Phase detection mobile object based on channel impulse response

Abstract

A mobile object detector detects a mobile object in a channel. The detection includes the detector receiving a plurality of frames based on a transmitter transmitting the plurality of frames through the channel. One or more channel impulse responses (CIRs) of the channel are determined based on the received plurality of frames. The detector determines a CIR phase of each of the CIRs, and a phase signal is formed based on phase values of the CIR phase of each of the CIRs. The detector compares the phase signal to a target signal, and detects the mobile object in the channel based on the comparison.

Description

Technical Field

[0001] This disclosure generally relates to moving object detection, and more specifically, to phase detection of moving objects based on channel impulse response. Background Technology

[0002] Existing sensor technology measures the distance between a transceiver, such as a remote key carried by a person, and a vehicle, enabling the vehicle to be unlocked when the person approaches. This sensor technology also utilizes the Doppler effect to provide motion information, thus being able to sense a leg kick at the rear bumper of the vehicle, indicating that the person intends to open the trunk or to detect the vital signs of passengers inside the vehicle, such as respiratory rate and heart rate. Summary of the Invention

[0003] According to one aspect of the present invention, a method for detecting a moving object is provided, the method comprising:

[0004] Multiple frames transmitted through the channel are received using a moving object detector;

[0005] The detector determines one or more channel impulse responses (CIRs) associated with the channel based on multiple received frames;

[0006] The CIR phase of each of the CIRs is determined by the detector;

[0007] A phase signal is formed by the detector based on the phase value of the CIR phase of each of the CIRs;

[0008] The phase signal is compared with the target signal using the detector; and

[0009] The detector detects the moving object in the channel based on the comparison.

[0010] According to one or more embodiments, the phase value of the CIR phase of each of the phase signals is located at the same time position in each of the CIR phases.

[0011] According to one or more embodiments, the CIR phase and the phase signal define a phase value that varies with time.

[0012] According to one or more embodiments, forming the phase signal includes: forming a first candidate phase signal and a second candidate phase signal, wherein the first candidate phase signal is associated with a phase value located only at a first time position in each of the CIR phases, and the second candidate phase signal is associated with a phase value located only at a second time position in each of the CIR phases; and selecting the first candidate phase signal or the second candidate phase signal as the phase signal based on a corresponding amplitude or power associated with the first candidate phase signal or the second candidate phase signal exceeding a threshold level.

[0013] According to one or more embodiments, the target signal defines a phase value that varies over time, the phase value indicating a kick toward the vehicle, and wherein detecting the moving object includes detecting the kick toward the vehicle.

[0014] According to one or more embodiments, the target signal defines a phase value that varies over time, the phase value indicating human vital signs, and wherein detecting the moving object includes detecting the human's vital signs.

[0015] According to one or more embodiments, the target signal includes a phase value that varies over time, the phase value representing the moving object.

[0016] According to one or more embodiments, detecting the moving object in the channel includes determining that the correlation between the target signal and the phase signal exceeds a threshold level.

[0017] According to one or more embodiments, detecting the moving object in the channel includes providing the speed of the moving object based on the amplitude of the phase signal.

[0018] According to one or more embodiments, determining the one or more CIRs by the detector includes associating one or more pulses of a pulse sequence of received frames with one or more expected pulses, and the method further includes transmitting multiple frames through the channel, wherein the format and content of the multiple transmitted frames are defined by the Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 standard.

[0019] According to a second aspect of the present invention, a moving object detector is provided, comprising:

[0020] Analog / digital front end, which is implemented using circuitry to receive multiple frames from a channel;

[0021] A CIR estimator, implemented with a circuit system, determines one or more CIRs of the channel based on multiple received frames;

[0022] A phase extractor, implemented with a circuit system, determines the CIR phase of each of the CIRs and forms a phase signal based on the phase value of the CIR phase of each of the CIRs; and

[0023] An object detector is implemented using a circuit system to compare the phase signal with a target signal and detect the moving object in the channel based on the comparison.

[0024] According to one or more embodiments, the phase value of the CIR phase of each of the phase signals is located at the same time position in each of the CIR phases.

[0025] According to one or more embodiments, the CIR phase and the phase signal have phase values ​​that vary with time.

[0026] According to one or more embodiments, the phase extractor for forming the phase signal includes: a circuit system for forming a first candidate phase signal and a second candidate phase signal, wherein the first candidate phase signal is associated with a phase value located only at a first time position in each of the CIR phases, and the second candidate phase signal is associated with a phase value located only at a second time position in each of the CIR phases; and a circuit system for selecting the first candidate phase signal or the second candidate phase signal as the phase signal based on a corresponding amplitude or power associated with the first candidate phase signal or the second candidate phase signal exceeding a threshold level.

[0027] According to one or more embodiments, the target signal defines a phase value that varies over time and is associated with a kick toward the vehicle, and wherein the object detector for detecting the moving object includes a circuitry for detecting the kick toward the vehicle.

[0028] According to one or more embodiments, the target signal defines a phase value that varies over time and is associated with human vital signs, and wherein the object detector for detecting the moving object includes a circuit system for detecting the human's vital signs.

[0029] According to one or more embodiments, the target signal includes a phase value that varies over time, the phase value representing the moving object.

[0030] According to one or more embodiments, the object detector for detecting the moving object in the channel includes a circuit system for determining that the correlation between the target signal and the phase signal exceeds a threshold level.

[0031] According to one or more embodiments, the object detector for detecting the moving object in the channel includes a circuit system for providing the speed of the moving object based on the phase signal.

[0032] According to one or more embodiments, the detector further includes a transmitter implemented with a circuit system to transmit multiple frames over the channel, wherein the IEEE 802.15.4 standard defines the format and content of the multiple transmitted frames. Attached Figure Description

[0033] Figure 1 This is an example block diagram of a moving object detector used to detect moving objects.

[0034] Figure 2 The method for generating phase signals by a moving object detector is shown in more detail.

[0035] Figures 3A-3C An example phase signal is shown, determined by a person making multiple accelerated kicks to a moving object detector mounted on the rear bumper of a vehicle.

[0036] Figures 4A-4B The example demonstrates the detection of vital signs, such as a person's heart rate or respiratory rate, based on a sample phase signal.

[0037] Figure 5 This is an example flowchart of the functionality associated with detecting moving objects through a moving object detector.

[0038] Figure 6 This is a block diagram of an example device used to detect moving objects.

[0039] The drawings are for illustrative purposes only, but it should be understood that the embodiments are not limited to the arrangements and means shown in the drawings. Detailed Implementation

[0040] The following description includes example systems, methods, techniques, and procedure flows for moving object detection, and more specifically, moving objects are detected based on the channel impulse response (CIR) of the channel and, in particular, on the time-domain representation of the CIR phase. In the example, the CIR is determined by transmitting radio frequency (RF) pulses and receiving RF pulses based on the transmitted RF pulses reflected from the moving object. A phase signal with a phase value varying over time is determined based on the time-domain representation of the CIR phase. The phase signal is then compared with a target signal to detect the moving object. Since the CIR is not converted to the frequency domain, such as a Fast Fourier Transform (FFT) of the CIR, detection is performed in the time domain with low power consumption and low memory requirements. To avoid obfuscation, well-known instructions, protocols, structures, and techniques are not shown in detail.

[0041] Example System

[0042] Figure 1This is an example block diagram of a moving object detector 100 for detecting moving objects. The moving object detector 100 may include one or more components, such as a transmitter 102, an analog / digital front-end 104, a channel impulse response detector 122, a CIR estimator 124, a CIR preprocessor 126, a phase processing system 128, a phase extractor 130, and an object detector 132. The transmitter 102 may be implemented using circuit systems such as analog circuit systems, mixed-signal circuit systems, memory circuit systems, logic circuit systems, and / or processing circuit systems, which execute code stored in memory, and when executed by the processing circuit system, this code performs the disclosed functions of the transmitter 102. The analog / digital front-end 104 may be implemented using circuit systems such as analog circuit systems, mixed-signal circuit systems, memory circuit systems, logic circuit systems, and / or processing circuit systems, which execute code stored in memory, and when executed by the processing circuit system, this code performs the disclosed functions of the analog / digital front-end 104. The channel impulse response detector 122 can be implemented using circuit systems such as analog circuit systems, mixed-signal circuit systems, memory circuit systems, logic circuit systems, and / or processing circuit systems. These circuit systems execute code stored in memory, which, when executed by the processing circuit system, performs the disclosed functions of the channel impulse response detector 122. The CIR estimator 124 can be implemented using circuit systems such as analog circuit systems, mixed-signal circuit systems, memory circuit systems, logic circuit systems, and / or processing circuit systems. These circuit systems execute code stored in memory, which, when executed by the processing circuit system, performs the disclosed functions of the CIR estimator 124. The CIR preprocessor 126 can be implemented using circuit systems such as analog circuit systems, mixed-signal circuit systems, memory circuit systems, logic circuit systems, and / or processing circuit systems. These circuit systems execute code stored in memory, which, when executed by the processing circuit system, performs the disclosed functions of the CIR preprocessor 126. The phase processing system 128 can be implemented using circuit systems such as analog circuit systems, mixed-signal circuit systems, memory circuit systems, logic circuit systems, and / or processing circuit systems. These circuit systems execute code stored in memory, which, when executed by the processing circuit system, performs the disclosed functions of the phase processing system 128. The phase extractor 130 can be implemented using circuit systems such as analog circuit systems, mixed-signal circuit systems, memory circuit systems, logic circuit systems, and / or processing circuit systems. These circuit systems execute code stored in memory, which, when executed by the processing circuit system, performs the disclosed functions of the phase extractor 130.The object detector 132 can be implemented using circuit systems such as analog circuit systems, mixed-signal circuit systems, memory circuit systems, logic circuit systems, and / or processing circuit systems, which execute code stored in memory. When executed by the processing circuit system, this code performs the disclosed functions of the object detector 132. In some embodiments, some of the components can be implemented using the same circuit system, such as the same processing circuit system executing different sets of code. The components can also be implemented in other ways.

[0043] In this example, the moving object detector 100 can detect a moving object 106 in channel 108 based on processing of the received transmitted channel impulse response (CIR) from channel 108. CIR represents the channel response, which is generated by the transmission antenna 142 of transmitter 102 transmitting a pulse sequence 112 and the receiving antenna 120 of analog / digital front end 104 receiving a pulse sequence 154 through channel 108 based on the transmitted pulse sequence 112. Channel 108 can be a transmission medium, such as air for the transmitted and received pulses. Furthermore, channel 108 can have one or more objects, such as moving object 106 and static object 118. The object can be a physical structure, and in some examples, the object can be a part of a larger object. In one example, a person or a person's limb can be an object, and the object is a moving object when the person is gesturing with their limb, and a static object when the limb is stationary. In another example, a car can be an object, and the object is a moving object when the car is moving, and a static object when the car is stationary. Moving object 106 and stationary object 118 may affect the CIR due to reflections of the transmitted pulse sequence 112 away from one or more objects in channel 108, such as moving object 106 and any stationary object 118. For example, the amplitude of one or more pulses of the transmitted pulse sequence 112 may vary due to reflections on moving object 106 and stationary object 118, thereby causing variations in the pulse sequence 154 received by receiving antenna 120. As another example, the phase associated with the transmitted pulse sequence 112 may vary due to reflections and Doppler effects on moving object 106, thereby causing variations in the pulse sequence 154 received by receiving antenna 120.

[0044] Transmitter 102 can transmit one or more pulses 112 via channel 108 through transmission antenna 142. In examples, each pulse can be an electromagnetic wave with an amplitude that increases and then decreases, or an electromagnetic wave with an amplitude that decreases and then increases, and the pulse sequence is such an electromagnetic wave burst. Transmitter 102 can transmit two sequences 112 as shown, but can transmit more or fewer sequences, where each sequence is the same or different. The transmitted pulse sequence 112 can be arranged into frames 114 of pulses, and in examples, transmitter 102 can transmit multiple frames 114 separated by time interval 116, where each frame 114 includes a corresponding pulse sequence 112. In some examples, the time interval 116 between frames 114 can be fixed, for example, 1 millisecond, or the time interval 116 between frames 114 can be varied. Furthermore, in some examples, the Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 standard can specify an example format for frame 114. Frame 114 can have a format with one or more fields, such as a preamble and a data payload. The preamble may include one or more symbols, where each symbol may be identical and is defined by one or more ternary codes. In the example, the preamble of frame 114 may have up to 512 symbols, and the pulse sequence 112 may represent one or more symbols in the preamble of frame 114.

[0045] In this example, transmitter 102 may be arranged to transmit a sequence 112 of one or more pulses by modulation on a carrier wave to form radio frequency (RF) pulses. The RF pulses may be synthesized from two amplitude-modulated sinusoidal carriers with phase offsets, referred to as in-phase and quadrature components, or from an amplitude-modulated sinusoidal carrier with in-phase components. In some examples, the pulses may have a bandwidth of 500 MHz and be transmitted at carrier frequencies in the range of 3.1 GHz to 10.6 GHz, as associated with ultra-wideband (UWB) radar systems.

[0046] The receiving antenna 120 and the analog / digital front end 104 can receive a pulse sequence 154. The pulse sequence 154 is exemplary in nature, and the sequence may depend on the characteristics of the moving object 106 and the stationary object 118. Furthermore, in examples, a pulse sequence such as pulse sequence 154 may define a frame. For example, the receiving antenna 120 may be arranged as a chip receiving antenna on a printed circuit board (PCB). In some examples, the analog / digital front end 104 may be a component of a real receiver to demodulate the pulse sequence 154 when the pulse sequence 112 is in-phase modulated on a carrier. In some examples, the analog / digital front end 104 may be a component of a complex receiver to demodulate the pulse sequence 154 when the pulse sequence 112 is in-phase (I) and quadrature (Q) modulated on a carrier. The analog / digital front end 104 may include one or more signal processing components, such as a low-noise amplifier, mixer, local oscillator, filter, and analog-to-digital converter, to facilitate this demodulation.

[0047] The analog / digital front end 104 can provide the received pulse sequence to the channel impulse response detector 122. In this example, the received pulse sequence can be defined by the digital signal of the data samples. The channel impulse response detector 122 can determine the CIR of channel 108 based on the CIR estimator 124 and the CIR preprocessor 126. The CIR estimator 124 can determine the CIR. The input to the CIR estimator can be the received pulse sequence and the expected pulse sequence. In this example, the expected pulse sequence can indicate the transmitted pulse sequence 112, such as the symbols in the preamble of frame 114 transmitted by transmitter 102. During the configuration of the channel impulse response detector 122, the expected pulse sequence can be stored in a memory (not shown) associated with the CIR estimator 128, and the expected pulse sequence is updated if the transmitted pulse sequence 112 changes. The CIR estimator 124 can perform cross-correlation between the received pulse sequence and the expected pulse sequence to estimate the CIR. In some examples, cross-correlation can be a function of the displacement of the received pulse sequence relative to the expected pulse sequence, as well as a measure of the similarity of one pulse sequence to another.

[0048] The estimated CIR can be defined by a complex number having a real part and an imaginary part in a Cartesian coordinate system. In this example, the estimated CIR can then be input to a CIR preprocessor 126 that preprocesses the CIR. Preprocessing by the CIR preprocessor 126 can include applying one or more filters, such as a moving average filter or a low-pass filter, to the CIR. A moving average filter operates by averaging multiple points from the input signal to produce each point in the output signal. The points from the input signal can be the real components of the CIR, and the output signal can have reduced high-frequency noise. Alternatively, the points from the input signal can be the imaginary components of the CIR, and the output signal can have reduced high-frequency noise. A low-pass filter can be a frequency response applied to the CIR that reduces high-frequency noise in the CIR. Similarly, a low-pass filter can be applied to either the real or imaginary components of the CIR. The CIR processed by the CIR preprocessor 126 can be output to a phase processing system 128.

[0049] Phase processing system 128 may be arranged with phase signal extractor 130 and object detector 132. Phase processing system 128 may receive CIR from CIR detector 122 and detect moving object 106 between transmitter 102 and analog / digital front end 104. Phase extractor 130 may determine the phase value of CIR phase over time by converting one or more complex numbers of CIR to corresponding phase values ​​associated with a polar coordinate system. The amplitude of the phase value may indicate the speed of the moving object, with higher amplitude indicating higher speed and lower amplitude indicating lower speed. In this example, phase extractor 130 may perform the conversion using a coordinate rotation digital computer (CORDIC) that converts the complex numbers of CIR from Cartesian coordinates to polar coordinates. Phase extractor 130 may store the CIR phases of CIR in memory 134 of phase processing system 128 as CIR phases 1…N. In this example, memory 134 shows three CIR phases 1, 2, and 3 stored in memory 134, but more or fewer CIR phases may be stored. Phase extractor 130 can determine phase signal 140 based on phase values ​​associated with one or more CIR phases stored in memory 134. Phase signal 140 can be a time-varying signal characterizing how the phase value of the CIR phase of the corresponding CIR changes over time. In some examples, phase signal 140 can be processed by a filter, such as a low-pass filter, to reduce noise associated with the phase signal. The low-pass filter can have the same frequency response as the low-pass filter used by CIR preprocessor 126, or a different frequency response.

[0050] Phase signal 140 can be provided to object detector 132, which determines whether phase signal 140 indicates the presence or absence of a moving object in channel 108. Object detector 132 may have comparator 136 to compare phase signal 140 with target signal 138. Target signal 138 may be a time-varying signal of phase value resulting from the movement of a specific object in channel 108. In this example, target signal 138 may be stored in the memory (not shown) of phase processing system 128 during configuration and / or updated based on a specific moving object to be detected. Object detector 132 can access this target signal and provide it to comparator 136. Comparator 136 can compare target signal 138 with phase signal 140. Based on the comparison of phase signal 140 and target signal 138, which in this example defines a corresponding set of data points, it is determined whether a specific moving object has been detected. If phase signal 140 and target signal 138 are “similar” to those described further in detail below, it is determined that a moving object has been detected. If the comparison between phase signal 140 and target signal 138 is not "similar" to the description further described below, it is determined that no moving object has been detected. Object detector 132 may output an indication of this detection.

[0051] In this example, the phase signal comprises time-varying phase values, and the target signal comprises time-varying phase values; these phase values ​​are compared to detect a moving object. In this respect, the phase signal and the target signal are in the time domain. Furthermore, the phase signal is determined based on the CIR, which is not converted to the frequency domain, such as a Fast Fourier Transform (FFT). Because no frequency domain transformation is performed to detect the moving object, detection requires low power consumption and low memory requirements. Detecting the moving object by converting the CIR to the frequency domain (e.g., a complex number varying according to frequency) and analyzing it increases power and / or memory requirements.

[0052] In this example, the moving object detector 100 may be a subsystem of a larger system. In one application, the moving object detector 100 may be located on a vehicle 144 to sense moving objects relative to the vehicle 144. For example, the moving object detector 100 may be positioned on the rear bumper 146 of the vehicle 144 to facilitate the sensing of a kick below the rear bumper 146. A kick could indicate that a person wants to open the trunk of the vehicle 144 and that the moving object to be detected is a leg. Alternatively, the moving object detector 100 may be located inside the interior 148 of the vehicle 144 to facilitate the detection of vital signs of a passenger in the vehicle 144, such as their respiratory rate and heart rate. In another application, the moving object detector 100 may be located on a computing device such as an Internet of Things (IoT) device 152, such as the illustrated light or safety device, to facilitate the detection of movement that turns on a light or activates an alarm, respectively.

[0053] In this example, one or more of the transmitter 102, analog / digital front-end 104, channel impulse response detector 122, and phase processing system 128 may be implemented on the same integrated circuit (IC) or separate corresponding ICs. If the components are implemented on the same IC (e.g., to form a transceiver), the transmitter 102 and analog / digital front-end 104 may also be synchronized in phase to facilitate the transmission and reception of the pulse sequence 112. Synchronization may be provided by a local oscillator shared by the transmitter 102 and analog / digital front-end 104 on the IC. If the transmitter 102 and analog / digital front-end 104 are on separate corresponding ICs, the transmitter 102 and analog / digital front-end 104 may also be synchronized in phase to facilitate the transmission and reception of the pulse sequence 112. In this example, the transmitter 102 and analog / digital front-end 104 may share an oscillator or have separate oscillators with further synchronization. Furthermore, in some examples, one or more circuitry systems associated with transmitter 102, analog / digital front-end 104, channel impulse response detector 122, and phase processing system 128 may be separated by networks such as a Local Interconnect Network (LIN) or Controller Area Network (CAN). For example, the CIR output by the CIR estimator 124 circuitry system can be transmitted via network to an electronic control unit (ECU) having circuitry associated with the channel impulse response detector 122 and phase processing system 128 to detect moving object 106.

[0054] In this example, instead of using separate antennas shown as transmit antenna 142 and receive antenna 120 to transmit and receive the pulse sequence 112, transmitter 102 and analog / digital front-end 104 may share a common antenna. Transmitter 102 and analog / digital front-end 104 may be coupled to this shared antenna, and time multiplexing of transmission and reception may be performed through this shared antenna. Furthermore, in some examples, one of antennas 120 or antenna 142 may include two or more antennas.

[0055] Figure 2 The generation of the phase signal in the moving object detector 100 is illustrated in more detail. The transmitter 102 can transmit multiple frames 114, which causes the analog / digital front end 104 to receive multiple frames 252-256 (which are similar to pulse sequences 154) via the receiving antenna 120 based on the transmitted multiple frames 114. Each of the multiple frames 252-256 can be associated with a corresponding pulse sequence, such as one of the pulse sequences 202-206. Furthermore, in some examples, each frame can be separated by a fixed time interval 208, which can be 1 millisecond. In other examples, the time interval 208 can be variable.

[0056] CIR estimator 124 knows that the transmitted pulse sequence 112 may be a expected pulse sequence. CIR estimator 124 may correlate the expected pulse sequence with the received pulse sequences from frames 252-256 of antenna 120 to determine the corresponding CIR of channel 108 between transmitter 102 and receiving antenna 120. For example, CIR estimator 124 may correlate the received pulse sequence 202 with the expected pulse sequence to determine the CIR. In some examples, the received pulse sequence 202 may include one or more repeating pulse subsequences, each pulse subsequence possibly corresponding to the same symbol. The repeating subsequences may be averaged together to remove noise, and the averaged subsequences may be correlated with the expected pulse sequence to determine the CIR associated with the frame. In this example, the CIR may be determined for frame 252 with pulse sequence 202, for frame 254 with pulse sequence 204, and for frame 256 with pulse sequence 206.

[0057] The CIR can be represented by multiple complex numbers, and the phase extractor 130 can determine a phase value for each complex number, which can be in the range of -180 degrees to 180 degrees or in some other range in this example. The aggregation of phase values ​​defines the CIR phase. Example CIR phases are shown as CIR phases 246, 248, and 250, respectively, corresponding to frames 252, 254, and 256. This process can be repeated when additional frames including the corresponding pulse sequences are received.

[0058] Each complex number forming a CIR phase can have a time index. The time index can define a time position within the CIR. The phase value associated with the complex number can have an associated time index. The time index can define a time position within the CIR phase. In this respect, CIR phase 246 can be a graph of phase values ​​210 (i.e., the amplitude of the phase) with time-dependent time indices along the time axis. In this example, the time index can also be referred to as a tap number, which uniquely identifies each phase value of phase value 210. For example, a first phase value can be labeled as tap 1, a second phase value as tap 2, a third phase value as tap 3, and so on, where N = 3 tap values. The same tap number for phase values ​​in multiple CIR phases 246-250 indicates that the complex numbers used to generate the phase values ​​have the same time index in the corresponding CIR. For example, tap 2 in CIR phases 246, 248, and 250 can correspond to a complex number in the corresponding CIR with time index 2.

[0059] In this example, phase values ​​can be selected across multiple CIR phases with the same number of taps. For illustration, tap 1 associated with each of CIR phases 246-250 can be selected as shown by phase values ​​224-228. Phase values ​​216-220 can be aggregated to form a candidate phase signal 230. In some examples, the phase extractor 130 can interpolate phase values ​​to define the candidate phase signal 230. This process can be repeated for tap 2 selected for each CIR phase, as shown by phase values ​​216-220. Phase values ​​216-220 can be aggregated to form a candidate phase signal 222. This process can continue for other taps, such as tap 3 selected for each CIR phase, tap 4 selected for each CIR phase, and so on. The phase extractor 130 can then select one of the candidate phase signals as a phase signal output and compare that phase signal with the target signal to detect a moving object. In some examples, the selection can be based on the amplitude of one or more of the candidate phase signals. For example, the selected phase signal may be one of the candidate phase signals that has the highest amplitude compared to other candidate phase signals. As another example, the selected phase signal may be one of the candidate phase signals that has the highest power. As yet another example, the selected phase signal may have the maximum amplitude or power exceeding a threshold level. In addition to amplitude and / or power, or in place of amplitude and / or power, selection may also be based on other criteria.

[0060] The comparison of the phase signal and the target signal may include a value indicating the correlation between the phase signal and the target signal. The comparison may involve calculating a normalized absolute error between the phase signal and the target signal. If the normalized absolute error is less than a threshold amount, the phase signal matches the target signal. If the normalized absolute error is not less than the threshold amount, the phase signal does not match the target signal. Alternatively, the comparison of the phase signal and the target signal may include applying a matched filter associated with the target signal to the phase signal process. Matched filtering is a process used to detect a known signal (i.e., the target signal) embedded in noise. The matched filter applied to the phase signal can indicate the degree of matching between the target signal and the phase signal. If the degree of matching exceeds a threshold amount, a moving object is detected. If the degree of matching does not exceed the threshold amount, no moving object is detected. The comparison between the phase signal and the target signal may also be performed in other ways.

[0061] In this example, the moving object detector 100 may take the form of a UWB radar sensor operating in the 6.5 GHz band. Additionally, in some examples, the moving object detector 100 may be mounted on the rear bumper 146 of the vehicle 144. In this example, the transmitter 102 transmits multiple pulse sequences. The analog / digital front end 104 may receive multiple pulse sequences based on the transmitted pulse sequences, and the moving object detector 100 may determine whether to open the trunk. For example, the object detector 132 may compare a phase signal determined based on the transmitted and received pulse sequences with a target signal indicating a kick. If the object detector 132 determines a match between the phase signal and the target signal, the trunk is opened. If the object detector 132 does not determine a match between the phase signal and the target signal, the trunk is not opened.

[0062] Figures 3A-3C An example phase signal is shown, determined by multiple accelerated kicks performed by a person against a moving object detector 100 mounted on the rear bumper of a vehicle. The example phase signal can be compared with a target signal to determine whether a kick was detected.

[0063] Figure 3A Multiple example phase signals 300, determined by detector 100, are shown, generated by an accelerated kick toward the rear bumper of a vehicle. The phase signals 300 are plotted as a function of phase values ​​along axis 302 and time along axis 304. The CIR can be determined for each received pulse sequence associated with a corresponding transmitted pulse sequence. Phase signals can be determined using, for example, a phase value such as tap N in each CIR phase of each CIR. For example, tap 17, as shown in CIR 17, can define a phase signal associated with each kick shown as kicks 1-6, and a phase signal 306 for kick 4. Phase signals for taps 6, 8, 14, and 16, identified by CIR 6, CIR 8, CIR 14, and CIR 16, are also shown. The phase signal for each kick has a peak shape, and the amplitude of the peak phase increases with the time and velocity of the kick.

[0064] Figure 3BAn example of a magnified view of the phase signal 308 for one of the kicks is shown. The phase signal 308 is plotted as a function of the phase value along axis 302 and time along axis 304. The phase signal 308 has a phase slope that increases as the leg associated with the kick moves toward the moving object detector 100 and a phase slope that decreases as the leg moves away from the moving object detector 100. The increased phase slope is due to the increased Doppler shift, which causes an increased phase shift in the carrier frequency of the received pulse and indicates a higher velocity. Similarly, the decreased phase slope is due to the decreased Doppler shift in the carrier frequency of the received pulse, which causes a decreased phase shift and indicates a lower velocity. In this example, the phase signal 310 associated with CIR 17 may have a maximum phase, indicated by a phase value of 48 degrees and selected by the phase extractor 130.

[0065] Figure 3C An example comparison is shown between a target signal 312 indicating a kick and a phase signal 314 output by the phase extractor 130. In this example, the target signal 312 may define the time-varying phase value of the kick indication. The target signal 312 and the phase signal 314 are plotted as a function of the phase value along axis 302 and time along axis 304. The phase signal 314 can be compared with the target signal 312 by the object detector 132 to determine whether a moving object associated with the target signal is detected. If the comparison indication exceeds a threshold amount, a moving object associated with the target signal is detected. If the comparison indication does not exceed the threshold amount, no moving object associated with the target signal is detected.

[0066] Figures 4A-4B The illustration demonstrates the detection of vital signs, such as a person's heart rate or respiratory rate, based on the phase signal output by phase extractor 130. The human may be in a vehicle, where transmitter 102 can transmit multiple frames, each with a pulse sequence, and analog / digital front-end 104 in the vehicle can receive multiple frames, each with a pulse sequence based on the transmitted frames. The human may be sitting quietly and breathing according to an example pattern: 5x normal -> 5x rapid -> breath-holding -> 5x normal breathing. Phase extractor 130 can determine the phase signal based on the transmitted and received frames.

[0067] Figure 4A A phase signal 400 associated with taps of the CIR phases of multiple CIRs is shown. Phase signal 400 indicates a moving object in the vehicle. In this example, periodic phase peaks 1-5 correspond to a moving object in the form of a passenger's breathing or breathing pattern in the vehicle.

[0068] Figure 4B Shown in Figure 4AThe "breath-holding" portion 402 is a zoom of the phase signal 400. Peaks 1-7 during the "breath-holding" portion 402 indicate a moving object in the form of a heartbeat, which beats at approximately 7 times per 4 seconds or 105 bpm.

[0069] In this respect, detector 100 has the resolution to detect vital signs of passengers in a vehicle, such as respiratory rate and even heart rate, without having to perform an FFT by matching the phase signal 400 with a target signal that varies with two phase values ​​over time. This allows for moving object detection with lower power consumption and memory requirements compared to the frequency domain.

[0070] Example Operation

[0071] Figure 5 This is an example flowchart of a function 500 associated with detecting a moving object by detector 100. In this example, the function in function 500 can be implemented using circuit systems such as analog circuit systems, mixed-signal circuit systems, memory circuit systems, logic circuit systems, and / or processing circuit systems, which execute code stored in memory, and when executed by the processing circuit system, this code performs the disclosed function.

[0072] At 502, transmitter 102 transmits multiple frames. Each frame includes a pulse sequence modulated on a carrier having a carrier frequency. Transmitter 102 transmits the pulse sequence through channel 108.

[0073] At 504, the analog / digital front end 104 receives multiple frames based on the transmitted multiple frames. Each received frame may include a pulse sequence received based on a corresponding transmitted pulse sequence. In this example, the transmitted pulse sequence may be received directly by the receiving antenna 120 as a received pulse sequence, or as a result of reflections in the path between the transmitter 102 and the receiving antenna 120 on the static object 118 and / or the moving object 106 in channel 108.

[0074] At 506, the CIR is determined for each received pulse sequence. The CIR estimator 124 can determine the CIR. The CIR can be based on the correlation between the received pulse sequence and the corresponding expected pulse sequence. In some examples, the CIR preprocessor 126 can preprocess the CIR using filters such as a low-pass filter or a running average filter to remove noise from the CIR.

[0075] At 508, the phase value of the tap of the CIR phase associated with the CIR is determined to define the phase signal. The phase signal can be determined by phase extractor 130. In some examples, phase extractor 130 can determine multiple candidate phase signals, each associated with a different tap of the CIR phase associated with the CIR, and the phase signal with the maximum amplitude or maximum power can be the phase signal output by phase extractor 130. The phase value of the phase signal can indicate the speed at which a moving object moves over time. In some examples, the phase signal can be further preprocessed using a filter, such as a low-pass filter, to remove noise from the phase signal.

[0076] At 510, the phase signal is compared with the target signal. As an example, the target signal could be a predetermined signal indicating a type of movement such as kicking, respiratory rate, or heart rate. The comparison performed by the object detector 132 can indicate the correlation between the phase signal and the target signal. In this example, the comparison can be based on a matched filter or normalized absolute error calculation.

[0077] If the comparison indicates a correlation exceeding a threshold, then at point 512, a moving object associated with the target signal is detected. For example, the comparison could indicate the detection of a kick, heart rate, or respiratory pattern. If the comparison indicates a correlation not exceeding the threshold, then at point 514, no moving object associated with the target signal is detected.

[0078] In 516, the characteristics of the output phase signal are described. These characteristics could be the amplitude of the phase signal indicating the speed of a moving object, or the frequency of peaks in multiple phase signals indicating a person's respiratory rate or heart rate. These characteristics can be used to perform additional actions. For example, if a kick at a certain speed is detected, the trunk of a vehicle can be opened. As another example, if a respiratory rate or heart rate is detected and the vehicle is locked, the doors can be unlocked to allow passengers to exit the vehicle. Other variations are also possible.

[0079] Figure 6This is an example block diagram of a computer device 600, such as a moving object detector 100, that performs functions associated with identifying moving objects. The computer device 600 may have a processing circuitry 602 (which may include multiple processors, multiple cores, multiple nodes, and / or implement multithreading, etc.) and a memory 604, such as system memory (e.g., one or more of cache, SRAM, DRAM, zero-capacitance RAM, dual-transistor RAM, eDRAM, EDO RAM, DDR RAM, EEPROM, NRAM, RRAM, SONOS, PRAM, etc.), or any one or more other possible implementations of non-transitory machine-readable media. The memory 604 may store computer code, program instructions, or program code for performing one or more operations or control operations associated with the channel impulse response detector 122 or the phase processing system 128 via corresponding software modules 610-612. The computer device 600 also includes a bus 616 (e.g., PCI, ISA, PCI-Express) coupling the processing circuitry 602, the memory 604, and the interface 606. In some examples, interface 606 may include transmitter 102 and analog / digital front end 104, which receives pulses to be transmitted from bus 616 and transmits pulses to be transmitted through bus 616.

[0080] In one embodiment, a method for detecting a moving object is disclosed. The method includes: receiving a plurality of frames transmitted through a channel via a moving object detector; determining one or more channel impulse responses (CIRs) associated with the channel based on the received plurality of frames; determining a CIR phase of each of the CIRs; forming a phase signal based on the phase values ​​of the CIR phases of each of the CIRs; comparing the phase signal with the target signal; and detecting a moving object in the channel based on the comparison. In this embodiment, the phase values ​​of the CIR phases defining the phase signal are located at the same time position in each of the CIR phases. In this embodiment, the CIR phases and the phase signal define phase values ​​that vary over time. In this embodiment, the method of forming the phase signal includes: forming a first candidate phase signal and a second candidate phase signal, wherein the first candidate phase signal is associated with a phase value located only at a first time position in each of the CIR phases, and the second candidate phase signal is associated with a phase value located only at a second time position in each of the CIR phases; and selecting the first candidate phase signal or the second candidate phase signal as the phase signal based on a corresponding amplitude or power associated with the first candidate phase signal or the second candidate phase signal exceeding a threshold level. In one embodiment, the target signal defines a time-varying phase value indicating a kick toward a vehicle, and the detection of a moving object includes detecting a kick toward a vehicle. In another embodiment, the target signal defines a time-varying phase value indicating human vital signs, and the detection of a moving object includes detecting human vital signs. In another embodiment, the target signal includes a time-varying phase value characterizing a moving object. In another embodiment, a method for detecting a moving object in a channel includes determining that the correlation between the target signal and the phase signal exceeds a threshold level. In another embodiment, a method for detecting a moving object in a channel includes providing the velocity of the moving object based on the amplitude of the phase signal. In another embodiment, a method for determining one or more CIRs by a detector includes correlating one or more pulses of a pulse sequence of received frames with one or more expected pulses, the method further including transmitting multiple frames through the channel, wherein the IEEE 802.15.4 standard defines the format and content of the multiple transmitted frames.

[0081] In another embodiment, a moving object detector is disclosed. The moving object detector includes: an analog / digital front end implemented with circuitry to receive multiple frames from a channel; a CIR estimator implemented with circuitry to determine one or more CIRs of the channel based on the received multiple frames; a phase extractor implemented with circuitry to determine the CIR phase of each CIR and form a phase signal based on the phase value of the CIR phase of each of the CIRs; and an object detector implemented with circuitry to compare the phase signal with a target signal and detect a moving object in the channel based on the comparison. In this embodiment, the phase value of the CIR phase of each of the CIRs defining the phase signal is located at the same time position in each of the CIR phases. In this embodiment, the CIR phases and the phase signal have phase values ​​that vary over time. In one embodiment, a phase extractor for forming a phase signal includes: circuitry for forming a first candidate phase signal and a second candidate phase signal, wherein the first candidate phase signal is associated with a phase value located only at a first time position in each of the CIR phases, and the second candidate phase signal is associated with a phase value located only at a second time position in each of the CIR phases; and circuitry for selecting the first candidate phase signal or the second candidate phase signal as a phase signal based on a corresponding amplitude or power associated with the first candidate phase signal or the second candidate phase signal exceeding a threshold level. In another embodiment, a target signal defines a time-varying phase value associated with a kick toward a vehicle, and wherein an object detector for detecting a moving object includes circuitry for detecting a kick toward a vehicle. In another embodiment, a target signal defines a time-varying phase value associated with human vital signs, and wherein an object detector for detecting a moving object includes circuitry for detecting human vital signs. In another embodiment, a target signal includes a time-varying phase value characterizing a moving object. In another embodiment, an object detector for detecting a moving object in a channel includes circuitry for determining that the correlation between the target signal and the phase signal exceeds a threshold level. In one embodiment, the object detector for detecting a moving object in the channel includes a circuit system for providing the speed of the moving object based on a phase signal. In another embodiment, the detector further includes a transmitter implemented with the circuit system to transmit multiple frames over the channel, wherein the format and content of the multiple transmitted frames are defined by the Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 standard.

[0082] Some embodiments have been described in detail above, and various modifications are also possible. The disclosed subject matter, including the functional operations described herein, can be implemented in electronic circuit systems, computer hardware, firmware, software, or combinations thereof, such as in the structural devices and their structural equivalents disclosed herein: potentially including programs (e.g., program code encoded in a non-transitory computer-readable medium, which may be a memory device, storage device, machine-readable storage substrate, or other physical, machine-readable medium, or a combination thereof) operable to cause one or more data processing devices, such as a processor, to perform the described operations.

[0083] Although this specification contains numerous details, these details should not be construed as limiting the scope of what may be claimed, but rather as descriptions of features specific to particular embodiments. Certain features described in this specification in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments. Furthermore, although features may be described above as functioning in certain combinations and even initially claimed in this manner, in some cases, one or more features from the claimed combination may be removed from the combination, and the claimed combination may involve sub-combinations or variations thereof.

[0084] Similarly, although operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring such operations to be performed in the specific order shown or in a sequential manner, or to perform all of the shown operations to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Furthermore, the separation of the various system components in the embodiments described above should not be construed as requiring such separation in all embodiments.

[0085] The phrase “at least one of” preceding a list with the conjunction “and” should not be considered an exclusive list, nor should it be interpreted as a list of categories with one item from each category, unless the exact statement is otherwise. A sentence stating “at least one of A, B, and C” may contain only one of the listed items, an integer multiple of the listed items, one or more of the listed items, and another unlisted item.

[0086] Other embodiments are within the scope of the appended claims.

Claims

1. A method for detecting moving objects, characterized in that, The method includes: Multiple frames transmitted through the channel are received using a moving object detector; The detector determines one or more channel impulse responses (CIRs) associated with the channel based on multiple received frames. The CIR phase of each of the CIRs is determined by the detector; The detector forms a phase signal based on the phase value of the CIR phase of each of the CIRs, wherein the phase value of the CIR phase of each of the CIRs is located at the same time position of each of the CIR phases; and the phase extractor forms the phase signal by inserting the phase value of the CIR phase located at the same time position of each of the CIR phases. The phase signal is compared with the target signal using the detector; and The detector detects the moving object in the channel based on the comparison.

2. The method according to claim 1, characterized in that, The CIR phase and the phase signal define a phase value that varies with time.

3. The method according to claim 1, characterized in that, Forming the phase signal includes: forming a first candidate phase signal and a second candidate phase signal, wherein the first candidate phase signal is associated with a phase value located only at a first time position in each of the CIR phases, and the second candidate phase signal is associated with a phase value located only at a second time position in each of the CIR phases; and selecting the first candidate phase signal or the second candidate phase signal as the phase signal based on a corresponding amplitude or power associated with the first candidate phase signal or the second candidate phase signal exceeding a threshold level.

4. The method according to claim 1, characterized in that, The target signal defines a phase value that varies over time, the phase value indicating a kick toward the vehicle, and wherein detecting the moving object includes detecting the kick toward the vehicle.

5. The method according to claim 1, characterized in that, The target signal defines a phase value that varies over time, the phase value indicating human vital signs, and wherein detecting the moving object includes detecting the human's vital signs.

6. The method according to claim 1, characterized in that, The target signal includes a phase value that varies over time, and the phase value characterizes the moving object.

7. The method according to claim 1, characterized in that, Detecting the moving object in the channel includes determining that the correlation between the target signal and the phase signal exceeds a threshold level.

8. The method according to claim 1, characterized in that, Detecting the moving object in the channel includes providing the speed of the moving object based on the amplitude of the phase signal.

9. A moving object detector, characterized in that, include: Analog / digital front end, which is implemented using circuitry to receive multiple frames from a channel; A CIR estimator, implemented with a circuit system, determines one or more CIRs of the channel based on multiple received frames; A phase extractor, implemented with a circuit system, determines the CIR phase of each of the CIRs and forms a phase signal based on the phase value of the CIR phase of each of the CIRs, wherein the phase value of the CIR phase of each of the CIRs is located at the same time position of each of the CIR phases; Furthermore, the phase extractor forms the phase signal by inserting the phase value of the CIR phase located at the same time position in each of the CIR phases; as well as An object detector is implemented using a circuit system to compare the phase signal with a target signal and detect the moving object in the channel based on the comparison.

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