Radar noise floor estimation method, device, storage medium and terminal equipment

Abstract

The present invention discloses a radar noise floor estimation method, device, storage medium, and terminal device, belonging to the field of radar detection technology. The method comprises: S100, dividing a number of frequency points according to the signal bandwidth occupied by the radar during operation to form a set s; S200, selecting each frequency point in the set s, transmitting and receiving echo signals according to a preset method, and obtaining the corresponding echo signal matrix R t (k); S300, low-frequency filtering and / or DC component suppression are performed on each echo signal matrix, and a fast Fourier transform is performed; S400, all obtained fast Fourier transform sequences are energy-combined to obtain the radar noise floor power. The present invention can concentrate the energy of moving target interference in the environment near zero frequency, filter out the interference through low-frequency filtering and other processing methods, and then fully suppress the moving target interference through fast Fourier transform to estimate the radar noise floor power, thereby improving the efficiency of noise floor estimation.

Description

Technical Field

[0001] The present invention belongs to the field of radar detection technology, and in particular relates to a radar noise floor estimation method, device, storage medium and terminal equipment. Background Art

[0002] As a target perception sensor, radar is widely used in the intelligent Internet of Things (IoT). Accurately and efficiently acquiring radar noise floor power is a key technology for radar target detection. Existing noise floor estimation techniques are typically based on two-dimensional fast Fourier transforms.

[0003] Specifically, existing noise floor estimation techniques, based on a two-dimensional fast Fourier transform (FFT), discard signal energy in areas where moving target echoes are likely to be distributed in the Doppler dimension before calculating the noise floor power of the radar's range spectrum or range-Doppler spectrum. However, in the presence of strong moving target interference in the radar operating environment, existing noise floor estimation techniques are susceptible to interference from moving target echoes and suffer from poor robustness. Summary of the Invention

[0004] The present invention provides a radar noise floor estimation method, apparatus, storage medium, and terminal device, which aims to improve the anti-interference capability and stability of radar noise floor estimation by estimating the noise floor of the radar range spectrum. The technical solution for implementing the present invention is as follows:

[0005] In a first aspect, the present invention provides a radar noise floor estimation method, comprising:

[0006] S100, dividing a number of frequency points according to the signal bandwidth occupied by the radar during operation to form a set s;

[0007] S200, select each frequency point in the set s, transmit and receive echo signals according to the preset method, and obtain the corresponding echo signal matrix R t (k), k represents the kth frequency point in the set s, t = 1, 2, ..., T, T represents the number of radar receiver channels;

[0008] S300, for each echo signal matrix R t (k) performing low-frequency filtering and / or DC component suppression, and performing fast Fourier transform;

[0009] S400: Perform energy merging processing on all obtained fast Fourier transform sequences to obtain the radar noise floor power.

[0010] As a specific technical solution, when dividing the frequency points in step S100, the number of frequency points is determined in combination with the signal bandwidth occupied by the radar during operation and the hardware circuit characteristics of the radar transmitter and receiver. The basic principles for dividing the frequency points include at least one of the following: the smaller the bandwidth occupied by the radar during operation, the smaller the number of frequency points; the worse the consistency of the in-band gain and noise figure characteristics of the hardware circuit of the radar transmitter and receiver, the larger the number of frequency points.

[0011] As a specific technical solution, in step S100:

[0012] When the radar is an SFCW radar, the set s is equal to the set consisting of all ready-to-transmit radio frequency points of the SFCW radar;

[0013] When the radar is an FMCW radar, frequency points are selected at equal intervals based on the signal bandwidth occupied by the radar during operation. The set s is expressed as {f0+μ*h*Ts, h = 0, 1, 2, ..., H-1}. Here, f0 is the starting frequency of the FMCW radar frequency sweep, μ is the sweep slope of the FMCW radar, Ts is the ADC sampling rate of the FMCW radar receiver, and H is the total number of signal samples collected by the radar receiver ADC during a radar signal waveform transmission when the FMCW radar is operating normally.

[0014] As a specific technical solution, in step S200, the preset method is specifically as follows: for the kth frequency point in the set s, the radar performs a total of M signal transmission processes. During each transmission process, the radar transmits a single tone signal fixed at the kth frequency point, and the tth receiver channel of the radar receives and samples the echo signal to obtain N sampled output signals; M*N sampled output signals are accumulated to form the echo signal matrix R t (k); where the nth sampled output signal of the mth transmission and the tth receiver channel is R t The element in the nth row and mth column of (k), n = 1, 2, ..., N; m = 1, 2, ..., M; t = 1, 2, ..., T; T represents the number of radar receiver channels.

[0015] As a preferred technical solution, when executing step S200, between two adjacent transmission processes, the radar is shut down and then turned on once.

[0016] As a specific technical solution, in step S300, the specific method of performing low-frequency filtering on each echo signal matrix includes:

[0017] Perform high-pass filtering in the fast time dimension and transform the echo signal matrix R t The elements of the mth column of (k) are fed into the filter in sequence, and the output sequence of the filter is used as the updated R t (k) the mth column element; or,

[0018] Perform high-pass filtering in the slow time dimension and transform the echo signal matrix R t The elements of the nth row of (k) are fed into the filter in sequence, and the output sequence of the filter is used as the updated R t (k) The element in row n;

[0019] The filter transfer function is H(z) = (1 - z -1 ) / (1-ɑ*z -1 ), z represents the complex frequency domain variable of the discrete-time system, and ɑ is the preset filter coefficient.

[0020] As a specific technical solution, in step S300, the specific method of suppressing the DC component of each echo signal matrix includes:

[0021] In the fast time dimension, the echo signal matrix R t Each element of the mth column of (k) is subtracted from the mean of the mth column, and the output sequence is used as the updated R t (k) the mth column element; or,

[0022] In the slow time dimension, the echo signal matrix R t Each element in the nth row of (k) is subtracted from the mean of the nth row, and the output sequence is used as the updated R t (k) The element in the nth row of

[0023] As a preferred technical solution, in step S300, the specific method of performing fast Fourier transform includes:

[0024] For the echo signal matrix after low-frequency filtering and / or DC component suppression, elements in the same column are selected for windowing and then a one-dimensional fast Fourier transform is performed.

[0025] As a preferred technical solution, the radar noise floor estimation method further includes:

[0026] S500 , averaging the energy of elements with the same Fourier transform sequence number in all obtained fast Fourier transform sequences to obtain radar range spectrum noise floor power.

[0027] As a preferred technical solution, the radar noise floor estimation method further includes:

[0028] S600 : Perform gain conversion on the obtained radar range spectrum noise floor power to obtain the radar's range-velocity spectrum noise floor power, range-velocity spectrum-angle spectrum noise floor power, and / or range-angle spectrum noise floor power.

[0029] In a second aspect, the present invention provides a radar noise floor estimation device, comprising:

[0030] The frequency point set acquisition module divides several frequency points into a set s according to the signal bandwidth occupied by the radar during operation;

[0031] The echo signal matrix generation module selects each frequency point in the set s, transmits and receives the echo signal according to the preset method, and obtains the corresponding echo signal matrix R t (k);

[0032] The data processing module processes each echo signal matrix R t (k) performing low-frequency filtering and / or DC component suppression, and performing fast Fourier transform;

[0033] The radar noise floor power acquisition module combines the energy of all the obtained fast Fourier transform sequences to obtain the radar noise floor power.

[0034] As a preferred technical solution, the radar noise floor estimation device further includes:

[0035] The radar range spectrum noise floor power acquisition module averages the energy of elements with the same Fourier transform sequence number in all the obtained fast Fourier transform sequences to obtain the radar range spectrum noise floor power.

[0036] As a preferred technical solution, the radar noise floor estimation device further includes:

[0037] The gain conversion module performs gain conversion on the obtained radar range spectrum noise floor power to obtain the radar's range-velocity spectrum noise floor power, range-velocity spectrum-angle spectrum noise floor power, and / or range-angle spectrum noise floor power.

[0038] In a third aspect, the present invention further provides a storage medium storing a plurality of instructions, wherein the instructions are suitable for being loaded by a processor and executing the method steps of the above-mentioned radar noise floor estimation method.

[0039] In a fourth aspect, the present invention further provides a terminal device comprising: a processor and a memory; the memory stores a computer program, and the computer program is suitable for being loaded by the processor and executing the method steps of the above-mentioned radar noise floor estimation method.

[0040] The beneficial effects brought about by the technical solution of the present invention include at least: the present invention constructs a frequency point set s and then transmits the frequency points through a preset transmission method, thereby concentrating the energy of the interference of moving targets in the environment near the zero frequency, and filtering the influence of the interference through processing methods such as low-frequency filtering. There is no need to filter the influence of the interference echo signal through a conventional two-dimensional FFT method. Only a one-dimensional FFT method can be used to fully suppress the interference of moving targets, estimate the noise floor power of the radar, and the noise floor power of the range spectrum or range-velocity spectrum, thereby improving the anti-interference capability, stability and efficiency of the noise floor estimation. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 This is a flowchart of a basic implementation of a radar noise floor estimation method provided by an embodiment of the present invention.

[0043] Figure 2 This is a flowchart of a preferred implementation of the radar noise floor estimation method provided by an embodiment of the present invention.

[0044] Figure 3 This is a flowchart of another preferred implementation of the radar noise floor estimation method provided by an embodiment of the present invention.

[0045] Figure 4 4 is a block diagram of a basic implementation of a radar noise floor estimation device provided by an embodiment of the present invention.

[0046] Figure 5 This is a module structure diagram of a preferred implementation of the radar noise floor estimation device provided by an embodiment of the present invention.

[0047] Figure 6 This is a module structure diagram of another preferred implementation of the radar noise floor estimation device provided by an embodiment of the present invention.

[0048] Figure 7 It is a structural diagram of a terminal device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0049] To make the technical solution of the present invention clearer and the technical advantages more apparent, the technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of the present invention.

[0050] It should be noted that, in this document, the terms "comprise," "include," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or also includes elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of other identical elements in the process, method, article, or apparatus comprising the element. In addition, components, features, and elements with the same name in different embodiments of the present application may have the same meaning or different meanings, and their specific meanings shall be determined by their explanation in the specific embodiment or further in conjunction with the context of the specific embodiment.

[0051] It should be understood that, although the various steps in the flowchart in the embodiment of the present application are shown in sequence according to the indication of the arrows, these steps are not necessarily performed in sequence in the order indicated by the arrows. Unless clearly stated herein, the execution of these steps is not strictly limited in order, and they can be performed in other orders. Moreover, at least a portion of the steps in the figure may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and their execution order is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0052] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0053] An embodiment of the present invention provides a radar noise floor estimation method. The execution entity of the radar noise floor estimation method can be the radar noise floor estimation device provided in the embodiment of the present invention, or an intelligent terminal and server integrating the radar noise floor estimation device, wherein the radar noise floor estimation device can be implemented in hardware or software.

[0054] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0055] like Figure 1 As shown, as a basic implementation method, the radar noise floor estimation method provided in this embodiment includes:

[0056] S100, dividing a number of frequency points according to the signal bandwidth occupied by the radar during operation to form a set s;

[0057] S200, select each frequency point in the set s, transmit and receive echo signals according to the preset method, and obtain the corresponding echo signal matrix R t (k), k represents the kth frequency point in the set s, t = 1, 2, ..., T, T represents the number of radar receiver channels;

[0058] S300, for each echo signal matrix R t (k) performing low-frequency filtering and / or DC component suppression, and performing fast Fourier transform;

[0059] S400: Perform energy merging processing on all obtained fast Fourier transform sequences to obtain the radar noise floor power.

[0060] In step S100, when dividing the frequency points, the number of frequency points is determined in combination with the signal bandwidth occupied by the radar during operation and the hardware circuit characteristics of the radar transmitter and receiver. The basic principles for dividing the frequency points include at least one of the following: the smaller the bandwidth occupied by the radar during operation, the smaller the number of frequency points; the worse the consistency of the in-band gain and noise figure characteristics of the hardware circuit of the radar transmitter and receiver, the larger the number of frequency points.

[0061] For example, when the radar's operating bandwidth is relatively small (e.g., only a few thousand hertz), and the in-band gain and noise figure characteristics of the radar transmitter and receiver hardware circuits are highly consistent, a small number of frequency points can be selected within the radar's operating bandwidth to form a set s, such as selecting a single frequency point. When the radar's operating bandwidth is relatively large (e.g., above several hundred megahertz), and the circuit's in-band gain consistency and noise figure characteristics are poorly consistent, multiple frequency points can be selected at equal intervals to form a set s based on the signal bandwidth occupied by the radar during operation.

[0062] As a more specific example, assuming that the signal bandwidth occupied by the radar during operation is above 100 MHz, then:

[0063] When the radar is an SFCW radar (stepped frequency radar), the set s is equal to the set consisting of all the ready-to-transmit radio frequency points of the SFCW radar;

[0064] When the radar is an FMCW radar (frequency modulated continuous wave radar), the frequency points are selected at equal intervals based on the signal bandwidth occupied by the radar during operation. The set s is expressed as {f0+μ*h*Ts, h = 0, 1, 2, ..., H-1}. Here, f0 is the starting frequency of the FMCW radar frequency sweep, μ is the sweep slope of the FMCW radar, Ts is the ADC sampling rate of the FMCW radar receiver, and H is the total number of signal samples collected by the radar receiver ADC during a single radar signal waveform transmission when the FMCW radar is operating normally.

[0065] In step S200, the preset method is specifically as follows: for the kth frequency point in the set s, the radar performs a total of M signal transmission processes. During each transmission process, the radar transmits a single tone signal fixed at the kth frequency point, and the tth receiver channel of the radar receives and samples the echo signal to obtain N sampled output signals; M*N sampled output signals are accumulated to form the echo signal matrix R t (k); where the nth sampled output signal of the mth transmission and the tth receiver channel is R t The element in the nth row and mth column of (k), n = 1, 2, ..., N; m = 1, 2, ..., M; t = 1, 2, ..., T; T represents the number of radar receiver channels.

[0066] Among them, in order to ensure that the estimated noise floor is as consistent as possible with the noise floor during normal working of the radar and reduce unnecessary gain conversion processes, during the noise floor estimation process, the circuit operating states of the radar transmitter and receiver are consistent with those during normal working of the radar, including the duration of each radar transmission frequency point, transmission power, ADC sampling rate, circuit calibration control, clock control signal, phase-locked loop parameters, gain control parameters, analog circuit filter bandwidth, impedance and circuit leakage suppression control, chirp signal sweep time, number of radar receiver channels, etc.

[0067] In addition, when executing step S200, the radar is shut down and then turned on again between two adjacent transmission processes to reduce the coherence of various color noises and avoid the coherent accumulation of color noise components in the slow time dimension of each echo signal matrix (reducing the column correlation of the matrix), which leads to inaccurate background noise estimation.

[0068] In step S200 of this embodiment, the radar can be in a single-transmit, single-receive configuration (i.e., T = 1) or a MIMO configuration (i.e., T > 1). When the radar is in a MIMO configuration, it can operate in various virtual array configurations, such as TDM, FDM, and CDM. The virtual array configuration allows the MIMO radar to create more virtual receive channels than the actual number of receive channels of the radar receiver. This embodiment does not limit the specific operating configuration of the radar. T is not limited to referring to the actual number of receiver channels of the radar, but rather includes the virtual receive channels available to the radar in the virtual array configuration.

[0069] In step S300, the specific method of performing low-frequency filtering on each echo signal matrix includes:

[0070] Perform high-pass filtering in the fast time dimension and transform the echo signal matrix R t The elements of the mth column of (k) are fed into the filter in sequence, and the output sequence of the filter is used as the updated R t The m-th column element of (k), where m = 1, 2, ..., M; or

[0071] Perform high-pass filtering in the slow time dimension and transform the echo signal matrix R t The elements of the nth row of (k) are fed into the filter in sequence, and the output sequence of the filter is used as the updated R t (k) The element in the nth row, n = 1, 2, ..., N;

[0072] The filter transfer function is H(z) = (1 - z -1 ) / (1-ɑ*z -1 ), z represents the complex frequency domain variable of the discrete-time system, and ɑ is the preset filter coefficient.

[0073] Specifically, taking filtering in the slow time dimension as an example, the elements [r n,1 (k), r n,2 (k), r n,3 (k), ..., r n,m (k), ..., r n,M (k)] is used as the input of the filter and is sent to the high-pass filter for filtering. The corresponding filter output is recorded as [y n,1 (k), y n,2 (k), y n,3 (k), ..., y n,m (k), ..., y n,M (k)],[y n,1 (k), y n,2 (k), y n,3(k), ..., y n,m (k), ..., y n,M (k)] is the updated R t The elements of the nth row of (k) are such that when the filter transfer function is H(z) = (1 - z -1 ), the value of M can be 2, and the updated R needs to be discarded t (k) The first column of data is discarded to skip the convergence process of the filter; when a higher-order high-pass filter is used, the value of M is greater than 1 and the value of M needs to be greater than the number required for the filter to converge and stabilize, and the number of discarded columns needs to be greater than the number required for the filter to converge and stabilize. This embodiment does not impose further restrictions on the filter transfer function, the value of M, and the number of discarded columns; filtering processing in the fast time dimension is also a similar filtering update and discarding process of the first few rows to obtain a filtered echo signal matrix.

[0074] In step S300, the specific method of suppressing the DC component of each echo signal matrix includes:

[0075] In the fast time dimension, the echo signal matrix R t Each element of the mth column of (k) is subtracted from the mean of the mth column, and the output sequence is used as the updated R t (k) the mth column element; or,

[0076] In the slow time dimension, the echo signal matrix R t Each element in the nth row of (k) is subtracted from the mean of the nth row, and the output sequence is used as the updated R t (k) The element in the nth row of

[0077] It is understandable that the low-speed suppression capabilities of the low-frequency filtering processing described above are different. In this embodiment, N echo signals of the same frequency are collected during a signal waveform transmission process (fast time dimension). The method of subtracting the mean in the fast time dimension can provide a stronger low-frequency (low-speed) signal suppression capability than in the slow time dimension, so that the estimated background noise is closer to the real background noise; when it is necessary to observe and evaluate various low- and medium-frequency interference characteristics of the radar transceiver circuit, it is usually necessary to properly control the suppression capability of the low-speed filtering. Low-frequency filtering can be performed in the slow time dimension, and the low-frequency filtering capability of the slow time dimension can be changed by adjusting the transmission interval between two adjacent signal waveforms. The smaller the time interval, the stronger the suppression capability in the same slow time dimension low-speed filtering scheme.

[0078] It is understandable that in order to ensure that the estimated noise floor is consistent with the noise floor when the radar is in normal working condition and to reduce the additional gain conversion process, the low-speed filtering processing method is kept consistent with the low-frequency filtering method used when the radar is in normal working condition or the low-frequency suppression bandwidth is as close as possible.

[0079] As can be seen above, low-frequency filtering in the fast and slow time dimensions each has its own advantages and can be applied to different scenarios. Furthermore, low-frequency filtering and DC component suppression have similar functions, but their effects and applicable scenarios differ slightly. They can be used independently or in combination.

[0080] In step S300, the specific method of performing fast Fourier transform includes:

[0081] For the echo signal matrix after low-frequency filtering and / or DC component suppression, elements in the same column are selected for windowing and then a one-dimensional fast Fourier transform is performed.

[0082] Specifically, for the echo signal matrix after low-frequency filtering and / or DC component suppression, elements in the same column are selected for windowing, and then a one-dimensional fast Fourier transform is performed. The windowing method and the number of fast Fourier transform points are consistent with the windowing method and the number of fast Fourier transform points when the radar is operating normally. This ensures that the estimated noise floor is consistent with the noise floor when the radar is operating normally, and no additional gain conversion is required. In particular, when there are obvious nonlinear characteristics in the radar circuit, such as phase noise, flicker noise, nonlinear leakage interference, etc., maintaining a signal processing method or circuit operating state consistent with that when the radar is operating normally can reduce the estimation error caused by gain conversion.

[0083] like Figure 2 As shown, as a preferred implementation, the radar noise floor estimation method provided in this embodiment further includes:

[0084] S500 , averaging the energy of elements with the same Fourier transform sequence number in all obtained fast Fourier transform sequences to obtain radar range spectrum noise floor power.

[0085] like Figure 3 As shown, as a further preferred implementation, the radar noise floor estimation method provided in this embodiment further includes:

[0086] S600 : Perform gain conversion on the obtained radar range spectrum noise floor power to obtain the radar's range-velocity spectrum noise floor power, range-velocity spectrum-angle spectrum noise floor power, and / or range-angle spectrum noise floor power.

[0087] Specifically, the energy of elements with the same Fourier transform sequence (such as Fourier transform sequence w) in all the obtained Fourier transform sequences is averaged to obtain the noise floor power of the w-th range gate of the radar range spectrum, where w = 0, 1, 2, ..., W, where W represents the number of points in the range-dimensional FFT.

[0088] Next, the noise floor power of the obtained radar range spectrum is gain-converted to obtain the noise floor power of the range-velocity spectrum. If the estimated noise floor power of the w-th range gate of the range spectrum is P(w), then the noise floor power of all velocity gates corresponding to the w-th range gate of the range-velocity spectrum is P(w)*g0, where g0 is the gain conversion coefficient, which depends on the processing gain when performing the velocity-dimensional FFT. g0 is equal to the reciprocal of the mean of the sum of squares of the windowed sequence of the velocity-dimensional FFT or the reciprocal of the mean of the sum of squares of the windowed sequence of the velocity-dimensional FFT multiplied by the reciprocal of the length of the input sequence of the velocity-dimensional FFT when the radar is operating normally.

[0089] Furthermore, the noise floor power of the obtained radar range spectrum is gain-converted to obtain the noise floor power of the range-velocity spectrum-angle spectrum. If the noise floor power of the w-th range gate of the range spectrum is estimated to be P(w), then the noise floor powers of all velocity gates and angle gates corresponding to the w-th range gate of the range-velocity spectrum-angle spectrum are P(w)*g1, where g1 is the gain conversion coefficient, which depends on the processing gain when performing the velocity-dimensional FFT. g1 is equal to g0 multiplied by Q1 (Q1 is the inverse of the mean of the sum of squares of the windowed sequence of the angle-dimensional FFT) or g0 multiplied by Q2 (Q2 is the inverse of the mean of the sum of squares of the windowed sequence of the angle-dimensional FFT multiplied by the inverse of the length of the input sequence of the velocity-dimensional FFT when the radar is operating normally).

[0090] Furthermore, the noise floor power of the obtained radar range spectrum is gain-converted to obtain the noise floor power of the range-angle spectrum. If the noise floor power of the w-th range gate of the range spectrum is estimated to be P(w), then the noise floor power of all angle gates corresponding to the w-th range gate of the range-angle spectrum is P(w)*g2, where g2 is the gain conversion coefficient, which is equal to the reciprocal of the mean of the sum of squares of the windowed sequence of the angle-dimensional FFT or the reciprocal of the mean of the sum of squares of the windowed sequence of the angle-dimensional FFT multiplied by the reciprocal of the length of the input sequence of the angle-dimensional FFT when the radar is working normally.

[0091] It can be understood that this embodiment uses the preset transmission method to perform frequency transmission (transmitting a single audio frequency in the fast time dimension), concentrates the energy of the moving target interference in the environment near the zero frequency, and filters out the influence of the interference through low-frequency filtering. The sampling rate of the fast time dimension is higher, and the ability to suppress low-frequency echo signals in the fast time dimension is stronger. There is no need to filter the influence of the interference echo signal through the conventional two-dimensional FFT method. Only the one-dimensional FFT method can fully suppress the moving target interference, and estimate the noise floor power of the range spectrum or range-velocity spectrum, thereby improving the efficiency of the noise floor estimation.

[0092] The radar noise floor estimation method provided in this embodiment can also be further expanded to utilize a two-dimensional FFT approach to estimate the noise floor and obtain the noise floor power of the radar range-velocity spectrum. Specifically, a two-dimensional fast Fourier transform is performed on each echo signal matrix, and the energy of elements with the same range-dimension Fourier transform sequence is averaged to obtain the noise floor power for all velocity dimensions at the corresponding range gate in the radar range-velocity spectrum. This method requires a two-dimensional FFT transform. The method of obtaining the echo signal matrix and performing low-speed filtering or DC component filtering on the fast time dimension of the echo signal matrix in this embodiment provides a higher level of filtering of low-frequency echo interference signals than conventional swept-frequency two-dimensional FFTs.

[0093] The radar noise floor estimation method provided in this embodiment can also be further expanded to use a three-dimensional FFT method to perform noise floor estimation to obtain the noise floor power of the radar range-velocity-angle spectrum. Specifically, all the echo signal matrices obtained are arranged into a three-dimensional matrix of N*M*T and a three-dimensional FFT is performed. The energy of the elements with the same distance dimension Fourier transform sequence number is averaged to obtain the noise floor power of all speed and angle dimensions on the corresponding distance dimension in the range-velocity-angle spectrum. This method requires a three-dimensional FFT transformation, which is computationally intensive and has no advantages over other embodiments of the present application. However, the method of obtaining the echo signal matrix and filtering the echo signal matrix in the fast time dimension or the DC component in the present application has a higher ability to suppress low-speed echo interference signals than the three-dimensional FFT in the conventional frequency sweeping mode.

[0094] As a specific application of this embodiment, if the radar is working normally, a super-resolution algorithm (such as Music, MVDR, high-order cumulant, compressed sensing, sparse Bayesian learning algorithm, etc.) is used to measure target parameters. The method of this embodiment can be used to obtain the echo signal matrix after low-frequency filtering or DC component suppression, and the corresponding super-resolution algorithm is executed on each echo signal matrix. The mean of the square modulus of the super-resolution spectrum on each echo signal matrix is ​​calculated as the background noise energy of various super-resolution algorithms.

[0095] In addition, the operation process of the radar noise floor estimation method provided in the embodiment may be repeated multiple times, and the multiple noise floor power estimation results may be averaged to reduce the estimation error.

[0096] Combine Figure 4 As shown, the present invention provides a radar noise floor estimation device, including the following modules:

[0097] The frequency point set acquisition module divides several frequency points into a set s according to the signal bandwidth occupied by the radar during operation;

[0098] The echo signal matrix generation module selects each frequency point in the set s, transmits and receives the echo signal according to the preset method, and obtains the corresponding echo signal matrix;

[0099] The data processing module performs low-frequency filtering and / or DC component suppression on each echo signal matrix and performs fast Fourier transform;

[0100] The radar noise floor power acquisition module combines the energy of all the obtained fast Fourier transform sequences to obtain the radar noise floor power.

[0101] Combine Figure 5 As shown, as a preferred embodiment, the radar noise floor estimation device further includes:

[0102] The radar range spectrum noise floor power acquisition module averages the energy of elements with the same Fourier transform sequence number in all the obtained fast Fourier transform sequences to obtain the radar range spectrum noise floor power.

[0103] Combine Figure 6 As shown, as a further preferred embodiment, the radar noise floor estimation device further includes:

[0104] The gain conversion module performs gain conversion on the obtained radar range spectrum noise floor power to obtain the radar's range-velocity spectrum noise floor power, range-velocity spectrum-angle spectrum noise floor power, and / or range-angle spectrum noise floor power.

[0105] The embodiment of the present invention further provides a storage medium, which can store multiple instructions, which are suitable for the processor to load and execute the method steps of the radar noise estimation method described above. The specific execution process can be seen in Figure 2 The detailed description of the illustrated embodiment will not be repeated here.

[0106] See Figure 7 , which provides a schematic diagram of the structure of a terminal device according to an embodiment of the present invention. Figure 7 As shown, the terminal device 500 may include: at least one processor 501 , at least one network interface 504 , a user interface 503 , a memory 505 , and at least one communication bus 502 .

[0107] The communication bus 502 is used to implement the connection and communication between these components.

[0108] The user interface 503 may include a display screen (Display) and a camera (Camera). Optionally, the user interface 503 may also include a standard wired interface and a wireless interface.

[0109] The network interface 504 may optionally include a standard wired interface or a wireless interface (such as a WI-FI interface).

[0110] The processor 501 may include one or more processing cores. The processor 501 utilizes various interfaces and circuits to connect various components within the terminal device 500. It executes instructions, programs, code sets, or instruction sets stored in the memory 505, and accesses data stored in the memory 505 to perform various functions and process data within the terminal device 500. Optionally, the processor 501 may be implemented using at least one of the following hardware forms: a digital signal processing (DSP), a field-programmable gate array (FPGA), or a programmable logic array (PLA). The processor 501 may integrate one or a combination of a central processing unit (CPU), a graphics processing unit (GPU), and a modem. The CPU primarily processes the operating system, user interface, and application programs; the GPU is responsible for rendering and drawing content displayed on the display; and the modem handles wireless communications. It is understood that the modem may also be implemented as a separate chip, rather than integrated into the processor 501.

[0111] Among them, the memory 505 may include a random access memory (RAM) or a read-only memory (Read-Only Memory). Optionally, the memory 505 includes a non-transitory computer-readable storage medium. The memory 505 can be used to store instructions, programs, codes, code sets or instruction sets. The memory 505 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, a sound playback function, an image playback function, etc.), instructions for implementing the above-mentioned various method embodiments, etc.; the data storage area may store data involved in the above-mentioned various method embodiments, etc. The memory 505 may also be optionally at least one storage device located away from the aforementioned processor 501. As Figure 7 As shown, the memory 505 as a storage medium may include an operating system, a network communication module, a user interface module and an application program.

[0112] exist Figure 7 In the terminal device 500 shown, the user interface 503 is mainly used to provide an input interface for the user and obtain the data input by the user; and the processor 501 can be used to call the application stored in the memory 505 and specifically execute the radar noise estimation method described above. The specific process can be combined with Figures 1 to 3 As shown, no further details are given here.

[0113] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing related hardware through a computer program. The program can be stored in a readable storage medium, and when executed, the program can include the processes in the above-described method embodiments. The storage medium can be a magnetic disk, an optical disk, a read-only memory, or a random access memory.

[0114] The above disclosure is merely a preferred embodiment of the present invention and certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A radar noise floor estimation method, characterized in that: include: S100, dividing a number of frequency points according to the signal bandwidth occupied by the radar during operation to form a set s; S200, select each frequency point in the set s, transmit and receive echo signals according to the preset method, and obtain the corresponding echo signal matrix R t (k), k represents the kth frequency point in the set s, t = 1, 2, ..., T, T represents the number of radar receiver channels; S300, for each echo signal matrix R t (k) performing low-frequency filtering and / or DC component suppression, selecting elements in the same column of the echo signal matrix after low-frequency filtering and / or DC component suppression, performing windowing, and then performing a one-dimensional fast Fourier transform; S400: Perform energy merging processing on all obtained fast Fourier transform sequences to obtain the radar noise floor power.

2. The radar noise floor estimation method according to claim 1, characterized in that: In step S200, the preset method is specifically as follows: for the kth frequency point in the set s, the radar performs a total of M signal transmission processes. During each transmission process, the radar transmits a single tone signal fixed at the kth frequency point, and the tth receiver channel of the radar receives and samples the echo signal to obtain N sampled output signals; M*N sampled output signals are accumulated to form the echo signal matrix R t (k); where the nth sampled output signal of the mth transmission and the tth receiver channel is R t The element in the nth row and mth column of (k), n = 1, 2, ..., N; m = 1, 2, ..., M; t = 1, 2, ..., T; T represents the number of radar receiver channels.

3. The radar noise floor estimation method according to claim 2, characterized in that: When executing step S200, between two adjacent transmission processes, the radar is shut down and then turned on once.

4. The radar noise floor estimation method according to claim 1, wherein: In step S300, the specific method of performing low-frequency filtering on each echo signal matrix includes: Perform high-pass filtering in the fast time dimension and transform the echo signal matrix R t The elements of the mth column of (k) are fed into the filter in sequence, and the output sequence of the filter is used as the updated R t (k) the mth column element; or, Perform high-pass filtering in the slow time dimension and transform the echo signal matrix R t The elements of the nth row of (k) are fed into the filter in sequence, and the output sequence of the filter is used as the updated R t (k) The element in row n; The filter transfer function is H(z) = (1 - z -1 ) / (1-ɑ*z -1 ), z represents the complex frequency domain variable of the discrete-time system, and ɑ is the preset filter coefficient.

5. The radar noise floor estimation method according to claim 1, wherein: In step S300, the specific method of suppressing the DC component of each echo signal matrix includes: In the fast time dimension, the echo signal matrix R t Each element of the mth column of (k) is subtracted from the mean of the mth column, and the output sequence is used as the updated R t (k) the mth column element; or, In the slow time dimension, the echo signal matrix R t Each element in the nth row of (k) is subtracted from the mean of the nth row, and the output sequence is used as the updated R t (k) The element in the nth row.

6. The radar noise floor estimation method according to claim 1, characterized in that: The radar noise floor estimation method further includes: S500 , averaging the energy of elements with the same Fourier transform sequence number in all obtained one-dimensional fast Fourier transform sequences to obtain radar range spectrum noise floor power.

7. The radar noise floor estimation method according to claim 6, characterized in that: The radar noise floor estimation method further includes: S600 : Perform gain conversion on the obtained radar range spectrum noise floor power to obtain the radar's range-velocity spectrum noise floor power, range-velocity spectrum-angle spectrum noise floor power, and / or range-angle spectrum noise floor power.

8. A radar noise floor estimation device, characterized in that: include: The frequency point set acquisition module divides several frequency points into a set s according to the signal bandwidth occupied by the radar during operation; The echo signal matrix generation module selects each frequency point in the set s, transmits and receives the echo signal according to the preset method, and obtains the corresponding echo signal matrix R t (k); A data processing module performs low-frequency filtering and / or DC component suppression on each echo signal matrix, selects elements in the same column of the echo signal matrix after low-frequency filtering and / or DC component suppression, performs windowing, and then performs a one-dimensional fast Fourier transform; The radar noise floor power acquisition module combines the energy of all the obtained fast Fourier transform sequences to obtain the radar noise floor power.

9. A storage medium, characterized in that: The storage medium stores a plurality of instructions, which are suitable for being loaded by a processor and executing the method steps of the radar noise floor estimation method according to any one of claims 1 to 7.

10. A terminal device, characterized in that: include: A processor and a memory; wherein the memory stores a computer program, and the computer program is suitable for being loaded by the processor and executing the method steps of the radar noise floor estimation method according to any one of claims 1 to 7.

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