A method and apparatus for near field estimation

Abstract

The application provides a near-field estimation method and device, the method is applied to a multiple-input multiple-output (MIMO) radar, an antenna array of the MIMO radar comprises M transmitting antennas and N receiving antennas, M is a positive integer, and N is a positive integer, and the method comprises the following steps: measuring a first distance between a reference receiving antenna and a target, the reference receiving antenna being one of the N receiving antennas; determining a second distance between a jth receiving antenna and the target according to the first distance, wherein j is a positive integer less than or equal to N; determining a wave path difference of a first virtual receiving antenna and a second virtual receiving antenna according to the first distance and the second distance, wherein the first virtual receiving antenna is determined by a reference transmitting antenna and the reference receiving antenna, the reference transmitting antenna being one of the M transmitting antennas, and the second virtual receiving antenna is determined by an ith transmitting antenna and the jth receiving antenna, i being a positive integer less than or equal to M; and determining an angle of arrival of the first virtual receiving antenna according to the wave path difference.

Description

[0001] This application is a divisional application of the original application with the application number 202080004958.1 and the original filing date of January 8, 2020, and the entire contents of the original application are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the field of wireless, and in particular to a near-field estimation method and device. BACKGROUND

[0003] Millimeter wave vehicle-mounted radar is one of the indispensable sensors in the field of automatic driving due to its all-weather detection capability. In order to obtain high angular resolution, using multiple-input multiple-output (MIMO) radar technology can obtain a large array aperture under the condition of limited number of antennas. Time-division multiplexing (TDM) MIMO transmission mode has the advantages of simple hardware implementation and low mutual coupling effect, and has become an important research direction of vehicle-mounted millimeter wave MIMO radar. Frequency modulated continuous waveform (FMWC) is a commonly used vehicle-mounted radar transmission waveform of TDM-MIMO.

[0004] The vehicle-mounted radar completes the positioning of the target by measuring the range and angle of the target, i.e. angle of arrival (AOA) estimation. When estimating the angle, the wavefront can be assumed as a plane wave under the far-field condition. However, under the near-field condition, the wavefront should be considered as a spherical wave. For example, for a MIMO radar of 77GHz frequency band, if there are 256 virtual antennas in the horizontal direction, the aperture of the virtual antenna is about 0.5m. When the distance between the radar and the target is greater than 64.2m, it is suitable for the far-field condition, and when it is less than 64.2m, it is suitable for the near-field condition. Therefore, the AOA estimation under the near-field condition needs to be applied to the targets within about 64.2m.

[0005] Fast fourier transform (FFT) algorithm is a commonly used angle estimation algorithm of existing vehicle-mounted radar, but FFT can only be used for far-field estimation and cannot be used for near-field estimation. In the prior art near-field AOA algorithm, the spherical wave path difference calculation is complex, and it is not suitable for any number of antennas, it is difficult to calibrate the near-field of the antenna in a darkroom with limited size, and it is difficult to generate a steering vector for each antenna element, resulting in a decline in AOA estimation accuracy. SUMMARY

[0006] The application provides a near-field estimation method and device, in which the actual physical positions of multiple transmitting antennas are considered, so that the target angle of arrival can be more accurately estimated, and the problem of angle spectrum dispersion does not occur.

[0007] In a first aspect, a method for angle of arrival estimation is provided, which is applied to a multiple-input multiple-output (MIMO) radar, an antenna array of the MIMO radar includes M transmitting antennas and N receiving antennas, M is a positive integer, and N is a positive integer, and the method includes: measuring a first distance between a reference receiving antenna and a target, the reference receiving antenna being one of the N receiving antennas; determining a second distance between a jth receiving antenna and the target according to the first distance, j being a positive integer less than or equal to N; determining a path difference of a first virtual receiving antenna and a second virtual receiving antenna according to the first distance and the second distance, the first virtual receiving antenna being determined by a reference transmitting antenna and the reference receiving antenna, the reference transmitting antenna being one of the M transmitting antennas, and the second virtual receiving antenna being determined by an ith transmitting antenna and the jth receiving antenna, i being a positive integer less than or equal to M; and determining an angle of arrival of the first virtual receiving antenna according to the path difference.

[0008] According to the embodiments of the application, MN virtual receiving antennas can be determined by the M transmitting antennas and the N receiving antennas, the path difference of the first virtual receiving antenna and the second virtual receiving antenna can be determined according to the first distance and the second distance, the actual physical positions of the multiple transmitting antennas and the virtual receiving antennas are considered in combination, the angle of arrival of the target can be more accurately estimated, and the problem of angle spectrum dispersion does not occur.

[0009] In combination with the first aspect, in some implementations of the first aspect, the determining the angle of arrival of the target according to the path difference includes: determining a phase difference of the first virtual receiving antenna and the second virtual receiving antenna according to the path difference; constructing a steering vector according to the phase difference; and determining the angle of arrival of the first virtual receiving antenna according to the steering vector.

[0010] According to the embodiments of the application, a method for angle of arrival estimation according to a path difference is provided, and the angle of arrival of the first virtual receiving antenna can be obtained according to the method.

[0011] With reference to the first aspect, in some implementations of the first aspect, the determining the path difference of the first virtual receiving antenna and the second virtual receiving antenna according to the first distance and the second distance comprises: determining a first path of the first virtual receiving antenna; determining a second path of the second virtual receiving antenna; and determining the path difference of the first virtual receiving antenna and the second virtual receiving antenna according to the first path and the second path; wherein the determining the second path of the second virtual receiving antenna comprises: determining a third distance between the target and the ith transmitting antenna according to the first distance; and determining the second path of the second virtual receiving antenna according to the second distance and the third distance.

[0012] According to the embodiments of the present application, the second path of the second virtual receiving antenna can be determined according to the second distance between the jth receiving antenna and the target and the third distance between the ith transmitting antenna and the target, and the angle of arrival of the first virtual receiving antenna can be further estimated.

[0013] With reference to the first aspect, in some implementations of the first aspect, the determining the first path of the first virtual receiving antenna comprises: determining a fourth distance between the reference transmitting antenna and the target according to the first distance; and determining the first path of the first virtual receiving antenna according to the first distance and the fourth distance.

[0014] According to the embodiments of the present application, the second path of the second virtual receiving antenna can be determined according to the first distance between the reference receiving antenna and the target and the fourth distance between the reference transmitting antenna and the target.

[0015] With reference to the first aspect, in some implementations of the first aspect, the determining the second distance between the jth receiving antenna and the target according to the first distance comprises: determining the second distance between the jth receiving antenna and the target according to the first distance and a fifth distance between the reference receiving antenna and the jth receiving antenna.

[0016] According to the embodiments of the present application, the second distance between the jth receiving antenna and the target can be calculated by the first distance between the reference receiving antenna and the target and the fifth distance between the reference receiving antenna and the jth receiving antenna and by using geometric relationship.

[0017] With reference to the first aspect, in some implementations of the first aspect, the N receiving antennas are arranged at equal intervals.

[0018] According to the embodiments of the present application, when the N receiving antennas are arranged at equal intervals, the fifth distance between the reference receiving antenna and the jth receiving antenna can be determined according to the intervals between the receiving antennas.

[0019] In some implementations of the first aspect, the phase difference satisfies the following formula:

[0020]

[0021] wherein, is a phase difference between the first virtual receiving antenna and the second virtual receiving antenna, λ is a working wavelength of an antenna array of the MIMO radar, R1 is the first distance, R j is the second distance, L1 is the fourth distance, L i is the third distance.

[0022] According to the embodiments of the present application, when the angle of arrival of the first virtual receiving antenna is estimated, the actual physical positions of the second virtual receiving antenna and the first virtual receiving antenna are taken into account, so that the estimation accuracy of the angle of arrival of the first virtual receiving antenna can be improved.

[0023] In some implementations of the first aspect, the phase difference satisfies the following formula:

[0024]

[0025] wherein, is a phase difference between the first virtual receiving antenna and the second virtual receiving antenna, λ is a working wavelength of an antenna array of the MIMO radar, r1 is a measured value of the first distance, θ is the angle of arrival of the first virtual receiving antenna, d is a half wavelength of the antenna array of the MIMO radar, the kth virtual receiving antenna is the second virtual receiving antenna, and k is a positive integer less than or equal to MxN.

[0026] According to the embodiments of the present application, it is assumed that the transmitting antennas of all virtual receiving antennas are the same transmitting antenna, at this time, the change of the wave path difference caused by the transmitting antenna is ignored, and this calculation method is simpler.

[0027] In some implementations of the first aspect, the method further comprises:

[0028] According to the phase difference, the angle of arrival is accurately estimated, and the phase difference satisfies the following formula:

[0029]

[0030] wherein, q is a distance between the qth virtual receiving antenna and the q-1th virtual receiving antenna when the angle of arrival is θ.

[0031] According to the embodiment of the present application, with the increase of the aperture of the antenna array of the MIMO radar, the d becomes a variable from a constant under the condition of the near field, and after the d is represented by θ, more accurate angle of arrival estimation can be performed.

[0032] With reference to the first aspect, in some implementations of the first aspect, the method further includes: determining a phase calibration coefficient of the calibration of the antenna array of the MIMO radar according to the phase difference and a measured value of the phase difference before calibration.

[0033] According to the embodiment of the present application, the phase calibration coefficient obtained by using the theoretical wave path difference / phase difference of the embodiment of the present application for calculation is more accurate, and thus a more accurate angle of arrival estimation result can be obtained.

[0034] The second aspect provides a device for angle of arrival estimation, which is located in a multiple-input multiple-output (MIMO) radar, and an antenna array of the MIMO radar includes M transmitting antennas and N receiving antennas, M is a positive integer, and N is a positive integer, and the device includes: a measuring unit configured to measure a first distance between a reference receiving antenna and a target, the reference receiving antenna being one of the N receiving antennas; a calculating unit configured to determine a second distance between a jth receiving antenna and the target according to the first distance, j being a positive integer less than or equal to N; the calculating unit is further configured to determine a wave path difference of a first virtual receiving antenna and a second virtual receiving antenna according to the first distance and the second distance, the reference transmitting antenna being one of the M transmitting antennas, wherein the first virtual receiving antenna is determined by the reference transmitting antenna and the reference receiving antenna, and the second virtual receiving antenna is determined by an ith transmitting antenna and the jth receiving antenna, i being a positive integer less than or equal to M; and the calculating unit is further configured to determine an angle of arrival of the first virtual receiving antenna according to the wave path difference.

[0035] With reference to the second aspect, in some implementations of the second aspect, the calculating unit is further configured to determine the angle of arrival of the first virtual receiving antenna according to the wave path difference includes: determining a phase difference of the first virtual receiving antenna and the second virtual receiving antenna according to the wave path difference; constructing a steering vector according to the phase difference; and determining the angle of arrival of the first virtual receiving antenna according to the steering vector.

[0036] With reference to the second aspect, in some implementations of the second aspect, the calculating unit is further configured to determine the path difference of the first virtual receiving antenna and the second virtual receiving antenna according to the first distance and the second distance includes: determining a first path of the first virtual receiving antenna; determining a second path of the second virtual receiving antenna; determining the path difference of the first virtual receiving antenna and the second virtual receiving antenna according to the first path and the second path; wherein the determining the second path of the second virtual receiving antenna includes: determining a third distance between the i th transmitting antenna and the target according to the first distance; determining the second path of the second virtual receiving antenna according to the second distance and the third distance.

[0037] With reference to the second aspect, in some implementations of the second aspect, the determining the first path of the first virtual receiving antenna includes: determining a fourth distance between the reference transmitting antenna and the target according to the first distance; determining the first path of the first virtual receiving antenna according to the first distance and the fourth distance.

[0038] With reference to the second aspect, in some implementations of the second aspect, the calculating unit, configured to determine the second distance between the j th receiving antenna and the target according to the first distance, includes: determining the second distance between the j th receiving antenna and the target according to the first distance and a fifth distance between the reference receiving antenna and the j th receiving antenna.

[0039] With reference to the second aspect, in some implementations of the second aspect, the N receiving antennas are arranged at equal intervals.

[0040] With reference to the second aspect, in some implementations of the second aspect, the phase difference satisfies the following formula:

[0041]

[0042] wherein, is the phase difference of the first virtual receiving antenna and the second virtual receiving antenna, λ is the working wavelength of the antenna array of the MIMO radar, R1 is the first distance, R j is the second distance, L1 is the fourth distance, L i is the third distance.

[0043] With reference to the second aspect, in some implementations of the second aspect, the phase difference satisfies the following formula:

[0044]

[0045] wherein, is a phase difference of the first virtual receiving antenna and the second virtual receiving antenna, λ is a working wavelength of an antenna array of the MIMO radar, r1 is a measured value of the first distance, θ is an angle of arrival of the first virtual receiving antenna, d is a half wavelength of the MIMO radar antenna array, the kth virtual receiving antenna is the second virtual receiving antenna, and k is a positive integer less than or equal to MN.

[0046] With reference to the second aspect, in some implementations of the second aspect, the calculation unit is further configured to perform accurate estimation according to the phase difference, the phase difference satisfying the following formula:

[0047]

[0048] wherein d q is a distance between the qth virtual receiving antenna and the q-1th virtual receiving antenna when the angle of arrival is θ.

[0049] With reference to the second aspect, in some implementations of the second aspect, the calculation unit is further configured to determine a phase calibration coefficient of antenna array calibration of the MIMO radar according to the phase difference and a measured value of the phase difference before calibration.

[0050] The third aspect provides a computer storage medium, the computer storage medium storing computer executable instructions, the computer executable instructions being configured to cause a computer to perform any of the methods in the first aspect when the computer executable instructions are invoked by the computer.

[0051] The fourth aspect provides a radar, comprising: M transmitting antennas, the M transmitting antennas being configured to transmit signals, M being a positive integer; N receiving antennas, the N receiving antennas being configured to receive signals, N being a positive integer; and a processing unit, the processing unit being configured to perform any of the methods in the first aspect.

[0052] The fifth aspect provides a computing device, comprising: a memory configured to store a computer program, and a processor configured to invoke the computer program from the memory, the computer program being configured to cause the computing device to perform any of the methods in the first aspect when the computer program is executed.

[0053] The sixth aspect provides a vehicle-mounted system, comprising: M transmitting antennas, the M transmitting antennas being configured to transmit signals, M being a positive integer; N receiving antennas, the N receiving antennas being configured to receive signals, N being a positive integer; and any of the apparatuses in the second aspect. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 is a structural schematic diagram of an autonomous vehicle provided by an embodiment of the present application.

[0055] Figure 2 is a scenario diagram applicable to embodiments of the present application.

[0056] Figure 3 is a diagram of an antenna array of a MIMO radar applicable to embodiments of the present application.

[0057] Figure 4 is a diagram of a method of angle of arrival estimation provided by embodiments of the present application.

[0058] Figure 5 is a diagram of a method of angle of arrival estimation based on wave path difference provided by embodiments of the present application.

[0059] Figure 6 is a diagram of a result of angle of arrival estimation provided by embodiments of the present application.

[0060] Figure 7 is a diagram of a virtual receiving antenna provided by embodiments of the present application.

[0061] Figure 8 is a diagram of an apparatus for angle of arrival estimation provided by embodiments of the present application. DETAILED DESCRIPTION

[0062] Figure 1 is a functional block diagram of a vehicle 100 provided by embodiments of the present application. In one embodiment, the vehicle 100 is configured in a fully or partially autonomous driving mode. For example, the vehicle 100 can control itself while in the autonomous driving mode and can determine a current state of the vehicle and its surrounding environment, determine a possible behavior of at least one other vehicle in the surrounding environment, and determine a confidence level corresponding to a likelihood that the other vehicle will perform the possible behavior, by human operation, and control the vehicle 100 based on the determined information. While the vehicle 100 is in the autonomous driving mode, the vehicle 100 can be placed to operate without human interaction.

[0063] The vehicle 100 can include various subsystems, such as a travel system 102, a sensor system 104, a control system 106, one or more peripheral devices 108, and a power source 110, a computer system 112, and a user interface 116. Optionally, the vehicle 100 can include more or fewer subsystems, and each subsystem can include multiple elements. In addition, each subsystem and element of the vehicle 100 can be interconnected by wire or wirelessly.

[0064] The propulsion system 102 can include components that provide powered motion for the vehicle 100. In one embodiment, the propulsion system 102 can include an engine 118, an energy source 119, a drivetrain 120, and wheels / tires 121. The engine 118 can be a combustion engine, an electric motor, an air compression engine, or other types of engine combinations, such as a hybrid engine composed of a gas engine and an electric motor, a hybrid engine composed of a combustion engine and an air compression engine. The engine 118 converts the energy source 119 into mechanical energy.

[0065] Examples of the energy source 119 include gasoline, diesel, other petroleum-based fuels, propane, other compressed gas-based fuels, ethanol, solar panels, batteries, and other sources of electrical power. The energy source 119 can also provide energy for other systems of the vehicle 100.

[0066] The drivetrain 120 can transmit mechanical power from the engine 118 to the wheels 121. The drivetrain 120 can include a transmission, a differential, and drive axles. In one embodiment, the drivetrain 120 can also include other devices, such as a clutch. The drive axles can include one or more shafts that can be coupled to one or more wheels 121.

[0067] The sensor system 104 can include several sensors that sense information about the environment surrounding the vehicle 100. For example, the sensor system 104 can include a positioning system 122 (which can be a GPS system, a Beidou system, or other positioning system), an inertial measurement unit (IMU) 124, a radar 126, a laser rangefinder 128, and a camera 130. The sensor system 104 can also include sensors that monitor internal systems of the vehicle 100 (e.g., an in-vehicle air quality monitor, a fuel gauge, an oil temperature gauge, etc.). Sensor data from one or more of these sensors can be used to detect objects and their respective characteristics (location, shape, orientation, velocity, etc.). Such detection and identification are key functions for the safe operation of the autonomous vehicle 100.

[0068] The positioning system 122 can be used to estimate the geographic location of the vehicle 100. The IMU 124 is used to sense changes in position and orientation of the vehicle 100 based on inertial acceleration. In one embodiment, the IMU 124 can be a combination of an accelerometer and a gyroscope.

[0069] The radar 126 can utilize electromagnetic wave signals to sense objects within the surrounding environment of the vehicle 100. In some embodiments, in addition to sensing objects, the radar 126 can also be used to sense the velocity and / or heading of the objects.

[0070] The laser range finder 128 can utilize laser light to sense objects in the environment in which the vehicle 100 is located. In some embodiments, the laser range finder 128 can include one or more laser sources, a laser scanner, and one or more detectors, among other system components.

[0071] The camera 130 can be used to capture a plurality of images of the surrounding environment of the vehicle 100. The camera 130 can be a still camera or a video camera.

[0072] The control system 106 controls the operation of the vehicle 100 and its components. The control system 106 can include various elements, including a steering system 132, a throttle 134, a braking unit 136, a sensor fusion algorithm 138, a computer vision system 140, a route control system 142, and an obstacle avoidance system 144.

[0073] The steering system 132 is operable to adjust the heading direction of the vehicle 100. In one embodiment, the steering system 132 can be a steering wheel system.

[0074] The throttle 134 is used to control the operational speed of the engine 118 and, in turn, the speed of the vehicle 100.

[0075] The braking unit 136 is used to control the deceleration of the vehicle 100. The braking unit 136 can use friction to slow the wheels 121. In other embodiments, the braking unit 136 can convert the kinetic energy of the wheels 121 into an electrical current. The braking unit 136 can also take other forms to slow the rotational speed of the wheels 121 to control the speed of the vehicle 100.

[0076] The computer vision system 140 can be operable to process and analyze images captured by the camera 130 to identify objects and / or features in the surrounding environment of the vehicle 100. The objects and / or features can include traffic signals, road boundaries, and obstacles. The computer vision system 140 can use object recognition algorithms, Structure from Motion (SFM) algorithms, video tracking, and other computer vision techniques. In some embodiments, the computer vision system 140 can be used to map the environment, track objects, estimate the speed of objects, and the like.

[0077] The route control system 142 is used to determine the travel route of the vehicle 100. In some embodiments, the route control system 142 can combine data from the sensors 138, the GPS 122, and one or more predetermined maps to determine the travel route for the vehicle 100.

[0078] The obstacle avoidance system 144 is used to identify, evaluate, and avoid or otherwise navigate around potential obstacles in the environment of the vehicle 100.

[0079] Of course, in one example, the control system 106 can include, in addition to or instead of those shown and described, components other than those shown and described. Or some of the above-described components can be reduced.

[0080] The vehicle 100 interacts with external sensors, other vehicles, other computer systems, or users through the peripherals 108. The peripherals 108 can include a wireless communication system 146, an on-board computer 148, a microphone 150, and / or a speaker 152.

[0081] In some embodiments, the peripherals 108 provide a means for a user of the vehicle 100 to interact with the user interface 116. For example, the on-board computer 148 can provide information to a user of the vehicle 100. The user interface 116 can also operate the on-board computer 148 to receive input from the user. The on-board computer 148 can be operated through a touch screen. In other cases, the peripherals 108 can provide a means for the vehicle 100 to communicate with other devices located within the vehicle. For example, the microphone 150 can receive audio (e.g., voice commands or other audio input) from a user of the vehicle 100. Similarly, the speaker 152 can output audio to a user of the vehicle 100.

[0082] The wireless communication system 146 can wirelessly communicate with one or more devices, either directly or via a communication network. For example, the wireless communication system 146 can use 3G cellular communication, such as CDMA, EVDO, GSM / GPRS, or 4G cellular communication, such as LTE. Or 5G cellular communication. The wireless communication system 146 can utilize WiFi for communication with a wireless local area network (WLAN). In some embodiments, the wireless communication system 146 can utilize an infrared link, Bluetooth, or ZigBee for direct communication with a device. Other wireless protocols, such as various vehicle communication systems, for example, the wireless communication system 146 can include one or more dedicated short range communications (DSRC) devices, which can include public and / or private data communication between vehicles and / or roadside stations.

[0083] The power source 110 can provide power to various components of the vehicle 100. In one embodiment, the power source 110 can be a rechargeable lithium-ion or lead-acid battery. One or more battery packs of such a battery can be configured as the power source to provide power to various components of the vehicle 100. In some embodiments, the power source 110 and the energy source 119 can be implemented together, such as in some all-electric vehicles.

[0084] Some or all of the functionality of the vehicle 100 is controlled by a computer system 112. The computer system 112 can include at least one processor 113 that executes instructions 115 stored in a non-transitory computer readable medium, such as a memory 114. The computer system 112 can also be a plurality of computing devices that control individual components or subsystems of the vehicle 100 in a distributed manner.

[0085] The processor 113 can be any conventional processor, such as a commercially available CPU. Alternatively, the processor can be a special purpose device such as an ASIC or other hardware-based processor. Although Figure 1 Although the processor, memory, and other elements of the computer 110 are functionally illustrated as being in the same block, it should be understood by those of ordinary skill in the art that the processor, computer, or memory can actually include multiple processors, computers, or memories that can or can not be stored in the same physical housing. For example, the memory can be a hard drive or other storage medium located in a different housing than the computer 110. Thus, references to the processor or computer will be understood to include references to a collection of processors or computers or memories that can or can not operate in parallel. Rather than using a single processor to perform the steps described herein, some components, such as the steering assembly and the deceleration assembly, can each have their own processor that only performs calculations related to the functionality specific to the component.

[0086] In various aspects described herein, the processor can be located remotely from the vehicle and in wireless communication with the vehicle. In other aspects, some of the processes described herein are performed on a processor disposed within the vehicle while others are performed by a remote processor, including taking the necessary steps to perform a single maneuver.

[0087] In some embodiments, the memory 114 can contain instructions 115 (e.g., program logic) that can be executed by the processor 113 to perform various functions of the vehicle 100, including those described above. The memory 114 can also contain additional instructions, including instructions to send data to, receive data from, interact with, and / or control one or more of the propulsion system 102, the sensor system 104, the control system 106, and the peripherals 108.

[0088] In addition to the instructions 115, the memory 114 can also store data, such as road maps, route information, the location, orientation, speed, and other such vehicle data of the vehicle, as well as other information. Such information can be used by the vehicle 100 and the computer system 112 during operation of the vehicle 100 in autonomous, semi-autonomous, and / or manual modes.

[0089] Entry: can insert and actual invention related description: such as if the actual invention point to adjust the speed, then here describes how speed adjustment, if the lane control, then here describes how lane control, need which data, according to these data how lane control and so on.

[0090] User interface 116 for providing information to or receiving information from a user of vehicle 100. Optionally, user interface 116 can include one or more input / output devices within the set of peripheral devices 108, such as wireless communication system 146, on-board computer 148, microphone 150, and speaker 152.

[0091] Computer system 112 can control the functions of vehicle 100 based on inputs received from various subsystems (e.g., travel system 102, sensor system 104, and control system 106), as well as from user interface 116. For example, computer system 112 can utilize inputs from control system 106 in order to control steering unit 132 to avoid obstacles detected by sensor system 104 and obstacle avoidance system 144. In some embodiments, computer system 112 can be operable to provide control over many aspects of vehicle 100 and its subsystems.

[0092] Optionally, one or more of the above-described components can be installed separately from or associated with vehicle 100. For example, memory 114 can exist partially or entirely separately from vehicle 100. The above-described components can be communicatively coupled together in a wired and / or wireless manner.

[0093] Optionally, the above-described components are just an example, in actual application, components in each module above can be added or deleted according to actual needs, Figure 1 It should not be understood as a limitation to the embodiments of the present application.

[0094] An autonomous vehicle traveling on a roadway, such as vehicle 100 above, can identify objects within its surrounding environment in order to determine an adjustment to a current speed. The objects can be other vehicles, traffic control devices, or other types of objects. In some examples, each identified object can be considered independently, and based on respective characteristics of the object, such as its current speed, acceleration, spacing from the vehicle, etc., can be used to determine a speed at which the autonomous vehicle is to adjust.

[0095] Optionally, the autonomous vehicle vehicle 100 or a computing device associated with autonomous vehicle 100 (such as computer system 112) can be configured to identify objects in the surrounding environment of the vehicle and to determine a speed at which the vehicle is to adjust based on the identified objects. Figure 1The computer system 112, computer vision system 140, and memory 114 can predict the behavior of the identified objects based on the characteristics of the identified objects and the state of the surrounding environment (e.g., traffic, rain, ice on the road, etc.). Optionally, each identified object depends on the behavior of each other, so all identified objects can also be considered together to predict the behavior of a single identified object. The vehicle 100 can adjust its speed based on the predicted behavior of the identified objects. In other words, the autonomous vehicle can determine what steady state the vehicle will need to adjust to (e.g., accelerate, decelerate, or stop) based on the predicted behavior of the objects. In this process, other factors can also be considered in determining the speed of the vehicle 100, such as the lateral position of the vehicle 100 in the road, the curvature of the road, the proximity of static and dynamic objects, etc.

[0096] In addition to providing instructions to adjust the speed of the autonomous vehicle, the computing device can also provide instructions to modify the steering angle of the vehicle 100 so that the autonomous vehicle follows a given trajectory and / or maintains a safe lateral and longitudinal distance from objects near the autonomous vehicle (e.g., cars in adjacent lanes on the road).

[0097] The aforementioned vehicle 100 can be a car, truck, motorcycle, bus, ship, airplane, helicopter, lawnmower, recreational vehicle, amusement park vehicle, construction equipment, tram, golf cart, train, and handcart, etc., and this application embodiment does not impose any special limitations.

[0098] Figure 2 This is a schematic diagram of a scenario applicable to the embodiments of this application.

[0099] It should be understood that in far-field virtual MIMO radar, based on the assumption that the wavefront of the received electromagnetic wave is a plane wave, the wavefront refers to the surface formed by particles that have just begun to displace at a certain moment when the electromagnetic wave radiated by the radar propagates in the medium.

[0100] like Figure 2 As shown, the spacing between transmit (TX) antennas can be equivalently converted into virtual receive (RX) antennas, thus forming a virtual single-input multiple-output (SIMO) radar with one TX and multiple virtual RX antennas. However, in near-field AOA estimation, the spacing between TX antennas cannot be directly converted into virtual RX antennas. The distances between each transmit antenna and the target, each receive antenna and the target, and then the distances between each transmit antenna and each receive antenna must be calculated separately. Here, a virtual receive antenna refers to the receiving antenna that receives the signal corresponding to the signal transmitted by each of the multiple transmit antennas in the MIMO radar's antenna array.

[0101] This application provides a method for estimating the angle of arrival (AOA). Unlike traditional methods, the near-field estimation method in this application takes into account the actual physical locations of multiple transmitting antennas. It should be understood that the technical solution of this application can be applied to transmitting antennas with uniform spacing dt and receiving antennas with uniform spacing dr, or to non-uniformly distributed transmitting and receiving antennas. It calculates the path difference between the virtual receiving antenna composed of each transmitting and receiving antenna and the first virtual receiving antenna, thereby estimating the AOA.

[0102] Figure 3 This is a schematic diagram of an antenna array for a MIMO radar applicable to embodiments of this application. Figure 1 The radar 126 shown in this application uses a uniformly distributed TX antenna and RX antenna as an example, but it can also be applied to non-uniformly distributed TX antennas and RX antennas. This application does not impose any limitations.

[0103] Assume the MIMO radar's antenna array has N receiving antennas (N is a positive integer, and adjacent receiving antennas are evenly spaced by d). r ), and M transmitting antennas (M is a positive integer, and when M is greater than 1, the uniform spacing is d). t This allows the synthesis of M×N virtual receiving antennas. The distance between the i-th transmitting antenna and the target is L. i Where i = 1, 2, ..., M, and the distance between the j-th receiving antenna and the target is R. j , where j = 1, 2, ..., N.

[0104] Assume the number of receiving antennas N is 10 and the number of transmitting antennas M is 3. For example... Figure 3 The diagram illustrates signal propagation with 3 transmitting antennas and 10 receiving antennas. The diagram assumes that the first transmitting antenna and the first receiving antenna have the same horizontal position, but in reality they may differ; this application does not impose such a limitation.

[0105] Figure 4 This is a schematic diagram of an angle of arrival estimation method provided in an embodiment of this application.

[0106] 110, Measure the distance between the reference receiving antenna and the target.

[0107] It should be understood that, such as Figure 3As shown, 30 virtual receiving antennas are determined by 3 transmitting antennas and 10 receiving antennas, the first virtual receiving antenna is one of the 30 virtual receiving antennas, and the first virtual receiving antenna is determined by a reference transmitting antenna and a reference receiving antenna. Among them, the reference transmitting antenna and the reference receiving antenna can be arbitrarily selected. In order to facilitate signal processing, the leftmost or rightmost antenna of the antenna array can be selected as the reference transmitting antenna and the reference receiving antenna.

[0108] Optionally, the first distance R1 between the reference receiving antenna and the target can be measured in a darkroom.

[0109] Optionally, the fourth distance L1 between the reference transmitting antenna and the target can be obtained through the physical geometric relationship of the first transmitting antenna and the first receiving antenna, wherein the first transmitting antenna can be the first transmitting antenna from left to right in the M transmitting antennas. In general, the horizontal distance interval of the first transmitting antenna and the first receiving antenna in the antenna array of the MIMO radar is considered to be very small, so L1≈R1=r1, wherein r1 is the distance value between the reference receiving antenna and the target obtained by measurement, that is, a specific numerical value.

[0110] 120, determining the second distance Rj between the jth receiving antenna and the target according to the first distance R1 between the reference receiving antenna and the target j .

[0111] Optionally, the second distance Rj between the jth receiving antenna and the target can be determined according to the first distance R1 between the reference receiving antenna and the target and the fifth distance between the reference receiving antenna and the jth receiving antenna corresponding to the second virtual receiving antenna j .

[0112] Optionally, when the receiving antennas are arranged at equal intervals, the second distance Rj between the jth receiving antenna and the target can be determined according to the first distance R1 between the reference receiving antenna and the target and the interval d between the receiving antennas r , so as to obtain the second distance Rj between the jth receiving antenna and the target j . It should be understood that when the receiving antennas are arranged unevenly, the second distance Rj between the jth receiving antenna and the target can be determined according to the horizontal distance between the jth receiving antenna and the reference receiving antenna, that is, the fifth distance j .

[0113] Optionally, the third distance Li between the ith transmitting antenna and the target can be determined according to the fourth distance L1 between the reference transmitting antenna and the target and the sixth distance between the reference transmitting antenna and the ith transmitting antenna corresponding to the second virtual receiving antenna i .

[0114] Optionally, when the respective transmitting antennas are arranged at equal intervals, the third distance L between the ith transmitting antenna and the target can be determined according to a fourth distance L1 between the reference transmitting antenna and the target and the known interval d between the transmitting antennas t , as shown in Fig. 1. i It should be understood that when the transmitting antennas are arranged unevenly, the third distance L between the ith transmitting antenna and the target can be determined according to a sixth distance between the ith transmitting antenna and the reference transmitting antenna, i.e., the horizontal distance between the ith transmitting antenna and the reference transmitting antenna i . As shown in Fig. 1, x and y can be expressed by geometric relations as follows: Figure 3

[0115] x = r1cosθ;

[0116] y = r1sinθ;

[0117] The second distance R between the jth receiving antenna and the target and the third distance L between the ith transmitting antenna and the target are respectively expressed as: j i

[0118]

[0119]

[0120] wherein θ is the angle of arrival of the first virtual receiving antenna, and is an unknown quantity to be estimated.

[0121] 130, determining the path difference between the first virtual receiving antenna and the second virtual receiving antenna according to the path of the first virtual receiving antenna and the path of the second virtual receiving antenna.

[0122] wherein the first virtual receiving antenna is determined by the reference transmitting antenna and the reference receiving antenna, and the second virtual receiving antenna is determined by the ith transmitting antenna and the jth receiving antenna, and the path difference between the first virtual receiving antenna and the second virtual receiving antenna can be determined according to a first distance R1 between the reference receiving antenna and the target and a second distance R j between the jth receiving antenna and the target.

[0123] It should be understood that for the first virtual receiving antenna determined by the reference transmitting antenna and the reference receiving antenna, the corresponding first path is the distance traveled by the electromagnetic wave emitted by the reference transmitting antenna after being reflected by the target to reach the reference receiving antenna. For the second virtual receiving antenna determined by the ith transmitting antenna and the jth receiving antenna, the corresponding second path is the distance traveled by the electromagnetic wave emitted by the ith transmitting antenna after being reflected by the target to reach the jth receiving antenna.

[0124] ​​​Optionally, the first wave path can be determined by a first distance R1 between the reference receiving antenna and the target and a fourth distance L1 between the reference transmitting antenna and the target. The second wave path can be determined by a second distance Rj between the jth receiving antenna and the target and a third distance Li between the ith transmitting antenna and the target. j i .

[0125] According to the distance between the ith transmitting antenna and the jth receiving antenna, i.e. (L i +R j ), the wave path difference of the second wave path of the second virtual receiving antenna relative to the first wave path of the first virtual receiving antenna, i.e. (L i +R j )-(L1+R1), can be calculated.

[0126] For example, in the Figure 3 , the second wave path of the second virtual receiving antenna formed by the 2nd transmitting antenna and the 5th receiving antenna is L2+R5, where the third distance L2 between the 2nd transmitting antenna and the target can be equal to r2, the second distance R5 between the 5th receiving antenna and the target can be equal to r3, r2 is the distance value between the 2nd transmitting antenna and the target calculated, r3 is the distance value between the 3rd receiving antenna and the target calculated, and the wave path difference relative to the first virtual receiving antenna formed by the reference transmitting antenna and the reference receiving antenna is r2+r3-2xr1, i.e.

[0127]

[0128] 140, the angle of arrival is determined according to the wave path difference between the first virtual receiving antenna and the second virtual receiving antenna.

[0129] The angle of arrival of the first virtual receiving antenna can be determined according to the wave path difference between the second virtual receiving antenna and the first virtual receiving antenna determined by the ith transmitting antenna and the jth receiving antenna.

[0130] It should be understood that when L1=R1=r1, the 1st transmitting antenna and the 1st receiving antenna can be considered to be located close to each other, i.e. the reference transmitting antenna and the reference receiving antenna are close to each other, and the first virtual receiving antenna is the 1st receiving antenna.

[0131] Optionally, when the angle of arrival is defined as the included angle between the center point (normal line) of the receiving antenna array and the target, the angle of arrival can be converted from θ in Figure 3 according to the known geometric relationship. As Figure 3 ​As shown, the angle of arrival θ of the first virtual receiving antenna has been obtained, and the distance value r1 between the reference receiving antenna and the target is measured, and the distance between the array center point O and the first receiving antenna is known as D / 2, where D is the length of the antenna array of the MIMO radar, the angle θ1 between the target and the receiving antenna array is obtained according to the cosine theorem, and finally the angle of arrival of the center point of the receiving antenna array is obtained

[0132] Figure 5 is a schematic diagram of a method for estimating the angle of arrival according to the path difference provided by the embodiments of the present application.

[0133] 210, determining the phase difference between the first virtual receiving antenna and the second virtual receiving antenna according to the path difference between the first virtual receiving antenna and the second virtual receiving antenna.

[0134] The phase difference of the signal received by the second virtual receiving antenna corresponding to the signal transmitted by the ith transmitting antenna and received by the jth receiving antenna, compared with the signal transmitted by the reference receiving antenna and received by the reference receiving antenna, i.e. the signal received by the first virtual receiving antenna, can be expressed as:

[0135]

[0136] wherein, is the phase difference between the first virtual receiving antenna and the second virtual receiving antenna, λ is the working wavelength of the millimeter wave radar, R1 is the first distance between the reference receiving antenna and the target, L1 is the fourth distance between the reference transmitting antenna and the target, R j is the second distance between the jth receiving antenna and the target, L i is the third distance between the ith transmitting antenna and the target.

[0137] 220, constructing a steering vector according to the phase difference between the first virtual receiving antenna and the second virtual receiving antenna.

[0138] According to the phase difference constructing a steering vector a(θ), wherein the element unit of the steering vector is

[0139] That is, the steering vector can be expressed as:

[0140]

[0141] 230, determining the angle of arrival according to the steering vector.

[0142] wherein the angle of arrival θ of the first virtual receiving antenna can be estimated according to the steering vector a(θ).

[0143] Alternatively, algorithms such as digital beamforming (DBF), minimum variance distortionless response (MVDR), or multiple signal classification (MUSIC) can be used. For example, for estimating the angle of arrival using the DBF algorithm, the angle spectrum can be expressed as:

[0144] S=a(θ) H x*x H a(θ);

[0145] Where x represents the received signal vector input to the DBF algorithm, a(θ) represents the steering vector constructed in step 220, and H represents the conjugate transpose. Substituting the constructed a(θ) into the above equation, by searching for angles, i.e. enumerating the angle values ​​of the angle of arrival, the target angle of arrival can be estimated when the value in the angle spectrum is the maximum or a local maximum.

[0146] Figure 6 This is a schematic diagram of the angle of arrival estimation results provided in the embodiments of this application.

[0147] like Figure 6 As shown, the virtual receiving antenna formed in the radar can be a large array including 256 virtual receiving antenna elements. After near-field estimation, the angle of arrival of the first virtual receiving antenna in the near field can still be accurately estimated. Figure 6 As shown, the virtual receiving antenna array contains 256 virtual elements. Using the DBF angle estimation algorithm and a signal-to-noise ratio (SNR) of 15 dB, the amplitude is 7.098e when the angle of arrival is 45°, according to the technical solution provided in this application embodiment. -16 , which is the maximum amplitude in the angular spectrum, that is, the arrival angle of 45° is accurately estimated, and there will be no problem of angular spectrum dispersion.

[0148] This application also provides a simpler method for angle of arrival estimation, which no longer calculates the distance between the transmitting antenna and the target, but instead uses the spacing of the virtual receiving antenna array as a variable (no longer as a constant) for angle of arrival estimation.

[0149] Figure 7 This is a schematic diagram of a virtual receiving antenna provided in an embodiment of this application.

[0150] like Figure 7As shown, MxN virtual receiving antennas are determined by M transmitting antennas and N receiving antennas, where θ is an angle of arrival, which can be an angle between the 1st receiving antenna and the target, the 1st receiving antenna is selected as a reference receiving antenna, at this time, the 1st receiving antenna can be the 1st receiving antenna from right to left in the receiving antenna array.

[0151] Similarly to the method shown in Figure 4 The step 140 can be replaced by the following method:

[0152] A first distance R1 between the reference receiving antenna (the 1st virtual receiving antenna) and the target, where R1=r1, r1 is a distance value between the reference receiving antenna and the target obtained by measurement, i.e. a specific numerical value. Assuming that the transmitting antennas of all virtual receiving antennas are the same transmitting antenna, at this time, since the distances between the transmitting antennas forming all virtual receiving antennas and the target are all equal, the path difference between the 2nd virtual receiving antenna and the 1st virtual receiving antenna will not change due to the different positions of the transmitting antennas determining the virtual receiving antennas, i.e. the path difference between the 1st virtual receiving antenna and the 2nd virtual receiving antenna can be determined according to the first distance R1 between the reference receiving antenna and the target. At this time, the 2nd virtual receiving antenna is the kth virtual receiving antenna, and the path difference with the 1st virtual receiving antenna is:

[0153]

[0154] Where R k is the distance between the 2nd virtual receiving antenna and the target, assuming that the virtual receiving antennas are arranged at equal intervals at this time, d is the interval between adjacent elements in the virtual receiving antenna array.

[0155] In the far field case, the interval d between adjacent elements in the virtual receiving antenna array is a constant related to the working wavelength, which can be half of the wavelength corresponding to the center frequency of the radar working; in the near field case, the interval d between adjacent elements in the virtual receiving antenna array is a variable related to the angle of arrival of the 1st virtual receiving antenna.

[0156] Alternatively, the path difference shown in the embodiment can be brought into the method of estimating the angle of arrival shown in Figure 5 The phase difference is:

[0157]

[0158] Where λ is the working wavelength of the millimeter wave radar, r1 is the distance value between the reference receiving antenna and the target, θ is the angle of arrival of the 1st virtual receiving antenna, d is half the wavelength of the millimeter wave radar, the kth virtual receiving antenna is the 2nd virtual receiving antenna, and k is a positive integer less than or equal to MxN.

[0159] The guiding vector constructed according to the above formula can achieve better estimation performance in near-field angle of arrival estimation when the antenna array is small.

[0160] With the increase of the aperture of the antenna array of the MIMO radar, under the condition of the near field, for the formula:

[0161]

[0162] wherein the interval d between adjacent elements in the virtual receiving antenna array is no longer half a wavelength, but a variable, which can be replaced by (k-1)d in the above formula, and the phase difference can be represented as:

[0163]

[0164] wherein d q (θ) represents the distance between the qth virtual receiving antenna and the q-1th virtual receiving antenna when the angle of arrival of the first virtual receiving antenna is θ.

[0165] From the above formula, it can be seen that d q (θ) is related to the position of the target, that is, related to the first distance between the reference receiving antenna and the target.

[0166] Therefore, through simulation and / or actual measurement of the method as shown in Figure 4 , the relationship between d q (θ), θ, and r1 can be established, that is, the corresponding relationship table of {d q (θ), θ, and r1} is established in advance, and the angle of arrival can be accurately estimated by this method.

[0167] For example, the relationship between d q (θ), θ, and r1 can be as shown in Table 1, and when the DBF angle estimation algorithm is used to estimate the angle of arrival, the corresponding values in Table 1 can be brought in when the angle value of the angle of arrival is enumerated, and then the maximum value or local maximum value in the angle spectrum is obtained, so as to accurately estimate the angle of arrival.

[0168] Table 1

[0169]

[0170] wherein x1 to x 12 represent the spacing of the 1st, 2nd, and 3rd virtual receiving antennas compared with the 0th, 1st, and 2nd virtual receiving antennas when θ and r1 are determined.

[0171] Optionally, the related data in Table 1 can be stored in the memory 114 as shown in Figure 1 .

[0172] ​Suppose the aperture of the virtual receiving antenna is D, and the wavelength of the working frequency band is λ. Since the commonly used judging formula for the near field is: D 2 / λ = 64.1 m (suppose D = 0.5, λ = 0.0039 m), thus the near field condition is generally applicable in the common microwave darkroom.

[0173] The construction method of the path difference / guiding vector in the embodiments of the present application can also be applied to antenna array calibration. According to the above phase difference and the measured value of the phase difference before calibration, the phase calibration coefficient of the antenna array calibration of the MIMO radar is determined. The phase calibration coefficient of the kth receiving antenna satisfies the following formula:

[0174]

[0175] wherein, is the theoretical value, i.e., the phase difference in the above embodiments or is the measured value of the phase difference before calibration.

[0176] It should be understood that the phase calibration coefficient obtained by using the theoretical path difference / phase difference of the embodiments of the present application for calculation is more accurate, and thus a more accurate angle of arrival estimation result can be obtained.

[0177] The near field calibration parameter obtained in the embodiments of the present application can also be extended to a far field calibration parameter. For the same radar, the far field calibration result can be calculated according to the near field calibration result.

[0178] Optionally, the near field angle of arrival calibration method described above can be directly used for far field calibration. The reasons are as follows: is the observation phase in the near field calibration, wherein, is the real antenna phase of the kth antenna without antenna disturbance under the near field condition, x k represents the phase disturbance of the kth antenna and its radio frequency channel; is the observation phase in the far field calibration, wherein, is the real antenna phase of the kth antenna without antenna disturbance under the far field condition, y k represents the phase disturbance of the kth antenna and its radio frequency channel, and the following formula is obtained:

[0179]

[0180]

[0181] After the radar calibration in the near field, in some scenarios, thus x k =yk .

[0182] Figure 8 is a schematic diagram of an apparatus for angle of arrival estimation provided by an embodiment of the present application, which can be located in a MIMO radar, and used for measuring an angle of arrival to a target.

[0183] As shown in Figure 8 , the apparatus for angle of arrival estimation can include a measuring unit 310 and a calculating unit 320.

[0184] The measuring unit 310 can be configured to measure a first distance between a reference receiving antenna and the target, the reference receiving antenna being one of N receiving antennas. The calculating unit 320 can be configured to determine a second distance between a jth receiving antenna and the target according to the first distance, where j is a positive integer less than or equal to N. The calculating unit 320 can be further configured to determine a path difference of a first virtual receiving antenna and a second virtual receiving antenna according to the first distance and the second distance, the reference transmitting antenna being one of M transmitting antennas. The first virtual receiving antenna is determined by the reference transmitting antenna and the reference receiving antenna, and the second virtual receiving antenna is determined by an ith transmitting antenna and the jth receiving antenna, i being a positive integer less than or equal to M. The calculating unit 320 can be further configured to determine an angle of arrival of the first virtual receiving antenna according to the path difference.

[0185] Optionally, the calculating unit 320 can be further configured to determine the path difference of the first virtual receiving antenna and the second virtual receiving antenna according to the first distance and the second distance, including: determining a first path of the first virtual receiving antenna; determining a second path of the second virtual receiving antenna; and determining the path difference of the first virtual receiving antenna and the second virtual receiving antenna according to the first path and the second path. The determination of the second path of the second virtual receiving antenna can include: determining a third distance between the ith transmitting antenna and the target according to the first distance; and determining the second path of the second virtual receiving antenna according to the second distance and the third distance.

[0186] Optionally, the determination of the first path of the first virtual receiving antenna includes: determining a fourth distance between the reference transmitting antenna and the target according to the first distance; and determining the first path of the first virtual receiving antenna according to the first distance and the fourth distance.

[0187] Optionally, the calculating unit 320 can be configured to determine the second distance between the jth receiving antenna and the target according to the first distance, including: determining the second distance between the jth receiving antenna and the target according to the first distance and a fifth distance between the reference receiving antenna and the jth receiving antenna.

[0188] Optionally, the N receiving antennas are arranged at equal intervals.

[0189] Optionally, the computing unit 320 is further configured to determine the angle of arrival of the first virtual receiving antenna according to the wave path difference, including: determining a phase difference of the first virtual receiving antenna and the second virtual receiving antenna according to the wave path difference; constructing a steering vector according to the phase difference; and determining the angle of arrival of the first virtual receiving antenna according to the steering vector.

[0190] Optionally, the phase difference satisfies the following formula:

[0191]

[0192] wherein, is the phase difference of the first virtual receiving antenna and the second virtual receiving antenna, λ is the working wavelength of the antenna array of the MIMO radar, R1 is the first distance, R j is the second distance, L1 is the fourth distance, L i is the third distance.

[0193] Optionally, the phase difference satisfies the following formula:

[0194]

[0195] wherein, is the phase difference of the first virtual receiving antenna and the second virtual receiving antenna, λ is the working wavelength of the antenna array of the MIMO radar, r1 is the measured value of the first distance, θ is the angle of arrival of the first virtual receiving antenna, d is the half wavelength of the antenna array of the MIMO radar, the kth virtual receiving antenna is the second virtual receiving antenna, and k is a positive integer less than or equal to MN.

[0196] Optionally, the phase difference satisfies the following formula:

[0197]

[0198] wherein, d q (θ) is the distance between the qth virtual receiving antenna and the q-1th virtual receiving antenna when the angle of arrival is θ.

[0199] Optionally, the computing unit 320 is further configured to determine a phase calibration coefficient of the antenna array calibration of the MIMO radar according to the phase difference and a measured value of the phase difference before calibration.

[0200] Embodiments of the present application further provide a device for angle of arrival estimation. The device can be a device for angle of arrival estimation, or a chip or circuit arranged in the device for angle of arrival estimation. For example, the device can be a router or a switch, or a chip in the router or the switch.

[0201] The apparatus includes a processor, a memory and a communication interface. The memory stores instructions, and the processor is configured to execute the instructions in the memory. When the instructions are executed, the processor is configured to execute the method provided in the method embodiments. The processor is further configured to control the communication interface to communicate with the outside world.

[0202] Further, the processor, the memory and the communication interface can communicate with each other through internal connection paths to transfer control and / or data signals.

[0203] Further, the memory can be integrated in the processor or arranged separately from the processor.

[0204] Specifically, the apparatus for estimating the angle of arrival can be used to execute each step of the method in Figure 3 and Figure 4 The apparatus can include modules for executing the method executed by the apparatus for estimating the angle of arrival in Figure 3 and Figure 4 Each module in the apparatus and the other operations and / or functions described above are respectively used to implement the corresponding processes in Figure 3 and Figure 4 The specific processes of each module for executing the corresponding steps are described in detail in the methods, and are not described here again for brevity.

[0205] The embodiments of the present application also provide a computer-readable storage medium including a computer program, which, when executed on a computer, causes the computer to execute the method provided in the method embodiments.

[0206] The embodiments of the present application also provide a computer program product including instructions, which, when executed on a computer, causes the computer to execute the method provided in the method embodiments.

[0207] The embodiments of the present application also provide a chip system including a memory and a processor. The memory is configured to store a computer program. The processor is configured to call and execute the computer program from the memory, so that a network device installed with the chip system executes the method provided in the method embodiments.

[0208] The chip system can include an input circuit or interface for sending information or data, and an output circuit or interface for receiving information or data.

[0209] It should be understood that, in the embodiments of the present application, the processor can be a central processing unit (CPU), and the processor can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0210] Those skilled in the art can clearly understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0211] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0212] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0213] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. According to actual needs, some or all of the units can be selected to achieve the purpose of the embodiment scheme.

[0214] In addition, each function unit in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit.

[0215] The functions, if implemented in the form of software function units and sold or used as independent products, can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application, essentially or in part, or parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, and various other media that can store program codes.

[0216] The above is merely specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which shall be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for angle of arrival estimation, applied to a multiple-input multiple-output (MIMO) radar, wherein the antenna array of the MIMO radar comprises M transmitting antennas and N equally spaced receiving antennas, where M is a positive integer and N is a positive integer, characterized in that... include: The first distance between the reference receiving antenna and the target is measured, wherein the reference receiving antenna is one of the N receiving antennas; A second distance between the j-th receiving antenna and the target is determined based on the first distance, where j is a positive integer less than or equal to N; The path difference between the first virtual receiving antenna and the second virtual receiving antenna is determined based on the first distance and the second distance, wherein the first virtual receiving antenna is determined by the reference transmitting antenna and the reference receiving antenna, the reference transmitting antenna being one of the M transmitting antennas, and the second virtual receiving antenna is determined by the i-th transmitting antenna and the j-th receiving antenna, where i is a positive integer less than or equal to M; The angle of arrival of the first virtual receiving antenna is determined based on the path difference.

2. The method according to claim 1, characterized in that, Determining the path difference between the first virtual receiving antenna and the second virtual receiving antenna based on the first distance and the second distance includes: Determine the first wavelength of the first virtual receiving antenna; Determine the second path of the second virtual receiving antenna; The path difference between the first virtual receiving antenna and the second virtual receiving antenna is determined based on the first path and the second path. Determining the second path of the second virtual receiving antenna includes: The third distance between the i-th transmitting antenna and the target is determined based on the first distance. The second path of the second virtual receiving antenna is determined based on the second distance and the third distance.

3. The method according to claim 2, characterized in that, Determining the first path of the first virtual receiving antenna includes: A fourth distance between the reference transmitting antenna and the target is determined based on the first distance. The first path of the first virtual receiving antenna is determined based on the first distance and the fourth distance.

4. The method according to any one of claims 1 to 3, characterized in that, Determining the second distance between the j-th receiving antenna and the target based on the first distance includes: The second distance between the j-th receiving antenna and the target is determined based on the first distance and the fifth distance between the reference receiving antenna and the j-th receiving antenna. The fifth distance is based on the interval d. r It is determined that the interval d r It is the spacing between adjacent receiving antennas.

5. The method according to claim 3, characterized in that, Determining the angle of arrival of the first virtual receiving antenna based on the path difference includes: The phase difference between the first virtual receiving antenna and the second virtual receiving antenna is determined based on the path difference; Construct a steering vector based on the phase difference; The angle of arrival of the first virtual receiving antenna is determined based on the steering vector.

6. The method according to claim 5, characterized in that, The phase difference satisfies the following formula: in, Let λ be the phase difference between the first virtual receiving antenna and the second virtual receiving antenna, λ be the operating wavelength of the antenna array of the MIMO radar, R1 be the first distance, and R j L1 is the second distance, and L2 is the fourth distance. i This refers to the third distance.

7. The method according to claim 1, characterized in that, Determining the angle of arrival of the first virtual receiving antenna based on the path difference includes: The phase difference between the first virtual receiving antenna and the second virtual receiving antenna is determined based on the path difference; Construct a steering vector based on the phase difference; The angle of arrival of the first virtual receiving antenna is determined based on the steering vector; The phase difference satisfies the following formula: in, Let λ be the phase difference between the first virtual receiving antenna and the second virtual receiving antenna, λ be the operating wavelength of the antenna array of the MIMO radar, r1 be the measured value of the first distance, θ be the angle of arrival of the first virtual receiving antenna, d be the half wavelength of the antenna array of the MIMO radar, the kth virtual receiving antenna is the second virtual receiving antenna, and k is a positive integer less than or equal to M×N.

8. The method according to claim 7, characterized in that, The method further includes: Based on the phase difference, an accurate estimate is made, and the phase difference satisfies the following formula: Where, d q (θ) is the distance between the q-th virtual receiving antenna and the (q-1)-th virtual receiving antenna when the angle of arrival is θ.

9. The method according to any one of claims 5 to 8, characterized in that, The method further includes: Based on the phase difference and the measured phase difference before calibration, the phase calibration coefficient for the antenna array calibration of the MIMO radar is determined.

10. An angle-of-arrival estimation apparatus, located in a MIMO radar, wherein the antenna array of the MIMO radar comprises M transmitting antennas and N equally spaced receiving antennas, where M is a positive integer and N is a positive integer, characterized in that... include: A measurement unit is used to measure a first distance between a reference receiving antenna and a target, wherein the reference receiving antenna is one of the N receiving antennas; A calculation unit is configured to determine a second distance between the j-th receiving antenna and the target based on the first distance, wherein j is a positive integer less than or equal to N; The calculation unit is also used to determine the path difference between the first virtual receiving antenna and the second virtual receiving antenna based on the first distance and the second distance. The reference transmitting antenna is one of the M transmitting antennas. The first virtual receiving antenna is determined by the reference transmitting antenna and the reference receiving antenna, and the second virtual receiving antenna is determined by the i-th transmitting antenna and the j-th receiving antenna, where i is a positive integer less than or equal to M. The calculation unit is also used to determine the angle of arrival of the first virtual receiving antenna based on the path difference.

11. The apparatus according to claim 10, characterized in that, The calculation unit is further configured to determine the path difference between the first virtual receiving antenna and the second virtual receiving antenna based on the first distance and the second distance, including: Determine the first wavelength of the first virtual receiving antenna; Determine the second path of the second virtual receiving antenna; The path difference between the first virtual receiving antenna and the second virtual receiving antenna is determined based on the first path and the second path. Determining the second path of the second virtual receiving antenna includes: The third distance between the i-th transmitting antenna and the target is determined based on the first distance. The second path of the second virtual receiving antenna is determined based on the second distance and the third distance.

12. The apparatus according to claim 11, characterized in that, Determining the first path of the first virtual receiving antenna includes: A fourth distance between the reference transmitting antenna and the target is determined based on the first distance. The first path of the first virtual receiving antenna is determined based on the first distance and the fourth distance.

13. The apparatus according to any one of claims 10 to 12, characterized in that, The calculation unit is configured to determine a second distance between the j-th receiving antenna and the target based on the first distance, including: The second distance between the j-th receiving antenna and the target is determined based on the first distance and the fifth distance between the reference receiving antenna and the j-th receiving antenna. The fifth distance is based on the interval d. r It is determined that the interval d r It is the spacing between adjacent receiving antennas.

14. The apparatus according to claim 12, characterized in that, The calculation unit is further configured to determine the angle of arrival of the first virtual receiving antenna based on the path difference, including: The phase difference between the first virtual receiving antenna and the second virtual receiving antenna is determined based on the path difference; Construct a steering vector based on the phase difference; The angle of arrival of the first virtual receiving antenna is determined based on the steering vector.

15. The apparatus according to claim 14, characterized in that, The phase difference satisfies the following formula: in, Let λ be the phase difference between the first virtual receiving antenna and the second virtual receiving antenna, λ be the operating wavelength of the antenna array of the MIMO radar, R1 be the first distance, and R j L1 is the second distance, and L2 is the fourth distance. i This refers to the third distance.

16. The apparatus according to claim 10, characterized in that, The calculation unit is further configured to determine the angle of arrival of the first virtual receiving antenna based on the path difference, including: The phase difference between the first virtual receiving antenna and the second virtual receiving antenna is determined based on the path difference; Construct a steering vector based on the phase difference; The angle of arrival of the first virtual receiving antenna is determined based on the steering vector; The phase difference satisfies the following formula: in, λ is the phase difference between the first virtual receiving antenna and the second virtual receiving antenna, λ is the operating wavelength of the antenna array of the MIMO radar, r1 is the measured value of the first distance, θ is the angle of arrival of the first virtual receiving antenna, d is the half wavelength of the antenna array of the MIMO radar, the kth virtual receiving antenna is the second virtual receiving antenna, and k is a positive integer less than or equal to MN.

17. The apparatus according to claim 16, characterized in that, The calculation unit is also used to make an accurate estimate based on the phase difference, which satisfies the following formula: Where, d q (θ) is the distance between the q-th virtual receiving antenna and the (q-1)-th virtual receiving antenna when the angle of arrival is θ.

18. The apparatus according to any one of claims 14 to 17, characterized in that, The computing unit is also used for: Based on the phase difference and the measured phase difference before calibration, the phase calibration coefficient for the antenna array calibration of the MIMO radar is determined.

19. A computer storage medium, characterized in that, The computer storage medium stores computer-executable instructions, which, when invoked by the computer, cause the computer to perform the method described in any one of claims 1 to 9.

20. A radar, characterized in that, include: There are M transmitting antennas, where M is a positive integer; There are N receiving antennas, where N is a positive integer, used to receive signals. And a processing unit, the processing unit being configured to perform the method as described in any one of claims 1 to 9.

21. A computing device, characterized in that, include: Memory, used to store computer programs. A processor for calling a computer program from the memory, which, when executed, causes the computing device to perform the method as described in any one of claims 1 to 9.

22. A vehicle-mounted system, characterized in that, include: There are M transmitting antennas, where M is a positive integer; There are N receiving antennas, where N is a positive integer, used to receive signals. as well as, The apparatus as described in any one of claims 10-18.

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