阅读说明：本技术 基于差分优化的四面体阵目标方位估计方法 (Tetrahedral array target orientation estimation method based on differential optimization ) 是由 师俊杰 孙大军 梅继丹 吕云飞 兰华林 滕婷婷 靳建嘉 于 2020-04-14 设计创作，主要内容包括：一种基于差分优化的四面体阵目标方位估计方法,属于水声目标方位估计技术领域。本发明针对利用声强估计方法估计目标声源方位,存在冗余声学信息利用不足的问题。包括将四基元接收的声压时域信号转换为对应的频域信号；再分别由四面体阵模型中选取三基元作为预处理单元,获得四个不相重复的预处理单元；对每个预处理单元对应的三个频域信号分别进行预处理,共获得沿直角坐标系相应坐标轴方向波数的八个线性方程；求解得到直角坐标系三个坐标轴方向波数的相关稳健估计；根据所述波数的相关稳健估计计算获得目标方位角和目标俯仰角,从而实现对目标方位的估计。本发明利用最小二乘优化思想将线性方程组超定化来提升四面体阵目标方位估计的稳健性。(A tetrahedral array target orientation estimation method based on differential optimization belongs to the technical field of underwater acoustic target orientation estimation. The invention aims at the problem that redundant acoustic information is not sufficiently utilized when a sound intensity estimation method is used for estimating the target sound source position. The method comprises the steps of converting sound pressure time domain signals received by four elements into corresponding frequency domain signals; respectively selecting three primitives from the tetrahedral array model as preprocessing units to obtain four nonrepeating preprocessing units; respectively preprocessing the three frequency domain signals corresponding to each preprocessing unit to obtain eight linear equations of wave numbers along the corresponding coordinate axis direction of the rectangular coordinate system; solving to obtain the relevant robust estimation of wave numbers in three coordinate axis directions of the rectangular coordinate system; and calculating to obtain a target azimuth angle and a target pitch angle according to the correlation robust estimation of the wave number, thereby realizing the estimation of the target azimuth. The method utilizes the least square optimization idea to overdetermine the linear equation set to improve the robustness of the tetrahedral array target orientation estimation.)

1. A tetrahedral array target orientation estimation method based on differential optimization is characterized in that a tetrahedral array comprises a tetrahedral array model formed by adopting four acoustic hydrophones as four elements, wherein the tetrahedral array model is used for receiving underwater plane wave acoustic pressure time domain signals;

the target position estimation method comprises the following steps:

the method comprises the following steps: converting the sound pressure time domain signals received by the four elements into corresponding frequency domain signals;

step two: selecting three primitives from the tetrahedral array model as preprocessing units respectively to obtain four non-repetitive preprocessing units; respectively preprocessing the three frequency domain signals corresponding to each preprocessing unit to obtain eight linear equations of wave numbers along the corresponding coordinate axis direction of the rectangular coordinate system;

step three: solving the eight linear equations by using a least square optimization idea to obtain relevant robust estimation of wave numbers in three coordinate axis directions of the rectangular coordinate system;

step four: and calculating to obtain a target azimuth angle and a target pitch angle according to the correlation robust estimation of the wave number, thereby realizing the estimation of the target azimuth.

2. The tetrahedral array target orientation estimation method based on differential optimization according to claim 1, wherein the four primitives are set to A, B, C, D respectively and form a tetrahedral array model ABCD;

in the step one, sound pressure time domain signals received by four elements are p in sequence₁(t)、p₂(t)、p₃(t) and p₄(t) for p₁(t)、p₂(t)、p₃(t) and p₄(t) performing fast Fourier transform to obtain a corresponding frequency domain signal P₁(f)、P₂(f)、P₃(f) And P₄(f)。

3. The tetrahedral array target orientation estimation method based on differential optimization according to claim 2,

and step two, the rectangular coordinate system comprises a rectangular coordinate system xyz established by taking the center O of the tetrahedral array model as an origin, wherein the z axis is along the OD direction, the y axis is parallel to BC, and the x axis meets the right-hand coordinate system.

4. The tetrahedral array target orientation estimation method based on difference optimization according to claim 3, wherein the four non-repetitive preprocessing units comprise a preprocessing unit composed of ABC surface three elements, and the corresponding frequency domain signal is P₁(f)、P₂(f) And P₃(f) The pretreatment comprises:

to P₁(f)、P₂(f) Arithmetically summing to obtain P₁₂(f) To P₁(f) And P₃(f) Arithmetically summing to obtain P₁₃(f) (ii) a To P₁(f) And P₂(f) Calculating an arithmetic difference to obtain V₁₂(f) To P₁(f) And P₃(f) Calculating an arithmetic difference to obtain V₁₃(f)；

To P₁₂(f) And V₁₃(f) Carrying out conjugate multiplication to obtain P₁₂(f)And takes its real part, which is recorded asTo V₁₂(f) And P₁₃(f) Carrying out conjugate multiplication to obtain V₁₂(f)And takes its real part, which is recorded asTo P₁₂(f) And P₁₃(f) Carrying out conjugate multiplication to obtain P₁₂(f)And takes its real part, which is recorded as

To findThe wave number k in the x-axis and y-axis directions is obtained_xAnd k_yLinear equation one of (1);

to findThe wave number k in the x-axis and y-axis directions is obtained_xAnd k_yThe second linear equation of (2);

then, the pretreatment is carried out on a pretreatment unit consisting of three elements of the ABD surface to obtain wave numbers k in the directions of the x axis and the y axis_xAnd k_yAnd the wave number k in the x-axis and z-axis directions_xAnd k_zThe linear equation of (4);

then, the preprocessing unit composed of three primitives of the ACD surface is preprocessed to obtain wave numbers k in the directions of the x axis and the y axis_xAnd k_yAnd the linear equation of five, and the wave numbers k in the x-axis and z-axis directions_xAnd k_zThe linear equation of (a);

then respectively carrying out the pretreatment on a pretreatment unit consisting of three elements of the BCD surface to obtain wave numbers k in the directions of the x axis, the y axis and the z axis_x、k_yAnd k_zSeven and eight linear equations.

5. The tetrahedral array target orientation estimation method based on differential optimization according to claim 4,

setting the matrix A as:

the matrix x is:

x＝[k_xk_yk_z]^T；

in step three, the eight linear equations are solved by using the least square optimization idea, and the obtained correlation robust estimation includes:

in the formula P₁₄Represents a pair P₁(f)、P₄(f) Arithmetically summing the obtained P₁₄(f)，V₁₄Represents a pair P₁(f)、P₄(f) V obtained by arithmetic difference₁₄(f)，P₂₄Represents a pair P₂(f)、P₄(f) Arithmetically summing the obtained P₂₄(f)，P₃₄Represents a pair P₃(f)、P₄(f) Arithmetically summing the obtained P₃₄(f)，V₂₄Represents a pair P₂(f)、P₄(f) V obtained by arithmetic difference₂₄(f)，V₃₄Represents a pair P₃(f)、P₄(f) V obtained by arithmetic difference₃₄(f) (ii) a d represents the distance between any two primitives;

and then based on the least square optimization idea, obtaining:

6. the tetrahedral array target orientation estimation method based on differential optimization according to claim 5,

the target azimuth angle θ in the fourth step is:

θ＝atan2(k_y/k_x)；

target pitch angleComprises the following steps:

Technical Field

The invention relates to a tetrahedral array target orientation estimation method based on differential optimization, belonging to the technical field of underwater acoustic target orientation estimation.

Background

An underwater small sonar platform such as a small Unmanned Underwater Vehicle (UUV), a glider and the like is limited in number of elements or geometric size of an acoustic array due to space mounting capacity or special acoustic requirements. The tetrahedron array is used as an acoustic sensing configuration commonly used for an underwater small sonar platform, and the target parameter acquisition capability of the tetrahedron array is always concerned by underwater acoustics.

In the existing target azimuth estimation methods based on tetrahedral arrays (or similar tetrahedral arrays), one is target azimuth estimation under a five-membered volume array low signal-to-noise ratio, and the method provides a minimum variance undistorted response azimuth estimation method based on cross-correlation processing, improves target azimuth estimation performance by utilizing a virtual array idea of cross-correlation processing among elements, and has the defect of large data processing calculated amount; in addition, performance analysis and optimization of a quaternary orthogonal array sound intensity direction vector estimation method are provided, and the estimation of the target sound source azimuth is realized by using a sound intensity estimation method (sound pressure difference approximate particle vibration velocity); the method utilizes the direction vector of sound intensity to improve the target direction estimation performance, and has the defect of insufficient utilization of redundant acoustic information.

Disclosure of Invention

The invention provides a tetrahedral array target orientation estimation method based on differential optimization, aiming at the problem that redundant acoustic information is not sufficiently utilized when the sound intensity estimation method is used for estimating the orientation of a target sound source in the existing target orientation estimation method.

The invention relates to a tetrahedral array target orientation estimation method based on differential optimization, wherein a tetrahedral array comprises a tetrahedral array model formed by adopting four acoustic hydrophones as four elements, and the tetrahedral array model is used for receiving underwater plane wave acoustic pressure time domain signals;

the target position estimation method comprises the following steps:

the method comprises the following steps: converting the sound pressure time domain signals received by the four elements into corresponding frequency domain signals;

step two: selecting three primitives from the tetrahedral array model as preprocessing units respectively to obtain four non-repetitive preprocessing units; respectively preprocessing the three frequency domain signals corresponding to each preprocessing unit to obtain eight linear equations of wave numbers along the corresponding coordinate axis direction of the rectangular coordinate system;

step three: solving the eight linear equations by using a least square optimization idea to obtain relevant robust estimation of wave numbers in three coordinate axis directions of the rectangular coordinate system;

step four: and calculating to obtain a target azimuth angle and a target pitch angle according to the correlation robust estimation of the wave number, thereby realizing the estimation of the target azimuth.

According to the tetrahedral array target orientation estimation method based on differential optimization, the four primitives are respectively set to A, B, C, D, and a tetrahedral array model ABCD is formed;

in the step one, sound pressure time domain signals received by four elements are p in sequence₁(t)、p₂(t)、p₃(t) and p₄(t) for p₁(t)、

p₂(t)、p₃(t) and p₄(t) performing fast Fourier transform to obtain a corresponding frequency domain signal P₁(f)、P₂(f)、P₃(f) And P₄(f)。

According to the tetrahedral array target orientation estimation method based on differential optimization, in the second step, the rectangular coordinate system comprises a rectangular coordinate system xyz established by taking the center O of the tetrahedral array model as an origin, wherein the z axis is along the OD direction, the y axis is parallel to BC, and the x axis meets the right-hand coordinate system.

According to the tetrahedral array target orientation estimation method based on differential optimization, the four non-repetitive preprocessing units comprise a preprocessing unit consisting of three ABC surfaces and a corresponding frequency domain signal is P₁(f)、P₂(f) And P₃(f) The pretreatment comprises:

to P₁(f)、P₂(f) Arithmetically summing to obtain P₁₂(f) To P₁(f) And P₃(f) Arithmetically summing to obtain P₁₃(f) (ii) a To P₁(f) And P₂(f) Calculating an arithmetic difference to obtain V₁₂(f) To P₁(f) And P₃(f) Calculating an arithmetic difference to obtain V₁₃(f)；

To P₁₂(f) And V₁₃(f) Performing conjugate multiplication to obtainAnd takes its real part, which is recorded asTo V₁₂(f) And P₁₃(f) Performing conjugate multiplication to obtainAnd takes its real part, which is recorded asTo P₁₂(f) And P₁₃(f) Performing conjugate multiplication to obtainAnd takes its real part, which is recorded as

To findThe wave number k in the x-axis and y-axis directions is obtained_xAnd k_yLinear equation one of (1);

to findThe wave number k in the x-axis and y-axis directions is obtained_xAnd k_yThe second linear equation of (2);

then, the pretreatment is carried out on a pretreatment unit consisting of three elements of the ABD surface to obtain wave numbers k in the directions of the x axis and the y axis_xAnd k_yAnd the wave number k in the x-axis and z-axis directions_xAnd k_zThe linear equation of (4);

then, the preprocessing unit composed of three primitives of the ACD surface is preprocessed to obtain wave numbers k in the directions of the x axis and the y axis_xAnd k_yAnd the linear equation of five, and the wave numbers k in the x-axis and z-axis directions_xAnd k_zThe linear equation of (a);

then respectively carrying out the pretreatment on a pretreatment unit consisting of three elements of the BCD surface to obtain wave numbers k in the directions of the x axis, the y axis and the z axis_x、k_yAnd k_zSeven and eight linear equations.

According to the tetrahedral array target orientation estimation method based on differential optimization, the matrix A is set as follows:

the matrix x is:

x＝[k_xk_yk_z]^T；

in step three, the eight linear equations are solved by using the least square optimization idea, and the obtained correlation robust estimation includes:

in the formula P₁₄Represents a pair P₁(f)、P₄(f) Arithmetically summing the obtained P₁₄(f)，V₁₄Represents a pair P₁(f)、P₄(f) V obtained by arithmetic difference₁₄(f)，P₂₄Represents a pair P₂(f)、P₄(f) Calculation ofSurgery and P obtained₂₄(f)，P₃₄Represents a pair P₃(f)、P₄(f) Arithmetically summing the obtained P₃₄(f)，V₂₄Represents a pair P₂(f)、P₄(f) V obtained by arithmetic difference₂₄(f)，V₃₄Represents a pair P₃(f)、P₄(f) V obtained by arithmetic difference₃₄(f) (ii) a d represents the distance between any two primitives;

and then based on the least square optimization idea, obtaining:

according to the tetrahedral array target orientation estimation method based on differential optimization, the target azimuth angle theta in the fourth step is as follows:

θ＝atan2(k_y/k_x)；

target pitch angleComprises the following steps:

the invention has the beneficial effects that: the method is suitable for target orientation estimation of underwater mobile platforms such as UUV, glider and the like by adopting any tetrahedral array configuration. The method is based on signal difference between tetrahedral array elements and target parameter optimization estimation, and improves the robustness of tetrahedral array target orientation estimation by using the idea of information redundancy.

The method converts the target orientation estimation problem into a linear equation set solving problem through numerical operation while utilizing the concept of sound intensity (sound pressure element difference), and simultaneously fully multiplexes acoustic information of each surface element of the tetrahedral array (provides redundant information), thereby improving the robustness of the tetrahedral array target orientation estimation by overdetermining the linear equation set through the concept of least square optimization. The method gives full play to the potential information acquisition advantages of the tetrahedral array.

Drawings

FIG. 1 is a schematic diagram of a tetrahedral array model and its coordinate system according to the present invention;

FIG. 2 is a graph comparing a target azimuth obtained by the method of the present invention with a theoretical value of the target azimuth;

fig. 3 is a comparison graph of a target pitch angle obtained by the method of the present invention and a theoretical value of the target pitch angle.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.