阅读说明：本技术 一种基于fda-mimo雷达的速度解模糊方法 (FDA-MIMO radar-based speed ambiguity resolution method ) 是由 万伟涛 张顺生 王文钦 于 2021-09-13 设计创作，主要内容包括：本发明公开了一种基于FDA-MIMO雷达的速度解模糊方法,通过构建FDA-MIMO雷达的发射端阵列与接收端阵列；通过预设频率增量计算FDA-MIMO雷达发射端阵列的阵元发射信号,并通过阵元发射信号计算接收端阵列的目标回波信号,并得到目标所在距离门的信号数据；根据信号数据分别计算存在多普勒模糊的各载频对应的估计速度与无多普勒模糊的估计速度,并利用一维集法得到目标速度估计值；本发明在不发射多个不同脉冲重复周期的信号的前提下,实现高速运动目标的无模糊速度估计,具有计算量小,获取速度精度高的优点,简化FDA-MIMO雷达的系统复杂度,提高测量速度范围,有效解决了低重频下运动目标速度出现多普勒模糊的问题。(The invention discloses a speed ambiguity-resolving method based on an FDA-MIMO radar, which comprises the steps of constructing a transmitting end array and a receiving end array of the FDA-MIMO radar; calculating array element transmitting signals of an FDA-MIMO radar transmitting end array through a preset frequency increment, calculating target echo signals of a receiving end array through the array element transmitting signals, and obtaining signal data of a range gate where a target is located; respectively calculating the estimated speed corresponding to each carrier frequency with Doppler ambiguity and the estimated speed without Doppler ambiguity according to the signal data, and obtaining a target speed estimated value by using a one-dimensional set method; the invention realizes the unambiguous velocity estimation of the high-speed moving target on the premise of not transmitting a plurality of signals with different pulse repetition periods, has the advantages of small calculated amount and high speed acquisition precision, simplifies the system complexity of the FDA-MIMO radar, improves the measuring speed range and effectively solves the problem of Doppler ambiguity of the speed of the moving target under low repetition frequency.)

1. A method for resolving ambiguity of speed based on FDA-MIMO radar is characterized by comprising the following steps:

s1, constructing a transmitting end array and a receiving end array of the FDA-MIMO radar;

s2, calculating array element transmitting signals of the transmitting end array in the step S1 according to preset frequency increment;

s3, obtaining a target echo signal of the receiving end array according to the array element transmitting signal in the step S2, and obtaining signal data of a range gate where a target is located;

s4, calculating the estimated speed corresponding to each carrier frequency with Doppler ambiguity according to the signal data in the step S3;

s5, calculating the estimated speed without Doppler ambiguity according to the signal data in the step S3;

and S6, obtaining the target speed estimated value by using a one-dimensional set method according to the estimated speed corresponding to each carrier frequency with Doppler ambiguity in the step S4 and the estimated speed without Doppler ambiguity in the step S5.

2. The FDA-MIMO radar-based speed deblurring method according to claim 1, wherein the step S1 specifically comprises:

array element numbers in a transmitting end and a receiving end of the FDA-MIMO radar are preset, and array element spacing between a transmitting array element and a receiving array element is set according to the center frequency of a transmitting signal, wherein the calculation formula of the array element spacing is as follows:

wherein d is_TTo transmit array element spacing, d_RIn order to receive the spacing between the array elements,f₀c is the speed of light for the center frequency of the transmitted signal.

3. The FDA-MIMO radar-based speed deblurring method according to claim 2, wherein the step S2 comprises the following sub-steps:

s21, calculating the array element carrier frequency of the transmitting terminal array in the step S1 according to the preset frequency increment, wherein the calculation formula is as follows:

f_m＝f₀+mΔf

wherein f is_mThe carrier frequency of the mth array element in the transmitting terminal array is delta f, and the delta f is frequency deviation;

s22, calculating the array element transmitting signal of the transmitting end according to the array element carrier frequency in the step S21, wherein the calculation formula is as follows:

wherein s is_m(t) is the transmission signal of the m-th array element at the transmitting end, phi_mAnd (t) is a baseband signal transmitted by the mth array element of the transmitting end, j is an imaginary number, e and pi are constants, and t is a time variable.

4. The FDA-MIMO radar-based speed deblurring method according to claim 3, wherein the step S3 comprises the following sub-steps:

s31, calculating the target echo signal received by the receiving end array according to the array element transmitting signal in the step S2, wherein the target echo signal is expressed as:

wherein, y_k(. h) is a target echo signal of the kth pulse received by the receiving end array, theta is a target azimuth angle, r is a distance between the target and the receiving end, v is a target speed, (. h)^TFor transposition, xi is the complex reflection characteristic parameter of the target, T_prIs the pulse repetition period of the pulse train in the transmitted signal, N (t) is the Gaussian white noise of the receiving array elements in each receiving end array, a_T(. is a steering vector of the transmitting-end array, a_R(. is the steering vector, Ω, of the receiving end array_D(. cndot.) is a Doppler shift matrix of the FDA-MIMO radar, e (-) is a carrier vector of the FDA-MIMO radar, s_m(. is the transmission signal of the M-th array element of the transmitting end, M_TThe total number of the transmitting array elements is;

s32, performing multi-channel mixing and matched filtering on the target echo signal in the step S31 to obtain an echo signal subjected to matched filtering;

s33, processing the echo signal after matched filtering in the step S32 by adopting an FDA-MIMO radar signal processing method to obtain signal data of a range gate where the target is located, wherein the signal data is represented as:

wherein, Y_kSignal data of the range gate in which the object is located, a_T(. is a distance-angle joint steering vector, M_RIs the total number of the receiving array elements.

5. The FDA-MIMO radar-based speed deblurring method according to claim 4, wherein the step S4 comprises the following sub-steps:

s41, extracting each column of data of the signal data in the step S3, and constructing a data matrix;

s42, calculating a covariance matrix according to the data matrix in the step S41, wherein the covariance matrix is expressed as:

wherein R is_mIs a covariance matrix, K is the total number of pulses of the transmitted signal, Z_mIs a data matrix corresponding to the m-th array element carrier frequency, (. DEG)^HIs a conjugate transpose;

s43, calculating the Doppler frequency corresponding to each carrier frequency according to the data matrix in the step S41 and the covariance matrix in the step S42, and showing as:

wherein the content of the first and second substances,the carrier frequency of the mth array element is the corresponding Doppler frequency,to take the Doppler frequency f corresponding to the maximum value of the function_d，ω(f_d) For all possible Doppler frequency vectors, (. C)^*Is conjugation;

s44, calculating the estimated velocity corresponding to each carrier frequency having doppler ambiguity according to the doppler frequency in step S43, which is expressed as:

wherein v is_mAnd the estimated speed corresponding to the m-th array element carrier frequency.

6. The FDA-MIMO radar-based speed deblurring method according to claim 5, wherein the step S41 specifically comprises:

and (5) extracting data of each line of the signal data in the step (S3) to obtain a data vector corresponding to each carrier frequency, and constructing a data matrix corresponding to each carrier frequency after all pulse data are obtained.

7. The FDA-MIMO radar-based speed deblurring method according to claim 5, wherein the step S5 comprises the following sub-steps:

s51, calculating the initial estimated velocity without Doppler ambiguity according to the signal data in the step S3, and showing that:

wherein x is_kThe initial estimated velocity without doppler ambiguity is: the phase difference between the echo data of the respective carrier frequencies,signal data Y of the range gate where the target is located in step S32_kMatrix element y of_j,i,kConjugation, y_j,i+1,kSignal data Y of the range gate where the target is located in step S32_kA matrix element of (a);

s52, performing fast Fourier transform on the initial estimated speed in the step S51, and selecting the frequency corresponding to the maximum value of the transformed frequency spectrum to calculate the estimated speed without Doppler ambiguity, wherein the estimated speed is represented as:

wherein v is_xFFT (x) for Doppler ambiguity free estimation of velocity_k) For the initial estimated speed x_kAnd performing fast Fourier transform.

8. The FDA-MIMO radar-based speed deblurring method according to claim 7, wherein the step S6 comprises the following sub-steps:

s61, calculating fuzzy parameters according to the estimated speed corresponding to each carrier frequency with Doppler fuzzy in the step S4 and the estimated speed without Doppler fuzzy in the step S5, and determining a search range;

s62, sorting the target speed values in the search range according to the search range determined in the step S61, and calculating the mean value and the variance in groups;

s63, selecting the mean value corresponding to the minimum value in each group of variances in the step S62 as the target speed estimation value by using a one-dimensional set method root.

9. The FDA-MIMO radar-based speed deblurring method according to claim 8, wherein the fuzzy parameter calculation formula in step S61 is expressed as:

wherein the content of the first and second substances,for fuzzy parameters [ ·]In order to be a function of the rounding,the maximum velocity of the unambiguous estimation corresponding to the m-th array element carrier frequency.

10. The FDA-MIMO radar-based velocity deblurring method according to claim 8, wherein the variance is calculated in step S62 as:

wherein, C_v(j) Is the variance of the jth data set,is the m-th data group of the j^*Individual velocity value, V_jFor M in the search range_TThe j-th data group constructed by the continuous velocity values,is the average of the j-th data set.

Technical Field

The invention relates to the technical field of radar signal processing, in particular to a speed ambiguity resolving method based on an FDA-MIMO radar.

Background

The concept of Frequency diversity Array (abbreviated as FDA) was first proposed by Antonik and Wicks, and this Array mainly realizes new system functions by adjusting the carrier Frequency difference between the Array elements. The multi-carrier frequency signals transmitted by the frequency diversity array bring new advantages to the detection and parameter estimation of the target.

The Multiple-Input Multiple-Output (MIMO) technology can make full use of the advantage of the frequency diversity array to transmit Multiple carrier frequency signals, so that the transmit steering vectors can be well separated at the receiving end. Therefore, two technologies are often combined to form the radar of the FDA-MIMO system.

For conventional pulse doppler radar, a target moving at high speed tends to cause velocity ambiguity due to the limitation of the netript sampling frequency. To solve this problem, the velocity of the moving object can be estimated by using a plurality of signal pulses with different pulse repetition periods, and the range of the measurement velocity can be increased. But this increases the complexity of the radar system. For the FDA-MIMO system radar, the system complexity of the system radar is obviously greatly increased.

Disclosure of Invention

To the above in the prior art: the invention provides a method for resolving the speed ambiguity based on an FDA-MIMO radar.

In order to achieve the purpose of the invention, the invention adopts the technical scheme that:

a method for resolving ambiguity of speed based on FDA-MIMO radar comprises the following steps:

s1, constructing a transmitting end array and a receiving end array of the FDA-MIMO radar;

s2, calculating array element transmitting signals of the transmitting end array in the step S1 according to preset frequency increment;

s3, obtaining a target echo signal of the receiving end array according to the array element transmitting signal in the step S2, and obtaining signal data of a range gate where a target is located;

s4, calculating the estimated speed corresponding to each carrier frequency with Doppler ambiguity according to the signal data in the step S3;

s5, calculating the estimated speed without Doppler ambiguity according to the signal data in the step S3;

and S6, obtaining the target speed estimated value by using a one-dimensional set method according to the estimated speed corresponding to each carrier frequency with Doppler ambiguity in the step S4 and the estimated speed without Doppler ambiguity in the step S5.

The invention has the following beneficial effects:

the method comprises the steps of constructing a transmitting end array and a receiving end array of the FDA-MIMO radar, calculating an array element transmitting signal of the transmitting end array through a preset frequency increment, calculating a target echo signal of the receiving end array according to the obtained array element transmitting signal of the transmitting end array, obtaining signal data of a range gate where a target is located, calculating an estimated speed corresponding to each carrier frequency with Doppler ambiguity and an estimated speed without Doppler ambiguity by utilizing the signal data respectively, obtaining a target speed estimated value by combining a one-dimensional set method, realizing the unambiguous speed estimation of a high-speed moving target on the premise of not transmitting signals of a plurality of different pulse repetition periods, having the advantages of small calculated amount, high speed accuracy and the like, and effectively solving the problem of Doppler ambiguity of the moving target speed under low repetition frequency.

Further, step S1 is specifically:

array element numbers in a transmitting end and a receiving end of the FDA-MIMO radar are preset, and array element spacing between a transmitting array element and a receiving array element is set according to the center frequency of a transmitting signal, wherein the calculation formula of the array element spacing is as follows:

wherein d is_TTo transmit array element spacing, d_RIn order to receive the spacing between the array elements,f₀c is the speed of light for the center frequency of the transmitted signal.

Further, step S2 specifically includes the following sub-steps:

s21, calculating the array element carrier frequency of the transmitting terminal array in the step S1 according to the preset frequency increment, wherein the calculation formula is as follows:

f_m＝f₀+mΔf

wherein f is_mThe carrier frequency of the mth array element in the transmitting terminal array is delta f, and the delta f is frequency deviation;

s22, calculating the array element transmitting signal of the transmitting end according to the array element carrier frequency in the step S21, wherein the calculation formula is as follows:

wherein s is_m(t) is the transmission signal of the m-th array element at the transmitting end, phi_mAnd (t) is a baseband signal transmitted by the mth array element of the transmitting end, j is an imaginary number, e and pi are constants, and t is a time variable.

Further, S31, calculating a target echo signal received by the receiving end array according to the array element transmitting signal in step S2, which is represented as:

wherein, y_k(. h) is a target echo signal of the kth pulse received by the receiving end array, theta is a target azimuth angle, r is a distance between the target and the receiving end, v is a target speed, (. h)^TFor transposition, xi is the complex reflection characteristic parameter of the target, T_prIs the pulse repetition period of the pulse train in the transmitted signal, N (t) is the Gaussian white noise of the receiving array elements in each receiving end array, a_T(. is a steering vector of the transmitting-end array, a_R(. is the steering vector, Ω, of the receiving end array_D(. cndot.) is a Doppler shift matrix of the FDA-MIMO radar, e (-) is a carrier vector of the FDA-MIMO radar, s_m(. is the transmission signal of the M-th array element of the transmitting end, M_TThe total number of the transmitting array elements is;

s32, performing multi-channel mixing and matched filtering on the target echo signal in the step S31 to obtain an echo signal subjected to matched filtering;

s33, processing the echo signal after matched filtering in the step S32 by adopting an FDA-MIMO radar signal processing method to obtain signal data of a range gate where the target is located, wherein the signal data is represented as:

wherein, Y_kSignal data of the range gate in which the object is located, a_T(. is a distance-angle joint steering vector, M_RIs the total number of the receiving array elements.

Further, step S4 specifically includes the following sub-steps:

step S4 specifically includes the following substeps:

s41, extracting each column of data of the signal data in the step S3, and constructing a data matrix;

s42, calculating a covariance matrix according to the data matrix in the step S41, wherein the covariance matrix is expressed as:

wherein R is_mIs a covariance matrix, K is the total number of pulses of the transmitted signal, Z_mIs a data matrix corresponding to the m-th array element carrier frequency, (. DEG)^HIs a conjugate transpose;

s43, calculating the Doppler frequency corresponding to each carrier frequency according to the data matrix in the step S41 and the covariance matrix in the step S42, and showing as:

wherein the content of the first and second substances,the carrier frequency of the mth array element is the corresponding Doppler frequency,to take the Doppler frequency f corresponding to the maximum value of the function_d，ω(f_d) For all possible Doppler frequency vectors, (. C)^*Is conjugation;

s44, calculating the estimated velocity corresponding to each carrier frequency having doppler ambiguity according to the doppler frequency in step S43, which is expressed as:

wherein v is_mAnd the estimated speed corresponding to the m-th array element carrier frequency.

Further, step S41 is specifically:

and (5) extracting data of each line of the signal data in the step (S3) to obtain a data vector corresponding to each carrier frequency, and constructing a data matrix corresponding to each carrier frequency after all pulse data are obtained.

Further, step S5 specifically includes the following sub-steps:

step S5 specifically includes the following substeps:

s51, calculating the initial estimated velocity without Doppler ambiguity according to the signal data in the step S3, and showing that:

wherein x is_kThe initial estimated velocity without doppler ambiguity is: the phase difference between the echo data of the respective carrier frequencies,signal data Y of the range gate where the target is located in step S32_kMatrix element y of_j,i,kConjugation, y_j,i+1,kSignal data Y of the range gate where the target is located in step S32_kA matrix element of (a);

s52, performing fast Fourier transform on the initial estimated speed in the step S51, and selecting the frequency corresponding to the maximum value of the transformed frequency spectrum to calculate the estimated speed without Doppler ambiguity, wherein the estimated speed is represented as:

wherein v is_xFFT (x) for Doppler ambiguity free estimation of velocity_k) For the initial estimated speed x_kAnd performing fast Fourier transform.

Further, step S6 specifically includes the following sub-steps:

s61, calculating fuzzy parameters according to the estimated speed corresponding to each carrier frequency with Doppler fuzzy in the step S4 and the estimated speed without Doppler fuzzy in the step S5, and determining a search range;

s62, sorting the target speed values in the search range according to the search range determined in the step S61, and calculating the mean value and the variance in groups;

s63, selecting the mean value corresponding to the minimum value in each group of variances in the step S62 as the target speed estimation value by using a one-dimensional set method root.

Further, the fuzzy parameter calculation formula in step S61 is expressed as:

wherein the content of the first and second substances,for fuzzy parameters [ ·]In order to be a function of the rounding,the maximum velocity of the unambiguous estimation corresponding to the m-th array element carrier frequency.

Further, the calculation formula of the variance in step S62 is expressed as:

wherein, C_v(j) Is the variance of the jth data set,is the m-th data group of the j^*Individual velocity value, V_jFor M in the search range_TThe j-th data group constructed by the continuous velocity values,is the average of the j-th data set.

The further scheme has the following beneficial effects:

1. the signal-to-noise ratio is improved by carrying out multichannel frequency mixing and matched filtering on the target echo signal, so that the subsequent processing is facilitated;

2. the estimation precision of the speed is further improved by a one-dimensional set method.

Drawings

FIG. 1 is a flow chart illustrating the steps of a FDA-MIMO radar-based speed deblurring method according to the present invention;

fig. 2 is a schematic structural diagram of an FDA-MIMO radar according to an embodiment of the present invention;

FIG. 3 is a flowchart illustrating the substeps of step S2 according to the present invention;

FIG. 4 is a flowchart illustrating steps in step S3 according to the present invention;

fig. 5 is a schematic structural diagram of an FDA-MIMO radar receiver according to an embodiment of the present invention;

FIG. 6 is a flowchart illustrating steps in step S4 according to the present invention;

FIG. 7 is a flowchart illustrating steps in step S5 according to the present invention;

FIG. 8 is a flowchart illustrating steps in step S6 according to the present invention;

FIG. 9 is a graph of the variation of the RMSE with the SNR for the velocity estimation of different velocity targets according to the method provided in simulation experiment 1 in the embodiment of the present invention;

FIG. 10 is a diagram illustrating velocity estimates P of different velocity targets according to the method provided by simulation experiment 1 in the embodiment of the present invention_successA variation curve along with a signal-to-noise ratio;

FIG. 11 is a graph of the variation of the estimated RMSE with the number of pulses for the speed of different speed targets according to the method provided in simulation experiment 2 in the embodiment of the present invention;

FIG. 12 is a diagram illustrating velocity estimates P of different velocity targets according to the method provided by simulation experiment 2 in the embodiment of the present invention_successCurve with pulse number.

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims, and all matters produced by the invention using the inventive concept are protected.

As shown in fig. 1, an embodiment of the present invention provides a method for resolving ambiguity of speed based on FDA-MIMO radar, including the following steps S1 to S6:

s1, constructing a transmitting end array and a receiving end array of the FDA-MIMO radar;

in this embodiment, step S1 specifically includes:

array element numbers in a transmitting end and a receiving end of the FDA-MIMO radar are preset, and array element spacing between a transmitting array element and a receiving array element is set according to the center frequency of a transmitting signal, wherein the calculation formula of the array element spacing is as follows:

wherein d is_TTo transmit array element spacing, d_RIn order to receive the spacing between the array elements,f₀c is the speed of light for the center frequency of the transmitted signal.

In practice, the FDA-MIMO radar structure is obtained by constructing a transmitting end array and a receiving end array of the FDA-MIMO radar, as shown in fig. 2.

S2, calculating array element transmitting signals of the transmitting end array in the step S1 according to preset frequency increment;

as shown in fig. 3, in the embodiment of the present invention, step S2 specifically includes the following sub-steps:

s21, calculating the array element carrier frequency of the transmitting terminal array in the step S1 according to the preset frequency increment, wherein the calculation formula is as follows:

f_m＝f₀+mΔf

wherein f is_mThe carrier frequency of the mth array element in the transmitting terminal array is delta f, and the delta f is frequency deviation;

in practice, it can also be expressed as: f. of_m＝(m-1)f₀。

S22, calculating the array element transmitting signal of the transmitting end according to the array element carrier frequency in the step S21, wherein the calculation formula is as follows:

wherein s is_m(t) is the transmission signal of the m-th array element at the transmitting end, phi_mAnd (t) is a baseband signal transmitted by the mth array element of the transmitting end, j is an imaginary number, e and pi are constants, and t is a time variable.

In practice, the transmitting signal of each transmitting end array element is a pulse train signal, and the repetition period of the pulse is T_pr。

S3, obtaining a target echo signal of the receiving end array according to the array element transmitting signal in the step S2, and obtaining signal data of a range gate where a target is located;

as shown in fig. 4, in the embodiment of the present invention, step S3 specifically includes the following sub-steps:

step S3 specifically includes the following substeps:

s31, calculating the target echo signal received by the receiving end array according to the array element transmitting signal in the step S2, wherein the target echo signal is expressed as:

wherein, y_k(. cndot.) is a target echo signal of the kth pulse received by the receiving end array, theta is a target azimuth angle, r is a distance between the target and the receiving end, v is a target velocity,(·)^Tfor transposition, xi is the complex reflection characteristic parameter of the target, T_prIs the pulse repetition period of the pulse train in the transmitted signal, N (t) is the Gaussian white noise of the receiving array elements in each receiving end array, a_T(. is a steering vector of the transmitting-end array, a_R(. is the steering vector, Ω, of the receiving end array_D(. cndot.) is a Doppler shift matrix of the FDA-MIMO radar, e (-) is a carrier vector of the FDA-MIMO radar, s_m(. is the transmission signal of the M-th array element of the transmitting end, M_TThe total number of the transmitting array elements is;

in practice, for a target with an azimuth angle theta and a distance r, a target echo signal received by a receiving end array is obtained by calculating a target approaching the radar at a constant radial speed vWherein the content of the first and second substances,for receiving end Mth_R-1 target echo signal of the kth pulse received by an array element;

wherein the steering vector of the transmitting end arrayM_TThe calculation formula is expressed as follows:

steering vector of receiving end arrayM_RFor the total number of the receiving array elements, the calculation formula is as follows:

doppler shift matrix for FDA-MIMO radarIs represented by a calculation formulaComprises the following steps:diag {. is a diagonal matrix;

carrier vector for FDA-MIMO radarThe calculation formula is shown as:

s32, performing multi-channel mixing and matched filtering on the target echo signal in the step S31 to obtain an echo signal subjected to matched filtering;

in practice, the process of performing multi-channel mixing and matched filtering on the target echo signal to obtain a matched filtered echo signal may be represented as:

wherein, y'_n,m,k(t) is the echo signal y after the frequency mixing and matched filtering of the kth target echo signal received by the nth receiving array element of the receiving end and the carrier frequency of the mth transmitting array element_n,k(t) is the kth target echo signal received by the nth receiving array element of the receiving end, phi_m' (t) is a baseband signal phi at the transmitting end_m(t) the matched impulse response function,representing a convolution operation.

S33, processing the echo signal after matched filtering in the step S32 by adopting an FDA-MIMO radar signal processing method to obtain signal data of a range gate where the target is located, wherein the signal data is represented as:

wherein, Y_kSignal data of the range gate in which the object is located, a_TIs a distance-angle combinationGuide vector, M_RIs the total number of the receiving array elements.

In practice, the echo signal received by the receiving end is subjected to multi-channel mixing and matched filtering, wherein the structure of the receiver, as shown in fig. 5, after the echo signal is subjected to the filtering processing, each pulse is sampled, and then the signal data Y of the range gate where the target is located can be obtained_kWherein the distance-angle joint steering vector a_T(r, θ), defined as:as a hadamard product.

S4, calculating the estimated speed corresponding to each carrier frequency with Doppler ambiguity according to the signal data in the step S3;

as shown in fig. 6, in the embodiment of the present invention, step S4 specifically includes the following sub-steps:

s41, extracting each column of data of the signal data in the step S3, and constructing a data matrix;

in this embodiment, step S41 specifically includes:

and (5) extracting data of each line of the signal data in the step (S3) to obtain a data vector corresponding to each carrier frequency, and constructing a data matrix corresponding to each carrier frequency after all pulse data are obtained.

In practice, the signal data Y of the range gate where the target of all K pulses is located is based on_kObtaining estimated velocities v of different carrier frequencies_mHowever, the estimated velocity is doppler ambiguity, so the estimated velocity corresponding to each carrier frequency under doppler ambiguity interference can be calculated, and the signal data Y of the range gate where the target is located needs to be calculated_kEach column in the data stream is extracted as the data quality corresponding to the mth carrier frequency, and is expressed as:

after K pulse data are processed, the data matrix Z corresponding to the mth carrier frequency can be obtained_m＝[z_m,0 z_m,1… z_m,K-1]。

S42, calculating a covariance matrix according to the data matrix in the step S41, wherein the covariance matrix is expressed as:

wherein R is_mIs a covariance matrix, K is the total number of pulses of the transmitted signal, Z_mIs a data matrix corresponding to the m-th array element carrier frequency, (. DEG)^HIs a conjugate transpose;

s43, calculating the Doppler frequency corresponding to each carrier frequency according to the data matrix in the step S41 and the covariance matrix in the step S42, and showing as:

wherein the content of the first and second substances,the carrier frequency of the mth array element is the corresponding Doppler frequency,to take the Doppler frequency f corresponding to the maximum value of the function_d，ω(f_d) For all possible doppler frequency vectors, it can be expressed as:(·)^*is conjugation;

in practice, the doppler frequency corresponding to the carrier frequency can be obtained by searching the doppler frequency.

S44, calculating the estimated velocity corresponding to each carrier frequency having doppler ambiguity according to the doppler frequency in step S43, which is expressed as:

wherein v is_mAnd the estimated speed corresponding to the m-th array element carrier frequency.

S5, calculating the estimated speed without Doppler ambiguity according to the signal data in the step S3;

in practice, the signal data Y of the range gate where the target of all K pulses is located is based on_kObtaining a velocity v without Doppler ambiguity_xV at this time_xAlthough there is no doppler ambiguity, the influence of noise is not accurate enough, and the error from the true value is large, so that the next processing is needed.

As shown in fig. 7, in this embodiment, step S5 specifically includes the following sub-steps:

s51, calculating the initial estimated velocity without Doppler ambiguity according to the signal data in the step S3, and showing that:

wherein x is_kThe initial estimated velocity without doppler ambiguity is: the phase difference between the echo data of the respective carrier frequencies,signal data Y of the range gate where the target is located in step S32_kMatrix element y of_j,i,kConjugation, y_j,i+1,kSignal data Y of the range gate where the target is located in step S32_kA matrix element of (a);

s52, performing fast Fourier transform on the initial estimated speed in the step S51, and selecting the frequency corresponding to the maximum value of the transformed frequency spectrum to calculate the estimated speed without Doppler ambiguity, wherein the estimated speed is represented as:

wherein v is_xFFT (x) for Doppler ambiguity free estimation of velocity_k) For the initial estimationSpeed x of the meter_kAnd performing fast Fourier transform.

In practice, the velocity x is initially estimated_kFFT (fast Fourier transform) is carried out, and then the frequency f corresponding to the maximum value of the frequency spectrum is found_dxThe calculation formula is as follows:the frequency f corresponding to the maximum of the frequency spectrum is obtained by combination_dxThe estimated velocity corresponding to each carrier frequency without doppler ambiguity is calculated as:

and S6, obtaining the target speed estimated value by using a one-dimensional set method according to the estimated speed corresponding to each carrier frequency with Doppler ambiguity in the step S4 and the estimated speed without Doppler ambiguity in the step S5.

As shown in fig. 8, in this embodiment, step S6 specifically includes the following sub-steps:

s61, calculating fuzzy parameters according to the estimated speed corresponding to each carrier frequency with Doppler fuzzy in the step S4 and the estimated speed without Doppler fuzzy in the step S5, and determining a search range;

in this embodiment, the fuzzy estimation parameter calculation formula in step S61 is expressed as:

wherein the content of the first and second substances,for fuzzy estimation of parameters [. C]In order to be a function of the rounding,for the maximum velocity without fuzzy estimation corresponding to the mth array element carrier frequency, the calculation formula is expressed as follows:

s62, sorting the target speed values in the search range according to the search range determined in the step S61, and calculating the mean value and the variance in groups;

in this embodiment, the calculation formula of the variance in step S62 is represented as:

wherein, C_v(j) Is the variance of the jth data set,is the m-th data group of the j^*Individual velocity value, V_jFor M in the search range_TThe j-th data group constructed by the continuous velocity values,is the average of the j-th data set.

In practice, since the existence of noise may cause an error in the estimation of the ambiguity number, it is necessary to search near the ambiguity number to obtain an accurate doppler-free ambiguity speed, and the possible speed of the estimated target for the m-th array element carrier frequency can be represented as:wherein L is the expected search range inSearching in the range, wherein l is the fuzzy number predicted by single search, all the possible speeds of the targets obtained by searching are arranged into a group, and M can be obtained_TGroup data, and M_TData in the group data are arranged from small to large, and then are sequentially arranged by M_TOne set of successive velocity values, resulting in a total of 2LM_TAnd group +1, mean and variance calculations were performed according to the above equations, respectively.

S63, selecting the mean value corresponding to the minimum value in each group of variances in the step S62 as the target speed estimation value by using a one-dimensional set method root.

In practice, according to the one-dimensional set method, by comparison C_v(j) The value is selected, and the variance C is selected_v(j) The data set having the smallest number is used as the data set having the best estimation value of the target speed, and the average value of the data sets is used as the estimation value of the target speed

In the embodiment of the present invention, the following simulation experiments are further illustrated, in which simulation parameters shown in table 1 are preset, the distance between array elements of the transmitting and receiving arrays is preset to be one half wavelength, additive white gaussian noise is added, and it is assumed that a transmitting end transmitting signal is a chirp signal, where a signal model is expressed as:

wherein the content of the first and second substances,for a pulse width of T_pRectangular pulse of (2), B_pIs the bandwidth of the baseband signal.

TABLE 1 simulation parameters

The average Root Mean Square Error (RMSE) of velocity is used to measure the accuracy of the optimal target doppler-free fuzzy velocity acquisition method. In addition, in order to measure the success rate of the optimal target doppler-blur-free acquisition method in solving the doppler blur, the embodiment of the present invention assumes that the estimation is correct when the error between the estimated velocity and the true velocity is less than 1% of the true velocity; the percentage of successful trials, P, in the multiple trials was then calculated_success。

In simulation experiment 1, the target motion speeds are respectively defined as 28.3m/s, 275.7m/s and 5675.3m/s, which respectively represent automobile and airplaneThe moving speed of the aircraft and the high-speed moving aircraft is the pulse number K of 64, the rest simulation parameters are shown in table 1, and the experimental results are shown in fig. 9 and fig. 10. However, the method in the patent can correctly estimate the speed of the target, and it can be seen from the figure that the method can obtain better estimation results for targets with different speeds, and in addition, the estimation accuracy of the target speed tends to be consistent with the increase of the signal-to-noise ratio. When the signal-to-noise ratio exceeds-26 dB, the mean Root Mean Square Error (RMSE) is less than 0.01m/s, and P_success100% will be reached.

In simulation experiment 2, the signal-to-noise ratio was fixed at-26 dB, the pulse number was varied from 8 to 128, the rest of the simulation parameters are shown in table 1, and the simulation experiment results are shown in fig. 11 and 12, where fig. 11 shows the relationship between the mean square root error RMSE and the pulse number, and fig. 12 shows P_successIn relation to the number of pulses, it can be seen that when the number of pulses exceeds 64, the mean root mean square error RMSE of the speed is below 0.01m/s and P_successIs 1. This shows that the acquisition method provided by the patent has better estimation accuracy under the condition of limited pulse number.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The principle and the implementation mode of the invention are explained by applying specific embodiments in the invention, and the description of the embodiments is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

It will be appreciated by those of ordinary skill in the art that the embodiments described herein are intended to assist the reader in understanding the principles of the invention and are to be construed as being without limitation to such specifically recited embodiments and examples. Those skilled in the art can make various other specific changes and combinations based on the teachings of the present invention without departing from the spirit of the invention, and these changes and combinations are within the scope of the invention.