Method, device and medium for eliminating periodic pulse interference of underwater acoustic communication signal

Abstract

The present application belongs to the field of underwater acoustic communication signal interference elimination, and discloses a kind of underwater acoustic communication signal periodic pulse interference elimination method, device and medium, comprising: step 1: analyze the cause and characteristics of periodic pulse interference;Step 2: construct the mathematical expression of signal received by hydrophone and periodic pulse interference;Step 3: establish detection statistics according to generalized log-likelihood ratio criterion and minimum description length;Step 4: estimate the period of pulse interference;Step 5: calculate the signal of periodic pulse interference by using least square algorithm;Step 6: eliminate interference on underwater acoustic communication signal.The present application establishes the mathematical model of signal received by hydrophone and periodic pulse interference, which is much better than the traditional frequency domain filtering method.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of underwater acoustic communication signal interference cancellation, in particular to an underwater acoustic communication signal periodic pulse interference cancellation method, device and medium. BACKGROUND

[0002] The influence of periodic pulse interference on underwater acoustic communication is multifaceted, as it not only reduces communication quality, but also can lead to complete failure of the communication system. The specific influences are as follows:

[0003] 1) Signal quality is reduced: Periodic pulse interference can introduce additional noise components into the underwater acoustic signal, which reduces the signal-to-noise ratio. Since underwater acoustic communication systems rely on the receiving end being able to accurately detect and decode the signal, a reduction in signal-to-noise ratio directly affects the reliability of data transmission. In the case of a low signal-to-noise ratio, the receiving end is difficult to demodulate correctly, resulting in data errors and loss.

[0004] 2) Communication distance is limited: The presence of periodic pulse interference can limit the effective distance of underwater acoustic communication. Since interference accumulates with distance, long-distance communication is more susceptible to interference. In long-distance communication, even weak periodic pulse interference can cause the communication link to fail.

[0005] Therefore, it is necessary to eliminate the periodic pulse interference caused by external power supply problems. The present application analyzes the generation and characteristics of periodic pulse interference, and uses the mathematical relationship between the signals received by the hydrophone and the periodic pulse interference to eliminate the influence of periodic pulse interference on underwater acoustic communication signals, thereby improving the reliability of underwater acoustic communication signals. SUMMARY

[0006] The present application aims to provide an underwater acoustic communication signal periodic pulse interference cancellation method, device and medium to solve the problems raised in the background art.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0008] An underwater acoustic communication signal periodic pulse interference cancellation method, comprising:

[0009] Step 1: Analyze the causes and characteristics of periodic pulse interference;

[0010] Step 2: Construct the mathematical expression of the signal received by the hydrophone and the periodic pulse interference;

[0011] Step 3: Establish a detection statistic according to the generalized log-likelihood ratio criterion and the minimum description length;

[0012] Step 4: Estimate the period of the pulse interference;

[0013] Step 5: Calculate the signal of periodic pulse interference by using least square algorithm;

[0014] Step 6: Eliminate the interference of the underwater acoustic communication signal.

[0015] Further, the step 2 comprises:

[0016] Step 2.1: Obtain a signal received by a hydrophone, the signal comprising environmental noise and underwater acoustic communication signal, and superimposed with periodic pulse interference;

[0017] Step 2.2: Under the action of high-energy periodic pulse interference, the underwater acoustic communication signal is combined with the environmental noise, and the combined variable obeys zero-mean Gaussian distribution with variance σ 2 ;

[0018] Step 2.3: According to the characteristics of the periodic pulse interference, the received signal is further expressed by using a periodic pulse interference.

[0019] Further, the step 3 is specifically to obtain the detection statistic of the base frequency of the periodic signal according to the generalized log-likelihood ratio criterion and the minimum description length.

[0020] Further, the step 4 is specifically to traverse the frequency, and find the frequency at which the detection statistic is maximum as the estimation value of the base frequency of the periodic signal, and at this time, the estimation value of the period is the reciprocal of the base frequency.

[0021] Further, the step 5 comprises:

[0022] Step 5.1: According to the mathematical expression of the signal received by the hydrophone in multiple periods and the pulse interference in one period, construct an optimization problem;

[0023] Step 5.2: Solve the optimization problem to obtain the least square estimation of the pulse interference in one period;

[0024] Step 5.3: Combine the structure of the matrix in the least square estimation to simplify the estimation value.

[0025] Further, the step 6 comprises:

[0026] Step 6.1: Divide the signal received by the hydrophone according to the estimation value of the period of the periodic pulse interference;

[0027] Step 6.2: Subtract the estimation value of the periodic pulse interference from each part of the divided part to eliminate the periodic pulse interference of the underwater acoustic communication signal.

[0028] The application provides a water acoustic communication signal periodic pulse interference elimination device, comprising one or more processors, which are used for realizing a water acoustic communication signal periodic pulse interference elimination method as described above.

[0029] The application provides a readable storage medium, which stores a program, and the program is executed by a processor to realize a water acoustic communication signal periodic pulse interference elimination method as described above.

[0030] Compared with the prior art, the application has the beneficial effects that:

[0031] 1) The water acoustic communication signal periodic pulse interference elimination method provided by the application proposes the generation and characteristics of periodic pulse interference, and can provide a reference for elimination of common periodic interference such as propeller noise and sonar pulse in subsequent water acoustic communication.

[0032] 2) The water acoustic communication signal periodic pulse interference elimination method provided by the application establishes a mathematical model of the signal received by a hydrophone and periodic pulse interference, which is much better than a traditional frequency domain filtering method.

[0033] 3) The water acoustic communication signal periodic pulse interference elimination method provided by the application uses a least square algorithm to calculate the signal of periodic pulse interference, and optimizes the algorithm complexity by using the characteristics of the matrix in the formula, so that the periodic pulse interference is accurately estimated while the complexity of the algorithm is reduced.

[0034] 4) The water acoustic communication signal periodic pulse interference elimination method provided by the application can effectively eliminate the influence of periodic pulse interference on water acoustic communication signals and improve the reliability of water acoustic communication signals. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a flowchart of the water acoustic communication signal periodic pulse interference elimination method provided by the application.

[0036] Figure 2 It is a signal received by a hydrophone when a user external power supply is enabled and when the user external power supply is disabled.

[0037] Figure 3 It is periodic pulse interference.

[0038] Figure 4 It is a segment of the signal received by the hydrophone.

[0039] Figure 5 It is a detection statistic based on a generalized log-likelihood ratio criterion and a minimum description length calculation.

[0040] Figure 6 It is an estimation result of the periodic pulse interference based on a least square algorithm.

[0041] Figure 7 is the result before and after the elimination of periodic pulse interference of underwater acoustic communication signal.

[0042] Figure 8 is the comparison diagram of demodulation constellation before and after the elimination of periodic pulse interference of underwater acoustic communication signal, (a) is the demodulation constellation before the elimination of periodic pulse interference, (b) is the demodulation constellation after the elimination of periodic pulse interference.

[0043] Figure 9 is the structural schematic diagram of the device for eliminating periodic pulse interference of underwater acoustic communication signal. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0045] The method for eliminating periodic pulse interference of underwater acoustic communication signal comprises the following steps: Figure 1 as shown in the figure, comprising:

[0046] Step 1: analyze the causes and characteristics of periodic pulse interference. Specifically, it comprises:

[0047] Step 1.2: analyze the causes of periodic pulse interference. In the process of underwater acoustic communication, the hydrophone refers to the transducer for converting acoustic signals into electric signals, used to receive acoustic signals in water. The hydrophone needs external power supply equipment for work, the external power supply equipment is an outdoor power supply, which is a kind of energy storage device that can output alternating current and direct current. The working mechanism of the outdoor power supply output alternating current is that the direct current passes through the inverter, and is inverted into alternating current, while retaining the direct current output. The process of inverting will produce harmonic interference, when these interferences interact with the hydrophone, the additive periodic pulse interference will be introduced into the received underwater acoustic communication signal, and then affect the reception of underwater acoustic communication signal by the hydrophone, as shown in the figure, Figure 2 When the user outdoor power supply is used, the signal received by the hydrophone can obviously show that there is periodic pulse interference.

[0048] Step 1.2: The characteristics of periodic impulsive interference are frequency stability, persistence and predictability. Frequency stability is reflected in the relative stability of the frequency, which is usually fixed at 50Hz or 60Hz, and is periodic at this frequency; persistence is reflected in the fact that periodic impulsive interference is persistent, i.e. during the operation of the hydrophone powered by an outdoor power supply, the influence of periodic impulsive interference needs to be considered; predictability is reflected in the fact that periodic impulsive interference is predictable to some extent due to the relative stability of the frequency and characteristics of periodic impulsive interference, which helps to develop effective interference cancellation techniques, such as Figure 3 As shown in FIG. 1, in this embodiment, the periodic impulsive interference exhibits frequency stability, persistence and predictability, with a period of about 0.02s and a frequency of about 50Hz.

[0049] Step 2: Constructing mathematical expressions for the signal received by the hydrophone and the periodic impulsive interference. Specifically, it includes:

[0050] Step 2.1: Obtain a segment of the signal received by the hydrophone y r As shown in FIG. 2, in this embodiment, the sampling rate is f s = 96kHz, the signal length N = 2f s , the signal includes environmental noise n and underwater acoustic communication signal s, and is superimposed with fundamental frequency f0, unknown periodic impulsive interference with period L Figure 4 The received signal can be expressed as:

[0051] .

[0052] Step 2.2: Under the influence of high-energy periodic impulsive interference, the underwater acoustic communication signal s can be combined with the environmental noise n, defined as w = s + n, so the received signal can be rewritten as:

[0053] ,

[0054] where w follows a zero-mean Gaussian distribution with variance σ 2 .

[0055] Step 2.3: According to the characteristics of periodic impulsive interference, the received signal can be further expressed using a periodic impulsive interference. That is, if the period of periodic impulsive interference is L, then a periodic impulsive interference is x, so let y i be the first L sampling points of the signal y r received by the hydrophone, i.e. the first period of y r , so the mathematical expression of y i and a periodic impulsive interference x is:

[0056] , ​

[0057] where w i The first L samples of w 2 are also subject to a zero-mean Gaussian distribution with variance σ r The first N’ samples of y are denoted as y, where N’ = ML, s M = 50, and y = y r Thus, the mathematical relationship between the received signal y and the periodic pulse interference x in one period can be further expressed as:

[0058] ,

[0059] where A is composed of M unit matrices I, and has:

[0060] ,

[0061] where the superscript T denotes the transpose.

[0062] Step 3: Establish the detection statistic according to the generalized log-likelihood ratio criterion and the minimum description length. Specifically, according to the generalized log-likelihood ratio criterion and the minimum description length, the detection statistic of the fundamental frequency f0 of the periodic signal is obtained as:

[0063] ,

[0064] where y r [n] is the nth element of y r , K is an intermediate number, max denotes the maximum value, and exp denotes the exponential function. In this embodiment, as shown in Figure 5 , the detection statistic under different p values is obtained.

[0065] Step 4: Estimate the period of the pulse interference. Specifically, traverse p to obtain the estimated value

[0066] ,

[0067] where arg max is an operator that finds the parameter (or parameter set) that makes the function maximum.

[0068] As shown in Figure 5 , when p = 0.5, the estimated value of the fundamental frequency f0 of the periodic pulse interference is , and the estimated value of the period is . ​​​

[0069] Step 5: Calculate the signal of periodic pulse interference by using least square algorithm. Specifically, it includes:

[0070] Step 5.1: According to the mathematical expression of the signal y received by the hydrophone in M periods and the pulse interference x in one period, construct the optimization problem as:

[0071] ,

[0072] Min represents taking the minimum value.

[0073] Step 5.2: Solve the optimization problem to obtain the least square estimation of the periodic pulse interference x :

[0074] .

[0075] Step 5.3: Combine the structure of A in the least square estimation, A T A can be simplified as A T A=MI.

[0076] According to the simplified result, the least square estimation of the periodic pulse interference x can be simplified as:

[0077] .

[0078] In this embodiment, the estimation result of the periodic pulse interference is as shown in Figure 6 .

[0079] Step 6: Perform interference cancellation on the underwater acoustic communication signal. Specifically, it includes:

[0080] Step 6.1: Divide the signal y received by the hydrophone according to the period of the periodic pulse interference. .

[0081] Step 6.2: Subtract the estimation of the periodic pulse interference from each part to realize the cancellation of the periodic pulse interference of the underwater acoustic communication signal, as shown in Figure 7 , which is the result before and after the cancellation of the periodic pulse interference of the underwater acoustic communication signal.

[0082] In this embodiment, the underwater acoustic communication signal is demodulated before and after the cancellation of the periodic pulse interference, and the demodulation constellation diagram and the bit error rate are as shown in Figure 8 . By using the method for canceling the periodic pulse interference of the underwater acoustic communication signal proposed in the present application, the bit error rate is reduced by 17.23%.

[0083] The water acoustic communication signal periodic pulse interference elimination method can eliminate the influence of periodic pulse interference on the water acoustic communication signal and improve the reliability of water acoustic communication signal communication.

[0084] Referring to Figure 9 The water acoustic communication signal periodic pulse interference elimination device provided by the embodiment of the present application comprises one or more processors, which are used to implement the water acoustic communication signal periodic pulse interference elimination method in the above embodiment.

[0085] The device embodiment of the water acoustic communication signal periodic pulse interference elimination device can be applied to any device with data processing capability, which can be a device such as a computer or the like. The device embodiment can be implemented by software, or by hardware or a combination of software and hardware. Taking the software implementation as an example, as a device in a logical sense, it is formed by reading the corresponding computer program instructions in the non-volatile memory into the memory and running by the processor of the device with data processing capability. Figure 9 As shown in the figure, it is a hardware structure diagram of the device with data processing capability where the water acoustic communication signal periodic pulse interference elimination device is located, in addition to the processor, the memory, the network interface, and the non-volatile memory shown in the figure, the device with data processing capability where the device is located usually includes other hardware according to the actual function of the device with data processing capability, and details are not described here. Figure 9 As shown in the figure, it is a hardware structure diagram of the device with data processing capability where the water acoustic communication signal periodic pulse interference elimination device is located, in addition to the processor, the memory, the network interface, and the non-volatile memory shown in the figure, the device with data processing capability where the device is located usually includes other hardware according to the actual function of the device with data processing capability, and details are not described here.

[0086] The implementation process of the functions and roles of each unit in the above device is specifically described in the implementation process of the corresponding steps in the above method, and details are not described here.

[0087] The technical features of the above embodiments can be combined arbitrarily, and to make the description concise, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0088] The embodiment of the present application further provides a readable storage medium, which stores a program, and the program is executed by a processor to implement the water acoustic communication signal periodic pulse interference elimination method in the above embodiment.

[0089] The readable storage medium can be an internal storage unit of any of the aforementioned data processing capable devices, such as a hard disk or a memory. The readable storage medium can also be an external storage device, such as a plug-in hard disk, a Smart Media Card (SMC), an SD card, a Flash Card, etc. Further, the readable storage medium can include both an internal storage unit of any of the aforementioned data processing capable devices and an external storage device. The readable storage medium is used to store the computer program and other programs and data required by the aforementioned data processing capable devices, and can also be used to temporarily store data that has been output or will be output.

[0090] While the embodiments of the present application have been illustrated and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and alterations can be made therein without departing from the spirit and scope of the application, which are defined by the following claims and their equivalents.

Claims

1. A method for removing periodic pulse interference from an underwater acoustic communication signal, the method comprising: The method comprises the following steps: Step 1: analyzing the causes and characteristics of the periodic pulse interference; Step 2: constructing a mathematical expression of the hydrophone-received signal and the periodic pulse interference, comprising: Step 2.1: obtaining a hydrophone-received signal, which comprises environmental noise and underwater acoustic communication signals and is superimposed with periodic pulse interference; Step 2.2: Under the action of high-energy periodic pulse interference, the underwater acoustic communication signal s is combined with the environmental noise n, defined as w = s + n, and the combined variable w obeys the zero-mean Gaussian distribution with variance σ 2 ​ Step 2.3: according to the characteristics of the periodic pulse interference, the received signal is further expressed by using a periodic pulse interference; the mathematical relationship between the hydrophone-received signal y and the periodic pulse interference x is further expressed as: ， wherein A is composed of M unit matrices I, and has: ， wherein the superscript T represents transposition; Step 3: establishing a detection statistic according to the generalized log-likelihood ratio criterion and the minimum description length; Step 4: estimating the period of the pulse interference; Step 5: calculating the signal of the periodic pulse interference by using a least square algorithm; Step 6: removing the interference from the underwater acoustic communication signal.

2. The method according to claim 1, wherein, The step 3 specifically comprises obtaining a detection statistic of the base frequency of the periodic signal according to the generalized log-likelihood ratio criterion and the minimum description length.

3. The method of claim 1, wherein, The step 4 specifically comprises traversing the frequency to find a frequency at which the detection statistic is maximum, and taking the frequency as an estimated value of the base frequency of the periodic signal, and at this time, the estimated value of the period is the reciprocal of the base frequency.

4. The method of claim 1, wherein, The step 5 comprises: Step 5.1: constructing an optimization problem according to the mathematical expression of the hydrophone-received signal and the periodic pulse interference in multiple periods; Step 5.2: solving the optimization problem to obtain a least square estimation of the periodic pulse interference; Step 5.3: combining the structure of the matrix in the least square estimation to simplify the estimated value.

5. The method of claim 1, wherein, The step 6 comprises: Step 6.1: dividing the hydrophone-received signal according to the estimated value of the period of the periodic pulse interference; Step 6.2: subtracting the estimated value of the periodic pulse interference from each part to remove the periodic pulse interference from the underwater acoustic communication signal.

6. A device for eliminating periodic pulse interference of a water acoustic communication signal, characterized in that The device comprises one or more processors for implementing the method for removing periodic pulse interference from an underwater acoustic communication signal according to any one of claims 1-5.

7. A readable storage medium, characterized by, The device has a program stored thereon, and the program is executed by the processor to implement the method for removing periodic pulse interference from an underwater acoustic communication signal according to any one of claims 1-5.

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