JP7231399B2 - Occupant detection system and occupant detection method - Google Patents

Description

The present invention relates to an occupant detection system and an occupant detection method that enable detection of the presence or absence of an occupant at each seat in a vehicle without using a dedicated camera or sensor.

In order to ensure safety and utilize big data in self-driving cars and connected cars, it is necessary to ascertain whether or not each seat is occupied. However, equipping a vehicle with a dedicated camera or sensor for confirming the presence or absence of a passenger in each seat leads to an increase in manufacturing costs of the vehicle.

For example, in Patent Literature 1, a radio wave transmitting unit and a radio wave receiving unit are provided in a vehicle so as to sandwich an occupant. It detects the presence or absence of an occupant.

In addition, in Non-Patent Document 1, when the transmission position is the instrument panel and the reception position is the right rear door switch panel (see FIG. 11) so as to sandwich the driver, the fluctuation of the propagation gain is UWB (Ultra Wide Band: It is shown that it is several dB in ultra-wideband communication and about 10 dB in narrowband communication (see FIG. 12).

JP 2018-004369 A

Kensuke Matsui, 3 others, "Measurement of fluctuations in UWB radio wave propagation characteristics in vehicle cabins", The Institute of Electronics, Information and Communication Engineers General Conference, Proceedings No. B-1-2, 2018

However, according to the above-mentioned Patent Document 1, it is possible to detect occupants using narrowband radio, but as can be seen from FIG. In automobiles, the reception strength of narrowband radio tends to be unstable due to fading. Therefore, the difference between the received power when the driver is not on board and when the driver is on board may become so small that it cannot be distinguished, and the occupant detection may not be performed reliably.
Accordingly, an object of the present invention is to provide means for solving such problems.

In order to solve the above problems, the present invention employs the following configuration.
That is, the invention according to claim 1 is
An occupant detection system in a communication system that performs in-vehicle communication using UWB (Ultra Wide Band) radio,
a wireless terminal that transmits a wireless signal of UWB wireless;
at least one other wireless terminal that receives the wireless signal transmitted from the wireless terminal;
The at least one other radio terminal is characterized by determining that there is an occupant in the vehicle when the received power value of the radio signal is equal to or less than a predetermined reference power value.

According to the above configuration, since the UWB in-vehicle wireless communication system provided in a vehicle such as an automobile is used without using a dedicated device or sensor, it is possible to detect the occupant of each seat without increasing the manufacturing cost of the automobile. becomes possible. In addition, since UWB radio is used instead of narrow band radio, it is possible to stably determine the presence or absence of a passenger.

In order to solve the above problems, the invention according to claim 2 is an occupant detection system in a communication system that performs in-vehicle communication using UWB (Ultra Wide Band) radio,
a wireless terminal that receives a wireless signal of UWB wireless;
at least one other wireless terminal that transmits said wireless signal to said wireless terminal;
The radio terminal is characterized by determining that there is a passenger in the vehicle when the received power value of the radio signal is equal to or less than a predetermined reference power value.

According to the above configuration, since the UWB in-vehicle wireless communication system provided in a vehicle such as an automobile is used without using a dedicated device or sensor, it is possible to detect the occupant of each seat without increasing the manufacturing cost of the automobile. becomes possible. In addition, since UWB radio is used instead of narrow band radio, it is possible to stably determine the presence or absence of a passenger.

In order to solve the above problem, the invention according to claim 3 is the occupant detection system according to claim 1 or 2, wherein the wireless terminal and the at least one other wireless terminal, when the passenger is present, It is characterized in that it is arranged at a position where communication is performed not by line-of-sight waves of the radio signal but by diffracted waves and reflected waves by the occupant and the vehicle.

According to the above configuration, it is possible to detect an occupant by utilizing the fact that the received power of UWB varies stably depending on the presence or absence of an occupant.

In order to solve the above problems, the invention according to claim 4 provides the occupant detection system according to claim 1 or 3, when there are a plurality of the other wireless terminals,
The wireless terminal receives determination results regarding the presence or absence of occupants in the vehicle from each of the plurality of other wireless terminals, and based on the determination results regarding the presence or absence of occupants in the vehicle from each of the plurality of other wireless terminals, It is characterized by judging whether or not there is an occupant in the vehicle.

According to the above configuration, it is determined whether or not there is a passenger in the vehicle by using the determination results regarding the presence or absence of a passenger from a plurality of wireless terminals, so it is possible to improve the accuracy of the determination regarding the presence or absence of a passenger.

In order to solve the above problems, the invention according to claim 5 provides the occupant detection system according to claim 2 or 3, when there are a plurality of the other wireless terminals,
The radio terminal receives the radio signal from each of the plurality of other radio terminals, and determines that there is an occupant in the vehicle when each received power value is equal to or less than a predetermined reference power value. It is characterized by

According to the above configuration, the radio terminal can perform normal communication between the radio terminal and the other radio terminals without receiving the determination result regarding the presence or absence of a passenger from each of the other radio terminals. The terminal will be able to determine whether there is an occupant in the vehicle.

In order to solve the above problems, the invention according to claim 6 provides the occupant detection system according to claim 1 or 3, when there are a plurality of the other wireless terminals,
A collection terminal that receives determination results regarding the presence or absence of occupants in the vehicle from each of the plurality of other wireless terminals, and transmits determination results regarding the presence or absence of occupants in the vehicle from each of the plurality of other wireless terminals to an application system. characterized by comprising

According to the above configuration, since the collection terminal is arranged instead of the wireless terminal at the point of contact with the application system, the determination result regarding the presence or absence of passengers in the vehicle is transmitted to the application system regardless of the occurrence of the communication event. becomes possible. In addition, it becomes possible to transmit the determination result regarding the presence or absence of passengers in the vehicle to the collection terminal at a timing when the in-vehicle wireless communication system is not overloaded.

In order to solve the above problems, the invention according to claim 7 provides the occupant detection system according to claim 2 or 3, when there are a plurality of the other wireless terminals,
It is characterized by including a collection terminal that receives a determination result regarding the presence or absence of a passenger in the vehicle from the wireless terminal and transmits the determination result regarding the presence or absence of a passenger in the vehicle from the wireless terminal to an application system.

According to the above configuration, since the collection terminal is arranged instead of the wireless terminal at the point of contact with the application system, the determination result regarding the presence or absence of passengers in the vehicle is transmitted to the application system regardless of the occurrence of the communication event. becomes possible. In addition, it becomes possible to transmit the determination result regarding the presence or absence of passengers in the vehicle to the collection terminal at a timing when the in-vehicle wireless communication system is not overloaded.

In order to solve the above problems, the invention according to claim 8 is an occupant detection method in a communication method for performing in-vehicle communication using UWB (Ultra Wide Band) radio,
a wireless terminal transmitting a radio signal for UWB radio;
at least one other wireless terminal receiving said wireless signal transmitted from said wireless terminal;
The at least one other radio terminal is characterized by determining that there is an occupant in the vehicle when the received power value of the radio signal is equal to or less than a predetermined reference power value.

According to the above configuration, since the UWB in-vehicle wireless communication system provided in a vehicle such as an automobile is used without using a dedicated device or sensor, it is possible to detect the occupant of each seat without increasing the manufacturing cost of the automobile. becomes possible. In addition, since UWB radio is used instead of narrow band radio, it is possible to stably determine the presence or absence of a passenger.

In order to solve the above problems, the invention according to claim 9 is an occupant detection method in a communication method for performing in-vehicle communication using UWB (Ultra Wide Band) radio,
a wireless terminal receiving a radio signal of a UWB radio;
at least one other wireless terminal transmitting said wireless signal to said wireless terminal;
The radio terminal is characterized by determining that there is a passenger in the vehicle when the received power value of the radio signal is equal to or less than a predetermined reference power value.

According to the above configuration, since the UWB in-vehicle wireless communication system provided in a vehicle such as an automobile is used without using a dedicated device or sensor, it is possible to detect the occupant of each seat without increasing the manufacturing cost of the automobile. becomes possible. In addition, since UWB radio is used instead of narrow band radio, it is possible to stably determine the presence or absence of a passenger.

According to the present invention, a UWB in-vehicle wireless communication system installed in a vehicle such as an automobile is used without using a dedicated device or sensor, so that an occupant can be detected at each seat without increasing the manufacturing cost of the automobile. becomes possible. In addition, since UWB radio is used instead of narrow band radio, it is possible to stably determine the presence or absence of a passenger.

FIG. 3 is a block diagram showing an example of arrangement of radio terminals in a vehicle using UWB radio; 3 is a schematic diagram showing variations in received power of UWB radio and single frequency radio between radio terminal 100 and radio terminal 200. FIG. 4 is a schematic diagram showing variations in received power of UWB radio and single-frequency radio between radio terminal 100 and radio terminal 400. FIG. 1 is a block diagram showing an example of the configuration of a radio terminal 100; FIG. 4 is an example of a flow chart for determining presence/absence of a driver at wireless terminal 200 and wireless terminal 400. FIG. 4 is an example of a flow chart for determining presence/absence of a driver at wireless terminal 200 and wireless terminal 400. FIG. 6 is an example of a flow chart for determining presence/absence of a driver in the wireless terminal 100. FIG. It is an example of a flow chart when the presence or absence of a driver is determined by the wireless terminal 200 and the wireless terminal 400 and the collection terminal 600 is present. It is an example of a flow chart when the presence or absence of a driver is determined by the wireless terminal 200 and the wireless terminal 400 and the collection terminal 600 is present. It is an example of a flow chart when the wireless terminal 100 determines the presence or absence of a driver and the collection terminal 600 is present. 6 is a block diagram showing an example of the configuration of a collection terminal 600; FIG. It is a figure which shows an example of a prior art. It is a figure which shows an example of a prior art. It is a figure which shows an example of a prior art.

(Overview of UWB radio)
First, UWB will be described. UWB is ultra-wideband radio, as opposed to narrowband radio such as wireless LAN and Bluetooth (registered trademark). According to the definition of the Federal Communications Commission (FCC), UWB refers to radio frequencies with a fractional bandwidth of 20% or more or a bandwidth of 500 MHz or more. The fractional bandwidth η is given by Equation (1) below.

When radio waves are actually radiated into space, a wireless communication network based on UWB is operated under the radio wave law.

For example, in the United States, the FCC has approved the use of UWB for the frequency band of 3.1 to 10.6 GHz. Furthermore, the effective isotropically radiated power (EIRP) must be -41.25 dBm/MHz or less in that frequency range. In Europe, the European Telecommunications Standards Institute (ETSI) has approved the use of 3.1 to 4.8 GHz and 6.0 to 9.0 GHz. Furthermore, the EIRP should be -41.25 dBm/MHz or less in that frequency range. In Japan, the emission of radio waves is regulated by the Radio Law, but the specific specifications of usable UWB radio are stipulated by the standards of the Association of Radio Industries and Businesses (ARIB). . According to it, the use of UWB radio in 3.4-4.8 GHz and 7.25-10.25 GHz is permitted in Japan. Furthermore, the EIRP should be -41.25 dBm/MHz or less in that frequency range.

In the embodiments of the present invention, UWB is not limited to UWB radio within the frequency range defined by laws and regulations of each country. The UWB according to the embodiment of the present invention targets ultra-wideband radio as opposed to narrowband radio such as wireless LAN and Bluetooth, and radio frequency with a bandwidth corresponding to it. More specifically, UWB is a radio frequency that enables direct or reflected wave communication between devices in a metal conductor housing such as a car.

When wireless LAN, Bluetooth, or other narrow-band wireless communication is used for in-vehicle wireless communication, the interference phenomenon of multiple reflected waves caused by the body of the vehicle, which is a metal conductor, can cause a significant drop in radio wave intensity. If the wireless terminal is installed in a place where the radio wave intensity drops significantly, the communication quality may deteriorate or wireless communication may become impossible.

Therefore, UWB radio, which contains an extremely wide range of radio frequency components, has little spatial variation in radio wave intensity due to the frequency diversity effect of the extremely wide radio frequency component, and is less likely to experience a significant drop in radio wave intensity, can be used for in-vehicle wireless communication. Apply.

(Overview of wireless communication system)
In the present embodiment, when UWB wireless communication using radio frequencies of an extremely wide band is applied to in-vehicle communication that is not related to human body recognition in a car, the UWB untrained communication system is used to It has a configuration for determining the presence or absence of. Specifically, it is configured to determine whether or not there is an occupant in each seat based on changes in the propagation gain of radio waves in communication between UWB wireless terminals installed at various locations in the vehicle.

(Example of wireless terminal installation position)
FIG. 1 shows an example of wireless terminal positions by UWB radio. In the diagram of the vehicle in FIG. 1, the roof and pillars are omitted, and FIG. 1 is a perspective view of the vehicle from above. A passenger compartment (cabin) is surrounded by metal conductor bodies such as a firewall 30, doors (60, 70, 80, 90), a roof (not shown), a trunk 50 and a floor. Therefore, the vehicle interior is an environment of multiple reflection of radio waves.

In this embodiment, as shown in FIG. 1, the wireless terminal 100 is arranged at the center of the instrument panel, the wireless terminal 200 is arranged at the foot of the driver's seat, and the wireless terminal 300 is arranged at the foot of the front passenger seat. Further, the wireless terminal 400 is arranged on the switch panel of the right rear seat door 70 and the wireless terminal 500 is arranged on the switch panel of the left rear seat door 90 .

Wireless terminal 100 and wireless terminal 200, wireless terminal 100 and wireless terminal 300, wireless terminal 100 and wireless terminal 400, and wireless terminal 100 and wireless terminal 500 communicate simultaneously or when the need for communication arises.

The wireless terminals 100 and 200, and the wireless terminals 100 and 300 are shielded from the line of sight of the radio waves by the instrument panel and the center console 40 that protrude into the vehicle interior. It is possible to carry out wireless communication by means of waves.

Since the line of sight between the wireless terminal 100 and the wireless terminal 400 is blocked when the driver is seated in the driver's seat, communication is possible using waves diffracted by the human body and waves reflected by the vehicle body. In addition, wireless terminal 100 and wireless terminal 400 can communicate wirelessly using line-of-sight waves and reflected waves because line-of-sight is ensured when the driver is absent.

Similarly, since the radio terminal 100 and the radio terminal 500 have their line of sight blocked when an occupant is seated in the front passenger seat, communication is possible using waves diffracted by the human body and waves reflected by the vehicle body. In addition, radio terminal 100 and radio terminal 500 have line-of-sight when there is no passenger in the front passenger seat, so radio communication using line-of-sight waves and reflected waves is possible.

Since the inside of the vehicle is an environment of multiple reflected waves of radio waves, it is preferable that the gain of the antenna of each wireless terminal is wide directivity or omnidirectional in order to efficiently receive the radio waves. However, in the present embodiment, even if the antenna of each wireless terminal is a directional antenna, the effect of the present embodiment can be obtained, so it does not matter whether the antenna is omnidirectional.

(Variation of received power of radio waves at each wireless terminal position)
FIG. 2 shows the reception power at UWB (7.25 to 10.25 GHz) and single frequency (8.75 GHz CW) when wireless terminal 100 is the transmitting terminal and wireless terminal 200 at the foot of the driver's seat is the receiving terminal. Show variation. The calculation time of the received signal power of UWB is 30 nanoseconds including the time of the maximum peak position of the absolute value of the received signal, and the calculation time of the received signal power of a single frequency is 30 nanoseconds. In addition, the reference data from 0 to 12 seconds in FIG. It is a relative value in the state where

The amplitude of the reception power of the wireless terminal 200 at the foot of the driver's seat after 12 seconds is about 2 dB for UWB, and about 16 dB for a single frequency. That is, in UWB, fluctuations in received signal power are much smaller than in a single frequency due to the frequency diversity effect of UWB. Also, the difference between the UWB reference data and the average value of the received signal power after 12 seconds is 7d8, making it easy to detect that a passenger is in the driver's seat.

3 shows UWB (7.25 to 10.25 GHz) and single frequency (8.75 GHz CW ) shows the variation of the received power. The calculation time of the received signal power of UWB is 30 nanoseconds including the time of the maximum peak position of the absolute value of the received signal, and the calculation time of the received signal power of a single frequency is 30 nanoseconds. In addition, the reference data from 0 to 12 seconds in FIG. It is a relative value in the state where

The amplitude of the reception power of the wireless terminal 400 on the switch panel of the right rear door 70 after 12 seconds is approximately 1 dB for UWB and approximately 10 dB for a single frequency. That is, in UWB, fluctuations in received signal power are much smaller than in a single frequency due to the frequency diversity effect of UWB. Also, the difference between the UWB reference data and the average value of the received signal power after 12 seconds is 7d8, making it easy to detect that a passenger is in the driver's seat.

(Application of in-vehicle UWB wireless communication to occupant detection)
As described above (fluctuations in received power of radio waves at each wireless terminal position), it is possible to detect occupants by utilizing the stable fluctuations in received power of UWB depending on the presence or absence of occupants. It is possible to use intermittent or timely occupant detection results for big data analysis and autonomous driving by using an in-vehicle UWB wireless communication system without using dedicated devices or sensors.

On the other hand, if a dedicated device or sensor is used to detect the occupant, the manufacturing cost of the automobile will increase. Also, from FIGS. 2 and 3, it can be seen that the fluctuation of the received power of a single frequency is very large. Therefore, when occupants are detected using an in-vehicle wireless communication system based on narrowband radio, it is difficult to ensure certainty in determining whether occupants are present or not because the received power fluctuates greatly depending on the movements of the occupants. .

In other words, as explained in the section "Variation of received power of radio waves at each wireless terminal position" above, the received power of UWB is very stable against the movement of passengers. It is possible to increase the certainty of determining whether a person is seated or not. By using an in-vehicle UWB wireless communication system as a system for determining the presence or absence of passengers based on the received power of radio waves, it is possible to increase the certainty of determining whether or not there are passengers in the seats. In addition, by using the determination results of the presence or absence of the driver from both receiving terminal 200 and receiving terminal 400, it is possible to further increase the certainty of determining whether or not the driver is in the driver's seat. As described above, in the present embodiment, occupant detection is performed with high certainty using the new knowledge that the received power of UWB is extremely stable even with respect to the movement of the occupant.

(Configuration of wireless terminal)
As an example, the configuration of wireless terminal 100 is shown in FIG. However, radio terminal 200, radio terminal 300, radio terminal 400, and radio terminal 500 also have the same configuration as radio terminal 500. FIG.
The wireless terminal 100 includes an antenna 100i, a switch 100j, a wireless signal transmitter 100a, a wireless signal receiver 100b, and an in-vehicle wireless communication system controller 100h that is related to the UWB in-vehicle wireless communication system. Antenna 100i, switch 100j, radio signal transmitter 100a, and radio signal receiver 100b are parts used in both the UWB radio communication system and the occupant detection system. The in-vehicle wireless communication system control unit 100h controls in-vehicle wireless communication regardless of occupant detection.

The wireless terminal 100 also includes an occupant detection communication control unit 100c that only performs communication control of occupant detection information, a received power calculation unit 100d that calculates received power, and a reference power and received power that are compared to determine the presence or absence of a occupant. includes an occupant presence/absence determination unit 100e that performs The reference power is recorded in the reference power recording unit 100f. The reference power is the power received by the wireless terminal when there are no passengers in the vehicle, and is set or calibrated at the time of shipment from the factory of the vehicle or inspection at the dealer. Alternatively, the occupant detection system automatically measures and records the reference power when the car is parked unattended.

Further, wireless terminal 100 includes a wired information communication path 100g. The wired information communication path 100g is for transmitting the determination result of the presence or absence of a passenger to an application system for automatic driving or big data analysis. A metal wire or an optical fiber is used for the wired information communication path 100g. It is not essential for wireless terminals that do not play the role of transmitting the determination result of the presence or absence of a passenger to an application system for automatic driving or big data analysis. Also, the determination result of the presence or absence of a passenger may be transmitted by wireless communication instead of by wire.

5A and 5B are an example flow chart for detecting a driver in an occupant detection system. 5A and 5B, wireless terminal 200 and wireless terminal 400 calculate the received power of the UWB wireless signal transmitted from wireless terminal 100, and determine whether or not the driver is seated in the driver's seat.

5A and 5B, for example, the antenna 100i of the wireless terminal 100 is common for transmission and reception. The switch 100j switches the radio signal transmission section 100a or the radio signal reception section 100b to the antenna 100i in accordance with the transmission timing and the reception timing. However, the wireless terminal 100 may have a transmitting antenna and a receiving antenna, respectively. Also, the wireless terminal 200, the wireless terminal 300, the wireless terminal 400, and the wireless terminal 500 have the same configuration as the wireless terminal 100. FIG.

In steps S501, S502, and S503, an event occurs in wireless terminal 100 that requires wireless communication with wireless terminal 200 or wireless terminal 400. FIG. Alternatively, in steps S501, S502, and S503, an event that requires wireless communication with wireless terminal 100 occurs in wireless terminal 200 or wireless terminal 400. FIG.

For example, a case will be described in which an event occurs in wireless terminal 100 that requires wireless communication with wireless terminals 200 and 400 .

In step S<b>504 , the wireless terminal 100 starts calling the wireless terminal 200 to establish a wireless line link between the wireless terminals 100 and 200 .

In step S<b>505 , the wireless terminal 100 starts calling the wireless terminal 400 to establish a wireless line link between the wireless terminals 100 and 400 .
Note that the order of steps S504 and S505 may be reversed.

In step S<b>506 , wireless communication related to the event is performed from the wireless terminal 100 to the wireless terminal 200 .
In step S<b>507 , wireless communication related to the event is performed from the wireless terminal 100 to the wireless terminal 400 .
Note that the order of steps S506 and S507 may be reversed.

In step S508, the wireless terminal 200 calculates the received power value from the wireless terminal 100 using the received power calculator 200d. Any radio signal related to the event can be used as the radio signal for calculating the received power value. However, the radio terminal 100 can also transmit to the radio terminal 200 a dedicated radio signal for determining the presence or absence of a passenger. Then, the occupant presence/absence determination section 200e of the wireless terminal 200 determines whether or not there is an occupant based on the received power value calculated by the received power calculation section 200d.

In step S509, the wireless terminal 400 calculates the received power value from the wireless terminal 100 using the received power calculator 400d. Any radio signal related to the event can be used as the radio signal for calculating the received power value. However, the radio terminal 100 can also transmit to the radio terminal 400 a dedicated radio signal for determining the presence or absence of a passenger. Then, the occupant presence/absence determination section 400e of the wireless terminal 400 determines whether or not there is an occupant based on the received power value calculated by the received power calculation section 400d.

Note that the order of steps S508 and S509 may be reversed.

In step S510, the wireless terminal 200 transmits to the wireless terminal 100 the received power value calculated by the received power calculation unit 200d and the passenger presence/absence determination result determined by the passenger presence/absence determination unit 200e.

In step S511, the wireless terminal 400 transmits to the wireless terminal 100 the received power value calculated by the received power calculation unit 400d and the passenger presence/absence determination result determined by the passenger presence/absence determination unit 400e. The order of steps S510 and S511 may be reversed.

In steps S512, S513, and S514, link connections between the wireless terminal 100 and the wireless terminals 200 and 400 are terminated.

It is also possible to perform wireless communication between wireless terminal 100 and wireless terminals 200 and 400 in parallel. Multiple access methods in this case include TDMA (Time Division Multiple Access), CDMA (Code Division Multiple Access), FDMA (Frequency-Division Multiple Access), etc. Various techniques can be adopted.

In step S515, the occupant presence/absence determination unit 100e of the wireless terminal 100 determines whether or not the driver is seated based on the received power values received from the wireless terminals 200 and 400 or the occupant presence/absence determination results.

In this case, there are two driver presence/absence determination results, and if the two determination results match, the determination result is more reliable than the single determination result. Also, radio wave propagation measurement is performed in the course of vehicle development, and if the two determination results do not match, it is determined in advance which of the determination results of wireless terminal 200 and wireless terminal 400 should be prioritized.

In FIGS. 2 and 3, the difference between the reference power and the average value of the received power after 12 seconds when the driver is on board is both about 7 dB, so the difference is the same. If the differences are not equal, priority is given to determining the presence or absence of a driver of a wireless terminal with a large difference between the reference power and the average received power when a passenger is on board. This is because the larger the difference, the more useful the information.

Also, for example, priority may be given to the result of determining the presence or absence of a driver of a wireless terminal whose received power value fluctuates less when an occupant is seated.

In step S516, the occupant presence determination unit 100e of the wireless terminal 100 records the occupant presence determination result indicating whether or not the driver is seated in a recording unit (not shown) of the occupant presence determination unit 100e.

In step S517, the wireless terminal 100 transmits the result of driver presence/absence determination to the application system via the wired information communication path 100g or wireless communication (not necessarily UWB). In this case, wireless terminal 200 and wireless terminal 400 need not have wired information communication path 200g and wired information communication path 400g.

FIG. 6 is another example of a flow chart for detecting a driver in the occupant detection system. In FIG. 6, wireless terminal 100 calculates the received power of UWB wireless signals transmitted from wireless terminals 200 and 400, and determines whether or not the driver is seated in the driver's seat.

In steps S601, S602, and S603, an event occurs in wireless terminal 100 that requires wireless communication with wireless terminal 200 or wireless terminal 400. FIG. Alternatively, in steps S601, S602, and S603, an event occurs in wireless terminal 200 or wireless terminal 400 that requires wireless communication with wireless terminal 100. FIG.

For example, a case will be described in which an event occurs in wireless terminal 100 that requires wireless communication with wireless terminals 200 and 400 .

In step S<b>604 , the wireless terminal 100 starts calling the wireless terminal 200 to establish a wireless line link between the wireless terminals 100 and 200 .
In step S<b>605 , the wireless terminal 100 starts calling the wireless terminal 400 to establish a wireless line link between the wireless terminals 100 and 400 .
Note that the order of steps S604 and S605 may be reversed.

In step S<b>606 , wireless communication related to the event is performed from the wireless terminal 200 to the wireless terminal 100 .
In step S<b>607 , wireless communication related to the event is performed from the wireless terminal 400 to the wireless terminal 100 .
Note that the order of steps S606 and S607 may be reversed.

In steps S608, S609, and S610, link connections between the wireless terminal 100 and the wireless terminals 200 and 400 are terminated.

It is also possible to perform wireless communication between wireless terminal 100 and wireless terminals 200 and 400 in parallel. Multiple access methods in this case include TDMA (Time Division Multiple Access), CDMA (Code Division Multiple Access), FDMA (Frequency-Division Multiple Access), etc. Various techniques can be adopted.

In step S611, the radio terminal 100 calculates received power values from the radio terminal 200 and the radio terminal 400 using the received power calculator 100d. Any radio signal related to the event can be used as the radio signal for calculating the received power value. However, wireless terminal 200 and wireless terminal 400 can also transmit a dedicated wireless signal for determining the presence or absence of passengers to wireless terminal 100 . Based on the received power values of the radio signals received from the radio terminals 200 and 400, the occupant presence determination unit 100e of the radio terminal 100 determines whether the driver is seated.

In this case, there are two driver presence/absence determination results, and if the two determination results match, the determination result is more reliable than the single determination result. Also, radio wave propagation measurement is performed in the course of vehicle development, and if the two determination results do not match, it is determined in advance which of the determination results of wireless terminal 200 and wireless terminal 400 should be prioritized.

In step S612, the occupant presence determination unit 100e of the wireless terminal 100 records the occupant presence determination result indicating whether or not the driver is seated in a recording unit (not shown) of the occupant presence determination unit 100e.

In step S613, the wireless terminal 100 transmits the result of driver presence/absence determination to the application system via the wired information communication path 100g or wireless communication (not necessarily UWB). In this case, wireless terminal 200 and wireless terminal 400 need not have wired information communication path 200g and wired information communication path 400g.

7A and 7B are yet another example of a flow chart for detecting a driver in an occupant detection system. 5 and 6 show the case where the wireless terminal 100 involved in the occurrence of a communication event is the point of contact with the application system. Figures 7A and 7B use a dedicated terminal that collects and centrally manages determination information on the presence or absence of occupants in each seat, regardless of the occurrence of an event, and transfers the determination information on the presence or absence of occupants in each seat to the application system. 2 is a flow chart of an occupant detection system in a case; In other words, FIGS. 7A and 7B are flow charts in which the result of driver presence determination generated at wireless terminal 200 and wireless terminal 400 in FIG. .

In steps S701, S702, and S703, an event occurs in wireless terminal 100 that requires wireless communication with wireless terminal 200 or wireless terminal 400. FIG. Alternatively, in steps S701, S702, and S703, an event that requires wireless communication with wireless terminal 100 occurs in wireless terminal 200 or wireless terminal 400. FIG.

For example, a case will be described in which an event occurs in wireless terminal 100 that requires wireless communication with wireless terminals 200 and 400 .

In step S<b>704 , the wireless terminal 100 starts calling the wireless terminal 200 to establish a wireless line link between the wireless terminals 100 and 200 .
In step S<b>705 , the wireless terminal 100 starts calling the wireless terminal 400 to establish a wireless line link between the wireless terminals 100 and 400 .
Note that the order of steps S704 and S705 may be reversed.

In step S706, wireless communication related to the event is performed from the wireless terminal 100 to the wireless terminal 200. FIG.
In step S<b>707 , wireless communication related to the event is performed from the wireless terminal 100 to the wireless terminal 400 .
Note that the order of steps S706 and S707 may be reversed.

In step S708, the wireless terminal 200 calculates the received power value from the wireless terminal 100 using the received power calculator 200d. Any radio signal related to the event can be used as the radio signal for calculating the received power value. However, the radio terminal 100 can also transmit to the radio terminal 200 a dedicated radio signal for determining the presence or absence of a passenger. Then, the occupant presence/absence determination section 200e of the wireless terminal 200 determines whether or not there is an occupant based on the received power value calculated by the received power calculation section 200d.

In step S709, the occupant presence determination unit 200e of the wireless terminal 200 records the received power value and the occupant presence determination result indicating whether or not the driver is seated in a recording unit (not shown) of the occupant presence determination unit 200e.

In step S710, the link connection between wireless terminal 100 and wireless terminal 200 is terminated.

In step S711, the radio terminal 400 calculates the received power value from the radio terminal 100 using the received power calculator 400d. Any radio signal related to the event can be used as the radio signal for calculating the received power value. However, the radio terminal 100 can also transmit to the radio terminal 400 a dedicated radio signal for determining the presence or absence of a passenger. Then, the occupant presence/absence determining section 400e of the wireless terminal 400 determines whether or not there is an occupant based on the received power value calculated by the received power calculation section 200d.

In step S712, the occupant presence determination unit 400e of the wireless terminal 400 records the received power value and the occupant presence determination result indicating whether or not the driver is seated in a recording unit (not shown) of the occupant presence determination unit 400e.

At step S713, the link connection between the wireless terminal 100 and the wireless terminal 400 is terminated.

In step S714, the link connections between wireless terminal 100 and wireless terminals 200 and 400 are terminated.

In step S 715 , the wireless terminal 200 starts calling the collection terminal 600 to establish a wireless line link between the wireless terminal 200 and the collection terminal 600 .
In step S<b>716 , the wireless terminal 400 starts calling the collection terminal 600 to establish a wireless line link between the wireless terminal 400 and the collection terminal 600 .
Note that the order of steps S714 and S715 may be reversed.

In step S<b>717 , the wireless terminal 200 transmits to the collection terminal 600 the determination result of the occupant presence determined by the occupant presence determination unit 200 e.

In step S<b>718 , the wireless terminal 400 transmits to the collection terminal 600 the determination result of the occupant presence determined by the occupant presence determination unit 400 e. The order of steps S717 and S718 may be reversed.

In steps S719, S720, and S721, link connections between the collection terminal 600 and the wireless terminals 200 and 400 are terminated.

In step S722, the collection terminal 600 transmits the driver presence/absence determination result to the application system via the wired information communication path 600g or wireless communication (not necessarily UWB). In this case, wireless terminal 100, wireless terminal 200 and wireless terminal 400 do not need to have wired information communication path 100g, wired information communication path 200g and wired information communication path 400g.

FIG. 8 is yet another example of a flow chart for detecting a driver in an occupant detection system. 5 and 6 show the case where the wireless terminal 100 involved in the occurrence of a communication event is the point of contact with the application system. FIG. 8 shows the occupant when using a dedicated terminal that collects and centrally manages information on the presence or absence of occupants in each seat, regardless of the occurrence of an event, and transfers the information on the presence or absence of occupants in each seat to the application system. FIG. 11 is a flowchart of another example detection system; FIG. That is, FIG. 8 is a flow chart modified in FIG. 6 so that the dedicated collection terminal 600 transmits to the application system the determination result of the presence or absence of the driver generated at the wireless terminal 100 .

In steps S801, S802, and S803, an event occurs in wireless terminal 100 that requires wireless communication with wireless terminal 200 or wireless terminal 400. FIG. Alternatively, in steps S801, S802, and S803, an event that requires wireless communication with wireless terminal 100 occurs in wireless terminal 200 or wireless terminal 400. FIG.

For example, a case will be described in which an event occurs in wireless terminal 100 that requires wireless communication with wireless terminals 200 and 400 .

In step S804, the wireless terminal 100 starts to call the wireless terminal 200, and a wireless line link is established between the wireless terminals 100 and 200. FIG.
In step S805, the wireless terminal 100 starts to call the wireless terminal 400, and a wireless line link is established between the wireless terminals 100 and 400. FIG.
Note that the order of steps S804 and S805 may be reversed.

In step S806, wireless communication related to the event is performed from the wireless terminal 200 to the wireless terminal 100. FIG.
In step S<b>807 , wireless communication related to the event is performed from the wireless terminal 400 to the wireless terminal 100 .
Note that the order of steps S806 and S807 may be reversed.

In steps S808, S809, and S810, link connections between the wireless terminal 100 and the wireless terminals 200 and 400 are terminated.

It is also possible to perform wireless communication between wireless terminal 100 and wireless terminals 200 and 400 in parallel. Multiple access methods in this case include TDMA (Time Division Multiple Access), CDMA (Code Division Multiple Access), FDMA (Frequency-Division Multiple Access), etc. Various techniques can be adopted.

In step S<b>811 , the wireless terminal 100 starts calling the collection terminal 600 to establish a wireless line link between the wireless terminal 100 and the collection terminal 600 .

In step S<b>812 , the radio terminal 100 transmits to the collection terminal 600 the passenger presence/absence determination result determined by the passenger presence/absence determining unit 100 e based on the received power values from the wireless terminals 200 and 400 .

In steps S813 and S814, the link connection between the collection terminal 600 and the wireless terminal 100 is terminated.

In step S815, the collection terminal 600 transmits the driver presence/absence determination result to the application system via the wired information communication path 600g or wireless communication (not necessarily UWB). In this case, wireless terminal 100, wireless terminal 200 and wireless terminal 400 do not need to have wired information communication path 100g, wired information communication path 200g and wired information communication path 400g.

An example of the configuration of the collection terminal 600 is shown in FIG. The collection terminal 600 includes an antenna 600i, a switch 600j, a radio signal transmitter 600a, a radio signal receiver 600b, and an occupant detection communication controller 600c. The determination result of the passenger presence from each wireless terminal is recorded in the passenger detection result recording unit 600h. The determination result of the presence or absence of an occupant in each seat is transmitted from the occupant detection communication control unit 600c to the application system via the wired information communication path 600g or using an in-vehicle wireless communication system (not necessarily UWB).

(Modification 1)
In the above embodiment, the wireless terminal 200 placed at the foot of the driver's seat is used to detect the driver in the driver's seat. A passenger seat occupant detection system can be realized. That is, by performing UWB wireless communication between the wireless terminal 100 and the wireless terminal 300, it is possible to detect the occupant in the front passenger seat.

Furthermore, in the above embodiment, the wireless terminal 400 arranged on the switch panel of the right rear door 70 is used in order to detect the driver in the driver's seat. A front passenger seat occupant detection system can be realized by using the wireless terminal 500 placed in the . That is, by performing UWB wireless communication between the wireless terminal 100 and the wireless terminal 500, it is possible to detect the occupant in the front passenger seat.

(Modification 2)
By arranging the UWB wireless terminal at a position where fluctuations in received signal power due to the presence or absence of passengers can be stably observed, it is possible to detect passengers in the rear seats of the vehicle. Also, by placing a UWB wireless terminal at a position where fluctuations in received signal power due to the presence or absence of passengers can be stably observed, it is possible to detect passengers in the third row in a minivan type automobile. Whether or not fluctuations in received signal power due to the presence or absence of passengers can be stably observed can be determined in advance by performing radio wave propagation measurement inside the vehicle.

(Modification 3)
In the above embodiment, an automobile is used as an example of a vehicle for occupant detection. However, vehicles to which the occupant detection system can be applied are not limited to automobiles. For example, by appropriately arranging wireless terminals using UWB radio in the interior space of buses, railways, aircraft, spaceships, ships, and submersibles, it is possible to perform seat-by-seat detection without using devices or sensors dedicated to occupant detection. It is possible to realize human body detection. That is, it is possible to achieve human body detection for each seat when the received signal power falls below a predetermined reference power value during UWB radio operation.

Although the embodiments have been described in detail with reference to the drawings, the present invention is not limited by the contents described in the above embodiments. In addition, the components described above include components that can be easily assumed by those skilled in the art and components that are substantially the same. Furthermore, the configurations described above can be combined as appropriate. In addition, various omissions, substitutions, or changes in configuration can be made without departing from the gist of the present invention.

INDUSTRIAL APPLICABILITY The present invention is extremely useful when used in an occupant detection system and occupant detection method that enable detection of the presence or absence of an occupant at each seat in a vehicle without using a dedicated camera or sensor.

20... Engine room 30... Firewall 40... Center console 50... Trunk 60... Right front door 70... Right rear door 80... Left front door 90... Left Rear seat doors 100, 200, 300, 400, 500 Wireless terminals 100a, 600a Wireless signal transmitters 100b, 600b Wireless signal receivers 100c, 600c Passenger detection communication controller 100d Received power calculation unit 100e Occupant presence/absence determination unit 100f Reference power recording unit 100g Wired information communication path 100h, 600h In-vehicle wireless communication system control unit 100i, 600i Antenna 100j , 600j switch 600 collection terminal

Claims (4)

An occupant detection system in a communication system that performs in-vehicle communication using UWB (Ultra Wide Band) radio,
a wireless terminal that transmits a wireless signal of UWB wireless;
a plurality of other wireless terminals that receive the wireless signal transmitted from the wireless terminal;
The plurality of other wireless terminals determine that there is an occupant in the vehicle when the received power value of the wireless signal is equal to or less than a predetermined reference power value ;
The wireless terminal receives the received power value and a determination result regarding the presence or absence of a passenger in the vehicle from each of the plurality of other wireless terminals, and receives the determination result regarding the presence or absence of a passenger in the vehicle from each of the plurality of other wireless terminals. Based on the judgment result, judge whether there is a passenger in the vehicle,
When the judgment result regarding the presence or absence of passengers in the vehicle from each of the plurality of other radio terminals is different, the radio terminal determines the average value of the received power values from each of the plurality of other radio terminals. An occupant detection system , wherein priority is given to the determination result from the other wireless terminal having a larger difference . The radio terminal and the other radio terminal are arranged at a position where communication is performed not by line-of-sight waves of the radio signal but by waves diffracted and reflected by the occupant and the vehicle when the occupant is present. The occupant detection system of Claim 1. Receiving the determination results regarding the presence or absence of occupants in the vehicle from each of the plurality of other wireless terminals, and transmitting the determination results regarding the presence or absence of occupants in the vehicle from each of the plurality of other wireless terminals to an application system. 3. The occupant detection system of claim 1 or 2 , including a collection terminal. An occupant detection method in a communication method for performing in-vehicle communication using UWB (Ultra Wide Band) radio,
a wireless terminal transmitting a radio signal for UWB radio;
a plurality of other wireless terminals receiving the wireless signal transmitted from the wireless terminal;
The plurality of other wireless terminals determine that there is an occupant in the vehicle when the received power value of the wireless signal is equal to or less than a predetermined reference power value ;
The wireless terminal receives the received power value and a determination result regarding the presence or absence of a passenger in the vehicle from each of the plurality of other wireless terminals, and receives the determination result regarding the presence or absence of a passenger in the vehicle from each of the plurality of other wireless terminals. Based on the judgment result, judge whether there is a passenger in the vehicle,
When the judgment result regarding the presence or absence of passengers in the vehicle from each of the plurality of other radio terminals is different, the radio terminal determines the average value of the received power values from each of the plurality of other radio terminals. An occupant detection method , wherein priority is given to the determination result from the other wireless terminal having a larger difference .

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