A high-resolution high real-time acoustic target direction of arrival estimation method

Abstract

The present application relates to acoustic target direction of arrival estimation method, specifically relates to a kind of high resolution high real-time acoustic target direction of arrival estimation method, the technical problem of poor real-time of the acoustic target DOA estimation method of existing using MUSIC algorithm is solved.The search state of the present application is divided into no target, discovers suspected target and stable tracking target, for different search state, set different spatial spectrum search range and spatial resolution, can avoid data redundancy, improve the real-time of acoustic target DOA estimation;At the same time, by adjusting the spatial spectrum search range and spatial resolution of different search state, the spatial spectrum search range is greatly reduced in stable tracking target search state, and spatial resolution is greatly improved, the accuracy of acoustic target DOA estimation can be improved.

Description

Technical Field

[0001] This invention relates to a method for estimating the direction of arrival (DOA) of an acoustic target, specifically a high-resolution, high-real-time method for estimating the DOA of an acoustic target. Background Technology

[0002] Direction of Arrival (DOA) estimation for acoustic targets is based on acoustic methods. Its core task is to determine the spatial orientation of the acoustic target by processing the target's radiated sound waves received by a sensor array. Acoustic target DOA estimation technology demonstrates irreplaceable application value in numerous fields due to its unique advantages of being non-contact, long-distance, and capable of all-weather operation. For example, in equipment fault location, acoustic target DOA estimation technology can accurately locate the fault point by identifying the acoustic signals of partial discharge in transformers; in target detection, it improves the accuracy of target detection by analyzing the propagation characteristics of sound waves; and it also has significant applications in underwater detection and other fields.

[0003] Multiple Signal Classification (MUSIC) is a commonly used algorithm for acoustic target DOA estimation. This algorithm utilizes the orthogonality between the signal subspace and the noise subspace to construct a spatial spectral function. By searching the spatial spectrum of the spectral peaks, it obtains the acoustic target DOA estimation result. It has advantages such as ultra-high estimation accuracy, strong signal resolution, good noise robustness, high adaptability, and multi-target estimation capability.

[0004] However, the estimation accuracy of the MUSIC algorithm is highly dependent on the spatial resolution set during the spatial spectrum search process. A higher spatial resolution results in a smaller sampling interval for the spatial spectrum peaks, leading to higher accuracy in acoustic target DOA estimation. Therefore, this advantage is accompanied by a significant performance drawback: poor real-time performance in acoustic target DOA estimation. In real-world sound environments, target-radiated sound waves often exhibit broadband characteristics, requiring subspace decomposition and spatial spectrum search at multiple sound wave frequencies. As the spatial resolution increases, the computational load of the spatial spectrum search at each sound wave frequency increases exponentially, significantly increasing the overall computation time of the MUSIC algorithm. This problem is further amplified in scenarios with high real-time requirements, such as dynamic acoustic target tracking and real-time sound field monitoring, making it difficult to meet the stringent response speed requirements of engineering applications. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problem of poor real-time performance of existing acoustic target DOA estimation methods using the MUSIC algorithm, and to provide a high-resolution, high-real-time acoustic target DOA estimation method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A high-resolution, high-real-time acoustic target direction-of-arrival estimation method, characterized by the following steps:

[0008] Step 1: Set the initial parameters for DOA estimation, then divide the search states of DOA estimation into no target, suspected target found, and stable target tracking, and set the spatial spectrum search range and spatial resolution for different search states; the DOA estimation adopts the MUSIC algorithm, and the initial parameters include the maximum change angle, spatial spectrum background noise, and signal power threshold;

[0009] Step 2: Set the search state to targetless, acquire the real-time search signal, and perform spatial spectrum search and DOA estimation based on the real-time search signal according to the spatial spectrum search range and spatial resolution of the targetless search state, to obtain the acoustic target spatial spectrum and acoustic target direction of arrival and output the acoustic target direction of arrival.

[0010] Step 3: Calculate the signal power of the real-time search signal, and calculate the peak intensity of the spatial spectrum of the real-time search signal based on the acoustic target spatial spectrum.

[0011] Step 4: Repeat steps 2-3. If the peak intensity of the spatial spectrum of the real-time search signal acquired in n1 consecutive times is greater than the spatial spectrum noise floor and the signal power is greater than the signal power threshold, then proceed to step 5; where n1 is an integer greater than 1.

[0012] Step 5: Update the search status to "suspected target found", continue to acquire real-time search signals, and perform spatial spectrum search and DOA estimation based on the real-time search signals according to the spatial spectrum search range and spatial resolution of the suspected target found search status, to obtain and output the acoustic target wave direction of arrival.

[0013] Step 6: Repeat step 5. If the change between the acoustic target direction of arrival obtained from two consecutive DOA estimates is less than or equal to the maximum change angle, then proceed to step 7; where n2 is an integer greater than 1.

[0014] Step 7: Update the search status to a stable tracking target, continue to acquire real-time search signals, and perform spatial spectrum search and DOA estimation based on the real-time search signals according to the spatial spectrum search range and spatial resolution of the stable tracking target search status, to obtain and output the acoustic target direction of arrival.

[0015] Step 8: Repeat step 7. If the change between two consecutive DOA estimates of the acoustic target is greater than the maximum change angle, return to step 2 until the DOA estimation of the acoustic target is completed; where n3 is an integer greater than 1.

[0016] Further, in step 3, the spatial spectrum peak intensity of the real-time search signal is calculated using the following formula:

[0017]

[0018] in, To search for the spatial spectrum peak intensity of the signal in real time, in dB; Let i be the i-th element of the acoustic target spatial spectrum, where i is an integer and i > 0.

[0019] Further, in step 3, the signal power of the real-time search signal is calculated using the following formula:

[0020]

[0021] in, The signal power for real-time search signals, expressed in watts (W). N represents the number of data points for the real-time search signal.

[0022] Furthermore, in step 1, the spatial spectrum search range and spatial resolution for the different search states are respectively set as follows:

[0023] The spatial spectrum search range for the targetless search state is [0°, 180°] or [0°, 359°], with a spatial resolution of 5°≤θ. 无目标 <20°; When the DOA detector array is a linear array, the spatial spectrum search range in the targetless search state is [0°, 180°]; When the DOA detector array is a circular array or other spatial array, the spatial spectrum search range in the targetless search state is [0°, 359°];

[0024] The spatial spectrum search range for the suspected target search state is [θ1-Δθ, θ1+Δθ], with a spatial resolution of 2°≤θ. 发现疑似目标 <5°, where θ1 is the acoustic target direction of arrival of the last output before the search state is updated to a suspected target, Δθ is the change in the spatial spectrum search range, and Δθ > v max v max The angle of maximum change;

[0025] The spatial spectrum search range for the stable tracking target search state is [θ2-v]. max θ2+v max The spatial resolution is 0.5°≤θ. 稳定跟踪目标 <2°, where θ2 is the acoustic target arrival direction of the last output before the search state is updated to a stable tracking target.

[0026] Furthermore, in step 1, Δθ is 20°-50°.

[0027] Furthermore, in step 4, n1 is 3-10;

[0028] In step 6, n2 is 10-20;

[0029] In step 8, n3 is 5-10.

[0030] Furthermore, in step 1, the spatial spectrum noise floor is 0.01 dB, and the signal power threshold is 1.2 × 10⁻⁶. -7 W.

[0031] Furthermore, in step 1, the initial parameters also include the direction-of-arrival output frequency, the signal sampling frequency, the signal frequency range and number of characteristic frequency points estimated by DOA, as well as the block size, frame size and window overlap rate of the signal processing.

[0032] Further, in step 1, the signal frequency range estimated by DOA is [100Hz, 5000Hz], the number of characteristic frequency points is 1-20, and the frame size of signal processing is 2. 5 -2 13 The window overlap rate for signal processing is 0.75.

[0033] The block size for signal processing is calculated using the following formula:

[0034] n block =f s ×1 / f DOA

[0035] Where, n block f is the block size for signal processing. s f is the signal sampling frequency. DOA The output frequency is the direction of arrival.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The present invention provides a high-resolution, high-real-time acoustic target direction of arrival (DOA) estimation method, which divides the search state of DOA estimation into three search states: no target, suspected target found, and stable target tracking. For different search states, different spatial spectrum search ranges and spatial resolutions are set to avoid data redundancy and improve the real-time performance of DOA estimation. At the same time, by adjusting the spatial spectrum search range and spatial resolution of different search states, the accuracy of DOA estimation can be improved.

[0038] 2. The present invention provides a high-resolution, high-real-time acoustic target direction of arrival estimation method. Based on physical priors, the maximum change angle of acoustic target motion is determined. Under the stable target tracking search state, the spatial spectrum search range of the acoustic target is small and the accuracy is high. Due to the influence of random noise and other factors, the acoustic target direction of arrival estimated by DOA may produce large fluctuations that do not conform to physical common sense, that is, much higher than the maximum change angle of acoustic target motion. When such large fluctuations are detected, the search state is updated to the target-free search state by accumulating counts, thereby expanding the spatial spectrum search range and effectively avoiding the problem of acoustic target loss due to data fluctuations.

[0039] 3. The present invention provides a high-resolution, high-real-time acoustic target direction-of-arrival (DOA) estimation method. In the absence of a target, it employs a large spatial spectrum search range and low spatial resolution to quickly determine the coarse DOA of the acoustic target. In the presence of a suspected target, it appropriately narrows the spatial spectrum search range and appropriately increases the spatial resolution to obtain a more accurate DOA. In the stable tracking target search, it determines the maximum change angle of the acoustic target's motion based on physical priors, significantly narrowing the spatial spectrum search range and significantly increasing the spatial resolution, thereby improving the accuracy of DOA estimation and achieving high-precision estimation of the acoustic target's DOA. Attached Figure Description

[0040] Figure 1 This is a flowchart of a method according to an embodiment of the present invention;

[0041] Figure 2 This is a simulation diagram of the search state change in an embodiment of the present invention;

[0042] Figure 3 This is a simulation diagram of the acoustic target direction of arrival output in an embodiment of the present invention. Detailed Implementation

[0043] The high-resolution, high-real-time acoustic target direction-of-arrival estimation method proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of this invention and are not intended to limit the scope of protection of this invention.

[0044] A high-resolution, high-real-time acoustic target direction-of-arrival estimation method, such as Figure 1 As shown, it includes the following steps:

[0045] Step 1: Set the initial parameters for DOA estimation, then divide the search states for DOA estimation into no target, suspected target discovery, and stable target tracking, and set the spatial spectrum search range [θ] for different search states. min θ maxThe initial parameters include basic parameters, outlier detection parameters, signal processing parameters, and target detection parameters. The spatial resolution θ is used for DOA estimation.

[0046] Basic parameters include the signal sampling frequency f. s The signal frequency range estimated by DOA [f] min f max and the number of characteristic frequency points n fre and the output frequency f in the direction of arrival DOA The real-time search signal is acquired by the DOA probe array, with a signal sampling frequency f. s The signal sampling rate of the DOA probe array is set according to different hardware. In this embodiment, the signal frequency range estimated by the DOA is [f min f max Take [100Hz, 5000Hz], and the number of characteristic frequency points n fre The number of characteristic frequency points n in this embodiment is 1-20. fre Setting the value to 20 indicates selecting 20 equally spaced characteristic frequency points within the signal frequency range, and performing DOA estimation at each characteristic frequency point. The direction-of-arrival output frequency f... DOA The value is 10Hz, indicating that the DOA estimation is performed based on the real-time search signal acquired by the DOA detection array every 100ms, and the acoustic target direction of arrival is obtained and output.

[0047] The outlier detection parameter is the maximum change angle v. max During the motion of the acoustic target, the direction of arrival (DOA) of the acoustic target, as estimated by DOA, should change continuously, with the maximum change angle being v. max A range for the change in the direction of arrival (DOA) of an acoustic target, determined based on physical priors, is set. If the change in DOA obtained from two consecutive DOA estimations exceeds the maximum change angle v... max The established physical priors can be used to assume that the acoustic target direction of arrival obtained from this DOA estimation is abnormal.

[0048] Signal processing parameters include the block size n of signal processing. block Frame size n frame The window overlap ratio. Signal processing block size n. block This indicates the number of data points used in a single output acoustic target direction of arrival, based on the signal sampling frequency f. s and the output frequency f in the direction of arrival DOA Calculations show that The frame size n for signal processing frame 2 5 -2 13 , representing the number of data points used in a single generation of the acoustic target spatial spectrum; in this embodiment, it is taken as 2.12 =4096. The window overlap rate in signal processing represents the repetition rate of data points when generating the acoustic target spatial spectrum twice. In this embodiment, it is set to 0.75.

[0049] Target detection parameters include spatial spectrum background noise P noise and signal power threshold E noise Spatial spectrum background noise P noise This represents the spatial spectral intensity generated when there are no acoustic targets in the environment where the DOA detector array is located; in this embodiment, it is taken as 0.01 dB. Signal power threshold E noise This represents the mean time-domain power of the received signal when there are no acoustic targets in the environment where the DOA detector array is located. This value is derived from statistical analysis of a large amount of prior data, and in this embodiment, it is taken as 1.2 × 10⁻⁶. -7 W.

[0050] In this embodiment, the spatial spectrum search range [θ] for different search states min θ max The spatial resolution θ is set as follows:

[0051] The spatial spectrum search range for the targetless search state is [0°, 180°], and the spatial resolution is 5°.

[0052] The spatial spectrum search range for the suspected target search state is [θ1-20°, θ1+20°], with a spatial resolution of 2°. Here, θ1 is the direction of arrival of the acoustic target wave output at the last time before the search state is updated to a suspected target.

[0053] The spatial spectrum search range for the stable tracking target search state is [θ2-v]. max θ2+v max The spatial resolution is 0.5°, where θ2 is the direction of arrival of the acoustic target wave in the last output before the search state is updated to a stable tracking target.

[0054] Step 2: Set the search state to targetless, acquire the real-time search signal, and perform spatial spectrum search and DOA estimation according to the spatial spectrum search range [0°, 180°] and spatial resolution of 5° in the targetless search state. Obtain the acoustic target spatial spectrum and acoustic target direction of arrival, and output the acoustic target direction of arrival.

[0055] Step 3: Calculate the signal power E of the real-time search signal. block Based on the spatial spectrum of the acoustic target, the peak intensity P of the spatial spectrum of the real-time search signal is calculated. peak .

[0056] The signal power E of the real-time search signal is calculated using the following formula. block :

[0057]

[0058] in, N represents the number of data points for the real-time search signal.

[0059] The spatial spectral peak intensity P of the real-time search signal is calculated using the following formula. peak :

[0060]

[0061] in, Let i be the i-th element of the acoustic target spatial spectrum, where i is an integer and i > 0.

[0062] Step 4: Repeat steps 2-3. If the spatial spectrum peak intensity P of the real-time search signal is obtained continuously for n1 times... peak Greater than the spatial spectrum background noise P noise And signal power E block Greater than the signal power threshold E noise Then proceed to step 5. Here, n1 is an integer greater than 1; in this embodiment, n1 = 3.

[0063] Step 5: Update the search status to "suspected target found", continue to acquire real-time search signals, and perform spatial spectrum search and DOA estimation based on the real-time search signals according to the spatial spectrum search range [θ1-20°, θ1+20°] and spatial resolution of 2° of the suspected target found search status, and obtain and output the acoustic target wave direction of arrival.

[0064] Step 6: Repeat step 5. If the change θ between the acoustic target direction of arrival obtained from two consecutive DOA estimations is n2 times... t -θ t-1 Less than or equal to the maximum change angle v max Then proceed to step 7. Where n2 is an integer greater than 1, θ t θ represents the direction of arrival (DOA) of the acoustic target obtained from this DOA estimation. t-1 This represents the acoustic target direction of arrival obtained from the previous DOA estimation. In this embodiment, n2=10.

[0065] Step 7: Update the search status to a stable tracking target, continue acquiring real-time search signals, and search within the spatial spectrum range [θ2-v] of the stable tracking target search status. max θ2+v max With a spatial resolution of 0.5°, spatial spectrum search and DOA estimation are performed based on the real-time search signal to obtain and output the acoustic target's direction of arrival.

[0066] Step 8: Repeat step 7. If the change θ between the acoustic target direction of arrival obtained from two consecutive DOA estimations is n3 times... t -θ t-1 Greater than the maximum change angle v max If the condition is met, return to step 2 until the direction of arrival estimation of the acoustic target is completed. Here, n3 is an integer greater than 1; in this embodiment, n3 = 5.

[0067] In brief, in this embodiment, the logic for updating the search status is as follows:

[0068] 1) In the state of no target search, when the spatial spectrum peak intensity P of the real-time search signal... peak and signal power E block It consistently outperforms the spatial spectrum background noise P in n1 consecutive DOA estimates. noise and signal power threshold E noise If the search status is updated to "suspected target found", the spatial spectrum search range [θ] will be expanded. min θ max The spatial resolution θ is reduced to 2° by decreasing it to [θ1-20°, θ1+20°].

[0069] 2) In the state of searching for a suspected target, when the change between the acoustic target direction of arrival obtained from two consecutive n2 consecutive DOA estimates is less than or equal to the maximum change angle v max At that time, the search state is updated to a stable target tracking search state, and the spatial spectrum search range [θ] is increased. min θ max Decrease to [θ2-v] max θ2+v max This reduces the spatial resolution θ to 0.5°.

[0070] 3) Under stable target tracking search conditions, when the change between the acoustic target direction of arrival obtained from two consecutive n3 consecutive DOA estimates is greater than the maximum change angle v max When this happens, the search status is updated to a targetless search state, and the spatial spectrum search range [θ] is expanded. min θ max Expanding to [0°, 180°] increases the spatial resolution θ to 5°.

[0071] Simulations were performed on the high-resolution, high-real-time acoustic target direction-of-arrival estimation method provided in this embodiment, and the results were obtained. Figure 2 , Figure 3 The simulation results, such as Figure 2 , Figure 3As shown, when the acoustic target moves and the direction of arrival of the acoustic target changes drastically, the search state is immediately updated from stable target tracking to no target; when a suspected target is detected, the search state is then updated to detected suspected target, thereby achieving effective detection of the direction of arrival of the acoustic target.

[0072] This invention provides a high-resolution, high-real-time acoustic target DOA estimation method based on the MUSIC algorithm. It divides the search states for acoustic target DOA estimation into three categories: no target, suspected target discovery, and stable target tracking. By dynamically adjusting the spatial spectrum search range and spatial resolution for different search states, data redundancy can be avoided, improving the accuracy and real-time performance of acoustic target DOA estimation. In the no-target search state, this invention employs a large spatial spectrum search range and low spatial resolution to quickly determine the coarse DOA of the acoustic target. In the suspected target discovery search state, the spatial spectrum search range is appropriately reduced, and the spatial resolution is appropriately increased to obtain a more accurate acoustic target DOA. In the stable target tracking search state, based on physical priors, the maximum change angle of the acoustic target's motion is determined, significantly reducing the spatial spectrum search range and significantly increasing the spatial resolution, thereby improving the accuracy of acoustic target DOA estimation and achieving high-precision estimation of the acoustic target's DOA.

Claims

1. A high-resolution, high-real-time method for estimating the direction of arrival (DOA) of an acoustic target, characterized in that, Includes the following steps: Step 1: Set the initial parameters for DOA estimation, then divide the search states of DOA estimation into no target, suspected target found, and stable target tracking, and set the spatial spectrum search range and spatial resolution for different search states; the DOA estimation adopts the MUSIC algorithm, and the initial parameters include the maximum change angle, spatial spectrum background noise, and signal power threshold; Step 2: Set the search state to targetless, acquire the real-time search signal, and perform spatial spectrum search and DOA estimation based on the real-time search signal according to the spatial spectrum search range and spatial resolution of the targetless search state, to obtain the acoustic target spatial spectrum and acoustic target direction of arrival and output the acoustic target direction of arrival. Step 3: Calculate the signal power of the real-time search signal, and calculate the peak intensity of the spatial spectrum of the real-time search signal based on the acoustic target spatial spectrum. Step 4: Repeat steps 2-3. If the peak intensity of the spatial spectrum of the real-time search signal acquired in n1 consecutive times is greater than the spatial spectrum noise floor and the signal power is greater than the signal power threshold, then proceed to step 5; where n1 is an integer greater than 1. Step 5: Update the search status to "suspected target found", continue to acquire real-time search signals, and perform spatial spectrum search and DOA estimation based on the real-time search signals according to the spatial spectrum search range and spatial resolution of the suspected target found search status, to obtain and output the acoustic target direction of arrival. Step 6: Repeat step 5. If the change between the acoustic target direction of arrival obtained from two consecutive DOA estimates is less than or equal to the maximum change angle, then proceed to step 7; where n2 is an integer greater than 1. Step 7: Update the search status to a stable tracking target, continue to acquire real-time search signals, and perform spatial spectrum search and DOA estimation based on the real-time search signals according to the spatial spectrum search range and spatial resolution of the stable tracking target search status, to obtain and output the acoustic target direction of arrival. Step 8: Repeat step 7. If the change between two consecutive DOA estimates of the acoustic target is greater than the maximum change angle, return to step 2 until the DOA estimation of the acoustic target is completed; where n3 is an integer greater than 1.

2. The high-resolution high-real-time acoustic target DOA estimation method according to claim 1, characterized in that, In step 3, the spatial spectrum peak intensity of the real-time search signal is calculated using the following formula: ； wherein is the spatial spectrum peak intensity of the real-time search signal in dB; is the i-th element of the acoustic target spatial spectrum, i is an integer, and i >

0.

3. The high-resolution high-real-time acoustic target DOA estimation method according to claim 2, characterized in that, In step 3, the signal power of the real-time search signal is calculated using the following formula: ； wherein, is the signal power of the real-time search signal, in W; is the real-time search signal, and N is the number of data points of the real-time search signal.

4. The high-resolution high-real-time acoustic target DOA estimation method according to any one of claims 1-3, characterized in that, In step 1, the spatial spectrum search range and spatial resolution for the different search states are set as follows: The spatial spectrum search range of the no-target search state is [0°, 180°] or [0°, 359°], and the spatial resolution is 5°≤θ 无目标 <20°; The spatial spectrum search range for the suspected target search state is [θ1-Δθ, θ1+Δθ], with a spatial resolution of 2°≤θ. 发现疑似目标 <5°, where θ1 is the acoustic target direction of arrival of the last output before the search state is updated to a suspected target, Δθ is the change in the spatial spectrum search range, and Δθ > v max v max The angle of maximum change; The spatial spectrum search range for the stable tracking target search state is [θ2-v]. max θ2+v max The spatial resolution is 0.5°≤θ. 稳定跟踪目标 <2°, where θ2 is the acoustic target arrival direction of the last output before the search state is updated to a stable tracking target.

5. The high-resolution high-real-time acoustic target DOA estimation method according to claim 4, characterized in that: In step 1, Δθ is 20°-50°.

6. The high-resolution high-real-time acoustic target DOA estimation method according to claim 5, characterized in that: In step 4, n1 is 3-10; In step 6, n2 is 10-20; In step 8, n3 is 5-10.

7. The high-resolution high-real-time acoustic target DOA estimation method according to claim 6, characterized in that: In step 1, the spatial spectrum noise floor is 0.01 dB, and the signal power threshold is 1.2 × 10⁻⁶. -7 W.

8. The high-resolution, high-real-time acoustic target direction-of-arrival estimation method according to claim 7, characterized in that: In step 1, the initial parameters also include the direction-of-arrival output frequency, the signal sampling frequency, the signal frequency range and number of characteristic frequency points estimated by DOA, as well as the block size, frame size and window overlap rate of the signal processing.

9. The high-resolution high-real-time acoustic target DOA estimation method according to claim 8, characterized in that: In step 1, the signal frequency range estimated by DOA is [100Hz, 5000Hz], the number of characteristic frequency points is 1-20, and the frame size for signal processing is 2. 5 -2 13 The window overlap rate for signal processing is 0.

75. The block size for signal processing is calculated using the following formula: n block = f s ×1 / f DOA ; where n block is the block size of the signal processing, f s is the signal sampling frequency, f DOA is the direction of arrival output frequency.

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