Sea surface target stable handover and track tracking method and system based on navigation radar

Abstract

The invention provides a sea surface target stable handover and track tracking method and system based on a navigation radar. The method comprises the following steps: the navigation radar performs multi-target stable tracking by using sea surface target echoes; analyzing and screening, and appointing important targets which need to be focused; photoelectric tracking target parameters are calculated by utilizing a sea surface dynamic constraint equation or different-station deployment longitude and latitude conversion according to radar and photoelectric positions; and a photoelectric tracking target is guided, and the track of the target is dynamically and finely adjusted to realize stable tracking of a stable target image. Due to the fact that coordinates of targets measured by the radar are different, each datum cannot be converted to three-dimensional target tracking, and position conversion of the targets cannot be achieved. According to the method, under the condition that a sea surface target lacks measurement dimensions, mutual conversion between measurement coordinates can still be achieved by means of a constraint equation and longitude and latitude conversion, and rapid guide tracking of the target is stably achieved.

Description

Technical Field

[0001] The present invention relates to the technical fields of radar and optoelectronic data processing. Specifically, it relates to a method and system for stable handover and track tracking of sea surface targets based on a navigation radar. Background Art

[0002] As the maritime frontier, the offshore area is an important part of the barrier for safeguarding national security. The security and stability of the offshore and coastal areas are closely related to the fundamental interests of the country, the well-being of the people, and even the survival and development of the nation.

[0003] In addition, the increasing prosperity of various marine industries depends on the navigation of ships scattered across the sea. The safety of sea lanes is crucial for ships, and the maritime shipping fleet also occupies an important position in China's national defense reserve force. Research work related to the surveillance of maritime ship targets includes ship identification, positioning, classification, tracking, etc. This series of work plays a crucial role in fields such as sea traffic management, port ship scheduling, maritime ship search and rescue, and maritime navigation.

[0004] Since the detection target principle of the navigation radar is quite different from that of optoelectronics, the radar emits electromagnetic waves, measures the reflected waves of the target, measures the azimuth of the antenna when emitting and estimating the distance and receiving the echo. Its characteristics are that the measurement of sea surface targets is reliable and effective, and it is basically not affected by weather and night, but the measurement error is large. Low-cost navigation radars can measure long distances, but they do not have elevation angle information and can only locate the target on the sea surface. Since the sea surface changes every moment and belongs to a dynamic and wave-constrained plane, its model dynamics are very complex. When the waves are small, it is extremely complex and variable to process according to the dynamic manifold. Using average processing has a large error, and an average correction data processing method can be appropriately adopted. The advantage of optoelectronics is high image resolution and image display. As long as the algorithm and control are appropriate, continuous image tracking can be achieved. The main problems are the lack of distance information, a small field of view, easy loss of the target, and jitter problems. When there is no distance information, the method of cross-positioning with two optoelectronics can be used to calculate the target distance of each optoelectronic. Radar and optoelectronics are a relatively perfect combination, achieving fine tracking within rough tracking, a small field of view within a large field of view, and all-weather data and image sharing. It's just that the measurement coordinates of the two are the same only in terms of azimuth, and there are also significant differences in their accuracy and granularity. The two are organically combined using the method of guiding the small field of view with the large field of view.

[0005] Patent application document CN117148305A discloses a target tracking method and system for a radar for sea use. By receiving echo signals in real time and processing them, target point track information and track information are obtained; then, beam information required for tracking is calculated using the target azimuth, discrimination and switching of the pulse repetition frequency mode of the tracking beam are performed using the target distance, and a method for delaying boundary transition zone switching is designed. However, this patent cannot completely solve the existing technical problems and cannot meet the requirements of the present invention. Summary of the Invention

[0006] Aiming at the defects in the prior art, the purpose of the present invention is to provide a method and system for stable handover and track tracking of sea surface targets based on a navigation radar.

[0007] According to the method for stable handover and track tracking of sea surface targets based on a navigation radar provided by the present invention, it includes:

[0008] Step S1: Use a navigation radar to track sea surface targets, establish a mathematical model of the entire area and track movement, and achieve stable tracking of multiple targets;

[0009] Step S2: Analyze and screen preset targets according to the characteristics of the sea surface targets of concern, or fuse AIS target information to determine preset targets, or manually specify preset targets, and extract the track parameters of radar targets;

[0010] Step S3: Based on the sea surface dynamic equation, input the track parameters of the radar target, and solve the track parameters of the optoelectronic target;

[0011] Step S4: Adjust the optoelectronic tracking target coordinates or observation direction, continuously track the optoelectronic target, estimate the deviation between the target and the image center area, extract the target correction parameters, and finely adjust the optoelectronic observation direction based on the target correction parameters to keep the target always located at the image center;

[0012] Step S5: Feed back the target correction parameters to the radar target parameters, and apply the multiple statistical method to realize the automatic calibration of the errors of the radar and optoelectronic systems.

[0013] Preferably, according to the radar data characteristics and echo characteristics, its video image is in a circular ring shape, using the distance sampling point sequence in the azimuth angle as the echo input, and then adding the distance echo sequence in the azimuth, and continuously scanning in a 360-degree cycle;

[0014] If the radar operates in a one-week scanning mode in azimuth, the time T used for scanning one week, starting from the due north in the clockwise direction, the azimuth angle of the scanning antenna at time t The angular resolution of the circumference is Δ β , a total of resolution units are generated; in terms of distance, the distance resolution is Δ r, from the smallest blind area in terms of azimuth to the maximum operating range R of the radar max -R min , a total of resolution cells are generated, taking the integer value, and adding 1 if there is a decimal;

[0015] When the radar is at position (x0, y0) and a point (m β , n r ) on the scanned image area, where its value is within 0 ≤ m β ≤ M β , 0 ≤ n r ≤ N r , according to the geometric relationship of the projection, the horizontal position (x′, y′) of the near-sea target is calculated as follows:

[0016]

[0017]

[0018] where R max , R min represent the maximum and minimum distances detected by the radar respectively; M β represents the number of resolution cells in the azimuth of the radar target; N r represents the number of resolution cells in the distance of the radar target; the measurement error follows a normal distribution with a mean of zero and variances of

[0019] For a certain position (x 0t , y 0t ) on the plane, if only the position of the radar relative to the target is concerned, the covariance matrix of the measurement error of the rectangular coordinates of the measured target is:

[0020]

[0021] where:

[0022] Δx t , Δy t represent the measured and calculated values of the x and y channels relative to the radar position respectively; E represents the operation of taking the mean value; d represents the operation of taking the total differential, differentiating and expanding the error according to azimuth and distance; θ 0t represents the azimuth system error deviation angle; represent the calculated variances of the x and y channels respectively; σ ΔxΔy , σ ΔyΔx represent the calculated covariances of the x and y channels respectively; represents the distance measurement variance of the target; represents the azimuth measurement variance of the target;

[0023] The three-dimensional coordinates of the target relative to the center of the radar antenna are:

[0024]

[0025] where r t is the slant range from the radar to the target; ε t is the elevation angle of the target relative to the horizontal plane of the navigation radar, positive above and negative below; β t is the angle of the point of the target in the radar horizontal plane relative to the due north direction, positive clockwise; assume that each measurement channel follows Gaussian white noise with a mean of zero and a variance of ;

[0026] Covariance matrix of the measurement errors in Cartesian coordinates:

[0027]

[0028] σ xy σ xz σ yx , σ yz σ zx σ zy , respectively represent the calculated variances and covariances of the three Cartesian coordinates; represents the variance of the elevation angle;

[0029] where: is an orthogonal matrix;

[0030] The linear deviation of the angle error r t σ ε , r t cosε t σ β , as the distance increases, the influence on the left end becomes greater and greater; the left square matrix is a non-diagonal matrix, that is, there is a coupling phenomenon of errors in each component.

[0031] Preferably, a fixed optoelectronic sensor is set at a certain position (x 0t , y 0t ) on a plane at an altitude of h0, and the relative bow azimuth and horizontal elevation angle (ε t , β t ) of a certain target (x t ′, y t ′) are measured. The measurement errors follow a normal distribution with a mean of zero and variances of Its relative Cartesian coordinates with respect to the optoelectronics are:

[0032]

[0033] Covariance matrix of measurement errors in rectangular coordinates:

[0034]

[0035] σ Δx′Δy′ 、σ Δy′Δx′ 、 represent the calculated variances and covariances of the two rectangular coordinates of optoelectronics; h represents the altitude where the optoelectronic equipment is installed;

[0036] Where:

[0037] The three-dimensional coordinates of the target relative to the center of the optoelectronic antenna are:

[0038]

[0039] Among them, r t is the slant range from the optoelectronics to the target; ε t is the elevation angle of the target relative to the horizontal plane of the navigation radar, positive above and negative below; β t is the angle between the point of the target on the radar horizontal plane and the due north direction, positive clockwise.

[0040] Preferably, let the longitude and latitude of a certain target measured by AIS target, Beidou, and GPS on the ellipsoid surface be The measurement errors follow a normal distribution, with a mean of zero and variances of

[0041] The covariance matrix is: The cross-correlation between longitude and latitude is zero.

[0042] Preferably, the input of the mathematical models of the whole area and track movement is the target point traces of the navigation radar. Through forward and backward correlation and extrapolation filtering calculations, the movement parameters of the target are calculated. The output of the mathematical models of the whole area and track movement is the target track, the point traces with the target track number, and the output track is a two-dimensional sequence with the target number.

[0043] According to the sea surface target stable handover and track tracking system based on the navigation radar provided by the present invention, it includes:

[0044] Module M1: Use the navigation radar to track sea surface targets, establish mathematical models of the whole area and track movement, and achieve stable tracking of multiple targets;

[0045] Module M2: Analyze and screen preset targets according to the characteristics of the sea surface targets of concern, or fuse AIS target information to determine preset targets, or manually specify preset targets, and extract the track parameters of radar targets;

[0046] Module M3: Based on the dynamic equation of the sea surface, input the track parameters of the radar target, and solve the track parameters of the optoelectronic target;

[0047] Module M4: Adjust the optoelectronic tracking target coordinates or observation direction, continuously track the optoelectronic target, estimate the deviation between the target and the central region of the image, extract the target correction parameters, and finely adjust the optoelectronic observation direction based on the target correction parameters to keep the target always located at the center of the image;

[0048] Module M5: Feed back the target correction parameters to the radar target parameters, and apply the multiple statistical method to realize the automatic calibration of the radar and optoelectronic system errors.

[0049] Preferably, according to the radar data characteristics and echo characteristics, its video image is in a circular ring shape, using the distance sampling point sequence in the azimuth angle as the echo input, and then adding the distance echo sequence in the azimuth, and continuously scanning in a 360-degree cycle;

[0050] If the radar operates in a one-circle scanning mode in azimuth, the time T taken for one scan, starting from the due north in the clockwise direction, the azimuth angle of the scanning antenna at time t The angular resolution of the circumference is Δ β , a total of resolution units are generated; in terms of distance, the distance resolution is Δ r , from the smallest blind area in azimuth to the maximum operating distance R of the radar max -R min , a total of resolution units are generated, taking integers, and adding 1 if there is a decimal;

[0051] When the radar position is (x0, y0), and a certain point (m β , n r ) on the scanned image area, whose value is within 0 ≤ m β ≤ M β , 0 ≤ n r ≤ N r , according to the geometric relationship of the projection, the horizontal position (x′, y′) of the near-sea target represented is calculated as follows:

[0052]

[0053] Or

[0054] Among them, R max , R min respectively represent the maximum and minimum distances detected by the radar; M β represents the number of resolution units of the radar target azimuth; N r represents the number of resolution units of the radar target distance; the measurement error follows a normal distribution, with a mean of zero and variances of

[0055] For a certain position (x 0t , y 0t ) on a plane, if only the position of the radar relative to the target is concerned, the covariance matrix of the measurement error of the rectangular coordinates of the measured target is:

[0056]

[0057] Where:

[0058] Δx t , Δy t respectively represent the measured and calculated values of the x and y channels relative to the radar position; E represents the operation of taking the mean value; d represents the operation of taking the total differential, and taking the derivative and expanding the error according to the azimuth and distance; θ 0t represents the deviation angle of the azimuth system error; respectively represent the calculated variances of the x and y channels; σ ΔxΔy , σ ΔyΔx respectively represent the calculated covariances of the x and y channels; represents the variance of the distance measurement of the target; represents the variance of the azimuth measurement of the target;

[0059] Relative to the center of the radar antenna, the three-dimensional coordinates of the target are:

[0060]

[0061] Where, r t is the slant range from the radar to the target; ε t is the elevation angle of the target relative to the horizontal plane of the navigation radar, positive above and negative below; β t is the angle between the point of the target on the radar horizontal plane and the due north direction, positive clockwise; Assume that each measurement channel follows Gaussian white noise with a mean of zero and a variance of ;

[0062] Covariance matrix of the measurement error of rectangular coordinates:

[0063]

[0064] σ xy , σ xz , σ yx , σ yz , σ zx , σ zy , respectively represent the calculated variances and covariances of the rectangular three-coordinates; represents the variance of the elevation angle;

[0065] Where: is an orthogonal matrix;

[0066] The linear deviation r of the angular error t σ ε , r t cosε t σ β , as the distance increases, the influence on the left end becomes greater and greater; the left-end square matrix is a non-diagonal matrix, that is, there is a coupling phenomenon of errors in each component.

[0067] Preferably, a photoelectric sensor is fixed at a certain position (x 0t , y 0t ) on a plane at a position with an altitude of h0, and the relative bow azimuth and horizontal elevation angle (ε t ′, y t ′) of a certain target (x t , β t ) are measured. The measurement errors follow a normal distribution with a mean of zero and variances of Its rectangular coordinates relative to the photoelectric are:

[0068]

[0069] The covariance matrix of the measurement errors of the rectangular coordinates:

[0070]

[0071] σ Δx′Δy′ 、σ Δy′Δx′ 、 represent the calculated variances and covariances of the two rectangular coordinates of the photoelectric; h represents the altitude at which the optoelectronic device is installed;

[0072] Among them:

[0073] The three-dimensional coordinates of the target relative to the center of the optoelectronic antenna are:

[0074]

[0075] Among them, r t is the slant range from the optoelectronic to the target; ε t is the elevation angle of the target relative to the horizontal plane of the navigation radar, positive above and negative below; β t is the angle between the point of the target on the radar horizontal plane and the due north direction, positive clockwise.

[0076] Preferably, the longitude and latitude of a certain target measured by the AIS target, Beidou, and GPS on the ellipsoid surface are The measurement errors follow a normal distribution with a mean of zero and variances of

[0077] The covariance matrix is as follows: The cross-correlation between longitude and latitude is zero.

[0078] Preferably, the input of the mathematical models of the full-region and track motion is the target point traces of the navigation radar. Through forward and backward correlation and extrapolation filtering calculations, the motion parameters of the target are calculated. The outputs of the mathematical models of the full-region and track motion are the target tracks, the point traces with target track numbers, and the output tracks are two-dimensional sequences with target numbers.

[0079] Compared with the prior art, the present invention has the following beneficial effects:

[0080] 1. By combining the spherical target characteristics of the navigation radar through the spherical constraint equation, the present invention realizes the conversion from two-dimensional coordinates to three-dimensional coordinates, and then through the conversion of the rectangular coordinates of the sphere center to the pointing coordinates of the optoelectronic image center, and can solve the target distance of the optoelectronic. The conversion error is one order of magnitude smaller than other methods, with high efficiency, and good system economy and practicability;

[0081] 2. According to the target performance of the navigation radar and the target characteristics of the optoelectronic, the present invention realizes the measurement coordinate conversion based on the ellipsoidal surface constraint, solves the problem of coordinate conversion, and can be extended in many ways. For example, low-altitude unmanned aerial vehicles and large ships can be tracked above the center of the optoelectronic; multiple stations can be guided to simultaneously realize optoelectronic target tracking; multi-station optoelectronics can realize image fusion; optoelectronic targets can guide radar targets, etc.;

[0082] 3. After preliminary verification, the present invention has been improved many times, and the implemented modules are applied in the multi-source joint perception system, achieving good effects of dynamic target detection and static target detection guided by the radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objects and advantages of the present invention will become more apparent:

[0084] Figure 1 is the system flow chart of the present invention;

[0085] Figure 2 is the fishing ground map of radar strong clutter area guiding optoelectronic tracking operation;

[0086] Figure 3 is the map of radar guiding optoelectronic to track a small red boat;

[0087] Figure 4 is the map of radar guiding optoelectronic to track a small cargo ship;

[0088] Figure 5 is the map of radar guiding optoelectronic to track a beacon;

[0089] Figure 6 It is a diagram of a radar-guided optoelectronic tracking fishing boat. Specific implementation manners

[0090] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all belong to the protection scope of the present invention.

[0091] Embodiment 1

[0092] An embodiment of the present invention discloses a method and system implementation for moving target detection in a strong sea clutter environment, as Figure 1 shown, including:

[0093] Utilize a navigation radar and optoelectronics to jointly detect and track sea targets, achieve mutual guidance and fusion of targets in the case of incomplete information, achieve rapid evidence collection and authentication of illegal sea targets, organize effective countermeasures, and have very important functions and significance for border defense and anti-smuggling, etc.

[0094] Mainly introduce the specific steps:

[0095] 1) Target conversion from geodetic coordinates to geocentric rectangular coordinates

[0096]

[0097] The above formula can be expressed as:

[0098]

[0099] where a, b, h i are respectively the semi-major axis, semi-minor axis, and altitude of the earth ellipsoid. The targets at each station and any point on the ellipsoid surface and in space can be calculated in this way.

[0100] Radius of curvature of the prime vertical: According to the 2000 China Geodetic Coordinate System (CGCS2000), a is the semi-major axis of the earth, and the eccentricity a = 6378137m, b = 6356752.314m, e = 0.0818191913087; the elliptic flattening

[0101] 2) Conversion from geocentric rectangular coordinates to geodetic coordinates Conversion

[0102]

[0103] As can be seen from the above formula, iterative calculations are required in the conversion of the target position at a certain altitude into latitude information.

[0104] When the altitude is zero, the target is on the ellipsoid surface.

[0105] 3) Constraint equation of the ellipsoid surface

[0106] Substitute the longitude, latitude, and altitude of the radar station site and the target measurement coordinates (r t , ε t , β t ) of the sensor into the above formula to calculate the position of h t = 0 on the ellipsoid surface:

[0107]

[0108] If the measured target has an altitude on the ellipsoid surface, the following relationship holds:

[0109] If h t > 0, then the constraint equation of the ellipsoid surface is:

[0110]

[0111] If h t = 0, then the constraint equation of the ellipsoid surface is:

[0112]

[0113] For radar, it can measure the azimuth and distance of the target. Using the above constraint relationship on the ellipsoid surface, after complex simplification and considering the case where the distance is less than 100 km, the ellipsoid surface is simplified to an equivalent spherical surface, and a quadratic equation of one variable for the distance can be obtained. The constraint equation of the spherical target is:

[0114] r t 2 + 2(h0 + N0)r t sin ε t + h0(h0 + 2N0) ≈ 0

[0115] The above formula also has constraints on optoelectronics. That is, given the elevation angle of the target, the distance from the optoelectronics to the spherical target can be estimated. However, when calculating the parameters in the equation, they need to be calculated according to the longitude, latitude, and altitude of the optoelectronics.

[0116] Given the target distance, the elevation angle can be obtained:

[0117]

[0118] For radar station 1, the elevation angle of the target can be solved and substituted into the following formula to obtain:

[0119]

[0120] Among them, the subscript 1 represents the measured or calculated value from Radar Station 1. The parameter can be substituted into the three-dimensional error covariance matrix to approximately obtain the variance of the rectangular coordinates.

[0121] 4) Transfer from the geocentric rectangular coordinate system to the rectangular coordinates of Optoelectronic Station 2

[0122] For convenience, the radar station is 01 and the optoelectronic station is 02. The longitude, latitude, and altitude of each station site (which can be measured by Beidou or GPS) are known; the target measurement coordinates of the sensors at the two station sites are converted into the ellipsoidal rectangular coordinate system. The radar measures the same batch of targets, and the geocentric rectangular representation of the targets is consistent:

[0123]

[0124] The target rectangular coordinates of Optoelectronic Station 02 can be obtained:

[0125]

[0126] Since the 3×3 matrix in the above formula is an orthogonal matrix, the matrix inverse is the matrix transpose. The above formula can be further simplified.

[0127] If the radar and optoelectronics are on the same iron tower and their altitudes are similar, the first term in the big brackets of the above formula is zero.

[0128] The target rectangular coordinates of the optoelectronic station have been obtained, and then the elevation angle and azimuth of the optoelectronic observation target are calculated:

[0129]

[0130] or

[0131] Calculate the distance, azimuth, and elevation angle of the next target relative to the infrared tracking and aiming system according to the extrapolated value;

[0132]

[0133] Among them, the elevation angle ε t2 is negative, when 0 > ε max ≥ ε t2 > -90°, near ε max it is necessary to judge according to the maximum distance.

[0134] The optoelectronics tracks the target as the target center according to the calculated azimuth and elevation angle of the target.

[0135] Comprehensive judgment of the target to be concerned about: When a superior designates a certain radar target, it is an important target to be concerned about; when the track of a certain radar target comes from a special sea area or a sensitive area, it needs to be concerned about, and optoelectronic tracking and judgment should be mobilized; when the AIS information of the target appears abnormal (changing numbers, changing signs, stopping and starting from time to time, etc.), optoelectronic tracking and image evidence collection should be mobilized; when there are special situations in the track of a certain target, such as docking, drawing circles, staying for a long time, etc., optoelectronic tracking and image evidence collection also need to be mobilized. According to the needs of different industries, there are many different experiences and special processes for judgment to determine important targets to be concerned about.

[0136] When a certain target is focused on and determined for optoelectronic image tracking, a request will be sent to the display and control system to estimate the central coordinates (elevation angle and azimuth) of the target in the optoelectronic system. Mobilize the optoelectronic device to quickly turn to the target position, search and fine-tune the target to always be near the center within a certain frame, and realize the optoelectronic tracking of the moving target.

[0137] The measurement coordinate expansion of two sensor measurement stations under spherical constraint conditions, and the basic principle of target transformation. Derive the spherical constraint equation based on ellipsoidal coordinates, and give the calculation and processing conversion process for estimating the new coordinates. The mutual conversion between the coordinates of the two-station (incomplete) measurement target under the ellipsoidal surface constraint is realized. The problems brought by incomplete measurement are compensated.

[0138] During the optoelectronic target tracking process, the optoelectronic center should always be aligned with the moving target (near the center). It can be adjusted by adjusting the optoelectronic interface. Due to calculation errors, (constraint equation) model errors, conversion errors, sea level tides, system deviations of the two sensors, target measurement errors, station location errors, etc. during the conversion process, these need to be systematically analyzed. Statistically analyze the deviation between the target image center and the optoelectronic center, analyze the magnitude of the deviation sequence, and determine which factors play a major role, and further adjust the system error. It is also possible to directly fine-tune the optoelectronic image center to always place the target center at the image center. This is because different systems have different main factors and need to be systematically analyzed for necessary compensation.

[0139] Such as Figure 1 shown, the composition of the navigation radar-guided optoelectronic system, the relationship between each module and the information transmission process.

[0140] Such as Figure 2 shown, the detection of small wooden boats with strong clutter non-coherent moving targets in the aquaculture area (the left figure is the radar image, the upper right figure is the optoelectronic image, and the lower right figure is the infrared image). It can be seen that there is optoelectronic tracking of multiple small boat tracks in and around the aquaculture area.

[0141] Such as Figure 3 shown, in the display and control system, it can be seen that the radar target is labeled, including various tracks. Clicking on "concern" can directly realize the process of guiding the optoelectronics. The optoelectronics can stably track the small boat, and its tracking is very effective.

[0142] As Figure 4 shown, in the display and control system, a radar target board can be seen, which contains multiple tracks. Clicking on "Follow" directly realizes the process of guiding the optoelectronic device. The optoelectronic device can stably track a small cargo ship, and its tracking is very stable.

[0143] As Figure 5 shown, in the display and control system, a radar target board can be seen, which contains multiple tracks. Clicking on "Follow" directly realizes the process of guiding the optoelectronic device. The optoelectronic device can stably track a beacon, and its tracking is very stable.

[0144] As Figure 6 shown, in the display and control system, a radar target board can be seen, which contains multiple tracks. Clicking on "Follow" directly realizes the process of guiding the optoelectronic device. The optoelectronic device can stably track a relatively large fishing boat, and its tracking is very stable and effective.

[0145] Implementation process and improvement methods:

[0146] First, according to the incomplete measurement characteristics of the navigation radar and the optoelectronic system, and based on the characteristics of marine targets, combined with the ellipsoidal constraint equation, the present invention realizes the three-dimensional tracking of sea-level targets and achieves good results. During the R & D process, the improvement methods are as follows: 1) Focus on improving the calculation method of the constraint equation parameters and adopt high-precision calculation of the ellipsoidal parameters; 2) Correct the ellipsoidal parameters according to the data of sea-level rise or fall; 3) Analyze the calculation process, optimize the key links, and improve the algorithm module; 4) Continuously improve the statistical and correction process to achieve the effects of stable and accurate guidance and fast and stable tracking. 5) Its new applications are still in the debugging of new (guiding multiple optoelectronics, large-scale networking, etc.) systems. Many small problems are also found in the actual test, and the software module is also modified and improved accordingly. Judging from the actual test results, this method is effective.

[0147] Embodiment 2

[0148] The present invention is used for the navigation radar to guide the optoelectronic system to realize effective tracking of sea targets, which plays an extremely important role in aspects such as rapid detection, image evidence collection and recognition of illegal sea targets. The implementation principle and improvement methods are given, and the implementation process of the system is described in detail and the problems are discussed. After preliminary verification, the method is improved many times. The implemented module is applied in the multi-source joint perception system, achieving fast, stable and reliable tracking effects, and greatly improving the detection, tracking and evidence collection capabilities of various illegal targets. Specifically, it includes the following modules:

[0149] Module M1: Navigation Radar Sea Target Detection and Tracking Module: It adopts the sea target detection and tracking software module. Since the navigation radar is a two-dimensional radar, it has high efficiency and reliability in scanning sea targets, but low economy, and its performance-price ratio is the best. Detecting and tracking radar targets on the sea has important engineering application significance. The detection and tracking module adopts ES3.0 (see the company's invention patent), achieving advanced sea clutter suppression and small target detection and tracking capabilities. The application module has strong track persistence ability for sea targets, suppresses various sea clutter interferences, and enhances the small target detection ability. Using the navigation radar to track sea targets, establishing mathematical models of the entire area and track movement, and achieving stable tracking of multiple targets;

[0150] Module M2: Important Target Screening Module: Analyze and screen important targets based on the characteristics of the concerned sea targets, referring to the sea area where the target appears, its origin and destination, time and sea area, sea conditions and weather, historical information, draft depth, track (such as detour, curve, speed, stay, movement, etc.) characteristics. It is necessary to comprehensively judge the above information of the target according to specific user requirements, and it can also include multi-sensor target fusion track information, or AIS target (illegal target) information determination, or (by the commander) manually specifying important targets, separating the target tracks that need to be focused on and further identified, authenticated, and evidenced, and extracting important sea targets and target track parameters; send them to the coordinate calculation module through the display and control system;

[0151] Module M3: Coordinate Calculation and Optoelectronic Center Pointing Parameter Calculation Module: According to the longitude, latitude and altitude of the radar station site, and based on the constraint equation of the ellipsoidal surface target, calculate the elevation angle information of the radar target, obtain the three-dimensional coordinates of the target, and through the coordinate rotation and translation transformation of the ellipsoidal surface (remote or local), obtain the pointing center of the optoelectronic system. The pointing information guides the optoelectronic system to track the target.

[0152] Module M4: Fine Tuning and Calibration Module: Statistically analyze the error sequence between the weighted center and the actual image center of the target image, automatically adjust the weighted center to the image center step by step, or manually adjust the image center by moving the up, down, left, and right keys to make the two centers basically coincide. Since different systems have different error models, analyze the main factors of the error sequence and perform necessary system error compensation.

[0153] Those skilled in the art know that, in addition to implementing the systems, devices and their respective modules provided by the present invention in the form of pure computer-readable program codes, the method steps can be logically programmed to enable the systems, devices and their respective modules provided by the present invention to be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, embedded microcontrollers, etc. to achieve the same program. Therefore, the systems, devices and their respective modules provided by the present invention can be considered as a kind of hardware components, and the modules included therein for implementing various programs can also be regarded as the structures within the hardware components; the modules for implementing various functions can also be regarded as either software programs for implementing the methods or the structures within the hardware components.

[0154] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A method for stable handover and track tracking of sea surface targets based on navigation radar, characterized in that: include: Step S1: Using navigation radar to track sea surface targets, establishing a mathematical model of the entire area and track motion, and achieving stable tracking of multiple targets; Step S2: Analyze and select preset targets according to the characteristics of the sea surface targets of interest, or determine preset targets by integrating AIS target information, or manually specify preset targets, and extract track parameters of radar targets; Step S3: Based on the sea surface dynamic equation, the track parameters of the radar target are input and the track parameters of the optoelectronic target are solved; Step S4: adjusting the coordinates or observation direction of the optoelectronic tracking target, continuously tracking the optoelectronic target, estimating the deviation between the target and the central area of ​​the image, extracting the target correction parameter, and fine-tuning the optoelectronic observation direction based on the target correction parameter so that the target is always located in the center of the image; Step S5: Feedback the target correction parameters to the radar target parameters, and apply multiple statistical methods to achieve automatic calibration of radar and optoelectronic system errors.

2. The method for stable sea surface target handover and track tracking based on navigation radar according to claim 1 is characterized in that: According to the characteristics of radar data and echo, the video image is in the shape of a ring, with the distance sampling point sequence in azimuth angle as the echo input, and then the distance echo sequence in azimuth is added, and the scanning is carried out in a 360-degree cycle; If the radar is working in the azimuth scanning mode, the time taken for one scan is T, starting from the north clockwise, the azimuth of the scanning antenna at time t is The angular resolution of the circle is Δ β , a total of resolution units; in terms of distance, the distance resolution is Δ r , from the smallest blind spot in azimuth to the maximum range of the radar R max -R min , a total of Resolution units, take the integer, if there is a decimal, add 1; When the radar position is (x0, y0), a point (m β ,n r ), whose value is 0≤m β ≤M β ,0≤n r ≤N r According to the geometric relationship of the projection, the horizontal position (x′, y′) of the close-range target on the sea surface represented is calculated as follows: Among them, R max , R min Respectively represent the maximum and minimum distances detected by the radar; M β The number of resolution units representing the radar target azimuth; N r The number of resolution units representing the radar target distance; the measurement error follows a normal distribution with a mean of zero and variances of For a certain position (x 0t ,y 0t ), if we only care about the position of the radar relative to the target, the covariance matrix of the measurement error of the rectangular coordinates of the target is: Δx t , Δy t They represent the x and y channel measurement calculation values ​​relative to the radar position respectively; E represents the operation of taking the average; d represents the total differential operation, taking the derivative and error expansion according to the azimuth and distance; θ 0t Indicates the azimuth system error declination; Respectively represent the variance of x and y channels; σ ΔxΔy , σ ΔyΔx Respectively represent the covariance calculation of x and y channels; represents the distance measurement variance of the target; represents the target's position measurement variance; Relative to the center of the radar antenna, the three-dimensional coordinates of the target are: Among them, r t is the slant distance from the radar to the target; t is the elevation angle of the target relative to the horizontal plane of the navigation radar, which is positive when it is above and negative when it is below; β t is the angle between the target point on the radar horizontal plane and the true north direction, clockwise is positive; assume that each measurement channel has a mean of zero and a variance of Gaussian white noise; Covariance matrix of measurement errors in rectangular coordinates: σ xy , σ xz , σ yx , σ yz , σ zx , σ zy , Respectively represent the calculated variance and covariance of the three rectangular coordinates; represents the variance of the elevation angle; Linear deviation of angular error r t σ ε ,r t cosε t σ β , as the distance increases, the impact on the left end becomes greater and greater; the square matrix on the left end is a non-diagonal matrix, that is, there is a coupling phenomenon of errors in each component.

3. The method for stable sea surface target handover and track tracking based on navigation radar according to claim 2 is characterized in that: A certain position on the plane (x 0t ,y 0t ) A fixed photoelectric sensor at an altitude of h0 measures a target (x t ′,y t ′) and the relative bow azimuth and horizontal elevation angle (ε t ,β t ), the measurement error follows a normal distribution with a mean of zero and variances of Its rectangular coordinates relative to the photoelectric are: Covariance matrix of measurement errors in rectangular coordinates: σ Δx′Δy′ , σ Δy′Δx′ , represents the calculated variance and covariance of the rectangular two-coordinate of the photoelectric device; h represents the altitude at which the photoelectric device is installed; Relative to the center of the photoelectric antenna, the three-dimensional coordinates of the target are: Among them, r t is the slant distance from the photoelectric to the target; ε t is the elevation angle of the target relative to the horizontal plane of the navigation radar, which is positive when it is above and negative when it is below; β t The angle between the target point on the radar horizontal plane and the true north direction, clockwise is positive.

4. The method for stable sea surface target handover and track tracking based on navigation radar according to claim 3 is characterized in that: Assume that the longitude and latitude of a target measured by AIS target, Beidou and GPS on the ellipsoid surface are The measurement errors follow a normal distribution with a mean of zero and variances of The covariance matrix is: The latitude and longitude cross correlation is zero.

5. The method for stable sea surface target handover and track tracking based on navigation radar according to claim 1, characterized in that: The input of the mathematical model of full-area and track motion is the navigation radar target point track. After forward and backward correlation and extrapolation filtering calculations, the motion parameters of the target are calculated. The output of the mathematical model of full-area and track motion is the target track, a point track with a target track number, and the output track is a two-dimensional sequence with a target number.

6. A sea surface target stable handover and track tracking system based on navigation radar, characterized in that: include: Module M1: Use navigation radar to track sea surface targets, establish mathematical models of the entire area and track movement, and achieve stable tracking of multiple targets; Module M2: Analyze and select preset targets according to the characteristics of the sea surface targets of interest, or determine preset targets by integrating AIS target information, or manually specify preset targets, and extract track parameters of radar targets; Module M3: Based on the sea surface dynamic equation, input the track parameters of the radar target and solve the track parameters of the optoelectronic target; Module M4: adjust the coordinates or observation direction of the optoelectronic tracking target, continuously track the optoelectronic target, estimate the deviation between the target and the center area of ​​the image, extract the target correction parameters, and fine-tune the optoelectronic observation direction based on the target correction parameters so that the target is always located in the center of the image; Module M5: Feedback the target correction parameters to the radar target parameters, and apply multiple statistical methods to achieve automatic calibration of radar and optoelectronic system errors.

7. The sea surface target stable handover and track tracking system based on navigation radar according to claim 6 is characterized in that: According to the characteristics of radar data and echo, the video image is in the shape of a ring, with the distance sampling point sequence in azimuth angle as the echo input, and then the distance echo sequence in azimuth is added, and the scanning is carried out in a 360-degree cycle; If the radar is working in the azimuth scanning mode, the time taken for one scan is T, starting from the north clockwise, the azimuth of the scanning antenna at time t is The angular resolution of the circle is Δ β , a total of resolution units; in terms of distance, the distance resolution is Δ r , from the smallest blind spot in azimuth to the maximum range of the radar R max -R min , a total of Resolution units, take the integer, if there is a decimal, add 1; When the radar position is (x0, y0), a point (m β ,n r ), whose value is 0≤m β ≤M β ,0≤n r ≤N r According to the geometric relationship of the projection, the horizontal position (x′, y′) of the close-range target on the sea surface represented is calculated as follows: Among them, R max , R min Respectively represent the maximum and minimum distances detected by the radar; M β The number of resolution units representing the radar target azimuth; N r The number of resolution units representing the radar target distance; the measurement error follows a normal distribution with a mean of zero and variances of For a certain position (x 0t ,y 0t ), if we only care about the position of the radar relative to the target, the covariance matrix of the measurement error of the rectangular coordinates of the target is: Δx t , Δy t They represent the x and y channel measurement calculation values ​​relative to the radar position respectively; E represents the operation of taking the average; d represents the total differential operation, taking the derivative and error expansion according to the azimuth and distance; θ 0t Indicates the azimuth system error declination; Respectively represent the variance of x and y channels; σ ΔxΔy , σ ΔyΔx Respectively represent the covariance calculation of x and y channels; represents the distance measurement variance of the target; represents the target's position measurement variance; Relative to the center of the radar antenna, the three-dimensional coordinates of the target are: Among them, r t is the slant distance from the radar to the target; t is the elevation angle of the target relative to the horizontal plane of the navigation radar, which is positive when it is above and negative when it is below; β t is the angle between the target point on the radar horizontal plane and the true north direction, clockwise is positive; assume that each measurement channel has a mean of zero and a variance of Gaussian white noise; Covariance matrix of measurement errors in rectangular coordinates: σ xy , σ xz , σ yx , σ yz , σ zx , σ zy , Respectively represent the calculated variance and covariance of the three rectangular coordinates; represents the variance of the elevation angle; in: Linear deviation of angular error r t σ ε ,r t cosε t σ β , as the distance increases, the impact on the left end becomes greater and greater; the square matrix on the left end is a non-diagonal matrix, that is, there is a coupling phenomenon of errors in each component.

8. The sea surface target stable handover and track tracking system based on navigation radar according to claim 7 is characterized in that A certain position on the plane (x 0t ,y 0t ) A fixed photoelectric sensor at an altitude of h0 measures a target (x t ′,y t ′) and the relative bow azimuth and horizontal elevation angle (ε t ,β t ), the measurement error follows a normal distribution with a mean of zero and variances of Its rectangular coordinates relative to the photoelectric are: Covariance matrix of measurement errors in rectangular coordinates: σ Δx′Δy′ , σ Δy′Δx′ , represents the calculated variance and covariance of the rectangular two-coordinate of the photoelectric device; h represents the altitude at which the photoelectric device is installed; in: Relative to the center of the photoelectric antenna, the three-dimensional coordinates of the target are: Among them, r t is the slant distance from the photoelectric to the target; ε t is the elevation angle of the target relative to the horizontal plane of the navigation radar, which is positive when it is above and negative when it is below; β t The angle between the target point on the radar horizontal plane and the true north direction, clockwise is positive.

9. The sea surface target stable handover and track tracking system based on navigation radar according to claim 8 is characterized in that: Assume that the longitude and latitude of a target measured by AIS target, Beidou and GPS on the ellipsoid surface are The measurement errors follow a normal distribution with a mean of zero and variances of The covariance matrix is: The latitude and longitude cross correlation is zero.

10. The sea surface target stable handover and track tracking system based on navigation radar according to claim 6, characterized in that: The input of the mathematical model of full-area and track motion is the navigation radar target point track. After forward and backward correlation and extrapolation filtering calculations, the motion parameters of the target are calculated. The output of the mathematical model of full-area and track motion is the target track, a point track with a target track number, and the output track is a two-dimensional sequence with a target number.

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