Hidden ultrasonic sensing system suitable for advanced driver assistance

Abstract

The invention relates to a hidden ultrasonic sensing system suitable for advanced driver assistance. Exemplary sensor controllers, sensors, sensing systems, and sensing methods that can enable cost-effective implementation of ADAS (Advanced Driver Assistance System) features with hidden sensors. As one example, an exemplary sensing method includes emitting a train of acoustic pulses through a surface on an ultrasonic transducer; receiving the acoustic signal with a MEMS (Micro Electro Mechanical System) microphone, the MEMS microphone representing the acoustic signal as an electrically received signal; and processing the electrical receive signal to detect reflections of the acoustic pulse train.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to provisional U.S. application 63 / 585,120 filed on Sep. 25, 2023 by inventor Marek Hustava, the entire contents of which are hereby incorporated by reference. Background Art

[0003] Modern automobiles are equipped with an astonishing number and variety of sensors that enable a staggering variety of desired features, including "kick-to-open," parking assist, automatic parking, door protection, passenger detection, intrusion monitoring, and blind spot monitoring, to name a few. For example, each of these illustrative features can be implemented by appropriately placed ultrasonic sensors. Design aesthetics often require that such sensors be as inconspicuous as possible, for example, by hiding the sensors behind surfaces that are not blemished by openings, grids, acoustic windows, doors, inserts, or any other visible or tactile indication of a hidden sensor or concealed cavity. (An acoustic window is an area in a surface that is significantly thinned or otherwise differently configured (e.g., with different dimensions or material properties) to better transmit a train of acoustic pulses.) Examples of unblemished surfaces may include the exterior skin of an automobile (e.g., hood, trunk lid, doors, body panels, bumper guards) and interior surfaces (e.g., dashboard, ceiling, interior door panels).

[0004] While concealed ultrasonic sensors have been shown to function well, their functionality can be adversely affected by overlying surfaces. One issue is the attenuation of the acoustic pulse train, which reduces the maximum sensing range. Another issue is the extended reverberation of the piezoelectric element caused by the mechanical coupling between the element and the overlying surface, which can hinder the detection of nearby objects. One proposed solution to these problems employs impedance matching layers to reduce attenuation and employs additional layers or structures of damping material, but the cost of the proposed solution is expected to make it economically unfeasible for automotive applications. Summary of the invention

[0005] Therefore, the present invention discloses an exemplary sensor controller, sensor, sensing system and sensing method that at least partially solve the above problems. As an example, an exemplary sensing method includes: transmitting an acoustic pulse train through a surface on an ultrasonic transducer; receiving the acoustic signal with a MEMS (micro-electromechanical system) microphone, which represents the acoustic signal as an electrical receive signal; and processing the electrical receive signal to detect reflections of the acoustic pulse train.

[0006] An exemplary sensor controller includes: a transmitter configured to drive an ultrasonic transducer to transmit a train of acoustic pulses; a receiver configured to receive an electrical receive signal representing the acoustic signal from a MEMS microphone; and core logic configured to process the electrical receive signal to detect reflections of the train of acoustic pulses.

[0007] An exemplary ADAS (advanced driver assistance system) includes: an ultrasonic transducer configured to emit a train of acoustic pulses through a surface on the ultrasonic transducer; a MEMS (microelectromechanical system) microphone configured to convert a received acoustic signal into an electrical receive signal; and a controller configured to detect reflections of the acoustic pulse train based on the electrical receive signal.

[0008] Each of the above examples may be used alone or in combination, and may include one or more of the following features in any suitable combination: 1. The surface has no openings or acoustic windows for transmitting the acoustic pulse train. 2. The surface includes an aperture for transmitting the acoustic signal to the MEMS microphone. 3. The surface is a bumper cover or body panel of a vehicle. 4. The MEMS microphone is positioned to receive the acoustic signal when the acoustic signal is transmitted to one side or around the edge of the surface. 5. The ultrasonic transducer and the MEMS microphone are part of a concealed assembly, which also includes a controller configured to perform the processing. 6. The ultrasonic transducer is one ultrasonic transducer in an ultrasonic transducer array that cooperatively transmits the acoustic pulse train through the surface. 7. The acoustic pulse train can be diverted by the ultrasonic transducer array. 8. The ultrasonic transducer, the MEMS microphone, and the controller are each part of a concealed assembly that contacts the back side of the surface. 9. The ultrasonic transducer is further configured to convert the acoustic signal into a second electrical receive signal. 10. The controller operates on the second electrical receive signal and the electrical receive signal from the MEMS microphone to detect reflections. 11. The core logic is configured to provide a controllable phase shift between the second electrical receive signal and the electrical receive signal from the MEMS microphone to achieve controllable directional sensitivity. 12. The core logic is configured to determine at least one of a distance, an azimuth, and an elevation angle to a reflector of the acoustic pulse train. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1A is a perspective view of an exemplary vehicle equipped with a concealed ultrasonic sensor.

[0010] Figure 1B is a top view of an exemplary vehicle equipped with a hidden ultrasonic sensor.

[0011] Figure 2 is an isometric view of an exemplary ultrasonic sensor assembly.

[0012] Figure 3 is a block diagram of an exemplary sensor controller.

[0013] Figure 4 is a block diagram of an exemplary ADAS (Advanced Driver Assistance System).

[0014] Figure 5 is a flow chart of an exemplary sensing method using a hidden ultrasonic sensor. DETAILED DESCRIPTION

[0015] It should be understood that the drawings and following description do not limit the disclosure, but rather they provide a basis for one of ordinary skill in the art to understand all modifications, equivalents, and alternatives falling within the scope of the language of the claims.

[0016] As an illustrative use context, Figure 1A A vehicle 102 is shown equipped with a set of ultrasonic transducers 104 that are concealed by an overlying surface 105, which in this case is the cover of the vehicle's bumper. Other placements are also contemplated, where the transducers are attached to (or otherwise abut) the back of a fender, body side panel, hood, trunk lid, door, body panel, or other place beneath the vehicle's skin. Internal placement is also contemplated, for example, for monitoring the vehicle cabin from behind any of the panels and shields that form the lining of the vehicle cabin. In addition to the ultrasonic transducers 104, the vehicle 102 also includes one or more sensors 106, each of which has a MEMS (micro-electromechanical system) microphone that can receive reflections of the acoustic pulse train emitted by the ultrasonic transducer 104. If part of a concealed sensor assembly, the MEMS microphone can be positioned behind a small (e.g., 1 mm-2 mm) hole 107 or acoustic window that allows the acoustic signal to pass to the microphone. Such a hole would be much smaller and less obtrusive than the 2cm-4cm aperture or acoustic window typically used for conventional ultrasonic transducers. Alternatively, the MEMS microphone may be positioned below or behind the edge of a surface (e.g., on the underside of a bumper) to receive acoustic signals passing below or around the edge.

[0017] In certain contemplated embodiments, the ultrasonic transducer 104 is part of a concealed sensor assembly that each includes a MEMS microphone, and similarly, the sensors 106 may each include an ultrasonic transducer concealed behind an overlying surface. In addition to detecting reflections of the acoustic pulse train emitted by the ultrasonic transducer 104, the sensor 106 may also detect reflections of the acoustic pulse train from its integrated ultrasonic transducer, and may also detect acoustic signals in the audible range, such as the sound of a siren from an emergency vehicle. In the case where the ultrasonic transducer 104 is integrated into a concealed sensor assembly with a MEMS microphone, the integrated microphone may also be configured to detect reflections of the acoustic pulse train from the ultrasonic transducer 104, and may be configured to detect acoustic signals in the audible range.

[0018] Figure 1B 1 is a top view of another exemplary vehicle 112 with an ADAS (Advanced Driver Assistance System) sensor arrangement, wherein a concealed ultrasonic transducer 104 and a MEMS microphone sensor 106 are hidden behind an overlying surface 105. Again, the MEMS microphone sensor 106 may also include an ultrasonic transducer. The spaced arrangement of multiple sensors and ultrasonic transducers 104 enables the emitted acoustic pulse train to be controllably steered, and enables directional information to be derived for the detected reflections of the acoustic pulse train, and the determination of distance information may be improved. The illustrated sensor arrangement includes a MEMS microphone sensor 106, wherein an integrated ultrasonic transducer is at each corner of the vehicle 112 and a spaced pair of sensors 106 are at each side of the vehicle. An array of ultrasonic transducers 104 is disposed at the front of the vehicle 112, and a second array of ultrasonic transducers 104 is disposed at the rear of the vehicle. Other arrangements are contemplated, and various tradeoffs may be provided between cost, coverage, detection range, power consumption, and measurement rate.

[0019] The transmitted pulse train propagates outward from the vehicle until it encounters and is reflected by an object or some other form of acoustic impedance mismatch. The reflected pulse train returns to the vehicle as an "echo" of the transmitted pulse train. The time between the transmitted pulse train and the received echo indicates the distance to the reflection point. In many systems, only one sensor transmits at a time, but all sensors can be configured to measure the resulting echo. However, independent simultaneous transmissions can be supported by using orthogonal waveforms, transmissions to non-overlapping detection zones, or transmissions with signatures that can mask any echoes from different transmitters.

[0020] Each of the transducers 104 and sensors 106 is concealed behind the overlying surface 105, except for a small, inconspicuous hole 107 on each MEMS microphone. When positioned behind such holes, on the side of the surface, or behind the edge of the surface, the MEMS microphone exhibits high sensitivity to audible and ultrasonic acoustic signals. The ultrasonic transducer array can be operated cooperatively to increase the effective acoustic pulse train amplitude and enhance the directivity of the transmitted acoustic pulse train. Note that the cooperative operation can be achieved using synchronized operation of the transducers, and the enhanced directivity can be achieved using a controllable phase shift between the transmitted signals. The transducers in each array can preferably be operated simultaneously, but with appropriate processing, such simultaneous operation is not required.

[0021] Figure 2 is an isometric view of an exemplary sensor assembly 106 having an ultrasonic transducer 202 abutting, contacting, attached to, or otherwise mechanically coupled to an overlying surface 105 ( Figure 1A , Figure 1B ) to transmit a train of acoustic pulses through the surface. The sensor assembly 106 includes a substrate 204, such as a PCB (printed circuit board), having control electronics for the sensor assembly. Mounted on the substrate 204 are a sensor controller 206 and a MEMS microphone 208. A hole 210 is provided in the assembly housing to facilitate detection of acoustic signals by the MEMS microphone 210. The hole 210 may be aligned with an unobtrusive hole or acoustic window 107 in the overlying surface, or the assembly 106 may be configured to position the MEMS microphone 208 on one side of the overlying surface or behind the edge of the overlying surface, where it may be sensitive to acoustic signals and unobtrusive. In some contemplated sensor assemblies, the MEMS microphone 208 is vertically displaced from the ultrasonic transducer 202 and may operate in conjunction with the transducer to achieve direction of arrival (DoA) detection, from which the elevation angle of the reflector can be estimated. Alternatively, two vertically spaced MEMS microphones may be used for this purpose. In a similar manner, a MEMS microphone may be displaced horizontally from the ultrasonic transducer to enable estimation of the azimuth angle of a reflector. Two horizontally spaced apart MEMS microphones may alternatively be used for this purpose. Some contemplated sensor assemblies have multiple MEMS microphones that provide horizontal and vertical displacement relative to the transducer or relative to each other, thereby enabling estimation of both elevation and azimuth angles.

[0022] Figure 3 2 shows a block diagram of an exemplary sensor controller 206. It uses IO (input and output) pins that are multiplexed to a selected module among various IO protocol modules. The modules are shown for I 2C (Inter-Integrated Circuit), SPI (Serial Peripheral Interface), and DSI3 (Third Generation Distributed System Interface) communication bus protocols, but these are merely non-limiting examples. Other contemplated protocols include those set forth in the LIN, CAN, and SENT standards. The IO bus 302 couples the various IO protocol modules to the embedded microprocessor (μP). An AMBA (Advanced Microcontroller Bus Architecture) bus (such as, for example, AMB-Lite (Simplified Advanced High-Performance Bus)) can be used to couple the embedded microprocessor to various other functional blocks of the sensor controller 206. Such blocks may include, for example, non-volatile firmware (FW) memory, volatile working memory (MEM), a digital signal processor (DSP), a power-on reset (POR) module, a microphone signal receiver (RX M ) ADC (Analog-to-Digital Converter), for transducer signal receiver (RX T ) of the second ADC, driving the current transmitter (TX I ) and the drive voltage transmitter (TX V ). (The transmitters generate the drive signal for the ultrasonic transducer as a controlled current or a controlled voltage, respectively.) The multiplexer may couple a selected one of the transmitters to the output pin for driving the transducer 202. Figure 3 Further shown is an embedded oscillator (OSC) that generates one or more clock signals for various other blocks, optionally including carrier frequencies for transmitters and receivers. The POR module can control the distribution of clock signals to enable sleep modes for unneeded components and other power saving features.

[0023] The IO pins couple the sensor controller 206 to an ECU (electronic control unit) directly or indirectly (e.g., via a DSI3 bus master). The ECU can transmit commands to the various sensor controllers to, for example, set values ​​for various configuration parameters of the sensor, initiate the transmission of an acoustic burst, and collect signal data or other measurements. The microprocessor in each sensor controller operates according to firmware and stored configuration parameters to interpret commands from the ECU and perform appropriate operations, including the transmission of an acoustic burst and the reception of an acoustic signal.

[0024] In various embodiments, a chirp modulated signal is used, such as a linear frequency modulation ("LFM") chirp. A chirp is a pulse that changes frequency during transmission. An up-chirp is a single pulse whose frequency increases during transmission, and a down-chirp is a single pulse whose frequency decreases during transmission. For clarity, the examples used herein will consider a linear increase or decrease, however, in various embodiments, the increase or decrease is not linear. The chirped echo can be compressed in the correlator without introducing a large amount or any correlated noise. Therefore, peak detection of the echo is facilitated without reducing the time resolution. In addition, the LFM chirp can withstand Doppler shift without the presence of correlated noise increase or with minimal any correlated noise increase. The LFM chirp can be used as a transmit pulse for measuring the distance and direction to an obstacle or object within the sensing range of the sensor system.

[0025] In other specific implementations, an AM (amplitude modulation) signal is used, such as a shaped pulse of a fixed frequency carrier. The AM signaling mode can enable the use of shorter pulse trains (e.g., about 200 microseconds to 300 microseconds), thereby reducing the transmission time and increasing the sensitivity to nearby obstacles. Other specific implementations may use pulses with a modulated carrier (e.g., using binary phase shift keying (BPSK) modulation). For the sake of clarity, the term "burst" as used herein refers to an AM (fixed frequency), BPSK (modulation) or chirped (sweep frequency) pulse, which can be a pulse train in a series of pulse trains generated by driving a piezoelectric element or other ultrasonic transducer. The chirped modulated pulse may have a longer duration than a typical AM pulse, for example greater than 1 millisecond, such as in the range of 2 milliseconds to 3 milliseconds. It is noted here that the pulse train length can be changed, with shorter pulse trains used to facilitate the detection of nearby obstacles and longer pulse trains used to increase the pulse train energy (and echo energy) of obstacles farther away. The pulse train length for detecting nearby obstacles may be half or possibly one quarter of the pulse train length for obstacles further away.The sensor may be switched between modes for different detection distances.

[0026] Although systematically varying the characteristic frequency (e.g., the starting frequency, or equivalently the center or ending frequency) of the chirped modulated pulses in the sequence is considered particularly useful, such frequency variation can also be applied to the carrier frequency of the AM pulses in the sequence. The frequency variation of each pulse can be expressed as a frequency displacement from a nominal characteristic frequency (e.g., a nominal starting frequency or a nominal carrier frequency).

[0027] To transmit a train of acoustic pulses, the microprocessor instructs the selected transmitter to drive an output pin for an ultrasonic transducer, which is coupled to a piezoelectric element PZ. A transformer and / or a resonant tuning network may be provided to amplify the voltage and control the resonant frequency of the transducer. The transmitter may receive a carrier frequency signal having a nominal frequency of, for example, 50 kHz from an oscillator. The transmitter may use the carrier frequency signal to generate a series of AM (amplitude modulation) or chirped pulses, each pulse corresponding to a train of acoustic pulses. An example of a chirped pulse may be a pulse in which the frequency is swept upward from 7 kHz below the carrier frequency to 7 kHz above the carrier frequency (up chirp). Alternatively, a down chirp may be employed in which the frequency is swept linearly downward rather than upward. In some contemplated implementations, the transmitter provides a customized frequency offset pattern to the train of acoustic pulses to serve as a unique signature of the ultrasonic transducer.

[0028] To receive the acoustic signal, the microprocessor instructs one or two ADCs to digitize the electrical receive signal from the MEMS microphone 206 and / or the piezoelectric element 202. The digitized signal can be provided directly to the DSP for real-time processing, or buffered in a memory for subsequent processing by the DSP or ECU. To reduce IO bandwidth requirements, the DSP can implement data compression to reduce the number of bits required to represent the ZIF IQ data or to represent the magnitude of the baseband signal. To further reduce bandwidth requirements, the DSP can perform on-chip processing for peak detection and distance estimation. Various suitable processing techniques for detecting reflections of acoustic pulse trains are known in the art, including co-owned U.S. Patent Publication 2024 / 0069192 "Motion-compensated distance sensing with concurrent up-chirp down-chirp waveforms", which is hereby incorporated by reference into this document.

[0029] Since the received electrical signal is usually in the millivolt or microvolt range, the receiver RX M RX T An amplifier may be included to buffer and amplify the signal from the receive terminal. An analog or digital mixer may be included to down-convert the received signal to baseband for further filtering and processing by the DSP. In one specific implementation, the mixer is an in-phase / quadrature (I / Q) digital mixer that gives zero intermediate frequency (ZIF) IQ data as its output. (Although the term "ZIF" is used herein, the down-converted signal may be a low intermediate frequency or "near baseband" signal in practice.)

[0030] The DSP applies programmable methods to acquire the received signal and detect any echoes and measure their parameters, such as time of flight (ToF), direction of arrival (DoA), duration, and peak amplitude. Such methods may employ threshold comparison, minimum interval, peak detection, zero crossing detection and counting, noise level determination, and other customizable techniques customized to improve reliability and accuracy. It is worth noting that the peak detection process itself has variants, some of which perform rising edge detection, falling edge detection, or peak maximum detection. The nearby obstacle detection process may be performed entirely in the controller 206, or may be shared with or delegated to an ECU or host processor, which receives certain data via a communication bus, as previously described.

[0031] Figure 4 A group of interconnected ECUs (electronic control units) 401-403 organized in a hierarchical bus topology is shown. Of course, other topologies, including serial, parallel, star, and ring topologies, are also suitable and are contemplated for use according to the principles disclosed herein. A first ECU 401 is coupled to an array of ULS transducers 104 and MEMS microphone sensors 106, which may also include ULS transducers. To provide automatic parking or driving assistance, a second ECU 402 may be connected to a group of actuators, such as a turn signal actuator 406, a steering actuator 408, a brake actuator 410, and a throttle actuator 412. A third ECU 403 may be coupled to a user interactive interface 414 to accept user input and provide a display of various measurements and system status. Using these interfaces, sensors, and actuators, the ECUs 401-403 may provide automatic parking, assisted parking, lane change assistance, obstacle and blind spot detection, and other desired features.

[0032] Figure 5 is a flow chart of an exemplary sensing method using a MEMS microphone. Although MEMS microphones are not suitable for generating acoustic pulse trains, their small size, high sensitivity, and decoupling from the acoustic pulse train generator enable detection of reflections of the acoustic pulse train from a hidden ULS transducer despite attenuation and extended transducer reverberation potentially caused by overlying surfaces. The sensing method may be implemented by a sensor controller, by an ECU, or the method steps may be distributed among multiple components of the sensing system. The latter two specific implementations may be preferred when the operation of multiple transducers and sensor assemblies is coordinated.

[0033] If a single sensor assembly implements the method, block 502 may be skipped. Otherwise, the ECU coordinates the operation of the various sensors and transducers that collaborate in obstacle detection / monitoring measurements. Such coordination may include setting measurement parameters (e.g., carrier frequency, burst duration, transmitter and receiver selection), timing synchronization, and trigger signals or measurement initiation commands.

[0034] In block 504, the selected ULS transducers each generate an acoustic pulse train that propagates through and beyond the overlying surface toward the region of interest. The acoustic pulse train reflects from any obstacles within range, and the reflections propagate back to the sensing array, which includes one or more selected MEMS microphones and optionally includes a transmitting ULS transducer or other selected ULS transducers. In block 506, the selected receiver captures the electrical receive signal from the sensing array. Blocks 502-506 can then be repeated with the same or different arrangements of transmitters and receivers to collect additional receive signals.

[0035] When the electrical receive signals are captured, the ECU and / or sensor controller may process them in box 508, applying the techniques described elsewhere to detect the echo and determine the corresponding obstacle distance. Such techniques typically include dynamic gain, filtering, correlation, magnitude determination, threshold comparison, and a combination of multiple measurements to enhance the signal-to-noise ratio and resistance to transient events. In box 510, the ECU and / or sensor controller determines whether an echo has been detected, for example, by determining whether the combined signal exceeds a threshold. If not, the process returns to box 508 to process the next receive signal. If yes, then in box 512, the ECU and / or sensor controller determines at least one of the distance (or equivalently, the travel time between the emission and the echo). The ECU and / or sensor controller may also determine the direction to the reflector, for example, using relative phase information to determine the direction of arrival azimuth and / or elevation. Other suitable direction finding techniques are also provided in the open literature. In block 514 , the ECU and / or sensor controller may report the detected echo information to another ECU or a user to enable the obstacle to be avoided or otherwise taken into account as part of the ADAS system functionality.

[0036] Although for the purpose of explanation Figure 5 The operations shown and described in are considered to occur sequentially, but in practice, the method can be implemented by multiple system components that operate simultaneously and may even operate speculatively to achieve out-of-order operations. This sequential discussion is not intended to be limiting.

[0037] The disclosed system can advantageously provide a cost-effective implementation of covert ultrasonic sensing because it does not require complex damping materials for ULS transducers. MEMS microphones can at least partially avoid potential reverberation problems that would otherwise be faced when using ULS transducers as detectors. In addition, their small size and high sensitivity enable unobtrusive placement and can reduce the number of sensors required for various ADAS system features. MEMS microphones are also inexpensive and consume minimal power. Preliminary tests have shown that the disclosed hidden transducer and sensor arrangement can provide a detection range of more than 5 meters without any visible impact on vehicle aesthetics. Although parking assistance, automatic parking, door protection and kick-open are envisioned vehicle features that can be implemented using the disclosed sensors, other potential uses include sensing passengers and intrusion detection using hidden sensors in the vehicle cabin. Non-vehicle uses may include security monitoring (e.g., in a display case) and traffic monitoring (e.g., at a building entrance).

[0038] Once the above disclosure is fully appreciated, many modifications, equivalents and alternatives will become apparent to those skilled in the art. It is intended that the following claims be interpreted as including all such modifications, equivalents and alternatives where applicable.

Claims

1. A sensing method, comprising: transmitting a train of acoustic pulses through a surface on an ultrasonic transducer; receiving an acoustic signal using a MEMS microphone, wherein the MEMS microphone represents the acoustic signal as an electrical receiving signal; as well as The electrical receive signal is processed to detect reflections of the acoustic pulse train.

2. The sensing method of claim 1, wherein the surface has no openings or acoustic windows for transmitting the acoustic pulse train. 3 . The sensing method of claim 1 , wherein the surface includes an aperture for passing the acoustic signal to the MEMS microphone. The sensing method of claim 3 , wherein the surface is a bumper cover or a body panel of a vehicle. 5 . The sensing method of claim 3 , wherein the MEMS microphone is positioned to receive the acoustic signal when the acoustic signal passes around a side or edge of the surface.

6. The sensing method of claim 1, wherein the ultrasonic transducer and the MEMS microphone are part of a concealed assembly, the concealed assembly further comprising a controller configured to perform the processing.

7. The sensing method of claim 1, wherein the ultrasonic transducer is one of an ultrasonic transducer array that cooperatively transmits the acoustic pulse train through the surface.

8. The sensing method of claim 7, wherein the acoustic pulse train can be steered by the ultrasonic transducer array.

9. The sensing method according to claim 1, further comprising: receiving a second acoustic signal with the ultrasonic transducer, and transmitting the second acoustic signal to a second electrical receiving signal by the ultrasonic transducer, Wherein the processing determines a distance to a reflector based at least in part on the second electrical receive signal and the electrical receive signal from the MEMS microphone.

10. An ADAS advanced driver assistance system, the ADAS comprising: an ultrasonic transducer configured to transmit a train of acoustic pulses through a surface above the ultrasonic transducer; A MEMS micro-electromechanical system microphone, wherein the MEMS microphone is configured to convert a received acoustic signal into an electrical receiving signal; and A controller is configured to detect reflections of the acoustic pulse train based on the electrical receive signal.

11. The ADAS of claim 10, wherein the surface is free of openings or acoustic windows for transmitting the acoustic pulse train. 12 . The ADAS of claim 10 , wherein the surface includes an aperture for passing the acoustic signal to the MEMS microphone.

13. The ADAS of claim 12, wherein the surface is a cover of a vehicle bumper. 14 . The ADAS of claim 12 , wherein the MEMS microphone is positioned to receive the acoustic signal when the acoustic signal passes around a side or edge of the surface. 15 . The ADAS of claim 10 , wherein the ultrasonic transducer, the MEMS microphone, and the controller are each part of a concealed component that contacts a back side of the surface. 16 . The ADAS of claim 10 , wherein the ultrasonic transducer is one of an array of ultrasonic transducers configured to cooperatively transmit the acoustic pulse train through the surface.

17. The ADAS of claim 10, wherein the ultrasonic transducer is further configured to convert the acoustic signal into a second electrical reception signal, and wherein the controller operates the second electrical reception signal and the electrical reception signal from the MEMS microphone to detect the reflection.

18. A sensor controller, comprising: a transmitter configured to drive the ultrasonic transducer to transmit a train of acoustic pulses; a receiver configured to receive an electrical receive signal representing the acoustic signal from the MEMS microphone; and A processor is configured to process the electrical receive signal to detect reflections of the acoustic pulse train.

19. The sensor controller according to claim 18, further comprising: a second receiver configured to receive a second electrical receive signal from the ultrasonic transducer, Wherein the processor is configured to detect the reflection based on each of the second electrical receive signal and the electrical receive signal from the MEMS microphone.

20. The sensor controller of claim 19, wherein the processor is configured to provide a controllable phase shift between the second electrical receive signal and the electrical receive signal from the MEMS microphone to achieve controllable directional sensitivity.

Images