A method for displaying echoes of a navigation radar based on double buffering

Abstract

The application discloses a display method of echo trail of a navigation radar based on double caches, which comprises the following steps: 1, adding a memory cache area: a memory cache area is added on the basis of an existing picture cache area; 2, receiving echo; 3, radial echo data A fusion cache; 4, picture cache: when a user performs any operation of eccentricity change and range change, the picture cache area is emptied; then, data in the memory cache area after fusion in step 3 is read and updated to the picture cache area; otherwise, radial echo data A received in step 2 is directly updated to the picture cache area; 5, drawing the trail. The application can realize continuous and real display of the trail in the case of eccentricity change or mode switching (display mode switching or motion mode switching), can diversify the display and diversify the operation, and thus can adapt to more complex and changeable marine environments.

Description

Technical Field

[0001] This invention relates to the field of radar display and control, and in particular to a method for displaying the wake trail of a navigation radar based on dual buffers. Background Technology

[0002] As the eyes of maritime navigation, navigation radar is typically only run in the background during radar display and control operations. By default, AIS is displayed silently. Only when manual intervention is required will the corresponding target be recorded and detailed AIS information be viewed. This is because displaying too many symbols and text information on the screen can appear particularly cluttered in complex sea conditions and may even obscure key echoes, leading to accidents.

[0003] During the periods when AIS is in silent mode, users typically turn on the wake display to intuitively determine the heading and approximate speed of the target vessel ahead by observing the direction and length of the wake.

[0004] However, current wake display methods are all based on image caching, which can only handle stable maritime environments and are difficult to solve in complex maritime environments. In complex maritime environments, complex maneuvers are usually required to better observe the surrounding environment and achieve the purpose of risk avoidance.

[0005] The aforementioned complex maritime environment includes situations such as entering and leaving ports, the presence of numerous fishing boats and nets in nearshore waters, and proximity to reefs.

[0006] The aforementioned complex operations include eccentricity, range changes, and operating mode changes.

[0007] The aforementioned eccentricity refers to the user's ability to better observe the surrounding environment by dragging or rotating the displayed layer.

[0008] The aforementioned range change refers to the user scaling the display layer to better observe the surrounding environment.

[0009] Changes in operating modes include changes in display mode and motion mode.

[0010] Existing technologies, while offering the advantage of speed through image caching, also have significant drawbacks: the image cache size is fixed based on the current display area and cannot be updated; therefore, when users perform operations such as dragging and range changes, the original image cache must be cleared and refilled with new data, resulting in the loss of the original trailing image. Furthermore, dragging and range changes consume considerable memory, and the system cannot afford to spend excessive memory on the image buffer. Moreover, image movement and positioning are prone to errors when redrawing the image cache.

[0011] Display modes include north-facing display mode and non-north-facing display mode; when the coordinate system changes, such as when the coordinate system changes to a non-north-facing display mode, users usually need to perform operations such as rotating the display layer to facilitate the judgment of various information such as the heading and approximate speed of the target ship ahead.

[0012] In existing technologies, when the display layer rotates at an angle, it does so with the display center as the reference point. When the target ship makes frequent, large-angle turns, since the rotation reference point is the display center, the angle needs to be calculated. The angle change will inevitably lead to changes in the x and y directions, causing the radar position to shift angularly around the display center point. Specifically... Figure 2 As shown, this makes it impossible for the echo and wake to be displayed stably.

[0013] Motion patterns include relative motion patterns and absolute motion patterns.

[0014] The relative motion mode described above displays a relative wake, which is the trajectory relative to the ship itself. Only the absolute motion mode displays an absolute wake, also known as a ground-based wake. However, in practical applications, the reference value of a relative wake is far less than that of an absolute wake. This is because only an absolute wake can more realistically and objectively show whether the object representing the current echo is moving or stationary, and whether its speed is fast or slow. The size of the ship can be judged based on the length and width of the echo. Since the wake displays an absolute ground-based wake, the ship's heading and approximate speed can be intuitively determined based on the direction and length of the wake. Therefore, an absolute wake can more accurately and intuitively reflect the motion state of a target ship. For example, a reef that emerges from the water has no wake because it is stable relative to the ground; it can be easily avoided. However, a relative wake shows the ship moving at the same speed but in the opposite direction, making it difficult to judge.

[0015] Therefore, when a ship is in a relative motion mode, its wake will be difficult to determine. Summary of the Invention

[0016] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a method for displaying wakes based on dual-buffered navigation radar echoes. This method has the advantages of fast image buffering and wake display, and can restore the original wake level within one cycle in the event of eccentricity or mode switching, without increasing the computer load.

[0017] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0018] A method for displaying the wake of navigation radar echoes based on dual buffers includes the following steps.

[0019] Step 1: Add a memory buffer area: The radar display control has an echo display buffer area and a wake display buffer area; the wake display buffer area adds a memory buffer area on the basis of the existing image buffer area; the memory buffer area and the image buffer area have the same timer to achieve a synchronous reduction display effect.

[0020] Step 2, Receiving Echoes: The radar display and control system receives a new radial echo data A. Let the azimuth angle of the radial echo data A be α, and the echo intensity of the radial echo data A be H1.

[0021] Step 3: Radial echo data A fusion cache: Read the echo intensity H0 of the radial echo data at azimuth angle α in the memory cache area, and compare H0 with H1; when H1 > H0, the radial echo data A is superimposed on the azimuth angle α and cached; otherwise, the radial echo data A will not be cached.

[0022] Step 4, Image caching: Determine whether the user has performed any eccentricity or range change operations at the current moment.

[0023] A. When the user performs either the eccentricity or range change operation, the image cache is cleared; then, radial echo data is read from the memory cache fused in step 3, and the read radial echo data is updated to the image cache.

[0024] B. If the user does not perform any operation of eccentricity or range change, the radial echo data A received in step 2 will be directly updated to the image cache area.

[0025] Step 5: Draw the wake: Based on the radial echo data in the image buffer area in Step 4, draw the radar echo wake image on the layer below the radar echo image.

[0026] It also includes step 6, displaying the trail in different display modes, which specifically includes the following steps:

[0027] Step 6-1: Determine the display mode: Determine the current display mode of the interface; the display mode includes north-facing display mode and non-north-facing display mode.

[0028] Step 6-2, Rotation: Rotate the radar echo wake image from Step 5 according to the display mode to facilitate the identification of target ships ahead; the specific rotation method is as follows:

[0029] A. When the display mode is north-facing, the radar echo wake image in step 5 remains unchanged.

[0030] B. When the display mode is not due north upward display mode, first use the radar center as the base point to synchronously rotate the radar echo image, radar echo wake image and non-radar image in the current display interface in step 5.

[0031] Step 6-3, Offset: Let the coordinates of the display center before rotation be point O. After rotating with the radar center as the base point, the original display center rotates to point O1. Based on the distance from the original display center point O to the radar center and the rotation angle in step 6-2, calculate the latitude and longitude of point O1 to facilitate the offset of the latitude and longitude coordinate system.

[0032] It also includes step 7, displaying the wake under different motion modes, which specifically includes the following steps:

[0033] Step 7-1: Determine the motion pattern: Based on the set motion pattern of the target, the motion pattern includes relative motion pattern and absolute motion pattern; where, relative motion pattern refers to the motion pattern of the target relative to the ship; absolute motion pattern refers to the motion pattern of the target relative to the ground.

[0034] Step 7-2, Displaying Absolute Trail: When the motion mode is absolute motion mode, the trail displayed in step 5 or step 6 is an absolute trail; when the motion mode is relative motion mode, the trail displayed in step 5 or step 6 is a relative trail; in this case, the display effect of an absolute trail in relative motion mode needs to be achieved by reversing the movement of the trail.

[0035] In step 7-2, the method of reverse wake movement is as follows: First, calculate the direction and distance C of the target's movement relative to the ship; then, move the image cache of the relative wake in the opposite direction of the ship's heading by the same distance C to achieve the display effect of the absolute wake in the state of relative motion.

[0036] It also includes step 8, which repeats steps 2 to 7 to display the wake of the next new radial echo data.

[0037] In step 1, both the image cache and the memory cache are created based on the maximum length of the radial data and the maximum number of radial data.

[0038] In step 1, the time interval dTimer needs to be calculated based on the trail display time t selected by the user. The specific calculation formula is as follows:

[0039] dTimer = t * 60 * 1000 / 255

[0040] In the formula, dTimer is in milliseconds and t is in minutes.

[0041] The present invention has the following beneficial effects:

[0042] 1. This invention has the advantages of fast image buffering and display of wakes, and can restore the original wake level within one cycle even in the event of eccentricity or mode switching, without increasing the computer load. In other words, it can stably display wakes according to the usage habits and actual display requirements of the ship's crew.

[0043] 2. This invention adds a memory cache area on the basis of the existing image cache area, and the data reduction is consistent with the image reduction. Therefore, when dragging and switching ranges, the data can be directly used to fill the trail cache to achieve continuous trail display.

[0044] 3. This invention can achieve continuous and realistic display of the wake depending on the display mode and motion mode, which not only diversifies the display but also diversifies the operation, thus adapting to more complex and changeable marine environments. Attached Figure Description

[0045] Figure 1 This is a flowchart of a method for displaying the echo wake of a navigation radar based on dual buffers, according to the present invention.

[0046] Figure 2 This diagram illustrates the angular rotation performed with the display center as the reference point in the prior art.

[0047] Figure 3 The diagram shows the present invention rotating at an angle with the radar center as the reference point.

[0048] Figure 4 This diagram illustrates the wake at a non-eccentric distance of 16 nautical miles in this embodiment.

[0049] Figure 5 This diagram illustrates the wake at 16 nautical miles of eccentricity in this embodiment. Detailed Implementation

[0050] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

[0051] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.

[0052] like Figure 1As shown, a method for displaying the echo wake of a navigation radar based on dual buffers includes the following steps.

[0053] Step 1: Add a memory cache area

[0054] The radar display and control system has an echo display buffer area and a wake display buffer area; the wake display buffer area adds a memory buffer area on the basis of the existing image buffer area.

[0055] In this embodiment, both the image cache area and the memory cache area are created based on the maximum length of the radial data and the maximum number of radial data.

[0056] The memory cache and image cache share the same timer to achieve synchronized display reduction. The timer interval dTimer is calculated based on the user-selected trail display time t, using the following formula:

[0057] dTimer = t * 60 * 1000 / 255

[0058] In the formula, dTimer is in milliseconds and t is in minutes.

[0059] Step 2, Receiving Echoes: The radar display and control system receives a new radial echo data A. Let the azimuth angle of the radial echo data A be α, and the echo intensity of the radial echo data A be H1.

[0060] Step 3: Radial echo data A fusion cache: Read the echo intensity H0 of the radial echo data at azimuth angle α in the memory cache area, and compare H0 with H1; when H1 > H0, the radial echo data A is superimposed on the azimuth angle α and cached; otherwise, the radial echo data A will not be cached.

[0061] Step 4, Image caching: Determine whether the user has performed any eccentricity or range change operations at the current moment.

[0062] A. When the user performs any of the following operations: eccentricity (such as dragging) or range change (such as scaling), the image cache is cleared. Then, radial echo data is read from the memory cache after fusion in step 3, and the read radial echo data is updated to the image cache.

[0063] B. If the user does not perform any operation of eccentricity or range change, the radial echo data A received in step 2 will be directly updated to the image cache area.

[0064] In this embodiment, a schematic diagram showing the wake at a non-eccentric distance of 16 nautical miles is provided, as follows: Figure 4 As shown; a schematic diagram illustrating the wake at 16 nautical miles with eccentricity, as follows. Figure 5 As shown.

[0065] Step 5: Draw the wake: Based on the radial echo data in the image buffer area in Step 4, draw the radar echo wake image on the layer below the radar echo image.

[0066] Step 6, displaying the trail in different display modes, specifically includes the following steps:

[0067] Step 6-1: Determine the display mode: Determine the current display mode of the interface; the display mode includes north-facing display mode and non-north-facing display mode.

[0068] Step 6-2, Rotation: Rotate the radar echo wake image from Step 5 according to the display mode to facilitate the identification of target ships ahead; the specific rotation method is as follows:

[0069] A. When the display mode is north-facing, the radar echo wake image in step 5 remains unchanged.

[0070] North-up is a stable mode, and the echo will not rotate due to the ship's rotation. Therefore, radar echoes are transmitted in a north-up mode.

[0071] B. When the display mode is not a north-facing display mode, such as Figure 3 As shown, the radar echo image, radar echo wake image, and non-radar image in the current display interface are rotated synchronously with the radar center as the base point.

[0072] Non-north-facing display modes include bow-up display mode and heading-up display mode.

[0073] When the display mode is bow-up display mode, let β be the angle between the bow of the ship and due north. Then, with the radar center as the base point, the radar echo image, radar echo wake image and non-radar image in the current display interface are all rotated synchronously by angle β.

[0074] When the display mode is heading upwards, let λ be the angle between the ship's heading and due north. Then, with the radar center as the base point, the radar echo image, radar echo wake image, and non-radar image in the current display interface are all rotated synchronously by the angle λ.

[0075] Step 6-3, Offset: Let the coordinates of the display center before rotation be point O. After rotating with the radar center as the base point, the original display center rotates to point O1. Based on the distance from the original display center point O to the radar center and the rotation angle in step 6-2, calculate the latitude and longitude of point O1 to facilitate the offset of the latitude and longitude coordinate system, thereby facilitating the stable display of AIS and nautical charts.

[0076] In this embodiment, since the rotation is based on the radar center, the position of the radar center will not change no matter how it rotates. Therefore, the latitude and longitude of the display center point can be calculated by back-calculating the radar position, the distance to the display center, and the rotation angle, so that the echo and wake can be displayed stably.

[0077] Step 7: Displaying the wake under different motion modes, specifically including the following steps.

[0078] Step 7-1: Determine the motion pattern: Based on the set motion pattern of the target, the motion pattern includes relative motion pattern and absolute motion pattern.

[0079] Relative motion mode refers to the motion mode of the target relative to the ship itself; in this mode, the displayed image is relative to the ship itself, the ship is stationary, and the target, such as the target ship or land, moves in the opposite direction to the ship's course.

[0080] Absolute motion mode refers to the motion mode of the target relative to the ground. In this mode, the land is stationary, and all other objects are moving relative to the land.

[0081] Step 7-2, Displaying Absolute Trail: When the motion mode is absolute motion mode, the trail displayed in step 5 or step 6 is an absolute trail; when the motion mode is relative motion mode, the trail displayed in step 5 or step 6 is a relative trail; in this case, the display effect of an absolute trail in relative motion mode needs to be achieved by reversing the movement of the trail.

[0082] The preferred method for reverse wake movement described above is as follows: first, calculate the direction and distance C of the target's movement relative to the ship; then, move the image cache of the relative wake in the opposite direction of the ship's heading by the same distance C to achieve the display effect of the absolute wake in the relative motion state.

[0083] Step 8: Repeat steps 2 to 7 to display the wake of the next new radial echo data.

[0084] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A method for displaying echo wakes from dual-buffered navigation radar, characterized in that: Includes the following steps: Step 1: Add a memory buffer: The radar display has an echo display buffer and a wake display buffer; the wake display buffer adds a memory buffer on the basis of the existing image buffer; the memory buffer and the image buffer have the same timer to achieve a synchronous reduction display effect; Step 2, Receiving Echoes: The radar display and control system receives a new radial echo data A. Let the azimuth angle of the radial echo data A be α, and the echo intensity of the radial echo data A be H1. Step 3, Radial Echo Data A Fusion Cache: Read the echo intensity H0 of the radial echo data at azimuth angle α in the memory cache, and compare H0 with H1; when H1 > H0, superimpose the radial echo data A onto the azimuth angle α and cache it; Otherwise, radial echo data A will not be cached; Step 4, Image caching: Determine whether the user has performed any eccentricity or range change operations at the current moment; A. When the user performs either the eccentricity or range change operation, the image cache is cleared; then, radial echo data is read from the memory cache fused in step 3, and the read radial echo data is updated to the image cache. B. If the user does not perform any operation in eccentricity or range change, the radial echo data A received in step 2 will be directly updated to the image cache area. Step 5: Draw the wake: Based on the radial echo data in the image buffer area in Step 4, draw the radar echo wake image on the layer below the radar echo image.

2. The method for displaying echo wakes from dual-buffered navigation radar according to claim 1, characterized in that: It also includes step 6, displaying the trail in different display modes, which specifically includes the following steps: Step 6-1: Determine the display mode: Determine the current display mode of the interface; the display mode includes north-facing display mode and non-north-facing display mode; Step 6-2, Rotation: Rotate the radar echo wake image from Step 5 according to the display mode to facilitate the identification of target ships ahead; the specific rotation method is as follows: A. When the display mode is north-facing, the radar echo wake image in step 5 remains unchanged. B. When the display mode is not due north upward display mode, first use the radar center as the base point to synchronously rotate the radar echo image, radar echo wake image and non-radar image in the current display interface in step 5. Step 6-3, Offset: Let the coordinates of the display center before rotation be point O. After rotating with the radar center as the base point, the original display center rotates to point O1. Based on the distance from the original display center point O to the radar center and the rotation angle in step 6-2, calculate the latitude and longitude of point O1 to facilitate the offset of the latitude and longitude coordinate system.

3. The method for displaying echo wakes from dual-buffered navigation radar according to claim 2, characterized in that: It also includes step 7, displaying the wake under different motion modes, which specifically includes the following steps: Step 7-1: Determine the motion pattern: Based on the set motion pattern of the target, the motion pattern includes relative motion pattern and absolute motion pattern; where, relative motion pattern refers to the motion pattern of the target relative to the ship; absolute motion pattern refers to the motion pattern of the target relative to the ground. Step 7-2, Displaying Absolute Trail: When the motion mode is absolute motion mode, the trail displayed in step 5 or step 6 is an absolute trail; when the motion mode is relative motion mode, the trail displayed in step 5 or step 6 is a relative trail; when the motion mode is relative motion mode, the effect of displaying an absolute trail in relative motion mode needs to be achieved by reversing the movement of the trail.

4. The method for displaying echo wakes from dual-buffered navigation radar according to claim 3, characterized in that: In step 7-2, the method of reverse wake movement is as follows: First, calculate the direction and distance C of the target's movement relative to the ship; then, move the image cache of the relative wake in the opposite direction of the ship's heading by the same distance C to achieve the display effect of the absolute wake in the state of relative motion.

5. The method for displaying echo wakes from dual-buffered navigation radar according to claim 3, characterized in that: It also includes step 8, which repeats steps 2 to 7 to display the wake of the next new radial echo data.

6. The method for displaying echo wakes from dual-buffered navigation radar according to claim 1, characterized in that: In step 1, both the image cache and the memory cache are created based on the maximum length of the radial data and the maximum number of radial data.

7. The method for displaying echo wakes from dual-buffered navigation radar according to claim 1, characterized in that: In step 1, the time interval dTimer needs to be calculated based on the trail display time t selected by the user. The specific calculation formula is as follows: dTimer = t*60*1000 / 255; In the formula, dTimer is in milliseconds and t is in minutes.

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