JP6616813B2 - Arithmetic apparatus, arithmetic method, arithmetic program thereof, and recording medium - Google Patents

Description

  The present invention relates to an arithmetic device for calculating a radius of curvature, an arithmetic method, an arithmetic program thereof, and a recording medium on which the arithmetic program is recorded.

  2. Description of the Related Art Conventionally, a technique for creating a map used in a navigation system for performing vehicle navigation has been developed. As one of the techniques, there is a technique described in Patent Document 1. Japanese Patent Application Laid-Open No. 2004-228561 discloses that an arc portion calculation (approximation) process is performed from point cloud data of a running locus by a least square method.

JP 2014-160064 A

  By the way, in the technique described in Patent Document 1, an arc is calculated based on point group data including the arc portion within the target range, and whether or not the correlation coefficient is within a predetermined range, that is, the approximation accuracy. Whether the degree is greater than or equal to a predetermined degree, and when the correlation coefficient is within a predetermined range, the arc is specified by whether or not the correlation coefficient with the previously calculated arc matches. . For this reason, there is a problem that the load of the arc portion specifying process is large and it takes time to calculate the arc.

  Therefore, in order to solve the above-described problem, the present invention can easily specify an arc and calculate its radius of curvature by a method different from Patent Document 1, and an arithmetic method, An object of the present invention is to provide the arithmetic program and a recording medium on which the arithmetic program is recorded.

  In order to solve the above-described problem, an arithmetic device according to one embodiment of the present invention provides a combination indicating a combination of position information of a vehicle and direction information indicating the direction of the vehicle at the position indicated by the position information. Based on the combination information, an acquisition unit that acquires a plurality of information, a specific unit that specifies a section in which the ratio between the travel distance of the vehicle and the amount of change in the direction information of the vehicle is constant, and the specific unit has a constant ratio And a radius of curvature calculating section for calculating the radius of curvature.

  In order to solve the above-described problem, a calculation method according to an aspect of the present invention includes a combination that indicates a combination of vehicle position information and direction information that indicates the direction of the vehicle at the position indicated by the position information. An acquisition step for acquiring a plurality of information, a specific step for specifying a section in which the ratio between the travel distance of the vehicle and the amount of change in the direction information of the vehicle is constant based on the combination information, and the ratio is constant in the specific step A radius of curvature calculation step of calculating the radius of curvature as a zone having a constant radius of curvature.

  In order to solve the above problem, a calculation program according to an aspect of the present invention provides a combination indicating a combination of vehicle position information and direction information indicating the direction of the vehicle at a position indicated by the position information. Based on the acquisition function that acquires a plurality of information and the combination information, the specific function that specifies the section in which the ratio of the travel distance of the vehicle and the change amount of the direction information of the vehicle is constant, and the specific function has a constant ratio The section that is specified as is a section having a constant curvature radius, and the curvature radius calculation function for calculating the curvature radius is realized.

  In the arithmetic device, using two pieces of combination information whose position information is adjacent to each other, a ratio between a distance between the position information indicated by the two pieces of combination information and a change amount of direction information in the two pieces of combination information is calculated. A ratio calculating unit may be further provided, and the specifying unit may specify a section in which the ratio calculated by the ratio calculating unit is constant.

  In the above arithmetic device, the acquisition unit acquires the position information of the host vehicle acquired by the position information acquisition system mounted on the vehicle transmitted from the vehicle as position information, and is mounted on the vehicle transmitted from the vehicle. It is good also as acquiring the own vehicle direction information acquired by as direction information.

  In the above arithmetic device, the acquisition unit further includes a direction information calculation unit that acquires points plotted on the map by the user as position information and calculates direction information at each plotted point based on the plurality of plotted points. It is good as well.

  In the above arithmetic device, when the distance is ΔL, the amount of change is ΔH, the radius of curvature is R, and the circumference is Π, the radius of curvature calculator may calculate the radius of curvature using the following equation (1). Good.

  The arithmetic device according to one embodiment of the present invention can calculate the curvature radius after specifying a section in which the curvature radius is constant. Therefore, for example, the radius of curvature can be calculated easily and accurately in the trajectory on which the vehicle has traveled on the map.

It is a block diagram which shows the function structural example of an arithmetic unit. It is a flowchart which shows the operation example which concerns on the curvature radius calculation of a calculating device. It is the figure which showed the concept for calculating the curvature with respect to the path | route which the vehicle drive | worked, and the said path | route. It is an example of the graph which shows the relationship between the variation | change_quantity of a travel distance, and the variation | change_quantity of a heading difference. It is a flowchart which shows the other operation example which concerns on the curvature radius calculation of a calculating device. It is a flowchart which shows the other operation example which concerns on the curvature radius calculation of a calculating device. It is a block diagram which shows the function structural example of an arithmetic unit.

  Hereinafter, an arithmetic device according to an embodiment of the present invention will be described in detail with reference to the drawings.

<Embodiment>
<Configuration>
The arithmetic device according to one embodiment of the present invention (corresponding to 100 in FIG. 1) is a combination that indicates a combination of vehicle position information and direction information that indicates the direction of the vehicle at the position indicated by the position information. An acquisition unit (corresponding to 101 in FIG. 1) that acquires a plurality of information, and a specifying unit that identifies a section in which the ratio between the travel distance of the vehicle and the amount of change in the direction information of the vehicle is constant based on the combination information (Corresponding to 105 in FIG. 1) Is provided.

  FIG. 1 is a block diagram illustrating a functional configuration example of the arithmetic device 100. As shown in FIG. 1, the arithmetic device 100 for calculating a radius of curvature indicating the degree of bending of a road or the like includes an acquisition unit 101, a reception unit 102, an output unit 103, a storage unit 104, and a CPU 105. .

  The acquisition unit 101 is a communication interface having a function of communicating with an external device and exchanging information. The acquisition unit 101 can acquire, for example, travel information (combination information) from an external device. The travel information is information indicating at least a travel route on which the vehicle has traveled. More specifically, the travel information indicates position information indicating the position of the vehicle, a time when the position information is measured, and a direction of the vehicle when the position information is acquired. Information. The position information indicating the position of the vehicle is, for example, information on longitude and latitude measured by a positioning system implemented by a GPS (Global Positioning System), a GNSS (Global Navigation Satellite System), or the like mounted on the vehicle. The time when the position information is measured is the time when positioning is performed by the positioning system. For example, the GPS time or the time of a clock mounted on the vehicle can be used. The direction information indicating the direction of the vehicle is information indicating which direction the front of the vehicle is facing, and for example, information measured by an orientation sensor, a gyro sensor, or the like can be used. The direction information may be referred to as a heading value as a direction in which the vehicle head is facing. The external device may be, for example, a sensor having a communication function mounted on a vehicle, and collects probe information by using probe information (probe traffic information) acquired from the vehicle as travel information, It may be a distribution system. The acquisition unit 101 transmits various types of acquired information to the CPU 105.

  The receiving unit 102 has a function of receiving an input from an operator of the arithmetic device 100 and transmitting the input to the CPU 105. The accepting unit 102 can accept, for example, plot point information indicating one point on the map from the operator. The plot point information is information indicating the position (longitude and latitude) on the map. The accepting unit 102 can be realized by, for example, a hardware key provided in the arithmetic device 100, a soft key such as a touch key, or the like. The accepting unit 102 transmits the accepted plot point information to the CPU 105.

  The output unit 103 has a function of outputting instructed data to an external device in accordance with an instruction from the CPU 105. The output unit 103 outputs, for example, the radius of curvature calculated by the CPU 105, map information indicating a range where the curvature of the arc is constant on the map, and the like. The output unit 103 may be realized by outputting to a monitor or the like provided in the arithmetic device 100. The monitor may be an external monitor connected to the arithmetic device 100.

  The storage unit 104 is a recording medium that stores various types of data including various programs and map information necessary for the operation of the arithmetic device 100. The storage unit 104 is realized by, for example, an HDD (Hard Disc Drive), an SSD (Solid State Drive), or the like. The storage unit 104 stores travel information acquired by the acquisition unit 101 and plot point information received by the reception unit 102.

  The CPU 105 is a processor that executes processing to be executed by the arithmetic device 100 using programs and various data stored in the storage unit 104. The CPU 105 has a function of calculating the radius of curvature of the arc drawn by the travel locus based on the travel information acquired by the acquisition unit 101. Further, the CPU 105 may have a function of calculating a curvature radius of a curve obtained by connecting a plurality of plot points on the map received by the receiving unit 102 from the operator.

  The CPU 105 calculates the distance ΔL between the two pieces of traveling information using the two pieces of traveling information (combination information) whose position information is adjacent to each other (GPS time is continuous), and calculates the direction of each of the two pieces of traveling information. It functions as a ratio calculation unit that calculates a change amount ΔH of information and calculates ΔL / ΔH that is the ratio. Here, the change amount ΔH of the direction information can be calculated as an angle between the direction indicated by one of the two pieces of travel information and the direction indicated by the other. Note that the direction information change amount ΔH may be referred to as a heading difference.

  Further, the CPU 105 functions as a specifying unit that specifies a section in which the calculated ratio is constant. The CPU 105 identifies a section where the calculated ratio is constant as a section having the same curvature radius.

  And CPU105 functions as a curvature radius calculation part which calculates the curvature radius of the area where the specified ratio becomes constant from the following formula (2) using the circumference ratio Π.

  Further, the CPU 105 may function as a direction information calculation unit that calculates direction information at each plot point based on the plot points on the map received by the reception unit 102 from the operator.

  The above is the configuration of the arithmetic device 100.

<Operation>
From here, operation | movement of the arithmetic unit 100 is demonstrated. FIG. 2 is a flowchart showing a process for calculating the curvature radius by accepting travel information from a vehicle actually traveling by the arithmetic device 100.

  As shown in FIG. 2, the acquisition unit 101 of the arithmetic device 100 obtains GPS time, position information indicating the position of the vehicle, and a heading value (direction information) indicating the direction of the vehicle from the measurement vehicle that outputs the travel information. Are obtained as combination information (step S201). The acquisition unit 101 transmits the acquired combination information to the CPU 105.

  CPU105 calculates distance (DELTA) L between positional information with respect to each of two pairs of combination information with which GPS time is continuous (position information is adjacent) about the several combination information which the acquisition part 101 acquired (step S202). ).

  For the plurality of combination information acquired by the acquisition unit 101, the CPU 105 determines the difference in heading value, that is, the amount of change in direction information, for each pair of two combination information with consecutive GPS times (position information is adjacent). ΔH is calculated (step S203).

  Thereafter, the CPU 105 calculates a ratio ΔL / ΔH between the calculated distance ΔL between the position information and the change amount ΔH of the direction information (step S204).

  The CPU 105 identifies a section where the calculated ratio ΔL / ΔH is constant within an error range as a section where the radius of curvature is constant on the route traveled by the measurement vehicle indicated by the travel information (step S205).

  CPU105 calculates the curvature radius R of the identified area based on Formula (2) mentioned above.

  Thereby, the arithmetic unit 100 can calculate the curvature radius after specifying the section having the same curvature radius.

<Specific example>
Here, a specific example of specifying a section in which the measurement vehicle travels on the road and the ratio between the travel distance and the direction change amount is constant and the radius of curvature at that time will be described.

  FIG. 3 shows an example in which the measurement vehicle 320 travels on the road 310 along the route indicated by the travel locus 330. In FIG. 3, it is assumed that the measurement vehicle 320 measures position information and direction information at each black circle on the travel locus 330.

  As shown in FIG. 3, using the combination information that is a combination of the vehicle position information output at each black circle position and the direction information indicating the vehicle direction, the arithmetic device 100 is a section in which the curvature radius is constant. And the radius of curvature of the section is calculated.

  Here, a distance ΔL between position information indicated by two pieces of traveling information and a change amount (heading difference) ΔH between direction information will be described. With reference to a partially enlarged view of FIG. 3, the distance ΔL between the point P311 and the point P312 that have acquired adjacent traveling information on the traveling route and the change amount ΔH will be described.

  As shown in FIG. 3, the distance ΔL between the point P311 and the point P312 can be calculated based on the respective position information. That is, since information on the longitude and latitude of each of the two points can be obtained, ΔL can be calculated as the distance between the two points. This can also acquire the travel distance that the measurement vehicle 320 actually traveled. The travel distance acquired from the measurement vehicle 320 is more accurate ΔL, but since it can be approximated by a straight line distance ΔL between the point P311 and the point P312 by calculation, the straight line distance is calculated as ΔL here. To do.

  And at the point P311, the measurement vehicle 320 faces the direction shown by the arrow D311 and it is assumed that the direction can be acquired as the direction information. Similarly, at the point P312, the measurement vehicle 320 faces the direction indicated by the arrow D312 and it is assumed that the direction can be acquired as direction information. At this time, the amount of change in direction information can be calculated as the amount of change in angle in this direction. That is, the angle formed by the arrow D311a indicating the same direction as the arrow D311 in FIG. 3 and the arrow D312a indicating the same direction as the arrow D312 can be calculated as the change amount ΔH.

  The arithmetic device 100 calculates ΔL and ΔH for each point (black circle) at which position information is measured as shown in FIG. 3 and between two points adjacent to each other.

  The arithmetic device 100 can specify a section where the calculated ratio of ΔL and ΔH is constant as a constant curvature radius section where the curvature radius is constant (same). The section where the radius of curvature is constant can be specified based on the ratio calculated between the points, but as an image, as shown in FIG. 4, the horizontal axis represents the cumulative travel distance, and the vertical axis represents The cumulative heading difference is taken and a graph 401 in which the distance in each position information and the heading difference are plotted is created. The graph 401 appears as an interval in which the slope of the graph 401 is constant.

  Each point shown in FIG. 4 corresponds to each point shown in FIG. 3, and points P301, P302, P303, and P304 in FIG. 3 respectively correspond to points P301, P302, P303, and P304 shown in FIG. As can be seen from FIG. 4, for example, the slope of the graph 401 is substantially constant from P301 to P302, so the CPU 105 identifies this section as a section having a constant curvature radius. Further, for example, since the slope of the graph 401 is substantially constant from P303 to P304, the CPU 105 identifies the section between P303 and P304 as a section having a constant curvature radius.

  Then, after specifying a section in which the radius of curvature is constant, the arithmetic device 100 calculates, for example, a radius of curvature R1 for the traveling locus from P301 to P302 and a radius of curvature R2 for the traveling locus from P303 to P304. be able to.

<Modification 1>
In the above, using the travel information (combination information) acquired from the vehicle, the range in which the ratio of the travel distance and the heading difference is constant, that is, the curvature of the arc is assumed to be constant, and the arc of the specified range is calculated. The technique of doing was shown. However, in calculating the curvature radius, the curvature radius may be calculated using information other than the traveling information. Here, a method is shown in which the operator calculates the radius of curvature using the points plotted on the map. Hereinafter, the operation of the arithmetic device 100 will be described with reference to the flowchart shown in FIG.

  FIG. 5 is a flowchart showing the operation of calculating the radius of curvature of the locus drawn by the operator when the operator plots the point on the map.

  For example, the arithmetic device 100 outputs a map from the output unit 103. In other words, the map is displayed on the monitor. The operator looks at the displayed map and inputs (plots) a point as a measurement point on the road of the map via the reception unit 102, for example (step S501). That is, the operator inputs the position of the black circle shown in FIG.

  Since the displayed map is associated with longitude and latitude information, the CPU 105 of the arithmetic device 100 acquires the longitude and latitude of the input position on the map as position information of the travel information (step S502). ).

  The CPU 105 calculates the distance ΔL between the points that are plotted and are adjacent to each other as described above (step S503).

  Next, the CPU 105 calculates a heading value (direction information) for each plotted point (step S504). As the direction information, between adjacent points, the direction in which the vehicle travels, that is, a line segment connecting one point (start point side) to the other point (end point side) of the two points is indicated. The direction may be used as direction information, or an approximate curve obtained from the plotted points may be calculated, and the tangential direction at the plotted points of the approximate curve may be used as the direction information.

  In this way, using the position information acquired in step S502 and the heading value (direction information) acquired in step S504, the arithmetic device 100 identifies a section where the radius of curvature is constant and calculates the radius of curvature. (Step S505). That is, the processing from step S203 to S206 in FIG. 2 is executed.

  As described above, even when the actual measurement value is not acquired from the measurement vehicle 320, the curvature radius of the road can be calculated.

<Modification 2>
In the above embodiment and the first modification, the distance between two adjacent points and the ratio of the heading difference between the two points are calculated, and the section where the radius of curvature is constant is determined using the ratio. It was decided. In this case, there is an advantage that the section in which the radius of curvature is constant can be specified more accurately. However, since it is necessary to calculate a ratio based on the distance between the two points and the heading difference, the processing load of the arithmetic device 100 However, there is a problem that it takes time to identify a section having a large curvature radius. Therefore, in the second modification, a method is disclosed in which such processing load can be reduced and a section in which the radius of curvature is constant can be specified in a shorter time.

<Configuration>
In the second modification, the CPU 105 functioning as the specifying unit generates a graph as illustrated in FIG. 4 using the acquired combination information. The CPU 105 is analyzed to determine whether there is a section that can be linearly approximated. The analysis can be determined by, for example, a general graph shape analysis technique. On the graph, the section that can be linearly approximated is synonymous with the section in which the ratio of the travel distance and the heading difference is constant, whereby the CPU 105 can specify the section in which the curvature radius is constant. . Then, the CPU 105 calculates the radius of curvature for the section specified by the method. By doing this, the ratio between each two points is calculated, and the section where the radius of curvature is constant without taking the complicated method of specifying the section where the ratio is constant compared to the ratio of the preceding and following sections, respectively. Can be specified.

<Operation>
Hereinafter, operation | movement of the arithmetic unit 100 in this modification 2 is demonstrated using the flowchart shown in FIG. FIG. 6 is a flowchart showing the operation of the arithmetic device 100 according to the second modification.

  As illustrated in FIG. 6, the acquisition unit 101 of the arithmetic device 100 receives GPS time, position information indicating the position of the vehicle, and a heading value (direction information) indicating the direction of the vehicle from the measurement vehicle that outputs the travel information. Are acquired as combination information (step S601). The acquisition unit 101 transmits the acquired combination information to the CPU 105.

  For each piece of acquired combination information, the CPU 105 plots points on a graph with the cumulative heading difference on the vertical axis and the cumulative travel distance on the horizontal axis (step S602). Thereby, for example, a graph as shown in FIG. 4 is obtained.

  The CPU 105 determines whether there is a section that can be linearly approximated by image analysis or the like in the curve of the graph obtained after plotting each combination information (step S603). If there is no section that can be linearly approximated (NO in step S603), the process ends. If there is a section that can be linearly approximated (YES in step S603), the CPU 105 has a constant radius of curvature in the section that can be linearly approximated. Is identified as a section (step S604).

  Then, the CPU 105 calculates the curvature radius based on the ratio between the traveling distance and the heading difference in the section where the specified curvature radius is constant (step S605).

  As shown in the second modification, the arithmetic device 100 first identifies a section where the radius of curvature is roughly constant on the graph from the obtained combination information, and then compares the distance between the travel distance and the heading difference. And the radius of curvature can be calculated. That is, according to this configuration, it is possible to specify a section in which the curvature radius is constant without calculating all the ratios between the combination information, and the processing load on the arithmetic device 100 can be reduced.

<Summary>
As shown in the above embodiment, the arithmetic device 100 easily identifies a section where the radius of curvature is constant by using a section where the ratio of the travel distance of the vehicle and the amount of change in direction information is constant. And the radius of curvature can be calculated. Therefore, the curvature radius of the actual road can be specified by driving the vehicle on the actual road and calculating the curvature radius in each part of the travel locus.

<Supplement>
It goes without saying that the arithmetic device according to the above embodiment is not limited to the above embodiment, and may be realized by other methods. Hereinafter, various modifications will be described.

  (1) In the above embodiment, the arithmetic device 100 may have a function as a normal navigation system and a map creation function for creating a map.

  (2) In the above embodiment, as a method of calculating the radius of curvature in the arithmetic device, the processor of the arithmetic device calculates by executing an arithmetic program or the like. It may be realized by a logic circuit (hardware) or a dedicated circuit formed on a (Integrated Circuit) chip, LSI (Large Scale Integration)) or the like. These circuits may be realized by one or a plurality of integrated circuits, and the functions of the plurality of functional units described in the above embodiments may be realized by a single integrated circuit. An LSI may be called a VLSI, a super LSI, an ultra LSI, or the like depending on the degree of integration. That is, as illustrated in FIG. 7, the arithmetic device 100 may include an acquisition circuit 101a, a reception circuit 102a, an output circuit 103a, a storage circuit 104a, and a control circuit 105a, and the acquisition unit 101 and the reception unit 102, respectively. , Output unit 103, storage unit 104, and CPU 105.

  The arithmetic program may be recorded on a processor-readable recording medium, and the recording medium may be a “non-temporary tangible medium” such as a tape, a disk, a card, a semiconductor memory, a programmable logic circuit. Etc. can be used. The arithmetic program may be supplied to the processor via an arbitrary transmission medium (such as a communication network or a broadcast wave) that can transmit the arithmetic program. The present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the arithmetic program is embodied by electronic transmission.

  The arithmetic program is implemented using, for example, a script language such as ActionScript or JavaScript (registered trademark), an object-oriented programming language such as Objective-C, Java (registered trademark), or C ++, or a markup language such as HTML5. it can.

  (3) Various examples shown in the above embodiment and various examples shown in <Supplement> may be appropriately combined. Also, the operations shown in the flowcharts may be executed in parallel or in parallel if there is no contradiction as a result.

100 arithmetic device 101 acquisition unit 102 reception unit 103 output unit 104 storage unit 105 CPU (ratio calculation unit, identification unit, curvature radius calculation unit, direction information calculation unit)

Claims (16)

An acquisition unit for acquiring a plurality of combination information indicating combinations of vehicle position information and direction information indicating the direction of the vehicle at the position indicated by the position information;
Based on the combination information, a specifying unit that specifies a section in which a ratio between a travel distance of the vehicle and a change amount of the direction information of the vehicle is constant;
A computing device comprising: a radius of curvature calculation unit for calculating a radius of curvature, with the zone specified by the specifying unit as having the constant ratio as a zone having a constant radius of curvature. A ratio for calculating the ratio between the distance between the position information indicated by the two pieces of combination information and the change amount of the direction information in the two pieces of combination information using the two pieces of combination information adjacent to each other. A calculation unit;
The computing device according to claim 1, wherein the specifying unit specifies a section in which the ratio calculated by the ratio calculating unit is constant. The acquisition unit acquires the own vehicle position information acquired by the position information acquisition system mounted on the vehicle transmitted from the vehicle as the position information, and is mounted on the vehicle transmitted from the vehicle. The calculation device according to claim 1, wherein the vehicle direction information acquired by a sensor is acquired as the direction information. The acquisition unit acquires the point plotted by the user with respect to the map as the position information,
The arithmetic device according to claim 1, further comprising: a direction information calculation unit that calculates the direction information at each of the plotted points based on a plurality of the plotted points. When the distance is ΔL, the amount of change is ΔH, the radius of curvature is R, and the circumference is Π, the radius of curvature calculator calculates the radius of curvature using the following equation (1). The arithmetic unit according to any one of claims 1 to 4.

An acquisition step of acquiring a plurality of combination information indicating a combination of vehicle position information and direction information indicating the direction of the vehicle at the position indicated by the position information;
Based on the combination information, a specifying step for specifying a section in which a ratio of a travel distance of the vehicle and a change amount of the direction information of the vehicle is constant;
A calculation method including a curvature radius calculation step of calculating the curvature radius, with the section specified as the ratio being constant in the specifying step being a section where the curvature radius is constant. A ratio for calculating the ratio between the distance between the position information indicated by the two pieces of combination information and the change amount of the direction information in the two pieces of combination information using the two pieces of combination information adjacent to each other. A calculation step,
The calculation method according to claim 6, wherein the specifying step specifies a section in which the ratio calculated by the ratio calculating step is constant. The acquisition step acquires the own vehicle position information acquired by the position information acquisition system mounted on the vehicle transmitted from the vehicle as the position information, and is mounted on the vehicle transmitted from the vehicle. The calculation method according to claim 6 or 7, wherein the vehicle direction information acquired by a sensor is acquired as the direction information. The acquisition step acquires the point plotted by the user on the map as the position information,
The calculation method according to claim 6, further comprising a direction information calculation step of calculating the direction information at each of the plotted points based on a plurality of the plotted points. When the distance is ΔL, the amount of change is ΔH, the radius of curvature is R, and the circumference is Π, the radius of curvature calculation step calculates the radius of curvature using the following equation (2). The calculation method according to any one of claims 6 to 9.

On the computer,
An acquisition function for acquiring a plurality of combination information indicating a combination of vehicle position information and direction information indicating the direction of the vehicle at a position indicated by the position information;
Based on the combination information, a specific function for specifying a section in which a ratio between a travel distance of the vehicle and a change amount of the direction information of the vehicle is constant;
An arithmetic program that realizes a curvature radius calculation function for calculating a curvature radius by setting a section in which the specific function specifies that the ratio is constant as a section having a constant curvature radius. A ratio for calculating the ratio between the distance between the position information indicated by the two pieces of combination information and the change amount of the direction information in the two pieces of combination information using the two pieces of combination information adjacent to each other. Further realize the calculation function,
The calculation program according to claim 11, wherein the specifying function specifies a section in which the ratio calculated by the ratio calculation function is constant. The acquisition function acquires the own vehicle position information acquired by the position information acquisition system mounted on the vehicle transmitted from the vehicle as the position information, and is mounted on the vehicle transmitted from the vehicle. The calculation program according to claim 11 or 12, wherein the vehicle direction information acquired by a sensor is acquired as the direction information. The acquisition function acquires a point plotted by a user on a map as the position information,
The calculation program according to claim 11 or 12, further comprising a direction information calculation function for calculating the direction information at each of the plotted points based on a plurality of the plotted points. When the distance is ΔL, the amount of change is ΔH, the radius of curvature is R, and the circumference is Π, the radius of curvature calculation function calculates the radius of curvature using the following equation (3). The calculation program according to any one of claims 9 to 11.

  The recording medium which recorded the program as described in any one of Claims 12-15.

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