JP4972471B2 - Radio wave propagation analyzer - Google Patents

Description

  The present invention relates to a radio wave propagation analyzing apparatus that performs radio wave propagation analysis between a radio wave transmitting vehicle and a radio wave receiving vehicle.

  In recent years, the field of use of wireless network technologies such as vehicle mutual information communication, mobile phones, and wireless LANs has expanded due to their usefulness.

  In general, a radio wave emitted from a transmission point of a radio wave such as a transmission antenna goes straight in a radial pattern around the transmission point. However, when there are obstacles (buildings, vehicles, etc.) beyond that, the radio waves are reflected, transmitted, and diffracted by the obstacles, spread in various directions, and attenuate.

  The above-mentioned radio wave propagation characteristics (reflection, transmission, diffraction, etc.) greatly affect the data communication performance of the wireless network system. Therefore, when manufacturing and selling products that include wireless network technology such as vehicle mutual information communication, mobile phones, and wireless LANs, how radio waves propagate in the target space as a pre-stage of manufacturing and sales. It is necessary to investigate how far radio waves can reach.

  Such a radio wave propagation characteristic is analyzed by computer simulation because it requires a large-scale device or requires a lot of labor and cost when measured using an experimental device or a prototype. Many techniques for propagation analysis are used.

  Such analysis methods include an electromagnetic field analysis method and a geometric optical method.

  In the electromagnetic field analysis method, Maxwell's electromagnetic field equation is solved by using, for example, an FDTD (Finite Difference Time Domain) method, and the electric field strength distribution is estimated based on the result. However, in this method, the calculation amount becomes enormous in the frequency band above the UHF band where the wavelength is shorter than the dimension of the model to be analyzed.

  The geometric optical method (ray tracing method) calculates electric field strength from trajectory information of a light beam transmitted from a transmission point and reaching a reception point, assuming that a radio wave is a geometric optical beam. The method of deriving the trajectory can be broadly classified into two methods: a mirror image point method (imaging method) and a ray launching method.

  In the mirror image point method, a reflection point is derived from a combination of a transmission point, a reception point, and all reflection surfaces to obtain a ray trajectory, and the ray trajectory can be obtained precisely. However, since the amount of calculation is proportional to the power of the number of reflections of the number of reflection surfaces, it becomes enormous when the shape of the analysis structure is complicated.

  In the ray launching method, light rays are discretely emitted from the transmission point at every transmission angle interval, the trajectory is sequentially tracked, and for each of the light rays that have reached the reception space defined around the reception point, A complex reception level is derived from propagation loss such as distance loss, polarization loss, and reflection loss, and the reception level is derived by phase-combining each ray. Therefore, since the amount of calculation processing is proportional to the number of reflecting surfaces, even when the shape of the analysis structure is complicated, it is small compared to the mirror image point method. However, since the reception point is defined in the reception space, the accuracy is poor compared to the mirror image point method that can accurately derive the ray trajectory.

  As a prior art of the above-mentioned radio wave propagation analysis, in Patent Document 1, a road is decomposed into straight sub-elements, a road width is calculated from data of a plurality of buildings, and at positions separated from each other by the road width around the sub-elements. An electric field intensity calculation device is disclosed in which a reflecting surface (two reflecting surfaces for one sub-element) is placed and ray tracing is performed using only the reflecting surface.

  Patent Document 2 discloses a radio wave propagation analysis apparatus that radiates a pseudo-ray only in a range where an obstacle and a reception source exist from a transmission source and performs radio wave propagation analysis.

  In Patent Document 3, a break point where the received electric field strength changes rapidly is identified in advance, and when the antenna height of the base station and the mobile station is sufficiently larger than the equivalent road surface height, calculation is performed using a different attenuation coefficient based on the break point. In other cases, there is disclosed a radio wave propagation estimation method that calculates using one type of attenuation coefficient.

  In Patent Document 4, a radio wave propagation path estimation method that generates a random number based on the type of an obstacle and determines whether or not to calculate a radio wave deduction amount and a radio vector vector direction change amount based on the random number is disclosed. It is disclosed.

This type of analysis method has a problem in that the amount of computation increases as the number of obstacles increases. However, if map data such as buildings and roads is simplified, the calculation accuracy is reduced, but the analysis accuracy is lowered. Therefore, it is desired that radio wave propagation analysis can be performed efficiently without affecting the accuracy of analysis.
Japanese Patent Application Laid-Open No. 9-119555 JP 2006-10349 A JP 2002-271275 A JP 2006-87038 A

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a technique for performing radio wave propagation analysis efficiently without affecting the analysis accuracy.

  In order to achieve the above object, the present invention adopts the following configuration.

  A radio wave propagation analysis apparatus according to the present invention is a radio wave propagation analysis apparatus that performs radio wave propagation analysis between a radio wave transmission vehicle and a radio wave reception vehicle, and stores map data including road information and obstacle information in advance. Based on the storage means, the road information, and the positions of the radio wave transmission vehicle and the radio wave reception vehicle, an area that is part of the map data and includes the radio wave transmission vehicle and the radio wave reception vehicle is used as an analysis area. Analysis area determining means for determining; and radio wave propagation analyzing means for performing radio wave propagation analysis based on information on obstacles in the analysis area and obstacles adjacent to the analysis area.

  In the radio wave propagation analyzing apparatus according to the present invention, an analysis area (a part of map data) to be analyzed is determined based on road information and the positions of a radio wave transmitting vehicle and a radio wave receiving vehicle, and the analysis area Radio wave propagation analysis is performed in consideration of only the obstacles inside and the obstacles adjacent to the analysis area. Thus, for example, if an area that greatly affects radio wave propagation analysis is set as an analysis area, efficient radio waves can be generated without affecting the analysis accuracy compared to performing radio wave propagation analysis on the entire map data. Propagation analysis can be performed.

The radio wave propagation analyzing apparatus according to the present invention may be configured to determine a plurality of routes from the radio wave transmitting vehicle to the radio wave receiving vehicle based on the road information, the position of the radio wave transmitting vehicle, and the position of the radio wave receiving vehicle. It is preferable that route search means for searching is further provided, and the analysis area determination means determines the route searched by the route search means as an analysis area. Since radio waves propagate mainly along roads, using only the route from the radio wave transmitting vehicle to the radio wave receiving vehicle as the path for radio waves makes it more efficient to propagate radio waves compared to using all roads as the path for radio waves. Analysis can be performed. Furthermore, since the radio wave traveling outside the route from the radio wave transmitting vehicle to the radio wave receiving vehicle does not affect the analysis, the analysis accuracy does not decrease.

  The analysis area determination means uses only the routes whose number of right / left turns and / or the route distance from the radio wave transmission vehicle to the radio wave reception vehicle are less than a predetermined threshold among the routes searched by the route search means as an analysis area. It is preferable to determine. A complicated route (a route with a lot of turns) or a route with a long distance from the radio transmission vehicle to the radio reception vehicle has a large number of reflections, transmissions, and diffractions of the radio wave. The electric field strength is weakened when it reaches. Such radio waves do not need to be considered because they do not have a significant effect on the analysis. Considering such radio waves leads to an increase in the amount of computation, so analysis accuracy can be improved by setting only the routes with a small number of right / left turns and the routes with short distances from the radio transmission vehicle to the radio reception vehicle as the analysis area. An efficient radio wave propagation analysis can be performed without lowering.

  It is preferable that the analysis area determination unit does not use a route including a part away from the radio wave receiving vehicle as a part of the route searched by the route search unit as the analysis area. A route that makes a detour leads to an increase in the number of right / left turns and an increase in the distance from the radio transmission vehicle to the radio reception vehicle. Therefore, efficient radio wave propagation analysis can be performed without reducing accuracy by not using such a route (a route that makes a detour) as an analysis area.

  It is preferable that the analysis area determination unit determines the road on which the radio wave transmitting vehicle travels and the road on which the radio wave reception vehicle travels as analysis areas. By performing radio wave propagation analysis using only roads where radio transmission vehicles and radio reception vehicles are traveling as radio wave paths, it is possible to perform radio wave propagation analysis far more efficiently than when all roads are radio wave paths. be able to.

  It is preferable that the analysis area determination means determines an area surrounded by a polygon having apexes of the positions of the radio wave transmission vehicle and the radio wave reception vehicle as an analysis area. Thereby, an analysis area can be determined easily. Furthermore, only obstacles in the area surrounded by polygons with the positions of the radio wave transmitting vehicle and radio wave receiving vehicle as vertices and obstacles adjacent to the polygons are considered in the radio wave propagation analysis, so they exist in all areas. Compared with considering all obstacles to be performed, it is possible to perform an efficient radio wave propagation analysis.

  Further, the present invention may be regarded as a radio wave propagation analysis apparatus having at least a part of the above means, or a radio wave propagation analysis method including at least a part of the above processing, or a radio wave propagation analysis for realizing such a method. It can also be understood as a program or a storage medium storing the program. Each of the above means and processes can be combined with each other as much as possible to constitute the present invention.

In the radio wave propagation analyzing apparatus according to the present invention, an analysis area (a part of map data) to be analyzed is determined based on road information and the positions of a radio wave transmitting vehicle and a radio wave receiving vehicle, and the analysis area Radio wave propagation analysis is performed in consideration of only the obstacles inside and the obstacles adjacent to the analysis area. Thus, for example, if an area that greatly affects radio wave propagation analysis is set as an analysis area, efficient radio waves can be generated without affecting the analysis accuracy compared to performing radio wave propagation analysis on the entire map data. Propagation analysis can be performed.

  Exemplary embodiments of the present invention will be described in detail below with reference to the drawings.

<Device configuration>
FIG. 1 is a block diagram showing a functional configuration of a radio wave propagation analyzing apparatus according to an embodiment of the present invention. This radio wave propagation analysis device is a device that performs radio wave propagation analysis (simulation of radio wave propagation) between a radio wave transmitting vehicle and a radio wave receiving vehicle. For example, in order to commercialize a vehicle equipped with a vehicle mutual information communication function, It is used for simulating whether the function operates normally (inspecting radio wave propagation characteristics). Note that this radio wave propagation analyzer is not limited to radio wave propagation characteristics between vehicles, but radio waves between various radio wave transmission sources and radio wave reception sources, such as between a person carrying a communication terminal and a vehicle equipped with a communication function. It can be used to investigate propagation characteristics.

  The radio wave propagation analysis apparatus includes a plurality of functional elements shown in FIG. 1, that is, a map data storage unit 11, an analysis area determination unit 12, a radio wave propagation analysis unit 13, a result storage unit 14, and a display unit 15. In the present embodiment, these functional elements are realized by an arithmetic processing unit of a computer executing software (program) and controlling hardware resources such as a hard disk, a memory, and a display as necessary. However, these functional elements may be configured by a dedicated chip.

  The map data storage unit 11 is a storage device that stores map data. As the storage device, any specific technique such as a nonvolatile memory or a hard disk may be applied. The map data includes road information (road position, shape (straight line, curved line, etc.), width, etc.) and obstacle (building, vehicle, etc.) information. The obstacle may be any object as long as it causes an obstacle (reflection, transmission, diffraction, etc.) of radio wave propagation. In the present embodiment, the position, size, and speed of vehicles and buildings are considered as obstacle information. Note that the vehicle stored in the map data includes a radio wave transmitting vehicle and a radio wave receiving vehicle.

  The analysis area determination unit 12 has a function of determining an analysis area to be analyzed in the radio wave propagation analysis. Specifically, the analysis area is determined based on the road information stored in the map data storage unit 11 and the positions of the radio wave transmitting vehicle and the radio wave receiving vehicle. The analysis area is a part of map data and includes the radio wave transmitting vehicle and the radio wave receiving vehicle.

  The radio wave propagation analysis unit 13 has a function of performing radio wave propagation analysis. Specifically, the radio wave propagation analysis is performed based on information on obstacles in the analysis area determined by the analysis area determination unit 12 and obstacles adjacent to the analysis area. Radio wave propagation analysis by the radio wave propagation analysis unit 13 is based on existing radio waves such as electromagnetic field analysis methods, geometric optical analysis methods, and methods using statistical formulas (methods using the Okumura-Kashiwa curve, Sakagami formula, Ikegami formula, etc.). Any technique of propagation analysis may be applied.

  The result storage unit 14 is a storage device that stores the result output from the radio wave propagation analysis unit 13. As the storage device, any specific technique such as a nonvolatile memory or a hard disk may be applied. Note that the result of the radio wave propagation analysis includes a received electric field strength of radio waves, a radio wave path, radio wave delay information, and the like.

  As the display unit 15, any specific technique such as a liquid crystal display may be applied.

<Radio wave propagation analysis function>
The function and processing flow of the radio wave propagation analyzer will be described with reference to the flowchart of FIG.

  When the radio wave propagation analysis process is activated, the analysis area determination unit 12 acquires map data from the map data storage unit 11 (step S11). An example of the map data in this embodiment is shown in FIG. The map data in FIG. 3 includes information on seven roads 31, 80 buildings 32, 30 vehicles 33, radio transmission vehicles 34, and radio reception vehicles 35. Note that the user can check the map data on the display unit 15 as necessary.

  Next, the analysis area determination unit 12 determines the analysis area based on the road information and the positions of the radio wave transmission vehicle and the radio wave reception vehicle (step S12).

  Then, the radio wave propagation analysis unit 13 performs a radio wave propagation analysis considering only the obstacle in the analysis area determined in step S12 and the obstacle adjacent to the analysis area (step S13).

  Next, the result of step S13 is stored in the result storage unit 14 (step S14). The user can check the stored result on the display unit 15.

  As described above, in the present embodiment, radio wave propagation analysis is performed in consideration of only the obstacle in the analysis area determined by the analysis area determination unit 12 and the obstacle adjacent to the analysis area. As a result, obstacles that exist in areas that do not significantly affect radio wave propagation analysis are not taken into account, so it is possible to perform efficient radio wave propagation analysis compared to radio wave propagation analysis that considers all obstacles in all areas. it can. Furthermore, by setting an area that greatly affects radio wave propagation analysis as an analysis area, efficient radio wave propagation analysis can be performed without degrading analysis accuracy.

<Analysis area determination processing>
Since radio waves propagate mainly along the road, it is considered that the path from the radio wave transmitting vehicle to the radio wave receiving vehicle becomes a path for the radio waves. Furthermore, it is also conceivable that the radio wave is reflected by an obstacle existing between the radio wave receiving vehicle and the radio wave transmitting vehicle. Therefore, in the analysis area determination process (step S12), a road surrounded by a polygon where the positions of the radio transmission vehicle and the radio reception vehicle are apexes (the analysis area determination process 1) where the radio transmission vehicle and the radio reception vehicle are present. One of (analysis area determination process 2) and a route from the radio wave transmission vehicle to the radio wave reception vehicle (analysis area determination process 3) is set as an analysis area. In other words, for the radio wave propagation analysis, it is sufficient to consider only obstacles in such an analysis area and obstacles adjacent to the analysis area.

  A specific example of the analysis area determination processes 1 to 3 will be described with reference to the flowcharts of FIGS. Note that any of the analysis area determination processes 1 to 3 may be used in step S12, and the radio wave propagation analysis apparatus may automatically select the analysis area determination process technique, or the user may select according to the purpose. May be.

<Analysis area determination process 1>
The flowchart in FIG. 4 shows a specific example of the analysis area determination process 1. Note that this processing method is performed when the road on which the radio wave transmission vehicle 34 travels and the road on which the radio wave reception vehicle 35 travels are the same, or the road on which the radio wave transmission vehicle 34 travels and the road on which the radio wave reception vehicle 35 travels. Effective when crossing.

  First, the analysis area determination unit 12 detects the road on which the radio wave transmitting vehicle travels and the road on which the radio wave receiving vehicle travels (step S21). In this embodiment, the road 71 and the road 72 shown in FIG. 7 are detected. The radio wave transmission vehicle 34 travels on the road 71, and the radio wave reception vehicle 35 travels on the road 72.

  Next, it is determined whether or not the roads detected in step S21 are the same (step S22). If they are the same (step S22; YES), the process proceeds to step S24. If they are not the same (step S22; NO), the process proceeds to step S23.

  In step S23, it is determined whether or not the detected roads intersect. When intersecting (step S23; YES), the process proceeds to step S24. When not intersecting (step S23; NO), all areas are set as analysis areas (step S25).

  In step S24, the analysis area determination unit 12 sets the road detected in step S21 as the analysis area. In the present embodiment, the road 71 and the road 72 are set as analysis areas (in the case where it is determined in step S22 that they are the same, one road is set as the analysis area). The analysis area may be all the roads included in the map data such as the road 71 and the road 72, or a part of the road 71 and the road 72 such as the road 81 and the road 82 shown in FIG. You may limit to.

  Therefore, the radio wave propagation analysis in the present embodiment is performed only on the vehicle traveling on the road 71 and the road 72, and on the building and the vehicle adjacent to the road 71 and the road 72 by the method of the analysis area determination process 1. It is performed in a limited manner (for example, radio wave propagation analysis considering only obstacles surrounded by a solid line 73 in FIG. 7). When the analysis area is the road 81 and the road 82, the radio wave propagation analysis considering only the obstacle surrounded by the dotted line 83 is performed.

<Analysis area determination process 2>
The flowchart in FIG. 5 shows a specific example of the analysis area determination process 2.

  First, the analysis area determination unit 12 forms a polygon having apexes at the position of the radio wave transmitting vehicle and the position of the radio wave receiving vehicle (step S31). In the present embodiment, a quadrangle 91 is formed with the position of the radio wave transmission vehicle 34 and the position of the radio wave reception vehicle 35 as diagonal positions (FIG. 9).

  Next, the analysis area determination unit 12 sets an area surrounded by the polygon formed in step S31 as an analysis area (step S32). In the present embodiment, an area surrounded by the rectangle 91 is an analysis area. The analysis area may be any polygon as long as it is not a rectangle such as the quadrangle 91 but a triangle, a parallelogram, a trapezoid, a pentagon, or the like.

  Therefore, the analysis area can be easily determined by the method of the analysis area determination processing 2, and the radio wave propagation analysis is adjacent to the building and vehicle existing in the area surrounded by the rectangle 91 and the rectangle 91. This is performed only for buildings and vehicles (for example, radio wave propagation analysis considering only obstacles surrounded by a solid line 92 in FIG. 9).

<Analysis area determination process 3>
The analysis area determination process 3 can be performed when the radio wave propagation analysis apparatus further includes the route search unit 16. FIG. 10 is a block diagram showing a functional configuration of the radio wave propagation analysis apparatus including the route search unit 16.

  The route search unit 16 has a function of searching for a route between vehicles based on road information. For the route search processing, any technology of existing route search processing such as route search processing using the Dijkstra method may be applied. Note that the route search unit 16 in the present embodiment searches for a plurality of routes from the radio wave transmission vehicle to the radio wave reception vehicle based on road information, the position of the radio wave transmission vehicle, and the position of the radio wave reception vehicle.

  The flowchart in FIG. 6 shows a specific example of the analysis area determination process 3.

  First, the route search unit 16 searches for a plurality of routes from the radio wave transmitting vehicle to the radio wave receiving vehicle (step S41). In the present embodiment, it is assumed that routes 111 to 113 in FIG. 11 have been searched.

  Next, the analysis area determination unit 12 sets the route searched in step S41 as an analysis area (step S42). In the present embodiment, the paths 111 to 113 are set as analysis areas.

  Therefore, in the radio wave propagation analysis in the present embodiment, the obstacle is limited to only vehicles traveling on the routes 111 to 113 and buildings and vehicles adjacent to the routes 111 to 113 by the method of the analysis area determination process 3. (For example, radio wave propagation analysis considering only obstacles surrounded by a solid line 114 in FIG. 11).

  In the analysis area determination process 3, all the searched routes are set as the analysis area. However, the number of right / left turns or the route distance from the radio transmission vehicle to the radio reception vehicle, or both the number of right / left turns and the route distance are predetermined. Only routes that are less than or equal to the threshold may be used as the analysis area (routes that have a large number of turns or long distances and a route that has a long distance cause an increase in the number of reflections with obstacles. You do n’t need to consider it because it does n’t reach, or it ’s very weak when you reach it.) The threshold value is set in advance by the user.

  FIG. 12 is an example of a route search result (for the sake of simplicity, the radio wave transmission vehicle 121 and the radio wave reception vehicle 122 are shown in FIG. 12, and other obstacles are not shown). The number of right / left turns and the route distance of the route 123a are “1 time, 1.3 km”, and the number of right / left turns and the route distance of the route 123b are “2 times, 0.8 km”. The number of left turns and the route distance are “4 times, 1 km”, and the number of right and left turns and the route distance of the route 123d are “5 times, 1.5 km”. When no threshold is set, four routes 123a to 123d are set as analysis areas. By setting the threshold value of the number of right / left turns to “twice”, only the route 123a and the route 123b are set as the analysis area. By setting the route distance threshold to “1 km”, only the route 123b and the route 123c are set as the analysis area, and by setting the right / left turn count and the route distance threshold to “2 times, 1 km”, only the route 123b is set. Is the analysis area.

  In this way, by setting the right / left turn count and the threshold of the route distance, only the route suitable for the passage of the radio wave can be set as the analysis area, so that it is possible to perform the efficient radio wave propagation analysis without reducing the accuracy. it can.

  Note that the analysis area determination process may not include a route including a part away from the radio wave receiving vehicle as a part of the route as an analysis area (in addition, if there is only a route including a part away from the radio wave receiving vehicle, It may be obtained by the method of Routes that include parts that are part of the route away from the vehicle that receives the radio waves will lead to an increase in the number of left / right turns and the route distance. Analysis can be performed.

  As described above, the analysis area determination processing according to the present embodiment has three methods of analysis area determination processing 1 to 3, and any method can be used to reduce the number of obstacles to be analyzed. Therefore, it is possible to perform an efficient radio wave propagation analysis as compared to performing a radio wave propagation analysis considering all obstacles in all areas. The analysis area determination process is not limited to the above three methods, and any analysis method may be used as long as it is a method for determining an area that is a part of the entire area and includes the radio wave transmission vehicle and the radio wave reception vehicle. A technique may be used.

  Although the road information is not described in detail in the present embodiment, the road information may be two-dimensional road information or road information including a three-dimensional shape. The radio wave propagation analysis apparatus according to this embodiment can efficiently perform radio wave propagation analysis regardless of the type of road information.

  In the present embodiment, road information and information on obstacles (including radio wave transmitting vehicles and radio wave receiving vehicles) are stored in the map data storage unit 11, but only road information is stored in the map data storage unit 11. May be. In that case, the information such as the building and the vehicle may be input by the user or may be stored in another storage device. In this case, a storage device different from the map data storage unit 11 corresponds to the map data storage means of the present invention.

  In this embodiment, the format of the map data is not described. However, the map data can be any data format such as image data, character data, and numerical data as long as it can acquire road information and obstacle information. It may be in the form. The user can change the contents of the map data while confirming the map data on the display unit 15.

  In the analysis area determination processing 1 of the present embodiment, when the road on which the radio wave transmitting vehicle runs and the road on which the radio wave receiving vehicle runs are not the same and do not intersect, the entire area is set as the analysis area. However, in this case, another analysis area determination method may be used, or it may be determined that communication is impossible, and the subsequent processing may be stopped. Thereby, efficient radio wave propagation analysis can be performed.

FIG. 1 is a block diagram showing a functional configuration of the radio wave propagation analyzing apparatus. FIG. 2 is a flowchart showing the flow of processing of the radio wave propagation analyzer. FIG. 3 is a diagram illustrating an example of map data. FIG. 4 is a flowchart showing the flow of the analysis area determination process 1. FIG. 5 is a flowchart showing the flow of the analysis area determination process 2. FIG. 6 is a flowchart showing the flow of the analysis area determination process 3. FIG. 7 is a diagram illustrating an example of an analysis area in the analysis area determination process 1. FIG. 8 is a diagram illustrating an example of an analysis area in the analysis area determination process 1. FIG. 9 is a diagram illustrating an example of an analysis area in the analysis area determination process 2. FIG. 10 is a block diagram showing a functional configuration of the radio wave propagation analysis apparatus including the route search unit 16. FIG. 11 is a diagram illustrating an example of an analysis area in the analysis area determination process 3. FIG. 12 is a diagram illustrating an example of a route search processing result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Map data memory | storage part 12 Analysis area determination part 13 Radio wave propagation analysis part 14 Result memory | storage part 15 Display part 16 Route search part 31 Road 32 Building 33 Vehicle 34 Radio wave transmission vehicle 35 Radio wave reception vehicle 71, 72 Road 81, 82 Road 111, 112, 113 route 121 radio wave transmitting vehicle 122 radio wave receiving vehicle 123a-123d route

Claims (4)

A radio wave propagation analysis device that performs radio wave propagation analysis between a radio wave transmission vehicle and a radio wave reception vehicle,
Map data storage means for storing map data including road information and obstacle information in advance;
A route search means for searching a plurality of routes from the radio wave transmission vehicle to the radio wave reception vehicle based on the road information, the position of the radio wave transmission vehicle, and the position of the radio wave reception vehicle;
Analysis area determination means for determining, as an analysis area, only a route whose number of right / left turns and / or route distance from the radio wave transmission vehicle to the radio wave reception vehicle is not more than a predetermined threshold among the routes searched by the route search means; ,
Radio wave propagation analysis means for performing radio wave propagation analysis based on information on obstacles in the analysis area and obstacles adjacent to the analysis area;
Equipped with a,
When the road on which the radio wave transmitting vehicle runs and the road on which the radio wave receiving vehicle runs are not the same and do not intersect, the radio wave propagation analyzing means uses the entire area of the map data as an analysis area. Radio wave propagation analysis device that performs radio wave propagation analysis or does not perform radio wave propagation analysis. 2. The radio wave propagation analysis apparatus according to claim 1 , wherein the analysis area determination unit does not use, as an analysis area, a route including a part away from the radio wave receiving vehicle in a part of the route searched by the route search unit. Computer
A step of storing in advance in the storage means map data including information of the road information and the obstacle,
Searching for a plurality of routes from the radio wave transmission vehicle to the radio wave reception vehicle based on the road information, the position of the radio wave transmission vehicle, and the position of the radio wave reception vehicle;
Determining, as an analysis area, only a route whose number of right / left turns and / or route distance from the radio wave transmitting vehicle to the radio wave receiving vehicle is a predetermined threshold or less among the searched routes ;
Performing radio wave propagation analysis based on information on obstacles in the analysis area and obstacles adjacent to the analysis area ;
A radio wave propagation analysis method for performing
In the step of performing the radio wave propagation analysis when the road on which the radio wave transmitting vehicle and the road on which the radio wave receiving vehicle are traveling are not the same and do not intersect, the entire area of the map data is analyzed. Radio wave propagation analysis method in which radio wave propagation analysis is performed as an area or radio wave propagation analysis is not performed . On the computer,
Preliminarily storing map data including road information and obstacle information in storage means;
Searching for a plurality of routes from the radio wave transmission vehicle to the radio wave reception vehicle based on the road information, the position of the radio wave transmission vehicle, and the position of the radio wave reception vehicle;
Determining, as an analysis area, only a route whose number of right / left turns and / or route distance from the radio wave transmitting vehicle to the radio wave receiving vehicle is a predetermined threshold or less among the searched routes ;
Performing radio wave propagation analysis based on information on obstacles in the analysis area and obstacles adjacent to the analysis area;
A radio wave propagation analysis program for executing
In the step of performing the radio wave propagation analysis when the road on which the radio wave transmitting vehicle and the road on which the radio wave receiving vehicle are traveling are not the same and do not intersect, the entire area of the map data is analyzed. A radio wave propagation analysis program in which radio wave propagation analysis is performed as an area or radio wave propagation analysis is not performed .

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