Underwater distance measurement method and device based on multi-domain processing, and storage medium
Through multi-domain processing technology, combined with dynamic compensation of sound velocity profile and pseudo-random noise coding, the accuracy and security problems of traditional underwater ranging technology are solved, and high-precision, low-power and high-security underwater ranging is achieved.
Patent Information
- Application Number
- CN202511121037.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-12
- Publication Date
- 2025-10-03
AI Technical Summary
Traditional underwater ranging technology has problems such as low accuracy, limited transmission distance and susceptibility to environmental influences.
An underwater ranging method based on multi-domain processing is adopted. Through precise time segmentation and pseudo-random noise coding, combined with dynamic compensation of sound velocity profile, anti-multipath waveform design and multi-domain joint signal processing, the ranging accuracy and anti-interference capability are improved, and the security of the ranging process is enhanced through multipath fingerprint hash authentication technology.
It achieves high-precision, low-power and high-security underwater ranging, meeting various application requirements in underwater environments.
Smart Images
Figure CN120742291A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of underwater ranging, and in particular to an underwater ranging method, device and storage medium based on multi-domain processing. Background Art
[0002] The underwater ranging system was developed to meet the high requirements for precise positioning and ranging of underwater targets in marine resource development, underwater engineering construction and marine safety. Traditional technologies such as acoustic ranging and optical ranging have shortcomings such as low accuracy, limited transmission distance and susceptibility to environmental influences. Summary of the Invention
[0003] To address the above problems, the present invention provides an underwater ranging method, device, and storage medium based on multi-domain processing. These methods improve ranging accuracy and anti-interference capabilities through precise time segmentation and pseudo-random noise encoding, and enhance the security and reliability of the ranging process through security measures such as encryption and authentication. These methods offer significant advantages over traditional technologies.
[0004] In order to achieve the above object, the present invention provides the following technical solutions: In one aspect, an embodiment of the present invention provides an underwater ranging method based on multi-domain processing, the method comprising the following steps: S100, a transmitting end outputs a transmission signal along multiple paths, and generates a first hash value for each path using a channel impulse response: the transmission signal is jointly modulated by linear frequency modulation and pseudo-random noise; S200, the receiving end extracts a channel impulse response, generates a second hash value based on the extracted channel impulse response, and compares the second hash value with the first hash value; S300, if the comparison passes, performing phase compensation on the received signals received by the multiple array elements to obtain an input signal after spatial beamforming; S400, performing multi-scale decomposition on the input signal to obtain detail coefficients at different scales, and reconstructing the detail coefficients to obtain a denoised signal; S500, generating a filtered signal according to the channel impulse response and the denoised signal; S600, selecting multiple front paths, performing amplitude and delay detection on filtered signals of the multiple paths, and weighted combining the amplitudes and delays of the detected multiple filtered signals to obtain a rear delay estimate; S700, obtaining a ranging result based on the post-delay estimation and underwater sound speed calculation; the underwater sound speed is determined based on the depth, temperature and salinity.
[0005] Optionally, the expression of the transmitted signal is: ; in, To transmit the signal, is the amplitude, is the starting frequency, is the launch time, is the bandwidth, is the pulse width, is the Gold code length, is the index of the Gold code length, is the Gold code sequence, is the chip width, and rect() is the rectangle function.
[0006] Optionally, the channel impulse response is expressed as: ; The expression of the first hash value is: ; in: is the magnitude of the kth path, is the delay of the kth path, L is the number of paths, is the PRN code sequence, is the first hash value, Used to characterize the ideal transmission delay of the k-th path signal.
[0007] Optionally, the input signal is expressed as: ; in, is the input signal after spatial beamforming, is the weight, is the number of array elements, is the index of the array element, is the received signal received by the mth array element, is the receiving time difference of the mth array element.
[0008] Optionally, the expression of the detail coefficient is: ; in, is the noise standard deviation, N is the signal length, is the detail coefficient at the jth scale, is the hard threshold.
[0009] Optionally, the expression of the filtered signal is: ; in, is the filtered signal, is the magnitude of the kth path, is the delay of the kth path, and L is the number of paths.
[0010] Optionally, the expression for the post-delay estimation is: ; in, For post-delay estimation.
[0011] Optionally, the expression for the underwater sound speed is: ; Where c(z) is the underwater sound speed at depth z, T is the temperature, S is the salinity, and z is the depth.
[0012] In another aspect, an embodiment of the present invention provides an electronic device, including: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the above method.
[0013] On the other hand, an embodiment of the present invention provides a computer-readable storage medium storing a program executable by a processor. When the program is executed by the processor, it is used to perform any of the above methods.
[0014] The beneficial effects of the present invention are as follows: the present invention discloses an underwater ranging method, device and storage medium based on multi-domain processing. The present invention improves the accuracy and reliability of underwater ranging through dynamic compensation of sound velocity profile, anti-multipath waveform design, and multi-domain joint signal processing, and ensures the security of the ranging process through multipath fingerprint hash authentication technology, thereby achieving high-precision, high-reliability, low-power consumption and high-security underwater ranging, meeting various application requirements in underwater environments. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0016] Figure 1 1 is a flow chart of an underwater ranging method based on multi-domain processing according to an embodiment of the present invention; Figure 2 It is a structural diagram of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION
[0017] The following will be combined with the embodiments and drawings to clearly and completely describe the concept, specific structure and technical effects disclosed in the present invention, so as to fully understand the purpose, scheme and effect disclosed in the present invention. It should be noted that the embodiments and features in the embodiments of this application can be combined with each other unless there is a conflict.
[0018] refer to Figure 1 ,like Figure 1 FIG. 1 is a diagram illustrating an underwater ranging method based on multi-domain processing provided by an embodiment of the present invention, the method comprising the following steps: S100, a transmitting end outputs a transmission signal along multiple paths, and generates a first hash value for each path using a channel impulse response: the transmission signal is jointly modulated by linear frequency modulation and pseudo-random noise; S200, the receiving end extracts a channel impulse response, generates a second hash value based on the extracted channel impulse response, and compares the second hash value with the first hash value; S300, if the comparison passes, performing phase compensation on the received signals received by the multiple array elements to obtain an input signal after spatial beamforming; S400, performing multi-scale decomposition on the input signal to obtain detail coefficients at different scales, and reconstructing the detail coefficients to obtain a denoised signal; S500, generating a filtered signal according to the channel impulse response and the denoised signal; S600, selecting multiple front paths, performing amplitude and delay detection on filtered signals of the multiple paths, and weighted combining the amplitudes and delays of the detected multiple filtered signals to obtain a rear delay estimate; S700, obtaining a ranging result based on the post-delay estimation and underwater sound speed calculation; the underwater sound speed is determined based on the depth, temperature and salinity.
[0019] Specifically, the method of designing underwater acoustic physical characteristics and signals is as follows; In underwater environments, the speed of sound isn't fixed; it varies with depth, temperature, and salinity. These changes affect the propagation time and path of sound waves, thus affecting the accuracy of distance measurement. To accurately measure underwater distances, dynamic compensation for the speed of sound is necessary.
[0020] In some embodiments, the underwater sound speed is expressed as: ; Where c(z) is the underwater sound speed at depth z, T is the temperature, S is the salinity, and z is the depth.
[0021] In this embodiment, real-time in-situ measurements are performed by the temperature-salinity-depth sensor (CTD) carried by the node. The sound velocity gradient changes are dynamically corrected by the synchronously acquired real-time measured ocean environmental parameters such as temperature T, salinity S, and depth z, thereby achieving real-time compensation of the sound propagation path.
[0022] In underwater environments, sound waves can generate multiple propagation paths due to reflection and refraction, a phenomenon known as multipath. Multipath can cause signal interference, affecting signal clarity and ranging accuracy. To address the signal interference and ranging distortion caused by multipath due to sound wave reflection and refraction, this invention employs a composite signal model based on combined linear frequency modulation (LFM) and pseudorandom noise (PRN) modulation in underwater anti-multipath waveform design.
[0023] The transmission signal is a transmission signal jointly modulated by linear frequency modulation (LFM) and pseudo random noise (PRN); The expression of the transmitted signal is: ; in, To transmit the signal, is the amplitude, is the starting frequency, is the launch time, is the bandwidth, is the pulse width, is the Gold code length, is the index of the Gold code length, is the Gold code sequence, is the chip width, and rect() is the rectangle function.
[0024] In some specific embodiments, the parameters related to linear frequency modulation are set to: starting frequency ,bandwidth , pulse width ; The parameters related to pseudo-random noise are set to: Gold code length , chip width (Bandwidth 1kHz), is a Gold code sequence; the bandwidth of the LFM signal is wide, which can provide higher resolution: , c is the speed of sound, B is the bandwidth. Through the sharp autocorrelation characteristics of the PRN code (the sidelobe suppression ratio is about ) suppresses false multipath peaks and enhances signal delay resolution. Chirp provides the physical foundation for high-resolution ranging, while the PRN code imparts communication resilience against multipath and interference. The coordinated parameters of the two (such as Tc = 1ms and B = 10kHz bandwidth matching) ensure a balance between multipath suppression and ranging accuracy.
[0025] In underwater environments, sound waves can generate multiple propagation paths due to reflection and refraction, a phenomenon known as multipath. Multipath can cause signal interference, affecting signal clarity and ranging accuracy. Combining LFM (Linear Frequency Modulation) and PRN (Pseudo-Random Noise) technology can significantly improve the ranging accuracy of underwater acoustic signals and reduce ranging errors.
[0026] Based on the above embodiment, it can be seen that the PRN code sequence Embedded into the transmit waveform as known parameters In order to increase the security of the signal, this embodiment adds multipath fingerprint hash authentication and extracts the channel impulse response model, which is expressed as: ; Using the multipath physical fingerprint (path amplitude , delay and the number of paths L), combined with the pseudo-random noise (PRN) Gold code sequence embedded at the transmitter , using lightweight hash algorithm BLAKE2s to calculate multipath parameters and Perform a hybrid hash operation to generate a unique identifier H. In some embodiments, the expression of the first hash value is: ; in: is the magnitude of the kth path, is the delay of the kth path, L is the number of paths, is the PRN code sequence, is the first hash value, Used to characterize the ideal transmission delay of the k-th path signal.
[0027] It should be noted that the PRN code sequence As part of the transmitted signal, it directly participates in the generation of the hash value.
[0028] This embodiment is based on the non-cloning property of the physical space of the underwater channel and utilizes the sensitivity of the multipath propagation path to the geometric structure of the environment and the medium parameters, so that the first hash value H has strong non-forgeability; at the same time, the PRN code participates in the hash construction as a priori key, which is achieved through the chip width. The temporal constraints of the entropy source enhance the randomness, and the dual identity of the signal carrier is used to achieve cross-layer parameter reuse. Through fixed-length parameter compression and parallel hash processing, the computational complexity is reduced to O(1), adapting to the limited computing power of underwater nodes. It provides physical layer native terminal identity authentication and anti-replay attack capabilities for dynamic underwater environments, effectively resisting security threats such as node impersonation and signal tampering, and forming a seamless mapping from channel physical characteristics to cryptographic security credentials.
[0029] In order to solve the problem of spatial interference suppression and target signal enhancement in complex underwater acoustic environments, this embodiment proposes spatial beamforming technology in multi-domain joint signal processing, which performs spatial filtering and enhancement on acoustic signals through a multi-element receiver. Delay compensated Eliminate Direction of Arrival After the propagation delay difference is calculated, the optimal weight vector is solved based on the minimum variance distortionless response (MVDR) criterion. , that is, construct a constrained optimization problem: ,satisfy ; is the conjugate transpose of the weight vector w, is the noise covariance matrix; is the target direction steering vector; the weights are calculated in real time through eigenvalue decomposition or adaptive algorithm, and the final signal is output. After spatial beamforming, the obtained signal y(t) has suppressed sidelobe interference to a certain extent and improved the signal-to-noise ratio.
[0030] In some embodiments, the input signal is expressed as: ; in, is the input signal after spatial beamforming, is the weight, is the number of array elements, is the index of the array element, is the received signal received by the mth array element, is the receiving time difference of the mth array element.
[0031] Received signal received by multi-element receiver Directivity gain is achieved through phase compensation. After spatial beamforming, the obtained signal y(t) has suppressed sidelobe interference to a certain extent and improved the signal-to-noise ratio.
[0032] In order to further eliminate the residual non-stationary interference and broadband noise after spatial beamforming, and improve the signal delay resolution and feature extraction robustness, the signal y(t) after spatial beamforming is used as the input signal and the input signal is subjected to wavelet threshold denoising. y(t) is decomposed at multiple scales to obtain detail coefficients at different scales. , using hard thresholding Processing detail coefficient: In some embodiments, the expression of the detail coefficient is: ; in, is the noise standard deviation, N is the signal length, is the detail coefficient at the jth scale, is the hard threshold.
[0033] Threshold $by noise standard deviation (estimated by the high-frequency sub-band of the signal) and the signal length N are adaptively determined, and the thresholded coefficients are finally Perform inverse wavelet transform to reconstruct the denoised signal By reconstructing the processed detail coefficients, the denoised signal is obtained .
[0034] Adaptive matched filtering technology is based on denoising signal $ and channel impulse response The physical characteristics of the optimal detection filter are dynamically constructed; specifically, the denoised signal As input, the receiver uses the channel impulse response Dynamically adjust the filter to obtain the filtered signal; In some embodiments, the expression of the filtered signal is: ; in, is the filtered signal, is the magnitude of the kth path, is the delay of the kth path, L is the number of paths, is the conjugate inverse form of the channel response, To transmit a signal The autocorrelation function of .
[0035] In this embodiment, the multipath parameter The real-time feedback of the matched filter is used to adaptively match the impulse response of the matched filter to the current channel state, so that the signal components of each path are coherently superimposed in the time domain (amplitude weighting factor ), and using the autocorrelation function The delay resolution characteristics (main lobe width ) to separate the aliased interference of multipath peaks.
[0036] The multipath merging strategy detects the amplitude of the first L=3 paths { } and delay { }, construct amplitude-weighted combined delay .
[0037] Weighted merging: weighted merging of detected paths to calculate the delay estimate : In some embodiments, the expression for the post-delay estimate is: ; in, For post-delay estimation.
[0038] Ranging error reduction: Through multipath merging strategy, the ranging error is reduced to that of a single path. This means that as the number of detected paths increases, ranging errors are significantly reduced. Furthermore, the system breaks through the Rayleigh resolution limit, achieving sub-wavelength ranging accuracy, transforming multipath interference into beneficial signals and improving robustness in complex environments.
[0039] Multi-domain joint signal processing effectively improves the reception quality and ranging accuracy of underwater acoustic signals through spatial beamforming, ocean environment noise suppression and multipath energy suppression algorithms.
[0040] Through the above-mentioned dynamic compensation of sound velocity profile, anti-multipath waveform design, multi-domain joint signal processing and other technical means, high precision and high reliability of underwater ranging can be finally achieved. The ranging result can be obtained by formula / 2 is calculated. The channel impulse response h(t) is extracted at the receiving end to generate a hash value H, which is then compared with the hash value at the transmitting end to verify the authenticity and integrity of the signal.
[0041] Underwater high-precision ranging through real-time correction Time delay , to achieve the ranging value Sub-meter accuracy. Subsequently, dynamic channel hash verification is performed: the receiving end generates a complete hash value , the expression is: Then, only the fixed interval (such as the 8th to 24th bits, a total of 16 bits) is compared, which encodes the multipath delay. Quantization value and PRN code segment The mixed entropy source is less affected by environmental disturbances; the transmitter pre-stores the reference hash The same interval, through strict bit consistency Verify the authenticity of the signal. At the same time, the physical layer constraint check: the number of detection paths , delay mutation , exclude non-physical attacks. Verify the authenticity and integrity of the signal.
[0042] Compared with the related art, the present invention has the following beneficial effects: High-precision ranging: This technology achieves high-precision signal measurement through precise time segmentation and pseudo-random noise encoding, thereby improving the accuracy of underwater ranging. In contrast, traditional acoustic ranging technology has lower ranging accuracy due to factors such as slow signal propagation speed and multipath effects.
[0043] Strong anti-interference capability: This technology uses pseudo-random noise coding, which makes the signal highly resistant to interference during transmission. Even in complex underwater environments, such as those with multipath effects and ambient noise, this technology can still maintain high ranging accuracy and stability.
[0044] Enhanced security: The underwater security protection and anti-spoofing ranging solution based on multi-domain processing effectively prevents ranging signals from being stolen or tampered with through security measures such as encryption and authentication, ensuring the security and reliability of the underwater ranging process. This is of great significance for security-critical applications such as underwater communications and underwater safety monitoring.
[0045] refer to Figure 2 , an embodiment of the present invention further provides an electronic device, including: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the above method.
[0046] The contents of the above method embodiments are all applicable to this embodiment. The functions specifically implemented by this embodiment are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments, which will not be repeated here.
[0047] In addition, an embodiment of the present invention further provides a computer-readable storage medium, which stores computer-executable instructions, and the computer-executable instructions are used to execute the above method.
[0048] Since the computer-readable storage medium of an embodiment of the present invention can execute the air conditioner control method of any of the above embodiments, the specific implementation methods and technical effects of the computer-readable storage medium of an embodiment of the present invention can refer to the specific implementation methods and technical effects of the air conditioner control method of any of the above embodiments.
[0049] In addition, the embodiments of the present application further disclose a computer program product or computer program, which is stored in a computer-readable storage medium. The processor of a computer device can read the computer program from the computer-readable storage medium, and the processor executes the computer program, so that the computer device performs the above-mentioned method. Similarly, the contents of the above-mentioned method embodiment are all applicable to the present storage medium embodiment, and the functions specifically implemented by the present storage medium embodiment are the same as those of the above-mentioned method embodiment, and the beneficial effects achieved are also the same as those achieved by the above-mentioned method embodiment.
[0050] Those skilled in the art will appreciate that all or some of the methods and systems disclosed above can be implemented as software, firmware, hardware, or any suitable combination thereof. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on computer-readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). As is well known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVDs) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. Furthermore, as is well known to those skilled in the art, communication media typically embodies computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.
[0051] The above is a specific description of the preferred implementation of the present disclosure, but the present disclosure is not limited to the above-mentioned implementation mode. Technical personnel familiar with the art can also make various equivalent modifications or substitutions without violating the spirit of the present disclosure. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present disclosure.
Claims
1. An underwater ranging method based on multi-domain processing, characterized in that: The method comprises the following steps: S100, a transmitting end outputs a transmission signal along multiple paths, and generates a first hash value for each path using a channel impulse response: the transmission signal is obtained by jointly modulating linear frequency modulation and pseudo-random noise; S200, the receiving end extracts a channel impulse response, generates a second hash value based on the extracted channel impulse response, and compares the second hash value with the first hash value; S300, if the comparison passes, performing phase compensation on the received signals received by the multiple array elements to obtain an input signal after spatial beamforming; S400, performing multi-scale decomposition on the input signal to obtain detail coefficients at different scales, and reconstructing the detail coefficients to obtain a denoised signal; S500, generating a filtered signal according to the channel impulse response and the denoised signal; S600, selecting multiple front paths, performing amplitude and delay detection on filtered signals of the multiple paths, and weighted combining the amplitudes and delays of the detected multiple filtered signals to obtain a rear delay estimate; S700, obtaining a ranging result based on the post-delay estimation and underwater sound speed calculation; the underwater sound speed is determined based on the depth, temperature and salinity.
2. The method according to claim 1, characterized in that The expression of the transmission signal is: ； in, To transmit the signal, is the amplitude, is the starting frequency, is the launch time, is the bandwidth, is the pulse width, is the Gold code length, is the index of the Gold code length, is the Gold code sequence, is the chip width, and rect() is the rectangle function.
3. The method according to claim 1, characterized in that The expression of the channel impulse response is: ； The expression of the first hash value is: ； in: is the magnitude of the kth path, is the delay of the kth path, L is the number of paths, is the PRN code sequence, is the first hash value, To characterize the k The ideal transmission delay of the signal along each path.
4. The method according to claim 2, characterized in that The expression of the input signal is: ； in, is the input signal after spatial beamforming, is the weight, is the number of array elements, is the index of the array element, is the received signal received by the mth array element, is the receiving time difference of the mth array element.
5. The method according to claim 4, characterized in that The expression of the detail coefficient is: ； in, is the noise standard deviation, N is the signal length, is the detail coefficient at the jth scale, is the hard threshold.
6. The method according to claim 5, characterized in that The expression of the filtered signal is: ； in, is the filtered signal, is the magnitude of the kth path, is the delay of the kth path, and L is the number of paths.
7. The method according to claim 6, characterized in that The expression of the post-delay estimation is: ； in, For post-delay estimation.
8. The method according to claim 1, characterized in that The expression of underwater sound speed is: ； Where c(z) is the underwater sound speed at depth z, T is the temperature, S is the salinity, and z is the depth.
9. An electronic device, characterized in that: include: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method according to any one of claims 1 to 8.
10. A computer-readable storage medium storing a program executable by a processor, characterized in that: The processor-executable program is configured to perform the method according to any one of claims 1 to 8 when executed by the processor.