JP4665819B2 - Portable terminal, approach detection device, and approach detection system - Google Patents

Description

  The present invention relates to a portable terminal, an approach detection device, and an approach detection system using them.

2. Description of the Related Art Conventionally, a technique for detecting a person around a vehicle by receiving a radio wave emitted by a portable terminal carried by a person such as a pedestrian is known (for example, see Patent Document 1). In the technique described in Patent Literature 1, the radio wave of a portable terminal carried by a person is received by an in-vehicle device mounted on the vehicle, and the distance between the vehicle and the person carrying the portable terminal is obtained from the reception level.
JP 2005-202874 A

  By the way, since the human body is a dielectric, the characteristics of the antenna of the mobile terminal change under the influence of the human body. For example, the gain of a dipole antenna decreases as it approaches the body. On the other hand, the gain of the loop antenna improves as it approaches the body. Therefore, the transmission / reception level changes depending on whether the portable terminal is held in close contact with the body or held away from the body. As a result, in the above-described technology, there is a possibility that the required error in the distance between the in-vehicle device and the portable terminal becomes large.

  The present invention has been made to solve the above-described problems, and is capable of estimating the distance between a person and a moving body with higher accuracy, an approach detection device, and an approach detection system using them. The purpose is to provide.

A portable terminal according to the present invention detects a reception level of a radio wave received by a receiving unit in a portable terminal including a receiving unit and a transmitting unit that perform wireless communication with an approach detection device mounted on a moving body. A reception level detecting means; and a correction value calculating means for obtaining a level correction value for correcting the reception level based on a peak value and a change gradient of the reception level when the mobile body passes. A correction value is transmitted.

As described above, since the human body is a dielectric, when the mobile terminal is brought close to the body, the antenna gain is reduced or improved (hereinafter sometimes referred to as “decrease / improvement”) and the reception level is reduced. /improves. Therefore, when the mobile body passes near the person who holds the mobile terminal close to the body, the reception level is compared with the case where the mobile body passes the vicinity of the person holding the mobile terminal away from the body. The peak value decreases / improves. On the other hand, the reception level also changes when the distance between the mobile object and the mobile terminal changes. In this case and when the antenna gain decreases / improves, the change gradient of the reception level when the mobile object passes Is different. According to the mobile terminal of the present invention, using this characteristic, the amount of reduction or improvement in the reception level caused by bringing the mobile terminal closer to the body is corrected based on the peak value and change gradient of the reception level. A level correction value for this is obtained.

  On the other hand, when the portable terminal is brought close to a human body, the antenna gain is reduced / improved and the transmission level is also lowered / improved. That is, the reception level at the proximity detection device that receives radio waves from the mobile terminal is also reduced / improved. Here, according to the portable terminal according to the present invention, since the obtained level correction value is transmitted by the transmission means, the portable terminal is brought closer to the body on the approach detection device side that receives the radio wave from the portable terminal. It is possible to correct the reduction / improvement of the reception level due to the above.

  The correction value calculating means obtains a level correction value according to the change gradient of the reception level when the peak value of the reception level is out of the predetermined range and the change gradient of the reception level is larger than the predetermined gradient. preferable.

  As described above, the reception level is reduced / improved when the moving body passes in the vicinity of the person holding the portable terminal in close contact with the body. However, when the mobile device is held in close contact with the body (ie, when the gain of the antenna is reduced / improved), the same change as when the mobile device is held away from the body The reception level is lowered / improved as a whole while maintaining the shape (change gradient). On the other hand, when the distance between the person carrying the mobile terminal and the moving body is far away, the gradient of the reception level becomes gentle because the mobile terminal deviates quickly from the directional front of the antenna.

  According to the mobile terminal of the present invention, by using this characteristic, the reception level is lowered when the peak value of the reception level is out of the predetermined range and the change gradient of the reception level is larger than the predetermined gradient. / Level correction to determine that the improvement is due to the decrease / improvement of the antenna gain and to correct the reduction / improvement of the reception level caused by bringing the mobile terminal closer to the body from the gradient of the reception level The value can be determined.

  The correction value calculation means calculates the level correction value according to the change gradient of the reception level when the peak value of the reception level is smaller than the lower threshold and the change gradient of the reception level is larger than a predetermined gradient. It is preferable to obtain.

  For example, when using an antenna whose gain is reduced by approaching the body, such as a dipole antenna, it is received when the mobile object passes near the person holding the mobile terminal in close contact with the body. The level drops. However, when the mobile device is held in close contact with the body (that is, when the gain of the antenna is reduced), the same change shape (when the mobile device is held away from the body) ( The reception level decreases as a whole while maintaining the change gradient. On the other hand, when the distance between the person carrying the mobile terminal and the moving body is far away, the gradient of the reception level becomes gentle because the mobile terminal deviates quickly from the directional front of the antenna.

  According to the mobile terminal of the present invention, by using this characteristic, when the peak value of the reception level is smaller than the lower limit threshold and the change gradient of the reception level is larger than the predetermined gradient, the reception level Is determined to be due to a decrease in antenna gain, and a level correction value for correcting the amount of decrease in reception level caused by bringing the mobile terminal closer to the body from the gradient of the reception level can be obtained. it can.

  The correction value calculating means corrects the level according to the change gradient of the reception level when the peak value of the reception level is larger than the upper threshold and the change gradient of the reception level is larger than a predetermined gradient. It is preferable to determine the value.

  For example, when using an antenna that increases gain by being close to the body, such as a loop antenna, it is received when the mobile object passes near the person holding the mobile terminal in close contact with the body. Level is improved. However, when the mobile device is held in close contact with the body (that is, when the gain of the antenna is improved), the same change shape (when the mobile device is held away from the body) The reception level improves as a whole while maintaining the change gradient.

  According to the mobile terminal of the present invention, by using this characteristic, when the peak value of the reception level is larger than the upper limit threshold and the change gradient of the reception level is larger than a predetermined gradient, the reception level It is determined that the improvement is due to the improvement of the antenna gain, and a level correction value for correcting the improvement amount of the reception level caused by bringing the mobile terminal closer to the body from the gradient of the reception level can be obtained. it can.

  Here, it is preferable that the correction value calculation means calculates the level correction value by obtaining level correction values for a plurality of moving bodies and averaging the plurality of level correction values. In this way, it is possible to further improve the accuracy of the level correction value.

  An approach detection device according to the present invention is mounted on a mobile body, performs wireless communication with any of the mobile terminals described above, and detects an approach state with the mobile terminal. Terminal information receiving means for receiving the received radio wave and obtaining a level correction value, terminal reception level detecting means for detecting the reception level of the radio wave from the portable terminal received by the terminal information receiving means, and terminal reception level detecting means Correction means for correcting the reception level detected based on the level correction value, and distance calculation means for obtaining the distance from the portable terminal based on the corrected reception level.

  As described above, when the portable terminal is brought close to a human body, the antenna gain is reduced and the transmission level is lowered, so that the reception level at the proximity detection device is also lowered. However, according to the proximity detection apparatus of the present invention, the reception level of the radio wave emitted from the mobile terminal is corrected using the level correction value, and the distance from the mobile terminal is obtained based on the corrected reception level. In this way, since the amount of decrease in the reception level caused by bringing the mobile terminal closer to the body is corrected, the distance between the person holding the mobile terminal and the mobile body equipped with the proximity detection device is estimated more accurately. It becomes possible to do.

  An approach detection system according to the present invention includes any one of the portable terminals described above and the approach detection device.

  According to the proximity detection system of the present invention, as described above, the level correction value for correcting the reduction / improvement amount of the reception level caused by bringing the mobile terminal closer to the body is obtained by the mobile terminal. And transmitted to the approach detection device mounted on the moving body. On the other hand, in the proximity detection device, the reduction / improvement amount of the reception level caused by bringing the mobile terminal closer to the body is corrected using the level correction value, and the distance from the mobile terminal is determined based on the corrected reception level. Desired. As a result, the distance between the person carrying the portable terminal and the moving body on which the proximity detection device is mounted can be determined more accurately.

  According to the present invention, the amount of change in the antenna gain caused by bringing the mobile terminal closer to the body is corrected, so that the distance between the person and the moving body can be estimated more accurately.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same reference numerals are given to the same components in the drawings as much as possible, and duplicate descriptions are omitted.

  First, the configurations of the proximity detection system 1 according to the first embodiment, the portable terminal 2 and the proximity detection device 3 constituting the proximity detection system 1 will be described using FIGS. FIG. 1 is a diagram illustrating a configuration of the approach detection system 1. FIG. 2 is a block diagram of the portable terminal 2 constituting the approach detection system 1. FIG. 3 is a block diagram of the approach detection device 3 constituting the approach detection system 1.

  The approach detection system 1 includes a mobile terminal 2 possessed by pedestrians Ha, Hb, and Hc (hereinafter, sometimes collectively referred to as pedestrians H) in FIG. 1 and vehicles V1 and V2 (hereinafter referred to as mobile bodies). , And may be generally referred to as a vehicle V). In this specification, “pedestrian” includes not only those who are walking, but also those who travel on the sidewalk by riding bicycles or wheelchairs, for example.

  The mobile terminal 2 according to the present embodiment includes a dipole antenna whose gain is reduced by approaching a human body, and is approached from the approach detection device 3 mounted on the approaching vehicle V1. The information is received and notified to the owner of the portable terminal 2. Moreover, the portable terminal 2 calculates | requires a level correction value based on the reception level of the electromagnetic wave from the approach detection apparatus 3 when the vehicle V1 passes the vicinity. Then, the obtained level correction value is transmitted to the approach detection device 3 mounted on the next approaching vehicle V2.

  On the other hand, the approach detection device 3 mounted on the vehicle V2 receives the radio wave emitted from the mobile terminal 2 and detects the level correction value. Then, the reception level of the radio wave from the portable terminal 2 is corrected by the level correction value, and the directions of the pedestrians Ha, Hb, Hc and the pedestrians Ha, Hb, Hc carrying the portable terminal 2 based on the corrected reception level. Distance, that is, a pedestrian position is estimated. And the approach detection apparatus 3 produces | generates approach information based on the estimated pedestrian position and the driving | running | working state of the own vehicle, while alert | reporting with respect to the driver | operator of the vehicle V2, and produced | generated approach information is a portable terminal. 2 is transmitted.

  As shown in FIG. 2, the mobile terminal 2 has an antenna 20 for transmitting and receiving radio waves of a predetermined frequency. In the present embodiment, as the antenna 20, an antenna whose gain is reduced by approaching a human body, for example, a dipole antenna is used. The radio wave received from the approach detection device 3 received by the antenna 20 is demodulated by the reception unit 21 and then output to the reception level, ID, and vehicle speed detection unit 22. The reception level, ID, and vehicle speed detection unit 22 detects the reception level of the received radio wave and also detects ID (Identification) information and vehicle speed information from the received data. That is, the receiving unit 21 functions as a receiving unit described in the claims, and the reception level, ID, and vehicle speed detecting unit 22 functions as a receiving level detecting unit.

  The information providing unit 23 is connected to the reception level, ID, and vehicle speed detection unit 22, and when the detected ID matches its own ID (terminal ID), walking with the portable terminal 2 from the information providing unit 23 The person is informed that the vehicle V is approaching. The information providing unit 23 presents to the pedestrian that the vehicle V is approaching, for example, by voice information, visual display information, and vibration.

  The reception level / ID / vehicle speed detection unit 22 is connected to a level correction value calculation unit 24 and an ID / level correction value transmission unit 25. The detected reception level, vehicle ID, and vehicle speed information are level-corrected. In addition to being output to the value calculation unit 24, the reception level and the vehicle ID are output to the ID and level correction value transmission unit 25.

  In the level correction value calculation unit 24, the reception level and the vehicle speed when the vehicle V1 passes in the vicinity of the pedestrian carrying the mobile terminal 2 are recorded, and the relationship between the movement distance of the vehicle V1 and the reception level obtained from the vehicle speed is recorded. To be acquired. Then, based on the peak value and the change shape of the reception level, a level correction value for correcting the reduction amount of the reception level caused by bringing the mobile terminal 2 close to the pedestrian's body is obtained. That is, the level correction value calculation unit 24 functions as correction value calculation means described in the claims.

  Here, with reference to FIG. 4, a method for determining whether or not the decrease in the reception level is caused by holding the portable terminal 2 close to the body will be described. Here, as shown in FIG. 1, the vehicle V1 approaches from the right direction of the pedestrians Ha and Hb carrying the portable terminal 2 (in front of the pedestrian Hc diagonally to the right), and the front of the pedestrians Ha, Hb and Hc. The case of passing through will be described as an example. The vehicle V1 is assumed to travel along the traveling direction indicated by the alternate long and short dash line in FIG. Since the pedestrians Ha and Hb are located near the traveling direction of the vehicle V1, the vehicle V1 passes close to the pedestrians Ha and Hb. On the other hand, the pedestrian Hc is located at a location farther away from the traveling direction of the vehicle V1 than the pedestrians Ha and Hb. Therefore, the vehicle V1 passes through a place away from the pedestrian Hc.

  The pedestrian Ha and the pedestrian Hc carry the portable terminal 2 away from the body, for example, attached to a bag. On the other hand, the pedestrian Hb is in a state where the portable terminal 2 is in close contact with the body, for example, in a pocket of clothes.

  The relationship between the reception level at each portable terminal 2 and the moving distance of the vehicle V1 when the vehicle V1 passes in front of the pedestrians Ha, Hb, Hc carrying the portable terminal 2 is shown in FIGS. Shown in The solid line in FIG. 4 (a) shows the reception level when the mobile terminal 2 is held in close contact with the body near the travel position of the vehicle V1, that is, the reception level of the mobile terminal 2 possessed by the pedestrian Hb and the vehicle movement. The relationship with distance is shown. On the other hand, the broken line in FIG. 4A indicates the reception level when the portable terminal 2 is carried away from the body and away from the body of the vehicle V1, that is, the portable possessed by the pedestrian Ha in the vicinity of the pedestrian Hb. The relationship between the reception level of the terminal 2 and a vehicle moving distance is shown.

  The solid line in FIG. 4B indicates the reception level when the mobile terminal 2 is carried away from the travel position of the vehicle V1 and away from the body, that is, the reception level of the mobile terminal 2 possessed by the pedestrian Hc and the vehicle travel distance. Shows the relationship. On the other hand, the broken line in FIG. 4B is similar to the broken line in FIG. 4A. The reception level when the mobile terminal 2 is carried away from the vehicle V1 and away from the body, that is, possessed by the pedestrian Ha. The relationship between the reception level of the portable terminal 2 and the vehicle travel distance is shown.

  The reception level when the mobile terminal 2 is carried in close contact with the body (reception level of the mobile terminal 2 possessed by the pedestrian Hb) shown by a solid line in FIG. 4A and the mobile terminal 2 shown by a broken line Both the reception level (the reception level of the mobile terminal 2 possessed by the pedestrian Ha) when the vehicle is held away from the body rises as the vehicle V1 approaches and shows a peak when approaching the vehicle V1. And after that, it drops as the vehicle V1 passes and the distance increases. That is, the reception level when the portable terminal 2 is held in close contact with the body has substantially the same shape (change gradient) as compared with the reception level when the portable terminal 2 is held away from the body. . However, as shown in FIG. 4A, when the portable terminal 2 is held in close contact with the body, the reception level is lowered as a whole. This is because the gain of the antenna 20 decreases due to the influence of the human body because the human body is a dielectric.

  In addition, the reception level of the mobile terminal 2 possessed by the pedestrian Hc located away from the travel route of the vehicle V1, as shown by the solid line in FIG. 4B, and the travel of the vehicle V1, shown by the broken line Both of the reception levels of the portable terminal 2 possessed by the pedestrian Ha located near the route rise as the vehicle V1 approaches, and show a peak when approaching most. And after that, it drops as the vehicle V1 passes and the distance increases. However, as shown in FIG. 4B, the reception level at a position away from the vehicle V1 has a smaller peak than the reception level at a position near the vehicle V1, and the change gradient near the peak is also low. small. This is because the pedestrian Hc is away from the travel route of the vehicle V1 and quickly deviates from the directional front of the antenna of the approach detection device 3 provided in the vehicle V1.

  Therefore, the reception level when the vehicle V1 passes by the side of the pedestrian Ha, Hb, Hc carrying the portable terminal 2 is recorded, and the peak value and the change shape (change gradient) are determined to determine the reception level. It can be determined whether the decrease is due to a decrease in the gain of the antenna or due to a distance from the vehicle V1. That is, compared with the peak value and change gradient of the reception level when the vehicle V1 passes in the vicinity of the portable terminal 2 held away from the body, the peak value is the same even though the change gradient is substantially the same. When it is low, it can be determined that the reception level is low because the wearing position of the mobile terminal 2 is close to the body.

  More specifically, the peak value Lmax of the reception level of the radio wave from the approach detection device 3 when the vehicle V1 passes, the change gradient X1 of the level value in the predetermined section R1 set before the peak, and the predetermined section A change gradient X2 in a predetermined section R2 (where R1 section length = R2 section length) that is farther from the peak position than R1 is calculated, and the peak value Lmax of the reception level is determined from the determination value (lower threshold) DL. When the ratio X1 / X2 between the change gradient X2 of the predetermined section R2 and the change gradient X1 of the predetermined section R1 is larger than the determination value DR, the reception level is lowered due to the mobile terminal 2 being brought closer to the body. It is judged that.

  For example, as indicated by a solid line in FIG. 4A, when the peak value Lbmax of the reception level is less than the determination value DL and the change gradient ratio Xb1 / Xb2 is larger than the determination value DR, the mobile terminal 2 Is judged to be in close contact with the body.

  On the other hand, as indicated by a solid line in FIG. 4B, when the peak value Lcmax of the reception level is less than the determination value DL and the change gradient ratio Xc1 / Xc2 is smaller than the determination value DR, the mobile terminal 2 It is determined that the position of the pedestrian Hc who holds the vehicle is away from the travel position of the vehicle V1.

  4A and 4B, when the mobile terminal 2 is held near the travel position of the vehicle V1 and away from the body, the peak value Lamax of the reception level is It becomes larger than the judgment value DL. That is, the determination value DL is obtained based on the relationship between the distance between the mobile terminal 2 and the body and the reception level reduction amount, and the relationship between the distance between the mobile terminal 2 and the vehicle and the reception level reduction amount, which are acquired in advance. It is larger than the peak value of the reception level when the distance between the mobile terminal 2 and the vehicle travel locus is long or when the mobile terminal 2 is brought close to the body, and the distance between the mobile terminal 2 and the vehicle travel locus is short and the mobile terminal. 2 is set to a value smaller than the peak value of the reception level when it is carried away from the body.

  Further, the determination value DR is received when the distance between the mobile terminal 2 and the vehicle travel locus is long, based on the relationship between the distance between the mobile terminal 2 and the body and the change gradient of the reception level acquired in advance. It is set to a value that is larger than the level change gradient ratio and smaller than the reception level change gradient ratio when the portable terminal 2 is held close to the body (one point shown in FIGS. 4A and 4B). (See chain line).

  Returning to FIG. 2, the description will be continued. As a result of the determination described above, when it is determined that the decrease in the reception level is caused by bringing the mobile terminal 2 closer to the body, the level correction value calculation unit 24 moves the mobile terminal 2 to the body of the pedestrian H. A level correction value for correcting the reduction amount of the reception level due to the approach is obtained. The level correction value is set in advance by measuring the relationship between the mounting position of the mobile terminal 2 and the amount of change in the reception level. An ID / level correction value sending unit 25 is connected to the level correction value calculating unit 24, and the obtained level correction value is output to the ID / level correction value sending unit 25.

  The ID and level correction value sending unit 25 adds the level correction value input from the level correction value calculation unit 24, the individually assigned mobile terminal ID, the received vehicle ID, and the like to the transmission data string in advance. A transmission data string that conforms to the determined communication format is generated and output to the transmission unit 26.

  The transmission unit 26 modulates a carrier wave based on the input transmission data string and outputs the modulated carrier wave to the antenna 20. As a result, transmission data including the level correction value is transmitted on the radio wave and transmitted from the antenna 20 to the approach detection device 3 mounted on the vehicle V2 that approaches next. That is, the transmission unit 26 functions as a transmission unit described in the claims.

  Subsequently, referring to FIG. 3, the level correction value is detected by receiving the radio wave from the portable terminal 2, the reception level is corrected using the level correction value, and the pedestrian is based on the corrected reception level. The configuration of the approach detection device 3 that estimates the position will be described.

  The approach detection device 3 has an antenna 30 for transmitting and receiving radio waves of a predetermined frequency. The radio wave from the portable terminal 2 received by the antenna 30 is demodulated by the receiving unit 31 and then output to the reception level and level correction value detecting unit 32. The reception level / level correction value detection unit 32 detects a reception level that is a state of reception of radio waves from the mobile terminal 2 and also detects a level correction value, mobile terminal ID information, and the like from the received data. That is, the receiving unit 31 and the reception level / level correction value detecting unit 32 function as terminal information receiving means described in the claims. The reception level / level correction value detector 32 also functions as a terminal reception level detector.

  A reception level correction / direction / distance estimation unit 33 is connected to the reception level / level correction value detection unit 32, and the detected reception level, level correction value, portable terminal ID information, and the like are received in this reception level correction / direction. Output to the distance estimation unit 33.

  The reception level correction / direction / distance estimation unit 33 is connected to a directivity control unit 38 that controls the directivity of the antenna 30 and an information provision determination unit 34. The reception level correction / direction / distance estimation unit 33 outputs azimuth information to be received to the directivity control unit 38. The directivity control unit 38 switches the directivity of the antenna 30 according to the azimuth information input from the reception level correction / direction / distance estimation unit 33. The reception level correction / direction / distance estimation unit 33 acquires reception levels in all directions by switching the directivity of the antenna 30. The directivity control unit 38 can control the directivity of the antenna 30 so that the radio wave is transmitted toward the estimated direction of the mobile terminal 2. The directivity control unit 38 can also set a region where radio waves are transmitted based on vehicle speed, turn signal information, and navigation information, which will be described later.

  The reception level correction / direction / distance estimator 33 estimates the arrival direction of radio waves from the mobile terminal 2 and the distance from the mobile terminal 2, that is, the position of the mobile terminal 2. The reception level correction / direction / distance estimation unit 33 determines the direction in which the reception level is maximum when the directivity of the antenna 30 is switched as the arrival direction of radio waves, that is, the direction in which a pedestrian carrying the mobile terminal 2 exists. presume.

  The reception level correction / direction / distance estimation unit 33 corrects the radio wave reception level using the level correction value detected by the reception level and level correction value detection unit 32. When the reception level is corrected, for example, the detected actual reception level and the level correction value are multiplied to calculate the corrected reception level. Then, the distance from the mobile terminal 2, that is, the distance from the pedestrian carrying the mobile terminal 2 is estimated from the corrected reception level. That is, the reception level correction / direction / distance estimation unit 33 functions as a correction unit and a distance calculation unit described in the claims.

  As described above, when the mobile terminal 2 is brought close to a human body, the antenna gain decreases. As a result, the reception level at the portable terminal 2 is lowered, and the transmission level from the portable terminal 2 is also lowered. Here, by correcting the reception level using the level correction value, the amount of decrease in the transmission level caused by bringing the mobile terminal 2 closer to the body of the pedestrian, that is, the amount of decrease in the reception level in the proximity detection device 3 Is corrected.

  Further, as described above, the information provision determination unit 34 is connected to the reception level correction / direction / distance estimation unit 33. The direction information of the pedestrian H carrying the mobile terminal 2 estimated by the reception level correction / direction / distance estimation unit 33 and the distance information from the pedestrian H are sent to the information provision determination unit 34. In addition to the direction / distance information, the information provision determination unit 34 includes information on the speed (vehicle speed) of the own vehicle detected using a vehicle speed sensor, turn signal information indicating the state of the turn signal indicator, Navigation information such as road shape, road width, intersection information, and lane number information in the vicinity of the current position of the vehicle (particularly in the forward direction) obtained from the navigation system is supplied. The navigation information is stored in advance in the map database of the navigation system.

  On the other hand, a pedestrian presence information provision area table 35 is connected to the information provision determination unit 34. In the pedestrian presence information provision area table 35, information on a pedestrian presence information provision area in which different areas are set using vehicle speed, blinker information, and navigation information as parameters is written in advance. Based on the acquired vehicle speed, turn signal information, and navigation information of the subject vehicle, the information provision determination unit 34 selects a pedestrian presence information provision area corresponding to the vehicle speed, turn signal information, and navigation information from the pedestrian presence information provision area table 35. A person who holds the portable terminal 2 in the read pedestrian presence information provision area based on the direction and distance of the person sent from the reception level correction / direction / distance estimation unit 33 after reading. It is determined whether or not to do so. In addition, the pedestrian presence information providing area information is not previously stored in the pedestrian presence information providing area table 35, but the pedestrian presence information providing areas corresponding to these parameters are sequentially derived according to a predetermined calculation formula. May be.

  In addition, the information provision determination unit 34 is connected to an information provision unit 36 that visually or audibly provides information to the driver of the host vehicle using a display or a speaker. When it is determined that a person is present in the pedestrian presence information provision area, the information provision determination unit 34 provides an instruction for notifying the vehicle driver that the person is present in the pedestrian presence information provision area. This is performed for the providing unit 36. When the information providing unit 36 receives an information providing instruction from the information providing determining unit 34, the information providing unit 36 operates a display or a speaker, so that a person exists in the pedestrian presence information providing area for the own vehicle and the own vehicle is Inform the vehicle driver that there is a potential for human contact.

  Furthermore, the information provision determination unit 34 is connected to a transmission unit 37 that transmits information for notifying the mobile terminal 2 of the approach of the vehicle. When it is determined that there is a person in the pedestrian presence information provision area, the information provision determination unit 34 is in the pedestrian presence information provision area from the ID of the mobile terminal 2 acquired by the reception unit 31. The transmission unit 37 is instructed to transmit the ID and danger information of the portable terminal 2. When receiving an ID transmission instruction, the transmission unit 37 transmits the ID and danger information of the mobile terminal 2 in the pedestrian presence information provision area from the antenna 30 on radio waves.

  Next, operations of the mobile terminal 2 and the approach detection device 3, that is, operations of the approach detection system 1 will be described with reference to FIGS. 5 and 6. FIG. 5 is a flowchart showing a processing procedure of level correction value calculation processing by the mobile terminal 2. This level correction value calculation process is repeatedly executed at a predetermined timing from when the power of the portable terminal 2 is turned on to when it is turned off. FIG. 6 is a flowchart showing a processing procedure of pedestrian direction / distance estimation processing by the approach detection device 3. This pedestrian direction / distance estimation process is repeatedly executed at a predetermined timing from when the power of the approach detection device 3 is turned on until it is turned off.

  In step S100 shown in FIG. 5, the reception level of the radio wave from the approach detection device 3 mounted on the vehicle V1 and the vehicle speed information of the vehicle V1 in the received data are acquired, and the vehicle calculated from the vehicle speed information. The relationship between the moving distance of V1 and the reception level is recorded (see FIG. 4).

  Subsequently, in step S102, a determination is made as to whether or not radio waves from the vehicle V1 can no longer be received for a predetermined time Ta (for example, several seconds) or longer. Here, when the radio wave from the vehicle V1 cannot be received for a predetermined time Ta or more, it is determined that the vehicle V1 has passed and has left the pedestrian carrying the mobile terminal 2, and the process proceeds to step S104. On the other hand, if step S102 is negative, the process proceeds to step S100, and steps S100 and S102 are repeatedly executed while radio waves cannot be received for a predetermined time Ta or longer.

  In step S104, the peak value Lmax of the reception level recorded in step S100 and the reception level change gradients X1 and X2 of the sections R1 and R2 described above are obtained.

  In the subsequent step S106, it is determined whether or not the peak value Lmax of the reception level is smaller than the determination value DL. Here, when the peak value Lmax of the reception level is equal to or greater than the determination value DL, it is determined that the reception level has not decreased, and the reception level resulting from the mobile terminal 2 being brought closer to the body in step S108. After the level correction value HL for correcting the amount of decrease is set to zero, the process proceeds to step S116. On the other hand, when the peak value Lmax of the reception level is smaller than the determination value DL, the process proceeds to step S110.

  In step S110, a determination is made as to whether or not the reception level change gradient ratio X1 / X2 is greater than the determination value DR. Here, when the change gradient ratio X1 / X2 of the reception level is equal to or less than the determination value DR, it is determined that the decrease in the reception level is caused by the distance between the mobile terminal 2 and the vehicle V1 being increased. The process proceeds to S112. On the other hand, when the change gradient ratio X1 / X2 is larger than the determination value DR, it is determined that the decrease in the reception level is caused by bringing the mobile terminal 2 closer to the body (due to the decrease in the gain of the antenna), and the process proceeds to step S114. Processing shifts.

  In step S112, since the decrease in the reception level is caused by the distance between the portable terminal 2 and the vehicle V1, the previous value is held without updating the level correction value HL. Thereafter, the process proceeds to step S116.

  In step S114, since the decrease in the reception level is caused by bringing the mobile terminal 2 closer to the body, the correction value h1 is set as the level correction value HL for correcting the decrease in the reception level. Thereafter, the process proceeds to step S116.

  On the other hand, in step S116, the level correction value HL set in step S108, S112, or S114 is output to the ID / level correction value sending unit 25. Then, as described above, after being added to the transmission data string in the ID and level correction value sending unit 25, it is sent via the sending unit 26 to the approach detection device 3 mounted on the next approaching vehicle V2. Thereafter, the process is temporarily exited.

  Next, the operation of the approach detection device 3 will be described with reference to the flowchart showing the processing procedure of the pedestrian direction / distance estimation processing shown in FIG. The pedestrian direction / distance estimation process is executed by the reception level correction / direction / distance estimation unit 33 constituting the approach detection device 3.

  In step S200, the reception level of all directions obtained by oscillating the directivity of the antenna 30 is read, and the direction in which the reception level is maximum is the arrival direction of the radio wave emitted from the mobile terminal 2, that is, the mobile terminal 2 It is presumed that the pedestrian H possessed is in the direction.

  Next, in step S202, the reception level and the level correction value HL detected by the level correction value detector 32 are first read. Subsequently, the level correction value HL is multiplied by the reception level read in step S200 to calculate a corrected reception level. Then, the distance from the mobile terminal 2, that is, the distance from the pedestrian H carrying the mobile terminal 2 is estimated according to the corrected reception level.

  In subsequent step S204, the direction of the pedestrian H carrying the mobile terminal 2 estimated in step S200 and the distance to the pedestrian H estimated in step S202 are output to the information provision determination unit 34.

  According to the portable terminal 2 constituting the proximity detection system 1 according to the present embodiment, when the peak value Lmax of the reception level is smaller than the determination value DL, the reception level is reduced based on the change gradient ratio X1 / X2 of the reception level. Is due to a decrease in the gain of the antenna 20 or due to a greater distance from the vehicle V1. When it is determined that the decrease in the reception level is due to the decrease in the gain of the antenna 20, a level correction value HL for correcting the amount of decrease in the reception level caused by bringing the mobile terminal 2 closer to the body is obtained. In addition, the level correction value HL is transmitted to the approach detection device 3 mounted on the vehicle V2.

  On the other hand, in the proximity detection device 3 mounted on the vehicle V2, the reception level of the radio wave emitted from the mobile terminal 2 is corrected using the level correction value HL, and the distance from the mobile terminal 2 is based on the corrected reception level. Is required.

  As a result, according to the proximity detection system 1 according to this embodiment configured to include the mobile terminal 2 and the proximity detection device 3, the reception level due to the proximity of the mobile terminal 2 being close to the body in the proximity detection device 3. Therefore, the distance between the pedestrian H carrying the mobile terminal 2 and the vehicle V2 on which the approach detection device 3 is mounted can be accurately estimated.

  Next, another processing mode (second processing mode) of level correction value calculation processing by the portable terminal 2 will be described with reference to FIG. FIG. 7 is a flowchart showing the second processing form. This level correction value calculation process is also repeatedly executed at a predetermined timing from when the power of the portable terminal 2 is turned on to when it is turned off.

  This second processing mode is different from the above-described processing procedure in that level correction value averaging processing (steps S316 and S318) is added. Therefore, steps S300 to S314 are the same as or similar to the above-described steps S100 to S114, and thus description thereof is omitted here.

  In step S316, n (for example, about 3 to 5) level correction values HL 'that have been set most recently in step S308, S312 or S314 are stored. Subsequently, in step S318, an average value (hereinafter referred to as “level correction average value”) HHL of the n level correction values HL ′ stored in step S316 is calculated. In step S320, the level correction average value HHL calculated in step S318 is output to the ID and level correction value sending unit 25. As a result, as described above, the level correction average value HHL is added to the transmission data string in the ID and level correction value sending unit 25, and the approach detection device 3 mounted on the vehicle V2 that approaches next through the transmission unit 26. Sent to.

  According to this processing mode, it is possible to further improve the accuracy of the level correction value by averaging the level correction value.

  In the above-described embodiment, when the level correction value HL is obtained, vehicle speed information is received from the approach detection device 3 mounted on the vehicle V1, and the moving distance of the vehicle V1 is calculated from the vehicle speed information. The relationship between the reception level and the moving distance of the vehicle V1 is graphed (see FIGS. 4A and 4B), and the reception level decreases based on the graphed reception level peak value and change gradient. It was determined whether or not it was caused by bringing 2 close to the body. On the other hand, without obtaining the vehicle speed information, the relationship between the reception level and the elapsed time at the portable terminal 2 is graphed, and the reception level is lowered based on the peak value and change gradient of the graphed reception level. It is also possible to determine whether or not this is caused by bringing the mobile terminal 2 close to the body, and a level correction value can be set.

  Here, referring to FIGS. 8A and 8B, it is determined whether or not the decrease in the reception level is caused by bringing the mobile terminal 2 closer to the body without using the vehicle speed information. A method for setting the level correction value will be described. The solid line in FIG. 8A shows the relationship between the reception level and the elapsed time when the mobile terminal 2 is held in close contact with the body near the travel position of the vehicle V1. On the other hand, the broken line in FIG. 8A shows the relationship between the reception level and the elapsed time when the mobile terminal 2 is held near the travel position of the vehicle V1 and away from the body. The solid line in FIG. 8B shows the relationship between the reception level and the elapsed time when the mobile terminal 2 is carried away from the body and away from the travel position of the vehicle V1. On the other hand, the broken line in FIG. 8B shows the relationship between the reception level and the elapsed time when the portable terminal 2 is held close to the traveling position of the vehicle V1 and away from the body, like the broken line in FIG. Show.

  In this method, first, a section R1 ′ is defined between a time tp at which the reception level indicates the peak value Lmax ′ and a time t1 ′ at which the reception level is a predetermined level Ls lower than the peak value Lmax ′. A section R2 ′ is defined between t1 ′ and a time t2 ′ separated from the peak position by a time equal to the elapsed time in the section R1 ′. Next, the level value change gradient X1 'in the section R1' and the change gradient X2 'in the section R2' are calculated. When the peak value Lmax of the reception level is smaller than the determination value DL ′ and the ratio X1 / X2 between the change gradient X2 of the predetermined section R2 and the change gradient X1 of the predetermined section R1 is larger than the determination value DR ′, the reception is performed. It is determined that the decrease in level is due to the mobile terminal 2 being brought closer to the body.

  For example, as indicated by a solid line in FIG. 8A, when the peak value Lbmax ′ of the reception level is less than the determination value DL ′ and the change gradient ratio Xb1 ′ / Xb2 ′ is greater than the determination value DR ′. It is determined that the portable terminal 2 is held in close contact with the body. Note that the method for obtaining the level correction value is the same as or similar to the above-described case, and thus the description thereof is omitted here.

  On the other hand, as indicated by a solid line in FIG. 8B, the peak value Lcmax ″ of the reception level is less than the determination value DL ′, and the change gradient ratio Xc1 ″ / Xc2 ″ is greater than the determination value DR ′. If it is smaller, it is determined that the position of the pedestrian carrying the mobile terminal 2 is away from the travel position of the vehicle V1.

  In this way, the level correction value HL can be easily obtained without using vehicle speed information.

  Here, FIGS. 8A and 8B show the relationship between the elapsed time when the vehicle V1 passes in front of the pedestrian at a substantially constant vehicle speed and the reception level at the portable terminal 2. FIG. Since the horizontal axis is the elapsed time, the graph extends or contracts in the horizontal axis direction when the vehicle speed changes. That is, when the vehicle speed is high, the graph contracts in the horizontal axis direction, and when the vehicle speed is low, the graph extends in the horizontal axis direction. However, it is possible to appropriately determine whether or not the decrease in the reception level is caused by bringing the mobile terminal 2 closer to the body by comparing with the change gradient ratio. Note that, when the vehicle speed changes during the passage, the gradient of change in the reception level also changes, but an appropriate level correction value can be obtained by taking the average value of the level correction values obtained from a plurality of in-vehicle devices.

  Next, the configurations of the proximity detection system 4 according to the second embodiment, the mobile terminal 5 that constitutes the proximity detection system 4, and the proximity detection device 3 will be described with reference to FIGS. FIG. 9 is a diagram illustrating a configuration of the approach detection system 4. FIG. 10 is a block diagram of the mobile terminal 5.

  As shown in FIG. 9, the approach detection system 4 is different from the approach detection system 1 described above in that the approach detection system 4 includes a mobile terminal 5 instead of the mobile terminal 2. Also, as shown in FIG. 10, the mobile terminal 5 has an antenna 27 (for example, a loop antenna) whose gain is improved by being close to a human body, and a level correction value corresponding to this antenna characteristic. It differs from the above-described portable terminal 2 in that a calculation program is stored. Other configurations are the same as or similar to those described above, and a description thereof is omitted here. In addition, since the approach detection apparatus 3 which comprises the approach detection system 4 is the same as that of what was mentioned above, or is the same, it abbreviate | omits description here.

  Here, with reference to FIG. 11, a method for determining whether or not the improvement of the reception level is caused by holding the portable terminal 5 close to the body will be described. Here, as shown in FIG. 9, the vehicle V3 approaches from the right direction of the pedestrian Hd, He carrying the mobile terminal 5 (right diagonally forward of the pedestrian Hf), and forward of the pedestrian Hd, He, Hf. The case of passing through will be described as an example. The vehicle V3 is assumed to travel along the traveling direction indicated by the alternate long and short dash line in FIG. Since the pedestrians Hd and He are located near the traveling direction of the vehicle V3, the vehicle V3 passes close to the pedestrians Hd and He. On the other hand, the pedestrian Hf is located at a location farther away from the traveling direction of the vehicle V3 than the pedestrians Hd and He. Therefore, the vehicle V3 passes through a place away from the pedestrian Hf.

  The pedestrian Hd and the pedestrian Hf carry the mobile terminal 5 away from the body, for example, attached to a bag. On the other hand, the pedestrian Hd is in a state where the portable terminal 5 is in close contact with the body, for example, in a pocket of clothes.

  11A and 11B show the relationship between the reception level at each portable terminal 5 and the moving distance of the vehicle V3 when the vehicle V3 passes in front of the pedestrians Hd, He, and Hf carrying the portable terminal 5. Shown in The solid line in FIG. 11A shows the reception level when the mobile terminal 5 is held close to the vehicle V3 and in close contact with the body, that is, the reception level of the mobile terminal 5 carried by the pedestrian He and the vehicle movement. The relationship with distance is shown. On the other hand, the broken line in FIG. 11A indicates the reception level when the portable terminal 5 is carried near the vehicle V3 and away from the body, that is, the portable carried by the pedestrian Hd in the vicinity of the pedestrian He. The relationship between the reception level of the terminal 5 and a vehicle moving distance is shown.

  The solid line in FIG. 11B indicates the reception level when the mobile terminal 5 is carried away from the travel position of the vehicle V3 and away from the body, that is, the reception level of the mobile terminal 5 possessed by the pedestrian Hf and the vehicle travel distance. Shows the relationship. On the other hand, the broken line in FIG. 11 (b) is similar to the broken line in (a), the reception level when the portable terminal 5 is carried away from the vehicle V3 and away from the body, that is, possessed by the pedestrian Hd. The relationship between the reception level of the portable terminal 5 and the vehicle travel distance is shown.

  The reception level when the mobile terminal 5 is held in close contact with the body (reception level of the mobile terminal 5 possessed by the pedestrian He) shown by the solid line in FIG. 11A and the mobile terminal 5 shown by the broken line Both the reception level when the mobile phone is carried away from the body (the reception level of the portable terminal 5 possessed by the pedestrian Hd) rises as the vehicle V3 approaches, and shows a peak when the vehicle V3 is closest. And after that, it falls as the vehicle V3 passes and the distance increases. In other words, the reception level when the mobile terminal 5 is held in close contact with the body has substantially the same shape (change gradient) as compared with the reception level when the mobile terminal 5 is held away from the body. . However, as shown in FIG. 11A, when the portable terminal 5 is held in close contact with the body, the reception level is improved as a whole. This is because the gain of the antenna 20 is improved by the influence of the human body because the human body is a dielectric.

  Further, the reception level of the mobile terminal 5 possessed by the pedestrian Hf located away from the travel route of the vehicle V3, which is indicated by a solid line in FIG. 11B, and the travel of the vehicle V3, which is indicated by a broken line. Both the reception levels of the portable terminals 5 possessed by the pedestrian Hd located near the route rise as the vehicle V3 approaches, and show a peak when approaching most. And after that, it falls as the vehicle V3 passes and the distance increases. However, as shown in FIG. 11B, the reception level at a position away from the vehicle V3 has a smaller peak than the reception level at a position near the vehicle V3, and the change gradient near the peak is also low. small. This is because the pedestrian Hf is away from the travel route of the vehicle V3 and quickly deviates from the directional front of the antenna of the approach detection device 3 provided in the vehicle V3.

  Therefore, the reception level when the vehicle V3 passes by the pedestrians Hd, He, and Hf carrying the portable terminal 5 is recorded, and the peak value and the change shape (change gradient) are determined to determine the reception level. It can be determined whether or not the improvement is due to an increase in antenna gain. That is, when the peak value of the reception level is high and the change gradient is substantially the same, it can be determined that the reception level is improved because the wearing position of the mobile terminal 5 is close to the body.

  More specifically, the peak value Lmax of the reception level of the radio wave from the approach detection device 3 when the vehicle V3 passes, the level value change gradient X1 in the predetermined section R1 set before the peak, and the predetermined section A change gradient X2 in a predetermined section R2 (where R1 section length = R2 section length) farther from the peak position than R1 is calculated, and the peak value Lmax of the reception level is determined from the determination value (upper limit threshold value) DL2. When the ratio X1 / X2 between the change gradient X2 of the predetermined section R2 and the change gradient X1 of the predetermined section R1 is larger than the determination value DR2, the reception level is improved by bringing the mobile terminal 5 closer to the body. It is judged that.

  For example, as indicated by a solid line in FIG. 11A, when the peak value Lemax of the reception level is larger than the determination value DL2 and the change gradient ratio Xe1 / Xe2 is larger than the determination value DR2, the mobile terminal 5 Is judged to be in close contact with the body.

  11A and 11B, when the portable terminal 5 is carried away from the body, the peak value Ldmax of the reception level is smaller than the determination value DL2. That is, the determination value DL2 is based on the relationship between the distance between the mobile terminal 5 and the body and the reception level improvement amount and the relationship between the distance between the mobile terminal 5 and the vehicle and the reception level improvement amount acquired in advance. It is larger than the peak value of the reception level when the distance between the mobile terminal 5 and the vehicle travel locus is large or when the mobile terminal 5 is separated from the body, and the distance between the mobile terminal 5 and the vehicle travel locus is short and portable. It is set to a value smaller than the peak value of the reception level when the terminal 5 is held in close contact with the body.

  The determination value DR2 is received when the distance between the mobile terminal 5 and the vehicle travel locus is long based on the relationship between the distance between the mobile terminal 5 and the body and the change gradient of the reception level that is acquired in advance. It is set to a value that is larger than the change gradient ratio of the level and smaller than the change gradient ratio of the reception level when the portable terminal 5 is held close to the body (one point shown in FIGS. 11A and 11B). (See chain line).

  Next, the operation of the mobile terminal 5 will be described with reference to FIG. FIG. 12 is a flowchart showing a processing procedure of level correction value calculation processing by the mobile terminal 5. This level correction value calculation process is repeatedly executed at a predetermined timing from when the power of the mobile terminal 5 is turned on to when it is turned off.

  Steps S400 to S404 are the same as or similar to Steps S100 to S104 described above, and thus the description thereof is omitted here.

  In step S406, a determination is made as to whether or not the reception level change gradient ratio X1 / X2 is greater than the determination value DR2. Here, if the change gradient ratio X1 / X2 of the reception level is equal to or smaller than the determination value DR2, the previous value is held without updating the level correction value HL in step S112. Thereafter, the process proceeds to step S416. On the other hand, when the change gradient ratio X1 / X2 is larger than the determination value DR2, the process proceeds to step S410.

  In step S410, a determination is made as to whether or not the peak value Lmax of the reception level is greater than the determination value DL2. Here, when the peak value Lmax of the reception level is equal to or smaller than the determination value DL2, it is determined that the reception level has not improved, and in step S412, the reception level due to the mobile terminal 5 being brought close to the body is determined. After the level correction value HL for correcting the improvement amount is set to zero, the process proceeds to step S416. On the other hand, when the peak value Lmax of the reception level is larger than the determination value DL2, it is determined that the improvement of the reception level is caused by bringing the mobile terminal 5 closer to the body (due to the improvement of the antenna gain). Processing shifts.

  In step S414, the correction value h2 is set to the level correction value HL for correcting the improvement amount of the reception level. Thereafter, the process proceeds to step S416.

  In step S416, the level correction value HL set in step S408, S412, or S414 is output to the ID / level correction value sending unit 25. Then, as described above, after being added to the transmission data string in the ID / level correction value sending unit 25, it is sent to the approach detection device 3 mounted on the next approaching vehicle V <b> 4 via the sending unit 26. Thereafter, the process is temporarily exited.

  According to the mobile terminal 5 constituting the proximity detection system 4 according to the present embodiment, the reception level change gradient ratio X1 / X2 is larger than the determination value DR2, and the reception level peak value Lmax is larger than the determination value DL2. If it is larger, it is determined that the improvement of the reception level is due to the improvement of the gain of the antenna 27. Then, a level correction value HL for correcting the amount of improvement in reception level caused by bringing the mobile terminal 5 close to the body is obtained, and this level correction value HL is obtained in the approach detection device 3 mounted on the vehicle V4. Sent.

  On the other hand, in the approach detection device 3 mounted on the vehicle V4, the reception level of the radio wave emitted from the mobile terminal 5 is corrected using the level correction value HL, and the distance from the mobile terminal 5 based on the corrected reception level. Is required.

  As a result, according to the proximity detection system 2 according to the present embodiment configured to include the mobile terminal 5 and the proximity detection device 3, in the proximity detection device 3, the reception level caused by bringing the mobile terminal 5 close to the body. Therefore, the distance between the pedestrian H carrying the portable terminal 5 and the vehicle V4 on which the approach detection device 3 is mounted can be accurately estimated.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above embodiment, based on the ratio of the change gradient of the reception level, it is determined whether or not the decrease in the reception level is caused by holding the mobile terminal 2 close to the body, Although the correction value is set, the level correction value may be set based on the absolute value of the reception level change gradient.

  Moreover, in the said embodiment, although the level correction value was set in two steps, you may set in multiple steps according to the magnitude | size of a peak value. In this case, the level correction value is set to a larger value as the level difference between the peak value and the determination value DL is larger.

  Furthermore, when calculating the level correction average value by taking the average of each level correction value acquired from a plurality of passing vehicles, for example, to increase the weighting of vehicles with a short elapsed time after passing, You may make it average by weighting temporally.

  In the above embodiment, the intermittent transmission wave from the mobile terminal 2 is received by the directional antenna of the approach detection device 3 mounted on the vehicle, and the position of the pedestrian is estimated. The transmission wave may be received by the portable terminal 2, the reception level value and the level correction value may be sent back to the approach detection device 3 side, and the position of the pedestrian may be estimated based on those values.

  Moreover, in the said embodiment, in order to estimate the direction where the pedestrian who has the portable terminal 2 exists, the directivity of the antenna 30 was used, However, As shown in FIG. It may be.

  In the second processing mode, the level correction value is averaged. When the peak value of the reception level and the deviation of the change gradient ratio in the portable terminal 2 are within a predetermined range, that is, the pedestrian and the vehicle. The averaging process may be executed only when there is no significant change in the distance or the possession state of the mobile terminal 2. In this way, it is possible to further improve the reception level correction accuracy based on the level correction value.

It is a figure which shows the structure of the approach detection system which concerns on 1st Embodiment. It is a block diagram of the portable terminal which comprises the approach detection system which concerns on 1st Embodiment. It is a block diagram of the approach detection apparatus which comprises the approach detection system which concerns on 1st Embodiment. (A) is a graph which shows the relationship between the vehicle moving distance at the time of making a portable terminal closely_contact | adhere to a body, and a reception level. (B) is a graph showing the relationship between the vehicle travel distance and the reception level when the distance is large. It is a flowchart which shows the process sequence of a level correction value calculation process. It is a flowchart which shows the process sequence of a pedestrian direction / position estimation process. It is a flowchart which shows the other process sequence of a level correction value calculation process. (A) is a graph which shows the relationship between the elapsed time at the time of making a portable terminal closely_contact | adhere to a body, and a reception level. (B) is a graph showing the relationship between the elapsed time and the reception level when the distance is large. It is a figure which shows the structure of the approach detection system which concerns on 2nd Embodiment. It is a block diagram of the portable terminal which comprises the approach detection system which concerns on 2nd Embodiment. (A) is a graph which shows the relationship between the vehicle moving distance at the time of making a portable terminal closely_contact | adhere to a body, and a reception level. (B) is a graph showing the relationship between the vehicle travel distance and the reception level when the distance is large. It is a flowchart which shows the process sequence of a level correction value calculation process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,4 ... Approach detection system, 2,5 ... Portable terminal, 3 ... Approach detection apparatus, 20, 27 ... Antenna, 21 ... Reception part, 22 ... Reception level, ID, vehicle speed detection part, 23 ... Information provision part, 24 ... level correction value calculation unit, 25 ... ID, level correction value transmission unit, 26 ... transmission unit, 30 ... antenna, 31 ... reception unit, 32 ... reception level, level correction value detection unit, 33 ... reception level correction / direction Distance estimation part 34 ... Information provision determination part 35 ... Pedestrian presence information provision area table 36 ... Information provision part 37 ... Transmission part 38 ... Directivity control part

Claims (7)

In a mobile terminal provided with a receiving means and a transmitting means for performing wireless communication with an approach detection device mounted on a moving body,
Reception level detection means for detecting the reception level of the radio wave received by the reception means;
Correction value calculation means for obtaining a level correction value for correcting the reception level based on a peak value and a change gradient of the reception level when the mobile body passes,
The portable terminal characterized in that the transmission means transmits the level correction value.   The correction value calculation means, when the peak value of the reception level is out of a predetermined range and the change slope of the reception level is larger than a predetermined slope, the level correction value according to the change slope of the reception level. The mobile terminal according to claim 1, wherein:   The correction value calculating means, when the peak value of the reception level is smaller than a lower limit threshold and the change gradient of the reception level is larger than a predetermined gradient, the correction value calculation means according to the change gradient of the reception level. The mobile terminal according to claim 1, wherein a level correction value is obtained.   The correction value calculating means, when the peak value of the reception level is larger than an upper limit threshold and the change gradient of the reception level is larger than a predetermined gradient, according to the change gradient of the reception level. The mobile terminal according to claim 1, wherein a level correction value is obtained.   The said correction value calculating means calculates | requires the level correction value about several moving bodies, and calculates the said level correction value by averaging this several level correction value, The any one of Claims 1-4 characterized by the above-mentioned. The mobile terminal according to item 1. In an approach detection device that is mounted on a mobile body, performs wireless communication with the mobile terminal according to any one of claims 1 to 5, and detects an approaching state with the mobile terminal.
A terminal information receiving means for obtaining the level correction value by receiving radio waves emitted from the mobile terminal,
Terminal reception level detection means for detecting the reception level of radio waves from the mobile terminal received by the terminal information reception means;
Correction means for correcting the reception level detected by the terminal reception level detection means based on the level correction value;
A distance calculating means for obtaining a distance from the portable terminal based on the corrected reception level. The mobile terminal according to any one of claims 1 to 5,
An approach detection system comprising: the approach detection apparatus according to claim 6.

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