Signal processing method, storage medium, radar chip and integrated circuit

Abstract

The embodiment of the invention relates to the technical field of radar, and discloses a signal processing method, electronic equipment and a storage medium. The signal processing method comprises the following steps: transmitting a detection signal in a Doppler multiplexing DDM mode through a plurality of transmitting channels; processing the echo signal to obtain distance-Doppler two-dimensional data; according to the distance-Doppler two-dimensional data, calculating likelihood probabilities of Doppler spectrums under different aliasing combination conditions of emission channel sequences of at least two targets; and according to the aliasing combination corresponding to the maximum value of the likelihood probability, determining the Doppler spectrum of each target. The method is at least beneficial to correct recovery of signals before Doppler spectrum aliasing in the presence of at least two targets.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of radar technology, and in particular to a signal processing method, a storage medium, a radar chip, and an integrated circuit. Background Art

[0002] Radar is an electronic device that uses electromagnetic waves to detect targets. Specifically, the radar first emits electromagnetic waves to illuminate the target, and then receives the echo signal generated by the reflection of the emitted electromagnetic waves by the target. It can then process and analyze the echo signal to obtain information such as the distance from the target to the electromagnetic wave emission point, the rate of change of distance (radial velocity), azimuth, and altitude.

[0003] When processing and analyzing the echo signal, the echo signal is transformed into the distance dimension and the slow time dimension to obtain the Doppler spectrum, and then the signal is processed according to the Doppler spectrum. However, when there are at least two targets, Doppler spectrum aliasing is likely to occur. If the signal before aliasing cannot be correctly restored, the target cannot be correctly detected.

[0004] Therefore, when there are at least two targets, it is urgent to correctly restore the signal before Doppler spectrum aliasing. Summary of the invention

[0005] The embodiments of the present application provide a signal processing method, a storage medium, a radar chip, and an integrated circuit, which are at least helpful in correctly restoring the signal before Doppler spectrum aliasing when at least two targets exist.

[0006] An embodiment of the present application provides a signal processing method, including: transmitting a detection signal in a Doppler multiplexing DDM mode through multiple transmission channels; processing the echo signal to obtain range-Doppler two-dimensional data; calculating the likelihood probability of the Doppler spectrum under different aliasing combinations of the transmission channel order of at least two targets based on the range-Doppler two-dimensional data; and determining the Doppler spectrum of each target based on the combination corresponding to the maximum value of the likelihood probability.

[0007] In some embodiments, calculating the likelihood probability of the Doppler spectrum under different aliasing combinations of transmission channel orders of at least two targets includes: traversing all possible combinations of transmission channel orders of at least two targets, and calculating the likelihood probability of each combination of all possible combinations.

[0008] In some embodiments, traversing all possible combinations of the transmission channel order of the at least two targets includes at least one of the following: traversing possible combinations of transmission channel orders for two targets, and traversing possible combinations of transmission channel orders for three targets.

[0009] In some embodiments, the likelihood probability of each combination of all possible combinations is calculated, including: calculating the least squares estimate of the energy matrix of each target in each combination according to the energy matrix and the superposition matrix of each combination; calculating the likelihood probability of each combination according to the energy matrix, the superposition matrix, and the least squares estimate of the energy matrix of each target. Wherein, the energy matrix is ​​a matrix obtained according to the energy of the echo signal in each sub-band of the Doppler spectrum. Each column of the superposition matrix corresponds to the superposition factor of a target, and the element value corresponding to the transmission channel order of the target in the superposition factor is 1, and the other element values ​​are 0.

[0010] In some embodiments, the least squares estimate of the energy of each target in each combination is calculated by the following formula:

[0011]

[0012] The likelihood probability for each combination is calculated by the following formula:

[0013]

[0014] Where Q is the number of targets; L is the length of the unaliased line in the Doppler spectrum; P′ is the unaliased energy, which is an L*1 matrix; are the least squares estimates of the energy of each target; T represents transposition; ()-1 represents the inverse operation; M is the superposition matrix, which is an L*Q matrix; m1, m2...m Q is the superposition factor of each target; ||…|| is the modulo operation.

[0015] In some embodiments, the sub-bands of the Doppler spectrum are divided according to non-zero minimum phase step values ​​of the multiple transmission channels relative to the reference transmission channel, and the number of sub-bands is greater than the number of transmission antennas.

[0016] In some embodiments, the minimum phase modulation step value is any one of 15°, 30°, 45°, and 60°.

[0017] In some embodiments, traversing all possible combinations of transmit channel orders of at least two targets includes: traversing all possible combinations of transmit channel orders of 2, 3, ... the number of sub-bands-1 targets respectively.

[0018] In some embodiments, the signal processing method further includes: before calculating the likelihood probabilities of the Doppler spectrum under different combinations of transmission channel orders of the at least two targets, determining that the number of Doppler spectrum peaks is greater than the number of transmission channels.

[0019] The embodiment of the present application further provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the processor implements the signal processing method as described above.

[0020] The embodiment of the present application also provides a radar chip, comprising: at least one processor, and a memory connected to the at least one processor in communication. The memory stores instructions that can be executed by the at least one processor. The instructions are executed by the at least one processor so that the at least one processor can perform the signal processing method as described above.

[0021] An embodiment of the present invention also provides an integrated circuit, comprising a radio frequency module, an analog signal processing module and a digital signal processing module connected in sequence. The radio frequency module is used to transmit a detection signal in a Doppler multiplexing DDM mode through multiple transmitting antennas, and receive an echo signal through multiple receiving antennas. The analog signal processing module is used to perform frequency reduction processing on the echo signal to obtain an intermediate frequency signal. The digital signal processing module is used to perform analog-to-digital conversion on the intermediate frequency signal to obtain a digital signal, and perform the following processing on the digital signal: perform signal processing on the echo signal to obtain range-Doppler two-dimensional data; calculate the likelihood probability of the Doppler spectrum under different combinations of the transmission channel order of at least two targets; determine the Doppler spectrum of each target according to the combination corresponding to the maximum value of the likelihood probability.

[0022] An embodiment of the present invention further provides a radio device, comprising: a carrier, the above-mentioned integrated circuit disposed on the carrier, and an antenna disposed on the carrier, or the antenna and the integrated circuit are integrated into a device disposed on the carrier. The integrated circuit is connected to the antenna for transmitting a target detection signal and / or receiving an echo signal.

[0023] An embodiment of the present invention further provides a terminal device, comprising: a device body, and the above-mentioned radio device arranged on the device body;

[0024] Among them, the radio device is used for target detection to provide reference information for the operation of the equipment body.

[0025] In the embodiment of the present application, the probability of different aliasing combinations is estimated by using an algorithm based on maximum likelihood estimation, and the spectrum lines of multiple targets are separated according to the combination with the maximum probability, so that the signal before the target aliasing can be correctly restored. This method does not have high hardware requirements for the radar RF system. Experiments have shown that the accuracy of the solution is high, the amount of calculation is small, and it has a high engineering implementation value. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0027] Figure 1 is a schematic diagram of a radar structure according to an embodiment of the present application;

[0028] Figure 2 is a typical phase diagram of a 4T4R radar according to an embodiment of the present application;

[0029] Figure 3 is a schematic diagram of the Doppler spectrum of a single target according to an embodiment of the present application;

[0030] Figure 4A is a schematic diagram of a Doppler spectrum of target 1 according to an embodiment of the present application;

[0031] Figure 4B is a schematic diagram of a Doppler spectrum of target 1 according to an embodiment of the present application;

[0032] Figure 4C for Figure 4A Target 1 and Figure 4B The schematic diagram of Doppler spectrum of target 2 after superposition is shown;

[0033] Figure 5 is a flow chart of a signal processing method according to an embodiment of the present application;

[0034] Figure 6 It is a schematic diagram of the likelihood probability of different combinations of emission channel orders estimated when the emission channel order of target 1 is H1 and the emission channel order of target 2 is H2;

[0035] Figure 7 This is a statistical diagram of the accuracy of the solution when the energy difference between target 1 and target 2 is within 10dB and the order combination of different aliasing transmission channels between targets;

[0036] Figure 8 is a schematic structural diagram of a radar chip according to an embodiment of the present application;

[0037] Fig. 9 is a schematic diagram of an integrated circuit structure according to an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in the embodiments of the present application, many technical details are provided in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can be implemented.

[0039] The division of the following embodiments is for the convenience of description and shall not constitute any limitation on the specific implementation of the present application. The embodiments may be combined with each other and referenced to each other without contradiction.

[0040] Millimeter wave radar is a radar that works in the millimeter wave band for detection. The frequency band is generally 30GHz to 300GHz and the wavelength is 1 to 10mm. Figure 1 It is a schematic diagram of the radar structure. Among them, the signal generator generates electromagnetic waves of a specific modulation frequency, sends the electromagnetic waves through the antenna via the transmitter Tx, and receives the electromagnetic waves reflected from the target through the antenna via the receiver Rx. Millimeter wave radar can measure the distance, speed and azimuth of multiple targets at the same time. The distance measurement is based on the Doppler effect. By calculating the frequency change of the electromagnetic waves returned to the receiving antenna, the movement speed and flight time of the target relative to the radar are obtained, thereby obtaining the distance between the target and the launch point. Azimuth measurement (including horizontal angle and vertical angle) is to calculate the azimuth of the target relative to the launch point by receiving the phase difference of the electromagnetic waves reflected by the same target through the antenna array.

[0041] The signal generator includes, but is not limited to, an oscillator. For example, the oscillator may be a phase-locked loop including a phase detector, a low-pass filter, and a voltage-controlled oscillator. The phase detector detects the phase difference between the input signal and the output signal to generate a control voltage. The voltage-controlled oscillator adjusts the frequency according to the control voltage so that the phase-locked loop can provide a radio frequency signal with the same input signal and output signal. The oscillator provides the radio frequency signal to the transmitter Tx and the receiver Rx.

[0042] The transmitter Tx is connected to an antenna (e.g., a transmitting antenna) to form a transmitting channel. The transmitter amplifies the power of the RF signal provided by the oscillator to obtain a transmitting signal, and provides the transmitting signal to the transmitting antenna. The function of the transmitting antenna is to convert the waveguide field and the spatial radiation field, and convert the transmitting signal into a radar beam radiated into the surrounding environment.

[0043] The receiver Rx is connected to an antenna (e.g., a receiving antenna) to form a receiving channel. In the presence of obstacles in the surrounding environment, the receiving antenna can receive the echo of the radar beam. The function of the receiving antenna is to convert the spatial radiation field and the waveguide field to obtain the echo signal. The receiver mixes the echo signal of the receiving channel with the radio frequency signal provided by the oscillator to generate a primary analog signal, and converts the primary analog signal into an analog input signal. The analog input signal is converted into a digital signal by an analog to digital converter (Analog to Digital Converter, referred to as "ADC").

[0044] The digital signal processor (DSP) includes multiple processing units and a storage unit for storing intermediate data and / or result data. The multiple processing units can be used to perform at least part of the following data processing processes: Fourier transform, signal processing, angle detection, and point cloud imaging. Among them, the Fourier transform can include a one-dimensional Fourier transform (e.g., 1D-FFT) and a two-dimensional Fourier transform (e.g., 2D-FFT). The digital signal processor performs signal processing and data processing on the echo signal, and can obtain result data such as the distance, speed, and angle of arrival (DOA) of the target.

[0045] The angular resolution, angular accuracy, and angular robustness of the radar are directly related to the number of receiving channels and the aperture of the radar. Due to the limitation of the radar size and the number of physical transmitting / receiving channels of the millimeter-wave radar chip, a multiple-input multiple-output (MIMO) radar is generally used to expand the number of receiving channels and the aperture. From the perspective of the different angles of the transmitted detection signal, the signal processing methods of MIMO radar include signal processing methods based on time division multiplexing (TDM) and signal processing methods based on Doppler division multiplexing (DDM).

[0046] There are many types of modulation methods for millimeter wave radar transmission waves. Choosing the appropriate modulation method in different application scenarios can effectively improve system performance and reliability. Frequency Modulated Continuous Wave (FMCW) radar ranging technology is a technology used in high-precision radar ranging. Its transmission wave is a high-frequency continuous wave, and its frequency changes over time according to the law of triangular waves. The electromagnetic wave with a continuously changing frequency emitted by the FMCW radar is reflected by the object to form an echo. The echo and the electromagnetic wave have a certain frequency difference based on the distance between the radar and the object. The detection of the frequency difference can realize the measurement of physical quantities between the object and the radar, such as relative distance information, relative speed information, relative angle information and other physical quantities. Among them, the electrical signal corresponding to the electromagnetic wave with a continuously changing frequency is called an FMCW signal (or a transmitting signal; chirp). Correspondingly, the electrical signal corresponding to the echo is called an echo signal. After discrete sampling, the intermediate frequency signal after mixing the transmitted signal and the echo signal is subjected to a range-dimensional Fourier transform inside the chirp, and a slow-time Fourier transform is performed between the chirps (for example, Doppler-Fast Fourier Transform (abbreviated as "Doppler-FFT")), so that a two-dimensional spectrum of range-Doppler can be obtained, and the distance and speed information between the target and the radar can be detected.

[0047] In order to increase the effective range of millimeter-wave radar, the radar can adopt the Doppler Division Multiple Input Multiple Output (MIMO) (DDM) debugging mode. In this debugging mode, the radar's transmit channels are turned on at the same time, and different transmit channels modulate different phase steps.

[0048] Figure 2 The following is a typical phase diagram of a radar with four transmitting channels and four receiving channels (referred to as "4T4R radar"). Among them, the first transmitting channel TX0 transmits pulses according to the phase step of 0°, the second transmitting channel TX1 transmits pulses according to the phase step of 45°, the third transmitting channel TX2 transmits pulses according to the phase step of 180°, and the fourth transmitting channel TX3 transmits pulses according to the phase step of 270°. The echo signal received by each receiving antenna includes the signals corresponding to the four transmitting antennas. Since the phase step of each transmitting antenna is determined, the relative position of the signal corresponding to each transmitting antenna in the echo signal is determined.

[0049] The 4T4R radar sends transmit pulses through four transmit channels respectively, receives echo signals through four receive channels respectively, performs range-dimensional Fourier transform and Doppler-FFT on the echo signals, and obtains a two-dimensional range-Doppler spectrum.

[0050] Figure 3 The figure is a schematic diagram of the Doppler spectrum of a single target. The horizontal axis is the two-dimensional fast Fourier transform Doppler unit (2D-FFT Doppler bin), the unit is unit; the vertical axis is the two-dimensional fast Fourier transform power (2D-FFT power), the unit is decibel (dB).

[0051] If the entire Doppler spectrum is divided into 8 regions (or, called "sub-bands"), then the transmission signals of TX0, TX1, TX2, and TX3 may appear on sub-bands [0, 1, 4, 6], and the Doppler units are: {i, i+ΔD, i+4ΔD, i+6ΔD}, where i is the Doppler unit where the TX0 spectrum line is located, and ΔD is the Doppler interval between sub-bands. It can be seen that since the Doppler spectrum of a single target has 4 spectral lines, the order of the transmission channels corresponding to the 4 spectral lines can be determined according to the design arrangement model of the 4 spectral lines (for example, the intervals are [ΔD, 3ΔD, 2ΔD]).

[0052] For example, taking the entire Doppler spectrum being divided into 8 sub-bands as an example, since the Doppler spectrum includes 512 Doppler units, after the Doppler spectrum is equally spaced into 8 sub-bands, each sub-band includes 64 Doppler units, and the number of Doppler units between any two adjacent signal intervals is the same. For example, the transmit signal of TX0 may appear in a Doppler unit with a value of 1, then the transmit signal of TX1 may appear in a Doppler unit with a value of 1+64, the transmit signal of TX2 may appear in a Doppler unit with a value of 1+64×4, and the transmit signal of TX2 may appear in a Doppler unit with a value of 1+64×6.

[0053] However, when there are at least two targets, Doppler spectrum aliasing is likely to occur. The following is an explanation of the dual-target Doppler spectrum aliasing.

[0054] Figure 4A is a schematic diagram of the Doppler spectrum of target 1. Figure 4A As shown, the TX of target 1 appears in 4 sub-bands [0, 1, 4, 6], and the Doppler units are: {i, i+ΔD, i+4ΔD, i+6ΔD}. Figure 4B is a schematic diagram of the Doppler spectrum of target 2. Figure 4B As shown, target 2 appears in 4 sub-bands [1, 2, 5, 7], and the Doppler units are: {i+ΔD, i+2ΔD, i+5ΔD, i+7ΔD}. Figure 4CThis is a schematic diagram of the Doppler spectrum after the superposition of target 1 and target 2. Figure 4C As shown in the figure, subband 1 of target 1 and subband 0 of target 2 are aliased. Therefore, there are spectral lines in subbands [0, 1, 2, 4, 5, 6, 7]. Due to the occurrence of aliasing, the spectral lines no longer meet the design arrangement model (that is, the interval between the spectral lines is no longer [ΔD, 3ΔD, 2ΔD]). In this way, the TX channels corresponding to the two targets cannot be determined, that is, the speed of the target cannot be solved, and the angle estimation of the subsequent target is also problematic. Among them, FIG. 4A to FIG. 4C In the figure, the horizontal axis is the two-dimensional fast Fourier transform Doppler unit (2D-FFT Dopplerbin), and the unit is unit; the vertical axis is the two-dimensional fast Fourier transform power (2D-FFT power), and the unit is decibel (dB).

[0055] In some cases, the Doppler aliasing of the target can be avoided by non-uniform phase modulation design (i.e., phase modulation step mutual prime between transmit channels). However, this technology has very high requirements on phase modulation accuracy, which is often difficult to achieve in the radar's RF system and the engineering implementation is too difficult.

[0056] The embodiment of the present application provides a signal processing method, which estimates the probability of different aliasing combinations through an algorithm based on maximum likelihood estimation, separates the spectrum lines of multiple targets according to the combination with the maximum probability, and restores the signal before the target aliasing. The method does not have high hardware requirements for the radar RF system. Experiments have shown that the accuracy of the solution is high, the amount of calculation is small, and it has a high engineering implementation value.

[0057] The embodiment of the present application provides a signal processing method, which is applied to a processing module in a radar, a host computer connected to the radar, or other modules, devices, or electronic devices with processing and computing capabilities. The radar may be a millimeter wave radar, etc.

[0058] According to the signal processing method provided in the embodiment of the application, the DDM debugging method is adopted, the non-zero minimum phase step value of the radar is Dph, and the entire Doppler spectrum is divided into 360 / Dph areas (or, called "sub-bands"), and the number of sub-bands is greater than the number of transmitting antennas. For example, the minimum phase step value is 45°, the entire Doppler spectrum is divided into 8 sub-bands, and the number of days is 4. However, the application is not limited to the examples here, and the minimum phase step value can also be 15°, 30°, 60°, etc.

[0059] According to the signal processing method provided in the embodiment of the application, there is no restriction on the number of transmitting antennas and the number of receiving antennas, and it is applicable to the MIMO scheme of the DDM mode with any number of transmitting antennas and receiving antennas. In other words, the radar is not limited to the 4T4R radar mentioned above, but can also be a 3T4R radar, a 6T8R radar, or an 8T8R radar.

[0060] The minimum phase step value can be determined based on comprehensive considerations such as the number of radar antennas, the number of transmitting channels, the number of receiving channels, etc., to meet the system performance requirements of the radar.

[0061] Figure 5 A flowchart of a signal processing method provided for an embodiment of the application.

[0062] In 501, a detection signal is transmitted through a plurality of transmission channels in a Doppler multiplexing DDM mode.

[0063] This embodiment does not limit the transmission signal, which may be a continuous wave (CW) or a frequency modulated continuous wave (FWCW), etc., which will not be described in detail here.

[0064] In 502, the echo signal is processed to obtain range-Doppler two-dimensional data.

[0065] The signal processing of the echo signal includes analog signal processing and digital signal processing. Analog signal processing includes mixing and converting the echo signal to obtain an analog input signal. Digital signal processing includes converting the analog input signal into a digital signal and performing multiple data processing processes: Fourier transform, signal processing, angle detection and point cloud imaging. Among them, Fourier transform can include one-dimensional FFT transform (1D-FFT) and two-dimensional FFT transform (2D-FFT). One-dimensional FFT transform (1D-FFT) includes, for example, distance dimension Fourier transform and velocity dimension Fourier transform, which can obtain distance dimension data and velocity dimension data respectively. Two-dimensional FFT transform (2D-FFT) includes, for example, distance dimension Fourier transform and Doppler dimension Fourier transform performed successively to obtain distance-Doppler two-dimensional data.

[0066] In 503, the likelihood probabilities of Doppler spectra under different aliasing combinations of transmission channel orders of at least two targets are calculated based on the range-Doppler two-dimensional data.

[0067] In 504, the Doppler spectrum line of each target is determined according to the combination corresponding to the maximum value of the likelihood probability.

[0068] This embodiment does not limit the type of target. It can be a static target, such as a display screen fixed on the wall in a conference room, trees, street lights, and railings on the roadside. It can also be a dynamic target, such as a moving person, a moving car, etc. It will not be described here one by one.

[0069] In some cases, it is uncertain how many targets will appear within the radar's detection range. For example, radars are used in devices such as smart traffic lights, smart signs, and traffic cameras. In these cases, the likelihood probabilities of Doppler spectra under different combinations of transmission channel orders of at least two targets are calculated, including: traversing all possible combinations of transmission channel orders of at least two targets, and calculating the likelihood probabilities of each combination in all possible combinations. For example, all possible combinations of transmission channel orders of 2, 3, ..., the number of sub-bands - 1 targets can be traversed respectively, and the likelihood probabilities of each combination in all possible combinations can be calculated.

[0070] In some cases, there is a high probability that two or three targets appear within the detection range of the radar. For example, the radar is used in advanced driver assistance systems (ADAS). In these cases, the possible combinations of the transmission channel order of two targets can be traversed, or the possible combinations of the transmission channel order of three targets can be traversed, or the possible combinations of the transmission channel order of two and three targets can be traversed, and the likelihood probabilities under various combinations can be calculated.

[0071] It is worth noting that after obtaining the range-Doppler two-dimensional data, further processing can be performed to obtain the Doppler spectrum. The processing mentioned here includes, but is not limited to, obtaining the target through constant false alarm rate (CFAR) detection, and further obtaining the Doppler spectrum of each sub-band of the target. Existing methods for processing the range-Doppler two-dimensional data to obtain the Doppler spectrum are applicable, so they will not be described in detail here.

[0072] When the number of peaks in the Doppler spectrum of each sub-band is equal to the number of transmit channels, the Doppler spectrum can be directly determined as the spectrum of a single target. Figure 3 In the example, there are 4 peaks in the Doppler spectrum, which is equal to the number of transmit channels. Figure 3 The spectrum shown is that of a single target.

[0073] When the number of peaks in the Doppler spectrum of each sub-band is greater than the number of transmission channels, it can be determined that there are at least two targets, that is, the Doppler spectrum is determined to be the Doppler spectrum after the superposition of at least two targets. For example, in the example of 4C, in the Doppler spectrum, there are peaks in sub-bands [0, 1, 2, 4, 5, 6, 7], and the number of peaks is 7, which is greater than the number of transmission channels 4, so it is determined that there may be at least two targets.

[0074] To facilitate those skilled in the art to better understand the signal processing method provided by the above embodiment, FIG. 4A to FIG. 4C The Doppler spectrum shown is used as an example for explanation.

[0075] exist Figure 2 In the case of the transmission channel phase modulation configuration shown in FIG, the possible transmission channel order (abbreviated as “TXorder”, i.e., the possibility of occupying a subband) of a single target is

[0076] H0: {S0, S1, S4, S6}

[0077] H1: {S1, S2, S5, S7}

[0078] H2: {S2, S3, S6, S0}

[0079] H3: {S3, S4, S7, S1}

[0080] H4: {S4, S5, S0, S2}

[0081] H5: {S5, S6, S1, S3}

[0082] H6: {S6, S7, S2, S4}

[0083] H7: {S7, S0, S3, S5} Formula (1)

[0084] In radar operation, the speed of the detected target may exist in any Doppler unit (Dopplerbin), that is, the position of TX0 may exist in any sub-band. Taking the above example of dividing the entire Doppler spectrum into 8 sub-bands, there are 8 possible TX0 positions (that is, the position in the Doppler spectrum of the signal corresponding to TX0). Since the relative positions of the signals corresponding to each transmitting antenna are determined in the echo signal, when the position of TX0 is determined, the positions of TX1, TX2 and TX3 are also determined. Figure 3 As shown, when the signal corresponding to TX0 is in the first subband (subband 0) in the Doppler spectrum, the signal corresponding to TX1 is in the second subband (subband 1) in the Doppler spectrum, the signal corresponding to TX2 is in the fifth subband (subband 4) in the Doppler spectrum, and the signal corresponding to TX3 is in the seventh subband (subband 6) in the Doppler spectrum.

[0085] Therefore, in the case of uncertainty about which subband the signal corresponding to TX0 is located in, the possible position order of the signals corresponding to each TX in the extracted 8 signals is shown in equation (1). The TX order in equation (1) indicates the subband to which the signals corresponding to each of the four transmitting antennas belong. For example, in possibility 1 (H0), the signal corresponding to TX0 is in the first subband (subband 0), the signal corresponding to TX1 is in the second subband (subband 1), the signal corresponding to TX3 is in the fifth subband (subband 4), and the signal corresponding to TX3 is in the seventh subband (subband 6).

[0086] Step 1) calculates the likelihood probabilities under different possible aliasing combinations, and takes the transmission channel order of target 1 as H1 and the transmission channel order of target 2 as H2 as an example for explanation.

[0087] The energy of each sub-band received by the radar is shown in Figure 4C As shown, the energy P received by the radar is:

[0088] P=[p0, p1, p2, p3, p4, p5, p6, p7] T Formula (2)

[0089] In formula (2), P is a one-dimensional vector, p i Corresponding to Figure 4C The energy of the i-th subband in , i = 0, 1, 2, 3...7; T represents transpose.

[0090] Step 2), ignore (remove) the energy of the aliased signal. Assuming that the transmission channel order of target 1 is H1 and the transmission channel order of target 2 is H2, ignore the aliased energy p2, and obtain the radar unaliased energy P′:

[0091] P′=[p0,p1,p3,p4,p s , p6, p7] T Formula (3)

[0092] It is worth noting that the aliased energy has a phase. When the energy is added, it will cause azimuth ambiguity. Therefore, it is necessary to remove the energy of the aliased signal.

[0093] Step 3), assuming that the energy of target 1 is A1 and the energy of target 2 is A2, then P′ can be expressed as:

[0094] M[A1 A2]+N=P′ Formula (4)

[0095] Where M is the superposition matrix assuming that the transmission channel order of target 1 is H1 and the transmission channel order of target 2 is H2:

[0096]

[0097] m1 is the superposition factor when the transmission channel order of target 1 is H1. Since the transmission channel order of target 1 is H1: {S1, S2, S5, S7}, S2 is removed, so the element values ​​corresponding to S1, S5, S7 are 1, and the other element values ​​are 0. m2 is the superposition factor when the transmission channel order of target 2 is H2. Similarly, since the transmission channel order of target 2 is H2: {S2, S3, S6, S0}, S2 is removed, so the element values ​​corresponding to S3, S6, S0 are 1, and the other element values ​​are 0.

[0098] N is the noise matrix, which is the noise power received by each sub-band.

[0099] N=[n0, n1, n3, n4, n5, n6, n7] T Formula (6)

[0100] Then, the least squares estimates of A1 and A2 are:

[0101]

[0102] In formula (7), are the least squares estimates of A1 and A2 respectively, () -1 To perform the inverse operation.

[0103] The likelihood probability I when the transmission channel order of target 1 is H1 and the transmission channel order of target 2 is H2 is defined as:

[0104]

[0105] Where L is the length of the unaliased spectral line. For example, Figure 4C In the example, the length of the unaliased line is 7. It can be seen that the length of the unaliased line is the same as the number of elements in P'. ||…|| is the modulo operation.

[0106] Step 4), repeat step 3), traverse all possible combinations of the transmission channel order of the two targets, find the combination with the largest likelihood probability I, and select the unaliased spectral lines of the two targets under this combination (i.e. Figure 4A and Figure 4B ), which is used for subsequent angle estimation.

[0107] According to the above example, the likelihood probability of each combination in all possible combinations is calculated, including: (1) calculating the least squares estimate of the energy of each target in the combination according to the energy matrix and the superposition matrix of the combination, and (2) calculating the likelihood probability of the combination according to the energy matrix, the superposition matrix, and the least squares estimate of the energy of each target. Specifically, a combination whose likelihood probability has not been calculated can be selected from all possible aliasing combinations, and (1) and (2) are executed for the selected combination until the likelihood probability is calculated for all possible aliasing combinations. Among them, the energy matrix is ​​a matrix obtained according to the energy of the echo signal in each subband of the Doppler spectrum. Each column of the superposition matrix corresponds to the superposition factor of a target, and the element value corresponding to the transmission channel order of the target in the superposition factor is 1, and the other element values ​​are 0.

[0108] The sub-bands of the Doppler spectrum are divided according to the minimum phase step value relative to the reference transmission channel among the multiple transmission channels, and the number of the sub-bands is greater than the number of transmission antennas.

[0109] Figure 6 Schematic diagram of likelihood probability of different estimated transmission channel order combinations when the transmission channel order of target 1 is H1 and the transmission channel order of target 2 is H2. It can be seen that the signal processing method provided in the embodiment of the present application can correctly estimate the aliased transmission channel order combination in the case of dual-target aliasing.

[0110] Figure 7 The figure is a statistical diagram of the accuracy of the solution when the energy difference between target 1 and target 2 is within 10 dB and the order combination of different aliased transmission channels between targets. It can be seen that the accuracy of the solution of the signal processing method provided in the embodiment of the present application is higher than 96%.

[0111] Those skilled in the art should understand that the signal processing method provided in the embodiment of the present application is not limited to the above-mentioned dual-target aliasing situation. When the number of targets is greater than or equal to 2, or less than the number of sub-bands, the signal processing method provided in the embodiment of the present application can be used to estimate the aliasing transmission channel order combination.

[0112] When the number of targets is Q, the unaliased energy P' is an L*1 matrix, and the superposition matrix M is an L*Q matrix, A1, A2...A Q The least squares estimate of is:

[0113]

[0114] The likelihood probability I is defined as:

[0115]

[0116] In 503, when calculating the likelihood probabilities of the Doppler spectrum under various possible aliasing combinations, it can be assumed that the number of targets is 2, and the likelihood probabilities under various possible aliasing combinations of two targets can be calculated. Then, it can be assumed that the number of targets is 3, and the likelihood probabilities under various possible aliasing combinations of three targets can be calculated. This can be deduced by analogy until the number of targets is assumed to be the number of sub-bands-1, and the likelihood probabilities under various possible aliasing combinations of the number of sub-bands-1 targets are calculated. In 504, the aliasing combination corresponding to the maximum value of all the calculated likelihood probabilities is found. However, the embodiments of the present application are not limited thereto, and the likelihood probabilities under all possible aliasing combinations can be calculated in any order.

[0117] For example, when the number of targets is 3, assuming that the transmission channel order of target 1 is H1: {S1, S2, S5, S7}, the transmission channel order of target 2 is H2: {S2, S3, S6, S0}, and the transmission channel order of target 3 is H3: {S3, S4, S7, S1}, after removing the aliased energy p1, p2, p7, the unaliased energy P' is: P' = [p0, p4, p5, p6]T , the superposition matrix M is:

[0118]

[0119] The step division of the above methods is only for the purpose of clear description. When implemented, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent; adding insignificant modifications to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process are all within the scope of protection of this patent.

[0120] On the other hand, the present application embodiment also provides a radar chip, such as Figure 8 As shown, it includes: at least one processor 801; and a memory 802 that is communicatively connected to the at least one processor 801; wherein the memory 802 stores instructions that can be executed by the at least one processor 801, and the instructions are executed by the at least one processor 801 so that the at least one processor 801 can execute the signal processing method described in any of the above method embodiments.

[0121] The memory 802 and the processor 801 are connected in a bus manner, and the bus may include any number of interconnected buses and bridges, and the bus connects various circuits of one or more processors 801 and the memory 802 together. The bus can also connect various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be one element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices on a transmission medium. The data processed by the processor 801 is transmitted on a wireless medium via an antenna, and further, the antenna also receives data and transmits the data to the processor 801.

[0122] The processor 801 is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management and other control functions. The memory 802 can be used to store data used by the processor 801 when performing operations.

[0123] Another aspect of the present application embodiment further provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the signal processing method provided by any of the above method embodiments is implemented.

[0124] Those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0125] The technical solution according to the implementation mode of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes a number of instructions to enable a computing device (which can be a personal computer, a server, or a network device, etc.) to execute the above method according to the implementation mode of the present application.

[0126] The software product may use any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination thereof. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0127] Computer readable storage media may include data signals propagated in baseband or as part of a carrier wave, wherein readable program codes are carried. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The readable storage medium may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or device. The program codes contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination thereof.

[0128] Program code for performing the operations of the present application may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0129] The computer-readable medium carries one or more programs. When the one or more programs are executed by a device, the computer-readable medium implements the aforementioned functions.

[0130] Another embodiment of the present invention relates to an integrated circuit, such as Fig. 9 As shown, it includes a radio frequency module 901, an analog signal processing module 902 and a digital signal processing module 903 connected in sequence. The radio frequency module 901 is used to transmit a detection signal in a Doppler dimension multiplexing DDM mode through multiple transmitting antennas, and receive an echo signal through multiple receiving antennas. The analog signal processing module 902 is used to perform frequency reduction processing on the echo signal to obtain an intermediate frequency signal. And, the digital signal processing module 903 is used to perform analog-to-digital conversion on the intermediate frequency signal to obtain a digital signal, and perform the following processing on the digital signal: perform signal processing on the echo signal to obtain range-Doppler two-dimensional data; calculate the likelihood probability of the Doppler spectrum under different combinations of the transmission channel order of at least two targets according to the range-Doppler two-dimensional data; determine the Doppler spectrum of each target according to the combination corresponding to the maximum value of the likelihood probability.

[0131] Another embodiment of the present invention relates to a radio device, comprising: a carrier, the above-mentioned integrated circuit disposed on the carrier, and an antenna disposed on the carrier, or the antenna and the integrated circuit are integrated into a device disposed on the carrier. The integrated circuit is connected to the antenna for transmitting a target detection signal and / or receiving an echo signal.

[0132] When the antenna and the integrated circuit are not integrated into one device, the integrated circuit is connected to the antenna through a first transmission line, and the first transmission line can be a PCB trace. The carrier can be a printed circuit board PCB, such as a development board, a data acquisition board or a main board of a device, etc., which will not be described in detail here.

[0133] Since the structure and working principle of the integrated circuit included in the radio device have been described in detail in the above embodiments, they will not be described in detail here.

[0134] Another embodiment of the present invention relates to a terminal device, comprising: a device body; and a radio device as described above, which is arranged on the device body; wherein the radio device is used for target detection to provide reference information for the operation of the device body.

[0135] In one embodiment of the present application, the radio device may be disposed outside the device body, in another embodiment of the present application, the radio device may also be disposed inside the device body, and in other embodiments of the present application, the radio device may also be partially disposed inside the device body and partially disposed outside the device body. The present application embodiment does not limit this, and it depends on the specific situation.

[0136] It should be noted that the radio device can realize functions such as target detection by transmitting and receiving radio signals to provide the device body with measurement information of the detected target, thereby assisting or even controlling the operation of the device body. The measurement information includes, for example, at least one of relative distance, relative speed, and relative angle.

[0137] In an optional embodiment, the device body may be a component or product used in fields such as transportation, consumer electronics, monitoring, in-cabin detection, and health care. For example, the device body may be intelligent transportation equipment (such as automobiles, motorcycles, ships, subways, trains, etc.), security equipment (such as cameras), liquid level / flow rate detection equipment, intelligent wearable devices (such as bracelets, glasses, etc.), smart home devices (such as sweeping robots, door locks, televisions, air conditioners, smart lights, etc.), various communication devices (such as mobile phones, tablet computers, etc.), and gates, intelligent traffic lights, intelligent signs, traffic cameras, and various industrialized robotic arms (or robots), etc. It may also be various instruments for detecting life characteristic parameters and various equipment equipped with the instruments, such as in-cabin detection of automobiles, indoor personnel monitoring, intelligent medical equipment, consumer electronic equipment, etc.

[0138] In another optional embodiment, when the above-mentioned device body is applied to an advanced driver assistance system (i.e., ADAS), the radio device as a vehicle-mounted sensor can provide various functional safety guarantees for the ADAS system such as automatic braking assistance (i.e., AEB), blind spot detection warning (i.e., BSD), lane change assistance warning (i.e., LCA), and reversing assistance warning (i.e., RCTA).

[0139] In addition, the examples mentioned in the above embodiments can be freely combined, and any combination can be understood as an embodiment. The "embodiment" or "example" appearing in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It can be understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0140] Those skilled in the art will appreciate that the above embodiments are specific embodiments for implementing the present application, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present application.

Claims

1. A signal processing method, characterized in that: include: Transmitting a detection signal through multiple transmission channels in a Doppler multiplexing DDM mode; Process the echo signal to obtain range-Doppler two-dimensional data; Calculating the likelihood probability of Doppler spectrum under different aliasing combinations of transmission channel orders of at least two targets according to the range-Doppler two-dimensional data; The Doppler spectrum of each target is determined according to the combination corresponding to the maximum value of the likelihood probability.

2. The signal processing method according to claim 1, characterized in that: The method of calculating the likelihood probability of the Doppler spectrum under different aliasing combinations of the transmission channel orders of at least two targets comprises: All possible combinations of the transmission channel orders of the at least two targets are traversed, and the likelihood probability of each combination in all possible combinations is calculated.

3. The signal processing method according to claim 2, characterized in that: All possible combinations of the transmission channel order of the at least two targets are traversed, including at least one of the following: possible combinations of the order of the transmission channels for the two targets, and The possible combinations of the order of the launch channels for the three targets are traversed.

4. The signal processing method according to claim 2 or 3, characterized in that: The calculating the likelihood probability of each combination in all possible combinations includes: Calculate the least squares estimate of the energy matrix of each target in each combination case according to the energy matrix and the superposition matrix in each combination case; Calculating the likelihood probability of each combination according to the energy matrix, the superposition matrix, and the least squares estimate of the energy matrix of each target; Wherein, the energy matrix is ​​a matrix obtained according to the energy of the echo signal in each sub-band of the Doppler spectrum; Each column of the superposition matrix corresponds to a superposition factor of a target, and the element value of the superposition factor corresponding to the transmission channel order of the target is 1, and the other element values ​​are 0.

5. The signal processing method according to claim 4, characterized in that: The least squares estimate of the energy of each target in each combination is calculated by the following formula: The likelihood probability for each combination is calculated by the following formula: Wherein, Q is the number of targets; L is the length of the unaliased spectral line in the Doppler spectrum; P' is the unaliased energy matrix, which is an L*1 matrix; are the least squares estimates of the energy matrices of each target; T represents transposition; ()-1 represents the inverse operation; M is the superposition matrix, which is an L*Q matrix; m1, m2…m Q is the superposition factor of each target; ||…|| is the modulus operation; The unaliased energy matrix is ​​obtained by removing the energy of the aliased signal from the energy matrix.

6. The signal processing method according to claim 4, characterized in that: The sub-bands of the Doppler spectrum are divided according to a non-zero minimum phase step value relative to a reference transmission channel among the multiple transmission channels, and the number of the sub-bands is greater than the number of transmission antennas.

7. The signal processing method according to claim 6, characterized in that: The minimum phase step value is any one of 15°, 30°, 45°, and 60°.

8. The signal processing method according to claim 2, characterized in that: The traversing all possible combinations of the transmission channel order of the at least two targets includes: All possible combinations of the transmission channel order of 2, 3, ..., the number of sub-bands-1 target are traversed respectively.

9. The signal processing method according to claim 1, characterized in that: The signal processing method further includes: Before calculating the likelihood probabilities of the Doppler spectra in different combinations of transmission channel orders of at least two targets, it is determined that the number of Doppler spectrum peaks is greater than the number of transmission channels.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the signal processing method according to any one of claims 1 to 9 is implemented.

11. A radar chip, characterized in that: include: at least one processor; as well as, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the signal processing method according to any one of claims 1 to 9.

12. An integrated circuit, characterized in that: It includes a radio frequency module, an analog signal processing module and a digital signal processing module connected in sequence; The radio frequency module is used to transmit detection signals in a Doppler multiplexing DDM mode through multiple transmitting antennas, and receive echo signals through multiple receiving antennas; The analog signal processing module is used to perform frequency reduction processing on the echo signal to obtain an intermediate frequency signal; and The digital signal processing module is used to perform analog-to-digital conversion on the intermediate frequency signal to obtain a digital signal, and perform the following processing on the digital signal: Processing the echo signal to obtain range-Doppler two-dimensional data; Calculating the likelihood probability of Doppler spectrum under different combinations of transmission channel orders of at least two targets according to the range-Doppler two-dimensional data; The Doppler spectrum of each target is determined according to the combination corresponding to the maximum value of the likelihood probability.

13. A radio device, characterized in that: include: Carrier; The integrated circuit as claimed in claim 12, disposed on a carrier; An antenna is arranged on the carrier, or the antenna and the integrated circuit are integrated into one device and arranged on the carrier; Wherein, the integrated circuit is connected to the antenna and is used for transmitting the detection signal and / or receiving the echo signal.

14. A terminal device, characterized in that: include: Equipment body; as well as The radio device according to claim 13 is arranged on the device body; Wherein, the radio device is used for target detection to provide reference information for the operation of the device body.

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