A method and system for sorting and measuring parameters of multi-source pulse signals in digital radar

Abstract

This application discloses a digital radar multi-source pulse signal sorting and parameter measurement method and system. The method includes: traversing all sampling points, re-acquiring and recording the rising and falling edges according to the amplitude determination threshold; taking the recorded rising edge as TOA and performing signal sorting on the TOA signal, wherein PRIM is acquired and sequence retrieval is performed to extract the retrieved target pulse train; traversing the target pulse train to calculate and record the first pulse width, and after traversal, acquiring the measurement parameters of the pulse signal; traversing the target pulse train again to calculate the second pulse width, and extracting pulses whose second pulse width differs from the corresponding first pulse width by less than a certain value, and acquiring the carrier frequency and bandwidth based on all extracted pulses as frequency domain parameters; taking the remaining pulse train after extracting the target pulse train as a new signal input, repeating the above steps, and exiting the loop when the loop exit condition is met.

Description

Technical Field

[0001] This application relates to the field of radar signal processing technology, and more specifically, to a method and system for sorting and measuring parameters of multi-source pulse signals in digital radar. Background Technology

[0002] In radar development, to save costs, software simulation of radar characteristics is often used for research. With the improvement of computing power, digital radar simulation has gradually become a mainstream radar research method. In complex electronic warfare environments, passive radars typically receive dense, overlapping pulse trains emitted by multiple radars. Existing technologies generally use envelope detectors and threshold detection methods to measure time-of-arrival parameters such as pulse width, and multiple correlators to measure carrier frequency and bandwidth frequency-domain parameters. However, for parameter measurement in digital radar simulation, most current methods only process single radar signals. For multi-source radar pulse signals, due to differences in parameters, pulses will overlap, especially significantly affecting the pulse width, bandwidth, and carrier frequency. If only a single signal is measured, there is a high probability that the measured time and frequency domain parameters will be inaccurate, thus affecting subsequent processing. Summary of the Invention

[0003] This application provides a digital radar multi-source pulse signal sorting and parameter measurement method and system, which solves the problem in the prior art that the time and frequency domain parameters cannot be accurately measured when processing multi-source radar signals.

[0004] The specific technical solution is as follows:

[0005] In a first aspect, embodiments of this application provide a method for sorting and measuring parameters of multi-source pulse signals using digital radar, including:

[0006] S1. Set the amplitude determination threshold, and set the flag of all rising edges in the digital radar multi-source pulse signal to 1. Traverse all sampling points of the pulse signal, reacquire and record the rising and falling edges according to the amplitude determination threshold, and set the flag of the rising edge to 0 and the flag of the falling edge to 1.

[0007] S2. The recorded rising edge is taken as the pulse arrival time TOA. The TOA signal is sorted based on the modified PRI transform algorithm. The maximum value in the PRI transform spectrum is obtained. If it exceeds the judgment threshold, the maximum value is defined as PRIM. Sequence retrieval is performed based on PRIM, and the retrieved target pulse string is extracted.

[0008] S3. Traverse all signals of the target pulse train, reacquire and record the rising and falling edges according to the amplitude determination threshold, calculate and record the first pulse width, and after traversing all signals, obtain the mode of all first pulse widths and use the mode as the measurement parameter of the pulse signal. ;

[0009] S4. Repeat step S3 to iterate through all signals in the target pulse train again, calculate the second pulse width, and extract the pulses whose width differs from the corresponding first pulse width by less than 1 / 3. The pulse is used to obtain the carrier frequency and bandwidth based on all the captured pulses using the digital instantaneous frequency measurement method, which are used as the frequency domain parameters of the pulse signal.

[0010] S5. Take the remaining pulse train after extracting the target pulse train from the pulse signal as a new signal input, and repeat steps S1–S4. If the number of extracted TOA is less than the preset threshold, or there is no valid PRI, or no valid measurement parameter is extracted, then exit the loop.

[0011] In some embodiments of this application, the step of reacquiring and recording the rising edge and falling edge according to the amplitude determination threshold specifically includes: if the amplitude of the sampling point is greater than the amplitude determination threshold and the flag is 1, then the subscript of the sampling point is recorded as a rising edge; if the amplitudes of two consecutive sampling points are less than the amplitude determination threshold, then the subscript of the current sampling point is recorded as a falling edge.

[0012] In some embodiments of this application, the modified PRI transformation algorithm includes:

[0013] The estimated IPR range is divided into several PRI transform boxes; the PRI transform spectrum is calculated for all PRI transform boxes within the jitter range of the transform boxes. and autocorrelation coefficient The calculation formula is as follows:

[0014] ;

[0015] ;

[0016] in, Indicates the first TOA of one pulse; Indicates the first TOA of one pulse; Indicates the length of the pulse sequence; Indicates the first The pulse and the first The time interval between pulses ; For the impact signal function; It is an exponential function; The imaginary unit;

[0017] The judgment threshold value is calculated using the following formula:

[0018] ;

[0019] ;

[0020] ;

[0021] ;

[0022] ;

[0023] in, Indicates the first The length of each PRI converter box; Indicates the amount of jitter; Indicates the first The time interval between each PRI converter box; Indicates the first PRI transform spectrum of a PRI transform box The absolute value; Indicates the observation time; , , All parameters are adjustable. , , ; Indicates the first The autocorrelation coefficients of each PRI transform box; Indicates pulse current density; Indicates the first The judgment threshold value of each PRI converter box;

[0024] Based on the judgment threshold and the PRI transform spectrum, determine whether the pulse follows the PRI corresponding to the PRI transform box. Then it is determined that the group of pulses follows the first... The PRI corresponding to the PRI transformation box must be specified; otherwise, it is determined that the PRI is not followed.

[0025] In some embodiments of this application, the modified PRI transform algorithm employs overlapping PRI transform bins and a variable time starting point. Specifically, determining whether to update the time starting point by calculating the initial phase value includes:

[0026] The initial phase value was calculated. The calculation formula is as follows:

[0027] ;

[0028] in, Indicates the first TOA of one pulse, Indicates the current starting point of time. This indicates the size of the PRI corresponding to each point in the PRI transformation box;

[0029] Initial phase value The decomposition is performed, and the specific decomposition formula is as follows:

[0030] ;

[0031] like and ,or and Then update the starting time, let Otherwise, the starting time will not be updated; among them, Indicates the first TOA of one pulse, It is a constant.

[0032] In some embodiments of this application, the range of the variable box jitter is: ,in, This indicates the amount of jitter.

[0033] In some embodiments of this application, the step of performing sequence retrieval based on the PRIM and extracting the retrieved pulse train specifically includes:

[0034] The PRI jitter range is calculated based on PRIM, using the following formula:

[0035] ;

[0036] ;

[0037] in, Indicates the amount of jitter; This indicates the maximum value of PRI. This indicates the minimum PRI value, i.e., the PRI jitter range. ;

[0038] Iterate through all TOA signals of the pulse signal, starting from the beginning of the TOA sequence, and perform subtraction on adjacent terms in turn. If the difference is within the PRI jitter range, extract the current two TOA times. After the iteration is complete, record all extracted TOA times.

[0039] The pulse signal is indexed based on the recorded TOA time, and the corresponding target pulse train is extracted.

[0040] In some embodiments of this application, obtaining the carrier frequency and bandwidth using digital instantaneous frequency measurement based on all captured pulses specifically includes:

[0041] Calculate the corresponding corrected signal frequency for each of the captured pulses using the following formula:

[0042] ;

[0043] ;

[0044] in, For the first The signal expression of each captured pulse; It is an exponential function; The signal frequency; For signal phase;

[0045] set up ,in, If it is the imaginary unit, then ;

[0046] Pick ,in, If the sampling rate is , then ;

[0047] because ,and Therefore, the signal frequency is corrected. for:

[0048] ;

[0049] The instantaneous frequency sequence is obtained based on all the calculated corrected signal frequencies;

[0050] The carrier frequency is obtained based on the instantaneous frequency sequence, and the frequency distribution is obtained by performing spectral analysis on the instantaneous frequency sequence. The broadband is then obtained based on the frequency distribution.

[0051] In some embodiments of this application, obtaining the carrier frequency based on the instantaneous frequency sequence specifically includes: averaging the instantaneous frequency sequence to obtain the carrier frequency; or,

[0052] The step of obtaining the carrier frequency based on the instantaneous frequency sequence specifically includes: using a spectrum analysis method to determine the frequency points of energy concentration, and using the frequency points of energy concentration as the carrier frequency.

[0053] In some embodiments of this application, the step of performing spectral analysis on the instantaneous frequency sequence to obtain the frequency distribution specifically includes: using a Fast Fourier Transform (FFT) to convert the instantaneous frequency sequence in the time domain to the frequency domain to obtain the frequency distribution.

[0054] Secondly, embodiments of this application provide a digital radar multi-source pulse signal sorting and parameter measurement system, including:

[0055] The rising and falling edge acquisition module is used to set the amplitude determination threshold, set the flag of all rising edges in the digital radar multi-source pulse signal to 1, traverse all sampling points of the pulse signal, reacquire and record the rising and falling edges according to the amplitude determination threshold, and set the flag of the rising edge to 0 and the flag of the falling edge to 1.

[0056] The signal sorting module is used to take the recorded rising edge as the pulse arrival time TOA, and to sort the TOA signal based on the modified PRI transform algorithm. Specifically, the maximum value in the PRI transform spectrum is obtained. If it exceeds the judgment threshold, the maximum value is defined as PRIM. Sequence retrieval is performed based on PRIM, and the retrieved target pulse train is extracted.

[0057] The measurement parameter acquisition module is used to traverse all signals of the target pulse train, reacquire and record the rising and falling edges according to the amplitude determination threshold, calculate and record the first pulse width, and after traversal, obtain the mode of all the first pulse widths and use the mode as the measurement parameter of the pulse signal. ;

[0058] The frequency domain parameter acquisition module is used to re-traverse all signals of the target pulse train, re-acquire and record the rising and falling edges according to the amplitude determination threshold, calculate the second pulse width, and truncate the second pulse width to a value less than the difference between the second pulse width and its corresponding first pulse width. The pulse is used to obtain the carrier frequency and bandwidth based on all the captured pulses using the digital instantaneous frequency measurement method, which are used as the frequency domain parameters of the pulse signal.

[0059] The loop creation and exit module is used to input the remaining pulse train after extracting the target pulse train of the pulse signal as a new signal into the rising and falling edge acquisition module, repeating the signal sorting and frequency domain parameter acquisition steps. At the same time, if the number of extracted TOA is less than a preset threshold, or there is no valid PRI, or no valid measurement parameter is extracted, the loop exits.

[0060] The beneficial effects of the embodiments of this application are as follows:

[0061] This digital radar multi-source pulse signal sorting and parameter measurement method can be applied to digital passive radar signals in complex multi-source environments. It solves the problem that existing technologies cannot accurately measure time and frequency domain parameters when processing multi-source radar signals. While possessing a certain degree of stability, it reduces the degree of human intervention in the signal processing of existing classical algorithms, enabling the system to automatically extract signals and calculate parameters. Moreover, the extracted signals and parameters can be used as subsequent processing conditions for digital radar signals, possessing a certain degree of realism. Attached Figure Description

[0062] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0063] Figure 1 A flowchart illustrating a digital radar multi-source pulse signal sorting and parameter measurement method provided in an embodiment of this application;

[0064] Figure 2 This is a block diagram of a digital radar multi-source pulse signal sorting and parameter measurement system provided in an embodiment of this application. Detailed Implementation

[0065] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. 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.

[0066] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The terms "comprising" and "having," and any variations thereof, in the embodiments and drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0067] This application discloses a method for sorting and measuring parameters of multi-source pulse signals using digital radar. These methods are described in detail below.

[0068] The digital radar multi-source pulse signal sorting and parameter measurement method includes the following steps:

[0069] S1. Set the amplitude judgment threshold and set the flag of all rising edges in the digital radar multi-source pulse signal to 1. Traverse all sampling points of the pulse signal, reacquire and record the rising and falling edges according to the amplitude judgment threshold, and set the flag of the rising edge to 0 and the flag of the falling edge to 1.

[0070] Here, pulse signal is short for digital radar multi-source pulse signal. Rising edge refers to the instant the signal changes from low to high level; falling edge refers to the instant the signal changes from high to low level. Amplitude threshold refers to the threshold used to determine whether the signal amplitude reaches a specific standard.

[0071] In some embodiments, when traversing all sampling points of the pulse signal, if the amplitude of a sampling point is greater than the amplitude determination threshold and the flag is 1, then the footer of that sampling point is recorded as a rising edge; if the amplitudes of two consecutive sampling points are less than the amplitude determination threshold, then the footer of the current sampling point (referring to the sampling point after two consecutive sampling points) is recorded as a falling edge. This process is repeated until all sampling points have been traversed. In a specific implementation, the noise level of 3dB can be set as the amplitude determination threshold.

[0072] S2. The recorded rising edge is taken as the pulse arrival time TOA. The TOA signal is sorted based on the modified PRI transform algorithm. The maximum value in the PRI transform spectrum is obtained. If it exceeds the judgment threshold, the maximum value is defined as PRIM. Sequence retrieval is performed based on PRIM, and the retrieved target pulse train is extracted.

[0073] The Time of Arrival (TOA) refers to the point in time when the pulse signal arrives at the receiver. The Pulse Repetition Interval (PRI) is the time interval between two consecutive pulses, which is an important characteristic parameter of radar signals, and different radars typically have different PRI values.

[0074] In some embodiments, the modified PRI transformation algorithm includes:

[0075] The estimated IPR range is divided into several PRI transform boxes; the PRI transform spectrum is calculated for all PRI transform boxes within the jitter range of the transform boxes. and autocorrelation coefficient The calculation formula is as follows:

[0076] ;

[0077] ;

[0078] in, Indicates the first TOA of one pulse; Indicates the first TOA of one pulse; Indicates the length of the pulse sequence; Indicates the first The pulse and the first The time interval between pulses ; For the impact signal function; It is an exponential function; It is the imaginary unit.

[0079] In the embodiments of this application, the modified PRI transform algorithm uses overlapping PRI transform boxes and a variable time start point to adapt to frequency repetition jitter.

[0080] Furthermore, the decision to update the time starting point is made by calculating the initial phase value, specifically including:

[0081] The initial phase value was calculated. The calculation formula is as follows:

[0082] ;

[0083] in, Indicates the first TOA of one pulse, Indicates the current starting point of time. This indicates the size of the PRI corresponding to each point in the PRI transformation box;

[0084] Initial phase value The decomposition is performed, and the specific decomposition formula is as follows:

[0085] ;

[0086] like and ,or and Then update the starting time, let Otherwise, the starting time will not be updated; among them, Indicates the first TOA of one pulse; It is a constant, usually taking the value 0.01.

[0087] Furthermore, the variation box jitter range in this embodiment is based on the jitter amount. Calculated, specifically ,in, Indicates the amount of jitter. Indicates the first The pulse and the first The time interval between pulses.

[0088] The PRI transform spectrum and autocorrelation coefficient of each PRI transform box are calculated. Then, the judgment threshold is calculated using the following formula:

[0089] ;

[0090] ;

[0091] ;

[0092] ;

[0093] ;

[0094] in, Indicates the first The length of each PRI converter box; Indicates the amount of jitter; Indicates the first The time interval between each PRI converter box; Indicates the first PRI transform spectrum of a PRI transform box The absolute value; Indicates the observation time; , , All parameters are adjustable. , , ; Indicates the first The autocorrelation coefficients of each PRI transform box; Indicates pulse current density; Indicates the first The judgment threshold value of each PRI converter box.

[0095] Based on the threshold value and the PRI transform spectrum, determine whether the pulse follows the PRI corresponding to the PRI transform box. For details, for the... PRI transform spectrum corresponding to each PRI transform box ,like Then it is determined that the group of pulses follows the first... The PRI corresponding to each PRI transformation box indicates that the pulse group has a pulse repetition pattern that matches the characteristics represented by the PRI transformation box; otherwise, it is determined that it does not follow the pattern.

[0096] This application uses a PRI converter to sort pulses according to their corresponding PRI signals, which can effectively separate signals from different radars in a complex pulse signal environment, providing a foundation for subsequent signal processing and analysis.

[0097] In other embodiments, sequence retrieval is performed based on PRIM, and the retrieved pulse trains are extracted, specifically including:

[0098] The PRI jitter range is calculated based on PRIM, and all PRI values ​​within this range are considered to meet the condition to address the jitter issue in the repetition frequency of the actual acquired signal. The detailed formulas for calculating the maximum and minimum PRI values ​​are as follows:

[0099] ;

[0100] ;

[0101] in, Indicates the amount of jitter; This indicates the maximum value of PRI. This indicates the minimum PRI value, i.e., the PRI jitter range. ;

[0102] Iterate through all TOA signals of the pulse signal, starting from the beginning of the TOA sequence, and subtract adjacent terms in turn. If the difference is within the PRI jitter range, extract the current two TOA times. After the iteration is complete, record all extracted TOA times.

[0103] The pulse signal is indexed based on the recorded TOA time, and the corresponding target pulse train is extracted.

[0104] S3. Traverse all signals in the target pulse train, reacquire and record the rising and falling edges according to the amplitude threshold, calculate and record the first pulse width, and after traversing all signals, obtain the mode of all first pulse widths and use the mode as the measurement parameter of the pulse signal. .

[0105] Specifically, similar to step S1, the rising and falling edges of the retrieved target pulse train are captured again. Each time a falling edge is captured, the corresponding time of the falling edge is subtracted from the time of the previously acquired rising edge to calculate and record the first pulse width. After traversing all signals, the mode of all calculated first pulse widths is taken as the measurement parameter of the pulse signal. .

[0106] S4. Repeat step S3 to iterate through all signals in the target pulse train, calculate the second pulse width, and extract the pulses whose widths differ from their corresponding first pulse widths by less than 1 / 3. The carrier frequency and bandwidth are obtained using digital instantaneous frequency measurement based on all the captured pulses, and are used as frequency domain parameters of the pulse signal.

[0107] This application is based on the measurement parameters obtained in step S3. The pulse signals are initially screened to address the issue of multi-pulse aliasing in the acquired signals.

[0108] In some embodiments, the carrier frequency and bandwidth are obtained using Digital Instantaneous Frequency Measurement (DIFM) based on all captured pulses, specifically including:

[0109] Calculate the corresponding corrected signal frequency for each of the captured pulses using the following formula:

[0110] ;

[0111] ;

[0112] in, For the first The signal expression of each captured pulse; It is an exponential function; The signal frequency; For signal phase;

[0113] set up ,in, If it is the imaginary unit, then ,have to ;

[0114] Pick ,in, If the sampling rate is , then ;

[0115] because ,and Therefore, the signal frequency is corrected. for:

[0116] ;

[0117] The instantaneous frequency sequence is obtained based on all the calculated corrected signal frequencies;

[0118] The carrier frequency is obtained from the instantaneous frequency sequence, and the frequency distribution is obtained by performing spectral analysis on the instantaneous frequency sequence. The broadband is then obtained from the frequency distribution.

[0119] In practical implementation, the carrier frequency can be obtained by averaging the instantaneous frequency sequence; alternatively, spectral analysis can be used to determine the frequency points where energy is concentrated, and these frequency points can be used as the carrier frequency. Alternatively, the Fast Fourier Transform (FFT) can be used to transform the instantaneous frequency sequence in the time domain to the frequency domain to obtain the frequency distribution.

[0120] S5. Use the remaining pulse train after extracting the target pulse train as the new signal input, and repeat steps S1–S4. If the number of extracted TOA is less than the preset threshold, or there is no valid PRI, or no valid measurement parameter is extracted, then exit the loop.

[0121] The above describes the steps of the digital radar multi-source pulse signal sorting and parameter measurement method provided in this embodiment. The following section will combine... Figure 1 The overall process of a specific embodiment of a digital radar multi-source pulse signal sorting and parameter measurement method is described in detail.

[0122] Step S110: Acquire signal.

[0123] This involves acquiring digital radar multi-source pulse signals that require signal sorting and parameter measurement.

[0124] Step S120: Detection of top and bottom edges and TOA.

[0125] Set the noise level to 3dB as the amplitude threshold, and set the rising edge flag of all acquired digital radar multi-source pulse signals to 1. Then, iterate through all sampling points in the pulse signal. If the amplitude of a sampling point is greater than the set amplitude threshold and the flag is 1, record the current point as a rising edge and set the rising edge flag to 0. Simultaneously, if the amplitudes of two consecutive sampling points are less than the set amplitude threshold, record the current point as a falling edge and set the falling edge flag to 1. Repeat this process until all sampling points have been traversed, thus acquiring all rising and falling edges in the pulse signal. Finally, use all recorded rising edges as the TOA (Time of Arrival).

[0126] Step S130: Determine if the number of TOA is less than 3.

[0127] Set the preset threshold to 3. Determine whether the number of TOA obtained in step S120 is less than 3. If it is less, end the process; if it is not less, proceed from step S130 to step S140.

[0128] Step S140: Signal sorting.

[0129] The TOA signal is sorted based on the modified PRI transform algorithm.

[0130] Step S150: No valid PRI.

[0131] In step S140, the signal is sorted to determine whether there is a pulse that follows the PRI corresponding to the PRI converter box. If there is no pulse, i.e. there is no valid PRI, the process ends; if there is a pulse, i.e. there is a valid PRI, the process proceeds from step S150 to step S160.

[0132] Step S160: Sequence retrieval.

[0133] Take the maximum value in the PRI transform spectrum obtained in step S140 above. If this value exceeds the judgment threshold calculated in the modified PRI transform algorithm, record the PRI size as PRIM. Perform sequence retrieval based on PRIM and extract the retrieved target pulse train.

[0134] Step S170: Pulse width measurement.

[0135] After step S160, all signals in the target pulse train are traversed. The rising and falling edges are reacquired and recorded according to the amplitude determination threshold. The first pulse width is calculated and recorded. After traversal, the mode of all first pulse widths is obtained, and the mode is used as the measurement parameter of the pulse signal. Then, iterate through all signals in the target pulse train again, reacquire and record the rising and falling edges based on the amplitude threshold, calculate the second pulse width, and truncate the second pulse width to the point where the difference between the second pulse width and its corresponding first pulse width is less than 1 / 3. The pulse.

[0136] Step S180: No effective pulse width.

[0137] In step S170, it is determined whether there are valid measurement parameters that can be extracted. If there is no effective pulse width, proceed from step S180 to step S190; if an effective pulse width is extracted, return from step S180 to step S120, use the extracted remaining pulse train as the new input signal, and repeat the above steps to perform the next round of signal sorting and parameter measurement.

[0138] Step S190: Carrier frequency and bandwidth acquisition.

[0139] Based on all the pulses captured in step S170, the carrier frequency and bandwidth are obtained using the digital instantaneous frequency measurement method, which are then used as the frequency domain parameters of the pulse signal, and the process ends.

[0140] Corresponding to the above method embodiments, this application also provides a digital radar multi-source pulse signal sorting and parameter measurement system for executing the steps of the digital radar multi-source pulse signal sorting and parameter measurement method in the above embodiments. For example... Figure 2As shown, the digital radar multi-source pulse signal sorting and parameter measurement system 200 includes: a rising and falling edge acquisition module 210, a signal sorting module 220, a measurement parameter acquisition module 230, a frequency domain parameter acquisition module 240, and a loop creation and exit module 250.

[0141] Specifically, the rising and falling edge acquisition module 210 is used to set the amplitude determination threshold, and set the flag of all rising edges in the digital radar multi-source pulse signal to 1. It traverses all sampling points of the pulse signal, reacquires and records the rising and falling edges according to the amplitude determination threshold, and sets the flag of the rising edge to 0 and the flag of the falling edge to 1.

[0142] The signal sorting module 220 is used to take the recorded rising edge as the pulse arrival time TOA, and to sort the TOA signal based on the modified PRI transform algorithm. Specifically, the maximum value in the PRI transform spectrum is obtained. If it exceeds the judgment threshold, the maximum value is defined as PRIM. Sequence retrieval is performed based on PRIM, and the retrieved target pulse train is extracted.

[0143] The measurement parameter acquisition module 230 is used to traverse all signals of the target pulse train, reacquire and record the rising and falling edges according to the amplitude determination threshold, calculate and record the first pulse width, and after traversal, obtain the mode of all first pulse widths and use the mode as the measurement parameter of the pulse signal. .

[0144] The frequency domain parameter acquisition module 240 is used to re-traverse all signals of the target pulse train, re-acquire and record the rising and falling edges according to the amplitude determination threshold, calculate the second pulse width, and truncate the second pulse width to the first pulse width whose difference is less than 1 / 3. The carrier frequency and bandwidth are obtained using digital instantaneous frequency measurement based on all the captured pulses, and are used as frequency domain parameters of the pulse signal.

[0145] The loop creation and exit module 250 is used to take the remaining pulse train after the target pulse train is extracted from the pulse signal as the new signal input rising and falling edge acquisition module, repeat the signal sorting and frequency domain parameter acquisition steps, and exit the loop if the number of extracted TOA is less than the preset threshold, or there is no valid PRI, or no valid measurement parameter is extracted.

[0146] In summary, this application discloses a method and system for sorting and measuring parameters of multi-source pulse signals in digital radar. It can be applied to digital passive radar signals in complex multi-source environments, solving the problem that existing technologies cannot accurately measure time and frequency domain parameters when processing multi-source radar signals. While possessing a certain degree of stability, it reduces the degree of human intervention in the signal processing of existing classical algorithms, enabling the system to automatically extract signals and calculate parameters. Moreover, the extracted signals and parameters can be used as subsequent processing conditions for digital radar signals, possessing a certain degree of realism.

[0147] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0148] Those skilled in the art will understand that the modules in the apparatus of the embodiments can be distributed in the apparatus of the embodiments as described in the embodiments, or they can be located in one or more devices different from this embodiment with corresponding changes. The modules of the above embodiments can be combined into one module, or they can be further divided into multiple sub-modules.

[0149] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for sorting and measuring parameters of multi-source pulse signals in digital radar, characterized in that, include: S1. Set the amplitude determination threshold, and set the flag of all rising edges in the digital radar multi-source pulse signal to 1. Traverse all sampling points of the pulse signal, reacquire and record the rising and falling edges according to the amplitude determination threshold, and set the flag of the rising edge to 0 and the flag of the falling edge to 1. S2. The recorded rising edge is taken as the pulse arrival time TOA. The TOA signal is sorted based on the modified PRI transform algorithm. The maximum value in the PRI transform spectrum is obtained. If it exceeds the judgment threshold, the maximum value is defined as PRIM. Sequence retrieval is performed based on PRIM, and the retrieved target pulse string is extracted. S3. Traverse all signals of the target pulse train, reacquire and record the rising and falling edges according to the amplitude determination threshold, calculate and record the first pulse width, and after traversing all signals, obtain the mode of all first pulse widths and use the mode as the measurement parameter of the pulse signal. ; S4. Repeat step S3 to iterate through all signals in the target pulse train again, calculate the second pulse width, and extract the pulses whose width differs from the corresponding first pulse width by less than 1 / 3. The pulse is used to obtain the carrier frequency and bandwidth based on all the captured pulses using the digital instantaneous frequency measurement method, which are used as the frequency domain parameters of the pulse signal. S5. Take the remaining pulse train after extracting the target pulse train from the pulse signal as a new signal input, and repeat steps S1–S4. If the number of extracted TOA is less than the preset threshold, or there is no valid PRI, or no valid measurement parameter is extracted, then exit the loop.

2. The digital radar multi-source pulse signal sorting and parameter measurement method according to claim 1, characterized in that, The step of re-acquiring and recording the rising and falling edges based on the amplitude determination threshold specifically includes: if the amplitude of a sampling point is greater than the amplitude determination threshold and the flag is 1, then the subscript of the sampling point is recorded as a rising edge; if the amplitudes of two consecutive sampling points are less than the amplitude determination threshold, then the subscript of the current sampling point is recorded as a falling edge.

3. The digital radar multi-source pulse signal sorting and parameter measurement method according to claim 1, characterized in that, The modified PRI transformation algorithm includes: The estimated IPR range is divided into several PRI transform boxes; the PRI transform spectrum is calculated for all PRI transform boxes within the jitter range of the transform boxes. and autocorrelation coefficient The calculation formula is as follows: ； ； in, Indicates the first TOA of one pulse; Indicates the first TOA of one pulse; Indicates the length of the pulse sequence; Indicates the first The pulse and the first The time interval between pulses ; For the impact signal function; It is an exponential function; The imaginary unit; The judgment threshold value is calculated using the following formula: ； ； ； ； ； in, Indicates the first The length of each PRI converter box; Indicates the amount of jitter; Indicates the first The time interval between each PRI converter box; Indicates the first PRI transform spectrum of a PRI transform box The absolute value; Indicates the observation time; , , All parameters are adjustable. , , ; Indicates the first The autocorrelation coefficients of each PRI transform box; Indicates pulse current density; Indicates the first The judgment threshold value of each PRI converter box; Based on the judgment threshold and the PRI transform spectrum, determine whether the pulse follows the PRI corresponding to the PRI transform box. Then the pulse is determined to follow the first... The PRI corresponding to the PRI transformation box must be specified; otherwise, it is determined that the PRI is not followed.

4. The digital radar multi-source pulse signal sorting and parameter measurement method according to claim 3, characterized in that, The modified PRI transform algorithm employs overlapping PRI transform bins and a variable time starting point. Specifically, it determines whether to update the time starting point by calculating the initial phase value, including: The initial phase value was calculated. The calculation formula is as follows: ； in, Indicates the first TOA of one pulse, Indicates the current starting point of time. This indicates the size of the PRI corresponding to each point in the PRI transformation box; Initial phase value The decomposition is performed, and the specific decomposition formula is as follows: ； like and ,or and Then update the starting time, let Otherwise, the starting time will not be updated; among them, Indicates the first TOA of one pulse, It is a constant.

5. The digital radar multi-source pulse signal sorting and parameter measurement method according to claim 3, characterized in that, The vibration range of the variable box is: ,in, This indicates the amount of jitter.

6. The digital radar multi-source pulse signal sorting and parameter measurement method according to claim 1, characterized in that, The step of performing sequence retrieval based on the PRIM and extracting the retrieved pulse train specifically includes: The PRI jitter range is calculated based on PRIM, using the following formula: ； ； in, Indicates the amount of jitter; This indicates the maximum value of PRI. This indicates the minimum PRI value, i.e., the PRI jitter range. ; Iterate through all TOA signals of the pulse signal, starting from the beginning of the TOA sequence, and perform subtraction on adjacent terms in turn. If the difference is within the PRI jitter range, extract the current two TOA times. After the iteration is complete, record all extracted TOA times. The pulse signal is indexed based on the recorded TOA time, and the corresponding target pulse train is extracted.

7. The digital radar multi-source pulse signal sorting and parameter measurement method according to claim 1, characterized in that, The process of obtaining the carrier frequency and bandwidth using digital instantaneous frequency measurement based on all captured pulses specifically includes: Calculate the corresponding corrected signal frequency for each of the captured pulses using the following formula: ； ； in, For the first The signal expression of each captured pulse; It is an exponential function; The signal frequency; For signal phase; set up ,in, If it is the imaginary unit, then ; Pick ,in, If the sampling rate is , then ; because ,and Therefore, the signal frequency is corrected. for: ； The instantaneous frequency sequence is obtained based on all the calculated corrected signal frequencies; The carrier frequency is obtained based on the instantaneous frequency sequence, and the frequency distribution is obtained by performing spectral analysis on the instantaneous frequency sequence. The broadband is then obtained based on the frequency distribution.

8. The digital radar multi-source pulse signal sorting and parameter measurement method according to claim 7, characterized in that, Obtaining the carrier frequency based on the instantaneous frequency sequence specifically includes: averaging the instantaneous frequency sequence to obtain the carrier frequency; or... The step of obtaining the carrier frequency based on the instantaneous frequency sequence specifically includes: using a spectrum analysis method to determine the frequency points of energy concentration, and using the frequency points of energy concentration as the carrier frequency.

9. The digital radar multi-source pulse signal sorting and parameter measurement method according to claim 7, characterized in that, The step of performing spectral analysis on the instantaneous frequency sequence to obtain the frequency distribution specifically includes: using Fast Fourier Transform (FFT) to transform the instantaneous frequency sequence in the time domain to the frequency domain to obtain the frequency distribution.

10. A digital radar multi-source pulse signal sorting and parameter measurement system, characterized in that, include: The rising and falling edge acquisition module is used to set the amplitude determination threshold, set the flag of all rising edges in the digital radar multi-source pulse signal to 1, traverse all sampling points of the pulse signal, reacquire and record the rising and falling edges according to the amplitude determination threshold, and set the flag of the rising edge to 0 and the flag of the falling edge to 1. The signal sorting module is used to take the recorded rising edge as the pulse arrival time TOA, and to sort the TOA signal based on the modified PRI transform algorithm. Specifically, the maximum value in the PRI transform spectrum is obtained. If it exceeds the judgment threshold, the maximum value is defined as PRIM. Sequence retrieval is performed based on PRIM, and the retrieved target pulse train is extracted. The measurement parameter acquisition module is used to traverse all signals of the target pulse train, reacquire and record the rising and falling edges according to the amplitude determination threshold, calculate and record the first pulse width, and after traversal, obtain the mode of all the first pulse widths and use the mode as the measurement parameter of the pulse signal. ; The frequency domain parameter acquisition module is used to re-traverse all signals of the target pulse train, re-acquire and record the rising and falling edges according to the amplitude determination threshold, calculate the second pulse width, and truncate the second pulse width to a value less than the difference between the second pulse width and its corresponding first pulse width. The pulse is used to obtain the carrier frequency and bandwidth based on all the captured pulses using the digital instantaneous frequency measurement method, which are used as the frequency domain parameters of the pulse signal. The loop creation and exit module is used to input the remaining pulse train after extracting the target pulse train of the pulse signal as a new signal into the rising and falling edge acquisition module, repeating the signal sorting and frequency domain parameter acquisition steps. At the same time, if the number of extracted TOA is less than a preset threshold, or there is no valid PRI, or no valid measurement parameter is extracted, the loop exits.

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