Patent ID: 12241968

DETAILED DESCRIPTION OF EMBODIMENTS

The following describes the technical solutions in this application with reference to the accompanying drawings.

Embodiments of this application provide a radar ranging method and device, a radar, and an in-vehicle system, and mainly provide a solution for determining a timing point for a saturated echo signal. This can improve precision of determining time of flight, thereby reducing a distance error of radar ranging.

For ease of understanding the technical solutions of the embodiments of this application, several terms designed in this application are first described.

Saturated echo signal: The saturated echo signal indicates that strength of an echo signal received by a receiver is too high and exceeds a dynamic range of the receiver. Consequently, echo signal clipping is caused, and usually broadening of a falling edge is accompanied with.

Saturated sampling sequence: The saturated sampling sequence refers to a sampling sequence signal obtained after a received saturated echo signal is sampled.

Time of flight: The time of flight refers to a time difference between a transmit moment at which a signal is sent by a radar and a receive moment at which an echo signal is reflected by a target object.

Timing point: The timing point refers to a designated fixed location on a signal waveform transmitted by the radar and an echo signal waveform received by the radar, to determine the time of flight. The time of flight may be obtained by calculating a time difference between two timing points of the transmit signal waveform and the echo signal waveform.

The radar ranging method in the embodiments of this application may be widely used in various fields, such as the field of artificial intelligence, an unmanned driving system, an autonomous driving system, an augmented reality (augmented reality, AR) technology, and a virtual reality (virtual reality, VR) technology. Autonomous driving is a mainstream application in the field of artificial intelligence. An autonomous driving technology relies on collaboration of computer vision, a radar, a monitoring apparatus, a global positioning system, and the like, to enable a motor vehicle to implement autonomous driving without human intervention. For example, the field of autonomous driving may include intelligent vehicles, unmanned vehicles, and the like.

FIG.1is a schematic diagram of a structure of an autonomous vehicle according to an embodiment of this application. A radar in this embodiment of this application may be a radar126inFIG.1, and the radar126may be a laser radar, a laser range finder, or a millimeter-wave radar. Optionally, a function of a processing unit210in a radar200inFIG.2may be implemented by a processor113inFIG.1, or may be implemented by another type of processing chip, such as a field programmable gate array (field programmable gate array, FPGA) or an application-specific integrated circuit (application specific integrated circuit, ASIC).

As shown inFIG.1, in an embodiment, a vehicle100is configured in a fully or partially autonomous driving mode. For example, the vehicle100in the automatic driving mode may control the vehicle100. A manual operation may be performed to determine current statuses of the vehicle and an ambient environment of the vehicle, determine possible behavior of at least one another vehicle in the ambient environment, determine a confidence level corresponding to a possibility that the another vehicle performs the possible behavior, and control the vehicle100based on determined information. When the vehicle100is in the autonomous driving mode, the vehicle100may be set to operate without interacting with a person.

The vehicle100may include various subsystems, for example, a travel system102, a sensor system104, a control system106, one or more peripheral devices108, a power supply110, a computer system112, and a user interface116. Optionally, the vehicle100may include more or fewer subsystems, and each subsystem may include a plurality of elements. In addition, each subsystem and element of the vehicle100may be interconnected in a wired or wireless manner.

The travel system102may include a component providing power motion to the vehicle100. In an embodiment, the travel system102may include an engine118, an energy source119, a transmission apparatus120, and wheels/tires121. The engine118may be a combination of an internal combustion engine, an electric motor, an air compression engine, or another type of engine, for example, a hybrid engine including a gasoline engine and an electric motor, or a hybrid engine including an internal combustion engine and an air compression engine. The engine118converts the energy source119into mechanical energy.

Examples of the energy source119include gasoline, diesel, another petroleum-based fuel, propane, another compressed gas-based fuel, ethanol, a solar panel, a battery, and another power source. The energy source119may also provide energy to another system of the vehicle100.

The transmission apparatus120may transmit mechanical power from the engine118to the wheel121. The transmission apparatus120may include a gearbox, a differential, and a drive shaft. In an embodiment, the transmission apparatus120may further include another component, for example, a clutch. The drive shaft may include one or more shafts that may be coupled to one or more wheels121.

The sensor system104may include several sensors that sense information about the ambient environment of the vehicle100. For example, the sensor system104may include a positioning system122(where the positioning system may be a global positioning system (global positioning system, GPS), a BeiDou system or another positioning system), an inertial measurement unit (inertial measurement unit, IMU)124, the radar126, and a camera130. The sensor system104may further include a sensor (for example, an in-vehicle air quality monitor, a fuel gauge, or an engine oil thermometer) of an internal system of the monitored vehicle100. One or more pieces of sensor data from these sensors can be used to detect an object and a corresponding feature (a location, a shape, a direction, a speed, or the like) of the object. Such detection and recognition are key functions of a safe operation of the autonomous vehicle100.

The positioning system122may be configured to estimate a geographic location of the vehicle100. The IMU124is configured to sense location and orientation changes of the vehicle100based on an inertial acceleration. In an embodiment, the IMU124may be a combination of an accelerometer and a gyroscope.

The radar126may sense an object in an ambient environment of the vehicle100by using a radio signal, an optical signal, or a laser signal. In some embodiments, in addition to sensing the object, the radar126may further be configured to sense a speed and/or an advancing direction of the object. In some embodiments, if the radar126is a laser range finder, the radar126may include one or more laser sources, a laser scanner, one or more detectors, and another system component.

The camera130may be configured to capture a plurality of images of the ambient environment of the vehicle100. The camera130may be a static camera or a video camera.

The control system106controls operations of the vehicle100and components of the vehicle100. The control system106may include various elements, including a steering system132, a throttle134, a braking unit136, a sensor fusion algorithm138, a computer vision system140, a route control system142, and an obstacle avoidance system144.

The steering system132is operable to adjust an advancing direction of the vehicle100. For example, in an embodiment, the steering system132may be a steering wheel system.

The throttle134is configured to: control an operating speed of the engine118and further control a speed of the vehicle100.

The braking unit136is configured to control the vehicle100to decelerate. The braking unit136may use friction to slow down the wheel121. In another embodiment, the braking unit136may convert kinetic energy of the wheel121into an electric current. Alternatively, the braking unit136may reduce a rotational speed of the wheel121in another form to control the speed of the vehicle100.

The computer vision system140is operable to process and analyze the image captured by the camera130, to recognize the object and/or a feature in the ambient environment of the vehicle100. The object and/or the feature may include a traffic signal, a road boundary, and an obstacle. The computer vision system140may use an object recognition algorithm, a structure from motion (structure from motion, SFM) algorithm, video tracking, and another computer vision technology. In some embodiments, the computer vision system140may be configured to draw a map for an environment, track an object, estimate a speed of an object, and the like.

The route control system142is configured to determine a running route of the vehicle100. In some embodiments, the route control system142may determine the running route of the vehicle100with reference to data from the sensor fusion algorithm138, the GPS122, and one or more predetermined maps.

The obstacle avoidance system144is configured to recognize, evaluate, and avoid or bypass, in another manner, a potential obstacle in an environment of the vehicle100.

Certainly, in an example, the control system106may additionally or alternatively include a component other than those shown and described. Alternatively, some of the components shown above may be reduced.

The vehicle100interacts with an external sensor, another vehicle, another computer system, or a user by using the peripheral device108. The peripheral device108may include a wireless communications system146, a vehicle-mounted computer148, a microphone150, and/or a speaker152.

In some embodiments, the peripheral device108provides a means for a user of the vehicle100to interact with the user interface116. For example, the vehicle-mounted computer148may provide information to the user of the vehicle100. The user interface116may further receive a user input by operating the vehicle-mounted computer148. The vehicle-mounted computer148may be operated by using a touchscreen. In another case, the peripheral device108may provide a means for the vehicle100to communicate with another device located in the vehicle. For example, the microphone150may receive audio (for example, a voice command or another audio input) from the user of the vehicle100. Similarly, the speaker152may output audio to the user of the vehicle100.

The wireless communications system146may perform wireless communication with one or more devices directly or through a communications network. For example, the wireless communications system146may use 4G cellular communication, such as a long term evolution (long term evolution, LTE) system, an LTE frequency division duplex (frequency division duplex, FDD) system, a universal mobile telecommunications system (universal mobile telecommunication system, UMTS) system, and a worldwide interoperability for microwave access (worldwide interoperability for microwave access, WiMAX) communications system. Alternatively, the wireless communications system146may use 5G cellular communication, such as a future 5th generation (5th generation, 5G) system or a new radio (new radio, NR) system. The wireless communications system146may communicate with a wireless local area network (wireless local area network, WLAN) by using Wi-Fi. In some embodiments, the wireless communications system146may communicate directly with a device through an infrared link or by using Bluetooth or ZigBee (ZigBee). Other wireless protocols, for example, various vehicle communications systems, such as the wireless communications system146, may include one or more dedicated short range communications (DSRC) devices, and these devices may include public and/or private data communication between the vehicle and/or roadside stations.

The power supply110may provide power to various components of the vehicle100. In an embodiment, the power supply110may be a rechargeable lithium-ion or lead-acid battery. One or more battery packs of the battery may be configured to provide power to the various components of the vehicle100. In some embodiments, the power supply110and the energy source119may be implemented together, as in some battery electric vehicles.

Some or all of functions of the vehicle100are controlled by the computer system112. The computer system112may include at least one processor113. The processor113executes instructions115stored in a non-transitory computer-readable medium such as a memory114. The computer system112may alternatively be a plurality of computing devices that control an individual component or the subsystem of the vehicle100in a distributed manner.

The processor113may be any conventional processor, for example, a commercially available CPU. Alternatively, the processor may be a dedicated device such as an ASIC or another hardware-based processor. AlthoughFIG.1functionally illustrates the processor, the memory, and another element of a computer system112in a same block, a person of ordinary skill in the art should understand that the processor, the computer, or the memory may actually include a plurality of processors, computers, or memories that may or may not be stored in a same physical housing. For example, the memory may be a hard disk drive, or another storage medium that is located in a housing different from that of the computer system112. Therefore, it is understood that a reference to the processor or the computer includes a reference to a set of processors or computers or memories that may or may not operate in parallel. Different from using a single processor to perform the steps described herein, some components, such as a steering component and a deceleration component, each may have its own processor that performs only calculation related to a component-specific function.

In various aspects described herein, the processor may be located far away from the vehicle and perform wireless communication with the vehicle. In another aspect, some of processes described herein are performed on a processor disposed inside the vehicle, while others are performed by a remote processor. The processes include necessary steps for performing a single operation.

In some embodiments, the memory114may include the instruction115(for example, program logic), and the instructions115may be executed by the processor113to perform various functions of the vehicle100, including the functions described above. The memory114may also include additional instructions, including instructions used to send data to, receive data from, interact with, and/or control one or more of the travel system102, the sensor system104, the control system106, and the peripheral device108.

In addition to the instruction115, the memory114may further store data, such as a road map, route information, and a location, a direction, a speed, and other such vehicle data of the vehicle, and other information. Such information may be used by the vehicle100and the computer system112when the vehicle100operates in an autonomous mode, a semi-autonomous mode, and/or a manual mode.

The user interface116is configured to provide information to or receive information from the user of the vehicle100. Optionally, the user interface116may include one or more input/output devices in a set of peripheral devices108, for example, the wireless communications system146, the vehicle-mounted computer148, the microphone150, and the speaker152.

The computer system112may control the functions of the vehicle100based on inputs received from the various subsystems (for example, the travel system102, the sensor system104, and the control system106) and from the user interface116. For example, the computer system112may use an input from the control system106to control the steering unit132to avoid an obstacle detected by the sensor system104and the obstacle avoidance system144. In some embodiments, the computer system112is operable to provide control over many aspects of the vehicle100and the subsystems of the vehicle100.

Optionally, one or more of the foregoing components may be installed separately from or associated with the vehicle100. For example, the memory114may be partially or completely separated from the vehicle100. The components may be communicatively coupled together in a wired and/or wireless manner.

Optionally, the foregoing components are merely examples. In actual application, components in the foregoing modules may be added or removed based on an actual requirement.FIG.1should not be construed as a limitation on this embodiment of the present invention.

An autonomous vehicle traveling on a road, for example, the vehicle100, may recognize an object in an ambient environment of the autonomous vehicle, to determine to adjust a current speed. The object may be another vehicle, a traffic control device, or another type of object. In some examples, each recognized object may be considered independently, and based on features of each object, such as a current speed of the object, an acceleration of the object, and a spacing between the object and the vehicle, may be used to determine the speed to be adjusted by the automatic driving vehicle.

Optionally, the autonomous vehicle100or a computing device (for example, the computer system112, the computer vision system140, or the memory114inFIG.1) associated with the autonomous vehicle100may predict behavior of the recognized object based on the feature of the recognized object and a status (for example, traffic, rain, or ice on a road) of the ambient environment. Optionally, the recognized objects depend on the behavior of each other. Therefore, the behavior of a single recognized object may alternatively be predicted by considering all the recognized objects together. The vehicle100can adjust the speed of the vehicle100based on the predicted behavior of the recognized object. In other words, the autonomous vehicle can determine, based on the predicted behavior of the article, a stable state to which the vehicle needs to be adjusted (for example, speeding up, deceleration, or stop). In this process, another factor, for example, a transverse location of the vehicle100on a road on which the vehicle100runs, a curvature of the road, or proximity between static and dynamic objects may also be considered, to determine the speed of the vehicle100.

The vehicle100may be a car, a truck, a motorcycle, a bus, a boat, an airplane, a helicopter, a lawn mower, a recreational vehicle, a playground vehicle, a construction device, a trolley, a golf cart, a train, a handcart, or the like. This is not specifically limited in this embodiment of the present invention.

FIG.2is a schematic diagram of a structure of the radar200. The radar in this embodiment of this application may include a laser radar, a laser range finder, a millimeter-wave radar, or another type of radar. As shown inFIG.2, the radar200includes a transmitter220, a receiver230, and a processing unit210. Optionally, the processing unit210may include a central processing unit (central processor unit, CPU), an FPGA, or an ASIC, or may be another type of processing chip. In a ranging process, the transmitter220sends a transmit signal to a target object, and the transmit signal is a pulse signal. The target object reflects the transmit signal, and the receiver230receives an echo signal reflected by the target object. In this embodiment of this application, the transmit signal may also be referred to as a transmit signal waveform, a transmit pulse, a transmit pulse signal, or the like, and the echo signal may also be referred to as an echo signal waveform, a receive pulse, a receive pulse signal, or the like.

A moment at which the transmitter220sends the transmit signal may be referred to as a transmit moment, and a moment at which the receiver230receives the echo signal may be referred to as a receive moment. The processing unit210may determine time of flight based on the transmit moment and the receive moment. Further, the processing unit210calculates a distance R between the radar and the target object based on a light speed and the time of flight. The distance R may be calculated according to the following formula (1):
R=c*T/2  (1)

R represents the distance between the radar and the target object, c represents the light speed, and T represents the time of flight.

FIG.4is a schematic diagram of a framework of a radar300according to an embodiment of this application. InFIG.4, a structure of the radar is described by using a laser radar as an example. The processing unit210of the radar200inFIG.2may include a signal processing and control unit310inFIG.4. The transmitter220may include a laser driver301, a laser302, a scanning component303, and a transmit end optical element304. The receiver230may include an analog-to-digital converter (analog-to-digital converter, ADC)305, a transistor impedance amplifier (transistor impedance amplifier, TIA)306, a detector307, and a receive end optical element308.

In a process of sending a signal, the signal processing and control unit310sends a pulse signal of the signal to the laser driver301, and the laser driver301modulates the pulse signal, and outputs the modulated pulse signal to the laser302. The laser302sends an optical signal with a pulse to the scanning component303. The scanning component303and the transmit end optical element304scan and shape a beam, and then sends the pulse signal to a target object.

In a process of receiving an echo signal, after focusing and shaping the received echo signal, the receive end optical element308sends the echo signal to the detector307. The echo signal is an optical signal, and after receiving the echo signal, the detector307performs photoelectric conversion to obtain a current signal. The TIA306converts the current signal into a voltage signal and sends the voltage signal to the ADC305. The ADC305performs analog-to-digital conversion on an analog voltage signal to obtain a digital signal. The signal processing and control unit310obtains a signal processed by the ADC305, and calculates a distance between the radar and the target object based on the obtained signal.

It should be noted that inFIG.4, only the laser radar is used as an example to describe a working principle of the radar, but this is not limited. A person skilled in the art can understand that the radar in this application may further be another type of radar, such as a laser range finder or a millimeter-wave radar. The radar may further include more or fewer functional units or components, provided that the radar can perform the method in the embodiments of this application.

FIG.5is a schematic flowchart of a radar ranging method according to an embodiment of this application. The method may be performed by a radar, for example, the method may be performed by the processing unit210inFIG.2, or may be performed by the signal processing and control unit310inFIG.4. As shown inFIG.5, the method includes the following steps.

S101: Obtain a pulse waveform of a transmit signal, where the transmit signal is a signal sent by a radar to a target object.

Optionally, the radar may include a laser radar, a laser range finder, a millimeter-wave radar, or another type of radar. The transmit signal may be an optical signal, a laser signal, or an electromagnetic wave signal.

Optionally, the pulse waveform of the transmit signal may be obtained in a plurality of manners. In one manner, after a signal sent by the radar to the target object is split, the pulse waveform of the transmit signal is obtained through an optical fiber reference optical path. In another manner, a pulse signal of a reference signal may be obtained through calibration before delivery of a product, and then the pulse waveform of the transmit signal is obtained in combination with a trigger moment of the transmit signal. The reference signal may be an ideal waveform signal of the transmit signal. In this embodiment of this application, a pulse waveform obtained through calibration before delivery may be referred to as a reference signal.

For example, when the radar sends a signal, a transmitted optical signal may be divided into two parts. Most of the signal (for example, 99% of energy of the optical signal) is sent to the target object through a transmitter, and a small part of the signal (for example, 1% of energy of the optical signal) is returned through an optical fiber reference optical path with a fixed delay. A signal collected from an optical fiber may be referred to as a split signal. The processing unit in the radar may perform translation processing on a pulse waveform of the split signal based on fixed delay duration, to obtain the pulse waveform of the transmit signal.

For another example, a storage device in the radar may prestore the pulse waveform of the reference signal. When the transmitter in the radar sends the transmit signal, the processing unit in the radar may obtain the pulse waveform of the reference signal from the storage device, and obtain the pulse waveform of the transmit signal in combination with the trigger moment of the transmit signal.

As a specific example, the pulse waveform of the reference signal may be obtained through a plurality of times of manual measurement in a system test phase of the radar. For example, in the system test phase, a reflector with a known reflectivity and distance is set. The transmitter of the radar is used to send the transmit signal to the reflector, and receive an echo signal reflected by the reflector. After the signal reflected by the reflector is measured and calibrated for a plurality of times, a near ideal signal waveform can be obtained. The signal waveform may be stored as the pulse waveform of the reference signal in the storage unit of the radar for subsequent comparison.

S102: Obtain a sampling sequence of an echo signal, where the echo signal is a reflection signal of the target object that is received by the radar, and the echo signal is a saturated echo signal.

In this embodiment of this application, a sampling sequence obtained by sampling the saturated echo signal may be referred to as a sampling sequence or a saturated sampling sequence of the saturated echo signal.

For example, a receiver in the radar may receive an echo signal reflected by the target object, and the echo signal is a saturated echo signal. A waveform of the saturated echo signal may be shown inFIG.3(b). The radar may perform a series of processing on the saturated echo signal, for example, photoelectric conversion, transistor impedance amplification, analog-to-digital conversion, to obtain a saturated sampling sequence obtained through sampling.

For example,FIG.6is a schematic diagram of a saturated sampling sequence according to an embodiment of this application. InFIG.6, a horizontal axis represents time, and a vertical axis represents an amplitude of a signal. A curve with a circle mark represents a saturated sampling sequence of an echo signal, and the circle mark represents a sampling point. A dashed line represents a waveform of an ideal echo signal.

S103: Determine a first timing point in at least one sampling point on a rising edge of the sampling sequence, where the first timing point is used to indicate a receive moment of the echo signal.

In this embodiment of this application, a timing point that indicates a receive moment may be first selected from the saturated sampling sequence of the echo signal, and then a timing point that indicates a transmit moment is further determined based on the timing point. For ease of differentiation, the timing point that indicates the receive moment of the echo signal may be referred to as a first timing point, and the timing point that indicates the transmit moment of the transmit signal may be referred to as a second timing point.

The saturated sampling sequence includes a rising edge and a falling edge. In principle, any sampling point may be selected from sampling points on the rising edge or the falling edge of the saturated sampling sequence as the first timing point. However, there is a phenomenon of broadening of the falling edge of the saturated echo signal, and a deformation ratio of the falling edge of the saturated sampling sequence is more severe than that of the rising edge. Therefore, to determine time of flight more precisely, the first timing point is usually selected from sampling points on the rising edge of the saturated sampling sequence.

For the saturated sampling sequence, a saturation threshold Vmaxand a minimum amplitude threshold Vminare further defined. A sampling point that reaches the saturation threshold Vmaxon the saturation sampling sequence is referred to as a saturated sampling point. A sampling point between the saturation threshold Vmaxand the minimum amplitude threshold Vminis referred to as an unsaturated sampling point.

For example, if a maximum dynamic range of a receiver for a receive signal is represented as [VL, VH], the saturation threshold Vmaxand the minimum amplitude threshold Vminmay be determined in the following calculation manner:
Vmax=VL+0.99×(VH−VL); andVmin=VL+0.01×(VH−VL).

VLrepresents a lower limit of the dynamic range of the receiver for the receive signal, and VHrepresents an upper limit of the dynamic range of the receiver for the receive signal. Factors 0.99 and 0.01 are merely examples. According to specific practice, other real numbers in the range [0, 1] may also be selected as the factors.

In this embodiment of this application, the rising edge of the saturated sampling sequence may include an unsaturated sampling point, or may include the first saturated sampling point of the saturated sampling sequence.

In some examples, if the rising edge of the sampling sequence includes a plurality of unsaturated sampling points, one sampling point may be randomly selected from the plurality of unsaturated sampling points as the first timing point.

In some examples, if the rising edge of the sampling sequence includes a plurality of unsaturated sampling points, the last unsaturated sampling point on the rising edge of the sampling sequence may be selected as the first timing point. Because the saturated echo signal is a signal on which echo signal clipping occurs, and an amplitude of the signal is lower than a normal amplitude, the last unsaturated sampling point on the rising edge may be selected as the first timing point. That is, an amplitude of the first timing point is as high as possible, so that the time of flight obtained through calculation is more precise.

In some examples, if the rising edge of the sampling sequence includes only one unsaturated sampling point, the unsaturated sampling point may be selected as the first timing point.

In some examples, if the rising edge of the sampling sequence does not include an unsaturated sampling point, the first saturated sampling point on the rising edge may be selected as the first timing point.

In this application, an appropriate timing point may be flexibly and dynamically selected on the rising edge of the saturated sampling sequence based on different degrees of saturation severity of the received saturated sampling sequence, to improve precision of determining time of flight, and further improve radar ranging precision.

S104: Determine a second timing point based on the first timing point and the pulse waveform of the transmit signal, where the second timing point is used to indicate the transmit moment of the transmit signal.

Optionally, if the saturation degree of the echo signal is relatively light, for example, the rising edge of the saturated sampling sequence includes a plurality of unsaturated sampling points, the second timing point may be determined in the first manner.

In the first manner, a fractional scale factor a may be first preset, and a delay factor ΔT is determined based on the fractional scale factor a and the first timing point. Then, the second timing point is determined based on the fractional scale factor a, the delay factor ΔT, and the pulse waveform of the transmit signal, where 0<a<1.

Specifically, the manner includes: fractionally scaling an amplitude of the sampling sequence based on the fractional scale factor a, to obtain a fractionally scaled sampling sequence, where 0<a<1; determining a moment Ta at which the fractionally scaled sampling sequence reaches a×VTD1, where VTD1represents an amplitude of the first timing point on the saturated sampling sequence; determining the delay factor ΔT, where ΔT=TD1−Ta, and TD1represents a moment of the first timing point; and calculating the second timing point based on the fractional scale factor a, the delay factor ΔT, and the pulse waveform of the transmit signal. Specifically, the pulse waveform of the transmit signal may be separately fractionally scaled and delayed based on the fractional scale factor a and the delay factor ΔT, to obtain a fractionally scaled pulse waveform and a delayed pulse waveform, and an intersection point of the two pulse waveforms is used as the second timing point. With reference toFIG.7andFIG.8, the following continues to describe the first manner of determining the timing point.

Optionally, if the saturation degree of the echo signal is relatively severe, for example, the rising edge of the saturated sampling sequence includes only one unsaturated sampling point, or even does not include an unsaturated sampling point, the second timing point may be determined in the second manner.

In the second manner, a confidence interval of the second timing point on the transmit signal waveform may be determined based on the first timing point. Specifically, the manner includes: determining the confidence interval of the second timing point on the pulse waveform of the transmit signal based on the first timing point; and determining the second timing point based on the confidence interval of the second timing point. For example, the confidence space of the second timing point may be determined based on a boundary condition. With reference toFIG.11andFIG.12, the following continues to describe the second manner of determining the timing point.

It should be noted that the second timing point may be located on the pulse waveform of the transmit signal, or may not be located on the pulse waveform of the transmit signal. For example, in the first manner of determining the second timing point, the second timing point is the intersection point between the fractionally scaled transmit signal and the delayed transmit signal, that is, the second timing point is located on a pulse waveform of the fractionally scaled transmit signal or is located on a waveform of the delayed transmit signal. In the second manner of determining the second timing point, the second timing point is located on the pulse waveform of the transmit signal.

S105: Determine a distance between the radar and the target object based on the first timing point and the second timing point.

Optionally, after a moment TD1of the first timing point and a moment TD2of the second timing point are determined, it may be determined that the time of flight is T=TD1−TD2, and the distance R between the radar and the target object may be determined according to the following formula (2):
R=(TD1−TD2)×c/2  (2)

TD1represents the moment of the first timing point, TD2represents the moment of the second timing point, and c represents a light speed.

In this embodiment of this application, in a radar ranging process, after the sampling sequence of the saturated echo signal is obtained, the first timing point may be selected from the at least one sampling point on the rising edge of the sampling sequence, and the first timing point is used as the receive moment of the echo signal. Then, the second timing point is determined based on the first timing point and the waveform of the transmit signal, and the second timing point is used as the transmit moment of the transmit signal. Because the first timing point is selected from the sampling points on the rising edge of the saturated sampling sequence, moment information and amplitude information that correspond to the first timing point are true information on the echo signal. In addition, in the foregoing solution, a location of the first timing point is first determined, and then a location of the second timing point is determined based on the location of the first timing point. In this manner, the timing point is determined based on the true information of the echo signal as much as possible, so that precision of determining time of flight can be improved when the saturated echo signal is received, thereby further improving radar ranging precision. If a preset timing point is a fixed location on the saturated echo signal and the transmit signal, a location of a non-sampling point on the saturated sampling sequence may be selected as the timing point. This makes moment information and amplitude information of the timing point not precise, thereby reducing radar ranging precision.

FIG.7is a schematic flowchart of a radar ranging method according to another embodiment of this application.FIG.7shows a method for determining a timing point based on a fractional scale factor a and a delay factor ΔT. The method inFIG.7is applicable to a scenario in which a saturation degree of an echo signal is relatively light, for example, a case in which a rising edge of a saturated sampling sequence includes a plurality of unsaturated sampling points. As shown inFIG.7, the method includes the following steps.

S601: Obtain a pulse waveform of a transmit signal.

For example, a storage device in a radar may prestore a pulse waveform of a reference signal. A processing unit in the radar may obtain the pulse waveform of the reference signal from the storage device, and obtain the pulse waveform of the transmit signal in combination with a trigger moment of the transmit signal. Alternatively, after a signal sent by the radar to a target object is split, a small part of the signal that is split is returned to the radar through a reference optical path with a fixed delay, and the part of the signal is a split signal. The radar may translate a waveform of the split signal based on the fixed delay to obtain the pulse waveform of the transmit signal.

S602: Obtain a sampling sequence of a saturated echo signal.

For example, the sampling sequence is a sampling sequence after ADC sampling.

Content of S601and S602is the same as or similar to content of S101or S102inFIG.5. For brevity, details are not described herein again.

S603: Select a first timing point from unsaturated sampling points on a rising edge of the sampling sequence.

For example, a first sampling point that is the first sampling point, on the rising edge, greater than a minimum amplitude threshold Vminis first determined, and then a second sampling point that is the last sampling point, on the rising edge, less than a saturation threshold Vmaxis determined. The first sampling point, the second sampling point, and a sampling point located between the first sampling point and the second sampling point are unsaturated sampling points located on the rising edge of the sampling sequence. A sampling point may be randomly selected from the unsaturated sampling points on the rising edge as the first timing point.

As shown inFIG.6, assuming Vmin=5 and Vmax=120, the unsaturated sampling points on the rising edge are two sampling points at a moment6and a moment7. The sampling point located at the moment7may be selected as the first timing point, and the moment of the first timing point is recorded as TD1=7. In this case, an amplitude corresponding to the first timing point is VTD1=80.

S604: Determine a fractional scale factor a and a delay factor ΔT.

Specifically, the fractional scale factor a may be first determined, and an original sampling sequence is fractionally scaled based on the fractional scale factor a, to calculate an amplitude of the first timing point on the fractionally scaled saturated sampling sequence, that is, a×VTD1. Then, a moment at which the rising edge of the original sampling sequence signal reaches a×VTD1is calculated, and the moment is recorded as Ta. In this way, the delay factor ΔT is expressed as ΔT=TD1−Ta.

Any value between 0 and 1 may be selected for the fractional scale factor a. For example, the fractional scale factor a inFIG.6is a=0.5. As shown inFIG.6, a curve with a square mark is used to represent a sampling sequence after being fractionally scaled by ½. The amplitude of the first timing point on the fractionally scaled sampling sequence is a×VTD1=40. It can be learned fromFIG.6that when the moment Ta at which the rising edge of the original sampling sequence reaches a*VTD1=40 is Ta=6.4, the delay factor ΔT=TD1−Ta=7−6.4=0.6.

It should be noted that, to obtain a more precise moment, interpolation may be performed on an original sampling sequence curve, to obtain a sampling sequence after interpolation, and the moment Ta is selected from the sampling sequence after interpolation. For example, a curve with an x mark inFIG.6represents a sequence obtained by interpolating the sampling sequence. An interpolation manner is not limited in this embodiment of this application. For example, an interpolation manner such as cubic spline (cubic spline) interpolation or linear (linear) interpolation may be used.

S605: Calculate a second timing point based on the fractional scale factor a, the delay factor ΔT, and the pulse waveform of the transmit signal.

In a process of calculating the second timing point, the pulse waveform of the transmit signal may be first multiplied by the fractional scale factor a, to obtain a fractionally scaled pulse waveform of the transmit signal. Then, the pulse waveform of the transmit signal is translated to the right based on the delay factor ΔT, to obtain a delayed pulse waveform of the transmit signal. Then, an intersection point between the fractionally scaled pulse waveform of the transmit signal and the delayed pulse waveform of the transmit signal is determined as the second timing point.

For example,FIG.8is a schematic diagram of a waveform of a transmit signal according to an embodiment of this application. InFIG.8, a horizontal axis represents time, and a vertical axis represents an amplitude. A solid line inFIG.8represents a transmit signal that is fractionally scaled by 50%, that is, a fractional scale factor a is 0.5. A dashed line represents a delayed transmit signal, and a delay factor ΔT is 0.6. An intersection point between the fractionally scaled transmit signal waveform and the delayed transmit signal waveform is the second timing point of the transmit signal. It can be learned fromFIG.8that the intersection point is a moment17, that is, the second timing point is located at the moment17.

Optionally, the intersection point may be determined according to the following formula (3):

t^=argmint❘"\[LeftBracketingBar]"f⁢(t-Δ⁢T)-a×f⁢(t)❘"\[RightBracketingBar]",(3)

f(t−ΔT) represents the delayed pulse waveform, a×f(t) represents the fractionally scaled pulse waveform, and t represents a moment of the intersection point. The formula (3) indicates that t is a moment at which a difference between the two pulse signals is the smallest.

S606: Calculate time of flight based on the first timing point and the second timing point.

The time of flight may be represented as T=TTD1−TD2.

S607: Calculate a distance R between the radar and the target object based on the time of flight.

For example, the distance R is calculated according to the formula R=(TTD1−TD2)*c/2.

In this embodiment of this application, in a radar ranging process, after the sampling sequence of the saturated echo signal is obtained, the first timing point may be selected from the sampling points of the sampling sequence, the delay factor ΔT is determined based on the preset fractional scale factor a and the first timing point, and then the second timing point is determined based on the fractional scale factor a and the delay factor ΔT. Because the first timing point is selected from the sampling points on the rising edge of the saturated sampling sequence, moment information and amplitude information that correspond to the first timing point are true information on the echo signal. In this manner, when the saturated echo signal is received, precision of determining the time of flight is improved, thereby further improving radar ranging precision. In addition, the timing point is determined based on the fractional scale factor a and the delay factor ΔT, and this can reduce impact of the saturated echo signal on determining a location of the timing point, improve precision of determining a relative location of the second timing point, and further improve radar ranging precision.

When a saturation degree of the echo signal is severe, a quantity of unsaturated sampling points on the rising edge of the echo signal is quite small, and there is also a relatively large error in the method for determining the timing point based on the fractional scale factor a and the delay factor ΔT. Consequently, a corresponding timing point cannot be precisely found on the transmit signal. This case is referred to as timing ambiguity.

FIG.9is a schematic diagram of a saturated sampling sequence according to another embodiment of this application. InFIG.9, a horizontal axis represents time, and a vertical axis represents an amplitude. A solid line with a circle mark represents a saturated sampling sequence with a relatively severe saturation degree, and a solid line with a pentagonal star mark represents a saturated sampling sequence with a relatively light saturation degree. As shown inFIG.9, when a saturation degree is severe, there is only one unsaturated sampling point on a rising edge of a sampling sequence, namely, a sampling point at a moment157. An amplitude (amplitude>Vmax) of a sampling point at a moment158is saturated, and an amplitude (amplitude<Vmin) of a sampling point at a moment156is still quite low. In this case, there are quite few sampling points available for interpolation, and a deviation brought by interpolation is also relatively high. Consequently, there is a relatively large error in a method for determining a timing point based on a fractional scale factor a and a delay factor ΔT.

FIG.10(a)andFIG.10(b)are schematic diagrams of saturated sampling sequences according to another embodiment of this application. InFIG.10(a)andFIG.10(b), a horizontal axis represents time, and a vertical axis represents an amplitude.FIG.10(a)andFIG.10(b)show schematic diagrams of ideal echo signals and corresponding saturated sampling sequences of different waveforms. A solid line in the figure represents an ideal echo signal, and a curve with an x mark represents a sampling sequence of a saturated echo signal received by a radar. A rising edge part of the saturated sampling sequence inFIG.10(a)is the same as that inFIG.10(b). It can be learned that timing points of same saturated sampling sequences may correspond to different locations of transmit signals. Therefore, when a saturation degree is relatively severe, it is difficult to determine a timing point corresponding to the saturated echo signal on the transmit signal based on the saturated sampling sequence of the echo signal. This causes timing ambiguity.

To improve timing ambiguity, this embodiment of this application further provides a manner of determining a second timing point on a transmit signal based on a confidence interval, to reduce timing ambiguity. The following describes this method with reference toFIG.11andFIG.12.

FIG.11is a schematic diagram of a radar ranging method according to another embodiment of this application.FIG.11shows a method for determining a second timing point based on a confidence interval. The method is applicable to a scenario in which a saturation degree of an echo signal is relatively severe, for example, a case in which a rising edge of a saturated sampling sequence includes only one saturated sampling point or does not include an unsaturated sampling point. As shown inFIG.11, the method includes the following steps.

S701: Obtain a pulse waveform of a transmit signal.

For example, a storage device in a radar may prestore a pulse waveform of a reference signal. A processing unit in the radar may obtain the pulse waveform of the reference signal from the storage device, and obtain the pulse waveform of the transmit signal in combination with a trigger moment of the transmit signal. Alternatively, after a signal sent by the radar to a target object is split, a small part of the signal that is split is returned to the radar through a reference optical path with a fixed delay, and the part of the signal is a split signal. The radar may translate a waveform of the split signal based on a fixed delay to obtain the pulse waveform of the transmit signal.

S702: Obtain a sampling sequence of a saturated echo signal.

For example, the sampling sequence is a sampling sequence after ADC sampling.

Content of S701and S702is the same as or similar to content of S101or S102inFIG.5. For brevity, details are not described herein again.

S703: Select a first timing point from sampling points of the sampling sequence.

For example, a first sampling point that is the first sampling point, on a rising edge of the sampling sequence, greater than a minimum amplitude threshold Vminis first determined, and then a second sampling point that is the last sampling point, on the rising edge, less than a saturation threshold Vmaxis determined. A sampling point located between the first sampling point and the second sampling point is an unsaturated sampling point located on the rising edge of the echo signal. A sampling point may be randomly selected from unsaturated sampling points as the first timing point.

Optionally, if the rising edge of the sampling sequence includes only one unsaturated sampling point, the unsaturated sampling point may be selected as the first timing point. If a saturation degree is severe, and the rising edge of the sampling sequence does not include an unsaturated sampling point, the first saturated sampling point on the rising edge of the sampling sequence may be selected as the first timing point.

For example, inFIG.9, if a saturated sampling sequence with a circle mark includes only one unsaturated sampling point, the unsaturated sampling point may be selected as the first timing point. A moment of the first timing point is TD1=157, and an amplitude is VTD1=30.

S704: Determine a confidence space of the second timing point on the pulse waveform of the transmit signal.

The confidence space of the second timing point may be determined by using a boundary condition satisfied by the second timing point. For example,

the boundary condition may include but is not limited to at least one of the following: An amplitude of a previous sampling point of the first timing point is 0 (amplitude<Vmin); a next sampling point of the first timing point is a saturated sampling point (amplitude>Vmax); and that an amplitude of the transmit signal at a moment T5reaches the saturation threshold Vmaxis a little probability event, and the moment T5may be a preset moment in a time interval corresponding to the pulse waveform of the transmit signal. The moment T5may be any moment in the foregoing time interval.

It should be noted that the foregoing boundary condition is merely used as an example, and the confidence space of the second timing point may also be determined based on another boundary condition satisfied by the second timing point.

FIG.12is a schematic diagram of a confidence interval of a second timing point according to an embodiment of this application. InFIG.12, a horizontal axis represents time, and a vertical axis represents an amplitude. As shown inFIG.12, a first confidence space [T1, T2] with a relatively large range may be first calculated, and then a left boundary and a right boundary of the first confidence space are gradually fractionally scaled until a confidence interval [T3, T4] of the second timing point is obtained. Next, a process of determining the confidence space is described.

(1) Determine a left boundary moment T1of the first confidence space [T1, T2] of the second timing point.

In steps (1) and (2), it may be understood that the first confidence interval [T1, T2] of the second timing point is determined based on a first boundary condition, where the first boundary condition includes: An amplitude of a previous sampling point of the first timing point is 0.

T1is a moment at which an amplitude of the transmit signal reaches a threshold Vtx,min, Vtx,min=k×VTD1, VTD1represents an amplitude of the first timing point on the saturated sampling sequence, k is a preset constant, and 0<k<1.

Optionally, V may be selected as far as possible as a location (where an amplitude is 0) at a previous sampling point close to the first timing point on the transmit signal, that is, Vtx,minmay be a value as small as possible (or a value as close to 0 as possible). An amplitude of k may be determined based on specific practice. As an example, k may be set to be less than or equal to the following values: 0.1%, 1%, 2%, 3%, 5%, 8%, 10%, 20%, 30%, and the like.

For example, inFIG.9, the amplitude of the previous sampling point of the first timing point is 0, and the amplitude VTD1of the first timing point is 30. It is assumed that k=2%, and Vtx,min=VT0+k×(VTD1−VT0)=2%×30=0.6. In this case, inFIG.12, the left boundary moment T1of the first confidence interval at the second timing point is a moment at which VT1=0.6.

(2) Determine a right boundary moment T2of the first confidence space [T1, T2] of the second timing point.

T2=T1+TS, and TSrepresents a sampling time interval of the echo signal. For example, as shown inFIG.12, the sampling interval of the echo signal is TS=1 ns (nanosecond). It is assumed that a moment of the second timing point is represented by TD2. In this case, TD2∈[T1, T2].

Theoretically, the first timing point that is of the echo signal and that corresponds to a location (namely, the second timing point) of the transmit signal needs to be located in the interval [T1, T2]. Because it can be learned from the saturated sampling sequence that the location of the first timing point is a value greater than 0, it can be determined that the location that is of the second timing point and that corresponds to the transmit signal is necessarily at a location on the right of T1. Because the amplitude Vtx,mincorresponding to the moment T1of the transmit signal is a value close to zero, it may be considered that an amplitude of the sampling point on the left of T1is 0. In addition, it can be learned fromFIG.9that, an amplitude of the sampling point at TD1−TS=157−1=156 is 0 or close to 0. Therefore, the location of the second timing point on the transmit signal is necessarily located on the left of the moment T2. Otherwise, the previous sampling point of the first timing point is located on the right of T1, and the amplitude of the previous sampling point of the first timing point is greater than 0. This is inconsistent with the fact.

It should be noted that after step (2) is completed, the first confidence space [T1, T2] may be used as the confidence interval of the second timing point. Alternatively, starting from step (3), the left boundary and the right boundary of the first confidence interval [T1, T2] may be further fractionally scaled, to obtain a confidence space with a smaller range, thereby obtaining a more precise second timing point.

(3) Fractionally scale the right boundary of the confidence interval of the second timing point to a moment T4.

In step (3), it may be understood that a right boundary moment T4of a confidence interval [T3, T4] of the second timing point is determined based on the first confidence interval [T1, T2] and a second boundary condition, where the second boundary condition includes: A next sampling point of the first timing point is a saturated sampling point.

Optionally, movement to the left starting from T2is performed, to detect whether different time points can be excluded from the confidence interval. Assuming that a current detected time point is TX, and the amplitude of the transmit signal is represented as VTX(TX), it may be detected whether TXsatisfies a condition of the confidence interval according to formula (4):

V⌢=VTD⁢1⁢VTX(TX+TS)VTX(TX)(4)

TXrepresents a moment on the left of the moment T1, VTD1represents an amplitude of the first timing point on the saturated sampling sequence, VTX(TX) represents an amplitude of the transmit signal at the moment TX, and VTX(TX+TS) represents an amplitude of the transmit signal at the moment TX+TS. TSrepresents a sampling interval of the saturated sampling sequence, and {circumflex over (V)} represents a predicted value of the saturated sampling sequence of the echo signal at a next sampling point of the first timing point.

The moment T4is the moment TXat which {circumflex over (V)} reaches the saturation threshold Vmaxof the saturated sampling sequence. Because a next sampling point of the second timing point is a saturated sampling point, if {circumflex over (V)} does not reach the saturation threshold Vmaxof the saturated sampling sequence, it indicates that the currently detected moment TXdoes not satisfy the confidence interval. Because a next sampling point after the first timing point of the known echo signal is a saturated sampling point, and the moment TXcannot satisfy this condition, next, a moment on the left of the moment TXmay be continued to be detected until a moment at which the predicted value {circumflex over (V)} reaches the saturation threshold Vmaxis found, and the moment may be recorded as T4.

After step (3), the confidence interval of the second timing point may be fractionally scaled to [T1, T4].

(4) Fractionally scale the left boundary of the confidence interval of the second timing point to a moment T3.

In step (4), it may be understood that a left boundary moment T3of the confidence interval [T3, T4] of the second timing point is determined based on the first confidence interval [T1, T2] and a third boundary condition, where the third boundary condition includes: That an amplitude of the transmit signal at a preset saturation alert point reaches the saturation threshold Vmaxis a little probability event.

First, a saturation alert point is selected on the transmit signal, the saturation alert point is at a moment T5at which the signal is transmitted, and it is preset that the following case is a little probability event: The echo signal is severely saturated, so that the amplitude VTX(T5) of the transmit signal at the moment T5corresponding to the saturation alert point reaches a saturation degree. Therefore, a case in which VTX(T5) reaches the saturation degree may be not considered. The moment T5may be a preset moment in a time interval corresponding to the pulse waveform of the transmit signal. It should be noted that a selection condition of the moment T5is not limited in this application. InFIG.12, the moment T5is located in the first confidence space [T1, T2]. However, the moment T5may also be set at a location of the moment T5outside the first confidence space [T1, T2].

Based on the foregoing third boundary condition, movement to the right starting from the moment T1is performed, to detect whether different time points can be excluded from the confidence interval. It is assumed that a current detected moment is Ty, and whether Tycauses the saturation alert point at a corresponding location on the sampling sequence may be determined. If saturation is not caused, this satisfies a preset condition, and Tybelongs to the confidence interval. If saturation is caused, this does not satisfy a preset condition, and Tyis outside the confidence interval. The condition that whether Tysatisfies the confidence interval may be calculated according to formula (5):

V⌢T⁢5=VTD⁢1⁢VTX(T⁢5)VTX(Ty),(5)

VTD1represents an amplitude of the saturated sampling sequence of the echo signal at the first timing point, VTX(Ty) represents an amplitude of the transmit signal at the moment Ty, VTX(T5) represents an amplitude of the transmit signal at the moment T5, and {circumflex over (V)}T5indicates a predicted value of an amplitude of the saturation alert point on the sampling sequence.

If {circumflex over (V)}T5exceeds the saturation threshold Vmax, it indicates that the currently detected moment Tydoes not belong to the confidence interval. Because if the second timing point is located at Vy, the saturation alert point T5reaches the saturation threshold Vmax, and this does not satisfy the preset condition. In this case, a moment on the right of current Tymay continue to be detected according to formula (5) until the moment Tyat which the predicted value {circumflex over (V)}T5reaches the saturation threshold Vmaxis found, and the moment Ty is recorded as the moment T3.

After step (4), the confidence interval of the second timing point may be fractionally scaled to [T3, T4], where [T3, T4]∈[T1, and T2].

S705: Determine the second timing point based on the confidence space of the second timing point.

The second timing point may be determined in a plurality of manners. For example, any moment in the confidence space [T3, T4] may be selected as the second timing point. Alternatively, an average value of the confidence space [T3, T4] may be selected as the second timing point.

For example, the moment of the second timing point may be represented as

TD⁢2=T⁢3+T⁢42,
where TD2represents the moment of the second timing point, T3represents the left boundary moment of the confidence interval, and T4represents the right boundary moment of the confidence interval.

S706: Calculate the distance between the radar and the target object based on the first timing point and the second timing point.

For example, the second timing point is used as an average value of the confidence space [T3, T4], and the distance may be calculated according to formula (6).

R=(TD⁢1-T⁢3+T⁢42)2×c(6)

R represents the distance, TD1represents the moment of the first timing point, TD2represents the moment of the second timing point, and c represents the light speed.

In this embodiment of this application, the first timing point may be first selected on the sampling sequence of the saturated echo signal, then the confidence interval of the second timing point is determined on the transmit signal based on the first timing point, and the second timing point is determined based on the confidence interval, to calculate the distance between the radar and the target object. When the saturation degree of the saturated echo signal is relatively severe, the confidence space of the second timing point is calculated by a boundary condition, and the location of the second timing point is determined. This can reduce timing ambiguity and improve radar ranging precision.

FIG.13is a schematic diagram of a structure of a computing device900according to another embodiment of this application. The computing device900may be configured to perform the method or the step performed by the processing unit210or the signal processing and control unit310in the method embodiments of this application. For example, the computing device900may perform the method described inFIG.5,FIG.7, orFIG.11. The computing device900includes:a communications interface910;a memory920, configured to store a computer program; anda processor930, configured to execute the computer program in the memory920.
When the program is executed, the processor930is configured to: obtain a pulse waveform of a transmit signal, where the transmit signal is a signal sent to a target object by a radar; obtain a sampling sequence of an echo signal, where the echo signal is a reflection signal of the target object that is received by the radar, and the echo signal is a saturated echo signal; determine a first timing point in at least one sampling point on a rising edge of the sampling sequence, where the first timing point is used to indicate a receive moment of the echo signal; determine a second timing point based on the first timing point and the pulse waveform of the transmit signal, where the second timing point is used to indicate a transmit moment of the transmit signal; and calculate a distance between the radar and the target object based on the first timing point and the second timing point.

It should be understood that the computing device shown inFIG.13may be a device, a chip, or a circuit, for example, a chip or a circuit that may be disposed inside a terminal device or a vehicle-mounted device. The processor930, the memory920, and the communications interface910are connected through a bus system. In an implementation, the processor930may be implemented through a dedicated processing chip, a processing circuit, a processor, or a general-purpose chip. For example, the processor930may include a central processing unit (central processor unit, CPU), a combination of one or more microprocessors, a digital signal processor (digital signal processing, DSP), and the like.

FIG.14is a schematic diagram of a structure of a device1000according to another embodiment of this application. The device1000may be configured to perform the method or the step performed by the processing unit210or the signal processing and control unit310in the method embodiments of this application. For example, the device1000may perform the method described inFIG.5,FIG.7, orFIG.11. The device1000includes: a first obtaining unit1010, configured to obtain a pulse waveform of a transmit signal, where the transmit signal is a signal sent to a target object by a radar; a second obtaining unit1020, configured to obtain a sampling sequence of an echo signal, where the echo signal is a reflection signal of the target object that is received by the radar, and the echo signal is a saturated echo signal; a first determining unit1030, configured to determine a first timing point in at least one sampling point on a rising edge of the sampling sequence, where the first timing point is used to indicate a receive moment of the echo signal; a second determining unit1040, configured to determine a second timing point based on the first timing point and the pulse waveform of the transmit signal, where the second timing point is used to indicate a transmit moment of the transmit signal; and a computing unit1050, configured to calculate a distance between the radar and the target object based on the first timing point and the second timing point.

A person of ordinary skill in the art may be aware that, in combination with the examples described in the embodiments disclosed in this specification, units and algorithm steps may be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed by hardware or software depends on particular applications and design constraints of the technical solutions. A person skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of this application.

It may be clearly understood by a person skilled in the art that, for convenient and brief description, for a detailed working process of the foregoing system, apparatus, and unit, refer to a corresponding process in the foregoing method embodiments. Details are not described herein again.

In the several embodiments provided in this application, it should be understood that the disclosed system, apparatus, and method may be implemented in another manner. For example, the described apparatus embodiment is merely an example. For example, division into the units is merely logical function division and may be other division in an actual implementation. For example, a plurality of units or components may be combined or integrated into another system, or some features may be ignored or may not be performed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented through some interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in an electronic form, a mechanical form, or another form.

The foregoing units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on a plurality of network units. Some or all of the units may be selected based on actual requirements to achieve the objectives of the solutions of the embodiments.

In addition, function units in the embodiments of this application may be integrated into one processing unit, or each of the units may exist alone physically, or two or more units may be integrated into one unit.

When the functions are implemented in a form of a software function unit and sold or used as an independent product, the functions may be stored in a computer-readable storage medium. Based on such an understanding, the technical solutions of this application essentially, or the part contributing to the conventional technology, or some of the technical solutions may be implemented in a form of a software product. The computer software product is stored in a storage medium, and includes several instructions for instructing a computer device (which may be a personal computer, a server, a network device, or the like) to perform all or some of the steps of the methods described in the embodiments of this application. The foregoing storage medium includes any medium that can store program code, for example, a USB flash drive, a removable hard disk, a read-only memory (read-only memory, ROM), a random access memory (random access memory, RAM), a magnetic disk, or an optical disc.

The foregoing descriptions are merely specific implementations of this application, but are not intended to limit the protection scope of this application. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in this application shall fall within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.