Ultra-short baseline positioning method and system based on sound propagation path similarity

Abstract

The invention relates to the technical field of ultra-short baseline positioning, in particular to an ultra-short baseline positioning method and system based on sound propagation path similarity, and the method comprises the steps: constructing a spatial position relation between a hydrophone and a sound source target according to a position vector of the hydrophone in a USBL system in a carrier coordinate system; taking the sound signal propagation delay distance as an observation value, and establishing an observation error function model according to the spatial position relationship, wherein the observation error function model takes the effective sound velocity, the sound source position vector and the sound source position vector modular square as undetermined parameters; and carrying out iterative approximation on the position error function model by utilizing a least square criterion and through the virtual observation value, and obtaining the optimal effective sound velocity, sound source position vector and modular square thereof in the function model through iterative approximation. According to the method, under the condition that no extra information assistance is needed, only the approximate initial value of the effective sound velocity is provided, the influence of sound ray bending on ultra-short base line positioning can be eliminated, and the method is suitable for being applied to an ultra-short base line positioning / short base line positioning system.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-short baseline positioning, and in particular to an ultra-short baseline positioning method and system based on similarity of sound propagation paths. Background Art

[0002] Ultra-short baseline positioning technology plays an extremely important role in underwater navigation and positioning, and positioning accuracy is a key indicator for evaluating its performance. One of the key factors affecting the positioning accuracy of ultra-short baselines is the sound line bending phenomenon caused by the change of sound velocity along the vertical direction. Existing methods mainly improve the accuracy of ultra-short baseline direction and distance measurement from the perspective of signal processing, which cannot eliminate or weaken the impact of sound line bending on positioning results. Based on the use of advanced signal processing methods, existing methods also correct the impact of sound line bending on distance measurement through sound line tracking. This method can weaken the impact of sound line bending, but because it does not take into account the impact of sound line bending on direction measurement, it still cannot completely eliminate the impact of sound line bending on ultra-short baseline positioning. In addition, sound line tracking requires accurate beam initial incidence angle and sound velocity profile data, which puts forward the requirement of additional auxiliary information for the ultra-short baseline positioning system, and cannot meet the requirements of ultra-short baseline system to be light and flexible. Summary of the invention

[0003] To this end, the present invention provides an ultra-short baseline positioning method and system based on the similarity of sound propagation paths, which solves the problem of requiring accurate beam initial incidence angle and sound velocity profile data for additional auxiliary information in existing ultra-short baseline positioning.

[0004] According to the design scheme provided by the present invention, on the one hand, an ultra-short baseline positioning method based on the similarity of sound propagation paths is provided, comprising:

[0005] The spatial position relationship between the hydrophone and the sound source target is established according to the position vector of the hydrophone in the carrier coordinate system in the USBL system, the propagation delay distance of the acoustic signal is used as the observation value and an observation error function model is established according to the spatial position relationship. The observation error function model uses the effective sound speed, the sound source position vector and the square of the sound source position vector as unknown parameters.

[0006] The position error function model is iteratively approximated by using the least squares criterion and virtual observation values, and the optimal effective sound speed, sound source position vector and its modulus square in the function model are obtained through iterative approximation.

[0007] As an ultra-short baseline positioning method based on the similarity of sound propagation paths of the present invention, further, a spatial position relationship between a hydrophone and a sound source target is constructed, comprising:

[0008] The distance representing the propagation delay of the acoustic signal is expressed based on the time when the acoustic signal is transmitted, the time when the hydrophone receives the acoustic signal, and the effective speed of sound;

[0009] The spatial position relationship between the hydrophone and the sound source is established by utilizing the distance of the acoustic signal propagation delay and based on the position vectors of the hydrophone and the sound source in the carrier coordinate system.

[0010] As the ultra-short baseline positioning method based on the similarity of the sound propagation path of the present invention, further, the spatial position relationship is expressed as: Among them, ρ i is the distance of the acoustic signal propagation delay, and ρ i =c eff (t i -t0), c eff is the effective sound speed, t0 is the time when the sound signal is emitted, t i is the time when hydrophone i receives the acoustic signal, p i and p are the position vectors of the hydrophone and the sound source in the carrier coordinate system, respectively.

[0011] As the ultra-short baseline positioning method based on the similarity of the sound propagation path of the present invention, further, an observation error function model is established according to the spatial position relationship, including:

[0012] The average sound velocity of the working water area is taken as the initial value of the effective sound velocity. Based on the spatial position relationship and using the known position vector of the hydrophone in the carrier coordinate system, an observation error function model is constructed with the square of the propagation delay distance of the acoustic signal received by the hydrophone as the residual.

[0013] As the ultra-short baseline positioning method based on the similarity of the sound propagation path of the present invention, further, the observation error function model is expressed as: Among them, v i is the residual error of the square of the propagation delay distance of the acoustic signal received by hydrophone i, c eff is the effective sound speed, t0 is the time when the sound signal is emitted, t i is the moment when hydrophone i receives the acoustic signal, P is the position vector of the sound source, and p i is the known position vector of hydrophone i in the carrier coordinate system.

[0014] As an ultra-short baseline positioning method based on the similarity of the acoustic propagation path of the present invention, further, the least squares criterion is used and the position error function model is iteratively approximated by virtual observation values, including:

[0015] The coefficient matrix and free terms of the least square error equation are constructed using the known position vector of the hydrophone in the carrier coordinate system and the square of the acoustic signal propagation delay distance, and the least square estimated parameters are represented by the sound source position vector.

[0016] The effective sound velocity is used to augment the estimated parameters to obtain augmented parameter vectors, and the augmented parameter vectors are used to transform the observation error function model into a nonlinear equation, and the transformed nonlinear equation is linearized, wherein the free terms in the linearized observation error equation are expressed based on parameter approximations;

[0017] According to the constraints between parameters, the linearized observation error equation is expressed as a total observation error equation with infinite weights and a weight matrix is ​​obtained, and the parameter estimation is calculated based on the total observation error equation and the weight matrix;

[0018] The parameter estimates are used to update the parameter approximation, and the parameter estimates are repeatedly calculated based on the total observation error equation and the weight matrix until the parameter estimates reach the preset stability condition.

[0019] As the ultra-short baseline positioning method based on the similarity of the acoustic propagation path of the present invention, further, the total observation error equation is expressed as: The weight matrix is ​​expressed as: The parameter estimation calculation process is expressed as: in, is the coefficient matrix after linearization, is the vector parameter represented by the least squares solution, is the free term after linearization, l x is the parameter formed by the square of the least squares solution, I is a unit vector, P x is a pre-set real number, represents the least squares estimate of the augmented parameter vector after adding constraints between parameters, X 0 is an approximate value of the parameter.

[0020] On the other hand, the present invention also provides an ultra-short baseline positioning system based on the similarity of acoustic propagation paths, comprising: a model building module and a model approximation module, wherein:

[0021] A model building module is used to build a spatial position relationship between the hydrophone and the sound source target according to the position vector of the hydrophone in the carrier coordinate system in the USBL system, take the acoustic signal propagation delay distance as the observation value and establish an observation error function model according to the spatial position relationship, wherein the observation error function model uses the effective sound speed, the sound source position vector and the square of the sound source position vector as undetermined parameters;

[0022] The model approximation module is used to iteratively approximate the position error function model using the least squares criterion and virtual observation values, and obtain the optimal effective sound speed, sound source position vector and its modulus square in the function model through iterative approximation.

[0023] Beneficial effects of the present invention:

[0024] The present invention establishes an error equation based on the spatial position relationship between a hydrophone and a sound source and with the help of an effective sound speed to construct an observation error function model, and simultaneously calculates the position vector of the sound source and the square of its modulus according to the least squares principle; the parameter vector to be estimated is augmented, and a virtual observation value method is used to consider the functional relationship between the sound source position vector and the square of its modulus; for a new nonlinear error equation group, a parameter estimation method is used to calculate the nonlinear least squares method, which is suitable for an ultra-short baseline using a multi-element receiving array (no less than 4 hydrophones), and the original observation value is the propagation time of the sound signal collected by each hydrophone; without any additional information assistance, only an approximate initial value of the effective sound speed is provided, so that the influence of the sound line bending on the ultra-short baseline positioning can be eliminated, and the present invention is not only suitable for an ultra-short baseline positioning system, but also can be used for a short baseline positioning system, and the calculation process is simple and easy to program and develop, and has a good application prospect in the field of ultra-short baseline positioning. Description of the drawings:

[0025] Figure 1 This is a schematic diagram of the ultra-short baseline positioning process based on the similarity of the sound propagation path in the embodiment;

[0026] Figure 2 Schematic diagram of the spatial position relationship between the hydrophone and the sound source in the embodiment. Specific implementation method:

[0027] In order to make the purpose, technical solutions and advantages of the present invention clearer and more understandable, the present invention is further described in detail below in conjunction with the accompanying drawings and technical solutions.

[0028] Since the distance between the ultra-short baseline hydrophones is very small, the propagation paths of the sound waves received by the hydrophones in the water are similar. Figure 1 As shown, an ultra-short baseline positioning method based on the similarity of sound propagation paths is provided, comprising:

[0029] S101. Construct the spatial position relationship between the hydrophone and the sound source target based on the position vector of the hydrophone in the carrier coordinate system in the USBL system, take the acoustic signal propagation delay distance as the observation value and establish an observation error function model based on the spatial position relationship. The observation error function model uses the effective sound speed, the sound source position vector and the square of the sound source position vector modulus as unknown parameters.

[0030] Specifically, the spatial position relationship between the hydrophone and the sound source target can be designed to include:

[0031] The distance representing the propagation delay of the acoustic signal is expressed based on the time when the acoustic signal is transmitted, the time when the hydrophone receives the acoustic signal, and the effective speed of sound;

[0032] The spatial position relationship between the hydrophone and the sound source is established by utilizing the distance of the acoustic signal propagation delay and based on the position vectors of the hydrophone and the sound source in the carrier coordinate system.

[0033] like Figure 2 As shown, let the position vector of hydrophone i in the carrier coordinate system be p i , the position vector of the sound source is p, then the spatial geometric distance between the hydrophone and the sound source is ||pp i || (||·|| represents modular operation), establish the following mathematical relationship:

[0034]

[0035] In the formula, ρ i =c eff (t i -t0) is the distance calculated by the propagation delay of the acoustic signal, c eff is the effective sound speed (defined as the ratio of the Euclidean distance between the sound source and the receiving point to the propagation time of the intrinsic sound line), t0 is the time when the sound signal is emitted, and t i is the moment when hydrophone i receives the acoustic signal.

[0036] The average sound velocity of the working water area is taken as the initial value of the effective sound velocity. Based on the spatial position relationship and using the known position vector of the hydrophone in the carrier coordinate system, an observation error function model is constructed with the square of the propagation delay distance of the acoustic signal received by the hydrophone as the residual.

[0037] Taking the average sound velocity in the working water area as the initial value of the effective sound velocity, the error equation is established:

[0038]

[0039] S102, using the least squares criterion and virtual observation values ​​to iteratively approximate the position error function model, and obtaining the optimal effective sound speed, sound source position vector and its square modulus in the function model through iterative approximation.

[0040] Taking the effective sound velocity, sound source position vector and the square of its modulus as unknown parameters and the acoustic signal propagation time as the original observation value, a nonlinear function model is established according to the spatial position relationship between the hydrophone and the sound source. The nonlinear least squares method is used in combination with the virtual observation method to calculate the numerical optimal solution of the parameter vector through iterative approximation.

[0041] Specifically, the least squares criterion is used and the position error function model is iteratively approximated by virtual observation values, which may include:

[0042] The coefficient matrix and free terms of the least square error equation are constructed using the known position vector of the hydrophone in the carrier coordinate system and the square of the acoustic signal propagation delay distance, and the least square estimated parameters are represented by the sound source position vector.

[0043] The effective sound velocity is used to augment the estimated parameters to obtain augmented parameter vectors, and the augmented parameter vectors are used to transform the observation error function model into a nonlinear equation, and the transformed nonlinear equation is linearized, wherein the free terms in the linearized observation error equation are expressed based on parameter approximations;

[0044] According to the constraints between parameters, the linearized observation error equation is expressed as a total observation error equation with infinite weights and a weight matrix is ​​obtained, and the parameter estimation is calculated based on the total observation error equation and the weight matrix;

[0045] The parameter estimates are used to update the parameter approximation, and the parameter estimates are repeatedly calculated based on the total observation error equation and the weight matrix until the parameter estimates reach the preset stability condition.

[0046] Let the coefficient matrix Free Item Parameters to be estimated is a 4×1 column vector, and its least squares solution is

[0047]

[0048] Augmented parameter vector X = [X T c eff ] T , then the error equation becomes a nonlinear equation, which can be linearized into

[0049]

[0050] In the formula, a=[a1 a2…a n ] T , where a i =2c eff (t i -t0) 2 ; X 0 Indicates the approximate value of the parameter, which is taken as the last adjustment value, and the initial value is taken as

[0051] According to the functional relationship between parameters p T p=||p|| 2 , establish a mathematical expression for the constraint violation value (also called the residual):

[0052]

[0053] Linearizing formula (5), we get:

[0054]

[0055] Considering the above equation as an error equation with infinite weight, the total error equation group and weight matrix are:

[0056]

[0057]

[0058] In the formula, P x is a relatively large real number set in advance. It is recommended that P x ≥10 5 .

[0059] Calculate the new parameter estimates as

[0060]

[0061] In the formula, represents the least squares estimate of the augmented parameters and the constraints between them.

[0062] Update the approximate value of the parameter (i.e. ), and repeat the steps of calculating new parameter estimates based on the total error equations and weight matrix until the parameter estimates tend to be stable, that is, satisfying:

[0063]

[0064] Where ε is a very small positive real number set artificially, and it is recommended to be less than 0.001m.

[0065] Furthermore, based on the above method, an embodiment of the present invention also provides an ultra-short baseline positioning system based on the similarity of acoustic propagation paths, comprising: a model building module and a model approximation module, wherein:

[0066] A model building module is used to build a spatial position relationship between the hydrophone and the sound source target according to the position vector of the hydrophone in the carrier coordinate system in the USBL system, take the acoustic signal propagation delay distance as the observation value and establish an observation error function model according to the spatial position relationship, wherein the observation error function model uses the effective sound speed, the sound source position vector and the square of the sound source position vector as undetermined parameters;

[0067] The model approximation module is used to iteratively approximate the position error function model using the least squares criterion and virtual observation values, and obtain the optimal effective sound speed, sound source position vector and its modulus square in the function model through iterative approximation.

[0068] Unless otherwise specifically stated, the relative steps, numerical expressions and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present invention.

[0069] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0070] The units and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. A person of ordinary skill in the art may use different methods to implement the described functions for each specific application, but such implementation is not considered to be beyond the scope of the present invention.

[0071] Those skilled in the art will appreciate that all or part of the steps in the above method can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, such as a read-only memory, a disk or an optical disk. Optionally, all or part of the steps in the above embodiment can also be implemented using one or more integrated circuits, and accordingly, each module / unit in the above embodiment can be implemented in the form of hardware or in the form of software function modules. The present invention is not limited to any specific form of combination of hardware and software.

[0072] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An ultra-short baseline positioning method based on the similarity of acoustic propagation paths, characterized in that: Include: The spatial position relationship between the hydrophone and the sound source target is established according to the position vector of the hydrophone in the carrier coordinate system in the USBL system, the propagation delay distance of the acoustic signal is used as the observation value and an observation error function model is established according to the spatial position relationship. The observation error function model uses the effective sound speed, the sound source position vector and the square of the sound source position vector as unknown parameters. The position error function model is iteratively approximated by using the least squares criterion and virtual observation values, and the optimal effective sound speed, sound source position vector and its modulus square in the function model are obtained through iterative approximation.

2. The ultra-short baseline positioning method based on acoustic propagation path similarity according to claim 1 is characterized in that: Construct the spatial position relationship between the hydrophone and the sound source target, including: The distance representing the propagation delay of the acoustic signal is expressed based on the time when the acoustic signal is transmitted, the time when the hydrophone receives the acoustic signal, and the effective speed of sound; The spatial position relationship between the hydrophone and the sound source is established by utilizing the distance of the acoustic signal propagation delay and based on the position vectors of the hydrophone and the sound source in the carrier coordinate system.

3. The ultra-short baseline positioning method based on acoustic propagation path similarity according to claim 1 or 2, characterized in that: The spatial position relationship is expressed as: Among them, ρ i is the distance of the acoustic signal propagation delay, and ρ i =c eff (t i -t0), c eff is the effective sound speed, t0 is the time when the sound signal is emitted, t i is the time when hydrophone i receives the acoustic signal, p i and p are the position vectors of the hydrophone and the sound source in the carrier coordinate system, respectively.

4. The ultra-short baseline positioning method based on acoustic propagation path similarity according to claim 1 is characterized in that: The observation error function model is established based on the spatial position relationship, including: The average sound velocity of the working water area is taken as the initial value of the effective sound velocity. Based on the spatial position relationship and using the known position vector of the hydrophone in the carrier coordinate system, an observation error function model is constructed with the square of the propagation delay distance of the acoustic signal received by the hydrophone as the residual.

5. The ultra-short baseline positioning method based on acoustic propagation path similarity according to claim 1 or 4, characterized in that: The observation error function model is expressed as: Among them, v i is the residual error of the square of the propagation delay distance of the acoustic signal received by hydrophone i, c eff is the effective sound speed, t0 is the time when the sound signal is emitted, t i is the moment when hydrophone i receives the acoustic signal, P is the position vector of the sound source, and p i is the known position vector of hydrophone i in the carrier coordinate system.

6. The ultra-short baseline positioning method based on acoustic propagation path similarity according to claim 1, characterized in that: The position error function model is iteratively approximated using the least squares criterion and virtual observation values, including: The coefficient matrix and free terms of the least square error equation are constructed using the known position vector of the hydrophone in the carrier coordinate system and the square of the acoustic signal propagation delay distance, and the least square estimated parameters are represented by the sound source position vector. The effective sound velocity is used to augment the estimated parameters to obtain augmented parameter vectors, and the augmented parameter vectors are used to transform the observation error function model into a nonlinear equation, and the transformed nonlinear equation is linearized, wherein the free terms in the linearized observation error equation are expressed based on parameter approximations; According to the constraints between parameters, the linearized observation error equation is expressed as a total observation error equation with infinite weights and a weight matrix is ​​obtained, and the parameter estimation is calculated based on the total observation error equation and the weight matrix; The parameter estimates are used to update the parameter approximation, and the parameter estimates are repeatedly calculated based on the total observation error equation and the weight matrix until the parameter estimates reach the preset stability condition.

7. The ultra-short baseline positioning method based on acoustic propagation path similarity according to claim 6 is characterized in that: The total observation error equation is expressed as: The weight matrix is ​​expressed as: The parameter estimation calculation process is expressed as: in, is the coefficient matrix after linearization, is the vector parameter represented by the least squares solution, is the free term after linearization, l x is the parameter formed by the square of the least squares solution, I is a unit vector, P x is a pre-set real number, represents the least squares estimate of the augmented parameter vector after adding constraints between parameters, X 0 is an approximate value of the parameter.

8. An ultra-short baseline positioning system based on similarity of acoustic propagation paths, characterized in that: Contains: model building module and model approximation module, among which, A model building module is used to build a spatial position relationship between the hydrophone and the sound source target according to the position vector of the hydrophone in the carrier coordinate system in the USBL system, take the acoustic signal propagation delay distance as the observation value and establish an observation error function model according to the spatial position relationship, wherein the observation error function model uses the effective sound speed, the sound source position vector and the square of the sound source position vector as undetermined parameters; The model approximation module is used to iteratively approximate the position error function model using the least squares criterion and virtual observation values, and obtain the optimal effective sound speed, sound source position vector and its modulus square in the function model through iterative approximation.

9. An electronic device, characterized in that: include: at least one processor, and a memory coupled to the at least one processor; The memory stores a computer program, and the computer program can be executed by the at least one processor to implement the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed, the method according to any one of claims 1 to 7 can be implemented.

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