Underwater passive backscatter node positioning method, system and apparatus

Abstract

This invention provides a method, system, and apparatus for locating underwater passive backscattering nodes, relating to the field of underwater acoustic positioning technology. The method includes: when an underwater mobile vehicle moves along a preset direction from a first position to a second position, acquiring a first received signal corresponding to the first position and a second received signal corresponding to the second position; wherein the first received signal includes a first transmitted signal from the underwater mobile vehicle at the first position and a first reflected signal obtained by reflecting the first transmitted signal through the underwater passive backscattering node; the second received signal includes a second transmitted signal from the underwater mobile vehicle at the second position and a second reflected signal obtained by reflecting the second transmitted signal through the underwater passive backscattering node; and based on the first position, the second position, the first received signal, and the second received signal, determining the position of the underwater passive backscattering node. This invention can determine the position of the underwater passive backscattering node without time synchronization and communication.

Description

Technical Field

[0001] This invention relates to the field of underwater acoustic positioning technology, and in particular to an underwater passive backscattering node positioning method, system and device. Background Technology

[0002] The underwater acoustic backscattering system generally consists of three parts: the first part is the sound source, which serves as the sound signal transmitting device; the second part is the receiver, which uses a hydrophone as the signal receiving device; and the third part is the passive backscattering node.

[0003] In underwater acoustic backscattering systems, it is necessary to locate underwater passive backscattering nodes. Currently, the location of the device to be located typically employs a time-of-flight (TOF) method. This involves multiple receivers receiving signals emitted by the device, recording the time of signal reception, and then calculating the device's location. This method requires the device to be continuously operational. For underwater passive backscattering nodes, wake-up is required during operation; that is, sound waves must be emitted to the node to power it, enabling the internal microcontroller to perform reflection-modulated communication tasks.

[0004] In other words, the underwater passive backscattering node cannot be continuously in working state and needs to be woken up at irregular intervals, which makes time synchronization and communication impossible. Therefore, the above-mentioned time-of-flight-based positioning method cannot achieve the positioning of the underwater passive backscattering node. Summary of the Invention

[0005] This invention provides a method, system, and apparatus for locating underwater passive backscattering nodes, which solves the problem in the prior art that requires the underwater passive backscattering nodes to be woken up at irregular intervals, making time synchronization and communication impossible. This invention enables the location of underwater passive backscattering nodes without the need for time synchronization and communication.

[0006] This invention provides a method for locating underwater passive backscattering nodes, comprising:

[0007] When an underwater mobile carrier moves from a first position to a second position along a preset direction, a first received signal corresponding to the first position and a second received signal corresponding to the second position are acquired; wherein, the first received signal includes a first transmitted signal of the underwater mobile carrier at the first position and a first reflected signal obtained by reflecting the first transmitted signal through an underwater passive backscattering node, and the second received signal includes a second transmitted signal of the underwater mobile carrier at the second position and a second reflected signal obtained by reflecting the second transmitted signal through an underwater passive backscattering node;

[0008] The location of the underwater passive backscattering node is determined based on the first location, the second location, the first received signal, and the second received signal.

[0009] According to a method for locating an underwater passive backscattering node provided by the present invention, determining the location of the underwater passive backscattering node based on a first location, a second location, a first received signal, and a second received signal includes:

[0010] Adaptive filtering is performed on the first received signal and the second received signal respectively to determine the first reflected signal from the first received signal and the second reflected signal from the second received signal.

[0011] The location of the underwater passive backscattering node is determined based on the first location, the second location, the first reflection signal, and the second reflection signal.

[0012] According to the present invention, a method for locating an underwater passive backscattering node, wherein determining the location of the underwater passive backscattering node based on a first location, a second location, a first reflection signal, and a second reflection signal includes:

[0013] The first signal arrival direction of the first reflected signal and the second signal arrival direction of the second reflected signal are determined respectively.

[0014] The location of the underwater passive backscattering node is determined based on the first location, the second location, the first signal arrival direction, and the second signal arrival direction.

[0015] According to the present invention, a method for locating an underwater passive backscattering node, wherein determining the location of the underwater passive backscattering node based on a first location, a second location, a first signal arrival direction, and a second signal arrival direction includes:

[0016] Based on the first position, the direction of arrival of the first signal, and the preset direction, a first positioning ray is determined;

[0017] Based on the second position, the direction of arrival of the second signal, and the preset direction, a second positioning ray is determined;

[0018] The location of the underwater passive backscattering node is determined based on the first positioning ray and the second positioning ray.

[0019] According to the present invention, an underwater passive backscattering node localization method is provided, the method further comprising:

[0020] When the underwater mobile carrier is in the first position, a positioning combination signal is sent to the underwater passive backscattering node;

[0021] If the similarity value between the received reflected signal and the positioning combination signal is greater than or equal to a preset similarity threshold, the distance between the underwater mobile carrier and the underwater passive backscattering node is determined based on the transmission time of the positioning combination signal and the reception time of the reflected signal.

[0022] Determining the location of the underwater passive backscattering node based on the first positioning ray and the second positioning ray includes:

[0023] The intersection point between the first positioning ray and the second positioning ray is determined as the first positioning position;

[0024] The second positioning position is determined based on the first positioning ray and the distance between the underwater mobile carrier and the underwater passive backscattering node.

[0025] Based on the first positioning location and the second positioning location, the location of the underwater passive backscattering node is determined.

[0026] According to the present invention, an underwater passive backscattering node localization method includes performing adaptive filtering on the first received signal and the second received signal respectively, determining a first reflected signal from the first received signal, and determining a second reflected signal from the second received signal, comprising:

[0027] For each of the first received signal and the second received signal, the following operations are performed:

[0028] The received signal is adaptively filtered based on the steepest descent method to determine the reflected signal from the received signal.

[0029] According to the present invention, an underwater passive backscattering node localization method is provided, the method further comprising:

[0030] Determine the preset movement distance of the underwater mobile carrier;

[0031] The second position is determined based on the preset direction, the first position, and the preset moving distance.

[0032] This invention also provides an underwater passive backscattering node positioning system, comprising an underwater mobile carrier and an underwater passive backscattering node, wherein the underwater mobile carrier includes a transceiver transducer array module and a processing module, wherein:

[0033] The transceiver array module is used to transmit a first transmission signal at the first position and a second transmission signal at the second position when the underwater mobile carrier moves from a first position to a second position along a preset direction;

[0034] The underwater passive backscattering node is used to receive the first transmitted signal and reflect the first reflected signal; and to receive the second transmitted signal and reflect the second reflected signal.

[0035] The transceiver array module is used to receive a first received signal corresponding to the first position and a second received signal corresponding to the second position; wherein, the first received signal includes the first transmitted signal and the first reflected signal, and the second received signal includes the second transmitted signal and the second reflected signal;

[0036] The processing module is used to determine the position of the underwater passive backscattering node based on the first position, the second position, the first received signal, and the second received signal.

[0037] The present invention also provides an underwater passive backscattering node positioning device, comprising:

[0038] The acquisition module is used to acquire a first received signal corresponding to the first position and a second received signal corresponding to the second position when the underwater mobile carrier moves from a first position to a second position along a preset direction; wherein, the first received signal includes a first transmitted signal of the underwater mobile carrier at the first position and a first reflected signal obtained by reflecting the first transmitted signal through an underwater passive backscattering node, and the second received signal includes a second transmitted signal of the underwater mobile carrier at the second position and a second reflected signal obtained by reflecting the second transmitted signal through an underwater passive backscattering node;

[0039] The positioning module is used to determine the position of the underwater passive backscattering node based on the first position, the second position, the first received signal, and the second received signal.

[0040] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the underwater passive backscattering node localization method as described above.

[0041] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the underwater passive backscattering node localization method as described above.

[0042] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the underwater passive backscattering node localization method as described above.

[0043] The underwater passive backscattering node positioning method, system, and apparatus provided by this invention, when an underwater mobile carrier moves along a preset direction from a first position to a second position, acquires a first received signal corresponding to the first position and a second received signal corresponding to the second position. The first received signal includes a first transmitted signal from the underwater mobile carrier at the first position and a first reflected signal obtained by reflecting the first transmitted signal through the underwater passive backscattering node. The second received signal includes a second transmitted signal from the underwater mobile carrier at the second position and a second reflected signal obtained by reflecting the second transmitted signal through the underwater passive backscattering node. Based on the first position, the second position, the first received signal, and the second received signal, the position of the underwater passive backscattering node is determined. This invention utilizes the piezoelectric effect of the underwater passive backscattering node for signal reflection and positions the underwater passive backscattering node based on the transmitted and reflected signals at the first and second positions, respectively. This eliminates the need to wake up the underwater passive backscattering node for time synchronization and communication, thus achieving the determination of the underwater passive backscattering node's position. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0045] Figure 1 This is a flowchart illustrating the underwater passive backscattering node localization method provided in an embodiment of the present invention.

[0046] Figure 2 This is a schematic diagram of the movement and positioning of an underwater mobile carrier provided in an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of the underwater passive backscattering node positioning device provided in an embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0050] Underwater acoustic backscattering is a relatively new technology, similar to RFID (Radio Frequency Identification) on land, but differing in that it utilizes the piezoelectric effect, replacing the antenna with a piezoelectric ceramic material. This piezoelectric ceramic material generates a potential difference when pressure is applied, and conversely, generates mechanical stress when a voltage is applied. Since acoustic signals propagate as pressure waves, they deform on the piezoelectric material when they reach the underwater passive backscattering node, causing the material to convert the pressure waves into voltage. More importantly, the piezoelectric effect is reversible, meaning that applying an electrical signal to the electrodes of a piezoelectric device can generate an acoustic signal. It is this reversibility that makes piezoelectric materials a key driver for realizing underwater acoustic backscattering communication.

[0051] A traditional underwater acoustic backscattering system generally consists of three parts: a sound source as the sound signal transmitter, a hydrophone as the signal receiver, and a passive backscattering node. This is a system that can be deployed as an underwater network with near-zero power. When the sound source transmits sound signals underwater, the passive backscattering node utilizes the piezoelectric effect to extract energy from these signals and communicates by modulating their reflections. Specifically, the passive backscattering node can transmit "0" bits by absorbing incident energy and "1" bits by reflecting incoming sound signals. It can also switch between reflection and absorption states by adjusting the voltage on the piezoelectric interface, and the voltage determines the vibration amplitude of the piezoelectric interface. The hydrophone receives the sound signals, senses the amplitude changes caused by reflection, decodes these changes, and completes the communication process.

[0052] To address the shortcomings of existing technologies that require intermittent wake-up of underwater passive backscattering nodes, which prevents time synchronization and communication, this invention provides a method for locating underwater passive backscattering nodes. Figure 1 This is a flowchart illustrating the underwater passive backscattering node localization method provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the underwater passive backscattering node localization method includes the following steps:

[0053] Step 110: When the underwater mobile carrier moves from the first position to the second position along a preset direction, acquire the first received signal corresponding to the first position and the second received signal corresponding to the second position; wherein, the first received signal includes the first transmitted signal of the underwater mobile carrier at the first position and the first reflected signal obtained by the reflection of the first transmitted signal through the underwater passive backscattering node, and the second received signal includes the second transmitted signal of the underwater mobile carrier at the second position and the second reflected signal obtained by the reflection of the second transmitted signal through the underwater passive backscattering node.

[0054] Specifically, the underwater mobile carrier can move from a first position to a second position along a preset direction, acquiring a first received signal corresponding to the first position and a second received signal corresponding to the second position. This preset direction can be set in advance as needed, and is not specifically limited herein.

[0055] Figure 2 This is a schematic diagram of the underwater mobile carrier's movement and positioning provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the first position of the underwater mobile vehicle is point (a, b) in the figure. The underwater mobile vehicle can transmit a first transmitted signal at the first position and receive a first received signal at the first position. The received first received signal may include the first transmitted signal and a first reflected signal after the first transmitted signal is reflected by the underwater passive backscattering node. The underwater mobile vehicle can move along the direction of the arrow (i.e., the preset direction) and reach the second position after moving a distance L. The second position is point (c, d) in the figure. The underwater mobile vehicle can transmit a second transmitted signal at the second position and receive a second received signal at the second position. The received second received signal may include the second transmitted signal and a second reflected signal after the second transmitted signal is reflected by the underwater passive backscattering node.

[0056] In one embodiment, the underwater passive backscattering node localization method further includes:

[0057] Determine the preset movement distance of the underwater mobile carrier;

[0058] The second position is determined based on the preset direction, the first position, and the preset moving distance.

[0059] Specifically, a preset movement distance for the underwater mobile carrier is determined. This preset movement distance can be pre-set as needed, and the present invention does not impose a specific limitation on it. The initial position of the underwater mobile carrier is the first position, and then the underwater mobile carrier can move in a preset direction, and the distance moved is the preset movement distance. The position reached by the underwater mobile carrier after the movement is completed is determined as the second position.

[0060] In the above embodiments, the second position is determined based on a preset direction, a first position, and a preset moving distance, which facilitates the positioning of the underwater passive backscattering node.

[0061] Step 120: Determine the location of the underwater passive backscattering node based on the first location, the second location, the first received signal, and the second received signal.

[0062] In one embodiment, determining the location of the underwater passive backscattering node based on the first location, the second location, the first received signal, and the second received signal includes:

[0063] Adaptive filtering is performed on the first received signal and the second received signal respectively to determine the first reflected signal from the first received signal and the second reflected signal from the second received signal.

[0064] The location of the underwater passive backscattering node is determined based on the first location, the second location, the first reflection signal, and the second reflection signal.

[0065] Specifically, the underwater mobile vehicle receives reflected signals from the underwater passive backscattering node, as well as its own emitted signals. Due to the significant attenuation of acoustic signals by water, the reflected signals are much weaker than the emitted signals, and are easily overwhelmed by the emitted signals. Therefore, to prevent the reflected signals from being overwhelmed by the emitted signals, it is necessary to determine the first reflected signal from the first received signal and the second reflected signal from the second received signal. Adaptive filtering can then be performed on the first and second received signals respectively, aiming to filter out the first emitted signal from the first received signal and the second emitted signal from the second received signal. After obtaining the first and second reflected signals, the position of the underwater passive backscattering node can be determined based on the first position, the second position, the first reflected signal, and the second reflected signal.

[0066] In the above embodiments, by performing adaptive filtering on the first received signal and the second received signal respectively, the problem of carrier interference is solved, a more accurate reflected signal can be obtained, and the location of the underwater passive backscattering node can be determined more accurately.

[0067] In one embodiment, the step of performing adaptive filtering on the first received signal and the second received signal respectively, determining a first reflected signal from the first received signal, and determining a second reflected signal from the second received signal includes:

[0068] For each of the first received signal and the second received signal, the following operations are performed:

[0069] The received signal is adaptively filtered based on the steepest descent method to determine the reflected signal from the received signal.

[0070] Specifically, the received signal is adaptively filtered based on the steepest descent method to determine the reflected signal. The first received signal can be denoted as x1(n), and the second received signal as x2(n). Taking the adaptive filtering of the first received signal x1(n) as an example, steps S1-S3 are repeated until the objective function J(n) is less than a preset threshold (this preset threshold can be pre-set as needed; this invention does not impose specific limitations):

[0071] S1. Determine the filtering result y1(n) of the first received signal x1(n) by adaptive filtering. The filtering result y1(n) can be determined by the following formula:

[0072] y1(n)=w z (n) T x1(n) (1)

[0073] Among them, w z (n) represents the weight coefficients of the filter, w z (n) T The weight coefficients w of the filter z The transpose of (n), where n represents the independent variable of the discrete signal and z represents the z-th filtering operation;

[0074] S2. Determine the objective function J(n) = E[e(n)] 2 Where, E[e(n)] 2 Let e(n) represent the expected value of the error signal; the error signal e(n) can be determined by the following formula:

[0075] e(n)=d(n)-y1(n) (2)

[0076] Where d(n) represents the desired signal;

[0077] S3. Compare the objective function J(n) with the preset threshold, and adjust the filter weight coefficients w. z (n) Updated to the weight coefficients w of the next filter. z+1 (n), the weight coefficients w of the next filter. z+1 (n) can be determined by the following formula:

[0078] w z+1 (n)=w z (n)+μx1(n) T e(n) (3)

[0079] Here, μ represents the step size factor, which can be used to control the descent rate of the objective function.

[0080] Then, the filtering result y1(n) of the last repeated steps S1-S3 is determined as the first reflected signal.

[0081] In the above embodiments, the received signal is adaptively filtered based on the steepest descent method, so that the objective function can converge quickly and a reflected signal that is closer to the actual value is obtained.

[0082] In one embodiment, determining the location of the underwater passive backscattering node based on the first location, the second location, the first reflected signal, and the second reflected signal includes:

[0083] The first signal arrival direction of the first reflected signal and the second signal arrival direction of the second reflected signal are determined respectively.

[0084] The location of the underwater passive backscattering node is determined based on the first location, the second location, the first signal arrival direction, and the second signal arrival direction.

[0085] Specifically, the process of determining the arrival direction of the first reflected signal is the same as the process of determining the arrival direction of the second reflected signal. For example, taking the determination of the arrival direction of the first reflected signal as an example, assuming the transceiver array of the underwater mobile carrier is a linear array with m array elements, an element spacing of d, and an incident angle of θ for the first reflected signal, the time delay difference τ between adjacent array elements can be determined by the following formula:

[0086]

[0087] Where c is the speed of sound in water.

[0088] Therefore, the frequency domain phase shift δ of the first received signal received by the array element can be modeled by the following mathematical expression:

[0089]

[0090] Where f is the frequency of the first received signal.

[0091] Furthermore, the frequency domain phase shift δ of the first received signal can be expressed as the following mathematical expression:

[0092]

[0093] Where λ is the wavelength of the first received signal.

[0094] The filtered result y1(n) of the first received signal x1(n) after adaptive filtering can be expressed by the following mathematical expression:

[0095]

[0096] Among them, s g (n) represents the first transmitted signal, i.e., the sound source signal vector, G is the number of underwater passive backscattering nodes, and h m (n) is the noise vector received by the array element.

[0097] Based on equation (7), the direction of arrival of a signal can be detected by a signal arrival direction detection model.

[0098] A signal arrival direction detection model can be, for example, a two-branch convolutional neural network structure. Each branch processes the real and imaginary parts of the filtered result y1(n) and feeds them into a convolutional layer for feature learning. Each branch consists of four convolutional layers, and max pooling is used to reduce the data dimensionality. After convolution operations are performed on the real and imaginary parts, dimensionality reduction and feature concatenation are performed on both matrices to form a one-dimensional feature vector. The cross-entropy of this one-dimensional feature vector is used as the loss function to output the first signal arrival direction β.

[0099] Before employing a signal arrival direction detection model to detect the direction of arrival of a signal, the model must first be trained. Specifically, multiple sets of training samples are first acquired, each set including the reflected signal and the signal arrival direction label. The reflected signal is then input into the signal arrival direction detection model, which processes the reflected signal and outputs the detected signal arrival direction. A loss function is constructed based on the detected signal arrival direction and its corresponding label to calculate the loss value. The parameters of the signal arrival direction detection model are then adjusted, completing one round of training for the model.

[0100] By training the signal arrival direction detection model through multiple rounds, a trained signal arrival direction detection model can be obtained after the model training termination condition is met. The trained signal arrival direction detection model has the ability to obtain the signal arrival direction based on the reflected signal. Then, by inputting the first reflected signal into the signal arrival direction detection model, the first signal arrival direction of the first reflected signal can be obtained; by inputting the second reflected signal into the signal arrival direction detection model, the second signal arrival direction of the second reflected signal can be obtained.

[0101] In the above embodiments, the first signal arrival direction of the first reflected signal and the second signal arrival direction of the second reflected signal were determined, laying the foundation for determining the location of the underwater passive backscattering node.

[0102] In one embodiment, determining the location of the underwater passive backscattering node based on the first location, the second location, the first signal arrival direction, and the second signal arrival direction includes:

[0103] Based on the first position, the direction of arrival of the first signal, and the preset direction, a first positioning ray is determined;

[0104] Based on the second position, the direction of arrival of the second signal, and the preset direction, a second positioning ray is determined;

[0105] The location of the underwater passive backscattering node is determined based on the first positioning ray and the second positioning ray.

[0106] Specifically, such as Figure 2 As shown, based on the first position (a, b) of the underwater mobile vehicle, the first signal arrival direction β, and as... Figure 2 The preset direction indicated by the middle arrow can determine the first positioning ray. Based on the second position (c, d) of the underwater mobile vehicle, the arrival direction α of the second signal, and as shown... Figure 2 The preset direction indicated by the middle arrow can determine the second positioning ray. Furthermore, the location of the underwater passive backscattering node can be determined based on the first and second positioning rays.

[0107] In the above embodiments, a first positioning ray is determined based on a first position, a first signal arrival direction, and a preset direction, and a second positioning ray is determined based on a second position, a second signal arrival direction, and a preset direction. The intersection of the first positioning ray and the second positioning ray is then determined as the position of the underwater passive backscattering node, thereby reducing the positioning error of the underwater passive backscattering node.

[0108] In one embodiment, the underwater passive backscattering node localization method further includes:

[0109] When the underwater mobile carrier is in the first position, a positioning combination signal is sent to the underwater passive backscattering node;

[0110] If the similarity value between the received reflected signal and the positioning combination signal is greater than or equal to a preset similarity threshold, the distance between the underwater mobile carrier and the underwater passive backscattering node is determined based on the transmission time of the positioning combination signal and the reception time of the reflected signal.

[0111] Determining the location of the underwater passive backscattering node based on the first positioning ray and the second positioning ray includes:

[0112] The intersection point between the first positioning ray and the second positioning ray is determined as the first positioning position;

[0113] The second positioning position is determined based on the first positioning ray and the distance between the underwater mobile carrier and the underwater passive backscattering node.

[0114] Based on the first positioning location and the second positioning location, the location of the underwater passive backscattering node is determined.

[0115] Specifically, when the underwater mobile vehicle is in its first position, it sends a positioning combination signal to the underwater passive backscattering node. Upon receiving the positioning combination signal, the underwater passive backscattering node experiences pressure, creating a potential difference that generates mechanical stress and deformation, converting the pressure into voltage. This voltage can then be used to generate an acoustic signal, i.e., a reflected signal of the positioning combination signal. This piezoelectric effect results in a high similarity between the positioning combination signal and the reflected signal.

[0116] Therefore, if the underwater mobile vehicle receives a reflected signal with a similarity value (which can be one or more of waveform similarity, amplitude similarity, frequency similarity, and phase similarity, without specific limitation in this invention) greater than or equal to a preset similarity threshold, it can be determined that the reflected signal is the reflected signal corresponding to the positioning combination signal. The preset similarity threshold is pre-set and corresponds to the similarity value.

[0117] Then, the underwater mobile vehicle determines the distance between the underwater mobile vehicle and the underwater passive backscattering node based on the transmission time of the positioning combination signal and the reception time of the reflected signal. That is, the distance between the underwater mobile vehicle and the underwater passive backscattering node is determined according to the time difference between the transmission time of the positioning combination signal and the reception time of the reflected signal and the signal propagation speed.

[0118] Furthermore, the intersection point (p, q) of the first and second positioning rays can be used as the first positioning location of the underwater passive backscattering node. The second positioning location can also be determined based on the first positioning ray and the distance between the underwater mobile carrier and the underwater passive backscattering node. Finally, the location of the underwater passive backscattering node is determined based on the first and second positioning locations. For example, the midpoint between the first and second positioning locations can be used as the location of the underwater passive backscattering node.

[0119] In the above embodiment, the intersection of the first positioning ray and the second positioning ray is determined as the first positioning position. Based on the first positioning ray and the distance between the underwater mobile carrier and the underwater passive backscattering node, the second positioning position is determined. Finally, based on the first positioning position and the second positioning position, the position of the underwater passive backscattering node is determined, making the determined position of the underwater passive backscattering node more accurate.

[0120] The underwater passive backscattering node positioning method provided by this invention involves acquiring a first received signal corresponding to the first position and a second received signal corresponding to the second position when an underwater mobile vehicle moves along a preset direction from a first position to a second position. The first received signal includes a first transmitted signal from the underwater mobile vehicle at the first position and a first reflected signal obtained by reflecting the first transmitted signal through the underwater passive backscattering node. The second received signal includes a second transmitted signal from the underwater mobile vehicle at the second position and a second reflected signal obtained by reflecting the second transmitted signal through the underwater passive backscattering node. Based on the first position, the second position, the first received signal, and the second received signal, the position of the underwater passive backscattering node is determined. This invention utilizes the piezoelectric effect of the underwater passive backscattering node for signal reflection and positions the underwater passive backscattering node based on the transmitted and reflected signals at the first and second positions, respectively. This method achieves the determination of the underwater passive backscattering node's position without needing to wake it up for time synchronization and communication.

[0121] This invention also provides an underwater passive backscattering node positioning system, comprising an underwater mobile carrier and an underwater passive backscattering node, wherein the underwater mobile carrier includes a transceiver transducer array module and a processing module, wherein:

[0122] The transceiver array module is used to transmit a first transmission signal at the first position and a second transmission signal at the second position when the underwater mobile carrier moves from a first position to a second position along a preset direction;

[0123] The underwater passive backscattering node is used to receive the first transmitted signal and reflect the first reflected signal; and to receive the second transmitted signal and reflect the second reflected signal.

[0124] The transceiver array module is used to receive a first received signal corresponding to the first position and a second received signal corresponding to the second position; wherein, the first received signal includes the first transmitted signal and the first reflected signal, and the second received signal includes the second transmitted signal and the second reflected signal;

[0125] The processing module is used to determine the position of the underwater passive backscattering node based on the first position, the second position, the first received signal, and the second received signal.

[0126] Specifically, the transceiver array module may include multiple transceiver elements. Some transceiver elements are used to transmit a first transmitted signal and a second transmitted signal, while others are used to receive a first received signal and a second received signal. Using a combined transceiver array ensures that the signal transmitting device and the signal receiving device are aligned, reducing the positioning error of the underwater passive backscattering node.

[0127] Optionally, the underwater passive backscattering node may also include a sensing module, an energy harvesting module, and a reflection modulation module. The sensing module is used to receive each transmitted signal; the energy harvesting module is used to harvest piezoelectric energy and can use the harvested piezoelectric energy to power the reflection modulation module; the reflection modulation module is used to reflect each reflected signal.

[0128] Optionally, the underwater passive backscattering node positioning system may also include an inertial navigation module for detecting the movement distance of the underwater mobile vehicle.

[0129] The underwater passive backscattering node positioning device provided by the present invention is described below. The underwater passive backscattering node positioning device described below can be referred to in correspondence with the underwater passive backscattering node positioning method described above.

[0130] Figure 3 This is a schematic diagram of the underwater passive backscattering node positioning device provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the underwater passive backscattering node positioning device 300 includes:

[0131] The acquisition module 310 is used to acquire a first received signal corresponding to the first position and a second received signal corresponding to the second position when the underwater mobile carrier moves from a first position to a second position along a preset direction; wherein, the first received signal includes a first transmitted signal of the underwater mobile carrier at the first position and a first reflected signal obtained by reflecting the first transmitted signal through an underwater passive backscattering node, and the second received signal includes a second transmitted signal of the underwater mobile carrier at the second position and a second reflected signal obtained by reflecting the second transmitted signal through an underwater passive backscattering node;

[0132] The positioning module 320 is used to determine the position of the underwater passive backscattering node based on the first position, the second position, the first received signal, and the second received signal.

[0133] The underwater passive backscattering node positioning device provided by this invention acquires a first received signal corresponding to the first position and a second received signal corresponding to the second position when an underwater mobile carrier moves along a preset direction from a first position to a second position. The first received signal includes a first transmitted signal from the underwater mobile carrier at the first position and a first reflected signal obtained by reflecting the first transmitted signal through the underwater passive backscattering node. The second received signal includes a second transmitted signal from the underwater mobile carrier at the second position and a second reflected signal obtained by reflecting the second transmitted signal through the underwater passive backscattering node. Based on the first position, the second position, the first received signal, and the second received signal, the position of the underwater passive backscattering node is determined. This invention utilizes the piezoelectric effect of the underwater passive backscattering node for signal reflection and positions the underwater passive backscattering node based on the transmitted and reflected signals at the first and second positions, respectively. This eliminates the need to wake up the underwater passive backscattering node for time synchronization and communication, thus enabling the determination of the underwater passive backscattering node's position.

[0134] In one embodiment, the positioning module 320 is specifically used for:

[0135] Adaptive filtering is performed on the first received signal and the second received signal respectively to determine the first reflected signal from the first received signal and the second reflected signal from the second received signal.

[0136] The location of the underwater passive backscattering node is determined based on the first location, the second location, the first reflection signal, and the second reflection signal.

[0137] In one embodiment, the positioning module 320 is specifically used for:

[0138] The first signal arrival direction of the first reflected signal and the second signal arrival direction of the second reflected signal are determined respectively.

[0139] The location of the underwater passive backscattering node is determined based on the first location, the second location, the first signal arrival direction, and the second signal arrival direction.

[0140] In one embodiment, the positioning module 320 is specifically used for:

[0141] Based on the first position, the direction of arrival of the first signal, and the preset direction, a first positioning ray is determined;

[0142] Based on the second position, the direction of arrival of the second signal, and the preset direction, a second positioning ray is determined;

[0143] The location of the underwater passive backscattering node is determined based on the first positioning ray and the second positioning ray.

[0144] In one embodiment, the positioning module 320 is specifically used for:

[0145] When the underwater mobile carrier is in the first position, a positioning combination signal is sent to the underwater passive backscattering node;

[0146] If the similarity value between the received reflected signal and the positioning combination signal is greater than or equal to a preset similarity threshold, the distance between the underwater mobile carrier and the underwater passive backscattering node is determined based on the transmission time of the positioning combination signal and the reception time of the reflected signal.

[0147] Also used for:

[0148] The intersection point between the first positioning ray and the second positioning ray is determined as the first positioning position;

[0149] The second positioning position is determined based on the first positioning ray and the distance between the underwater mobile carrier and the underwater passive backscattering node.

[0150] Based on the first positioning location and the second positioning location, the location of the underwater passive backscattering node is determined.

[0151] In one embodiment, the positioning module 320 is specifically used for:

[0152] For each of the first received signal and the second received signal, the following operations are performed:

[0153] The received signal is adaptively filtered based on the steepest descent method to determine the reflected signal from the received signal.

[0154] In one embodiment, the underwater passive backscattering node positioning device further includes a determining module, which is specifically used for:

[0155] Determine the preset movement distance of the underwater mobile carrier;

[0156] The second position is determined based on the preset direction, the first position, and the preset moving distance.

[0157] Figure 4 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 4As shown, the electronic device may include: a processor 410, a communication interface 420, a memory 430, and a communication bus 440, wherein the processor 410, the communication interface 420, and the memory 430 communicate with each other through the communication bus 440. The processor 410 can call logical instructions in the memory 430 to execute an underwater passive backscattering node localization method, which includes:

[0158] When an underwater mobile carrier moves from a first position to a second position along a preset direction, a first received signal corresponding to the first position and a second received signal corresponding to the second position are acquired; wherein, the first received signal includes a first transmitted signal of the underwater mobile carrier at the first position and a first reflected signal obtained by reflecting the first transmitted signal through an underwater passive backscattering node, and the second received signal includes a second transmitted signal of the underwater mobile carrier at the second position and a second reflected signal obtained by reflecting the second transmitted signal through an underwater passive backscattering node;

[0159] The location of the underwater passive backscattering node is determined based on the first location, the second location, the first received signal, and the second received signal.

[0160] Furthermore, the logical instructions in the aforementioned memory 430 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0161] On the other hand, the present invention also provides a computer program product, the computer program product comprising a computer program that can be stored on a non-transitory computer-readable storage medium, wherein when the computer program is executed by a processor, the computer is able to execute the underwater passive backscattering node localization method provided by the above methods, the method comprising:

[0162] When an underwater mobile carrier moves from a first position to a second position along a preset direction, a first received signal corresponding to the first position and a second received signal corresponding to the second position are acquired; wherein, the first received signal includes a first transmitted signal of the underwater mobile carrier at the first position and a first reflected signal obtained by reflecting the first transmitted signal through an underwater passive backscattering node, and the second received signal includes a second transmitted signal of the underwater mobile carrier at the second position and a second reflected signal obtained by reflecting the second transmitted signal through an underwater passive backscattering node;

[0163] The location of the underwater passive backscattering node is determined based on the first location, the second location, the first received signal, and the second received signal.

[0164] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the underwater passive backscattering node localization method provided by the methods described above, the method comprising:

[0165] When an underwater mobile carrier moves from a first position to a second position along a preset direction, a first received signal corresponding to the first position and a second received signal corresponding to the second position are acquired; wherein, the first received signal includes a first transmitted signal of the underwater mobile carrier at the first position and a first reflected signal obtained by reflecting the first transmitted signal through an underwater passive backscattering node, and the second received signal includes a second transmitted signal of the underwater mobile carrier at the second position and a second reflected signal obtained by reflecting the second transmitted signal through an underwater passive backscattering node;

[0166] The location of the underwater passive backscattering node is determined based on the first location, the second location, the first received signal, and the second received signal.

[0167] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0168] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0169] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for underwater passive backscatter node localization, the method comprising: include: When an underwater mobile carrier moves from a first position to a second position along a preset direction, a first received signal corresponding to the first position and a second received signal corresponding to the second position are acquired; wherein, the first received signal includes a first transmitted signal of the underwater mobile carrier at the first position and a first reflected signal obtained by reflecting the first transmitted signal through an underwater passive backscattering node, and the second received signal includes a second transmitted signal of the underwater mobile carrier at the second position and a second reflected signal obtained by reflecting the second transmitted signal through an underwater passive backscattering node; Based on the first location, the second location, the first received signal, and the second received signal, the location of the underwater passive backscattering node is determined; Determining the location of the underwater passive backscattering node based on the first location, the second location, the first received signal, and the second received signal includes: Adaptive filtering is performed on the first received signal and the second received signal respectively to determine the first reflected signal from the first received signal and the second reflected signal from the second received signal. Based on the first position, the second position, the first reflection signal, and the second reflection signal, the position of the underwater passive backscattering node is determined; Determining the location of the underwater passive backscattering node based on the first location, the second location, the first reflection signal, and the second reflection signal includes: The first signal arrival direction of the first reflected signal and the second signal arrival direction of the second reflected signal are determined respectively. The location of the underwater passive backscattering node is determined based on the first location, the second location, the first signal arrival direction, and the second signal arrival direction; Determining the location of the underwater passive backscattering node based on the first location, the second location, the first signal arrival direction, and the second signal arrival direction includes: Based on the first position, the direction of arrival of the first signal, and the preset direction, a first positioning ray is determined; Based on the second position, the direction of arrival of the second signal, and the preset direction, a second positioning ray is determined; The location of the underwater passive backscattering node is determined based on the first positioning ray and the second positioning ray.

2. The method according to claim 1, characterized in that, The method further includes: When the underwater mobile carrier is in the first position, a positioning combination signal is sent to the underwater passive backscattering node; If the similarity value between the received reflected signal and the positioning combination signal is greater than or equal to a preset similarity threshold, the distance between the underwater mobile carrier and the underwater passive backscattering node is determined based on the transmission time of the positioning combination signal and the reception time of the reflected signal. Determining the location of the underwater passive backscattering node based on the first positioning ray and the second positioning ray includes: The intersection point between the first positioning ray and the second positioning ray is determined as the first positioning position; The second positioning position is determined based on the first positioning ray and the distance between the underwater mobile carrier and the underwater passive backscattering node. Based on the first positioning location and the second positioning location, the location of the underwater passive backscattering node is determined.

3. The method according to claim 1 or 2, characterized in that, The step of performing adaptive filtering on the first received signal and the second received signal respectively, determining the first reflected signal from the first received signal, and determining the second reflected signal from the second received signal includes: For each of the first received signal and the second received signal, the following operations are performed: The received signal is adaptively filtered based on the steepest descent method to determine the reflected signal from the received signal.

4. The method according to claim 1 or 2, characterized in that, The method further includes: Determine the preset movement distance of the underwater mobile carrier; The second position is determined based on the preset direction, the first position, and the preset moving distance.

5. An underwater passive backscatter node localization system applied to the underwater passive backscatter node localization method according to any one of claims 1 to 4, characterized in that, It includes an underwater mobile carrier and an underwater passive backscattering node. The underwater mobile carrier includes a transceiver transducer array module and a processing module, wherein: The transceiver array module is used to transmit a first transmission signal at the first position and a second transmission signal at the second position when the underwater mobile carrier moves from a first position to a second position along a preset direction; The underwater passive backscattering node is used to receive the first transmitted signal and reflect the first reflected signal; and to receive the second transmitted signal and reflect the second reflected signal. The transceiver array module is used to receive a first received signal corresponding to the first position and a second received signal corresponding to the second position; wherein, the first received signal includes the first transmitted signal and the first reflected signal, and the second received signal includes the second transmitted signal and the second reflected signal; The processing module is used to determine the position of the underwater passive backscattering node based on the first position, the second position, the first received signal, and the second received signal.

6. An underwater passive backscatter node positioning device applied to the underwater passive backscatter node positioning method according to any one of claims 1 to 4, characterized in that, include: The acquisition module is used to acquire a first received signal corresponding to the first position and a second received signal corresponding to the second position when the underwater mobile carrier moves from a first position to a second position along a preset direction; wherein, the first received signal includes a first transmitted signal of the underwater mobile carrier at the first position and a first reflected signal obtained by reflecting the first transmitted signal through an underwater passive backscattering node, and the second received signal includes a second transmitted signal of the underwater mobile carrier at the second position and a second reflected signal obtained by reflecting the second transmitted signal through an underwater passive backscattering node; The positioning module is used to determine the position of the underwater passive backscattering node based on the first position, the second position, the first received signal, and the second received signal.

7. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the underwater passive backscattering node localization method as described in any one of claims 1 to 4.

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