migration. As the most important index for insect radar monitoring, the migratory biological flux can provide information on the number of insects migrating per unit volume at different heights in the airspace within the radar detection range over a period of time, that is, the insect migration flux. For migratory biology research, this information can be used to analyze the migration patterns of insects at different altitude layers and their correlation with other meteorological information; for the plant protection department, this information can be used to evaluate the scale and risk level of insect migration to take preventive measures in advance; for biological research, the migration flux can be used to analyze the life cycle law of insects during migration. Therefore, accurately statistically analyzing the flux information of high-altitude migratory insects is of great significance for in-depth research in many disciplines.

[0003] The current algorithm model for migratory flux statistics calculates the volume of the target that can be detected in the RCS segment at this altitude layer based on the RCS of the measurement target. In this method, the accuracy of flux statistics is greatly affected by the measurement accuracy of the target RCS. Especially for an insect radar without the function of measuring the angle inside the beam, it is impossible to estimate the distance between the crossing track of the insect target and the beam center axis, that is, it is impossible to obtain an accurate target RCS value, which will introduce a large flux statistical error. Summary of the Invention

[0004] In view of this, the present invention provides a method and device for statistically analyzing the biological migration flux of insects by an insect radar. An estimation model of the radar beam and the position where the migratory insects cross the beam is established, and statistical methods are used to estimate the insect migration flux, solving the problem of statistical error caused by the deviation of the insect movement from the beam normal position, which helps to improve the accuracy of insect migration flux statistics.

[0005] To achieve the above object, the technical solution of the present invention includes the following steps:

[0006] Step 1, in the vertical measurement mode, establish a model of the method for statistically analyzing the insect migration flux, clarify the statistical height interval k and the statistical time interval n, and define it as the statistical unit (k, n);

[0007] Step 2: Calculate the actual distance X that all insects cross the beam i (k,n);

[0008] Step 3: Establish an estimation model for the position where the radar beam and the migrating insects cross the beam. Based on the longest distance D i (k,n) that the target crosses the beam and the actual distance X i (k,n) to obtain the deviation parameter μ i (k,n);

[0009] Step 4: Use statistical methods to estimate the migration flux of insects. Based on to obtain the flux statistical results of different altitude layers.

[0010] Step 5: According to the expression of the migration flux in the fixed beam mode of vertical measurement and the flux statistical results of different altitude layers, obtain the expression of the migration flux in the fixed beam mode with any pointing and the flux statistical results of different altitude layers.

[0011] Furthermore, Step 1 is specifically as follows:

[0012] First, establish a statistical model for the migration flux of insects in the vertical measurement mode of the radar. In the vertical measurement mode, the radar beam is adjusted vertically to the sky and remains fixed. The detectable range of the radar depends on the radar detection power, beam width, and working waveform.

[0013] First, determine the statistical time length ΔT. ΔT represents a minimum statistical time period, and statistics are performed every ΔT time; the statistical time sequence is denoted as (T1, T2, T3, … T n …).

[0014] Divide the detection beam of the radar into several equal altitude layers according to altitude, and the height of each layer is Δh.

[0015] Denote the middle height of each altitude layer as (h1, h2, h3, … h k …); h k is the middle height of the kth altitude layer.

[0016] H min and H max represent the lowest detection height and the highest detection height of the radar, and R min and R max represent the minimum detection distance and the maximum detection distance of the radar; in the vertical measurement mode, H min = R min , H max = R max .

[0017] Within the ΔT time interval at time T n and altitude layer hk The number of insects detected by the radar is num k,n , and the RCSs of the 1st to the num k,n th insects are respectively The distances from the insects to the radar are respectively It is assumed that each insect horizontally crosses the radar beam and can pass through the beam center; the horizontal distance within the beam where the echo power is above the detection threshold is D i (k,n), which is the longest distance of crossing the beam

[0018] Among them, the migration flux is the total number of all insects crossing a unit area per unit time

[0019] Assume that at time T n Time interval ΔT n , height h k At height interval Δh k , that is, within the defined minimum statistical unit (k,n), if the radar detects an insect, then within this statistical unit, the calculation method of the migration flux flux′(k,n) is as follows:

[0020]

[0021] Among them, Δh k is the height interval of the kth statistical unit of the self-defined statistical variable, and ΔT n is the time interval of the nth statistical unit;

[0022] If num k,n migratory insects are detected within the minimum statistical unit (k,n), the formula for the flux statistics flux(k,n) is:

[0023]

[0024] When the insect radar is actually applied, the average of the flux statistics flux(k,n) is calculated over n time periods, and the flux statistics results Flux(k) of different height layers within N time statistical units are calculated. The formula is:

[0025]

[0026] Furthermore, in step two, find the actual crossing beam distances X i (k,n) of all insects; specifically:

[0027] Define that at a distance r i , the actual horizontal flying distance of the insect being measured is X i (k,n), named the actual crossing beam distance; the calculation formula of X i (k,n) is:

[0028]

[0029] where SNR min is the minimum detection threshold, and the coefficient C is determined by the hardware of the insect radar. R i (k, n) is the distance of the i-th insect measured by the radar; θ 3db is the 3 dB width of the half-power beam of the radar; δ i (k, n) is the RCS of the insect being measured.

[0030] Furthermore, in step three, the deviation parameter μ i (k, n) is the ratio of X i (k, n) to D i (k, n), named the deviation coefficient:

[0031]

[0032] Furthermore, the deviation coefficient μ i (k, n) of the i-th insect has a derivation result of:

[0033]

[0034] Furthermore, in step five, the expression of the migration flux in the vertical measurement fixed beam mode is:

[0035]

[0036] The expression of the migration flux in the fixed beam mode with an arbitrary pointing is:

[0037]

[0038] Over a period of time, the calculation formula for the flux statistics at all altitudes is the same as that in the vertical measurement mode;

[0039] The flux statistics results for different altitude layers:

[0040]

[0041] Furthermore, when the insect radar beam points to an arbitrary pitch angle α and is fixed, within the statistical unit (k, n) interval, the migration flux is:

[0042]

[0043] Another embodiment of the present invention also provides an insect radar biological migration flux statistical device, which is characterized by including a data acquisition module, a statistical method model module, an actual crossing beam distance solving module, a deviation parameter estimation module, and a migration flux estimation module.

[0044] A data acquisition module, which is used to obtain data on the statistical insect migration flux from an insect radar.

[0045] A statistical method model module, which is used to construct a statistical method model for the insect migration flux in the vertical measurement mode, clarify the statistical height interval k and the statistical time interval n, and define it as the statistical unit (k,n).

[0046] An actual crossing beam distance solving module, which is used to calculate the actual crossing beam distance X of all insects i (k,n).

[0047] A deviation parameter estimation module, which is used to establish an estimation model for the position of the radar beam and the crossing beam of migrating insects, based on the longest crossing beam distance D of the target i (k,n) and the actual crossing beam distance X i (k,n) to obtain the deviation parameter μ i (k,n).

[0048] A migration flux estimation module, which is used to estimate the insect migration flux using statistical methods, based on to obtain the flux statistical results of different height layers.

[0049] For this insect radar biological migration flux statistical device, the data acquisition module is used to obtain data on the statistical insect migration flux from the insect radar, including the following data:

[0050] The statistical time length ΔT, where ΔT represents a minimum statistical time period, and statistics are performed every ΔT time; the statistical time sequence is denoted as (T1,T2,T3,…T n …);

[0051] The detection beam of the radar is divided into several equal-height layers according to height, and the height of each layer is Δh.

[0052] The middle height of each height layer is (h1,h2,h3,…h k …); h k is the middle height of the kth height layer.

[0053] The lowest detection height and the highest detection height H of the radar min and H max , the minimum detection distance and the maximum detection distance R of the radar min and R max .

[0054] Within the ΔT time interval at time T n , the number of insects detected by the radar at height layer h k is num k,n , and it is set that the RCS of the 1st to the num k,n th insects are respectively The distances from the insects to the radar are respectively

[0055] It is assumed that each insect horizontally crosses the radar beam and can cross the beam center; the horizontal distance within the beam where the echo power is above the detection threshold is D i (k, n), which is the longest distance of crossing the beam

[0056] Furthermore, for the actual beam-crossing distance solving module, at a distance r i the actual measured horizontal flight distance of the insect is X i (k, n), named the actual beam-crossing distance; X i (k, n) is calculated by the formula:

[0057]

[0058] In the formula, SNR min is the minimum detection threshold, the coefficient C is determined by the insect radar hardware, R i (k, n) is the distance of the i-th insect measured by the radar; θ 3db is the 3dB width of the half-power beam of the radar; δ i (k, n) is the RCS of the insect measured

[0059] For the deviation parameter estimation module, the deviation parameter u i (k, n) is the ratio of X i (k, n) to D i (k, n), named the deviation coefficient:

[0060]

[0061] For the migration flux estimation module, when the insect radar beam points to an arbitrary pitch angle α and is fixed, within the statistical unit (k, n) interval, the migration flux is:

[0062]

[0063] Beneficial effects:

[0064] 1. The present invention discloses a method for statistically analyzing the biological migration flux of an insect radar based on angle measurement inside the beam, providing an effective means for accurately counting the number of migrating insects per unit volume at different heights. This method first constructs a model for the statistical method of insect migration flux, then solves the actual beam-crossing distances of all insects, establishes an estimation model for the positions of the radar beam and the migrating insects crossing the beam, and uses statistical methods to estimate the insect migration flux, eliminating the statistical error caused by the deviation angle between the insect crossing the beam and the beam normal, and improving the accuracy of the statistical analysis of the insect migration flux.

[0065] 2. The method for statistically analyzing the biological migration flux of insect radar provided by the present invention improves the existing statistical model of insect radar flux, establishes an estimation model for the position where the radar beam intersects with the migrating insects passing through the beam, and uses this model to estimate the actual distance that all migrating insects pass through the beam, with more accurate results.

[0066] 3. The method for statistically analyzing the biological migration flux of insect radar provided by the present invention is based on the longest target crossing beam distance D i (k,n) and the actual crossing beam distance X i (k,n) to obtain a deviation parameter, which reflects the flux statistical error caused by the randomness of migrating insects passing through the beam, providing a data basis for obtaining more accurate statistical results of insect migration flux subsequently.

[0067] 4. The method for statistically analyzing the biological migration flux of insect radar provided by the present invention obtains the expression of the migration flux in the fixed beam mode with an arbitrary pointing and the statistical results of the flux at different altitude layers according to the expression of the migration flux in the fixed beam mode with vertical measurement and the statistical results of the flux at different altitude layers. That is, the present invention is applicable to both the fixed beam with vertical measurement and the fixed beam with an arbitrary pointing, significantly improving the universality of the migration flux statistics, and is of great significance for the assessment of the scale of insect migration and the early warning of agricultural pests.

[0068] 5. The device for statistically analyzing the biological migration flux of insect radar provided by the present invention includes a data acquisition module, a statistical method model module, an actual crossing beam distance solving module, a deviation parameter estimation module, and a migration flux estimation module. The functions of each module are set. The data acquisition module is set to receive and process data to provide data support for subsequent modules. The statistical method model module improves the existing statistical model of insect radar flux. The actual crossing beam distance solving module establishes an estimation model for the position where the radar beam intersects with the migrating insects passing through the beam. The deviation parameter estimation module estimates the deviation parameter, and the migration flux estimation module is used to estimate the migration flux, enabling accurate and efficient statistics of the number of migrating insects per unit volume at different altitudes.

[0069] 6. The device for statistically analyzing the biological migration flux of insect radar provided by the present invention improves the existing statistical model of insect radar flux, establishes an estimation model for the position where the radar beam intersects with the migrating insects passing through the beam, and uses this model to estimate the actual distance that all migrating insects pass through the beam, with more accurate results. Based on the longest target crossing beam distance D i (k,n) and the actual crossing beam distance X i (k,n) to obtain a deviation parameter, which reflects the flux statistical error caused by the randomness of migrating insects passing through the beam, providing a data basis for obtaining more accurate statistical results of insect migration flux subsequently. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 It is a statistical model diagram of the migratory flux of fixed beam vertical measurement for the present invention;

[0071] Figure 2 It is a schematic diagram of the deviation angle between the insect flight path and the beam center for the present invention;

[0072] Figure 3 It is a schematic diagram of flux statistics under the stationary beam in the general case of the present invention.

[0073] Figure 4 The simulation input conditions of the present invention are (a) insect RCS distribution, (b) insect height distribution, (c) insect speed distribution, (d) crossing distance X i Distribution

[0074] Figure 5 It is a flow chart of the statistical method for the biological migratory flux of insect radar provided by the present invention;

[0075] Figure 6 It is a block diagram of the device for the statistical method of the biological migratory flux of insect radar provided by the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0076] The present invention will be described in detail below with reference to the accompanying drawings and by way of examples.

[0077] The present invention provides a statistical method model for the migratory flux of insects, and discusses the applicability of the model in the vertical measurement fixed beam and the arbitrary pointing fixed beam modes respectively.

[0078] Step 1: In the vertical measurement mode, establish a statistical method model for the migratory flux of insects. Specifically:

[0079] First, establish a migratory flux statistical model for the radar in the vertical measurement mode. In this mode, the radar beam is adjusted vertically to the sky and remains fixed. In this mode, the detectable range of the radar depends on the radar detection power, beam width and working waveform. In this working mode, the schematic diagram is as Figure 1 shown.

[0080] First, determine the statistical time length ΔT. ΔT represents a minimum statistical time period, and statistics are performed every ΔT time. The statistical time sequence is denoted as (T1, T2, T3,... T n ...). Divide the detection beam of the radar into several equal height layers according to height, and the height of each layer is Δh. Denote the middle height of each height layer as (h1, h2, h3,... h k ...). H min and H max represent the lowest detection height and the highest detection height of the radar, respectively. R min and Rmax represent the minimum and maximum detection distances of the radar. In the vertical measurement mode, H min = R min , H max = R max .

[0081] Assume that within the time interval ΔT at time T n , the number of insects detected by the radar at altitude layer h k is num k,n , and assume that the RCSs of these insects are respectively The distances of the insects from the radar are respectively Assume that each insect horizontally crosses the radar beam and can cross the beam center. The horizontal distance of its echo power above the detection threshold within the beam is D i (k,n), named the longest beam-crossing distance. Define the migration flux as the total number of all insects crossing a unit area per unit time.

[0082] Assume that at time T n time interval ΔT n , at altitude h k with altitude interval Δh k , that is, within the defined minimum statistical unit (k,n), if the radar detects an insect, then within this statistical unit, the calculation method of the migration flux flux′(k,n) is as shown in Equation (1):

[0083]

[0084] If num k,n migratory insects are detected within the minimum statistical unit (k,n), the flux statistic flux(k,n) is the sum of Equation (1), and the calculation formula is as follows:

[0085]

[0086] Equation (2) is the calculation method of the migration flux flux(k,n) within the statistical unit (k,n). In actual application of the insect radar, it is often necessary to statistically analyze the flux statistics results at different altitude layers over a relatively long period of time (N time statistical units). The average value of Equation (2) can be calculated over n time periods, and the calculation formula is:

[0087]

[0088] Step 2, find the actual beam-crossing distances X i (k,n) of all insects, specifically:

[0089] Define that at distance r i the actual horizontal flight distance of the insect being measured is Xi (k,n), named as the actual crossing beam distance.

[0090] First, calculate the detectable level flight distance X for the target to cross the beam through the measured RCS of the target. i (k,n), (0 < i ≤ num k,n ). In the (n,k) statistical unit, there are num k,n head insects passing through the beam in sequence with the number i. Generally, when an insect crosses the radar beam, it crosses the radar beam in a straight line. It is known that for any insect, when flying over the radar beam, as Figure 2 shown, the radar will output L discrete measurement points A l , where (0 < l ≤ L), forming a set of target reflection signals that become stronger first and then weaker. The target echo power reaches the strongest point at A i , and the distance R between the target and the radar at point A i . i . Let be the beam normal direction, then The angle between and point is defined as γ i , and the angle between the line connecting the radar and each discrete detection point and is defined as θ l . For a certain detected insect, θ l can reach up to θ max .

[0091] Use the target RCS of the insect at point A to calculate the actual crossing beam distance X i (k,n). Assume that the radar pattern is Gaussian-shaped, and define the radar half-power beam width as θ 3dB , then the approximate formula for the pattern is:

[0092]

[0093] On the direction of the insect crossing path A l , the maximum detectable angle θ max can be approximately solved as:

[0094]

[0095] where R max-i is the maximum detectable distance of the radar for this insect in the direction of the angle with γ i . On the direction of the crossing path A l , the calculation method of X i (k,n) is:

[0096] X i (k,n) ≈ 2R i(k,n)·θ max-i (k,n) (6)

[0097] According to Equations (4)–(6), X can be obtained i Calculation formula of (k,n):

[0098]

[0099] In the formula, SNR min is the minimum detection threshold, and the coefficient C is determined by the hardware of the insect radar.

[0100] Step 3: Establish an estimation model for the radar beam and the position where the migratory insects cross the beam. Based on the longest cross-beam distance D of the target i (k,n) and the actual cross-beam distance X i (k,n), the deviation parameter μ is obtained, specifically as follows:

[0101] Equations (2) and (3) are the statistical calculation methods for the insect migration flux under ideal conditions, where Δh k and ΔT n are known statistical condition parameters. To obtain the flux statistical result, it is necessary to know the longest cross-beam distance D i (k,n) of all detected targets. According to the introduction by Chapman J W et al in the article, D i (k,n) is determined by the magnitude of the RCS value measured by the target. In the actual migration scenario, the probability of an insect crossing the beam center is extremely small. Since the RCS measurement is based on the assumption that the insect crosses the beam center, the measured value of the target RCS will be smaller than the true RCS σ i on the small side.

[0102] Suppose an insect crosses the beam three times from different positions, forming three target tracks A, B, and C in the figure. Among these three tracks, track B is closest to the beam center, and the echo power received by the insect radar is the strongest. Therefore, the measured target RCS is relatively large; track A is the second; track C is the farthest from the beam center, so the measured target RCS is relatively the smallest. Due to the randomness of the position where the insect crosses the beam and the lack of the ability of the insect radar to measure the angle inside the beam, the RCS of the insect measured by the insect radar usually obtains a value smaller than the true value. Therefore, the longest cross-beam distance D i (k,n) of the target measured by the insect radar is on the small side, and the statistically calculated flux is on the small side.

[0103] To solve the problem of large flux statistical errors caused by the randomness of the position where migratory insects cross the beam, this paper proposes a flux statistical method based on a statistical method to calculate the longest cross-beam distance D i (k,n) of all targets within the statistical unit. Define the random variable μ as Xi (k, n) and D i The ratio of (k, n) to D is named the deviation coefficient:

[0104]

[0105] According to Equation (1), since Δh k and ΔT n are constants, the expectation of flux′(k, n) is:

[0106]

[0107] Step 4: Estimate the insect migration flux using statistical methods. Based on the assumption obtain the flux statistical results for different altitude layers, specifically:

[0108] In Equation (8), when μ i (k, n) = 1 (i.e., the insect crosses the beam center), the obtained flux is the accurate value. According to the previous discussion, in most cases, μ i (k, n) < 1, X i (k, n) < D i (k, n). However, the value of μ i (k, n) cannot be measured. In actual calculations, the traditional method assumes that the target crosses the beam center, i.e., μ i (k, n) = 1, which results in an overestimated measured flux. To solve the problem that μ i (k, n) cannot be obtained by measurement, the following assumptions are made in this paper:

[0109]

[0110] Substituting Equation (10) into Equation (9) gives:

[0111]

[0112] According to Equation (2), within the minimum statistical unit (k, n), the flux statistic flux(k, n) of the detected num k,n migrating insects is:

[0113]

[0114] In Equation (12), Δh k and ΔT n are the k-th custom statistical variables, E[X i (k, n)] and num k,n are indirectly obtained during the radar calculation and monitoring process. Next, calculate the expectation E[μ i(k,n)]. Define that within this statistical unit, when an insect with a certain determined RCS passes through the beam, the distance from the center of the radar beam is Y i (k,n). Since the positions of the targets in the air are uniformly distributed, the random variable Y i (k,n) follows a uniform distribution. From the trigonometric function relationship, we can obtain:

[0115]

[0116] Divide both sides of Equation (13) by D i (k,n) take the mean value:

[0117]

[0118] That is:

[0119]

[0120] For the right side of Equation (15), is a function of, so according to the definition of the probability distribution function, we can obtain:

[0121]

[0122] That is, E[μ i (k,n)] = 0.7854. Substitute it into Equation (12) to obtain:

[0123]

[0124] Substitute Equation (17) into Equation (3), and we can calculate the flux statistical results of different altitude layers by the insect radar over a relatively long period of time (N time statistical units):

[0125]

[0126] Step Five: According to the expression of the migratory flux in the fixed beam mode of vertical measurement and the flux statistical results of different altitude layers, obtain the expression of the migratory flux in the fixed beam mode with an arbitrary pointing and the flux statistical results of different altitude layers. Specifically:

[0127] For the establishment of the migratory insect flux statistical model, for a more general situation, the insect radar not only needs to measure the migratory situation directly above, but also needs to adjust the beam pointing of the radar through the servo of the radar, so as to broaden the monitoring range and cover the entire airspace with the beam. This step gives the method for statistical analysis of the aerial biological migratory flux when the insect radar is at a certain elevation angle and the beam is in a stationary state.

[0128] From Figure 3It can be seen that when the insect radar detects the air with a stationary beam at an elevation angle α less than 90°, the detection height range changes with the beam elevation angle. The statistical height and the detection range of the insect radar can be converted through a simple trigonometric function relationship. H min = R min sinα, H max = R max sinα. To simplify the calculation, the area unit perpendicular to the radar beam normal is still taken as the minimum statistical area unit, as shown in Figure 3 . After determining the statistical height interval Δh, the actual height of the area unit for counting insects crossing the statistics is Δh / sinα. Similar to the vertical measurement mode, the height at the center of the distance segment is taken as the height of this statistical unit.

[0129] Therefore, substituting Δh / sinα for Δh into Equation (17), when the insect radar operates in the fixed beam mode at any elevation angle α, within the statistical time ΔT n and the statistical height Δh k , the expression for the migration flux is:

[0130]

[0131] For a relatively long time period, the calculation formula for the flux statistics at all heights is the same as that in the vertical measurement mode, the same as Equation (18).

[0132] In the present invention, when the radar is in the vertical measurement working mode, one hundred thousand migratory insects randomly cross the radar beam within 12 hours. The actual migration flux statistical results are compared with the calculation results of the statistical model designed in the second section, so as to verify the correctness and confidence range of the statistical model.

[0133] Assume that the RCS σ of 10 5 migratory insects follows a normal distribution with a mean E = -40 and a standard deviation σ = 10, in units of dBsm, as shown in i (a) in; the migration height H Figure 4 follows a normal distribution with a mean E = 500 and a standard deviation σ = 50, in units of meters, as shown in i (b) in; the time t Figure 4 when entering the radar beam occurs randomly within 12 hours; the migration speed vi follows a normal distribution with a mean E = 15 and a standard deviation σ = 5, in units of meters per second, as shown in i (c) in; and assume that the distance Y Figure 4 of each insect from the center of the radar beam i , follows a random uniform distribution, corresponding to solving the deviation coefficient μ i , and the actual crossing distance X of the insect i, and its distribution is as shown in (d) of Figure (4).

[0134] According to the above conditions, the migration flux statistics are performed every 1 minute for 12 hours, that is, ΔT = 60 s, and the height is statistically analyzed every 1 m interval, that is, Δh = 1 m, to calculate the obtained migration flux statistics results. Since the deviation coefficient μ is known i , therefore, according to the assumed simulation conditions X i the longest beam-crossing distance D of each insect can be obtained respectively i . Using D i the theoretical migration flux statistics results can be further calculated. The calculation method is within the statistical unit (k,n), according to the definition formula (2) of the migration flux, the flux statistics results with a height interval of Δh = 1 m and a time interval of ΔT = 60 s are obtained, and then according to the definition formula (3), the flux statistics height-flux profile with the same height interval of Δh = 1 m within 12 hours is obtained. This result is the flux statistics result of the theoretically occurring migration.

[0135] If the migration flux statistical model proposed by the present invention is used to make reasonable assumptions about the actual beam-crossing distance X i (k,n) of each insect in the statistical unit (k,n), according to formula (13), the flux statistics results under the conditions of a height interval of Δh = 1 m and a time interval of ΔT = 60 s are obtained, and then according to formula (14), the flux statistics height-flux profile within 12 hours with the same height interval of Δh = 1 m is obtained. This result is the statistical result of the migration flux calculated by the migration flux statistical method designed in this paper for the random beam-crossing of insects in the vertical measurement mode of the insect radar.

[0136] The flow of the migration flux method provided by the present invention is as Figure 5 shown.

[0137] Another embodiment of the present invention also provides an insect radar biological migration flux statistical device, as Figure 6 shown.

[0138] The insect radar biological migration flux statistical device includes a data acquisition module, a statistical method model module, an actual beam-crossing distance solving module, a deviation parameter estimation module, and a migration flux estimation module;

[0139] The data acquisition module is used to obtain data on the migration flux of insects by the insect radar.

[0140] The statistical method model module is used to construct a statistical method model for the migration flux of insects in the vertical measurement mode, clarify the statistical height interval k and the statistical time interval n, and define it as the statistical unit (k,n).

[0141] The actual beam-crossing distance solving module is used to calculate the actual beam-crossing distance X of all insects i (k,n).

[0142] The deviation parameter estimation module is used to establish an estimation model for the position of the radar beam and the migratory insects crossing the beam, based on the longest beam-crossing distance D i (k,n) and the actual beam-crossing distance X i (k,n) to obtain the deviation parameter u i (k,n).

[0143] The migratory flux estimation module is used to estimate the migratory flux of insects using statistical methods, based on to obtain the flux statistical results for different altitude layers.

[0144] Among them, the data acquisition module is used to obtain the data of the insect radar for statistically analyzing the migratory flux of insects, including the following data:

[0145] The statistical time length ΔT, where ΔT represents a minimum statistical time period, and statistics are performed every ΔT time; the statistical time series is denoted as (T1, T2, T3, … T n …).

[0146] The detection beam of the radar is divided into several equal altitude layers according to altitude, and the altitude of each layer is Δh.

[0147] The middle altitude of each altitude layer is (h1, h2, h3, … h k …); h k is the middle altitude of the kth altitude layer.

[0148] The lowest detection altitude and the highest detection altitude H of the radar min and H max , the minimum detection distance and the maximum detection distance R of the radar min and R max .

[0149] Within the ΔT time interval at time T n , the number of insects detected by the radar at altitude layer h k is num k,n , and it is set that the RCS of the 1st to the num k,n th insects are respectively The distances of the insects to the radar are respectively

[0150] It is set that each insect horizontally crosses the radar beam and can cross the beam center; the horizontal distance of its echo power above the detection threshold within the beam is D i (k,n), which is the longest beam-crossing distance.

[0151] Among them, the actual crossing beam distance solving module is defined at a distance r i where the actual horizontal flight distance of the insect being measured is X i (k,n), named the actual crossing beam distance; X i (k,n) is calculated as follows:

[0152]

[0153] In the formula, SNR min is the minimum detection threshold, the coefficient C is determined by the insect radar hardware, and R i (k,n) is the distance measured by the radar for the i-th insect; θ 3db is the 3dB width of the half-power beam of the radar; δ i (k,n) is the RCS of the insect being measured.

[0154] Deviation parameter estimation module, the deviation parameter u i (k,n) is the ratio of X i (k,n) to D i (k,n), named the deviation coefficient:

[0155]

[0156] Migration flux estimation module, when the insect radar beam points to any pitch angle α and is fixed, within the statistical unit (k,n) interval, the migration flux is:

[0157]

[0158] In summary, the above is only the preferred embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Statistical method for biological migration flux of insect radar, characterized in that Including: Step 1: In the vertical measurement mode, establish a statistical method model for insect migration flux, clarify the statistical height interval k and statistical time interval n, and define it as the statistical unit (k, n); Step 2, calculate the actual distance X that all insects cross the beam i (k,n); Step 3: Establish an estimation model for the radar beam and the position where the migratory insects cross the beam, based on the horizontal distance D i (k,n) of the longest target crossing beam and the actual crossing beam distance X i (k,n) to obtain the deviation parameter μ i (k,n); Step 4: Estimate the insect migration flux using statistical methods. Based on Obtain the flux statistical results for different altitude layers; Step 5: According to the expression of the migration flux in the vertical measurement fixed beam mode and the flux statistical results of different altitude layers, obtain the expression of the migration flux in any pointing fixed beam mode and the flux statistical results of different altitude layers; The specific content of the said Step 1 is: First, establish a statistical model for insect migration flux by the radar in the vertical measurement mode. In the said vertical measurement mode, the radar beam adjusts vertically to the sky and remains fixed. The detectable range of the radar depends on the radar detection power, beam width, and working waveform; First, determine the statistical time length ΔT. ΔT represents a minimum statistical time period, and statistics are performed every ΔT time; the statistical time series is denoted as (T1, T2, T3, … T n …); Divide the detection beam of the radar into several equal altitude layers according to height, and the height of each layer is Δh; Denote the intermediate height of each altitude layer as (h1, h2, h3, … h k …); h k is the intermediate height of the k-th altitude layer; H min With H max represent the minimum detection altitude and the maximum detection altitude of the radar, R min With R max represent the minimum detection distance and the maximum detection distance of the radar; in the vertical measurement mode, H min = R min and H max = R max ; At time T n within the ΔT time interval, at altitude layer h k the number of insects detected by the radar is num k,n , and the RCSs of the 1st to the num k,n th insects are respectively the distances from the insects to the radar are respectively It is assumed that each insect horizontally crosses the radar beam and can cross the beam center; the horizontal distance within the beam where the echo power is above the detection threshold is D i (k,n), which is the longest distance of crossing the beam; Among them, the migration flux is the total number of all insects passing through a unit area within a unit time; Assume at time T n Time interval ΔT n and height h k with height interval Δh k That is, within the defined minimum statistical unit (k, n), if the radar detects an insect, then within this statistical unit, the calculation method of the migration flux flux′(k, n) is as follows: where Δh k is the height interval of the k-th statistical unit of the custom statistical variable, and ΔT n is the time interval of the n-th statistical unit; If within the minimum statistical unit (k, n), num is detected k,n For the first migratory insects, the formula for flux statistics flux(k, n) is: When the insect radar is actually applied, the average of the flux statistics flux(k, n) is calculated within n time periods, and the flux statistical results Flux(k) of different altitude layers are statistically calculated within N time statistical units. The formula is:

2. The method for statistically calculating the biological migration flux of insects using an insect radar according to claim 1, characterized in that In the second step, calculate the actual distance X i (k,n) that all insects pass through the beam; specifically: Defined at a distance r i The actual measured straight flight distance of the insect is X i (k,n), named the actual distance through the beam; X i (k,n) is calculated by the formula: where SNR min is the minimum detection threshold, and the coefficient C is determined by the hardware of the insect radar, and R i (k,n) is the distance of the i-th insect measured by the radar; θ 3db is the half-power beam 3dB width of the radar; δ i (k,n) is the RCS of the insect measured.

3. The method for statistically calculating the biological migration flux of insect radar according to any one of claims 1 to 2, characterized in that In the third step, the deviation parameter μ i (k,n) is X i (k,n) and D i The ratio of (k,n) is named the deviation coefficient:

4. The method for statistically calculating the biological migration flux of insect radar according to claim 3, characterized in that The deviation coefficient μ of the i-th insect i (k,n), and the derivation result is:

5. The method for statistically calculating the biological migration flux of insects by an insect radar according to claim 1, 2 or 4, characterized in that In the said Step 5, the expression of the migration flux in the vertical measurement fixed beam mode is: The expression of the migration flux in any pointing fixed beam mode is: α represents the elevation angle of the insect radar; In a certain time period, the calculation formula of the flux statistics of all altitudes is the same as that in the vertical measurement mode; The flux statistical results of different altitude layers:

6. The method for statistically calculating the biological migration flux of insects using an insect radar according to claim 5, characterized in that, When the insect radar beam points to an arbitrary pitch angle α and is fixed, within the statistical unit (k, n) interval, the migration flux is:

7. Insect radar biological migration flux statistical device, characterized in that, Including a data acquisition module, a statistical method model module, an actual crossing beam distance solving module, a deviation parameter estimation module, and a migration flux estimation module; The said data acquisition module is used to obtain the data of the insect radar regarding the statistical insect migration flux; The said statistical method model module is used to construct a statistical method model for insect migration flux in the vertical measurement mode, clarify the statistical height interval k and statistical time interval n, and define it as the statistical unit (k, n); The actual crossing beam distance solving module is used to calculate the actual crossing beam distance X of all insects i (k,n); The deviation parameter estimation module is used to establish an estimation model of the radar beam and the position where the migratory insects cross the beam, and based on the horizontal distance D i (k,n) of the longest target beam crossing the beam and the actual beam crossing distance X i (k,n) to obtain the deviation parameter μ i (k,n); The migratory flux estimation module is used to estimate the insect migratory flux by using statistical methods, based on to obtain the flux statistical results of different altitude layers; The said data acquisition module is used to obtain the data of the insect radar regarding the statistical insect migration flux, including the following data: Statistical time length ΔT, where ΔT represents a minimum statistical time period, and statistics are performed every ΔT time; the statistical time series is denoted as (T1, T2, T3, … T n …); The detection beam of the radar is divided into several equal altitude layers according to height, and the height of each layer is Δh; The intermediate height of each height layer is (h1, h2, h3, … h k …); h k is the intermediate height of the k-th height layer; The minimum detection altitude and the maximum detection altitude H of the radar min and H max , the minimum detection distance and the maximum detection distance R of the radar min and R max ; At time T n within the ΔT time interval, at altitude layer h k the number of insects detected by the radar is num k,n , and it is set that the RCSs of the 1st to the num k,n th insects are respectively the distances from the insects to the radar are respectively It is assumed that each insect passes through the radar beam horizontally and can pass through the center of the beam; the horizontal distance at which the echo power within the beam is above the detection threshold is D i (k,n) is the longest distance passing through the beam; The actual crossing beam distance solving module is defined at a distance r i where the actual measured horizontal flight distance of the insect is X i (k,n), named the actual crossing beam distance; X i (k,n) is calculated by the formula: where SNR min is the minimum detection threshold, the coefficient C is determined by the hardware of the insect radar, and R i (k,n) is the distance of the i-th insect measured by the radar; θ 3db is the half-power beam 3dB width of the radar; δ i (k,n) is the RCS of the insect measured; The deviation parameter estimation module, the deviation parameter u i (k,n) is X i (k,n) and D i The ratio of (k,n), named the deviation coefficient: The said migration flux estimation module, when the insect radar beam points to an arbitrary pitch angle α and is fixed, within the statistical unit (k, n) interval, the migration flux is:

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