Frequency agility method and device based on broadband detection and reception

Abstract

The invention belongs to the field of radar frequency domain anti-interference, and relates to a frequency agility method and device based on broadband detection and reception, and the method comprises the steps: S1, determining a frame task type of a previous frame of a radar; s2, when the frame task type of the previous frame is a frame receiving task, executing a normal frame task, and otherwise, executing the frame receiving task; s3, calculating the data obtained through the frame receiving task to obtain a broadband signal power spectrum; step S4, when the coverage range of the detection frame monitoring signal is matched, determining the amplitude sampling point range of the broadband signal power frequency spectrum corresponding to each frequency point of radar working so as to calculate the average amplitude of each frequency point; step S5, calculating an average value of a plurality of average amplitudes subjected to recent statistics, and selecting frequency points corresponding to a plurality of smaller average values as screening frequency points; and S6, executing frequency point agility of a normal frame task from a random frequency point in the screened frequency points. According to the invention, the adaptive anti-interference capability of the radar in a complex electromagnetic environment is improved.

Description

Technical Field

[0001] The present application belongs to the field of radar frequency domain anti-interference, and in particular relates to a frequency agile method and device based on broadband detection. Background Art

[0002] With the continuous advancement of modern radar electronic countermeasure technology, the confrontation between interference and anti-interference has become increasingly fierce. Faced with an increasingly complex electromagnetic environment, radars urgently need to improve their anti-interference capabilities and reduce the impact of interference on radar detection and tracking of valuable targets in order to play a normal combat role in modern warfare. Frequency domain anti-interference technology is an important area of ​​radar anti-interference measures. Frequency domain anti-interference measures mainly include radar working frequency domain expansion, frequency agility, frequency diversity, adaptive frequency agility, etc.

[0003] Frequency agility, as the main measure of frequency domain anti-interference, has a strong ability to resist active suppression interference and is also a commonly used anti-interference technology for airborne radars. Traditional frequency agility only makes regular or irregular changes within a certain frequency domain, without considering changes in the radar's working electromagnetic environment, and is not effective in resisting predictive targeted interference and distributed interference. From the perspective of radar target detection, the radar has an optimal operating frequency for a specific electromagnetic environment. By eliminating interference frequencies in real time through broadband detection, the radar can automatically track the optimal operating frequency, which provides a technical direction for airborne radars to adapt to complex electromagnetic field environments, resist targeted interference and distributed interference, and rationally utilize spectrum resources. Summary of the invention

[0004] In order to solve the above problems, the present application provides a frequency agility method and device based on broadband detection, so as to adaptively extract the frequency band area with the weakest interference and screen out the corresponding frequency points to complete radar frequency agility.

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

[0006] Step S1, determining the frame task type of the previous frame of the radar, wherein the frame task type includes a frame receiving task and a normal frame task;

[0007] Step S2: when the frame task type of the previous frame is a frame receiving task, go to step S6 to execute a normal frame task; when the frame task type of the previous frame is a normal frame task, go to step S3 to execute a frame receiving task;

[0008] Step S3, calculating the broadband signal power spectrum based on the data acquired through the frame receiving task;

[0009] Step S4: for each frequency point of the radar operation, when its frequency coverage range completely falls within the coverage range of a detection frame monitoring signal, determine the amplitude sampling point range of the broadband signal power spectrum corresponding to the frequency point to calculate the average amplitude;

[0010] Step S5: for each frequency point, calculate the average value of the average amplitude of the Row times of the most recently executed frame receiving task, and select the frequency points corresponding to the smaller average values ​​as the screening frequency points returned by the frame receiving task;

[0011] Step S6: Randomly select a frequency point from the screening 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 agilely change to the random frequency point.

[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, where T monitor The period of the frame detection task is configured in advance to be shorter than the shortest period of the normal frame task;

[0014] Step S22: determine the frame interrupt signal interval between the current frame and the previous frame. If it is less than the determination parameter T INR , the frame task type of the previous frame is determined to be a frame receiving task, and the current frame executes a normal frame task; otherwise, the current frame executes a frame receiving task.

[0015] Preferably, step S3 further comprises:

[0016] Step S31, unpacking the data obtained through the frame receiving task to obtain the original pulse sampling data of multiple sampling points of IQ two channels;

[0017] Step S32, performing a DC removal operation on the original pulse sampling data of the IQ channels, and then performing vector combination;

[0018] Step S33: performing time-frequency conversion on the vector combined data to obtain a single pulse broadband signal power spectrum.

[0019] Preferably, step S4 further comprises:

[0020] Step S41, calculate the number F i The frequency point corresponds to the middle sampling point K in the broadband signal power spectrum P(k) i :

[0021]

[0022] Among them, f0 is the radar working starting frequency, Fi is the number of the i-th frequency point, B freq is the frequency interval, f low is the lower limit of the signal monitoring coverage range 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: Sampling the number of points N according to the amplitude of a single frequency point gap Calculate the average amplitude P corresponding to the frequency point * (i)

[0024]

[0025] Preferably, before step S5, the method further comprises:

[0026] Step S51: remove the frequency points corresponding to the higher average values ​​of the average amplitudes of the most recent d times, where d <ROW。

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

[0028] A frame task type determination module is used to determine the frame task type of the radar frame, wherein the frame task type includes a frame receiving task and a normal frame task;

[0029] An alternating control module, used for executing a normal frame task when the frame task type of the previous frame is a frame receiving task, and executing a frame receiving task when the frame task type of the previous frame is a normal frame task;

[0030] A broadband signal power spectrum calculation module is used to calculate the broadband signal power spectrum from the data obtained through the frame receiving task;

[0031] 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 the radar operation when its frequency coverage range completely falls within the coverage range of a detection frame monitoring signal, so as to calculate the average amplitude;

[0032] The frequency point screening module is used to calculate the average value of the average amplitude of the Row of the most recent frame receiving task for each frequency point, and select the frequency points corresponding to the smaller average values ​​as the screening frequency points returned by the frame receiving task;

[0033] The frequency agility module is used to 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 agilely change to the random frequency point.

[0034] Preferably, the alternating control module comprises:

[0035] A determination parameter acquisition unit, used to obtain a determination parameter T of a frame task type. INR :T INR =T monitor +1, where T monitor The period of the frame detection task is configured in advance to be shorter than the shortest period of the normal frame task;

[0036] The signal interval comparison unit is used to determine the frame interrupt signal interval between the current frame and the previous frame. If it is less than the judgment parameter T INR , the frame task type of the previous frame is determined to be a frame receiving task, and the current frame executes a normal frame task; otherwise, the current frame executes a frame receiving task.

[0037] Preferably, the broadband signal power spectrum calculation module includes:

[0038] The unpacking unit is used to unpack the data obtained through the frame receiving task to obtain the original pulse sampling data of multiple sampling points of IQ two channels;

[0039] A DC removal unit is used to remove the DC from the original pulse sampling data of the IQ channels and then perform vector combination;

[0040] The time-frequency conversion unit is used to perform time-frequency conversion on the data after vector combination to obtain the power spectrum of the single pulse broadband signal.

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

[0042] The frequency domain intermediate sampling point calculation unit is used to calculate the number F i The frequency point corresponds to the middle sampling point K in the broadband signal power spectrum P(k) i :

[0043]

[0044] Among them, f0 is the radar working starting frequency, F i is the number of the i-th frequency point, B freq is the frequency interval, f low is the lower limit of the signal monitoring coverage range 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;

[0045] The average amplitude calculation unit is used to calculate the number of sampling points N according to the amplitude of a single frequency point. gap Calculate the average amplitude P corresponding to the frequency point * (i)

[0046]

[0047] Preferably, the frequency agility module includes:

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

[0049] This application improves the adaptive anti-interference capability of radar in complex electromagnetic environments. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0051] Figure 2 This is the broadband receiving frequency coverage map.

[0052] Figure 3 This is the spectrum accumulation result of the broadband detection frame.

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

[0054] Figure 5 Schematic diagram of frequency agility anti-interference effect. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the implementation of this application will be described in more detail in combination with the drawings in the implementation of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described implementation is a part of the implementation of this application, not all of the implementations. The implementation described below with reference to the drawings is exemplary and is intended to be used to explain this application, and cannot be understood as a limitation on this application. Based on the implementation in this application, all other implementations obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The implementation of this application is described in detail below in combination with the drawings.

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

[0057] Step S1, determining the frame task type of the previous frame of the radar, wherein the frame task type includes a frame receiving task and a normal frame task;

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

[0059] Step S3, calculating the broadband signal power spectrum based on the data acquired through the frame receiving task;

[0060] Step S4: for each frequency point of the radar operation, when its frequency coverage range completely falls within the coverage range of a detection frame monitoring signal, determine the amplitude sampling point range of the broadband 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 average amplitude of the Row times of the most recently executed frame receiving task, and select the frequency points corresponding to the smaller average values ​​as the screening frequency points returned by the frame receiving task;

[0062] Step S6: Randomly select a frequency point from the screening 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 agilely change to the random frequency point.

[0063] The present application eliminates interference frequencies in real time through broadband detection and reception, and realizes automatic tracking of the optimal operating frequency by the radar. Specifically, in step S1 and step S2, frame reception and normal frame operation are performed alternately. In step S3-step S5, frame reception is used to realize electromagnetic environment monitoring, complete real-time sampling, processing, and analysis of the external working electromagnetic environment, adaptively extract the frequency band area with the weakest interference and screen out the corresponding frequency points, and provide a spectrum basis for adaptive frequency agility. In step S6, the normal frame is used to perform normal search tasks, and a frequency point is randomly selected from the frequency point pool composed of the screened corresponding frequency points to complete frequency agility, thereby realizing frequency agility and anti-interference.

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

[0065] (1) Wideband detection frame monitoring covers frequency bandwidth B monitor The design of broadband detection frame signal parameters is determined by the broadband detection coverage frequency bandwidth. Based on the consideration of completing the statistics of interference in the radar working frequency band in the shortest time, the maximum working bandwidth of the radar receiver is used as the broadband detection frame monitoring coverage frequency bandwidth B. monitor , in Hertz. According to the Nyquist sampling theorem, the sampling rate of the broadband detection frame signal is ω monitor , in Hertz, must satisfy B monitor <ω monitor At the same time, it is necessary to design the broadband detection frame signal frequency F monitor ,Since the signal time domain sampling is the periodic extension of the spectrum, F monitor It needs to be the center frequency of the broadband detection coverage frequency. Based on the above parameters, the detection frequency point F required to complete the statistics of the interference situation of the radar working frequency band can be calculated. monitor [N monitor ],N monitorIndicates the total number of broadband receiving frequencies, 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 operating frequency band, FB l Indicates the lower limit of the radar operating frequency band. monitor The detection coverage of [0] is [FB l ,F monitor [0]+B monitor / 2],F monitor The detection coverage of [1] is [F monitor [1]-B monitor / 2,F monitor [1]+B monitor / 2], and so on, F monitor [N monitor ]'s detection coverage is [F monitor [N monitor ]-B monitor / 2,FB h ]. For example, radar operating frequency band B radar The designed detection frame monitoring covers the frequency bandwidth B monitor If the frequency band is 200MHz, a total of 4 detection frequency points F need to be designed. monitor [0]-F monitor [3] can cover this, where F monitor [0] covers a range of 0-200MHz with a center frequency of 100MHz. Here, F monitor [0] = 100MHz. Similarly, F monitor [1] = 300MHz, F monitor [2] = 500MHz, F monitor [3] = 700MHz.

[0066] (2) Pulse repetition period PRI of broadband detection frame signal monitor , in milliseconds, the number of pulses in the broadband detection frame is M, then the corresponding frame period of the broadband detection frame is T monitor =PRI monitor ×M, in milliseconds, to prevent broadband detection frames from affecting normal search frame work and signal processing, T monitor It should be as short as possible as possible as short as possible normal , which is the key parameter for step S2 to determine whether the previous frame is a normal frame task or a frame receiving task.

[0067] Secondly, the number of broadband detection frame pulse sampling points is N, N = PRI monitor ×ω monitor Since the spectrum obtained by Fourier transform (FFT) after sampling the broadband signal is a discrete spectrum, the interval between the signal spectra is the spectrum resolution ΔB, which is expressed in Hertz. Then ΔB = ω monitor / N; In order to detect the frequency signal of the normal search frame in real time, the spectrum resolution ΔB of the broadband detection frame needs to be smaller than the normal search frame signal bandwidth B normal , that is, ΔB normal Therefore, when setting the pulse repetition period of the broadband detection frame, it is necessary to meet the following conditions: 1 / PRI monitor normal .

[0068] In addition, PRI monitor The larger the pulse sampling point number N is, the better the spectrum resolution ΔB is. However, the larger N is, the longer the broadband detection frame period T is. monitor The larger the value, the longer the signal processing time will be, and the greater the impact on the normal search operation of the radar. Therefore, the pulse repetition period PRI of the broadband detection frame monitor The setting should avoid PRI while ensuring the spectrum resolution. monitor If it is too large, it will affect the normal search operation of the radar.

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

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

[0071] Step S21, obtaining the determination parameter T of the frame task type INR :T INR =T monitor +1, where T monitor The period of the frame detection task is configured in advance to be shorter than the shortest period of the normal frame task;

[0072] Step S22: determine the frame interrupt signal interval between the current frame and the previous frame. If it is less than the determination parameter T INR , the frame task type of the previous frame is determined to be a frame receiving task, and the current frame executes a normal frame task; otherwise, the current frame executes a frame receiving task.

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

[0074] Step S3 starts to execute the frame receiving task, which sets the radar frame receiving working parameters, executes steps S3 to S5, and sends the radar normal working parameter information set by the previous normal frame task to the radar system, such as channel information, normal frame frequency information, etc. In order to accurately monitor external environmental interference, the antenna unit should maintain a passive receiving mode when performing the detection and reception task. In order to avoid introducing channel consistency errors, the same channel and the same channel gain should be maintained during the detection and reception frame task to complete the broadband signal sampling, that is, the RF unit maintains a broadband single-channel receiving mode.

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

[0076] Step S31, unpacking the data obtained through the frame receiving task to obtain the original pulse sampling data of multiple sampling points of IQ two channels;

[0077] Step S32, performing a DC removal operation on the original pulse sampling data of the IQ channels, and then performing vector combination;

[0078] Step S33: performing time-frequency conversion on the vector combined data to obtain a single pulse broadband signal power spectrum.

[0079] In this embodiment, during the broadband detection frame operation, the signal processing completes the aforementioned M pulses of broadband signal A / D sampling pulse sequence data X0, X1, X2. m ,…,X M-1 After the broadband detection frame completes the last A / D sampling pulse sequence data cache, it is unpacked. In step S31, the original pulse sampling data x of N sampling points in the IQ two channels is obtained. I (m,n) and x Q (m,n), where x I (m,n) represents the I-channel data of the n-th sampling point of the m-th pulse, x Q (m,n) represents the Q data of the nth sampling point of the mth pulse. Then in step S32, the IQ data is de-DCed by the following formula to stabilize the signal and obtain the IQ data after de-DCing: and

[0080]

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

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

[0083] X(m,k)=FFT(x(m,n)),0≤k≤N-1;

[0084] Secondly, convert the spectrum result of the X(m,k) signal into a power value result P(m,k), that is, P(m,k) = |X(m,k)|; where k is the sampling point in the frequency domain. Finally, add the power value results P(m,k) of the above m pulses according to the value of k to form a spectrum accumulation result P(k), that is, P(k) = P(0,k) + P(1,k) + ... + P(m-1,k). The spectrum accumulation result is referenced Figure 3 As shown, that is Figure 3 In , each discrete k value (abscissa) corresponds to a broadband signal power spectrum P(k).

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

[0086] Frequency matching mainly calculates the range of each frequency point, where F i Indicates the sequence number of the i-th frequency point, Figure 4 40 frequency points are given, and the frequency points are numbered 1-40, which is different from the frame-by-frame detection frequency point F. monitor [N monitor ], where 40 frequency points are narrowband, and the frequency point of frame receiving frame is wideband. Therefore, this step is mainly to determine which wideband these narrowbands fall into. The signal monitoring coverage of frame receiving frame has been given before. Of course, the frequency point number F of frame receiving frame can also be used. monitorx Quick calculation, i.e. the lower limit of the monitoring range f low =f0+F monitorx *B freq -B monitor / 2; upper limit of monitoring range f high =f0+F monitorx *B freq +B monitor / 2; where the radar operating starting frequency f0 is the frequency of the radar operating frequency point 0 (or Figure 4 Frequency point 1 in B freq The coverage of the 40 frequency points of the narrowband is calculated in the same way, using the serial number F of each frequency point. i And frequency interval B freq , Normal frame signal bandwidth B normal Calculate and obtain:

[0087]

[0088] Then, for each frequency point where the radar works, determine its frequency coverage range Whether it is completely within the coverage of a detection frame monitoring signal [f low ,f high ], for example, if the current frequency F i Satisfy at the same time

[0089]

[0090] This indicates that the frequency point is within the coverage range of the received signal and F i ≠F normal Calculate the power mean when Figure 3 It is expressed in the form of amplitude, so this can also be called the calculated average amplitude.

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

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

[0093]

[0094] Among them, f0 is the radar working starting frequency, F i is the number of the i-th frequency point, B freq is the frequency interval, f low is the lower limit of the signal monitoring coverage range 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;

[0095] Step S42: Sampling the number of points N according to the amplitude of a single frequency point gap Calculate the average amplitude P corresponding to the frequency point * (i)

[0096]

[0097] In this embodiment, each frequency point is numbered Fi Corresponding to an average amplitude P * (i) If the frequency coverage does not meet the above conditions or the current calculated frequency is equal to the frequency of the previous normal search frame, that is, F i =F normal , then the frequency point number F i The corresponding average amplitude P * (i) is 0.

[0098] By the single average amplitude P * (i) Size is not a good basis for frequency selection. Therefore, in step S5, the present application counts the average amplitudes of the most recent frame collection tasks and uses the average value of these average amplitudes as a basis for frequency selection.

[0099] In order to count the statistical results of all frame collection tasks, the program can design a variable T(i) to track the frequency point number F of each frame collection task. i The corresponding average amplitude P * (i), that is, when the average amplitude P * When (i) is not 0, the variable T(i) of the frame receiving task is 1, otherwise it is 0. In this way, the average amplitude P of the frame receiving task of the row can be accumulated. * (i), and then divide it by the accumulated T(i) to calculate the average value of the average amplitude. Here Row is usually 100. When the program is initially executed and there are not 100 data, the number of data is calculated.

[0100] Figure 4 The average value of the average amplitude of each frequency point of 40 frequency points is given in , 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 detection frame task, such as Figure 4 In the process, 5 frequency points are selected from 40 statistical frequency points as screening frequency points and added to the frame reception screening frequency point pool. The frame reception screening frequency point pool is used for the subsequent step S6 to perform the normal frame task. When the program has not yet executed step S5, multiple frequency points can be selected from all frequency points at equal intervals to fill in the frame reception screening frequency point pool.

[0101] In some optional implementations, before step S5, the method further includes:

[0102] Step S51: remove the frequency points corresponding to the higher average values ​​of the average amplitudes of the most recent d times, where d <ROW。

[0103] In this embodiment, in order to avoid the influence of the frequency points with abnormal amplitude in the latest broadband detection on the statistical results, referring to the above steps, the results of the latest d-frame detection are statistically calculated to have an average value, where d is usually taken as 2, that is, step S5 calculates the average value of the average amplitude of the first 100 times, and selects the low value therefrom, and this embodiment calculates the average value of the average amplitude of the first 2 times in the same way, selects the high value therefrom, and does not perform the low value selection operation of step S5. Assuming that three high-value frequency points 35, 36, and 37 are selected, then in program design, the amplitudes of these three frequency points can be set to the maximum value, so that when the low value is selected in the subsequent step S5, these three frequency points will not be selected. In addition, the radar training frequency point and the previous normal search frame working frequency point can also be eliminated, that is, the amplitudes of the training frequency point and the normal search frame frequency point are set to the maximum value.

[0104] After completing the frame collection task, return to Figure 1 In step S6, the normal frame task saves the frequency point F of the previous normal frame. normal , randomly select a frequency F from the detection and screening frequency pool temp , judge F temp Is it the current normal search frame frequency? If any of the following two conditions are met, the frequency of the current normal frame is updated to F temp :

[0105] (1)F temp ≠F normal ;

[0106] (2) The number of executions of randomly selecting a frequency point from the detection and screening frequency point pool is greater than the maximum number of executions within one frame.

[0107] By the above method, the frequency F is determined temp As one of the frequencies least affected by interference, the radar operating frequency continuously changes to the frequency with the least interference impact to perform target detection and tracking tasks, achieving frequency agility and anti-interference.

[0108] Figure 5 The anti-interference effect diagram is given. After the interference is injected into the 23rd frequency point, the radar automatically changes its working frequency point agility range from the 20th to the 25th frequency point to the 28th to the 33rd frequency point when performing normal search and tracking tasks, effectively avoiding the interfered frequency band. The results show that this application realizes the interference frequency elimination and frequency agility method based on broadband detection.

[0109] This application has the following advantages:

[0110] 1. Rationally and effectively utilize radar broadband signal resources, adopt radar broadband single-channel mode to realize broadband electromagnetic environment monitoring function, and record broadband spectrum data in real time;

[0111] 2. Based on the broadband electromagnetic environment detection results, the interference frequency points are eliminated, and several candidate frequency points with less interference are selected to form a screening frequency point pool. When the radar performs normal search and tracking tasks, the frequency points are randomly selected from the screening frequency point pool to achieve frequency agility, which can effectively counter cross-frequency active deception interference, direct-type and sweep-type narrow-band aiming suppression interference;

[0112] 3. The broadband signal detection frame and the radar normal search and tracking frame are alternately polled to achieve real-time update of the interference situation of the radar working frequency band, which improves the radar's adaptive anti-interference ability in complex electromagnetic environments without affecting the normal search and tracking work of the radar;

[0113] 4. The use of adaptive interference frequency elimination and frequency agile anti-interference technology enables the radar to achieve more targeted interference frequency band avoidance and improve the radar's target search and tracking performance.

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

[0115] A frame task type determination module is used to determine the frame task type of the radar frame, wherein the frame task type includes a frame receiving task and a normal frame task;

[0116] An alternating control module, used for executing a normal frame task when the frame task type of the previous frame is a frame receiving task, and executing a frame receiving task when the frame task type of the previous frame is a normal frame task;

[0117] A broadband signal power spectrum calculation module is used to calculate the broadband signal power spectrum from the data obtained through the frame receiving task;

[0118] 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 the radar operation when its frequency coverage range completely falls within the coverage range of a detection frame monitoring signal, so as to calculate the average amplitude;

[0119] The frequency point screening module is used to calculate the average value of the average amplitude of the Row of the most recent frame receiving task for each frequency point, and select the frequency points corresponding to the smaller average values ​​as the screening frequency points returned by the frame receiving task;

[0120] The frequency agility module is used to 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 agilely change to the random frequency point.

[0121] In some optional implementations, the alternating control module includes:

[0122] A determination parameter acquisition unit, used to obtain a determination parameter T of a frame task type.INR :T INR =T monitor +1, where T monitor The period of the frame detection task is configured in advance to be shorter than the shortest period of the normal frame task;

[0123] The signal interval comparison unit is used to determine the frame interrupt signal interval between the current frame and the previous frame. If it is less than the judgment parameter T INR , the frame task type of the previous frame is determined to be a frame receiving task, and the current frame executes a normal frame task; otherwise, the current frame executes a frame receiving task.

[0124] In some optional implementations, the broadband signal power spectrum calculation module includes:

[0125] The unpacking unit is used to unpack the data obtained through the frame receiving task to obtain the original pulse sampling data of multiple sampling points of IQ two channels;

[0126] A DC removal unit is used to remove the DC from the original pulse sampling data of the IQ channels and then perform vector combination;

[0127] The time-frequency conversion unit is used to perform time-frequency conversion on the data after vector combination to obtain the power spectrum of the single pulse broadband signal.

[0128] In some optional implementations, the average amplitude calculation module includes:

[0129] The frequency domain intermediate sampling point calculation unit is used to calculate the number F i The frequency point corresponds to the middle sampling point K in the broadband signal power spectrum P(k) i :

[0130]

[0131] Among them, f0 is the radar working starting frequency, F i is the number of the i-th frequency point, B freq is the frequency interval, f low is the lower limit of the signal monitoring coverage range 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;

[0132] The average amplitude calculation unit is used to calculate the number of sampling points N according to the amplitude of a single frequency point. gap Calculate the average amplitude P corresponding to the frequency point * (i)

[0133]

[0134] In some optional implementations, the frequency agility module includes:

[0135] The frequency point elimination unit is used to eliminate the frequency points corresponding to the higher average values ​​of the average amplitudes of the most recent d times, where d <ROW。

[0136] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A frequency agility method based on broadband detection, characterized in that: include: Step S1, determining the frame task type of the previous frame of the radar, wherein the frame task type includes a frame receiving task and a normal frame task; Step S2: when the frame task type of the previous frame is a frame receiving task, go to step S6 to execute a normal frame task; when the frame task type of the previous frame is a normal frame task, go to step S3 to execute a frame receiving task; Step S3, calculating the broadband signal power spectrum based on the data acquired through the frame receiving task; Step S4: for each frequency point of the radar operation, when its frequency coverage range completely falls within the coverage range of a detection frame monitoring signal, determine the amplitude sampling point range of the broadband signal power spectrum corresponding to the frequency point to calculate the average amplitude; Step S5: for each frequency point, calculate the average value of the average amplitude of the Row times of the most recently executed frame receiving task, and select the frequency points corresponding to the smaller average values ​​as the screening frequency points returned by the frame receiving task; Step S6: Randomly select a frequency point from the screening 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 agilely change to the random frequency point.

2. The frequency agility method based on broadband detection as claimed in claim 1, characterized in that: Step S2 further comprises: Step S21, obtaining the determination parameter T of the frame task type INR :T INR =T monitor +1, where T monitor The period of the frame detection task is configured in advance to be shorter than the shortest period of the normal frame task; Step S22: determine the frame interrupt signal interval between the current frame and the previous frame. If it is less than the determination parameter T INR , the frame task type of the previous frame is determined to be a frame receiving task, and the current frame executes a normal frame task; otherwise, the current frame executes a frame receiving task.

3. The frequency agility method based on broadband detection as claimed in claim 1, characterized in that: Step S3 further comprises: Step S31, unpacking the data obtained through the frame receiving task to obtain the original pulse sampling data of multiple sampling points of IQ two channels; Step S32, performing a DC removal operation on the original pulse sampling data of the IQ channels, and then performing vector combination; Step S33: performing time-frequency conversion on the vector combined data to obtain a single pulse broadband signal power spectrum.

4. The frequency agility method based on broadband detection as claimed in claim 1, characterized in that: Step S4 further comprises: Step S41, calculate the number F i The frequency point corresponds to the middle sampling point K in the broadband signal power spectrum P(k) i : Among them, f0 is the radar working starting frequency, F i is the number of the i-th frequency point, B freq is the frequency interval, f low is the lower limit of the signal monitoring coverage range 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; Step S42: Sampling the number of points N according to the amplitude of a single frequency point gap Calculate the average amplitude P corresponding to the frequency point * (i) 5. The frequency agility method based on broadband detection as claimed in claim 1, characterized in that: Before step S5, the method further comprises: Step S51: remove the frequency points corresponding to the higher average values ​​of the average amplitudes of the most recent d times, where d <ROW。 6. A frequency agile device based on broadband detection, characterized in that: include: A frame task type determination module is used to determine the frame task type of the radar frame, wherein the frame task type includes a frame receiving task and a normal frame task; An alternating control module, used for executing a normal frame task when the frame task type of the previous frame is a frame receiving task, and executing a frame receiving task when the frame task type of the previous frame is a normal frame task; A broadband signal power spectrum calculation module is used to calculate the broadband signal power spectrum from the data obtained through the frame receiving 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 the radar operation when its frequency coverage range completely falls within the coverage range of a detection frame monitoring signal, so as to calculate the average amplitude; The frequency point screening module is used to calculate the average value of the average amplitude of the Row of the most recent frame receiving task for each frequency point, and select the frequency points corresponding to the smaller average values ​​as the screening frequency points returned by the frame receiving 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 when executing the normal frame task, control the working frequency point of the normal frame to agilely change to the random frequency point.

7. The frequency agile device based on broadband detection as claimed in claim 6, characterized in that: The alternating control module comprises: A determination parameter acquisition unit, used to obtain a determination parameter T of a frame task type. INR :T INR =T monitor +1, where T monitor The period of the frame detection task is configured in advance to be shorter than the shortest period of the normal frame task; The signal interval comparison unit is used to determine the frame interrupt signal interval between the current frame and the previous frame. If it is less than the judgment parameter T INR , the frame task type of the previous frame is determined to be a frame receiving task, and the current frame executes a normal frame task; otherwise, the current frame executes a frame receiving task.

8. The frequency agile device based on broadband detection as claimed in claim 6, characterized in that: The broadband signal power spectrum calculation module includes: The unpacking unit is used to unpack the data obtained through the frame receiving task to obtain the original pulse sampling data of multiple sampling points of IQ two channels; A DC removal unit is used to remove the DC from the original pulse sampling data of the IQ 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 the single pulse broadband signal.

9. The frequency agile device based on broadband detection as claimed in claim 6, characterized in that: The average amplitude calculation module comprises: The frequency domain intermediate sampling point calculation unit is used to calculate the number F i The frequency point corresponds to the middle sampling point K in the broadband signal power spectrum P(k) i : Among them, f0 is the radar working starting frequency, F i is the number of the i-th frequency point, B freq is the frequency interval, f low is the lower limit of the signal monitoring coverage range 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; The average amplitude calculation unit is used to calculate the number of sampling points N according to the amplitude of a single frequency point. gap Calculate the average amplitude P corresponding to the frequency point * (i) 10. The frequency agile device based on broadband detection as claimed in claim 6, characterized in that: The frequency agility module comprises: The frequency point elimination unit is used to eliminate the frequency points corresponding to the higher average values ​​of the average amplitudes of the most recent d times, where d <ROW。

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