Navigation radar based sea surface target stable handover and track keeping method and system

Abstract

The application provides a navigation radar-based sea surface target stable handover and track following method and system, which comprises: a navigation radar uses sea surface target echo for multi-target stable tracking; important targets needing to be focused on are analyzed and screened and specified; according to the positions of the radar and the photoelectric device, the photoelectric tracking target parameters are calculated by using a sea surface dynamic constraint equation or by using longitude and latitude conversion in a same station deployment; the photoelectric tracking target is guided, and the target track is dynamically fine-tuned, so that stable tracking of a stable target image is realized. Since the radar and the photoelectric device measure the coordinates of the target respectively, each data cannot be converted into three-dimensional target tracking, and the position conversion of the target cannot be realized. The application realizes that, in the case that the measurement dimensions of the sea surface target are lacking, the target can still be converted between the measurement coordinates by using the constraint equation and the longitude and latitude conversion, so that the fast guided tracking of the target is stably realized.

Description

Technical Field

[0001] This invention relates to the fields of radar and optoelectronic data processing technology, and more specifically, to a method and system for stable handover and track tracking of sea surface targets based on navigation radar. Background Technology

[0002] As a maritime frontier, the near sea is an important component of the barrier to safeguard national security. The security and stability of the near sea and coastal areas are closely related to the fundamental interests of the country, the peaceful life of the people, and even the survival and development of the nation.

[0003] Furthermore, the increasing prosperity of various marine industries depends on the navigation of numerous ships scattered across the seas. The safety of maritime routes is crucial for these ships, and the maritime shipping fleet also occupies an important position in my country's national defense reserve forces. Research related to maritime ship target surveillance includes ship identification, location, classification, and tracking. This series of tasks plays a vital role in areas such as maritime traffic management, port ship scheduling, maritime search and rescue, and maritime navigation.

[0004] Because the target detection principles of navigation radar differ significantly from those of photoelectric radar, radar is characterized by emitting electromagnetic waves, measuring the reflected waves from the target, and estimating the transmission distance and antenna azimuth when receiving the echo. Its advantages include reliable and effective target measurement at sea, largely unaffected by weather and night, but it suffers from large measurement errors. Low-cost navigation radars offer long measurement ranges but lack elevation information, only able to locate targets on the sea surface. Since the sea surface is constantly changing, it is a dynamic and wave-constrained plane, making its dynamic model very complex. When waves are small, dynamic manifold processing is used, which is extremely complex and variable. Average processing methods result in significant errors; therefore, appropriate average correction data processing methods can be employed. Photoelectric radar, on the other hand, offers high image resolution and image display capabilities. With suitable algorithms and control, continuous image tracking is possible. Its main problems are the lack of distance information, a smaller field of view, a tendency to lose targets, and jitter issues. To address the lack of distance information, a method of cross-positioning two photoelectric sensors can be used to calculate the target distance for each sensor. Radar and photoelectric radar form a relatively perfect combination, achieving fine tracking within coarse tracking, a small field of view within a large field of view, and all-weather data and image sharing. The two methods share the same coordinates but differ significantly in accuracy and granularity. Combining them organically employs a method of guiding a smaller field of view with a larger field of view.

[0005] Patent application CN117148305A discloses a target tracking method and system suitable for maritime radar. It obtains target point and trajectory information by receiving and processing echo signals in real time; then, it calculates the beam information required for tracking using the target's azimuth, uses the target distance to determine and switch the tracking beam pulse repetition frequency mode, and designs a method to delay the boundary transition zone switching. However, this patent cannot completely solve the existing technical problems, nor can it meet the needs of this invention. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the purpose of this invention is to provide a method and system for stable handover and track tracking of sea surface targets based on navigation radar.

[0007] The method for stable handover and track tracking of sea surface targets based on navigation radar provided by the present invention includes: Step S1: Use navigation radar to track sea surface targets, establish a mathematical model of the entire area and track motion, and achieve stable tracking of multiple targets; Step S2: Analyze and screen preset targets based on 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 the trajectory parameters of radar targets; Step S3: Based on the sea surface dynamic equation, input the trajectory parameters of the radar target and solve for the trajectory parameters of the electro-optical target; Step S4: Adjust the coordinates or observation direction of the photoelectric tracking target, continuously track the photoelectric target, estimate the deviation between the target and the center region of the image, extract the target correction parameters, and fine-tune the photoelectric observation direction based on the target correction parameters so that the target is always located in the center of the image; Step S5: Feed back the target correction parameters to the radar target parameters, and apply multiple statistical methods to achieve automatic calibration of radar and optoelectronic system errors.

[0008] Preferably, based on the characteristics of radar data and echo characteristics, the video image is in a circular shape, with the range sampling point sequence in the azimuth angle as the echo input, and then the range echo sequence in the azimuth angle is added, continuously scanning 360 degrees in a loop. If the radar is operating in an azimuth scanning mode, the time required to complete one scan is... Starting from due north and counting clockwise, in Continuously scan the azimuth angle of the antenna The angles of the circumference are resolved as , produced Each resolvable unit; in terms of distance, the distance resolution is... From the smallest blind spot in terms of orientation to the maximum effective range of the radar , produced Each unit of resolution is used to select an integer; if there is a decimal, add 1. When radar position Scan a point on the image area Its value is Within this range, based on the geometric relationships of the projection, it represents the horizontal position of a nearby target on the sea surface. The calculation is as follows:

[0009] or

[0010] in, , These represent the maximum and minimum detection ranges of the radar, respectively. The number of resolution units indicating the radar target's azimuth; The number of resolution units represents the radar target range; the measurement error follows a normal distribution with a mean of zero and variances of [missing information]. ; For a certain position on a plane If we only care about the radar's position relative to the target, the covariance matrix of the measurement error for the target's rectangular coordinates is:

[0011]

[0012] in:

[0013] , The x and y channels represent the measured and calculated values ​​relative to the radar position, respectively. This represents the operation of taking the average. This represents the total differential operation, differentiation by orientation and distance, and error expansion; Indicates the azimuth system error angle; , These represent the variances calculated for the x and y channels, respectively. , These represent the calculation of covariance for the x and y channels, respectively. Represents the variance of the distance measurement to the target; Indicates the variance of the target's orientation measurement; The target's three-dimensional coordinates relative to the radar antenna center are:

[0014] in, The slant range at which the radar reaches the target; The elevation angle of the target relative to the horizontal plane of the navigation radar is positive when it is above and negative when it is below. Let be the angle between the target's point on the radar horizontal plane and true north, with clockwise being positive; assume that all measurement channels follow a mean of zero and a variance of . Gaussian white noise; The covariance matrix of measurement errors in rectangular coordinates:

[0015] , , , , , , , , These represent the calculated variance and covariance of the rectangular coordinate system, respectively. The variance of the elevation angle; in: It is an orthogonal matrix; Linear deviation of angular error As the distance increases, the influence on the left end becomes greater; the left-end square matrix is ​​a non-diagonal matrix, meaning that there is a coupling phenomenon of error in each component.

[0016] Preferably, let a certain position on the plane Fixed photoelectric sensor, altitude: The location of a target was measured. Relative bow bearing and horizontal elevation angle The measurement error follows a normal distribution with a mean of zero and variances of [missing values]. Its rectangular coordinates relative to photoelectricity are:

[0017] The covariance matrix of measurement errors in rectangular coordinates:

[0018] , , , Calculate the variance and covariance of the rectangular coordinate system of photoelectric sensors; Indicates the altitude at which the optoelectronic equipment is installed; in:

[0019] The target's three-dimensional coordinates relative to the center of the photoelectric antenna are:

[0020] in, The slant distance from the photoelectric source to the target; The elevation angle of the target relative to the horizontal plane of the navigation radar is positive when it is above and negative when it is below. The angle between the point of the target on the radar horizontal plane and due north is positive, with clockwise being positive.

[0021] Preferably, the longitude and latitude of a target on the ellipsoidal surface measured by AIS, BeiDou, and GPS are denoted as . The measurement error follows a normal distribution with a mean of zero and variances of [missing values]. ; The covariance matrix is: The correlation between latitude and longitude is zero.

[0022] Preferably, the input to the mathematical model of the whole area and track motion is the target point trace of the navigation radar. After forward and backward correlation and extrapolation filtering, the motion parameters of the target are calculated. The output of the mathematical model of the whole area and track motion is the target track, the point trace with the target track number, and the output track is a two-dimensional sequence with the target number.

[0023] The navigation radar-based stable handover and track tracking system for sea surface targets provided by the present invention includes: Module M1: Uses navigation radar to track sea surface targets, establishes a mathematical model of the entire area and track motion, and achieves stable tracking of multiple targets; Module M2: Analyzes and filters preset targets based on the characteristics of the sea surface targets of interest, or determines preset targets by integrating AIS target information, or manually specifies preset targets, and extracts the trajectory parameters of radar targets; Module M3: Based on the sea surface dynamic equations, input the trajectory parameters of the radar target and solve for the trajectory parameters of the electro-optical target; Module M4: Adjusts the coordinates or observation direction of the photoelectric tracking target, continuously tracks the photoelectric target, estimates the deviation between the target and the image center region, extracts the target correction parameters, and fine-tunes the photoelectric observation direction based on the target correction parameters so that the target is always located in the image center; Module M5: Feeds back the target correction parameters to the radar target parameters and applies multiple statistical methods to achieve automatic calibration of radar and optoelectronic system errors.

[0024] Preferably, based on the characteristics of radar data and echo characteristics, the video image is in a circular shape, with the range sampling point sequence in the azimuth angle as the echo input, and then the range echo sequence in the azimuth angle is added, continuously scanning 360 degrees in a loop. If the radar is operating in an azimuth scanning mode, the time required to complete one scan is... Starting from due north and counting clockwise, in Continuously scan the azimuth angle of the antenna The angles of the circumference are resolved as , produced Each resolvable unit; in terms of distance, the distance resolution is... From the smallest blind spot in terms of orientation to the maximum effective range of the radar , produced Each resolution unit is used to select an integer; if there is a decimal, add 1. When radar position Scan a point on the image area Its value is Within this range, based on the geometric relationships of the projection, it represents the horizontal position of a nearby target on the sea surface. The calculation is as follows:

[0025] or

[0026] in, , These represent the maximum and minimum detection ranges of the radar, respectively. The number of resolution units indicating the radar target's azimuth; The number of resolution units represents the radar target range; the measurement error follows a normal distribution with a mean of zero and variances of [missing information]. ; For a certain position on a plane If we only care about the radar's position relative to the target, the covariance matrix of the measurement error for the target's rectangular coordinates is:

[0027]

[0028] in:

[0029] , The x and y channels represent the measured and calculated values ​​relative to the radar position, respectively. This represents the operation of taking the average. This represents the total differential operation, differentiation by orientation and distance, and error expansion; Indicates the azimuth system error angle; , These represent the variances calculated for the x and y channels, respectively. , These represent the calculation of covariance for the x and y channels, respectively. Represents the variance of the distance measurement to the target; Indicates the variance of the target's orientation measurement; The target's three-dimensional coordinates relative to the radar antenna center are:

[0030] in, The slant range at which the radar reaches the target; The elevation angle of the target relative to the horizontal plane of the navigation radar is positive when it is above and negative when it is below. Let be the angle between the target's point on the radar horizontal plane and true north, with clockwise being positive; assume that all measurement channels follow a mean of zero and a variance of . Gaussian white noise; The covariance matrix of measurement errors in rectangular coordinates:

[0031] , , , , , , , , These represent the calculated variance and covariance of the rectangular coordinate system, respectively. The variance of the elevation angle; in: It is an orthogonal matrix; Linear deviation of angular error As the distance increases, the influence on the left end becomes greater; the left-end square matrix is ​​a non-diagonal matrix, meaning that there is a coupling phenomenon of error in each component.

[0032] Preferably, let a certain position on the plane Fixed photoelectric sensor, altitude: The location of a target was measured. Relative bow bearing and horizontal elevation angle The measurement error follows a normal distribution with a mean of zero and variances of [missing values]. Its rectangular coordinates relative to photoelectricity are:

[0033] The covariance matrix of measurement errors in rectangular coordinates:

[0034] , , , Calculate the variance and covariance of the rectangular coordinate system of photoelectric sensors; Indicates the altitude at which the optoelectronic equipment is installed; in:

[0035] The target's three-dimensional coordinates relative to the center of the photoelectric antenna are:

[0036] in, The slant distance from the photoelectric source to the target; The elevation angle of the target relative to the horizontal plane of the navigation radar is positive when it is above and negative when it is below. The angle between the point of the target on the radar horizontal plane and due north is positive, with clockwise being positive.

[0037] Preferably, the longitude and latitude of a target on the ellipsoidal surface measured by AIS, BeiDou, and GPS are denoted as . The measurement error follows a normal distribution with a mean of zero and variances of [missing values]. ; The covariance matrix is: The correlation between latitude and longitude is zero.

[0038] Preferably, the input to the mathematical model of the whole area and track motion is the target point trace of the navigation radar. After forward and backward correlation and extrapolation filtering, the motion parameters of the target are calculated. The output of the mathematical model of the whole area and track motion is the target track, the point trace with the target track number, and the output track is a two-dimensional sequence with the target number.

[0039] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention combines the spherical target characteristics of navigation radar with spherical constraint equations to realize the transformation from two-dimensional coordinates to three-dimensional coordinates, and then transforms it into the pointing coordinates of the photoelectric image center through the spherical center rectangular coordinates. It can also solve the photoelectric target distance. Its transformation error is an order of magnitude smaller than other methods, and it is highly efficient. The system is economical and practical. 2. Based on the target performance of navigation radar and the target characteristics of photoelectric targets, this invention realizes measurement coordinate transformation based on ellipsoidal constraints, solving the problem of coordinate transformation and allowing for many extensions. For example, the center of the photoelectric target can be used to track low-altitude UAVs and tall ships; multiple stations can be guided to simultaneously track photoelectric targets; multi-station photoelectric targets can achieve image fusion; and photoelectric targets can guide radar targets, etc. 3. After initial verification, the method of this invention was improved several times. The module implemented was applied in a multi-element joint sensing system and achieved good results in radar-guided moving target detection and stationary target detection. Attached Figure Description

[0040] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a system flowchart of the present invention; Figure 2 A map of a fishing ground used to guide photoelectric tracking operations in areas with strong radar clutter. Figure 3Image of a radar-guided photoelectric tracking boat; Figure 4 Diagram showing radar-guided photoelectric tracking of a small cargo ship; Figure 5 Diagram of radar-guided photoelectric tracking beacon; Figure 6 Image showing radar-guided electro-optical tracking of a fishing vessel. Detailed Implementation

[0041] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0042] Example 1 This invention discloses a method and system implementation for moving target detection in a strong cluttered sea environment, such as... Figure 1 As shown, it includes: By utilizing navigation radar and photoelectric joint detection and tracking of sea surface targets, and enabling mutual guidance and fusion of targets in the event of incomplete information, it is possible to quickly obtain evidence and authenticate illegal targets at sea, organize effective countermeasures, and play a very important role and significance in border defense and anti-smuggling.

[0043] The main steps are as follows: 1) The target is at geographic coordinates Transformation to geocentric rectangular coordinates

[0044] The above formula can be expressed as:

[0045] in, These represent the major and minor axes of the Earth's ellipsoid, and the altitude, respectively. This method can be used to calculate the altitude of any target at any station or any point on the ellipsoid or in space.

[0046] Radius of curvature of the zonal circle: According to the 2000 China Geodetic Coordinate System (CGCS2000). For the Earth's semi-major axis, eccentricity , 6378137m, 6356752.314m, 0.0818191913087; Elliptic flattening .

[0047] 2) From geocentric rectangular coordinates to geographic coordinates Conversion

[0048] As can be seen from the above formula, iterative steps are required to convert the target location with altitude into latitude information.

[0049] When the altitude is zero, the target is on the ellipsoid.

[0050] 3) Constraint equations for the ellipsoidal surface The latitude, longitude, and altitude of the radar site The target measurement coordinates of the sensor Substituting into the above formula, the surface of the ellipsoid can be calculated. Location:

[0051] If the target being measured has an altitude on the surface of an ellipsoid, the following relationship holds: like Then we have the ellipsoidal constraint equation:

[0052] like Then we have the ellipsoidal constraint equation:

[0053] For radar, the azimuth and range of a target can be measured. Using the constraint relationship on an ellipsoid, after complex simplification, and considering the case where the range is less than 100km, the ellipsoid is simplified to an equivalent sphere, yielding a quadratic equation for the range. The constraint equation for the spherical target is as follows:

[0054] The above formula also imposes constraints on photoelectric sensors. That is, given the elevation angle of the target, the distance from the photoelectric sensor to the spherical target can be estimated. However, when calculating the parameters in the equation, it is necessary to calculate them according to the latitude, longitude, and altitude of the photoelectric sensor.

[0055] Given the target distance, the elevation angle can be determined:

[0056]

[0057] For radar station 1, the target's elevation angle can be calculated, and substituting it into the following formula yields:

[0058] The subscript 1 indicates a measurement or calculated value from radar station 1. The parameters can be substituted into the three-dimensional error covariance matrix to approximately calculate the variance of the rectangular coordinates.

[0059] 4) Transform from the geocentric rectangular coordinate system to the rectangular coordinate system of the photovoltaic power station 2. For convenience, the radar station is designated 01, and the optoelectronic station is designated 02. The latitude, longitude, and altitude of each station (which can be determined using BeiDou or GPS) are known. The target measurement coordinates of the sensors at both stations are converted to an ellipsoidal rectangular coordinate system. The radar measures the same batch of targets, and the rectangular coordinates of the target centers are consistent.

[0060] The target rectangular coordinates of photovoltaic power station 02 can be obtained:

[0061] Because of the 3 in the above formula 3. The matrix is ​​an orthogonal matrix, and its inverse is the matrix transpose. The above equation can be further simplified.

[0062] If the radar and photoelectric sensors are on the same tower and at similar altitudes, the first term in the curly braces of the above formula is zero.

[0063] The rectangular coordinates of the photovoltaic power station target have been determined. Next, determine the elevation angle and azimuth of the photoelectric observation target:

[0064] Calculate the target's distance, azimuth, and elevation relative to the infrared tracking system based on the extrapolated values;

[0065] Among them, elevation angle For negative values, In approach We need to determine the location based on the maximum distance.

[0066] The photoelectric system tracks the target using the calculated azimuth and elevation angles of the target as the target center.

[0067] A comprehensive assessment of targets is crucial: when a radar target is designated as a key target of interest by higher authorities; when a radar target's track originates from a special sea area or sensitive region, it requires monitoring, and electro-optical tracking and assessment should be initiated; when a target's AIS information exhibits anomalies (change of number, alteration, intermittent activity, etc.), electro-optical tracking and image evidence collection should be activated; when a target's track exhibits special characteristics, such as hovering, circling, or prolonged stays, electro-optical tracking and image evidence collection are also necessary. Depending on the needs of different industries, various experiences and specific processes exist for assessment to determine key targets of interest.

[0068] When a target is identified and targeted for photoelectric image tracking, a request is sent to the display and control system to estimate the target's center coordinates (elevation and azimuth) within the photoelectric system. The photoelectric system is then rapidly moved to the target's location, and the search and fine-tuning process ensures the target remains within a certain frame near the center, thus achieving photoelectric tracking of the moving target.

[0069] This paper describes the basic principles of coordinate extension and target transformation between two sensor stations under spherical constraints. Based on ellipsoidal coordinates, the spherical constraint equations are derived, and the calculation and transformation process for estimating the new coordinates is presented. The paper achieves mutual transformation between the coordinates of a (partially measured) target at two stations under ellipsoidal constraints, thus mitigating the problems caused by incomplete measurements.

[0070] During photoelectric target tracking, the photoelectric center should always be aligned with the moving target (near the center). This can be achieved by manually adjusting the photoelectric interface. However, during the conversion process, factors such as calculation errors, (constraint equation) model errors, conversion errors, sea level tides, system deviations between the two sensors, target measurement errors, and station location errors require system analysis. Statistical analysis of the deviation between the target image center and the photoelectric center, along with the magnitude of the deviation sequence, can determine which factors are dominant and allow for further adjustments to the system error. Alternatively, the photoelectric image center can be directly fine-tuned to always keep the target center aligned with the image center. This is because different systems have different dominant factors, requiring system analysis and necessary compensation.

[0071] like Figure 1 The diagram shows the components of the navigation radar-guided optoelectronic system, the relationships between the modules, and the information transmission process.

[0072] like Figure 2 As shown, the detection of small wooden boats in the aquaculture area under strong clutter and non-coherent moving targets (left image is radar image, upper right image is photoelectric image, lower right image is infrared image) shows photoelectric tracking of multiple small boat tracks within and around the aquaculture area.

[0073] like Figure 3 As shown, the radar target tag can be seen in the display and control system, which includes various flight paths. Clicking on the target will directly guide the photoelectric process. The photoelectric system can stably track small boats, and its tracking is very effective.

[0074] like Figure 4 As shown, the radar target tag can be seen in the display and control system, which includes various flight paths. Clicking on the target will directly guide the photoelectric process. The photoelectric system can stably track small cargo ships, and its tracking is very stable.

[0075] like Figure 5 As shown, the radar target tag can be seen in the display and control system, which includes various flight paths. Clicking on the target tag will directly guide the photoelectric process. The photoelectric system can stably track the beacon, and its tracking is very stable.

[0076] like Figure 6 As shown, the radar target tag can be seen in the display and control system, which includes various flight paths. Clicking on the target will directly guide the photoelectric process. The photoelectric system can stably track larger fishing boats, and its tracking is very stable and effective.

[0077] Implementation process and improvement methods: This invention, based on the incomplete measurement characteristics of navigation radar and optoelectronic systems, and considering the characteristics of maritime targets, combines ellipsoidal constraint equations to achieve three-dimensional tracking of sea-level targets, achieving good results. During the development process, the following improvements were made: 1) The calculation method of the constraint equation parameters was significantly improved, employing high-precision calculation of ellipsoidal parameters; 2) Data on sea level rise or fall was used to correct the ellipsoidal parameters; 3) The calculation process was analyzed, key steps were optimized, and the algorithm module was improved; 4) The statistical and correction processes were continuously improved to achieve smooth and accurate guidance and fast and stable tracking; 5) New applications are still under development, including debugging new systems (guiding multiple optoelectronic devices, large-scale networking, etc.). Several minor issues were also discovered during actual testing, and the software modules were modified and improved accordingly. Based on the actual test results, this method is effective.

[0078] Example 2 This invention relates to a navigation radar-guided photoelectric system for effective tracking of targets on the sea surface. This plays a crucial role in the rapid detection, image evidence collection, and identification of illegal targets at sea. The implementation principle and improvement methods are presented, with a detailed explanation of the system implementation process and discussion of problems. After initial verification, the method was further improved multiple times. The implemented module, applied in a multi-element joint sensing system, achieved rapid, stable, and reliable tracking, significantly enhancing the detection, tracking, and evidence collection capabilities for various illegal targets. Specifically, it includes the following modules: Module M1: Navigation Radar Sea Surface Target Detection and Tracking Module: This module employs a sea surface target detection and tracking software module. Since navigation radar is a two-dimensional radar, it offers high efficiency and reliability in scanning sea surface targets, while being economical, resulting in the best performance-price ratio. Achieving radar target detection and tracking on the sea surface has significant engineering application value. The detection and tracking module utilizes ES3.0 (see our company's invention patent), achieving advanced capabilities in suppressing strong sea surface clutter and detecting and tracking small targets. The application module demonstrates strong track persistence for sea surface targets, suppresses interference from various sea clutter sources, and enhances small target detection capabilities. By using navigation radar to track sea surface targets, a mathematical model of the entire area and track motion is established to achieve stable multi-target tracking. Module M2: Important Target Screening Module: Analyzes and screens important targets based on their characteristics, considering factors such as the target's location, origin and destination, time and location, sea conditions and weather, historical information, draft, and trajectory characteristics (detour, curve, speed, stop, movement, etc.). Depending on specific user requirements, it may also include multi-sensor target fusion trajectory information, AIS target (illegal / non-compliant targets) information determination, or (commander's) manually designated important targets. It separates the trajectory of targets requiring focused attention and further identification and authentication, extracting important sea surface targets and their trajectory parameters; these are then sent to the coordinate calculation module via the display and control system. Module M3: Coordinate Calculation and Electro-optical Center Pointing Parameter Calculation Module: Based on the latitude, longitude, and altitude of the radar site, and according to the constraint equations of the ellipsoidal target, the elevation angle information of the radar target is calculated to obtain the target's three-dimensional coordinates. After rotation and translation transformation of the ellipsoidal coordinates (different locations and the same location), the pointing center of the electro-optical system is obtained. The pointing information guides the electro-optical tracking of the target.

[0079] Module M4: Fine-tuning and calibration module: This module statistically analyzes the error sequence between the weighted center of the target image and the actual image center. It automatically adjusts the weighted center to gradually align with the actual image center, or allows manual adjustment of the image center by using the up, down, left, and right arrow keys to ensure the two centers are essentially aligned. Since different systems have different error models, the module analyzes the main factors contributing to the error sequence and performs necessary system error compensation.

[0080] Those skilled in the art will understand that, in addition to implementing the system, apparatus, and their modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and their modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.

[0081] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, 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. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for stable handover and track tracking of sea surface targets based on navigation radar, characterized in that, include: Step S1: Use navigation radar to track sea surface targets, establish a mathematical model of the entire area and track motion, and achieve stable tracking of multiple targets; Step S2: Analyze and screen preset targets based on 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 the trajectory parameters of radar targets; Step S3: Based on the sea surface dynamic equation, input the trajectory parameters of the radar target and solve for the trajectory parameters of the electro-optical target; Step S4: Adjust the coordinates or observation direction of the photoelectric tracking target, continuously track the photoelectric target, estimate the deviation between the target and the center region of the image, extract the target correction parameters, and fine-tune the photoelectric observation direction based on the target correction parameters so that the target is always located in the center of the image; Step S5: Feed back the target correction parameters to the radar target parameters, and apply multiple statistical methods to achieve automatic calibration of radar and optoelectronic system errors; Based on the characteristics of radar data and echoes, the video image is circular in shape. The range sampling point sequence in the azimuth angle is used as the echo input, and then the range echo sequence in the azimuth angle is added, and the 360-degree loop scan is continuously performed. If the radar is operating in an azimuth scanning mode, the time required to complete one scan is... Starting from due north and counting clockwise, in Continuously scan the azimuth angle of the antenna The angles of the circumference are resolved as , produced Each resolvable unit; in terms of distance, the distance resolution is... From the smallest blind spot in terms of orientation to the maximum effective range of the radar , produced Each resolution unit is used to select an integer; if there is a decimal, add 1. When radar position Scan a point on the image area Its value is Within this range, based on the geometric relationships of the projection, it represents the horizontal position of a nearby target on the sea surface. The calculation is as follows: or in, , These represent the maximum and minimum detection ranges of the radar, respectively. The number of resolution units indicating the radar target's azimuth; The number of resolution units represents the radar target range; the measurement error follows a normal distribution with a mean of zero and variances of [missing information]. ; For a certain position on a plane If we only care about the radar's position relative to the target, the covariance matrix of the measurement error for the target's rectangular coordinates is: in: , The x and y channels represent the measured and calculated values ​​relative to the radar position, respectively. This represents the operation of taking the average. This represents the total differential operation, differentiation by orientation and distance, and error expansion; Indicates the azimuth system error angle; , These represent the variances calculated for the x and y channels, respectively. , These represent the calculation of covariance for the x and y channels, respectively. Represents the variance of the distance measurement to the target; Indicates the variance of the target's orientation measurement; The target's three-dimensional coordinates relative to the radar antenna center are: in, The slant range at which the radar reaches the target; The elevation angle of the target relative to the horizontal plane of the navigation radar is positive when it is above and negative when it is below. Let be the angle between the target's point on the radar horizontal plane and true north, with clockwise being positive; assume that all measurement channels follow a mean of zero and a variance of . Gaussian white noise; The covariance matrix of measurement errors in rectangular coordinates: , , , , , , , , These represent the calculated variance and covariance of the rectangular coordinate system, respectively. The variance of the elevation angle; in: It is an orthogonal matrix; Linear deviation of angular error As the distance increases, the influence on the left end becomes greater; the left-end square matrix is ​​a non-diagonal matrix, meaning that there is a coupling phenomenon of error in each component; Suppose a certain position in a plane Fixed photoelectric sensor, altitude: The location of a target was measured. Relative bow bearing and horizontal elevation angle The measurement error follows a normal distribution with a mean of zero and variances of [missing values]. Its rectangular coordinates relative to photoelectricity are: The covariance matrix of measurement errors in rectangular coordinates: , , , Calculate the variance and covariance of the rectangular coordinate system of photoelectric sensors; Indicates the altitude at which the optoelectronic equipment is installed; in: The target's three-dimensional coordinates relative to the center of the photoelectric antenna are: in, The slant distance from the photoelectric source to the target; The elevation angle of the target relative to the horizontal plane of the navigation radar is positive when it is above and negative when it is below. The angle between the point of the target on the radar horizontal plane and due north is positive, with clockwise being positive.

2. The method for stable handover and track tracking of sea surface targets based on navigation radar according to claim 1, characterized in that, Suppose that the longitude and latitude of a certain target on the surface of an ellipsoid are measured by AIS, BeiDou, and GPS. The measurement error follows a normal distribution with a mean of zero and variances of [missing values]. ; The covariance matrix is: The correlation between latitude and longitude is zero.

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

4. A stable handover and track tracking system for sea surface targets based on navigation radar, characterized in that, include: Module M1: Uses navigation radar to track sea surface targets, establishes a mathematical model of the entire area and track motion, and achieves stable tracking of multiple targets; Module M2: Analyzes and filters preset targets based on the characteristics of the sea surface targets of interest, or determines preset targets by integrating AIS target information, or manually specifies preset targets, and extracts the trajectory parameters of radar targets; Module M3: Based on the sea surface dynamic equations, input the trajectory parameters of the radar target and solve for the trajectory parameters of the electro-optical target; Module M4: Adjusts the coordinates or observation direction of the photoelectric tracking target, continuously tracks the photoelectric target, estimates the deviation between the target and the image center region, extracts the target correction parameters, and fine-tunes the photoelectric observation direction based on the target correction parameters so that the target is always located in the image center; Module M5: Feeds back the target correction parameters to the radar target parameters and applies multiple statistical methods to achieve automatic calibration of radar and optoelectronic system errors; Based on the characteristics of radar data and echoes, the video image is circular in shape. The range sampling point sequence in the azimuth angle is used as the echo input, and then the range echo sequence in the azimuth angle is added, and the 360-degree loop scan is continuously performed. If the radar is operating in an azimuth scanning mode, the time required to complete one scan is... Starting from due north and counting clockwise, in Continuously scan the azimuth angle of the antenna The angles of the circumference are resolved as , produced Each resolvable unit; in terms of distance, the distance resolution is... From the smallest blind spot in terms of orientation to the maximum effective range of the radar , produced Each resolution unit is used to select an integer; if there is a decimal, add 1. When radar position Scan a point on the image area Its value is Within this range, based on the geometric relationships of the projection, it represents the horizontal position of a nearby target on the sea surface. The calculation is as follows: or in, , These represent the maximum and minimum detection ranges of the radar, respectively. The number of resolution units indicating the radar target's azimuth; The number of resolution units represents the radar target range; the measurement error follows a normal distribution with a mean of zero and variances of [missing information]. ; For a certain position on a plane If we only care about the radar's position relative to the target, the covariance matrix of the measurement error for the target's rectangular coordinates is: in: , The x and y channels represent the measured and calculated values ​​relative to the radar position, respectively. This represents the operation of taking the average. This represents the total differential operation, differentiation by orientation and distance, and error expansion; Indicates the azimuth system error angle; , These represent the variances calculated for the x and y channels, respectively. , These represent the calculation of covariance for the x and y channels, respectively. Represents the variance of the distance measurement to the target; Indicates the variance of the target's orientation measurement; The target's three-dimensional coordinates relative to the radar antenna center are: in, The slant range at which the radar reaches the target; The elevation angle of the target relative to the horizontal plane of the navigation radar is positive when it is above and negative when it is below. Let be the angle between the target's point on the radar horizontal plane and true north, with clockwise being positive; assume that all measurement channels follow a mean of zero and a variance of . Gaussian white noise; The covariance matrix of measurement errors in rectangular coordinates: , , , , , , , , These represent the calculated variance and covariance of the rectangular coordinate system, respectively. The variance of the elevation angle; in: It is an orthogonal matrix; Linear deviation of angular error As the distance increases, the influence on the left end becomes greater; the left-end square matrix is ​​a non-diagonal matrix, meaning that there is a coupling phenomenon of error in each component; Suppose a certain position in a plane Fixed photoelectric sensor, altitude: The location of a target was measured. Relative bow bearing and horizontal elevation angle The measurement error follows a normal distribution with a mean of zero and variances of [missing values]. Its rectangular coordinates relative to photoelectricity are: The covariance matrix of measurement errors in rectangular coordinates: , , , Calculate the variance and covariance of the rectangular coordinate system of photoelectric sensors; Indicates the altitude at which the optoelectronic equipment is installed; in: The target's three-dimensional coordinates relative to the center of the photoelectric antenna are: in, The slant distance from the photoelectric source to the target; The elevation angle of the target relative to the horizontal plane of the navigation radar is positive when it is above and negative when it is below. The angle between the point of the target on the radar horizontal plane and due north is positive, with clockwise being positive.

5. The sea surface target stable handover and track tracking system based on navigation radar according to claim 4, characterized in that, Suppose that the longitude and latitude of a certain target on the surface of an ellipsoid are measured by AIS, BeiDou, and GPS. The measurement error follows a normal distribution with a mean of zero and variances of [missing values]. ; The covariance matrix is: The correlation between latitude and longitude is zero.

6. The sea surface target stable handover and track tracking system based on navigation radar according to claim 4, characterized in that, The mathematical model for full-area and track motion takes the target point as input from the navigation radar. After forward and backward correlation and extrapolation filtering, the motion parameters of the target are calculated. The output of the mathematical model for full-area and track motion is the target track, which is a point with the target track number. The output track is a two-dimensional sequence with the target number.

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