Navigation method and system for mobile port machinery based on environmental perception

Abstract

The present invention discloses a method and system for navigating mobile port machinery based on environmental perception, which relates to the field of navigation technology. A plurality of mechanical devices that require navigation are identified as a plurality of target devices, and a projection chain is set between the corresponding plurality of target devices and a port navigation model. A plurality of measurement points are set corresponding to the target devices, and environmental information is constructed in real time to obtain a regional model. Based on the projection chain, the regional model is integrated into the port navigation model in real time, and the navigation routes of all target devices are adjusted in real time according to the port navigation model. The present invention can update the port environment in a timely and clear manner using the projection chain to collect information about the surrounding environment from the target devices. It can adjust the routes of multiple devices in real time according to the overall port environment, thus avoiding congestion of mobile machinery due to information errors, affecting cargo transshipment at the port, and better ensuring the orderly operation of port equipment.

Description

Technical Field

[0001] The present invention relates to the field of navigation technology, and in particular to a port mobile machinery navigation method and system based on environment perception. Background Art

[0002] With the advancement of globalization and the booming international trade, ports, as crucial nodes in logistics and transportation, are facing increasing demands for operational efficiency and safety. To improve port operational efficiency, transport navigation for port equipment is a crucial step. Currently, due to the large scale of ports, equipment moves and handles cargo independently, resulting in partially or completely identical routes. When obstacles appear on these routes, it's difficult to accurately and promptly communicate environmental perception to other equipment, making it difficult to ensure timely navigation adjustments for port equipment. Summary of the Invention

[0003] The purpose of the present invention is to provide a port mobile machinery navigation method and system based on environment perception to solve the deficiencies in the background technology.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for navigating mobile port machinery based on environmental perception, comprising the following steps:

[0005] Identify multiple mechanical equipment that need to be navigated as multiple target equipment, and set up projection chains between the corresponding multiple target equipment and the port navigation model;

[0006] Set up multiple measurement points corresponding to the target device, collect environmental information around the target device according to the measurement points, and construct the environmental information in real time to obtain a regional model;

[0007] Based on the projection chain, the regional model is integrated into the port navigation model in real time, and the navigation routes of all target devices are adjusted in real time according to the port navigation model.

[0008] In a preferred embodiment, the step of determining a plurality of mechanical devices requiring navigation as a plurality of target devices and setting a projection link between the corresponding plurality of target devices and the port navigation model includes:

[0009] Acquire port environment information, wherein the port environment information includes port fixed information and port geographic information, and perform three-dimensional construction based on the port environment information to obtain a port navigation model;

[0010] A plurality of mechanical devices that need to be navigated are respectively used as a plurality of target devices, and corresponding construction groups are configured for the plurality of target devices, wherein the construction group includes a construction area and a data conversion area corresponding to the construction area;

[0011] A corresponding connection relationship between the data conversion area and the port navigation model is established, and the construction group and the corresponding connection relationship between the data conversion area and the port navigation model are used as a projection chain.

[0012] In a preferred embodiment, the step of using multiple mechanical devices that need to be navigated as multiple target devices and configuring corresponding building groups for the multiple target devices includes:

[0013] The target device is used as the center and the range within the preset radius is used as the environmental perception area. Multiple contour points corresponding to the environmental perception area of the target device are set as the construction area.

[0014] A projection space is set corresponding to the construction area, wherein the projection space includes an upper space, a first side space, and a second side space, and a plurality of projection points are set in the projection space to obtain a data conversion area;

[0015] A connection relationship between the construction area and the data conversion area is established, and the contour points are projected and connected with the projection points in the upper space, the first side space, and the second side space respectively to obtain a construction group.

[0016] In a preferred embodiment, the step of establishing a corresponding connection relationship between the data conversion area and the port navigation model and using the construction of the cluster and the corresponding connection relationship between the data conversion area and the port navigation model as a projection chain includes:

[0017] configuring corresponding data bearing surfaces for the upper space, the first side space, and the second side space, respectively, and establishing connection relationships between a plurality of projection points in the upper space, the first side space, and the second side space and the corresponding data bearing surfaces;

[0018] Set a fixed point for the target device and a random point in the port navigation model. Set the range within the preset radius around the random point as the update area. The update area and the construction area have the same range. Establish a corresponding connection relationship between the fixed point and the random point.

[0019] The projection space of the data conversion area is connected with the fixed point to obtain the connection relationship between the projection space of the data conversion area and the random point in the port navigation model.

[0020] In a preferred embodiment, the step of setting a plurality of measurement points corresponding to the target device, collecting environmental information around the target device according to the measurement points, and constructing the environmental information in real time to obtain a regional model includes:

[0021] Set up multiple measurement points for each target device, and collect real-time device information and real-time geographic information around the target device as environmental information based on the measurement points;

[0022] A three-dimensional model of the environmental information within the environmental perception area of the target device is constructed as a regional model.

[0023] In a preferred embodiment, the step of integrating the regional model into the port navigation model in real time based on the projection chain and adjusting the navigation routes of all target devices in real time according to the port navigation model includes:

[0024] The regional model is stored in the construction area, and the contour of the regional model is attached through the contour points in the construction area;

[0025] Obtaining position shape diagrams of the projection points in the upper space, the first side space, and the second side space by projecting and connecting the projection points in the upper space, the first side space, and the second side space with the contour points;

[0026] The position shape diagram is stored in a corresponding data bearing surface, and the corresponding data bearing surface is transmitted to a fixed point through the upper space, the first side space, and the second side space, and then transmitted to a random point through the fixed point;

[0027] By restoring the data bearing surfaces corresponding to the upper space, the first side space and the second side space into a regional model at random, and updating the corresponding update area in the port navigation model;

[0028] The navigation routes of all target equipment are adjusted in real time according to the updated port navigation model.

[0029] The present invention also provides a port mobile machinery navigation system based on environmental perception, comprising:

[0030] A setting module is used to determine multiple mechanical equipment that needs to be navigated as multiple target equipment, and to set up projection chains between the multiple target equipment and the port navigation model;

[0031] The construction module is connected to the setting module and is used to set multiple measurement points corresponding to the target device, collect environmental information around the target device according to the measurement points, and construct the environmental information in real time to obtain a regional model;

[0032] The adjustment module is connected to the construction module and is used to integrate the regional model into the port navigation model in real time based on the projection chain, and adjust the navigation routes of all target devices in real time according to the port navigation model.

[0033] In the above technical solution, the technical effects and advantages provided by the present invention are:

[0034] The present invention can update the port environment in a timely and clear manner through the projection chain the information of the surrounding environment collected by the target equipment, and can adjust the routes of multiple devices in real time according to the overall environment of the port, avoiding congestion of mobile machinery due to information errors, affecting the cargo transshipment of the port, and better ensuring the orderly operation of port equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments described in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0036] Figure 1 Flow chart of the method of the present invention.

[0037] Figure 2 This is a system block diagram of the present invention. DETAILED DESCRIPTION

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0039] Example 1, please refer to Figure 1 As shown, the environment-aware port mobile machinery navigation method of this embodiment includes the following steps:

[0040] S1. Determine multiple mechanical equipment that needs to be navigated as multiple target equipment, and set up projection chains between the multiple target equipment and the port navigation model;

[0041] S2. Set multiple measurement points corresponding to the target device, collect environmental information around the target device according to the measurement points, and construct the environmental information in real time to obtain a regional model;

[0042] S3. Based on the projection chain, the regional model is integrated into the port navigation model in real time, and the navigation routes of all target devices are adjusted in real time according to the port navigation model.

[0043] In one embodiment, the step S1 of determining a plurality of mechanical devices that need to be navigated as a plurality of target devices and setting up a projection link between the corresponding plurality of target devices and the port navigation model includes:

[0044] S11. Acquire port environment information, wherein the port environment information includes port fixed information and port geographic information, and perform three-dimensional construction based on the port environment information to obtain a port navigation model;

[0045] S12, taking multiple mechanical devices that need to be navigated as multiple target devices, and configuring corresponding construction groups for the multiple target devices, wherein the construction group includes a construction area and a data conversion area corresponding to the construction area;

[0046] S13, establishing a corresponding connection relationship between the data conversion area and the port navigation model, and using the construction group and the corresponding connection relationship between the data conversion area and the port navigation model as a projection chain;

[0047] As described in steps S11-S13 above, first, the port fixed information and port geographic information are obtained. The port fixed information here includes fixed cargo stacking locations, port equipment for long-term storage of cargo, and fixed working locations. The port geographic information includes the port's range size information and geographic shape information. Then, the port geographic information is three-dimensionally constructed to obtain a port environment model. The port fixed information in the port is three-dimensionally constructed and added to the port environment model to obtain a port navigation model. The port navigation model is used as a reference for subsequent equipment navigation and avoidance decision analysis. Then, corresponding construction groups are configured for each of the multiple target devices. Then, a corresponding connection relationship is established between the data conversion area and the port navigation model. The corresponding connection relationship between the construction group and the data conversion area and the port navigation model is used as a projection chain. Through the projection chain, the environment perceived by the target device can be constructed into the port navigation model in real time. In this way, the port navigation model can be updated in real time, and the navigation of the multiple target devices can be adjusted according to the real-time port navigation model.

[0048] In one embodiment, the step S12 of using the plurality of mechanical devices that need to be navigated as a plurality of target devices and configuring corresponding building groups for the plurality of target devices includes:

[0049] S121, taking the target device as the center and defining a range within a preset radius as an environmental sensing area, and setting a plurality of contour points corresponding to the environmental sensing area of the target device as a construction area;

[0050] S122. Setting a projection space corresponding to the construction area, wherein the projection space includes an upper space, a first side space, and a second side space, and setting a plurality of projection points in the projection space to obtain a data conversion area;

[0051] S123, establishing a connection relationship between the construction area and the data conversion area, projecting and connecting the contour points with the projection points in the upper space, the first side space, and the second side space, respectively, to obtain a construction clique;

[0052] In one embodiment, the step S13 of establishing a corresponding connection relationship between the data conversion area and the port navigation model and using the construction group and the corresponding connection relationship between the data conversion area and the port navigation model as a projection chain includes:

[0053] S131, configuring corresponding data bearing surfaces for the upper space, the first side space, and the second side space, respectively, and establishing connection relationships between a plurality of projection points in the upper space, the first side space, and the second side space and the corresponding data bearing surfaces;

[0054] S132. Set a fixed point for the target device and a random point in the port navigation model. Set the area within a preset radius around the random point as the update area. The update area and the construction area have the same range. Establish a corresponding connection relationship between the fixed point and the random point.

[0055] S133, connecting the projection space of the data conversion area with the fixed point to obtain a connection relationship between the projection space of the data conversion area and the random point in the port navigation model;

[0056] As described in the above steps S12 and S13, in order to update the surrounding environmental information subsequently collected by the target device to the port navigation model in real time, first, the target device is used as the center and the range within the preset radius is used as the environmental perception area. The environmental perception area is a virtual range within the preset radius around the target device. Here, the environmental perception area is represented by virtuality as a data space, and a plurality of contour points are set corresponding to the environmental perception area of the target device as a construction area. Here, the environmental perception area is used as the area where the target device subsequently collects the surrounding environmental information. A plurality of contour points are set in the area, wherein the contour points are network nodes, which can be attached to the outer contour of the virtual three-dimensional model inside the subsequent construction area, and then a projection space is set corresponding to the construction area, wherein the projection space includes an upper space, a first side space and a second side space, and the upper space, the first side space and the second side space are all represented by a data layer, and the data layer is a data space. Then, multiple projection points are set in the upper space, the first side space and the second side space respectively to obtain a data conversion area. The projection point can be connected to the contour point in a projection connection manner, which means that the projection point and the contour point are connected in a one-to-one straight line. This is equivalent to attaching the contour point to the outer contour of the virtual three-dimensional model inside the construction area, and then projecting the virtual three-dimensional model inside the construction area upward and to the left and right sides. In this way, the virtual three-dimensional model inside the construction area can be converted into a plane. The planes at three angles can represent the virtual three-dimensional model inside the construction area. In this way, the surrounding environmental information collected by the target device can be constructed to obtain a virtual three-dimensional model inside the construction area for rapid transmission and real-time update to the port navigation model. The contour points are projected and connected with the projection points in the upper space, the first side space and the second side space respectively. The projection connection is a straight line orthographic projection connection between the contour point and the projection point to obtain a construction group.After the construction group is constructed on the target device, the construction is continued on the connection between the port navigation model and the construction group. First, the corresponding data bearing surfaces are configured for the upper space, the first side space and the second side space respectively. The data bearing surface is a data carrier, which is used to carry the shape of the projection point after the projection point and the contour point are connected on the corresponding upper space, the first side space and the second side space. The data bearing surface is used to transmit the shape of the projection point after the projection point and the contour point are connected to the port navigation model to update the port navigation model in real time. The corresponding target device is set with a fixed point, which is the port of the corresponding target device. The random point is set in the port navigation model, which is the corresponding point in the port navigation model. The port of the target device, the port navigation model as a data carrier can load the random point. There is a positional relationship between the fixed point and the random point. The random point can move with the fixed point. The range within the preset radius with the random point as the center is used as the update area. The range of the update area is the same as the construction area. A corresponding connection relationship is established between the fixed point and the random point. The projection space of the data conversion area is connected to the fixed point to obtain the connection relationship between the projection space of the data conversion area and the random point in the port navigation model. The upper space, the first side space and the second side space in the projection space are all data layers (databases). In this way, the data carrying surface can be transmitted to the fixed point through the projection space, and then transmitted to the random point through the fixed point.

[0057] In one embodiment, the step S2 of setting a plurality of measurement points corresponding to the target device, collecting environmental information around the target device according to the measurement points, and constructing the environmental information in real time to obtain a regional model includes:

[0058] S21, setting multiple measurement points corresponding to multiple target devices respectively, and collecting real-time device information and real-time geographic information around the target devices as environmental information according to the measurement points;

[0059] S22, constructing a three-dimensional model of the environmental information within the environmental perception area of the target device as a regional model;

[0060] As described in steps S21 and S22 above, multiple measurement points are set for each target device. The measurement points include various sensors such as lidar, camera, and millimeter-wave radar to increase the dimensionality of environmental information measurement, effectively expand the detection range, and enhance environmental robustness. Real-time device information and real-time geographic information around the target device are collected as environmental information based on the measurement points. After obtaining the environmental information, the environmental information is three-dimensionally constructed within the environmental perception area of the target device to obtain a regional model. This regional model is a real-time model collected by the target device.

[0061] In one embodiment, the step S3 of integrating the regional model into the port navigation model in real time based on the projection chain and adjusting the navigation routes of all target devices in real time according to the port navigation model includes:

[0062] S31, storing the regional model in the construction area, and attaching the contour of the regional model through the contour points in the construction area;

[0063] S32, obtaining position shape diagrams of the projection points in the upper space, the first side space, and the second side space by projectively connecting the projection points in the upper space, the first side space, and the second side space with the contour points;

[0064] S33, storing the position shape graph in the corresponding data bearing surface, transmitting the corresponding data bearing surface to the fixed point through the upper space, the first side space, and the second side space, and transmitting the fixed point to the random point;

[0065] S34, restoring the data bearing surfaces corresponding to the upper space, the first side space, and the second side space into a regional model by point-by-point, and updating the corresponding update area in the port navigation model;

[0066] S35. Adjusting the navigation routes of all target devices in real time according to the updated port navigation model;

[0067] As described in the above steps S31-S35, the construction area is represented by the data space and multiple contour points are set. The regional model is stored in the construction area, and the contour of the regional model is attached through the contour points in the construction area. According to the principle of three-dimensional model three-dimensional plane graphics obtained by projection: the position shape diagram of the projection points in the upper space, the first side space and the second side space is obtained by the projection connection between the projection points and the contour points. Then, the position shape diagram is attached to the data carrying surface for transmission. By collecting and transmitting the plane, the efficiency of data transmission can be guaranteed, thereby improving the real-time performance of data transmission. In this way, the regional model collected when the target device is in one position can be updated to the port guide in a timely manner. In the navigation model, the target device is constantly moving and will move to another position the next moment. If the transmission is not efficient enough, the transmission of the regional model will be delayed and may cause the position of the regional model update in the port navigation model to deviate. At the same time, the transmitted data is relatively simple as a plane image, which can ensure the security of data transmission. The simplicity of the data means that the transmission process is efficient and not prone to data confusion and loss. First, the corresponding data bearing surface is transmitted to the fixed point through the upper space, the first side space and the second side space, and then transmitted to the random point through the fixed point. After receiving the information, the random point restores the data bearing surface corresponding to the upper space, the first side space and the second side space into the regional model through the random point and updates the model of the corresponding update area in the port navigation model. New, the restoration of the three-dimensional model here is based on the plane projection map of at least three sides, and the entire port navigation model can be updated in real time through the perception of the environment by multiple target devices. The route of the target device can be better planned through the update of the entire port navigation model. For example, the nearest route between the starting point and the destination is given priority. However, when obstacles are found in the nearest route through the collection and model and update of the environmental perception of other target devices, the route of the target device can be adjusted to another nearest route that does not pass through the obstructed route. The navigation routes of all target devices are adjusted in real time according to the updated port navigation model, and the information of the surrounding environment collected by the target device can be transmitted through the projection chain. Timely updating of the port environment can adjust the routes of multiple devices in real time according to the overall environment of the port, avoid equipment blockage due to information errors, affect the flow of cargo at the port, and better ensure the orderly operation of port equipment. In order to ensure the accuracy of environmental perception, multiple measurement points are set for each target device, so the data is different. Direct transmission of information is prone to confusion. Therefore, in order to ensure the accuracy of environmental perception, multiple measurement points are set. In order to ensure that the data is not easily confused, a regional model is constructed in the projection chain of the target device and the regional model is simplified for transmission, which not only ensures the accuracy of environmental perception, but also simplifies transmission to ensure efficiency, and has a good port navigation model update effect.Better adaptive routing of all target equipment within the port.

[0068] Example 2, please refer to Figure 2 As shown, the port mobile machinery navigation system based on environment perception described in this embodiment includes:

[0069] A setting module is used to determine multiple mechanical equipment that needs to be navigated as multiple target equipment, and to set up projection chains between the multiple target equipment and the port navigation model;

[0070] The construction module is connected to the setting module and is used to set multiple measurement points corresponding to the target device, collect environmental information around the target device according to the measurement points, and construct the environmental information in real time to obtain a regional model;

[0071] The adjustment module is connected to the construction module and is used to integrate the regional model into the port navigation model in real time based on the projection chain, and adjust the navigation routes of all target devices in real time according to the port navigation model;

[0072] Mobile machinery is a common practice in large-scale dry bulk cargo loading and unloading operations. However, the use of mobile machinery in ports presents several common characteristics in safety management: First, individual operations are highly arbitrary, making safety management and control difficult; second, the operating environment is highly variable, making safety pre-control difficult. Most work sites rely on human-machine and machine-machine collaboration, with frequent machinery movement and rapidly changing operating environments. This places high demands on drivers and presents significant challenges in understanding the surrounding safety environment. Safety hazards are constantly present and changing, making it difficult to gain a timely and clear understanding of changes in the port environment. Multiple target devices are connected to the port navigation model, which transmits real-time port data to the target devices and allows for direct control of the target devices through the port navigation model.

[0073] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A port mobile machinery navigation method based on environmental perception, characterized in that: The following steps are involved: Identify multiple mechanical equipment that need to be navigated as multiple target equipment, and set up projection chains between the corresponding multiple target equipment and the port navigation model; The step of determining a plurality of mechanical devices requiring navigation as a plurality of target devices and setting a projection link between the corresponding plurality of target devices and the port navigation model includes: Acquire port environment information, wherein the port environment information includes port fixed information and port geographic information, and perform three-dimensional construction based on the port environment information to obtain a port navigation model; A plurality of mechanical devices that need to be navigated are respectively used as a plurality of target devices, and corresponding construction groups are configured for the plurality of target devices, wherein the construction group includes a construction area and a data conversion area corresponding to the construction area; The step of using the plurality of mechanical devices that need to be navigated as a plurality of target devices and configuring corresponding construction groups for the plurality of target devices includes: The target device is used as the center and the range within the preset radius is used as the environmental perception area. Multiple contour points corresponding to the environmental perception area of the target device are set as the construction area. A projection space is set corresponding to the construction area, wherein the projection space includes an upper space, a first side space, and a second side space, and a plurality of projection points are set in the projection space to obtain a data conversion area; Establishing a connection relationship between the construction area and the data conversion area, projecting and connecting the contour points with the projection points in the upper space, the first side space, and the second side space, respectively, to obtain a construction group; Establishing a corresponding connection relationship between the data conversion area and the port navigation model, and using the construction group and the corresponding connection relationship between the data conversion area and the port navigation model as a projection chain; Set up multiple measurement points corresponding to the target device, collect environmental information around the target device according to the measurement points, and construct the environmental information in real time to obtain a regional model; Based on the projection chain, the regional model is integrated into the port navigation model in real time, and the navigation routes of all target devices are adjusted in real time according to the port navigation model.

2. The method for navigation of mobile port machinery based on environmental perception according to claim 1, characterized in that: The step of establishing a corresponding connection relationship between the data conversion area and the port navigation model and using the construction group and the corresponding connection relationship between the data conversion area and the port navigation model as a projection chain includes: configuring corresponding data bearing surfaces for the upper space, the first side space, and the second side space, respectively, and establishing connection relationships between a plurality of projection points in the upper space, the first side space, and the second side space and the corresponding data bearing surfaces; Set a fixed point for the target device and a random point in the port navigation model. Set the range within the preset radius around the random point as the update area. The update area and the construction area have the same range. Establish a corresponding connection relationship between the fixed point and the random point. The projection space of the data conversion area is connected with the fixed point to obtain the connection relationship between the projection space of the data conversion area and the random point in the port navigation model.

3. The method for navigation of mobile port machinery based on environmental perception according to claim 1, characterized in that: The step of setting a plurality of measurement points corresponding to the target device, collecting environmental information around the target device according to the measurement points, and constructing the environmental information in real time to obtain a regional model includes: Set up multiple measurement points for each target device, and collect real-time device information and real-time geographic information around the target device as environmental information based on the measurement points; A three-dimensional model of the environmental information within the environmental perception area of the target device is constructed as a regional model.

4. The method for navigation of mobile port machinery based on environmental perception according to claim 1, characterized in that: The step of integrating the regional model into the port navigation model in real time based on the projection chain and adjusting the navigation routes of all target devices in real time according to the port navigation model includes: The regional model is stored in the construction area, and the contour of the regional model is attached through the contour points in the construction area; Obtaining position shape diagrams of the projection points in the upper space, the first side space, and the second side space by projecting and connecting the projection points in the upper space, the first side space, and the second side space with the contour points; The position shape diagram is stored in a corresponding data bearing surface, and the corresponding data bearing surface is transmitted to a fixed point through the upper space, the first side space, and the second side space, and then transmitted to a random point through the fixed point; By restoring the data bearing surfaces corresponding to the upper space, the first side space and the second side space into a regional model at random, and updating the corresponding update area in the port navigation model; The navigation routes of all target equipment are adjusted in real time according to the updated port navigation model.

5. A port mobile machinery navigation system based on environment perception, used to implement the port mobile machinery navigation method based on environment perception according to any one of claims 1 to 4, characterized in that: include: A setting module is used to determine multiple mechanical equipment that needs to be navigated as multiple target equipment, and to set up projection chains between the multiple target equipment and the port navigation model; The construction module is connected to the setting module and is used to set multiple measurement points corresponding to the target device, collect environmental information around the target device according to the measurement points, and construct the environmental information in real time to obtain a regional model; The adjustment module is connected to the construction module and is used to integrate the regional model into the port navigation model in real time based on the projection chain, and adjust the navigation routes of all target devices in real time according to the port navigation model.

Images