Vehicle seat occupancy sensor system and method of use

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 generally relates to sensor systems for vehicles, and more particularly to seat occupancy sensor systems that use radio frequency (RF) sensors.

Background Art

[0002] Various types of sensors have been used in vehicles to determine the occupancy status of front seats 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 specific drawbacks. Pressure sensors and capacitance sensors can detect and distinguish seat occupancy, but systems that use such sensors can be expensive because separate sensors are required for each seat. On the other hand, a single ultrasonic sensor can detect movement of multiple seats and their surroundings, but may not have the resolution to accurately distinguish occupants, particularly when the occupants are sitting very close to each other or when sitting in the second or third row of the vehicle.

Summary of the Invention

[0003] According to one embodiment, an exemplary embodiment of a seat occupancy sensor system for a vehicle is provided, comprising: at least one seat occupancy sensor configured to receive radio frequency (RF) signals within the passenger compartment of a vehicle; and a seat occupancy control module communicating with the seat occupancy sensor, 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 counts; and when the vehicle door is closed, 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, wherein occupant counts from the first operating mode are used as inputs to the second operating mode.

[0004] In another aspect, an exemplary embodiment of a method for 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 in the passenger compartment of a vehicle, and a seat occupancy control module communicating with the seat occupancy sensor, the method comprising: the seat occupancy control module receiving a door status signal indicating the status of one or more vehicle doors; using the seat occupancy control module to select a first or second operating mode based at least partially on the status of the vehicle doors; operating the seat occupancy sensor system according to the first operating mode by tracking vehicle occupants entering and exiting the passenger compartment using an occupant count when at least one vehicle door is open; and operating the seat occupancy sensor system according to the second operating mode by detecting and distinguishing vehicle occupants in the passenger compartment when the vehicle doors are closed, wherein the occupant count from the first operating mode is used as an input to the second operating mode.

[0005] Any number of individual features of the embodiments described above and any other embodiments shown in the following drawings or description are intended to be combined in any combination to define the invention, unless the features are incompatible. [Brief explanation of the drawing]

[0006] Exemplary embodiments will be described with reference to the following drawings, where similar numbers in the drawings indicate similar elements. [Figure 1] This is a schematic diagram showing an example of a seat occupancy sensor system installed in the passenger compartment of a vehicle. [Figure 2] Figure 1 is a schematic block diagram of the seat occupancy sensor system. [Figure 3] A flowchart illustrating an example of how to use a seat occupancy sensor system, such as the seat occupancy sensor system shown in Figure 1. [Modes for carrying out the invention]

[0007] This paper describes a seat occupancy sensor system and method for detecting and distinguishing vehicle occupants in the passenger compartment of a vehicle using radio frequency (RF) sensors. The system and method can be used with any type of vehicle, including, to name a few, automobiles, trucks, sports utility vehicles (SUVs), off-road vehicles (ORVs), crossover vehicles, and commercial vehicles, powered by conventional internal combustion engines, electric motors, or hybrid powertrains having both. The output of the system and method can be provided to and used by any number of different vehicle systems and / or modules, such as seat belt warning systems, airbag deployment systems, collision avoidance systems, safety systems, and infotainment systems.

[0008] Referring here to Figure 1, a schematic diagram of a seat occupancy sensor system 10 installed in the passenger compartment 12 of a vehicle 14 is shown. For 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 that communicates with the sensors. The seat occupancy sensor system and method can operate strategically 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 can operate according to a first operating mode that tracks vehicle occupants entering and exiting the passenger compartment using RF signals. When the doors are closed (and possibly when the vehicle is in motion), the seat occupancy sensor system and method may operate according to a second operating mode in which RF signals are used to detect and distinguish vehicle occupants in the passenger compartment, and the number of occupants from the first mode is used as input to the second mode. These different operating modes may help improve the accuracy and / or performance of the seat occupancy sensor system 10, in particular 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 against or stretching out in adjacent seats (all of which can make accurate occupant sensing difficult).

[0009] The seat occupancy sensors 20 and 22 are mounted in strategic locations within the passenger compartment 12 and use radio frequency (RF) signals to detect objects and / or movement within the passenger compartment. For example, the seat occupancy sensor 20 may be mounted on or near the A-pillar 40 or the roof panel 50 and directed toward the driver's seat 42 and / or the passenger seat 44 to detect objects and / or movement in the space associated with these seats. If the sensor 20 detects movement of an object, the seat occupancy sensor system 10 can conclude that a vehicle occupant is seated in one or both of the front seats. The seat occupancy sensor 22, on the other hand, may be mounted on or near the B-pillar 46, the C-pillar 48, or the roof panel 50 and may be directed toward the second row to sense occupants seated in the rear driver's seat 52, the rear passenger seat 54, and / or the rear center seat 56. Thus, multiple occupants can be detected and distinguished using a single seat occupancy sensor 20 or 22. It should be noted that the system and method are not limited to the exemplary embodiments schematically shown in Figure 1, and 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, and 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., a total of four sensors). Instead of having only two rows, the vehicle may have three rows with one or two sensors per row (e.g., a total of three or six sensors). 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. Instead of all 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 on the back of the headrests 60, 62 or near the rear window. The above examples represent only some of the possible sensor arrangements that may be utilized by the system and method, and others may be used in the same way.

[0010] The seat occupancy sensors 20 and 22 can be active sensors that actively emit electromagnetic signals in the RF frequency range (approximately 20 kHz to 300 GHz), receive reflected signals bounced back from various objects, and analyze the reflected signals according to radio wave detection ranging (RADAR) technology to determine the presence of occupants in various seats. The active RADAR sensors, seat occupancy sensors 20 and 22, may include a transmitter, receiver, and antenna, all of which are integrated into the same unit or device and are sometimes referred to as a monostatic RADAR device. The seat occupancy sensors 20 and 22 can be configured so that the system and method (e.g., seat occupancy control module 30) can control or adjust specific settings such as distance resolution, velocity resolution, and / or angular resolution, as will be described in more detail later.

[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 to reflected RF signals emitted by different sources. For example, the seat occupancy sensors 20, 22 may listen to reflected WiFi signals (2-5 GHz), Bluetooth signals (2.4 GHz), and / or other RF signals already present in the passenger compartment 12. If the vehicle 14 has an infotainment system 66 that is already transmitting RF signals throughout the passenger compartment 12 (for example, at a frequency of about 5 GHz), the seat occupancy sensors 20, 22 may be positioned and configured to passively listen to 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 called 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 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. Electronic modules, also called electronic control units, electronic controllers, or simply controllers, have embedded software to perform their defined tasks or functions and are connected to numerous other electronic devices throughout the vehicle via a certain type of wired or wireless internal communication network (e.g., a vehicle bus). The vehicle 14 may include any suitable combination or arrangement of electronic modules and / or communication networks, and may include, but is not limited to, the specific embodiments schematically shown in Figure 1 or described herein, the body control module 70, the seat belt warning system 72, and any suitable combination of other components, devices, units, modules, controllers, and / or systems known in the art. The modules and systems described herein may be standalone units or may be integrated with or combined with other modules and systems. According to one non-limiting example, the seat occupancy control module 30, as shown in Figure 2 and further described below, includes an application manager unit 100, a vehicle interface unit 110, a signal processing unit 120, and a decision unit 130. Note that one or more seat occupancy control modules 30 may be integrated with or combined with one or more seat occupancy sensors 20, 22 (for example, each sensor having its own integrated control module), or they may be separate units.

[0013] A body control module (BCM) 70 is configured to monitor and control specific functions related to the vehicle body, such as doors, door locks, windows, and lights. According to one embodiment, the BCM 70 is connected to a seat occupancy control module 30 via an internal communication network, such as that of 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 a door status signal indicating the state or status of one or more of the vehicle doors, thereby indicating whether such doors are open or closed. Since door sensors can monitor the status of different vehicle doors and can be connected (directly or indirectly) to an internal communication network to provide door status signals and the like to the system and method, the BCM 70 does not need to transmit door status signals.

[0014] The seat belt warning system 72 is configured to monitor and control certain safety features, such as seat belts and those related to their status. For example, the seat belt warning system 72 generates alerts or warnings to the driver or other vehicle occupants, as well as to other modules and / or systems in 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 the occupants to fasten their seat belts, or it may send a seat belt status signal indicating the occupants' seat belt status to other systems in the vehicle, such as an airbag deployment system.

[0015] Referring to Figures 2 and 3, schematic block diagrams of Method 200 for using the seat occupancy control module 30 and the seat occupancy sensor system 10 are shown. Method 200 can be initiated at different times, including when triggered by one of several trigger events, such as when a vehicle door is opened (step 210). For example, when a vehicle door is opened, a 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 may include a vehicle interface unit 110 having a door event detection application 150 that receives and processes the door status signal, the door event detection application may later send the corresponding signal to an application manager unit 100. The vehicle interface unit 110 may 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 the opening of a vehicle door, the method can initiate a first operating mode that tracks and counts the number of occupants entering and exiting the passenger compartment (step 220). Tracking occupants within the vehicle can improve the accuracy of the system and method as it provides useful data points. 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 distance resolution, velocity resolution, and / or angular resolution. Those skilled in the art will understand that optimizing certain settings of the RADAR or RF sensors can improve some performance characteristics while negatively impacting others. Since the first operating mode 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 operating mode to optimize the velocity resolution of the seat occupancy sensors 20, 22. Increasing the velocity resolution of the sensors allows the first operating mode 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 cannot be achieved without trade-offs, as the distance resolution and / or angular resolution of the seat occupancy sensors 20, 22 may be affected to some extent. The seat occupancy control module 30 may also 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 changes specific parameters based on the selected operating mode, as described later.

[0017] Possible methods for step 220 to increase the speed resolution during the first operating mode include adjusting the configuration of the chirp parameters and / or implementing signal processing techniques used in conjunction with the seat occupancy sensors 20, 22. As used herein, the terms “chirp” or “chirp signal” broadly include 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 frequency and the chirp end frequency); the chirp duration is the duration of the chirp signal (typically the time delta between the chirp start frequency and the chirp end frequency); and the chirp rate is the rate at which the chirp frequency changes (typically the chirp bandwidth / chirp duration). Increasing the chirp duration in the first operating mode (for example, increasing it to about 10-100 μs) can enable finer resolution of the Doppler frequency, which in turn increases the accuracy or precision of velocity measurements with respect to moving targets. Furthermore, providing stable chirp generation helps ensure that the chirp signal remains stable over the chirp duration, because instability in the chirp signal can reduce the accuracy of Doppler measurements and, therefore, the accuracy of velocity measurements with respect to moving targets, such as occupants entering and exiting a vehicle.

[0018] While the aforementioned example demonstrates 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 signal or echo to better identify the Doppler frequency shift corresponding to the velocity measurement of a moving target. Another signal processing technique that can be optimized by the first operating mode in step 220 concerns the FFT size. Increasing the FFT size allows for finer frequency resolution in the Doppler region, which in turn results in better velocity resolution. Yet another possible signal processing technique that can be optimized in step 220 concerns the application of a window function (e.g., Hamming window, Hanning window, or Blackman window) in the Doppler processing to reduce spectral leakage. The aforementioned example is a signal processing technique that can be employed by the system and method to enhance or improve the velocity resolution of the system during the first operating mode, in which occupants are most likely to enter and exit the vehicle. Other signal processing techniques may be used similarly. The selection of the operating mode and / or optimization of the velocity resolution performed in step 220 may be carried out by command signals 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 application 160 or an ML data quality improvement application 164. The selection of the operating mode and / or optimization of the velocity resolution may also be performed within and / or by sensors 20, 22.

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

[0020] As long as one or more vehicle doors remain open, the method can track occupants entering and exiting the vehicle (step 240). Door status signals provided by the body control module (BCM) 70 or any other sensors, devices, and / or modules 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 vehicle doors are closed, in addition to that the vehicle is "in motion" or moving, before proceeding to the next step. The seat occupancy control module 30 may use the door event detection application 150 and / or vehicle state detection application 154 in the vehicle interface unit 110 to make the determination in step 240 and send the corresponding signal to the application manager unit 100.

[0021] Next, step 250 starts a second operating mode in which vehicle occupants in the passenger compartment are detected and distinguished, and the occupant count from the first operating mode is used as input. Step 220 may need to modify or adjust certain settings of the seat occupancy sensors 20, 22, such as distance resolution, velocity resolution and / or angular resolution, in order to produce accurate results. Previously, this method optimized the velocity resolution of the system in the first operating mode to better detect occupants entering and 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 occupants may be seated very close to each other, but only nearly stationary or moving minimally in each seat. Under these conditions, velocity resolution is not as critical to the performance of the seat occupancy sensor system 10 as distance resolution and / or angular resolution. Therefore, step 250 may increase the distance resolution and / or angular resolution during the second operating mode by adjusting the chirp parameters and / or signal processing techniques associated with the seat occupancy sensors 20, 22.

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

[0023] While the aforementioned examples illustrate different ways in which the second operating mode can increase distance and / or angular resolution by manipulating different chirp parameters, the second operating mode can also improve distance and / or angular resolution by implementing different signal processing techniques. For example, step 250 can improve the distance resolution of seat occupancy sensors 20, 22 by implementing pulse compression techniques to better utilize the increased chirp bandwidth, because pulse compression typically improves the signal-to-noise ratio (SNR) of the received RF signal. This, in turn, allows for better distinction of targets with respect to distance, which can be useful when trying to distinguish different occupants seated very close to each other. Step 250 may also apply a window function (e.g., Hamming window, Hanning window, or Blackman window) to the received RF signal before performing the FFT, thereby reducing side lobes and improving resolution. Another example of a signal processing technique that can be utilized in step 250 to optimize distance resolution concerns manipulating the size of the FFT. Using a larger FFT size during distance processing can provide finer resolution in the frequency domain, which in turn results in greater distance resolution.

[0024] There are also signal processing techniques that can be implemented or applied in step 250 to optimize the angular resolution, which can provide a more accurate spatial representation of the passenger compartment and enable improved passenger position determination and / or identification. One such signal processing technique is digital beamforming, which may be well suited to detect and / or distinguish slow-moving or stationary targets (e.g., passengers seated in a seat) that are sitting close together or may be obscured by an arm or leg in an adjacent seat. Digital beamforming involves the use of multiple transmit antennas and multiple receive antennas (e.g., seat occupancy sensors 20, 22, and others) that are focused in a particular direction (e.g., azimuth and / or elevation directions), especially in the context of a MIMO FMCW millimeter-wave RADAR system. Implementing beamforming techniques in step 250 can help enable the system and method to accurately control the beam direction and enhance the angular resolution. In one example, step 250 uses digital beamforming techniques to focus or direct seat occupancy sensors 20, 22 towards an area or space within the passenger compartment corresponding to a particular seat (the system has knowledge of the interior layout or geometry of the passenger compartment). A single seat occupancy sensor 20, 22 can potentially monitor multiple seats, and the sensor can be directed towards the boundary between adjacent seats being monitored, the center of a particular seat being monitored, or different targets. Other beamforming and / or signal processing techniques can similarly be reliably applied and implemented.

[0025] The foregoing example is a signal processing technique that can be employed by the present system and method to enhance or improve the distance resolution and / or angular resolution of the system during a second operating mode in which an occupant is most likely seated in a different seat in the passenger compartment. Other signal processing techniques can be used as well. The selection of the operating mode performed at step 250, and / or the optimization of the distance resolution and / or angular resolution, can be implemented by a command signal transmitted 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.

[0026] Next, step 260 detects and differentiates an occupant within the passenger compartment according to a second operating mode, sometimes referred to as a "position identification mode." According to one example, 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 position identification mode is designed to optimize the distance resolution and / or angular resolution of the system when all vehicle doors are closed and an occupant is likely seated in their seat (e.g., when the vehicle is being driven). This optimization, which may sacrifice speed resolution, improves the accuracy of the position identification mode at step 260, but it may still be difficult to distinguish an occupant seated near another occupant, especially when the occupants are not moving much.

[0027] Therefore, step 260 considers and / or otherwise considers the occupant count from the first operating mode as input to the second operating mode. In one example, step 260 first determines the number and location of occupants in the passenger compartment according to the second operating mode, and then compares this information with the occupant count from the first operating mode. If the occupant count verifies or confirms the discovery result from the location-finding mode, whether vehicle-based, row-based, and / or seat-based, step 270 can conclude that the method has accurately detected and identified one or more vehicle occupants in the passenger compartment and sends control to step 280. On the other hand, if the occupant count does not confirm the discovery result from the location-finding mode (for example, if different occupant counts are indicated for vehicle-based, row-based, and / or seat-based), step 270 can return control to step 260 and repeat the step using the same parameters and techniques of the second operating mode previously used. In a different example where the occupant count does not match the detection result of the localization mode, step 270 may send control of the method back 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 the first and second operating modes together in coordination can have the desirable effect of reducing false detections or misjudgments (i.e., sensing an occupant when one is not actually present) and detection misses or failures (i.e., not sensing an occupant when one is actually present). The above examples are just some of the possibilities of how the occupant count from the first operating mode may be used as input to the second operating mode, as other examples are certainly possible. Occupant detection and distinction, as well as confirmation of the outputs of the two different operating modes performed in step 260, may be performed by a signal processing unit 120 (e.g., localization signal processing application 162) and / or a decision unit 130 (e.g., ML localization decision application 170 and / or RB localization decision application 172).One or more units within the seat occupancy control module 30 may also use machine learning and / or artificial intelligence (AI) driven algorithms, rule-based algorithms, and / or a combination of both to perform these steps. The output from these applications may be returned, for example, to the application manager unit 100 and / or the vehicle interface unit 110.

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

[0029] In different embodiments, method 200 may be modified so that occupant counting and tracking by a first operating mode (steps 220, 230) and / or occupant detection and differentiation by a second operating mode (steps 250, 260) are performed whenever the seat belt status changes for one or more occupants. This may also apply if the vehicle doors remain closed and / or open, as the change in seat belt status can act 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 embodiments(s) disclosed herein, but rather is defined solely by the following claims. Furthermore, the descriptions contained herein relate to specific embodiments and should not be construed as limitations on the definitions of terms used in the scope of the invention or in the claims, unless terms or phrases are expressly defined above. Various other embodiments, as well as various changes and modifications to the disclosed embodiments(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] Where used herein and in the claims, the terms “for example,” “for instance,” “as an example,” “etc.,” and “similarly,” as well as the verbs “equip,” “have,” “include,” and their other verb forms, when used in conjunction with an enumeration of one or more components or other items, should each be interpreted as open-ended, meaning that the enumeration should not be considered to exclude any other additional components or items. Other terms should be interpreted using their broadest and most reasonable meaning unless used in a context requiring a different interpretation. In addition, the term “and / or” should be interpreted as an inclusive OR. Thus, for example, the phrase “A, B, and / or C” should be interpreted 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. A seat occupancy sensor system for vehicles, The vehicle includes at least one seat occupancy sensor configured to receive radio frequency (RF) signals within the passenger compartment, A seat occupancy control module that communicates with the seat occupancy sensor, the seat occupancy control module is configured to operate the seat occupancy sensor system in a first operating mode and a second operating mode, 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 operating mode which tracks vehicle occupants entering and exiting the passenger compartment using occupant counting, When the vehicle door is closed, the seat occupancy control module is configured to operate the seat occupancy sensor system according to a second operating mode for detecting and distinguishing vehicle occupants in the passenger compartment, wherein the occupant count from the first operating mode is used as an input to the second operating mode.

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

3. The seat occupancy sensor system according to 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 operating mode.

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

5. The seat occupancy sensor system according to claim 4, wherein during the first operating mode in which at least one vehicle door is open, the seat occupancy control module is configured to adjust one or more chirp parameters by increasing the chirp duration in order to improve the accuracy of speed measurement with respect to the vehicle occupants entering and exiting the passenger compartment.

6. The seat occupancy sensor system according to claim 4, wherein during the first operating mode 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 the fast Fourier transform (FFT) size and / or applying a window function to improve the accuracy of speed measurements relating to the vehicle occupants entering and exiting the passenger compartment.

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

8. The seat occupancy sensor system according to claim 7, wherein during the second operating mode in which the vehicle door is not open, the seat occupancy control module is configured to adjust one or more chirp parameters by increasing the chirp bandwidth and / or chirp rate in order to improve the accuracy of distance measurement with respect to a seated vehicle occupant in the passenger compartment.

9. During the second operating mode in which the 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 the chirp bandwidth; increasing the fast Fourier transform (FFT) size; and / or applying a window function to improve the accuracy of distance measurements with respect to seated vehicle occupants in the passenger compartment, according to claim 7.

10. During the second operating mode in which the vehicle door is not open, the seat occupancy control module is configured to perform the following signal processing technique, namely digital beamforming, to improve the accuracy of angle measurements with respect to a seated vehicle occupant in the passenger compartment, according to claim 7.

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

12. A method for 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 in the passenger compartment of the vehicle, and a seat occupancy control module communicating with the seat occupancy sensor, the method being: The seat occupancy control module includes the step of receiving a door status signal indicating the status of one or more vehicle doors, The steps include selecting a first operating mode or a second operating mode using the seat occupancy control module, based at least partially on the state of the vehicle door, The steps include operating the seat occupancy sensor system according to the first operating mode by tracking vehicle occupants entering and exiting the passenger compartment using occupant counting when at least one vehicle door is open, A method comprising the step of operating the seat occupancy sensor system according to a second operating mode by detecting and distinguishing vehicle occupants in the passenger compartment when the vehicle door is closed, wherein the occupant count from the first operating mode is used as an input to the second operating mode.

13. The method according to claim 12, wherein during the first operating mode in which at least one vehicle door is open, the seat occupancy control module increases the speed 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. The method according to claim 13, wherein during the first operating mode in which at least one vehicle door is open, the seat occupancy control module adjusts one or more chirp parameters by increasing the chirp duration in order to improve the accuracy of speed measurement with respect to the vehicle occupants entering and exiting the passenger compartment.

15. The method according to claim 13, wherein during the first operating mode 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 the fast Fourier transform (FFT) size and / or applying a window function to improve the accuracy of speed measurements relating to the vehicle occupants entering and exiting the passenger compartment.

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

17. The method according to claim 16, wherein during the second operating mode in which the vehicle door is not open, the seat occupancy control module adjusts one or more chirp parameters by increasing the chirp bandwidth and / or chirp rate in order to improve the accuracy of distance measurement with respect to a seated vehicle occupant in the passenger compartment.

18. The method according to claim 16, wherein during the second operating mode in which the 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 the chirp bandwidth, increasing the fast Fourier transform (FFT) size, and / or applying a window function to improve the accuracy of distance measurements with respect to seated vehicle occupants in the passenger compartment.

19. The method according to claim 16, wherein during the second operating mode in which the vehicle door is not open, the seat occupancy control module implements the following signal processing technique, namely digital beamforming, to improve the accuracy of angle measurements with respect to a seated vehicle occupant in the passenger compartment.

20. The method according to claim 12, wherein the seat occupancy control module verifies the result of the second operating mode using the occupant count from the first operating mode, and repeats the detection and distinction step if the occupant count does not match the result of the second operating mode.

Images