Seat occupancy sensor system for vehicles and method of using the same

Abstract

To offer improved accuracy and / or performance, in a seat occupancy sensor system and method, which use radio frequency (RF) sensors to detect and distinguish vehicle occupants in a passenger cabin of a vehicle.SOLUTION: A system provided herein includes one or more seat occupancy sensors and a seat occupancy control module, and can operate in different operational modes depending on the state of vehicle doors. When one or more doors are open, the system operates in a first operational mode that keeps track of vehicle occupants entering and / or exiting the passenger cabin and, when no doors are open, the system operates in a second operational mode that detects and distinguishes vehicle occupants in the passenger cabin using the occupant count from the first mode as an input.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates generally to sensor systems for vehicles, and more particularly to seat occupancy sensor systems that use radio frequency (RF) sensors. [Background technology]

[0002] Various types of sensors have been used in vehicles to determine the occupancy status of the front and / or rear seats. For example, pressure sensors, capacitance sensors, and ultrasonic sensors have all been used, but each of these different sensor types has certain drawbacks. While pressure and capacitance sensors can detect and distinguish seat occupancy, systems using such sensors can be expensive because a separate sensor is required for each seat. On the other hand, a single ultrasonic sensor can detect movement in and around multiple seats, but may not have the resolution to accurately distinguish between occupants, especially when occupants are seated very close to each other or in the second or third row of a vehicle. Summary of the Invention

[0003] According to one aspect, an exemplary embodiment of a seat occupancy sensor system for a vehicle is provided, the embodiment comprising: at least one seat occupancy sensor configured to receive radio frequency (RF) signals within a passenger compartment of the vehicle; and a seat occupancy control module in communication with the seat occupancy sensor, the seat occupancy control module configured to operate the seat occupancy sensor system in first and second operating modes, wherein when at least one vehicle door is open, the seat occupancy control module is configured to operate the seat occupancy sensor system according to a first operating mode that tracks vehicle occupants entering and exiting the passenger compartment using occupant counting; and when no vehicle door is open, the seat occupancy control module is configured to operate the seat occupancy sensor system according to a second operating mode that detects and distinguishes vehicle occupants within the passenger compartment, the occupant counting from the first operating mode being used as an input to the second operating mode.

[0004] According to another aspect, an exemplary embodiment of a method of using a seat occupancy sensor system for a vehicle is provided, the system comprising at least one seat occupancy sensor configured to receive radio frequency (RF) signals within a passenger compartment of the vehicle and a seat occupancy control module in communication with the seat occupancy sensor, the method including: receiving, at the seat occupancy control module, a door status signal indicative of a status of one or more vehicle doors; selecting, with the seat occupancy control module, a first operational mode or a second operational mode based at least in part on the status of the vehicle doors; operating the seat occupancy sensor system according to the first operational mode by tracking vehicle occupants entering and exiting the passenger compartment using occupant counts when the at least one vehicle door is open; and operating the seat occupancy sensor system according to the second operational mode by detecting and distinguishing vehicle occupants within the passenger compartment when the vehicle door is not open, wherein the occupant counts from the first operational mode are used as input to the second operational mode.

[0005] It is contemplated that any number of the individual features of the above-described embodiments and any other embodiments shown in the drawings or description below may be combined in any combination to define the invention, except where the features are incompatible. [Brief explanation of the drawings]

[0006] Exemplary embodiments are described with reference to the following drawings, in which like numbers refer to like elements and in which: [Figure 1] 1 is a schematic diagram illustrating an example of a seat occupancy sensor system installed within a passenger compartment of a vehicle. [Figure 2] FIG. 2 is a schematic block diagram of the seat occupancy sensor system of FIG. 1; [Figure 3] 2 is a flowchart illustrating an example of a method of using a seat occupancy sensor system such as the seat occupancy sensor system of FIG. 1 . DETAILED DESCRIPTION OF THE INVENTION

[0007] A seat occupancy sensor system and method are described that uses radio frequency (RF) sensors to detect and distinguish vehicle occupants within a vehicle passenger compartment. The system and method may be used with any type of vehicle, including any type of car, truck, sports utility vehicle (SUV), off-road vehicle (ORV), crossover vehicle, commercial vehicle, etc., including those powered by a traditional internal combustion engine, an electric motor, or a hybrid powertrain having both, to name a few possibilities. The output of the system and method may be provided to and used by any number of different vehicle systems and / or modules, such as a seat belt warning system, an airbag deployment system, a collision avoidance system, a safety system, an infotainment system, etc.

[0008] Referring now to FIG. 1 , a schematic diagram of a seat occupancy sensor system 10 installed within a passenger compartment 12 of a vehicle 14 is shown. According to one example, the seat occupancy sensor system 10 is a multiple-input multiple-output (MIMO), frequency modulated continuous wave (FMCW), millimeter-wave radio detection and ranging (RADAR) system. The seat occupancy sensor system 10 may include one or more seat occupancy sensors 20, 22 strategically mounted throughout the passenger compartment 12 and a seat occupancy control module 30 in communication with the sensors. The seat occupancy sensor system and method may strategically operate according to different operating modes based on the state or status of the vehicle doors. When one or more doors are open, the system and method may operate according to a first operating mode that uses RF signals to track vehicle occupants entering and exiting the passenger compartment. When the door is not open (and possibly when the vehicle is being driven), the seat occupancy sensor system and method can operate according to a second mode of operation that uses RF signals to detect and distinguish vehicle occupants within the passenger compartment, with the occupant count from the first mode being used as an input to the second mode. These different modes of operation can help improve the accuracy and / or performance of the seat occupancy sensor system 10, especially when occupants are seated very close to each other, when occupants are seated in the second or third row, when occupants are seated in the middle seat, and / or when occupants are leaning or stretched out in adjacent seats (all of which can make accurate occupant sensing difficult).

[0009] The seat occupancy sensors 20, 22 are mounted at strategic locations within the passenger compartment 12 and use radio frequency (RF) signals to detect objects and / or motion within the passenger compartment. For example, the seat occupancy sensor 20 may be mounted on or near the A-pillar 40 or roof panel 50 and pointed toward the driver's seat 42 and / or passenger seat 44 to detect objects and / or motion within the space associated with these seats. If object motion is detected by the sensor 20, the seat occupancy sensor system 10 may conclude that a vehicle occupant is seated in one or both of the front seats. On the other hand, the seat occupancy sensor 22 may be mounted on or near the B-pillar 46, C-pillar 48, or roof panel 50 and oriented toward the second row to sense occupants seated in the rear driver's seat 52, rear passenger seat 54, and / or rear center seat 56. Thus, a single seat occupancy sensor 20, 22 may be used to detect and distinguish between multiple occupants. It should be pointed out that the present system and method are not limited to the exemplary embodiment schematically shown in FIG. 1 , and therefore any number and / or arrangement of seat occupancy sensors may be used. For example, fewer than two seat occupancy sensors may be used, or additional sensors may be employed; instead of only sensors 20, 22 being mounted on the driver's side, sensors may be mounted on both the driver's and passenger's sides (e.g., four sensors total). Instead of only two rows, the vehicle may have three rows with one or two sensors per row (e.g., three or six sensors total). Alternatively, in addition to or instead of the side-mounted sensors 20, 22, there may be one or more centrally mounted sensors installed on the dashboard, rearview mirror assembly, interior lights, roof panel, etc. Rather than all of the seat occupancy sensors being mounted along the perimeter of the passenger compartment 12 as shown, one or more sensors may be mounted inside the passenger compartment, such as behind the headrests 60, 62 or near the rear window. The foregoing examples represent only some of the possible sensor arrangements that may be utilized by the present system and method; others may be used as well.

[0010] The seat occupancy sensors 20, 22 may be active sensors that actively emit electromagnetic signals in the RF frequency range (approximately 20 kHz to 300 GHz), receive reflected signals bouncing off various objects, and analyze the reflected signals according to radio detection and ranging (RADAR) techniques to determine the presence of occupants in various seats. As active RADAR sensors, the seat occupancy sensors 20, 22 may include a transmitter, receiver, and antenna, all integrated into the same unit or device, sometimes referred to as a monostatic RADAR device. The seat occupancy sensors 20, 22 may be configurable such that the present systems and methods (e.g., the seat occupancy control module 30) can control or adjust certain settings, such as distance resolution, velocity resolution, and / or angular resolution, as described in more detail below.

[0011] In different embodiments, the seat occupancy sensors 20, 22 may be passive RADAR sensors that do not actively emit RF signals but instead passively listen for reflected RF signals emitted by different sources. For example, the seat occupancy sensors 20, 22 may listen for reflected WiFi signals (2-5 GHz), Bluetooth signals (2.4 GHz), and / or other RF signals already present within the passenger compartment 12. If the vehicle 14 has an infotainment system 66 that already transmits RF signals throughout the passenger compartment 12 (e.g., at a frequency of approximately 5 GHz), the seat occupancy sensors 20, 22 may be positioned and configured to passively listen for and analyze reflected signals or echoes of these signals to determine the presence of occupants in different seats. This constitutes a passive sensor system. A passive sensor system with transmitters and receivers in different locations is sometimes referred to as a bistatic RADAR device. The seat occupancy sensor system 10 may also include a combination of active and passive RADAR or RF sensors, as well as other types of sensors.

[0012] The seat occupancy control module 30 is an electronic module that communicates with the sensors 20, 22 and can be designed to control or manage specific aspects of their operation. Modern vehicles typically have a large and diverse collection of such electronic modules, the exact configuration of which depends on the nature and sophistication of the vehicle. The electronic modules, also referred to as electronic control units, electronic controllers, or simply controllers, have embedded software for performing their prescribed tasks or functions and are connected to numerous other electronic devices throughout the vehicle via some type of wired or wireless internal communication network (e.g., a vehicle bus). The vehicle 14 can include any suitable combination or arrangement of electronic modules and / or communication networks and is not limited to the specific embodiment shown schematically in FIG. 1 or described herein, but can include any suitable combination of a body control module 70, a seat belt warning system 72, and other components, devices, units, modules, controllers, and / or systems known in the art. The modules and systems described herein may be stand-alone units or may be integrated or combined with other modules and systems. According to one non-limiting example, the seat occupancy control module 30 includes an application manager unit 100, a vehicle interface unit 110, a signal processing unit 120, and a decision unit 130, as shown in Figure 2 and further described below. It should be noted that the one or more seat occupancy control modules 30 may be integrated or combined with one or more seat occupancy sensors 20, 22 (e.g., where each sensor has its own integrated control module), or may be separate units.

[0013] The body control module (BCM) 70 is configured to monitor and control certain functions associated with the vehicle body, such as doors, door locks, windows, and lights. According to one embodiment, the BCM 70 is connected to the seat occupancy control module 30 via an internal communication network, such as a vehicle bus, to monitor and report the status of each of the vehicle's doors. That is, the BCM 70 can receive signals from one or more door sensors operably coupled to each door and determine whether each door is open or closed. The BCM 70 can then provide the seat occupancy control module 30 with door status signals indicative of the state or status of one or more of the vehicle doors, thereby indicating whether such door is open or closed. Because door sensors can monitor the status of different vehicle doors and can be connected (directly or indirectly) to the internal communication network to provide door status signals, etc., to the present systems and methods, the BCM 70 need not transmit door status signals.

[0014] The seat belt warning system 72 is configured to monitor and control certain safety features, such as those related to seat belts and their status. In one example, the seat belt warning system 72 generates alerts or warnings to the driver or other vehicle occupants, as well as other modules and / or systems within the vehicle. For example, if one or more vehicle occupants are detected but are not wearing their seat belts, the seat belt warning system 72 may generate an audible and / or visual warning requesting that the occupants wear their seat belts, or may send a seat belt status signal indicating the occupants' seat belt status to other systems within the vehicle, such as an airbag deployment system.

[0015] 2 and 3, a schematic block diagram of a method 200 for using the seat occupancy control module 30 and the seat occupancy sensor system 10 is shown. The method 200 can begin at different times, including when triggered by one of several trigger events, such as a vehicle door being opened (step 210). For example, when a vehicle door is opened, the body control module (BCM) 70 or other electronic module or device may send a door status signal to the seat occupancy control module 30 indicating that the vehicle door has been opened. The seat occupancy control module 30 can include a vehicle interface unit 110 having a door event detection application 150 that receives and processes the door status signal, which can later send a corresponding signal to the application manager unit 100. The vehicle interface unit 110 can also include a belt buckle event detection application 152, a vehicle state detection application 154, and / or an occupancy status reporting application 156.

[0016] In response to a vehicle door being opened, the method may initiate a first mode of operation (step 220) to track and count the number of occupants entering and exiting the passenger compartment. Tracking occupants within a vehicle may provide useful data points and therefore improve the accuracy of the present system and method. To accurately track and count occupants as they enter and exit the vehicle, step 220 may require modifying or adjusting certain settings of the seat occupancy sensors 20, 22, such as the range resolution, velocity resolution, and / or angular resolution. Those skilled in the art will understand that optimizing certain settings of a RADAR or RF sensor will improve some performance characteristics while adversely affecting other performance characteristics. Because the first mode of operation is designed to track and count occupants (i.e., moving targets) as they enter and exit the vehicle, it may be advantageous for the first mode of operation to optimize the velocity resolution of the seat occupancy sensors 20, 22. Increasing the velocity resolution of the sensors allows the first mode of operation to better distinguish moving targets based on their movement and / or velocity, thereby improving the accuracy of occupant counting as people enter and exit the vehicle. However, this optimization of velocity resolution is not achieved without a trade-off, as the range and / or angular resolution of the seat occupancy sensors 20, 22 may be somewhat affected. The seat occupancy control module 30 may include an application manager unit 100 having a mode manager application 140 that selects an appropriate operating mode based on input from the vehicle interface unit 110, and a signal processing mode selector application 142 that adjusts or modifies certain parameters based on the selected operating mode, as described below.

[0017] Possible ways for step 220 to increase velocity resolution during the first mode of operation include adjusting the configuration of chirp parameters and / or implementing signal processing techniques used with the seat occupancy sensors 20, 22. As used herein, the term "chirp" or "chirp signal" broadly includes any RADAR or RF signal whose frequency increases ("up-chirp") or decreases ("down-chirp") over time. The chirp start frequency is the frequency at which the chirp begins, the chirp end frequency is the frequency at which the chirp ends, the chirp bandwidth is the range of frequencies of the chirp signal (typically the frequency delta between the chirp start and chirp end frequencies), the chirp duration is the duration of the chirp signal (typically the time delta between the chirp start and chirp end frequencies), and the chirp rate is the rate at which the chirp frequency changes (typically chirp bandwidth / chirp duration). Increasing the chirp duration in the first operating mode (e.g., to about 10-100 μs) can enable finer resolution of the Doppler frequency, which in turn increases the accuracy or precision of velocity measurements for moving targets. Furthermore, providing stable chirp generation helps ensure that the chirp signal is stable over the chirp duration, as instability in the chirp signal can reduce the accuracy of the Doppler measurement and therefore the precision of velocity measurements for moving targets, such as occupants entering or exiting a vehicle.

[0018] While the foregoing examples illustrate different ways in which the first operating mode can increase velocity resolution by manipulating different chirp parameters, the first operating mode can also improve velocity resolution by implementing different signal processing techniques. For example, step 220 can improve the velocity resolution of the seat occupancy sensors 20, 22 by performing a fast Fourier transform (FFT) on the reflected RADAR or RF signals or echoes to better identify Doppler frequency shifts corresponding to velocity measurements of moving targets. Another signal processing technique that can be optimized by the first operating mode in step 220 relates to FFT size. Increasing the FFT size allows for finer frequency resolution in the Doppler domain, which in turn results in better velocity resolution. Yet another possible signal processing technique that can be optimized in step 220 relates to the application of window functions (e.g., Hamming, Hanning, or Blackman windows) in Doppler processing to reduce spectral leakage. The foregoing examples are signal processing techniques that can be employed by the present system and method to enhance or improve the velocity resolution of the system during the first operating mode, when occupants are most likely to enter or exit the vehicle. Other signal processing techniques may be used as well. The selection of the operating mode and / or the optimization of the velocity resolution performed in step 220 may be performed by a command signal sent from an application manager unit 100, such as a mode manager application 140 and / or a signal processing mode selector application 142, to a signal processing unit 120, such as a counting and tracking signal processing 1 application 160 or an ML data quality improvement application 164. It is also possible that the selection of the operating mode and / or the optimization of the velocity resolution may be performed within and / or by the sensors 20, 22.

[0019] Having made one or more adjustments or modifications to the chirp parameters and / or signal processing techniques to improve the velocity resolution of the seat occupancy sensors 20, 22, step 230 counts and tracks occupants entering and exiting the vehicle according to the first mode of operation. Occupant counting and tracking can be performed in any number of different ways, all of which use some type of occupant counting. For example, step 230 may simply monitor all of the vehicle doors, tracking the total number of occupants in the vehicle 14 at any given time and providing a corresponding occupant count representative of the total number of occupants in the vehicle; may monitor all or a portion of the vehicle doors, tracking the total number of occupants in each row of the vehicle and providing one or more occupant counts each representative of the total number of occupants in each row; may monitor a particular vehicle door, tracking occupants in each seat and providing one or more occupant counts each representative of a seat that is believed to be occupied; or may provide multiple occupant counts (e.g., an occupant count for the total number of occupants in the vehicle and an occupant count for each row and / or seat) using some combination of the foregoing or other examples. The occupancy counts may be a sum, a net value, a probability value, a binary value, or some other type of value or quantity. Each of these occupant counts may be a useful data point for the second mode of operation and may provide clues as to the actual occupant seating situation, as described below.

[0020] As long as one or more vehicle doors remain open, the method may track occupants entering or exiting the vehicle (step 240). Door status signals provided by the body control module (BCM) 70 or some other sensor, device, and / or module may be used by step 240 to make this determination. Depending on the embodiment, step 240 may also use other factors or inputs to determine when to proceed. For example, step 240 may verify that all of the vehicle doors are closed, as well as that the vehicle is "in motion" or moving, before proceeding to the next step. The seat occupancy control module 30 may utilize the door event detection application 150 and / or the vehicle state detection application 154 in the vehicle interface unit 110 to make the determination in step 240 and send a corresponding signal to the application manager unit 100.

[0021] Next, step 250 initiates a second operational mode that detects and distinguishes vehicle occupants within the passenger compartment and uses the occupant counts from the first operational mode as input. Step 220 may need to modify or adjust certain settings of the seat occupancy sensors 20, 22, such as the range resolution, velocity resolution, and / or angular resolution, to produce accurate results. Previously, this method optimized the velocity resolution of the system in the first operational mode to better detect occupants entering or exiting the vehicle (i.e., moving targets). Here, it is assumed that all vehicle doors are closed and the vehicle 14 is in motion, so the occupants may be seated very close to each other while remaining mostly stationary or moving only minimally in each of their seats. In these conditions, velocity resolution is less critical to the performance of the seat occupancy sensor system 10 than range resolution and / or angular resolution. Therefore, step 250 can increase the range resolution and / or angular resolution during the second operational mode by adjusting chirp parameters and / or signal processing techniques associated with the seat occupancy sensors 20, 22.

[0022] In one example, step 250 increases or optimizes range resolution by increasing the chirp bandwidth (sometimes referred to as the “sweep bandwidth”) of the RF signal. Those skilled in the art will understand that the range resolution of most FMCW radar systems is proportional to the chirp bandwidth. Therefore, increasing the chirp bandwidth can increase the system's range resolution, which can be important during the second mode of operation, where occupants are typically stationary and may be seated close together. If the range resolution is not high enough, two occupants seated close together may be erroneously interpreted as a single target. In another example, step 250 may increase range resolution by increasing the chirp rate (e.g., by increasing the frequency slope of the chirp) to ensure that the seat occupancy sensor system 30 can effectively process wider chirp bandwidths. With regard to optimizing angular resolution through manipulation of chirp parameters, step 250 may ensure stable and consistent chirp generation (e.g., frequency stability, phase stability, amplitude stability, frequency modulation linearity time, etc.), as this can positively impact the quality of data used during signal processing algorithms such as those associated with beamforming.

[0023] While the foregoing examples illustrate different ways in which the second operating mode can increase range and / or angular resolution by manipulating different chirp parameters, the second operating mode can also improve range and / or angular resolution by implementing different signal processing techniques. For example, step 250 can implement pulse compression techniques to improve the range resolution of the seat occupancy sensors 20, 22 by better utilizing the increased chirp bandwidth. This is because pulse compression typically improves the signal-to-noise ratio (SNR) of the received RF signal. This, in turn, allows for better discrimination of targets in terms of range, which can be useful when trying to distinguish between different occupants seated very close to one another. Step 250 may also apply a window function (e.g., a Hamming window, a Hanning window, or a Blackman window) to the received RF signal before performing the FFT, which can reduce sidelobes and improve resolution. Another example of a signal processing technique that can be utilized in step 250 to optimize range resolution involves manipulating the size of the FFT. Using a larger FFT size during range processing can provide finer resolution in the frequency domain, which results in greater range resolution.

[0024] There are also signal processing techniques that can be implemented or applied in step 250 to optimize angular resolution, which can provide a more accurate spatial representation of the passenger cabin and enable improved occupant location and / or identification. One such signal processing technique is digital beamforming, which can be well suited to detecting and / or distinguishing between slowly moving or stationary targets (e.g., occupants seated in seats) who may be seated close together or whose arms or legs may be obscured by adjacent seats. Digital beamforming, particularly in the context of MIMO FMCW millimeter-wave RADAR systems, involves the use of multiple transmit antennas and multiple receive antennas (e.g., seat occupancy sensors 20, 22, and others) that are focused in specific directions (e.g., azimuth and / or elevation). Implementing beamforming techniques in step 250 can help enable the present systems and methods to precisely control beam direction and enhance angular resolution. In one example, step 250 uses digital beamforming techniques to focus or direct the seat occupancy sensors 20, 22 toward an area or space within the passenger cabin corresponding to a particular seat (the system has knowledge of the interior layout or geometry of the passenger cabin). A single seat occupancy sensor 20, 22 can potentially monitor multiple seats, with the sensor directed toward the boundary between adjacent seats being monitored, the center of the particular seat being monitored, or a different target. Other beamforming and / or signal processing techniques could certainly be applied and implemented as well.

[0025] The foregoing examples are signal processing techniques that may be employed by the present system and method to enhance or improve the range and / or angular resolution of the system during the second mode of operation, in which passengers are most likely seated in different seats in the cabin. Other signal processing techniques may be used as well. The selection of the operating mode and / or optimization of the range and / or angular resolution performed in step 250 may be performed by command signals sent from the application manager unit 100, such as the mode manager application 140 and / or the signal processing mode selector application 142, to the signal processing unit 120.

[0026] Next, step 260 detects and distinguishes occupants within the passenger compartment according to a second operating mode, sometimes referred to as a “localization mode.” According to one example, the seat occupancy sensors 20, 22 use RF or RADAR signals to evaluate moving points (also called cloud points) located within a specific three-dimensional (3D) space corresponding to one or more passenger seats within the passenger compartment. When the number of cloud points for a specific 3D space exceeds a specific threshold, the seat occupancy sensor system and method can determine that the corresponding passenger seat is occupied. As explained above, the second operating mode, or localization mode, is designed to optimize the range and / or angular resolution of the system when all of the vehicle doors are closed and occupants are likely seated in their seats (e.g., when the vehicle is being driven). This optimization, which may come at the expense of velocity resolution, improves the accuracy of the localization mode in step 260, but it may still be difficult to distinguish one nearby occupant from another, especially if the occupants are not moving much.

[0027] Thus, step 260 takes into account and / or otherwise considers the occupant count from the first mode of operation as input to the second mode of operation. In one example, step 260 first determines the number and location of occupants in the passenger compartment according to the second mode of operation and then matches that information with the occupant count from the first mode of operation. If the occupant count verifies or confirms the findings from the location mode, whether vehicle-based, row-based, and / or seat-based, step 270 may conclude that the method has accurately detected and identified one or more vehicle occupants in the passenger compartment and transfer control to step 280. On the other hand, if the occupant count does not confirm the findings of the location mode (e.g., if the vehicle-based, row-based, and / or seat-based occupant counts indicate different occupant counts), step 270 may transfer control back to step 260 to repeat that step using the same parameters and techniques of the second mode of operation previously used. In a different example where the occupant count does not match the findings of the location mode, step 270 may return control of the method to step 250 so that some of the parameters and / or techniques of the second operating mode may be modified or adjusted before proceeding to step 260 and repeating that step. Using both the first and second operating modes cooperatively can have the desirable effect of reducing false positives or negatives (i.e., detecting an occupant when one is not actually present) as well as reducing missed or positive detections (i.e., not detecting an occupant when one is actually present). Other examples are certainly possible, and the foregoing examples are merely some of the possibilities for how the occupant count from the first operating mode may be used as input to the second operating mode. The occupant detection and discrimination, as well as the corroboration of the outputs of the two different operating modes performed in step 260, may be performed by signal processing unit 120 (e.g., location signal processing application 162) and / or determination unit 130 (e.g., ML location determination application 170 and / or RB location determination application 172).It is also possible that one or more units within seat occupancy control module 30 use machine learning and / or artificial intelligence (AI) driven algorithms, rule-based algorithms, and / or a combination of both to perform these steps. Output from these applications may be returned to application manager unit 100 and / or vehicle interface unit 110, for example.

[0028] Once the outputs of the first and second operating modes confirm or corroborate each other, the method proceeds to step 280 and transmits the occupant status to one or more devices, units, modules, and / or systems within the vehicle. The occupant status output, according to one example, represents the occupancy status of each seat within the vehicle (e.g., a binary indication of occupancy for each seat (yes / no), a probability indication of occupancy for each seat, or some other type of occupancy indication) and can be transmitted to any number of different destinations within and / or outside the vehicle, such as a seat belt warning system, an airbag deployment system, a collision avoidance system, a safety system, an infotainment system, etc. The present system and method are not limited in how the occupancy status output may be used.

[0029] In different embodiments, method 200 may be modified such that occupant counting and tracking according to a first mode of operation (steps 220, 230) and / or occupant detection and differentiation according to a second mode of operation (steps 250, 260) may be performed whenever the seat belt status changes for one or more occupants. This may also be true when a vehicle door remains closed and / or open, as a change in seat belt status can serve as a trigger event.

[0030] It should be understood that the above is a description of one or more embodiments of the present invention. The present invention is not limited to the specific embodiment(s) disclosed herein, but rather is defined solely by the claims that follow. Furthermore, the statements contained in the above description relate to specific embodiments and should not be construed as limitations on the scope of the invention or the definition of terms used in the claims, unless a term or phrase is expressly defined above. Various other embodiments, as well as various changes and modifications to the disclosed embodiment(s), will be apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to fall within the scope of the appended claims.

[0031] As used in this specification and claims, the terms "for example," "e.g.," "for example," "such as," and "like," as well as the verbs "comprise," "have," "include," and other verb forms thereof, when used in conjunction with a list of one or more components or other items, should each be construed as open-ended, meaning that the list should not be considered to exclude other additional components or items. Other terms should be construed using their broadest reasonable meaning unless used in a context requiring a different interpretation. Additionally, the term "and / or" should be construed as an inclusive OR. Thus, for example, the phrase "A, B, and / or C" should be construed as encompassing all of the following: "A," "B," "C," "A and B," "A and C," "B and C," and "A, B, and C."

Claims

1. 1. A seat occupancy sensor system for a vehicle, comprising: at least one seat occupancy sensor configured to receive a radio frequency (RF) signal within a passenger compartment of the vehicle; a seat occupancy control module in communication with the seat occupancy sensor, the seat occupancy control module configured to operate the seat occupancy sensor system in a first mode of operation and a second mode of operation; When at least one vehicle door is open, the seat occupancy control module is configured to operate the seat occupancy sensor system according to the first mode of operation using occupant counting to track vehicle occupants entering and exiting the passenger compartment; and a seat occupancy sensor system, wherein when a vehicle door is not open, the seat occupancy control module is configured to operate the seat occupancy sensor system according to the second mode of operation to detect and distinguish vehicle occupants within the passenger compartment, and the occupant count from the first mode of operation is used as an input to the second mode of operation.

2. 2. The seat occupancy sensor system of claim 1, wherein the seat occupancy control module is configured to receive door status signals indicative of a status of one or more vehicle doors and to select between the first operating mode and the second operating mode based at least in part on the status of the vehicle doors.

3. 2. The seat occupancy sensor system of claim 1, wherein the at least one seat occupancy sensor is a configurable RADAR sensor having one or more settings that can be used to adjust distance resolution, velocity resolution, and / or angular resolution, and the seat occupancy control module is configured to adjust the settings of the seat occupancy sensor based on the operational mode.

4. 4. The seat occupancy sensor system of claim 3, wherein during the first mode of operation in which at least one vehicle door is open, the seat occupancy control module is configured to increase the velocity resolution of the seat occupancy sensor by adjusting one or more chirp parameters and / or implementing one or more signal processing techniques to accurately track the vehicle occupants entering or exiting the passenger compartment.

5. 5. The seat occupancy sensor system of claim 4, wherein during the first mode of operation with at least one vehicle door open, the seat occupancy control module is configured to adjust one or more chirp parameters by increasing chirp duration to improve accuracy of velocity measurements related to the vehicle occupants entering or exiting the passenger compartment.

6. 5. The seat occupancy sensor system of claim 4, wherein during the first mode of operation in which at least one vehicle door is open, the seat occupancy control module is configured to implement one or more of the following signal processing parameters: increasing a Fast Fourier Transform (FFT) size and / or applying a window function to improve accuracy of speed measurements for the vehicle occupants entering or exiting the passenger compartment.

7. 4. The seat occupancy sensor system of claim 3, wherein during the second mode of operation in which a vehicle door is not opened, the seat occupancy control module is configured to increase the distance resolution and / or the angular resolution of the seat occupancy sensor by adjusting one or more chirp parameters and / or implementing one or more signal processing techniques to accurately detect and distinguish vehicle occupants within the passenger compartment.

8. 8. The seat occupancy sensor system of claim 7, wherein during the second mode of operation when a vehicle door is not open, the seat occupancy control module is configured to adjust one or more chirp parameters by increasing a chirp bandwidth and / or a chirp rate to improve accuracy of distance measurements related to seated vehicle occupants within the passenger compartment.

9. 10. The seat occupancy sensor system of claim 7, wherein during the second mode of operation when a vehicle door is not open, the seat occupancy control module is configured to perform one or more of the following signal processing techniques: applying pulse compression techniques to better utilize chirp bandwidth, increasing Fast Fourier Transform (FFT) size, and / or applying a window function to improve accuracy of distance measurements related to seated vehicle occupants in the passenger compartment.

10. 8. The seat occupancy sensor system of claim 7, wherein during the second mode of operation when a vehicle door is not open, the seat occupancy control module is configured to implement the following signal processing technique: digital beamforming to improve the accuracy of angle measurements related to seated vehicle occupants within the passenger compartment.

11. 2. The seat occupancy sensor system of claim 1, wherein the seat occupancy control module is configured to use the occupant count from the first mode of operation to verify the results of the second mode of operation and again detect and distinguish vehicle occupants within the passenger compartment if the occupant count does not match the results of the second mode of operation.

12. 1. A method of using a seat occupancy sensor system for a vehicle, the system comprising at least one seat occupancy sensor configured to receive radio frequency (RF) signals within a passenger compartment of the vehicle, and a seat occupancy control module in communication with the seat occupancy sensor, the method comprising: receiving, at the seat occupancy control module, a door status signal indicative of a status of one or more vehicle doors; selecting, with the seat occupancy control module, a first mode of operation or a second mode of operation based at least in part on the state of the vehicle door; operating the seat occupancy sensor system according to the first mode of operation by tracking vehicle occupants entering and exiting the passenger compartment using occupant counting when at least one vehicle door is open; and operating the seat occupancy sensor system according to the second mode of operation by detecting and distinguishing vehicle occupants within the passenger compartment when a vehicle door is not open, wherein the occupant count from the first mode of operation is used as an input to the second mode of operation.

13. 13. The method of claim 12, wherein during the first mode of operation with at least one vehicle door open, the seat occupancy control module increases the velocity resolution of the seat occupancy sensor by adjusting one or more chirp parameters and / or implementing one or more signal processing techniques to accurately track the vehicle occupants entering and exiting the passenger compartment.

14. 14. The method of claim 13, wherein during the first mode of operation with at least one vehicle door open, the seat occupancy control module adjusts one or more chirp parameters by increasing chirp duration to improve accuracy of velocity measurements for the vehicle occupants entering or exiting the passenger compartment.

15. 14. The method of claim 13, wherein during the first mode of operation in which at least one vehicle door is open, the seat occupancy control module is configured to perform one or more of the following signal processing techniques: increasing a fast Fourier transform (FFT) size and / or applying a window function to improve accuracy of speed measurements for the vehicle occupants entering or exiting the passenger compartment.

16. 13. The method of claim 12, wherein during the second mode of operation in which a vehicle door is not opened, the seat occupancy control module increases the distance resolution and / or the angular resolution of the seat occupancy sensor by adjusting one or more chirp parameters and / or implementing one or more signal processing techniques to accurately detect and distinguish vehicle occupants within the passenger compartment.

17. 17. The method of claim 16, wherein during the second mode of operation when a vehicle door is not open, the seat occupancy control module adjusts one or more chirp parameters by increasing chirp bandwidth and / or chirp rate to improve accuracy of distance measurements for seated vehicle occupants within the passenger compartment.

18. 17. The method of claim 16, wherein during the second mode of operation in which a vehicle door is not open, the seat occupancy control module performs one or more of the following signal processing techniques: applying pulse compression techniques to better utilize chirp bandwidth, increasing Fast Fourier Transform (FFT) size, and / or applying a window function to improve accuracy of distance measurements for seated vehicle occupants in the passenger compartment.

19. 17. The method of claim 16, wherein during the second mode of operation when a vehicle door is not open, the seat occupancy control module implements the following signal processing technique: digital beamforming to improve the accuracy of angle measurements for seated vehicle occupants within the passenger compartment.

20. 13. The method of claim 12, wherein the seat occupancy control module uses the occupant count from the first mode of operation to verify the results of the second mode of operation, and repeats the detecting and distinguishing steps if the occupant count does not match the results of the second mode of operation.

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