A frequency agile method and device based on wideband interception

Abstract

The application belongs to the field of radar frequency domain anti-interference, and relates to a frequency agile method and device based on wideband interception, which comprises the following steps: S1, determining the frame task type of the previous frame of the radar; S2, when the frame task type of the previous frame is frame receiving frame task, executing normal frame task, otherwise executing frame receiving frame task; S3, calculating the wideband signal power spectrum from the data obtained through the frame receiving frame task; S4, when the interception frame monitoring signal coverage range is matched, determining the amplitude sampling point range of the wideband signal power spectrum corresponding to each frequency point of the radar operation, so as to calculate the average amplitude of each frequency point; S5, calculating the average value of the multiple average amplitudes of the latest statistics, and selecting the frequency points corresponding to the smaller multiple average values as the screening frequency points; S6, randomly selecting a frequency point from the screening frequency points to execute the frequency point agile of the normal frame task. The application improves the adaptive anti-interference ability of the radar in the complex electromagnetic environment.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of radar frequency domain anti-jamming, and particularly relates to a frequency agility method and device based on wideband interception. BACKGROUND

[0002] With the continuous progress of modern radar electronic countermeasure technology, the confrontation between jamming and anti-jamming is increasingly fierce. In the face of increasingly complex electromagnetic environment, radar urgently needs to improve its anti-jamming capability, reduce the influence of jamming on radar detection and tracking of valuable targets, so as to play a normal combat effectiveness in modern war. Frequency domain anti-jamming technology is an important field of radar anti-jamming measures, and frequency domain anti-jamming measures mainly include radar working frequency domain expansion, frequency agility, frequency diversity, adaptive frequency agility, etc.

[0003] Frequency agility, as a main measure of frequency domain anti-jamming, has strong anti-active suppression jamming capability, and is also a commonly used anti-jamming technology for airborne radar. The traditional frequency agility only makes regular or irregular changes in a certain frequency domain range, and does not consider the change of radar working electromagnetic environment, and the effect of anti-predictive aiming jamming and distributed jamming is not good. From the perspective of radar target detection, the radar has an optimal working frequency for a specific electromagnetic environment. Through the wideband interception mode, the jamming frequency points are removed in real time, the automatic tracking of the optimal working frequency of the radar is realized, and the technical direction is provided for the airborne radar to adapt to the complex electromagnetic field environment and resist aiming jamming and distributed jamming, and reasonably utilize the frequency spectrum resources. SUMMARY

[0004] In order to solve the above problems, the application provides a frequency agility method and device based on wideband interception, so as to adaptively extract the weakest interference frequency band region and screen the corresponding frequency points, and complete the radar frequency agility.

[0005] The first aspect of the application provides a frequency agility method based on wideband interception, mainly comprising:

[0006] Step S1, determining the frame task type of the last frame of the radar, and the frame task type includes a frame collection frame task and a normal frame task;

[0007] Step S2, when the frame task type of the last frame is the frame collection frame task, turning to step S6 to perform the normal frame task, and when the frame task type of the last frame is the normal frame task, turning to step S3 to perform the frame collection frame task;

[0008] Step S3, calculating the wideband signal power spectrum from the data obtained through the frame collection frame task;

[0009] Step S4, for each frequency point of the radar operation, when the frequency coverage thereof falls completely within the coverage of the monitoring frame, the range of amplitude sample points of the wideband signal power spectrum corresponding to the frequency point is determined to calculate the average amplitude;

[0010] Step S5, for each frequency point, the average value of the Row average amplitudes of the most recently performed frame collection task is calculated, and the frequency points corresponding to the smaller average values are selected as the screening frequency points returned by the monitoring frame task;

[0011] Step S6, a frequency point is randomly selected from the screening frequency points returned by the monitoring frame task, and the operating frequency point of the normal frame is controlled to jump to the random frequency point when the normal frame task is performed.

[0012] Preferably, step S2 further comprises:

[0013] Step S21, obtaining the determination parameter T of the frame task type INR : T INR = T monitor + 1, wherein T monitor is the monitoring frame task period, which is previously configured to be less than the shortest period of the normal frame task;

[0014] Step S22, judging the interval of the frame interrupt signals between the current frame and the previous frame, if the interval is less than the determination parameter T INR , the frame task type of the previous frame is determined as the frame collection task, and the current frame performs the normal frame task, otherwise, the current frame performs the frame collection task.

[0015] Preferably, step S3 further comprises:

[0016] Step S31, unpacking the data obtained through the frame collection task to obtain original pulse sampling data of a plurality of sample points of the IQ two-way;

[0017] Step S32, performing direct current operation on the original pulse sampling data of the IQ two-way, and then performing vector combination;

[0018] Step S33, performing time-frequency conversion on the data after vector combination to obtain a single pulse wideband signal power spectrum.

[0019] Preferably, step S4 further comprises:

[0020] Step S41, calculating the middle sample point K i in the wideband signal power spectrum P(k) corresponding to the frequency point numbered F i :

[0021]

[0022] wherein f0 is the starting frequency of the radar operation, Fi is the number of the ith frequency point, B freq is the frequency point interval, f low is the lower limit of the signal monitoring coverage of the detection frame, N is the number of pulse sampling points in the time domain, and k is the sampling point in the frequency domain;

[0023] Step S42, according to the amplitude sampling point number N of the single frequency point gap calculating the average amplitude P corresponding to the frequency point * (i):

[0024]

[0025] Preferably, step S5 further comprises:

[0026] Step S51, removing the frequency points corresponding to the higher average values of the average values of the latest d average amplitudes, wherein d<ROW.

[0027] The second aspect of the application provides a frequency agile device based on wideband detection, mainly comprising:

[0028] a frame task type determination module for determining the frame task type of the last frame of the radar, wherein the frame task type comprises a frame detection frame task and a normal frame task;

[0029] an alternating control module for executing the normal frame task when the frame task type of the last frame is the frame detection frame task, and executing the frame detection frame task when the frame task type of the last frame is the normal frame task;

[0030] a wideband signal power spectrum calculation module for calculating the wideband signal power spectrum from the data obtained through the frame detection frame task;

[0031] an average amplitude calculation module for determining the amplitude sampling point range of the wideband signal power spectrum corresponding to each frequency point of the radar when the frequency coverage range of the frequency point completely falls within the monitoring signal coverage range of a detection frame, so as to calculate the average amplitude;

[0032] a frequency point screening module for calculating the average value of the Row average amplitudes of the latest frame detection frame task for each frequency point, and selecting the frequency points corresponding to the smaller average values as the screening frequency points returned by the detection frame task;

[0033] a frequency agile module for randomly selecting a frequency point from the screening frequency points returned by the detection frame task, and controlling the frequency agile device to change the working frequency point of the normal frame to the random frequency point when the normal frame task is executed.

[0034] Preferably, the alternating control module comprises:

[0035] A determination parameter acquisition unit is configured to acquire a determination parameter T of a frame task type INR : T INR = T monitor + 1, wherein T monitor is a detection frame task period, which is previously configured to be less than a shortest period of a normal frame task;

[0036] A signal interval comparison unit is configured to judge a frame interruption signal interval of a current frame and a previous frame, if the signal interval is less than the determination parameter T INR , the frame task type of the previous frame is determined as a frame receiving frame task, the current frame executes a normal frame task, otherwise, the current frame executes a frame receiving frame task.

[0037] Preferably, the wideband signal power spectrum calculation module comprises:

[0038] A packet disassembling unit is configured to disassemble data acquired through the frame receiving frame task to obtain original pulse sampling data of multiple sampling points of the IQ two-way;

[0039] A direct current removing unit is configured to perform a direct current removing operation on the original pulse sampling data of the IQ two-way, and then perform vector combination;

[0040] A time-frequency conversion unit is configured to perform time-frequency conversion on the data after vector combination to obtain a single pulse wideband signal power spectrum.

[0041] Preferably, the average amplitude calculation module comprises:

[0042] A frequency domain middle sampling point calculation unit is configured to calculate a middle sampling point K i in a wideband signal power spectrum P(k) corresponding to a frequency point numbered F i :

[0043]

[0044] wherein f0 is a radar working start frequency, F i is a number of the i-th frequency point, B freq is a frequency point interval, f low is a lower limit of a signal monitoring coverage range of the detection frame, N is a number of pulse sampling points in time domain, and k is a sampling point in frequency domain;

[0045] An average amplitude calculation unit is configured to calculate an average amplitude P gap (i) of a single frequency point according to a number N * of amplitude sampling points of the frequency point:

[0046]

[0047] Preferably, the frequency agile module comprises:

[0048] The frequency point elimination unit is used to eliminate the frequency points corresponding to the higher average values ​​among the most recent d average amplitude values, where d <ROW。

[0049] This application improves the radar's adaptive anti-jamming capability in complex electromagnetic environments. Attached Figure Description

[0050] Figure 1 This is a flowchart of a preferred embodiment of the frequency agility method based on broadband detection in this application.

[0051] Figure 2 This is a map showing the frequency coverage of broadband surveillance.

[0052] Figure 3 This is a graph showing the cumulative spectrum results of broadband intercepted frames.

[0053] Figure 4 This is a schematic diagram of the statistical results of the amplitude distribution of broadband detection frequency points.

[0054] Figure 5 This is a schematic diagram illustrating the frequency agility and anti-interference effect. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0056] The first aspect of this application provides a frequency agility method based on broadband detection, such as... Figure 1 As shown, it mainly includes:

[0057] Step S1: Determine the frame task type of the previous radar frame, whereby the frame task type includes frame reception task and normal frame task.

[0058] Step S2: When the frame task type of the previous frame is frame receiving task, proceed to step S6 to execute normal frame task; when the frame task type of the previous frame is normal frame task, proceed to step S3 to execute frame receiving task.

[0059] Step S3, calculate the wideband signal power spectrum of the data obtained by the frame collection task;

[0060] Step S4, for each frequency point of the radar operation, when its frequency coverage completely falls into the coverage of the monitoring signal of the detection frame, determine the amplitude sampling point range of the wideband signal power spectrum corresponding to the frequency point, to calculate the average amplitude;

[0061] Step S5, for each frequency point, calculate the average value of the Row average amplitude of the most recently performed frame collection task, select the frequency points corresponding to the smaller average values, as the screening frequency points returned by the detection frame task;

[0062] Step S6, randomly select a frequency point from the screening frequency points returned by the detection frame task, and control the normal frame to be quickly changed to the random frequency point when performing the normal frame task.

[0063] The present application can remove the interference frequency points in real time through the wideband detection method, and realize the automatic tracking of the optimal working frequency of the radar. Specifically, in steps S1 and S2, the frame collection frame and the normal frame are alternately operated. In steps S3-S5, the frame collection frame is used to realize the electromagnetic environment monitoring, complete the real-time sampling, processing and analysis of the external working electromagnetic environment, adaptively extract the weakest interference frequency band region and screen the corresponding frequency points, and provide the spectrum basis for the adaptive frequency quick change. In step S6, the normal frame is used to perform the normal search task, randomly select a frequency point from the frequency point pool composed of the screened corresponding frequency points to complete the frequency quick change, and realize the frequency quick change anti-interference.

[0064] Before performing the above steps, the frame collection frame signal parameters need to be designed, mainly including:

[0065] (1) Wideband detection frame monitoring coverage frequency bandwidth B monitor The wideband detection frame signal parameter design is determined according to the wideband detection coverage frequency bandwidth. Based on the consideration of completing the interference situation statistics of the radar working frequency band in the shortest time, the maximum working bandwidth of the radar receiver is used as the wideband detection frame monitoring coverage frequency bandwidth B monitor , unit: Hz. According to the Nyquist sampling theorem, the sampling rate ω monitor of the wideband detection frame signal, unit: Hz, needs to meet B monitor < ω monitor . At the same time, the frequency F monitor of the wideband detection frame signal needs to be designed. Since the time domain sampling of the signal is the periodic extension of the spectrum, F monitor needs to be the center frequency of the wideband detection coverage frequency. According to the above parameters, the detection frequency point F monitor [N monitor ] needed to complete the interference situation statistics of the radar working frequency band can be calculated, N monitorIndicates the total number of broadband receiving frequencies, see reference. Figure 2 . B radar Indicates the radar operating frequency band, B radar =FB h -FB l ,FB h Indicates the upper limit of the radar's operating frequency band, FB l Indicates the lower limit of the radar's operating frequency band. F monitor The detection coverage of [0] is [FB] l ,F monitor [0]+B monitor / 2],F monitor [1] has a detection coverage area of ​​[F] monitor [1]-B monitor / 2,F monitor [1]+B monitor / 2], and so on, F monitor [N monitor The detection coverage area of ​​] is [F monitor [N monitor ]-B monitor / 2,FB h For example, radar operating frequency band B. radar The designed detection frame monitoring coverage frequency bandwidth B is 800MHz (from 0-800MHz). monitor If the frequency is 200MHz, then a total of 4 detection frequencies F need to be designed. monitor [0]-F monitor [3] is needed to cover this, where F monitor [0] has a coverage range of 0-200MHz and a center frequency of 100MHz. Here, F can be used. monitor [0] = 100MHz is used to represent this; similarly, F monitor [1] = 300MHz, F monitor [2] = 500MHz, F monitor [3] = 700MHz.

[0066] (2) Pulse repetition period PRI of the broadband detection frame signal monitor If the unit is milliseconds, and the number of pulses in a wideband detection frame is M, then the corresponding frame period of the wideband detection frame is T. monitor =PRI monitor ×M, in milliseconds, to avoid wideband detection frames affecting normal search frame operation and signal processing, T monitor It should be as small as possible compared to the normal frame period T. normal This is the key parameter in step S2 for determining whether the previous frame was a normal frame task or a frame receiving task.

[0067] Secondly, the number of sampling points of the wideband intercept frame pulse is N, N = PRI monitor ×ω monitor . Since the wideband signal is sampled and then Fourier transformed (FFT), the obtained spectrum is discrete spectrum, and the interval between the signal spectrums, i.e. the spectral resolution ΔB, is in units of hertz, then ΔB = ω monitor / N; for real-time detection of the frequency signal of the normal search frame, the spectral resolution ΔB of the wideband intercept frame needs to be less than the signal bandwidth B normal of the normal search frame, i.e. ΔB < B normal , so when setting the pulse repetition period of the wideband intercept frame, the following needs to be met: 1 / PRI monitor < B normal .

[0068] In addition, the larger PRI monitor is, the larger the number of sampling points N is, and the better the spectral resolution ΔB is, but the larger N is, the larger the frame period T monitor of the wideband intercept frame is, and the signal processing time is correspondingly increased, and the impact on the normal search work of the radar is larger. Therefore, when setting the pulse repetition period PRI monitor of the wideband intercept frame, the spectral resolution should be ensured, and PRI monitor should be avoided from being too large to affect the normal search work of the radar.

[0069] As described above, the frame collection frame is set to contain M pulses, each pulse contains N sampling points, and the pulse repetition period PRI monitor of each pulse is limited by the above three aspects.

[0070] After setting the above frame collection frame, return to step S2 to design an alternating polling strategy of the normal frame task and the intercept frame task. In some optional embodiments, step S2 further includes:

[0071] Step S21, obtaining a determination parameter T INR of the frame task type: T INR = T monitor + 1, wherein T monitor is the intercept frame task period, which is previously configured to be less than the shortest period of the normal frame task;

[0072] Step S22, judging the frame interruption signal interval between the current frame and the previous frame, if the frame interruption signal interval is less than the determination parameter T INR , then the frame task type of the previous frame is determined as the frame collection frame task, and the current frame executes the normal frame task, otherwise, the current frame executes the frame collection frame task.

[0073] The above process can be controlled by a frame receiving flag in the program, that is, when the previous frame is a normal frame, the frame receiving flag is set to 0, the current frame performs a normal frame task, otherwise the detection flag is set to 1, and the current frame performs a detection frame task. In addition, it should be noted that at the beginning of the program, the first frame of the radar power-on should be set as a normal frame.

[0074] Step S3 starts to perform a frame receiving frame task, the frame receiving frame task sets radar frame receiving working parameters, executes steps S3 to S5, and sends radar normal working parameter information, such as channel information and frequency point information of a normal frame, which has been set by the last normal frame task, to the radar system. In order to accurately monitor external environmental interference, the antenna unit should be kept in a passive receiving mode when performing a detection task, and in order to avoid introducing channel consistency error, the same channel and the same channel gain should be kept to complete wideband signal sampling during the detection frame task, that is, the radio frequency unit keeps a wideband single-channel receiving mode.

[0075] In some optional embodiments, step S3 further includes:

[0076] Step S31 unpacks the data obtained through the frame receiving frame task to obtain original pulse sampling data of IQ two-way multiple sampling points;

[0077] Step S32 performs direct current operation on the original pulse sampling data of IQ two-way, and then performs vector combination;

[0078] Step S33 performs time-frequency conversion on the data after vector combination to obtain a single-pulse wideband signal power spectrum.

[0079] In this embodiment, during the wideband detection frame working period, the signal processing completes the cache work of the A / D sampling pulse sequence data X0, X1, X m ,…,X M-1 of the aforementioned M pulses, and unpacks when the last A / D sampling pulse sequence data cache is completed in the wideband detection frame, and in step S31, original pulse sampling data x I (m,n) and x Q (m,n) of IQ two-way N sampling points are obtained, wherein x I (m,n) represents I-way data of the nth sampling point of the mth pulse, and x Q (m,n) represents Q-way data of the nth sampling point of the mth pulse. Then in step S32, the IQ two-way data direct current operation is completed by the following formula to smooth the signal, and the IQ two-way data after direct current operation is obtained. and

[0080]

[0081] After that, IQ two-way data vector combination is completed: Wherein, j is imaginary part symbol.

[0082] Finally, time-frequency conversion of wideband time domain signal x(m, n) is completed in step S33 to obtain single pulse wideband signal power spectrum. Specifically, first, discrete Fourier transform is performed on x(m, n) by the following formula to obtain equidistant sampling results X(m, k) of continuous signal spectrum:

[0083] X(m, k) = FFT(x(m, n)), 0≤k≤N-1;

[0084] Secondly, the X(m, k) signal spectrum result is modulated to convert the power value result P(m, k), that is, P(m, k) = |X(m, k)|; wherein k is a sampling point in the frequency domain, and finally, the power value results P(m, k) of the above m pulses are accumulated according to the k value to form the first spectrum cumulative result P(k), that is, P(k) = P(0, k) + P(1, k) + … + P(m-1, k). The spectrum cumulative result is shown in Figure 3 , that is, Figure 3 Each discrete k value (abscissa) corresponds to a wideband signal power spectrum P(k).

[0085] With the wideband signal power spectrum P(k), the mean value of different frequency bands can be calculated in step S4. First, frequency point matching needs to be completed, that is, the radar operating frequency point is matched to the sampling point range of the wideband signal power spectrum P(k), so that the power mean value of the power values of multiple sampling points in the sampling point range is calculated.

[0086] Frequency point matching mainly calculates the range of each frequency point, which is represented by F i here, the sequence number of the i-th frequency point is Figure 4 40 frequency points are given, and the frequency point sequence numbers are 1-40, which are different from the frame receiving frame detection frequency point F monitor [N monitor ], here the 40 frequency points are narrowband, and the frame receiving frame frequency point is wideband. Therefore, this step mainly determines which wideband the narrowband falls into, and the signal monitoring coverage range of the frame receiving frame has been given. Of course, the frame receiving frame frequency point number F monitorx can also be used for fast calculation, that is, the lower limit of the monitoring range f low = f0+F monitorx *B freq -B monitor / 2; the upper limit of the monitoring range f high = f0+F monitorx *B freq +B monitor / 2; where f0 is the radar's starting frequency, i.e., the frequency of the radar's operating frequency point 0 (or Figure 4 (frequency point 1 in the middle), B freq The frequency spacing is used. The coverage of the 40 frequency points in the narrowband is achieved using the same method, utilizing the index F of each frequency point. i and frequency spacing B freq Normal frame signal bandwidth B normal Calculated, that is:

[0087]

[0088] Then, for each frequency point where the radar operates, determine its frequency coverage range. Whether it falls completely within the coverage area of ​​a detection frame monitoring signal [f] low ,f high Within, for example, if the current frequency point F i Simultaneously satisfy

[0089]

[0090] This indicates that the frequency point is within the coverage area of ​​the detected signal, and F i ≠F normal Calculate the average power value over time. Figure 3 The amplitude is expressed as a value, so this can also be referred to as calculating the average amplitude.

[0091] In some alternative implementations, step S4 further includes:

[0092] Step S41, calculate number F i The frequency point corresponds to the intermediate sampling point K in the broadband signal power spectrum P(k). i :

[0093]

[0094] Where f0 is the radar's starting operating frequency, F i Let B be the number of the i-th frequency point. freq For frequency point spacing, f low The signal monitoring coverage of the detected frame is the lower limit, where N is the number of pulse sampling points in the time domain and k is the number of sampling points in the frequency domain;

[0095] Step S42: Based on the amplitude sampling point N of a single frequency point gap Calculate the average amplitude P corresponding to this frequency point. * (i):

[0096]

[0097] In this embodiment, each frequency point is numbered Fi corresponding to an average amplitude P * (i) is 0. i normal i corresponding to an average amplitude P * (i) is 0.

[0098] The size of the single average amplitude P * (i) cannot well perform the frequency point screening, therefore, in step S5, the application calculates the average value of the average amplitudes of the multiple frame collection tasks to perform the frequency point screening.

[0099] In order to count the statistical results of the multiple frame collection tasks, the program can design a variable T(i) to track the frequency point number F i corresponding to an average amplitude P * (i) of each frame collection task, that is, when the average amplitude P * (i) is not 0, the variable T(i) of the frame collection task is 1, otherwise it is 0, so that the average value of the average amplitudes P * (i) of the Row frame collection tasks can be calculated by adding the average amplitudes P(i) and then dividing by the accumulated T(i), where Row is usually 100, and when the program is initially executed without 100 data, the number of calculations is as much as the number of data.

[0100] Figure 4 The average value of the average amplitudes of the 40 frequency points is given in Table 1, and then in step S5, the frequency points corresponding to the smaller multiple average values are selected as the screening frequency points returned by the frame collection task, for example, in Table 2, 5 frequency points are selected from the 40 statistical frequency points as the screening frequency points and added to the frame collection screening frequency point pool. Figure 4 The frame collection screening frequency point pool is used for the subsequent step S6 to perform the normal frame task, and when the program is initially not executed to step S5, multiple frequency points can be selected from all frequency points at equal intervals to fill the frame collection screening frequency point pool.

[0101] In some optional embodiments, step S5 further includes:

[0102] Step S51, remove the frequency points corresponding to the higher multiple average values in the average values of the average amplitudes of the last d times, where d<ROW.

[0103] ​In this embodiment, to avoid the influence of the frequency point with abnormal amplitude in the latest wideband interception on the statistical result, the average value of the statistical calculation result of the latest d frame interception is calculated according to the above steps, where d is usually 2, that is, the average value of the average amplitude of the previous 100 times is calculated in step S5, and the high value is selected from the average value of the average amplitude of the previous 2 times in the same way, and the low value selection operation in step S5 is not performed. Assuming that the 35th, 36th and 37th high value frequency points are selected, the amplitude of the three frequency points can be set to the maximum value in the program design, so that the three frequency points will not be selected in the low value selection in the subsequent step S5. In addition, the radar training frequency point and the working frequency point of the previous normal search frame can also be eliminated, that is, the amplitude of the training frequency point and the normal search frame frequency point is set to the maximum value.

[0104] After completing the frame interception task, return to Figure 1 In step S6, the normal frame task saves the frequency point F normal of the previous normal frame. temp A frequency point F temp is randomly selected from the interception screening frequency point pool. temp If any one of the following two conditions is met, the frequency point of the current normal frame is updated to F

[0105] (1) F temp ≠ F normal .

[0106] (2) The execution frequency of the randomly selected frequency point from the interception screening frequency point pool is greater than the maximum execution frequency in one frame.

[0107] Through the above method, the frequency point F temp is determined to be one of the frequency points with the smallest interference, and the radar working frequency is constantly changed to the frequency with the smallest interference to perform the target detection and tracking task, so as to realize frequency change anti-jamming.

[0108] Figure 5 The anti-jamming effect diagram is given, after injecting interference at the 23rd frequency point, the radar working frequency range for performing the normal search and tracking task is automatically changed from the 20th to 25th frequency point to the 28th to 33rd frequency point, effectively avoiding the interference frequency band. The results show that the interference frequency point elimination and frequency change method based on wideband interception is realized.

[0109] The application has the following advantages:

[0110] 1. Reasonably and effectively use the radar wideband signal resource, adopt the radar wideband single channel mode to realize the wideband electromagnetic environment monitoring function, and record the wideband spectrum data in real time.

[0111] 2. Based on the wideband electromagnetic environment detection result, the interference frequency points are removed, a plurality of selected frequency points with less interference are screened to form a screening frequency point pool, and the radar selects a frequency point from the screening frequency point pool to realize frequency agility when performing normal search and tracking task, so that the radar can effectively resist the active deception jamming, direct amplification type and sweep type narrowband aiming suppression jamming across the heavy frequency;

[0112] 3. The wideband signal detection frame and the radar normal search and tracking frame are alternately polled in the working mode, the real-time update of the interference condition of the radar working frequency band is realized, the normal search and tracking work of the radar is not affected, and the adaptive anti-interference ability of the radar in the complex electromagnetic environment is improved;

[0113] 4. The adaptive interference frequency point removal and frequency agility anti-interference technology are used to make the radar realize more targeted interference frequency band avoidance, and improve the target search and tracking performance of the radar.

[0114] The second aspect of the application provides a frequency agility device based on wideband detection corresponding to the above method, mainly comprising:

[0115] A frame task type determination module is configured to determine the frame task type of the last frame of the radar, and the frame task type comprises a frame detection frame task and a normal frame task.

[0116] An alternating control module is configured to perform a normal frame task when the frame task type of the last frame is a frame detection frame task, and perform a frame detection frame task when the frame task type of the last frame is a normal frame task.

[0117] A wideband signal power spectrum calculation module is configured to calculate the wideband signal power spectrum based on the data obtained through the frame detection frame task.

[0118] An average amplitude calculation module is configured to determine the amplitude sampling point range of the wideband signal power spectrum corresponding to each frequency point of the radar when the frequency coverage range of the frequency point completely falls within the coverage range of the detection frame monitoring signal, so as to calculate the average amplitude.

[0119] A frequency point screening module is configured to calculate the average value of the Row average amplitude of each frequency point in the last frame detection frame task, select a plurality of frequency points corresponding to the smaller average values as the screening frequency points returned by the detection frame task.

[0120] A frequency agility module is configured to randomly select a frequency point from the screening frequency points returned by the detection frame task, and control the working frequency point of the normal frame to be agile to the random frequency point when performing the normal frame task.

[0121] In some optional embodiments, the alternating control module comprises:

[0122] A determination parameter acquisition unit is configured to acquire a determination parameter T of the frame task type.INR : T INR = T monitor + 1, wherein, T monitor is a detection frame task period, which is configured in advance to be less than the shortest period of a normal frame task;

[0123] a signal interval comparison unit, configured to judge the frame interruption signal interval between a current frame and a previous frame, if the interval is less than a judgment parameter T INR , then the frame task type of the previous frame is determined as a frame collection frame task, and the current frame executes a normal frame task, otherwise, the current frame executes a frame collection frame task.

[0124] In some optional embodiments, the wideband signal power spectrum calculation module comprises:

[0125] a packet disassembling unit, configured to disassemble data obtained through the frame collection frame task to obtain original pulse sampling data of multiple sampling points of the IQ two paths;

[0126] a direct current removing unit, configured to perform a direct current removing operation on the original pulse sampling data of the IQ two paths, and then perform vector combination;

[0127] a time-frequency conversion unit, configured to perform time-frequency conversion on the data after vector combination to obtain a single pulse wideband signal power spectrum.

[0128] In some optional embodiments, the average amplitude calculation module comprises:

[0129] a frequency domain middle sampling point calculation unit, configured to calculate the middle sampling point K i in the wideband signal power spectrum P(k) corresponding to a frequency point numbered F i :

[0130]

[0131] wherein, f0 is a radar working start frequency, F i is the number of the i-th frequency point, B freq is a frequency point interval, f low is a lower limit of a signal monitoring coverage range of the detection frame, N is the number of pulse sampling points in the time domain, and k is a sampling point in the frequency domain;

[0132] an average amplitude calculation unit, configured to calculate the average amplitude P * (i) corresponding to a single frequency point according to the amplitude sampling point number N gap of the frequency point:

[0133]

[0134] In some optional embodiments, the frequency agile module comprises:

[0135] The frequency point elimination unit is configured to eliminate frequency points corresponding to a plurality of average values higher than an average value of the last d average values, wherein d < ROW.

[0136] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A frequency agility method based on broadband detection, characterized in that, include: Step S1: Determine the frame task type of the previous radar frame, whereby the frame task type includes detection frame task and normal frame task. Step S2: When the frame task type of the previous frame is a detection frame task, proceed to step S6 to execute the normal frame task; when the frame task type of the previous frame is a normal frame task, proceed to step S3 to execute the detection frame task. Step S3: Calculate the broadband signal power spectrum from the data acquired through the detection frame task; Step S4: For each frequency point where the radar is operating, when its frequency coverage falls completely within the coverage of a detection frame monitoring signal, determine the amplitude sampling point range of the broadband signal power spectrum corresponding to that frequency point in order to calculate the average amplitude. Step S5: For each frequency point, calculate the average value of the Row average amplitude of the most recent reconnaissance frame task, and select the frequency points corresponding to the smaller average values ​​as the filter frequency points returned by the reconnaissance frame task. Step S6: Randomly select a frequency point from the filtered frequency points returned by the detection frame task, and when executing the normal frame task, control the working frequency point of the normal frame to quickly switch to the random frequency point.

2. The frequency agility method based on broadband detection as described in claim 1, characterized in that, Step S2 further includes: Step S21: Obtain the frame task type determination parameter T INR :T INR =T monitor +1, where T monitor The detection frame task period is pre-configured to be shorter than the minimum period of the normal frame task. Step S22: Determine the frame interruption signal interval between the current frame and the previous frame. If it is less than the determination parameter T... INR If the frame task type of the previous frame is determined to be a reconnaissance frame task, the current frame will execute a normal frame task; otherwise, the current frame will execute a reconnaissance frame task.

3. The frequency agility method based on broadband detection as described in claim 1, characterized in that, Step S3 further includes: Step S31: Depacket the data obtained through the detection frame task to obtain the raw pulse sampling data of multiple sampling points in the I and Q channels; Step S32: Perform DC removal on the raw pulse sampling data of the I and Q channels, and then perform vector combination; Step S33: Perform time-frequency conversion on the data after vector combination to obtain the power spectrum of the single-pulse broadband signal.

4. The frequency agility method based on broadband detection as described in claim 1, characterized in that, Step S4 further includes: Step S41, calculate the number F i The frequency point corresponds to the intermediate sampling point K in the broadband signal power spectrum P(k). i : ； Where f0 is the radar's starting operating frequency, F i Let B be the number of the i-th frequency point. freq For frequency point spacing, f low The signal monitoring coverage range of the detected frame is the lower limit, where N is the number of pulse sampling points in the time domain and K is the number of sampling points in the frequency domain; Step S42: Based on the amplitude sampling point N of a single frequency point gap Calculate the average amplitude P corresponding to this frequency point. * (i): 。 5. The frequency agility method based on broadband detection as described in claim 1, characterized in that, Step S5 further includes: Step S51: Remove the frequency points corresponding to the higher average values ​​among the most recent d average amplitudes, where d <ROW。 6. A frequency agility device based on broadband detection, characterized in that, include: The frame task type determination module is used to determine the frame task type of the previous radar frame, which includes detection frame task and normal frame task. The alternation control module is used to execute the normal frame task when the frame task type of the previous frame is a detection frame task, and to execute the detection frame task when the frame task type of the previous frame is a normal frame task. The broadband signal power spectrum calculation module is used to calculate the broadband signal power spectrum from the data acquired through the detection frame task. The average amplitude calculation module is used to determine the amplitude sampling point range of the broadband signal power spectrum corresponding to each frequency point of radar operation when its frequency coverage falls completely within the coverage range of a detection frame monitoring signal, so as to calculate the average amplitude. The frequency point filtering module is used to calculate the average value of the Row average amplitude of the most recent reconnaissance frame task for each frequency point, and select the frequency points corresponding to the smaller average values ​​as the filtered frequency points returned by the reconnaissance frame task. The frequency agility module is used to randomly select a frequency point from the filtered frequency points returned by the detection frame task, and control the working frequency point of the normal frame to agilely change to the random frequency point when executing the normal frame task.

7. The frequency agility device based on broadband detection as described in claim 6, characterized in that, The alternation control module includes: The determination parameter acquisition unit is used to acquire the determination parameter T of the frame task type. INR :T INR =T monitor +1, where T monitor The detection frame task period is pre-configured to be shorter than the minimum period of the normal frame task. The signal interval comparison unit is used to determine the frame interruption signal interval between the current frame and the previous frame. If it is less than the determination parameter T, the comparison unit will determine the frame interruption signal interval between the current frame and the previous frame. INR If the frame task type of the previous frame is determined to be a reconnaissance frame task, the current frame will execute a normal frame task; otherwise, the current frame will execute a reconnaissance frame task.

8. The frequency agile device based on broadband detection as described in claim 6, characterized in that, The broadband signal power spectrum calculation module includes: The unpacking unit is used to unpack the data acquired through the detection frame task to obtain the raw pulse sampling data with multiple sampling points in both I and Q channels; The DC removal unit is used to perform DC removal on the raw pulse sampling data of the I and Q channels, and then perform vector combination. The time-frequency conversion unit is used to perform time-frequency conversion on the data after vector combination to obtain the power spectrum of a single-pulse broadband signal.

9. The frequency agile device based on broadband detection as described in claim 6, characterized in that, The average amplitude calculation module includes: The frequency domain intermediate sampling point calculation unit is used to calculate the number F. i The frequency point corresponds to the intermediate sampling point K in the broadband signal power spectrum P(k). i : ； Where f0 is the radar's starting operating frequency, F i Let B be the number of the i-th frequency point. freq For frequency point spacing, f low The signal monitoring coverage range of the detected frame is the lower limit, where N is the number of pulse sampling points in the time domain and K is the number of sampling points in the frequency domain; The average amplitude calculation unit is used to calculate the amplitude based on the number of sampling points N at a single frequency point. gap Calculate the average amplitude P corresponding to this frequency point. * (i): 。 10. The frequency agility device based on broadband detection as described in claim 6, characterized in that, The frequency agility module includes: The frequency point elimination unit is used to eliminate the frequency points corresponding to the higher average values ​​among the most recent d average amplitude values, where d <ROW。

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