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

Abstract

The embodiment of the application relates to the radar technical field, and discloses a signal processing method, an electronic device 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 transmission channels; processing a return signal to obtain distance-Doppler two-dimensional data; calculating a likelihood probability of a Doppler spectrum under different aliasing combination conditions of transmission channel orders of at least two targets according to the distance-Doppler two-dimensional data; and determining Doppler spectra of the targets according to an aliasing combination corresponding to a maximum value of the likelihood probability. At least, it is beneficial to correctly restore signals before Doppler spectrum aliasing in the presence of at least two targets.

Description

Technical Field

[0001] This application relates to the field of radar technology, and in particular to a signal processing method, storage medium, radar chip, and integrated circuit. Background Technology

[0002] Radar is an electronic device that uses electromagnetic waves to detect targets. Specifically, 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. By processing and analyzing the echo signal, it can 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 echo signals, the Doppler spectrum is obtained by performing range-dimensional Fourier transform and slow-time Fourier transform, and then signal processing is performed based on the Doppler spectrum. However, when at least two targets are present, Doppler spectrum aliasing is likely to occur. If the signal before aliasing cannot be correctly recovered, the targets cannot be detected correctly.

[0004] Therefore, in the presence of at least two targets, it is essential to accurately recover the signal before the Doppler spectrum aliasing. Summary of the Invention

[0005] This application provides a signal processing method, storage medium, radar chip, and integrated circuit, which at least helps to correctly recover the signal before Doppler spectrum aliasing when at least two targets are present.

[0006] This application provides a signal processing method, including: transmitting a detection signal in 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 the transmission channel order of at least two targets includes: traversing all possible combinations of the transmission channel order of at least two targets and calculating the likelihood probability for each of all possible combinations.

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

[0009] In some embodiments, calculating the likelihood probability for each possible combination includes: calculating a least-squares estimate of the energy matrix of each target for each combination based on the energy matrix and the superposition matrix for each combination; and calculating the likelihood probability for each combination based on the energy matrix, the superposition matrix, and the least-squares estimate of the energy matrix of each target. The energy matrix is ​​a matrix obtained based on the energy of the echo signal in each subband of the Doppler spectrum. Each column of the superposition matrix corresponds to a superposition factor for a target, where the element corresponding to the transmission channel order of the target in the superposition factor is 1, and other elements are 0.

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

[0011]

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

[0013]

[0014] Where Q is the number of targets; L is the length of the un-aliased spectral lines in the Doppler spectrum; P′ is the energy of the un-aliased lines, which is an L*1 matrix; The least squares estimates of the energy of each target are given; T represents the transpose; ()-1 represents the inversion operation; M is the superposition matrix, which is an L*Q matrix; m1, m2...m Q represents the superposition factor of each objective; ||…|| represents the modulo operation.

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

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

[0017] In some embodiments, traversing all possible combinations of the transmission channel order of at least two targets includes: traversing all possible combinations of the transmission channel order of targets with 2, 3... subbands minus 1, respectively.

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

[0019] This application also provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program causes the processor to implement the signal processing method described above.

[0020] This application also provides a radar chip, including: at least one processor, and a memory communicatively connected to the at least one processor. The memory stores instructions executable by the at least one processor. The instructions are executed by the at least one processor to enable the at least one processor to perform the signal processing method described above.

[0021] Embodiments of the present invention also provide an integrated circuit, comprising a radio frequency (RF) module, an analog signal processing module, and a digital signal processing module connected in sequence. The RF module transmits a probe signal in Doppler multiplexing (DDM) mode via multiple transmitting antennas and receives echo signals via multiple receiving antennas. The analog signal processing module down-converts the echo signals to obtain intermediate frequency (IF) signals. The digital signal processing module performs analog-to-digital conversion on the IF signals to obtain digital signals, and performs the following processing on the digital signals: performs signal processing on the echo signals to obtain range-Doppler two-dimensional data; calculates the likelihood probability of the Doppler spectrum under different combinations of transmission channel orders for at least two targets; and determines the Doppler spectrum of each target based on the combination corresponding to the maximum likelihood probability.

[0022] Embodiments of the present invention also provide a wireless device, comprising: a carrier, the aforementioned integrated circuit disposed on the carrier, and an antenna disposed on the carrier, or the antenna and the integrated circuit being integrated into a single device disposed on the carrier. The integrated circuit is connected to the antenna and is used to transmit target detection signals and / or receive echo signals.

[0023] Embodiments of the present invention also provide a terminal device, including: a device body, and a wireless device as described above disposed on the device body;

[0024] Among them, wireless devices are used for target detection to provide reference information for the operation of the equipment itself.

[0025] In this embodiment, a maximum likelihood estimation-based algorithm is used to estimate the probabilities of different aliasing combinations. Based on the combination with the highest probability, the spectral lines of multiple targets are separated, and the signal before aliasing can be correctly recovered. This method has low hardware requirements for the radar radio frequency system. Experiments have shown that the solution accuracy is high, the computational load is small, and it has high engineering implementation value. Attached Figure Description

[0026] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

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

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

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

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

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

[0032] Figure 4C for Figure 4A Target 1 and Figure 4B The diagram shows the Doppler spectrum of target 2 after superposition.

[0033] Figure 5 This is a flowchart of a signal processing method according to an embodiment of this application;

[0034] Figure 6 This is a schematic diagram illustrating the likelihood probability of different combinations of launch channel order when the launch channel order of target 1 is H1 and the launch channel order of target 2 is H2.

[0035] Figure 7 This is a statistical diagram of the solution accuracy under the condition that the energy difference between target 1 and target 2 is within 10dB and the different combinations of aliased launch channel order between the targets.

[0036] Figure 8 This is a schematic diagram of the structure of a radar chip according to an embodiment of this application;

[0037] Figure 9 This is a schematic diagram of an integrated circuit structure according to an embodiment of this application. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been presented in the various embodiments of this application to enable readers to better understand this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0039] The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0040] Millimeter-wave radar is a type of radar that operates in the millimeter-wave band, typically ranging from 30 GHz to 300 GHz, with wavelengths from 1 to 10 mm. Figure 1 This is a schematic diagram of a radar structure. The signal generator produces electromagnetic waves with a specific modulation frequency, which are transmitted via an antenna through a transmitter (Tx) and received by a receiver (Rx) from the target. Millimeter-wave radar can simultaneously perform range, velocity, and azimuth measurements on multiple targets. Range measurement is based on the Doppler effect; by calculating the frequency change of the electromagnetic waves returning to the receiving antenna, the target's velocity and flight time relative to the radar are obtained, thus determining the distance between the target and the transmission point. Azimuth measurement (including horizontal and vertical angles) is calculated by measuring the phase difference of electromagnetic waves reflected from the same target by the antenna array, thus determining the target's azimuth relative to the transmission point.

[0041] The signal generator includes, but is not limited to, an oscillator. For example, the oscillator can be a phase-locked loop (PLL) comprising a phase detector, a low-pass filter, and a voltage-controlled oscillator (VCO). The phase detector detects the phase difference between the input and output signals to generate a control voltage, and the VCO adjusts its frequency according to the control voltage, enabling the PLL to provide the same radio frequency (RF) signal for both the input and output signals. The oscillator provides the RF 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 transmission channel. The transmitter amplifies the radio frequency signal provided by the oscillator to obtain the transmitted signal and provides the transmitted signal to the transmitting antenna. The transmitting antenna's function is to convert the waveguide field and the space radiation field, converting the transmitted 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 receiving antenna's function is to convert the spatial radiation field into a waveguide field, thereby obtaining the echo signal. The receiver mixes the echo signal from the receiving channel with a radio frequency signal provided by an oscillator to generate a primary analog signal, and then 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 (ADC).

[0044] A digital signal processor (DSP) includes multiple processing units and storage units for storing intermediate and / or result data. The processing units can be used to perform at least some of the following data processing procedures: Fourier transform, signal processing, angle detection, and point cloud imaging. The Fourier transform can include one-dimensional Fourier transform (e.g., 1D-FFT) and two-dimensional Fourier transform (e.g., 2D-FFT). By performing signal and data processing on the echo signal, the DSP can obtain result data such as the target's distance, velocity, and direction of arrival (DOA).

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

[0046] Millimeter-wave radar transmits waves using various modulation methods. Selecting the appropriate modulation method for different application scenarios can effectively improve system performance and reliability. Frequency Modulated Continuous Wave (FMCW) radar ranging technology is used in high-precision radar ranging. Its transmitted wave is a high-frequency continuous wave, and its frequency changes with time according to a triangular wave law. The continuously changing electromagnetic wave emitted by FMCW radar is reflected by an object to form an echo. This echo and the electromagnetic wave have a certain frequency difference based on the distance between the radar and the object. By detecting the frequency difference, physical quantities between the object and the radar can be measured, such as relative distance, relative velocity, and relative angle. The electrical signal corresponding to the continuously changing electromagnetic wave is called the FMCW signal (or transmitted signal; chirp). Correspondingly, the electrical signal corresponding to the echo is called the echo signal. After the intermediate frequency signal, which is the result of mixing the transmitted signal and the echo signal, is discretely sampled, a range-dimensional Fourier transform is performed on the chirp, and a slow-time Fourier transform (e.g., Doppler-Fast Fourier Transform (Doppler-FFT)) is performed on the chirps. This yields a two-dimensional range-Doppler spectrum, which is then used to detect the range and velocity information between the target and the radar.

[0047] To improve the effective range of millimeter-wave radar, the radar can adopt a Doppler Division Multiple Input Multiple Output (MIMO, or "DDM") tuning mode. In this tuning mode, the radar's transmission channels are activated simultaneously, and different transmission channels modulate different phase steps.

[0048] Figure 2 This is a typical phase diagram of a radar system with four transmit channels and four receive channels (referred to as a "4T4R radar"). The first transmit channel TX0 transmits pulses with a 0° phase step, the second transmit channel TX1 transmits pulses with a 45° phase step, the third transmit channel TX2 transmits pulses with a 180° phase step, and the fourth transmit channel TX3 transmits pulses with a 270° phase step. The echo signal received by each receive antenna includes the signal corresponding to each of the four transmit antennas. Since the phase step of each transmit antenna is fixed, the relative positions of the signals corresponding to each transmit antenna in the echo signal are also fixed.

[0049] The 4T4R radar transmits pulses through four transmission channels and receives echo signals through four reception channels. It performs range-Doppler Fourier transform and Doppler-FFT on the echo signals to obtain the range-Doppler two-dimensional spectrum.

[0050] Figure 3 This is a schematic diagram of the Doppler spectrum of a single target. The horizontal axis represents the number of 2D-FFT Doppler bins, expressed as a unit; the vertical axis represents the 2D-FFT power, expressed as a decibel (dB).

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

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

[0053] However, when at least two targets are present, Doppler spectral aliasing is likely to occur. The following explanation uses two-target Doppler spectral aliasing as an example.

[0054] Figure 4A This is a schematic diagram of the Doppler spectrum for target 1. (Example:) Figure 4A As shown, the TX of target 1 appears in four subbands [0, 1, 4, 6], and the Doppler units are {i, i+ΔD, i+4ΔD, i+6ΔD}. Figure 4B This is a schematic diagram of the Doppler spectrum of target 2. (See diagram below.) Figure 4B As shown, target 2 appears in 4 subbands [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. (Example) Figure 4C As shown, subband 1 of target 1 and subband 0 of target 2 overlap. Therefore, spectral lines exist in subbands [0, 1, 2, 4, 5, 6, 7]. Due to the overlap, the spectral lines no longer satisfy the designed arrangement model (i.e., the interval between spectral lines is no longer [ΔD, 3ΔD, 2ΔD]). This makes it impossible to determine the TX channels corresponding to the two targets, thus preventing the calculation of target velocities and causing problems with subsequent target angle estimation. Figures 4A to 4C In the figure, the horizontal axis represents the two-dimensional fast Fourier transform Doppler units (2D-FFT Dopplerbin), with the unit being the number of units; the vertical axis represents the two-dimensional fast Fourier transform power (2D-FFT power), with the unit being decibels (dB).

[0055] In some cases, the Doppler aliasing of the target can be avoided by using a non-uniform phase modulation design (i.e., phase modulation steps between transmission channels are coprime). However, this technique requires very high phase modulation accuracy, which is often difficult to implement in the radar's radio frequency system, making it too difficult to achieve in engineering.

[0056] This application provides a signal processing method that estimates the probability of different aliasing combinations using a maximum likelihood estimation algorithm. Based on the combination with the highest probability, it separates the spectral lines of multiple targets and recovers the target signals before aliasing. This method has low hardware requirements for the radar radio frequency system. Experiments have shown that it has high accuracy and low computational complexity, making it highly valuable for engineering implementation.

[0057] This application provides a signal processing method applicable to processing modules, devices, or electronic equipment with processing and computing capabilities, such as processing modules in radar or host computers that are communicatively connected to the radar. The radar may be a millimeter-wave radar, etc.

[0058] According to the signal processing method provided in the application embodiments, 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 regions (or, referred to as "sub-bands"), with the number of sub-bands being 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, this application is not limited to the example here, and the minimum phase step value can also be 15°, 30°, 60°, etc.

[0059] The signal processing method provided in the application embodiment has no limitation on the number of transmitting antennas and receiving antennas, and is applicable to MIMO schemes in DDM mode with any number of transmitting antennas and receiving antennas. That is to say, 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 by comprehensively considering factors such as the number of radar antennas, the number of transmitting channels, and the number of receiving channels, in order to meet the system performance requirements of the radar.

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

[0062] In 501, detection signals are transmitted through multiple transmission channels in Doppler multiplexing (DDM) mode.

[0063] This embodiment does not limit the transmitted signal; it can be a continuous wave (CW), a frequency modulated continuous wave (FWCW), etc., which will not be elaborated here.

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

[0065] Signal processing of echo signals 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 procedures: Fourier transform, signal processing, angle detection, and point cloud imaging. The Fourier transform can include one-dimensional FFT (1D-FFT) and two-dimensional FFT (2D-FFT). One-dimensional FFT (1D-FFT) includes, for example, range-dimensional Fourier transform and velocity-dimensional Fourier transform, which can obtain range-dimensional data and velocity-dimensional data respectively. Two-dimensional FFT (2D-FFT) includes, for example, sequential range-dimensional Fourier transform and Doppler-dimensional Fourier transform to obtain range-Doppler two-dimensional data.

[0066] In 503, based on range-Doppler two-dimensional data, the likelihood probability of the Doppler spectrum under different aliasing combinations of the transmission channel order of at least two targets is calculated.

[0067] In 504, the Doppler spectral lines of each target are determined based on 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 to the wall in a conference room, or trees, streetlights, and railings along the roadside. It can also be a dynamic target, such as a moving person or a moving car. Further details will not be elaborated here.

[0069] In some situations, it's impossible to determine how many targets will appear within the radar's detection range. For example, radar is used in intelligent traffic lights, smart signs, and traffic cameras. In these cases, calculating the likelihood probability of the Doppler spectrum for different combinations of transmission channel orders for at least two targets involves: traversing all possible combinations of transmission channel orders for at least two targets and calculating the likelihood probability for each of these combinations. For example, one could traverse all possible combinations of transmission channel orders for targets with 2, 3, ..., the number of subbands minus 1 targets, calculating the likelihood probability for each of these combinations.

[0070] In some situations, the probability of encountering two or three targets within the radar's detection range is relatively high. For example, radar is used in Advanced Driver Assistance Systems (ADAS). In these cases, we can iterate through all possible combinations of the transmission channel order for two targets, or three targets, or both, and calculate the likelihood probability for each combination.

[0071] It is worth noting that after obtaining the range-Doppler two-dimensional data, further processing can be performed to obtain the Doppler spectrum. This processing includes, but is not limited to, detecting targets using Constant False Alarm Rate (CFAR) and further obtaining the Doppler spectrum of each sub-band of the target. Existing methods for processing range-Doppler two-dimensional data to obtain the Doppler spectrum are all applicable and will not be elaborated upon here.

[0072] When the number of peaks in the Doppler spectrum of each sub-band equals the number of transmission channels, the Doppler spectrum can be directly determined as the spectrum of a single target. For example, in Figure 3 In the example, four peaks appear in the Doppler spectrum, which equals the number of transmission channels, and this can be determined. 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 of at least two targets superimposed. For example, in the 4C example, 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. Therefore, it is determined that there may be at least two targets.

[0074] To facilitate a better understanding of the signal processing methods provided in the above embodiments by those skilled in the art, the following will use... Figures 4A to 4C The Doppler spectrum shown is used as an example for illustration.

[0075] exist Figure 2 Under the phase modulation configuration of the transmission channels shown, the possible transmission channel order (TXorder, i.e., the probability of occupying a subband) for a single target is as follows:

[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} Equation (1)

[0084] In radar operation, the detected target velocity can exist in any Doppler cell, meaning the position of TX0 can exist in any subband. Taking the example above where the entire Doppler spectrum is divided into 8 subbands, there are 8 possible positions for TX0 (i.e., its position in the Doppler spectrum of the signal corresponding to TX0). However, since the relative positions of the signals corresponding to each transmitting antenna are determined in the echo signal, if the position of TX0 is determined, the positions of TX1, TX2, and TX3 are also determined. For example... Figure 3 As shown, when the signal corresponding to TX0 is in the first sub-band (sub-band 0) of the Doppler spectrum, the signal corresponding to TX1 is in the second sub-band (sub-band 1) of the Doppler spectrum, the signal corresponding to TX2 is in the fifth sub-band (sub-band 4) of the Doppler spectrum, and the signal corresponding to TX3 is in the seventh sub-band (sub-band 6) of the Doppler spectrum.

[0085] Therefore, when it is uncertain which subband the signal corresponding to TX0 is located in, the possible order of the positions of the signals corresponding to each TX among the eight extracted signals is shown in Equation (1). In Equation (1), the TX order represents the subband to which the signals corresponding to 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 TX5 is in the seventh subband (subband 6).

[0086] Step 1) Calculate the likelihood probability under different possible aliasing combinations. The following example illustrates the case where the transmission channel order of target 1 is H1 and the transmission channel order of target 2 is H2.

[0087] The energy received by the radar for each subband is shown below. Figure 4C As shown, the energy P received by the radar is:

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

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

[0090] Step 2), ignoring (removing) the energy of the aliased signal, assuming the transmission channel order of target 1 is H1 and the transmission channel order of target 2 is H2, ignoring the aliased energy p2, the radar's unaliased energy P′ is obtained as follows:

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

[0092] It is worth noting that aliasing energy has phase, and when the energies are added together, it will cause azimuth ambiguity. Therefore, it is necessary to remove the energy of the aliasing signal.

[0093] Step 3), assuming 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′ Equation (4)

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

[0096]

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

[0098] N is the noise matrix, which represents the noise power received in each subband.

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

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

[0101]

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

[0103] The likelihood probability I is defined as follows: (The question is incomplete and requires further context.)

[0104]

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

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

[0107] Based on the above example, the likelihood probability for each possible combination is calculated, including: (1) calculating the least squares estimate of the energy of each target in the combination based on the energy matrix and the superposition matrix for that combination; and (2) calculating the likelihood probability for that combination based on 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 yet been calculated can be selected from all possible aliasing combinations. For the selected combination, steps (1) and (2) are performed until the likelihood probability is calculated for all possible aliasing combinations. The energy matrix is ​​a matrix obtained based on 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. The element in the superposition factor corresponding to the transmission channel order of the target has a value of 1, and the other elements have a value of 0.

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

[0109] Figure 6 This diagram illustrates the likelihood probabilities of different combinations of transmission channel orders when the transmission channel order of target 1 is H1 and the transmission channel order of target 2 is H2. It is evident that the signal processing method provided in this application can accurately estimate the aliased transmission channel order combinations in the case of dual-target aliasing.

[0110] Figure 7 This diagram illustrates the statistical accuracy of the solution under different combinations of aliased transmission channel orders when the energy difference between target 1 and target 2 is within 10 dB. It is evident that the solution accuracy of the signal processing method provided in this application is higher than 96%.

[0111] Those skilled in the art should understand that the signal processing method provided in the embodiments of this application is not limited to the above-described 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 embodiments of this application can be used to estimate the aliasing transmission channel order combination.

[0112] When the target quantity is Q, the unaltered energy P' is an L*1 matrix, the superposition matrix M is an L*Q matrix, A1, A2, ..., A Q The least squares estimate is:

[0113]

[0114] The likelihood probability I is defined as:

[0115]

[0116] In step 503, when calculating the likelihood probability of the Doppler spectrum under various possible aliasing combinations, one can first assume the number of targets is 2 and calculate the likelihood probability of various possible aliasing combinations for two targets, then assume the number of targets is 3 and calculate the likelihood probability of various possible aliasing combinations for three targets, and so on, until assuming the number of targets is the number of sub-bands - 1, and calculating the likelihood probability of various possible aliasing combinations for sub-bands - 1 targets. In step 504, the aliasing combination corresponding to the maximum value of all calculated likelihood probabilities is found. However, the embodiments of this application are not limited to this, and the likelihood probabilities of all possible aliasing combinations can be calculated in any order.

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

[0118]

[0119] The steps of the various methods described above are only for clarity. In practice, they can be combined into one step or some steps can be split 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 or introducing insignificant designs to the algorithm or process, but without changing the core design of the algorithm and process, are also within the scope of protection of this patent.

[0120] Another aspect of this application embodiment also provides a radar chip, such as... Figure 8 As shown, it includes: at least one processor 801; and a memory 802 communicatively connected to at least one processor 801; wherein the memory 802 stores instructions executable by at least one processor 801, the instructions being executed by at least one processor 801 to enable at least one processor 801 to perform the signal processing method described in any of the above method embodiments.

[0121] The memory 802 and processor 801 are connected via a bus, which can include any number of interconnecting buses and bridges. The bus connects various circuits of one or more processors 801 and 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 therefore will not be described further herein. A bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by processor 801 is transmitted over a wireless medium via an antenna, which further receives data and transmits it to 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 during operation.

[0123] Another aspect of this application provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the signal processing method provided in any of the above-described method embodiments.

[0124] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

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

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

[0127] Computer-readable storage media may include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable storage medium may also be any readable medium other than a readable storage medium that can transmit, propagate, or transfer a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.

[0128] Program code for performing the operations of this application can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0129] The aforementioned computer-readable medium carries one or more programs, which, when executed by a device, enable the computer-readable medium to perform the aforementioned functions.

[0130] Another embodiment of the present invention relates to an integrated circuit, such as Figure 9 As shown, the system includes a radio frequency (RF) module 901, an analog signal processing module 902, and a digital signal processing module 903 connected in sequence. The RF module 901 transmits a probe signal in Doppler-dimensional multiplexed (DDM) mode via multiple transmitting antennas and receives echo signals via multiple receiving antennas. The analog signal processing module 902 down-converts the echo signal to obtain an intermediate frequency (IF) signal. The digital signal processing module 903 performs analog-to-digital conversion on the IF signal to obtain a digital signal, and performs the following processing on the digital signal: performs signal processing on the echo signal to obtain range-Doppler two-dimensional data; calculates the likelihood probability of the Doppler spectrum under different combinations of transmission channel orders for at least two targets based on the range-Doppler two-dimensional data; and determines the Doppler spectrum of each target based on the combination corresponding to the maximum likelihood probability.

[0131] Another embodiment of the present invention relates to a wireless device, comprising: a carrier, the aforementioned integrated circuit disposed on the carrier, and an antenna disposed on the carrier, or the antenna and the integrated circuit being integrated into a single device disposed on the carrier. The integrated circuit is connected to the antenna and is used to transmit target detection signals and / or receive echo signals.

[0132] When the antenna and integrated circuit are not integrated into a single device, the integrated circuit is connected to the antenna via a first transmission line, which can be a PCB trace. The carrier can be a printed circuit board (PCB), such as a development board, data acquisition board, or the motherboard of a device, etc., which will not be elaborated on here.

[0133] Since the structure and working principle of the integrated circuits included in the wireless devices have been described in detail in the above embodiments, they will not be repeated here.

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

[0135] In one embodiment of this application, the wireless device may be disposed outside the device body. In another embodiment, the wireless device may be disposed inside the device body. In still other embodiments, the wireless device may be partially disposed inside the device body and partially disposed outside the device body. This application does not limit the specific implementation; the choice depends on the circumstances.

[0136] It should be noted that wireless devices can achieve functions such as target detection by transmitting and receiving radio signals, thereby providing the device body with measurement information of the detected target, and thus assisting or even controlling the operation of the device body. Examples of such measurement information include at least one of relative distance, relative speed, and relative angle.

[0137] In an optional embodiment, the aforementioned device body can be a component or product applied in fields such as transportation, consumer electronics, monitoring, in-cabin detection, and healthcare. For example, the device body can be intelligent transportation equipment (such as automobiles, motorcycles, ships, subways, trains, etc.), security equipment (such as cameras), liquid level / flow rate detection equipment, smart wearable devices (such as wristbands, glasses, etc.), smart home devices (such as robot vacuum cleaners, door locks, televisions, air conditioners, smart lights, etc.), various communication devices (such as mobile phones, tablets, etc.), as well as devices such as barriers, intelligent traffic lights, intelligent signs, traffic cameras, and various industrial robotic arms (or robots). It can also be various instruments used to detect vital signs parameters and various devices equipped with such instruments, such as in-cabin detection in automobiles, indoor personnel monitoring, intelligent medical devices, and consumer electronic devices.

[0138] In another alternative embodiment, when the aforementioned device body is applied to an advanced driver assistance system (i.e., ADAS), the wireless device, as an on-board sensor, can provide various functional safety guarantees for the ADAS system, such as automatic brake assist (i.e., AEB), blind spot detection warning (i.e., BSD), lane change assist warning (i.e., LCA), and reversing assist warning (i.e., RCTA).

[0139] Furthermore, the examples mentioned in the above embodiments can be freely combined, and any combination can be understood as an embodiment. The terms "embodiment" or "example" appearing in various locations in the specification do not necessarily refer to the same embodiment, nor are they independent or alternative embodiments mutually exclusive with other embodiments. Those skilled in the art will understand that the embodiments described herein can be combined with other embodiments.

[0140] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing this application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of this application.

Claims

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

2. The signal processing method according to claim 1, characterized in that, The calculation of the likelihood probability of the Doppler spectrum under different aliasing combinations of the transmission channel order of at least two targets includes: Iterate through all possible combinations of the launch channel order of the at least two targets and calculate the likelihood probability for each of the possible combinations.

3. The signal processing method according to claim 2, characterized in that, The possible combinations of the order of the launch channels for traversing the at least two targets include at least one of the following: Iterate through the possible combinations of the launch channel order for the two targets, and Possible combinations of the launch channel order for the three targets.

4. The signal processing method according to claim 2 or 3, characterized in that, The calculation of the likelihood probability for each of the possible combinations includes: Based on the energy matrix and the superposition matrix for each combination, calculate the least squares estimate of the energy matrix of each target for each combination. Based on the energy matrix, the superposition matrix, and the least squares estimate of the energy matrix of each target, calculate the likelihood probability for each combination case; The energy matrix is ​​a matrix obtained based on the energy of the echo signal in each sub-band of the Doppler spectrum; In this superposition matrix, each column corresponds to a superposition factor of a target, and the element in the superposition factor corresponding to the target's transmission channel order has a value of 1, while the other elements have a value of 0.

5. The signal processing method according to claim 4, characterized in that, The least-squares estimate of the energy of each objective under each combination is calculated using the following formula: The likelihood probability for each combination of cases is calculated using the following formula: Where Q is the number of targets; L is the length of the un-aliased spectral lines in the Doppler spectrum; P' is the un-aliased energy matrix, which is an L*1 matrix; , ... These are the least squares estimates of the energy matrices of each target; T represents the transpose; ()-1 is the inversion operation; M is the superposition matrix, which is an L*Q matrix; , ... This is the superposition factor for each objective; For modulo 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 subbands of the Doppler spectrum are divided according to the non-zero minimum phase step value of the reference transmission channel among the plurality of transmission channels, and the number of subbands 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 traversal of all possible combinations of the launch channel order of the at least two targets includes: Iterate through all possible combinations of the transmission channel order of the target when the number of targets is 2, 3, ..., and the number of sub-bands is -1.

9. The signal processing method according to claim 1, characterized in that, The signal processing method further includes: Before calculating the likelihood probability of the Doppler spectrum for different combinations of transmission channel orders for 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 the processor, it implements the signal processing method as described in any one of claims 1 to 9.

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 to enable the at least one processor to perform the signal processing method as described in 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 Doppler multiplexing (DDM) mode through multiple transmitting antennas and to receive echo signals through multiple receiving antennas. The analog signal processing module is used to down-frequency 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 to perform the following processing on the digital signal: The echo signal is processed to obtain range-Doppler two-dimensional data; Based on the 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; The Doppler spectrum of each target is determined based on the combination corresponding to the maximum value of the likelihood probability.

13. A wireless device, characterized in that, include: Carrier; The integrated circuit as described in claim 12 is disposed on the carrier at its location; An antenna is disposed on the carrier, or the antenna and the integrated circuit are integrated into a single device and disposed on the carrier. The integrated circuit is connected to the antenna and is used to transmit the detection signal and / or receive the echo signal.

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

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