WO2021243491A1 - 一种雷达信号发射和接收方法及装置 - Google Patents

一种雷达信号发射和接收方法及装置 Download PDF

Info

Publication number
WO2021243491A1
WO2021243491A1 PCT/CN2020/093630 CN2020093630W WO2021243491A1 WO 2021243491 A1 WO2021243491 A1 WO 2021243491A1 CN 2020093630 W CN2020093630 W CN 2020093630W WO 2021243491 A1 WO2021243491 A1 WO 2021243491A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
time slots
transmitting antennas
transmitting
sub
Prior art date
Application number
PCT/CN2020/093630
Other languages
English (en)
French (fr)
Inventor
劳大鹏
刘劲楠
刘荣江
杨晨
朱金台
李德建
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
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 PCT/CN2020/093630 priority Critical patent/WO2021243491A1/zh
Priority to CN202210129330.5A priority patent/CN114660544A/zh
Priority to CN202080004671.9A priority patent/CN112639507B/zh
Priority to EP20939284.4A priority patent/EP4148451A4/en
Priority to CA3180930A priority patent/CA3180930A1/en
Priority to JP2022573474A priority patent/JP2023527226A/ja
Publication of WO2021243491A1 publication Critical patent/WO2021243491A1/zh
Priority to US18/071,333 priority patent/US20230092131A1/en

Links

Images

Classifications

    • 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
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/35—Details of non-pulse systems
    • 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
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • 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
    • G01S13/325—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of coded signals, e.g. P.S.K. signals
    • 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
    • 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
    • G01S13/50—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
    • 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
    • G01S2013/0236—Special technical features
    • G01S2013/0245—Radar with phased array antenna
    • G01S2013/0263—Passive array antenna

Definitions

  • This application relates to the field of radar technology, and in particular to a method and device for transmitting and receiving radar signals.
  • 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 angle 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 chirp scan period is several ms level, and it is reduced to ⁇ s level, which decouples the measurement distance and measurement speed and reduces the probability of false targets;
  • the number of channels is changed from single input multiple output, SIMO ) Model has evolved to a multiple input multiple output (MIMO) model, and the antenna scale continues to expand, so that the virtual antenna aperture is enlarged, thereby improving the angular resolution, which can meet the goal of achieving a higher space for autonomous driving.
  • Resolution requirements Since it is necessary to separate the signals of multiple transmitting antennas to obtain the target angle, it is necessary to design the orthogonal waveforms of the multiple transmitting antennas.
  • Multiple transmitting antennas of MIMO radar can use time division multiplexing (TDM) to transmit chirp signals, so as to expand the virtual antenna aperture, that is, TDM MIMO waveform.
  • TDM time division multiplexing
  • CDM Code Division Multiple Access
  • CDM also has documents called Doppler Division Multiplex (DDM) or Doppler Division Multiple Access (DDM).
  • Doppler-Division Multiple Access, DDMA Doppler-Division Multiple Access
  • the purpose of this application is to provide a method and device for transmitting and receiving radar signals, which overcomes the problem that the orthogonal waveforms sent by the existing radar devices cannot meet the requirements for speed measurement range and angular resolution at the same time.
  • the present application provides a radar signal transmitting method, which is applied to a radar device.
  • the radar device includes N transmitting antennas, where N is an integer greater than 2, and m is an integer greater than or equal to 2 and less than N.
  • the first signal since the first signal only includes the signal of one transmitting antenna and occupies S consecutive time slots, the first signal may be a SIMO signal, which has the advantage of a larger speed measurement range.
  • the second signal includes signals sent by m transmitting antennas, which can be understood as a MIMO signal, and its advantage is that the measured angular resolution is relatively large.
  • the number of time slots between adjacent time slots, M is an integer greater than or equal to m/(P-1).
  • the velocity resolution of the measured target velocity is ⁇ /(2*S*Tchip), which is inversely proportional to the size of S, the larger S is, the smaller the velocity resolution is, and the more accurate the velocity of the target is obtained.
  • ⁇ is the wavelength of the modulation frequency
  • Tchip is the duration of a time slot.
  • m transmit antennas occupy the same time slot using 2 ⁇ k y / P step of phase modulation, different k y values.
  • one transmitting antenna uses a step size of 2 ⁇ /P for phase modulation
  • the other transmitting antenna uses a step size of 4 ⁇ /P for phase modulation.
  • the transmitting antennas occupying the same time slot adopt different step lengths for phase modulation, which can distinguish the signals sent by different transmitting antennas by phase and improve the accuracy of target detection.
  • P phases are generated by phase shifters including [0, 2 ⁇ /P, 4 ⁇ /P, 6 ⁇ /P,..., (P-1)*2 ⁇ /P] phases.
  • the third signal in S0 time slots after S time slots, can also be transmitted in a time division manner through m transmitting antennas, and S0 is an integer greater than 1.
  • the velocity of the target can be combined with the velocity resolution of the first signal, and the Doppler phase corresponding to the velocity of the target can be obtained.
  • transmitting the second signal in at least one of time division mode or code division mode through m transmission antennas out of N transmission antennas in S time slots includes: in S time slots For the first S1 time slots in the m transmitting antennas, N1 transmitting antennas are cycled with P*M1 time slots, and P*M1 time slots that do not conflict are selected from the P*M1 time slots in a cycle.
  • the second signal is sent through the slots respectively; in the last S2 time slots of the S time slots, through the N2 transmitting antennas except for the N1 transmitting antennas among the m transmitting antennas, the period is P*M2 time slots.
  • the maximum velocity measurement range is different.
  • two targets whose echo velocity is aliased at the interval of M1, in the echo interval of M2 it can be easily distinguish.
  • the reverse is also true.
  • the two targets that are aliased in velocity in the echo with a spacing of M2 can be easily distinguished in the echo with a spacing of M1. Therefore, by setting different time slot intervals M1 and M2, it is easier to determine the actual target number and avoid missing reflected targets with weak echoes.
  • the signal waveform of the first signal in S time slots may be FMCW; the signal waveform of the second signal in S time slots may also be FMCW.
  • other waveforms used by MIMO radars may also be used, for example, pulse waveforms or Orthogonal Frequency Division Multiplex (OFDM) waveforms may also be used.
  • OFDM Orthogonal Frequency Division Multiplex
  • P 2, 3, or 4.
  • the first signal and the second signal are respectively modulated and coded with different phases, and only 4 phases or less are used, which reduces the accuracy requirements of the phase modulator and reduces the requirements for the chip.
  • the intersection between the m transmitting antennas that transmit the second signal and the one transmitting antenna that transmits the first signal is 0, that is, the m transmit antennas that transmit the second signal are the same as the m transmit antennas that transmit the first signal.
  • One transmitting antenna is a different transmitting antenna among N transmitting antennas.
  • the present application provides a radar signal receiving method applied to a radar device.
  • the radar device includes N transmitting antennas and at least one receiving antenna, where m is an integer greater than or equal to 2, and less than N, and N greater than 2.
  • the method includes: obtaining M sub-distance-Doppler RD patterns of each receiving antenna in at least one receiving antenna; detecting the first target according to the sub-RD pattern accumulated by the M sub-RD patterns of each receiving antenna, and obtaining Distance information of the first target; the first target is one or more targets among at least one target.
  • the i-th sub-RD pattern in the M sub-RD patterns of each receiving antenna is that the receiving antenna’s initial slot is i in the echo signal of the S slots, and the signal of every M slots is two-dimensionally fast
  • the result of the Fourier transform 2D-FFT, i takes any integer of 1, 2, ..., M; the echo signal is formed after the first signal and the second signal are reflected by at least one target; where the first signal is in S The phase of the first signal is unchanged in S time slots; the second signal is transmitted through m of N transmitting antennas in S time slots.
  • the antenna is transmitted by at least one of time division and code division; the signal transmitted through each of the m transmitting antennas in the second signal is phase modulated with a step length of 2 ⁇ k y /P, and P is greater than 1.
  • the total RD pattern is used to detect the Doppler spectral lines of the aliasing velocity of a target, and there are (P-1)*M+1 Doppler spectral lines that need to be matched.
  • the accumulated sub-RD pattern is used to detect a target. Since there are only P Doppler spectral lines corresponding to the same target, which is much smaller than the number of Doppler spectral lines corresponding to the detection using the total RD pattern, so , It is easier to detect the Doppler spectrum line of the aliasing velocity of a target using the sub-RD image than the total RD image.
  • the RD graph one dimension is distance information, and the other dimension is the radar output graph of Doppler information. Extracting from the distance dimension is called the distance unit (Range bin), and extracting from the Doppler dimension is called the Doppler unit (Doppler bin). At the same time, extracting from the distance and Doppler dimensions is called the range-Doppler unit (Range-Doppler). Cell).
  • a total RD pattern can also be obtained, and the total RD pattern may be the result of performing a two-dimensional FFT (2D-FFT) on all adjacent time slots in S time slots.
  • 2D-FFT two-dimensional FFT
  • the method further includes: determining at least one Doppler index Vind_sub of the aliasing speed of the first signal on the accumulated sub-RD map of the first target, and the accumulated sub-RD of the first target At least one Doppler index Vind_sub of the aliasing velocity of the first signal on the graph is located in P possible positions of the interval Nfft/P, where Nfft is the dimension of the 2D-FFT of the accumulated sub-RD image.
  • the method further includes: matching the accumulated sub-RD map and the total RD map, determining at least one Doppler index Vind_total of the non-aliasing velocity of the first target, and the first target At least one Doppler index Vind_sub of the corresponding aliasing velocity on the accumulated sub-RD map.
  • the method further includes: compensating the Doppler phase deviation caused by the time division of the m transmitting antennas and the phase deviation caused by the code division, and obtaining the angle information of the first target. By compensating the phase deviation, more accurate angle information can be obtained.
  • a radar device in a third aspect, includes an antenna array, a processor, and a microwave integrated circuit.
  • the antenna array includes N transmitting antennas, where N is an integer greater than 2, where:
  • the processor is used to determine the first signal and the second signal in any possible design as in the first aspect
  • Microwave integrated circuit used to generate the first signal and the second signal determined by the processor
  • the antenna array is used to transmit the first signal and the second signal generated by the microwave integrated circuit.
  • a radar device in a fourth aspect, includes a receiver and a processor, and the receiver includes at least one receiving antenna, wherein:
  • the processor is configured to execute any of the possible design methods in the two aspects according to the echo signal.
  • a radar device including: a memory and a processor, the memory is used to store instructions, the processor is used to execute the instructions stored in the memory, and the execution of the instructions stored in the memory enables the processor to generate In any possible design, the first signal and the second signal.
  • a radar device including a memory and a processor, the memory is used to store instructions, the processor is used to execute the instructions stored in the memory, and the execution of the instructions stored in the memory is such that the processor is used to execute the second aspect Any possible design method.
  • a readable storage medium including a computer program or instruction.
  • the computer program or instruction When the computer program or instruction is executed, the method in any possible design of the first aspect or the second aspect is executed.
  • a computer program product which includes computer-readable instructions.
  • the radar device reads and executes the computer-readable instructions, the radar device executes any possible design method as in the first aspect or the second aspect .
  • 1(a) to 1(b) are schematic diagrams of the structure of a radar device suitable for an embodiment of the present application;
  • FIG. 2 is a schematic structural diagram of a vehicle provided by an embodiment of the application.
  • FIG. 3 is a schematic diagram of a radar signal transmission process provided by an embodiment of the application.
  • FIG. 4 is a schematic diagram of a radar signal provided by an embodiment of this application.
  • FIG. 5 is a schematic diagram of another radar signal provided by an embodiment of this application.
  • FIG. 6 is a schematic diagram of another radar signal provided by an embodiment of this application.
  • FIG. 7 is a schematic diagram of a radar signal receiving process provided by an embodiment of this application.
  • FIG. 8 is a schematic diagram of another radar signal receiving process provided by an embodiment of this application.
  • FIG. 9 is a schematic diagram of another radar signal receiving process provided by an embodiment of this application.
  • 10(a) to 10(c) are schematic diagrams of a Doppler spectrum provided by an embodiment of the application.
  • FIG. 11 is a schematic diagram of a Doppler spectrum provided by an embodiment of this application.
  • FIG. 12 is a schematic diagram of a Doppler spectrum provided by an embodiment of this application.
  • FIG. 13 is a schematic diagram of a Doppler spectrum provided by an embodiment of this application.
  • FIG. 14 is a schematic diagram of a Doppler spectrum provided by an embodiment of this application.
  • FIG. 15 is a schematic diagram of a Doppler spectrum provided by an embodiment of the application.
  • FIG. 16 is a schematic diagram of a Doppler spectrum provided by an embodiment of the application.
  • FIG. 17 is a schematic structural diagram of a radar device provided by an embodiment of the application.
  • FIG. 18 is a schematic structural diagram of a radar device provided by an embodiment of this application.
  • FIG. 1(a) it is a schematic diagram of a radar device provided by an embodiment of this application.
  • the radar device in FIG. 1(a) may be a MIMO radar, and may include an antenna array 101, a microwave integrated circuit (monolithic microwave integrated circuit, MMIC) 102, and a processor 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 one or more transmitting antennas in the transmitting antenna array in the antenna array 101.
  • the waveform of the signal sent by the transmitting antenna of the radar device is FMCW, and its frequency is modulated by increasing and decreasing the frequency of the signal over time.
  • This signal usually includes one or more "chirps". (chirp) signal”.
  • ADC Analogy to Digital Converter
  • PLL Phase Locked Loop
  • the radio frequency link of each transmitting antenna in the radar device also includes a switch and a phase shifter.
  • the microwave integrated circuit may include one or more radio frequency receiving channels and radio frequency transmitting channels.
  • the radio frequency transmission channel may include modules such as a waveform generator, a phase shifter, a switch, and a power amplifier (PA).
  • the radio frequency receiving channel may include a low noise amplifier (LNA), a down mixer (mixer), a filter, and an analog to digital converter (analog to digital converter, ADC) and other modules.
  • LNA low noise amplifier
  • ADC analog to digital converter
  • Fig. 1(b) is only an example, and there may be other forms of microwave integrated circuits, which are not limited in the embodiment of the present application.
  • the processor Before transmitting the radar signal, the processor realizes the waveform of the configured radar signal through the waveform generator in the radio frequency transmitting channel.
  • the orthogonal transmit waveforms of the multiple transmit antennas in the embodiments of the present application may be pre-configured by the processor, and are not limited to the name of the processor, but only represent the function of realizing the pre-configured waveform.
  • the radar signal may be transmitted in a time-division manner in different transmitting antennas, so the transmitting antenna that needs to transmit the radar signal can be gated by a switch.
  • the radar signal may be code-divided and transmitted in different transmitting antennas, and the corresponding phase is modulated by a phase shifter connected to the transmitting antenna.
  • the switch and the phase shifter are serially connected to the antenna and the waveform transmitter, but the sequence of the switch and the phase shifter can be exchanged.
  • the microwave integrated circuit 102 is also used for mixing and sampling the echo signals received on part or all of the receiving antennas in the receiving antenna array in the antenna array 101, and transmitting the sampled echo signals to the processor 103.
  • the processor 103 is configured to perform Fast Fourier Transformation (FFT), signal processing and other operations on the echo signal, so as to determine the distance, speed, angle and other information of the target according to the received echo signal.
  • the processor 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(a) may also include an electronic control unit (ECU) 104, which is used to control the vehicle according to the target distance, speed, angle and other information processed by the processor 103. For example, determine the route of the vehicle, control the speed of the vehicle, and so on.
  • ECU electronice control unit
  • the transmitter in the embodiment of the present application may include a transmitting antenna and a transmitting channel in the microwave integrated circuit 102, and the receiver includes 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 in the chip package Inside, the transmitting channel and the receiving channel can be located in the chip, that is, an antenna in package (AIP).
  • 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 are connected to the data output by the analog digital converter (analog digital converter, ADC) channel through the interface.
  • ADC analog digital converter
  • MCU digital central processing unit
  • DSP digital signal processor
  • FPGA field-programmable gate array
  • GPU general processing unit
  • MMIC and DSP can be integrated in one chip, which is called System on Chip (SOC).
  • the MMIC and ADC, and the processor 103 can be integrated into 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 processor controls one or more on-board sensors, including one or more millimeter wave radar sensors.
  • the radar device shown in Figure 1(a) can be applied to a vehicle with an automatic driving function.
  • FIG. 2 is a functional block diagram of a vehicle 200 with an automatic driving function provided in an embodiment of the present application.
  • the vehicle 200 is configured in a fully or partially autonomous driving mode.
  • the vehicle 200 can simultaneously control itself in the automatic driving mode, and can determine the current state of the vehicle and its surrounding environment through human operations, determine the possible behavior of at least one other vehicle in the surrounding environment, and determine the other vehicle A confidence level corresponding to the possibility of performing a 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 may also be used to sense the speed and/or heading of the target. In a specific example, the radar 226 may be implemented by the radar device shown in FIG. 1(a).
  • 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.
  • 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 a target, estimate the speed of the target, 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 can 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 214.
  • 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.
  • some components such as the steering component and the deceleration component may each have its own processor, and the processor 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 214 may contain instructions 225 (e.g., 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 214 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 (for example, 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 these components described above may be installed or associated with the vehicle 200 separately.
  • the storage 214 may exist partially or completely separately from the vehicle 200.
  • the aforementioned components may be communicatively coupled together in a wired and/or wireless manner.
  • FIG. 2 should not be construed as a limitation to the embodiments of the present application.
  • An autonomous vehicle traveling on a road can recognize targets in its surrounding environment to determine the adjustment to the current speed.
  • the target can be other vehicles, traffic control equipment, or other types of targets.
  • each identified 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 vehicle 200 or a 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 considered to determine the speed of the vehicle 200, such as the lateral position of the vehicle 200 on the road on which it is traveling, the curvature of the road, and the proximity of static and dynamic targets.
  • 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 may 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 in the embodiment of the present application can be applied to various fields.
  • the radar system in the embodiment of the present application includes, but is not limited to, vehicle-mounted radar, roadside traffic radar, and unmanned aerial vehicle. radar.
  • this application provides a method for transmitting and receiving radar signals.
  • the method is applied to a radar device.
  • the radar device includes N transmitting antennas, where N>m, where m is an integer greater than or equal to 2. It should be understood that the specific structure of the radar device may be as shown in FIG. 1(a), or may not be limited to the specific structure of FIG. 1(a), which is not limited in this application.
  • the method includes:
  • Step 301 Transmit the first signal through one of the N transmitting antennas in S time slots.
  • the phase of the first signal is unchanged in S time slots.
  • the phase of the first signal in the phase of the first time slot in S time slots is Then the phases in other time slots are
  • the signal waveform of the first signal in the S time slots is FMCW.
  • Step 302 Send the second signal in at least one of a time division manner or a code division manner through m transmit antennas of the N transmit antennas in S time slots.
  • the signal waveform of the second signal in the S time slots is also FMCW, and the first signal and the second signal adopt different phase modulation codes.
  • Code division method means Code Division Multiple Access (CDM), or Doppler Division Multiplex (DDM) or Doppler Division Multiple Access (Doppler-Division Multiple Access, DDMA) through modulation
  • CDM Code Division Multiple Access
  • DDM Doppler Division Multiplex
  • DDMA Doppler-Division Multiple Access
  • the second signal is transmitted through m transmitting antennas, which is equivalent to a superposition of the signals transmitted by m transmitting antennas.
  • phase modulation is equivalent to the signal multiplied by exp(j ⁇ ), which has the characteristics of equivalent value after 2 ⁇ period rotation. Therefore, the actual system only uses P phases, and other phase modulations of integer multiples of 2 ⁇ can be achieved. That is, the phase modulation of 2 ⁇ /P can be used instead of the phase of 2 ⁇ /P+u*2 ⁇ , and u is an integer.
  • step 301 and step 302. since the second signal and the first signal both occupy S time slots for transmission, there is no sequence between step 301 and step 302. It only means that the first signal and the second signal use different code divisions, that is, different Doppler offset steps of 2 ⁇ k y /P are used for phase modulation, P is an integer greater than 1, and k y is greater than or equal to 0 and less than P Integer. When k y is equal to 0, it can be understood that the transmit antenna is in multiple time slots, that is, the signal change occupied by adjacent time slots is zero.
  • the first signal Since the first signal only includes the signal of one transmitting antenna and occupies S consecutive time slots, the first signal can be a SIMO signal, which has the advantage of a large speed measurement range.
  • the second signal includes the signal of m transmitting antennas, which can be understood as a TDM MIMO signal, and its advantage is that the measured angular resolution is relatively large. Since the target moves during measurement, the SIMO signal and TDM MIMO signal rely on matching the speed index on the same distance unit to obtain the target's non-aliasing speed. If the first signal and the second signal are not transmitted at the same time, the SIMO signal and MIMO signal transmitted before and after may cause the target to fail to match the same range unit, that is, the observation time of the target is different, and the target cannot be accurately measured. speed.
  • the first signal and the second signal are transmitted at the same time. Therefore, when the SIMO signal and TDM MIMO signal are transmitted in time division in the prior art, the observation time of the high-speed moving target is different, which makes it impossible to accurately measure the speed of the target. The problem.
  • the signal sent by each transmitting antenna is phase modulated with a step length of ⁇ , that is, the phase modulation code of each transmitting antenna in the second signal is the same, that is, [1, -1]. Therefore, in order to distinguish the orthogonal waveforms of the m transmitting antennas in the second signal, in the second signal, the m transmitting antennas further transmit the signal in a time division manner. Since TDM MIMO transmission is not restricted by phase control, the number of transmitting antennas of the radar system can be easily expanded through multiple transmitting antennas in the second signal, that is, m can be an arbitrary integer greater than or equal to 2.
  • This method solves the problem of the existing two-phase DDM waveforms that cannot achieve orthogonal transmission of more transmitting antennas.
  • the first signal is continuously transmitted in S time slots, ensuring the maximum speed range of the radar system. Avoid the use of TDM MIMO transmission to introduce the problem of reduced speed range of the radar system.
  • the first signal can also be phase modulated with a step size of ⁇ .
  • the signals of the multiple transmitting antennas in the second signal are all transmitted with a step length of 0, that is, they are transmitted in a phase-invariant manner.
  • the velocity measurement range of the first signal is relatively large, if the first signal adopts 0 step for phase modulation, the echo signal of the first signal at the receiving end can be obtained within a relatively large velocity measurement range, and there is no non-zero phase modulation step.
  • the additional Doppler shift caused by the long length further simplifies the receiving process. Therefore, in the embodiment of the present application, the following embodiments are described by taking the first signal to perform phase modulation with a step length of 0 as an example.
  • each of the m transmitting antennas performs repeated transmission with a period of P*M time slots.
  • P the second signal adopts multiple transmitting antennas with a step size of 2 ⁇ k y /P for phase modulation
  • P time slots are required to complete uniform Doppler modulation.
  • each transmitting antenna repeats transmission with a period of P*M time slots
  • one transmitting antenna transmits according to a transmission pattern in each cycle.
  • the transmission pattern indicates the relationship between the phase and amplitude of the signal being modulated, and it is transmitted in a time division manner.
  • the signal of the antenna occupies the non-conflicting P time slots with an interval of M time slots, M is the number of time slots between adjacent time slots in the time slots occupied by one of the m transmitting antennas, M It is an integer greater than or equal to m/(P-1).
  • Nd+1)*P*M>S> Nd*P*M
  • Nd represents m transmitting antennas with P*M time slots as the period, the number of transmission cycles, Nd is an integer greater than or equal to 1.
  • the specific value of M can be determined according to actual conditions, and satisfies that M is an integer greater than or equal to m/(P-1). It is stated here that S may not be equal to an integer multiple of Nd*P*M, and zero padding can be done at the receiving end, and there is no restriction here.
  • Nd is an integer greater than or equal to 1
  • M is an integer greater than 1
  • S is an integer greater than or equal to 4.
  • the specific value of S can be determined according to actual conditions and is not limited here.
  • the signals transmitted by each of the m transmitting antennas can be distinguished by time division or code division, that is, the signals transmitted by different transmit antennas occupy different time slots, or the signals transmitted by the m transmit antennas occupy the same time slot.
  • the signal sent by the transmitting antenna of the slot is phase modulated with a step length of 2 ⁇ k y /P, the value of k y is different. In this way, even if the number of P cannot be very large, for example, when P is less than or equal to 4, the signals of the N transmitting antennas can still be transmitted orthogonally.
  • the combination of the phases of the signals sent by a transmitting antenna in a cycle can be called the transmitting pattern of the transmitting antenna, then according to Euler’s formula That is, the phase of the signal of the transmitting antenna 1 in the 4 occupied time slots is cycled by 0, ⁇ /2, ⁇ , and 3 ⁇ /2 in turn, expressed as a complex number.
  • the transmitting antenna 1 occupies an interval in P*M time slots.
  • the phase in P time slots of M can be expressed as [1, j, -1, -j]; in the same way, the phase of transmitting antenna 2 can be expressed as [1, -j, -1, j].
  • the transmitting antenna that transmits the first signal is marked as Tx0
  • the transmitting antenna that transmits the second signal is marked as Tx1 to Txm.
  • the m transmitting antennas that transmit the second signal and the one transmitting antenna that transmits the first signal may be different transmitting antennas among the N transmitting antennas.
  • Tx0 sending the first signal occupies all of the S time slots.
  • the combination of the phases of the signals sent by one transmitting antenna in a period can be called the transmitting pattern of the transmitting antenna.
  • FIG. 4 a schematic diagram of a signal provided by an embodiment of this application.
  • the first signal is sent through the transmitting antenna Tx0.
  • the first signal includes S chirp signals, and the phase between each chirp signal is unchanged.
  • the second signal includes multiple chirp signals.
  • the second signal is transmitted in time division through the transmitting antenna Tx1 and the transmitting antenna Tx2.
  • the period of the signal sent by Tx1 and Tx2 is 4 time slots.
  • the transmission pattern of Tx1 in each period can indicate that the signal is modulated.
  • the relationship between the phase and amplitude of is [1,x,-1,x], and the signal of the transmission pattern of Tx2 in each cycle can represent the phase and amplitude relationship of the signal being modulated as [x,1,x,-1] .
  • x represents silence, no signal is sent in this time slot, or it can be represented by 0, that is, the transmission pattern of Tx1 in each cycle can be written as [1,0,-1,0], and the transmission of Tx2 in each cycle The pattern can be written as [0,1,0,-1].
  • the amplitude of the signal in this time slot is set to zero.
  • the actual system can be achieved by setting the switch to the off state; 1 means the chirp in this time slot The phase of the signal is modulated by 0 radians; -1 means that the phase of the chirp signal in the time slot is modulated by ⁇ radians. In the actual system, it can be achieved by setting the switch to the closed state and selecting the corresponding phase of the phase shifter.
  • the time slot occupied by the signal sent by Tx1 is different from the time slot occupied by the signal sent by Tx2; among the time slots occupied by the signal sent by Tx1, there are 2 time slots between adjacent time slots; Tx2 sent Among the time slots occupied by the signal, adjacent time slots are separated by 2 time slots.
  • the chirp signal shown in FIG. 4 is a rising linear continuous frequency modulation wave, and the chirp signal may also be a falling linear continuous frequency modulation wave, which is not limited in the embodiment of the present application.
  • the transmission pattern indicates that the signal of the transmitting antenna adopts the time division method, and the occupancy interval is M time slots without conflicting P time slots, and M is the interval between adjacent time slots among the time slots occupied by one of the m transmitting antennas.
  • the number of time slots separated, M is an integer greater than or equal to m/(P-1).
  • the specific value of M can be determined according to actual conditions, and satisfies that M is an integer greater than or equal to m/(P-1).
  • the first signal is transmitted in every time slot, and the transmission pattern of the transmitting antenna Tx0 that transmits the first signal can be written as 6 time slots, expressed as [1,1,1,1,1,1];
  • the transmission patterns of the multiple transmitting antennas of the signal are as follows:
  • the transmission pattern of Tx1 can be written as 6 time slots, expressed as [1,x,x,-1,x x], and the transmission pattern of Tx2 is expressed in 6 time slots. Is [x,1,x,x,-1,x], then only the transmit antenna signal in the first signal exists in the third and sixth time slots, and the signal of the second transmit antenna is in the first In time slot 3 and time slot 6, through switch gating control, no antenna is strobed.
  • the echo signals in the third and sixth time slots are extracted, and the observed Doppler frequency is the echo signal of the transmitting antenna signal in the first signal.
  • the Doppler frequencies in the second and fifth time slots in the first and fourth time slots include the echo signal of the transmitting antenna signal in the first signal and the second signal.
  • the size of Nd can be further restricted according to the requirements for resolution accuracy.
  • Each grid in the first row of Table 1 represents a time slot, and each grid in the first column represents a transmitting antenna.
  • the numbers of transmitting antennas in Table 1 are only logical numbers, and transmitting antennas with adjacent numbers do not represent actual spatial neighbor relationships.
  • the transmitting antenna of the first signal is denoted as Tx0, and a 0-phase modulation signal is adopted.
  • the step size modulates the signal.
  • the first signal in addition to simultaneously transmitting the first signal and the second signal in S time slots, in S0 time slots after S time slots, the first signal can also be transmitted in a time division manner through m transmitting antennas.
  • S0 is an integer greater than 1.
  • the Doppler frequency in the received echo signal in S0 time slots can be compared with S time slots.
  • the Doppler frequency in the received echo signal in the time slot determines the Doppler frequency of the target, and the Doppler index position corresponding to Tx0 in the S time slots is determined, which further simplifies the process of obtaining the target speed on the receiving side.
  • FIG. 5 it is a schematic diagram of a signal provided by an embodiment of this application.
  • the first signal and the second signal sent in the previous S time slots can be referred to as shown in FIG. 4.
  • the third signal is transmitted through Tx1 and Tx2.
  • the transmission pattern of the third signal is the same as that of the second signal, that is, the period of the signal sent by Tx1 and Tx2 is 4 time slots, and the signal of the transmission pattern of Tx1 in each period can indicate the phase and amplitude of the signal being modulated.
  • the relationship is [1,x,-1,x], and the signal of the transmission pattern of Tx2 in each cycle can indicate that the relationship between the phase and amplitude of the signal being modulated is [x,1,x,-1]. It can be seen from Figure 5 that the signal sent by Tx1 in S0 time slots is the same as the signal sent in S time slots, and the signal pattern sent by Tx2 in S0 time slots is the same as the signal sent in S time slots. same. Among them, x represents silence, no signal is sent in this time slot, or it can be represented by 0.
  • the amplitude of the signal in this time slot is set to zero, and the actual system can be realized by setting the switch to the off state; 1 It means that the phase of the chirp signal in this time slot is modulated by 0 radians; -1 means that the phase of the chirp signal in this time slot is modulated by ⁇ radians.
  • the switch can be set to the closed state and correspond to the phase shifter. Phase selection to achieve.
  • the time slot occupied by the signal sent by Tx1 is different from the time slot occupied by the signal sent by Tx2; among the time slots occupied by the signal sent by Tx1, there are 2 time slots between adjacent time slots; Tx2 sent Among the time slots occupied by the signal, adjacent time slots are separated by 2 time slots.
  • the first signal is sent through the transmitting antenna Tx0, the first signal includes S chirp signals, and the phase of each chirp signal remains unchanged.
  • the second signal is sent through the transmitting antenna Tx1 to the transmitting antenna Tx6, and the period of the signal sent by each transmitting antenna is 8 time slots.
  • the 6 transmitting antennas can be divided into 2 groups, one group includes Tx1, Tx2, and Tx3, and the other group includes Tx4, Tx5, and Tx6.
  • Tx1, Tx2, and Tx3 can occupy the same time slot, but use different phase modulation codes to send signals.
  • the signal of the transmission pattern of Tx1 in each cycle can indicate that the phase and amplitude relationship of the signal being modulated is [1,x,j,x,-1,x,-j,x], that is, the step size is ⁇ /2
  • the signal of the transmission pattern of Tx2 in each cycle can represent the phase and amplitude relationship of the signal being modulated as [1,x,-1,x,1,x,-1,x], that is, the modulation step is ⁇
  • the signal of the transmission pattern of Tx3 in each cycle can represent the phase and amplitude relationship of the signal being modulated as [1,x,-j,x,-1,x,j,x], that is, the modulation step is 3 ⁇ /2.
  • x means silence, no signal is sent in this time slot; 1 means that the phase of the chirp signal in this time slot is modulated by 0 radians; j means that the phase of the chirp signal in this time slot is modulated by ⁇ /2 radians ; -1 indicates that the phase of the chirp signal in the time slot is modulated by ⁇ radians; -j indicates that the phase of the chirp signal in the time slot is modulated by 3 ⁇ /2 radians.
  • Tx4, Tx5, and Tx6 in the first group and Tx1, Tx2, and Tx3 in the second group occupy different time slots to transmit signals, and they are divided and orthogonal in real time.
  • the signal of the transmission pattern of Tx4 in each cycle can represent the phase and amplitude relationship of the signal being modulated as [x,1,x,j,x,-1,x,-j], that is, the modulation step is ⁇ /2
  • the signal of Tx5 emission pattern in each cycle can represent the phase and amplitude relationship of the signal being modulated as [x,1,x,-1,x,1,x,-1], that is, the modulation step size Is ⁇
  • the signal of the transmission pattern of Tx6 in each cycle can represent the phase and amplitude relationship of the signal being modulated as [x,1,x,-j,x,-1,x,j], that is, the modulation step is 3 ⁇ /2.
  • the transmission pattern of the signal sent by Tx4 may be a cyclic shift sequence of the transmission pattern of the signal sent by Tx1.
  • a cyclic shift sequence may refer to a new sequence obtained by shifting a base sequence clockwise or counterclockwise. For example, if the base sequence is a cyclic shift sequence of [1,x,j,x,-1,x,-j,x], the sequence that can be obtained is [x,1,x, j,x,-1,x,-j]; according to the clockwise cyclic shift 2 times, the sequence that can be obtained is [j,x,-1,x,-j,x,1,x] and so on.
  • the signal sent by Tx5 may be the cyclic shift sequence of the signal sent by Tx2, and the signal sent by Tx6 may be the cyclic shift sequence pattern of the signal sent by Tx3.
  • the specific phase step size selected for each transmitting antenna in a group of antennas occupying the same time slot only needs to be different, and the present application does not limit the specific phase step size corresponding to the transmitting antenna sequence given in the embodiment.
  • Each grid in the first row of Table 2 represents a time slot, and each grid in the first column represents a transmitting antenna.
  • the numbers of transmitting antennas in Table 2 are only logical numbers, and transmitting antennas with adjacent numbers do not represent actual spatial neighbor relationships.
  • the transmitting antenna of the first signal is denoted as Tx0, and a 0-phase modulation signal is adopted.
  • the transmitting antennas of the second signal are denoted as Tx1 to Tx15.
  • the transmitting antenna of the signal is recorded as Tx0, using 0 phase modulation signal, [1,1,1,1,1,1,1,1,1,1,1,1,1,1,1 ,1] represents the modulated signal of 20 time slots;
  • the second signal is transmitted by time division or code division through Tx1 to Tx15 respectively, that is, the code division antenna adopts ⁇ /2, ⁇ , 3 ⁇ /2 as the step length modulation, and the time division antenna
  • Tx3 can be sent using different phase modulation codes, respectively.
  • the modulated signals of the 20 time slots sent are expressed as [1,x,x,x,x,j, x,x,x,x,-1, x,x,x,x,-j,x,x,x,x],[1,x,x,x,x,-1,x,x,x,x,x,1,x,x,x,x, x, x,-1,x,x,x,x],[1,x,x,x,-j,x,x,x,x,x,-1,x,x,x,x,x,j,x ,x,x,x].
  • Tx4 and Tx5, Tx6 and Tx1-Tx3 can use different time slots, for example, the phase encoding is Tx1-Tx3, which moves 1 time slot counterclockwise, and the modulated signals of 20 time slots sent are expressed as [x,1,x,x ,x,x,j,x,x,x,x,x,-1,x,x,x,x,x,-j,x,x,x],[x,1,x,x,x,x,- 1,x,x,x,x,x,1,x,x,x,x,x,-1,x,x,x],[x,1,x,x,x,x,-j,x,x, x,x,-1,x,x,x,x,x,x].
  • Tx7 ⁇ Tx9 The similar phase encoding of Tx7 ⁇ Tx9 is Tx1-Tx3 moving counterclockwise for 2 time slots
  • Tx10 ⁇ Tx12 phase coding is Tx1-Tx3 moving counterclockwise for 3 time slots
  • Tx13 ⁇ Tx15 phase coding is Tx1-Tx3 counterclockwise moving Move 4 time slots.
  • the m transmitting antennas that transmit the second signal use the same configuration to transmit the signal in the S time slots.
  • m transmit antennas may also be in the S time slot, the second signal m transmit antennas into different groups, or selection of different M i m i, i 1, taking at least two configurations.
  • the first signal is sent through the transmitting antenna Tx0, the first signal includes S chirp signals, and the phase of each chirp signal remains unchanged.
  • the second signal is sent through the transmitting antenna Tx1 to the transmitting antenna Tx2.
  • the transmission pattern of Tx1 in each cycle can indicate that the phase and amplitude of the signal are modulated as [1,x,-1,x].
  • the signal of the emission pattern can indicate that the phase and amplitude relationship of the signal being modulated is [x,1,x,-1].
  • the transmission pattern of Tx4 in each cycle can indicate that the phase and amplitude relationship of the signal is modulated as [1,x,x,-1,x,x], and the signal of the transmission pattern of Tx4 in each cycle can indicate that the signal is modulated.
  • phase and amplitude is [x,1,x,x,-1,x]
  • the period of the signal sent by Tx1 and Tx2 is 4 time slots, and is repeatedly transmitted Nd1 times.
  • Such a multi-configuration can avoid two targets whose velocities differ by half of the maximum velocity measurement range, in which the Doppler index of the echo signal of the Tx0 signal of target 1 just falls and the echo of the Tx1 and Tx2 signals modulated to the ⁇ phase of target 2 The Doppler index of the wave signal is the same.
  • the embodiment of the present application also provides a method for processing the echo signal formed after the first signal and the second signal are reflected by one or more targets, thereby Obtain the speed of one or more targets, and then obtain the angle information (for example, horizontal azimuth angle and vertical azimuth angle) of one or more targets.
  • the angle information for example, horizontal azimuth angle and vertical azimuth angle
  • the radar device includes N transmitting antennas and at least one receiving antenna.
  • the method includes the following steps:
  • Step 701 Receive an echo signal formed after the first signal and the second signal are reflected by at least one target.
  • the specific content of the first signal and the second signal can be referred to the flowchart shown in FIG. 3.
  • the echo signal formed after the first signal and the second signal are reflected by at least one target is received; among them, the first signal is transmitted through one of the N transmitting antennas in S time slots, and the phase of the first signal is It remains unchanged in S time slots; the second signal is transmitted through m transmitting antennas out of N transmitting antennas in S time slots using at least one of time division and code division; the second signal is transmitted through m transmission antennas
  • the signal sent by each of the transmitting antennas is phase modulated with a step length of 2 ⁇ k y /P, where P is an integer greater than 1, and k y is an integer greater than 0 and less than P, where k y represents the number of m transmitting antennas
  • Step 702 Obtain M sub-distance-Doppler maps (Range Doppler Map, RD Map) of each receiving antenna.
  • Each receiving antenna here refers to each receiving antenna among all receiving antennas included in the radar device.
  • the i-th sub-RD pattern in the M sub-RD patterns of each receiving antenna is the initial time slot of the echo signal of the receiving antenna in the S time slots, i, and the signal 2D-FFT of every M time slots As the result of, i takes any integer of 1, 2, ..., M.
  • Step 703 Detect the first target according to the accumulated sub-RD pattern of the M sub-RD patterns of each receiving antenna, and obtain the distance information of the first target.
  • the first target is one or more targets among at least one target.
  • the distance information of the first target can be obtained through the process shown in FIG. 7, and the angle information and speed information of the first target can also be obtained in the embodiment of the present application, which may be specifically as shown in FIG. 8.
  • Step 801 According to the difference frequency signal of the received echo signal, perform a one-dimensional fast Fourier transform (Fast Fourier Transformation, FFT) (1D-FFT) in each time slot, that is, the fast Fourier transform of the distance dimension Leaf transform.
  • FFT Fast Fourier Transformation
  • Nrx receiving antennas obtain multiple sampled signals in each time slot
  • the size of the distance dimension FFT is Nrange
  • Step 802 Based on the result of 1D-FFT, calculate one by one to extract the signals of every M time slots from 1 to M in each distance unit to do a two-dimensional FFT (2D-FFT), that is, multiple The Pule Fourier transform obtains the complex values of the M sub-RD patterns on the Nrx receiving antennas, thereby obtaining the M sub-RD patterns of each receiving antenna.
  • 2D-FFT two-dimensional FFT
  • RD graph one dimension is distance information, and one dimension is radar output graph of Doppler information. Extracting from the distance dimension is called the distance unit (Range bin), and extracting from the Doppler dimension is called the Doppler unit (Doppler bin). At the same time, extracting from the distance and Doppler dimensions is called the range-Doppler unit (Range-Doppler). Cell).
  • the following operations may also be performed on the echo signal, such as signal windowing (Windowing), send/receive channel calibration (Tx/Rx Calibration), zero-padding (Zero-padding) ), etc.
  • the embodiments of the present application do not impose limitations. For details, reference may be made to the description in the prior art, which will not be repeated here.
  • the first target may be detected according to the M sub-RD patterns of each receiving antenna, and the distance information of the first target may be obtained, which may specifically include the following step:
  • Step 803 Accumulate the M sub-RD patterns obtained on the multiple receiving antennas, obtain the accumulated sub-RD patterns, and perform detection on the accumulated sub-RD patterns to obtain the distance index Rind of the first target, which is the distance index of the first target Distance information.
  • the distance index Rind and the Doppler index Vind of the first target are obtained, and Vind is the Doppler index of the detected target within the range of [1, Nfft/P].
  • Target detection is performed according to the coherent cumulative value or incoherent cumulative value of the M sub-RD patterns of Nrx receiving antennas.
  • the coherent accumulation value is a value of in-phase superposition for the signal accumulation mode of different transmitting antennas or receiving antennas, that is, the maximum value in the predetermined angle beam direction is selected.
  • the signal accumulation method of different transmitting antennas or receiving antennas adopts the value of amplitude superposition.
  • Threshold detection can be performed in the distance dimension, here is not limited to using Constant False-Alarm Rate (CFAR) to obtain the distance index Rind of the first target, and other detection methods, such as noise threshold-based methods, etc. .
  • CFAR Constant False-Alarm Rate
  • Step 804a Perform 2D-FFT using all S time slots in the Doppler domain to obtain a complex value of a total range-Doppler map (range doppler map, RD Map).
  • the dimension of the total RD graph is Nrange*(M*Nfft), that is, the distance dimension is the same as the dimension of the sub-RD graph, and the Doppler dimension is M times the sub-RD graph.
  • the total RD pattern is based on step 801 using all S time slots in the Doppler domain to perform 2D-FFT of M*Nfft points, and no M interval extraction is performed. Only Nrx receiving antennas are superimposed incoherently.
  • step 804a can be replaced with step 804b: calculate the 2D-FFT Doppler spectrum in S time slots on the distance index Rind of the first target detected in the sub-RD graph .
  • Step 805 Determine at least one Doppler index Vind_sub of the aliasing speed of the first signal in the accumulated sub-RD image of the first target, that is, obtain the Doppler index Vind_sub of the Tx0 in the accumulated sub-RD image.
  • the Doppler index Vind_sub of the first signal of the first target on the accumulated sub-RD image is one of P possible positions with an interval of Nfft/P, where Nfft is the dimension of the 2D-FFT of the accumulated sub-RD image.
  • the distance unit Rind of the first target extracts the Doppler value from the sub-RD graph for detection, that is, the Doppler domain performs threshold detection to obtain the speed of the first target within the range of aliasing Vmax/M, or the first signal At least one Doppler index Vind_sub of the speed of aliasing.
  • At least one Doppler index Vind_sub of the aliasing velocity of the first signal on the accumulated sub-RD pattern of the first target cannot be directly obtained, but is located in P spectral lines separated by Nfft/P, and P spectra
  • the line includes Vind, Nfft/P+Vind,..., (P-1)Nfft/P+Vind, where Nfft is the 2D-FFT dimension of the accumulated sub-RD graph, and Vind is in the range of [1, Nfft/P]
  • the target index value detected within is mapped to Physical channels.
  • the specific detection here can also detect any sub-range of the P sub-intervals of the accumulated sub-RD pattern. For example, if you select Vind in the interval [Nfft/P+1, 2Nfft/P], then the positions of the corresponding P spectral lines are Vind-Nfft/P, Vind,..., (P-2)Nfft/P+Vind.
  • the embodiment of the present application proposes a variety of methods for determining the position of the spectral line Tx0, one of which is the method in step 805, which uses only the information of the M sub-RD patterns. Another method can use the total RD graph and the sub RD graph, and refer to step 806 for details.
  • the method in step 805 only use M sub-RD patterns. Specifically, compare the amplitude difference of a pair of spectral lines corresponding to P spectral lines in each sub-RD pattern of the same receiving antenna, and the sub-RD pattern corresponding to a pair of spectral lines with a smaller amplitude difference is The position of the spectral line where Tx0 is located is to determine the Doppler index corresponding to the Tx0 antenna in the sub-RD map.
  • Tx1 to Txm are respectively m transmitting antennas for transmitting the second signal.
  • Step 806 Extract the complex values of the P spectral lines in each sub-RD image one by one, this P spectral line is the Doppler index value of the sub-RD image Vind, Nfft/P+Vind...(P-1)Nfft/
  • Vind is the target index value detected in the range of [1, Nfft/P].
  • the corresponding spectral line of Tx0 on the accumulated sub-RD pattern and the corresponding spectral line on the total RD pattern can be determined. That is to say, the speed of the first target is determined, and the corresponding speed of Tx0 on the accumulated sub-RD graph is also determined.
  • Vind can take a positive or negative number to indicate whether the target is far away or close.
  • the first target is any one of at least one target.
  • the index value also needs to be converted to the speed index value within the range of Vmax.
  • the Doppler index of the non-aliasing velocity of the first target Vind_total Vind_sub+kk*Nfft-Nfft/2, where kk represents the Doppler index after each M downsampling of the total RD image because the sub-RD image is
  • the alias value of kk is 0,...,M-1.
  • Vind_sub in the sub RD has performed an fftshift operation through -Nfft/2, which indicates positive and negative speeds
  • Vind_total in the total RD can obtain positive and negative speeds through the fftshift operation. Since different applications have different definitions of positive and negative speeds, the embodiments of the present application do not make limitations.
  • the sub-RD graph is used to obtain the number of targets on the distance unit, the spectral line with the highest energy on the same distance unit on the total RD graph, that is, the Doppler index Vind_total of the non-aliasing velocity of the first target,
  • the position of the Doppler index Vind_sub mod(Vind_total, Nfft)+Nfft/2 matching the velocity of the aliasing on the sub-RD map.
  • the number iterate the spectrum and the target number in turn.
  • the Tx0 spectral line of a target is higher than the spectral line energy of other transmitting antennas of the same target.
  • the Doppler spectrum corresponding to a 3 transmitting antenna is illustrated.
  • Figure 10(a) shows the Doppler spectrum of all time slots, that is, the total RD pattern.
  • Figure 10(b) shows the Doppler spectrum corresponding to time slot 1 and time slot 3.
  • Figure 10(c) shows the Doppler spectrum corresponding to time slot 2 and time slot 4.
  • the total RD pattern is used to detect the There are (P-1)*M+1 corresponding Doppler spectral lines. It is very difficult to directly detect the aliasing speed of a target on Tx0 on the total RD pattern.
  • the speed measurement range of the sub-RD graph is reduced to 1/M of the total RD graph, there are always P spectral lines with larger amplitudes with a difference of Nfft/P relationship, and the number of spectral lines in the sub-RD graph will not change with number of transmit antennas of the second signal increases, the number of different phase modulation step k y values and phase modulation using only concerned.
  • using the sub-RD map to determine at least one Doppler index Vind_sub of the aliasing velocity of a target only needs to match P spectral lines with larger amplitude, which is much smaller than the Doppler spectrum that needs to be matched in the total RD map. Number of lines.
  • Step 807 According to the Doppler index Vind_sub of the aliasing velocity in the accumulated sub-RD image of the Tx0, match the total RD image to obtain the Doppler index Vind_total of the non-aliasing velocity of the first target.
  • the total RD map corresponds to the Doppler index value with the largest possible amplitude, so as to obtain the Doppler index Vind_total of the non-aliasing velocity of the first target, where kk is the aliasing velocity coefficient, and kk takes the value 0,1, ..., M-1.
  • the non-aliasing speed of the first target is the speed information of the first target.
  • Steps 805 to 807 are repeatedly executed according to the multiple distance units where at least one target is detected until the traversal is completed.
  • Step 808 Obtain the 2D-FFT transformed complex signal of the transmitting antenna Tx0 on different receiving antennas.
  • the complex signal is extracted from the RD unit corresponding to the distance index Rind of the M sub-RD patterns of the Nrx receiving antennas and the Doppler index Vind_sub of the aliasing velocity.
  • Step 809 Compensate the Doppler phase deviation caused by the time division of the m transmitting antennas Tx1 to Txm and the phase deviation caused by the code division, and obtain the complex signal after the 2D-FFT transformation of the m transmitting antennas Tx1 to Txm on different receiving antennas.
  • m 0,1...M-1, for the first time slot, m takes 0, only the Doppler phase deviation caused by time division or the phase deviation caused by code division. When m takes other values, there is a Doppler phase deviation caused by time division and a phase deviation caused by code division.
  • f(V ind_total ) represents the complex value of the RD unit whose index of 2D-FFT on the total RD graph is (Rind, Vind_total) if the antenna is aligned to the transmission time and phase of Tx0
  • f(V ind_sub ) represents the first Transmit in m time slots, using For a phase-modulated antenna, a signal whose velocity aliasing coefficient is kk, is the complex value of the RD unit indexed as (Rind, Vind_sub) on the m-th sub-RD pattern.
  • the phase compensation amount introduced by the antenna transmitted in the TDM time-division time slot m and the velocity aliasing coefficient is And the change caused by phase modulation Among them, k m is the value of k in the phase modulation step length adopted by the transmission waveform adopted by the transmitting antenna in the m time slot.
  • the separated complex signal of each receiving antenna can be obtained after phase compensation.
  • Method 9-1 Determine the Doppler compensation value of the transmitting antenna at different times according to the phase difference of the spectral line phase where Tx0 is located in the N-1 sub-RD images.
  • Method 9-2 According to the obtained Doppler phase of the first target, the corresponding phase difference is compensated to the Doppler compensation value of the transmitting antenna at different moments.
  • the phase that needs to be compensated can be represented by Vind_sub or Vind_total.
  • Step 810 Obtain the angle information of the first target according to the signals on the virtual receiving antennas formed by different transmitting antennas and receiving antennas after compensation.
  • the antenna obtained by combining the transmitting antenna and the receiving antenna is a virtual receiving antenna (Virtual Receiver antenna), which can also be described as a virtual receiving array obtained by combining the transmitting antenna and the receiving antenna.
  • Virtual Receiver antenna Virtual Receiver antenna
  • the layout of the virtual receiving antenna it is not limited to using FFT or digital beamforming (digital beamforming, DBF) or multiple signal classification (Multiple Signal Classification, MUSIC) or other common angle spectrum analysis algorithms to obtain the angle information of the first target. This will not be repeated here.
  • step 810 the distance information and speed information determined in step 807 can also be obtained.
  • steps 808 to 810 will be repeatedly executed on the first target output in step 807.
  • FIG. 11 it is a schematic diagram of the Doppler spectrum line of a target contained in a distance unit in the total RD map.
  • 4 transmitting antennas require at least 6 time slots, and the total RD diagram includes 4 spectral lines;
  • 5 transmitting antennas require at least 8 time slots ,
  • the total RD pattern includes 5 spectral lines; in the total RD pattern on the far right of Fig. 11, 6 transmitting antennas require at least 10 time slots, and the total RD pattern includes 6 spectral lines.
  • Other situations will not be repeated.
  • the sub-RD pattern is used to detect the target, which can simplify the processing on the receiving side.
  • FIG. 12 it is a schematic diagram of two target Doppler spectrum lines contained in one distance unit in the total RD of two-phase 16 time slots.
  • the peak interval is 13
  • the Doppler index of the second peak of the total RD pattern does not satisfy the integer aliasing relationship of the interval
  • the third largest peak Doppler index of the amplitude is 659
  • matching 96-83 (544-659 )+2*128, so the speed at which the second target exists is 659*dv.
  • the example here is based on the same distance index Rind, there are two targets.
  • the embodiment of the present application is not limited to this, and multiple iterations can be performed until the matching peak value is lower than the predetermined threshold.
  • method 9-1 or 9-2 compensates the Doppler phase difference between different antennas according to the speed compensation caused by the Doppler phase difference at different times.
  • the signals of the antennas transmitted at different times are transmitted at the same time, and the phase difference on the antenna is only the phase difference introduced by the spatial time delay of the antenna. According to the phase difference, the angle information of the target is calculated. Since the calculation here is related to the antenna array, there is no special restriction here.
  • step 806 when the third signal is included in the S0 time slots after the S time slots, the steps performed by the corresponding receiving side are the same except for step 806. The details are You can refer to the previous description.
  • the foregoing step 806 can be implemented in the following manner:
  • the Doppler of Tx0 in the sub-RD graph can be determined. Le position, namely the Doppler index Vind_sub of the aliasing velocity, and the target real velocity, the corresponding Doppler index Vind_total of the non-aliasing velocity.
  • FIG. 13 is a schematic diagram of a Doppler spectrum line provided by an embodiment of this application.
  • Figure 13 (c) (bottom left in Figure 13) can obtain a total of 9 spectral lines, the signal sent by Tx0, and other multiple aliased spectral lines appearing on the spectral lines from Tx1 to Tx8 due to time division.
  • the target velocity, the Doppler phase corresponding to the target velocity, will not be repeated here.
  • step 806 and step 809 are described below respectively.
  • the phases of the transmitting antennas Tx1, Tx2, and Tx3 that simultaneously transmit signals in the same group are f0-(2* ⁇ *ii+Q)/(2* ⁇ *M*T SIMO ), and f0 is the frequency of the signal sent by Tx0.
  • the other channels are all time-divided, so the amplitude difference is relatively large.
  • Method 2 Use the total RD graph and the sub RD graph, that is, step 806.
  • Use the sub-RD graph to obtain the number of targets on the distance unit, and use the spectral line with the highest energy on the same distance unit on the total RD graph, that is, the Doppler index Vind_total of the non-aliasing velocity, which is matched on the sub-RD graph
  • FIG. 14 it is a schematic diagram of a Doppler spectrum provided by an embodiment of this application.
  • Figure 14 illustrates the total RD pattern and the Doppler spectrum of the sub-RD pattern of a target in a range unit with 4 phases and 8 time slots.
  • the total radial velocity is 0 as an example, and the case where there is only one target in the 0 degree direction is taken as an example for description.
  • There are 7 spectral lines separated by Nfft/4 64 in the total RD graph.
  • Each target has 4 spectral lines separated by 64 in the sub-RD pattern.
  • step 809 Compensate the Doppler frequency difference of the time slot where Tx1 to Txm are located, and the fixed phase difference j, -1, and -j between Tx0 and Tx0. Obtain the complex signals of Tx1 ⁇ Txm antennas after 2D-FFT transformation on different receiving antennas.
  • the example of the third embodiment can also be extended to the case where M is another value, for example, N ⁇ (P-1)*M+1.
  • M is another value, for example, N ⁇ (P-1)*M+1.
  • step 805 can be as follows:
  • the signal transmitted in each cycle of the first signal occupies P*M time slots in P time slots of interval M
  • the phase can be expressed as [1,1,1 ,1]
  • the signal sent in each cycle of the second signal occupies P*M time slots in P time slots of interval M
  • FIG. 15 it is a schematic diagram of the total RD pattern and the Doppler spectrum line of the sub-RD pattern with overlapping targets in the two sub-RD patterns in a distance unit with 2 phases and 4 time slots.
  • the signal transmission method in the fourth embodiment may be employed, i.e., the second signal m transmit antennas into different groups, or selection of different M i m i.
  • the previous steps 803, 806, and 809 may have the following differences:
  • Step 803 Extract multiple sub-RD patterns according to M1 and M2 respectively.
  • FIG. 16 illustrates a schematic diagram of the total RD pattern and Doppler spectrum lines of the target with Doppler overlap in 4 time slots in 2 sub-RD patterns in a distance unit with 2 phases and 6 time slots.
  • Step 806 Determine the spectral line where Tx0 is located according to a plurality of sub-RD patterns of different configurations and the total RD pattern.
  • Step 809 Compensate the Doppler frequency difference of the time slot where Tx1 to Txm are located.
  • N1 transmitting antennas and N2 transmitting antennas are used to transmit signals in a time division manner.
  • N1 transmitting antennas and N2 transmitting antennas are used to transmit signals in a time division manner.
  • the designed total transmission time of N1 and N2 meets the requirements of the target moving at the maximum speed and does not exceed one distance unit.
  • N1 transmitting antennas and N2 transmitting antennas The target reflected by the signal sent by the transmitting antenna is still in a range unit. Therefore, only the phase difference can be considered.
  • the total duration of the S1 time slots of the N1 transmitting antennas to transmit signals does not exceed 10ms
  • the total duration of the S2 time slots of the N2 transmitting antennas to transmit signals does not exceed 10ms.
  • the embodiment of the present application also provides a radar device, which can be used to execute the method shown in FIG. 3.
  • the radar device includes an antenna array 1701, a microwave integrated circuit 1702, and a processor 1703.
  • the antenna array 1701 includes N transmitting antennas, where N is an integer greater than 2, where:
  • the processor 1703 is configured to determine the first signal and the second signal
  • the microwave integrated circuit 1702 is used to generate the first signal and the second signal determined by the processor 1703;
  • the antenna array 1701 is used to transmit the first signal through one of the N transmitting antennas in S time slots; the phase of the first signal is unchanged in the S time slots; and the first signal is transmitted through N in the S time slots.
  • the m transmitting antennas of the transmitting antennas use at least one of the time division mode or the code division mode to transmit the second signal; S is an integer greater than or equal to 4; m is an integer greater than 2 and less than N; the second signal
  • the signal transmitted through each of the m transmitting antennas is phase modulated with a step size of 2 ⁇ k y /P, where P is an integer greater than 1, and k y is an integer greater than 0 and less than P, where k y represents m
  • the phase modulation step size adopted by the y-th transmitting antenna in the root transmitting antenna, y 1,...,m.
  • Nd+1)*P*M>S> Nd*P*M, where Nd represents the number of repetitions of the transmission pattern of m transmitting antennas, and Nd is greater than or equal to 1;
  • the transmission pattern represents the signal of the transmitting antenna using the time division method, which occupies P time slots with no conflicts with an interval of M time slots, and M is one of the adjacent time slots in the time slots occupied by one of the m transmitting antennas.
  • the number of time slots between each other, M is an integer greater than or equal to m/(P-1).
  • the signal m transmit antennas occupy the same time slot of the transmit antennas using 2 ⁇ k y / P step of phase modulation, different k y values.
  • the microwave integrated circuit is also used for: in the S0 time slots after the S time slots, the third signal is transmitted in a time division manner through m transmitting antennas, and S0 is an integer greater than 1; the third signal is in the S0
  • the microwave integrated circuit is specifically used for:
  • the period is P*M1 time slots, and the non-conflicting interval is selected among the P*M1 time slots of a period.
  • the P time slots of M1 respectively send the second signal;
  • the last S2 time slots of the S time slots, through the N2 transmitting antennas of the m transmitting antennas except for the N1 transmitting antennas, the P*M2 time slots are used as Cycle, in the P*M2 time slots of a cycle, select non-conflicting P time slots separated by M2 to send the second signal respectively;
  • P 2, 3, or 4.
  • the m transmitting antennas that transmit the second signal and the one transmitting antenna that transmits the first signal are different transmit antennas among the N transmit antennas.
  • the embodiment of the present application also provides a radar device, which can be used to execute the method shown in FIG. 7.
  • the radar device includes a radar device including a receiver 1801 and a processor 1802, and the receiver includes at least one receiving antenna, wherein:
  • the receiver is used to receive the echo signal, the echo signal is formed after the first signal and the second signal are reflected by at least one target; wherein, the first signal passes through one of the N transmitting antennas in S time slots The phase of the first signal is unchanged in the S time slots for transmission by the transmitting antenna; the second signal is transmitted through m of the N transmitting antennas in the S time slots, using at least one of time division and code division.
  • Sending m is an integer greater than or equal to 2 and less than N; the second signal is phase modulated with a step of 2 ⁇ k y /P for the signal sent through each of the m transmitting antennas, and P is greater than 1.
  • the processor is used to obtain M sub-distance-Doppler RD patterns of each receiving antenna in at least one receiving antenna; among them, the i-th sub-RD pattern of the M sub-RD patterns of each receiving antenna is that the receiving antenna is in S
  • the starting time slot in the echo signal of the time slots is i respectively, and the result of the two-dimensional fast Fourier transform 2D-FFT of the signal of every M time slots, i takes any integer of 1, 2, ..., M;
  • the first target is detected according to the sub-RD pattern accumulated by the M sub-RD patterns of each receiving antenna, and the distance information of the first target is obtained; the first target is one or more targets among at least one target.
  • the processor is further configured to: obtain a corresponding total distance-Doppler RD pattern, where the total RD pattern is the result of performing 2D-FFT on all adjacent time slots in the S time slots.
  • the processor is further configured to: determine at least one Doppler index Vind_sub of the aliasing speed of the first signal on the accumulated sub-RD map of the first target, and the first target is on the accumulated sub-RD map At least one Doppler index Vind_sub of the aliasing velocity of the first signal is located in P possible positions of the interval Nfft/P, where Nfft is the dimension of the 2D-FFT of the accumulated sub-RD image.
  • the processor is further configured to: perform matching according to the accumulated sub-RD pattern and the total RD pattern, determine at least one Doppler index Vind_total of the non-aliasing speed of the first target, and the first target after the accumulation At least one Doppler index Vind_sub of the corresponding aliasing velocity on the sub-RD map.
  • the processor is further configured to: compensate the Doppler phase deviation caused by the time division of the m transmitting antennas and the phase deviation caused by the code division, and obtain the angle information of the first target.
  • this application can be provided as a method, a system, or a computer program product. Therefore, this application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, this application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, optical storage, etc.) containing computer-usable program codes.
  • These computer program instructions can also be stored in a computer-readable memory that can direct 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.

Landscapes

  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)

Abstract

一种雷达信号发射和接收方法及装置，应用于雷达装置。雷达信号发射方法包括：S个时隙中发送第一信号以及第二信号；第一信号的相位在S个时隙中不变，可以相当于是一种SIMO信号；第二信号采用时分方式或码分方式中的至少一种方式发送；第二信号中通过m根发射天线中的每根发射天线发送的信号采用2πky/P的步长进行相位调制，相当于是一种MIMO信号。其中，P＝2时，MIMO信号采用时分方式发送，P>2时，MIMO信号采用时分方式和码分方式发送。该方法中，由于在S个时隙中同时发送第一信号和第二信号，因此通过第一信号和第二信号检测目标所需的时长明显减少，可以提高检测效率。

Description

一种雷达信号发射和接收方法及装置 技术领域
本申请涉及雷达技术领域，特别涉及一种雷达信号发射和接收方法及装置。
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，车载雷达可以发送调频连续波(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；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。由于获得目标角度需要分离多根发射天线的信号，因此，需要设计多发射天线的正交波形。
MIMO雷达多根发射天线可以采用时分复用(time division multiplexing，TDM)的方式发送啾啾(chirp)信号，以达到扩展虚拟天线口径的作用，即TDM MIMO波形。但TDM MIMO波形中存在最大测速范围Vmax_MIMO下降，Vmax_MIMO＝Vmax_SIMO/Ntx，其中Ntx为发射天线的数量。
另外，也有采用码分多址(Code Division Multiple，CDM)同时发射多根发射天线的信号，CDM也有文献称为多普勒复用制式(Doppler Division Multiplex，DDM)或多普勒分多址(Doppler-Division Multiple Access，DDMA)。文献《Automotive Fast-Chirp MIMO Radar with Simultaneous Transmission in a Doppler-Multiplex,The 19th International Radar Symposium IRS,2018》中利用二相位(binary phase)实现了2发射天线的MIMO雷达。而文献《Automotive Radar Doppler Division MIMO With Velocity Ambiguity Resolving Capabilities，16th European Radar Conference(EuRAD),2019》中利用二相位实现了3根发射天线的同时发射。这两种方式受限芯片中移相器对信号相位的精确控制，无法实现更多的天线正交发射，从而无法同时实现对测速范围和角度分辨率的需求。
发明内容
本申请的目的在于提供一种雷达信号发射和接收方法及装置，克服现有的雷达装置发送的正交波形无法同时实现对测速范围和角度分辨率的需求的问题。
第一方面，本申请提供一种雷达信号发射方法，应用于雷达装置，雷达装置包括N根发射天线，N为大于2的整数，m为大于或等于2的整数且小于N，方法包括：在S个时隙中同时发送第一信号和第二信号；其中第一信号通过N根发射天线中的1根发射天线发送；第一信号的相位在S个时隙中不变；第二信号在S个时隙中通过N根发射天线中的m根发射天线采用时分方式或码分方式中的至少一种方式发送，第二信号中通过m根发射天 线中的每根发射天线发送的信号采用2πk y/P的步长进行相位调制，P为大于1的整数，k y为大于0且小于P的整数，其中k y表示m根发射天线中的第y个发射天线采用的相位调制步长，y＝1,…,m。
上述方法中，由于第一信号中仅包括一根发射天线的信号，占用S个连续时隙，因此，第一信号可以是一种SIMO信号，其优点是测速范围较大。而第二信号中包括m根发射天线发送的信号，可以理解为是一种MIMO信号，其优点是测量的角度分辨率较大。通将上述第一信号和第二信号采用时分方式或码分方式中的至少一种方式发射，可以同时获得较大的测速范围和角度分辨率。
在一种可能的设计中，S可以存在一个取值范围，即(Nd+1)*P*M>S>＝Nd*P*M，其中Nd表示m根发射天线的发射样式的重复次数，Nd大于或等于1，发射样式表示采用时分方式的发射天线的信号占用间隔为M个时隙的不冲突的P个时隙，M为m根发射天线中一根发射天线占用的时隙中的相邻时隙之间相隔的时隙数量，M为大于或等于m/(P-1)的整数。其中，通过发射样式可以表示P*M个时隙中信号被调制的相位和幅值关系；根据P、Nd以及M的取值范围可知，即P＝2，m＝2，M＝m/(P-1)＝2，Nd＝1，可以得出S的最小值可以为4。
上述方法中，由于测量目标的速度的速度分辨率为λ/(2*S*Tchip)，与S的大小成反比，S越大，速度分辨率越小，获得目标的速度越准确。λ为调制频率的波长，Tchip为一个时隙的持续时间。
在一种可能的设计中，m根发射天线中占用相同时隙的发射天线发送的信号采用2πk y/P的步长进行相位调制时，k y取值不同。例如一根发射天线采用2π/P的步长进行相位调制，另一根发射天线采用4π/P的步长进行相位调制。
上述方法中，占用相同时隙的发射天线采用不同的步长进行相位调制，可以实现通过相位区分不同发射天线发送的信号，提高目标检测的准确率。
在一种可能的设计中，P个相位由包括[0，2π/P，4π/P，6π/P,…,(P-1)*2π/P]相位的移相器产生。
在一种可能的设计中，在S个时隙之后的S0个时隙中，还可以通过m根发射天线采用时分方式发送第三信号，S0为大于1的整数。第三信号的波形和第二信号的波形相同，即第三信号在S0个时隙中的发射样式和第二信号在S个时隙中的发射样式相同，S＝Nd*P*M，M为大于或等于m/(P-1)的整数。
上述方法中，通过在第一信号之后发送S0个时隙的第三信号，可以结合第一信号的速度分辨率获得目标的速度，和目标的速度对应的多普勒相位。
在一种可能的设计中，在S个时隙中通过N根发射天线中的m根发射天线采用时分方式或码分方式中的至少一种方式发送第二信号，包括：在S个时隙中的前S1个时隙，通过m根发射天线中的N1根发射天线以P*M1个时隙为周期，在一个周期的P*M1个时隙中选择不冲突的相隔M1的P个时隙分别发送第二信号；在S个时隙中的后S2个时隙，通过m根发射天线中除N1根发射天线之外的N2根发射天线以P*M2个时隙为周期，在一个周期的P*M2个时隙中选择不冲突的相隔M2的P个时隙分别发送第二信号；其中，m＝N1+N2，N1>＝2，N2>＝1；S＝S1+S2，M1≠M2，M1>＝N1/(P-1)，M2>＝N2/(P-1)。
上述方法中，上述方法中，由于配置的M1和M2不同，因此，最大测速范围不同，当在间隔为M1回波速度混叠的两个目标，在间隔为M2的回波中，可以很容易区分。反 之亦然，在间隔为M2的回波中速度混叠的两个目标，在间隔为M1的回波中可以很容易的区分。因此，通过设置不同的时隙间隔M1和M2，更容易确定实际目标数，避免遗漏反射的回波较弱的目标。
在一种可能的设计中，第一信号在S个时隙中的信号波形可以为FMCW；第二信号在S个时隙中的信号波形也可以为FMCW。或者，也可以采用其他MIMO雷达所使用的波形，例如，还可以为脉冲波形或正交频分复用(Orthogonal Frequency Division Multiplex，OFDM)等波形。
在一种可能的设计中，P＝2、3或4。
上述方法中，第一信号和第二信号分别采用了不同相位调制编码，并且只用到小于等于4相位，对相位调制器的精度要求降低，降低了对芯片的要求。
在一种可能的设计中，发送第二信号的m根发射天线与发送第一信号的1根发射天线之间的交集为0，即发送第二信号的m根发射天线与发送第一信号的1根发射天线为N根发射天线中不同的发射天线。
第二方面，本申请提供一种雷达信号接收方法，应用于雷达装置，雷达装置包括N根发射天线以及至少一根接收天线，m为大于或等于2的整数，且小于N，N大于2的整数，方法包括：获得至少一根接收天线中每根接收天线的M个子距离-多普勒RD图；根据每根接收天线的M个子RD图累积后的子RD图检测第一目标，并获得该第一目标的距离信息；第一目标为至少一个目标中的一个或多个目标。其中每根接收天线的M个子RD图中的第i个子RD图，为接收天线在S个时隙的回波信号中起始时隙分别为i，每隔M个时隙的信号二维快速傅里叶变换2D-FFT的结果，i取1,2,…,M的任意整数；回波信号是第一信号和第二信号经至少一个目标反射后形成的；其中，第一信号在S个时隙中通过N根发射天线中的1根发射天线发送，第一信号的相位在S个时隙中不变；第二信号在S个时隙中通过N根发射天线中的m根发射天线采用时分和码分方式中的至少一种方式发送；第二信号中通过m根发射天线中的每根发射天线发送的信号采用2πk y/P的步长进行相位调制，P为大于1的整数，k y为大于0且小于P的整数，其中k y表示m根发射天线中的第y个发射天线采用的相位调制步长，y＝1,…,m。
现有技术中，采用总RD图检测一个目标的混叠的速度的多普勒谱线，需要匹配的多普勒谱线有(P-1)*M+1个。而上述方法中，采用累积后的子RD图检测一个目标，由于同一个目标的对应的多普勒谱线只有P个，远小于采用总RD图检测时对应的多普勒谱线数量，因此，采用子RD图比总RD图更容易检测一个目标的混叠的速度的多普勒谱线。
需要说明的是，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距离单元(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)。
在一种可能的设计中，还可以获得总RD图，总RD图可以为在S个时隙内全部相邻时隙上执行二维FFT(2D-FFT)的结果。
在一种可能的设计中，方法还包括：确定第一目标在累积后的子RD图上第一信号的混叠的速度的至少一个多普勒索引Vind_sub，第一目标在累积后的子RD图上第一信号的混叠的速度的至少一个多普勒索引Vind_sub位于间隔Nfft/P的P个可能位置中，其中Nfft是累积后的子RD图的2D-FFT的维度。
在一种可能的设计中，方法还包括：根据累积后的子RD图和总RD图进行匹配，确 定第一目标的不混叠的速度的至少一个多普勒索引Vind_total，和第一目标在累积后的子RD图上对应的混叠的速度的至少一个多普勒索引Vind_sub。
在一种可能的设计中，方法还包括：补偿m根发射天线时分引起的多普勒相位偏差和码分引起的相位偏差，并且获得第一目标的角度信息。通过对相位偏差进行补偿，可以获得较准确的角度信息。
第三方面，提供一种雷达装置，雷达装置包括天线阵列、处理器和微波集成电路，天线阵列包括N根发射天线，N为大于2的整数，其中：
处理器，用于确定如第一方面任一种可能的设计中的第一信号和第二信号；
微波集成电路，用于生成处理器确定的第一信号和第二信号；
天线阵列，用于发送微波集成电路生成的第一信号和第二信号。
第四方面，提供一种雷达装置，雷达装置包括接收器和处理器，接收器包括至少一根接收天线，其中：
接收器，用于接收如第二方面任一种可能的设计中的回波信号；
处理器，用于根据回波信号执行如二方面任一种可能的设计中的方法。
第五方面，提供一种雷达装置，包括：存储器与处理器，存储器用于存储指令，处理器用于执行存储器存储的指令，并且对存储器中存储的指令的执行使得，处理器用于生成如第一方面任一种可能的设计中的第一信号和第二信号。
第六方面，提供一种雷达装置，包括：存储器与处理器，存储器用于存储指令，处理器用于执行存储器存储的指令，并且对存储器中存储的指令的执行使得，处理器用于执行第二方面任一种可能的设计中的方法。
第七方面，提供一种可读存储介质，包括计算机程序或指令，当执行计算机程序或指令时，如第一方面或第二方面任一种可能的设计中的方法被执行。
第八方面，提供一种计算机程序产品，包括计算机可读指令，当雷达装置读取并执行计算机可读指令，使得雷达装置执行如第一方面或第二方面任一种可能的设计中的方法。
附图说明
图1(a)至图1(b)为适用于本申请实施例的一种雷达装置结构架构示意图；
图2为本申请实施例提供的一种车辆的结构示意图；
图3为本申请实施例提供的一种雷达信号发射流程示意图；
图4为本申请实施例提供的一种雷达信号示意图；
图5为本申请实施例提供的另一种雷达信号示意图；
图6为本申请实施例提供的另一种雷达信号示意图；
图7为本申请实施例提供的一种雷达信号接收流程示意图；
图8为本申请实施例提供的另一种雷达信号接收流程示意图；
图9为本申请实施例提供的另一种雷达信号接收流程示意图；
图10(a)至图10(c)为本申请实施例提供的一种多普勒谱线示意图；
图11为本申请实施例提供的一种多普勒谱线示意图；
图12为本申请实施例提供的一种多普勒谱线示意图；
图13为本申请实施例提供的一种多普勒谱线示意图；
图14为本申请实施例提供的一种多普勒谱线示意图；
图15为本申请实施例提供的一种多普勒谱线示意图；
图16为本申请实施例提供的一种多普勒谱线示意图；
图17为本申请实施例提供的一种雷达装置结构示意图；
图18为本申请实施例提供的一种雷达装置结构示意图。
具体实施方式
下面将结合附图对本申请实施例作进一步地详细描述。
如图1(a)所示，为本申请实施例提供的一种雷达装置示意图。图1(a)中的雷达装置可以为MIMO雷达，可以包括天线阵列101、微波集成电路(monolithic microwave integrated circuit，MMIC)102和处理器103。天线阵列101可以包括多根发射天线和多根接收天线。
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中发射天线阵列中一个或多根发射天线将雷达信号发出。需要说明的是，本申请实施例中，雷达装置的发射天线发送的信号的波形为FMCW，其频率通过使信号频率随时间上升和下降来调制，这种信号通常包括一个或多个“啁啾(chirp)信号”。一个时隙可以表示为单根发射天线发射一个chirp信号的占用时间，T SIMO＝T ramp+T other，其中T ramp表示实际用于测量的扫频信号的时间，T other表示由于实际器件如模拟数字转换器(Analogy to Digital Converter，ADC)，锁相环(Phase Locked Loop，PLL)引入的额外的时间开销。可以理解的是，由于本申请中，采用了时分和相位调制技术，因此，雷达装置中每一根发射天线的射频链路中，还包括开关和移相器。
举例来说，如图1(b)所示，为本申请实施例提供的一种微波集成电路示意图。图1(b)中，微波集成电路可以包括一条或多条射频接收通道以及射频发射通道。射频发射通道中可以包括波形发生器、移相器、开关以及功率放大器(power amplifier，PA)等模块。射频接收通道中可以包括低噪声放大器(low noise amplifier，LNA)，下混频器(mixer)，滤波器以及模数转换器(analog to digital converter，ADC)等模块。
图1(b)只是示例，微波集成电路还可能存在其他形式，本申请实施例对此并不限定。
在发射雷达信号之前，处理器将配置好的雷达信号的波形通过射频发射通道中的波形发生器实现。本申请实施例中多发射天线的正交发射波形可以由处理器预先配置，不限于处理器的名称，仅表示实现预先配置波形的功能。由于本申请实施例中，雷达信号可能在不同的发射天线中时分方式发送，为此可以通过开关选通需要发送雷达信号的发射天线。并且，雷达信号可能在不同的发射天线中码分发送，通过与该发射天线连接的移相器调制相应的相位。其中开关和移相器串行连接天线和波形发射器，但其中开关和移相器的顺序可以交换。
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中接收天线阵列中部分或全部接收天线上接收到的回波信号进行混频和采样等处理，并将采样后的回波信号传输至处理器103。
其中，处理器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、角度等信息。具体地，该处理器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(a)所示的雷达系统还可以包括电子控制单元(electronic control unit，ECU)104，用于根据处理器103处理后得到的目标距离、速度、角度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包括发射天线与微波集成电路102中的发射通道，接收器包括接收天线与微波集成电路102中的接收通道。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，即封装天线(antenna in package，AIP)。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器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，处理器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(a)所示的雷达装置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(a)所示的雷达装置实现。
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。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。
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214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，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214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214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214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。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214)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。
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。
结合前面的描述，本申请提供一种雷达信号发射和接收方法，该方法应用于雷达装置，雷达装置包括N根发射天线，N>m，m为大于或等于2的整数。应理解的是，该雷达装置的具体结构可以如图1(a)所示，也可以不限于图1(a)的具体结构，本申请对此不作限定。
参见图3，在发送侧，该方法包括：
步骤301：在S个时隙中通过N根发射天线中的1根发射天线发送第一信号。
本申请实施例中，第一信号的相位在S个时隙中不变。举例来说，第一信号的相位在S个时隙中第一时隙的相位为
Figure PCTCN2020093630-appb-000001
那么在其他时隙中相位均为
Figure PCTCN2020093630-appb-000002
示例性的，第一信号在S个时隙中的信号波形为FMCW。
步骤302：在S个时隙中通过N根发射天线中的m根发射天线采用时分方式或码分方式中的至少一种方式发送第二信号。
其中，第二信号在S个时隙中的信号波形也是FMCW，第一信号和第二信号采用不同的相位调制编码。
码分方式，表示码分多址(Code Division Multiple，CDM)，或多普勒复用制式(Doppler Division Multiplex，DDM)或多普勒分多址(Doppler-Division Multiple Access，DDMA)中通过调制信号的相位形成编码的方式，即相位调制编码。
第二信号通过m根发射天线发送，相当于是m根发射天线发送的信号的叠加。第二信号中通过m根发射天线中的每根发射天线发送的信号采用2πk y/P的步长进行相位调制，P为大于1的整数，k y为大于0且小于P的整数，其中k y表示m根发射天线中的第y个发射天线采用的相位调制步长，y＝1,…,m，P为大于1的整数。本申请实施例中，第二信号的调制相位可以包括P个相位，P个相位为[0，2π)中均匀的P个相位，对应的相位集合可以为[0，2π/P，4π/P，6π/P，…，(P-1)*2π/P]。由于P至少等于2，例如，对于P＝2时，那么P个相位分别为0和π，如图1(b)中所示；可以理解，对于P＝4时，那么P个相位分别为0、π/2、π和3π/2，即图1(b)中移相器能在整个FMCW扫频斜率范围能提供高精度的0、π/2、π和3π/2一共4个相位。值得注意的是对于复数信号，相位调制等效于信号乘以exp(jφ)，有2π周期旋转后等值的特性。因此，实际系统只用P个相位，可以实现2π整数倍的其他相位调制。即可以用2π/P的相位调制，代替2π/P+u*2π的相位，u为整数。
值得注意的是，由于第二信号和第一信号都占用S个时隙中发射，因此，步骤301和步骤302并没有先后顺序。仅表示第一信号和第二信号采用不同码分，即不同多普勒偏移2πk y/P的步长进行相位调制，P为大于1的整数，k y为大于或等于0且小于P的整数。当k y等于0时，可以理解为该发射天线在多个时隙中，即相邻时隙间占用的信号变化为零。
由于第一信号中仅包括一根发射天线的信号，占用S个连续时隙，因此，第一信号可以是一种SIMO信号，其优点是测速范围较大。而第二信号中包括m根发射天线的信号，可以理解为是一种TDM MIMO信号，其优点是测量的角度分辨率较大。由于目标在测量的时候会运动，而SIMO信号和TDM MIMO信号是依靠匹配相同距离单元上的速度索引获得目标不混叠速度的。如果第一信号和第二信号不是同时发射的，在前后发射的SIMO信号和MIMO信号有可能会造成目标匹配不到相同的距离单元，即出现对目标的观测时间 不同，导致无法准确测量目标的速度。而本申请中第一信号和第二信号是同时发射的，因此，改善了现有技术中时分发射SIMO信号和TDM MIMO信号时，对于高速运动目标的观测时间不同，导致无法准确测量目标的速度的问题。
当P＝2时，即二相位调制，(也有文献称为BPSK(Binary Phase Shift Keying)-------二进制相移键控，本申请实施例不做特别限制)，第一信号和第二信号分别采用2πk y/P，k y＝0，1中任意步长进行相位调制。可以理解k y＝0时，步长相邻时隙中的相位步长为0，即S个时隙中相位不变的情况，可以理解相位调制编码为[1,1]，其中这个序列中的元素表示信号的调制相位，1表示调制相位为0，-1表示调制相位为π。当k y＝1时，每根发射天线发送的信号采用π的步长进行相位调制，即第二信号中每根发射天线的相位调制编码都相同,即为[1,-1]。因此，为了区分第二个信号中的m根发射天线的正交波形，第二信号中，m根发射天线进一步采用时分方式发送信号。由于TDM MIMO发射不受相位控制限制，因此，可以容易的通过第二信号中多根发射天线扩展雷达系统的发射天线数目，即m可以为大于或等于2任意整数。通过这种方法，解决现有二相位DDM波形，无法实现更多发射天线的正交发射的问题。并且第一信号在S个时隙中连续发射，保证了雷达系统的最大测速范围。避免采用TDM MIMO发射引入雷达系统测速范围下降的问题。
实际上在P＝2时，第一信号也可以采用π的步长进行相位调制。第二信号中多根发射天线的信号都采用0步长，即以相位不变的方式发射。但由于第一信号的测速范围较大，因此，如果第一信号采用0步长进行相位调制，则第一信号在接收端的回波信号可以获得较大测速范围内，而且没有非零相位调制步长引起的额外的多普勒偏移，进一步简化接收处理流程。因此，本申请实施例以第一信号采用0步长进行相位调制为例，描述后续实施例。
示例性的，m根发射天线中每根发射天线以P*M个时隙为周期进行重复发送。因为第二信号中采用2πk y/P的步长进行相位调制的多根发射天线，需要P个时隙完成均匀多普勒调制。而采用时分的多根发射天线需要M大于或等于2的时隙完成时分发射。因此，这里表达为每根发射天线以P*M个时隙为周期进行重复发送。例如，P＝2，N＝3，m＝N-1＝2时，要以4个时隙为周期进行发送至少1次。
每根发射天线以P*M个时隙为周期进行重复发送时，一根发射天线在每个周期按照一个发射样式进行发送，发射样式表示信号被调制的相位和幅值关系，采用时分方式发射天线的信号，占用间隔为M个时隙的不冲突的P个时隙，M为m根发射天线中一根发射天线占用的时隙中的相邻时隙之间相隔的时隙数量，M为大于或等于m/(P-1)的整数。
为了提高速度分辨率，进一步的，(Nd+1)*P*M>S>＝Nd*P*M，其中Nd表示m根发射天线以P*M个时隙为周期，发射的周期次数，Nd为大于或等于1的整数。M的具体取值，可以根据实际情况确定，满足M为大于或等于m/(P-1)的整数。这里说明S可以不等于Nd*P*M整数倍，在接收端可以做补零操作，这里并不做限制。
结合前面的描述，由于P为大于1的整数，Nd为大于或等于1的整数，M为大于1的整数，因此S为大于或等于4的整数。S的具体取值，可以根据实际情况确定，在此不做限制。
本申请实施例中，m根发射天线中的每根发射天线发送的信号可以通过时分方式或者码分方式区分，即不同发射天线发送的信号占用不同时隙，或者m根发射天线中占用相同时隙的发射天线发送的信号采用2πk y/P的步长进行相位调制时，k y取值不同。这样即使P 的数目不能取到很大，例如P小于等于4时，N根发射天线的信号仍然可以实现正交发射。
举例来说，m根发射天线中占用相同时隙的发射天线发送的信号采用2πk y/P的步长进行相位调制时，k y取值不同。例如，发射天线1和发射天线2在占用相同时隙中发送信号，P＝4时，发射天线1对应的k y的取值为1，即发射天线1发送的信号的相位依次以0、π/2、π和3π/2循环；发射天线2对应的k y的取值为3，即发射天线2发送的信号的相位依次以0、3π/2、3π＝2π+π和9π/2＝4π+π/2循环。其中，为了描述方便，可以将一个周期中，一根发射天线发送的信号的相位的组合，称为该发射天线的发射样式，那么根据欧拉公式
Figure PCTCN2020093630-appb-000003
即发射天线1的在4个占用时隙中信号的相位依次以0、π/2、π和3π/2循环，表示为复数的形式，发射天线1，在P*M个时隙中占用间隔M的P个时隙中相位可以表示为[1，j，-1，-j]；同理发射天线2，在P*M个时隙中占用间隔M的P个时隙中相位可以表示为[1，-j，-1，j]。但可以理解，这里的发射样式，仅能表示相位调制，无法表示时分的天线。因此，本申请实施例中，引入x表示静默，在该时隙内不发送信号，也可以用0表示，可以理解在这个时隙内信号的幅值被置为零，实际系统可以通过开关设置为断开状态实现。可以计算得到，P＝4，M＝2时，m小于等于M*(P-1)，取m的最大值m＝6，N＝m+1，则可以扩展到7根发射天线。具体发射样式，可以参考具体实施例。
本申请实施例中，为了描述方便，将发送第一信号的发射天线记为Tx0，将发送第二信号的发射天线记为Tx1至Txm。
进一步的，本申请实施例中，发送第二信号的m根发射天线与发送第一信号的1根发射天线，可以为N根发射天线中不同的发射天线。那么发送第一信号的Tx0占用S个时隙中全部时隙。可以理解的P＝2，M>m/(P-1)＝m时，第二信号中m个信号，并没有占用S个时隙中的全部时隙，部分时隙中仅存在第一信号。例如，P＝2，N＝3，m＝N-1＝2时，M＝3，那么假设Tx1占用时隙1和时隙4，Tx2占用时隙2和时隙5，而时隙3和时隙6中就仅存在第一信号，即Tx0发送的信号。
或者，发送第一信号的1根发射天线可以为m根发射天线中的一根发射天线，本申请实施例并不限定。那么对应冲突的时候，发射天线用第二信号的相位编码发射，第一信号中对应的时隙类似可以有少量时隙中信号空缺。例如，P＝2，N＝3，m＝N＝3时，M＝3，那么假设Tx1占用时隙1和时隙4，Tx2占用时隙2和时隙5，而时隙3和时隙6中Tx0发送的信号如果采用第二信号的规则，即步长为π发射Tx0。那么采用了第二信号的规则发射的第一信号，在S个时隙中每个3个有一个空缺。当然，当M比较小的时候，可以看到在S个时隙中，按照第一信号特征发射的天线空缺的比例接近为1/M，造成SIMO的信号相当于被降采样。因此，这种发射方式在M比较大使用比较合适，比如M大于3时。
举例来说，m个发射天线中占用相同时隙的发射天线发送的信号采用2πk y/P的步长进行相位调制时，k y取值不同，例如k y＝1,2，…,P-1。例如，P＝3时，第二信号中的m个天线的k y取值为1,2，发射天线1对应的k y的取值为1，即发射天线1发送的信号的相位依次以0、2π/3、4π/3循环；发射天线2对应的k y的取值为2，即发射天线2发送的信号的相位依次以0、4π/3、8π/3＝2π+2π/3循环。其中，为了描述方便，可以将一个周期中，一个发射天线发送的信号的相位的组合，称为该发射天线的发射样式，那么根据欧拉公式exp(jψ)，即发射天线1的在3个占用时隙中信号的相位依次以0、2π/3、4π/3循环，表示为复数的形式，发射天线1，在P*M个时隙中占用间隔M的P个时隙中相位可以表示为[1，exp(j2π/3)，exp(j4π/3)]；同理发射天线2，在P*M个时隙中占用间隔M的 P个时隙中相位可以表示为[1，exp(j4π/3)，exp(j2π/3)]。但可以理解，这里的发射样式，仅能表示相位调制，无法表示时分的天线。因此，本申请实施例中，引入x表示静默，在该时隙内不发送信号，也可以用0表示，可以理解在这个时隙内信号的幅值被置为零，实际系统可以通过开关设置为断开状态实现。可以计算得到，P＝3,M＝2时，m小于等于M*(P-1)，取m的最大值m＝4，N＝m+1＝5，则可以扩展到5个发射天线。如果M取更大值，可以很容易扩展到更多的N取值。具体发射样式，不再赘述。
下面通过具体的N，m，M，P取值实施例描述不同的第一信号和第二信号。
实施例一：
如图4所示，为本申请实施例提供的一种信号示意图。图4中，以N＝3，即有3根发射天线用于雷达信号发射，P＝2，即移相器至少能提供稳定的0、π相位调制，m＝2，第二信号中包括两根发射天线为例进行说明。根据前面的描述，M为大于或等于m/(P-1)的整数。那么可以计算得到M大于或等于2，取M的最小值，M＝2为例进行描述。在图4中，第一信号通过发射天线Tx0发送，在S个时隙中，第一信号包括S个chirp信号，每个chirp信号间的相位不变。
第二信号包括多个chirp信号，第二信号通过发射天线Tx1和发射天线Tx2时分发送，Tx1和Tx2发送的信号的周期为4个时隙，Tx1在每个周期的发射样式可以表示信号被调制的相位和幅值关系为[1,x,-1,x]，Tx2在每个周期的发射样式的信号可以表示信号被调制的相位和幅值关系为[x,1,x,-1]。其中，x表示静默，在该时隙内不发送信号，也可以用0表示，即Tx1在每个周期的发射样式可以写成[1,0,-1,0]，Tx2在每个周期的发射样式可以写成[0,1,0,-1]，可以理解在这个时隙内信号的幅值被置为零，实际系统可以通过开关设置为断开状态实现；1表示该时隙内的chirp信号的相位被调制了0弧度；-1表示该时隙内的chirp信号的相位为被调制了π弧度，实际系统中可以用开关设置为闭合状态和移相器对应相位选择来实现。从图4可以看出，Tx1发送的信号占用的时隙和Tx2发送的信号占用的时隙不同；Tx1发送的信号占用的时隙中，相邻时隙之间相隔2个时隙；Tx2发送的信号占用的时隙中，相邻时隙之间相隔2个时隙。
需要说明的是，图4中给出的chirp信号是上升的线性连续调频波，chirp信号也可以是下降的线性连续调频波，本申请实施例不做限定。
由于第一信号和第二信号分别采用了不同相位调制编码，并且只用到了0和π相位，因此，仅需要具有较稳定的二相位调制器就可以实现第一信号和第二信号发射，降低了对芯片的要求。为了提高速度分辨率，进一步的，可以增加S个时隙占用的时间长度，并满足S>＝Nd*P*M，其中Nd表示m根发射天线的发射样式的重复次数，Nd大于或等于1。发射样式表示采用时分方式的发射天线的信号占用间隔为M个时隙的不冲突的P个时隙，M为m根发射天线中一根发射天线占用的时隙中的相邻时隙之间相隔的时隙数量，M为大于或等于m/(P-1)的整数。M的具体取值，可以根据实际情况确定，满足M为大于或等于m/(P-1)的整数。
在这个实施例中，取M＝m/(P-1)，可以理解这样第二个信号对应的最大测速范围取到最大值。而M也可以取大于m/(P-1)的整数，比如N＝3，P＝2，M＝3，这样的方法虽然降低了第二信号的最大测速范围，但是部分时隙中，第一信号和第二信号使用的相位步长数目可以小于P，那么在接收端可以利用空缺的相位步长，确定第一信号的多普勒频率，进一步化简接收信号处理。具体的，第一信号是每个时隙都发送，发射第一信号的发射天线Tx0 的发射样式可以写成6个时隙表示为[1,1,1,1,1,1]；发射第二信号的多根发射天线的发射样式分别如下：Tx1的发射样式可以写成6个时隙表示为[1,x,x,-1,x x]，Tx2的发射样式在6个时隙内的表示为[x,1,x,x,-1,x]，那么在第3时隙、第6时隙内中仅存在第一信号中的发射天线信号，而第二根发射天线的信号在第3时隙、第6时隙中通过开关选通控制，并没有任何天线被选通。那么抽取第3时隙、第6时隙中的回波信号，观察到的多普勒频率即为第一信号中的发射天线信号回波信号。和第1时隙、第4时隙中，第2时隙、第5时隙中的多普勒频率，就包括第一信号中的发射天线信号回波信号和第二信号。通过比较不同时隙中的子RD图，可以很容易的找到第一信号中的发射天线对应的多普勒频率。
在这个实施例中，根据对分辨率精度的要求，可以进一步约束Nd的大小。这里示例性给出Nd＝32时，可以根据S>＝Nd*P*M得到S的最小取值32*2*2＝128，即上述每根发射天线在4个时隙的发射样式被重复发射了32次。可以理解，Nd还可以取其他的任意整数值，在此不再赘述。
实际上，根据上面的描述，当P＝2，N＝12，M＝11时的发射样式可以如表1所示。
表1
Figure PCTCN2020093630-appb-000004
表1中第一行中的每一格代表1个时隙，第一列中的每一格代表1根发射天线。表1中的发射天线的编号只是逻辑编号，编号相邻的发射天线不代表实际的空间相邻关系。第一信号的发射天线记做Tx0，采用0相位调制信号。第二信号的发射天线记做Tx1-Tx11，由于P＝2，k y＝1，m＝N-1＝11，第二信号中11根发射天线发射的信号，都采用2πk y/P＝π步长对信号进行调制。其中发送第二信号的发射天线Tx1-Tx11采用时分发射天线，占用间隔为M＝m/(P-1)＝11个时隙的不冲突的P＝2个时隙。
实施例二：
实施例二中，除了在S个时隙中同时发送第一信号和第二信号之外，进一步在S个时隙之后的S0个时隙中，还可以通过m根发射天线采用时分方式发送第三信号，S0为大于1的整数。
第三信号在S0个时隙中的发射样式和第二信号在S个时隙中的发射样式相同，S＝Nd*P*M，M为大于或等于m/(P-1)的整数。
S0个时隙中不存在第一信号，由于Tx0发送的第一信号只存在于S时隙中，因此可以 通过比较在S0个时隙内的接收回波信号中的多普勒频率和S个时隙中接收回波信号中的多普勒频率确定目标的多普勒频率，确定S个时隙中Tx0对应的多普勒索引位置，进一步简化接收侧获得目标速度的流程。
举例来说，结合图4，如图5所示，为本申请实施例提供的一种信号示意图。图5中，以m＝2，P＝2，M＝2为例进行描述。在图5中，在前面的S个时隙中发送的第一信号和第二信号可以参考图4所示。在S个时隙之后的S0个时隙中，通过Tx1和Tx2发送第三信号。第三信号的发射样式和第二信号的发射样式相同，即Tx1和Tx2发送的信号的周期为4个时隙，Tx1在每个周期的发射样式的信号可以表示信号被调制的相位和幅值关系为[1,x,-1,x]，Tx2在每个周期的发射样式的信号可以表示信号被调制的相位和幅值关系为[x,1,x,-1]。从图5可以看出，Tx1在S0个时隙中发送的信号与在S个时隙中发送的信号相同，Tx2在S0个时隙中发送的信号与在S个时隙中发送的信号样式相同。其中，x表示静默，在该时隙内不发送信号，也可以用0表示，可以理解在这个时隙内信号的幅值被置为零，实际系统可以通过开关设置为断开状态实现；1表示该时隙内的chirp信号的相位被调制了0弧度；-1表示该时隙内的chirp信号的相位为被调制了π弧度，实际系统中可以用开关设置为闭合状态和移相器对应相位选择来实现。从图5可以看出，Tx1发送的信号占用的时隙和Tx2发送的信号占用的时隙不同；Tx1发送的信号占用的时隙中，相邻时隙之间相隔2个时隙；Tx2发送的信号占用的时隙中，相邻时隙之间相隔2个时隙。
另外当S＝128，S0＝128时，可以理解为第二信号中2根发射天线使用4个时隙中预定的发射样式重复发射32*2＝64次。而第一信号中1根发射天线使用4个时隙中预定的发射样式重复发射32次。由于测量目标的速度的速度分辨率，与S和S0的大小成反比，可以理解的S和S0可以取其他的大于0的整数值，取值越大，速度分辨率越高。
实施例三：
前面的实施例中，以P＝2为例进行描述。第二信号包括的相位数量P也可以为其它值，例如当P＝4时，如图6所示，为本申请实施例提供的一种信号示意图。图6中，以m＝6，P＝4，M＝2为例进行描述。在图6中，第一信号通过发射天线Tx0发送，第一信号包括S个chirp信号，每个chirp信号的相位保持不变。
第二信号通过发射天线Tx1至发射天线Tx6发送，每根发射天线发送的信号的周期为8个时隙。可以将6根发射天线分为2组，一组包括Tx1、Tx2和Tx3，另一组包括Tx4、Tx5和Tx6。
Tx1、Tx2和Tx3可以占用相同的时隙，但分别采用不同相位调制编码发送信号。具体的，Tx1在每个周期的发射样式的信号可以表示信号被调制的相位和幅值关系为[1,x,j,x,-1,x,-j,x]，即步长为π/2，Tx2在每个周期的发射样式的信号可以表示信号被调制的相位和幅值关系为[1,x,-1,x,1,x,-1,x]，即调制步长为π，Tx3在每个周期的发射样式的信号可以表示信号被调制的相位和幅值关系为[1,x,-j,x,-1,x,j,x]，即调制步长为3π/2。其中，x表示静默，在该时隙内不发送信号；1表示该时隙内的chirp信号的相位被调制了0弧度；j表示该时隙内的chirp信号的相位被调制了π/2弧度；-1表示该时隙内的chirp信号的相位被调制了π弧度；-j表示该时隙内的chirp信号的相位被调制了3π/2弧度。
第一组中Tx4、Tx5和Tx6和第二组Tx1、Tx2和Tx3占用不同的时隙发送信号，即时分正交。类似的，Tx4在每个周期的发射样式的信号可以表示信号被调制的相位和幅值关系为[x,1,x,j,x,-1,x,-j]，即调制步长为π/2，Tx5在每个周期的发射样式的信号可以表示 信号被调制的相位和幅值关系为[x,1,x,-1,x,1,x,-1]，即调制步长为π，Tx6在每个周期的发射样式的信号可以表示信号被调制的相位和幅值关系为[x,1,x,-j,x,-1,x,j]，即调制步长为3π/2。
需要说明的是，Tx4发送的信号的发射样式可以是Tx1发送的信号的发射样式的循环移位序列。循环移位序列，可以是指对一个基序列按照顺时针或逆时针移位方式获得的新序列。如基序列为[1,x,j,x,-1,x,-j,x]的循移位序列，按照逆时针循环移位1次，可以获得的序列为[x,1,x,j,x,-1,x,-j]；按照顺时针循环移位2次，可以获得的序列为[j,x,-1,x,-j,x,1,x]等。相应的，Tx5发送的信号可以是Tx2发送的信号的循环移位序列，Tx6发送的信号可以是Tx3发送的信号的循环移位序列样式。其中占用相同时隙的一组天线中每根发射天线选用的具体相位步长只要不同即可，本申请并不限定实施例中给出的发射天线顺序对应的具体相位步长。
进一步，当P＝4，N＝16时的发射样式可以用表2表示。
表2
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Tx0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Tx1 1         j         -1         j        
Tx2 1         -1         1         -1        
Tx3 1         -j         -1         j        
Tx4   1         j         -1         j      
Tx5   1         -1         1         -1      
Tx6   1         -j         -1         j      
Tx7     1         j         -1         j    
Tx8     1         -1         1         -1    
Tx9     1         -j         -1         j    
Tx10       1         j         -1         j  
Tx11       1         -1         1         -1  
Tx 12       1         -j         -1         j  
Tx 13         1         j         -1         j
Tx 14         1         -1         1         -1
Tx 15         1         -j         -1         j
表2中第一行中的每一格代表1个时隙，第一列中的每一格代表1根发射天线。表2中的发射天线的编号只是逻辑编号，编号相邻的发射天线不代表实际的空间相邻关系。第一信号的发射天线记做Tx0，采用0相位调制信号。第二信号的发射天线记做Tx1至Tx15。如果P＝4，实现N＝16发射天线的发射，M至少为(N-1)/(P-1)＝5，那么发射样式表示P*M的4*5＝20个时隙，第一信号的发射天线记做Tx0，采用0相位调制信号，[1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1]表示20时隙的调制信号；第二信号通过Tx1至Tx15分别采用时分或码分发送，即码分的天线采用π/2，π,3π/2为步长调制，而时分的天线分别占用间隔为M＝(N-1)/(P-1)＝5个时隙的不冲突的P＝4个时隙。在Tx1和Tx2，Tx3可以分别采用不同相位调制编码发送，发送的20时隙的调制信号分别表示为[1,x,x,x,x,j, x,x,x,x,-1,x,x,x,x,-j,x,x,x,x]，[1,x,x,x,x,-1,x,x,x,x,1,x,x,x,x,-1,x,x,x,x],[1,x,x,x,x,-j,x,x,x,x,-1,x,x,x,x,j,x,x,x,x]。Tx4和Tx5，Tx6可以和Tx1-Tx3采用不同时隙，例如相位编码为Tx1-Tx3逆时针循环移动1个时隙，发送的20时隙的调制信号分别表示为[x,1,x,x,x,x,j,x,x,x,x,-1,x,x,x,x,-j,x,x,x]，[x,1,x,x,x,x,-1,x,x,x,x,1,x,x,x,x,-1,x,x,x],[x,1,x,x,x,x,-j,x,x,x,x,-1,x,x,x,x,j,x,x,x]。类似的Tx7～Tx9相位编码为Tx1-Tx3逆时针循环移动2个时隙，Tx10～Tx12相位编码为Tx1-Tx3逆时针循环移动3个时隙，Tx13～Tx15相位编码为Tx1-Tx3逆时针循环移动4个时隙。
需要说明的是，P等于其它值时，第一信号以及第二信号的具体结构可以参考前面的描述，在此不再赘述。
实施例四：
前面的描述中，发送第二信号的m根发射天线，在S个时隙中采用相同的配置发送信号。m根发射天线还可以在S个时隙中，第二信号中m根发射天线分成不同组，每组选用不同M i或m i，i取1,2至少两个配置。
举例来说，在S个时隙中的前S1个时隙，m根发射天线中的N1根发射天线，可以以P*M1个时隙为周期，在一个周期的P*M1个时隙中选择不冲突的相隔M1的P个时隙分别发送第二信号；在S个时隙中的后S2个时隙，m根发射天线中除N1根发射天线之外的N2根发射天线以P*M2个时隙为周期，在一个周期的P*M2个时隙中选择不冲突的相隔M2的P个时隙分别发送第二信号；其中，m＝N1+N2，N1>＝2，N2>＝1；S＝S1+S2，M1≠M2，M1>＝N1/(P-1)，M2>＝N2/(P-1)。
例如，以N＝5，m＝N-1＝4，P＝2，N1＝2，N2＝2，M1＝2，M2＝3，为例进行描述。第一信号通过发射天线Tx0发送，第一信号包括S个chirp信号，每个chirp信号的相位保持不变。
第二信号通过发射天线Tx1至发射天线Tx2发送，Tx1在每个周期的发射样式可以表示信号被调制的相位和幅值关系为[1,x,-1,x]，Tx2在每个周期的发射样式的信号可以表示信号被调制的相位和幅值关系为[x,1,x,-1]。Tx4在每个周期的发射样式可以表示信号被调制的相位和幅值关系为[1,x,x,-1,x,x]，Tx4在每个周期的发射样式的信号可以表示信号被调制的相位和幅值关系为[x,1,x,x,-1,x]Tx1和Tx2发送的信号的周期为4个时隙，被重复发射Nd1次，Tx3和Tx4发送的信号的周期为6个时隙，被重复发射Nd2次，其中Nd1与Nd2均大于或等于2。即可以理解为S＝Nd1*4，S2＝Nd2*6。
和其他实施例类似，Nd1、Nd2可以取更大的整数，进一步提高速度分辨率，例如Nd1＝Nd2＝32。这样的多配置可以避免速度相差最大测速范围一半的两个目标，其中目标1的Tx0信号的回波信号的多普勒索引正好落和目标2被调制到π相位的Tx1和Tx2的信号的回波信号的多普勒索引相同。由于配置1和配置2的M1和M2不同，因此，在配置1中的最大测速范围和配置2的最大测速范围不同，即使在配置1中目标1和目标2在Tx0信号的回波很难区分为两个目标，在配置2中，可以很轻松的被识别。因此，避免由于Tx0信号的回波信号包含多普勒频率相差Vmax*k/P多个目标的混叠。由于不同配置的Vmax＝λ/(4*T)，对于不同M配置，导致发射重复周期T＝M*T SIMO不同。这里配置1的发射重复周期T1＝2*T SIMO，而配置2的发射重复周期T1＝3*T SIMO，在配置1中多普勒谱线冲突的两个目标，在配置2中就可以分开。
以上只是以示例，在S个时隙中还可以采用其他不同的配置，或者扩大到P＝4的情况， 在此不再逐一举例说明。
与图3所示的信号发送方法相对应地，本申请实施例还提供一种方法，用于对第一信号和第二信号经一个或多个目标反射后形成的回波信号进行处理，从而获取一个或多个目标的速度，进而获取一个或多个目标的角度信息(例如水平方位角和垂直方位角)。
该方法可以应用于雷达装置，尤其是MIMO雷达。雷达装置包括N根发射天线以及至少一根接收天线，参见图7，该方法包括如下步骤：
步骤701：接收第一信号和第二信号经至少一个目标反射后形成的回波信号。
其中，第一信号和第二信号的具体内容可以参考图3所示的流程所示。
即接收第一信号和第二信号经过至少一个目标反射后形成的回波信号；其中，第一信号在S个时隙中通过N根发射天线中的1根发射天线发送，第一信号的相位在S个时隙中不变；第二信号在S个时隙中通过N根发射天线中的m根发射天线采用时分和码分方式中的至少一种方式发送；第二信号中通过m根发射天线中的每根发射天线发送的信号采用2πk y/P的步长进行相位调制，P为大于1的整数，k y为大于0且小于P的整数，其中k y表示m根发射天线中的第y个发射天线采用的相位调制步长，y＝1,…,m；S为大于或等于4的整数；
步骤702：获得每根接收天线的M个子距离-多普勒图(range doppler map，RD Map)。
这里的每根接收天线是指雷达装置包括的所有接收天线中的每根接收天线。其中每根接收天线的M个子RD图中的第i个子RD图，为接收天线在S个时隙的回波信号中起始时隙分别为i，每隔M个时隙的信号2D-FFT的结果，i取1,2,…,M的任意整数。
步骤703：根据每根接收天线的M个子RD图累积后的子RD图检测第一目标，并获得第一目标的距离信息。
其中，第一目标为至少一个目标中的一个或多个目标。
通过图7所示的流程可以获得第一目标的距离信息，本申请实施例还可以获得第一目标的角度信息以及速度信息，具体可以如图8所示。
步骤801：根据接收到的回波信号的差频信号，分别在每个时隙内执行一维快速傅里叶变换(Fast Fourier Transformation，FFT)(1D-FFT)，即距离维度的快速傅里叶变换。
假设Nrx根接收天线在每个时隙内，获得了多个采样信号，距离维度FFT的大小为Nrange，对每个时隙内一根接收天线多个采样信号进行FFT运算，获得的复数矩阵维度为Nrange*S*Nrx。
步骤802：在1D-FFT的结果基础上，逐一计算每个距离单元内抽取起始时隙分别为1到M的每隔M个时隙的信号做二维FFT(2D-FFT)，即多普勒傅里叶变换，在Nrx根接收天线上分别获得M个子RD图的复数值，从而获得每根接收天线的M个子RD图。
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距离单元(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)。
需要说明的是，在获得子RD图过程中，还可能存在对回波信号执行如下操作，如信号加窗(Windowing)、发送/接收通道校准(Tx/Rx Calibration)、补零(Zero-padding)等，本申请实施例不做限制，具体可以参考现有技术中的描述，在此不再赘述。
进一步的，获得每根接收天线的M个子RD图之后，可以在步骤703中，根据每根接收天线的M个子RD图检测第一目标，并获得该第一目标的距离信息，具体可以包括以下 步骤：
步骤803：累积多根接收天线上获得的M个子RD图，获得累积后的子RD图，并在累积后的子RD图上做检测，获得第一目标的距离索引Rind，即第一目标的距离信息。
具体的，获得第一目标的距离索引Rind和多普勒索引Vind，Vind是在[1，Nfft/P]范围内的检测到的目标的多普勒索引。根据Nrx根接收天线的M个子RD图的相干累积值或非相干累积值进行目标检测。其中相干累积值对于不同发射天线或接收天线的信号累积方式是同相位叠加的值，即选择预定角度波束方向上的最大值。而非相干累积值，不同发射天线或接收天线的信号累积方式采用幅值叠加的值。
可以在距离维做门限检测，这里不限制于采用恒虚警率(Constant False-Alarm Rate，CFAR)获得第一目标的距离索引Rind，也可以采用其他的检测方法，例如基于噪声门限的方法等。
步骤804a：在多普勒域上使用全部的S个时隙进行2D-FFT，获得总距离-多普勒图(range doppler map，RD Map)复数值。
具体的，在S个时隙1D-FFT的结果执行二维FFT(2D-FFT)，即多普勒维度的快速傅里叶变换，获得多个接收通道上信号总距离-多普勒图(range doppler map，RD Map)复数值。
累积多个接收通道上信号，获得一个总RD图中每个距离-多普勒单元的能量。可以理解，总RD图的维度为Nrange*(M*Nfft)，即距离维度和子RD图维度相同，多普勒维度为子RD图的M倍。
其中总RD图，是在步骤801的基础上在多普勒域上使用全部的S个时隙进行M*Nfft点的2D-FFT，不再进行M个间隔抽取。仅仅对Nrx根接收天线进行非相干叠加。
进一步的，为了简化计算，如图9所示，步骤804a可以替换为步骤804b：计算子RD图中检测到第一目标的距离索引Rind上的S个时隙内的2D-FFT多普勒谱。
为了确定第一信号经过目标反射的回波信号中的多普勒，可以配合发射波形进行多种不同的处理。
步骤805：确定第一目标在累积后的子RD图上第一信号的混叠的速度的至少一个多普勒索引Vind_sub，即获得Tx0在累积后的子RD图中多普勒索引Vind_sub。第一目标在累积后的子RD图上第一信号的多普勒索引Vind_sub为间隔Nfft/P的P个可能位置中的一个，其中Nfft是累积后的子RD图的2D-FFT的维度。
第一目标的距离单元Rind上抽取子RD图上多普勒值进行检测，即多普勒域做门限检测，获得第一目标在混叠Vmax/M范围内的速度，或者是第一信号的混叠的速度的至少一个多普勒索引Vind_sub。
但由于不同天线的信号被调制2πk y/P的相位，k y＝0,1，…P-1中相位调制。第一目标在累积后的子RD图上第一信号的混叠的速度的至少一个多普勒索引Vind_sub，并不能直接获得，而是位于相隔Nfft/P的P个谱线中，P个谱线包括Vind，Nfft/P+Vind，…，(P-1)Nfft/P+Vind，其中Nfft是累积后的子RD图的2D-FFT的维度，Vind是在[1，Nfft/P]范围内检测到的目标索引值。实际上由于多普勒谱具有2π循环特性，这里具体检测也可以检测累积后的子RD图的P个子区间任意一个子范围。比如选择[Nfft/P+1，2Nfft/P]区间内的Vind，那么对应P个谱线的位置为Vind-Nfft/P，Vind，…，(P-2)Nfft/P+Vind。
本申请实施例提出多种确定谱线Tx0谱线位置的方法，一种为步骤805中的方法，仅 利用M个子RD图的信息。另一种方法可以利用总RD图和子RD图，具体参考步骤806。
步骤805中的方法：仅利用M个子RD图。具体的，比较同一根接收天线的M个子RD图中每个子RD图中对应P根谱线的一对谱线的幅值差，幅值差较小的一对谱线对应的子RD图为Tx0所在的谱线位置，即确定子RD图中Tx0天线对应的多普勒索引。
由于Tx1～Txm在的谱线分别对应不同通道，因此幅值差异较大，而Tx0所在的谱线，由于是同一个通道，因此幅值差异小，因此可以根据幅值差异确定Tx0所在的谱线位置。其中Tx1～Txm分别为发送第二信号的m根发射天线。
步骤806：逐一抽取每个子RD图中的P根谱线的复数值，这P根谱线为子RD图中多普勒索引值为Vind，Nfft/P+Vind…(P-1)Nfft/P+Vind的P根谱线，将P根谱线的复数值和总RD图进行匹配，确定第一目标的速度，以及Tx0在累积后的子RD图上的对应速度。其中Vind是在[1，Nfft/P]范围内检测到的目标索引值。
需说明的是，通过该步骤，Tx0在累积后的子RD图上对应谱线和在总RD图上对应谱线都可以确定了。也就是说既确定第一目标的速度，又确定了Tx0在累积后的子RD图上的对应速度。
其中，由于速度本身带有方向，即远离雷达或靠近雷达，因此，在实际过程中Vind可以取正数或负数表示目标的是远离还是靠近。这里由发射波形参数确定的雷达装置的最大测速范围Vmax_total，通常为靠近和远离两个速度方向表示为正负的形式，即±Vmax_total＝λ/(4*T SIMO),λ为调制频率的波长，T SIMO为单个连续发射天线一个时隙长度，在本申请中记作发射天线Tx0发送信号的重复周期，发射天线Tx0为发送第一信号的发射天线。第一目标为至少一个目标中的任意一个目标。而第二信号是每隔M个时隙抽取的，±Vmax_sub＝λ/(4*M*T SIMO),λ为调制频率的波长，因此，在子RD图上确定的Tx0天线的多普勒索引值，还需要折算到Vmax范围内的速度索引值。第一目标的不混叠的速度的多普勒索引Vind_total＝Vind_sub+kk*Nfft-Nfft/2，其中kk表示由于子RD图是总RD图的每个M个降采样后的多普勒索引的混叠值，kk取值为0，…,M-1。注意，这里子RD中Vind_sub通过-Nfft/2进行了fftshift的操作，表示正负速度，而总RD中Vind_total可以通过fftshift操作获得正负的速度。由于不同应用有不同的正负速度定义，本申请实施例不做限制。
具体的，利用子RD图获得该距离单元上目标的个数，在总RD图上同一个距离单元上能量最大的谱线，即第一目标的不混叠的速度的多普勒索引Vind_total，匹配在子RD图上的混叠的速度的多普勒索引Vind_sub＝mod(Vind_total，Nfft)+Nfft/2的位置。根据个数依次迭代谱线和目标个数。
其中，由于在总的发射时间内，只有Tx0的信号一直在发射，因此，在总RD图中，一个目标的Tx0的谱线，比同一个目标的其他发射天线的谱线能量高要。
如图10(a)至图10(c)所示，示例出一个3发射天线时对应的多普勒频谱，图(a)至图10(c)中，在S个时隙中，第二信号的调制相位包括P个相位，发送第二信号的每根发射天线以P*M个时隙为周期进行重复发送。以P＝2，M＝2为例，一共发射了S＝256时隙，取Nfft＝S/2＝128，真实速度为0。图10(a)为所有时隙的多普勒频谱，即总RD图。图10(b)为时隙1和时隙3对应的多普勒频谱。图10(c)为时隙2和时隙4对应的多普勒频谱。图10(a)中，总RD图中，在对应某个目标距离单元Rind上，对应的多普勒谱线可能在不混叠的速度的多普勒索引Vind_total＝129左右(Nfft/P＝128/2＝64的标识)上各 有一个谱线，即在129-64＝65和129+65＝184都能检测到目标，即检测到目标的多普勒值较高。
图10(b)中，奇数时隙的多普勒频谱在1和65处各有一个谱线；图10(c)中，偶数时隙的多普勒谱在1和65处各有一个谱线。那么可以获得Tx0在子RD图上谱线的位置为混叠的速度的多普勒索引Vind_sub＝mod(129，Nfft＝128)+Nfft/2＝65，而不是索引为1的情况。
结合图10(a)至图10(c)可知，P＝2时谱线的间隔存在如下规律：在真实的多普勒索引Vind左右间隔Nfft/2处存在谱线，即Vind_total+Nfft/2或Vind_total-Nfft/2，其他谱线都在左右整数倍Nfft间隔上。另外可以理解，即使只有一个目标的多普勒速度，时分和码分发送的第二信号会形成多个多普勒谱线，如果按照现有技术中的方法，采用总RD图检测一个目标的对应的多普勒谱线有(P-1)*M+1个，直接在总RD图上检测Tx0上的一个目标的混叠的速度是非常困难的。而对于子RD图测速范围降低为总RD图的1/M时，始终存在相差Nfft/P关系的P个幅值较大的谱线，并且子RD图中的谱线个数不会随着第二信号的发射天线数目增加而增加，仅和相位调制中采用的相位调制步长k y的不同取值个数有关。因此，采用子RD图确定一个目标的混叠的速度的至少一个多普勒索引Vind_sub，只需匹配P个幅值较大的谱线，远远小于总RD图中需要匹配的多普勒谱线数目。
步骤807：根据Tx0在累积后的子RD图中的混叠的速度的多普勒索引Vind_sub，匹配总RD图获得第一目标不混叠的速度的多普勒索引Vind_total。
具体的，将通过累积后的子RD图中获得的Tx0的不混叠的速度的多普勒索引Vind_sub，以及公式Vind_total＝Vind_sub+kk*Nfft-Nfft/2，遍历不同的kk值，匹配到总RD图对应可能性上幅值最大的多普勒索引值，从而获得第一目标不混叠的速度的多普勒索引Vind_total，其中kk为混叠速度系数，kk取值为0,1，…,M-1。类似步骤806中的反过程。第一目标不混叠的速度就是第一目标的速度信息。
如图10(a)至图10(c)所示，实际上由于Tx0在子RD图上混叠的速度的多普勒索引Vind_sub＝65，不混叠的速度的多普勒索引Vind_total＝129，kk＝1。也可以知道，kk＝0时，Vind_total＝65-64＝1,而总RD图上，索引为Vind_total＝1的多普谱线上值远比Vind_total＝129的能量低，因此，也可以确认kk＝1，而不是等于0。注意，这里kk的取值使用的0，…,M-1的取值，也有表示正负区间的kk取值的方式，本申请实施例不做特别限制。
其中步骤805～807根据检测到的至少一个目标所在的多个距离单元上重复执行直到遍历完成。
进一步，还可以包括以下步骤：
步骤808：获取发射天线Tx0在不同接收天线上的2D-FFT变换后复信号。
可以理解的，即从Nrx根接收天线的M个子RD图的距离索引Rind和混叠的速度的多普勒索引Vind_sub对应的RD单元上提取该复数信号。
步骤809：补偿m根发射天线Tx1～Txm时分引起的多普勒相位偏差和码分引起的相位偏差，获得m根发射天线Tx1～Txm在不同接收天线上2D-FFT变换后的复信号。
需要说明的是，m＝0,1…M-1，对于第一个时隙，m取0，仅有时分引起的多普勒相位偏差或码分引起的相位偏差。m取其他值时，存在时分引起的多普勒相位偏差和码分引起的相位偏差。
其中由于选择了第m个时隙的发射天线，需要补偿的相位，可以用Vind_sub或Vind_total的函数表示。其中f(V ind_total)表示如果该天线对齐到Tx0的发射时刻和相位，在总RD图上2D-FFT的索引为(Rind,Vind_total)的RD单元的复数值，f(V ind_sub)表示在第m个时隙中发射，采用
Figure PCTCN2020093630-appb-000005
相位调制的天线，速度混叠系数为kk的信号，在第m个子RD图上索引为(Rind,Vind_sub)的RD单元的复数值。
Figure PCTCN2020093630-appb-000006
其中，由TDM时分时隙m中发射的天线，以及速度混叠系数引入的相位补偿量为
Figure PCTCN2020093630-appb-000007
而相位调制引起的变化
Figure PCTCN2020093630-appb-000008
其中k m为在m时隙中发射天线采用的发射波形采用的相位调制步长中k的取值。
该步骤中，通过计算每个目标不同时隙间的多普勒相移，从而可以通过相位补偿后获得分离的每根接收天线的复数信号。
具体可以存在两种方法：
方法9-1：根据N-1个子RD图中Tx0所在的谱线相位的相位差，确定不同时刻发射天线的多普勒补偿值。
由于Tx0所在的谱线，在不同子RD图上仅有由于时刻不同引入的相位，把这个相位作为补偿值给其他时分的天线补偿上去，则使得信号等效于同时发射。即等效于公式中的
Figure PCTCN2020093630-appb-000009
部分。
方法9-2：根据获得的第一目标的多普勒相位，把对应相位差补偿到不同时刻发射天线的多普勒补偿值。
其中由于选择了第m个时隙的发射天线，需要补偿的相位，可以用Vind_sub或Vind_total表示。
步骤810：根据补偿后的不同发射天线和接收天线形成的虚拟接收天线上的信号，获取第一目标的角度信息。
发射天线和接收天线合成得到的天线为虚拟接收天线(Virtual Receiver antenna)，又可描述为发射天线和接收天线合成得到虚拟接收阵列。根据虚拟接收天线的布阵，不限于采用FFT或数字波束赋形(digital beamforming，DBF)或多重信号分类(Multiple Signal Classification，MUSIC)或其他常用角度谱分析算法获得第一目标的角度信息，在此不再赘述。
需要说明的是，在步骤810中，还可以获得通过步骤807确定的距离信息和速度信息。
需要说明的是，步骤808～810会在步骤807输出的第一目标上重复执行。
需要说明的是，本申请还可以应用到发射天线数目到更大的情况。例如，如图11所示，为总RD图中一个距离单元中包含一个目标的多普勒谱线的示意图。图11最左边的总RD图上，4根发射天线至少需要6个时隙，总RD图上包括4个谱线；图11中间的总RD图上，5根发射天线至少需要8个时隙，总RD图上包括5个谱线；图11最右边的总RD图上，6根发射天线至少需要10个时隙，总RD图上包括6个谱线。其它情况不再赘述。从 这个图上可以看到，如果在总RD图上检测目标，由于非连续发射的天线速度的周期延拓，即使相位仅选择的P个不同的步长，也会有多个谱线，很难检测。因此，在本方法中采用子RD图检测目标，可以化简接收侧的处理。
进一步的，当M＝8，m＝8，N＝9，P＝2，S＝1024，Nfft＝1024/8＝128存在两个目标场景时，即Rind上检测2个Vind_sub的情况。如图12所示，为二相位16时隙的总RD中一个距离单元中包含2个目标多普勒谱线的示意图。图12中，总RD图和子RD图的速度分辨率都为dv，但是总RD图的测速范围为8*2*64*dv＝1024*dv，那么子RD图的测速范围为2*64*dv＝128*dv。
子RD图中，经过检测Tx0在多普勒域的峰值索引为Vind＝96或83，子RD图中两个峰间隔是13。
总RD图中，采用局部峰值的方法获得第一大峰值的多普勒索引544＝96+128*3+64；因此匹配到544*dv为第一目标的速度；由于子RD图中两个峰间隔是13，在总RD图第二峰值的多普勒索引不满足该间隔的整数混叠关系，而幅值第三大峰值多普勒索引659上，匹配96-83＝(544-659)+2*128，因此存在第二目标的速度为659*dv。
实际上，这里虽然举例是同一个距离索引Rind上，对应有两个目标的情况。但本申请实施例并不限于此，可以多次迭代，直到匹配的峰值低于预定门限结束。
进一步的，根据速度补偿由于不同时刻引起的多普勒相位差，方法9-1或9-2补偿不同天线间的多普勒相位差。
进一步的，补偿后不同时刻发射的天线的信号是相同时刻发射，天线上的相位差仅由天线的空间上的时延引入的相位差。根据相位差，计算目标的角度信息。由于这里计算和天线的布阵有关系，这里不做特别限制。
进一步的，结合前面的实施例二，在S个时隙之后的S0个时隙中，还包括第三信号时，对应的接收侧执行的步骤，除了步骤806之外，其它步骤都相同，具体可以参考前面的描述。
结合前面的实施例二，前面的步骤806可以采用以下方式实现：
当m根发射天线还在S0个时隙中发送第三信号时，可以通过比较S个时隙中的谱线，和S0个时隙中谱线的位置，确定Tx0在子RD图中多普勒位置，即混叠的速度的多普勒索引Vind_sub，以及目标真实速度，对应的不混叠的速度的多普勒索引Vind_total。
具体的，假设m＝8，N＝9，M＝8，P＝2，S＝S0＝512，发射天线分别为Tx0～Tx8，Tx0发送第一信号，Tx1～Tx8发送第二信号以及第三信号。对前S个时隙中的信号在对应的距离单元求多普勒谱，如图13所示，为本申请实施例提供的一种多普勒谱线示意图。图13中的(c)(图13中的左下图)一共可以获得9个谱线，Tx0发送的信号，以及其他Tx1～Tx8由于时分在谱线上出现的多个混叠后的谱线。如果把后面S0个时隙中的信号对应的距离单元求多普勒谱，可以获得8个谱线，具体可以参考图13中的(d)(图13中的右下图)。由于不存在Tx0的信号，仅在Tx1～Tx8由于时分在谱线上出现的多个混叠后的谱线。那么把这两个谱幅值相减，可以获得目标的速度在256对应的谱线位置，具体可以参考图13中的(b)(图13中的右上图)。图13中的(a)，即图13中的左上图为S+S0个时隙整体求FFT获得的多普勒谱线。
由于第二信号和第三信号的持续时间之和比第一信号的持续时间更长，Tx0发送的信号仅占用前S个时隙，而Tx1～Tx8发送的信号占用S+S0个时隙，因此，实际上存在Tx0 获得的速度分辨率比Tx1～Tx8低，即dv_tx0＝S*dv_txi/(S+S0),其中dv_tx0和dv_txi分别表示Tx0对应的速度分辨率，可以通过简单折算获得实际的目标速度，和目标速度对应的多普勒相位，这里不再赘述。
进一步的，结合前面的实施例三，当P大于2时，接收侧的具体步骤中，除了步骤806和步骤809，其它都相同，下面分别描述步骤806和步骤809。
步骤806：P＝4，抽取子RD图中的Vind、Nfft/4+Vind、Nfft/2+Vind以及3*Nfft/4+Vind的谱线，确定Tx0所在子RD图中的谱线位置，即混叠的速度的多普勒索引Vind_sub。
需要说明的是，这种情况使用总RD图中多根发射天线的信息依靠多普勒也很难分辨。同组内同时发射信号的发射天线Tx1、Tx2以及Tx3的相位为f0-(2*π*ii+Q)/(2*π*M*T SIMO)，f0为Tx0发送的信号的频率。当M＝N-1＝2，P＝4时，那么Q有3个可能的值，即π/2或者π或者3π/2，0相位被Tx0占用，ii有2个可能的取值为0或1，一共有2*3＝6个可能的谱线，加上Tx0所在的谱线，一共有7根谱线。如图11左边第一张图所示。因此，该实施例中，可以通过子RD图辅助目标信息获得Tx0所在的谱线。
具体的，方法一：仅利用子RD图,即步骤805a。比较多个子RD图这P＝4个谱线的幅值差，幅值差较小的为Tx0所在的谱线。
由于多个子RD图中，除了Tx0的通道，其它通道都是时分的，因此，幅值差异较大。图11中，子RD图中Vind＝129的幅值都为256，则Tx0所在谱线位置为129。
方法二：利用总RD图和子RD图，即步骤806。利用子RD图获得该距离单元上目标的个数，在总RD图上采用同一个距离单元上能量最大的谱线，即不混叠的速度的多普勒索引Vind_total，匹配在子RD图上的混叠mod(Vind_total，Nfft)+Nfft/2的位置。根据个数依次迭代谱线和目标个数，从而确定Tx0所在谱线位置。
如图14所示，为本申请实施例提供的一种多普勒谱线示意图。图14示例了4相位8时隙一个距离单元中一个目标的总RD图和子RD图中多普勒谱线。图14中，以总径向速度为0为例，仅0度方向有一个目标的情况为例进行说明。总RD图中有相隔Nfft/4＝64的7个谱线。每个目标在子RD图中有相隔64的4个谱线。其中第一目标的不混叠的速度的多普勒索引Vind_total＝257的能量最高，mod(257，256)+256/2＝129，可以确定多普勒索引位置129为Tx0的谱线。
进一步的，步骤809：补偿Tx1～Txm所在时隙的多普勒频差，以及和Tx0间的固定相位差j、-1以及-j。获得Tx1～Txm天线在不同接收天线上2D-FFT变换后的复信号。
同理，实施例三的例子也可以推广到M为其它取值的情况，例如N≤(P-1)*M+1。同一组(即占用相同时隙发送的天线)内不同天线的相位不同，不同组内间是静默期的位置有循环移位。
进一步的，M为其它取值的情况时，P≥3的情况时，第二信号至少有一组(相同时隙同时发射的天线)中，同时发射天线数小于P-1。
相应的在接收侧，步骤805可以如下所示：
步骤805b：为步骤805a的替代方案，仅用子RD图确定Tx0在子RD图中的多普勒标识的方法。可以采用现有技术类似的，在实施例二中，当P≥3时，如果一个组内(相同时隙同时发射的天线)用仅用集合中部分相位作为步长调制信号，那么，可以采用空缺的相位分辨Tx0的标识。或者P＝2，M大于m/(P-1)的整数时，部分子RD图中，没有占满P个相位调制步长。因此，可以利用某一个子RD图中空缺的相位来辨识Tx0所在的多普 勒谱线位置，即混叠的速度的多普勒索引Vind_sub。
具体的，以P＝4相位的例子中，第一信号在每个周期中发送的信号在P*M个时隙中占用间隔M的P个时隙中相位可以表示为[1,1,1,1]，第二信号在每个周期中发送的信号在P*M个时隙中占用间隔M的P个时隙中相位可以从[1,j,-1,-j],[1,-1,1,-1],[1,-j,-1,j]中选，少于4-1＝3(P＝4)根发射天线同时发射，例如仅用[1,j,-1,-j]，[1,-j,-1,j]发射时，那么f0-fvmax/2的谱线并不存在，可以通过这种方法判断Tx0的正确位置。即仅在f0，f0-fvmax/4，f0-3fvmax/4存在谱线。时分复用的M组天线中，只要有部分组采用这种方式发射就可以在接收侧使用对应时隙的子RD图确定Tx0的谱线位置。同样的，P＝4，M＝2，m＝5,N＝m+1＝6,Tx1～Tx3占用时隙1,3，Tx4～Tx5占用2，4时隙，那么在2,4时隙中仅存在3根发射天线的信号，即Tx0，Tx4,Tx5天线的信号，根据相位调制的步长，可以根据空缺的相位，即P个均匀分布的谱线中有一个缺失的，即f0-fvmax/2的谱线并不存在。
或者可以理解的P＝2，M>m/(P-1)＝m时，第二信号中m个信号，并没有占用S个时隙中的全部时隙，部分时隙中仅存在第一信号。例如，P＝2，N＝3，m＝N-1＝2时，M＝3，那么假设Tx1占用1,4时隙，Tx2占用2,5时隙，而时隙3,6中就仅存在第一信号，即Tx0的信号，第二个信号所在的谱线位置空缺。可以利用时隙3,6的对应的子RD图，确定Tx0的谱线位置。
进一步的，目前，在有些特殊的情况，在子RD图上仅能观察到1对谱线，但从总RD图可以观察到实际有2个目标速度。举例来说，如图15所示，为2相位4时隙一个距离单元中2个子RD图有重叠的目标的总RD图和子RD图中多普勒谱线的示意图。图16中，对应的速度Vind＝59和Vind＝251，对应的两个目标在子RD图中Tx0分别在左边的谱线和右边的谱线，有可能漏掉较弱的目标，例如速度在Vind＝251的目标。
为了解决该问题，可以采用实施例四中的信号发送方法，即第二信号中m根发射天线分成不同组，每组选用不同M i或m i。结合前面实施例四，m根发射天线在S个时隙中采用不同的配置发送第二信号时，在接收侧，前面的步骤803、步骤806以及步骤809可能存在以下不同：
步骤803：分别根据M1和M2抽取多个子RD图。
例如，M1＝2，M2＝3时，如图16所示，为本申请实施例提供的一种多普勒谱线示意图。图16示例了2相位6时隙一个距离单元中2个子RD图在4时隙有多普勒重叠的目标的总RD图和子RD图中多普勒谱线的示意图。
结合图16，利用d vM2＝M1*d vM1/M2折算不同配置的速度标识，具体的，由于M2＝3，而最大测速范围都是单个chirp扫描时间，那么对于用6个时隙的情况下速度分辨率d v6和4个时隙下速度分辨率d v4可以有如下折算关系d v6＝4*d v4/6＝M1*d v4/M2。
步骤806：根据多个不同配置的子RD图和总RD图确定Tx0所在的谱线。
和实施例一不同，取多个子RD图中目标最多的作为目标数。例如，在M1＝2的子RD图中，确定只有一个目标，而在M2＝3的子RD图中，确定有两个目标，那么需要分别寻找两个目标的Tx0所在的谱线。具体的，进一步在利用805和806确定多个目标的Tx0谱线位置。
可以通过发射侧的波形配置，很容易的获得当前距离索引Rind上，是否有多个目标的Tx0混叠到相同或不同的P个位置中的一个。
步骤809：补偿Tx1～Txm所在时隙的多普勒频差。
其中N1根发射天线和N2根发射天线是采用时分方式发送信号的，当设计的N1和N2的总发射时长，满足目标按照最大速度移动也没有超过一个距离单元时，N1根发射天线和N2根发射天线发送的信号反射的目标仍然处于一个距离单元。因此，可以仅考虑相位差别。在车载场景中，可以考虑使得N1根发射天线发送信号的S1个时隙的总时长不超过10ms，N2根发射天线发送信号的S2个时隙的总时长不超过10ms。本申请实施例还提供一种雷达装置，该雷达装置可用于执行图3所示的方法。参见图17，该雷达装置包括天线阵列1701、微波集成电路1702和处理器1703，天线阵列1701包括N根发射天线，N为大于2的整数，其中：
处理器1703，用于确定第一信号和第二信号；
微波集成电路1702，用于生成处理器1703确定的第一信号和第二信号；
天线阵列1701，用于在S个时隙中通过N根发射天线中的1根发射天线发送第一信号；第一信号的相位在S个时隙中不变；在S个时隙中通过N根发射天线中的m根发射天线采用时分方式或码分方式中的至少一种方式发送第二信号；S为大于或等于4的整数；m为大于2的整数，且小于N；第二信号中通过m根发射天线中的每根发射天线发送的信号采用2πk y/P的步长进行相位调制，P为大于1的整数，k y为大于0且小于P的整数，其中k y表示m根发射天线中的第y个发射天线采用的相位调制步长，y＝1,…,m。
可选的，(Nd+1)*P*M>S>＝Nd*P*M，其中Nd表示m根发射天线的发射样式的重复次数，Nd大于或等于1；
发射样式表示采用时分方式的发射天线的信号，占用间隔为M个时隙的不冲突的P个时隙，M为m根发射天线中一根发射天线占用的时隙中的相邻时隙之间相隔的时隙数量，M为大于或等于m/(P-1)的整数。
可选的，m根发射天线中占用相同时隙的发射天线发送的信号采用2πk y/P的步长进行相位调制时，k y取值不同。
可选的，微波集成电路还用于：在S个时隙之后的S0个时隙中，通过m根发射天线采用时分方式发送第三信号，S0为大于1的整数；第三信号在S0个时隙中的发射样式和第二信号在S个时隙中的发射样式相同，S＝Nd*P*M，M为大于或等于m/(P-1)的整数。
可选的，m＝N1+N2，N1>＝2，N2>＝1；微波集成电路具体用于：
在S个时隙中的前S1个时隙，通过m根发射天线中的N1根发射天线以P*M1个时隙为周期，在一个周期的P*M1个时隙中选择不冲突的相隔M1的P个时隙分别发送第二信号；S个时隙中的后S2个时隙，通过m根发射天线中除N1根发射天线之外的N2根发射天线以P*M2个时隙为周期，在一个周期的P*M2个时隙中选择不冲突的相隔M2的P个时隙分别发送第二信号；其中，S＝S1+S2，M1≠M2，M1>＝N1/(P-1)，M2>＝N2/(P-1)。
可选的，P＝2、3或4。
可选的，发送第二信号的m根发射天线与发送第一信号的1根发射天线为N根发射天线中不同的发射天线。
本申请实施例还提供一种雷达装置，该雷达装置可用于执行图7所示的方法。参见图18，该雷达装置包括，雷达装置包括接收器1801和处理器1802，接收器包括至少一根接收天线，其中：
接收器，用于接收回波信号，回波信号是第一信号和第二信号经至少一个目标反射后形成的；其中，第一信号在S个时隙中通过N根发射天线中的1根发射天线发送，第一信 号的相位在S个时隙中不变；第二信号在S个时隙中通过N根发射天线中的m根发射天线采用时分和码分方式中的至少一种方式发送，m为大于或等于2的整数，且小于N；第二信号中通过m根发射天线中的每根发射天线发送的信号采用2πk y/P的步长进行相位调制，P为大于1的整数，k y为大于0且小于P的整数，其中k y表示m根发射天线中的第y个发射天线采用的相位调制步长，y＝1,…,m；S为大于或等于4的整数；
处理器，用于获得至少一根接收天线中每根接收天线的M个子距离-多普勒RD图；其中每根接收天线的M个子RD图中的第i个子RD图，为接收天线在S个时隙的回波信号中起始时隙分别为i，每隔M个时隙的信号二维快速傅里叶变换2D-FFT的结果，i取1,2,…,M的任意整数；根据每根接收天线的M个子RD图累积后的子RD图检测第一目标，并获得该第一目标的距离信息；第一目标为至少一个目标中的一个或多个目标。
可选的，处理器还用于：获得对应总距离-多普勒RD图，总RD图为S个时隙内全部相邻时隙上执行2D-FFT的结果。
可选的，处理器还用于：确定第一目标在累积后的子RD图上第一信号的混叠的速度的至少一个多普勒索引Vind_sub，第一目标在累积后的子RD图上第一信号的混叠的速度的至少一个多普勒索引Vind_sub位于间隔Nfft/P的P个可能位置中，其中Nfft是累积后的子RD图的2D-FFT的维度。
可选的，处理器还用于：根据累积后的子RD图和总RD图进行匹配，确定第一目标的不混叠的速度的至少一个多普勒索引Vind_total，和第一目标在累积后的子RD图上对应的混叠的速度的至少一个多普勒索引Vind_sub。
可选的，处理器还用于：补偿m根发射天线时分引起的多普勒相位偏差和码分引起的相位偏差，并且获得第一目标的角度信息。
本领域内的技术人员应明白，本申请的实施例可提供为方法、系统、或计算机程序产品。因此，本申请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、光学存储器等)上实施的计算机程序产品的形式。
本申请是参照根据本申请的方法、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。
显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本申请的范围。这样，倘若本申请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 (19)

  1. 一种雷达信号发射方法，其特征在于，应用于雷达装置，所述雷达装置包括N根发射天线，N为大于2的整数，所述方法包括：
    在S个时隙中通过所述N根发射天线中的1根发射天线发送第一信号；所述第一信号的相位在所述S个时隙中不变；S为大于或等于4的整数；
    在所述S个时隙中通过所述N根发射天线中的m根发射天线采用时分方式或码分方式中的至少一种方式发送第二信号；m为大于或等于2的整数，且小于N；
    所述第二信号中通过所述m根发射天线中的每根发射天线发送的信号采用2πk y/P的步长进行相位调制，P为大于1的整数，k y为大于0且小于P的整数，其中k y表示所述m根发射天线中的第y个发射天线采用的相位调制步长，y＝1,…,m。
  2. 根据权利要求1所述的方法，其特征在于，(Nd+1)*P*M>S>＝Nd*P*M，其中Nd表示所述m根发射天线的发射样式的重复次数，Nd大于或等于1；
    所述发射样式表示采用时分方式的发射天线的信号占用间隔为M个时隙的不冲突的P个时隙，M为所述m根发射天线中一根发射天线占用的时隙中的相邻时隙之间相隔的时隙数量，M为大于或等于m/(P-1)的整数。
  3. 根据权利要求1所述的方法，其特征在于，所述m根发射天线中占用相同时隙的发射天线发送的信号采用2πk y/P的步长进行相位调制时，k y取值不同。
  4. 根据权利要求1至3任一所述的方法，其特征在于，所述P个相位由包括[0，2π/P，4π/P，6π/P,…,(P-1)*2π/P]相位的移相器产生。
  5. 根据权利要求1至4任一所述的方法，其特征在于，所述方法还包括：
    在所述S个时隙之后的S0个时隙中，通过所述m根发射天线采用时分方式发送第三信号，S0为大于1的整数；
    所述第三信号在S0个时隙中的发射样式和所述第二信号在S个时隙中的发射样式相同，S＝Nd*P*M，M为大于或等于m/(P-1)的整数。
  6. 根据权利要求1所述的方法，其特征在于，所述m＝N1+N2，N1>＝2，N2>＝1；
    所述在所述S个时隙中通过所述N根发射天线中的m根发射天线采用时分方式或码分方式中的至少一种方式发送第二信号，包括：
    在所述S个时隙中的前S1个时隙，通过所述m根发射天线中的N1根发射天线以P*M1个时隙为周期，在一个周期的P*M1个时隙中选择不冲突的相隔M1的P个时隙分别发送所述第二信号；
    在所述S个时隙中的后S2个时隙，通过所述m根发射天线中除所述N1根发射天线之外的N2根发射天线以P*M2个时隙为周期，在一个周期的P*M2个时隙中选择不冲突的相隔M2的P个时隙分别发送所述第二信号；
    其中，S＝S1+S2，M1≠M2，M1>＝N1/(P-1)，M2>＝N2/(P-1)。
  7. 根据权利要求1至6任一所述的方法，其特征在于，所述第一信号在所述S个时隙中的信号波形为调频连续波FMCW；
    所述第二信号在所述S个时隙中的信号波形为FMCW。
  8. 根据权利要求1至7任一所述的方法，其特征在于，所述P＝2、3或4。
  9. 根据权利要求1至8任一所述的方法，其特征在于，发送所述第二信号的所述m 根发射天线与发送所述第一信号的1根发射天线为所述N根发射天线中不同的发射天线。
  10. 一种雷达信号接收方法，其特征在于，应用于雷达装置，所述雷达装置包括N根发射天线以及至少一根接收天线，N为大于2的整数，m为大于或等于2的整数且小于N，所述方法包括：
    获得所述至少一根接收天线中每根接收天线的M个子距离-多普勒RD图；其中所述每根接收天线的M个子RD图中的第i个子RD图，为所述接收天线在S个时隙的回波信号中起始时隙分别为i，每隔M个时隙的信号二维快速傅里叶变换2D-FFT的结果，i取1,2,…,M的任意整数；所述回波信号是第一信号和第二信号经至少一个目标反射后形成的；其中，所述第一信号在S个时隙中通过所述N根发射天线中的1根发射天线发送，所述第一信号的相位在所述S个时隙中不变；所述第二信号在所述S个时隙中通过所述N根发射天线中的m根发射天线采用时分和码分方式中的至少一种方式发送；所述第二信号中通过所述m根发射天线中的每根发射天线发送的信号采用2πk y/P的步长进行相位调制，P为大于1的整数，k y为大于0且小于P的整数，其中k y表示所述m根发射天线中的第y个发射天线采用的相位调制步长，y＝1,…,m；
    根据所述每根接收天线的M个子RD图累积后的子RD图检测第一目标，并获得该第一目标的距离信息；所述第一目标为所述至少一个目标中的一个或多个目标。
  11. 根据权利要求10所述的方法，其特征在于，所述方法还包括：
    获得总距离-多普勒RD图，所述总RD图为S个时隙内全部相邻时隙上执行2D-FFT的结果。
  12. 根据权利要求10所述的方法，其特征在于，所述方法还包括：
    确定所述第一目标在所述累积后的子RD图上第一信号的混叠的速度的至少一个多普勒索引Vind_sub，所述第一目标在所述累积后的子RD图上第一信号的混叠的速度的至少一个多普勒索引Vind_sub位于间隔Nfft/P的P个可能位置中，其中Nfft是所述累积后的子RD图的2D-FFT的维度。
  13. 根据权利要求10或11所述的方法，其特征在于，所述方法还包括：
    根据所述累积后的子RD图和总RD图进行匹配，确定所述第一目标的不混叠的速度的至少一个多普勒索引Vind_total，和所述第一目标在所述累积后的子RD图上对应的混叠的速度的至少一个多普勒索引Vind_sub。
  14. 根据权利要求10所述的方法，其特征在于，所述方法还包括：
    补偿所述m根发射天线时分引起的多普勒相位偏差和码分引起的相位偏差，并且获得第一目标的角度信息。
  15. 一种雷达装置，其特征在于，所述雷达装置包括天线阵列、处理器和微波集成电路，所述天线阵列包括N根发射天线，N为大于2的整数，其中：
    所述处理器，用于确定如权利要求1至9任一所述的第一信号和第二信号；
    所述微波集成电路，用于生成所述处理器确定的所述第一信号和所述第二信号；
    所述天线阵列，用于发送所述微波集成电路生成的所述第一信号和所述第二信号。
  16. 一种雷达装置，其特征在于，所述雷达装置包括接收器和处理器，所述接收器包括至少一根接收天线，其中：
    所述接收器，用于接收如权利要求10至14任一所述的回波信号；
    所述处理器，用于执行如权利要求10至14任一所述的方法。
  17. 一种雷达装置，其特征在于，包括：存储器与处理器，所述存储器用于存储指令，所述处理器用于执行所述存储器存储的指令，并且对所述存储器中存储的指令的执行使得，所述处理器用于执行如权利要求10至14任一所述的方法。
  18. 一种可读存储介质，其特征在于，包括计算机程序或指令，当执行所述计算机程序或指令时，如权利要求1至9或10至14中任意一项所述的方法被执行。
  19. 一种计算机程序产品，其特征在于，包括计算机可读指令，当雷达装置读取并执行所述计算机可读指令，使得所述雷达装置执行如权利要求1至9或10至14中任一项所述的方法。
PCT/CN2020/093630 2020-05-30 2020-05-30 一种雷达信号发射和接收方法及装置 WO2021243491A1 (zh)

Priority Applications (7)

Application Number Priority Date Filing Date Title
PCT/CN2020/093630 WO2021243491A1 (zh) 2020-05-30 2020-05-30 一种雷达信号发射和接收方法及装置
CN202210129330.5A CN114660544A (zh) 2020-05-30 2020-05-30 一种雷达信号发射和接收方法及装置
CN202080004671.9A CN112639507B (zh) 2020-05-30 2020-05-30 一种雷达信号发射和接收方法及装置
EP20939284.4A EP4148451A4 (en) 2020-05-30 2020-05-30 METHOD AND DEVICE FOR TRANSMITTING AND RECEIVING RADAR SIGNAL
CA3180930A CA3180930A1 (en) 2020-05-30 2020-05-30 Radar signal transmitting method, radar signal receiving method, and apparatus
JP2022573474A JP2023527226A (ja) 2020-05-30 2020-05-30 レーダ信号送信方法、レーダ信号受信方法および装置
US18/071,333 US20230092131A1 (en) 2020-05-30 2022-11-29 Radar signal transmitting method, radar signal receiving method, and apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2020/093630 WO2021243491A1 (zh) 2020-05-30 2020-05-30 一种雷达信号发射和接收方法及装置

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US18/071,333 Continuation US20230092131A1 (en) 2020-05-30 2022-11-29 Radar signal transmitting method, radar signal receiving method, and apparatus

Publications (1)

Publication Number Publication Date
WO2021243491A1 true WO2021243491A1 (zh) 2021-12-09

Family

ID=75291176

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/093630 WO2021243491A1 (zh) 2020-05-30 2020-05-30 一种雷达信号发射和接收方法及装置

Country Status (6)

Country Link
US (1) US20230092131A1 (zh)
EP (1) EP4148451A4 (zh)
JP (1) JP2023527226A (zh)
CN (2) CN114660544A (zh)
CA (1) CA3180930A1 (zh)
WO (1) WO2021243491A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114839588A (zh) * 2022-06-27 2022-08-02 珠海正和微芯科技有限公司 Fmcw毫米波雷达接收天线阵误差补偿方法、系统及装置
GB2619075A (en) * 2022-05-27 2023-11-29 Cambridge Sensoriis Ltd Radar

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11876582B2 (en) * 2020-07-20 2024-01-16 Metawave Corporation Hybrid beam steering radar
DE102022121301A1 (de) * 2022-08-23 2024-02-29 Technische Universität Dresden, Körperschaft des öffentlichen Rechts Kognitives Radar zur eindeutigen Messung der Geschwindigkeit
CN117215664A (zh) * 2023-08-21 2023-12-12 白盒子(上海)微电子科技有限公司 一种片上系统多核dsp快速启动方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102362439A (zh) * 2009-01-26 2012-02-22 德雷塞尔大学 用于在mimo系统中选择可重新配置天线的系统和方法
WO2014045096A1 (en) * 2012-09-24 2014-03-27 Adant Technologies, Inc. A method for configuring a reconfigurable antenna system
CN105264400A (zh) * 2013-06-03 2016-01-20 罗伯特·博世有限公司 Fmcw雷达中的干涉抑制
WO2017175190A1 (en) * 2016-04-07 2017-10-12 Uhnder, Inc. Adaptive transmission and interference cancellation for mimo radar
US20180252809A1 (en) * 2016-04-07 2018-09-06 Uhnder, Inc. Software defined automotive radar
CN110168400A (zh) * 2017-01-11 2019-08-23 罗伯特·博世有限公司 用于确定雷达目标的相对速度的雷达传感器和方法
CN110888122A (zh) * 2018-09-10 2020-03-17 英飞凌科技股份有限公司 频率调制连续波雷达系统

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5930366A (en) * 1997-08-29 1999-07-27 Telefonaktiebolaget L M Ericsson Synchronization to a base station and code acquisition within a spread spectrum communication system
CN101409422B (zh) * 2008-11-25 2011-03-30 清华大学 可控多波长激光器
CN107707498A (zh) * 2017-10-09 2018-02-16 中国电子科技集团公司第二十研究所 一种基于相位累积多普勒频偏补偿的0/π调制测角方法
CN109541627A (zh) * 2018-12-25 2019-03-29 西南技术物理研究所 双波长自适应距离门激光雷达

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102362439A (zh) * 2009-01-26 2012-02-22 德雷塞尔大学 用于在mimo系统中选择可重新配置天线的系统和方法
WO2014045096A1 (en) * 2012-09-24 2014-03-27 Adant Technologies, Inc. A method for configuring a reconfigurable antenna system
CN105264400A (zh) * 2013-06-03 2016-01-20 罗伯特·博世有限公司 Fmcw雷达中的干涉抑制
WO2017175190A1 (en) * 2016-04-07 2017-10-12 Uhnder, Inc. Adaptive transmission and interference cancellation for mimo radar
US20180252809A1 (en) * 2016-04-07 2018-09-06 Uhnder, Inc. Software defined automotive radar
CN110168400A (zh) * 2017-01-11 2019-08-23 罗伯特·博世有限公司 用于确定雷达目标的相对速度的雷达传感器和方法
CN110888122A (zh) * 2018-09-10 2020-03-17 英飞凌科技股份有限公司 频率调制连续波雷达系统

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
"Automotive Fast-Chirp MIMO Radar with Simultaneous Transmission in a Doppler-Multiplex", THE 19TH INTER ATIONAL RADAR SYMPOSIUM IRS, 2018
"Automotive Radar Doppler Division MIMO With Velocity Ambiguity Resolving Capabilities", 16TH EUROPEAN RADAR CONFERENCE (EURAD, 2019
See also references of EP4148451A4

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2619075A (en) * 2022-05-27 2023-11-29 Cambridge Sensoriis Ltd Radar
CN114839588A (zh) * 2022-06-27 2022-08-02 珠海正和微芯科技有限公司 Fmcw毫米波雷达接收天线阵误差补偿方法、系统及装置

Also Published As

Publication number Publication date
EP4148451A4 (en) 2023-06-21
US20230092131A1 (en) 2023-03-23
EP4148451A1 (en) 2023-03-15
CN114660544A (zh) 2022-06-24
CA3180930A1 (en) 2021-12-09
CN112639507A (zh) 2021-04-09
JP2023527226A (ja) 2023-06-27
CN112639507B (zh) 2022-07-08

Similar Documents

Publication Publication Date Title
WO2021243491A1 (zh) 一种雷达信号发射和接收方法及装置
Saponara et al. Radar-on-chip/in-package in autonomous driving vehicles and intelligent transport systems: Opportunities and challenges
CN113287036B (zh) 一种速度解模糊的方法及回波信号处理装置
WO2020118582A1 (zh) 信号处理方法及雷达系统、车辆
WO2022020995A1 (zh) 一种信号处理方法、装置以及存储介质
US20210116531A1 (en) Radar apparatus, system, and method of generating angle of arrival (aoa) information
US20220171050A1 (en) Signal transmission method and apparatus, signal processing method and apparatus, and radar system
WO2021189268A1 (zh) 一种雷达信号发射和接收方法及雷达
CN112689964B (zh) 信号传输方法及装置、信号处理方法及装置以及雷达系统
CN109991596A (zh) 用于检测目标的设备和方法
CN111630406B (zh) 确定物体信息项的方法和雷达系统、车辆驾驶员辅助系统
US11988770B2 (en) Phase-modulated continuous wave radar receiver with time division quadrature sampling
WO2021258292A1 (zh) 信号处理方法及装置、雷达装置、存储介质
WO2023142126A1 (zh) 一种探测装置、终端设备及信号处理方法
EP4293389A2 (en) Methods and systems for radar waveform diversity
WO2024066996A1 (zh) 一种雷达信息传输方法、装置和系统
CN114994653A (zh) 拍频信号处理方法及装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20939284

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2022573474

Country of ref document: JP

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 3180930

Country of ref document: CA

ENP Entry into the national phase

Ref document number: 2020939284

Country of ref document: EP

Effective date: 20221205

NENP Non-entry into the national phase

Ref country code: DE