A high-speed target adaptive detection method based on doppler spread effect of FDA-MIMO radar

Abstract

This invention discloses an adaptive high-speed target detection method based on the Doppler spread effect of FDA-MIMO radar, belonging to the field of radar signal processing technology. Based on a proposed target echo model using the Doppler spread effect, this invention corrects the shortcomings of simplified Doppler frequency processing in traditional models, clearly defining the quantitative correlation between target velocity, frequency offset, and other parameters and the Doppler spread effect. This provides accurate echo characterization for high-speed or high-frequency-offset scenarios, avoiding performance degradation caused by target echo model distortion. Simultaneously, by inverting the true target velocity through multi-channel Doppler frequency differences and adaptively adjusting the detection threshold, the false alarm rate of high-speed targets is significantly reduced, thereby improving the reliability of target detection.

Description

Technical Field

[0001] This invention relates to the field of radar signal processing technology, and in particular to a high-speed target adaptive detection method based on the FDA-MIMO radar Doppler spread effect. Background Technology

[0002] Frequency-Controlled Array-Multiple-Input Multiple-Output (FDA-MIMO) radar is a novel radar system that integrates frequency-controlled array (FDA) and multiple-input multiple-output (MIMO) technologies. Its key technology lies in configuring a small frequency offset for each transmission channel, which gives the FDA beam pattern a unique three-dimensional coupling characteristic of time, range, and angle. Further incorporating MIMO technology effectively decouples the correlation between range and angle dimensions, thereby significantly improving target localization accuracy. Therefore, FDA-MIMO radar demonstrates significant application potential in target detection, joint range-angle estimation, main lobe interference suppression, and range ambiguity clutter suppression.

[0003] The Doppler spread (DS) effect in FDA refers to the phenomenon that when parameters such as target velocity, frequency offset between transmitted carrier frequencies, number of accumulated pulses, number of transmitted array elements, and pulse repetition interval (PRI) reach a certain order of magnitude, the Doppler frequencies of the target echo received by different transmission channels will exhibit significant differences. Current research on FDA-MIMO radar is largely based on the assumption of ignoring the DS effect. This stems from the fact that existing theoretical frameworks typically focus on target scenarios with low velocity, small carrier frequency offset, and a small number of accumulated pulses. However, when the target velocity increases significantly, or when a large frequency offset is used to meet waveform orthogonality requirements, the traditional FDA-MIMO echo model based on the assumption of no DS effect will lead to a significant deterioration in system performance.

[0004] Furthermore, existing adaptive detection technologies rarely have specific optimization designs for high-speed moving targets. Especially when the target's velocity is ambiguous, traditional phased array or MIMO radar systems are prone to false alarms, severely degrading system performance. Such false alarms not only make it difficult to identify target attributes but may also mask the true target signal, leading to missed alarms. It is worth noting that the inherent DS effect of FDA-MIMO radar is equivalent to introducing staggered repetition rate pulses at the transmitter, giving it the potential to solve the velocity ambiguity problem and thus potentially achieving effective suppression of velocity-ambiguous false alarms. Summary of the Invention

[0005] This invention provides an adaptive detection method for high-speed targets based on the Doppler spread effect of FDA-MIMO radar. It aims to solve the problems of performance loss in high-speed scenes and lack of false alarm suppression methods for high-speed target velocity ambiguity caused by ignoring the DS (Doppler spread effect) in existing FDA-MIMO radars. This invention constructs an echo model of the DS effect and designs a detection mechanism by utilizing the characteristics of the equivalent staggered repetition frequency pulse of the DS effect, thereby achieving accurate detection and false alarm suppression of high-speed targets.

[0006] The technical solution adopted in this invention is: a high-speed target adaptive detection method based on the FDA-MIMO radar Doppler spread effect, which includes the following steps:

[0007] Step S1: Construct a frequency-controlled array radar that satisfies the frequency offset-waveform orthogonality condition, including a transmitter array and a receiver array;

[0008] Step S2: Calculate the transmitted signal of each transmitting element based on the array structure of the transmitting array; wherein the baseband waveform of each transmitting element satisfies frequency domain orthogonality.

[0009] Step S3: Based on the array structure of the receiver array and the transmitted signal of the transmitting array element, construct a target echo model based on the FDA-MIMO Doppler spread effect.

[0010] The expression for the target echo model is as follows:

[0011]

[0012] in, Represents the echo data matrix. Indicates the echo amplitude. Represents the extended matrix of the guiding vector. Represents the Doppler extended matrix. Represents the diagonalized Doppler matrix. This represents multi-pulse Gaussian noise. , , These represent the target's distance, azimuth, and velocity, respectively.

[0013] Step S4: Based on the constructed target echo model, design an adaptive detector based on the generalized likelihood ratio test;

[0014] The adaptive detector is set as follows:

[0015]

[0016] in, Indicates an adaptive detector. As an alternative hypothesis (the target exists). The null hypothesis is that the target does not exist. for The autocovariance matrix under the assumption, , The trace of the matrix is ​​represented by the superscript H, which is the conjugate transpose. The projection matrix is ​​a K-order identity matrix, where K is the set number of pulses. ; Indicates an adaptive detector The detection threshold;

[0017] Step S5: Based on the designed adaptive detector and the set false alarm rate... Obtain detection threshold ;

[0018] Step S6: Based on the detection threshold and adaptive detector Perform target detection.

[0019] Furthermore, in step S1, the frequency control array radar specifically refers to:

[0020] Set the number of transmitter elements in the transmitter array. The number of receiver array elements ;

[0021] The spacing between the transmitter elements of the transmitter array and the spacing between the receiver elements of the receiver array are both set to... ;

[0022] in, ,wavelength , As the reference carrier frequency, It is the speed of light.

[0023] Furthermore, in step S2, the transmission signal of the transmitting element is:

[0024] by The pulse repetition interval will be used to transmit the array elements. baseband waveform Add a pulse rectangular window and repeat Next, the launch array element was obtained. Baseband pulse train waveform :

[0025]

[0026] Among them, the number of the transmitting array elements , The number of elements in the transmitter array. For time variables, Number the pulse. The pulse width; For launching array elements The baseband waveform, the baseband waveform It has unit energy and satisfies frequency domain orthogonality;

[0027] Based on the baseband pulse train waveform Calculate the total transmitted signal after multi-carrier modulation:

[0028]

[0029] in, The natural base, The imaginary unit, For launching array elements The carrier frequency, of which the carrier frequency of the transmitting element 0 is the reference carrier frequency.

[0030] Furthermore, the baseband waveform Specifically, frequency domain orthogonality is satisfied as follows:

[0031]

[0032] in, Assigning the number to the transmitting array element, Indicates time delay. Indicates frequency offset. For launching array elements The baseband waveform.

[0033] Furthermore, in step S3, the guide vector extension matrix... Doppler extended matrix Diagonalized Doppler matrix and multi-pulse Gaussian noise Specifically:

[0034]

[0035] in, To receive the guide vector, For the launch guidance vector, For Kronecker product, It is a diagonal matrix. For pulse ( Doppler phase factor The Doppler phase vector, For pulse The statistical properties of the noise vector are expressed as follows: ,in Let Gaussian noise and interference be the covariance matrix. This represents a complex normal distribution, i.e., a zero-mean complex Gaussian distribution.

[0036] Furthermore, step S5 specifically includes:

[0037] Step S51: Using simulation, generate a single... An observation sample under the assumption And substitute it into the adaptive detector Calculate and obtain the threshold value. :

[0038] ,

[0039] Among them, the observation sample This refers to the echo data matrix generated by the simulation, with subscripts... Number the observed samples. For observation samples The autocovariance matrix;

[0040] Step S52: Perform Monte Carlo simulation, repeating step S51. Next, get indivual Given the assumed threshold values, sort them in ascending order to form an array. , ;

[0041] Step S53: Based on the set false alarm rate To construct the final detection threshold Among them, the selected array index , This is for floor function.

[0042] Furthermore, step S6 specifically includes:

[0043] Step S61: Perform air detection based on the transmission signals of the transmitting array and transmitting elements of the constructed frequency-controlled array radar;

[0044] Step S62: Receive the target echo signal using the receiver array of the frequency-controlled radar to obtain an echo data matrix containing the target. ;

[0045] Step S63: Calculate the autocovariance matrix ;

[0046] Step S64: Based on the constructed target echo model and the current unit under inspection Calculate the guide vector extension matrix of the current unit under inspection. Doppler extended matrix and diagonalized Doppler matrix and marked as , and ;in, This indicates the distance, azimuth, and velocity of the target in the current detection unit;

[0047] Step S65: Based on the adaptive detector and echo data matrix Calculate the detection output of the current unit under inspection. ;

[0048] Step S66: Output the detection results With detection threshold If a comparison is made, If the condition is met, the target is determined to exist; otherwise, the target is determined to not exist.

[0049] The technical solution provided by this invention brings at least the following beneficial effects:

[0050] (1) Improve the accuracy of high-speed scene modeling: Propose a target echo model of Doppler spread effect, correct the defects of simplified Doppler frequency processing in traditional models, clarify the quantitative correlation between target velocity, frequency offset and other parameters and Doppler spread effect, provide accurate echo characterization for high-speed / large frequency offset scenes, and avoid performance degradation caused by distortion of target echo model.

[0051] (2) Suppress false alarms due to velocity ambiguity: By utilizing the characteristics of the equivalent staggered repetition pulse of the Doppler extension effect, the true velocity of the target is inverted through the frequency difference of the multi-channel Doppler (de-velocity ambiguity), and the detection threshold is adaptively adjusted to significantly reduce the false alarm rate of high-speed targets (including velocity ambiguity state) and improve detection reliability. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 A flowchart of a high-speed target adaptive detection method based on the FDA-MIMO radar Doppler spread effect is provided for embodiments of the present invention;

[0054] Figure 2 This is a structural diagram of the FDA-MIMO radar transmitter and receiver array provided in an embodiment of the present invention;

[0055] Figure 3 This is a schematic diagram of the FDA-MIMO radar DS effect and the joint airspace distribution of the interference source transmission and reception, provided in an embodiment of the present invention.

[0056] Figure 4The detection probability diagram of the FDA-MIMO radar with and without interference, considering and ignoring the DS effect, provided for embodiments of the present invention;

[0057] Figure 5 The blind speed false alarm rate diagram is provided for the embodiment of the present invention, comparing the FDA-MIMO radar with phased array and MIMO radars. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be described in detail and completely below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Generally, the components of the embodiments of the present invention described and shown in the accompanying drawings can be arranged and designed using different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the present invention.

[0059] In one embodiment, such as Figure 1 As shown, the implementation steps of a high-speed target adaptive detection method based on the FDA-MIMO radar Doppler spread effect provided in this embodiment of the invention include:

[0060] Step S1: Construct a frequency-controlled array radar (i.e., FDA-MIMO radar) that satisfies the frequency offset-waveform orthogonality condition, including a transmitter array and a receiver array.

[0061] Step S2: Calculate the transmitted signal of each transmitting element based on the array structure of the transmitting array; wherein the baseband waveform of each transmitting element satisfies frequency domain orthogonality.

[0062] Step S3: Based on the array structure of the receiver array and the transmitted signal of the transmitting array element, construct a target echo model based on the FDA-MIMO Doppler spread effect.

[0063] The expression for the target echo model is as follows:

[0064]

[0065] in, Represents the echo data matrix. Indicates the echo amplitude. Represents the extended matrix of the guiding vector. Represents the Doppler extended matrix. Represents the diagonalized Doppler matrix. This represents multi-pulse Gaussian noise. , , These represent the target's distance, azimuth, and velocity, respectively.

[0066] Step S4: Based on the constructed target echo model, design an adaptive detector based on the generalized likelihood ratio test;

[0067] Step S5: Based on the designed adaptive detector, set the false alarm rate and obtain the detection threshold;

[0068] Step S6: Perform target detection based on the obtained detection threshold and the designed adaptive detector.

[0069] Specifically, step S1 includes the following sub-steps:

[0070] Step S11: Specify the number of transmitting array elements of the FDA-MIMO radar's transmitting array. They are numbered as follows The number of receiver array elements is: They are numbered as follows ,like Figure 2 As shown. Let The spacing between the transmitter array elements. The distance between the receiver array elements is [value], and the carrier frequency of the transmitter array elements is [value]. Among them, the number of the launch array elements , And the carrier frequency of the transmitting element 0. This is the reference carrier frequency. The target's range, azimuth, and velocity are as follows: , , .

[0071] In this embodiment, ,in, As the reference carrier frequency, The speed of light is and the wavelength is . .

[0072] Step S12: Configure each array element at the receiver with the corresponding transmission channel. Each mixer has a matching filter added to it.

[0073] Specifically, step S2 includes the following sub-steps:

[0074] Step S21, with The pulse repetition interval will be used to transmit the array elements. baseband waveform Add a pulse rectangular window and repeat Next, the launch array element was obtained. Baseband pulse train waveform :

[0075]

[0076] Among them, the number of the transmitting array elements , The number of elements in the transmitter array. For time variables, Number the pulse. The pulse width; For launching array elements The baseband waveform, the baseband waveform It has unit energy and satisfies frequency domain orthogonality.

[0077] Baseband waveform Having a unit of energy, that is: , This is a conjugate operation.

[0078] Baseband waveform Satisfying frequency domain orthogonality is specifically manifested in:

[0079]

[0080] in, Assigning the number to the transmitting array element, Indicates time delay. Indicates frequency offset. For launching array elements The baseband waveform.

[0081] Step S22: Based on the baseband pulse train waveform Calculate the total transmitted signal after multi-carrier modulation:

[0082]

[0083] in, The natural base, The imaginary unit, For launching array elements carrier frequency, Number the pulse. This represents the number of pulses.

[0084] Specifically, step S3 includes the following sub-steps:

[0085] Step S31, for distances of azimuth angle is Speed ​​is The goal, according to the The transmitted signal of the transmitting array element is calculated to reach the target after reflection. echo signal of each receiving array element The calculation formula is:

[0086]

[0087] in, The amplitude of the first echo. As the reference carrier frequency, At the speed of light, The spacing between the transmitter array elements. The spacing between the array elements at the receiving end. The natural base, The imaginary unit, Number the pulse. The number of pulses. The pulse repetition interval, Fast-time white noise, i.e. To save time.

[0088] Step S32: Based on the array structure of the receiving array, obtain the first... The first receiving element The output of each channel is split according to the pulse to obtain the matched output:

[0089]

[0090] In the formula, The second echo complex amplitude absorbs a constant. and matched filter gain, The Gaussian white noise after matched filtering follows a distribution , This represents the Gaussian noise power.

[0091] Step S33, combined and obtained Each receiving array element, One channel and The matched output of each pulse yields the echo data matrix:

[0092]

[0093] in, Represents the extended matrix of the guiding vector. Represents the Doppler extended matrix. Represents the diagonalized Doppler matrix. This represents multi-pulse Gaussian noise; its definitions are as follows:

[0094]

[0095] in, To receive the guide vector, For the launch guidance vector, For Kronecker product, It is a diagonal matrix. For pulse ( Doppler phase factor The Doppler phase vector, For pulse The statistical properties of the noise vector are expressed as follows: ,in Let Gaussian noise and interference be the covariance matrix. This represents a complex normal distribution, i.e., a zero-mean complex Gaussian distribution.

[0096] Specifically, step S4 includes the following sub-steps:

[0097] Step S41: Based on the obtained target echo model based on the FDA-MIMO Doppler spread effect, construct a binary hypothesis testing problem for target detection:

[0098]

[0099] in, As an alternative hypothesis (the target exists). The null hypothesis is used (the target does not exist). For the data to be detected, the echo complex amplitude... Covariance matrix of Gaussian noise and interference All parameters are unknown.

[0100] Step S42: Based on the obtained binary hypothesis testing problem for target detection, construct the generalized likelihood ratio test statistic. , is represented as:

[0101]

[0102] in, and They represent Assumptions and The probability density distribution function under the assumption, For the test statistic of generalized likelihood ratio The detection threshold.

[0103] To implement specific calculations, this application defines... Assumptions and The autocovariance matrices under the assumptions are as follows:

[0104]

[0105] in, for The autocovariance matrix under the assumption, for The autocovariance matrix under the assumption.

[0106] Step S43: Based on the obtained autocovariance matrix and Calculate the covariance matrix respectively. exist Assumptions and Maximum likelihood estimation under the assumptions and The specific calculation formula is as follows:

[0107]

[0108] Step S44: Based on the obtained and Maximum likelihood estimates of the covariance matrix under both assumptions, and calculation of the echo complex amplitude. Maximum likelihood estimator :

[0109]

[0110] in, The trace of the matrix is ​​represented by the superscript H, which is the conjugate transpose. The echo data matrix, the matrix Doppler extended matrix The abbreviation of matrix Extended matrix for guiding vector The abbreviation of matrix diagonalized Doppler matrix abbreviated form, The residual matrix is ​​as follows:

[0111]

[0112] In the formula, Projection matrix The orthogonal complement is calculated as follows:

[0113]

[0114] in, It is a K-order identity matrix;

[0115] Step S45: Based on the calculated echo recovery amplitude Maximum likelihood estimator , Maximum likelihood estimation of the autocovariance matrix under the given assumptions , Maximum likelihood estimation of the autocovariance matrix under the given assumptions Substitute the generalized likelihood ratio test statistic into the test statistic. And the calculation yields:

[0116]

[0117] in, for The negative logarithmic detector, also known as an adaptive detector, is expressed as follows:

[0118]

[0119] in, Indicates an adaptive detector The detection threshold.

[0120] Specifically, step S5 includes the following sub-steps:

[0121] Step S51: Using simulation, generate a single... Data under assumption The threshold value is obtained by substituting it into the detector calculation.

[0122]

[0123] in, This is an observation sample of multi-pulse Gaussian noise. For observation samples The autocovariance matrix, i.e. ;

[0124] Step S52: Perform Monte Carlo simulation, repeating step S51. ( ( ) times, obtained indivual The assumed threshold values ​​form an array. Sort them in ascending order to form an array. ;

[0125] Step S53: Because the detector is constant false alarm rate, the threshold value is determined by the given false alarm rate. The only certainty is based on the false alarm rate. Construct the final detection threshold ,in, For array The index is calculated as follows: ,in, This is for floor function.

[0126] Specifically, step S6 includes the following sub-steps:

[0127] Step S61: Perform air detection based on the transmission signals of the transmitting array and transmitting elements of the constructed frequency-controlled array radar array;

[0128] Step S62: Receive the target echo signal from the receiver array of the frequency-controlled radar array to obtain an echo data matrix containing the target. ;

[0129] Step S63: Calculate the autocovariance matrix ;

[0130] Step S64: Based on the constructed target echo model and the unit to be inspected Calculate the guide vector extension matrix of the unit under inspection respectively. , and Marked as , and ;

[0131] Step S65: Based on the designed adaptive detector and the obtained echo data matrix Calculate the adaptive detector of the unit to be inspected. Detection output :

[0132]

[0133] in, Indicates about The projection matrix;

[0134] Step S66: Output the detection results With detection threshold If a comparison is made, If the condition is met, the target is determined to exist; otherwise, the target is determined to not exist.

[0135] Step S67: Change the unit to be inspected and repeat steps S63-S66 until the feasible region of the unit to be inspected has been traversed.

[0136] To verify the effectiveness of the method proposed in this embodiment, the following simulation scenario was designed:

[0137] Target parameters: The target is located at a distance Azimuth At that location, its radial velocity is (The negative sign indicates movement away from the radar).

[0138] Interference source settings: Includes 1 suppression interference source (located at the azimuth angle) Noise-to-interference ratio ) and two deception interference sources (located respectively in and The noise-to-interference ratio is 1. ).in, , These represent the distances between the two deception / interference sources. , These represent the azimuth angles of the two deception interference sources.

[0139] Based on this simulation scenario, an FDA-MIMO radar echo signal model (involving DS effect) is constructed: the number of transmitter array elements is... Frequency offset The pulse repetition frequency is Accumulated pulse count The simulation results of the spatial power spectral density of the target and the interference source are as follows: Figure 3 As shown, the results indicate that, due to the DS effect, the target echo energy exhibits a dispersed distribution characteristic in the Doppler domain (unlike the energy concentration characteristic of traditional MIMO radar).

[0140] Comparative Experimental Design and Performance Verification: To demonstrate the advantages of the proposed method compared to detectors that ignore the DS effect, a Monte Carlo method was used for verification. The false alarm rate was defined as... ,use The detection threshold was obtained through the Monte Carlo experiment. Figure 4 The detection performance comparison curves for the two scenarios are given (the vertical axis represents the detection probability). The horizontal axis represents the signal-to-noise ratio (SNR). Here, GLRT represents the generalized likelihood ratio test, and the suffixes of the parameters in the figure are defined as follows: DS indicates "considering the DS effect," ND indicates "ignoring the DS effect"; SI indicates "strong interference scenario" (including the aforementioned suppression and deception interference), and NI indicates "no interference scenario." The results show that for radial velocity... The objective of this embodiment is to enable the DS detector to function effectively in both strong interference (SI) and no interference (NI) scenarios. All are improved compared to ND detectors The above (same false alarm probability) Under the given conditions, the ND detector failed to function properly in the SI scenario, thus verifying the improvement effect of considering the DS effect on high-speed target detection performance. Figure 4 In this context, GLRT stands for Generalized Likelihood Ratio Test.

[0141] To demonstrate the advantages of the proposed method (GLRT-FDA) compared to traditional radar, a comparison is made between the generalized likelihood ratio test (GLRT) detectors (denoted as GLRT-PA and GLRT-MIMO) used in traditional phased array radar and MIMO radar. After removing interference from the scene, the accumulated pulse count is... Among them, the speed fuzzy number is used express( To ensure search speed is accurate, (For fuzzy velocity). Simulation results are as follows: Figure 5As shown, the FDA-MIMO radar DS detector used in this embodiment... The false alarm probability at this location is significantly lower than that of GLRT-PA and GLRT-MIMO, effectively suppressing false alarms at fuzzy velocity. Although in There is a slight cluster of false alarms in the vicinity, but the range of ambiguity far exceeds the maximum unambiguous speed requirement of actual radar and does not affect the application.

[0142] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the foregoing embodiments have described the present invention in detail, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the embodiments of the present invention.

[0143] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A high-speed adaptive target detection method based on the FDA-MIMO radar Doppler spread effect, characterized in that, Includes the following steps: Step S1: Construct a frequency-controlled array radar that satisfies the frequency offset-waveform orthogonality condition, including a transmitter array and a receiver array; Step S2: Calculate the transmitted signal of each transmitting element based on the array structure of the transmitting array; wherein the baseband waveform of each transmitting element satisfies frequency domain orthogonality. Step S3: Based on the array structure of the receiver array and the transmitted signal of the transmitting array element, construct a target echo model based on the FDA-MIMO Doppler spread effect. The expression for the target echo model is as follows: in, Represents the echo data matrix. Indicates the echo amplitude. Represents the extended matrix of the guiding vector. Represents the Doppler extended matrix. Represents the diagonalized Doppler matrix. This represents multi-pulse Gaussian noise. , , These represent the target's distance, azimuth, and velocity, respectively. Step S4: Based on the constructed target echo model, design an adaptive detector based on the generalized likelihood ratio test; The adaptive detector is set as follows: in, Indicates an adaptive detector. As an alternative hypothesis, Assuming a null hypothesis, for The autocovariance matrix under the assumption, , The trace of the matrix is ​​represented by the superscript H, which stands for conjugate transpose. The projection matrix is ​​a K-order identity matrix, where K is the set number of pulses. ; Indicates an adaptive detector The detection threshold; Step S5: Based on the designed adaptive detector and the set false alarm rate... Obtain detection threshold ; Step S6: Based on the detection threshold and adaptive detector Perform target detection.

2. The high-speed target adaptive detection method based on the FDA-MIMO radar Doppler spread effect as described in claim 1, characterized in that, In step S1, the frequency control array radar specifically refers to: Set the number of transmitter elements in the transmitter array. The number of receiver array elements ; The spacing between the transmitter elements of the transmitter array and the spacing between the receiver elements of the receiver array are both set to... ; in, ,wavelength , As the reference carrier frequency, It is the speed of light.

3. The high-speed target adaptive detection method based on the FDA-MIMO radar Doppler spread effect as described in claim 1, characterized in that, In step S2, the transmission signal of the transmitting element is: by The pulse repetition interval will be used to transmit the array elements. baseband waveform Add a pulse rectangular window and repeat Next, the launch array element was obtained. Baseband pulse train waveform : Among them, the number of the transmitting array elements , The number of elements in the transmitter array. For time variables, Number the pulse. The pulse width; For launching array elements The baseband waveform, the baseband waveform It has unit energy and satisfies frequency domain orthogonality; Based on the baseband pulse train waveform Calculate the total transmitted signal after multi-carrier modulation: in, The natural base, The imaginary unit, For launching array elements The carrier frequency.

4. The high-speed target adaptive detection method based on the FDA-MIMO radar Doppler spread effect as described in claim 3, characterized in that, Baseband waveform Specifically, frequency domain orthogonality is satisfied as follows: in, Assigning the number to the transmitting array element, Indicates time delay. Indicates frequency offset. For launching array elements The baseband waveform.

5. The high-speed target adaptive detection method based on the FDA-MIMO radar Doppler spread effect as described in claim 1, characterized in that, In step S3, the guide vector extension matrix Doppler extended matrix Diagonalized Doppler matrix and multi-pulse Gaussian noise Specifically: in, To receive the guide vector, For the launch guidance vector, For Kronecker product, It is a diagonal matrix. For pulse Doppler phase factor The Doppler phase vector, For pulse The statistical properties of the noise vector are expressed as follows: ,in Let Gaussian noise and interference be the covariance matrix. Represents a complex normal distribution, pulse number .

6. The high-speed target adaptive detection method based on the FDA-MIMO radar Doppler spread effect as described in claim 1, characterized in that, Step S5 specifically includes: Step S51: Using simulation, generate a single... Data under assumption And substitute it into the adaptive detector Calculate and obtain the threshold value. : ， Among them, subscript Number the observed samples. For observation samples The autocovariance matrix; Step S52: Perform Monte Carlo simulation, repeating step S51. Next, get indivual Given the assumed threshold values, sort them in ascending order to form an array. , ; Step S53: Based on the set false alarm rate To construct the final detection threshold Among them, the selected array index , This is for floor function.

7. The high-speed target adaptive detection method based on the FDA-MIMO radar Doppler spread effect as described in claim 1, characterized in that, Step S6 specifically includes: Step S61: Perform air detection based on the transmission signals of the transmitting array and transmitting elements of the constructed frequency-controlled array radar; Step S62: Receive the target echo signal using the receiver array of the frequency-controlled radar to obtain an echo data matrix containing the target. ; Step S63: Calculate the autocovariance matrix ; Step S64: Based on the constructed target echo model and the current unit under inspection Calculate the guide vector extension matrix of the current unit under inspection. Doppler extended matrix and diagonalized Doppler matrix and marked as , and ;in, This indicates the distance, azimuth, and velocity of the target in the current detection unit; Step S65: Based on the adaptive detector and echo data matrix Calculate the detection output of the current unit under inspection. ; Step S66: Output the detection results With detection threshold If a comparison is made, If the condition is met, the target is determined to exist; otherwise, the target is determined to not exist.

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