WO2020095567A1

WO2020095567A1 - Saddled vehicle

Info

Publication number: WO2020095567A1
Application number: PCT/JP2019/038139
Authority: WO
Inventors: 由幸黒羽; 一幸丸山; 太古賀; 拡前田
Original assignee: 本田技研工業株式会社
Priority date: 2018-11-06
Filing date: 2019-09-27
Publication date: 2020-05-14

Abstract

This invention comprises a first antenna that is in front of a seat part of a two-wheeled vehicle and communicates with an external vehicle that outputs a signal of a prescribed intensity and a second antenna that is behind the seat part. Further, the position of the external vehicle, which serves as a signal source, is estimated from a first reception intensity for a signal received by the first antenna and a second reception intensity for a signal received by the second antenna. At that time, because the signal received by one of the antennas will be attenuated by a driver, this attenuation can be used to specify the range of the signal source, and the range can be specified by also using GPS.

Description

Saddle type vehicle

The present invention relates to a straddle-type vehicle that contributes to smooth traffic by detecting the position of another vehicle in the vicinity, for example.

In recent years, the standard of Intelligent Transport System (ITS) for communication between vehicles or between vehicles and facilities on the road has been put into practical use, and further development of plans is underway. In the ITS, for example, a vehicle periodically transmits a standardized signal, and the vehicle or facility that receives the standardized signal can use the information included in the received signal. Therefore, by including the vehicle position information in the signal, the position of the vehicle that is the sender can be specified.

GNSS (Global Navigation Satellite System) such as GPS (Global Positioning System) is a technology for identifying vehicle position information (see, for example, Patent Document 1). Further, there has been proposed a technique such as dead reckoning that specifies a position using a gyro sensor, an acceleration sensor, or the like when positioning cannot be performed by GPS.

JP, 2005-199382, A

However, GPS positioning has difficulty in accuracy, and even if the GPS positioning result is received from another vehicle, the position is not always accurate. Therefore, when the position has an important meaning, for example, for warning of the presence of a vehicle in the blind position, it is necessary to further improve the positioning accuracy.

The present invention has been made in view of the above conventional example, and provides a straddle-type vehicle that can specify the position of another vehicle with higher accuracy, thereby improving safety and contributing to smooth traffic. The purpose is to do.

In order to achieve the above object, the present invention has the following configurations. That is, according to one aspect of the present invention, a seating portion on which the driver sits,
A first communication unit that is provided in front of the seating portion and that communicates with an external vehicle that outputs a signal of a predetermined strength,
A straddle-type vehicle that is provided behind the seat portion and includes a second communication unit that communicates with the external vehicle,
From the first reception intensity, which is the intensity of the signal that the first communication unit receives from the external vehicle, and the second reception intensity, which is the intensity of the signal that the second communication unit receives from the external vehicle, the external vehicle And a control means for estimating the position of the vehicle.

According to the present invention, a straddle-type vehicle can be provided which can specify the position of another vehicle with higher accuracy, thereby improving safety and contributing to smooth traffic.

Other features and advantages of the present invention will be apparent from the following description with reference to the accompanying drawings. Note that, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals.

The accompanying drawings are included in the specification and constitute a part of the specification, illustrate the embodiments of the present invention, and together with the description, serve to explain the principles of the present invention.
FIG. 1 is a diagram showing an appearance of a two-wheeled vehicle according to an embodiment. FIG. 2 is a diagram showing the configuration of the ITS control unit of the motorcycle of the embodiment. FIG. 3A is a diagram showing an example of the reception intensity of the ITS signal by the motorcycle of the embodiment. FIG. 3B is a diagram showing an example of the attenuation rate of the ITS signal by the motorcycle of the embodiment. FIG. 4A is a diagram showing an example of reception intensity by each antenna of the motorcycle of the embodiment. FIG. 4B is a diagram showing an example of the reception intensity by each antenna of the motorcycle of the embodiment. FIG. 5A is a diagram showing an example of reception intensity by each antenna of the motorcycle of the embodiment. FIG. 5B is a diagram showing an example of reception intensity by each antenna of the motorcycle of the embodiment. FIG. 6 is a flowchart of a processing procedure for identifying the vehicle position of the signal source from the reception intensity of the antenna according to the first embodiment. FIG. 7 is a flowchart of a processing procedure for identifying the vehicle position of the signal source from the reception intensity of the antenna according to the second embodiment.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. The following embodiments do not limit the invention according to the claims, and not all combinations of the features described in the embodiments are essential to the invention. Two or more features of the plurality of features described in the embodiments may be arbitrarily combined. Further, the same or similar configurations are designated by the same reference numerals, and duplicated description will be omitted.
[First embodiment]
● Structure of Saddle-type Vehicle FIG. 1 shows an example of the external appearance of a powered two-wheeled vehicle that is a saddle-type vehicle according to the present embodiment. The invention according to the present embodiment can be applied to a straddle-type vehicle in which the driver's body can have a positional relationship such that the driver's body serves as a shield for antennas arranged in front of and behind the vehicle. Therefore, it is not limited to two wheels and may be three wheels or four wheels, and the power source is not particularly limited.

Fig. 1 shows a state in which passengers are on board. A driver 2 rides on a two-wheeled vehicle so as to straddle a seated portion, and an external facility or vehicle (herein referred to as an external vehicle) is attached to each of a front portion and a rear portion of the vehicle so as to sandwich the driver.

Antennas

11 and 12 are arranged as a first communication unit and a second communication unit for receiving the transmitted ITS signal. The

antennas

11 and 12 can be used not only for signal reception but also for signal transmission. In addition, the names of the first communication unit and the second communication unit may be used as names including not only antennas but also circuits for modulation and signal processing. The ITS signal here refers to a signal standardized (standardized) by the intelligent transportation system (ITS), and is transmitted and received by a vehicle or facility equipped with the ITS system. The ITS signal includes information according to the standard and information extended according to the standard. Here, it is assumed that the ITS signal includes vehicle information including the type of the transmission source (or transmission source) vehicle and position information indicating the position of the transmission source vehicle or facility. However, depending on the GNSS installed in the vehicle, this position information may include an error of about a dozen meters from the implementation position. Furthermore, it is assumed that the transmission power of the ITS signal is substantially constant regardless of the vehicle, and that the frequency band is 5 GHz, which is relatively unaffected by precipitation such as rain and snow.

Fig. 2 shows a block diagram of the ITS system installed in the motorcycle 1. The ITS system includes a control unit 21 for controlling the ITS system,

antennas

11 and 12 for transmitting and receiving signals, various switches, a display unit 216 such as an LED as an interface with a driver, a voice output unit 217 such as a speaker, and the entire earth. It includes a GNSS antenna 213 that receives signals from satellites for the Global Navigation Satellite System (GNSS), such as the Positioning System (GPS). The control unit 21 is further connected to a power source via a power relay, and is also connected to an in-vehicle network (CAN, full (F-) CAN in FIG. 2) 22.

The control unit 21 is connected to the GNSS antenna 213 to perform demodulation of received signals and the like, the GNSS control unit 212 connected to the

antennas

11 and 12 to perform modulation and demodulation of signals in the 5 GHz band, and the like. It includes a human-machine interface (HMI) 215 connected to the unit 216 and the voice output unit 217. Further, it includes a CPU 211 for controlling them, and the CPU 211 has a memory for storing programs and data. In the memory, a C-ITS application 2111, which is a program for performing transmission / reception of signals according to ITS and control based on received signals, the reception intensity of ITS signals by the

antennas

11 and 12, and the position of the signal source of the transmission source ( For example, a position table (position TBL) 2112 in which a distance and a relative direction with respect to the vehicle are associated with each other is stored. Note that the C-ITS shown in FIG. 2 is a collaborative ITS and can also be called an advanced version of ITS.

In the present embodiment, with the configuration shown in FIGS. 1 and 2, an ITS signal transmitted from an external vehicle is received, and the position of the transmission source external vehicle is specified based on the signal. Then, the identified position can be shown to the driver by the display unit 216, for example. Alternatively, since the ITS signal is periodically transmitted from the vehicle, the locus of the vehicle can be specified by plotting the position of the vehicle, the possibility of collision with the two-wheeled vehicle 1 can be determined, and the driver can be warned. Alternatively, it is possible to collate with the map information and output a warning when it is determined that the detected vehicle position is shielded by a structure or the like as viewed from the two-wheeled vehicle 1.

● Attenuation of received signal The transmitted ITS signal is attenuated according to its propagation distance. In this embodiment, the distance of the external vehicle that is the transmission source is estimated based on the signal strengths received by the

antennas

11 and 12 of the motorcycle 1. The principle is shown in FIG. 3A. The circle 31 indicates the distance to the transmission source estimated from the intensity of the signal received by the antenna 11. The circle 32 indicates the distance to the transmission source estimated from the strength of the signal received by the antenna 12. The

intersections

331 and 332 of these two

circles

31 and 32 are the estimated signal source positions. Although it is difficult to specify the direction from only the signal power, it may be estimated as the position of the intersection outside vehicle closer to the position information included in the received ITS signal, for example. However, the above is the case where the damping by the driver 2 is not taken into consideration.

While the driver is on board, the signal is further attenuated by the driver's body. For example, with respect to the antenna 11 on the front side of the vehicle body, if the signal is emitted from before the line of sight 35 (referred to as the line-of-sight range), there is almost no attenuation by the human body, but if it is behind it (called the non-line-of-sight range), there is no attenuation by the human body. is there. Although only the left half is shown in the figure, the right side is also in contrast. As a result, the signal received by the antenna 11 from the signal source in the non-line-of-sight region is greatly attenuated, and the estimated distance based on the signal is large as compared with the case where there is no attenuation by the human body, as shown by the dotted line 36. This is the same for the antenna 12, but the front and rear are reversed from the antenna 11. That is, the signal received by the antenna 12 from the signal source in the non-line-of-sight region ahead of the line-of-sight 34 has large attenuation, and the estimated distance based on the signal is as shown by the dotted line 37 when there is no attenuation by the human body. It will be larger than that. Therefore, when estimating the distance, the estimation is performed so as to correct the attenuation due to the human body. FIG. 3B shows an example of the distribution of the damping rate when the frontal direction of the motorcycle 1 is set to 0 and the clockwise direction of 180 degrees is set to the rearward direction of the motorcycle 1. A curve 301 shows the distribution of the attenuation rate by the driver 2 around the antenna 11. From the line-of-sight line 35, there is no attenuation by the human body in the line-of-sight region, and there is attenuation by the human body in the non-line-of-sight region. A curve 302 is an example showing the distribution of the attenuation rate by the driver 2 centering on the antenna 12, and like the antenna 11, there is no attenuation by the human body in the line-of-sight region.

It should be noted here that the difference in received signal power between the antenna 11 and the antenna 12 becomes larger due to the attenuation of the signal by the human body than in the case where there is no attenuation by the human body, and the signal source is utilized by utilizing the difference. That is, it is easy to determine whether it is located ahead of the antenna 11 (that is, in front of it) but ahead of the antenna 12 (that is, behind it). In the present embodiment, the attenuation due to the human body is corrected, and the position of the signal source is estimated using the attenuation.

● Example of received signal Fig. 4A, Fig. 4B, Fig. 5A, and Fig. 5B show examples of received signal strength. FIG. 4A shows an example in which the wheeled vehicle 1 on which the driver 2 is placed receives the ITS signal from the vehicle in front. In this case, the field intensity received by each antenna is as shown in the graph on the right side of FIG. 4A. In this graph, the vertical axis represents the radio field intensity and the horizontal axis represents the distance from the signal transmission source. Of course, this is a schematic diagram, and the actual intensity distribution does not always look like this. In the case of FIG. 4A, the antenna 12 is farther from the signal source than the antenna 11, and the driver 2 is located between the signal source and the antenna 12. Therefore, the reception intensity of the antenna 12 is smaller than that of the antenna 11, and the degree of attenuation is much greater than the attenuation due to the distance alone (shown by the dotted line). In FIG. 4A, the difference from the attenuation due to only this distance is indicated by the symbol α. As described above, when the signal source is in the non-line-of-sight area as viewed from one antenna, the difference in the received signal strength between the antennas exceeds the difference in the signal strength due to the difference in distance alone and becomes large.

FIG. 4B shows an example of a case where an ITS signal transmitted by an external vehicle is received from the rear of the motorcycle 1. 4A is the same as that of FIG. 4A, but since the position of the transmission source is the front side on the rear side, the received radio wave intensity is strong on the antenna 12 side and on the antenna 11 side accompanied by human body attenuation as shown in the graph on the right side of FIG. 4B. Extremely weak beyond the extent of attenuation due to distance. Although there is a difference from FIG. 4A in that the position of the radio wave source is behind the vehicle 1, the degree to which the radio wave is blocked and attenuated by the driver's body is almost the same. That is, also in FIG. 4B, the amount of attenuation by the driver's body is α.

FIG. 5A shows an example of signal strength when an ITS signal from an external vehicle is received from the diagonally right front of the motorcycle 1. Also in this case, similarly to FIG. 4A, the signal strength of the antenna 12 becomes smaller than that of the antenna 11 beyond the degree of attenuation due to distance. However, as compared with the case where a signal is received from the front as shown in FIG. 4A, the degree of attenuation by the human body is small. In FIG. 5A, the attenuation due to the driver's body is diagonally ahead of the radio wave source, and the attenuation amount β is smaller than the attenuation amount α in FIGS. 4A and 4B. That is, α> β. FIG. 5B also shows an example of signal strength when an ITS signal from an external vehicle is received from the diagonally right front of the two-wheeled vehicle 1. Also in this case, similarly to FIG. 5A, the signal strength of the antenna 12 becomes smaller than that of the antenna 11 beyond the degree of attenuation due to distance. However, compared to the case of FIG. 5A, the external vehicle is closer to the front of the motorcycle 1. Therefore, the degree of attenuation by the human body is larger than that in FIG. 5A, and the degree of attenuation is smaller than that in the case of FIG. 4A. That is, in FIG. 5B, the attenuation by the driver's body is an attenuation amount γ that is smaller than the attenuation amount α in FIGS. 4A and 4B and larger than the attenuation amount β in FIG. 5A. That is, α> γ> β. 5A and 5B, even if there is a radio wave source obliquely behind, the antennas that receive attenuated radio waves are in the same reception state as in FIGS. 5A and 5B, although the antennas differ depending on the direction of the vehicle body. In this way, the signal (radio waves) is attenuated by the driver according to the positional relationship between the radio wave source, the antenna, and the driver, and the difference in received power between the two antennas is only the difference that depends only on the distance. Instead, the difference will include attenuation depending on the direction of the radio wave source.

In this way, the position of the signal source, that is, the external vehicle is specified based on the difference in the distance from each antenna to the signal source, using the two antennas and considering the attenuation by the driver. In the present embodiment, the intensity of the radio wave received by each antenna is set as a set of radio field intensities, and the radio wave intensity of each set is prepared in advance in a memory by preparing a position table 2112 in which the position of the signal source is associated with the position of the signal source. A set of radio field intensities that match the received radio field intensity is searched from the position table 2112, and the position associated therewith is specified as the position of the external vehicle. Here, the position table 2112 is created by the following method, for example. That is, in a state where the driver is riding on the two-wheeled vehicle, the ITS signal is arranged, for example, at any one of grid points of a grid with a predetermined interval in the vertical and horizontal directions centering on the two-wheeled vehicle 1, and the ITS signal is transmitted at that position. The motorcycle 1 measures the radio field intensity of each antenna at that time. Then, the set of the radio field intensities is registered in the position table 2112 in association with the position of the signal source which is known in advance. The position table 2112 is completed by performing this measurement and registration by locating the signal source at each grid point within a certain range centering on the motorcycle. Here, the position may be represented by a distance from the two-wheeled vehicle 1 and a relative direction based on the orientation of the two-wheeled vehicle 1, for example. Further, the position table created in this way is considered to be bilaterally symmetric with respect to, for example, the traveling direction of the two-wheeled vehicle 1. Therefore, only one of the left and right sides may be provided. In the present embodiment, the position table 2112 is assumed to be provided for the half area created in this way. FIG. 6 shows details of the procedure for specifying the position of the external vehicle using the position table 2112.

● ITS signal reception process FIG. 6 shows a procedure when the ITS system of the motorcycle 1 receives an ITS signal from an external vehicle. This procedure is realized by executing the C-ITS application by the CPU 211. The procedure of FIG. 6 is started when the ITS signal from the external vehicle is received.

First, the strength of the signal (radio wave) received by each of the

antennas

11 and 12 is digitized, and the position table 2112 is searched by the set of the values (S601). If a match is registered, the position associated with that set of values is specified. If there is no set of matching values, for example, the antenna with the higher received signal strength is specified, and for the specified antenna, the position table 2112 having a signal strength within a predetermined difference from the strength of the received signal by the antenna. To identify the entry. With that entry as a candidate, the entry having the value closest to the received signal strength is determined for the antenna having the lower received signal strength. The position included in the determined entry is specified as the position of the signal source. Since the position of the grid point registered in advance is specified in this way, the position deviated from the grid point may be specified by supplementing the position according to the observed signal strength.

Next, position information is acquired from the received ITS signal (S603). The position specified in S601 indicates one of two positions that are symmetrical with respect to the line connecting the two antennas of the two-wheeled vehicle 1 (in this example, the straight traveling direction). Yes (S605). For that purpose, the current position of the two-wheeled vehicle 1 is specified based on the GNSS signal received from the satellite, and the direction of the two-wheeled vehicle (that is, the direction of the line connecting the two antennas) is specified based on the direction information obtained from the electronic compass (not shown). Then, based on the current position and direction of the motorcycle 1, it is specified whether the position indicated by the position information of the ITS is on the left or right side of the motorcycle 1. Then, the position of the external vehicle is specified by converting the position specified in S601 depending on whether it is on the left or right (S605). Here, the direction of the external vehicle is converted, and the distance may not be converted. Regarding the direction, for example, the right side is represented by a positive sign and the left side is represented by a negative sign with reference to the front direction, and the position table 2112 includes entries for only the right side. In this case, if the position of the external vehicle is determined to be the right side by the position information of the GNSS, the position specified in S601 becomes the position of the external vehicle, and if determined to be the left side, the sign of the value indicating the direction is inverted. In this way, the position of the external vehicle can be specified.

Finally, actions such as showing the position of the specified external vehicle to the driver or outputting a warning are performed (S607). Here, the type of warning may be changed based on the information indicating the type of vehicle obtained from the ITS signal, or the type of warning may be changed according to the distance to the external vehicle.

With the configuration and procedure described above, the position of the external vehicle can be specified with high accuracy. In particular, the characteristic of the attenuation of the radio signal by the driver peculiar to the two-wheeled vehicle increases the difference in the received signal strength between the plurality of antennas, so that it is possible to avoid position determination with many errors using a subtle strength difference.

[Modification 1 of the first embodiment]
In the above-described first embodiment, the characteristics of attenuation of the radio signal by a person may differ depending on the physique, clothes, etc. of the driver. Therefore, the characteristics of the attenuation are estimated each time the driver or his / her clothes change, and the signal values of the positions of the entries of the position table 2112 belonging to the non-line-of-sight region are corrected accordingly. The correction may be performed by rewriting the position table 2112, or a correction table may be prepared separately. The characteristics are estimated as follows, for example. That is, the signal values when one antenna is set to the transmitting side and the other antenna is set to the receiving side are measured at the time of creating the position table 2112 in the riding state with the driver and the unloaded state without the driver, and the respective values are measured. Is stored in the memory together with the position table 2112. This is a reference value, and the ratio of the signal strength in the riding state to the signal strength in the non-riding state is set as the reference damping characteristic. This value may also be stored.

Then, at the time of correction, the signal value when one of the antennas is the transmitting side and the other is the receiving side is measured in the same manner as when the position table 2112 was created with the driver on board. Then, the ratio of signal intensities measured with the stored signal intensities in the non-riding state as a reference, that is, the current attenuation characteristic is obtained. The ratio of this current damping characteristic to the reference damping characteristic is the correction factor. The position table 2112 is corrected by multiplying the signal strength, which is included in the position table 2112 and corresponds to all the positions in the non-line-of-sight region, for each antenna by this correction factor. It is also possible to separately store the reference position table and create the corrected position table from the reference position table each time the correction is performed.

By correcting the position table in this way, it is possible to correct variations in the received signal value due to the driver's clothes, physique, etc., and it is possible to more accurately specify the position of the external vehicle.

[Modification 2 of the first embodiment]
In the first embodiment, the size of the position table 2112 is halved by using the symmetry of the relationship between the received signal and the position of the signal source, but in the present embodiment it can be further halved. That is, it can be determined whether the signal source is before or after the two-wheeled vehicle depending on which of the antenna 11 and the antenna 12 has the higher received signal strength. Therefore, if the antenna 11 and the antenna 12 are the same antenna, it can be considered that the relationship between the received signal and the position of the signal source is symmetrical in the front-back direction. Moreover, this symmetry can be determined only from the received signal strength, even without the position information of the external vehicle. That is, in this case, of the four quadrants divided by the axis of the straight direction of the two-wheeled vehicle and the axis orthogonal to the axis and passing through the middle of the two antennas, the two quadrants of the two antennas are The position table 2112 may have the relationship between the received signal strength and the position of the signal source. Then, in step S605 of FIG. 6, whether the signal source is on the left or right side is determined based on the position information, and whether the signal source is front or back is determined based on the received signal strengths of the two antennas. Then, the direction is determined based on the determination. If the front of the two-wheeled vehicle 1 is 0 degrees, and if it is determined to be rearward, the angle indicating the direction obtained from the position table 2112 is subtracted from 180 degrees. Further, if it is determined to be left, the sign is inverted. In this way, the size of the position table 2112 can be further reduced. Even if the position information is not included in the ITS signal, the amount of the position table can be reduced by half as in the present embodiment.

[Second embodiment]
Next, a second embodiment will be described with reference to FIG. In the present embodiment, it is particularly easy to determine whether the signal source is before or after the two-wheeled vehicle due to the attenuation of the radio wave by the body of the driver. Therefore, in the present embodiment, first, it is determined whether the signal source, that is, the external vehicle is in the front or rear, and then the position of the external vehicle is specified.

When receiving the ITS signal, first, the received signal strengths of the antenna 11 and the antenna 12 are compared (S701). Then, one of the received signals having the lower signal strength is corrected (S703 to S707). For the correction, for example, the characteristic of the attenuation factor for each antenna as shown in FIG. 3B is digitized and held, and the compensation is performed so as to compensate for the attenuated amount. Since the

circles

31 and 32 indicating the distance from each antenna as shown in FIG. 3A, for example, can be specified by the corrected signal strength, the

intersections

331 and 332 thereof are specified. From among them, for example, as shown in the first embodiment, the position specified by the GNSS signal is referenced and determined (S709). Finally, a display or warning is output to the driver regarding the position (S711).

As described above, according to the present embodiment, the position of the external vehicle can be specified with high accuracy by utilizing the characteristic of the attenuation of the received signal by the occupant, which is unique to the two-wheeled vehicle.

Summary of Embodiments The following is a summary of the present embodiment described above.
(1) According to the first aspect of the present invention,
A seat on which the driver sits,
A first communication unit that is provided in front of the seating portion and that communicates with an external vehicle that outputs a signal of a predetermined strength,
A straddle-type vehicle that is provided behind the seat portion and includes a second communication unit that communicates with the external vehicle,
From the first reception intensity, which is the intensity of the signal that the first communication unit receives from the external vehicle, and the second reception intensity, which is the intensity of the signal that the second communication unit receives from the external vehicle, the external vehicle And a control means for estimating the position of the vehicle.

As a result, it is possible to improve the accuracy of identifying the position of the external vehicle by utilizing the attenuation of radio waves by the driver.
(2) According to a second invention related to the present embodiment, the straddle-type vehicle according to (1),
When the first reception intensity is greater than the second reception intensity, the control means determines that the external vehicle is present in front of the saddle-type vehicle, and determines the first reception intensity from the first reception intensity. (2) A straddle-type vehicle is provided, which is characterized in that it is determined that the external vehicle is behind the saddle-type vehicle when the reception strength is higher.

As a result, it is possible to improve the accuracy of identifying the position of the external vehicle by utilizing the attenuation of radio waves by the driver.
(3) According to a third aspect of the present invention, a straddle-type vehicle according to (2),
A position table in which a pair of the first reception intensity and the second reception intensity is associated with a position of a signal source is provided for each of a front range and a rear range of the saddle type vehicle,
The control means determines the position of the signal source associated with the set of the first reception intensity received by the first communication means and the second reception intensity received by the second communication means, from the external vehicle. A straddle-type vehicle characterized by being specified as a position is provided.

As a result, it is possible to improve the accuracy of identifying the position of the external vehicle by utilizing the attenuation of radio waves by the driver.
(4) According to a fourth aspect of the present invention, in the straddle-type vehicle according to (1),
A position table that associates a pair of the first reception intensity and the second reception intensity with the position of the signal source;
The control means determines the position of the signal source associated with the set of the first reception intensity received by the first communication means and the second reception intensity received by the second communication means, from the external vehicle. A straddle-type vehicle characterized by being specified as a position is provided.

Thereby, the accuracy can be further improved.
(5) According to a fourth aspect of the present invention, the straddle-type vehicle according to (3) or (4),
The signal received from the other vehicle includes position information of the external vehicle positioned by the Global Navigation Satellite System,
When there are a plurality of positions specified by the control means based on the first reception strength and the second reception strength, a position close to the position indicated by the position information is specified as the position of the external vehicle. A straddle-type vehicle is provided.

As a result, it is possible to specify from a plurality of candidate positions, accuracy can be improved, and required storage capacity can be reduced.
(6) According to a fourth aspect of the present invention, in the straddle-type vehicle according to any one of (3) to (5),
The position table has the first reception intensity and the second reception intensity measured in advance according to the position of the signal source in a state in which an occupant is on the saddle riding type vehicle. Vehicles are provided.

By doing so, it is possible to specify from multiple candidate positions, and it is possible to improve accuracy and reduce the required storage capacity.

The present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, in order to make the scope of the present invention public, the following claims are attached.

The present application claims priority based on Japanese Patent Application No. 2018-209156 filed on November 6, 2018, and the entire content of the description is incorporated herein.

Claims

A seat on which the driver sits,
A first communication unit that is provided in front of the seating portion and that communicates with an external vehicle that outputs a signal of a predetermined strength,
A straddle-type vehicle that is provided behind the seat portion and includes a second communication unit that communicates with the external vehicle,
From the first reception intensity, which is the intensity of the signal that the first communication unit receives from the external vehicle, and the second reception intensity, which is the intensity of the signal that the second communication unit receives from the external vehicle, the external vehicle And a control means for estimating the position of the vehicle.
The straddle-type vehicle according to claim 1,
When the first reception intensity is greater than the second reception intensity, the control means determines that the external vehicle is present in front of the saddle-type vehicle, and determines the first reception intensity from the first reception intensity. (2) A straddle-type vehicle, characterized in that when the reception strength is higher, it is determined that the external vehicle is behind the saddle-type vehicle.
The straddle-type vehicle according to claim 2,
A position table in which a pair of the first reception intensity and the second reception intensity is associated with a position of a signal source is provided for each of a front range and a rear range of the saddle type vehicle,
The control means determines the position of the signal source associated with the set of the first reception intensity received by the first communication means and the second reception intensity received by the second communication means, from the external vehicle. A straddle-type vehicle characterized by being specified as a position.
The straddle-type vehicle according to claim 1,
A position table that associates a pair of the first reception intensity and the second reception intensity with the position of the signal source;
The control means determines the position of the signal source associated with the set of the first reception intensity received by the first communication means and the second reception intensity received by the second communication means, from the external vehicle. A straddle-type vehicle characterized by being specified as a position.
The straddle-type vehicle according to claim 3 or 4, wherein
The signal received from the other vehicle includes position information of the external vehicle positioned by the Global Navigation Satellite System,
When there are a plurality of positions specified by the control means based on the first reception strength and the second reception strength, a position close to the position indicated by the position information is specified as the position of the external vehicle. A straddle-type vehicle characterized by.
The straddle-type vehicle according to any one of claims 3 to 5,
The position table has the first reception intensity and the second reception intensity measured in advance according to the position of the signal source in a state in which an occupant is on the saddle riding type vehicle. vehicle.