CN103135092A - Micro aperture acoustic array moving objective orientation method - Google Patents

Abstract

利用流型矩阵和传声器阵列信号之间的数学关系，通过角度搜索方式得到运动目标的方位角估计。本发明利用流型矩阵与传声器信号的正交关系，进行方位角搜索，即可得到运动目标的有效方位角估计，在保证定向精度不变的前提下，极大的减小了运动目标方位角估计所需要的运算复杂度。The invention relates to a method for orienting a moving target with a micro-aperture acoustic array, comprising the following steps: selecting a microphone array, and determining the signal bandwidth B=f _H -f _L of the moving target, wherein f _H is the highest value of the signal bandwidth, and f _L is The lowest value of the signal bandwidth; determine the flow pattern matrix, so that the frequency parameter of the flow pattern matrix

Using the mathematical relationship between the flow pattern matrix and the microphone array signal, the azimuth angle estimation of the moving target is obtained by means of angle search. The present invention uses the orthogonal relationship between the flow pattern matrix and the microphone signal to search for the azimuth angle, and then the effective azimuth angle estimation of the moving target can be obtained, and the azimuth angle of the moving target can be greatly reduced under the premise of ensuring that the orientation accuracy remains unchanged. Estimate the required computational complexity.

Description

A micro-aperture acoustic array moving target orientation method

technical field

The invention relates to the technical field of array signal processing, in particular to a micro-aperture acoustic array moving target orientation method.

Background technique

Target orientation methods are widely used in radar, sonar, ground unattended sensor networks and other fields. The acoustic signals generated by main moving targets such as wheeled vehicles, tracked vehicles, and low-altitude aircraft are typical broadband random signals. At present, the orientation methods for broadband random signals mainly include: 1. Orientation methods based on incoherent signals 2. Orientation methods based on coherent signals Method 3. Maximum likelihood method for broadband sound sources. Among them, the orientation method based on incoherent signals needs to decompose the wideband signal into narrowband data on non-overlapping frequency bands, and process each narrowband separately to obtain azimuth estimation. This method has simple ideas, but poor accuracy and high computational complexity. ; The orientation method based on coherent signals needs to focus the signal space on the non-overlapping frequency points in the frequency band to the reference frequency point, and obtain the data covariance of a single frequency point after focusing, and then use the narrowband signal processing method to estimate the azimuth angle. The method either requires pre-estimation or a complex focusing method, which is complex and has a large computational complexity; the maximum likelihood method for broadband sound sources has high computational accuracy and a wide range of applications, but the computational complexity is huge, which largely limits its widespread use.

Contents of the invention

The technical problem to be solved by the present invention is to provide a micro-aperture acoustic array moving target orientation method, which can reduce the computational complexity under the premise of keeping the orientation accuracy unchanged.

The technical solution adopted by the present invention to solve the technical problem is to provide a micro-aperture acoustic array moving target orientation method, comprising the following steps:

(1) Select the microphone array and determine the signal bandwidth of the moving target B=f _H -f _L , where f _H is the highest value of the signal bandwidth, and f _L is the lowest value of the signal bandwidth;

(2) Determine the flow pattern matrix, so that the frequency parameter of the flow pattern matrix

(3) Using the mathematical relationship between the flow pattern matrix and the microphone array signal, the azimuth angle estimation of the moving target is obtained by means of angle search.

其中，V_sound为声速。In the step (1), the maximum aperture D of the microphone array and the signal bandwidth B of the moving target satisfy

Among them, V _sound is the speed of sound.

The frequency parameter f of the flow pattern matrix in the step (2) satisfies the normalized frequency spectrum of the signal broadband so that the standard deviation of its probability density function is the smallest.

In the step (3), a multi-signal classification algorithm, a beamforming algorithm, a maximum likelihood algorithm or a maximum entropy algorithm is used to realize the angle search method to obtain the azimuth angle estimation of the moving target.

The microphone array in the step (1) is a linear array, a circular array, a planar array or a triangular array.

Beneficial effect

Due to the adoption of the above-mentioned technical scheme, the present invention has the following advantages and positive effects compared with the prior art: the present invention utilizes the orthogonal relationship between the flow pattern matrix and the microphone signal to search for the azimuth angle, and the moving target can be obtained. Effective azimuth estimation. The orientation method of the present invention does not need to separately estimate the azimuth angle for each frequency point, and does not need to focus the frequency to the reference frequency before performing the azimuth angle estimation, thereby greatly reducing the computational complexity. The present invention greatly reduces the computational complexity required for the estimation of the azimuth angle of the moving target under the premise of ensuring that the orientation accuracy remains unchanged.

Detailed ways

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Embodiments of the present invention relate to a method for orienting a moving target with a micro-aperture acoustic array, comprising the following steps:

其中，V_sound为声速。保证

可以使得所述的流型矩阵A与传声器信号的数学关系的不变性，并且

的值越小所得的方位角估计结果越准确。传声器阵列可以是但不限于如下类型：线阵、圆阵、平面阵、三角阵。(1) Select the microphone array and determine the signal bandwidth of the moving target B=f _H -f _L , where f _H is the highest value of the signal bandwidth, and f _L is the lowest value of the signal bandwidth. Among them, the maximum aperture D of the microphone array and the signal bandwidth B of the moving target satisfy

Among them, V _sound is the speed of sound. ensure

The invariance of the mathematical relationship between the flow pattern matrix A and the microphone signal can be made, and

The smaller the value of , the more accurate the azimuth estimation result is. The microphone array can be of but not limited to the following types: linear array, circular array, planar array, triangular array.

其中，流型矩阵的频率参数f满足信号宽带的归一化频谱使得其概率密度函数标准差最小时，方位角估计精度最高，该方法定向效果最佳。流型矩阵A=[a₁(ω₀)a₂(ω₀)...a_n(ω₀)]，其中， $a_i\left({\mathrm{\ω}}_0\right)=\left(\begin{array}{c}{e}^{-j{\mathrm{\ω}}_0{\mathrm{\τ}}_{1i}}\\ e^{-j{\mathrm{\ω}}_0{\mathrm{\τ}}_{2i}}\\ ...\\ e^{-j{\mathrm{\ω}}_0{\mathrm{\τ}}_{\mathrm{Mi}}}\end{array}\right),$ i=1,2,...,n(2) Determine the flow pattern matrix, so that the frequency parameter of the flow pattern matrix

Among them, when the frequency parameter f of the flow pattern matrix satisfies the normalized spectrum of the signal broadband so that the standard deviation of the probability density function is the smallest, the azimuth angle estimation accuracy is the highest, and the orientation effect of this method is the best. Flow pattern matrix A=[a ₁ (ω ₀ )a ₂ (ω ₀ )...a _n (ω ₀ )], where, $a_i\left({\mathrm{\ω}}_0\right)=\left(\begin{array}{c}{e}^{-j{\mathrm{\ω}}_0{\mathrm{\τ}}_{1i}}\\ e^{-j{\mathrm{\ω}}_0{\mathrm{\τ}}_{2i}}\\ ...\\ e^{-j{\mathrm{\ω}}_0{\mathrm{\τ}}_{\mathrm{Mi}}}\end{array}\right),$ i=1,2,...,n

. In the formula, ω ₀ =2×π×f, for a uniform circular array with the center of the circle as the reference point: τ _ki =r/V _sound (cos(2(k-1)-θ _i )cosφ _i ),k=1, 2,...,M, where _θi and _φi represent the azimuth and elevation angles, respectively, and r is the radius of the circle.

(3) Using the mathematical relationship between the flow pattern matrix and the microphone array signal, the azimuth angle estimation of the moving target is obtained by means of angle search. Among them, when the multi-signal classification method is selected, the mathematical relationship between the flow pattern matrix and the microphone array signal is that the steering vector a _i (ω ₀ ) in the flow pattern matrix is orthogonal to the noise subspace of the sensor array signal. This step can use but not limited to the following methods to realize the angle search method to obtain the azimuth estimation of the moving target, multi-signal classification algorithm, beam forming algorithm, maximum likelihood algorithm and maximum entropy algorithm.

It should be noted that, for different algorithms, the above-mentioned mathematical relationship is also different. When the multi-signal classification algorithm in the following specific embodiments is used, the relationship between the flow pattern matrix and the microphone array signal is orthogonal.

The present invention will be further described below with a specific embodiment.

1. A four-element circular array microphone array is selected, the aperture D of the circular array is 0.04m, and the sound velocity V _sound in the air is 340m/s.

满足小于1/20的条件。此时流型矩阵A的频率参数f可以选择为200Hz。2. The signal bandwidth B of the main target wheeled vehicles, crawler vehicles and low-altitude aircraft can be limited to 0-400Hz. At this time,

Satisfy the condition of less than 1/20. At this time, the frequency parameter f of the flow pattern matrix A can be selected as 200 Hz.

3. After determining the flow pattern matrix A, search the MUSIC spectrum of the above-mentioned target signal to achieve effective orientation to the target. It is worth mentioning that the microphone arrays in the above embodiments can also be linear arrays, planar arrays, and triangular arrays, and the methods for achieving effective orientation to targets can also be beamforming algorithms, maximum likelihood algorithms, and maximum entropy algorithms.

Use Matlab software to simulate the above method, and compare the running time of other broadband object orientation methods. The results are shown in the following table:

Note: TCT is a typical coherent signal processing method

It is not difficult to find that the present invention uses the orthogonal relationship between the flow pattern matrix and the microphone signal to search for the azimuth angle, so as to obtain the effective azimuth angle estimation of the moving target. The orientation method of the present invention does not need to separately estimate the azimuth angle for each frequency point, and does not need to focus the frequency to the reference frequency before performing the azimuth angle estimation, thereby greatly reducing the computational complexity. The present invention greatly reduces the computational complexity required for the estimation of the azimuth angle of the moving target under the premise of ensuring that the orientation accuracy remains unchanged.

Claims (5)

1. a micropore diameter acoustic array moving target orientation method, is characterized in that, comprises the following steps:

(1) select microphone array, determine the signal bandwidth B=f of moving target _H-f _L, wherein, f _HBe the mxm. of signal bandwidth, f _LMinimum for signal bandwidth;

(2) determine the flow pattern matrix, make the frequency parameter of flow pattern matrix

(3) utilize mathematical relation between flow pattern matrix and microphone array column signal, the position angle that obtains moving target by the angle searching mode is estimated.

2. micropore diameter acoustic array moving target orientation method according to claim 1, is characterized in that, satisfies between the signal bandwidth B of the maximum diameter of hole D of microphone array and moving target in described step (1)

Wherein, V _SoundBe the velocity of sound.

3. micropore diameter acoustic array moving target orientation method according to claim 1, is characterized in that, the normalization frequency spectrum that the frequency parameter f of the flow pattern matrix in described step (2) satisfies the signal broadband makes its probability density function standard deviation minimum.

4. micropore diameter acoustic array moving target orientation method according to claim 1, it is characterized in that, adopt multi-signal sorting algorithm in described step (3), beamforming algorithm, maximum likelihood algorithm or maximum entropy algorithm realize that the angle searching mode obtains the position angle estimation of moving target.

5. micropore diameter acoustic array moving target orientation method according to claim 1, is characterized in that, the microphone array in described step (1) is classified linear array, circle battle array, planar array or triangle battle array as.