A Method for Identifying and Suppressing False Echoes from Marine Radar Under Calm Sea Surface

Abstract

This invention provides a method for identifying and suppressing false echoes from marine radar under calm sea conditions. The specific process is as follows: For a single-frame radar image, extended target information is obtained. The recorded extended target information is converted into point coordinate information, i.e., the wave crest position of the echo is retained, and the azimuth and range information of the wave crest position are extracted. Simultaneously, the echo intensity information of the target is added and stored as an initial target information matrix. Azimuth feature information is judged, and target information that conforms to the azimuth feature of the false echo is saved. Range feature information is judged, and target information that conforms to the range feature of the false echo is saved. The false echo occurrence scenario is judged to determine whether the conditions for false echo occurrence are met. Echo intensity feature information is judged, and target information that does not conform to the echo intensity feature of the false echo is deleted. Simultaneously, the initial target information matrix is ​​updated to a false echo target information matrix. Based on the information in the false echo target information matrix, a suppression threshold for the digital domain of the radar echo data is set to suppress false echoes in the single-frame target information.

Description

Technical Field

[0001] This invention relates to the technical field of identification methods, and more particularly to a method for identifying and suppressing false echoes from marine radar under calm sea surfaces. Background Technology

[0002] With the increasing number and size of ships, in practical applications of radar target detection and tracking, rough water surfaces, tall buildings, and other surface vessels can cause multipath propagation of radar-emitted electromagnetic waves. Furthermore, the reflected echoes may be received by the radar receiver, resulting in false target echoes. Therefore, methods for identifying and suppressing false echoes are crucial for correctly processing target echoes and eliminating false target echoes, ultimately improving the accuracy and reliability of radar-acquired information. Summary of the Invention

[0003] In view of the technical problems mentioned in the background section, this invention provides a method for identifying and suppressing false radar echoes under calm sea conditions. The invention primarily utilizes a false echo identification and suppression method to effectively identify and suppress radar false echoes in the aforementioned scenarios, thereby reducing the adverse effects of false radar echoes. The technical means employed in this invention are as follows:

[0004] A method for identifying and suppressing false echoes from marine radar beneath a calm sea surface includes the following steps:

[0005] Step 1: For a single-frame radar image, based on the accumulation of multi-pulse echoes from the radar target, data is read from each range cell along the azimuth dimension to save the range and azimuth information of the appearance and disappearance of the extended target, thereby obtaining the information matrix of the extended target;

[0006] Step 2: Convert the extended target information matrix into point coordinate information, that is, retain the echo crest position, extract the azimuth feature information and distance feature information of the crest position, and add the echo intensity feature information of the target, and store it as the initial target information matrix;

[0007] Step 3: Extract the first column of azimuth feature information from the initial target information matrix and make a judgment. Determine the azimuth feature information, save the target information that matches the false echo azimuth feature, and update the target information matrix.

[0008] Step 4: Extract the distance feature information from the second column of the initial target information matrix and make a judgment. Determine the distance feature information, save the target information that matches the false echo distance feature, and update the target information matrix.

[0009] Step 5: Introduce the judgment of false echo occurrence scenario. By converting the polar coordinate information composed of azimuth and distance in the initial target information matrix and the fixed strong reflector into rectangular coordinates, and judging whether the distance between targets and between targets and strong reflectors are approximately equal, the false echo occurrence scenario is judged, whether the conditions for false echo occurrence are met, and the target information matrix is ​​updated.

[0010] Step 6: Extract the echo intensity information from the latest target information matrix, determine whether the new target information matrix conforms to the intensity information characteristics of false echoes, delete the target information that does not conform to the echo intensity characteristics of false echoes, and update the initial target information matrix to the false echo target information matrix.

[0011] Step 7: Based on the information in the false echo target information matrix, set the suppression threshold of the radar echo data digital domain to suppress false echoes in single-frame target information.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] This invention enables false echo recognition in individual scenarios such as moving ship targets, fixed strong reflectors, and sea surface reflections.

[0014] This invention achieves false echo suppression in individual scenarios such as moving ship target reflectors, fixed strong reflectors, and sea surface reflections.

[0015] It enables false echo recognition when multiple scenarios, including moving ship targets, fixed strong reflectors, and sea surface reflections, occur simultaneously.

[0016] It achieves false echo suppression when multiple scenarios such as moving ship targets, fixed strong reflectors, and sea surface reflections occur simultaneously. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall process of the present invention.

[0019] Figure 2 This is the original data image for the nth scan line.

[0020] Figure 3 The image shows the data after sham echo transplantation for the nth scan.

[0021] Figure 4 Examples and enlarged views of false echoes in a scenario involving a moving ship target reflector.

[0022] Figure 5 The images show examples and magnified views of the reflections from moving ship targets after false echo identification and suppression.

[0023] Figure 6 Examples and magnified views of false echoes in a fixed, strongly reflective scene.

[0024] Figure 7 The images show examples and magnified views of a fixed, strongly reflective object scene after false echo identification and suppression.

[0025] Figure 8 Examples and magnified views of false echoes in a sea surface reflection scenario.

[0026] Figure 9 The images show examples and magnified views of the sea surface reflection scene after false echo identification and suppression.

[0027] Figure 10 Examples and enlarged views of false echoes when moving ship targets, fixed strong reflectors, and sea surface reflections occur simultaneously.

[0028] Figure 11 Examples and magnified views of the images are provided after false echo identification and suppression when multiple scenarios, including moving ship targets, fixed strong reflectors, and sea surface reflections, occur simultaneously. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments derived therefrom should fall within the protection scope of the present invention.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] like Figure 1-11 As shown, this invention provides a method for identifying and suppressing false echoes from marine radar under calm sea surfaces, comprising the following steps:

[0032] Step 1: For a single-frame radar image, based on the accumulation of multi-pulse echoes from the radar target, data is read from each range cell along the azimuth dimension. The range and azimuth information at the times of the extended target's appearance and disappearance are saved to obtain the extended target's information matrix. During radar rotation, signals are continuously emitted outwards, and the receiver receives the echo signals emitted by the radar and reflected back by reflectors (targets, sea surfaces, etc.). Each rotation of the radar quantizes the azimuth data to 4096 azimuth resolution cells in polar coordinates, and each azimuth cell is quantized into 2048 range resolution cells. Therefore, the radar data frame format acquired per rotation is a data matrix (.bin).

[0033] In step 1,

[0034] Extended target information is acquired sequentially along the azimuth dimension for the j-th (0≤j≤2048) range resolution cell on the i-th (0≤i≤4096) azimuth resolution cell, and the minimum azimuth θ for storing the extended target azimuth information is recorded. leftn Maximum azimuth θ rightn The nearest distance ρ to the distance information downn The furthest distance ρ upn To expand the target information matrix Ω extend ,for:

[0035]

[0036] Where 0≤θ≤4096, 0≤ρ≤2048; n represents the target label, i.e., the number, and n∈[1,N], while N∈[0,+∞).

[0037] Step 2: Convert the extended target information matrix into point coordinate information, that is, retain the echo crest position, extract the azimuth feature information and distance feature information of the crest position, and add the target echo intensity feature information, and store it as the initial target information matrix; Step 2 also includes the following steps:

[0038] Step 21: Convert the expanded target into a point target;

[0039] For azimuth information, the difference between the first and second columns of the data matrix (1) is calculated and denoted as θ. dif , that is, θ dif =θ rightn -θ leftn Then, the difference θ obtained is... difTaking the median and rounding down, we get

[0040] For distance information, the difference between the third and fourth columns of the data matrix (1) is calculated and denoted as ρ. dif , i.e., ρ dif =ρ upn -ρ downn Then, the difference ρ obtained is... dif Taking the median and rounding down, we get

[0041] The processed azimuth and distance information are combined into new polar coordinate information, which is the polar coordinate information of the point target, denoted as (θ). pn ,ρ pn );

[0042] Step 22: Let k represent the echo intensity. The formula for calculating the echo intensity k is:

[0043] k = (i right -i left )×(j up -j down (2);

[0044] In the formula, i right Indicates the rightmost position of the target, i left Indicates the leftmost position of the target; j up j represents the farthest distance from the target. down This indicates the nearest distance to the target. The echo intensity value is then obtained, representing the number of resolution cells occupied by the target echo.

[0045] Step 23: Update the initial target information matrix to Ω based on the polar coordinates of the point target. point ,for:

[0046]

[0047] Where n is the label of the target, i.e., the number, and n∈[1,N], while N∈[0,+∞).

[0048] Step 3: Extract the azimuth feature information from the first column of the initial target information matrix and perform discrimination to determine the azimuth feature information, save the target information that conforms to the false echo azimuth feature, and update the target information matrix; Step 3 also includes the following steps:

[0049] Step 31: Traverse Ω point The azimuth information θ pn For Ω point The azimuth information θ of the (n+1)th target p(n+1) Determine the target and Ω extendThe minimum azimuth θ of the nth target's azimuth information leftn Maximum azimuth θ rightn Do they satisfy the orientation condition θ? leftn ≤θ p(n+1) ≤θ rightn ;

[0050] Step 32: For Ω point The target information that meets the orientation conditions is saved into a new matrix Ω. fp1 In this context, it is defined as the azimuth determination target information matrix, and in Ω fp1 Add suspected false echo group labeling information to the data, as follows:

[0051]

[0052] Where a, b, c represent the target labels that meet the azimuth conditions, m represents the group label information of the suspected false echo, i.e., the group number, and a, b, c, m ∈ [1, N].

[0053] Step 33: For Ω point If the target information does not meet the orientation conditions, it will be ignored.

[0054] Step 4: Extract the distance feature information from the second column of the initial target information matrix and perform discrimination to determine the distance feature information, save the target information that conforms to the false echo distance feature, and update the target information matrix; Step 4 also includes the following steps:

[0055] Step 41: For Ω fp0 Target information that does not meet the distance criteria will be deleted directly.

[0056] Step 42: Retain Ω fp0 The target information that meets the distance condition is obtained, and the matrix Ω is updated. fp0 For the new matrix Ω fp1 The updated matrix Ω fp1 Defined as a distance-based target information matrix, as follows:

[0057]

[0058] Where a and c represent the target labels that meet the azimuth conditions, m represents the group label information of the suspected false echo, i.e., the group number, which is obtained from the azimuth information, and a, c, m ∈ [1, N].

[0059] In step 4, according to matrix Ω fp0 The group number column information and the group traversal distance information ρ are included. pn For Ω fp0 Distance information ρ of the (n+1)th target p(n+1) Calculate their relative distance ρp(n+1) -ρ pn For the (n+2)th target in the suspected false echo group, according to matrix Ω fp0 Target label information and distance information ρ p(n+2) Calling and Ω extend The nearest distance ρ of the (n+1)th target distance information downn The furthest distance ρ upn Substitute the above parameters into the azimuth condition relationship ρ p(n+1) -ρ downn ≤ρ p(n+2) -ρ p(n≤+1) ≤ρ p(n+1) -ρ upn In the middle, it is determined whether the conditions are met; for the (n+p)th target in the suspected false echo group, the same logic applies when p≥3 and p=2.

[0060] Step 5: Introduce the judgment of false echo occurrence scenarios. By converting the polar coordinate information composed of azimuth and distance in the initial target information matrix and the fixed strong reflectors into rectangular coordinates, and judging whether the distances between targets and between targets and strong reflectors are approximately equal, the false echo occurrence scenario is determined, whether the conditions for false echo occurrence are met, and the target information matrix is ​​updated. Step 5 includes the following steps:

[0061] Step 51: Initialize the target information matrix Ω point The polar coordinate information consisting of orientation and distance is converted into rectangular coordinates; the formula for converting polar coordinates to rectangular coordinates is:

[0062]

[0063] Step 52: Traverse matrix Ω point The orientation information θ in the first column pn Distance information ρ in the second column pn Then, substitute these values ​​into the formula for converting polar coordinates to rectangular coordinates to obtain the corresponding x and y coordinate values, and save them to the point target rectangular coordinate matrix Ω. prc In the middle, it is:

[0064]

[0065] Step 53: Simplify the fixed strong reflectors in the environment into a straight line form, as follows:

[0066] Ax fix +By fix +C=0 (8);

[0067] Among them, (y fix ,x fixThe symbol () represents the point through which the fixed reflector passes. The width of the fixed strong reflector is also stored, denoted as d.

[0068] Step 54: Traverse matrix Ω fp1 The orientation information θ in the first column pn Distance information ρ in the second column pn Substitute these values ​​into the simplified linear equation obtained from the fixed strong reflector to obtain the corresponding x and y coordinates, which are then saved to the point target rectangular coordinate matrix Ω. fprc0 In the following text:

[0069]

[0070] Step 55: Traverse matrix Ω fprc0 For each group of suspected false echoes, the straight-line distance l between the first two targets needs to be calculated. pp The specific calculation method is as follows:

[0071]

[0072] In the formula, i corresponds to matrix Ω prc The i-th target in the signal is also the first target in the suspected false echo group, and i∈[1,+∞).

[0073] Step 56: Using the i-th target (x) pi ,y pi () is the center of the circle, and the distance is l. pp By drawing a circle with radius r, we obtain the formula for the discriminant circle of a reflector:

[0074] (xx pi ) 2 +(yy pi ) 2 =l pp 2 (11);

[0075] Introducing the first conditional formula For matrix Ω prc The point target (x) that satisfies the first condition formula n ,y n ) to perform filtering;

[0076] For a point target that satisfies the first conditional formula, according to matrix Ω prc The target label information in the Ω is called. extend Given the target's azimuth and range information, calculate the azimuth difference Δθ. n =θ rightn -θ leftn and distance difference Δρ n =ρ upn -ρdownn ;Simplify the point target into a (x n ,y n The rectangular extended target with centroid Δθ has a length and width of Δθ. n and Δρ n ;

[0077] Substitute the points occupied by the extended target into the formula for the reflector discrimination circle. If the conditions of the formula are met, it proves that a moving reflector exists; otherwise, no reflector exists.

[0078] Step 57: Calculate the i-th target (x) pi ,y pi Distance to a fixed strong reflector:

[0079]

[0080] Where i corresponds to matrix Ω prc The i-th target in the list, where i ∈ [1, +∞);

[0081] Step 58: Introduce the second judgment condition formula l pl ≤l pp ≤l pl +d, for those satisfying the second condition formula, proves the existence of a fixed strong reflector; otherwise, no reflector exists.

[0082] Step 59: For suspected false echoes that do not meet the requirements of steps 56 and 58, process the first target (x) of the suspected false echo group. pi ,y pi ), call Ω extend The distance information of the i-th target in the middle is used to calculate the distance difference Δρ. i If l is satisfied pp ≤Δρ i If so, then sea surface reflection exists; otherwise, sea surface reflection does not exist.

[0083] For matrix Ω fprc0 If the target information in steps 56, 58, and 59 is not satisfied, then it is not a false echo, and the matrix Ω is updated. fprc0 Ω fprc1 Ω fprc1 Only save target information that meets the criteria.

[0084]

[0085] Step 6: Extract echo intensity information from the latest target information matrix and determine whether the new target information matrix conforms to the intensity information characteristics of false echoes. Delete target information in the new target information matrix that does not conform to the false echo intensity characteristics, and retain target information that does conform. Simultaneously, update the initial target information matrix to the false echo target information matrix. Step 6 also includes the following steps:

[0086] Step 61: Based on the group label information, i.e., the group number, traverse the matrix Ω by group. fprc1 The echo intensity information is used; a judgment formula is introduced for the intensity information of each group of suspected false echoes:

[0087] s p(i+1) ≤s pi (14);

[0088] Where i corresponds to the i-th target in each group of suspected false echoes, and i∈[1,+∞);

[0089] Step 62: Delete the first target information in each group of suspected false echoes and update matrix Ω. fprc1 Ω fprc Matrix Ω fprcd This is the false echo target feature information matrix:

[0090]

[0091] Step 7: Based on the information in the false echo target information matrix, set the suppression threshold for the digital domain of the radar echo data to suppress false echoes in a single frame of target information. Step 7 also includes the following steps:

[0092] Step 71: Based on the false echo target feature information matrix Ω fprcd Target label information, traverse and search matrix Ω extend Target feature information with the same target label information is stored as a false echo extended target feature information matrix Ω. fextend :

[0093]

[0094] Step 72: Returning to the radar data, the raw data is stored as a separate matrix D. Since each video sample is a 16-bit binary number, occupying 2 bytes of space, but only 1 byte is read at a time when reading the raw data, the raw data matrix D is:

[0095]

[0096] In the i-th row, every two data points form a video sampling data set;

[0097] Step 73: Radar video images are processed based on pixels; a Bitmap object is used to display the bitmap, and the LockBits and UnlockBits methods are called to lock and unlock the bitmap pixels in system memory, respectively; a matrix G is defined to store the intensity information of each pixel, as follows:

[0098]

[0099] Among them, g (i,j) Let g represent the pixel intensity of the j-th range resolution unit in the i-th azimuth resolution unit, and g (i,j) ∈[0,255].

[0100] 10. A method for identifying and suppressing false echoes from marine radar under calm sea surfaces according to claim 9, characterized in that the value of the pixel intensity can be obtained by performing bit operations, shifting, and other processing on the original radar data, the processing procedure being as follows:

[0101] g (i,j) =((d) (i,2j) <<8|d (i,2j-1) )&3FFF)>>6 (19);

[0102] Where 3FFF is a hexadecimal number;

[0103] After the above processing, the pixel intensity of the target or object in matrix G is taken as g. (i,j) ∈(100,255], for the case without a target, the pixel intensity is g. (i,j) ∈[0,55);

[0104] According to matrix Ω fextend Minimum azimuth θ leftn Maximum azimuth θ rightn The nearest distance ρ to the distance information downn The furthest distance ρ upn The constraints for extracting false echoes are set as follows:

[0105]

[0106] By extracting the constraints of false echoes, the azimuth and range information in the radar data matrix that meet the conditions are selected and used as the data objects for false echo suppression processing.

[0107] Again, using the constraint condition for extracting false echoes, process matrix G, and extract g elements from matrix G that meet the constraint condition. (i,j) Set all to g (i,j) =54, update matrix G to G new Then, call the Bitmap object again to display the new bitmap file.

[0108] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. In the above embodiments of the present invention, the descriptions of each embodiment have their own emphasis; parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments. It should be understood that the disclosed technical content in the several embodiments provided in this application can be implemented in other ways.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calm sea false echo identification and suppression for marine navigation radars, characterized in that, Includes the following steps: Step 1: For a single-frame radar image, based on the accumulation of multi-pulse echoes from the radar target, data is read from each range cell along the azimuth dimension, and the range and azimuth information at the time of appearance and disappearance of the extended target are saved respectively to obtain the information matrix of the extended target; Step 2: Convert the extended target information matrix into point coordinate information, that is, retain the echo crest position, extract the azimuth feature information and distance feature information of the crest position, and add the echo intensity feature information of the target, and store it as the initial target information matrix; Step 3: Extract the first column of azimuth feature information from the initial target information matrix and make a judgment. Determine the azimuth feature information, save the target information that matches the false echo azimuth feature, and update the target information matrix. Step 4: Extract the distance feature information from the second column of the initial target information matrix and perform discrimination to determine the distance feature information. Save the target information that matches the false echo distance feature and update the target information matrix; in step 4, according to the matrix... The group number column information and the group traversal distance information are included. ;for The Middle Distance information of each target Calculate their relative distance ; For the suspected false echo group, the first One target, based on the matrix Target label information and distance information Call and The Middle The nearest distance to each target information Longest distance Substitute the above parameters into the orientation condition relationship. In the middle, determine whether the conditions are met; for the suspected false echo group, the first... One goal, Time and The same principle applies at other times; Step 5: Introduce the judgment of false echo occurrence scenarios. By converting the polar coordinate information composed of azimuth and distance in the initial target information matrix and the fixed strong reflectors into rectangular coordinates, and judging whether the distances between targets and between targets and strong reflectors are approximately equal, it is determined whether the false echo occurrence scenario meets the conditions for false echo occurrence, and the target information matrix is ​​updated. Step 5 includes the following steps: Step 51: Initial target information matrix The polar coordinate information consisting of orientation and distance is converted into rectangular coordinates; the formula for converting polar coordinates to rectangular coordinates is: （6）； Step 52: Traverse the matrix The first column contains the location information. Distance information in the second column Then, substituting these values ​​into the formulas for converting polar coordinates to rectangular coordinates, we obtain the corresponding... coordinate values ​​and The coordinate values ​​are then saved to the point target's rectangular coordinate matrix. In the middle, it is: （7）； Step 53: Simplify the fixed strong reflectors in the environment into a straight line form, as follows: （8）； in, This represents the point through which the fixed reflector passes; simultaneously, it stores the width of the fixed strong reflector, denoted as . ; Step 54: Traverse the matrix The first column contains the location information. Distance information in the second column Substituting these values ​​into the simplified linear equation obtained from a fixed strong reflector, we get the corresponding... coordinate values ​​and The coordinate values ​​are then saved to the point target's rectangular coordinate matrix. In the following text: （9）； Step 55: Traverse the matrix For each group of suspected false echoes, the straight-line distance between the first two targets needs to be calculated. The specific calculation method is as follows: （10）； In the formula, Corresponding matrix The first in The first target, and also the first target in the suspected false echo group, and ; Step 56: Using the first One goal Centered on, distance By drawing a circle with radius r, we obtain the formula for the discriminant circle of a reflector: （11）； Introducing the first conditional formula For the matrix Point targets that satisfy the first condition formula Perform the screening; For a point target that satisfies the first conditional formula, according to the matrix... The target label information in the middle, calling and Use the target's azimuth and distance information to calculate the azimuth difference. and distance difference ;Simplify point targets into The target is a rectangular shape with the center of gravity, and its length and width are respectively... and ; Substitute the points occupied by the extended target into the formula for the reflector discrimination circle. If the conditions of the formula are met, it proves that a moving reflector exists; otherwise, no reflector exists. Step 57: Calculate the first... One goal Distance to a fixed strong reflector: （12）； in, Corresponding matrix The first in One goal, and ; Step 58: Introduce the second judgment condition formula For those that satisfy the second condition formula, it proves that a fixed strong reflector exists; otherwise, no reflector exists. Step 59: For suspected false echoes that do not meet the requirements of steps 56 and 58, process the first target of the suspected false echo group. , call The corresponding number in Distance information of each target, calculate the distance difference. If satisfied If so, then sea surface reflection exists; otherwise, sea surface reflection does not exist. For matrix If the target information in steps 56, 58, and 59 is not satisfied, then it is not a false echo, and the matrix is ​​updated. for , Only save target information that meets the criteria; （13）； Step 6: Extract echo intensity information from the latest target information matrix and determine whether the new target information matrix conforms to the intensity information characteristics of false echoes. Delete target information in the new target information matrix that does not conform to the echo intensity characteristics of false echoes, and retain target information that conforms to the characteristics in the new target information matrix; at the same time, update the initial target information matrix to the false echo target information matrix. Step 7: Based on the information in the false echo target information matrix, set the suppression threshold of the radar echo data digital domain to suppress false echoes in single-frame target information.

2. The method for identifying and suppressing false echoes from marine radar under calm sea surfaces according to claim 1, characterized in that, In step 1, the first step is performed sequentially along the orientation dimension. The first azimuth resolution unit Each range resolution unit is used to acquire extended target information and store the minimum azimuth of the extended target location information. Maximum direction The nearest distance to the distance information Longest distance To expand the target information matrix ,for: （1）； in, , ; The label representing the target, i.e., the number, and ,and .

3. The method for identifying and suppressing false echoes from marine radar under calm sea surfaces according to claim 1, characterized in that, Step 2 also includes the following steps: Step 21: Convert the expanded target into a point target; For the azimuth information, the difference between the first and second columns of the data matrix (1) is calculated and denoted as . ,Right now Then calculate the difference. Taking the median and rounding down, we get ; For distance information, the difference between the third and fourth columns of the data matrix (1) is calculated and denoted as... ,Right now Then calculate the difference. Taking the median and rounding down, we get ; The processed azimuth and distance information are combined into new polar coordinate information, which is the polar coordinate information of the point target, denoted as . ; Step 22: Use Representing echo intensity, then echo intensity The calculation formula is: （2）； In the formula, This represents the rightmost pixel of the target. This represents the leftmost pixel of the target. Indicates the farthest distance from the target. This indicates the nearest distance to the target; thus, the echo intensity value is obtained, which is the number of resolution cells occupied by the target echo. Step 23: Update the initial target information matrix based on the polar coordinates of the point target. ,for: （3）； in, The label of the target, i.e., the number, and ,and .

4. The method for identifying and suppressing false echoes from marine radar under calm sea surfaces according to claim 1, characterized in that, Step 3 also includes the following steps: Step 31: Traverse Location information ;for The Middle Location information of each target Determine the target and The Middle The minimum azimuth of the target's azimuth information Maximum direction Do they meet the orientation conditions? ; Step 32: For Target information that meets the orientation conditions is saved to a new matrix. In this context, it is defined as the target information matrix for azimuth determination, and in... Add suspected false echo group labeling information to the data, as follows: （4）； in, This indicates the target number that meets the orientation requirements. The group number indicates the group label information of suspected false echoes, and... ; Step 33: For If the target information does not meet the orientation conditions, it will be ignored.

5. The method for identifying and suppressing false echoes from marine radar under calm sea surfaces according to claim 1, characterized in that, Step 4 also includes the following steps: Step 41: For Target information that does not meet the distance criteria will be deleted directly. Step 42: Retain Detect target information that meets the distance condition and update the matrix. For the new matrix The updated matrix Defined as a distance-based target information matrix, as follows: （5）； in, This indicates the target number that meets the orientation requirements. The group number, indicating a suspected false echo, is obtained from the azimuth information, and... .

6. The method for identifying and suppressing false echoes from marine radar under calm sea surfaces according to claim 1, characterized in that, Step 6 also includes the following steps: Step 61: Traverse the matrix by grouping according to the grouping label information, i.e., the group number. The echo intensity information is used; a judgment formula is introduced for the intensity information of each group of suspected false echoes: （14）； in, Corresponding to each group of suspected false echoes One goal, and ; Step 62: Delete the first target information in each group of suspected false echoes and update the matrix. for ,matrix This is the false echo target feature information matrix: （15）。 7. The method for identifying and suppressing false echoes from marine radar under calm sea surfaces according to claim 1, characterized in that, Step 7 also includes the following steps: Step 71: Based on the false echo target feature information matrix Target label information, traverse and search the matrix Target feature information with the same target label information is saved as a false echo extended target feature information matrix. : （16）； Step 72: Regress to radar data; the raw data is stored as a separate matrix. Since each video sample data is a 16-bit binary number, occupying 2 bytes of space, but only 1 byte is read at a time when reading the raw data, the raw data matrix... for: （17）； Among them, the Each row consists of two data points forming one video sample. Step 73: Radar video images are processed based on pixels; a Bitmap object is used to display the bitmap, and the LockBits and UnlockBits methods are called to lock and unlock the bitmap pixels in system memory, respectively; a matrix is ​​defined. The intensity information of each pixel is saved as follows: （18）； in, Representing the On the first azimuth resolution unit The pixel intensity of each distance resolution unit, and .

8. The method for identifying and suppressing false echoes from marine radar under calm sea surfaces according to claim 7, characterized in that, The pixel intensity value can be obtained by performing bit operations, shifting, and other processing on the raw radar data. The processing procedure is as follows: （19）； in, It is a hexadecimal number; After the above processing, the matrix The pixel intensity value for the target or object is... For cases without a target, the pixel intensity value is... ; According to the matrix Minimum position Maximum direction The nearest distance to the distance information Longest distance The constraints for extracting false echoes are set as follows: （20）； By extracting the constraints of false echoes, the azimuth and range information in the radar data matrix that meet the conditions are selected and used as the data objects for false echo suppression processing. Again, using the constraints for extracting false echoes, the matrix is ​​processed. , matrix Those that meet the restrictions Set all to Update matrix for Then, call the Bitmap object again to display the new bitmap file.

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