System and method for vehicle occupancy detection

Abstract

A system for detecting one or more occupants in a vehicle may include a plurality of wireless modules and a controller in electrical communication with the plurality of wireless modules. The controller is programmed to perform one or more rounds of sensing. Each of the one or more sensing wheels includes communication between at least two of the plurality of wireless modules. The controller is programmed to determine a presence of one or more occupants in the vehicle based at least in part on the one or more wheel sensing.

Description

Technical Field

[0001] The present invention relates to a system and method for occupant detection in a vehicle. Background Art

[0002] Vehicle occupancy detection systems are used to detect the presence of occupants within a vehicle. In some examples, a vehicle occupancy detection system can be used to adjust an airbag deployment routine. For example, a vehicle occupancy detection system can be used to prevent airbag deployment for unoccupied seats. In another example, a vehicle occupancy detection system can be used to adjust one or more airbag deployment parameters based on characteristics of an occupant (e.g., weight). In yet another example, a vehicle occupancy detection system can be used to notify a vehicle operator of an occupant remaining in the vehicle (e.g., a child). In some embodiments, a vehicle occupancy detection system utilizes weight and / or pressure sensors incorporated into one or more vehicle seats to detect occupants. However, weight and / or pressure sensors may be unreliable for detecting occupants with a relatively low weight (e.g., children and infants). Additionally, weight and / or pressure sensors may not be able to distinguish between an occupant and other weight and / or pressure sources, such as cargo placed on a vehicle seat.

[0003] Accordingly, while current vehicle occupancy detection systems achieve their intended purposes, there is still a need for a new and improved system and method for detecting one or more occupants in a vehicle. Summary of the Invention

[0004] In accordance with some aspects, the present invention provides a system for detecting one or more occupants in a vehicle. The system can include a plurality of wireless modules and a controller in electrical communication with the plurality of wireless modules. The controller is programmed to perform one or more rounds of sensing. Each round of the one or more rounds of sensing includes communication between at least two of the plurality of wireless modules. The controller is programmed to determine the presence of one or more occupants in the vehicle based at least in part on the one or more rounds of sensing.

[0005] In another aspect of the present invention, to perform one or more rounds of sensing, the controller is further programmed to determine a plurality of participating wireless modules. The plurality of participating wireless modules is a subset of the plurality of wireless modules. The plurality of participating wireless modules includes at least two of the plurality of wireless modules. To perform one or more rounds of sensing, the controller is further programmed to transmit one or more signals between at least two of the plurality of participating wireless modules. To perform one or more rounds of sensing, the controller is further programmed to determine a plurality of Channel State Information (CSI) values based at least in part on the one or more signals.

[0006] In another aspect of the present invention, to determine a plurality of participating wireless modules, the controller is further programmed to determine a predicted position of one or more occupants within the passenger compartment of the vehicle. To determine a plurality of participating wireless modules, the controller is further programmed to determine the plurality of participating wireless modules at least in part based on the predicted position of one or more occupants within the passenger compartment of the vehicle.

[0007] In another aspect of the present invention, the system further includes one or more vehicle sensors in electrical communication with the controller. To determine a predicted position of one or more occupants within the passenger compartment of the vehicle, the controller is further programmed to perform one or more measurements using the one or more vehicle sensors. To determine a predicted position of one or more occupants within the passenger compartment of the vehicle, the controller is further programmed to determine the predicted position of one or more occupants within the passenger compartment of the vehicle at least in part based on the one or more measurements.

[0008] In another aspect of the present invention, to transmit one or more signals between at least two of the plurality of participating wireless modules, the controller is further programmed to transmit one or more signals between each combination consisting of two of the plurality of participating wireless modules.

[0009] In another aspect of the present invention, to transmit one or more signals between at least two of the plurality of participating wireless modules, the controller is further programmed to change a frequency band of the one or more signals between at least two of one or more rounds of sensing.

[0010] In another aspect of the present invention, to determine the presence of one or more occupants in the vehicle, the controller is further programmed to perform an inverse Fourier transform on a plurality of CSI values to determine a time-domain power delay profile. To determine the presence of one or more occupants in the vehicle, the controller is further programmed to identify a motion signature at least in part based on the time-domain power delay profile. To determine the presence of one or more occupants in the vehicle, the controller is further programmed to determine the presence of one or more occupants in the vehicle at least in part based on the motion signature.

[0011] In another aspect of the present invention, one or more of the plurality of wireless modules is at least one of the following: a digital Wireless Local Area Network (WLAN) transceiver system configured to implement a wireless communication protocol; and a signal conversion device configured to convert a signal between at least two frequency bands.

[0012] In another aspect of the present invention, one or more of the plurality of wireless modules are located within the passenger compartment of the vehicle. The position of each of the plurality of wireless modules is determined at least in part based on an estimated sensing signal-to-noise ratio (SSNR) at one or more target locations within the passenger compartment of the vehicle.

[0013] In another aspect of the present invention, the SSNR at a target location within the passenger compartment of the vehicle is defined as:

[0014]

[0015] where SSNR T is the SSNR at the target location within the passenger compartment of the vehicle, γ 12 is the distance between a first wireless module and a second wireless module among the plurality of wireless modules, γ 1T is the distance between the first wireless module among the plurality of wireless modules and the target location, and γ 2T is the distance between the second wireless module among the plurality of wireless modules and the target location.

[0016] According to some aspects, the present invention provides a method for detecting one or more occupants in a vehicle. The method may include performing one or more rounds of sensing. Each round of the one or more rounds of sensing includes communication between at least two of the plurality of wireless modules. The method may also include determining the presence of one or more occupants in the vehicle at least in part based on the one or more rounds of sensing.

[0017] In another aspect of the present invention, performing one or more rounds of sensing may further include determining a plurality of participating wireless modules. The plurality of participating wireless modules is a subset of the plurality of wireless modules. The plurality of participating wireless modules includes at least two of the plurality of wireless modules. Performing one or more rounds of sensing may further include transmitting one or more signals between at least two of the plurality of participating wireless modules. Performing one or more rounds of sensing may further include determining a plurality of channel state information (CSI) values at least in part based on the one or more signals.

[0018] In another aspect of the present invention, determining the plurality of participating wireless modules may further include determining a predicted position of one or more occupants within the passenger compartment of the vehicle. Determining the plurality of participating wireless modules may further include determining the plurality of participating wireless modules at least in part based on the predicted position of one or more occupants within the passenger compartment of the vehicle.

[0019] In another aspect of the present invention, determining a predicted position of one or more occupants within a vehicle passenger compartment may further include performing one or more measurements using one or more vehicle sensors. The one or more vehicle sensors include at least one of the following: a vehicle camera, a vehicle microphone, and a vehicle seat occupancy sensor. Determining a predicted position of one or more occupants within the vehicle passenger compartment may further include determining the predicted position of one or more occupants within the vehicle passenger compartment at least in part based on the one or more measurements.

[0020] In another aspect of the present invention, transmitting one or more signals between at least two of a plurality of participating wireless modules may further include transmitting one or more signals between each combination consisting of two of the plurality of participating wireless modules.

[0021] In another aspect of the present invention, transmitting one or more signals between at least two of a plurality of participating wireless modules may further include changing a frequency band of the one or more signals between at least two of one or more rounds of sensing.

[0022] In another aspect of the present invention, determining the presence of one or more occupants in a vehicle may further include performing an inverse Fourier transform on a plurality of CSI values to determine a time-domain power delay profile. Determining the presence of one or more occupants in the vehicle may further include identifying a motion signature at least in part based on the time-domain power delay profile. Determining the presence of one or more occupants in the vehicle may further include determining the presence of one or more occupants in the vehicle at least in part based on the motion signature.

[0023] According to some aspects, the present invention provides a system for detecting one or more occupants in a vehicle. The system may include a plurality of wireless modules and one or more vehicle sensors. The one or more vehicle sensors include at least one of the following: a vehicle camera, a vehicle microphone, and a vehicle seat occupancy sensor. The system may further include a controller in electrical communication with the plurality of wireless modules and the one or more vehicle sensors. The controller is programmed to perform one or more measurements using the one or more vehicle sensors. The controller is further programmed to determine a predicted position of one or more occupants within the vehicle passenger compartment at least in part based on the one or more measurements. The controller is further programmed to determine a plurality of participating wireless modules at least in part based on the predicted position of one or more occupants within the vehicle passenger compartment. The plurality of participating wireless modules is a subset of the plurality of wireless modules. The plurality of participating wireless modules includes at least two of the plurality of wireless modules. The controller is further programmed to transmit one or more signals between at least two of the plurality of participating wireless modules. The controller is further programmed to determine a plurality of channel state information (CSI) values at least in part based on the one or more signals. The controller is further programmed to determine the presence of one or more occupants in the vehicle at least in part based on the plurality of CSI values.

[0024] In another aspect of the present invention, to determine the presence of one or more occupants in a vehicle, the controller is further programmed to perform an inverse Fourier transform on a plurality of CSI values to determine a time-domain power delay profile. The time-domain power delay profile includes one or more reflections of one or more signals. To determine the presence of one or more occupants in a vehicle, the controller is further programmed to identify motion signatures at least in part based on one or more reflections in the time-domain power delay profile. To determine the presence of one or more occupants in a vehicle, the controller is further programmed to determine the presence of one or more occupants in the vehicle at least in part based on the motion signatures.

[0025] In another aspect of the present invention, one or more of the plurality of wireless modules are located within the passenger compartment of the vehicle. The position of each of the plurality of wireless modules is determined at least in part based on an estimated sensed signal-to-noise ratio (SSNR) at one or more target locations within the passenger compartment of the vehicle.

[0026] From the description provided herein, further application areas will become apparent. It should be understood that these descriptions and specific examples are for illustrative purposes only and are not intended to limit the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present invention in any way.

[0028] Figure 1 is a schematic diagram of a system for detecting one or more occupants in a vehicle according to an exemplary embodiment;

[0029] Figure 2 is a schematic diagram of a digital WLAN transceiver system according to an exemplary embodiment;

[0030] Figure 3 is according to an exemplary embodiment having Figure 2 a signal conversion device of a digital WLAN transceiver system;

[0031] Figure 4 is a schematic diagram of a passenger compartment of a vehicle showing a plurality of wireless modules according to an exemplary embodiment;

[0032] Figure 5 is a flowchart of a method for detecting one or more occupants in a vehicle according to an exemplary embodiment;

[0033] Figure 6 is a graph showing a frequency-domain plot of a set of multiple channel state information (CSI) values for a single sensing round and a time-domain plot of the power delay profile for a single sensing round according to an exemplary embodiment;

[0034] Figure 7is a diagram showing an exemplary time series power delay profile according to an exemplary embodiment; and

[0035] Figure 8 is a flow chart of a method for performing a round of sensing according to an exemplary embodiment. DETAILED DESCRIPTION

[0036] The following description is merely exemplary in nature and is not intended to limit the invention, its application, or uses.

[0037] In aspects of the present invention, it is advantageous to detect the presence and / or location of an occupant within a vehicle passenger compartment. To this end, a vehicle may be equipped with various sensors for occupant detection, such as for child presence detection. However, an occupant sensor may not always detect the presence of an occupant. For example, an occupant may be blocked by a blanket or other object, hindering detection by a vision sensor (e.g., a camera). Additionally, an occupant may be very light (e.g., a child or infant), hindering detection by a weight or pressure-based sensor. Accordingly, the present invention provides a new and improved system and method for detecting one or more occupants in a vehicle based on the detection of movement in the vehicle using wireless communication technology.

[0038] Reference Figure 1 , there is illustrated a system for detecting one or more occupants in a vehicle, and the system is generally designated by reference numeral 10. System 10 is shown in conjunction with an exemplary vehicle 12. Although illustrated as a passenger vehicle, it should be understood that vehicle 12 may be any type of vehicle without departing from the scope of the present invention. System 10 generally includes a controller 14, a plurality of wireless modules 16, and one or more vehicle sensors 18.

[0039] The controller 14 is configured to implement a method 100 for detecting one or more occupants in a vehicle as will be described hereinafter. The controller 14 includes at least one processor 20 and a non-transitory computer-readable storage device or medium 22. The processor 20 can be a custom or off-the-shelf processor, a central processing unit (CPU), a graphics processing unit (GPU), an auxiliary processor among several processors associated with the controller 14, a semiconductor-based microprocessor (in the form of a microchip or chipset), a macroprocessor, a combination thereof, or generally a device for executing instructions. The computer-readable storage device or medium 22 can include volatile and non-volatile memories such as, for example, read-only memory (ROM), random access memory (RAM), and keep-alive memory (KAM). KAM is a persistent or non-volatile memory that can be used to store various operating variables when the processor 20 is powered down. The computer-readable storage device or medium 22 can be implemented using multiple storage devices such as programmable read-only memory (PROM), electrically erasable PROM (EEPROM), electrically erasable PROM (EEPROM), flash memory, or other electrical, magnetic, optical, or combined storage devices capable of storing data used by the controller 14 to control various systems of the vehicle 12, some of which data represents executable instructions. The controller 14 can also be composed of multiple controllers that are electrically connected to each other. The controller 14 can be interconnected with additional systems and / or controllers of the vehicle 12, thereby allowing the controller 14 to access data such as the speed, acceleration, braking, and steering angle of the vehicle 12.

[0040] The controller 14 is in electrical communication with a plurality of wireless modules 16 and one or more vehicle sensors 18. In an exemplary embodiment, electrical communication is established using, for example, a CAN network, a FLEXRAY network, a local area network (e.g., WiFi, Ethernet, etc.), a serial peripheral interface (SPI) network, and the like. It should be understood that various additional wired and wireless technologies and communication protocols for communicating with the controller 14 are within the scope of the present invention.

[0041] The plurality of wireless modules 16 are configured to communicate wirelessly with devices inside and / or outside the vehicle 12. In an exemplary embodiment, one or more of the plurality of wireless modules 16 are vehicle communication systems. Within the scope of the present invention, the vehicle communication system is configured to communicate with other systems inside and / or outside the vehicle 12. For example, the vehicle communication system includes the ability to communicate with other vehicles (“V2V” communication), infrastructure (“V2I” communication), remote systems of a remote call center (e.g., ON-STAR of General Motors), and / or personal devices.

[0042] In general, the term vehicle-to-everything communication ("V2X" communication) refers to communication between vehicle 12 and any remote system (e.g., vehicle, infrastructure, and / or remote system). In certain embodiments, vehicle communication system 22 is a wireless communication system configured to communicate via a wireless local area network (WLAN) using the IEEE 802.11 standard or by using cellular data communication (e.g., using the GSMA standard such as SGP.02, SGP.22, SGP.32, etc.). Accordingly, the vehicle communication system may also include an embedded universal integrated circuit card (eUICC) configured to store at least one cellular connection configuration profile, such as an embedded subscriber identity module (eSIM) profile.

[0043] The vehicle communication system is also configured to communicate via a personal area network (e.g., Bluetooth), near field communication (NFC), and / or any additional type of radio frequency communication. However, additional or alternative communication methods such as dedicated short range communication (DSRC) channels and / or mobile telecommunication protocols based on the 3rd Generation Partnership Project (3GPP) standards are also considered within the scope of the present invention. A DSRC channel refers to a one-way or two-way short-to-medium range wireless communication channel designed for automotive use, along with a corresponding set of protocols and standards. 3GPP refers to a partnership between multiple standards organizations that develop mobile telecommunication protocols and standards. The structure of the 3GPP standards is "releases". Accordingly, communication methods based on 3GPP Releases 14, 15, 16, and / or future 3GPP releases are considered within the scope of the present invention.

[0044] Accordingly, the vehicle communication system may include one or more antennas and / or communication transceivers for receiving and / or transmitting signals, such as cooperative sensing messages (CSM). The vehicle communication system is configured to wirelessly transmit information between vehicle 12 and another vehicle. In addition, the vehicle communication system is configured to wirelessly transmit information between vehicle 12 and infrastructure or other vehicles. In addition, the vehicle communication system is configured to wirelessly transmit information between one or more of the plurality of wireless modules 16.

[0045] In another exemplary embodiment, one or more of the plurality of wireless modules 16 are digital wireless local area network (WLAN) transceiver systems. Refer to Figure 2, shows a schematic diagram of a digital WLAN transceiver system 24a. In an exemplary embodiment, the digital WLAN transceiver system 24a includes a wireless control module 26 capable of implementing a wireless communication protocol, which uses training signals to perform channel state information (CSI) estimation. Within the scope of the present invention, the training signal is a known signal transmitted for the purpose of CSI estimation. Within the scope of the present invention, the CSI value describes how a wireless signal propagates in the environment. More specifically, the CSI value represents, for example, the combined effects of scattering, fading, and power attenuation. In other words, CSI is an estimate of the frequency response of the transmission channel between two or more transceivers. In a non-limiting example, the digital WLAN transceiver system 24a supports a wireless communication protocol according to one or more of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless local area network (WLAN) related standards. In an exemplary embodiment, the digital WLAN transceiver system 24a includes at least one wireless transceiver module 28 in electrical communication with the wireless control module 26. The at least one wireless transceiver module 28 is configured to transmit and receive signals on a first frequency band B1 (e.g., the 2.4 GHz band). In another exemplary embodiment, the digital WLAN transceiver system 24a includes at least two wireless transceiver modules 28, as Figure 2 shown. The first wireless transceiver module 28a is configured to transmit and receive signals on the first frequency band B1. The second wireless transceiver module 28b is configured to transmit and receive signals on a second frequency band B2 (e.g., the 5 GHz band).

[0046] In an exemplary embodiment, the first frequency band B1 and / or the second frequency band B2 are divided into a plurality of sub-frequencies (i.e., sub-carriers). The data to be transmitted is divided into a plurality of data streams. Each of the plurality of data streams is modulated using one of the plurality of sub-carriers for transmission. In an exemplary embodiment, the training signal for performing channel state information (CSI) estimation is transmitted on one or more sub-carriers of each frequency band. In a non-limiting example, three sub-carriers within the first frequency band B1 and / or the second frequency band B2 are used for transmitting and / or receiving the training signal. In another non-limiting example, all sub-carriers within the first frequency band B1 and / or the second frequency band B2 are used for transmitting and / or receiving the training signal.

[0047] Referring again to Figure 1 , in another exemplary embodiment, one or more of the plurality of wireless modules 16 are signal conversion devices. Referring to Figure 3 , shows a schematic diagram of a signal conversion device 24b having a digital WLAN transceiver system 24a. The signal conversion device 24b includes a power supply 30, at least two antennas (i.e., a first antenna 32a and a second antenna 32b), and a conversion circuit 34.

[0048] The power supply 30 is used to supply power to the conversion circuit 34. In an exemplary embodiment, the power supply 30 is connected to the electrical system of the vehicle 12, such as the 12-volt electrical system of the vehicle 12. In another exemplary embodiment, the power supply 30 is a battery. In another exemplary embodiment, the power supply 30 is an energy harvesting device configured to harvest energy from, for example, radio frequency signals, light, vibration, heat, etc., and convert the harvested energy into electrical energy. The power supply 30 is in electrical communication with the conversion circuit 34. It should be understood that without departing from the scope of the present invention, the power supply 30 can be any device capable of supplying power to the conversion circuit 34.

[0049] The at least two antennas (i.e., the first antenna 32a and the second antenna 32b) are used to transmit and / or receive wireless communication signals. As Figure 3 shown, the first antenna 32a is used to receive wireless communication signals on the first frequency band B1, such as the wireless communication signals transmitted by the first wireless transceiver module 28a. As Figure 3 shown, the second antenna 32b is used to transmit wireless communication signals on the second frequency band B2, such as the wireless communication signals that can be received by the second wireless transceiver module 28b. As will be discussed in more detail below, the first antenna 32a and the second antenna 32b are in electrical communication with the conversion circuit 34.

[0050] The conversion circuit 34 is used to convert wireless communication signals between the first frequency band B1 and the second frequency band B2. In an exemplary embodiment, the conversion circuit 34 includes a mixer 36, an oscillator 38, a first amplifier 40a, a second amplifier 40b, a first bandpass filter 42a, and a second bandpass filter 42b. In an exemplary embodiment, the first amplifier 40a and the first bandpass filter 42a are encapsulated as a monolithic integrated circuit, referred to as a combined amplifier with a bandpass filter (LNA+BPF) 44.

[0051] The mixer 36 is used to convert the signal received using the first antenna 32a between the first frequency band B1 and the second frequency band B2, also known as heterodyning. In an exemplary embodiment, the mixer 36 is a passive mixer including passive components (such as diodes). In another exemplary embodiment, the mixer 36 is an active mixer including active components (such as transistors). In a non-limiting example, the mixer 36 generates a signal at the mixer output of the mixer 36, which is the product of two input signals provided to the first mixer input and the second mixer input. The first mixer input of the mixer 36 is in electrical communication with the oscillator 38. The second mixer input of the mixer 36 is in electrical communication with the first amplifier 40a. The mixer output of the mixer 36 is in electrical communication with the second bandpass filter 42b.

[0052] Oscillator 38 is used to generate an oscillation signal with a known frequency for mixer 36. In an exemplary embodiment, oscillator 38 is referred to as a local oscillator. In a non-limiting example, oscillator 38 is a crystal oscillator that utilizes a piezoelectric element to generate the oscillation signal. In another non-limiting example, oscillator 38 is a variable frequency oscillator capable of generating an oscillation signal with a variable frequency. Oscillator 38 is in electrical communication with a first mixer input of mixer 36. In an exemplary embodiment, oscillator 38 receives power from power supply 30.

[0053] First amplifier 40a is used to amplify the signal received by first antenna 32a. In an exemplary embodiment, first amplifier 40a is a low noise amplifier (LNA). The LNA is designed to amplify extremely low power signals, such as the current generated by the antenna, without significantly degrading the signal-to-noise ratio of the signal. In a non-limiting example, first amplifier 40a further includes a filter or other electronic circuitry designed to remove unwanted signals and / or noise from the current generated by first antenna 32a. In a non-limiting example, power supply 30 supplies power and a DC bias signal to first amplifier 40a. It should be understood that various other types and / or topologies of amplifiers may be used to amplify the current generated by first antenna 32a. First amplifier 40a is in electrical communication with first bandpass filter 42a and a second mixer input of mixer 36.

[0054] Second amplifier 40b is used to amplify the signal generated by mixer 36 for transmission by second antenna 32b. In a non-limiting example, power supply 30 supplies power and a DC bias signal to second amplifier 40b. It should be understood that various other types and / or topologies of amplifiers may be used to amplify the electrical signal generated by mixer 36 for transmission by second antenna 32b. Second amplifier 40b is in electrical communication with second bandpass filter 42b and second antenna 32b.

[0055] First bandpass filter 42a is used to filter the signal received by first antenna 32a. In an exemplary embodiment, first bandpass filter 42a is a passive device that utilizes resistors, inductors, and / or capacitors to achieve bandpass filtering. In another exemplary embodiment, first bandpass filter 42a is an active device that utilizes active components (such as operational amplifiers) to achieve bandpass filtering. The center frequency of first bandpass filter 42a is within first frequency band B1, for example, at the center of first frequency band B1. First bandpass filter 42a is in electrical communication with first antenna 32a and first amplifier 40a.

[0056] The second band - pass filter 42b is used to attenuate the foreign frequency components introduced by the mixer 36. In an exemplary embodiment, the second band - pass filter 42b is a passive device that implements band - pass filtering using resistors, inductors, and / or capacitors. In another exemplary embodiment, the second band - pass filter 42b is an active device that implements band - pass filtering using active components (such as operational amplifiers). The center frequency of the second band - pass filter 42b is within the second frequency band B2, for example, at the center of the second frequency band B2. The second band - pass filter 42b is in electrical communication with the mixer output of the mixer 36 and the second amplifier 40b.

[0057] Reference Figure 4 , shows a schematic diagram of a vehicle passenger compartment with a plurality of wireless modules 16. The plurality of wireless modules 16 are located within the passenger compartment of the vehicle 12. In an exemplary embodiment, the first wireless module 16a among the plurality of wireless modules 16 is located near the front of the vehicle 12, for example, near or adjacent to the front dashboard, instrument cluster, etc. The second wireless module 16b among the plurality of wireless modules 16 is located near the passenger side of the vehicle 12, for example, near or adjacent to the rear passenger seat on the passenger side of the vehicle 12. The third wireless module 16c among the plurality of wireless modules 16 is located near the driver's side of the vehicle 12, for example, near or adjacent to the rear passenger seat on the driver's side of the vehicle 12. The fourth wireless module 16d among the plurality of wireless modules 16 is located near the rear of the vehicle 12, for example, near or adjacent to the cargo hold, trunk, third - row passenger seat, etc.

[0058] In an exemplary embodiment, the position of each of the plurality of wireless modules 16 within the passenger compartment of the vehicle 12 is determined at least in part based on the estimated sensed signal - to - noise ratio (SSNR) at one or more target locations 46 within the passenger compartment of the vehicle 12. In the scope of the present invention, the SSNR is the ratio of the power of the dynamic signal reflected from the target location 46 to the total power of the received signal. In the scope of the present invention, the target location 46 is within the passenger compartment of the vehicle 12, and it is the location where the system 10 attempts to perform occupancy detection. In a non - limiting example, one or more target locations 46 may include one or more seats of the vehicle 12, as Figure 4 shown. Although Figure 4 only one exemplary target location 46 is shown, it should be understood that the position of each of the plurality of wireless modules 16 within the passenger compartment of the vehicle 12 can be optimized based on multiple target locations, for example, based on the target locations located at each seat of the vehicle.

[0059] In an exemplary embodiment, the estimated SSNR at a given target location 46 is:

[0060]

[0061] where SSNR Tis the SSNR at the target location 46 within the passenger compartment of the vehicle 12, γ 12 is the distance (e.g., the first distance 48a) between the first of the plurality of wireless modules 16 (e.g., the first wireless module 16a) and the second of the plurality of wireless modules 16 (e.g., the second wireless module 16b). γ 1T is the distance (e.g., the second distance 48b) between the first of the plurality of wireless modules 16 (e.g., the first wireless module 16a) and the target location 46, and γ 2T is the distance (e.g., the third distance 48c) between the second of the plurality of wireless modules 16 (e.g., the second wireless module 16b) and the target location 46. It should be understood that Equation 1 can be used to estimate the SSNR at any position within or around the vehicle 12 for any pair of the plurality of wireless modules 16.

[0062] In an exemplary embodiment, during the design and / or manufacture of the vehicle 12 and the system 10, by optimizing Equation 1 to maximize the estimated SSNR value at a particular target location 46 within the passenger compartment of the vehicle 12 (e.g., as Figure 4 shown, the seat of the vehicle 12), the position of each of the plurality of wireless modules 16 within the passenger compartment of the vehicle 12 is selected. In an exemplary embodiment, placing the plurality of wireless modules 16 based on Equation 1 increases the sensitivity and accuracy of the system 10.

[0063] In an exemplary embodiment, the plurality of wireless modules 16 are mounted to the headliner, floor, frame, pillars, seat structures, and / or any additional mounting surfaces within the vehicle 12. In a non-limiting example, the plurality of wireless modules 16 are hidden by interior styling components (e.g., interior trim) of the vehicle 12. It should be understood that the foregoing description of the number and mounting manner of the plurality of wireless modules 16 is merely exemplary in nature. Variations in the number and / or mounting method or location of the plurality of wireless modules 16 do not depart from the scope of the present invention.

[0064] Referring again to Figure 1 , one or more vehicle sensors 18 are used to obtain information about the environment within the vehicle 12 (i.e., within the passenger compartment and / or the cabin of the vehicle 12). In an exemplary embodiment, the one or more vehicle sensors 18 include at least one of the following: a vehicle camera 50, a vehicle microphone 52, and a vehicle seat occupancy sensor 54.

[0065] The vehicle camera 50 is configured to capture images and / or videos of the environment inside the vehicle 12. In an exemplary embodiment, the vehicle camera 50 is a camera and / or a video camera positioned to observe the environment inside the vehicle 12. In one example, the vehicle camera 50 is fixed inside the vehicle 12, for example, fixed in the roof lining of the vehicle 12 and capable of seeing the interior of the vehicle 12. It should be understood that without departing from the scope of the present invention, the vehicle camera 50 may include a plurality of cameras disposed at multiple positions throughout the vehicle 12. It should also be understood that cameras with various sensor types, including, for example, charge-coupled device (CCD) sensors, complementary metal-oxide semiconductor (CMOS) sensors, and / or high dynamic range (HDR) sensors, are within the scope of the present invention. In addition, cameras with various lens types, such as wide-angle lenses and / or narrow-angle lenses, are also within the scope of the present invention.

[0066] The vehicle microphone 52 is configured to convert sound waves into electrical signals. In an exemplary embodiment, the vehicle microphone 52 includes a unidirectional dynamic microphone (i.e., a microphone that uses electromagnetic induction to convert sound waves into electrical signals), which is configured to receive sound from one or more specific regions inside the vehicle 12. In another exemplary embodiment, the vehicle microphone 52 includes a plurality of microelectromechanical systems (MEMS) microphones (e.g., microphones with a pressure-sensitive diaphragm directly etched into a silicon wafer) disposed throughout the interior of the vehicle 12. In another exemplary embodiment, the vehicle microphone 52 includes a directional and / or beamforming microphone that can provide data for sound source localization. It should be understood that other types of microphones configured to convert sound waves into electrical signals (e.g., digital and / or analog electrical signals) are also included in the scope of the present invention. As described above, the vehicle microphone 52 is in electrical communication with the controller 14.

[0067] The vehicle seat occupancy sensor 54 is configured to detect the presence of an occupant in a seat of the vehicle 12. In an exemplary embodiment, the vehicle seat occupancy sensor 54 includes a pressure and / or weight sensor integrated into a seat of the vehicle 12. In a non-limiting example, when an occupant sits on a seat of the vehicle 12, the controller 14 uses the pressure and / or weight sensor to detect the pressure and / or weight distribution on the seat of the vehicle 12 as a signal of the presence of the occupant. As described above, the vehicle seat occupancy sensor 54 is in electrical communication with the controller 14.

[0068] Reference Figure 5 , shows a flowchart of a method 100 for detecting one or more occupants in a vehicle. Method 100 begins at block 102 and proceeds to block 104. At block 104, the controller 14 uses at least two of the plurality of wireless modules 16 to perform a round of sensing, which will be discussed in more detail below. The result of this round of sensing is a plurality of CSI values. After block 104, method 100 proceeds to block 106.

[0069] At block 106, the controller 14 determines whether a predetermined number of sensing rounds (e.g., ten sensing rounds) have been completed. In an exemplary embodiment, the predetermined number of sensing rounds is determined by a software application running on the controller 14 that is used to request sensing. For example, a child presence detection software may request ten sensing rounds. At block 106, if the predetermined number of sensing rounds has not been completed, method 100 returns to block 104 to perform another sensing round. If the predetermined number of sensing rounds has been completed, method 100 proceeds to block 108. Thus, when proceeding to block 108, the controller 14 has recorded multiple sets of multiple CSI values, with each sensing round generating a set of multiple CSI values.

[0070] Reference Figure 6 provides a diagram showing a frequency domain graph 60 of a set of multiple CSI values for a single sensing round and a time domain graph 62 of the power delay profile for a single sensing round. The frequency domain graph 60 includes a y-axis 64a and an x-axis 64b. The y-axis 64a represents signal power level, and the x-axis 64b represents signal frequency. The time domain graph 62 includes a y-axis 66a and an x-axis 66b. The y-axis 66a represents signal power level, and the x-axis 66b represents signal delay time. Arrow 68 represents a mathematical process, such as an inverse Fourier transform, that allows the frequency domain graph 60 to be converted into the time domain graph 62.

[0071] Reference Figure 6 And continuing to refer Figure 5 to, at block 108, the controller 14 processes the multiple CSI values generated by each round of sensing. In an exemplary embodiment, as Figure 6 shown, the controller 14 performs an inverse Fourier transform on the multiple CSI values generated by each round of sensing. The result of each inverse Fourier transform is a time domain graph 62, which is referred to as the time domain power delay profile. Each time domain graph 62 contains a snapshot in time of multiple reflected signals from one round of sensing. Thus, by performing an inverse Fourier transform on the multiple CSI values generated by each round of sensing, the power variation over time of each of the multiple reflected signals can be determined.

[0072] Reference Figure 7 provides a diagram showing an exemplary time series power delay profile 70. The time series power delay profile 70 shows the power variation over time of each of the multiple reflected signals. The time series power delay profile 70 includes a y-axis 72a, an x-axis 72b, and a τ-axis 72c (τ). The y-axis 72a represents signal power level, the x-axis 72b represents time, and the τ-axis 72c represents the multiple reflected signals. For example, τ 1 is the signal power level over time of the first of the multiple reflected signals, which is determined based on the multiple time domain power delay profiles corresponding to multiple rounds of sensing. Referring again to the figure. Referring toFigure 5 , after block 108, method 100 proceeds to block 110.

[0073] At block 110, the controller 14 identifies a motion signature. In the scope of the present invention, a motion signature is a pattern among a plurality of CSI values corresponding to the motion of an occupant in the passenger compartment of the vehicle 12. In an exemplary embodiment, the motion signature includes a low-fidelity motion signature. The low-fidelity motion signature indicates the general motion or the presence of an occupant in the passenger compartment of the vehicle 12. The low-fidelity motion signature is determined by differentiating the plurality of CSI values over time, obtaining the magnitude and norm of the differentiated CSI values, and averaging the norm values over time. If the norm value exceeds a predetermined threshold, the low-fidelity motion signature is identified. The determination of the low-fidelity motion signature is discussed in more detail in a U.S. application filed on September 18, 2023, with application number 18 / 469,086 and title "SYSTEM AND METHOD FOR ACTIVATING A VOICE ASSISTANT FOR A VEHICLE", the entire content of which is incorporated herein by reference.

[0074] In another exemplary embodiment, a motion signature is identified based on an analysis of the time series power delay profile 70( Figure 7 ). In a non-limiting example, signal processing techniques such as spectrogram calculation, principal component analysis, Fourier transform, etc. are used to identify a reflected signal of interest based on signal characteristics. Referring again to Figure 7 , in a non-limiting example, the signal τ 3 exhibits a regular periodic pattern, which indicates, for example, the rise and fall of the chest of a breathing occupant in the passenger compartment of the vehicle 12. Fourier transform and / or spectrogram analysis can be used to detect periodic patterns such as breathing. It should be understood that Figure 7 the signal τ depicted in the time series power delay profile 70 of 3 is merely exemplary in nature, and the use of various additional signal processing techniques to identify any motion indicating vehicle occupancy falls within the scope of the present invention. Referring again to Figure 5 , after block 110, method 100 proceeds to block 112.

[0075] At block 112, the controller 14 determines the presence of one or more occupants in the vehicle 12 based at least in part on the motion markers identified at block 110. In an exemplary embodiment, if a low-fidelity motion marker is identified, it is determined that one or more occupants are present in the vehicle 12. In another exemplary embodiment, if the analysis of the time series power delay profile 70 identifies any motion indicative of vehicle occupancy (e.g., the breathing motion of an occupant), it is determined that one or more occupants are present in the vehicle 12. If it is determined that one or more occupants are not present in the vehicle 12, the method 100 proceeds to the standby state at block 114. If it is determined that one or more occupants are present in the vehicle 12, the method 100 advances to block 116.

[0076] At block 116, in response to determining the presence of one or more occupants in the vehicle 12, the controller 14 takes an action. In an exemplary embodiment, the action is determined at least in part based on a software application running on the controller 14 that requests activation of the system 10. In a non-limiting example, the child presence detection software can take an action by providing visual, audible, and / or tactile notifications and / or visual, audible, and / or tactile warnings to the driver and / or occupants of the vehicle 12 informing them of the presence of an additional occupant (e.g., a child) in the vehicle. After block 116, the method 100 proceeds to the standby state at block 114.

[0077] In an exemplary embodiment, the controller 14 repeatedly exits the standby state 114 and restarts the method 100 at block 102. In a non-limiting example, the controller 14 exits the standby state 114 and restarts the method 100 on a timer, e.g., every three hundred milliseconds.

[0078] Reference Figure 8 , shows a flowchart of an exemplary embodiment 104a of block 104 (i.e., a method for performing a round of sensing). Exemplary embodiment 104a begins at block 802. At block 802, the controller 14 performs one or more measurements using one or more vehicle sensors 18. In an exemplary embodiment, the one or more measurements include one or more images and / or videos of the passenger compartment of the vehicle 12 captured by the vehicle camera 50. In another exemplary embodiment, the one or more measurements include one or more sound measurements captured by the vehicle microphone 52. In another exemplary embodiment, the one or more measurement results include one or more weight and / or pressure measurements performed by the vehicle seat occupancy sensor 54. After block 802, exemplary embodiment 104a proceeds to block 804.

[0079] At block 804, the controller 14 determines a predicted position of one or more occupants within the passenger compartment of the vehicle 12 based at least in part on one or more measurements performed at block 802. In an exemplary embodiment, the controller 14 uses a computer vision algorithm to segment and classify one or more images and / or videos of the passenger compartment to identify the predicted position of the occupants. In another exemplary embodiment, the controller 14 analyzes one or more sound measurements to determine the predicted position of the occupants based on data from directional and / or beamforming microphones. In another exemplary embodiment, the controller 14 determines the predicted position based on one or more weight and / or pressure measurements of one or more seats in the vehicle 12. After block 804, exemplary embodiment 104a proceeds to block 806.

[0080] At block 806, the controller 14 determines a plurality of participating wireless modules based at least in part on the predicted position determined at block 804. In an exemplary embodiment, the plurality of participating wireless modules is a subset of the plurality of wireless modules 16. The plurality of participating wireless modules includes at least two of the plurality of wireless modules 16. In an exemplary embodiment, the plurality of participating wireless modules is determined based on the estimated SSNR at the predicted position, where the estimated SSNR at the predicted position is determined based on Equation 1. In a non-limiting example, the plurality of participating wireless modules includes any two (a pair) of the plurality of wireless modules 16, where Equation 1 predicts that the SSNR between the pair of wireless modules at a predetermined position is greater than or equal to a predetermined SSNR threshold.

[0081] Referring again to Figure 4 , an exemplary selection of the plurality of participating wireless modules is discussed. It should be understood that the process for the following exemplary selection of the participating wireless modules is merely exemplary in nature and the assumptions made for the sake of example are not intended to limit the scope of the present invention. For purposes of illustration, assume that the predicted position is located at the target position 46. For purposes of example, it is also assumed that for communication between the first wireless module 16a and the second wireless module 16b at the target position 46, the normalized exemplary estimated SSNR given by Equation 1 is 1. For purposes of example, it is also assumed that for communication between the first wireless module 16a and the third wireless module 16c at the target position 46, Equation 1 gives a normalized exemplary estimated SSNR of 0.7. For purposes of example, it is also assumed that for communication between the second wireless module 16b and the fourth wireless module 16d at the target position 46, the normalized exemplary estimated SSNR given by Equation 1 is 0.4. For purposes of example, it is also assumed that the predetermined SSNR threshold is 0.5. Thus, in the foregoing example scenario, the plurality of participating wireless modules includes the first wireless module 16a, the second wireless module 16b, and the third wireless module 16c.

[0082] It should be understood that the foregoing scenarios are merely exemplary in nature. It should also be understood that the controller 14 can utilize any algorithm, logic, or method to determine a plurality of participating wireless modules based on the estimated SSNR at the predicted location. In a non-limiting example, the controller 14 uses, for example, a lookup table to store information about pairs of wireless modules among the plurality of wireless modules 16 that provide a high estimated SSNR at a plurality of predetermined target locations.

[0083] In an exemplary embodiment, it is desirable to reduce the number of participating wireless modules to reduce the time required for each round of sensing and increase the overall sensing frequency of the system 10. In some embodiments, the controller 14 can adopt a "round-robin" strategy, incorporating different subsets of the plurality of wireless modules 16 into the plurality of participating wireless modules during each round of sensing. In some embodiments, the controller 14 incorporates all of the plurality of wireless modules 16 into the plurality of participating wireless modules during each round of sensing.

[0084] In addition, the controller 14 can adjust the plurality of participating wireless modules based on the hardware capabilities of each of the plurality of wireless modules 16 (e.g., available transmit and receive channels and frequency bands). For example, the signal conversion device 24b may only receive and retransmit the received signal and not generate a new signal. After block 806, the exemplary embodiment 104a proceeds to block 808.

[0085] At block 808, the controller 14 determines the transmission characteristics of transmitting one or more signals between each of the plurality of participating wireless modules. Within the scope of the present invention, the transmission characteristics include, for example, the transmission frequency band and the transmission channel. In an exemplary embodiment, the frequency band is determined based on the hardware capabilities of each of the plurality of wireless modules 16. In an exemplary embodiment, the controller 14 changes the frequency band and / or the transmission channel of one or more signals between at least two of one or more rounds of sensing. For example, the first round of one or more rounds of sensing may utilize the 2.4 GHz frequency band, while the second round of one or more rounds of sensing utilizes the 5 GHz frequency band. In a non-limiting example, a Channel Switch Announcement (CSA) message is used to switch the frequency band and / or the transmission channel. In an exemplary embodiment, changing the frequency band and / or the transmission channel is advantageous because each frequency band and channel combination provides additional bandwidth for sensing, thereby increasing the sensing resolution of the system 10. After block 808, the exemplary embodiment 104a proceeds to block 810.

[0086] At block 810, the controller 14 transmits one or more signals between each combination (i.e., each possible module pair) consisting of two of the plurality of participating wireless modules. In an exemplary embodiment, the one or more signals are original training signals (i.e., known signals transmitted for the purpose of CSI value estimation).

[0087] In an exemplary embodiment, for each pair of a plurality of participating wireless modules, one participating wireless module in the pair transmits an original training signal, and the other participating wireless module in the pair receives the propagated training signal. In another exemplary embodiment using the digital WLAN transceiver system 24a and the signal conversion device 24b, the digital WLAN transceiver system 24a transmits the original training signal; the signal conversion device 24b receives the original training signal, converts it to another frequency band (e.g., the second frequency band B2), and re-transmits them back to the digital WLAN transceiver system 24a. In an exemplary embodiment, for each pair of a plurality of participating wireless modules, the original training signal is transmitted between a pair of participating wireless modules at a time to mitigate interference and / or crosstalk between multiple pairs of participating wireless modules. In another exemplary embodiment, different frequency bands (e.g., orthogonal frequency bands) are used to transmit the original training signals between all pairs of a plurality of participating wireless modules simultaneously.

[0088] Due to the combined effects such as scattering, fading, and power attenuation caused by objects (e.g., passengers) in the passenger compartment of the vehicle 12, the received signal is different from the original signal and is referred to as the propagated training signal. After block 810, exemplary embodiment 104a proceeds to block 812.

[0089] At block 812, the controller 14 determines a plurality of CSI values based at least in part on one or more signals transmitted at block 810. In an exemplary embodiment, the plurality of CSI values are determined based at least in part on the deviation between the original training signal and the propagated training signal. After block 812, exemplary embodiment 104a ends, and method 100 continues as described above.

[0090] The system 10 and method 100 of the present invention provide several advantages. By optimizing the positions of the plurality of wireless modules 16 based on Equation 1, the accuracy of the system 10 in detecting motion at the position of interest is improved. In addition, by predicting the position and adjusting the plurality of participating wireless modules based on the estimated SSNR provided by Equation 1, the system 10 can dynamically adjust the sensing accuracy and frequency based on the predicted position of the occupant.

[0091] The description of the present invention is merely exemplary in nature, and variations that do not depart from the gist of the present invention are intended to fall within the scope of the present invention. These variations should not be regarded as departing from the spirit and scope of the present invention.

Claims

1. A system for detecting one or more occupants in a vehicle, the system comprising: Multiple wireless modules; a controller in electrical communication with the plurality of wireless modules, wherein the controller is programmed to: performing one or more rounds of sensing, wherein each round of the one or more rounds of sensing includes communication between at least two of the plurality of wireless modules; as well as The presence of the one or more occupants in the vehicle is determined based at least in part on the one or more wheel sensing.

2. The system of claim 1, wherein to perform one or more rounds of sensing, the controller is further programmed to: determining a plurality of participating wireless modules, wherein the plurality of participating wireless modules is a subset of the plurality of wireless modules, and wherein the plurality of participating wireless modules includes at least two of the plurality of wireless modules; transmitting one or more signals between at least two of the plurality of participating wireless modules; and A plurality of channel state information (CSI) values ​​are determined based at least in part on the one or more signals.

3. The system of claim 2, wherein for said determining a plurality of participating wireless modules, said controller is further programmed to: determining a predicted position of the one or more occupants within a passenger compartment of the vehicle; and The plurality of participating wireless modules is determined based at least in part on predicted locations of the one or more occupants within a passenger compartment of the vehicle.

4. The system of claim 3, further comprising one or more vehicle sensors in electrical communication with the controller, wherein to said determining the predicted position of the one or more occupants within the passenger compartment of the vehicle, the controller is further programmed to: performing one or more measurements using the one or more vehicle sensors; and A predicted position of the one or more occupants within a passenger compartment of the vehicle is determined based at least in part on the one or more measurements.

5. The system of claim 2, wherein to transmit one or more signals between at least two of the plurality of participating wireless modules, the controller is further programmed to: The one or more signals are transmitted between each combination of two of the plurality of participating wireless modules.

6. The system of claim 2, wherein to transmit one or more signals between at least two of the plurality of participating wireless modules, the controller is further programmed to: A frequency band of the one or more signals is changed between at least two of the one or more rounds of sensing.

7. The system of claim 2, wherein to determine the presence of the one or more occupants in the vehicle, the controller is further programmed to: performing an inverse Fourier transform on the plurality of CSI values ​​to determine a time domain power delay profile; identifying a motion marker based at least in part on the time-domain power delay profile; and The presence of the one or more occupants in the vehicle is determined based at least in part on the motion signature.

8. The system according to claim 1, wherein one or more of the plurality of wireless modules is at least one of: a digital wireless local area network (WLAN) transceiver system, the WLAN transceiver system being configured to implement a wireless communication protocol; and a signal conversion device, the signal conversion device being configured to convert signals between at least two frequency bands.

9. The system of claim 8, wherein one or more of the plurality of wireless modules are located within a passenger compartment of the vehicle, and wherein the location of each of the plurality of wireless modules is determined at least in part based on an estimated sensed signal-to-noise ratio (SSNR) at one or more target locations within the passenger compartment of the vehicle.

10. The system of claim 9, wherein the SSNR at a target location within a passenger compartment of the vehicle is defined as: in, SSNR T is the SSNR at the target location within the passenger compartment of the vehicle, γ 12 is the distance between the first wireless module among the plurality of wireless modules and the second wireless module among the plurality of wireless modules, γ 1T is the distance between the first wireless module of the plurality of wireless modules and the target location, and γ 2T is the distance between a second wireless module among the multiple wireless modules and the target location.

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