Vehicle communication system

Abstract

To increase detection precision of a position of a portable machine in a vehicle communication system.SOLUTION: A vehicle communication system comprises: multiple on-vehicle antennas 10 for transmitting and receiving electric waves in a predetermined band; and a control section 20 for controlling transmission / reception by the multiple on-vehicle antennas 10. The control section 20 determines whether a reflector 4 for reflecting electric waves in a predetermined band to the outside of a vehicle 1 exists. Then, the control section 20 calculates a position of a portable machine 3 by using multiple distance measurement values measured by radio communication between the multiple on-vehicle antennas 10 and the portable machine 3 each when no reflectors 4 exist outside the vehicle 1. In contrast, the control section 20 calculates the distance between a vehicle and the reflector 4 when the reflector 4 exists outside the vehicle 1, and calculates the position of the portable machine 3 by using multiple distance measurement values measured each by radio communication between the multiple on-vehicle antennas 10 and the portable machine 3, and distance L between the vehicle 1 and the reflector 4.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle communication system that detects the location of a portable device carried by a vehicle user by wirelessly communicating with the portable device. [Background technology]

[0002] Patent Document 1 discloses a system for identifying a person who has brought a mobile device such as a smartphone into a monitored space. This system determines that a person is carrying a mobile device if the difference between the theoretical value of the radio waves emitted from the mobile device and received by a receiving device when the person is assumed to be carrying the mobile device and the actual measured value of the radio waves received by the receiving device is smaller than a predetermined value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-063961 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology described in Patent Document 1 calculates the theoretical value of radio waves transmitted from a portable device and received by a receiving device, so it is necessary to know in advance the positions of reflectors in the monitored space, the reflectivity of radio waves by the reflectors, the position of the receiving device, etc. Therefore, this technology is only applicable to monitored spaces where the positions of reflectors, the reflectivity of radio waves by the reflectors, and the position of the receiving device are fixed. In contrast, in a vehicle communication system that detects the position of a portable device carried by a vehicle user, the presence or absence of reflectors that reflect radio waves from the portable device and the distance between the reflectors and the vehicle change depending on the vehicle's surrounding environment. Therefore, the technology described in Patent Document 1 is of no use in vehicle communication systems.

[0005] In view of the above, an object of the present disclosure is to improve the accuracy of detecting the position of a portable device in a vehicle communication system. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, a vehicle communication system that wirelessly communicates with a portable device (3) carried by a user (2) of a vehicle (1), detects the location of the portable device, and controls the vehicle, comprises: a plurality of vehicle-mounted antennas (10) mounted on a vehicle for transmitting and receiving radio waves in a predetermined band; a control unit (20) that controls transmission and reception by a plurality of vehicle-mounted antennas; The control unit determining whether or not there is a reflector (4) outside the vehicle that reflects radio waves in a predetermined band; If there is no reflector outside the vehicle, the position of the portable device is calculated using a plurality of distance measurement values ​​obtained by wireless communication between the plurality of vehicle-mounted antennas and the portable device; If a reflector is present outside the vehicle, the distance (L) between the vehicle and the reflector is calculated, and the position of the portable device is calculated using multiple distance measurements obtained by wireless communication between multiple vehicle-mounted antennas and the portable device, and the distance between the vehicle and the reflector.

[0007] According to this, the control unit can determine whether or not a reflector is present outside the vehicle, thereby calculating the position of the portable device with high accuracy both when a reflector is not present and when a reflector is present. Furthermore, when a reflector is present outside the vehicle, the control unit can detect the position of the portable device with high accuracy by using the distance between the vehicle and the reflector, even if the distance measurement value obtained by wireless communication between the vehicle-mounted antenna and the portable device is due to a wave reflected by the reflector. Therefore, this vehicular communication system can perform vehicle control according to the accurate position of the portable device.

[0008] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing a vehicle equipped with a vehicle communication system according to a first embodiment, a portable device carried by a user, and a reflector. [Figure 2] 3 is a flowchart showing a control process executed by a control unit included in the vehicle communication system according to the first embodiment. [Figure 3] 3 is a flowchart showing the process of S20 in FIG. 2 in detail. [Figure 4] FIG. 10 is an explanatory diagram for explaining distance measurement of a reflector by transmitting and receiving signals from a single vehicle-mounted antenna. [Figure 5] This is a distribution diagram of "distance measurement value-frequency" when there is no reflector in front of the vehicle-mounted antenna. [Figure 6] This is a distribution diagram of "distance measurement value-frequency" when a reflector is present in front of the vehicle-mounted antenna. [Figure 7] 10 is an explanatory diagram for explaining distance measurement of a reflector by transmitting and receiving signals between a plurality of vehicle-mounted antennas; FIG. [Figure 8] This is a distribution diagram of "distance measurement value-frequency" when there is no reflector in the area between multiple vehicle-mounted antennas. [Figure 9] This is a distribution diagram of "distance measurement value-frequency" when a reflector is present in the area between multiple vehicle-mounted antennas. [Figure 10] FIG. 3 is an explanatory diagram for explaining the process of S50 in FIG. 2. [Figure 11] 3 is a flowchart showing the details of the processes of S80 to S110 in FIG. 2. [Figure 12] FIG. 12 is an explanatory diagram for explaining the process of S901 in FIG. [Figure 13] FIG. 10 is an explanatory diagram for explaining Equation 3. [Figure 14] FIG. 12 is an explanatory diagram for explaining the process of S903 in FIG. [Figure 15] FIG. 12 is an explanatory diagram for explaining the processing of S904 in FIG. [Figure 16] FIG. 12 is an explanatory diagram for explaining the process of S905 in FIG. [Figure 17] FIG. 10 is a schematic diagram showing a vehicle equipped with a vehicle communication system according to a second embodiment, and a reflector. [Figure 18] FIG. 10 is an explanatory diagram for explaining Equations 4 and 5. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, identical or equivalent parts will be denoted by the same reference numerals, and description thereof will be omitted.

[0011] (First embodiment) A first embodiment will be described with reference to the drawings. The vehicle communication system of the first embodiment is a system that detects the location of a portable device 3 carried by a user 2 of a vehicle 1 by wirelessly communicating with the portable device 3 and performs unlocking, locking, or welcome control of the vehicle 1. Specifically, the vehicle communication system is capable of detecting the location of the portable device 3 with high accuracy using BLECS ranging technology. BLE is an abbreviation for Bluetooth (registered trademark) Low Energy, and CS is an abbreviation for channel sounding.

[0012] As shown in FIG. 1, the vehicle communication system includes a plurality of on-board antennas 10 mounted on a vehicle 1 and a control unit 20. The plurality of on-board antennas 10 are, for example, BLE antennas. The BLE antenna has a ranging function using wireless communication in a communication method conforming to the BLE standard. The plurality of on-board antennas 10 are installed, for example, at the front, rear, left, and right of the vehicle 1, and transmit and receive radio waves in a predetermined band (for example, the 2.4 GHz band). In the following description, of the plurality of on-board antennas 10, the on-board antenna 10 installed at the rear right of the vehicle may be referred to as a first antenna 11 as appropriate, and the on-board antenna 10 installed at the front right of the vehicle may be referred to as a second antenna 12 as appropriate.

[0013] The control unit 20 is mainly composed of a microcomputer having a processor that performs control processing and arithmetic processing, and a memory that stores programs, data, etc. The processor is composed of a CPU and an MPU. The memory includes various non-transient tangible storage media such as ROM, RAM, and non-volatile rewritable memory. The control unit 20 controls transmission and reception by the multiple on-board antennas 10 by the processor executing the program stored in the memory, and calculates the position of the portable device 3 from distance measurements obtained by wireless communication between the multiple on-board antennas 10 and the portable device 3.

[0014] The portable device 3 carried by the user 2 of the vehicle 1 is, for example, a smartphone or an electronic key. The portable device 3 has a portable device antenna 30 and a portable device control unit 31. The portable device antenna 30 is also, for example, a BLE antenna. The portable device control unit 31 is also mainly composed of a microcomputer having a processor and memory. The portable device control unit 31 controls transmission and reception by the portable device antenna 30 by the processor executing a program stored in the memory. The portable device control unit 31 is configured so that when the portable device antenna 30 receives radio waves transmitted from the in-vehicle antenna 10, the portable device control unit 31 transmits radio waves corresponding to the received radio waves from the portable device antenna 30.

[0015] 1 shows a state in which a user 2 has the portable device 3 in, for example, a back pocket of his / her trousers (in other words, a cleavage pocket or a hip pocket). Also, FIG. 1 shows a state in which a reflector 4 that reflects radio waves in a predetermined band (for example, the 2.4 GHz band) is located farther away from the user 2 as viewed from the vehicle 1. The reflector 4 is, for example, a building such as a wall.

[0016] Next, a description will be given of the control process executed by the control unit 20 included in the vehicle communication system of the first embodiment. In the following description, steps will be simply represented as "S".

[0017] As shown in the flowchart of FIG. 2, in S10, the control unit 20 starts this control process in a state where the vehicle 1 is stopped and all the doors of the vehicle 1 are closed. In S20, the control unit 20 determines whether or not a reflector 4 is present outside the vehicle 1, and if a reflector 4 is present, calculates the distance L between the vehicle 1 and the reflector 4. The processing of S20 will be described in detail with reference to Figs. 3 to 9.

[0018] 3, in S201, the control unit 20 executes transmission and reception using the multiple in-vehicle antennas 10. Next, in S202, the control unit 20 acquires IQ data of multiple channels of transmitted and received signals. Subsequently, the control unit 20 executes both the processes of S203 to S208 and the processes of S209 to S214.

[0019] First, the processes in S203 to S208 will be described. In S203, the control unit 20 generates a distribution diagram showing the relationship between distance measurement values ​​and frequency from the IQ data of the transmitted and received signals by the single on-board antenna 10. Note that Fig. 4 shows a state in which transmission and reception are performed by the single on-board antenna 10 when a reflector 4 is present outside the vehicle 1. Specifically, Fig. 4 shows a state in which a first antenna 11 of the multiple antennas transmits radio waves, and the radio waves are reflected by a reflector 4 present in front of the first antenna 11 and received again by the first antenna 11.

[0020] Fig. 5 is a distribution diagram showing the relationship between distance measurement values ​​and frequency, generated from the IQ data of signals transmitted and received by the first antenna 11. In the distribution diagram, the horizontal axis represents distance measurement values ​​and the vertical axis represents frequency. In Fig. 5, there is a frequently occurring peak value in the distance measurement values ​​of R2 (e.g., about 4 m). The relatively rarely occurring peak value in the distance measurement values ​​of R1 (e.g., about 1 m) is thought to be due to waves reflected off the ground. On the other hand, unlike Fig. 4, Fig. 6 is a distribution diagram generated from the IQ data of signals transmitted and received by the first antenna 11 when no reflector 4 is present in front of the first antenna 11. In Fig. 6, there is also a relatively frequent peak value in the distance measurement value of R3 (for example, 1 m), but this peak value is thought to be due to waves reflected off the ground.

[0021] In S204 of Fig. 3, the control unit 20 obtains the shortest distance measurement value from the distribution map, excluding the distance (e.g., about 1 m) between the vehicle-mounted antenna 10 and the ground. In Fig. 5, the shortest distance measurement value is R2 (e.g., about 4 m). On the other hand, in Fig. 6, if the distance between the vehicle-mounted antenna 10 and the ground is excluded, there is no shortest distance measurement value. Note that in Fig. 6, the distance measurement value R4 (e.g., about 2 m) occurs very rarely, so it does not affect the distance measurement and can be ignored as a reflector 4.

[0022] In S205, if the shortest measured distance value does not exist in the process of S204 (that is, S205: No), the process proceeds to S206, where it is determined that the reflector 4 does not exist. On the other hand, in S205, if the shortest distance measurement value exists in the processing of S204 (i.e., S205: Yes), the processing proceeds to S207, and it is determined that the reflector 4 exists in front of the vehicle-mounted antenna 10. Note that, when the vehicle-mounted antenna 10 is, for example, the first antenna 11, the front of the vehicle-mounted antenna 10 refers to the vehicle width direction relative to the first antenna 11.

[0023] Next, in S208, the control unit 20 calculates the distance L between the vehicle 1 and the reflector 4 using the shortest measured distance value using the following (Equation 1), and stores it in memory.

number

[0024] Next, the processes of S209 to S214 will be described. In S209, the control unit 20 generates a distribution diagram showing the relationship between distance measurement values ​​and frequency from the IQ data of signals transmitted and received by the multiple on-board antennas 10. Note that Fig. 7 shows a state in which transmission and reception are performed by the multiple on-board antennas 10. Specifically, Fig. 7 shows a state in which a first antenna 11 of the multiple antennas transmits a radio wave, and the second antenna 12 receives the reflected wave reflected by a reflector 4 located outside the vehicle 1 in an area between the first antenna 11 and the second antenna 12. Note that in Fig. 7, the distance AD ​​between the first antenna 11 and the second antenna 12 is, for example, 2.3 m.

[0025] Fig. 8 is a distribution diagram showing the relationship between distance measurement values ​​and frequency, generated from the IQ data of signals transmitted and received between multiple vehicle-mounted antennas 10. In Fig. 8, there is a frequently occurring peak value in the distance measurement values ​​of R6 (e.g., approximately 4.7 m). Note that the relatively infrequent peak value in the distance measurement values ​​of R5 (e.g., approximately 2.3 m) is thought to be due to radio waves that travel in a straight line between the first antenna 11 and the second antenna 12.

[0026] 9 is a distribution diagram generated from IQ data of signals transmitted and received between multiple on-board antennas 10 in a state where there is no reflector 4 present in the area between the first antenna 11 and the second antenna 12 outside the vehicle 1, unlike Fig. 7. In Fig. 9, there is also a relatively frequent peak value in the distance measurement value of R7 (for example, about 2.3 m), but this peak value is thought to be due to radio waves that have traveled in a straight line between the first antenna 11 and the second antenna 12.

[0027] In S210 of Fig. 3, the control unit 20 obtains the shortest measured distance value from the distribution map, excluding the distances between the multiple on-board antennas 10. In Fig. 8, the shortest measured distance value is R6 (e.g., approximately 4.7 m). On the other hand, in Fig. 9, the shortest measured distance value does not exist. Note that in Fig. 9, the measured distance value R8 (e.g., approximately 3 m) occurs very rarely, so it does not affect the distance measurement and can be ignored as a reflector 4.

[0028] In S211, if the shortest distance measurement value does not exist in the process of S210 (that is, S211: No), the process proceeds to S212, where it is determined that the reflector 4 does not exist. On the other hand, in S211, if the shortest distance measurement value exists in the processing of S210 above (i.e., S211: Yes), the processing proceeds to S213, and it is determined that a reflector 4 exists in the area between multiple vehicle antennas 10 outside the vehicle 1.

[0029] Next, in S214, the control unit 20 calculates the distance L between the vehicle 1 and the reflector 4 using the shortest measured distance value using the following (Equation 2), and stores it in memory.

number

[0030] The above is a detailed description of S20 in Fig. 2. Returning to Fig. 2 again, in S30, if the control unit 20 determines that no reflector 4 is present outside the vehicle 1 in the processing of S20 (i.e., S30: No), the processing proceeds to S40.

[0031] In S40, the control unit 20 acquires a plurality of distance measurements obtained by wireless communication between the plurality of in-vehicle antennas 10 and the portable device 3. For example, the control unit 20 acquires a distance measurement obtained by wireless communication between the first antenna 11 and the portable device 3, and a distance measurement obtained by wireless communication between the second antenna 12 and the portable device 3. In the following description, the distance measurement obtained by wireless communication between the first antenna 11 and the portable device 3 will be referred to as the "measured distance R1 between the first antenna and the portable device," and the distance measurement obtained by wireless communication between the second antenna 12 and the portable device 3 will be referred to as the "measured distance R2 between the second antenna and the portable device."

[0032] Next, in S50, the control unit 20 calculates the position of the portable device 3 from the multiple distance measurements acquired in S40. Fig. 10 is an explanatory diagram for explaining the calculation method in S50. In Fig. 10, the solid line R1 is the "measured distance R1 between the first antenna and the portable device," and the solid line R2 is the "measured distance R2 between the second antenna and the portable device." The control unit 20 can calculate the position of the portable device 3 from the coordinate P of the intersection of the solid lines R1 and R2.

[0033] Next, in S60, the control unit 20 cooperates with the vehicle ECU to perform vehicle control such as unlocking, locking or welcome control of the vehicle 1 according to the position of the portable device 3. ECU is an abbreviation for Electronic Control Unit.

[0034] On the other hand, in the above S30, if the control unit 20 determines in the process of S20 that a reflector 4 is present outside the vehicle 1 (that is, S30: Yes), the process proceeds to S70.

[0035] In S70, similar to S40, the control unit 20 acquires a plurality of distance measurements obtained by wireless communication between the plurality of in-vehicle antennas 10 and the portable device 3. Subsequently, in S80, similar to S50, the control unit 20 calculates the position of the portable device 3 from the plurality of distance measurements acquired in S70.

[0036] Next, in S90, the control unit 20 recalculates the distance measurement value according to the position of the portable device 3 calculated in S80. Then, in S100, the correct position of the portable device 3 is calculated, and in S110, vehicle control is executed according to the position of the portable device 3. The processing of S90 to S110 will be described in detail with reference to Figs. 11 to 16.

[0037] As shown in the flowchart of FIG. 11 , in S901 following S80, the control unit 20 determines whether the position of the portable device 3 calculated in S80 is farther from the reflector 4 as seen from the vehicle 1. Here, FIG. 12 shows an example of the position of the portable device 3 calculated in S80. In FIG. 12 , the symbol M indicates the position of the portable device 3 calculated in S80, and the symbol N indicates the actual position of the portable device 3. As shown in FIG. 12 , if at least one of the "measured distance R1 between the first antenna and the portable device" and the "measured distance R2 between the second antenna and the portable device" is a distance measured using a wave reflected by the reflector 4, the position of the portable device 3 calculated using the measured distance may be farther from the reflector 4 as seen from the vehicle 1. If the position of the portable device 3 calculated in S80 is farther from the reflector 4 as seen from the vehicle 1, the position of the portable device 3 is considered to be an incorrect position. On the other hand, if the position of the portable device 3 calculated in S80 is closer to the vehicle 1 than the reflector 4, the position of the portable device 3 is considered to be the correct position.

[0038] In S901, if the position of the portable device 3 calculated in S80 is closer than the reflector 4 as viewed from the vehicle 1 (i.e., S901: Yes), the control unit 20 proceeds to S902. In S902, the control unit 20 determines that the position of the portable device 3 calculated in S80 is the correct position, and proceeds to S110. In S110, the control unit 20 cooperates with the vehicle ECU to execute vehicle control according to the position of the portable device 3.

[0039] On the other hand, in S901, if the position of the portable device 3 calculated in S80 is farther from the vehicle 1 than the reflector 4 (i.e., S901: No), the control unit 20 proceeds to S903. In the following S903 to S905, the control unit 20 recalculates the distance measurement value to calculate a corrected distance measurement value, and calculates the correct position of the portable device 3.

[0040] First, in S903, the control unit 20 assumes that the "measured distance R1 between the first antenna and the portable device" is measured using a wave reflected by the reflector 4, and calculates a corrected measured distance value by correcting the measured distance value based on this assumption. This corrected measured distance value is calculated using the following (Equation 3).

[0041]

number

[0042] From the above (Equation 3), the corrected distance measurement value is obtained as a function of x and y. Note that the above (Equation 3) is derived from Pythagoras' theorem regarding the right triangle formed by the coordinates (0, 2L), (x, y), and (0, y), when the coordinates of the first antenna 11 are (0, 0), the coordinates of the virtual wave source are (0, 2L), and the coordinates of the portable device 3 are (x, y), as shown in FIG. 13.

[0043] In the following explanation, the corrected distance measurement value obtained by correcting the "measured distance value R1 between the first antenna and the portable device" using the above (Equation 3) will be referred to as the "corrected distance measurement value RC1 between the first antenna and the portable device." Also, the corrected distance measurement value obtained by correcting the "measured distance value R2 between the second antenna and the portable device" using the above (Equation 3) will be referred to as the "corrected distance measurement value RC2 between the second antenna and the portable device."

[0044] As shown in Fig. 14, the control unit 20 calculates the position of the portable device 3 using the "corrected distance measurement value RC1 between the first antenna and the portable device" and the "distance measurement value R2 between the second antenna and the portable device." In Fig. 14, the solid line RC1 is the "corrected distance measurement value RC1 between the first antenna and the portable device," and the solid line R2 is the "distance measurement value R2 between the second antenna and the portable device." The control unit 20 can calculate the position of the portable device 3 from the coordinates of the intersection of the solid line RC1 and the solid line R2. The position of the portable device 3 calculated using this method is referred to as the first position P1.

[0045] Next, in S904 of FIG. 11, the control unit 20 assumes that the "measured distance R2 between the second antenna and the portable device" is measured using a wave reflected by the reflector 4, and calculates a corrected measured distance based on this assumption. As shown in FIG. 15, the control unit 20 calculates the position of the portable device 3 using the "corrected measured distance RC2 between the second antenna and the portable device" and the "measured distance R1 between the first antenna and the portable device." Note that in FIG. 15, the solid line RC2 is the "corrected measured distance RC2 between the second antenna and the portable device," and the solid line R1 is the "measured distance R1 between the first antenna and the portable device." The control unit 20 can calculate the position of the portable device 3 from the coordinates of the intersection of the solid lines R1 and RC2. The position of the portable device 3 calculated using this method is referred to as the second position P2.

[0046] Next, in S905 of FIG. 11, the control unit 20 assumes that the "measured distance R1 between the first antenna and the portable device" is measured using a wave reflected by the reflector 4, and calculates a corrected measured distance based on this assumption. Also, the control unit 20 assumes that the "measured distance R2 between the second antenna and the portable device" is measured using a wave reflected by the reflector 4, and calculates a corrected measured distance based on this assumption. Next, as shown in FIG. 16, the control unit 20 calculates the position of the portable device 3 using the "corrected measured distance RC1 between the first antenna and the portable device" and the "corrected measured distance RC2 between the second antenna and the portable device." In FIG. 16, the solid line RC1 represents the "corrected measured distance RC1 between the first antenna and the portable device," and the solid line RC2 represents the "corrected measured distance RC2 between the second antenna and the portable device." The control unit 20 can calculate the position of the portable device 3 from the coordinates of the intersection of the solid lines RC1 and RC2. The position of the portable device 3 calculated using this method is designated as the third position P3.

[0047] 11, the control unit 20 determines at least one of the first position P1, the second position P2, and the third position P3, or an average value thereof, as the correct position of the portable device 3. For example, the control unit 20 may determine that the one of the first position P1, the second position P2, and the third position P3 that is closest to the vehicle 1 is the correct position of the portable device 3. Alternatively, when the first position P1, the second position P2, and the third position P3 are viewed over time, the control unit 20 may determine that the one whose movement path is continuous is the correct position of the portable device 3. Finally, in S110, the control unit 20 cooperates with the vehicle ECU to execute vehicle control according to the position of the portable device 3.

[0048] The vehicle communication system of the first embodiment described above provides the following advantages. (1) The control unit 20 included in the vehicle communication system of the first embodiment determines whether or not there is a reflector 4 that reflects radio waves in a predetermined band outside the vehicle 1. If there is no reflector 4 outside the vehicle 1, the control unit 20 calculates the position of the portable device 3 using a plurality of distance measurements obtained by wireless communication between the plurality of on-board antennas 10 and the portable device 3. On the other hand, if there is a reflector 4 outside the vehicle 1, the control unit 20 calculates the distance L between the vehicle 1 and the reflector 4, and calculates the position of the portable device 3 using the distance L between the vehicle 1 and the reflector 4 and the plurality of distance measurements obtained by wireless communication between the plurality of on-board antennas 10 and the portable device 3. According to this, the control unit 20 can determine whether or not a reflector 4 exists outside the vehicle 1, thereby enabling the control unit 20 to calculate the position of the portable device 3 with high accuracy both when a reflector 4 does not exist and when a reflector 4 exists. Furthermore, when a reflector 4 exists outside the vehicle 1, the control unit 20 can calculate the position of the portable device 3 with high accuracy by using the distance measurement value obtained by wireless communication between the in-vehicle antenna 10 and the portable device 3 and the distance L between the vehicle 1 and the reflector 4, even if the distance measurement value is due to a wave reflected by the reflector 4. Therefore, this vehicular communication system can perform vehicle control according to the accurate position of the portable device 3.

[0049] (2) In the vehicle communication system of the first embodiment, the multiple on-board antennas 10 each perform distance measurement by independent transmission and reception, and acquire multiple distance measurement values ​​calculated from multiple IQ data of multiple channels in the transmitted and received signals. The control unit 20 then excludes the distance between the on-board antennas 10 and the ground from the multiple distance measurement values, determines whether a reflector 4 is present, and calculates the distance L between the vehicle 1 and the reflector 4 if a reflector 4 is present. This vehicle communication system also measures distances by transmitting and receiving signals between the multiple on-board antennas 10, and acquires multiple distance measurement values ​​calculated from multiple IQ data of multiple channels in the transmitted and received signals. The control unit 20 then excludes the distances between the multiple on-board antennas 10 from the multiple distance measurement values, determines whether or not a reflector 4 exists outside the vehicle 1, and calculates the distance L between the vehicle 1 and the reflector 4 if a reflector 4 exists. According to this, the vehicle communication system can calculate whether or not a reflector 4 exists in front of each vehicle-mounted antenna 10 and the distance between the reflector 4 and the vehicle 1 by having each of the vehicle-mounted antennas 10 measure distances by transmitting and receiving signals independently from each other. Also, the vehicle communication system can calculate whether or not a reflector 4 exists in the area between the vehicle-mounted antennas 10 and the distance between the reflector 4 and the vehicle 1 by having each of the vehicle-mounted antennas 10 measure distances by transmitting and receiving signals between each other.

[0050] (3) The vehicle communication system of the first embodiment calculates the distance L between the vehicle 1 and the reflector 4 when the vehicle 1 is stopped and all doors of the vehicle 1 are closed. At this time, when the multiple on-board antennas 10 each perform distance measurement by transmitting and receiving independently, the control unit 20 calculates the distance L between the vehicle 1 and the reflector 4 using the above (Equation 1). Also, when the multiple on-board antennas 10 perform distance measurement by transmitting and receiving between each other, the control unit 20 calculates the distance L between the vehicle 1 and the reflector 4 using the above (Equation 2). This allows the control unit 20 to easily calculate the distance between the vehicle 1 and a reflector 4 located in front of each vehicle-mounted antenna 10 using the above (Equation 1). Also, the control unit 20 can easily calculate the distance between the vehicle 1 and a reflector 4 located between multiple vehicle-mounted antennas 10 using the above (Equation 2). Therefore, the calculation load on the control unit 20 can be reduced.

[0051] (4) In the first embodiment, when the position of the portable device 3 calculated using a plurality of distance measurement values ​​obtained by measuring the distances between the plurality of in-vehicle antennas 10 and the portable device 3 is closer than the reflector 4 as viewed from the vehicle 1, the control unit 20 determines that the position of the portable device 3 is correct and controls the vehicle 1. On the other hand, when the position of the portable device 3 calculated using a plurality of distance measurement values ​​obtained by measuring the distances between the plurality of in-vehicle antennas 10 and the portable device 3 is farther than the reflector 4 as viewed from the vehicle 1, the control unit 20 recalculates the position using the following methods (A), (B), and (C). (A) The position of the portable device 3 is recalculated using the "corrected distance measurement value RC1 between the first antenna and the portable device" and the "distance measurement value R2 between the second antenna and the portable device." The position of the portable device 3 calculated using this method is designated as the first position P1. (B) The position of the portable device 3 is recalculated using the "measured distance R1 between the first antenna and the portable device" and the "corrected measured distance RC2 between the second antenna and the portable device." The position of the portable device 3 calculated using this method is designated as the second position P2. (C) The position of the portable device 3 is recalculated using the "corrected distance measurement value RC1 between the first antenna and the portable device" and the "corrected distance measurement value RC2 between the second antenna and the portable device." The position of the portable device 3 calculated using this method is designated as the third position P3. The control unit 20 then determines at least one of the first position P1, the second position P2, and the third position P3, or the average value thereof, as the correct position of the portable device 3, and controls the vehicle 1. According to this, when a reflector 4 is present outside the vehicle 1, the control unit 20 can calculate the position of the portable device 3 with high accuracy even if one or both of the multiple distance measurements taken between the multiple on-board antennas 10 and the portable device 3 are measured using reflected waves reflected by the reflector 4. Furthermore, the control unit 20 can calculate the position of the portable device 3 with high accuracy even if both of the multiple distance measurements taken between the multiple on-board antennas 10 and the portable device 3 are measured using direct waves not reflected by the reflector 4.

[0052] (5) In the first embodiment, when a reflector 4 is present outside the vehicle 1, the control unit 20 calculates a corrected distance measurement value using the above (Equation 3) assuming that the distance measurement value measured by wireless communication between the vehicle antenna 10 and the portable device 3 is measured using a reflected wave reflected by the reflector 4. This allows the control unit 20 to easily calculate the corrected distance measurement value using the above (Equation 3). The above (Equation 3) is a simple formula due to the use of a virtual wave source. Therefore, the calculation load on the control unit 20 can be reduced.

[0053] (Second embodiment) The second embodiment will be described. The second embodiment is different from the first embodiment in that the method of determining whether or not a reflector 4 is present and the method of calculating the distance between the reflector 4 and the vehicle 1 are changed, but the rest is the same as the first embodiment, so only the parts that are different from the first embodiment will be described.

[0054] 17, in the second embodiment, a vehicle 1 is equipped with a plurality of sonar sensors 5. Using information obtained from the plurality of sonar sensors 5, a control unit 20 of the vehicle communication system can determine whether a reflector 4 is present outside the vehicle 1, and can calculate a distance L between the vehicle 1 and the reflector 4 if a reflector 4 is present outside the vehicle 1.

[0055] In the second embodiment described above, when the vehicle 1 is equipped with multiple sonar sensors 5, the control unit 20 can use information obtained from the multiple sonar sensors 5 to determine whether a reflector 4 is present outside the vehicle 1 and calculate the distance L between the vehicle 1 and the reflector 4.

[0056] (Other embodiments) (1) In each of the above embodiments, the vehicle communication system has been described as having four vehicle antennas 10 mounted on the front, rear, left and right sides of the vehicle 1, but this is not limited to this. For example, the number and mounting positions of the vehicle antennas 10 can be set arbitrarily.

[0057] (2) In the above embodiments, the vehicular communication system has been described as detecting the position of the portable device 3 using two on-board antennas 10 mounted on the right side of the vehicle 1, but this is not limited thereto. For example, the vehicular communication system may detect the position of the portable device 3 using an on-board antenna 10 mounted on the front, left, or rear side of the vehicle 1, or may detect the position of the portable device 3 using three or more on-board antennas 10.

[0058] (3) In each of the above embodiments, a BLE antenna has been described as the in-vehicle antenna 10. However, this is not limited to this, and various types of wireless communication antennas, such as UWB (Ultra Wide Band) or RFID (Radio Frequency Identification), may also be used.

[0059] (4) If there is a reflector 4 such as a pole, street light, or utility pole outside the vehicle 1, the vehicle communication system may analyze the image captured by the on-board camera and exclude the reflector 4 from the determination.

[0060] (5) In each of the above embodiments, the position of the portable device 3 is calculated by the vehicle-side control unit 20. However, this is not limited to this. For example, the portable device-side control unit 31 may calculate the position of the portable device 3 from distance measurements obtained through wireless communication between the multiple vehicle-mounted antennas 10 and the portable device 3, and transmit the result to the vehicle-side control unit 20.

[0061] (5) In the above embodiments, the control unit 20 calculates the corrected distance measurement value using the above (Equation 3), but this is not limited to this. For example, the control unit 20 may calculate the corrected distance measurement value using the following simultaneous equations (Equation 4) and (Equation 5).

number

number

[0062] The present disclosure is not limited to the above-described embodiments and can be modified as appropriate within the scope of the claims. Furthermore, the above-described embodiments and portions thereof are not unrelated to each other and can be combined as appropriate unless the combination is clearly impossible. It goes without saying that, in each of the above embodiments, the elements constituting the embodiments are not necessarily essential unless specifically stated as essential or clearly considered essential in principle. Furthermore, in each of the above embodiments, when numerical values ​​such as the number, values, amounts, and ranges of components of the embodiments are mentioned, they are not limited to the specific numbers unless specifically stated as essential or clearly limited to a specific number in principle. Furthermore, in each of the above embodiments, when the shape, positional relationship, etc. of components are mentioned, they are not limited to the shape, positional relationship, etc., unless specifically stated or limited to a specific shape, positional relationship, etc. in principle.

[0063] The control unit 20 and the methods described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit 20 and the methods described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit 20 and the methods described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium. The memory described above is a non-transitory tangible storage medium. [Explanation of symbols]

[0064] 1 vehicle 2 users 3. Portable devices 4 reflector 10 Vehicle antenna 20 Control Unit

Claims

1. In a vehicle communication system that wirelessly communicates with a portable device (3) carried by a user (2) of a vehicle (1), detects the location of the portable device, and controls the vehicle, Multiple on-board antennas (10) mounted on the vehicle, which transmit and receive radio waves in a predetermined frequency band, The system includes a control unit (20) that controls transmission and reception by multiple vehicle-mounted antennas, The control unit, It is determined whether or not a reflector (4) that reflects radio waves in the predetermined frequency band exists outside the vehicle. If the reflector is not present outside the vehicle, the position of the portable device is calculated using multiple distance values ​​measured by wireless communication between multiple vehicle-mounted antennas and the portable device. If the reflector is located outside the vehicle, the distance (L) between the vehicle and the reflector is calculated, and the position of the portable device is calculated using the multiple distance values ​​measured by wireless communication between the multiple vehicle-mounted antennas and the portable device, and the distance between the vehicle and the reflector. The control unit, From the multiple distance values ​​calculated from multiple IQ data of multiple channels in the transmitted and received signals obtained by each of the multiple vehicle-mounted antennas individually, the distance between the vehicle-mounted antenna and the ground, which has been determined in advance, is excluded, and it is determined whether or not the reflector exists outside the vehicle, and if the reflector exists, the distance between the vehicle and the reflector is calculated, A vehicle communication system that excludes the distance between multiple vehicle antennas, which has been previously determined, from multiple distance measurement values ​​calculated from multiple IQ data of multiple channels in the transmitted and received signals obtained by transmitting and receiving between multiple vehicle antennas, determines whether or not the reflector exists outside the vehicle, and calculates the distance between the vehicle and the reflector if the reflector exists.

2. The control unit calculates the distance between the vehicle and the reflector when the vehicle is stopped and all of the vehicle's doors are closed. When multiple vehicle-mounted antennas perform distance measurement by transmitting and receiving independently, the distance between the vehicle and the reflector is calculated using the following equation (Equation 1). The vehicle communication system according to claim 1, wherein when distance measurement is performed by transmission and reception between multiple vehicle-mounted antennas, the distance between the vehicle and the reflector is calculated using the following (Equation 2). [Math 1] [Math 2] However, L is the distance between the vehicle and the reflector.

3. A vehicle communication system that performs wireless communication with a portable device (3) carried by a user (2) of a vehicle (1), detects the location of the portable device, and controls the vehicle, Multiple on-board antennas (10) mounted on the vehicle, which transmit and receive radio waves in a predetermined frequency band, The system includes a control unit (20) that controls transmission and reception by multiple vehicle-mounted antennas, The control unit, It is determined whether or not a reflector (4) that reflects radio waves in the predetermined frequency band exists outside the vehicle. If the reflector is not present outside the vehicle, the position of the portable device is calculated using multiple distance values ​​measured by wireless communication between multiple vehicle-mounted antennas and the portable device. If the reflector is located outside the vehicle, the distance (L) between the vehicle and the reflector is calculated, and the position of the portable device is calculated using the multiple distance values ​​measured by wireless communication between the multiple vehicle-mounted antennas and the portable device, and the distance between the vehicle and the reflector. The control unit, when the reflector is located outside the vehicle, If the position of the portable device, calculated using multiple distance measurement values ​​obtained between multiple vehicle-mounted antennas and the portable device, is closer to the reflector from the perspective of the vehicle, then the calculated position of the portable device is determined to be the correct position, and the vehicle is controlled accordingly. A vehicle communication system that, when the position of the portable device calculated using multiple distance measurement values ​​obtained between multiple vehicle-mounted antennas and the portable device is farther from the vehicle than the reflector, determines at least one or the average value of the first position (P1), second position (P2), and third position (P3) of the portable device, recalculated by the following methods (A), (B), and (C), as the correct position of the portable device and controls the vehicle. (A) The position of the portable device calculated using "a corrected distance value obtained by assuming that the distance measured by wireless communication between a predetermined onboard antenna and the portable device was measured using radio waves reflected by the reflector" and "a distance value obtained by assuming that the distance measured by wireless communication between another onboard antenna and the portable device was measured using radio waves not reflected by the reflector" is defined as the first position. (B) The position of the portable device calculated using "a distance measurement value obtained by wireless communication between a predetermined onboard antenna and the portable device, assuming that the distance was measured using radio waves not reflected by the reflector" and "a corrected distance measurement value obtained by correcting a distance measurement value obtained by wireless communication between another onboard antenna and the portable device, assuming that the distance was measured using radio waves reflected by the reflector" is defined as the second position. (C) The position of the portable device calculated using "a corrected distance value obtained by assuming that the distance measured by wireless communication between a predetermined onboard antenna and the portable device among the multiple onboard antennas was measured using radio waves reflected by the reflector" and "a corrected distance value obtained by assuming that the distance measured by wireless communication between another onboard antenna and the portable device among the multiple onboard antennas was measured using radio waves reflected by the reflector" is the third position.

4. The vehicle communication system according to claim 3, wherein, when the reflector is present outside the vehicle, the control unit calculates a corrected distance value using the following (Equation 3) when it assumes that the distance measured by wireless communication between the vehicle antenna and the portable device was measured by radio waves reflected by the reflector. [Math 3] However, R is the distance measured by wireless communication between the vehicle-mounted antenna and the portable device. x and y are the coordinates of the portable device, i.e., the corrected distance measurement values. L is the distance between the vehicle and the reflector.

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