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

Abstract

The invention belongs to the field of underwater acoustic communication signal interference elimination, and discloses an underwater acoustic communication signal periodic pulse interference elimination method and device and a medium, and the method comprises the steps: 1, analyzing the generation reasons and characteristics of periodic pulse interference; 2, constructing a mathematical expression of signals received by the hydrophone and periodic pulse interference; step 3, establishing detection statistics according to a generalized log-likelihood ratio criterion and the minimum description length; step 4, estimating a pulse interference period; step 5, calculating by using a least square algorithm to obtain a periodic pulse interference signal; and 6, performing interference elimination on the underwater acoustic communication signal. According to the method for eliminating the periodic pulse interference of the underwater acoustic communication signals, a mathematical model of the signals received by the hydrophone and the periodic pulse interference is established, and the method is greatly superior to a traditional frequency domain filtering method.

Description

Technical Field

[0001] The present invention relates to the field of underwater acoustic communication signal interference elimination, and in particular to a method, device and medium for eliminating periodic pulse interference of underwater acoustic communication signals. Background Art

[0002] Periodic pulse interference has many impacts on underwater acoustic communication. It not only reduces the communication quality but may also cause the complete failure of the communication system. The specific impacts are:

[0003] 1) Degraded signal quality: Periodic pulse interference introduces additional noise into underwater acoustic signals, reducing the signal-to-noise ratio (SNR). Because underwater acoustic communication systems rely on the receiver's ability to accurately detect and decode signals, a reduced SNR directly impacts data transmission reliability. With a low SNR, the receiver struggles to correctly demodulate, leading to data errors and loss.

[0004] 2) Limited communication range: The presence of periodic pulse interference can limit the effective range of underwater acoustic communications. Because interference accumulates with distance, long-distance communications are more susceptible to interference. Even weak periodic pulse interference can cause the communication link to fail over long distances.

[0005] Therefore, it is necessary to eliminate the periodic pulse interference caused by external power supply problems. This invention analyzes the generation and characteristics of periodic pulse interference and uses the mathematical relationship between the signal received by the hydrophone and the periodic pulse interference to eliminate the impact of periodic pulse interference on underwater acoustic communication signals, thereby improving the communication reliability of underwater acoustic communication signals. Summary of the Invention

[0006] The purpose of the present invention is to provide a method, device and medium for eliminating periodic pulse interference of underwater acoustic communication signals to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for eliminating periodic pulse interference of underwater acoustic communication signals, comprising:

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

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

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

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

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

[0014] Step 6: Eliminate interference from underwater acoustic communication signals.

[0015] Furthermore, the step 2 includes:

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

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

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

[0019] Furthermore, the step 3 specifically obtains the detection statistic of the fundamental frequency of the periodic signal according to the generalized log-likelihood ratio criterion and the minimum description length.

[0020] Furthermore, the step 4 is specifically to traverse the frequencies and find the frequency when the detection statistic is maximized as the estimated value of the fundamental frequency of the periodic signal. At this time, the estimated value of the period is the reciprocal of the fundamental frequency.

[0021] Furthermore, the step 5 includes:

[0022] Step 5.1: Construct an optimization problem based on the mathematical expression of the interference between the signal received by the hydrophone and the pulse of one cycle over multiple cycles;

[0023] Step 5.2: Solve the optimization problem to obtain the least squares estimate of the pulse interference for one cycle;

[0024] Step 5.3: Simplify the estimated value based on the structure of the matrix in the least squares estimation.

[0025] Furthermore, the step 6 includes:

[0026] Step 6.1: Segment the signal received by the hydrophone according to the estimated period of the periodic pulse interference;

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

[0028] The present invention provides a device for eliminating periodic pulse interference of underwater acoustic communication signals, comprising one or more processors for implementing the method for eliminating periodic pulse interference of underwater acoustic communication signals as described above.

[0029] The present invention provides a readable storage medium having a program stored thereon. When the program is executed by a processor, the method for eliminating periodic pulse interference of underwater acoustic communication signals as described above is implemented.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1) The method for eliminating periodic pulse interference in underwater acoustic communication signals of the present invention proposes the generation and characteristics of periodic pulse interference, which can provide a reference for eliminating periodic interference such as propeller noise and sonar pulses that are common in underwater acoustic communications in the future.

[0032] 2) The method for eliminating periodic pulse interference of underwater acoustic communication signals of the present invention establishes a mathematical model of the signal received by the hydrophone and the periodic pulse interference, which is significantly better than the traditional frequency domain filtering method.

[0033] 3) The method for eliminating periodic pulse interference in underwater acoustic communication signals of the present invention uses a least squares algorithm to calculate the signal of periodic pulse interference and optimizes the algorithm complexity by utilizing the characteristics of the matrix in the formula, thereby accurately estimating the periodic pulse interference while reducing the algorithm complexity.

[0034] 4) The method for eliminating periodic pulse interference of underwater acoustic communication signals of the present invention can effectively eliminate the influence of periodic pulse interference on underwater acoustic communication signals and improve the communication reliability of underwater acoustic communication signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a flow chart of a method for eliminating periodic pulse interference of underwater acoustic communication signals.

[0036] Figure 2 It is the signal received by the hydrophone when using outdoor power and when not using outdoor power.

[0037] Figure 3 It is a periodic pulse interference.

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

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

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

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

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

[0043] Figure 9 The figure is a schematic structural diagram of a device for eliminating periodic pulse interference of underwater acoustic communication signals according to the present invention. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] The present invention provides a method for eliminating periodic pulse interference of underwater acoustic communication signals, such as Figure 1 Shown, including:

[0046] Step 1: Analyze the causes and characteristics of periodic pulse interference. Specifically include:

[0047] Step 1.2: Analyze the cause of periodic pulse interference. In the process of underwater acoustic communication, a hydrophone refers to a transducer that converts acoustic signals into electrical signals, which is used to receive acoustic signals in water. The operation of the hydrophone requires an external power supply device, which is an outdoor power supply. The outdoor power supply is an energy storage device that can output AC and DC. The working mechanism of the outdoor power supply outputting AC power is that DC power passes through an inverter and is inverted into AC power while retaining the DC output. The inversion process will generate harmonic interference. When these interferences interact with the hydrophone, additive periodic pulse interference will be introduced into the received underwater acoustic communication signal, thereby affecting the hydrophone's reception of the underwater acoustic communication signal, such as Figure 2 As shown in the figure, the signals received by the hydrophone when using the outdoor power supply and when not using the outdoor power supply, it can be clearly seen that there is periodic pulse interference when using the outdoor power supply.

[0048] Step 1.2: The characteristics of periodic pulse interference are frequency stability, persistence, and predictability. Frequency stability means that the frequency is relatively stable, usually fixed at 50Hz or 60Hz, and the period is based on this frequency. Persistence means that the periodic pulse interference is persistent, that is, the impact of periodic pulse interference needs to be considered during the operation of the hydrophone powered by outdoor power. Predictability means that the frequency and characteristics of periodic pulse interference are relatively stable, and periodic pulse interference is predictable to a certain extent, which helps to develop effective interference elimination technology, such as Figure 3 As shown, in this embodiment, the periodic pulse interference exhibits frequency stability, persistence and predictability, with a period of approximately 0.02s and a frequency of approximately 50Hz.

[0049] Step 2: Construct a mathematical expression for the signal received by the hydrophone and the periodic pulse interference. Specifically, it includes:

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

[0051] .

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

[0053] ,

[0054] Among them, w obeys zero mean and variance is σ 2 Gaussian distribution.

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

[0056] ,

[0057] Among them, w i The first L sampling points corresponding to w also obey zero mean and variance σ 2 Gaussian distribution. Take y r The first N' sampling points of compose y, where N'=ML, , M is the number of periodic signals within N' sampling points. In this embodiment, N'=N=2f s , M=50, y=y r Therefore, in M ​​cycles, the mathematical relationship between the signal y received by the hydrophone and the pulse interference x of one cycle can be further expressed as:

[0058] ,

[0059] Among them, A is composed of M unit matrices I, with:

[0060] ,

[0061] The superscript T indicates transposition.

[0062] Step 3: Establish the detection statistic based on 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. for:

[0063] ,

[0064] Among them, y r [n] is y r The nth element of , K is the middle number, , max represents the maximum value, and exp represents the exponential function. In this embodiment, Figure 5 Shown are the test statistics at different p values.

[0065] Step 4: Estimate the period of the pulse interference. Specifically, traverse , and get an estimate of p for:

[0066] ,

[0067] Where arg max is an operator that finds the argument (or set of arguments) that maximizes the function.

[0068] like Figure 5 As shown, , at this time, the estimated value of the periodic pulse interference fundamental frequency f0 is , the estimated value of the period is .

[0069] Step 5: Use the least squares algorithm to calculate the signal of periodic pulse interference. Specifically include:

[0070] Step 5.1: Based on the mathematical expression of the signal y received by the hydrophone and the pulse interference x of one cycle in M ​​cycles, the optimization problem is constructed as:

[0071] ,

[0072] Min means taking the minimum value.

[0073] Step 5.2: Solve the optimization problem and obtain the least squares estimate of the periodic pulse interference x for:

[0074] .

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

[0076] According to the simplified result, the least squares estimate of the periodic pulse interference x is Can be simplified to:

[0077] .

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

[0079] Step 6: Eliminate interference from underwater acoustic communication signals. Specifically include:

[0080] Step 6.1: The signal received by the hydrophone is converted to the period of the periodic pulse interference. Perform the split.

[0081] Step 6.2: Subtract the estimation of periodic pulse interference from each segmented part to eliminate the periodic pulse interference of the underwater acoustic communication signal, such as Figure 7 As shown, the results before and after the elimination of periodic pulse interference of underwater acoustic communication signals.

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

[0083] The method for eliminating periodic pulse interference of underwater acoustic communication signals proposed in the present invention can eliminate the influence of periodic pulse interference on underwater acoustic communication signals and improve the communication reliability of underwater acoustic communication signals.

[0084] See also Figure 9 An embodiment of the present invention provides a device for eliminating periodic pulse interference of underwater acoustic communication signals, which includes one or more processors for implementing a method for eliminating periodic pulse interference of underwater acoustic communication signals in the above embodiment.

[0085] An embodiment of a device for eliminating periodic pulse interference of underwater acoustic communication signals according to the present invention can be applied to any device with data processing capability, and the device with data processing capability can be a device or apparatus such as a computer. The device embodiment can be implemented through software, or through hardware or a combination of software and hardware. Taking software implementation as an example, as a device in a logical sense, it is formed by the processor of any device with data processing capability in which it is located reading the corresponding computer program instructions in the non-volatile memory into the memory for execution. From the hardware level, if Figure 9 As shown in the figure, it is a hardware structure diagram of any device with data processing capability where the device for eliminating periodic pulse interference of underwater acoustic communication signals of the present invention is located. Figure 9 In addition to the processor, memory, network interface, and non-volatile memory shown, any device with data processing capabilities in the embodiment may also include other hardware according to the actual function of the device with data processing capabilities, which will not be described in detail.

[0086] The implementation process of the functions and effects of each unit in the above-mentioned device is specifically described in the implementation process of the corresponding steps in the above-mentioned method, and will not be repeated here.

[0087] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] An embodiment of the present invention further provides a readable storage medium having a program stored thereon. When the program is executed by a processor, a method for eliminating periodic pulse interference of underwater acoustic communication signals in the above embodiment is implemented.

[0089] The readable storage medium may be an internal storage unit of any device with data processing capabilities described in any of the aforementioned embodiments, such as a hard disk or memory. The readable storage medium may 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. equipped on the device. Furthermore, the readable storage medium may also include both an internal storage unit and an external storage device of any device with data processing capabilities. The readable storage medium is used to store the computer program and other programs and data required by any device with data processing capabilities, and may also be used to temporarily store data that has been output or is to be output.

[0090] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for eliminating periodic pulse interference of underwater acoustic communication signals, characterized in that: include: Step 1: Analyze the causes and characteristics of periodic pulse interference; Step 2: Construct a mathematical expression for the signal received by the hydrophone and the periodic pulse interference; Step 3: Establish the detection statistic based on the generalized log-likelihood ratio criterion and minimum description length; Step 4: Estimate the period of the pulse interference; Step 5: Calculate the signal of periodic pulse interference using the least squares algorithm; Step 6: Eliminate interference from underwater acoustic communication signals.

2. A method for eliminating periodic pulse interference of underwater acoustic communication signals according to claim 1, characterized in that: The step 2 includes: Step 2.1: Obtain a signal received by a hydrophone, which includes environmental noise and underwater acoustic communication signals, and is superimposed with periodic pulse interference; Step 2.2: Under the influence of high-energy periodic pulse interference, the underwater acoustic communication signal is merged with the environmental noise. The merged variable has zero mean and variance σ 2 Gaussian distribution; Step 2.3: According to the characteristics of periodic pulse interference, the received signal is further expressed using a periodic pulse interference.

3. The method for eliminating periodic pulse interference of underwater acoustic communication signals according to claim 1, characterized in that: The step 3 specifically involves obtaining the detection statistic of the fundamental frequency of the periodic signal according to the generalized log-likelihood ratio criterion and the minimum description length.

4. The method for eliminating periodic pulse interference of underwater acoustic communication signals according to claim 1, characterized in that: The step 4 is specifically to traverse the frequencies and find the frequency that maximizes the detection statistic as the estimated value of the fundamental frequency of the periodic signal. At this time, the estimated value of the period is the reciprocal of the fundamental frequency.

5. The method for eliminating periodic pulse interference of underwater acoustic communication signals according to claim 1, characterized in that: The step 5 comprises: Step 5.1: Construct an optimization problem based on the mathematical expression of the interference between the signal received by the hydrophone and the pulse of one cycle over multiple cycles; Step 5.2: Solve the optimization problem to obtain the least squares estimate of the pulse interference for one cycle; Step 5.3: Simplify the estimated value based on the structure of the matrix in the least squares estimation.

6. The method for eliminating periodic pulse interference of underwater acoustic communication signals according to claim 1, characterized in that: The step 6 comprises: Step 6.1: Segment the signal received by the hydrophone according to the estimated period of the periodic pulse interference; Step 6.2: Subtract the estimated value of the periodic pulse interference from each segmented part to eliminate the periodic pulse interference of the underwater acoustic communication signal.

7. A device for eliminating periodic pulse interference of underwater acoustic communication signals, characterized in that: It comprises one or more processors for implementing a method for eliminating periodic pulse interference of underwater acoustic communication signals according to any one of claims 1 to 6.

8. A readable storage medium, characterized in that: A program is stored thereon, and when the program is executed by a processor, a method for eliminating periodic pulse interference of underwater acoustic communication signals as described in any one of claims 1 to 6 is implemented.

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