Underwater acoustic communication signal detection method, device and equipment and readable storage medium
By detecting synchronous signals in water acoustic communication and using training sequences for Doppler search and compensation, combined with relevant detection, the problem of false signal interference is solved, and the accuracy and system robustness of water acoustic communication signal detection are improved.
Patent Information
- Application Number
- CN202411416698.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-11
- Publication Date
- 2024-12-31
AI Technical Summary
Existing water acoustic communication methods are susceptible to false signals in complex and changeable water acoustic channels, resulting in false alarm detection of synchronous signal and affecting the performance of the communication system.
Determine the starting position of the frame signal by detecting the synchronization signal, intercept the sequence to be measured and the sub-sequence to be measured, use the replica of the training sequence to be searched and compensated, combine the relevant detection to determine whether the signal is a cooperative communication signal, set the Doppler factor and Related peak thresholds to exclude false signal interference.
It improves the accuracy of water acoustic communication signal detection, reduces the probability of false alarms, and improves the robustness of the communication system.
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Figure CN119232277A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of underwater acoustic wireless communication, and in particular to an underwater acoustic communication signal detection method, device, equipment and readable storage medium. Background Art
[0002] Underwater acoustic communication is the only known wireless technology that can exchange information underwater over long distances. It is not only the preferred communication method in the military field, but also widely used in the civilian field. However, underwater acoustic communication faces more complex and changeable problems than wireless communication in the air, especially the more complex problems of large delay and fast Doppler expansion. The implementation process of underwater acoustic communication methods generally includes key steps such as signal detection and synchronization, channel estimation and equalization. Among them, the correct detection of cooperative communication signals is the prerequisite for the subsequent high-quality decoding / decoding of communications.
[0003] The frame structure of commonly used underwater acoustic communication includes synchronization signal, protection gap, training sequence and information sequence. The existing underwater acoustic communication method determines the presence or absence of cooperative communication signal by real-time detection of whether the synchronization signal arrives. Although the synchronization signal has good matching correlation performance, in actual application, there are a large number of false signals in the complex and changeable underwater acoustic channel, which interfere with the synchronization signal detection and cause false alarms, occupy the limited computing resources of the equipment, cause the cooperative communication signal to be missed when it arrives, and greatly reduce the performance of the communication system. Summary of the invention
[0004] The present application provides a method, device, equipment and readable storage medium for underwater acoustic communication signal detection, which can solve the technical problem in the prior art that signal detection is easily interfered by false signals.
[0005] In a first aspect, an embodiment of the present application provides a method for detecting an underwater acoustic communication signal, the method comprising:
[0006] Determine the starting position of the current frame signal according to the detection of the synchronization signal, intercept the sequence to be tested according to the starting position of the current frame signal and the position of the training sequence in the cooperative communication signal, and intercept the subsequence to be tested from the sequence to be tested, wherein when the current frame signal is a cooperative communication signal, the sequence to be tested includes the training sequence;
[0007] Performing Doppler search on the sequence to be tested according to the copy of the training sequence to obtain a first Doppler factor, performing Doppler compensation on the sequence to be tested according to the first Doppler factor to obtain a first compensation sequence, and performing correlation detection on the first compensation sequence and the copy of the training sequence to obtain a first correlation peak value and its position;
[0008] Performing Doppler search on the subsequence to be tested according to the copy of the training sequence to obtain a second Doppler factor, performing Doppler compensation on the subsequence to be tested according to the second Doppler factor to obtain a second compensation sequence, and performing correlation detection on the second compensation sequence and the copy of the training sequence to obtain a second correlation peak value and its position;
[0009] If the absolute value of the difference between the first Doppler factor and the second Doppler factor is less than or equal to the first threshold, the first correlation peak and the second correlation peak are both greater than or equal to the second threshold, and the absolute value of the difference between the position interval of the first correlation peak and the second correlation peak and the starting position interval of the sequence to be tested and the subsequence to be tested is less than or equal to the third threshold, then the current frame signal is determined to be a cooperative communication signal.
[0010] Furthermore, in one embodiment, the training sequence copy includes a non-Doppler copy and a plurality of Doppler copies, the non-Doppler copy is used for correlation detection with the first compensation sequence and the second compensation sequence, the Doppler copy is used for Doppler search of the sequence to be tested and the subsequence to be tested, and each Doppler copy corresponds to a Doppler factor;
[0011] The step of performing Doppler search on the sequence to be tested according to the training sequence copy to obtain the first Doppler factor comprises:
[0012] Perform correlation detection on the sequence to be tested and each Doppler replica respectively, and determine the Doppler factor corresponding to the Doppler replica with the largest correlation peak as the first Doppler factor;
[0013] The step of performing Doppler search on the subsequence to be tested according to the training sequence copy to obtain a second Doppler factor comprises:
[0014] The subsequence to be tested is respectively correlated with each Doppler replica, and the Doppler factor corresponding to the Doppler replica with the largest correlation peak is determined as the second Doppler factor.
[0015] Furthermore, in one embodiment, the Doppler factor is equal to the ratio of the relative motion speed to the speed of sound in water, and the relative motion speeds corresponding to all Doppler copies are in an arithmetic progression.
[0016] Furthermore, in one embodiment, the step of determining the starting position of the current frame signal according to the synchronization signal detection situation includes:
[0017] The preprocessed received signal and the synchronization signal copy are subjected to real-time double-window sliding correlation detection, and whether the synchronization signal is detected is determined based on the correlation value between the received signal and the synchronization signal copy in the two sliding windows. When the synchronization signal is detected, the starting position of the synchronization signal is determined as the starting position of the current frame signal.
[0018] Further, in one embodiment, the step of performing correlation detection on the first compensation sequence and the training sequence replica to obtain a first correlation peak and its position includes:
[0019] Performing correlation detection on the first compensation sequence and the training sequence copy in the frequency domain to obtain a first correlation function, and converting the first correlation function from the frequency domain to the time domain to obtain a first correlation peak and its position;
[0020] The step of performing correlation detection on the second compensation sequence and the training sequence copy to obtain a second correlation peak and its position comprises:
[0021] The second compensation sequence is correlated with the training sequence copy in the frequency domain to obtain a second correlation function, and the second correlation function is converted from the frequency domain to the time domain to obtain a second correlation peak and its position.
[0022] Furthermore, in one embodiment, the first compensation sequence, the second compensation sequence and the training sequence copy are converted from the time domain to the frequency domain by fast Fourier transform, and the first correlation function and the second correlation function are converted from the frequency domain to the time domain by fast inverse Fourier transform.
[0023] Furthermore, in one embodiment, the step of extracting a subsequence to be tested from the sequence to be tested includes:
[0024] The sequence to be tested is divided into K sub-signal segments, and L consecutive sub-signal segments are extracted from the sub-sequence to be tested, wherein K>L>1.
[0025] In a second aspect, an embodiment of the present application further provides an underwater acoustic communication signal detection device, the underwater acoustic communication signal detection device comprising:
[0026] An interception module, used to determine the starting position of the current frame signal according to the detection of the synchronization signal, intercept the sequence to be tested according to the starting position of the current frame signal and the position of the training sequence in the cooperative communication signal, and intercept the subsequence to be tested from the sequence to be tested, wherein when the current frame signal is a cooperative communication signal, the sequence to be tested includes the training sequence;
[0027] A first processing module is used to perform Doppler search on the sequence to be tested according to the training sequence copy to obtain a first Doppler factor, perform Doppler compensation on the sequence to be tested according to the first Doppler factor to obtain a first compensation sequence, and perform correlation detection on the first compensation sequence and the training sequence copy to obtain a first correlation peak value and its position;
[0028] A second processing module is used to perform Doppler search on the subsequence to be tested according to the copy of the training sequence to obtain a second Doppler factor, perform Doppler compensation on the subsequence to be tested according to the second Doppler factor to obtain a second compensation sequence, and perform correlation detection on the second compensation sequence and the copy of the training sequence to obtain a second correlation peak value and its position;
[0029] A judgment module is used to determine that the current frame signal is a cooperative communication signal if the absolute value of the difference between the first Doppler factor and the second Doppler factor is less than or equal to the first threshold, the first correlation peak value and the second correlation peak value are both greater than or equal to the second threshold, and the absolute value of the difference between the position interval of the first correlation peak value and the second correlation peak value and the starting position interval of the sequence to be tested and the subsequence to be tested is less than or equal to a third threshold.
[0030] In a third aspect, an embodiment of the present application also provides an underwater acoustic communication signal detection device, which includes a processor, a memory, and an underwater acoustic communication signal detection program stored in the memory and executable by the processor, wherein when the underwater acoustic communication signal detection program is executed by the processor, the steps of the above-mentioned underwater acoustic communication signal detection method are implemented.
[0031] In a fourth aspect, an embodiment of the present application further provides a readable storage medium, on which a program for detecting an underwater acoustic communication signal is stored, wherein when the program for detecting an underwater acoustic communication signal is executed by a processor, the steps of the above-mentioned method for detecting an underwater acoustic communication signal are implemented.
[0032] In the present application, the starting position of the current frame signal is determined by detecting the synchronization signal, the sequence to be tested and the subsequence to be tested are intercepted from the current frame signal, Doppler search, Doppler compensation and correlation detection are performed on the sequence to be tested and the subsequence to be tested respectively according to the copy of the training sequence, and the Doppler factor, the size of the correlation peak and the position of the correlation peak are used to determine whether the current frame signal is a cooperative communication signal. Through the present application, the training sequence information is mined and utilized on the basis of the synchronization signal detection, the detection accuracy is improved through multi-level detection and judgment, and the interference of false signals is eliminated, which can effectively reduce the false alarm probability of the underwater acoustic communication signal and improve the robustness of the communication system. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 This is a flow chart of a method for detecting underwater acoustic communication signals in one embodiment of the present application;
[0034] Figure 2 A schematic diagram of the relationship between the sequence to be tested and the training sequence in an embodiment of the present application;
[0035] Figure 3 This is a flow chart of a method for detecting underwater acoustic communication signals in another embodiment of the present application;
[0036] Figure 4 This is a schematic diagram of the functional modules of an underwater acoustic communication signal detection device in one embodiment of the present application;
[0037] Figure 5 This is a schematic diagram of the hardware structure of the underwater acoustic communication signal detection equipment involved in the embodiment of the present application. DETAILED DESCRIPTION
[0038] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0039] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.
[0040] In a first aspect, an embodiment of the present application provides a method for detecting underwater acoustic communication signals.
[0041] Figure 1 A flow chart of a method for detecting underwater acoustic communication signals in one embodiment of the present application is shown.
[0042] Reference Figure 1 In one embodiment, the underwater acoustic communication signal detection method includes the following steps:
[0043] S11. Determine the starting position of the current frame signal according to the detection of the synchronization signal, intercept the sequence to be tested according to the starting position of the current frame signal and the position of the training sequence in the cooperative communication signal, and intercept the subsequence to be tested from the sequence to be tested, wherein, when the current frame signal is a cooperative communication signal, the sequence to be tested includes the training sequence.
[0044] Specifically, the frame structure of underwater acoustic communication includes a synchronization signal, a protection gap, a training sequence, and an information sequence. The synchronization signal is located at the beginning of the frame signal, and its function is to enable the receiving end to quickly and accurately determine the starting position of the frame signal, thereby achieving time synchronization and frequency synchronization. The protection gap is set after the synchronization signal to avoid the interference of the tail of the previous frame signal on the current frame signal, and also to provide a certain buffer time for the processing of the receiving end. The training sequence follows the protection gap and is used by the receiving end to perform operations such as channel estimation, equalization parameter adjustment, and synchronization adjustment to prepare for the correct reception of the information sequence. Finally, there is the information sequence, which carries the actual user data or control information to be transmitted and is the core content of the frame signal.
[0045] Before the formal start of underwater acoustic communication, the transmitter and receiver need to agree on the setting method of the synchronization signal, protection interval and training sequence so that the receiver can detect the synchronization signal and training sequence from the received signal and decode the information sequence.
[0046] Optionally, the synchronization signal adopts a linear frequency modulation signal or a hyperbolic frequency modulation signal, and the training sequence adopts a spread spectrum sequence.
[0047] In this embodiment, the presence of a synchronization signal in the current frame signal does not mean that the current frame signal is a cooperative communication signal. Instead, a test sequence corresponding to the position of the training sequence is intercepted from the current frame signal for detection to detect whether the test sequence contains the training sequence. If so, the current frame signal is considered to be a cooperative communication signal, and the information sequence is decoded.
[0048] Figure 2 A schematic diagram showing the relationship between the sequence to be tested and the training sequence in an embodiment of the present application is shown.
[0049] Reference Figure 2 , the interval between the starting position of the sequence to be tested and the starting position of the current frame signal is less than or equal to the interval between the starting position of the training sequence and the starting position of the cooperative communication signal, and the interval between the ending position of the sequence to be tested and the starting position of the current frame signal is greater than or equal to the interval between the ending position of the training sequence and the starting position of the cooperative communication signal.
[0050] For example, the step of extracting a subsequence to be tested from the sequence to be tested includes:
[0051] The sequence to be tested is divided into K sub-signal segments, and L consecutive sub-signal segments are extracted from the sub-sequence to be tested, wherein K>L>1.
[0052] S12, performing Doppler search on the test sequence according to the training sequence copy to obtain a first Doppler factor, performing Doppler compensation on the test sequence according to the first Doppler factor to obtain a first compensation sequence, and performing correlation detection on the first compensation sequence and the training sequence copy to obtain a first correlation peak value and its position.
[0053] The Doppler effect is a frequency change of waves caused by relative motion between the signal source and the receiver. Doppler search is used to determine the Doppler shift value in the received signal in order to compensate and process the signal. The Doppler factor is used to describe the Doppler shift size. Doppler compensation is used to correct the frequency offset caused by the Doppler effect. Correlation detection determines the similarity or correlation between two signals by calculating the correlation function of them. If two signals are similar, then their correlation function will have a peak at a certain time delay.
[0054] In this embodiment, Doppler search, Doppler compensation and correlation detection are performed on the sequence to be tested based on the training sequence copy to obtain a first Doppler factor, a first correlation peak value and its position as a basis for subsequent determination of whether the sequence to be tested contains the training sequence.
[0055] S13, performing Doppler search on the subsequence to be measured according to the training sequence copy to obtain a second Doppler factor, performing Doppler compensation on the subsequence to be measured according to the second Doppler factor to obtain a second compensation sequence, and performing correlation detection on the second compensation sequence and the training sequence copy to obtain a second correlation peak value and its position.
[0056] In this embodiment, Doppler search, Doppler compensation and correlation detection are performed on the subsequence to be tested based on the training sequence copy to obtain a second Doppler factor, a second correlation peak value and its position as a basis for subsequent determination of whether the sequence to be tested contains the training sequence.
[0057] S14. If the absolute value of the difference between the first Doppler factor and the second Doppler factor is less than or equal to the first threshold, the first correlation peak and the second correlation peak are both greater than or equal to the second threshold, and the absolute value of the difference between the position interval between the first correlation peak and the second correlation peak and the starting position interval of the sequence to be measured and the subsequence to be measured is less than or equal to the third threshold, then it is determined that the current frame signal is a cooperative communication signal.
[0058] In this embodiment, when the sequence to be tested includes a training sequence, within a training sequence, the Doppler frequency shift of the real signal is substantially consistent, and the compensated sequence to be tested and the subsequence to be tested can both find highly correlated parts in the training sequence copy, and the relative position relationship of the two parts is substantially consistent with the relative position relationship of the sequence to be tested and the subsequence to be tested. Thus, three judgment dimensions can be determined, namely, judging the difference between the first Doppler factor and the second Doppler factor, judging the size of the first correlation peak and the second correlation peak, and judging the position interval of the first correlation peak and the second correlation peak.
[0059] Therefore, in this embodiment, the starting position of the current frame signal is determined by detecting the synchronization signal, the sequence to be tested and the subsequence to be tested are intercepted from the current frame signal, Doppler search, Doppler compensation and correlation detection are performed on the sequence to be tested and the subsequence to be tested respectively according to the copy of the training sequence, and the Doppler factor, the size of the correlation peak and the position of the correlation peak are used to determine whether the current frame signal is a cooperative communication signal. Through this embodiment, the training sequence information is mined and utilized on the basis of the synchronization signal detection, the detection accuracy is improved through multi-level detection and judgment, and the interference of false signals is eliminated, which can effectively reduce the false alarm probability of the underwater acoustic communication signal and improve the robustness of the communication system.
[0060] Figure 3 A flow chart of a method for detecting underwater acoustic communication signals in another embodiment of the present application is shown.
[0061] Reference Figure 3, further, in one embodiment, the training sequence copy includes a non-Doppler copy and a plurality of Doppler copies, the non-Doppler copy is used for correlation detection with the first compensation sequence and the second compensation sequence, the Doppler copy is used for Doppler search of the sequence to be tested and the subsequence to be tested, and each Doppler copy corresponds to a Doppler factor;
[0062] The step of performing Doppler search on the sequence to be tested according to the training sequence copy to obtain the first Doppler factor comprises:
[0063] Perform correlation detection on the sequence to be tested and each Doppler replica respectively, and determine the Doppler factor corresponding to the Doppler replica with the largest correlation peak as the first Doppler factor;
[0064] The step of performing Doppler search on the subsequence to be tested according to the training sequence copy to obtain a second Doppler factor comprises:
[0065] The subsequence to be tested is respectively correlated with each Doppler replica, and the Doppler factor corresponding to the Doppler replica with the largest correlation peak is determined as the second Doppler factor.
[0066] In this embodiment, multiple Doppler copies of the training sequence are generated in advance, and Doppler search is implemented by performing correlation detection with the help of the multiple Doppler copies, thereby improving processing efficiency.
[0067] Furthermore, in one embodiment, the Doppler factor is equal to the ratio of the relative motion speed to the speed of sound in water, and the relative motion speeds corresponding to all Doppler copies are in an arithmetic progression.
[0068] In this embodiment, evenly distributed discrete Doppler factors are obtained through evenly distributed discrete relative motion velocities, thereby improving processing accuracy.
[0069] For example, let s(t 0 ) is the baseband signal of the training sequence, f c If the carrier frequency is the passband signal without Doppler effect, Assuming multiple relative motion speeds as V = [-v:m:v], m is the discrete interval, then the corresponding Doppler factor is σ = V / c, c is the speed of sound in water, then the corresponding Doppler effect passband signal is The Doppler replica of the training sequence is obtained after down-converting to baseband.
[0070] Furthermore, in one embodiment, the step of determining the starting position of the current frame signal according to the synchronization signal detection situation includes:
[0071] The preprocessed received signal and the synchronization signal copy are subjected to real-time double-window sliding correlation detection, and whether the synchronization signal is detected is determined based on the correlation value between the received signal and the synchronization signal copy in the two sliding windows. When the synchronization signal is detected, the starting position of the synchronization signal is determined as the starting position of the current frame signal.
[0072] Specifically, the preprocessing operation is used to convert the received signal from a passband signal to a baseband signal. In the real-time dual-window sliding correlation detection, two sliding windows are set. The selection of the window size needs to consider the length of the synchronization signal and the characteristics of the signal. Generally, it should be able to completely cover the length of the synchronization signal. At the same time, the calculation efficiency should also be taken into account. The two sliding windows are gradually slid on the received signal, sliding one sampling point or a fixed step size each time. For each window position, the correlation value of the received signal and the copy of the synchronization signal in the sliding window is calculated. If the correlation value of the rear window is significantly greater than the correlation value of the front window, it means that the position of the synchronization signal may be approaching. Continue to slide the window and calculate the correlation value, and observe the changing trend of the correlation value. When the correlation value rises rapidly and reaches a peak value, it is likely that it has approached or reached the position of the synchronization signal. The accurate position of the synchronization signal can be determined by checking the distribution of correlation values around the peak value and comparing it with a preset threshold.
[0073] In this embodiment, the synchronization signal is detected by real-time dual-window sliding correlation, which helps to enhance anti-interference, improve detection accuracy, and adapt to signal changes.
[0074] Further, in one embodiment, the step of performing correlation detection on the first compensation sequence and the training sequence replica to obtain a first correlation peak and its position includes:
[0075] Performing correlation detection on the first compensation sequence and the training sequence copy in the frequency domain to obtain a first correlation function, and converting the first correlation function from the frequency domain to the time domain to obtain a first correlation peak and its position;
[0076] The step of performing correlation detection on the second compensation sequence and the training sequence copy to obtain a second correlation peak and its position comprises:
[0077] The second compensation sequence is correlated with the training sequence copy in the frequency domain to obtain a second correlation function, and the second correlation function is converted from the frequency domain to the time domain to obtain a second correlation peak and its position.
[0078] In this embodiment, the calculation efficiency is improved by performing correlation detection in the frequency domain and then converting the correlation function back to the time domain.
[0079] Furthermore, in one embodiment, the first compensation sequence, the second compensation sequence and the training sequence copy are converted from the time domain to the frequency domain by fast Fourier transform, and the first correlation function and the second correlation function are converted from the frequency domain to the time domain by fast inverse Fourier transform.
[0080] In this embodiment, time-frequency conversion is performed by fast Fourier transform and fast inverse Fourier transform, thereby further improving calculation efficiency.
[0081] For example, the compensation sequence and the training sequence copy are doubled in number, that is, 2L data The fast Fourier transform of the compensation sequence is obtained by Y(jw) and the training sequence copy is obtained by Y 0 (jw), perform correlation detection, and then perform fast inverse Fourier transform to convert the correlation function back to the time domain.
[0082] In a second aspect, an embodiment of the present application also provides an underwater acoustic communication signal detection device.
[0083] Figure 4 A schematic diagram of the functional modules of an underwater acoustic communication signal detection device in an embodiment of the present application is shown.
[0084] Reference Figure 4 In one embodiment, the underwater acoustic communication signal detection device includes:
[0085] The interception module 10 is used to determine the starting position of the current frame signal according to the detection of the synchronization signal, intercept the sequence to be tested according to the starting position of the current frame signal and the position of the training sequence in the cooperative communication signal, and intercept the subsequence to be tested from the sequence to be tested, wherein when the current frame signal is a cooperative communication signal, the sequence to be tested includes the training sequence;
[0086] A first processing module 20 is configured to perform Doppler search on a test sequence according to a copy of the training sequence to obtain a first Doppler factor, perform Doppler compensation on the test sequence according to the first Doppler factor to obtain a first compensation sequence, and perform correlation detection on the first compensation sequence and the copy of the training sequence to obtain a first correlation peak value and its position;
[0087] The second processing module 30 is used to perform Doppler search on the subsequence to be tested according to the copy of the training sequence to obtain a second Doppler factor, perform Doppler compensation on the subsequence to be tested according to the second Doppler factor to obtain a second compensation sequence, and perform correlation detection on the second compensation sequence and the copy of the training sequence to obtain a second correlation peak value and its position;
[0088] The judgment module 40 is used to determine that the current frame signal is a cooperative communication signal if the absolute value of the difference between the first Doppler factor and the second Doppler factor is less than or equal to the first threshold, the first correlation peak value and the second correlation peak value are both greater than or equal to the second threshold, and the absolute value of the difference between the position interval of the first correlation peak value and the second correlation peak value and the starting position interval of the sequence to be tested and the subsequence to be tested is less than or equal to the third threshold.
[0089] Furthermore, in one embodiment, the training sequence copy includes a non-Doppler copy and a plurality of Doppler copies, the non-Doppler copy is used for correlation detection with the first compensation sequence and the second compensation sequence, the Doppler copy is used for Doppler search of the sequence to be tested and the subsequence to be tested, and each Doppler copy corresponds to a Doppler factor;
[0090] The first processing module 20 is used to perform correlation detection on the sequence to be tested and each Doppler replica respectively, and determine the Doppler factor corresponding to the Doppler replica with the largest correlation peak as the first Doppler factor;
[0091] The second processing module 30 is used to perform correlation detection on the subsequence to be detected and each Doppler replica respectively, and determine the Doppler factor corresponding to the Doppler replica with the largest correlation peak as the second Doppler factor.
[0092] Furthermore, in one embodiment, the Doppler factor is equal to the ratio of the relative motion speed to the speed of sound in water, and the relative motion speeds corresponding to all Doppler copies are in an arithmetic progression.
[0093] Furthermore, in one embodiment, the interception module 10 is used to perform real-time dual-window sliding correlation detection on the preprocessed received signal and the synchronization signal copy, and determine whether the synchronization signal is detected based on the correlation value of the received signal and the synchronization signal copy in the two sliding windows. When the synchronization signal is detected, the starting position of the synchronization signal is determined as the starting position of the current frame signal.
[0094] Further, in one embodiment, the first processing module 20 is used to perform correlation detection on the first compensation sequence and the training sequence replica in the frequency domain to obtain a first correlation function, and convert the first correlation function from the frequency domain to the time domain to obtain a first correlation peak and its position;
[0095] The second processing module 30 is used to perform correlation detection on the second compensation sequence and the training sequence replica in the frequency domain to obtain a second correlation function, and convert the second correlation function from the frequency domain to the time domain to obtain a second correlation peak and its position.
[0096] Furthermore, in one embodiment, the first compensation sequence, the second compensation sequence and the training sequence copy are converted from the time domain to the frequency domain by fast Fourier transform, and the first correlation function and the second correlation function are converted from the frequency domain to the time domain by fast inverse Fourier transform.
[0097] Furthermore, in one embodiment, the interception module 10 is used to divide the sequence to be tested into K sub-signal segments, and extract L consecutive sub-signal segments therefrom to form the sub-sequence to be tested, wherein K>L>1.
[0098] Among them, the functional implementation of each module in the above-mentioned underwater acoustic communication signal detection device corresponds to the various steps in the above-mentioned underwater acoustic communication signal detection method embodiment, and its functions and implementation processes will not be repeated here one by one.
[0099] In a third aspect, an embodiment of the present application provides an underwater acoustic communication signal detection device, which may be a personal computer (PC), a laptop computer, a server, or other device with data processing capabilities.
[0100] Figure 5 A schematic diagram of the hardware structure of the underwater acoustic communication signal detection device involved in the embodiment of the present application is shown.
[0101] Reference Figure 5 In an embodiment of the present application, the underwater acoustic communication signal detection device may include a processor, a memory, a communication interface, and a communication bus.
[0102] The communication bus may be of any type and is used to interconnect the processor, the memory, and the communication interface.
[0103] The communication interface includes input / output (I / O) interface, physical interface and logical interface, etc., which are used to realize the interconnection of devices inside the underwater acoustic communication signal detection device, and the interface used to realize the interconnection between the underwater acoustic communication signal detection device and other devices (such as other computing devices or user devices). The physical interface can be an Ethernet interface, an optical fiber interface, an ATM interface, etc.; the user device can be a display, a keyboard, etc.
[0104] The memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.
[0105] The processor may be a general-purpose processor, and the general-purpose processor may call the underwater acoustic communication signal detection program stored in the memory and execute the underwater acoustic communication signal detection method provided in the embodiment of the present application. For example, the general-purpose processor may be a central processing unit (CPU). The method executed when the underwater acoustic communication signal detection program is called may refer to the various embodiments of the underwater acoustic communication signal detection method of the present application, and will not be repeated here.
[0106] Those skilled in the art will understand that Figure 5 The hardware structure shown in the figure does not constitute a limitation on the present application, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.
[0107] In a fourth aspect, an embodiment of the present application also provides a readable storage medium.
[0108] An underwater acoustic communication signal detection program is stored on the readable storage medium of the present application, wherein when the underwater acoustic communication signal detection program is executed by the processor, the steps of the underwater acoustic communication signal detection method as described above are implemented.
[0109] Among them, the method implemented when the underwater acoustic communication signal detection program is executed can refer to the various embodiments of the underwater acoustic communication signal detection method of the present application, and will not be repeated here.
[0110] It should be noted that the serial numbers of the above-mentioned embodiments of the present application are only for description and do not represent the advantages or disadvantages of the embodiments.
[0111] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. 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 optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit "first", "second" and "third" to different types.
[0112] In the description of the embodiments of the present application, "exemplary", "for example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary", "for example" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "for example" or "for example" is intended to present related concepts in a specific way.
[0113] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; the “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.
[0114] In some processes described in the embodiments of the present application, multiple operations or steps that appear in a specific order are included, but it should be understood that these operations or steps may not be executed in the order in which they appear in the embodiments of the present application or in parallel, and the sequence number of the operation is only used to distinguish the different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed in sequence or in parallel, and these operations or steps may be combined.
[0115] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, disk, CD) as described above, and includes a number of instructions for a terminal device to execute the methods described in each embodiment of the present application.
[0116] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.
Claims
1. A method for detecting underwater acoustic communication signals, characterized in that: The underwater acoustic communication signal detection method comprises: Determine the starting position of the current frame signal according to the detection of the synchronization signal, intercept the sequence to be tested according to the starting position of the current frame signal and the position of the training sequence in the cooperative communication signal, and intercept the subsequence to be tested from the sequence to be tested, wherein when the current frame signal is a cooperative communication signal, the sequence to be tested includes the training sequence; Performing Doppler search on the sequence to be tested according to the copy of the training sequence to obtain a first Doppler factor, performing Doppler compensation on the sequence to be tested according to the first Doppler factor to obtain a first compensation sequence, and performing correlation detection on the first compensation sequence and the copy of the training sequence to obtain a first correlation peak value and its position; Performing Doppler search on the subsequence to be tested according to the copy of the training sequence to obtain a second Doppler factor, performing Doppler compensation on the subsequence to be tested according to the second Doppler factor to obtain a second compensation sequence, and performing correlation detection on the second compensation sequence and the copy of the training sequence to obtain a second correlation peak value and its position; If the absolute value of the difference between the first Doppler factor and the second Doppler factor is less than or equal to the first threshold, the first correlation peak and the second correlation peak are both greater than or equal to the second threshold, and the absolute value of the difference between the position interval of the first correlation peak and the second correlation peak and the starting position interval of the sequence to be tested and the subsequence to be tested is less than or equal to the third threshold, then the current frame signal is determined to be a cooperative communication signal.
2. The underwater acoustic communication signal detection method according to claim 1, characterized in that: The training sequence copy includes a non-Doppler copy and a plurality of Doppler copies, the non-Doppler copy is used for correlation detection with the first compensation sequence and the second compensation sequence, the Doppler copy is used for Doppler search of the sequence to be tested and the subsequence to be tested, and each Doppler copy corresponds to a Doppler factor; The step of performing Doppler search on the sequence to be tested according to the training sequence copy to obtain the first Doppler factor comprises: Perform correlation detection on the sequence to be tested and each Doppler replica respectively, and determine the Doppler factor corresponding to the Doppler replica with the largest correlation peak as the first Doppler factor; The step of performing Doppler search on the subsequence to be tested according to the training sequence copy to obtain a second Doppler factor comprises: The subsequence to be tested is respectively correlated with each Doppler replica, and the Doppler factor corresponding to the Doppler replica with the largest correlation peak is determined as the second Doppler factor.
3. The underwater acoustic communication signal detection method according to claim 2, characterized in that: The Doppler factor is equal to the ratio of the relative motion speed to the speed of sound in water. The relative motion speeds corresponding to all Doppler copies are in an arithmetic progression.
4. The underwater acoustic communication signal detection method according to claim 1, characterized in that: The step of determining the starting position of the current frame signal according to the synchronization signal detection situation comprises: The preprocessed received signal and the synchronization signal copy are subjected to real-time double-window sliding correlation detection, and whether the synchronization signal is detected is determined based on the correlation value between the received signal and the synchronization signal copy in the two sliding windows. When the synchronization signal is detected, the starting position of the synchronization signal is determined as the starting position of the current frame signal.
5. The underwater acoustic communication signal detection method according to claim 1, characterized in that: The step of performing correlation detection on the first compensation sequence and the training sequence copy to obtain a first correlation peak and its position comprises: Performing correlation detection on the first compensation sequence and the training sequence copy in the frequency domain to obtain a first correlation function, and converting the first correlation function from the frequency domain to the time domain to obtain a first correlation peak and its position; The step of performing correlation detection on the second compensation sequence and the training sequence copy to obtain a second correlation peak and its position comprises: The second compensation sequence is correlated with the training sequence copy in the frequency domain to obtain a second correlation function, and the second correlation function is converted from the frequency domain to the time domain to obtain a second correlation peak and its position.
6. The underwater acoustic communication signal detection method according to claim 5, characterized in that: The first compensation sequence, the second compensation sequence and the training sequence replica are converted from the time domain to the frequency domain by fast Fourier transform, and the first correlation function and the second correlation function are converted from the frequency domain to the time domain by fast inverse Fourier transform.
7. The underwater acoustic communication signal detection method according to claim 1, characterized in that: The step of intercepting a subsequence to be tested from the sequence to be tested comprises: The sequence to be tested is divided into K sub-signal segments, and L consecutive sub-signal segments are extracted from the sub-sequence to be tested, wherein K>L>1.
8. An underwater acoustic communication signal detection device, characterized in that: The underwater acoustic communication signal detection device comprises: An interception module, used to determine the starting position of the current frame signal according to the detection of the synchronization signal, intercept the sequence to be tested according to the starting position of the current frame signal and the position of the training sequence in the cooperative communication signal, and intercept the subsequence to be tested from the sequence to be tested, wherein when the current frame signal is a cooperative communication signal, the sequence to be tested includes the training sequence; A first processing module is used to perform Doppler search on the sequence to be tested according to the training sequence copy to obtain a first Doppler factor, perform Doppler compensation on the sequence to be tested according to the first Doppler factor to obtain a first compensation sequence, and perform correlation detection on the first compensation sequence and the training sequence copy to obtain a first correlation peak value and its position; A second processing module is used to perform Doppler search on the subsequence to be tested according to the copy of the training sequence to obtain a second Doppler factor, perform Doppler compensation on the subsequence to be tested according to the second Doppler factor to obtain a second compensation sequence, and perform correlation detection on the second compensation sequence and the copy of the training sequence to obtain a second correlation peak value and its position; A judgment module is used to determine that the current frame signal is a cooperative communication signal if the absolute value of the difference between the first Doppler factor and the second Doppler factor is less than or equal to the first threshold, the first correlation peak value and the second correlation peak value are both greater than or equal to the second threshold, and the absolute value of the difference between the position interval of the first correlation peak value and the second correlation peak value and the starting position interval of the sequence to be tested and the subsequence to be tested is less than or equal to a third threshold.
9. An underwater acoustic communication signal detection device, characterized in that: The underwater acoustic communication signal detection device includes a processor, a memory, and an underwater acoustic communication signal detection program stored in the memory and executable by the processor, wherein when the underwater acoustic communication signal detection program is executed by the processor, the steps of the underwater acoustic communication signal detection method as described in any one of claims 1 to 7 are implemented.
10. A readable storage medium, characterized in that: The readable storage medium stores an underwater acoustic communication signal detection program, wherein when the underwater acoustic communication signal detection program is executed by the processor, the steps of the underwater acoustic communication signal detection method according to any one of claims 1 to 7 are implemented.