An asynchronous network station sorting method based on frequency hopping signal arrival time

Abstract

This invention provides an asynchronous network station sorting method based on the arrival time of frequency hopping signals, comprising the following steps: buffering the classified set of frequency hopping descriptors with the same hopping rate; precisely estimating the frequency hopping period; obtaining the starting point of the frequency hopping sequence after analysis; initially obtaining a set of network station frequency hopping signals that meet the conditions; correcting the network station frequency set; and outputting the network station results. This method can utilize the characteristics of the arrival time of frequency hopping signals for sorting. The "initial acquisition of the network station frequency hopping signal set" performs coarse classification of the network stations, and the "correction of the network station frequency set" further refines the network station frequency set, improving the sorting accuracy. Since the arrival time of the frequency hopping signal is one of the most fundamental parameters of the frequency hopping signal, this method has strong stability and is applicable to different frequency hopping signals. The arrival time of the frequency hopping signal is acquired in real time, giving this method excellent real-time performance. This method only requires estimation of the frequency hopping period and the starting point of the hopping sequence, resulting in relatively low computational complexity.

Description

Technical Field

[0001] This invention relates to the field of communication technology, specifically to an asynchronous network station sorting method based on the arrival time of frequency hopping signals. Background Technology

[0002] As a key technology in frequency-hopping communication, station sorting technology has developed rapidly. Due to the highly complex nature of actual combat environments, multiple frequency-hopping station signals sometimes exist simultaneously, with arrival times close together and potentially overlapping operating frequency ranges. This significantly increases the difficulty of station sorting. The main challenge with asynchronous stations is separating the target station from the complex multi-station signals. Only after separating the target station can reconnaissance and jamming of a specific target station be carried out based on the frequency-hopping pattern.

[0003] The main methods for network station sorting include blind source separation and frequency hopping descriptor extraction clustering.

[0004] The advantage of blind source separation is that it only utilizes multiple intercepted frequency-hopping stations for blind selection, without needing to extract the characteristics of the frequency-hopping signal in advance. The disadvantages are that it has incompleteness issues; it is not effective for separating blind source signals from four or more stations, and it fails for some nonlinearly mixed observation signals.

[0005] The advantage of frequency-hopping descriptor extraction and clustering methods is that they can achieve sorting of synchronous and asynchronous multi-network stations. Periodic clustering is used to sort different network configurations; DOA (Difference of Arrival) and power parameters are used to sort synchronous stations; and hop time and power parameters are used to sort asynchronous stations. The disadvantage is that it depends on the accurate extraction of the frequency-hopping descriptor; the more accurate the frequency-hopping descriptor, the more accurate the station sorting results. Summary of the Invention

[0006] The purpose of this invention is to solve the problem of accurately sorting asynchronous stations in complex battlefield networks, and to provide an asynchronous station sorting method based on the arrival time of frequency hopping signals.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] An asynchronous network station sorting method based on the arrival time of frequency hopping signals includes the following steps:

[0009] S1, a set of descriptors for the same hopping rate after cache classification;

[0010] S2, Precisely estimate the frequency hopping period;

[0011] S3. After analysis, the starting point of the frequency hopping sequence is obtained;

[0012] S4. Based on the frequency hopping period obtained in S2 and the starting point of the frequency hopping sequence obtained in S3, a preliminary set of network station frequency hopping signals that meet the conditions is obtained.

[0013] S5, Correction network station frequency set;

[0014] S6. Output the network station results.

[0015] Preferably, the frequency hopping descriptor in step S1 includes the frequency, dwell time, arrival time, and power of the frequency hopping signal; the same hopping rate means that the number of carrier frequency changes of the radio station per unit time is the same; step S1 includes the following steps:

[0016] S11. Determine whether multiple network stations have the same hopping speed based on the dwell time of the frequency hopping signal. The reciprocal of the hopping speed is the frequency hopping period. The frequency hopping period is linearly related to the dwell time of the frequency hopping signal. When the dwell time of the frequency hopping signal is the same or very close, they are considered to be network stations with the same hopping speed.

[0017] S12. Buffer the frequency hopping signals of multiple stations with the same hopping speed.

[0018] Preferably, step S2 includes the following steps:

[0019] S21. Set a parameter m_Threshold as the threshold value for calculating the period of the frequency hopping signal. Roughly estimate the hopping rate based on the dwell time. Set m_Threshold to one-tenth of the estimated hopping rate. Traverse the set. If there are m_Threshold consecutive frequency hopping signals in the set, then the set is a valid frequency hopping set, and proceed to step S22; otherwise, the set is an invalid frequency hopping set, and exit the algorithm.

[0020] S22. The time SumPeriod for the statistical m_Threshold frequency hopping signals is used as the initial frequency hopping period. The accurate frequency hopping period nPeriod is obtained by using the formula nPeriod=(Sum_period+m_Threshold / 2) / m_Threshold.

[0021] Preferably, the accurate hopping rate is obtained based on the calculated accurate hopping period nPeriod, and the value of m_Threshold is corrected based on the accurate hopping rate.

[0022] Preferably, step S3 includes the following steps:

[0023] S31. Set a parameter TimeThreshold as the time threshold for obtaining the starting point of the frequency hopping sequence. Select the frequency hopping signal of a certain radio station. Based on the frequency hopping period nPeriod obtained in step S21, combined with the arrival time Apear of the frequency hopping signal and the time threshold TimeThreshold, calculate the ideal arrival time of the next frequency hopping signal of this radio station. Determine whether the arrival time of the next frequency hopping signal meets the ideal arrival time. If yes, proceed to step S32; if no, continue searching until the set is traversed.

[0024] S32. Determine whether more than m_Threshold consecutive frequency hopping signals can be found for this network station. If the determination is yes, then the signal is the starting point of the frequency hopping sequence, and proceed to step S4; if the determination is no, proceed to step S31.

[0025] Preferably, step S4 includes the following steps:

[0026] S41. Based on the arrival time Apear of the frequency hopping start sequence found in step S31, and combined with the calculated ideal arrival time of the next frequency hopping signal of a certain network station, select the frequency hopping descriptor that meets the conditions, and execute step S42.

[0027] S42. If a missing frequency hopping occurs, determine whether the number of missing frequency hopping is greater than the threshold value m_Threshold. If the determination is yes, exit step S4 and execute step S31 to find another network station; if the determination is no, execute step S41.

[0028] Repeat steps S41 to S42 until the set is traversed, obtain the frequency hopping signal of the network station that meets the condition, and execute step S5.

[0029] Preferably, step S5 includes the following steps:

[0030] S51. Based on the set of network station frequency hopping signals obtained in step S4, first reorder the frequency set in ascending order of frequency, calculate the total average frequency and the average frequency of each frequency band, select frequencies with a frequency greater than half of the average to form a new set of network station frequency hopping signals, and execute S52.

[0031] S52. Perform forward differencing on the frequencies in the set and statistically analyze the frequency difference distribution. If the probability of a certain difference FreqDifference is greater than 70%, proceed to step S53; otherwise, proceed to step S54.

[0032] S53. Find the frequencies in the set where the frequency difference between the first FirstFreq and the last EndFreq is equal to the FreqDifference. Using FreqDifference as the common difference and the bandwidth BandWidth = (EndFreq - FirstFreq), correct the frequency set to generate a new arithmetic frequency set.

[0033] S54, output according to the original frequency set.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] First, the method boasts high precision. It utilizes the arrival time characteristics of frequency-hopping signals for sorting, with the accuracy typically reaching the nanosecond level. Furthermore, the method employs a preliminary acquisition of the network station frequency-hopping signal set to coarsely classify the network stations, followed by a finer subdivision through "correcting the network station frequency set," thereby enhancing the sorting accuracy.

[0036] Second, it has strong stability. Since the arrival time of the frequency hopping signal is one of the most basic parameters of the frequency hopping signal, this method has strong stability and is applicable to different frequency hopping signals.

[0037] Third, it has good real-time performance. The arrival time of the frequency hopping signal is obtained in real time during the frequency hopping signal reception process, so the method has good real-time performance.

[0038] Fourth, the computational load is low. This method only needs to estimate the frequency hopping period and the starting point of the hopping sequence to obtain the frequency hopping signal set of each network station, resulting in a relatively low computational load. Other methods may require signal preprocessing, analysis, and processing, leading to a larger computational load.

[0039] In comparison, blind source separation methods require multiple receivers to receive signals and perform blind source separation on the received signals. This incurs relatively high hardware and computational costs, and the sorting effect is poor when the number of signal sources is large. Network station sorting methods based on other frequency-hopping signal characteristic parameters require selecting appropriate frequency-hopping signal characteristic parameters and processing and choosing them appropriately. Therefore, the algorithm requirements are high, and the sorting effect is limited by the selected parameters. When performing multi-network station sorting, the more networks there are, the less ideal the sorting effect becomes based on other frequency-hopping signal characteristic parameters. In contrast, frequency-hopping signal arrival time-based sorting methods offer advantages such as high accuracy, strong stability, good real-time performance, and low computational cost. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the asynchronous network station sorting method based on the arrival time of frequency hopping signals according to the present invention. Detailed Implementation

[0041] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined in this application.

[0042] like Figure 1 As shown, this embodiment provides an asynchronous network station sorting method based on the arrival time of frequency hopping signals, specifically including:

[0043] S1, a set of descriptors for the same hopping rate after cache classification;

[0044] S2, Precisely estimate the frequency hopping period;

[0045] S3. After analysis, the starting point of the frequency hopping sequence is obtained;

[0046] S4. Based on the frequency hopping period obtained in S2 and the starting point of the frequency hopping sequence obtained in S3, a preliminary set of network station frequency hopping signals that meet the conditions is obtained.

[0047] S5, Correction network station frequency set;

[0048] S6. Output the network station results.

[0049] In this embodiment, the frequency hopping descriptor in step S1 includes the frequency, dwell time, arrival time, and power of the frequency hopping signal; the same hopping rate means that the number of carrier frequency changes of the radio station per unit time is the same; step S1 specifically includes:

[0050] S11. Determine whether multiple network stations have the same hopping speed based on the dwell time of the frequency hopping signal. The reciprocal of the hopping speed is the frequency hopping period. The frequency hopping period is linearly related to the dwell time of the frequency hopping signal. Therefore, when the dwell times of the frequency hopping signals are the same or very close, they are considered to be network stations with the same hopping speed (because the actual environment is complex and the signal will be affected, when the dwell times of the frequency hopping signals are very close, they are also considered to be network stations with the same hopping speed).

[0051] S12. Buffer the frequency hopping signals of multiple stations with the same hopping speed.

[0052] In this embodiment, step S2 specifically includes:

[0053] S21. Set a parameter m_Threshold as the threshold value for calculating the period of the frequency hopping signal. Roughly estimate the hopping rate based on the dwell time. Set m_Threshold to one-tenth of the estimated hopping rate. Traverse the set. If there are m_Threshold consecutive frequency hopping signals in the set, then the set is a valid frequency hopping set, and proceed to step S22; otherwise, the set is an invalid frequency hopping set, and exit the algorithm.

[0054] S22. The time SumPeriod for the statistical m_Threshold frequency hopping signals is used as the initial frequency hopping period. The accurate frequency hopping period nPeriod is obtained by using the formula nPeriod=(Sum_period+m_Threshold / 2) / m_Threshold.

[0055] Based on the calculated accurate frequency hopping period nPeriod, the accurate hopping rate is obtained, and the value of m_Threshold is corrected according to the accurate hopping rate.

[0056] In this embodiment, step S3 specifically includes:

[0057] S31. Set a parameter TimeThreshold as the time threshold for obtaining the starting point of the frequency hopping sequence. TimeThreshold is related to the time resolution, but it should be analyzed on a case-by-case basis. Select the frequency hopping signal of a certain station. Based on the frequency hopping period nPeriod obtained in step S21, combined with the arrival time Apear of the frequency hopping signal and the time threshold TimeThreshold, calculate the ideal arrival time of the next frequency hopping signal of this station. Determine whether the arrival time of the next frequency hopping signal meets the ideal arrival time. If yes, proceed to step S32; if no, continue searching until the set is traversed.

[0058] S32. Determine whether more than m_Threshold consecutive frequency hopping signals can be found for this network station. If the determination is yes, then the signal is the starting point of the frequency hopping sequence, and proceed to step S4; if the determination is no, proceed to step S31.

[0059] In this embodiment, step S4 specifically includes:

[0060] S41. Based on the arrival time Apear of the frequency hopping start sequence found in step S31, and combined with the calculated ideal arrival time of the next frequency hopping signal of a certain network station, select the frequency hopping descriptor that meets the conditions, and execute step S42.

[0061] S42. If a missing frequency hopping occurs, determine whether the number of missing frequency hopping is greater than the threshold value m_Threshold. If the determination is yes, exit step S4 and execute step S31 to find another network station; if the determination is no, execute step S41. The hopping rate is the reciprocal of the frequency hopping period, which has been obtained in step S2.

[0062] Repeat steps S41 to S42 until the set is traversed, obtain the frequency hopping signal of the network station that meets the condition, and execute step S5.

[0063] In this embodiment, step S5 specifically includes:

[0064] S51. Based on the set of network station frequency hopping signals obtained in step S4, first reorder the frequency set in ascending order of frequency, calculate the total average frequency and the average frequency of each frequency band, select frequencies with a frequency greater than half of the average to form a new set of network station frequency hopping signals, and execute S52.

[0065] S52. Perform forward differencing on the frequencies in the set and statistically analyze the frequency difference distribution. If the probability of a certain difference FreqDifference is greater than 70%, proceed to step S53; otherwise, proceed to step S54.

[0066] S53. Find the frequencies in the set where the frequency difference between the first FirstFreq and the last EndFreq is equal to the FreqDifference. Using FreqDifference as the common difference and the bandwidth BandWidth = (EndFreq - FirstFreq), correct the frequency set to generate a new arithmetic frequency set.

[0067] S54, output according to the original frequency set.

[0068] In this embodiment, step S6 specifically involves: traversing the set, finding all network stations, correcting the frequency set of the network stations, and finally outputting the corrected frequency set, thus completing the network station sorting.

[0069] Based on the above, the asynchronous network station sorting method based on the arrival time of frequency hopping signals in this embodiment can utilize the characteristics of the arrival time of frequency hopping signals for sorting, with the accuracy of the arrival time typically reaching the nanosecond level. Furthermore, the method uses "preliminary acquisition of the network station frequency hopping signal set" to coarsely classify the network stations, and then "correction of the network station frequency set" to further refine the frequency set, improving sorting accuracy. Since the arrival time of the frequency hopping signal is one of the most fundamental parameters of frequency hopping signals, this method has strong stability and is applicable to different frequency hopping signals. The arrival time of the frequency hopping signal is acquired in real time during the frequency hopping signal reception process, thus the method has excellent real-time performance. This method only needs to estimate the frequency hopping period and the starting point of the hopping sequence to obtain the frequency hopping signal set of each network station, resulting in relatively low computational complexity. Other methods may require signal preprocessing, analysis, and processing, leading to higher computational costs.

Claims

1. An asynchronous network station sorting method based on the arrival time of frequency hopping signals, characterized in that, Includes the following steps: S1, a set of descriptors for the same hopping rate after cache classification; S2, Precisely estimate the frequency hopping period; Step S2 includes the following steps: S21. Set a parameter m_Threshold as the threshold value for calculating the period of the frequency hopping signal. Roughly estimate the hopping rate based on the dwell time. Set m_Threshold to one-tenth of the estimated hopping rate. Traverse the set. If there are m_Threshold consecutive frequency hopping signals in the set, then the set is a valid frequency hopping set, and proceed to step S22; otherwise, the set is an invalid frequency hopping set, and exit the algorithm. S22. The time SumPeriod for m_Threshold frequency hopping signals is used as the initial frequency hopping period. The accurate frequency hopping period nPeriod is obtained by using the formula nPeriod=(Sum_period + m_Threshold / 2) / m_Threshold. S3. After analysis, the starting point of the frequency hopping sequence is obtained; Step S3 includes the following steps: S31. Set a parameter TimeThreshold as the time threshold for obtaining the starting point of the frequency hopping sequence. Select the frequency hopping signal of a certain radio station. Based on the frequency hopping period nPeriod obtained in step S21, combined with the arrival time Apear of the frequency hopping signal and the time threshold TimeThreshold, calculate the ideal arrival time of the next frequency hopping signal of this radio station. Determine whether the arrival time of the next frequency hopping signal meets the ideal arrival time. If yes, proceed to step S32; if no, continue searching until the set is traversed. S32. Determine whether more than m_Threshold consecutive frequency hopping signals can be found for this network station. If the determination is yes, then the signal is the starting point of the frequency hopping sequence, and proceed to step S4; if the determination is no, proceed to step S31. S4. Based on the frequency hopping period obtained in S2 and the starting point of the frequency hopping sequence obtained in S3, a preliminary set of network station frequency hopping signals that meet the conditions is obtained. Step S4 includes the following steps: S41. Based on the arrival time Apear of the frequency hopping start sequence found in step S31, and combined with the calculated ideal arrival time of the next frequency hopping signal of a certain network station, select the frequency hopping descriptor that meets the conditions, and execute step S42. S42. If missing frequency hopping occurs, determine if the number of missing frequency hopping instances is greater than m_Threshold. If the threshold value is true, exit step S4 and proceed to step S31 to find another network station; if the threshold value is false, proceed to step S41. Repeat steps S41~S42 until the set is traversed, obtain the frequency hopping signal of the network station that meets the condition, and execute step S5; S5, Correction network station frequency set; S6. Output the network station results.

2. The asynchronous network station sorting method based on frequency hopping signal arrival time according to claim 1, Its features are, The frequency hopping descriptor in step S1 includes the frequency, dwell time, arrival time, and power of the frequency hopping signal; the same hopping rate means that the number of carrier frequency changes of the radio station per unit time is the same; step S1 includes the following steps: S11. Determine whether multiple network stations have the same hopping speed based on the dwell time of the frequency hopping signal. The reciprocal of the hopping speed is the frequency hopping period. The frequency hopping period is linearly related to the dwell time of the frequency hopping signal. When the dwell time of the frequency hopping signal is the same or very close, they are considered to be network stations with the same hopping speed. S12. Buffer the frequency hopping signals of multiple stations with the same hopping speed.

3. The asynchronous network station sorting method based on the arrival time of frequency hopping signals according to claim 1, Its features are, Based on the calculated accurate frequency hopping period nPeriod, the accurate hopping rate is obtained, and the value of m_Threshold is corrected based on the accurate hopping rate.

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