Underwater target motion state evaluation method based on distributed sound barrier system

Abstract

The invention belongs to the technical field of underwater acoustic detection. The invention provides an underwater target motion state evaluation method based on a distributed sound barrier system. According to the embodiment of the invention, the two-dimensional coordinate of the target passing through the sound barrier for the first time, the target speed and the navigation angle are used as to-be-estimated parameters, and a parameter estimation problem is converted into a linear equation set solving problem; and substituting the delay inequality of the target crossing the sound barriers into the equation, solving the target motion state estimation, and further calculating the distance between the target and the sound source when the target crosses each sound barrier. Under the lowest standard that the product of the number of the sound sources and the number of the receivers is not smaller than 4, the method can be used for any sound transmission system composed of the multiple sound sources and the receivers, universality is higher, and the state estimation result is accurate and reliable.

Description

Technical Field

[0001] The disclosed embodiments relate to the field of underwater acoustic detection technology, and in particular to a method for evaluating the motion state of an underwater target based on a distributed sound barrier system. Background Art

[0002] Research shows that the distributed active sound transmission system forms a detection sound barrier on the line connecting each sound source and receiver. When the target crosses the sound barrier, the forward sound scattering effect of the target body and the excited source-induced internal waves will cause the received sound field to continuously vary. The time when the target crosses the sound barrier can be extracted using a suitable detection algorithm, but it is not enough to achieve the state estimation of the target speed, heading, etc. The existing methods have many restrictions on the target prior information and system configuration, and face problems such as insufficient estimation accuracy and limited number of sensors in practical applications; some methods assume that the target speed is known and use multiple sound barriers to obtain the target distance estimation result, but the target speed information is difficult to obtain in practical applications; there are also methods that use the time delay difference and geometric relationship of the target crossing the transmission and reception line of the dual-transmitter and dual-receiver system for projection ranging, but it fails when the target crosses the intersection of the sound barrier, and the application scenario is limited to dual-transmitter and dual-receiver.

[0003] Therefore, it is necessary to improve one or more problems existing in the above-mentioned related technical solutions.

[0004] It should be noted that this section is intended to provide background or context for the technical solutions of the present disclosure stated in the claims. The description herein is not admitted to be prior art by virtue of being included in this section. Summary of the invention

[0005] The purpose of the embodiments of the present disclosure is to provide a method for evaluating the motion state of an underwater target based on a distributed sound barrier system, thereby overcoming one or more problems caused by the limitations and defects of related technologies at least to a certain extent.

[0006] According to a first aspect of an embodiment of the present disclosure, a method for evaluating the motion state of an underwater target based on a distributed sound barrier system is provided, the method comprising: Deploy a distributed sound barrier system and establish a distributed sound barrier and target motion model; wherein the distributed sound barrier system includes M sound sources and N receivers, and M×N sound barriers are formed between each sound source and receiver; According to the target parameters of the target to be estimated in the distributed sound barrier and the target motion model, a parameter estimation linear equation group is constructed; The least squares algorithm is used to solve the parameter estimation linear equations to obtain the target parameter estimation results; According to the target parameter estimation results, the speed, navigation angle, and position and distance estimation of the target when crossing each sound barrier are obtained.

[0007] Furthermore, the steps of deploying a distributed sound barrier system and establishing a distributed sound barrier and target motion model include: Number the sound sources and receivers starting from 1 according to their quantity; where M×N≥4; With sound source No. 1 as the origin and the horizontal line between sound source No. 1 and receiver No. 1 as the x-axis, a plane rectangular coordinate system is established; Establish the straight line equations of each sound barrier and the target uniform linear motion equation; According to the straight line equation of each sound barrier and the target uniform straight line motion equation, the distributed sound barrier and target motion models are jointly constructed.

[0008] Furthermore, the linear equation of each sound barrier is expressed as:

[0009] in, is the first coefficient, is the second coefficient, is the third coefficient; and , is the position of each sound source, is the location of each receiver; The expression of the target uniform linear motion equation is:

[0010] in, The target to be estimated at the reference time The location where the first sound barrier is crossed, For the moment The target position to be estimated, is the horizontal velocity of the target to be estimated, is the vertical velocity of the target to be estimated, is the speed of the target to be estimated, is the navigation angle of the target to be estimated; The expression of the distributed sound barrier and target motion model is:

[0011] in, is the time when the target is estimated to pass through each sound barrier.

[0012] Furthermore, the step of constructing a parameter estimation linear equation group according to the target parameters of the target to be estimated in the distributed sound barrier and the target motion model includes: The parameters of the target to be estimated are formed according to the horizontal and vertical coordinates of the position where the target to be estimated crosses the first sound barrier, the target movement speed, the speed of the target to be estimated and the navigation angle of the target to be estimated; Construct a parameter estimation linear equation system based on the target parameters to be estimated.

[0013] Furthermore, the step of solving the parameter estimation linear equations using the least squares algorithm to obtain the target parameter estimation result includes: Use detection algorithms to obtain the moment when the target passes through each sound barrier; The time when the target passes through each sound barrier is substituted into the parameter estimation linear equation group and solved based on the least squares method to obtain the target parameter estimation result.

[0014] Furthermore, the expression of the target parameter estimation result is:

[0015] in, is the coefficient matrix, is the parameter to be estimated, is a constant vector.

[0016] Further, the step of obtaining the speed, navigation angle, and position and distance estimation of the target to be estimated when crossing each sound barrier according to the target parameter estimation result includes: According to the target parameter estimation result, the speed of the target to be estimated and the navigation angle of the target to be estimated are obtained; According to the speed of the target to be estimated and the navigation angle of the target to be estimated, the position and distance estimation when crossing each sound barrier are obtained.

[0017] Furthermore, the expression of the speed of the target to be estimated is:

[0018] The expression of the navigation angle of the target to be estimated is:

[0019] The expression of the position when passing through each sound barrier is:

[0020] The expression for estimating the distance from the origin when crossing each sound barrier is:

[0021] in, is the origin position.

[0022] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects: In the embodiment of the present disclosure, through the above-mentioned underwater target motion state assessment method based on the distributed sound barrier system, on the one hand, the two-dimensional coordinates of the target's first crossing of the sound barrier, the target speed and the navigation angle are used as the parameters to be estimated, and the parameter estimation problem is converted into a linear equation system solution problem; the time delay difference of the target crossing the sound barrier is substituted into the equation to solve the target motion state estimation, and further infer the distance between the target and the sound source when crossing each sound barrier. On the other hand, under the minimum standard that the product of the number of sound sources and receivers is not less than 4, this method can be used for any sound transmission system composed of multiple sound sources and receivers, with stronger versatility and accurate and reliable state estimation results. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0024] Figure 1 A step diagram showing a method for evaluating the motion state of an underwater target based on a distributed sound barrier system in an exemplary embodiment of the present disclosure; Figure 2 A specific flow chart showing a method for evaluating the motion state of an underwater target based on a distributed sound barrier system in an exemplary embodiment of the present disclosure; Figure 3 A schematic diagram showing a target crossing situation 1 in an exemplary embodiment of the present disclosure; Figure 4 A schematic diagram showing a target crossing scenario 2 in an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0025] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the disclosure will be more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0026] In addition, the accompanying drawings are only schematic illustrations of the embodiments of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and their repeated descriptions will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0027] This example embodiment provides a method for evaluating the motion state of an underwater target based on a distributed sound barrier system. Figure 1 As shown in , the underwater target motion state assessment method based on the distributed sound barrier system may include: steps S101 to S104.

[0028] Step S101: deploying a distributed sound barrier system and establishing a distributed sound barrier and target motion model; wherein the distributed sound barrier system includes M sound sources and N receivers, and M×N sound barriers are formed between each sound source and receiver; Step S102: constructing a parameter estimation linear equation group according to the target parameters of the target to be estimated in the distributed sound barrier and the target motion model; Step S103: solving the parameter estimation linear equations using a least squares algorithm to obtain target parameter estimation results; Step S104: According to the target parameter estimation result, the speed, navigation angle, and position and distance estimation of the target to be estimated when crossing each sound barrier are obtained.

[0029] Through the above-mentioned underwater target motion state assessment method based on the distributed sound barrier system, on the one hand, the two-dimensional coordinates of the target's first crossing of the sound barrier, the target speed and the navigation angle are used as the parameters to be estimated, and the parameter estimation problem is transformed into a linear equation system solution problem; the time delay difference of the target crossing the sound barrier is substituted into the equation to solve the target motion state estimation, and further infer the distance between the target and the sound source when crossing each sound barrier. On the other hand, under the minimum standard that the product of the number of sound sources and receivers is not less than 4, this method can be used for any sound transmission system composed of multiple sound sources and receivers, with stronger versatility and accurate and reliable state estimation results.

[0030] Next, we will refer to Figures 1 to 4 The various steps of the above-mentioned underwater target motion state assessment method based on the distributed sound barrier system in this example implementation are described in more detail.

[0031] In step S101, Figure 2 As shown in FIG. 1 , a specific flow chart of the underwater target motion state assessment method based on a distributed sound barrier system is shown. A distributed sound barrier system is deployed, and a distributed sound barrier and target motion model is established; wherein the distributed sound barrier system includes M sound sources and N receivers, and M×N sound barriers are formed between each sound source and receiver.

[0032] Specifically, the system consists of M sound sources and N receivers with separate transmitters and receivers. Each sound source consists of P transducers (P≥1), and each receiver consists of a hydrophone array with Q elements (Q≥1). The product of the number of sound sources and receivers is not less than 4 (M×N≥4), and the sound sources and receivers are numbered starting from 1. Each sound source radiates detection pulses with non-overlapping frequency bands (common signal forms such as linear frequency modulation and hyperbolic frequency modulation are acceptable). Each receiver continuously collects the transmission signals of each sound source, forming M×N sound barriers between each sound source and receiver.

[0033] Using the above system configuration, the mathematical equations of the distributed sound barrier and target motion model are established: Step 1: Take sound source 1 as the origin and the horizontal line between sound source 1 and receiver 1 as the positive x-axis to establish a plane rectangular coordinate system. Indicates that Characterize the sound source, subscript Respectively represent the horizontal and vertical coordinates, m is the sound source number ranging from 1 to M; the position of each receiver node is represented by Indicates that represents the sound source, n is the receiver number ranging from 1 to N. The sound barrier between each sound source and the receiver It can be represented as a straight line, whose equation is:

[0034] in Characterizes the sound barrier number between the mth sound source and the nth receiver, the equation coefficient is:

[0035] Step 2: When the target is sailing in a straight line at a constant speed, its motion equation is:

[0036] in For the target at the reference time The location where the first sound barrier is crossed, and For the moment The target location, and are the horizontal and vertical velocities of the target, respectively. is the target speed, is the target heading (defined as the target navigation direction vector and The model can also be used for non-uniform linear motion targets, but there will be errors.

[0037] Target in time Crossing the sound barrier , the target track intersects with the sound barrier, and the sound barrier equation and the target motion equation are combined to get:

[0038] In step S102 and step S103, if Figure 2 As shown, according to the target parameters of the target to be estimated in the distributed sound barrier and the target motion model, a parameter estimation linear equation group is constructed; the parameter estimation linear equation group is solved using the least squares algorithm to obtain the target parameter estimation result.

[0039] Specifically, the target parameter to be estimated is defined as the variable to be measured, a linear equation system for parameter estimation is constructed, and the system is solved based on the least squares algorithm.

[0040] Step 1: The target parameters to be estimated include , , , There are 4 parameters in total, which are the horizontal and vertical coordinates of the position where the target crosses the first sound barrier, the target movement speed, and the target navigation angle. Therefore, the target parameter estimation problem is transformed into a linear equation system solution problem. The above problems are organized as follows:

[0041] in is the coefficient matrix, is the parameter to be estimated, is a constant vector, and the three are:

[0042] in for The coefficient sub-matrix of for The coefficient sub-vector of The geometric coefficients of the sound barrier equation composed of the sound source and each receiver are composed of: .

[0043] Step 2: Obtain the moment when the target crosses each sound barrier based on a suitable detection algorithm , substituted into the linear equations and solved based on the least squares method, the target parameter estimation results are as follows:

[0044] In step S104, Figure 2 As shown, according to the target parameter estimation results, the speed, navigation angle, and position and distance estimation of the target to be estimated when crossing each sound barrier are obtained.

[0045] Specifically, the target speed and navigation angle are calculated based on the parameter estimation results. The target speed is , the navigation angle is Therefore, the position of the target crossing the other three sound barriers can be estimated as:

[0046] Based on the target crossing position, the distance to the origin is estimated as:

[0047] In a specific embodiment, referring to Figure 3 and Figure 4 The following is an application example. The simulation configures a dual-transmitter and dual-receiver underwater target detection system, including two sound sources and two receivers. Each sound source and receiver consists of a transducer. With sound source 1 as the origin, the line connecting sound source 1 and receiver 1 is Axis positive direction, establish a plane rectangular coordinate system, the unit is meter (if not marked, the subsequent coordinate unit is meter). The coordinates of sound sources 1 and 2 are and , the coordinates of receivers 1 and 2 are and The sound source transmits a linear frequency modulation pulse with a center frequency of 50 kHz, a bandwidth of 5kHz, and a pulse width of 0.2 s at a period of 0.5 s. The receiver continuously collects and processes high-frequency detection pulses from the sound source, forming a total of 4 sound barriers between each transmission and reception. The initial position of the target is set at ,by The speed (about 7.72 m / s) along The receiver moves in a straight line at a uniform speed in the same direction and passes through four sound barriers in sequence. Each time it passes through a sound barrier, the receiver outputs a target crossing time through the built-in detection algorithm. The coefficient matrix is ​​solved using the system node position and the four target crossing times. , the target position estimation after crossing barrier 1 and the target speed and Directional projection is performed, and the intersection of the target and the other three sound barriers is further obtained.

[0048] When the goal is When the heading angle passes through the detection area at a constant speed, the detection nodes, sound barriers and target tracks are as follows: Figure 3 As shown, the actual speed and angle of the target are marked on Figure 4 In the upper right corner, below it are the detected target crossing the sound barrier, target state estimation, and crossing position estimation results. The sound barrier durations are 7s, 11.5s, 22s, and 27s, respectively. Substituting these durations into the equations, the target speed and angle estimates are 7.87m / s and 72.39°, respectively. and Characterizes the relative error of velocity and heading angle estimation, where and are the estimated and true value of the sailing speed, respectively. and They are the estimated and true values ​​of the navigation angle, with errors of 1.9% and 6.4% respectively.

[0049] When the target passes through the detection area at a constant speed at a heading angle of 88°, the detection nodes, sound barriers and target tracks are as follows: Figure 2 As shown, the time for the target to cross the four sound barriers is 6.5s, 10.5s, 22s and 26s respectively. Substituting into the linear equations, the target speed and angle estimation results are 7.87m / s and 72.39° respectively, with errors of 0.4% and 2.2% respectively.

[0050] The present application has achieved obvious implementation effects in typical embodiments. The target motion state estimation method based on distributed sound barriers has little restriction on system layout and sensor configuration, has good versatility and robustness, can be used for target early warning and defense in important areas such as ports and important roads, and has broad application prospects.

[0051] Through the above-mentioned underwater target motion state assessment method based on distributed sound barrier system, based on a distributed sound barrier system composed of no less than 4 transceiver nodes, after obtaining the time when the target crosses each sound barrier by using appropriate detection methods, the target crossing between the transmitter and the receiver can achieve accurate estimation of the motion speed, navigation angle and distance. This method establishes a linear equation group based on the detection node position and the target motion model, and uses the two-dimensional coordinates of the target crossing the sound barrier for the first time, the target speed and the navigation angle as the parameters to be estimated, and transforms the parameter estimation problem into a linear equation group solution problem; substitutes the time delay difference of the target crossing the sound barrier into the equation, solves the target motion state estimation, and further infers the distance between the target and the sound source when crossing each sound barrier. Under the minimum standard that the product of the number of sound sources and receivers is not less than 4, the method can be used for sound transmission systems composed of any number of sound sources and receivers, with stronger versatility and accurate and reliable state estimation results.

[0052] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0053] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A method for evaluating the motion state of an underwater target based on a distributed sound barrier system, characterized in that: The method includes: Deploy a distributed sound barrier system and establish a distributed sound barrier and target motion model; wherein the distributed sound barrier system includes M sound sources and N receivers, and M×N sound barriers are formed between each sound source and receiver; According to the target parameters of the target to be estimated in the distributed sound barrier and the target motion model, a parameter estimation linear equation group is constructed; The least squares algorithm is used to solve the parameter estimation linear equations to obtain the target parameter estimation results; According to the target parameter estimation results, the speed, navigation angle, and position and distance estimation of the target when crossing each sound barrier are obtained.

2. According to claim 1, the method for evaluating the motion state of underwater targets based on a distributed sound barrier system is characterized in that: The steps of deploying a distributed sound barrier system and establishing a distributed sound barrier and target motion model include: Number the sound sources and receivers starting from 1 according to their quantity; where M×N≥4; With sound source No. 1 as the origin and the horizontal line between sound source No. 1 and receiver No. 1 as the x-axis, a plane rectangular coordinate system is established; Establish the straight line equations of each sound barrier and the target uniform linear motion equation; According to the straight line equation of each sound barrier and the target uniform straight line motion equation, the distributed sound barrier and target motion models are jointly constructed.

3. According to claim 2, the method for evaluating the motion state of underwater targets based on a distributed sound barrier system is characterized in that: The expression of the straight line equation of each sound barrier is: in, is the first coefficient, is the second coefficient, is the third coefficient; and , is the position of each sound source, is the location of each receiver; The expression of the target uniform linear motion equation is: in, The target to be estimated at the reference time The location where the first sound barrier is crossed, For the moment The target position to be estimated, is the horizontal velocity of the target to be estimated, is the vertical velocity of the target to be estimated, is the speed of the target to be estimated, is the navigation angle of the target to be estimated; The expression of the distributed sound barrier and target motion model is: in, is the time when the target is estimated to pass through each sound barrier.

4. According to claim 3, the method for evaluating the motion state of underwater targets based on a distributed sound barrier system is characterized in that: The step of constructing a parameter estimation linear equation group according to the target parameters of the target to be estimated in the distributed sound barrier and the target motion model includes: The parameters of the target to be estimated are formed according to the horizontal and vertical coordinates of the position where the target to be estimated crosses the first sound barrier, the target movement speed, the speed of the target to be estimated and the navigation angle of the target to be estimated; Construct a parameter estimation linear equation system based on the target parameters to be estimated.

5. According to claim 4, the method for evaluating the motion state of underwater targets based on a distributed sound barrier system is characterized in that: The steps of solving the parameter estimation linear equations using the least squares algorithm to obtain the target parameter estimation results include: Use detection algorithms to obtain the moment when the target passes through each sound barrier; The time when the target passes through each sound barrier is substituted into the parameter estimation linear equation group and solved based on the least squares method to obtain the target parameter estimation result.

6. The underwater target motion state assessment method based on the distributed sound barrier system according to claim 5 is characterized in that: The expression of the target parameter estimation result is: in, is the coefficient matrix, is the parameter to be estimated, is a constant vector.

7. The underwater target motion state assessment method based on a distributed sound barrier system according to claim 6 is characterized in that: The step of obtaining the speed, navigation angle, position and distance of the target to be estimated when crossing each sound barrier according to the target parameter estimation result includes: According to the target parameter estimation result, the speed of the target to be estimated and the navigation angle of the target to be estimated are obtained; According to the speed of the target to be estimated and the navigation angle of the target to be estimated, the position and distance estimation when crossing each sound barrier are obtained.

8. The underwater target motion state assessment method based on a distributed sound barrier system according to claim 7 is characterized in that: The expression of the target speed to be estimated is: The expression of the navigation angle of the target to be estimated is: The expression of the position when passing through each sound barrier is: The expression for estimating the distance from the origin when crossing each sound barrier is: in, is the origin position.

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