Sea clutter scattering coefficient estimation method and device based on wave height guided sea condition

Abstract

The invention provides a sea clutter scattering coefficient estimation method and device based on wave height guided sea conditions, and relates to the technical field of radar detection performance evaluation. The method comprises the following steps: determining a true value of a sea clutter scattering coefficient according to radar system parameters; according to the target corresponding relation, the Douglas sea condition, the effective wave height and the multiple coefficients, cubic fitting of the Douglas sea condition and the effective wave height is determined; according to the cubic fitting polynomial, the radar grazing angle, the radar wavelength, the radar sight angle and the wind direction angle, a target sea clutter scattering coefficient estimation model is constructed, and the target sea clutter scattering coefficient estimation model is used for estimating sea clutter scattering coefficient estimation values in the HH polarization mode and the VV polarization mode; according to the true value and the sea clutter scattering coefficient estimation values in the HH polarization mode and the VV polarization mode, the average relative error of the sea clutter scattering coefficients is determined, and the average relative error is used for evaluating radar performance. Therefore, the estimation precision of the sea clutter scattering coefficient is high.

Description

Technical Field

[0001] The present invention relates to the technical field of radar detection performance evaluation, and in particular to a method and device for estimating sea clutter scattering coefficient based on wave height-guided sea conditions. Background Art

[0002] In radar detection of sea targets, environmental clutter, as an unavoidable natural interference, becomes a major factor limiting radar performance. Improving radar target detection performance requires the perception and understanding of the clutter characteristics in the radar detection scene. When detecting sea surface targets, radar inevitably receives backscattered echoes from the sea surface, which are defined as sea clutter. The echo intensity of sea clutter can be expressed as the product of the area of the radar's spatial resolution cell and the average backscatter coefficient of the sea surface within that cell. The area of the radar's spatial resolution cell depends primarily on the radar's spatial resolution and observation geometry, while the average backscatter coefficient within that cell has a complex relationship with radar system parameters, sea surface meteorological conditions, and radar observation geometry. To predict the echo intensity of sea clutter under different radar system parameters and observation environment parameters, the effects of wind speed, wind direction, wave height, wave direction, transmission frequency, polarization mode, and radar observation azimuth and grazing angle on the sea surface backscatter coefficient were analyzed based on collected data. The backscatter coefficient, a fundamental characteristic of sea clutter, is defined as the radar cross-section per square meter of radar-illuminated surface area. The sea clutter scattering coefficient reflects the changing law of sea clutter characteristics and can help set the working parameters of sea radar. Therefore, the estimation of sea clutter scattering coefficient is particularly important.

[0003] Existing technologies estimate the sea clutter scattering coefficient based on parameters such as Douglas sea state, wind direction, grazed angle, polarization, and radar wavelength. The wind direction, grazed angle, and radar wavelength can all vary continuously within a certain range. Polarization is related to the radar operating mode. Douglas sea state is an empirical classification system used to describe ocean surface conditions. It categorizes sea conditions into different levels based on wave height and surface state. Each level corresponds to a certain range of wave heights. For example, a sea radar may collect a set of sea clutter echo data with an effective wave height of 2.5 meters and a set of sea clutter echo data with an effective wave height of 3.5 meters. The parameters, such as polarization, wind direction, grazed angle, and radar wavelength, are identical. However, when estimating the sea clutter scattering coefficient using the conventional estimation model of the prior art, since the effective wave height of 2.5 meters and the effective wave height of 3.5 meters both belong to the Douglas level 5 sea state, the parameters input into the conventional estimation model of the sea clutter scattering coefficient are exactly the same, making it impossible for the conventional estimation model to distinguish between the two sets of data. Ultimately, the estimated sea clutter scattering coefficients are the same, but in fact the sea clutter scattering coefficients of the two sets of data are different, resulting in low estimation accuracy of the sea clutter scattering coefficient. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a method and device for estimating the sea clutter scattering coefficient based on wave height guidance of sea conditions, so as to solve the problem of low estimation accuracy of the sea clutter scattering coefficient.

[0005] To solve the above technical problems, the embodiments of the present invention provide the following technical solutions:

[0006] A first aspect of the present invention provides a method for estimating sea clutter scattering coefficient based on wave height-guided sea conditions, comprising:

[0007] Determine the true value of the sea clutter scattering coefficient based on radar system parameters;

[0008] According to the target corresponding relationship, Douglas sea condition, significant wave height and multiple coefficients, a cubic fitting polynomial of Douglas sea condition and significant wave height is determined, wherein the target corresponding relationship is the corresponding relationship between Douglas sea condition and significant wave height;

[0009] A target sea clutter scattering coefficient estimation model is constructed based on the cubic fitting polynomial, radar ground-grazing angle, radar wavelength, radar line-of-sight angle, and wind direction. The target sea clutter scattering coefficient estimation model is used to estimate the sea clutter scattering coefficient under HH polarization mode and the sea clutter scattering coefficient under VV polarization mode.

[0010] The average relative error of the sea clutter scattering coefficient is determined based on the true value, the estimated value of the sea clutter scattering coefficient under HH polarization mode, and the estimated value of the sea clutter scattering coefficient under VV polarization mode. The average relative error is used to evaluate the radar performance.

[0011] A second aspect of the present invention provides a device for estimating sea clutter scattering coefficient based on wave height-guided sea conditions, comprising:

[0012] A true value determination module, used for determining a true value of the sea clutter scattering coefficient according to radar system parameters;

[0013] a polynomial determination module for determining a cubic fitting polynomial of the Douglas sea condition and the significant wave height based on a target corresponding relationship, the Douglas sea condition, the significant wave height, and a plurality of coefficients, wherein the target corresponding relationship is a corresponding relationship between the Douglas sea condition and the significant wave height;

[0014] A construction module is used to construct a target sea clutter scattering coefficient estimation model based on a cubic fitting polynomial, a radar ground-grazing angle, a radar wavelength, a radar line-of-sight angle, and a wind direction angle. The target sea clutter scattering coefficient estimation model is used to estimate the sea clutter scattering coefficient estimation value under the HH polarization mode and the sea clutter scattering coefficient estimation value under the VV polarization mode;

[0015] The error determination module is used to determine the average relative error of the sea clutter scattering coefficient based on the true value, the estimated value of the sea clutter scattering coefficient under the HH polarization mode, and the estimated value of the sea clutter scattering coefficient under the VV polarization mode. The average relative error is used to evaluate the radar performance.

[0016] Compared with the prior art, the present invention provides a method and device for estimating sea clutter scattering coefficient based on wave height-guided sea conditions. The method and device determine the true value of the sea clutter scattering coefficient based on radar system parameters. A cubic fitting polynomial of the Douglas sea condition and the effective wave height is determined based on a target correspondence, the Douglas sea condition, the effective wave height, and multiple coefficients. The target correspondence is the correspondence between the Douglas sea condition and the effective wave height. A target sea clutter scattering coefficient estimation model is constructed based on the cubic fitting polynomial, the radar ground scraping angle, the radar wavelength, the radar line of sight angle, and the wind direction angle. The target sea clutter scattering coefficient estimation model is used to estimate the estimated value of the sea clutter scattering coefficient under the HH polarization mode and the estimated value of the sea clutter scattering coefficient under the VV polarization mode. The average relative error of the sea clutter scattering coefficient is determined based on the true value, the estimated value of the sea clutter scattering coefficient under the HH polarization mode, and the estimated value of the sea clutter scattering coefficient under the VV polarization mode. The average relative error is used to evaluate radar performance. In this way, the discrete Douglas sea state in the prior art is replaced by a cubic fitting polynomial of the Douglas sea state and the effective wave height, so that the Douglas sea state is changed to a continuous Douglas sea state, and a target sea clutter scattering coefficient estimation model is constructed based on the cubic fitting polynomial containing the continuous Douglas sea state, so that the target sea clutter scattering coefficient estimation model can distinguish the sea clutter scattering coefficients of data belonging to the same level of Douglas sea state and different effective wave heights, so that the estimation accuracy of the sea clutter scattering coefficient is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0018] Figure 1 The flowchart of the method for estimating sea clutter scattering coefficient based on wave height-guided sea conditions is schematically shown;

[0019] Figure 2 The performance comparison of four sea clutter scattering coefficient estimation methods is schematically shown;

[0020] Figure 3 The structure of the device for estimating sea clutter scattering coefficient based on wave height guidance of sea conditions is schematically shown. DETAILED DESCRIPTION

[0021] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0022] It should be noted that, unless otherwise specified, the technical or scientific terms used in the present invention should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0023] The method in the embodiment of the present invention is described in detail below.

[0024] Figure 1 The flowchart of the method for estimating sea clutter scattering coefficient based on wave height guidance sea conditions in an embodiment of the present invention is schematically shown. Figure 1 As shown, the method for estimating the sea clutter scattering coefficient based on wave height-guided sea conditions may include:

[0025] S101. Determine a true value of the sea clutter scattering coefficient based on radar system parameters.

[0026] Among them, the radar system parameters include radar ground-grazing angle, radar receiver bandwidth, radar transmit pulse width, range resolution, radar slant range, radar system constant, radar receive power, radar antenna gain, radar wavelength, radar transmit power and radar antenna azimuth preset beam width.

[0027] The scattering coefficient of sea clutter refers to the average value of the sea surface echo intensity of the radar illumination unit, which is also defined as the normalized radar cross-sectional area of the target sea surface, usually expressed as σ 0 , unit is m 2 The scattering coefficient of sea clutter is an important physical parameter that characterizes the intensity of sea surface echoes and is one of the basic characteristics of sea clutter.

[0028] Based on radar sea clutter test measurement data, using the system constants and radar parameters obtained by radar calibration, the corresponding sea clutter scattering coefficient can be calculated through the radar equation. For sea clutter, the sea clutter scattering coefficient is a relatively uniform surface target, and the single-station radar equation can be expressed as:

[0029]

[0030] Among them, P r is the radar receiving power, P tis the radar transmit power, G is the radar antenna gain, λ is the radar wavelength, r is the radar slant range, L is the radar system constant, σ is the equivalent radar cross section (RCS) of the sea clutter of a single radar resolution unit, σ 0 is the true value of the sea clutter scattering coefficient, A c is the radar resolution unit area.

[0031] For pulse compression radar, the radar receiving power P cannot be directly used. r Since the matched filtering process of pulse compression will produce pulse compression gain, and considering the observation geometry parameters of sea radar detection, the expression of the true value of the sea clutter scattering coefficient is:

[0032]

[0033] Among them, σ 0 is the true value of the sea clutter scattering coefficient, r is the radar slant range, L is the radar system constant, P r is the radar receiving power, φ gr is the radar ground-grazing angle, G is the radar antenna gain, λ is the radar wavelength, P t is the radar transmit power, B is the radar receiver bandwidth, τ is the radar transmit pulse width, Δr is the range resolution, and Δθ is the preset beamwidth of the radar antenna in azimuth. The preset beamwidth can be 3 dB, in which case Δθ is the 3 dB beamwidth of the radar antenna in azimuth.

[0034] S102: Determine a cubic fitting polynomial of the Douglas sea condition and the significant wave height according to the target correspondence, the Douglas sea condition, the significant wave height, and multiple coefficients.

[0035] The target corresponding relationship is the corresponding relationship between the Douglas sea state and the significant wave height. The multiple coefficients include a first coefficient, a second coefficient, a third coefficient, and a fourth coefficient.

[0036] Douglas sea conditions include level 1 to level 7. The correspondence between Douglas sea conditions and significant wave heights is as follows: level 1 Douglas sea conditions correspond to a significant wave height of 0 to 0.305m; level 2 Douglas sea conditions correspond to a significant wave height of 0.305 to 0.914m; level 3 Douglas sea conditions correspond to a significant wave height of 0.914 to 1.524m; level 4 Douglas sea conditions correspond to a significant wave height of 1.524 to 2.438m; level 5 Douglas sea conditions correspond to a significant wave height of 2.438 to 3.660m; level 6 Douglas sea conditions correspond to a significant wave height of 3.660 to 6.096m; and level 7 Douglas sea conditions correspond to a significant wave height of 6.096 to 12.192m.

[0037] Specifically, according to the target correspondence, Douglas sea state, significant wave height and multiple coefficients, a cubic fitting polynomial of Douglas sea state and significant wave height is determined, including:

[0038] Step A1: According to the significant wave height, Douglas sea state, the first coefficient, the second coefficient, the third coefficient and the fourth coefficient, a preset cubic fitting polynomial of the Douglas sea state and the significant wave height is set.

[0039] The effective wave height h 1 / 3 Set as the independent variable, Douglas sea state y as the dependent variable, and set the preset cubic fitting polynomial of Douglas sea state and significant wave height based on the first coefficient, second coefficient, third coefficient and fourth coefficient:

[0040] y=ah 1 / 3 3 +bh 1 / 3 2 +ch 1 / 3 +d;

[0041] Where y is the Douglas sea state, h 1 / 3 is the effective wave height, a is the first coefficient, b is the second coefficient, c is the third coefficient, and d is the fourth coefficient.

[0042] Step A2: Based on the preset cubic fitting polynomial, the minimum sum of squared errors is used to construct the equations for Douglas sea conditions and significant wave height.

[0043] The expression of the equation system is:

[0044]

[0045] Where ∑y is the sum of Douglas sea state level 1 to Douglas sea state level 7, n is the number of data points, ∑h 1 / 3y is the sum of the product of Douglas sea state level 1 and the significant wave height to the product of Douglas sea state level 7 and the significant wave height, ∑h 1 / 3 2 y is the sum of the product of Douglas sea state level 1 and the square of the effective wave height to Douglas sea state level 7 and the square of the effective wave height, ∑h 1 / 3 3 y is the sum of the product of Douglas sea state level 1 and the cube of the significant wave height to Douglas sea state level 7 and the cube of the significant wave height.

[0046] Step A3: Convert the system of equations into a matrix.

[0047] The matrix includes a first coefficient, a second coefficient, a third coefficient and a fourth coefficient.

[0048] The matrix is of the form Ac=B, where c=[a,b,c,d] T , A is the left multiplication matrix, c is the variable to be solved, and B is the right multiplication matrix. The matrix Ac=B is specifically:

[0049]

[0050] Step A4: Based on the correspondence between the Douglas sea state and the significant wave height, matrix operations are used to solve the coefficient values corresponding to the first coefficient, the second coefficient, the third coefficient, and the fourth coefficient.

[0051] Specifically, the correspondence between Douglas sea state level 1 to Douglas sea state level 7 and the significant wave height is substituted into the above matrix, and the coefficient value corresponding to the first coefficient a is solved through matrix operation to be 0.0058, the coefficient value corresponding to the second coefficient b is 0.18, the coefficient value corresponding to the third coefficient c is 1.8, and the coefficient value corresponding to the fourth coefficient d is 1.1.

[0052] Step A5: Substitute the coefficient values into the preset cubic fitting polynomial to obtain the cubic fitting polynomial.

[0053] Substitute the coefficient value corresponding to the first coefficient a as 0.0058, the coefficient value corresponding to the second coefficient b as 0.18, the coefficient value corresponding to the third coefficient c as 1.8, and the coefficient value corresponding to the fourth coefficient d as 1.1 into the preset cubic fitting polynomial to obtain the expression of the cubic fitting polynomial:

[0054] y=0.0058h 1 / 3 3 -0.18h 1 / 3 2 +1.8h 1 / 3 +1.1;

[0055] Where y is the Douglas sea state, h1 / 3 is the effective wave height.

[0056] S103: Construct a target sea clutter scattering coefficient estimation model based on a cubic fitting polynomial, radar ground-grazing angle, radar wavelength, radar line-of-sight angle, and wind direction angle.

[0057] The target sea clutter scattering coefficient estimation model is used to estimate the sea clutter scattering coefficient estimation value under the horizontal transmission and horizontal reception (Horizontal Transmission and Horizontal Reception, HH) polarization mode and the sea clutter scattering coefficient estimation value under the vertical transmission and vertical reception (Vertical Transmission and Vertical Reception, VV) polarization mode.

[0058] The target sea clutter scattering coefficient estimation model is based on complex environments and radar parameters. The target sea clutter scattering coefficient estimation model is based on fitting Nathanson data, averaging the Nathanson data in all observation directions, and assuming that the Nathanson data used is crosswind data.

[0059] A target sea clutter scattering coefficient estimation model is constructed based on the cubic fitting polynomial, radar ground-grazing angle, radar wavelength, radar line-of-sight angle, and wind direction angle, including:

[0060] Step B1: Determine a grazing angle factor based on a first preset power of a cubic fitting polynomial, a radar grazing angle, and a radar wavelength.

[0061] Specifically, step B1 includes:

[0062] Step B11: determining the standard deviation of the sea level height according to the first preset power of the cubic fitting polynomial;

[0063] Step B12: Determine a ground-grazing angle correction factor based on the sea surface height standard deviation, the radar ground-grazing angle, and the radar wavelength;

[0064] Step B13: Determine the rubbing angle factor according to the rubbing angle correction factor.

[0065] Step B2: determining a wind speed factor according to the second preset power of the cubic fitting polynomial, the radar ground-grazing angle, and the radar wavelength.

[0066] Specifically, step B2 includes:

[0067] Step B21: determining the wind speed according to the second preset power of the cubic fitting polynomial;

[0068] Step B22: Determine a wind speed correction factor based on the radar ground-grazing angle and the radar wavelength;

[0069] Step B23: Determine the wind speed factor according to the wind speed and the wind speed correction factor.

[0070] Step B3: Determine the wind direction factor based on the radar ground-grazing angle, radar line-of-sight angle, wind direction angle, and radar wavelength.

[0071] Step B4: Determine an estimated value of the sea clutter scattering coefficient in the HH polarization mode based on the ground-grazing angle factor, wind speed factor, wind direction factor, and radar ground-grazing angle.

[0072] Step B5: Determine the estimated value of the sea clutter scattering coefficient in the VV polarization mode based on the radar wavelength, the radar grazing angle, and the estimated value of the sea clutter scattering coefficient in the HH polarization mode, so as to construct a target sea clutter scattering coefficient estimation model.

[0073] The unit of the estimated sea clutter scattering coefficient under HH polarization mode and VV polarization mode is dBm. 2 / m 2 .

[0074] The expression of the target sea clutter scattering coefficient estimation model is:

[0075]

[0076]

[0077] Among them, G A (φ gr ,h 1 / 3 ,λ) is the ground-grabbing angle factor, that is, the radar ground-grabbing angle φ gr 、Effective wave height h 1 / 3 and the ground angle factor under the radar wavelength λ, φ gr For radar wiping angle, h 1 / 3 is the effective wave height, λ is the radar wavelength, σ α is the ground-rubbing angle correction factor, σ z is the standard deviation of sea surface height, (0.0058h 1 / 3 3 -0.18h 1 / 3 2 +1.8h 1 / 3 +1.1) 1.95 is the first preset power of the cubic fitting polynomial, where the first preset power is 1.95, G w (φ gr ,h 1 / 3 ,λ) is the wind speed factor, that is, the radar ground-grazing angle φ gr 、Effective wave height h 1 / 3and wind speed factor at radar wavelength λ, v w is the wind speed, A is the wind speed correction factor, Q is the reference ground-rubbing angle, (0.0058h 1 / 3 3 -0.18h 1 / 3 2 +1.8h 1 / 3 +1.1) 0.8 is the second preset power of the cubic fitting polynomial, the second preset power is 0.8, G u (φ gr ,θ,θ w ,λ) is the wind direction factor, that is, the radar ground-grazing angle φ gr , radar sight angle θ, wind direction angle θ w and wind direction factor under the conditions of radar wavelength λ, θ is the radar line of sight angle, θ w is the wind direction angle, is the estimated value of the sea clutter scattering coefficient under HH polarization mode, is the estimated value of the sea clutter scattering coefficient under VV polarization mode.

[0078] S104 . Determine an average relative error of the sea clutter scattering coefficient according to the true value, the estimated value of the sea clutter scattering coefficient under the HH polarization mode, and the estimated value of the sea clutter scattering coefficient under the VV polarization mode.

[0079] Among them, the average relative error (ARE) is used to evaluate radar performance.

[0080] The expression of the average relative error of the sea clutter scattering coefficient is:

[0081]

[0082] Where ARE is the average relative error of the sea clutter scattering coefficient, n′ is the number of samples, i is the i-th sample, σ 0 is the true value of the sea clutter scattering coefficient, is the estimated value of the sea clutter scattering coefficient under HH polarization mode, is the estimated value of the sea clutter scattering coefficient under VV polarization mode.

[0083] Using a sea clutter scattering coefficient estimation model based on empirical parameters and the target sea clutter scattering coefficient estimation model of the present invention, i.e., a sea clutter scattering coefficient estimation model based on complex environments and radar parameters, to classify the sea conditions associated with significant wave height, an average relative error of the classified sea clutter scattering coefficient can be obtained. The average relative error of the classified sea clutter scattering coefficient using the sea clutter scattering coefficient estimation model based on empirical parameters is 25.54%, while the average relative error of the classified sea clutter scattering coefficient using the target sea clutter scattering coefficient estimation model of the present invention is 4.35%. This average relative error of the classified sea clutter scattering coefficient indicates that the sea clutter scattering coefficient estimation method based on wave height-guided sea conditions, including the target sea clutter scattering coefficient estimation model, employed in the present invention, has superior performance.

[0084] The sea clutter scattering coefficient estimation model based on the existing technology of ground-grazing angle and sea conditions, the sea clutter scattering coefficient estimation model based on multipath and measured data, the sea clutter scattering coefficient estimation model based on empirical parameters, and the target sea clutter scattering coefficient estimation model of the present invention are used to estimate the sea clutter scattering coefficient of the measured data, and the estimation performance is measured by ARE. Figure 2 The performance comparison of four sea clutter scattering coefficient estimation methods is shown schematically, see Figure 2 As shown, Figure 2 (a) is a performance comparison chart of the sea clutter scattering coefficient estimation model based on the ground-grazing angle and sea conditions. Figure 2 (b) is a performance comparison chart of the sea clutter scattering coefficient estimation model based on multipath and measured data. Figure 2 (c) is a performance comparison chart of the sea clutter scattering coefficient estimation model based on empirical parameters. Figure 2 (d) is a performance comparison diagram of the target sea clutter scattering coefficient estimation model of the present invention, Figure 2 The horizontal axes of (a) to (d) are the true scattering coefficients, that is, the true values of the sea clutter scattering coefficients, and the vertical axes are the predicted scattering coefficients, that is, the estimated values of the sea clutter scattering coefficients under the HH polarization mode and the estimated values of the sea clutter scattering coefficients under the VV polarization mode. Figure 2 The ARE of (a) is 35.13%, Figure 2 The ARE of (b) is 17.98%, Figure 2 The ARE of (c) is 8.76%, Figure 2 The ARE of (d) is 8.07%. It can be seen that the average relative error of the sea clutter scattering coefficient estimation method based on wave height-guided sea conditions of the present invention is 8.07%, which is much better than the other three existing models.

[0085] Based on the above Figure 1As can be seen from the implementation method, the embodiment of the present invention determines the true value of the sea clutter scattering coefficient based on the radar system parameters; determines the cubic fitting polynomial of the Douglas sea condition and the effective wave height based on the target correspondence, the Douglas sea condition, the effective wave height, and multiple coefficients, where the target correspondence is the correspondence between the Douglas sea condition and the effective wave height; constructs a target sea clutter scattering coefficient estimation model based on the cubic fitting polynomial, the radar ground scraping angle, the radar wavelength, the radar line of sight angle, and the wind direction angle; the target sea clutter scattering coefficient estimation model is used to estimate the estimated value of the sea clutter scattering coefficient under the HH polarization mode and the estimated value of the sea clutter scattering coefficient under the VV polarization mode; determines the average relative error of the sea clutter scattering coefficient based on the true value, the estimated value of the sea clutter scattering coefficient under the HH polarization mode, and the estimated value of the sea clutter scattering coefficient under the VV polarization mode, and the average relative error is used to evaluate radar performance. In this way, the discrete Douglas sea state in the prior art is replaced by a cubic fitting polynomial of the Douglas sea state and the effective wave height, so that the Douglas sea state is changed to a continuous Douglas sea state, and a target sea clutter scattering coefficient estimation model is constructed based on the cubic fitting polynomial containing the continuous Douglas sea state, so that the target sea clutter scattering coefficient estimation model can distinguish the sea clutter scattering coefficients of data belonging to the same level of Douglas sea state and different effective wave heights, so that the estimation accuracy of the sea clutter scattering coefficient is higher.

[0086] Based on the same inventive concept, as an implementation of the above-mentioned method for estimating the sea clutter scattering coefficient based on wave height guidance of sea conditions, an embodiment of the present invention further provides a device for estimating the sea clutter scattering coefficient based on wave height guidance of sea conditions. Figure 3 This is a structural diagram of a device for estimating sea clutter scattering coefficient based on wave height guidance of sea conditions in an embodiment of the present invention, see Figure 3 As shown, the sea clutter scattering coefficient estimation device based on wave height-guided sea conditions may include:

[0087] A true value determination module 301 is used to determine the true value of the sea clutter scattering coefficient based on radar system parameters;

[0088] a polynomial determination module 302 for determining a cubic fitting polynomial of the Douglas sea condition and the significant wave height based on a target correspondence relationship, the Douglas sea condition, the significant wave height, and a plurality of coefficients, wherein the target correspondence relationship is a correspondence relationship between the Douglas sea condition and the significant wave height;

[0089] A construction module 303 is configured to construct a target sea clutter scattering coefficient estimation model based on a cubic fitting polynomial, a radar ground-grazing angle, a radar wavelength, a radar line-of-sight angle, and a wind direction angle. The target sea clutter scattering coefficient estimation model is configured to estimate an estimated value of the sea clutter scattering coefficient under an HH polarization mode and an estimated value of the sea clutter scattering coefficient under a VV polarization mode.

[0090] The error determination module 304 is configured to determine an average relative error of the sea clutter scattering coefficient based on the true value, the estimated value of the sea clutter scattering coefficient under the HH polarization mode, and the estimated value of the sea clutter scattering coefficient under the VV polarization mode. The average relative error is used to evaluate radar performance.

[0091] In the true value determination module 301, the true value of the sea clutter scattering coefficient is expressed as:

[0092]

[0093] Among them, σ 0 is the true value of the sea clutter scattering coefficient, r is the radar slant range, L is the radar system constant, P r is the radar receiving power, φ gr is the radar ground-grazing angle, G is the radar antenna gain, λ is the radar wavelength, P t is the radar transmit power, B is the radar receiver bandwidth, τ is the radar transmit pulse width, Δr is the range resolution, and Δθ is the radar antenna azimuth preset beam width.

[0094] The polynomial determination module 302 is specifically used to set a preset cubic fitting polynomial for the Douglas sea condition and the effective wave height based on the effective wave height, the Douglas sea condition, the first coefficient, the second coefficient, the third coefficient, and the fourth coefficient; based on the preset cubic fitting polynomial, a minimum sum of square errors is used to construct an equation group for the Douglas sea condition and the effective wave height; the equation group is converted into a matrix, where the matrix includes the first coefficient, the second coefficient, the third coefficient, and the fourth coefficient; based on the corresponding relationship between the Douglas sea condition and the effective wave height, a matrix operation is used to solve the coefficient values corresponding to the first coefficient, the second coefficient, the third coefficient, and the fourth coefficient; and the coefficient values are substituted into the preset cubic fitting polynomial to obtain the cubic fitting polynomial.

[0095] Polynomial determination module 302, the expression of the cubic fitting polynomial is:

[0096] y=0.0058h 1 / 3 3 -0.18h 1 / 3 2 +1.8h 1 / 3 +1.1;

[0097] Where y is the Douglas sea state, h 1 / 3 is the effective wave height.

[0098] Construction module 303 is specifically configured to determine a grazing angle factor based on a first preset power of the cubic fitting polynomial, the radar grazing angle, and the radar wavelength; determine a wind speed factor based on a second preset power of the cubic fitting polynomial, the radar grazing angle, and the radar wavelength; determine a wind direction factor based on the radar grazing angle, the radar line of sight angle, the wind direction angle, and the radar wavelength; determine an estimated value of the sea clutter scattering coefficient in HH polarization mode based on the grazing angle factor, the wind speed factor, the wind direction factor, and the radar grazing angle; and determine an estimated value of the sea clutter scattering coefficient in VV polarization mode based on the radar wavelength, the radar grazing angle, and the estimated value of the sea clutter scattering coefficient in HH polarization mode, so as to construct a target sea clutter scattering coefficient estimation model.

[0099] Construction module 303 determines a ground-grazing angle factor based on a first preset power of a cubic fitting polynomial, the radar ground-grazing angle, and the radar wavelength, including: determining a sea surface height standard deviation based on the first preset power of the cubic fitting polynomial; determining a ground-grazing angle correction factor based on the sea surface height standard deviation, the radar ground-grazing angle, and the radar wavelength; and determining the ground-grazing angle factor based on the ground-grazing angle correction factor.

[0100] Module 303 is constructed to determine a wind speed factor based on a second preset power of a cubic fitting polynomial, the radar ground-grazing angle, and the radar wavelength, including: determining the wind speed based on the second preset power of the cubic fitting polynomial; determining a wind speed correction factor based on the radar ground-grazing angle and the radar wavelength; and determining the wind speed factor based on the wind speed and the wind speed correction factor.

[0101] In the construction module 303, the target sea clutter scattering coefficient estimation model is expressed as:

[0102]

[0103]

[0104] Among them, G A (φ gr ,h 1 / 3 ,λ) is the floor rubbing angle factor, φ gr For radar wiping angle, h 1 / 3 is the effective wave height, λ is the radar wavelength, σ α is the ground-rubbing angle correction factor, σ z is the standard deviation of sea surface height, (0.0058h 1 / 3 3 -0.18h 1 / 3 2 +1.8h 1 / 3 +1.1) 1.95 is the first preset power of the cubic fitting polynomial, where the first preset power is 1.95, G w (φ gr ,h 1 / 3,λ) is the wind speed factor, v w is the wind speed, A is the wind speed correction factor, Q is the reference ground-rubbing angle, (0.0058h 1 / 3 3 -0.18h 1 / 3 2 +1.8h 1 / 3 +1.1) 0.8 is the second preset power of the cubic fitting polynomial, the second preset power is 0.8, G u (φ gr ,θ,θ w ,λ) is the wind direction factor, θ is the radar sight angle, θ w is the wind direction angle, is the estimated value of the sea clutter scattering coefficient under HH polarization mode, is the estimated value of the sea clutter scattering coefficient under VV polarization mode.

[0105] It should be noted that the above description of the embodiment of the apparatus for estimating sea clutter scattering coefficients based on wave height guidance is similar to the description of the embodiment of the method for estimating sea clutter scattering coefficients based on wave height guidance, and has similar beneficial effects as the embodiment of the method for estimating sea clutter scattering coefficients based on wave height guidance. For technical details not disclosed in the embodiment of the apparatus for estimating sea clutter scattering coefficients based on wave height guidance, please refer to the description of the embodiment of the method for estimating sea clutter scattering coefficients based on wave height guidance of the present invention for understanding.

[0106] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for estimating sea clutter scattering coefficient based on wave height guidance of sea conditions, characterized in that: include: Determine the true value of the sea clutter scattering coefficient based on radar system parameters; Determining a cubic fitting polynomial of the Douglas sea condition and the significant wave height according to a target corresponding relationship, the Douglas sea condition, the significant wave height, and a plurality of coefficients, wherein the target corresponding relationship is a corresponding relationship between the Douglas sea condition and the significant wave height; Constructing a target sea clutter scattering coefficient estimation model according to the cubic fitting polynomial, the radar ground-grazing angle, the radar wavelength, the radar line-of-sight angle, and the wind direction angle, wherein the target sea clutter scattering coefficient estimation model is used to estimate an estimated value of the sea clutter scattering coefficient under an HH polarization mode and an estimated value of the sea clutter scattering coefficient under a VV polarization mode; An average relative error of the sea clutter scattering coefficient is determined according to the true value, the estimated value of the sea clutter scattering coefficient in the HH polarization mode, and the estimated value of the sea clutter scattering coefficient in the VV polarization mode. The average relative error is used to evaluate radar performance.

2. The method for estimating sea clutter scattering coefficient based on wave height-guided sea conditions according to claim 1, characterized in that: The radar system parameters include the radar ground-grazing angle, radar receiver bandwidth, radar transmit pulse width, range resolution, radar slant range, radar system constant, radar receive power, radar antenna gain, the radar wavelength, radar transmit power and radar antenna azimuth preset beam width.

3. The method for estimating sea clutter scattering coefficient based on wave height-guided sea conditions according to claim 2, characterized in that: The true value of the sea clutter scattering coefficient is expressed as: Among them, σ 0 is the true value of the sea clutter scattering coefficient, r is the radar slant range, L is the radar system constant, P r is the radar received power, φ gr is the radar ground-grazing angle, G is the radar antenna gain, λ is the radar wavelength, P t is the radar transmit power, B is the radar receiver bandwidth, τ is the radar transmit pulse width, Δr is the range resolution, and Δθ is the radar antenna azimuth preset beam width.

4. The method for estimating sea clutter scattering coefficient based on wave height-guided sea conditions according to claim 1, characterized in that: The multiple coefficients include a first coefficient, a second coefficient, a third coefficient, and a fourth coefficient. Determining a cubic fitting polynomial of the Douglas sea condition and the significant wave height based on the target correspondence, the Douglas sea condition, the significant wave height, and the multiple coefficients includes: Setting a preset cubic fitting polynomial for the Douglas sea condition and the significant wave height according to the significant wave height, the Douglas sea condition, the first coefficient, the second coefficient, the third coefficient, and the fourth coefficient; Based on the preset cubic fitting polynomial, a system of equations for the Douglas sea state and the significant wave height is constructed using a minimum sum of square errors; Converting the system of equations into a matrix, wherein the matrix includes the first coefficient, the second coefficient, the third coefficient, and the fourth coefficient; Based on the correspondence between the Douglas sea state and the significant wave height, using matrix operations to solve coefficient values corresponding to the first coefficient, the second coefficient, the third coefficient, and the fourth coefficient; Substituting the coefficient value into the preset cubic fitting polynomial to obtain the cubic fitting polynomial.

5. The method for estimating sea clutter scattering coefficient based on wave height-guided sea conditions according to claim 4, characterized in that: The expression of the cubic fitting polynomial is: y=0.0058h 1 / 3 3 -0.18h 1 / 3 2 +1.8h 1 / 3 +1.1; Where y is the Douglas sea state, h 1 / 3 is the effective wave height.

6. The method for estimating sea clutter scattering coefficient based on wave height-guided sea conditions according to claim 1, characterized in that: The method of constructing a target sea clutter scattering coefficient estimation model based on the cubic fitting polynomial, the radar ground-grazing angle, the radar wavelength, the radar line-of-sight angle, and the wind direction angle includes: determining a grazing angle factor according to a first preset power of the cubic fitting polynomial, the radar grazing angle, and the radar wavelength; determining a wind speed factor based on a second preset power of the cubic fitting polynomial, the radar ground-grazing angle, and the radar wavelength; determining a wind direction factor according to the radar ground-grazing angle, the radar sight angle, the wind direction angle, and the radar wavelength; determining an estimated value of the sea clutter scattering coefficient in the HH polarization mode according to the ground-grazing angle factor, the wind speed factor, the wind direction factor, and the radar ground-grazing angle; The estimated value of the sea clutter scattering coefficient in the VV polarization mode is determined according to the radar wavelength, the radar ground-grazing angle, and the estimated value of the sea clutter scattering coefficient in the HH polarization mode, so as to construct the target sea clutter scattering coefficient estimation model.

7. The method for estimating sea clutter scattering coefficient based on wave height-guided sea conditions according to claim 6, characterized in that: The determining of the grazing angle factor according to the first preset power of the cubic fitting polynomial, the radar grazing angle, and the radar wavelength includes: determining a standard deviation of sea level height according to a first preset power of the cubic fitting polynomial; determining a ground-grazing angle correction factor according to the sea surface height standard deviation, the radar ground-grazing angle, and the radar wavelength; The rubbing angle factor is determined according to the rubbing angle correction factor.

8. The method for estimating sea clutter scattering coefficient based on wave height-guided sea conditions according to claim 6, characterized in that: The determining of the wind speed factor according to the second preset power of the cubic fitting polynomial, the radar ground-grazing angle, and the radar wavelength includes: determining a wind speed according to a second predetermined power of the cubic fitting polynomial; determining a wind speed correction factor according to the radar ground-grazing angle and the radar wavelength; The wind speed factor is determined according to the wind speed and the wind speed correction factor.

9. The method for estimating sea clutter scattering coefficient based on wave height-guided sea conditions according to claim 6, characterized in that: The expression of the target sea clutter scattering coefficient estimation model is: s z =0.03505(0.0058h 1 / 3 3 -0.18h 1 / 3 2 +1.8h 1 / 3 +1.1) 1.95 <h2 style=";text-align:left;direction:ltr">v<h2 style=";text-align:left;direction:ltr"> w <h2 style=";text-align:left;direction:ltr"> 3.189(0.0058h<h2 style=";text-align:left;direction:ltr"> 1 / 3 <h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> -0.18h<h2 style=";text-align:left;direction:ltr"> 1 / 3 <h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +1.8h<h2 style=";text-align:left;direction:ltr"> 1 / 3 <h2 style=";text-align:left;direction:ltr"> +1.1)<h2 style=";text-align:left;direction:ltr"> 0.8 Among them, GA(φ gr ,h 1 / 3 ,λ) is the rubbing angle factor, φ gr is the radar ground-grazing angle, h 1 / 3 is the effective wave height, λ is the radar wavelength, σ α is the ground-rubbing angle correction factor, σ z is the standard deviation of sea surface height, (0.0058h 1 / 3 3 -0.18h 1 / 3 2 +1.8h 1 / 3 +1.1) 1.95 is the first preset power of the cubic fitting polynomial, wherein the first preset power is 1.95, G w (φ gr ,h 1 / 3 ,λ) is the wind speed factor, v w is the wind speed, A is the wind speed correction factor, Q is the reference ground-rubbing angle, (0.0058h 1 / 3 3 -0.18h 1 / 3 2 +1.8h 1 / 3 +1.1) 0.8 is the second preset power of the cubic fitting polynomial, the second preset power is 0.8, G u (φ gr ,θ,θ w ,λ) is the wind direction factor, θ is the radar sight angle, θ w is the wind direction angle, is the estimated value of the sea clutter scattering coefficient under the HH polarization mode, is the estimated value of the sea clutter scattering coefficient under the VV polarization mode.

10. A device for estimating sea clutter scattering coefficient based on wave height guidance of sea conditions, characterized in that: include: A true value determination module, used for determining a true value of the sea clutter scattering coefficient according to radar system parameters; a polynomial determination module, configured to determine a cubic fitting polynomial of the Douglas sea condition and the significant wave height according to a target corresponding relationship, the Douglas sea condition, the significant wave height, and a plurality of coefficients, wherein the target corresponding relationship is a corresponding relationship between the Douglas sea condition and the significant wave height; a construction module, configured to construct a target sea clutter scattering coefficient estimation model based on the cubic fitting polynomial, the radar ground-grazing angle, the radar wavelength, the radar line-of-sight angle, and the wind direction angle, wherein the target sea clutter scattering coefficient estimation model is used to estimate an estimated value of the sea clutter scattering coefficient under an HH polarization mode and an estimated value of the sea clutter scattering coefficient under a VV polarization mode; an error determination module, configured to determine an average relative error of the sea clutter scattering coefficient based on the true value, the estimated value of the sea clutter scattering coefficient in the HH polarization mode, and the estimated value of the sea clutter scattering coefficient in the VV polarization mode, wherein the average relative error is used to evaluate radar performance.

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