Ultrasonic ranging chip, ultrasonic ranging device and adaptive threshold generation method

Abstract

Embodiments of the present disclosure provide an ultrasonic ranging chip, an ultrasonic ranging device and a self-adaptive threshold generation method. The ultrasonic ranging chip comprises an echo signal processing module, a near-field threshold generator and a near-field decision maker. The echo signal processing module is configured to receive a target echo signal generated by an ultrasonic transducer and generate a near-field echo envelope signal based on the target echo signal. The near-field threshold generator comprises a filter configured to obtain a model configuration parameter for the filter, and use the filter to predictively generate a self-adaptive threshold based on the near-field echo envelope signal, wherein the gain of the filter is adaptively adjusted based on the model configuration parameter and the near-field echo envelope signal. The near-field decision maker is configured to generate first alarm information according to the near-field echo envelope signal and the self-adaptive threshold. The embodiments of the present disclosure realize adaptive threshold generation in near-field target detection, reduce the false alarm rate and the missed alarm rate of the decision maker, and realize accurate detection of near-field targets.

Description

Technical Field

[0001] Embodiments of this disclosure relate to an ultrasonic ranging chip, an ultrasonic ranging device, and an adaptive threshold generation method. Background Technology

[0002] In automotive applications such as traditional gasoline-powered vehicles or new energy vehicles, automated guided vehicles (AGVs) (e.g., robotic vacuum cleaners or logistics robots), and unmanned aerial vehicles (UAVs) (e.g., consumer drones or drone arrays), ultrasonic ranging sensors (or "ultrasonic radar") are frequently used. An ultrasonic ranging sensor is a short-range ranging sensor based on the Time of Flight (ToF) principle, using ultrasonic waves as the measurement medium. In the automotive field, it is mainly used for parking assistance, blind spot monitoring, automatic parking, and low-speed emergency braking. Near-field echo threshold generation and decision-making are challenges in the design and implementation of ultrasonic ranging chips in the automotive industry. Summary of the Invention

[0003] At least one embodiment of this disclosure provides an ultrasonic ranging chip, including an echo signal processing module, a near-field threshold generator, and a near-field decision unit. The echo signal processing module is configured to receive a target echo signal generated by an ultrasonic transducer and generate a near-field echo envelope signal based on the target echo signal. The near-field threshold generator includes a filter and is configured to acquire model configuration parameters for the filter, and use the filter to predict and generate an adaptive threshold based on the near-field echo envelope signal. The gain of the filter is adaptively adjusted based on the model configuration parameters and the near-field echo envelope signal. The near-field decision unit is configured to generate a first alarm message based on the near-field echo envelope signal and the adaptive threshold.

[0004] For example, at least one embodiment of the ultrasonic ranging chip provided in this disclosure further includes a drive controller and a drive circuit, wherein the drive controller is configured to send a pulse signal to the drive circuit; and the drive circuit is configured to generate a drive signal based on the pulse signal to drive the ultrasonic transducer.

[0005] For example, at least one embodiment of the present disclosure provides an ultrasonic ranging chip, wherein the echo signal processing module includes an echo digital code value generator and an echo envelope signal generator, wherein the echo digital code value generator is configured to receive a target echo signal and perform analog-to-digital conversion on the target echo signal to obtain an echo digital code value, and the echo envelope signal generator is configured to receive the echo digital code value and generate a near-field echo envelope signal based on the echo digital code value.

[0006] For example, at least one embodiment of the present disclosure provides an ultrasonic ranging chip, wherein the echo digital code value generator includes an amplifier and an analog-to-digital converter, wherein the amplifier is configured to amplify the target echo signal to obtain an amplified target echo signal; and the analog-to-digital converter is configured to sample the amplified target echo signal and obtain an echo digital code value through analog-to-digital conversion.

[0007] For example, at least one embodiment of the ultrasonic ranging chip provided in this disclosure includes an echo envelope signal generator comprising a mixer, a low-pass filter, and an amplitude synthesizer. The mixer is configured to perform frequency conversion on the echo digital code value to obtain an echo digital code value of a first frequency; the low-pass filter is configured to filter out high-frequency signals in the echo digital code value of the first frequency to obtain an echo digital code value of a second frequency; and the amplitude synthesizer is configured to perform amplitude synthesis on the echo digital code value of the second frequency to obtain a near-field echo envelope signal.

[0008] For example, at least one embodiment of the ultrasonic ranging chip provided in this disclosure further includes a residual vibration time measurement module, which is configured to acquire the residual vibration time of the ultrasonic transducer. The model configuration parameters include residual vibration time, sampling time interval of analog-to-digital converter, observation matrix, system model confidence level, and observation confidence level.

[0009] For example, at least one embodiment of the ultrasonic ranging chip provided in this disclosure uses a Kalman filter, wherein the state transition equation of the Kalman filter is a linear equation, and is obtained by the following formula:

[0010]

[0011] Where F is the state transition equation, Ts is the sampling time interval of the analog-to-digital converter, and τ reg For the remaining time.

[0012] For example, in at least one embodiment of the present disclosure, an ultrasonic ranging chip is provided in which, when the intensity of the ultrasonic signal emitted by the ultrasonic transducer decreases inversely with the square of the transmission distance, the state transition equation of the filter is a nonlinear equation. The filter is an extended Kalman filter or an unscented Kalman filter, configured to linearize the state transition equation, or the filter is a particle filter, configured to linearize the state transition equation.

[0013] For example, at least one embodiment of the ultrasonic ranging chip provided in this disclosure further includes a far-field threshold generator and a far-field decision unit, wherein the echo signal processing module is further configured to receive and generate a far-field echo envelope signal based on the target echo signal, wherein the far-field threshold generator is configured to generate a first threshold based on the far-field echo envelope signal; and the far-field decision unit is configured to generate a second alarm message based on the far-field echo envelope signal and the first threshold.

[0014] At least one embodiment of this disclosure also provides an ultrasonic ranging device, including an ultrasonic transducer and an ultrasonic ranging chip in any embodiment, wherein the ultrasonic transducer is configured to receive a drive signal from the ultrasonic ranging chip to emit ultrasonic waves, and to receive reflected ultrasonic waves to obtain a target echo signal.

[0015] At least one embodiment of this disclosure also provides an adaptive threshold generation method for near-field echo detection in an ultrasonic ranging chip, comprising: generating a near-field echo envelope signal based on a target echo signal generated by an ultrasonic transducer; obtaining model configuration parameters for a filter; using the filter to predict and generate an adaptive threshold based on the near-field echo envelope signal, wherein the gain of the filter is adaptively adjusted based on the model configuration parameters and the near-field echo envelope signal; and generating alarm information based on the near-field echo envelope signal and the adaptive threshold.

[0016] For example, the adaptive threshold generation method provided in at least one embodiment of this disclosure further includes: obtaining the residual vibration time of the ultrasonic transducer, wherein the model configuration parameters include the residual vibration time, the sampling time interval of the analog-to-digital converter, the observation matrix, the system model confidence level, and the observation confidence level.

[0017] For example, at least one embodiment of this disclosure provides an adaptive threshold generation method, wherein the filter is a Kalman filter, the state transition equation of the Kalman filter is a linear equation, and is obtained by the following formula:

[0018]

[0019] Where F is the state transition equation, Ts is the sampling time interval of the analog-to-digital converter, and τ reg For the remaining time. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this disclosure and are not intended to limit this disclosure.

[0021] Figure 1 The waveform diagram corresponds to the overall measurement process of the ultrasonic ranging chip;

[0022] Figure 2 The waveform diagram shows the near-field echo envelope signal in the ultrasonic ranging chip.

[0023] Figure 3 This is a waveform diagram of near-field echo envelope signal processing based on an α filter;

[0024] Figure 4 Waveform diagram of another near-field echo signal processed based on α filter;

[0025] Figure 5 This is a schematic block diagram of an ultrasonic ranging chip provided in at least one embodiment of the present disclosure;

[0026] Figure 6 A flowchart for generating near-field echo thresholds based on a Kalman filter is provided for at least one embodiment of this disclosure;

[0027] Figure 7 This is a near-field echo threshold waveform diagram generated based on a Kalman filter, provided in at least one embodiment of this disclosure;

[0028] Figure 8 A flowchart for generating near-field echo thresholds based on an extended Kalman filter, provided for at least one embodiment of this disclosure;

[0029] Figure 9 This is a schematic block diagram of an ultrasonic ranging device provided in at least one embodiment of the present disclosure;

[0030] Figure 10 An example of an ultrasonic ranging device provided for at least one embodiment of this disclosure; and

[0031] Figure 11 A flowchart of an adaptive threshold generation method provided for at least one embodiment of this disclosure. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0033] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0034] Near field refers to the location of the target being measured very close to the ultrasonic probe, generally within a space of about 5cm to 50cm. For ultrasonic transducers that generate ultrasound based on the mechanical resonance of piezoelectric materials, after the wave emission stops (i.e., after the driving electrical signal stops), due to the characteristics of piezoelectric materials, they do not immediately return to their original shape and stop vibrating. In fact, there is a period of after-vibration, meaning that the damping of the transducer continues to vibrate for an additional period of time with a gradually decreasing amplitude. Subsequently, the ultrasonic signal additionally excited by the after-vibration process will stabilize. It should be noted that the intensity of the additional sound wave excited by the ultrasonic transducer due to after-vibration is usually much smaller than the intensity of the initial excited pulse.

[0035] Figure 1 This is a waveform diagram corresponding to the overall measurement process of the ultrasonic ranging chip. For example... Figure 1 As shown, the overall measurement process includes the ultrasonic transducer's beam excitation process, continuous vibration process, after-vibration process, and distance measurement process. Specifically, under the action of a voltage signal, the ultrasonic transducer generates mechanical resonance, thereby exciting a high-intensity initial beam pulse. Then, the ultrasonic transducer continuously vibrates to maintain the excited beam intensity, and the generated ultrasonic beam is emitted into the environment to measure the distance between surrounding objects and the ultrasonic ranging chip. When the voltage signal stops, the ultrasonic transducer continues to vibrate for a certain period of time until the after-vibration ends.

[0036] Figure 2 This is a waveform diagram of the near-field echo envelope signal in an ultrasonic ranging chip. For example... Figure 2As shown, due to the influence of the aftershock process of the ultrasonic transducer, if the target object is very close, the time it takes for the ultrasonic wave emitted from the transducer to reach the target and reflect back may be very short. This means that the ultrasonic transducer may receive the target echo signal while still undergoing the aftershock phase (i.e., the ultrasonic transducer is used to both emit ultrasonic waves and detect the target echo signal). Consequently, the target echo signal in the near field (e.g., the distance at which the target echo signal is received during the aftershock phase) will be superimposed on the aftershock signal. That is, the ultrasonic wave returning during the aftershock process has already arrived, causing the ultrasonic transducer to start vibrating again, forming... Figure 2 The three valid signal peaks shown are 1-3. Peak 1 is formed when the emitted wave is first reflected back to the vehicle by the obstacle. Peak 2 is formed when the echo (peak 1) is reflected again by the vehicle to the obstacle and then back to the vehicle. Peak 3 is formed when peak 2 is reflected again by the vehicle to the obstacle and then back to the vehicle. Because the target echo signal and the aftershock signal are superimposed in the near-field environment, the generation and determination of the near-field echo threshold is a challenge in the design and implementation of ultrasonic ranging chips.

[0037] Currently, in the automotive field, the threshold for echo detection is generated using α-β filters or low-pass filters.

[0038] An alpha-beta filter, sometimes called a linear prediction filter, is a simple and effective tool for estimating the motion state of a target. It is particularly suitable for applications requiring short-term predictions of position and velocity. The alpha-beta filter updates the target's position and velocity estimates based on the current position measurement and the state prediction from the previous moment. It adjusts the position and velocity corrections in the prediction using two parameters, α and β. These parameters are typically chosen based on experience or the specific needs of the system. However, it should be noted that parameters α and β cannot be adaptively adjusted during operation.

[0039] A low-pass filter (LPF) is an electronic filter that allows low-frequency signals to pass through while attenuating high-frequency signals. It is used to remove high-frequency noise or unwanted high-frequency components from a signal while retaining the low-frequency portion of the signal.

[0040] For example, Figure 3 , Figure 4 The figures show waveforms of two near-field echo envelope signals processed using alpha filters. It should be noted that the alpha filter is a simplified form of the alpha-beta filter, which simultaneously estimates position and velocity, while the alpha filter primarily focuses on position updates or predictions.

[0041] like Figure 3As shown, the "dashed line" represents the threshold curve generated by the α filter. When the filter sensitivity is set low (i.e., the initial threshold value is high) or the time constant is set large, only the first echo ("1" in the figure) is greater than the corresponding threshold and can be effectively detected; subsequent echoes (such as "2" and "3" in the figure) are difficult to detect. It can be seen that when the initial filter value is large and the sensitivity is low, it is easy to miss alarms.

[0042] like Figure 4 As shown, the "dashed line" still represents the threshold curve generated by the α filter. When the filter sensitivity is set high (i.e., the initial value of the generated threshold is low) or the time constant is set short, especially in the presence of noise, in addition to the expected target echo signal (the "triangle" in the figure) being greater than the corresponding threshold and being effectively detected, it will also lead to a large number of false alarms (the "solid dots" in the figure). That is, when the initial value of the filter is small and the sensitivity is high, false alarms are easy to occur.

[0043] For near-field echo threshold generation, there are two main technical challenges:

[0044] (1) Automatic threshold generation is difficult. On the one hand, the range of near-field echo envelope changes is large and the speed of change is fast. On the other hand, it is difficult to generate thresholds of various forms with fixed parameters. Therefore, it is difficult or impossible to generate near-field thresholds using traditional low-pass filtering, α-β filter and other methods.

[0045] (2) The echo envelope shape during the residual vibration decay stage depends on the resonant characteristics of the ultrasonic transducer and the setting of the peripheral circuit.

[0046] At least one embodiment of this disclosure provides an ultrasonic ranging chip, including an echo signal processing module, a near-field threshold generator, and a near-field decision unit. The echo signal processing module is configured to receive and generate a near-field echo envelope signal based on a target echo signal. The near-field threshold generator is configured to acquire model configuration parameters for a filter and use the filter to predict and generate an adaptive threshold based on the near-field echo envelope signal, wherein the filter gain is adaptively adjusted based on the model configuration parameters and the near-field echo envelope signal. The near-field decision unit is configured to generate a first alarm message based on the near-field echo envelope signal and the adaptive threshold.

[0047] Meanwhile, at least one embodiment of this disclosure also provides an ultrasonic ranging device and an adaptive threshold generation method.

[0048] The ultrasonic ranging chip provided in at least one embodiment of this disclosure fuses the model and measurement values ​​based on the filter model configuration parameters and the near-field echo envelope signal. It uses a prediction method to achieve adaptive threshold generation for near-field (close-range) target detection, effectively reducing the false alarm rate and missed alarm rate of the decision device and achieving accurate detection of near-field targets.

[0049] The present disclosure will now be described in detail with reference to specific embodiments.

[0050] Figure 5 This is a schematic block diagram of an ultrasonic ranging chip provided in at least one embodiment of this disclosure. Figure 5 As shown, the ultrasonic ranging chip 100 includes an echo signal processing module 110, a near-field threshold generator 120, and a near-field decision unit 130.

[0051] The echo signal processing module 110 is configured to receive the target echo signal generated by the ultrasonic transducer and generate a near-field echo envelope signal based on the target echo signal. For example, the echo signal processing module 110 first receives the target echo signal reflected back from the target to be detected by the ultrasonic transducer, and then performs data processing on the target echo signal to generate, for example... Figure 2 The near-field echo envelope signal is a superposition of the target echo signal and the residual vibration signal.

[0052] The near-field threshold generator 120 includes a filter configured to acquire model configuration parameters for the filter and use the filter to predict and generate an adaptive threshold based on the near-field echo envelope signal, wherein the gain of the filter included in the near-field threshold generator is adaptively adjusted based on the model configuration parameters and the near-field echo envelope signal.

[0053] As described above, the alpha filter adjusts based on the difference between the current measurement and the previous prediction. It uses a fixed gain coefficient α to update the estimate, and this gain coefficient α typically needs to be manually set and cannot be adaptively adjusted during testing. Unlike the alpha filter, the filter in the near-field threshold generator 120 in this embodiment can adaptively adjust its gain based on the filter's model configuration parameters and the near-field echo envelope signal. Consequently, the threshold generated using this filter and predicted based on the near-field echo envelope signal is also adaptively adjusted.

[0054] For example, the filter in the near-field threshold generator 120 provided in at least one embodiment of this disclosure can be a Kalman filter, as detailed in the following description. However, it should be noted that the filter in the near-field threshold generator 120 can also be other filters whose gain can be adaptively adjusted based on predicted values, measured values, and system states, and the embodiments of this disclosure do not limit this.

[0055] The near-field decision unit 130 is configured to generate a first alarm message based on the near-field echo envelope signal and an adaptive threshold. For example, when the peak of the near-field echo envelope signal at a certain moment exceeds the adaptively generated threshold at that moment, the near-field decision unit 130 may alert the driver, for example, by issuing an audible alarm or displaying the distance parameters of the near-field target relative to the vehicle on the instrument panel.

[0056] For example, in one possible implementation, the ultrasonic ranging chip 100 further includes a drive controller and a drive circuit. Figure 5 Not shown in the text, see below. Figure 10 The “drive circuit 322” and “digital state machine 321” (where “digital state machine 321” is an example of a drive controller) are configured to send a control signal to the drive circuit, for example, based on a certain emission mode, and the drive circuit is configured to generate a drive signal that conforms to the emission mode based on the control signal, thereby driving the ultrasonic transducer to emit the required ultrasonic waves (e.g., ultrasonic wave groups).

[0057] For example, as described above, the drive controller can be a digital state machine, and the drive signal can be a voltage signal sent to the ultrasonic transducer. The ultrasonic transducer may include a resonant cavity, which may include a transformer, matching capacitors, matching resistors, and piezoelectric devices. The transformer can boost a lower input voltage signal to a higher required voltage level to drive the piezoelectric devices, or conversely, in receiving mode, step down the high-voltage signal for subsequent circuit processing. The matching capacitors and resistors are used to adjust the impedance matching of the entire system to improve energy conversion efficiency and reduce reflection losses. The piezoelectric devices can generate mechanical resonance under the drive of the voltage signal to excite ultrasonic waves, or generate electrical signals under the action of ultrasonic waves.

[0058] For example, the material of the piezoelectric device may include a piezoelectric layer, which may be a piezoelectric ceramic (e.g., barium titanate (BaTiO3), lead zirconate titanate (PZT)), a piezoelectric polymer (e.g., polyvinylidene fluoride (PVDF)) or a single crystal material (e.g., lithium niobate (LiNbO3), lithium tantalate (LiTaO3)). The embodiments disclosed herein are not limited in this respect.

[0059] For example, in one possible implementation, the echo signal processing module 110 includes an echo digital code value generator 1101 and an echo envelope signal generator 1102. The echo digital code value generator 1101 is configured to receive a target echo signal and perform analog-to-digital conversion on the target echo signal to obtain an echo digital code value. The echo envelope signal generator 1102 is configured to receive the echo digital code value and generate a near-field echo envelope signal based on the echo digital code value.

[0060] For example, after the ultrasonic waves excited by the ultrasonic transducer are reflected by the target to be detected after a period of time, they return to the ultrasonic transducer to form a target echo signal. The target echo signal (analog signal) is then converted from analog to digital by the echo digital code value generator 1101 to obtain the echo digital code value (digital signal) and sent to the echo envelope signal generator 1102. The echo envelope signal generator 1102 then generates a near-field echo envelope signal based on the echo digital code value.

[0061] For example, in one possible implementation, the echo digital code value generator 1101 includes an amplifier and an analog-to-digital converter, wherein the amplifier (e.g., a sensitive amplifier) ​​is configured to amplify the target echo signal to obtain an amplified target echo signal; and the analog-to-digital converter is configured to sample the amplified target echo signal and obtain an echo digital code value through analog-to-digital conversion.

[0062] As the propagation distance increases, ultrasonic waves experience energy loss, resulting in very weak echo signals received after being emitted from an ultrasonic transducer and reflected back from an object. The role of an amplifier is to amplify these weak echo signals to a level suitable for processing by subsequent circuitry (e.g., analog-to-digital conversion). Furthermore, in addition to enhancing the useful signal, a high-quality amplifier can effectively reduce internal noise, thereby improving the signal-to-noise ratio (SNR). The analog-to-digital converter (ADC) is responsible for converting the received analog signal into a digital signal for subsequent digital processing and analysis.

[0063] For example, in one possible implementation, the echo envelope signal generator 1102 includes a mixer, a low-pass filter, and an amplitude synthesizer, wherein the mixer is configured to perform frequency conversion on the echo digital code values ​​to obtain echo digital code values ​​of a first frequency; the low-pass filter is configured to filter out high-frequency signals in the echo digital code values ​​of the first frequency to obtain echo digital code values ​​of a second frequency; and the amplitude synthesizer is configured to perform amplitude synthesis on the echo digital code values ​​of the second frequency to obtain a near-field echo envelope signal.

[0064] For example, if it is necessary to process ultrasonic signals of different frequencies, or if it is necessary to convert the received high-frequency signal (echo digital code value) into a lower intermediate frequency signal (echo digital code value of the first frequency) for the convenience of subsequent processing, a mixer can be used to achieve this purpose.

[0065] For example, a low-pass filter can remove high-frequency noise and unwanted high-frequency components from the echo digital code value at the first frequency, ensuring signal purity and measurement accuracy. Furthermore, besides noise removal, a low-pass filter can smooth the signal, especially when processing signals that may fluctuate or exhibit irregular changes. A properly designed low-pass filter can help eliminate these fluctuations, providing a more stable signal output and facilitating more accurate distance calculations.

[0066] The amplitude synthesizer first detects the amplitude of the echo digital code value at the second frequency, and then combines this amplitude with the residual resonant signal of the high-energy wave transducer to obtain, for example... Figure 2 The near-field echo envelope signal is shown.

[0067] For example, in one possible implementation, the ultrasonic ranging chip 100 further includes a decay time measurement module (not shown) configured to acquire the decay phase of the ultrasonic transducer. This module measures the time from the start of wave emission until the ultrasonic transducer's oscillation amplitude decays to a specific threshold, typically set via a register. The time measurement is based on counting clock signals during chip operation. For example, the decay time measurement module is electrically connected to the ultrasonic transducer and acquires a clock signal from the chip to detect the decay phase of the ultrasonic transducer. This detection can be performed by the ultrasonic chip at predetermined time intervals (e.g., every time the chip is powered on or every predetermined time interval (e.g., 1 hour)). The filter's model configuration parameters include the decay phase, the analog-to-digital converter's sampling time interval, the observation matrix, the system model confidence level, and the observation confidence level. For example, as... Figure 1 The time corresponding to the "aftershock process" shown is the aftershock time. For example, the observation matrix is ​​used to map the system's state vector to the observation space, that is, it defines how to calculate the expected observations from the system's true state.

[0068] In at least one embodiment of this disclosure, the system's state vector and the observations can be understood as near-field echo envelope signals. The corresponding observation matrix can, for example, take a value of 1, indicating that the observation model considers the near-field echo envelope signal obtained by the amplitude synthesizer to be accurate, without any gain or attenuation. It should be noted that the observation matrix (or an element in the observation matrix) can also take other values, depending on the choice of the observations, and the embodiments of this disclosure do not limit this.

[0069] System model confidence reflects a measure of the uncertainty of the system model, describing the uncertainty of state changes during the prediction process. A higher value indicates a lower level of confidence in the system model.

[0070] Observation confidence level indicates the magnitude of noise during the observation process, i.e., the uncertainty of sensor readings. A higher value means a lower level of confidence in the measurement data (i.e., the observations).

[0071] For example, in one possible implementation, the ultrasonic ranging chip 100 further includes a data storage unit (not shown) configured to receive and store model configuration parameters of the filter, wherein the near-field threshold generator is further configured to obtain the stored model configuration parameters from the data storage unit.

[0072] For example, the data storage unit can be a register or a memory (e.g., a semiconductor memory). The user can store the model configuration parameters required for the filter in the register or memory in advance through the host computer, and the near-field threshold generator 120 can call the required mode configuration parameters from the register or memory during the threshold generation process.

[0073] For example, in one possible implementation, the filter is a Kalman filter, whose state transition equation is a linear equation, obtained by the following formula:

[0074]

[0075] Where F is the state transition equation, Ts is the sampling time interval of the analog-to-digital converter, and τ reg For the remaining time.

[0076] Figure 6 The flowchart for generating a near-field echo threshold based on a Kalman filter, provided for at least one embodiment of this disclosure, specifically includes steps S201 to S209.

[0077] Step S201: The digital state machine loads configuration parameters from registers or memory. The configuration parameters include the sampling time interval Ts of the analog-to-digital converter and the residual oscillation time τ. reg Observation matrix H, system model credibility Q reg and the observation confidence level R reg .

[0078] Unlike traditional Kalman filters where the state transition equation F is derived from a physical model (e.g., in navigation, where velocity = integral of acceleration over time is often chosen as the state transition equation F), the state transition equation F of at least one embodiment of this disclosure depends on the ultrasonic transducer (residual vibration time τ). reg The matching circuit parameters (sampling time interval Ts of the analog-to-digital converter) are calculated using the following formula (1):

[0079] (1)

[0080] Among them, the sampling time interval Ts and the residual oscillation time τ of the analog-to-digital converter reg It needs to be obtained through prior measurements and stored in a register or memory for later retrieval. Similarly, the state transition equation of the system model can also be written as formula (1-1):

[0081] (1-1)

[0082] Where V(t) represents the voltage across the ultrasonic transducer measured at time t, and V(t+1) represents the voltage across the ultrasonic transducer measured at the next time t. Here, t is the sampling time of the internal analog-to-digital converter, and t+1 represents the next sampling time of the analog-to-digital converter.

[0083] Step S202: The digital state machine obtains the envelope value Envelope[t] from the amplitude synthesizer. This envelope value Envelope[t] is the near-field echo envelope value.

[0084] Step S203: Use the envelope value Envelope[t] as the measurement variable z[t], i.e., z[t] = Envelope[t]. For example, this measurement variable is the observation.

[0085] Step S204: Update the Kalman gain K[t] using the following formula (2):

[0086] (2)

[0087] Where P is the process covariance (representing the uncertainty of the state model). The prior estimate / prediction of the process covariance is represented by H, where H represents the observation matrix and R is the covariance matrix of the observation noise (representing the noise level present during the observation process, i.e., reflecting the inaccuracy of sensor readings).

[0088] Step S205: Calculate the residual e[t] using the following formula (3):

[0089] (3)

[0090] Where x is a state variable, specifically a threshold in the embodiments of this disclosure; This represents the prior estimate / prediction of the threshold.

[0091] Step S206: Update the state variables and process error using the following formulas (4) and (5):

[0092] (4)

[0093] (5)

[0094] in, This represents the posterior estimate of the threshold, i.e., the optimal estimate after correction based on the measured value; This represents the posterior estimate of the process covariance, i.e., the optimal estimate after correction of the measured values.

[0095] Step S207: Predict the state variables and process errors for the next step using the following formulas (6) and (7):

[0096] (6)

[0097] (7)

[0098] Where Q is Q in step S201 reg .

[0099] Step 208: Use the predicted value as the threshold Threshold[t+1], and calculate it using the following formula (8):

[0100] (8)

[0101] in, Indicates the threshold gain when used. This indicates a mismatch during use.

[0102] Step S209: The digital state machine transmits the threshold Threshold[t+1] to the near-field decision unit and generates alarm information based on the near-field echo envelope signal.

[0103] Figure 7 This is a near-field echo threshold waveform generated based on a Kalman filter, provided for at least one embodiment of this disclosure. (See also:) Figure 7 As shown, the dashed line represents the Kalman single-step prediction value (i.e., the generated adaptive threshold), and the solid line represents the near-field echo envelope signal. It can be seen that within the near-field range, the threshold generated based on the Kalman filter is adaptively adjusted according to the near-field echo envelope signal. All three peaks of the target echo signal contained in the superimposed signal can exceed the adaptively generated threshold and be detected normally.

[0104] The ultrasonic ranging chip provided in at least one embodiment of this disclosure fuses the model and measurement values ​​based on the filter model configuration parameters and the near-field echo envelope signal. It uses a prediction method to achieve adaptive threshold generation for near-field (close-range) target detection, effectively reducing the false alarm rate and missed alarm rate of the decision device and achieving accurate detection of near-field targets.

[0105] For example, in one possible implementation, when the intensity of the ultrasonic signal emitted by the ultrasonic transducer decreases inversely with the square of the transmission distance, the state transition equation of the filter is a nonlinear equation, wherein the filter is an extended Kalman filter or an unscented Kalman filter, configured to linearize the state transition equation; or, the filter is a particle filter, configured to linearize the state transition equation.

[0106] When more factors affecting the threshold are introduced, such as the influence of residual resonance time, it is also necessary to consider that the intensity of the ultrasonic signal excited by the ultrasonic transducer decreases inversely with the square of the transmission distance. In this case, the state transition equation becomes a nonlinear equation, and it is necessary to use, for example, an extended Kalman filter to linearize this nonlinear equation before performing the subsequent adaptive threshold generation step. That is, based on the above linear state transition equation (1-1), the nonlinear state transition equation is specifically the following formula (1-2):

[0107] (1-2)

[0108] Then, by taking the Jacobian matrix of formula (1-2) and performing first-order linearization, the state transition matrix of the extended Kalman filter can be obtained. Specifically, it is calculated using the following formula (1-3):

[0109] (1-3)

[0110] At this point, the flowchart for generating the near-field echo threshold based on the extended Kalman filter is as follows: Figure 8 As shown.

[0111] and Figure 6 Compared to the near-field echo threshold generated based on the Kalman filter, the near-field echo threshold generated based on the extended Kalman filter differs in that: in the calculation of predicting the next state variable and process error, the constant F in formula (1) is no longer used, but formulas (1-2) and (1-3) are used, specifically calculated through the following formulas (9), (10), and (11):

[0112] (9)

[0113] (10)

[0114] (11)

[0115] At least one embodiment of this disclosure comprehensively considers multiple factors affecting threshold generation and linearizes the system state transition equation based on, for example, an extended Kalman filter, so that the threshold generated in the near field range is more in line with actual needs, thereby achieving accurate detection of near-field targets.

[0116] It should be noted that, in the case of handling the nonlinear state transition equation described above, an unscented Kalman filter can also be used to linearize the nonlinear state transition equation. The difference between the unscented Kalman filter and the extended Kalman filter is that the unscented Kalman filter does not directly linearize the nonlinear function. Instead, it selects a series of deterministic sampling points (called Sigma points), which are chosen around the probability distribution of the current state. These Sigma points are then passed through the nonlinear function, and the state and covariance are re-estimated based on the transformed Sigma points, thus achieving the linearization of the nonlinear function. The extended Kalman filter, on the other hand, calculates the Jacobian matrix of the nonlinear function for linearization, but the methods for generating adaptive thresholds are essentially the same. Those skilled in the art will understand that an unscented Kalman filter can also be used to achieve adaptive threshold generation in nonlinear cases.

[0117] Similarly, nonlinear state transition equations can also be linearized based on particle filters, and the embodiments of this disclosure are not limited in this regard.

[0118] For example, in one possible implementation, the ultrasonic ranging chip provided in at least one embodiment of this disclosure further includes a far-field threshold generator and a far-field decision unit, wherein the echo signal processing module is further configured to receive and generate a far-field echo envelope signal based on the target echo signal, wherein the far-field threshold generator is configured to generate a first threshold based on the far-field echo envelope signal; and the far-field decision unit is configured to generate a second alarm message based on the far-field echo envelope signal and the first threshold.

[0119] For example, the above Figure 5 The ultrasonic ranging chip 100 shown may also include a far-field threshold generator and a far-field decision unit. Figure 5 Not shown in the text, see below. Figure 10 The target echo signal includes not only the beam signal reflected from the near-field target but also the beam signal reflected from the far-field target. Since the far-field target is farther away from the ultrasonic probe, there is no superposition with the residual vibration signal of the ultrasonic transducer; that is, the peak of the target echo signal from the far field can be displayed. Figure 1 During the distance measurement process shown, the far-field threshold generator can directly generate a far-field threshold based on the far-field echo envelope signal, for example, using an α-β filter or a low-pass filter. The far-field decision unit then generates a second alarm message based on the set far-field threshold and the far-field echo envelope signal.

[0120] For example, the second alarm message is the same as the first alarm message mentioned above. Based on the alarm message, it can be used to determine how to perform subsequent operations, such as displaying the distance information of the far-field target from the vehicle on the dashboard or main control screen.

[0121] At least one embodiment of this disclosure also provides an ultrasonic ranging device, including an ultrasonic transducer and an ultrasonic ranging chip in any of the above embodiments, wherein the ultrasonic transducer is configured to receive a drive signal from the ultrasonic ranging chip to emit ultrasonic waves, and to receive reflected ultrasonic waves to obtain a target echo signal.

[0122] Figure 9 This is a schematic block diagram of an ultrasonic ranging device provided for at least one embodiment of the present disclosure. Figure 9 As shown, the ultrasonic ranging device 200 includes an ultrasonic ranging chip 210 and an ultrasonic transducer 220. For example, the ultrasonic ranging chip 210 includes the ultrasonic ranging chip provided in any of the above embodiments, and the specific description of the ultrasonic ranging chip will not be repeated here. The ultrasonic transducer 220 is also the ultrasonic transducer in at least one of the above embodiments, and its specific function is described above, and will not be repeated here.

[0123] Figure 10 An example of an ultrasonic ranging device provided for at least one embodiment of this disclosure.

[0124] like Figure 10 As shown, the ultrasonic ranging device includes an ultrasonic ranging chip 300 and an ultrasonic transducer 310 (highlighted by a dashed line in the figure). The ultrasonic transducer 310, from right to left, includes a transformer 3101, a matching capacitor 3102, a matching resistor 3103, and a piezoelectric device 3104. In the ultrasonic transducer 310, the transformer 3101, matching capacitor 3102, matching resistor 3103, and piezoelectric device 3104 are connected in parallel.

[0125] The ultrasonic ranging chip 300 mainly includes an echo signal processing module 330, a near-field threshold generator 316 (shown by a dashed line in the figure), a near-field decision unit 316, and other necessary circuits or modules for ultrasonic ranging. The echo signal processing module 330 includes an echo digital code value generator 331 and an echo envelope signal generator 332 (shown by a dashed line in the figure). The echo digital code value generator 331 includes an amplifier 311 and an analog-to-digital converter 312, while the echo envelope signal generator 332 includes a mixer 313, a low-pass filter 314, and an amplitude synthesizer 315.

[0126] For example, digital state machine 321 is electrically connected to drive circuit 322 and controls drive circuit to send drive signal to transformer 3101. Ultrasonic transducer 310 is electrically connected to amplifier 311 to transmit target echo signal. Amplifier 311 is electrically connected to analog-to-digital converter 312 to transmit amplified target echo signal to analog-to-digital converter 312 for analog-to-digital conversion to generate digital signal. Analog-to-digital converter 312 is then electrically connected to mixer 313 to send the digital signal to mixer 313 to process the frequency of target echo signal. Mixer 313 is then electrically connected to low-pass filter 314 to filter out high-frequency noise in target echo signal. Low-pass filter 314 is then electrically connected to amplitude synthesizer 315 to divide the processed target echo signal into near-field echo envelope signal and far-field echo envelope signal.

[0127] Amplitude synthesizer 315 is electrically connected to near-field threshold generator 316 to send near-field echo envelope signals, and to far-field threshold generator 318 to send far-field echo envelope signals. Near-field threshold generator 316 is also electrically connected to register 320 to retrieve stored model configuration parameters. After generating the corresponding thresholds, near-field threshold generator 316 and far-field threshold generator 318 are electrically connected to near-field decision unit 317 and far-field decision unit 319 respectively to obtain alarm information in the near and far fields. Post-processing module 324 is then electrically connected to near-field decision unit 317 and far-field decision unit 319 to process the alarm information and send it to controller 328. Controller 328 and communication module 329 can communicate bidirectionally to control the overall testing process of the ultrasonic ranging device.

[0128] Here, for example, the power module 325, the clock module 326, and the memory 327 are all independent modules. The power module 325 is used to provide the power supply required by the ultrasonic ranging device, the clock module 326 is used to uniformly manage the data clock of each component, and the memory 327 is used to store the corresponding calculation data.

[0129] The specific testing process is explained below.

[0130] Before the test begins, the residual vibration time measurement module 323 measures and records the residual vibration time of the piezoelectric device 3104 in the register 320, and the sampling time interval of the analog-to-digital converter 312 is also recorded in the register 320 at the same time.

[0131] After the test begins, the digital state machine 321 sends a specific pulse signal to the drive circuit 322. The drive circuit 322 generates a power drive signal (e.g., a voltage signal). This drive signal is sequentially boosted by the transformer (e.g., a step-up transformer) injected into the ultrasonic transducer 310. After impedance matching is achieved through the combined action of the matching capacitor 3102 and the matching resistor 3103, it acts on the piezoelectric device 3104 to generate mechanical resonance, thereby exciting an ultrasonic signal. This ultrasonic signal is transmitted in the environment and reflected back to the ultrasonic transducer after being reflected by the target to obtain the target echo signal. The target echo signal is first sent to the amplifier 311 for signal amplification, and then converted into a digital signal by the analog-to-digital converter 312 for subsequent device processing and analysis.

[0132] Specifically, the echo digital signal undergoes frequency conversion and high-frequency noise filtering via mixer 313 and low-pass filter 314, and then is processed by amplitude synthesizer 315 to generate near-field echo envelope signals and far-field echo envelope signals. The near-field echo envelope signal is input to near-field threshold generator 316 to generate an adaptive threshold for the near-field range. This adaptive threshold, along with the data from the near-field echo envelope signal, is then sent to near-field decision unit 317 to generate corresponding near-field alarm information. Simultaneously, the far-field echo envelope signal is input to far-field threshold generator 318 to directly generate a threshold for the far-field range. This threshold, along with the data from the far-field echo envelope signal, is then sent to far-field decision unit 319 to generate corresponding far-field alarm information.

[0133] The post-processing module 324 performs comprehensive processing on the alarm information output by the near-field decision device 317 and the far-field decision device 319 (for example, calculating the specific distances of the near-field and far-field targets relative to the vehicle using the time-of-flight method) and then sends it to the controller 328. The communication module 329 (e.g., an external computer) can communicate bidirectionally with the controller 329 so that the user can issue relevant control signals.

[0134] For example, in addition to the devices mentioned above, an ultrasonic ranging chip may also include a power module, a clock module, and memory. These modules are general-purpose modules in the chip, and their specific functions will not be elaborated here.

[0135] It should be noted that, for clarity and brevity, the embodiments of this disclosure do not show all the constituent units of the ultrasonic ranging system. To achieve the necessary functions of the ultrasonic ranging system, those skilled in the art can provide and set other constituent units (not shown) according to specific needs, and the embodiments of this disclosure do not impose any limitations on this.

[0136] At least one embodiment of this disclosure also provides a device including any of the above-described ultrasonic ranging devices. For example, the device can be an electronic device. For instance, the ultrasonic ranging device can be encapsulated within a miniature metal or high-strength engineering plastic housing to form an embedded ultrasonic ranging sensor, such as a reversing radar probe, thereby integrating it into a vehicle (e.g., a car, truck, etc.). As another example, the ultrasonic ranging device can also be encapsulated in the joint of a robotic arm or the end effector of a mobile mechanical device such as an industrial robot. The embodiments of this disclosure do not limit the specific application scenarios of the device.

[0137] At least one embodiment of this disclosure also provides a method for generating an adaptive threshold, applied to near-field echo detection in an ultrasonic ranging chip, comprising: generating a near-field echo envelope signal based on a target echo signal; obtaining model configuration parameters for a filter; using the filter to predict and generate an adaptive threshold based on the near-field echo envelope signal, wherein the gain of the filter is adaptively adjusted based on the model configuration parameters and the near-field echo envelope signal; and generating alarm information based on the near-field echo envelope signal and the adaptive threshold.

[0138] Figure 11 A flowchart of an adaptive threshold generation method provided for at least one embodiment of the present disclosure includes steps S410-430.

[0139] Step S410: Generate a near-field echo envelope signal based on the target echo signal generated by the ultrasonic transducer.

[0140] Step S420: Obtain the model configuration parameters for the filter, and use the filter to predict and generate an adaptive threshold based on the near-field echo envelope signal, wherein the filter gain is adaptively adjusted based on the model configuration parameters and the near-field echo envelope signal.

[0141] Step S430: Generate alarm information based on the near-field echo envelope signal and the adaptive threshold.

[0142] For step S410, this step can be implemented, for example, by the ultrasonic transducer, amplifier, analog-to-digital converter, mixer, low-pass filter and amplitude synthesizer mentioned above. The specific operation steps will not be described in detail here.

[0143] For step S420, this step can be implemented, for example, by the near-field threshold generator described above. The specific operation steps will not be repeated here.

[0144] For step S430, this step can be implemented by the near-field decision device mentioned above, and the specific operation steps will not be repeated here.

[0145] For example, in one possible implementation, the adaptive threshold generation method provided in at least one embodiment of this disclosure further includes: acquiring the residual vibration time of the ultrasonic transducer, wherein the model configuration parameters include the residual vibration time, the sampling time interval of the analog-to-digital converter, the observation matrix, the system model confidence level, and the observation confidence level. For example, this step can be implemented by the residual vibration time measurement module described above, and the model configuration parameters have been described in detail above, and will not be repeated here.

[0146] For example, in one possible implementation, the filter is a Kalman filter, whose state transition equation is a linear equation, obtained by the following formula:

[0147]

[0148] Where F is the state transition equation, Ts is the sampling time interval of the amplified target echo signal, and τ reg For the remaining time.

[0149] For details on this step, please refer to the description of the Kalman filter above; it will not be repeated here.

[0150] The adaptive threshold generation method for near-field echo detection provided in at least one embodiment of this disclosure is based on the filter model configuration parameters and the measured value of the near-field echo envelope signal. It fuses the model and the measured value and uses a prediction method to realize adaptive threshold generation for near-field (close-range) target detection, effectively reducing the false alarm rate and missed alarm rate of the decision device and achieving accurate detection of near-field targets.

[0151] Although the present disclosure has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to the embodiments of the present disclosure, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present disclosure are within the scope of protection claimed by the present disclosure.

[0152] The following points should be noted regarding this disclosure:

[0153] (1) The accompanying drawings of the embodiments of this disclosure only involve the structures involved in the embodiments of this disclosure. Other structures can be referred to the general design.

[0154] (2) For clarity, the thickness of layers or regions in the drawings used to describe embodiments of the present disclosure is enlarged or reduced, i.e., these drawings are not drawn to actual scale.

[0155] (3) Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0156] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. The scope of protection of this disclosure should be determined by the scope of protection of the claims.

Claims

1. An ultrasonic ranging chip, comprising an echo signal processing module, a near-field threshold generator, and a near-field decision unit, wherein, The echo signal processing module is configured to receive the target echo signal generated by the ultrasonic transducer and generate a near-field echo envelope signal based on the target echo signal. The near-field threshold generator includes a filter, and is configured to acquire model configuration parameters for the filter, and use the filter to predict and generate an adaptive threshold based on the near-field echo envelope signal, wherein the gain of the filter is adaptively adjusted based on the model configuration parameters and the near-field echo envelope signal; and The near-field decision device is configured to generate a first alarm message based on the near-field echo envelope signal and the adaptive threshold.

2. The ultrasonic ranging chip according to claim 1 further includes a drive controller and a drive circuit, wherein, The drive controller is configured to send pulse signals to the drive circuit; The driving circuit is configured to generate a driving signal based on the pulse signal to drive the ultrasonic transducer.

3. The ultrasonic ranging chip according to claim 1, wherein, The echo signal processing module includes an echo digital code value generator and an echo envelope signal generator, wherein, The echo digital code value generator is configured to receive the target echo signal and perform analog-to-digital conversion on the target echo signal to obtain the echo digital code value. The echo envelope signal generator is configured to receive the echo digital code value and generate the near-field echo envelope signal based on the echo digital code value.

4. The ultrasonic ranging chip according to claim 3, wherein, The echo digital code value generator includes an amplifier and an analog-to-digital converter, wherein, The amplifier is configured to amplify the target echo signal to obtain an amplified target echo signal; The analog-to-digital converter is configured to sample the amplified target echo signal and then obtain the echo digital code value through analog-to-digital conversion.

5. The ultrasonic ranging chip according to claim 4, wherein, The echo envelope signal generator includes a mixer, a low-pass filter, and an amplitude synthesizer, wherein... The mixer is configured to perform frequency conversion on the echo digital code value to obtain an echo digital code value at a first frequency. The low-pass filter is configured to filter out high-frequency signals in the echo digital code value of the first frequency to obtain the echo digital code value of the second frequency; and The amplitude synthesizer is configured to perform amplitude synthesis of the echo digital code values ​​of the second frequency to obtain the near-field echo envelope signal.

6. The ultrasonic ranging chip according to claim 5 further includes a residual vibration time measurement module, wherein the residual vibration time measurement module is configured to acquire the residual vibration time of the ultrasonic transducer. The model configuration parameters include the residual oscillation time, the sampling time interval of the analog-to-digital converter, the observation matrix, the system model confidence level, and the observation confidence level.

7. The ultrasonic ranging chip according to claim 6, wherein, The filter is a Kalman filter, and the state transition equation of the Kalman filter is a linear equation, obtained through the following formula: ； Where F is the state transition equation, Ts is the sampling time interval of the analog-to-digital converter, and τ reg The residual vibration time is denoted as .

8. The ultrasonic ranging chip according to claim 6, wherein, When the intensity of the ultrasonic signal emitted by the ultrasonic transducer decreases inversely with the square of the transmission distance, the state transition equation of the filter is a nonlinear equation, wherein, The filter is an extended Kalman filter or an unscented Kalman filter, configured to linearize the state transition equation, or... The filter is a particle filter, configured to linearize the state transition equation.

9. The ultrasonic ranging chip according to claim 1, further comprising: The data storage unit is configured to receive and store the model configuration parameters. The near-field threshold generator is further configured to obtain the stored model configuration parameters from the data storage unit.

10. The ultrasonic ranging chip according to any one of claims 1-9 further includes a far-field threshold generator and a far-field decision unit, wherein, The echo signal processing module is further configured to receive and generate a far-field echo envelope signal based on the target echo signal, wherein... The far-field threshold generator is configured to generate a first threshold based on the far-field echo envelope signal; The far-field decision device is configured to generate a second alarm message based on the far-field echo envelope signal and the first threshold.

11. An ultrasonic ranging device, comprising an ultrasonic transducer and the ultrasonic ranging chip according to any one of claims 1-10, in, The ultrasonic transducer is configured to receive a drive signal from the ultrasonic ranging chip to emit ultrasonic waves, and to receive the reflected ultrasonic waves to obtain the target echo signal.

12. An adaptive threshold generation method applied to the ultrasonic ranging chip according to any one of claims 1-10, comprising: A near-field echo envelope signal is generated based on the target echo signal produced by the ultrasonic transducer. Obtain model configuration parameters for the filter, and use the filter to predict and generate an adaptive threshold based on the near-field echo envelope signal, wherein the gain of the filter is adaptively adjusted based on the model configuration parameters and the near-field echo envelope signal; as well as Alarm information is generated based on the near-field echo envelope signal and the adaptive threshold.

13. The adaptive threshold generation method according to claim 12, further comprising: Obtain the residual vibration time of the ultrasonic transducer, wherein, The model configuration parameters include the residual oscillation time, the sampling time interval of the analog-to-digital converter, the observation matrix, the system model confidence level, and the observation confidence level.

14. The adaptive threshold generation method according to claim 13, wherein, The filter is a Kalman filter, and the state transition equation of the Kalman filter is a linear equation, obtained through the following formula: ； Where F is the state transition equation, Ts is the sampling time interval of the analog-to-digital converter, and τ reg The residual vibration time is denoted as .

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