A method for combining and sorting pulses of multiple radiation sources

Abstract

The present invention belongs to the field of radar target signal generation and simulation, and mainly relates to a sorting method for the combined output pulse signals of multiple radiation sources. The method includes the following steps: setting the multi-source radar signal environment scene parameters; generating a combined pulse train by sequentially changing the pulse arrival time of each path signal, seeking the optimal combined output effect after optimization and selection, and recording the pulse delay data of each path; sorting according to this data to generate a high-density pulse description word sequence. The combined signal pulses generated by the present invention have a compact pulse distribution, can maximize the use of the idle time of each branch signal, thereby improving the pulse overlap phenomenon and increasing the number of combined output pulses.

Description

Technical Field

[0001] The invention belongs to the field of radar target signal generation and simulation, and mainly relates to a method for sequencing pulse signals output by combining multiple radiation sources. Background Art

[0002] When testing the functions of airborne radar warning equipment on the ground, a dense electromagnetic environment must be constructed first. With the rapid development of computer simulation technology in recent years, more research tends to use software programming to fuse multiple radar signals into a high-density pulse description word sequence. Based on this sequence, only one radar signal simulator is needed to simulate multi-source signals. However, in the above process, it is very likely that multiple radar signals will overlap in time. Excessive overlap will cause some pulses to be lost or parameters to change, making it impossible for the warning equipment to quickly and effectively sort and identify electromagnetic signals. Therefore, how to effectively deal with the overlap phenomenon in pulse sorting is an issue that needs to be studied urgently in the process of using computer simulation to construct a dense electromagnetic environment. Summary of the invention

[0003] In view of this, the present invention, based on the analysis of the existing multiple radar signal sorting methods, designs a new pulse sorting algorithm to reduce the probability of pulse overlap as much as possible, retain pulse integrity, make the constructed electromagnetic environment denser, and enable the equipment to more quickly and accurately complete the sorting and identification of radiation sources, ultimately improving the reliability of radar warning equipment detection.

[0004] To achieve the above object, the technical solution of the present invention is to design a multi-radiation source combined pulse sequencing method, which is characterized by comprising:

[0005] Step S1, according to the given multi-radiation source signal parameters, the pulse arrival time of each signal is changed in turn to generate a combined signal sequence, the optimal output effect is sought, and the pulse delay data of each signal is recorded;

[0006] Step S2, sorting the pulse delay data of each channel corresponding to the optimal output effect to generate a high-density pulse description word sequence.

[0007] The signal parameters described in step S1 should include the pulse width, pulse repetition interval (PRI), pulse amplitude, and carrier frequency of the radar radiation signal of each part, and the above parameter values ​​of each signal are constant during the sorting process.

[0008] The generating of the combined signal sequence in step S1 includes the following contents:

[0009] Step S11, firstly, according to the multiple signals provided by the scene, one channel is selected as the reference sequence, and the sequence will not be delayed; then, the signal sequence with the largest PRI is selected from the multiple signals, and its PRI is set to p m, starting from time 0, intercept n m pulse repetition intervals, then the sequence length L can be expressed as:

[0010] L = p m *n m

[0011] The lengths of the remaining sequences are all L. Then the number of pulses n k contained in the signal sequence with serial number k is:

[0012] n k = INT(L / p k )

[0013] where p k represents the PRI value of the signal sequence with serial number k, and satisfies p k ≤ p m ; INT represents the integer operation.

[0014] Step S12, construct a multi-source signal sequence array with a dimension of 3, denoted by dlist[k, t, j]. The meanings of each dimension are as follows:

[0015] k: radar serial number, 0 ≤ k < rnum, where rnum is the number of radars;

[0016] t: signal delay, in units of 1 μs. Assume the PRI of the reference sequence is p 0 , using the periodicity of the pulse signal, the delay range of the remaining sequences only needs to generate a delay length of one repetition period relative to the reference signal to include the optimal combining effect, that is, 0 ≤ t < p 0 ;

[0017] j: discrete time point in the signal sequence, in units of 1 μs, 0 ≤ j < L.

[0018] Step S13, perform triple traversal with k, t, and j as variables to obtain the temporary combined signal sequence plist[j]:

[0019]

[0020] In the above formula, the summation symbol represents the corresponding addition of array elements. Therefore, the length of plist[j] is also L; since there is a pulse overlap phenomenon at this time, plist[j] does not represent the final combined output result, but only serves as an important criterion for pulse optimization and selection.

[0021] Step S14, taking the radar of the current transmitted signal as the main line, perform pulse optimization and selection to obtain the effective combined sequence alist.

[0022] Step S15: Set a reference value maxt with an initial value of 0. Calculate the number of combined output pulses or duty cycle n when the current delay of each path is τ[k]. If n > maxt, then maxt = n, and record the delay τ[k] of each path at this time.

[0023] The pulse optimization and selection described in step S14 are specifically as follows:

[0024] (1) In the initial state, the radar serial number lsa of the transmitted signal is 0;

[0025] (2) Set i as the loop variable, satisfying (for i = 0; i < L; i++);

[0026] (3) When plist[i] = 0 and plist[i + 1]!= 0, the new pulse transmission condition is satisfied. Record the radar serial number k at this time, then lsa = k;

[0027] (4) When the new pulse transmission condition described in (3) is not satisfied, if there exists plist[i]!= 0 and plist[i + 1]!= 0 and plist[i + 1]!= plist[i] and dlist[lsa][t][i + 1] = 0, that is, the combined sequence value is not zero and changes; if dlist[lsa][t][i + 1] = 0 is also satisfied at the same time, that is, this change occurs at the trailing edge of the current reserved pulse sequence, then retain this pulse, and record the radar serial number k corresponding to this pulse, then lsa = k;

[0028] The generation of the combined signal sequence described in step S1 can adopt multi-threaded operation: when designing the program, change the core time-consuming operations to multi-threaded parallel operation. Each thread occupies an independent CPU core, and the operations do not interfere with each other. And during the operation process, the operator can still operate the software main interface to perform other tasks.

[0029] The pulse descriptor described in step S2 should include the pulse arrival time, pulse width, pulse repetition interval, pulse amplitude, and carrier frequency of each pulse; combined with the message header and message tail, this pulse descriptor can be used as a message for real-time FPGA calculation; all parameters are encoded in hexadecimal. Among them, the contents of the message header and message tail are fixed, and the remaining data are generated according to the principle of low data bits first and high data bits later. Based on the above rules, the combined output pulse sequence can be converted into a PDW sequence file for hardware reading. Description of the Drawings

[0030] Figure 1 is the overall flowchart of a multi-radiation source combined pulse sorting method of the present invention.

[0031] Figure 2 is the selection scheme diagram of a multi-radiation source combined pulse sorting method of the present invention when pulses overlap.

[0032] Figure 3 It is the combined output waveform diagram after sorting by a multi-radiation source combined pulse sorting method of the present invention.

[0033] Figure 4 It is the pulse description word sequence diagram generated by a multi-radiation source combined pulse sorting method of the present invention. Detailed implementation manners

[0034] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the implementation manners of this application will be described in more detail below in conjunction with the accompanying drawings in the implementation manners of this application. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions from beginning to end. The described implementation manners are part of the implementation manners of this application, rather than all of the implementation manners. The implementation manners described below by referring to the drawings are exemplary and are intended to explain this application and should not be construed as a limitation of this application. Based on the implementation manners of this application, all other implementation manners obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application. The implementation manners of this application will be described in detail below in conjunction with the drawings.

[0035] Combined with the attached Figure 1 , the technical solution of the present invention is to design a multi-radiation source combined pulse sorting method, including the following steps:

[0036] Step S1, according to the given multi-radiation source signal parameters, delay the pulse arrival time of each path of signals in turn to generate a combined signal, seek the optimal output effect, and record the pulse delay data of each path;

[0037] Step S2, sort according to the pulse delay data of each path corresponding to the optimal output effect to generate a high-density pulse description word sequence.

[0038] Further, the signal parameters described in step S1 should include pulse width, pulse repetition interval, pulse amplitude, and carrier frequency. Since the present invention focuses on the research of pulse sorting algorithms, conventional pulse signals with relatively simple forms are selected.

[0039] Further, the generation of the combined signal described in step S1 includes the following content:

[0040] Step S11, first, according to the multiple paths of signals provided by the scenario, arbitrarily select one path as the reference sequence, and this sequence will not be delayed. Then select the signal sequence with the largest PRI from the multiple paths of signals, and make its PRI be p m , starting from the 0 moment, intercept n m pulse repetition intervals, then the sequence length L can be expressed as:

[0041] L = p m *n m

[0042] For the remaining sequences, each has a length of L. Then the number of pulses n contained in the signal sequence with serial number k is k as follows:

[0043] n k = INT(L / p k )

[0044] where p k represents the PRI value of the signal sequence with serial number k, and satisfies p k ≤ p m ; INT represents the integer operation.

[0045] Step S12: Construct the signal sequence array from the transmitted signal parameters of multiple radars in the scenario setting, including carrier frequency, pulse width, pulse repetition interval, amplitude, etc. The array dimension is 3, denoted by dlist[k, t, j]. The meanings of each dimension are as follows:

[0046] k: Radar serial number, 0 ≤ k < rnum, where rnum is the number of radars;

[0047] t: Signal delay, with the unit of 1 μs. Assume the PRI of the reference sequence is p 0 . Using the periodicity of the pulse signal, the delay range of the remaining sequences only needs to generate a delay length of one repetition period relative to the reference signal to include the optimal combining effect, that is, 0 ≤ t < p 0 .

[0048] j: Discrete time point in the signal sequence, with the unit of 1 μs, 0 ≤ j < L.

[0049] So far, the pulse delay array is constructed, which contains all possible delays of each signal relative to the reference signal.

[0050] Step S13: Perform triple traversal with k, t, and j as variables to obtain the temporary combined signal sequence plist[j]:

[0051]

[0052] In the above formula, the summation symbol represents the corresponding addition and summation of array elements. Therefore, the length of plist[j] is also L; since there is a pulse overlap phenomenon at this time, plist[j] does not represent the final combined output result, but only serves as an important criterion for pulse optimization and selection.

[0053] Step S14: Take the radar that emits the current signal as the main line, perform pulse optimization and selection to obtain the effective combined sequence alist.

[0054] Further, for the pulse optimization selection described in step S14, the selection scheme as shown in Appendix Figure 2 is adopted, and its algorithm steps are as follows:

[0055] (1) In the initial state, the radar serial number lsa of the transmitted signal is 0;

[0056] (2) Set i as the loop variable, satisfying (for i = 0; i < L; i++).

[0057] (3) When plist[i] = 0 and plist[i + 1]!= 0 simultaneously, the new pulse transmission condition is satisfied. Record the radar serial number k at this time, then lsa = k;

[0058] (4) When the new pulse transmission condition described in (3) is not satisfied, if there exists plist[i]!= 0 and plist[i + 1]!= 0 and plist[i + 1]!= plist[i] and dlist[lsa][t][i + 1] = 0, that is, the combined path sequence value is not zero and changes; and dlist[lsa][t][i + 1] = 0, that is, this change occurs at the trailing edge of the current retained pulse sequence, then retain this pulse, and record the radar serial number k corresponding to this pulse, then lsa = k;

[0059] In step S15, set a reference value maxt with an initial value of 0. Calculate the number of pulses or duty cycle n of the combined path output alist when the current delay of each path is τ[k]. If n > maxt, then maxt = n, and record the delay τ[k] of each path at this time. Based on the above method, find the value of τ[k] when the total number of pulses (duty cycle) in the combined path pulse sequence is the largest. The combined path pulse sequence generated based on this delay value is the optimal combined path output sequence, as shown in Appendix Figure 3 (with the largest duty cycle).

[0060] Further, for the generation of the combined path signal described in step S1, since the operation involves processes and factors such as multi-dimensional array traversal, loop nesting, superposition and selection, and complex structures, the computational amount is relatively large; coupled with limited hardware conditions such as computer memory and the number of CPU cores, there will be a problem that the operation time is too long due to the excessive computational amount, and the performance verification of the alarm device cannot be completed quickly. To solve this problem, multi-threaded operation is proposed. When designing the program, change the core time-consuming operations to multi-threaded parallel operation. Each thread occupies an independent CPU core, and the operations do not interfere with each other. And during the operation process, the operator can still operate the software main interface to perform other tasks. For example, if the computer CPU is configured with 8 cores, then according to the traversal method, the traversal range of the variable t in dlist[k, t, j] within each thread is only 1 / 8 of the reference signal p 0 ; in this way, the overall time consumption will be greatly shortened by 7 / 8.

[0061] Further, the pulse description word in step S2 should include the pulse arrival time, pulse width, pulse repetition interval, pulse amplitude, and carrier frequency of each pulse; combined with the message header and message tail, this pulse description word can be used as a message for real-time calculation by the FPGA; all parameters are encoded in hexadecimal, where the contents of the message header and message tail are fixed, and the remaining data is generated according to the principle that the low data bits come first and the high data bits come later. Based on the above rules, the combined output pulse sequence can be converted into a PDW sequence file, as shown in Attachment Figure 4 , for hardware reading.

Claims

1. A method for combining and sorting pulses of multiple radiation sources, characterized in that, it includes: Step S1: According to the given signal parameters of multiple radiation sources, delay control is performed on each path of signals in turn to change the pulse arrival time to generate a combined signal sequence, seek the optimal output effect, and record the pulse delay data of each path. Specifically, it includes: Construct a multi-source signal sequence array with a dimension of 3, denoted by dlist[k, t, j]. The meanings of each dimension are: k: radar serial number, 0 ≤ k < rnum, where rnum is the number of radars; t: Signal delay amount, with the unit of 1 μs; assume the pulse repetition interval (PRI) of the reference sequence is p 0 , using the periodicity of the pulse signal, the delay range of each of the remaining sequences only needs to generate a delay length of one repetition period relative to the reference signal to include the optimal combining effect, that is, 0 ≤ t < p 0 ; j: discrete time point in the signal sequence, with the unit of 1 μs, 0 ≤ j < L; Step S13: Use k, t, j as variables to perform triple traversal to obtain the temporary combined signal sequence plist[j]: In the above formula, the summation symbol represents the corresponding addition and summation of array elements. The length of plist[j] is L; since there is a pulse overlap phenomenon at this time, plist[j] does not represent the final combined output result, but only serves as an important criterion for pulse optimization and selection; taking the radar that emits the current signal as the main line, perform pulse optimization and selection to obtain the effective combined sequence alist. Specifically: (1) In the initial state, the radar serial number lsa of the emitted signal is 0; (2) Set i as the loop variable, satisfying (for i = 0; i < L; i++); (3) When plist[i] = 0 and plist[i + 1]!= 0, the new pulse emission condition is satisfied. Record the radar serial number k at this time, then lsa = k; (4) When the new pulse emission condition is not satisfied, if there exists plist[i]!= 0 and plist[i + 1]!= 0 and plist[i + 1]!= plist[i], that is, the combined sequence value is not zero and changes; and dlist[lsa][t][i + 1] = 0, that is, this change occurs at the trailing edge of the current reserved pulse sequence, then retain this pulse and record the radar serial number k corresponding to this pulse, then lsa = k; Set a reference value maxt with an initial value of 0; calculate the number of pulses or duty cycle n in the combined output alist when the current delay of each path is τ[k]. If n > maxt, then maxt = n, and record the current delay of each path τ[k]; Step S2: Sort according to the pulse delay data of each path corresponding to the optimal output effect to generate a high-density pulse description word sequence.

2. The method for combining and sorting pulses of multiple radiation sources according to claim 1, characterized in that, the signal parameters described in Step S1 include the pulse width, pulse repetition interval, pulse amplitude, and carrier frequency of each radiation source signal, and the above parameter values of each path of signals are constant during the sorting process.

3. The method for combining and sorting pulses of multiple radiation sources according to claim 1, characterized in that, the following content is also included in Step S1: First, according to the multiple signals provided by the scenario, arbitrarily select one path as the reference sequence, and this sequence will not be subjected to delay processing; then select the signal sequence with the largest PRI from the multiple signals, and let its PRI be p m , starting from the 0 moment, intercept n m pulse repetition periods, then the sequence length L can be expressed as: L = p m *n m The lengths of the remaining sequences are all L, and the number of pulses n contained in the signal sequence with the serial number k k is as follows: n k = INT(L / p k ) where p k represents the PRI value of the signal sequence numbered k, and satisfies p k ≤ p m , and INT represents the integer operation.

4. The method for combining and sorting pulses of multiple radiation sources according to claim 1, characterized in that, The generation of the combined signal sequence described in step S1 can adopt multi-threaded operations: when designing the program, change the core time-consuming operations into multi-threaded parallel operations. Each thread occupies an independent CPU core, and the operations do not interfere with each other. During the operation process, the operator can still operate the main software interface to perform other tasks.

5. The multi-radiation source combined pulse sorting method according to claim 1, characterized in that the pulse descriptor described in step S2 includes the pulse arrival time, pulse width, pulse repetition interval, pulse amplitude, and carrier frequency of each pulse; combined with the message header and message tail, this pulse descriptor can be used as a message for real-time calculation by the FPGA; all parameters are encoded in hexadecimal. Among them, the contents of the message header and message tail are fixed, and the rest of the data are generated according to the principle of low data bits first and high data bits later. The combined output pulse sequence can be converted into a PDW sequence file for hardware reading.

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