CN115164892B - Visual navigation method and device for airborne radar - Google Patents

Abstract

The invention discloses an airborne radar visual navigation method and device, and belongs to the technical field of signal processing. The invention combines the terrain detection data and the digital map, synthesizes the view field with the view field angle of the driver, provides the navigation function of route planning according to the synthesized view field information, can independently decide to carry out intelligent risk avoidance, has the characteristics of miniaturization and light design, fully considers convenience and mobility, adopts high-density circuit design, is constructed in a highly integrated manner, can be obtained by flexibly combining the modules according to the needs, adopts a parallelization and general computing platform for comprehensive treatment, can be expanded according to task requirements, has good upgrading and maintenance performances, and is worthy of popularization and use.

Description

A method and device for visual navigation of airborne radar

Technical Field

The present invention relates to the technical field of signal processing, and in particular to an airborne radar visual navigation method and device.

Background Art

Commonly used aircraft often need to perform ultra-low-altitude flights to perform missions. Due to the changeable terrain, obstacles such as mountains, forests, buildings, power lines, and towers may pose a danger to flight at any time; the weather is complex, and weather conditions such as thunderstorms, low clouds, wind shear, and turbulence may directly threaten flight safety.

This requires that the aircraft's (carrier's) airborne radar be able to detect targets on the flight path under any adverse weather conditions, warn pilots of various obstacles that endanger flight safety within the warning range, and be able to penetrate rain, snow, smoke and dust to detect potential threats to aircraft safety, including towers, buildings, terrain and power lines. It can send warning signals in a timely manner within a safe distance to guide weather avoidance, low-altitude terrain avoidance and collision avoidance flights. At the same time, according to the distribution of dangerous weather areas and weather targets on the route, the aircraft's flight route is adjusted to output safe route data. This requires the airborne radar to have the ability of visual navigation.

In order to meet the requirements of airborne radar visual navigation, the present invention proposes an airborne radar visual navigation method and device.

Summary of the invention

The technical problem to be solved by the present invention is: how to solve the problem of airborne radar visualization navigation. An airborne radar visualization navigation method is provided. The method uses basic data to generate a three-dimensional environment, fuses meteorological targets with the three-dimensional environment to generate a three-dimensional vision, and after identifying obstacles, selects the corresponding model to fuse with the three-dimensional environment to form a vision fusion. The flight path is dynamically planned according to the positioning information and obstacle information, thereby navigating and guiding the aircraft and displaying it in three dimensions.

The present invention solves the above technical problems through the following technical solutions, and the present invention comprises the following steps:

S1: When the aircraft is performing a flight mission, the existing elevation digital model and digital orthophoto data are used to generate a three-dimensional environment;

S2: Detect meteorological target information through airborne radar, and fuse the meteorological target information with the three-dimensional environment to generate a three-dimensional visual synthesis signal output;

S3: Detect obstacles in real time through airborne radar and identify them. According to the identification results, select the corresponding model from the pre-built obstacle model library and fuse it with the three-dimensional environment to form visual fusion;

S4: Dynamically plan the aircraft path according to the positioning information and obstacle information, and finally perform three-dimensional navigation guidance and display on the aircraft based on the positioning information and path planning.

Furthermore, in step S1, the three-dimensional environment is constructed by processing the elevation digital model and the digital orthophoto map obtained by satellite remote sensing and aerial remote sensing to generate rasterized terrain data and surface texture. After projection transformation and texture mapping, the surface texture is transformed to obtain a three-dimensional terrain database, that is, a three-dimensional environment.

Furthermore, the specific process of step S2 includes scanning the cloud layer using an airborne weather radar detector, and reconstructing and synthesizing the cloud layer in three dimensions based on the weather radar detection data. When reconstructing and synthesizing the weather radar data in real time, the weather radar data is first preprocessed to convert the data stored in the polar coordinate format into data in a rectangular coordinate system, and then the three-dimensional environmental data field established using the cube weighted interpolation method is integrated, and the three-dimensional visual signal of the weather radar data is synthesized and output through a surface mesh algorithm.

Furthermore, in step S3, a modeling software is used to create an obstacle model with LOD characteristics, thereby achieving the modeling of the obstacle.

Furthermore, the obstacles include buildings, large trees, electric poles, windmills, and power towers.

Furthermore, in step S3, when the airborne radar is working, the integrated processor (integrated processing module) sequentially scans in the search sector according to the control parameters generated by the integrated display and control system (integrated display and control module), transmits excitation signals, performs antenna radiation, and completes the transmission beam in space to detect obstacles, establishes SAR imaging with the detected obstacle echo information, and compares it with the image information in the original obstacle typical target library of the radar, thereby realizing the identification of targets such as power lines, towers, buildings, clouds and rain.

Furthermore, in the step S3, during fusion, the obstacle model information is reprojected based on the real-time positioning information of the aircraft, the obstacle distance and angle measurement information, and the collinear equation, so as to realize the fusion display of the obstacle model and the three-dimensional environment information and form the synthetic vision three-dimensional environment information.

Furthermore, when performing dynamic trajectory planning for an aircraft, the three-dimensional trajectory planning is divided into two parts, namely the horizontal channel and the vertical channel; when performing horizontal channel trajectory planning, it is completed on the DEM contour line, and the Dijkstra algorithm is used to expand outward layer by layer from the starting point to the end point to calculate the shortest path from one node to all other nodes; in the vertical channel trajectory planning, the terrain following mechanism is used, and the flight safety corridor is planned taking into account the maneuverability of the aircraft and the elevation value of the DEM; finally, the horizontal channel and the vertical channel safety corridor are intersected to form a three-dimensional flight trajectory dynamic planning.

Furthermore, in step S4, the three-dimensional navigation guidance display uses enhanced synthetic vision technology to comprehensively display the aircraft flight status information, three-dimensional environment, obstacles, flight channels and safety prompts on the display.

The present invention also provides an airborne radar visualization navigation device, which adopts the above method to perform three-dimensional navigation guidance and display work on an aircraft, including: an antenna module, an integrated processing module, an inertial navigation module, a servo module, and an integrated display and control module. The integrated processing module receives control commands from the integrated display and control module, controls the antenna module in real time, and transmits and receives airborne radar signals; and controls the servo module in real time, and controls the steering of the airborne radar antenna through the servo module; the integrated processing module simultaneously receives inertial navigation information of the aircraft obtained by the inertial navigation module, and sends the inertial navigation information to the integrated display and control module.

Furthermore, the antenna module is connected to the integrated processing module via an optical fiber, the integrated processing module is connected to the inertial navigation module via a SAM cable, the integrated processing module is connected to the servo module via a SAM cable, and the integrated processing module is connected to the integrated display and control module via a network.

Compared with the prior art, the present invention has the following advantages: the airborne radar visualization navigation method and device match and synthesize terrain detection data with digital maps, and the synthetic field of view is based on the driver's field of view. At the same time, a route planning and navigation function is provided according to the synthesized field of view information, and autonomous decision-making can be made for intelligent risk avoidance. The device has the characteristics of miniaturization and lightweight design, and fully considers convenience and mobility. The module adopts high-density circuit design and high-integration construction, and the scale can be obtained through flexible combination of modules as needed. The comprehensive processing of the device adopts a parallel and general computing platform, which can be expanded according to task requirements, and has good upgrade and maintenance performance, and is worthy of popularization and use.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a flow chart of an airborne radar visual navigation method according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of the structure of a visual navigation device according to an embodiment of the present invention.

DETAILED DESCRIPTION

The following is a detailed description of an embodiment of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

As shown in FIG1 , this embodiment provides a technical solution: an airborne radar visual navigation method, comprising the following steps:

S1: When the aircraft is performing a flight mission, the existing basic data such as DEM and DOM are first used to generate a three-dimensional environment;

S2: Detect meteorological target information through airborne radar, and fuse the meteorological target information with the three-dimensional environment to generate a three-dimensional visual synthesis signal output;

S3: Detect obstacles in real time through airborne radar and identify them. According to the identification results, select the corresponding model from the pre-built obstacle model library (trees, high-voltage lines/towers, buildings, etc.) and fuse it with the three-dimensional environment to form visual fusion;

S4: Dynamically plan the aircraft path according to the positioning information and obstacle information, and finally perform three-dimensional navigation guidance and display on the aircraft based on the positioning information and path planning.

In this embodiment, in step S1, the three-dimensional environment is constructed by using a digital elevation model (DEM) and a digital orthophoto map (DOM) obtained by satellite remote sensing and aerial remote sensing, and the DEM and DOM are processed to generate rasterized terrain data and surface textures. The surface textures are projected and texture mapped to obtain a three-dimensional terrain database;

In this embodiment, according to actual needs, DEM and DOM can be obtained from professional surveying and mapping departments or commercial surveying and mapping companies, and appropriate areas and corresponding resolutions can be selected according to actual needs. The obtained data is converted into rasterized terrain data composed of triangular facets. The surface texture is generated using the DOM corresponding to the DEM area, and the texels in the texture space are mapped to the pixels in the rasterized space. The actual display size of the texels is determined by the texture resolution and the rotation and scaling during the transformation process, thereby generating a vivid and realistic terrain model.

In this embodiment, in step S2, the cloud layer is scanned by an airborne weather radar detector, and the cloud layer is reconstructed and synthesized in three dimensions based on the weather radar detection data. When the weather radar data is reconstructed and synthesized in real time, the weather radar data is first preprocessed to convert the data stored in the polar coordinate format into data in a rectangular coordinate system, and then the three-dimensional environmental data field established by the cube weighted interpolation method is integrated, and the three-dimensional visual signal of the weather radar data is synthesized and output through the surface mesh algorithm.

In the present embodiment, in the step S3, the obstacle database modeling mainly involves steps such as data preparation, determining the model hierarchy, building the model, and texture mapping. The obstacle model with LOD (Levels of Detail) characteristics is created using Creator modeling software. LOD technology is a display technology for the detail level of the model at different levels. When modeling, if the level of LOD is lower, the model is simpler, and if the level of LOD is higher, the model is more realistic. Models constructed using different LOD levels can save memory space, achieve the best visual effect, and ensure the smoothness of scene rendering. Therefore, the use of LOD technology can greatly improve the efficiency of model display. The software corresponding to the visual navigation method in the present embodiment uses LOD technology to model obstacles such as buildings, trees, electric poles, windmills, and electric towers.

In this embodiment, in step S3, obstacle detection and fusion is that when the airborne radar is working, the processor sequentially scans in the search sector according to the control parameters generated by the integrated display and control system, transmits excitation signals, performs antenna radiation, and completes the transmission beam in space to detect obstacles, and establishes SAR imaging with the detected obstacle echo information, and compares it with the image information in the original obstacle typical target library of the radar, so as to realize the recognition of targets such as power lines, towers, buildings, clouds and rain. According to the recognition results, a suitable obstacle model is selected from the obstacle database and fused with the three-dimensional terrain database. During fusion, according to the real-time positioning information of the carrier (aircraft), the obstacle ranging and angle measurement information, and the collinear equation is used to reproject the obstacle model information, so as to realize the fusion display of the obstacle model and the three-dimensional environment information, and form the synthetic visual three-dimensional environment information.

In the present embodiment, in the step S4, the path planning is to dynamically plan the real-time route of the carrier aircraft according to the real-time positioning information, terrain information, obstacle information and the maneuverability of the carrier aircraft on the basis of obtaining the environmental obstacle information, and the three-dimensional track planning is divided into two parts, namely the horizontal channel and the vertical channel. When the horizontal channel track planning is performed, it is completed on the DEM contour line, and the Dijkstra algorithm is used to calculate the shortest path from one node to all other nodes, which is expanded outward layer by layer with the starting point as the center until it is expanded to the end point. In the vertical channel track planning, the flight safety corridor is planned mainly based on the mechanism of terrain following, and the maneuverability of the aircraft and the elevation value of the DEM are considered. Finally, the horizontal channel and the vertical channel safety corridor are intersected to form a three-dimensional flight track dynamic planning to ensure the safety of the carrier aircraft (aircraft) in the flight engineering, and the track is displayed in real time on the three-dimensional environment, and the flight safety is prompted with different colors, and the carrier aircraft path is dynamically planned.

In this embodiment, in step S4, the three-dimensional navigation guidance display uses enhanced synthetic vision technology to comprehensively display the aircraft flight status information, three-dimensional environment, obstacles, flight channels, and safety prompts on the display, thereby realizing the three-dimensional navigation guidance display of the aircraft. The three-dimensional guidance display interface includes a flight instrument display interface, a safe flight channel prompt, a three-dimensional scene, etc.

As shown in FIG2 , this embodiment also provides an airborne radar visualization navigation device, which uses the above method to perform three-dimensional navigation guidance and display work on an aircraft, including an antenna module (including the antenna array surface in FIG2 ), an integrated processing module (i.e., an integrated processing machine in FIG2 ), an inertial navigation module (for obtaining inertial navigation information), a servo module (i.e., a servo system in FIG2 ), and an integrated display and control module (i.e., an integrated display system in FIG2 );

In this embodiment, the integrated processing module is used to receive control commands from the integrated display and control module, control the antenna module in real time, transmit and receive airborne radar signals; and control the servo module in real time to control the steering of the airborne radar antenna.

In this embodiment, the integrated processing module also simultaneously receives the inertial navigation information of the aircraft acquired by the inertial navigation module, and sends the inertial navigation information to the integrated display and control module.

In this embodiment, the antenna module and the integrated processing module are connected via optical fiber, the integrated processing module and the inertial navigation module are connected via a SAM cable, the integrated processing module and the servo module are connected via a SAM cable, and the integrated processing module and the integrated display and control module are connected via a network.

To sum up, the airborne radar visualization navigation method and device of the above-mentioned embodiment match and synthesize terrain detection data with digital maps. The synthetic field of view is based on the driver's field of view. At the same time, it provides route planning and navigation functions according to the synthesized field of view information, and can make autonomous decisions for intelligent risk avoidance. The device has the characteristics of miniaturization and lightweight design, and fully considers convenience and mobility. The module adopts high-density circuit design and high-integration construction, and the scale can be obtained through flexible combination of modules as needed. The comprehensive processing of the device adopts a parallel and general computing platform, which can be expanded according to task requirements, and has good upgrade and maintenance performance, and is worthy of promotion and use.

Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims (10)

1. An airborne radar visual navigation method, characterized in that it comprises the following steps: S1: When the aircraft is performing a flight mission, the existing elevation digital model and digital orthophoto data are used to generate a three-dimensional environment; S2: Detect meteorological target information through airborne radar, and fuse the meteorological target information with the three-dimensional environment to generate a three-dimensional visual synthesis signal output; S3: Detect obstacles in real time through airborne radar and identify them. According to the identification results, select the corresponding model from the pre-built obstacle model library and fuse it with the three-dimensional environment to form visual fusion; S4: Dynamically plan the aircraft path according to the positioning information and obstacle information, and finally perform three-dimensional navigation guidance and display on the aircraft based on the positioning information and path planning. 2. According to the airborne radar visualization navigation method described in claim 1, it is characterized in that: in the step S1, the three-dimensional environment is constructed by using the elevation digital model and digital orthophoto map obtained by satellite remote sensing and aerial remote sensing, and the elevation digital model and the digital orthophoto map are processed to generate rasterized terrain data and surface texture. After the surface texture is projected and texture mapped, a three-dimensional terrain database, that is, a three-dimensional environment, is obtained. 3. According to the airborne radar visualization navigation method described in claim 2, it is characterized in that: the cloud layer is scanned by an airborne weather radar detector, and the cloud layer is three-dimensionally reconstructed and synthesized based on the weather radar detection data; when the weather radar data is reconstructed and synthesized in real time, the weather radar data is first preprocessed to convert the data stored in the polar coordinate format into data in a rectangular coordinate system, and then the three-dimensional environmental data field established by the cube weighted interpolation method is integrated, and the three-dimensional visual signal of the weather radar data is synthesized and output through a surface mesh algorithm. 4. The airborne radar visualization navigation method according to claim 3 is characterized in that: in the step S3, a modeling software is used to create an obstacle model with LOD characteristics, thereby realizing the modeling of the obstacle. 5. The method for visual navigation of an airborne radar according to claim 4 is characterized in that: in step S3, when the airborne radar is working, it sequentially scans in the search sector, transmits an excitation signal, performs antenna radiation and completes the transmission beam in space to detect obstacles, establishes SAR imaging with the detected obstacle echo information, and compares it with the image information in the original obstacle typical target library of the radar, thereby realizing the identification of power lines, towers, buildings and cloud and rain targets. 6. According to claim 5, an airborne radar visualization navigation method is characterized in that: in the step S3, during fusion, the obstacle model information is reprojected based on the real-time positioning information of the aircraft, the obstacle ranging and angle measurement information, and the collinear equation is used to realize the fusion display of the obstacle model and the three-dimensional environment information to form a synthetic visual three-dimensional environment information. 7. An airborne radar visualization navigation method according to claim 6 is characterized in that: in the step S4, when the aircraft is performing dynamic trajectory planning, the three-dimensional trajectory planning is divided into two parts, namely the horizontal channel and the vertical channel; when performing horizontal channel trajectory planning, it is completed on the DEM contour line, and the Dijkstra algorithm is used to expand outward layer by layer from the starting point to the end point, and the shortest path from one node to all other nodes is calculated; in the vertical channel trajectory planning, the flight safety corridor is planned based on the mechanism of terrain following and considering the maneuverability of the aircraft and the elevation value of the DEM; finally, the horizontal channel and the vertical channel safety corridor are intersected to form a three-dimensional flight trajectory dynamic planning. 8. According to the airborne radar visualization navigation method of claim 7, it is characterized in that: in the step S4, the three-dimensional navigation guidance display uses enhanced synthetic vision technology to comprehensively display the aircraft flight status information, three-dimensional environment, obstacles, flight channels and safety prompts on the display. 9. An airborne radar visualization navigation device, characterized in that the method described in any one of claims 1 to 8 is used to perform three-dimensional navigation guidance and display on an aircraft, comprising: an antenna module, an integrated processing module, an inertial navigation module, a servo module, and an integrated display and control module. The integrated processing module receives control commands from the integrated display and control module, controls the antenna module in real time, and transmits and receives airborne radar signals; and controls the servo module in real time, and controls the steering of the airborne radar antenna through the servo module; the integrated processing module simultaneously receives inertial navigation information of the aircraft obtained by the inertial navigation module, and sends the inertial navigation information to the integrated display and control module. 10. An airborne radar visualization navigation device according to claim 9, characterized in that: the antenna module and the integrated processing module are connected via optical fiber, the integrated processing module and the inertial navigation module are connected via a SAM cable, the integrated processing module and the servo module are connected via a SAM cable, and the integrated processing module and the integrated display and control module are connected via a network.