WO2021189268A1 - 一种雷达信号发射和接收方法及雷达 - Google Patents

一种雷达信号发射和接收方法及雷达 Download PDF

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Publication number
WO2021189268A1
WO2021189268A1 PCT/CN2020/080977 CN2020080977W WO2021189268A1 WO 2021189268 A1 WO2021189268 A1 WO 2021189268A1 CN 2020080977 W CN2020080977 W CN 2020080977W WO 2021189268 A1 WO2021189268 A1 WO 2021189268A1
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Prior art keywords
aliasing
coefficient
antenna
aliasing coefficient
overlapping
Prior art date
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PCT/CN2020/080977
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English (en)
French (fr)
Inventor
刘劲楠
杨晨
劳大鹏
朱金台
周沐
Original Assignee
华为技术有限公司
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Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP20926758.2A priority Critical patent/EP4119979A4/en
Priority to PCT/CN2020/080977 priority patent/WO2021189268A1/zh
Priority to CN202080098931.3A priority patent/CN115315636A/zh
Publication of WO2021189268A1 publication Critical patent/WO2021189268A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/42—Simultaneous measurement of distance and other co-ordinates
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S13/34—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
    • G01S13/343—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal using sawtooth modulation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/50—Systems of measurement based on relative movement of target
    • G01S13/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
    • G01S13/583—Velocity or trajectory determination systems; Sense-of-movement determination systems using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves and based upon the Doppler effect resulting from movement of targets
    • G01S13/584—Velocity or trajectory determination systems; Sense-of-movement determination systems using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves and based upon the Doppler effect resulting from movement of targets adapted for simultaneous range and velocity measurements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles

Definitions

  • This application relates to the field of sensor technology, and in particular to a radar signal transmitting and receiving method and radar.
  • Vehicle-mounted radar is an indispensable sensor in the automatic driving system.
  • the vehicle-mounted radar can provide obstacle (also called target) detection for the vehicle.
  • the vehicle-mounted radar can send a frequency modulated continuous wave (FMCW), and measure the distance, speed, and azimuth of the obstacle by detecting the reflected echo of the obstacle.
  • FMCW frequency modulated continuous wave
  • the frequency band has gradually evolved from 24GHz to 77GHz/79GHz, so as to obtain higher range resolution through larger scanning bandwidth;
  • the scan period from chirp is several ms level, which is reduced to ⁇ s level, which decouples the measurement distance and measurement speed, reduces the probability of false targets, and can effectively avoid non-ideal characteristics near DC;
  • the number of channels is changed by
  • the single-input multiple-output (SIMO) mode has evolved to the multiple-input multiple-output (MIMO) mode, and the antenna scale continues to expand, which expands the virtual antenna aperture and improves the angular resolution. It can meet the needs of achieving higher spatial resolution for the goal of autonomous driving.
  • TDM MIMO radar has the problem of decreasing the maximum speed range.
  • T SIMO the duration of a chirp sent by a single antenna
  • N Tx chirp signals in a time division manner requires at least N Tx time slots, that is, the duration of N Tx antennas transmitting N Tx chirps in a time division multiplexing manner
  • T MIMO N Tx *T SIMO .
  • V max_MIMO N Tx *V max_MIMO .
  • the maximum speed range is reduced compared with the SIMO radar. Moreover, the more the number of transmitting antennas N Tx , the more severe the decrease in the maximum speed range. When the maximum speed range is reduced, speed aliasing is more likely to occur when calculating the target's speed. In addition, due to the coupling of the velocity and angle measurement in the TDM MIMO radar, the velocity aliasing affects the solution of the angle, which fails to achieve the expected purpose of improving the spatial resolution of the target.
  • the embodiments of the present application provide a radar signal transmitting and receiving method and a radar, which are used to solve the problem that the phase difference of overlapping arrays is easily affected by noise, which in turn affects the correct solution of the speed of the target.
  • the present application provides a method for transmitting radar signals, which is applied to a MIMO radar.
  • the MIMO radar includes a transmitter and a receiver, the transmitter includes N Tx transmit antennas, and the receiver includes N Rx receivers.
  • Antenna wherein N Tx and N Rx are both positive integers greater than or equal to 2, and the method includes: determining configuration information of a measurement frame, wherein the configuration information of the measurement frame indicates the preset of the N Tx transmit antennas
  • the measurement frame is sent according to the configuration information of the measurement frame, so
  • the measurement frame includes U*N slow chirp signals, where the U*N slow chirp signals include N slow group chirp signals, each group of chirp signals includes U chirp signals, and the U chirp signals are the N
  • the Tx transmitting antennas respectively transmit in U time
  • the embodiment of the present application By adopting the design of the measurement frame provided by the embodiment of the present application, it is possible to construct overlapping arrays with multiple transmission intervals and increase the number of overlapping arrays through the preset transmission sequence of N Tx transmitting antennas. Compared with the number of overlapping elements in the prior art and the overlapping elements with a single emission interval, when the phase difference of the overlapping elements is greatly affected by noise, it will directly affect the correct solution of the target speed. However, because the embodiments of the present application construct multiple overlapping arrays with multiple transmission intervals and the number of overlapping arrays is large, even if the phase difference of the partially overlapping arrays is greatly affected by noise, it is possible to adjust the multiple overlapping arrays with multiple transmission intervals. The phase difference is processed to effectively reduce the influence of the phase difference of the overlapping arrays that is greatly affected by noise on the velocity solution, thereby improving the accuracy of the target velocity solution.
  • the transmitting antenna m1 transmits the chirp signal in the time slot u 1 of the U time slots, and the position of the virtual receiving antenna element formed by the transmitting antenna m1 and the receiving antenna n1 is d m1n1
  • the transmitting antenna m1’ transmits chirp signals in the time slot u 1 ’ of the U time slots
  • the position of the virtual receiving antenna element formed by the transmitting antenna m1’ and the receiving antenna n1’ is d m1’n1’
  • transmitting The antenna m2 transmits chirp signals in the time slot u 2 of the U time slots
  • the position of the virtual receiving antenna element formed by the transmitting antenna m2 and the receiving antenna n2 is d m2n2
  • the transmitting antenna m2' is in the U time slots slot u 2 'transmit chirp signal, transmit antenna m2' and the receiving antenna n2 'position of the virtual receive antenna elements
  • At least one of the N Tx transmit antennas has transmitted chirp signals twice in the U time slots.
  • the virtual receiving array formed by the N Tx transmitting antennas and the N Rx receiving antennas includes overlapping elements with a transmission interval of N 3 , where N 2 ⁇ N 2 ⁇ N 3 , where N 3 is Positive integer.
  • the values of N 1 and N 2 are determined by the antenna array and the preset transmission sequence.
  • N 1 and N 2 are generally smaller.
  • the present application provides a radar signal receiving method, which is applied to a MIMO radar.
  • the MIMO radar includes a transmitter and a receiver, the transmitter includes N Tx transmit antennas, and the receiver includes N Rx receivers.
  • Antenna wherein N Tx and N Rx are both positive integers greater than or equal to 2, and the method includes: receiving an echo signal formed after a measurement frame is reflected by at least one target, and the measurement frame includes U*N slow chirp signals , Wherein the U*N slow chirp signals include N slow group chirp signals, each group of chirp signals includes U chirp signals, and the U chirp signals are the N Tx transmitting antennas in U
  • the transmission duration T c of each chirp signal is recorded as a time slot; the virtual receiving array formed by the N Tx transmitting antennas and the N Rx receiving antennas includes the transmission interval of N 1 Overlapping elements and overlapping elements with a transmission interval of N 2 , N 1 ⁇ N 2 , N 1 is
  • the overlapping elements of multiple emission intervals can be calculated according to the number of overlapping elements and the number of overlapping elements.
  • the overlap coefficient even if the phase difference of the partially overlapped elements in the above-mentioned overlapped elements is greatly affected by noise, resulting in the inaccurate solution of the corresponding aliasing coefficients, the calculation of the target is solved according to the aliasing coefficients corresponding to the overlapped elements of various transmission intervals.
  • Speed can effectively reduce the influence of the aliasing coefficient corresponding to the overlapping arrays that is greatly affected by noise on the speed solution, and improve the accuracy of the target speed solution.
  • the above method will not cause the loss of the virtual antenna aperture.
  • the transmitting antenna m1 transmits the chirp signal in the time slot u 1 of the U time slots, and the position of the virtual receiving antenna element formed by the transmitting antenna m1 and the receiving antenna n1 is d m1n1
  • the transmitting antenna m1’ transmits chirp signals in the time slot u 1 ’ of the U time slots
  • the position of the virtual receiving antenna element formed by the transmitting antenna m1’ and the receiving antenna n1’ is d m1’n1’
  • transmitting The antenna m2 transmits chirp signals in the time slot u 2 of the U time slots
  • the position of the virtual receiving antenna element formed by the transmitting antenna m2 and the receiving antenna n2 is d m2n2
  • the transmitting antenna m2' is in the U time slots slot u 2 'transmit chirp signal, transmit antenna m2' and the receiving antenna n2 'position of the virtual receive antenna elements
  • the speed of the first target is determined according to the first aliasing coefficient and the second aliasing coefficient
  • the following design may be adopted: the range of the first aliasing coefficient is determined according to N 1 and the range of the first aliasing coefficient is determined according to N 2 Second aliasing coefficient range; determining a first set of aliasing coefficients according to the first aliasing coefficient range, the first aliasing coefficient, and N 1; and determining the first aliasing coefficient set according to the second aliasing coefficient range, the second The aliasing coefficient and N 2 determine the second set of aliasing coefficients; wherein, the first set of aliasing coefficients includes possible aliasing coefficients that convert the first aliasing coefficient to a third aliasing coefficient range, and the first aliasing coefficient
  • the set of two aliasing coefficients includes possible aliasing coefficients that convert the second aliasing coefficient to the third aliasing coefficient range, and the third aliasing
  • Coefficient range determining a third aliasing coefficient and a fourth aliasing coefficient according to the first set of aliasing coefficients and the second set of aliasing coefficients, the third aliasing coefficient being the first set of aliasing coefficients
  • the fourth aliasing coefficient is an aliasing coefficient in the second set of aliasing coefficients; the first aliasing coefficient is determined according to the third aliasing coefficient and the fourth aliasing coefficient The speed of a target.
  • the aliasing coefficients corresponding to the overlapping arrays with different transmission intervals can be converted to the aliasing coefficient range corresponding to the overlapping arrays with the transmission interval of 1, and then the maximum speed measurement range determined by Tc can be restored.
  • the difference between the third aliasing coefficient and the fourth aliasing coefficient is any one of the aliasing coefficients in the first set of aliasing coefficients and the second aliasing coefficient The minimum value of the difference of any aliasing coefficient in the set.
  • determining the speed of the first target according to the third aliasing coefficient and the fourth aliasing coefficient may adopt the following design: according to the third aliasing coefficient and the fourth aliasing coefficient The average value of the aliasing coefficient determines the speed of the first target; or, the speed of the first target is determined according to the weighted average value of the third aliasing coefficient and the fourth aliasing coefficient.
  • N 1 and N 2 are relatively prime.
  • the mutual prime of N 1 and N 2 can ensure that the third aliasing coefficient and the fourth aliasing coefficient determined by the first set of aliasing coefficients and the second set of aliasing coefficients are unique.
  • the virtual receiving array formed by the N Tx transmitting antennas and the N Rx receiving antennas includes overlapping elements with a transmission interval of N 3 , where N 2 ⁇ N 2 ⁇ N 3 , where N 3 is Positive integer.
  • an embodiment of the present application also provides a radar device, the device includes a transmitter, a receiver, and a processing unit, the transmitter includes N Tx transmitting antennas, and the receiver includes N Rx receiving antennas, Among them, N Tx and N Rx are both positive integers greater than or equal to 2, where:
  • the processing unit is configured to determine configuration information of a measurement frame, where the configuration information of the measurement frame indicates the preset transmission sequence of the N Tx transmitting antennas, the transmission duration T c of each chirp signal, and The number of repeated transmissions of the N Tx transmitting antennas according to the preset transmission sequence N slow ;
  • the transmitter is configured to send the measurement frame according to the configuration information of the measurement frame, the measurement frame includes U*N slow chirp signals, wherein the U*N slow chirp signals include N slow group chirps signals, each set comprising a chirp signal U a chirp signal, a chirp signal of the U N Tx is the transmit antennas transmit according to the preset sequence U are transmitted slots, the duration of each transmission of the chirp signal T c is denoted as a time slot; the virtual receiving array formed by the N Tx transmitting antennas and the N Rx receiving antennas includes overlapping elements with a transmission interval of N 1 and overlapping elements with a transmission interval of N 2 , N 1 ⁇ N 2 , N 1 is a positive integer, N 2 is a positive integer, U ⁇ N Tx .
  • the transmitting antenna m1 transmits the chirp signal in the time slot u 1 of the U time slots, and the position of the virtual receiving antenna element formed by the transmitting antenna m1 and the receiving antenna n1 is d m1n1
  • the transmitting antenna m1’ transmits chirp signals in the time slot u 1 ’ of the U time slots
  • the position of the virtual receiving antenna element formed by the transmitting antenna m1’ and the receiving antenna n1’ is d m1’n1’
  • transmitting The antenna m2 transmits chirp signals in the time slot u 2 of the U time slots
  • the position of the virtual receiving antenna element formed by the transmitting antenna m2 and the receiving antenna n2 is d m2n2
  • the transmitting antenna m2' is in the U time slots slot u 2 'transmit chirp signal, transmit antenna m2' and the receiving antenna n2 'position of the virtual receive antenna elements
  • At least one of the N Tx transmit antennas has transmitted chirp signals twice in the U time slots.
  • the virtual receiving array formed by the N Tx transmitting antennas and the N Rx receiving antennas includes overlapping elements with a transmission interval of N 3 , where N 2 ⁇ N 2 ⁇ N 3 , where N 3 is Positive integer.
  • an embodiment of the present application provides a radar device, the device is a MIMO radar, the MIMO radar includes a transmitter, a receiver, and a processing unit, the transmitter includes N Tx transmit antennas, and the receiver Including N Rx receiving antennas, where N Tx and N Rx are both positive integers greater than or equal to 2, where:
  • the receiver is configured to receive an echo signal formed after a measurement frame is reflected by at least one target, the measurement frame includes U*N slow chirp signals, wherein the U*N slow chirp signals include N slow groups A chirp signal, each group of chirp signals includes U chirp signals, and the U chirp signals are respectively transmitted by the N Tx transmitting antennas in U time slots according to a preset transmission sequence, and the transmission duration of each chirp signal is T c is denoted as a time slot;
  • the virtual receiving array formed by the N Tx transmitting antennas and the N Rx receiving antennas includes overlapping elements with a transmission interval of N 1 and overlapping elements with a transmission interval of N 2 , N 1 ⁇ N 2 , N 1 is a positive integer, N 2 is a positive integer, U ⁇ N Tx ;
  • the processing unit is configured to determine a first aliasing coefficient and a second aliasing coefficient according to the echo signal; wherein, the first aliasing coefficient corresponds to an overlapping array with a transmission interval of N 1 corresponding to the first target
  • the second aliasing coefficient is the aliasing coefficient corresponding to the overlapping array with a transmission interval of N 2 corresponding to the first target, and the first target is any one of the at least one target ; Determine the speed of the first target according to the first aliasing coefficient and the second aliasing coefficient.
  • the transmitting antenna m1 transmits the chirp signal in the time slot u 1 of the U time slots, and the position of the virtual receiving antenna element formed by the transmitting antenna m1 and the receiving antenna n1 is d m1n1
  • the transmitting antenna m1’ transmits chirp signals in the time slot u 1 ’ of the U time slots
  • the position of the virtual receiving antenna element formed by the transmitting antenna m1’ and the receiving antenna n1’ is d m1’n1’
  • transmitting The antenna m2 transmits chirp signals in the time slot u 2 of the U time slots
  • the position of the virtual receiving antenna element formed by the transmitting antenna m2 and the receiving antenna n2 is d m2n2
  • the transmitting antenna m2' is in the U time slots slot u 2 'transmit chirp signal, transmit antenna m2' and the receiving antenna n2 'position of the virtual receive antenna elements
  • the processing unit is configured to: determine a first aliasing coefficient range according to N 1 and determine a second aliasing coefficient range according to N 2 ;
  • the first aliasing coefficient and N 1 determine a first set of aliasing coefficients
  • the second set of aliasing coefficients is determined according to the second aliasing coefficient range, the second aliasing coefficient, and N 2 ;
  • the The first set of aliasing coefficients includes the possible aliasing coefficients that convert the first aliasing coefficient to a third range of aliasing coefficients
  • the second set of aliasing coefficients includes the conversion of the second aliasing coefficients to the Possible aliasing coefficients in the third aliasing coefficient range, where the third aliasing coefficient range is the aliasing coefficient range corresponding to the overlapping array with a transmission interval of 1; according to the first set of aliasing coefficients and the second set of aliasing coefficients
  • the set of aliasing coefficients includes the
  • the difference between the third aliasing coefficient and the fourth aliasing coefficient is any one of the aliasing coefficients in the first set of aliasing coefficients and the second aliasing coefficient The minimum value of the difference of any aliasing coefficient in the set.
  • the processing unit is configured to: determine the speed of the first target according to the average value of the third aliasing coefficient and the fourth aliasing coefficient; or, according to the first target The weighted average of the three aliasing coefficients and the fourth aliasing coefficient determines the speed of the first target.
  • the virtual receiving array formed by the N Tx transmitting antennas and the N Rx receiving antennas includes overlapping elements with a transmission interval of N 3 , where N 2 ⁇ N 2 ⁇ N 3 , where N 3 is Positive integer.
  • FIG. 1 is a schematic diagram of the structure of the MIMO radar system of this application.
  • FIG. 2 is a functional block diagram of a vehicle 200 with an automatic driving function in this application;
  • FIG. 3 is one of the schematic diagrams of the horizontal array of 3 transmitting antennas and 4 receiving antennas forming 2 pairs of overlapping arrays in this application;
  • FIG. 4 is an overview flowchart of a radar signal transmission method in this application.
  • Fig. 5 is the second schematic diagram of the horizontal array of 3 transmitting antennas and 4 receiving antennas forming 2 pairs of overlapping arrays in this application;
  • 6(a) to 6(c) are schematic diagrams of the transmission sequence of a possible transmitting antenna in this application;
  • FIG. 7 is a schematic diagram of aliasing coefficient ranges corresponding to overlapping arrays of different transmission intervals in this application.
  • Figure 8 is a schematic diagram of the structure of a radar in this application.
  • the MIMO radar system may include an antenna array 101, a microwave integrated circuit (monolithic microwave integrated circuit, MMIC) 102, and a processing unit 103.
  • the antenna array 101 may include multiple transmitting antennas and multiple receiving antennas.
  • the microwave integrated circuit 102 is used to generate radar signals, and then send the radar signals through the antenna array 101.
  • the radar signal includes multiple chirp signals. After the radar signal is sent out, it is reflected by one or more targets to form an echo signal, and the echo signal is received by the receiving antenna.
  • the microwave integrated circuit 102 is also used to transform and sample the echo signal received by the antenna array 101, and transmit the processed echo signal to the processing unit 103.
  • the processing unit 103 is used to perform Fast Fourier Transformation (FFT), signal processing and other operations on the echo signal, so as to determine the distance, speed, azimuth angle and other information of the target according to the received echo signal.
  • the processing unit 103 may be a microprocessor (microcontroller unit, MCU), a central processing unit (CPU), a digital signal processor (digital signal processor, DSP), or a field programmable gate array (field-programmable gate array).
  • Programmable gate array, FPGA dedicated accelerators and other devices with processing functions.
  • the radar system shown in FIG. 1 may also include an electronic control unit (ECU) 104, which is used to control the vehicle according to the target distance, speed, azimuth and other information processed by the processing unit 103, such as determining The route of the vehicle, the speed of the vehicle, etc.
  • ECU electronice control unit
  • the transmitter in the embodiment of the present application may be composed of a transmitting antenna and a transmitting channel in the microwave integrated circuit 102
  • the receiver may be composed of a receiving antenna and a receiving channel in the microwave integrated circuit 102.
  • the transmitting antenna and the receiving antenna can be located on a printed circuit board (PCB), and the transmitting channel and the receiving channel can be located in the chip, namely AOB (antenna on PCB); or, the transmitting antenna and the receiving antenna can be located on the chip package Inside, the transmitting channel and the receiving channel can be located in the chip, that is, AIP (antenna in package).
  • the combination form is not specifically limited. It should be understood that the specific structures of the transmitting channel and the receiving channel are not limited in the embodiments of the present application, as long as the corresponding transmitting and receiving functions can be realized.
  • the entire radar system may include multiple radio frequency chip cascades.
  • the transmitting antenna array and the receiving antenna array are obtained by cascading multiple MIMO, and the data output by the analog digital converter (analog digital converter, ADC) channel is connected through the interface.
  • ADC analog digital converter
  • MMIC and DSP can be integrated in one chip, which is called System on Chip (SOC).
  • the MMIC and ADC, and the processing unit 103 can be integrated in one chip to form an SOC.
  • the entire vehicle may be equipped with one or more radar systems, which are connected to the central processing unit through the on-board bus.
  • the central processing unit controls one or more on-board sensors, including one or more millimeter wave radar sensors.
  • the MIMO radar system shown in Figure 1 can be applied to vehicles with autonomous driving functions.
  • FIG. 2 is a functional block diagram of a vehicle 200 with an automatic driving function provided in an embodiment of this application.
  • the vehicle 200 is configured in a fully or partially autonomous driving mode.
  • the vehicle 200 can control itself at the same time in the automatic driving mode, and can determine the current state of the vehicle and its surrounding environment through manual operation, determine the possible behavior of at least one other vehicle in the surrounding environment, and determine the other vehicle The confidence level corresponding to the possibility of performing the possible behavior, and the vehicle 200 is controlled based on the determined information.
  • the vehicle 200 may be placed to operate without human interaction.
  • the vehicle 200 may include various subsystems, such as a travel system 202, a sensor system 204, a control system 206, one or more peripheral devices 208 and a power supply 210, a computer system 212, and a user interface 216.
  • the vehicle 200 may include more or fewer subsystems, and each subsystem may include multiple elements.
  • each subsystem and element of the vehicle 200 may be interconnected by wire or wirelessly.
  • the travel system 202 may include components that provide power movement for the vehicle 200.
  • the travel system 202 may include an engine 218, an energy source 219, a transmission 220, and wheels/tires 221.
  • the engine 218 may be an internal combustion engine, an electric motor, an air compression engine, or a combination of other types of engines, such as a hybrid engine composed of a gas oil engine and an electric motor, or a hybrid engine composed of an internal combustion engine and an air compression engine.
  • the engine 218 converts the energy source 219 into mechanical energy.
  • Examples of energy sources 219 include gasoline, diesel, other petroleum-based fuels, propane, other compressed gas-based fuels, ethanol, solar panels, batteries, and other sources of electricity.
  • the energy source 219 may also provide energy for other systems of the vehicle 200.
  • the transmission 220 can transmit the mechanical power from the engine 218 to the wheels 221.
  • the transmission 220 may include a gearbox, a differential, and a drive shaft.
  • the transmission device 220 may also include other devices, such as a clutch.
  • the drive shaft may include one or more shafts that can be coupled to one or more wheels 221.
  • the sensor system 204 may include several sensors that sense information about the environment around the vehicle 200.
  • the sensor system 204 may include a positioning system 222 (the positioning system may be a global positioning system (GPS) system, a Beidou system or other positioning systems), an inertial measurement unit (IMU) 224, Radar 226, laser rangefinder 228, and camera 230.
  • the sensor system 204 may also include sensors of the internal system of the monitored vehicle 200 (for example, 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 corresponding characteristics (position, shape, direction, speed, etc.). Such detection and identification are key functions for the safe operation of the vehicle 200.
  • the positioning system 222 can be used to estimate the geographic location of the vehicle 200.
  • the IMU 224 is used to sense changes in the position and orientation of the vehicle 200 based on inertial acceleration.
  • the IMU 224 may be a combination of an accelerometer and a gyroscope.
  • the radar 226 may use radio signals to sense targets in the surrounding environment of the vehicle 200. In some embodiments, in addition to sensing the target, the radar 226 can also be used to sense the speed and/or heading of the target. In a specific example, the radar 226 can be implemented using the MIMO radar system shown in FIG. 1.
  • the laser rangefinder 228 can use laser light to sense a target in the environment where the vehicle 100 is located.
  • the laser rangefinder 228 may include one or more laser sources, laser scanners, and one or more detectors, as well as other system components.
  • the camera 230 may be used to capture multiple images of the surrounding environment of the vehicle 200.
  • the camera 230 may be a still camera or a video camera.
  • the control system 206 controls the operation of the vehicle 200 and its components.
  • the control system 206 may include various components, including a steering system 232, a throttle 234, a braking unit 236, a sensor fusion algorithm 238, a computer vision system 240, a route control system 242, and an obstacle avoidance system 244.
  • the steering system 232 is operable to adjust the forward direction of the vehicle 200.
  • it may be a steering wheel system.
  • the throttle 234 is used to control the operating speed of the engine 218 and thereby control the speed of the vehicle 200.
  • the braking unit 236 is used to control the vehicle 200 to decelerate.
  • the braking unit 236 may use friction to slow down the wheels 221.
  • the braking unit 236 may convert the kinetic energy of the wheels 221 into electric current.
  • the braking unit 236 may also take other forms to slow down the rotation speed of the wheels 221 so as to control the speed of the vehicle 200.
  • the computer vision system 240 may be operable to process and analyze the images captured by the camera 230 in order to identify objects and/or features in the surrounding environment of the vehicle 200.
  • the targets and/or features may include traffic signals, road boundaries, and obstacles.
  • the computer vision system 240 may use target recognition algorithms, structure from motion (SFM) algorithms, video tracking, and other computer vision technologies.
  • the computer vision system 240 may be used to map the environment, track targets, estimate the speed of targets, and so on.
  • the route control system 242 is used to determine the travel route of the vehicle 200.
  • the route control system 142 may combine data from the sensor 238, the GPS 222, and one or more predetermined maps to determine the driving route for the vehicle 200.
  • the obstacle avoidance system 244 is used to identify, evaluate, and avoid or otherwise cross over potential obstacles in the environment of the vehicle 200.
  • control system 206 may additionally or alternatively include components other than those shown and described. Alternatively, a part of the components shown above may be reduced.
  • the vehicle 200 interacts with external sensors, other vehicles, other computer systems, or users through peripheral devices 208.
  • the peripheral device 208 may include a wireless communication system 246, an onboard computer 248, a microphone 250, and/or a speaker 252.
  • the peripheral device 208 provides a means for the user of the vehicle 200 to interact with the user interface 216.
  • the onboard computer 248 can provide information to the user of the vehicle 200.
  • the user interface 216 can also operate the onboard computer 248 to receive user input.
  • the on-board computer 248 can be operated via a touch screen.
  • the peripheral device 208 may provide a means for the vehicle 200 to communicate with other devices located in the vehicle.
  • the microphone 250 may receive audio (eg, voice commands or other audio input) from a user of the vehicle 200.
  • the speaker 252 may output audio to the user of the vehicle 200.
  • the wireless communication system 246 may wirelessly communicate with one or more devices directly or via a communication network.
  • the wireless communication system 246 may use 3G cellular communication, such as code division multiple access (CDMA), EVD0, global system for mobile communications (GSM)/general packet radio service technology (general packet) radio service, GPRS), or 4G cellular communication, such as long term evolution (LTE), or 5G cellular communication.
  • the wireless communication system 246 may use WiFi to communicate with a wireless local area network (WLAN).
  • the wireless communication system 246 may directly communicate with the device using an infrared link, Bluetooth, or ZigBee.
  • Other wireless protocols such as various vehicle communication systems.
  • the wireless communication system 246 may include one or more dedicated short-range communications (DSRC) devices, which may include vehicles and/or roadside stations. Public and/or private data communications.
  • DSRC dedicated short-range communications
  • the power supply 210 may provide power to various components of the vehicle 200.
  • the power source 210 may be a rechargeable lithium ion or lead-acid battery.
  • One or more battery packs of such batteries may be configured as a power source to provide power to various components of the vehicle 200.
  • the power source 210 and the energy source 219 may be implemented together, such as in some all-electric vehicles.
  • the computer system 212 may include at least one processor 223 that executes instructions 225 stored in a non-transitory computer readable medium such as the memory 224.
  • the computer system 212 may also be multiple computing devices that control individual components or subsystems of the vehicle 200 in a distributed manner.
  • the processor 223 may be any conventional processor, such as a commercially available central processing unit (CPU). Alternatively, the processor may be a dedicated device such as an application specific integrated circuit (ASIC) or other hardware-based processor.
  • FIG. 2 functionally illustrates the processor, memory, and other elements of the computer 210 in the same block, those of ordinary skill in the art should understand that the processor, computer, or memory may actually include Multiple processors, computers, or memories stored in the same physical enclosure.
  • the memory may be a hard disk drive or other storage medium located in a housing other than the computer 210. Therefore, a reference to a processor or computer will be understood to include a reference to a collection of processors or computers or memories that may or may not operate in parallel. Rather than using a single processor to perform the steps described here, some components such as steering components and deceleration components may each have its own processor that only performs calculations related to component-specific functions .
  • the processor may be located away from the vehicle and wirelessly communicate with the vehicle.
  • some of the processes described herein are executed on a processor disposed in the vehicle and others are executed by a remote processor, including taking the necessary steps to perform a single manipulation.
  • the memory 224 may contain instructions 225 (eg, program logic), which may be executed by the processor 223 to perform various functions of the vehicle 200, including those functions described above.
  • the memory 214 may also contain additional instructions, including those for sending data to, receiving data from, interacting with, and/or controlling one or more of the traveling system 202, the sensor system 204, the control system 206, and the peripheral device 208. instruction.
  • the memory 224 may also store data, such as road maps, route information, the location, direction, and speed of the vehicle, and other such vehicle data, as well as other information. Such information may be used by the vehicle 200 and the computer system 212 during operation of the vehicle 200 in autonomous, semi-autonomous, and/or manual modes.
  • the user interface 216 is used to provide information to or receive information from a user of the vehicle 200.
  • the user interface 216 may include one or more input/output devices in the set of peripheral devices 208, such as a wireless communication system 246, a car computer 248, a microphone 250, and a speaker 252.
  • the computer system 212 may control the functions of the vehicle 200 based on inputs received from various subsystems (eg, the travel system 202, the sensor system 204, and the control system 206) and from the user interface 216.
  • the computer system 212 may utilize input from the control system 206 in order to control the steering unit 232 to avoid obstacles detected by the sensor system 204 and the obstacle avoidance system 244.
  • the computer system 212 is operable to provide control of many aspects of the vehicle 200 and its subsystems.
  • one or more of the aforementioned components may be installed or associated with the vehicle 200 separately.
  • the storage 224 may exist partially or completely separately from the vehicle 200.
  • the above-mentioned components may be communicatively coupled together in a wired and/or wireless manner.
  • FIG. 2 should not be construed as a limitation to the embodiment of the present application.
  • a self-driving car traveling on a road can identify targets in its surrounding environment to determine adjustments to the current speed.
  • the target may be other vehicles, traffic control equipment, or other types of targets.
  • each recognized target can be considered independently, and based on the respective characteristics of the target, such as its current speed, acceleration, distance from the vehicle, etc., can be used to determine the speed to be adjusted by the autonomous vehicle.
  • the self-driving car 200 or the computing device associated with the self-driving vehicle 200 may be based on the characteristics of the identified target and the state of the surrounding environment (For example, traffic, rain, ice on the road, etc.) to predict the behavior of the identified target.
  • each identified target depends on each other's behavior, so all the identified targets can also be considered together to predict the behavior of a single identified target.
  • the vehicle 200 can adjust its speed based on the predicted behavior of the identified target.
  • an autonomous vehicle can determine what stable state the vehicle will need to adjust to (for example, accelerating, decelerating, or stopping) based on the predicted behavior of the target.
  • other factors may also be taken into consideration to determine the speed of the vehicle 200, such as the lateral position of the vehicle 200 on the traveling road, the curvature of the road, the proximity of static and dynamic targets, and so on.
  • the computing device can also provide instructions to modify the steering angle of the vehicle 200 so that the self-driving car follows a given trajectory and/or maintains a target near the self-driving car (for example, , The safe horizontal and vertical distances of cars in adjacent lanes on the road.
  • the above-mentioned vehicle 200 can be a car, truck, motorcycle, bus, boat, airplane, helicopter, lawn mower, recreational vehicle, playground vehicle, construction equipment, tram, golf cart, train, and trolley, etc.
  • the application examples are not particularly limited.
  • the radar system described in the embodiments of the present application can be applied to various fields.
  • the radar systems in the embodiments of the present application include, but are not limited to, vehicle-mounted radars, roadside traffic radars, etc. Man-machine radar.
  • this application provides a method for transmitting and receiving radar signals.
  • the method is applied to a MIMO radar.
  • the MIMO radar includes a transmitter, a receiver, and a processing unit.
  • the transmitter includes N Tx transmit antennas, and the receiver includes N Rx receivers.
  • the method includes:
  • Step 400 The processing unit determines the configuration information of the measurement frame, where the configuration information of the measurement frame indicates the preset transmission sequence of the N Tx transmit antennas, the transmission duration of each chirp signal T c and the N Tx transmit antennas are in accordance with the preset The number of times the transmission sequence repeats the transmission N slow .
  • the configuration information of the measurement frame includes the preset transmission order of N Tx transmitting antennas, T c and N slow , or the preset transmission order of N Tx transmitting antennas, U*T c and N slow . It should be understood that this application does not limit the specific form of the configuration information of the measurement frame.
  • the processing unit After the processing unit determines the configuration information of the measurement frame, it sends the configuration information of the measurement frame to the single-chip or multi-chip MMIC through the interface.
  • the single-chip or multi-chip MMIC is used to enable the transmitter to send the measurement frame according to the configuration information of the measurement frame .
  • Step 410 The transmitter sends the measurement frame according to the configuration information of the measurement frame.
  • the measurement frame includes U*N slow chirp signals, where U*N slow chirp signals include N slow group chirp signals, and each group of chirp signals includes U chirp signals.
  • Signal, U chirp signals are respectively transmitted by N Tx transmitting antennas in U time slots according to the preset transmission sequence.
  • the transmission duration T c of each chirp signal is recorded as a time slot; N Tx transmitting antennas and N Rx
  • the virtual receiving array formed by the receiving antennas includes overlapping arrays with a transmission interval of N 1 and overlapping arrays with a transmission interval of N 2 , N 1 ⁇ N 2 , N 1 is a positive integer, N 2 is a positive integer, U ⁇ N Tx .
  • the transmitting antenna m1 transmits chirp signals in the time slot u 1 of the U time slots
  • the position of the virtual receiving antenna element formed by the transmitting antenna m1 and the receiving antenna n1 is d m1n1
  • the transmitting antenna m1' is in U-slot in the slot u 'chirp signal transmitter
  • the transmitting antenna m1' 1 and the receiving antenna n1 'position of the virtual receive antenna elements are formed is d m1'n1'
  • the transmitting antenna and the receiving antenna m2 n2 forming position of the virtual receive antenna elements is d m2n2
  • transmit antenna m2 ' The position of the virtual receiving antenna element formed by the receiving antenna n2' is d m2'n2' , the
  • the measurement frame may be FMCW, or other waveforms used by MIMO radars.
  • the measurement frame may also be a pulse waveform or an Orthogonal Frequency Division Multiplex (OFDM) waveform.
  • OFDM Orthogonal Frequency Division Multiplex
  • N 1 and N 2 are relatively prime.
  • the values of N 1 and N 2 are determined by the antenna array and preset sequence. It can be understood that since the smaller the value of the transmission interval, the larger the corresponding velocity measurement range, and a smaller multiple of aliasing can be achieved. Therefore, the values of N 1 and N 2 are generally smaller.
  • the virtual receiving array formed by N Tx transmitting antennas and N Rx receiving antennas includes overlapping arrays with a transmission interval of N 3 , N 1 ⁇ N 2 ⁇ N 3 , and N 3 is a positive integer .
  • the antenna synthesized by the transmitting antenna and the receiving antenna is a virtual receiving antenna, which can also be described as a virtual receiving array synthesized by the transmitting antenna and the receiving antenna.
  • the number of transmitting antennas is N Tx
  • the number of receiving antennas is N Rx .
  • the coordinate position of the transmitting antenna Tx i is expressed in a two-dimensional plane as (x i , y i ), where 1 ⁇ i ⁇ N Tx ; the coordinate position of the receiving antenna Rx i is expressed in a two-dimensional plane as (x i , y i ), Among them, 1 ⁇ j ⁇ N Rx , then a total of N Tx *N Rx virtual arrays can be obtained.
  • d k represents a virtual antenna position formed by N Rx received signals arranged in a preset transmission order and sequence.
  • k (u-1)*N Rx +n Rx , 1 ⁇ k ⁇ U*N Rx, 1 ⁇ u ⁇ U, 1 ⁇ n Rx ⁇ N Rx
  • the coordinate position of the transmitting antenna m in the two-dimensional plane is expressed as (x m , y m ) u , where 1 ⁇ m ⁇ N Tx
  • the coordinate position of the receiving antenna n in the two-dimensional plane is expressed as (x n , y n ) u , Where 1 ⁇ n ⁇ N Rx .
  • the prior art only includes overlapping arrays with a transmission interval of 1, and only includes overlapping arrays formed by hardware, and does not include overlapping arrays formed by multiple transmissions of the same transmitting antenna when U>N Tx .
  • the method of forming overlapping arrays can include but is not limited to the following two methods:
  • Method 1 The overlapping arrays are formed by the deployment of different antennas.
  • the overlapping array formed by using method 1 can also be referred to as the overlapping array on the hardware.
  • One-dimensional array refers to the situation where the vertical Y-axis coordinate position of each element in the transmitting antenna array is the same, and the vertical Y-axis coordinate position of each element in the receiving antenna array is the same.
  • the one-dimensional array can only obtain the horizontal angle of the target, that is, horizontal Array.
  • a two-dimensional array means that the Y-axis coordinate of each element in the transmitting antenna array has at least one element position that is different from other elements, and the Y-axis coordinate of each element in the receiving antenna array has one element position that is different from other elements.
  • the two-dimensional array includes one or more one-dimensional sub-arrays.
  • a one-dimensional horizontal array of 3 transmitting antennas and 4 receiving antennas forms a schematic diagram of 2 pairs of overlapping arrays.
  • the spacing of the transmitting antennas is a horizontal array of 3 ⁇ /2
  • the virtual receiving array there are overlapping arrays with a transmission interval of 2 at the position of 3 ⁇ /2 and overlapping arrays with a transmission interval of 1 at the position of 3 ⁇ . It can be seen that when the transmission sequence changes from 1, 2, 3 to 1, At 3 and 2, this change in the firing sequence will not cause the position of the overlapping array to change, and only affect the firing interval.
  • Method 2 Overlapping arrays are formed by the same antenna occupying different transmitting moments.
  • At least one of the N Tx transmit antennas transmits chirp signals twice in U transmit time slots.
  • the overlapping array formed by using method 1 can also be called the overlapping array on the software, or the soft overlapping array.
  • 1 and 1 marked by thick lines form 4 pairs of overlapping arrays on the receiving side, and the transmission intervals of these 4 pairs of overlapping arrays are the same, and they are all 2.
  • 3 and 3 marked by thick lines form 4 pairs of overlapping elements on the receiving side, and the transmission intervals of these 4 pairs of overlapping elements are the same, and they are all 2.
  • 2 and 2 connected by the connecting line form 4 pairs of overlapping arrays on the receiving side, and the transmission intervals of these 4 pairs of overlapping arrays are the same, and they are all 3.
  • the two pairs of 3 and 3 connected by the connecting line form 2*4 pairs of overlapping arrays on the receiving side, and the transmission intervals of the 8 pairs of overlapping arrays are the same, and they are all 3.
  • the overlapping elements formed by mode 1 include: the overlapping elements with a transmission interval of 1 are: transmitting antenna 2 and transmitting antenna 1 (denoted by 2-1 ) A pair of overlapping elements is formed on the receiving side, the transmitting antenna 1 and the transmitting antenna (indicated by 1-2) 2 form a pair of overlapping elements on the receiving side, and the transmitting antenna 3 and the transmitting antenna 2 (indicated by 3-2) are on the receiving side. A pair of overlapping elements is formed, and the transmitting antenna 2 and the transmitting antenna 3 (indicated by 2-3) form a pair of overlapping elements on the receiving side.
  • the overlapping arrays with a transmission interval of 2 are as follows: the transmitting antenna 2 and the transmitting antenna 1 separated by 1 (indicated by 2-1-1) form a pair of overlapping arrays on the receiving side, the transmitting antenna 1 and the transmitting antenna 2 separated by 1 (Indicated by 1-1-2) A pair of overlapping elements is formed on the receiving side, and the transmitting antenna 3 and the transmitting antenna 2 separated by one (indicated by 3-3-2) form a pair of overlapping elements on the receiving side, and the transmitting antenna 2. A pair of overlapping arrays is formed on the receiving side with the transmitting antenna 3 (indicated by 2-3-3) separated by one.
  • the number of overlapping elements with a transmission interval of 3 in the two ways and the number of overlapping elements with other transmission intervals can be further counted, which is not limited in this application.
  • the construction of overlapping elements with multiple transmission intervals and the increase of the number of overlapping elements can be realized through the preset transmission sequence of NTx transmitting antennas.
  • the phase difference of the overlapping arrays is greatly affected by noise, it will directly affect the correct solution of the target speed.
  • the embodiments of the present application construct multiple overlapping arrays with multiple transmission intervals and the number of overlapping arrays is large, even if the phase difference of the partially overlapping arrays is greatly affected by noise, it is possible to adjust the multiple overlapping arrays with multiple transmission intervals.
  • the phase difference is processed to effectively reduce the influence of the phase difference of the overlapping arrays that is greatly affected by noise on the velocity solution, thereby improving the accuracy of the target velocity solution.
  • Step 420 The receiver receives the echo signal formed after the measurement frame sent by the transmitter is reflected by one or more targets.
  • the receiver comprises N Rx receive antennas, N Rx receiving antennas according to the transmission order of N Tx transmitting antennas, receiving U received signals, and then in accordance with N Tx transmitting antennas, and The positional relationship between the N Rx receiving antennas and the transmitting sequence of the transmitting antennas convert the received U receiving signals into echo signals.
  • N slow is the number of repeated transmissions according to the preset sequence, N slow echo signals are obtained.
  • U represents the number of time slots in which different antennas transmit signals in a repetition period according to the TDM method, and the transmission period is U*T c , where the same antenna can transmit multiple times in U time slots.
  • one of the U received signals is a chirp signal formed after a transmitted chirp signal is reflected by one or more targets.
  • Step 430 The processing unit determines the first aliasing coefficient and the second aliasing coefficient.
  • the first aliasing coefficient is the aliasing coefficient corresponding to the overlapping array with the transmission interval of N 1 corresponding to the first target
  • the second aliasing coefficient is the aliasing coefficient corresponding to the overlapping array with the transmission interval of N 2 corresponding to the first target.
  • the first target is any one of at least one target.
  • a signal within a single chirp is called fast chirp, which can obtain distance information of a target, and multiple chirp signals are called forming a slow chirp, and speed information of the target can be obtained.
  • the processing unit calculates the fast Fourier transform of the distance dimension corresponding to each fast chirp, and further, on the basis of the fast chirp fft, calculates the speed dimension fast Fourier on different slow chirps on the same distance unit (Range bin) Transform to obtain the two-dimensional Fourier transform results of U*N Rx virtual receiving elements.
  • the two-dimensional Fourier transform result of a virtual receiving array refers to a range-Doppler map (Range-Doppler Map) corresponding to the virtual receiving array.
  • N s sampling points are obtained in a fast chirp, and the N range point distance dimension fast Fourier transform is performed; N slow sampling points are obtained on the slow chirp, and N doppler point speed is obtained.
  • the dimensional fast Fourier transform obtains the RD patterns corresponding to U*N Rx virtual receiving arrays.
  • the processing unit accumulates the two-dimensional Fourier transform results of U*N Rx virtual receiving arrays to obtain a total RD graph.
  • the accumulation of the two-dimensional Fourier transform results of U*N Rx virtual receiving elements can be incoherent superposition, that is, the two-dimensional Fourier amplitude superposition of U*N Rx virtual receiving elements, or incoherent superposition , That is , the complex superposition of two-dimensional Fourier peaks synthesized on a fixed beam of U*N Rx virtual receiving elements, or other superposition methods, which are not particularly limited in this application.
  • RD graph one dimension is distance information, and one dimension is radar output graph of Doppler information. Extracting from the distance dimension is called Range bin, and extracting from the Doppler dimension is called Doppler bin. At the same time, extracting from the distance and Doppler dimensions is called Range-Doppler Cell.
  • the processing unit detects the target on the total RD graph.
  • the processing unit may use various existing detection methods for detection, such as ordered statistics-constant false alarm rate (detection) (Ordered Statistic-Constant False Alarm Rate, OS-CFAR) or unit average-constant false alarm Common detection methods such as Cell-Averaging Constant False Alarm Rate (CA-CFAR) are not limited in this application.
  • detection ordered statistics-constant false alarm rate
  • OS-CFAR Orderered Statistic-Constant False Alarm Rate
  • CA-CFAR Cell-Averaging Constant False Alarm Rate
  • the processing unit After the processing unit detects a target on the total RD diagram, the processing unit extracts the signal of the overlapped matrix corresponding to the target on the total RD diagram.
  • the signal of the overlapped element corresponding to each target on the total RD pattern includes the signal of the overlapped element with a transmission interval of N 1 on the total RD pattern and the signal of the overlapped matrix with a transmission interval of N 2 on the total RD pattern.
  • the processing unit may determine the first aliasing coefficient in but not limited to the following manner, and the processing unit may determine the second aliasing coefficient in the same manner, and the repetition will not be repeated.
  • N ii , and the transmission interval corresponding to the overlapping element is N ii .
  • the transmitting antenna m transmits the chirp signal in the time slot u. If the waveform of the signal is expressed as S(t), the distance R i is passed, the radial velocity is V i , and the horizontal angle is ⁇ i (in horizontal).
  • the virtual receiving element formed by the transmitting antenna m and the receiving antenna n can represent the target detection distance and the identification of the aliased velocity (R ind , V ind ) obtained from the total RD graph, where the measured
  • the target distance can be expressed as Where R Res is the distance resolution.
  • On the RD graph corresponding to the virtual receiving element take the complex value in the RD unit corresponding to (R ind ,V ind)
  • the phase of the complex value It can be expressed as:
  • Vi_amb is the speed after aliasing obtained through the total RD map, namely Is the speed resolution. Further, it can be based on Traverse each value in the range of k Nii to make the expression closest to 0 Is the aliasing coefficient. Is the signal corresponding to d mn on the RD graph corresponding to the virtual receiving period, Is the signal corresponding to d m′n′ on the RD diagram corresponding to the virtual receiving element, The value range of is determined by the transmission interval N ii.
  • Step 440 The processing unit determines the speed of the first target according to the first aliasing coefficient and the second aliasing coefficient.
  • the processing unit may adopt but not limited to the following methods to determine the speed of the first target:
  • the processing unit determines the first aliasing coefficient range according to N 1 and determines the second aliasing coefficient range according to N 2 .
  • the velocity measurement range of overlapping arrays with different transmission intervals is different, that is, adjacent transmissions in time (and the transmission interval is 1), the velocity measurement range of overlapping arrays with
  • the overlapping arrays with a transmission interval of 1 can be U times the speed at which a target is obtained by a MIMO radar with a transmission period of U, and there are U values for the aliasing coefficient.
  • the overlapped array with a transmission interval of N ii can be U/N ii times the speed of the target obtained by a MIMO radar with a transmission period of U, and the value of the aliasing coefficient corresponding to the overlapped array with a transmission interval of N ii is U/N ii . .
  • the aliasing coefficient can be used as 1, 2, ..., U/N ii to specifically indicate the multiples of aliasing 0, 1, ..., U/N ii -1, where 0 means no aliasing.
  • the positive and negative relationship of the speed of the vehicle environment can be converted after multiple sets of N ii , and it is also converted here. This application only takes the post-conversion of multiple groups of N ii as an example for description.
  • the overlapped array with a transmission interval of N 1 can be used for 1, 2, ..., U/N 1 aliasing coefficient aliasing range of 0, 1, ..., U/(N 1 -1) aliasing ,
  • the range of the aliasing coefficient corresponding to the overlapping array with the transmission interval of N 2 is 0,1,...,U/(N 2 -1).
  • the processing unit determines the first set of aliasing coefficients according to the first aliasing coefficient range, the first aliasing coefficient and N 1 , and determines the second aliasing according to the second aliasing coefficient range, the second aliasing coefficient and N 2 Coefficient collection.
  • the first set of aliasing coefficients includes possible aliasing coefficients that convert the first aliasing coefficient to a third range of aliasing coefficients
  • the second set of aliasing coefficients includes converting the second aliasing coefficients to a third range of aliasing coefficients
  • the possible aliasing coefficient of, the third aliasing coefficient range is the aliasing coefficient range corresponding to the overlapping array with a transmission interval of 1.
  • the aliasing coefficients corresponding to the overlapping elements of different transmission intervals There is a certain conversion relationship. In order to reduce the influence of noise on the overlapping arrays, the aliasing coefficients corresponding to the overlapping arrays with different transmission intervals cannot be directly added for average or weighted average.
  • the method for converting the aliasing coefficients corresponding to the overlapping arrays with the transmission interval of N ii to the aliasing coefficient range corresponding to the overlapping arrays with the transmission interval of 1 is as follows:
  • N ii represents the transmission interval
  • Is the aliasing coefficient corresponding to the overlapping array with the transmission interval of N ii
  • k is the aliasing coefficient after conversion of the aliasing coefficient corresponding to the overlapping array with the transmission interval of N ii .
  • N ii >1, j has multiple values. Therefore, multiple values of k are also called aliasing
  • the coefficient set is the set of aliasing coefficients corresponding to the overlapping arrays with a transmission interval of N ii converted to the aliasing coefficients corresponding to the overlapping arrays with a transmission interval of 1.
  • the processing unit determines the third aliasing coefficient and the fourth aliasing coefficient according to the first set of aliasing coefficients and the second set of aliasing coefficients, where the third aliasing coefficient is an aliasing coefficient in the first set of aliasing coefficients ,
  • the fourth aliasing coefficient is an aliasing coefficient in the second set of aliasing coefficients.
  • the difference between the third aliasing coefficient and the fourth aliasing coefficient is the smallest value of the difference between any one of the aliasing coefficients in the first set of aliasing coefficients and any one of the aliasing coefficients in the second set of aliasing coefficients value.
  • processing unit processes the third aliasing coefficient and the fourth aliasing coefficient:
  • the processing unit calculates the average value of the third aliasing coefficient and the fourth aliasing coefficient.
  • the processing unit calculates a weighted average value of the third aliasing coefficient and the fourth aliasing coefficient.
  • the weights corresponding to the third aliasing coefficient and the fourth aliasing coefficient may be determined according to the number of overlapping elements in different transmission intervals or the signal-to-noise ratio on the channel.
  • target 1 as an example below, the specification determines the conversion process of aliasing coefficients corresponding to overlapping arrays of different emission intervals corresponding to target 1.
  • the aliasing coefficient is the aliasing coefficient corresponding to the overlapping array with a transmission interval of 1, so no conversion is required.
  • the conversion can be carried out by a similar method.
  • target 1 the specification determines the conversion process of aliasing coefficients corresponding to overlapping arrays of different emission intervals corresponding to target 1.
  • the aliasing in the range of the aliasing coefficients corresponding to the overlapping arrays with the transmission interval of 1 is obtained. Coefficient, and realizes that the speed of the first target after the aliasing is restored to the maximum speed range determined by Tc.
  • the speed can be defined as positive or negative
  • the aliasing coefficient range is [-U/2,U/2]
  • the aliasing coefficient range is [ -U/2, U/2).
  • dopplerInd amb represents the aliased Doppler identification V ind of the first target detected on the total RD image
  • N doppler represents the Doppler dimension of the RD image.
  • i represents the aliasing coefficient obtained by the first target through the overlapping arrays of multiple transmission intervals, for example, i is the three different transmissions according to Example 1.
  • the processing unit obtains the speed of the first target according to the obtained dopplerInd umamb and the speed resolution. It is understandable that N doppler is greater than or equal to N slow and the value in chirp that is greater than N slow , and zero padding is usually used.
  • an embodiment of the present application also provides a radar device 800.
  • the radar device is a MIMO radar.
  • the MIMO radar includes a transmitter 801, a receiver 802, and a processing unit 803.
  • the transmitter includes N Tx transmitting antennas.
  • the device includes N Rx receiving antennas, where N Tx and N Rx are both positive integers greater than or equal to 2, and the radar device 800 is used to perform the above-mentioned method as shown in FIG. 4.
  • the speed of solving the target according to the aliasing coefficients corresponding to the overlapping arrays of multiple transmission intervals can effectively reduce the aliasing corresponding to the overlapping arrays that are greatly affected by noise.
  • the influence of the coefficient on the velocity solution which improves the accuracy of the target velocity solution.
  • the above method will not cause the loss of the virtual antenna aperture.
  • the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the embodiments of the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the embodiments of the present application may adopt the form of computer program products implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.
  • computer-usable storage media including but not limited to disk storage, CD-ROM, optical storage, etc.
  • These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing equipment to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing equipment are generated It is a device that realizes the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.
  • These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing equipment to work in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction device.
  • the device implements the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.
  • These computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operation steps are executed on the computer or other programmable equipment to produce computer-implemented processing, so as to execute on the computer or other programmable equipment.
  • the instructions provide steps for implementing the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.

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Abstract

一种雷达信号发射和接收方法及雷达，其中，该接收方法包括：接收发射器发送的测量帧经至少一个目标反射后形成的回波信号（420），测量帧包括U*Nslow个chirp信号，其中，NTx个发射天线与NRx个接收天线形成的虚拟接收阵列包括发射间隔为N1的重叠阵子和发射间隔为N2的重叠阵子。根据回波信号确定第一混叠系数和第二混叠系数（430），第一混叠系数为第一目标对应的发射间隔为N1的重叠阵子对应的混叠系数，第二混叠系数为第一目标对应的发射间隔为N2的重叠阵子对应的混叠系数，根据第一混叠系数和第二混叠系数确定第一目标的速度（440）。采用该方法能够减轻重叠阵子受到的噪声影响，提高目标速度的求解准确度。

Description

一种雷达信号发射和接收方法及雷达 技术领域
本申请涉及传感器技术领域，特别涉及一种雷达信号发射和接收方法及雷达。
背景技术
车载雷达是自动驾驶系统中必不可少的传感器，通过车载雷达可以为车辆提供障碍物(也可以称为目标)检测。具体地，车载雷达可以发送连续调频波(frequency modulated continuous wave，FMCW)，通过探测障碍物的反射回波测量障碍物的距离，速度，方位角。
近年来，车载雷达技术不断演进，车载雷达的性能不断提高，具体可以体现在以下几个方面：频段从24GHz逐渐演进到77GHz/79GHz，从而通过更大的扫描带宽获得更高的距离分辨率；波形上从啁啾(chirp)扫描周期为几个ms级，降低到μs级，使得测量距离和测量速度解耦，降低虚假目标的概率，也可以有效避免直流附近的非理想特性；通道数由单发射多接收(single input multiple output，SIMO)的模式，演进到多发射多接收(multiple input multiple output，MIMO)的模式，并且天线规模不断扩大，使得虚拟天线口径扩大，从而提高角度分辨率，可以满足实现自动驾驶对目标更高的空间分辨率的需求。
目前在MIMO雷达中，多个天线可以采用时分复用(time division multiplexing，TDM)的方式发送chirp信号，以达到扩展虚拟天线口径的作用。但是TDM MIMO雷达存在最大测速范围下降的问题。通常，雷达的最大测速范围可以表示为±V max＝λ/(4*T)，其中，λ为调制频率的波长，T为同一根天线重复发送的周期。假设单个天线发送一个chirp的持续时间为T SIMO(可以记作一个时隙)。那么，在TDM MIMO雷达中，采用时分的方式发送N Tx个chirp信号至少需要N Tx个时隙，即N Tx个天线采用时分复用的方式发送N Tx个chirp的持续时间T MIMO＝N Tx*T SIMO。在相同的单个天线发送一个chirp的持续时间的条件下，N Tx个天线发射的最大测速范围V max_MIMO与单个天线发射的测速区间V max_SIMO的关系如下：V max_SIMO＝N Tx*V max_MIMO。通过上述公式可以看出，在TDM MIMO雷达中，由于发射天线的数目增多，导致最大测速范围与SIMO雷达相比下降。而且发射天线的数量N Tx越多，最大测速范围下降越严重。在最大测速范围下降的情况下，在计算目标的速度时更易发生速度混叠的情况。此外，由于TDM MIMO雷达中速度和角度的测量耦合，使得速度的混叠影响角度的求解，达不到预期的提高目标的空间分辨率的目的。
为了解决上述问题，现有技术中“J.Bechter,F.Roos,C.Waldschmidt,"Compensation of Motion-Induced Phase Errors in TDM MIMO Radars",IEEE Microwave and Wireless Components Letters,vol.27,no.12,pp.1164-1166,Dec.2017”提供了一种利用相邻发射天线形成的虚拟接收阵子中位置相同的阵子的相位差求解速度的方法。其中，虚拟接收阵子中位置相同的阵子又可称为重叠阵子(Overlapping Element)。但是，该方法存在以下问题：由于重叠阵子的数目受制于天线布阵，设计中为了减少对虚拟天线口径的损失，重叠阵子的数目一般较少。加上必须利用相邻发射天线形成的重叠阵子，进一步限制了可以利用的重叠阵子的数目，使得重叠阵子的相位差容易受到噪声影响，从而影响目标的速度的正确求解。
发明内容
本申请实施例提供一种雷达信号发射和接收方法及雷达，用以解决重叠阵子的相位差容易受到噪声影响，进而导致影响目标的速度的正确求解的问题。
第一方面，本申请提供一种雷达信号发射方法，应用于MIMO雷达，所述MIMO雷达包括发射器和接收器，所述发射器包括N Tx个发射天线，所述接收器包括N Rx个接收天线，其中，N Tx和N Rx均为大于等于2的正整数，所述方法包括：确定测量帧的配置信息，其中，所述测量帧的配置信息指示所述N Tx个发射天线的预设发射顺序、每个chirp信号的发射持续时间T c和所述N Tx个发射天线按照所述预设发射顺序重复发射的次数N slow；根据所述测量帧的配置信息发送所述测量帧，所述测量帧包括U*N slow个chirp信号，其中，所述U*N slow个chirp信号包括N slow组chirp信号，每组chirp信号包括U个chirp信号，所述U个chirp信号是所述N Tx个发射天线按照所述预设发射顺序在U个时隙分别发射的，每个chirp信号的发射持续时间T c记作一个时隙；所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 1的重叠阵子和发射间隔为N 2的重叠阵子，N 1≠N 2，N 1为正整数，N 2为正整数，U≥N Tx。
采用本申请实施例提供的测量帧的设计，通过N Tx个发射天线的预设发射顺序可以实现构造多种发射间隔的重叠阵子以及提高重叠阵子的数目。相较于现有技术中较少的重叠阵子数目和单一发射间隔的重叠阵子，当重叠阵子的相位差受到噪声影响较大时，将直接影响目标的速度的正确求解。而由于本申请实施例中构造了多种发射间隔的重叠阵子且重叠阵子的数目较多，即使其中部分重叠阵子的相位差受噪声影响较大，可以通过对多种发射间隔的多个重叠阵子的相位差进行处理，实现有效减轻受噪声影响较大的重叠阵子的相位差对速度求解带来的影响，进而提升目标速度求解的准确性。
在一种可能的设计中，针对每组chirp信号，发射天线m1在所述U个时隙中的时隙u 1发射chirp信号，发射天线m1和接收天线n1形成的虚拟接收天线阵子的位置为d m1n1，发射天线m1’在所述U个时隙中的时隙u 1’发射chirp信号，发射天线m1’和接收天线n1’形成的虚拟接收天线阵子的位置为d m1’n1’，发射天线m2在所述U个时隙中的时隙u 2发射chirp信号，发射天线m2和接收天线n2形成的虚拟接收天线阵子的位置为d m2n2，发射天线m2’在所述U个时隙中的时隙u 2’发射chirp信号，发射天线m2’和接收天线n2’形成的虚拟接收天线阵子的位置为d m2’n2’，所述发射间隔为N 1的重叠阵子满足d m1n1＝d m1’n1’，所述发射间隔为N 2的重叠阵子满足d m2n2＝d m2’n2’；其中，|u 1-u 1’|＝N 1，|u 2-u 2’|＝N 2；m1、n1、m1’、n1’、m2、n2、m2’、n2’均为大于等于0的整数，u 1、u 1’、u 2、u 2’均为大于等于0的整数。
在一种可能的设计中，所述N Tx个发射天线中存在至少一个发射天线在所述U个时隙中发射了2次chirp信号。
采用上述设计，可以实现提高重叠阵子的数目。
在一种可能的设计中，所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 3的重叠阵子，N 2≠N 2≠N 3，N 3为正整数。
采用上述设计，通过设计N Tx个发射天线的预设发射顺序可以实现构造多种发射间隔的重叠阵子以及提高重叠阵子的数目。
在一种可能的设计中，N 1和N 2的取值由天线布阵和所述预设发射顺序确定。
可以理解的，由于发射间隔的取值越小，则对应的测速范围越大，可以实现较少倍数 的混叠，因此，N 1和N 2的取值一般较小。
第二方面，本申请提供一种雷达信号接收方法，应用于MIMO雷达，所述MIMO雷达包括发射器和接收器，所述发射器包括N Tx个发射天线，所述接收器包括N Rx个接收天线，其中，N Tx和N Rx均为大于等于2的正整数，所述方法包括：接收测量帧经至少一个目标反射后形成的回波信号，所述测量帧包括U*N slow个chirp信号，其中，所述U*N slow个chirp信号包括N slow组chirp信号，每组chirp信号包括U个chirp信号，所述U个chirp信号是所述N Tx个发射天线按照预设发射顺序在U个时隙分别发射的，每个chirp信号的发射持续时间T c记作一个时隙；所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 1的重叠阵子和发射间隔为N 2的重叠阵子，N 1≠N 2，N 1为正整数，N 2为正整数，U≥N Tx；根据所述回波信号确定第一混叠系数和第二混叠系数；其中，所述第一混叠系数为第一目标对应的发射间隔为N 1的重叠阵子对应的混叠系数，所述第二混叠系数为所述第一目标对应的发射间隔为N 2的重叠阵子对应的混叠系数，所述第一目标为所述至少一个目标中的任意一个目标；根据第一混叠系数和第二混叠系数确定所述第一目标的速度。
相较于现有技术中较少的重叠阵子数目和单一发射间隔的重叠阵子，当重叠阵子的相位差受到噪声影响较大时，将直接影响目标的速度的正确求解。采用本申请实施例提供的方法，在针对每个目标的速度进行求解时，可以根据多种发射间隔的重叠阵子以及较多的重叠阵子的数目，计算多种发射间隔的重叠阵子分别对应的混叠系数，即使上述重叠阵子中的部分重叠阵子的相位差受噪声影响较大，导致相应的混叠系数的求解不准确，但是根据多种发射间隔的重叠阵子分别对应的混叠系数求解目标的速度，能够有效减轻受噪声影响较大的重叠阵子对应的混叠系数对速度求解带来的影响，提升目标速度求解的准确性。此外，采用上述方法，不会造成虚拟天线口径的损失。
在一种可能的设计中，针对每组chirp信号，发射天线m1在所述U个时隙中的时隙u 1发射chirp信号，发射天线m1和接收天线n1形成的虚拟接收天线阵子的位置为d m1n1，发射天线m1’在所述U个时隙中的时隙u 1’发射chirp信号，发射天线m1’和接收天线n1’形成的虚拟接收天线阵子的位置为d m1’n1’，发射天线m2在所述U个时隙中的时隙u 2发射chirp信号，发射天线m2和接收天线n2形成的虚拟接收天线阵子的位置为d m2n2，发射天线m2’在所述U个时隙中的时隙u 2’发射chirp信号，发射天线m2’和接收天线n2’形成的虚拟接收天线阵子的位置为d m2’n2’，所述发射间隔为N 1的重叠阵子满足d m1n1＝d m1’n1’，所述发射间隔为N 2的重叠阵子满足d m2n2＝d m2’n2’；其中，|u 1-u 1’|＝N 1，|u 2-u 2’|＝N 2；m1、n1、m1’、n1’、m2、n2、m2’、n2’均为大于等于0的整数，u 1、u 1’、u 2、u 2’均为大于等于0的整数。
在一种可能的设计中，根据第一混叠系数和第二混叠系数确定所述第一目标的速度，可以采用以下设计：根据N 1确定第一混叠系数范围，以及根据N 2确定第二混叠系数范围；根据所述第一混叠系数范围、所述第一混叠系数和N 1确定第一混叠系数集合，以及根据所述第二混叠系数范围、所述第二混叠系数和N 2确定第二混叠系数集合；其中，所述第一混叠系数集合包括将所述第一混叠系数折算至第三混叠系数范围的可能混叠系数，所述第二混叠系数集合包括将所述第二混叠系数折算至所述第三混叠系数范围的可能混叠系数，所述第三混叠系数范围为发射间隔为1的重叠阵子对应的混叠系数范围；根据所述第一混叠系数集合和所述第二混叠系数集合确定第三混叠系数和第四混叠系数，所述第三混叠系数 为所述第一混叠系数集合中的一个混叠系数，所述第四混叠系数为所述第二混叠系数集合中的一个混叠系数；根据所述第三混叠系数和所述第四混叠系数确定所述第一目标的速度。
采用上述设计可以实现将不同发射间隔的重叠阵子分别对应的混叠系数折算至发射间隔为1的重叠阵子对应的混叠系数范围，进而可以恢复到Tc确定的最大测速范围。
在一种可能的设计中，所述第三混叠系数和所述第四混叠系数的差值为所述第一混叠系数集合中的任意一个混叠系数与所述第二混叠系数集合中的任意一个混叠系数的差值中的最小值。
采用上述设计可以实现从第一混叠系数集合中正确选取第三混叠系数，从第二混叠系数集合中正确选取第四混叠系数。
在一种可能的设计中，根据所述第三混叠系数和所述第四混叠系数确定所述第一目标的速度可以采用以下设计：根据所述第三混叠系数和所述第四混叠系数的平均值确定所述第一目标的速度；或者，根据所述第三混叠系数和所述第四混叠系数的加权平均值确定所述第一目标的速度。
采用上述设计，通过对多个混叠系数求平均或加权平均，可以有效减轻重叠阵子的相位差受到的噪声影响，进而有助于目标速度的正确求解。
在一种可能的设计中，N 1和N 2互质。
通过N 1和N 2互质可以保证通过第一混叠系数集合和第二混叠系数集合确定的第三混叠系数和第四混叠系数具有唯一性。
在一种可能的设计中，所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 3的重叠阵子，N 2≠N 2≠N 3，N 3为正整数。
采用上述设计，可以实现构造多种发射间隔的重叠阵子以及提高重叠阵子的数目。
第三方面，本申请实施例还提供一种雷达设备，所述设备包括发射器、接收器和处理单元，所述发射器包括N Tx个发射天线，所述接收器包括N Rx个接收天线，其中，N Tx和N Rx均为大于等于2的正整数，其中：
所述处理单元，用于确定测量帧的配置信息，其中，所述测量帧的配置信息指示所述N Tx个发射天线的预设发射顺序、每个啁啾chirp信号的发射持续时间T c和所述N Tx个发射天线按照所述预设发射顺序重复发射的次数N slow；
所述发射器，用于根据所述测量帧的配置信息发送所述测量帧，所述测量帧包括U*N slow个chirp信号，其中，所述U*N slow个chirp信号包括N slow组chirp信号，每组chirp信号包括U个chirp信号，所述U个chirp信号是所述N Tx个发射天线按照所述预设发射顺序在U个时隙分别发射的，每个chirp信号的发射持续时间T c记作一个时隙；所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 1的重叠阵子和发射间隔为N 2的重叠阵子，N 1≠N 2，N 1为正整数，N 2为正整数，U≥N Tx。
在一种可能的设计中，针对每组chirp信号，发射天线m1在所述U个时隙中的时隙u 1发射chirp信号，发射天线m1和接收天线n1形成的虚拟接收天线阵子的位置为d m1n1，发射天线m1’在所述U个时隙中的时隙u 1’发射chirp信号，发射天线m1’和接收天线n1’形成的虚拟接收天线阵子的位置为d m1’n1’，发射天线m2在所述U个时隙中的时隙u 2发射chirp信号，发射天线m2和接收天线n2形成的虚拟接收天线阵子的位置为d m2n2，发射天线m2’在所述U个时隙中的时隙u 2’发射chirp信号，发射天线m2’和接收天线n2’形成的虚拟接收天线阵子的位置为d m2’n2’，所述发射间隔为N 1的重叠阵子满足d m1n1＝d m1’n1’，所述 发射间隔为N 2的重叠阵子满足d m2n2＝d m2’n2’；其中，|u 1-u 1’|＝N 1，|u 2-u 2’|＝N 2；m1、n1、m1’、n1’、m2、n2、m2’、n2’均为大于等于0的整数，u 1、u 1’、u 2、u 2’均为大于等于0的整数。
在一种可能的设计中，所述N Tx个发射天线中存在至少一个发射天线在所述U个时隙中发射了2次chirp信号。
在一种可能的设计中，所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 3的重叠阵子，N 2≠N 2≠N 3，N 3为正整数。
具体可以参阅第一方面中描述的技术效果，重复之处不再赘述。
第四方面，本申请实施例提供一种雷达设备，所述设备为MIMO雷达，所述MIMO雷达包括发射器、接收器和处理单元，所述发射器包括N Tx个发射天线，所述接收器包括N Rx个接收天线，其中，N Tx和N Rx均为大于等于2的正整数，其中：
所述接收器，用于接收测量帧经至少一个目标反射后形成的回波信号，所述测量帧包括U*N slow个chirp信号，其中，所述U*N slow个chirp信号包括N slow组chirp信号，每组chirp信号包括U个chirp信号，所述U个chirp信号是所述N Tx个发射天线按照预设发射顺序在U个时隙分别发射的，每个chirp信号的发射持续时间T c记作一个时隙；所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 1的重叠阵子和发射间隔为N 2的重叠阵子，N 1≠N 2，N 1为正整数，N 2为正整数，U≥N Tx；
所述处理单元，用于根据所述回波信号确定第一混叠系数和第二混叠系数；其中，所述第一混叠系数为第一目标对应的发射间隔为N 1的重叠阵子对应的混叠系数，所述第二混叠系数为所述第一目标对应的发射间隔为N 2的重叠阵子对应的混叠系数，所述第一目标为所述至少一个目标中的任意一个目标；根据第一混叠系数和第二混叠系数确定所述第一目标的速度。
在一种可能的设计中，针对每组chirp信号，发射天线m1在所述U个时隙中的时隙u 1发射chirp信号，发射天线m1和接收天线n1形成的虚拟接收天线阵子的位置为d m1n1，发射天线m1’在所述U个时隙中的时隙u 1’发射chirp信号，发射天线m1’和接收天线n1’形成的虚拟接收天线阵子的位置为d m1’n1’，发射天线m2在所述U个时隙中的时隙u 2发射chirp信号，发射天线m2和接收天线n2形成的虚拟接收天线阵子的位置为d m2n2，发射天线m2’在所述U个时隙中的时隙u 2’发射chirp信号，发射天线m2’和接收天线n2’形成的虚拟接收天线阵子的位置为d m2’n2’，所述发射间隔为N 1的重叠阵子满足d m1n1＝d m1’n1’，所述发射间隔为N 2的重叠阵子满足d m2n2＝d m2’n2’；其中，|u 1-u 1’|＝N 1，|u 2-u 2’|＝N 2；m1、n1、m1’、n1’、m2、n2、m2’、n2’均为大于等于0的整数，u 1、u 1’、u 2、u 2’均为大于等于0的整数。
在一种可能的设计中，所述处理单元，用于：根据N 1确定第一混叠系数范围，以及根据N 2确定第二混叠系数范围；根据所述第一混叠系数范围、所述第一混叠系数和N 1确定第一混叠系数集合，以及根据所述第二混叠系数范围、所述第二混叠系数和N 2确定第二混叠系数集合；其中，所述第一混叠系数集合包括将所述第一混叠系数折算至第三混叠系数范围的可能混叠系数，所述第二混叠系数集合包括将所述第二混叠系数折算至所述第三混叠系数范围的可能混叠系数，所述第三混叠系数范围为发射间隔为1的重叠阵子对应的混叠系数范围；根据所述第一混叠系数集合和所述第二混叠系数集合确定第三混叠系数和第四混叠系数，所述第三混叠系数为所述第一混叠系数集合中的一个混叠系数，所述第四混 叠系数为所述第二混叠系数集合中的一个混叠系数；根据所述第三混叠系数和所述第四混叠系数确定所述第一目标的速度。
在一种可能的设计中，所述第三混叠系数和所述第四混叠系数的差值为所述第一混叠系数集合中的任意一个混叠系数与所述第二混叠系数集合中的任意一个混叠系数的差值中的最小值。
在一种可能的设计中，所述处理单元，用于：根据所述第三混叠系数和所述第四混叠系数的平均值确定所述第一目标的速度；或者，根据所述第三混叠系数和所述第四混叠系数的加权平均值确定所述第一目标的速度。
在一种可能的设计中，所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 3的重叠阵子，N 2≠N 2≠N 3，N 3为正整数。
具体可以参阅第二方面中描述的技术效果，重复之处不再赘述。
附图说明
图1为本申请MIMO雷达系统的结构示意图；
图2为本申请中具有自动驾驶功能的车辆200的功能框图；
图3为本申请中3个发射天线4个接收天线的水平阵形成2对重叠阵子的示意图之一；
图4为本申请中一种雷达信号发射方法的概述流程图；
图5为本申请中3个发射天线4个接收天线的水平阵形成2对重叠阵子的示意图之二；
图6(a)～图6(c)为本申请中一种的可能的发射天线的发射顺序示意图；
图7为本申请中不同发射间隔的重叠阵子分别对应的混叠系数范围的示意图；
图8为本申请中一个雷达的结构示意图。
具体实施方式
下面结合附图，对本申请的实施例进行描述。
本申请实施例中，如图1所示，MIMO雷达系统可以包括天线阵列101、微波集成电路(monolithic microwave integrated circuit，MMIC)102和处理单元103。天线阵列101可以包括多个发射天线和多个接收天线。
其中，微波集成电路102用于产生雷达信号，进而通过天线阵列101将雷达信号发出。雷达信号包括多个啁啾信号。雷达信号发出后，经一个或多个目标反射后形成回波信号，回波信号被接收天线接收。微波集成电路102还用于对天线阵列101接收到的回波信号进行变换和采样等处理，并将处理后的回波信号传输至处理单元103。
其中，处理单元103用于对回波信号进行快速傅里叶变换(Fast Fourier Transformation，FFT)、信号处理等操作，从而根据接收到的回波信号确定目标的距离、速度、方位角等信息。具体地，该处理单元103可以是微处理器(microcontroller unit，MCU)、中央处理器(central process unit，CPU)、数字信号处理器(digital signal processor，DSP)、现场可编程门阵列(field－programmable gate array，FPGA)、专用加速器等具有处理功能的器件。
此外，图1所示的雷达系统还可以包括电子控制单元(electronic control unit，ECU)104，用于根据处理单元103处理后得到的目标距离、速度、方位角等信息对车辆进行控制，例 如确定车辆的行使路线、控制车辆的速度等。
本申请实施例中的发射器可以由发射天线与微波集成电路102中的发射通道构成，接收器可以由接收天线与微波集成电路102中的接收通道构成。其中，发射天线和接收天线可以位于印刷电路板(print circuit board，PCB)上，发射通道和接收通道可以位于芯片内，即AOB(antenna on PCB)；或者，发射天线和接收天线可以位于芯片封装内，发射通道和接收通道可以位于芯片内，即AIP(antenna in package)。本申请实施例中对于组合形式不做具体限定。应理解，本申请实施例中对发射通道和接收通道的具体结构不做限定，只要能实现相应发射和接收功能即可。
另外由于单个微波集成电路(射频芯片)的通道规格数比较有限，系统需要的收发通道数大于单个射频芯片时，需要多个射频芯片级联。因此，整个雷达系统可能包括多个射频芯片级联，例如，发射天线阵列和接收天线阵列是多个MIMO级联得到的，通过接口连接模拟数字转换器(analog digital converter，ADC)通道输出的数据到处理单元103，例如MCU，DSP，FPGA，通用处理单元(General Process Unit，GPU)等。又例如，MMIC和DSP可以集成在一个芯片中，称为片上系统(System on chip，SOC)。又例如，MMIC和ADC，处理单元103可以集成在一个芯片中，构成SOC。另外，整车可能安装一个或多个雷达系统，并且通过车载总线和中央处理器连接。中央处理器控制一个或多个车载传感器，包括一个或多个毫米波雷达传感器。
下面对本申请实施例的应用场景进行介绍。
图1所示的MIMO雷达系统可以应用于具有自动驾驶功能的车辆。参见图2，为本申请实施例提供的具有自动驾驶功能的车辆200的功能框图。在一个实施例中，将车辆200配置为完全或部分地自动驾驶模式。例如，车辆200可以在处于自动驾驶模式中可以同时控制自身，并且可以通过人为操作来确定车辆及其周边环境的当前状态，确定周边环境中的至少一个其他车辆的可能行为，并确定该其他车辆执行可能行为的可能性相对应的置信水平，并基于所确定的信息来控制车辆200。在车辆200处于自动驾驶模式中时，可以将车辆200置为在没有和人交互的情况下操作。
车辆200可包括各种子系统，例如行进系统202、传感器系统204、控制系统206、一个或多个外围设备208以及电源210、计算机系统212和用户接口216。可选地，车辆200可包括更多或更少的子系统，并且每个子系统可包括多个元件。另外，车辆200的每个子系统和元件可以通过有线或者无线互连。
行进系统202可包括为车辆200提供动力运动的组件。在一个实施例中，行进系统202可包括引擎218、能量源219、传动装置220和车轮/轮胎221。引擎218可以是内燃引擎、电动机、空气压缩引擎或其他类型的引擎组合，例如气油发动机和电动机组成的混动引擎，内燃引擎和空气压缩引擎组成的混动引擎。引擎218将能量源219转换成机械能量。
能量源219的示例包括汽油、柴油、其他基于石油的燃料、丙烷、其他基于压缩气体的燃料、乙醇、太阳能电池板、电池和其他电力来源。能量源219也可以为车辆200的其他系统提供能量。
传动装置220可以将来自引擎218的机械动力传送到车轮221。传动装置220可包括变速箱、差速器和驱动轴。在一个实施例中，传动装置220还可以包括其他器件，比如离合器。其中，驱动轴可包括可耦合到一个或多个车轮221的一个或多个轴。
传感器系统204可包括感测关于车辆200周边的环境的信息的若干个传感器。例如， 传感器系统204可包括定位系统222(定位系统可以是全球定位系统(global positioning system，GPS)系统，也可以是北斗系统或者其他定位系统)、惯性测量单元(inertial measurement unit，IMU)224、雷达226、激光测距仪228以及相机230。传感器系统204还可包括被监视车辆200的内部系统的传感器(例如，车内空气质量监测器、燃油量表、机油温度表等)。来自这些传感器中的一个或多个的传感器数据可用于检测对象及其相应特性(位置、形状、方向、速度等)。这种检测和识别是车辆200的安全操作的关键功能。
定位系统222可用于估计车辆200的地理位置。IMU 224用于基于惯性加速度来感测车辆200的位置和朝向变化。在一个实施例中，IMU 224可以是加速度计和陀螺仪的组合。
雷达226可利用无线电信号来感测车辆200的周边环境内的目标。在一些实施例中，除了感测目标以外，雷达226还可用于感测目标的速度和/或前进方向。在一个具体示例中，雷达226可以采用图1所示的MIMO雷达系统实现。
激光测距仪228可利用激光来感测车辆100所位于的环境中的目标。在一些实施例中，激光测距仪228可包括一个或多个激光源、激光扫描器以及一个或多个检测器，以及其他系统组件。
相机230可用于捕捉车辆200的周边环境的多个图像。相机230可以是静态相机或视频相机。
控制系统206为控制车辆200及其组件的操作。控制系统206可包括各种元件，其中包括转向系统232、油门234、制动单元236、传感器融合算法238、计算机视觉系统240、路线控制系统242以及障碍物避免系统244。
转向系统232可操作来调整车辆200的前进方向。例如在一个实施例中可以为方向盘系统。
油门234用于控制引擎218的操作速度并进而控制车辆200的速度。
制动单元236用于控制车辆200减速。制动单元236可使用摩擦力来减慢车轮221。在其他实施例中，制动单元236可将车轮221的动能转换为电流。制动单元236也可采取其他形式来减慢车轮221转速从而控制车辆200的速度。
计算机视觉系统240可以操作来处理和分析由相机230捕捉的图像以便识别车辆200周边环境中的目标和/或特征。所述目标和/或特征可包括交通信号、道路边界和障碍物。计算机视觉系统240可使用目标识别算法、运动中恢复结构(structure from motion，SFM)算法、视频跟踪和其他计算机视觉技术。在一些实施例中，计算机视觉系统240可以用于为环境绘制地图、跟踪目标、估计目标的速度等等。
路线控制系统242用于确定车辆200的行驶路线。在一些实施例中，路线控制系统142可结合来自传感器238、GPS 222和一个或多个预定地图的数据以为车辆200确定行驶路线。
障碍物避免系统244用于识别、评估和避免或者以其他方式越过车辆200的环境中的潜在障碍物。
当然，在一个实例中，控制系统206可以增加或替换地包括除了所示出和描述的那些以外的组件。或者也可以减少一部分上述示出的组件。
车辆200通过外围设备208与外部传感器、其他车辆、其他计算机系统或用户之间进行交互。外围设备208可包括无线通信系统246、车载电脑248、麦克风250和/或扬声器252。
在一些实施例中，外围设备208提供车辆200的用户与用户接口216交互的手段。例如，车载电脑248可向车辆200的用户提供信息。用户接口216还可操作车载电脑248来接收用户的输入。车载电脑248可以通过触摸屏进行操作。在其他情况中，外围设备208可提供用于车辆200与位于车内的其它设备通信的手段。例如，麦克风250可从车辆200的用户接收音频(例如，语音命令或其他音频输入)。类似地，扬声器252可向车辆200的用户输出音频。
无线通信系统246可以直接地或者经由通信网络来与一个或多个设备无线通信。例如，无线通信系统246可使用3G蜂窝通信，例如码分多址(code division multiple access，CDMA)、EVD0、全球移动通信系统(global system for mobile communications，GSM)/通用分组无线服务技术(general packet radio service，GPRS)，或者4G蜂窝通信，例如长期演进(long term evolution，LTE)，或者5G蜂窝通信。无线通信系统246可利用WiFi与无线局域网(wireless local area network，WLAN)通信。在一些实施例中，无线通信系统246可利用红外链路、蓝牙或ZigBee与设备直接通信。其他无线协议，例如各种车辆通信系统，例如，无线通信系统246可包括一个或多个专用短程通信(dedicated short range communications，DSRC)设备，这些设备可包括车辆和/或路边台站之间的公共和/或私有数据通信。
电源210可向车辆200的各种组件提供电力。在一个实施例中，电源210可以为可再充电锂离子或铅酸电池。这种电池的一个或多个电池组可被配置为电源为车辆200的各种组件提供电力。在一些实施例中，电源210和能量源219可一起实现，例如一些全电动车中那样。
车辆200的部分或所有功能受计算机系统212控制。计算机系统212可包括至少一个处理器223，处理器223执行存储在例如存储器224这样的非暂态计算机可读介质中的指令225。计算机系统212还可以是采用分布式方式控制车辆200的个体组件或子系统的多个计算设备。
处理器223可以是任何常规的处理器，诸如商业可获得的中央处理器(central processing unit，CPU)。替选地，该处理器可以是诸如专用集成电路(application specific integrated circuits,ASIC)或其它基于硬件的处理器的专用设备。尽管图2功能性地图示了处理器、存储器、和在相同块中的计算机210的其它元件，但是本领域的普通技术人员应该理解该处理器、计算机、或存储器实际上可以包括可以或者可以不存储在相同的物理外壳内的多个处理器、计算机、或存储器。例如，存储器可以是硬盘驱动器或位于不同于计算机210的外壳内的其它存储介质。因此，对处理器或计算机的引用将被理解为包括对可以或者可以不并行操作的处理器或计算机或存储器的集合的引用。不同于使用单一的处理器来执行此处所描述的步骤，诸如转向组件和减速组件的一些组件每个都可以具有其自己的处理器，所述处理器只执行与特定于组件的功能相关的计算。
在此处所描述的各个方面中，处理器可以位于远离该车辆并且与该车辆进行无线通信。在其它方面中，此处所描述的过程中的一些在布置于车辆内的处理器上执行而其它则由远程处理器执行，包括采取执行单一操纵的必要步骤。
在一些实施例中，存储器224可包含指令225(例如，程序逻辑)，指令225可被处理器223执行来执行车辆200的各种功能，包括以上描述的那些功能。存储器214也可包含额外的指令，包括向行进系统202、传感器系统204、控制系统206和外围设备208中的一个或多个发送数据、从其接收数据、与其交互和/或对其进行控制的指令。
除了指令225以外，存储器224还可存储数据，例如道路地图、路线信息，车辆的位置、方向、速度以及其它这样的车辆数据，以及其他信息。这种信息可在车辆200在自主、半自主和/或手动模式中操作期间被车辆200和计算机系统212使用。
用户接口216，用于向车辆200的用户提供信息或从其接收信息。可选地，用户接口216可包括在外围设备208的集合内的一个或多个输入/输出设备，例如无线通信系统246、车载电脑248、麦克风250和扬声器252。
计算机系统212可基于从各种子系统(例如，行进系统202、传感器系统204和控制系统206)以及从用户接口216接收的输入来控制车辆200的功能。例如，计算机系统212可利用来自控制系统206的输入以便控制转向单元232来避免由传感器系统204和障碍物避免系统244检测到的障碍物。在一些实施例中，计算机系统212可操作来对车辆200及其子系统的许多方面提供控制。
可选地，上述这些组件中的一个或多个可与车辆200分开安装或关联。例如，存储器224可以部分或完全地与车辆200分开存在。上述组件可以按有线和/或无线方式来通信地耦合在一起。
可选地，上述组件只是一个示例，实际应用中，上述各个模块中的组件有可能根据实际需要增添或者删除，图2不应理解为对本申请实施例的限制。
在道路行进的自动驾驶汽车，如上面的车辆200，可以识别其周围环境内的目标以确定对当前速度的调整。所述目标可以是其它车辆、交通控制设备、或者其它类型的目标。在一些示例中，可以独立地考虑每个识别的目标，并且基于目标的各自的特性，诸如它的当前速度、加速度、与车辆的间距等，可以用来确定自动驾驶汽车所要调整的速度。
可选地，自动驾驶汽车车辆200或者与自动驾驶车辆200相关联的计算设备(如图2的计算机系统212、计算机视觉系统240、存储器224)可以基于所识别的目标的特性和周围环境的状态(例如，交通、雨、道路上的冰等等)来预测所述识别的目标的行为。可选地，每一个所识别的目标都依赖于彼此的行为，因此还可以将所识别的所有目标全部一起考虑来预测单个识别的目标的行为。车辆200能够基于预测的所述识别的目标的行为来调整它的速度。换句话说，自动驾驶汽车能够基于所预测的目标的行为来确定车辆将需要调整到(例如，加速、减速、或者停止)什么稳定状态。在这个过程中，也可以考虑其它因素来确定车辆200的速度，诸如，车辆200在行驶的道路中的横向位置、道路的曲率、静态和动态目标的接近度等等。
除了提供调整自动驾驶汽车的速度的指令之外，计算设备还可以提供修改车辆200的转向角的指令，以使得自动驾驶汽车遵循给定的轨迹和/或维持与自动驾驶汽车附近的目标(例如，道路上的相邻车道中的轿车)的安全横向和纵向距离。
上述车辆200可以为轿车、卡车、摩托车、公共汽车、船、飞机、直升飞机、割草机、娱乐车、游乐场车辆、施工设备、电车、高尔夫球车、火车、和手推车等，本申请实施例不做特别的限定。
此外，同样需要说明的是，本申请实施例中所述的雷达系统可以应用于多种领域，示例性地，本申请实施例中的雷达系统包括但不限于车载雷达、路边交通雷达，无人机雷达。
需要说明的是，本申请实施例中，多个，是指两个或两个以上。另外，需要理解的是，在本申请的描述中，“第一”、“第二”等词汇，仅用于区分描述的目的，而不能理解为指示或暗示相对重要性，也不能理解为指示或暗示顺序。
基于此，本申请提供一种雷达信号发射和接收方法，该方法应用于MIMO雷达，MIMO雷达包括发射器、接收器和处理单元，发射器包括N Tx个发射天线，接收器包括N Rx个接收天线，其中，N Tx和N Rx均为大于等于2的正整数。应理解的是，MIMO雷达的具体结构可以如图1所示，也可以不限于图1的具体结构，本申请对此不作限定。
该方法包括：
步骤400：处理单元确定测量帧的配置信息，其中，测量帧的配置信息指示N Tx个发射天线的预设发射顺序、每个chirp信号的发射持续时间T c和N Tx个发射天线按照预设发射顺序重复发射的次数N slow。
示例性地，测量帧的配置信息包括N Tx个发射天线的预设发射顺序、T c和N slow，或者，N Tx个发射天线的预设发射顺序、U*T c和N slow。应理解的是，本申请对测量帧的配置信息的具体形式不作限定。
处理单元在确定测量帧的配置信息后，并通过接口将测量帧的配置信息发送至单片或多片MMIC，单片或多片MMIC用于根据测量帧的配置信息使能发射器发送测量帧。
步骤410：发射器根据测量帧的配置信息发送测量帧，测量帧包括U*N slow个chirp信号，其中，U*N slow个chirp信号包括N slow组chirp信号，每组chirp信号包括U个chirp信号，U个chirp信号是N Tx个发射天线按照预设发射顺序在U个时隙分别发射的，每个chirp信号的发射持续时间T c记作一个时隙；N Tx个发射天线与N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 1的重叠阵子和发射间隔为N 2的重叠阵子，N 1≠N 2，N 1为正整数，N 2为正整数，U≥N Tx。
其中，针对每组chirp信号，发射天线m1在U个时隙中的时隙u 1发射chirp信号，发射天线m1和接收天线n1形成的虚拟接收天线阵子的位置为d m1n1，发射天线m1’在U个时隙中的时隙u 1’发射chirp信号，发射天线m1’和接收天线n1’形成的虚拟接收天线阵子的位置为d m1’n1’，发射天线m2在U个时隙中的时隙u 2发射chirp信号，发射天线m2和接收天线n2形成的虚拟接收天线阵子的位置为d m2n2，发射天线m2’在U个时隙中的时隙u 2’发射chirp信号，发射天线m2’和接收天线n2’形成的虚拟接收天线阵子的位置为d m2’n2’，发射间隔为N 1的重叠阵子满足d m1n1＝d m1’n1’，发射间隔为N 2的重叠阵子满足d m2n2＝d m2’n2’；其中，|u 1-u 1’|＝N 1，|u 2-u 2’|＝N 2；m1、n1、m1’、n1’、m2、n2、m2’、n2’均为大于等于0的整数，u 1、u 1’、u 2、u 2’均为大于等于0的整数。
其中，测量帧可以为FMCW，也可以采用其他MIMO雷达所使用的波形，例如，测量帧还可以为脉冲波形或正交频分复用(Orthogonal Frequency Division Multiplex，OFDM)等波形。
本申请对此不做限定。以下仅以FMCW为例进行说明。
在一种可能的设计中，N 1和N 2互质。示例性地，N 1＝1，N 2＝2。
在一种可能的设计中，N 1和N 2的取值由天线布阵和预设顺序确定。可以理解的，由于发射间隔的取值越小，则对应的测速范围越大，可以实现较少倍数的混叠，因此，N 1和N 2的取值一般较小。
此外，在一种可能的设计中，N Tx个发射天线与N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 3的重叠阵子，N 1≠N 2≠N 3，N 3为正整数。示例性地，N 1＝1，N 2＝2，N 3＝3。
以下对根据预设发射顺序和天线布阵确定重叠阵子的方法进行简要介绍：
1)根据预设发射顺序和天线布阵，确定发射天线和接收天线的形成的虚拟接收天线位置。
传统虚拟接收天线(Virtual Receiver antenna)：发射天线和接收天线合成得到的天线为虚拟接收天线，又可描述为发射天线和接收天线合成得到虚拟接收阵列。其中，发射天线的数量为N Tx,接收天线的数量为N Rx。发射天线Tx i的坐标位置在二维平面表示为(x i，y i),其中1≤i≤N Tx；接收天线Rx i的坐标位置在二维平面表示为(x i，y i),其中1≤j≤N Rx,那么总共可以得到N Tx*N Rx个虚拟阵子。为了方便描述由于天线发射顺序引入的发射间隔，以及相同发射天线重复发射形成的位置相同的虚拟阵子，在本申请中，按照预设发射顺序发射U个chirp信号，在时隙u中发射天线m发射chirp信号，时隙u发射的发射天线m和接收天线n形成的虚拟阵子的位置为：
d k＝d mn＝(x m，y m) u+(x n，y n) u＝(x m+x n，y m+y n) u  (公式1)
其中，d k表示按照预设发射顺序和顺序排列的N Rx个接收信号形成的虚拟天线位置。
k＝(u-1)*N Rx+n Rx，1≤k≤U*N Rx，1≤u≤U，1≤n Rx≤N Rx
发射天线m的坐标位置在二维平面表示为(x m，y m) u,其中1≤m≤N Tx，接收天线n的坐标位置在二维平面表示为(x n，y n) u,其中1≤n≤N Rx。
2)标记其中位置重复的虚拟接收阵子对(即重叠阵子)，以及形成该重叠阵子的发射时隙的间隔(即发射间隔)。
3)把相同的发射间隔的重叠阵子分成一组。在本申请中，至少存在2组发射间隔不同的重叠阵子，每组中至少包括一对重叠阵子。
值得注意的是，现有技术中仅包括发射间隔为1的重叠阵子，并且仅包括硬件形成的重叠阵子，不包括由于U>N Tx时，由于同一个发射天线的多次发射形成的重叠阵子。
这里进一步说明重叠阵子的形成的方法可以包括但不限于以下两种方式：
方式1：重叠阵子是由不同天线的部署形成。
其中，采用方式1形成的重叠阵子又可称为硬件上的重叠阵子。
通常虚拟阵列分为一维阵和二维阵。一维阵是指发射天线阵列中每个阵子垂直Y轴坐标位置相同，并且接收天线阵列中每个阵子垂直Y轴坐标位置都相同的情况，一维阵仅能获得目标的水平角度，即水平阵。二维阵是指发射天线阵列中每个阵子Y轴坐标至少有一个阵子位置和其他阵子不相同，并且接收天线阵列中每个阵子Y轴坐标有一个阵子位置和其他阵子不相同。二维阵包括一个或多个一维子阵。
这里举例说明硬件上的重叠阵子，如图3所示，3个发射天线4个接收天线(简称为3发射4接收(3T4R))一维水平阵形成2对重叠阵子的示意图。发射天线的间隔为3λ/2的水平阵,接收天线的间隔为λ/2的水平阵，其中，λ为半波长。由于收发天线阵列都是一维阵，因此，可以把发射天线阵列的位置写成X Tx＝[0，3λ/2，3λ]，接收天线阵列的位置写成X Rx＝[0，λ/2，λ，3λ/2]。
当发射天线的发射顺序为1，2，3时，U＝3，可以得到U个时隙内N Rx个接收天线上对应的虚拟接收阵子位置矩阵D，D＝[d k]，1≤k≤U*N Rx，，D＝[0,λ/2,λ,3λ/2,3λ/2,2λ,5λ/2,3λ,3λ,7λ/2,4λ,9λ/2]。3个发射天线4个接收天线形成的虚拟接收阵列中存在在3λ/2 的位置上发射间隔为1的重叠阵子和在3λ的位置上发射间隔为1的重叠阵子，即在接收侧形成两对重叠阵子，且这两对重叠阵子的发射间隔相同，且均为1。如图5所示，当发射天线的发射顺序为1，3，2时，D＝[0，λ/2，λ，3λ/2，3λ，7λ/2，4λ，9λ/2，3λ/2，2λ，5λ/2，3λ]。虚拟接收阵列中存在在3λ/2的位置上发射间隔为2的重叠阵子和在3λ的位置上发射间隔为1的重叠阵子，由此可知，当发射顺序从1，2，3变为1，3，2时，这种发射顺序的改变不会造成重叠阵子的位置发生变化，仅对发射间隔产生影响。
方式2：重叠阵子是由同一个天线占用不同发射时刻形成的。
在一种可能的设计中，N Tx个发射天线中存在至少一个发射天线在U个发射时隙中发射了2次chirp信号。
其中，采用方式1形成的重叠阵子又可称为软件上的重叠阵子，或软重叠阵子。
示例性地，如图6(a)～6(c)所示，以3T4R水平阵为例，当N Tx＝3，U＝4*3时的一种的可能的发射天线的发射顺序，那么每个天线发射了4次。该发射顺序为2-2-1-1-1-2-3-3-2-3-3-1。应理解的是，该发射顺序仅为举例，不作为本申请的限定。以下基于图6(a)～6(c)说明软重叠阵子以及相应的发射间隔。
由图6(a)可知，发射天线2连续发送两次，则在接收侧形成4对重叠阵子，且这4对重叠阵子的发射间隔相同，且均为1。同理，如图6(a)中虚线所示，在接收侧形成20对重叠阵子，即5*4＝20。
如图6(b)所示，粗线标记的1和1，在接收侧形成4对重叠阵子，且这4对重叠阵子的发射间隔相同，且均为2。同理，粗线标记的3和3，在接收侧形成4对重叠阵子，且这4对重叠阵子的发射间隔相同，且均为2。
如图6(c)所示，连接线连接的2和2，在接收侧形成4对重叠阵子，且这4对重叠阵子的发射间隔相同，且均为3。同理，连接线连接的两对3和3，在接收侧形成2*4对重叠阵子，且这8对重叠阵子的发射间隔相同，且均为3。
注意软重叠阵子不损失口径，虽然由于U>N Tx，会降低最大MIMO对应的最大测速范围，但本方法不影响每个chirp的发射持续时间Tc，因此，系统最终可以恢复到Tc确定的最大测试范围不变。可以理解的，如果结合两种方式，重叠阵子数目可以进一步增加，其中，方式1形成的重叠阵子包括：发射间隔为1的重叠阵子依次为：发射天线2和发射天线1(用2-1表示)在接收侧形成1对重叠阵子，发射天线1和发射天线(用1-2表示)2在接收侧形成1对重叠阵子，发射天线3和发射天线2(用3-2表示)在接收侧形成1对重叠阵子，发射天线2和发射天线3(用2-3表示)在接收侧形成1对重叠阵子。发射间隔为2的重叠阵子依次为：发射天线2与间隔1个的发射天线1(用2-1-1表示)在接收侧形成1对重叠阵子，发射天线1与间隔1个的发射天线2(用1-1-2表示)在接收侧形成1对重叠阵子，发射天线3与间隔1个的发射天线2(用3-3-2表示)在接收侧形成1对重叠阵子，发射天线2与间隔1个的发射天线3(用2-3-3表示)在接收侧形成1对重叠阵子。
综上，通过上述两种方式总结得到，发射间隔为1的重叠阵子包括4+20＝24对，发射间隔为2的重叠阵子包括8+4＝12对。注意，在实际工程中，如果硬件重叠阵子造成软件重叠阵子的损失，需要进一步排除重复计算的部分，本申请不做限制。
此外，根据实际需要，还可以进一步统计两种方式下发射间隔为3的重叠阵子，以及其他发射间隔的重叠阵子的数目，本申请对此不作限定。
因此，采用本申请实施例提供的测量帧的设计，通过N Tx个发射天线的预设发射顺序 可以实现构造多种发射间隔的重叠阵子以及提高重叠阵子的数目。相较于现有技术中较少的重叠阵子数目和单一发射间隔的重叠阵子，当重叠阵子的相位差受到噪声影响较大时，将直接影响目标的速度的正确求解。而由于本申请实施例中构造了多种发射间隔的重叠阵子且重叠阵子的数目较多，即使其中部分重叠阵子的相位差受噪声影响较大，可以通过对多种发射间隔的多个重叠阵子的相位差进行处理，实现有效减轻受噪声影响较大的重叠阵子的相位差对速度求解带来的影响，进而提升目标速度求解的准确性。
步骤420：接收器接收发射器发送的测量帧经一个或多个目标反射后形成的回波信号。
需要说明的是，本申请实施例中，接收器中包括N Rx个接收天线，N Rx个接收天线按照N Tx个发射天线的发射顺序，接收U个接收信号，然后根据N Tx个发射天线和N Rx个接收天线之间的位置关系以及发射天线的发射顺序，将接收到的U个接收信号转换成回波信号。
由于N slow为按照预设顺序重复发射的次数，则得到N slow个回波信号。
其中，U表示按照TDM的方式不同天线在一个重复周期内发射信号的时隙数，发射周期为U*T c，其中，在U个时隙中同一天线可以发射多次。进一步地，U个接收信号中的一个接收信号是发射的一个chirp信号经一个或多个目标反射后形成的chirp信号。
步骤430：处理单元确定第一混叠系数和第二混叠系数。
其中，第一混叠系数为第一目标对应的发射间隔为N 1的重叠阵子对应的混叠系数，第二混叠系数为第一目标对应的发射间隔为N 2的重叠阵子对应的混叠系数，第一目标为至少一个目标中的任意一个目标。
通常，单个chirp内信号称为快速啁啾(fast chirp)，可以获得目标的距离信息，多个chirp信号称为形成慢速啁啾(slow chirp)，可以获得目标的速度信息。
处理单元计算每个fast chirp对应的距离维度快速傅里叶变换，进一步地，在fast chirp fft的基础上，计算同一个距离单元(Range bin)上的不同slow chirp上的速度维快速傅里叶变换，获得U*N Rx个虚拟接收阵子的两维傅里叶变换结果。示例性地，一个虚拟接收阵子的两维傅里叶变换结果是指该虚拟接收阵子对应的距离多普勒图(Range-Doppler Map)。对于本申请实施例，可以理解是，一个fast chirp内获得了N s个采样点，做N range点距离维度快速傅里叶变换；slow chirp上获得了N slow个采样点，做N doppler点速度维度快速傅里叶变换，共获得了U*N Rx个虚拟接收阵子分别对应的RD图。
处理单元将U*N Rx个虚拟接收阵子的两维傅里叶变换结果累加获得总RD图。示例性地，U*N Rx个虚拟接收阵子的两维傅里叶变换结果累加是指将U*N Rx个虚拟接收阵子分别对应的RD图累加，获得一个总RD图。其中，U*N Rx个虚拟接收阵子的两维傅里叶变换结果累加可以采用非相干叠加，即U*N Rx个虚拟接收阵子的二维傅里叶的幅值叠加，或者采用非相干叠加，即U*N Rx个虚拟接收阵子的二维傅里叶的在固定波束上合成的峰值的复数叠加，或者其他的叠加方式，本申请不做特别限制。
其中，RD图：一个维度为距离信息，一个维度为多普勒信息的雷达输出图形。从距离维度抽取称为Range bin，从多普勒维度抽取称为多普勒单元(Doppler bin)，同时从距离和多普勒维度抽取成为距离-多普勒单元(Range-Doppler Cell)。
具体的，处理单元在总RD图上检测目标。示例性地，处理单元可以采用现有的各种检测方法进行检测，例如有序统计-恒虚警率(检测)(Ordered Statistic-Constant False Alarm Rate，OS-CFAR)或单元平均-恒虚警率(检测)(Cell-Averaging Constant False Alarm Rate， CA-CFAR)等常用检测方法，本申请对此不作限定。
处理单元在总RD图上检测到一个目标后，处理单元提取该目标对应的重叠阵子在总RD图上的信号。每个目标对应的重叠阵子在总RD图上的信号包括发射间隔为N 1的重叠阵子在总RD图上的信号和发射间隔为N 2的重叠阵子在总RD图上的信号。
示例性地，处理单元可以采用但不限于以下方式确定第一混叠系数，处理单元可以采用相同的方式确定第二混叠系数，重复之处不再赘述。
其中，任意一个重叠阵子可以采用(m，n)和(m，n’)表示，d mn＝d m′n′，其中，发射天线m在U个时隙中的时隙u发射chirp信号，发射天线m和接收天线n形成的虚拟接收天线阵子的位置为d mn，发射天线m’在U个时隙中的时隙u’发射chirp信号，发射天线m’和接收天线n’形成的虚拟接收天线阵子的位置d m’n’，|u-u’|＝N ii，重叠阵子对应的发射间隔为N ii。
在U个时隙中的时隙u内发射天线m发射chirp信号，如果该信号的波形表示为S(t)，经过距离R i，径向速度为V i，水平角度为θ i(以水平角为例)的目标反射后，发射天线m和接收天线n形成的虚拟接收阵子可以表示从总RD图中获得目标检测距离和混叠后速度的标识(R ind,V ind)，其中测量到的目标距离可以表示为
Figure PCTCN2020080977-appb-000001
其中R Res是距离分辨率。在虚拟接收阵子对应的RD图上，取(R ind,V ind)对应的RD单元中的复数值
Figure PCTCN2020080977-appb-000002
该复数值的相位
Figure PCTCN2020080977-appb-000003
可以表示为：
Figure PCTCN2020080977-appb-000004
因此，对于任意一个重叠阵子(m，n)和(m’,n’)，d mn＝d m′n′，当目标的速度为零的时候，则
Figure PCTCN2020080977-appb-000005
当重叠阵子对应的发射间隔为N ii，即|u-u’|＝N ii，目标的速度不为零时，则相位差
Figure PCTCN2020080977-appb-000006
和目标径向速度的关系由公式2变换得到，为
Figure PCTCN2020080977-appb-000007
不失一般性取u>u’。
可以理解地，
Figure PCTCN2020080977-appb-000008
其中，V i_amb是通过总RD map获得的混叠后的速度，即
Figure PCTCN2020080977-appb-000009
是速度分辨率。进一步地，可以根据
Figure PCTCN2020080977-appb-000010
Figure PCTCN2020080977-appb-000011
遍历k Nii的取值范围内的各个取值使得该表达式最接近于0的
Figure PCTCN2020080977-appb-000012
为混叠系数。
Figure PCTCN2020080977-appb-000013
为虚拟接收阵子对应的RD图上对应d mn的信号，
Figure PCTCN2020080977-appb-000014
为虚拟接收阵子对应的RD图上对应d m′n′的信号，
Figure PCTCN2020080977-appb-000015
的取值范围由发射间隔N ii确定。
进一步地，根据所有发射间隔为N ii的重叠阵子分别求得的
Figure PCTCN2020080977-appb-000016
求平均值，作为目标对应的发射间隔为N ii的重叠阵子对应的混叠系数。
应理解的是，确定第一混叠系数和第二混叠系数还可以采用其他方案，本申请对此不作限定。
步骤440：处理单元根据第一混叠系数和第二混叠系数确定第一目标的速度。
在一种可能的设计中，处理单元可以采用但不限于以下方法确定第一目标的速度：
首先，处理单元根据N 1确定第一混叠系数范围，以及根据N 2确定第二混叠系数范围。
不同发射间隔的重叠阵子对应的测速范围不同，即时间上相邻发送(及发射间隔为1),|u-u’|＝N ii＝1的重叠阵子测速范围为±V max＝λ/(4*T C)，发射间隔为N ii的重叠阵子对应的测速范围为±V max＝λ/(4*N ii*T C)。发射周期为U的MIMO雷达对应的测速范围为±V max＝λ/(4*U*T C)，U≥N Tx。
可以理解的，发射间隔为1的重叠阵子可以相对发射周期为U的MIMO雷达获得目标的速度的U倍扩展，混叠系数的取值有U个。发射间隔为N ii的重叠阵子可以相对发射周期为U的MIMO雷达获得目标的速度的U/N ii倍扩展,发射间隔为N ii的重叠阵子对应的混叠系数的取值U/N ii个。混叠系数可以用1,2，…,U/N ii具体指示混叠的倍数0,1，…,U/N ii-1，其中0表示没有混叠。车载环境的速度的正负关系，可以在多组N ii后折算，也在这里折算。本申请举例仅以多组N ii后折算为例进行说明。
那么可以理解为，发射间隔为N 1的重叠阵子对应的可以用1,2，…,U/N 1混叠系数混淆范围为0,1,…,U/(N 1-1)的混叠，发射间隔为N 2的重叠阵子对应的混淆系数范围为0,1,…,U/(N 2-1)。
然后，处理单元根据第一混叠系数范围、第一混叠系数和N 1确定第一混叠系数集合，以及根据第二混叠系数范围、第二混叠系数和N 2确定第二混叠系数集合。
其中，第一混叠系数集合包括将第一混叠系数折算至第三混叠系数范围的可能混叠系数，第二混叠系数集合包括将第二混叠系数折算至第三混叠系数范围的可能混叠系数，第三混叠系数范围为发射间隔为1的重叠阵子对应的混叠系数范围。
由上可知，
Figure PCTCN2020080977-appb-000017
由于不同发射间隔的重叠阵子对应
Figure PCTCN2020080977-appb-000018
取值范围不同，不同发射间隔的重叠阵子对应V i_amb相同，因此，不同发射间隔的重叠阵子对应的混叠系数
Figure PCTCN2020080977-appb-000019
存在一定折算关系，为了减轻重叠阵子受到的噪声影响，不能直接把不同发射间隔的重叠阵子对应的混叠系数直接相加求平均，或者求加权平均。
示例性地，当N ii>1时，发射间隔为N ii的重叠阵子对应的混叠系数折算至发射间隔为1的重叠阵子对应的混叠系数范围的方法如下：
Figure PCTCN2020080977-appb-000020
其中，N ii表示发射间隔，
Figure PCTCN2020080977-appb-000021
为发射间隔为N ii的重叠阵子对应的混叠系数。k为发射间隔为N ii的重叠阵子对应的混叠系数折算后的混叠系数,当N ii>1时，j有多个取值，因此，也把k的多个取值称为混叠系数集合，即与发射间隔为N ii的重叠阵子对应的混叠系数折算至发射间隔为1的重叠阵子对应的混叠系数的集合。
接下来，处理单元根据第一混叠系数集合和第二混叠系数集合确定第三混叠系数和第四混叠系数，第三混叠系数为第一混叠系数集合中的一个混叠系数，第四混叠系数为第二混叠系数集合中的一个混叠系数。
其中，第三混叠系数和第四混叠系数的差值为第一混叠系数集合中的任意一个混叠系数与第二混叠系数集合中的任意一个混叠系数的差值中的最小值。
进一步地，处理单元对第三混叠系数和第四混叠系数进行处理：
在一示例中，处理单元计算第三混叠系数和第四混叠系数的平均值。
在另一示例中，处理单元计算第三混叠系数和第四混叠系数的加权平均值。例如，可以根据不同发射间隔的重叠阵子的数目，或者通道上的信号噪声比等方式确定第三混叠系数和第四混叠系数分别对应的权值。
示例1：如图7所示，当N 1＝1,N 2＝2,N 3＝3,U＝24时，发射间隔为1的重叠阵子对应的混叠系数范围为1,2,3,…24，发射间隔为2的重叠阵子对应的混叠系数范围为1,2,3,…12，发射间隔为3的重叠阵子对应的混叠系数范围范为1,2,3,…8。以下以目标1为例，说明书确定目标1对应的不同发射间隔的重叠阵子对应的混叠系数的折算过程。
k 1＝13，N 1＝1，则k＝k 1，该混叠系数为发射间隔为1的重叠阵子对应的混叠系数，因此不需要折算。
k 2＝5，N 2＝2，为偶数，由于k 2小于6，则k＝11或23。
具体的，可以包括没有混叠或混叠一倍两种情况，如果没有混叠，k＝5+12/2＝11，如果混叠一倍，k＝5+3*12/2＝23。
k 3＝4，N 3＝3，为奇数，则k＝4,12或20。
具体的，可以包括没有混叠、混叠一倍、混叠两倍三种情况，如果没有混叠，k＝4+0*24/3＝4，如果混叠一倍，k＝4+1*24/3＝12，如果混叠两倍，k＝4+2*24/3＝20。
进一步地，在将上述三个不同发射间隔的重叠阵子对应的混叠系数进行折算后，当k＝13，k＝11,k＝12时三者差值最小，此时，将上述三个值取平均值，(13+12+11)/3)＝12。
可以理解的，如果天线阵列和发射顺序中没有相邻间隔发射形成的重叠阵子，可以通过类似的方法进行折算。
示例2：当N 1＝2,N 2＝3,U＝24时，发射间隔为2的重叠阵子对应的混叠系数范围为1,2,3,…12，发射间隔为3的重叠阵子对应的混叠系数范围范为1,2,3,…8。以下以目标1为例，说明书确定目标1对应的不同发射间隔的重叠阵子对应的混叠系数的折算过程。
k 2＝5，N 1＝2，为偶数，由于k 2小于6，则k＝11或23。
具体的，可以包括没有混叠或混叠一倍两种情况，如果没有混叠，k＝5+12/2＝11，如果混叠一倍，k＝5+3*12/2＝23。
k 3＝4，N 2＝3，为奇数，则k＝4,12或20。
具体的，可以包括没有混叠、混叠一倍、混叠两倍三种情况，如果没有混叠，k＝4+0*24/3＝4，如果混叠一倍，k＝4+1*24/3＝12，如果混叠两倍，k＝4+2*24/3＝20。
进一步地，在将上述2个不同发射间隔的重叠阵子对应的混叠系数进行折算后，当k＝11,k＝12时2者差值最小，此时，将上述2个值取平均值四舍五入，round(12+11)/2)＝12。
因此，通过将多种发射间隔的重叠阵子分别对应的混叠系数进行折算，并对折算后的混叠系数进行处理，得到在发射间隔为1的重叠阵子对应的混叠系数范围内的混叠系数，并实现将混叠后的第一目标的速度恢复至Tc确定的最大测速范围。
此外，应理解的是，由于速度可以被定义为正负，因此，当U为奇数，混叠系数范围为[-U/2,U/2]，当U为偶数，混叠系数范围为[-U/2,U/2)。
进一步求解以下参数：
Figure PCTCN2020080977-appb-000022
k∈1，2，U为奇数
Figure PCTCN2020080977-appb-000023
k∈1，2，U，U为偶数，
Figure PCTCN2020080977-appb-000024
Figure PCTCN2020080977-appb-000025
k∈1，2，U，U为偶数，
Figure PCTCN2020080977-appb-000026
其中dopplerInd amb表示总RD图上检测到的第一目标的混叠后的多普勒标识V ind，N doppler表示RD图的多普勒维度。这样可以把混叠后的速度扩展到整个U*N doppler范围的数值，i表示第一目标通过多组发射间隔的重叠阵子获得的混叠系数，例如，i为根据示例1中三个不同发射间隔分别对应的k求得的平均值。处理单元根据获得的dopplerInd umamb和速度分辨率获得第一目标的速度。可以理解的，N doppler大于等于N slow，大于N slow的chirp中的值，通常采用补零处理。
如图8所示，本申请实施例还提供一种雷达设备800，该雷达设备为MIMO雷达，MIMO雷达包括发射器801、接收器802和处理单元803，发射器包括N Tx个发射天线，接收器包括N Rx个接收天线，其中，N Tx和N Rx均为大于等于2的正整数，雷达设备800用于执行上述如图4所示的方法。
综上所述，采用本申请实施例提供的方法，通过N Tx个发射天线的预设发射顺序可以实现构造多种发射间隔的重叠阵子以及提高重叠阵子的数目，在针对每个目标的速度进行求解时，可以根据多种发射间隔的重叠阵子以及较多的重叠阵子的数目，计算多种发射间隔的重叠阵子分别对应的混叠系数，即使上述重叠阵子中的部分重叠阵子的相位差受噪声影响较大，导致相应的混叠系数的求解不准确，但是根据多种发射间隔的重叠阵子分别对应的混叠系数求解目标的速度，能够有效减轻受噪声影响较大的重叠阵子对应的混叠系数对速度求解带来的影响，提升目标速度求解的准确性。此外，采用上述方法，不会造成虚拟天线口径的损失。
本领域内的技术人员应明白，本申请实施例可提供为方法、系统、或计算机程序产品。因此，本申请实施例可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施例的形式。而且，本申请实施例可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。
本申请实施例是参照根据本申请实施例的方法、设备(系统)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图中的流程和/或方框的结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方 式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。
显然，本领域的技术人员可以对本申请实施例进行各种改动和变型而不脱离本申请的精神和范围。这样，倘若本申请实施例的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也意图包含这些改动和变型在内。

Claims (20)

  1. 一种雷达信号发射方法，其特征在于，应用于多输入多输出MIMO雷达，所述MIMO雷达包括发射器和接收器，所述发射器包括N Tx个发射天线，所述接收器包括N Rx个接收天线，其中，N Tx和N Rx均为大于等于2的正整数，所述方法包括：
    确定测量帧的配置信息，其中，所述测量帧的配置信息指示所述N Tx个发射天线的预设发射顺序、每个啁啾chirp信号的发射持续时间T c和所述N Tx个发射天线按照所述预设发射顺序重复发射的次数N slow；
    根据所述测量帧的配置信息发送所述测量帧，所述测量帧包括U*N slow个chirp信号，其中，所述U*N slow个chirp信号包括N slow组chirp信号，每组chirp信号包括U个chirp信号，所述U个chirp信号是所述N Tx个发射天线按照所述预设发射顺序在U个时隙分别发射的，每个chirp信号的发射持续时间T c记作一个时隙；所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 1的重叠阵子和发射间隔为N 2的重叠阵子，N 1≠N 2，N 1为正整数，N 2为正整数，U≥N Tx。
  2. 如权利要求1所述的方法，其特征在于，针对每组chirp信号，发射天线m1在所述U个时隙中的时隙u 1发射chirp信号，发射天线m1和接收天线n1形成的虚拟接收天线阵子的位置为d m1n1，发射天线m1’在所述U个时隙中的时隙u 1’发射chirp信号，发射天线m1’和接收天线n1’形成的虚拟接收天线阵子的位置为d m1’n1’，发射天线m2在所述U个时隙中的时隙u 2发射chirp信号，发射天线m2和接收天线n2形成的虚拟接收天线阵子的位置为d m2n2，发射天线m2’在所述U个时隙中的时隙u 2’发射chirp信号，发射天线m2’和接收天线n2’形成的虚拟接收天线阵子的位置为d m2’n2’，所述发射间隔为N 1的重叠阵子满足d m1n1＝d m1’n1’，所述发射间隔为N 2的重叠阵子满足d m2n2＝d m2’n2’；
    其中，|u 1-u 1’|＝N 1，|u 2-u 2’|＝N 2；m1、n1、m1’、n1’、m2、n2、m2’、n2’均为大于等于0的整数，u 1、u 1’、u 2、u 2’均为大于等于0的整数。
  3. 如权利要求1或2所述的方法，其特征在于，所述N Tx个发射天线中存在至少一个发射天线在所述U个时隙中发射了2次chirp信号。
  4. 如权利要求1-3任一项所述的方法，其特征在于，所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 3的重叠阵子，N 2≠N 2≠N 3，N 3为正整数。
  5. 一种雷达信号接收方法，其特征在于，应用于MIMO雷达，所述MIMO雷达包括发射器和接收器，所述发射器包括N Tx个发射天线，所述接收器包括N Rx个接收天线，其中，N Tx和N Rx均为大于等于2的正整数，所述方法包括：
    接收测量帧经至少一个目标反射后形成的回波信号，所述测量帧包括U*N slow个chirp信号，其中，所述U*N slow个chirp信号包括N slow组chirp信号，每组chirp信号包括U个chirp信号，所述U个chirp信号是所述N Tx个发射天线按照预设发射顺序在U个时隙分别发射的，每个chirp信号的发射持续时间T c记作一个时隙；所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 1的重叠阵子和发射间隔为N 2的重叠阵子，N 1≠N 2，N 1为正整数，N 2为正整数，U≥N Tx；
    根据所述回波信号确定第一混叠系数和第二混叠系数；其中，所述第一混叠系数为第一目标对应的发射间隔为N 1的重叠阵子对应的混叠系数，所述第二混叠系数为所述第一目 标对应的发射间隔为N 2的重叠阵子对应的混叠系数，所述第一目标为所述至少一个目标中的任意一个目标；
    根据第一混叠系数和第二混叠系数确定所述第一目标的速度。
  6. 如权利要求5所述的方法，其特征在于，针对每组chirp信号，发射天线m1在所述U个时隙中的时隙u 1发射chirp信号，发射天线m1和接收天线n1形成的虚拟接收天线阵子的位置为d m1n1，发射天线m1’在所述U个时隙中的时隙u 1’发射chirp信号，发射天线m1’和接收天线n1’形成的虚拟接收天线阵子的位置为d m1’n1’，发射天线m2在所述U个时隙中的时隙u 2发射chirp信号，发射天线m2和接收天线n2形成的虚拟接收天线阵子的位置为d m2n2，发射天线m2’在所述U个时隙中的时隙u 2’发射chirp信号，发射天线m2’和接收天线n2’形成的虚拟接收天线阵子的位置为d m2’n2’，所述发射间隔为N 1的重叠阵子满足d m1n1＝d m1’n1’，所述发射间隔为N 2的重叠阵子满足d m2n2＝d m2’n2’；
    其中，|u 1-u 1’|＝N 1，|u 2-u 2’|＝N 2；m1、n1、m1’、n1’、m2、n2、m2’、n2’均为大于等于0的整数，u 1、u 1’、u 2、u 2’均为大于等于0的整数。
  7. 如权利要求5或6所述的方法，其特征在于，根据第一混叠系数和第二混叠系数确定所述第一目标的速度，包括：
    根据N 1确定第一混叠系数范围，以及根据N 2确定第二混叠系数范围；
    根据所述第一混叠系数范围、所述第一混叠系数和N 1确定第一混叠系数集合，以及根据所述第二混叠系数范围、所述第二混叠系数和N 2确定第二混叠系数集合；其中，所述第一混叠系数集合包括将所述第一混叠系数折算至第三混叠系数范围的可能混叠系数，所述第二混叠系数集合包括将所述第二混叠系数折算至所述第三混叠系数范围的可能混叠系数，所述第三混叠系数范围为发射间隔为1的重叠阵子对应的混叠系数范围；
    根据所述第一混叠系数集合和所述第二混叠系数集合确定第三混叠系数和第四混叠系数，所述第三混叠系数为所述第一混叠系数集合中的一个混叠系数，所述第四混叠系数为所述第二混叠系数集合中的一个混叠系数；
    根据所述第三混叠系数和所述第四混叠系数确定所述第一目标的速度。
  8. 如权利要求7所述的方法，其特征在于，所述第三混叠系数和所述第四混叠系数的差值为所述第一混叠系数集合中的任意一个混叠系数与所述第二混叠系数集合中的任意一个混叠系数的差值中的最小值。
  9. 如权利要求7或8所述的方法，其特征在于，根据所述第三混叠系数和所述第四混叠系数确定所述第一目标的速度，包括：
    根据所述第三混叠系数和所述第四混叠系数的平均值确定所述第一目标的速度；
    或者，根据所述第三混叠系数和所述第四混叠系数的加权平均值确定所述第一目标的速度。
  10. 如权利要求5-9任一项所述的方法，其特征在于，所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 3的重叠阵子，N 2≠N 2≠N 3，N 3为正整数。
  11. 一种雷达设备，其特征在于，所述设备为MIMO雷达，所述MIMO雷达包括发射器、接收器和处理单元，所述发射器包括N Tx个发射天线，所述接收器包括N Rx个接收天线，其中，N Tx和N Rx均为大于等于2的正整数，其中：
    所述处理单元，用于确定测量帧的配置信息，其中，所述测量帧的配置信息指示所述 N Tx个发射天线的预设发射顺序、每个啁啾chirp信号的发射持续时间T c和所述N Tx个发射天线按照所述预设发射顺序重复发射的次数N slow；
    所述发射器，用于根据所述测量帧的配置信息发送所述测量帧，所述测量帧包括U*N slow个chirp信号，其中，所述U*N slow个chirp信号包括N slow组chirp信号，每组chirp信号包括U个chirp信号，所述U个chirp信号是所述N Tx个发射天线按照所述预设发射顺序在U个时隙分别发射的，每个chirp信号的发射持续时间T c记作一个时隙；所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 1的重叠阵子和发射间隔为N 2的重叠阵子，N 1≠N 2，N 1为正整数，N 2为正整数，U≥N Tx。
  12. 如权利要求11所述的设备，其特征在于，针对每组chirp信号，发射天线m1在所述U个时隙中的时隙u 1发射chirp信号，发射天线m1和接收天线n1形成的虚拟接收天线阵子的位置为d m1n1，发射天线m1’在所述U个时隙中的时隙u 1’发射chirp信号，发射天线m1’和接收天线n1’形成的虚拟接收天线阵子的位置为d m1’n1’，发射天线m2在所述U个时隙中的时隙u 2发射chirp信号，发射天线m2和接收天线n2形成的虚拟接收天线阵子的位置为d m2n2，发射天线m2’在所述U个时隙中的时隙u 2’发射chirp信号，发射天线m2’和接收天线n2’形成的虚拟接收天线阵子的位置为d m2’n2’，所述发射间隔为N 1的重叠阵子满足d m1n1＝d m1’n1’，所述发射间隔为N 2的重叠阵子满足d m2n2＝d m2’n2’；
    其中，|u 1-u 1’|＝N 1，|u 2-u 2’|＝N 2；m1、n1、m1’、n1’、m2、n2、m2’、n2’均为大于等于0的整数，u 1、u 1’、u 2、u 2’均为大于等于0的整数。
  13. 如权利要求11或12所述的设备，其特征在于，所述N Tx个发射天线中存在至少一个发射天线在所述U个时隙中发射了2次chirp信号。
  14. 如权利要求11-13任一项所述的设备，其特征在于，所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 3的重叠阵子，N 2≠N 2≠N 3，N 3为正整数。
  15. 一种雷达设备，其特征在于，所述设备为MIMO雷达，所述MIMO雷达包括发射器、接收器和处理单元，所述发射器包括N Tx个发射天线，所述接收器包括N Rx个接收天线，其中，N Tx和N Rx均为大于等于2的正整数，其中：
    所述接收器，用于接收测量帧经至少一个目标反射后形成的回波信号，所述测量帧包括U*N slow个chirp信号，其中，所述U*N slow个chirp信号包括N slow组chirp信号，每组chirp信号包括U个chirp信号，所述U个chirp信号是所述N Tx个发射天线按照预设发射顺序在U个时隙分别发射的，每个chirp信号的发射持续时间T c记作一个时隙；所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 1的重叠阵子和发射间隔为N 2的重叠阵子，N 1≠N 2，N 1为正整数，N 2为正整数，U≥N Tx；
    所述处理单元，用于根据所述回波信号确定第一混叠系数和第二混叠系数；其中，所述第一混叠系数为第一目标对应的发射间隔为N 1的重叠阵子对应的混叠系数，所述第二混叠系数为所述第一目标对应的发射间隔为N 2的重叠阵子对应的混叠系数，所述第一目标为所述至少一个目标中的任意一个目标；根据第一混叠系数和第二混叠系数确定所述第一目标的速度。
  16. 如权利要求15所述的设备，其特征在于，针对每组chirp信号，发射天线m1在所述U个时隙中的时隙u 1发射chirp信号，发射天线m1和接收天线n1形成的虚拟接收天线阵子的位置为d m1n1，发射天线m1’在所述U个时隙中的时隙u 1’发射chirp信号，发射天 线m1’和接收天线n1’形成的虚拟接收天线阵子的位置为d m1’n1’，发射天线m2在所述U个时隙中的时隙u 2发射chirp信号，发射天线m2和接收天线n2形成的虚拟接收天线阵子的位置为d m2n2，发射天线m2’在所述U个时隙中的时隙u 2’发射chirp信号，发射天线m2’和接收天线n2’形成的虚拟接收天线阵子的位置为d m2’n2’，所述发射间隔为N 1的重叠阵子满足d m1n1＝d m1’n1’，所述发射间隔为N 2的重叠阵子满足d m2n2＝d m2’n2’；
    其中，|u 1-u 1’|＝N 1，|u 2-u 2’|＝N 2；m1、n1、m1’、n1’、m2、n2、m2’、n2’均为大于等于0的整数，u 1、u 1’、u 2、u 2’均为大于等于0的整数。
  17. 如权利要求15或16所述的设备，其特征在于，所述处理单元，用于：
    根据N 1确定第一混叠系数范围，以及根据N 2确定第二混叠系数范围；
    根据所述第一混叠系数范围、所述第一混叠系数和N 1确定第一混叠系数集合，以及根据所述第二混叠系数范围、所述第二混叠系数和N 2确定第二混叠系数集合；其中，所述第一混叠系数集合包括将所述第一混叠系数折算至第三混叠系数范围的可能混叠系数，所述第二混叠系数集合包括将所述第二混叠系数折算至所述第三混叠系数范围的可能混叠系数，所述第三混叠系数范围为发射间隔为1的重叠阵子对应的混叠系数范围；
    根据所述第一混叠系数集合和所述第二混叠系数集合确定第三混叠系数和第四混叠系数，所述第三混叠系数为所述第一混叠系数集合中的一个混叠系数，所述第四混叠系数为所述第二混叠系数集合中的一个混叠系数；
    根据所述第三混叠系数和所述第四混叠系数确定所述第一目标的速度。
  18. 如权利要求17所述的设备，其特征在于，所述第三混叠系数和所述第四混叠系数的差值为所述第一混叠系数集合中的任意一个混叠系数与所述第二混叠系数集合中的任意一个混叠系数的差值中的最小值。
  19. 如权利要求17或18所述的设备，其特征在于，所述处理单元，用于：
    根据所述第三混叠系数和所述第四混叠系数的平均值确定所述第一目标的速度；
    或者，根据所述第三混叠系数和所述第四混叠系数的加权平均值确定所述第一目标的速度。
  20. 如权利要求15-19任一项所述的设备，其特征在于，所述N Tx个发射天线与所述N Rx个接收天线形成的虚拟接收阵列包括发射间隔为N 3的重叠阵子，N 2≠N 2≠N 3，N 3为正整数。
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