Underwater target detection method and system based on microwave surface vibration perception

Abstract

The present invention provides a method and system for underwater target detection based on microwave surface vibration sensing, comprising the following steps: Step S1: Using a carrier platform to drive a microwave transceiver to sense surface vibrations and extract surface vibration information generated by underwater target acoustic excitation; Step S2: Eliminating wave motion information and carrier platform motion information; Step S3: Analyzing the surface vibration information generated by underwater target acoustic excitation to locate the target water area; and Step S4: Detecting and locating the target and calculating its depth. The present invention proposes a method and system for underwater target detection based on microwave surface vibration sensing. The method utilizes a carrier platform equipped with a microwave transceiver to identify and locate underwater targets by extracting surface vibration information. This method addresses the difficulties encountered by existing underwater target detection methods in achieving maneuverable detection, long-distance detection, and accurate target positioning. It also overcomes the high power and bulk of existing active sonar systems and the heavy reliance of passive sonar on advanced materials and processes.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater target detection, and in particular to an underwater target detection method and system based on microwave water surface vibration perception. Background Art

[0002] Underwater target detection is an important common application requirement in underwater environment perception, marine resource monitoring and development, etc. Currently, underwater target detection mainly includes optical detection and acoustic detection.

[0003] Optical detection primarily uses imaging to identify targets, but light waves attenuate exponentially underwater, limiting detection range. Acoustic detection primarily exploits the excellent propagation and reflection properties of sound underwater, and includes both active and passive sonar. Active sonars are high in power and size, while passive sonars require pre-deployment, have weak low-frequency sensing, and have a limited detection range. Furthermore, existing sonar detection methods suffer from poor maneuverability and difficulty detecting depth information.

[0004] Optical underwater target detection: Light waves attenuate exponentially underwater, limiting detection range. Acoustic underwater target detection: Active sonars are high-power and bulky, while passive sonars require pre-deployment and have weak low-frequency sensing capabilities, resulting in a limited detection range. Furthermore, existing sonar detection methods suffer from challenges such as poor maneuverability and difficulty detecting depth information.

[0005] This invention proposes a method and system for underwater target detection based on microwave surface vibration sensing. This system utilizes a microwave transceiver and a carrier platform to rapidly detect and locate underwater targets. This system addresses the challenges of existing underwater target detection, including low-frequency detection, maneuverable detection, and long-range detection. It also addresses the high power and size of active sonar systems and the heavy reliance on advanced materials and processes for passive sonar systems. Summary of the Invention

[0006] In view of the defects in the prior art, the purpose of the present invention is to provide an underwater target detection method and system based on microwave water surface vibration perception.

[0007] According to the present invention, a method for underwater target detection based on microwave water surface vibration sensing is provided, comprising:

[0008] Step S1: Using the carrier platform to drive the microwave transceiver to sense water surface vibrations and extract water surface vibration information generated by underwater target hydroacoustic excitation;

[0009] Step S2: Eliminating wave motion information and carrier platform motion information;

[0010] Step S3: analyzing the water surface vibration information generated by the underwater target hydroacoustic excitation to locate the target water area;

[0011] Step S4: Detect and locate the target and calculate the depth.

[0012] Preferably, in step S1:

[0013] Microwave interferometry radar is used to sense the water surface vibration caused by underwater target hydroacoustic excitation. The carrier platform carries the microwave interferometry radar, with its transmitting antenna facing the target water surface. The microwave interferometry radar is controlled to transmit microwave signals to the water surface to be detected. The microwave transceiver obtains the baseband signal by transmitting and receiving microwave signals. For single-frequency continuous wave radar, methods including inverse tangent demodulation are used, and for frequency-modulated continuous wave radar, the interferometric phase evolution tracking method is used to invert the wave displacement information x(t) of the water surface:

[0014]

[0015] Where λ is the wavelength of the microwave signal, is the extracted interference phase evolution information, t is the time;

[0016] The microwave transceiver includes: a continuous wave microwave signal source, a power divider, a power amplifier, a mixer, a low-pass filter, a conditioning circuit, a transceiver antenna and a processor;

[0017] The continuous wave microwave signal source is used to transmit continuous wave microwave signals, which are divided into two paths through a power divider. One path is sent out by the transmitting antenna through a power amplifier, and the other path is input into a mixer to mix with the reflected signal received by the receiving antenna. The mixer is connected to a low-pass filter, and the mixed signal is input into the low-pass filter. The low-pass filter is connected to a conditioning circuit to finally generate a baseband signal for the microwave transceiver.

[0018] The transceiver antenna includes a transmitting antenna and a receiving antenna, and the number of the transmitting antenna and the receiving antenna is at least one.

[0019] Preferably, in step S2:

[0020] Based on the frequency range of sea surface waves, processing methods including high-pass filtering are used to eliminate ultra-low-frequency wave motion components in the water surface fluctuation displacement information;

[0021] By combining the motion information of the carrier platform with methods including vibration isolation gimbal and software algorithm filtering, the vibration interference component of the mobile body itself is eliminated to avoid the influence of the carrier platform's own vibration.

[0022] Preferably, in step S3:

[0023] Analyze the water surface vibration information generated by underwater target hydroacoustic excitation, and combine the position information of the carrier platform to locate the target water area and calculate the target depth. The specific operations are as follows:

[0024] The water surface vibration information δ(t) generated by underwater target hydroacoustic excitation is extracted. At the same time, the water surface micro-vibration information over a period of time is analyzed using methods including fast Fourier transform, short-time Fourier transform, and wavelet transform to obtain the frequency ω(t) of the water surface micro-vibration;

[0025] According to the frequency range and frequency variation law of the frequency characteristics ω′(t) of different underwater targets, the frequency ω(t) of the water surface micro-vibration is compared to find the target water area, and the underwater target category and the corresponding sound source sound pressure level range P0(dB) are determined based on prior knowledge.

[0026] Preferably, in step S4:

[0027] According to the relationship between water surface sound pressure and its excitation water surface vibration, the water surface sound pressure can be estimated:

[0028] P(ω,t)=ρvω(t)δ(t)

[0029] Where P(ω,t) represents the sound pressure near the water surface, ρ represents the density of water, v represents the speed of sound propagation underwater, ω represents the measured vibration frequency, ω(t) is the frequency of the water surface micro-vibration; δ(t) represents the water surface vibration information generated by underwater target acoustic excitation;

[0030] The target distance D is obtained based on the underwater target sound source sound pressure level range P0 (dB) and the spherical wave sound pressure attenuation law:

[0031]

[0032] According to the present invention, an underwater target detection system based on microwave water surface vibration sensing is provided, comprising:

[0033] Module M1: Uses a carrier platform to drive a microwave transceiver to sense water surface vibrations and extracts water surface vibration information generated by underwater target acoustic excitation.

[0034] Module M2: Eliminate wave motion information and carrier platform motion information;

[0035] Module M3: Analyzes the water surface vibration information generated by underwater target acoustic excitation and locates the target water area;

[0036] Module M4: Detect and locate the target and calculate the depth.

[0037] Preferably, in the module M1:

[0038] Microwave interferometry radar is used to sense the water surface vibration caused by underwater target hydroacoustic excitation. The carrier platform carries the microwave interferometry radar, with its transmitting antenna facing the target water surface. The microwave interferometry radar is controlled to transmit microwave signals to the water surface to be detected. The microwave transceiver obtains the baseband signal by transmitting and receiving microwave signals. For single-frequency continuous wave radar, methods including inverse tangent demodulation are used, and for frequency-modulated continuous wave radar, the interferometric phase evolution tracking method is used to invert the wave displacement information x(t) of the water surface:

[0039]

[0040] Where λ is the wavelength of the microwave signal, is the extracted interference phase evolution information, t is the time;

[0041] The microwave transceiver includes: a continuous wave microwave signal source, a power divider, a power amplifier, a mixer, a low-pass filter, a conditioning circuit, a transceiver antenna and a processor;

[0042] The continuous wave microwave signal source is used to transmit continuous wave microwave signals, which are divided into two paths through a power divider. One path is sent out by the transmitting antenna through a power amplifier, and the other path is input into a mixer to mix with the reflected signal received by the receiving antenna. The mixer is connected to a low-pass filter, and the mixed signal is input into the low-pass filter. The low-pass filter is connected to a conditioning circuit to finally generate a baseband signal for the microwave transceiver.

[0043] The transceiver antenna includes a transmitting antenna and a receiving antenna, and the number of the transmitting antenna and the receiving antenna is at least one.

[0044] Preferably, in the module M2:

[0045] Based on the frequency range of sea surface waves, processing methods including high-pass filtering are used to eliminate ultra-low-frequency wave motion components in the water surface fluctuation displacement information;

[0046] By combining the motion information of the carrier platform with methods including vibration isolation gimbal and software algorithm filtering, the vibration interference component of the mobile body itself is eliminated to avoid the influence of the carrier platform's own vibration.

[0047] Preferably, in the module M3:

[0048] Analyze the water surface vibration information generated by underwater target hydroacoustic excitation, and combine the position information of the carrier platform to locate the target water area and calculate the target depth. The specific operations are as follows:

[0049] The water surface vibration information δ(t) generated by underwater target hydroacoustic excitation is extracted. At the same time, the water surface micro-vibration information over a period of time is analyzed using methods including fast Fourier transform, short-time Fourier transform, and wavelet transform to obtain the frequency ω(t) of the water surface micro-vibration;

[0050] According to the frequency range and frequency variation law of the frequency characteristics ω′(t) of different underwater targets, the frequency ω(t) of the water surface micro-vibration is compared to find the target water area, and the underwater target category and the corresponding sound source sound pressure level range P0(dB) are determined based on prior knowledge.

[0051] Preferably, in the module M4:

[0052] According to the relationship between water surface sound pressure and its excitation water surface vibration, the water surface sound pressure can be estimated:

[0053] P(ω,t)=ρvω(t)δ(t)

[0054] Where P(ω,t) represents the sound pressure near the water surface, ρ represents the density of water, v represents the speed of sound propagation underwater, ω represents the measured vibration frequency, ω(t) is the frequency of the water surface micro-vibration; δ(t) represents the water surface vibration information generated by underwater target acoustic excitation;

[0055] The target distance D is obtained based on the underwater target sound source sound pressure level range P0 (dB) and the spherical wave sound pressure attenuation law:

[0056]

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] 1. This invention proposes a method and system for underwater target detection based on microwave surface vibration sensing. The system uses a carrier platform equipped with a microwave transceiver to extract surface vibration information to identify and locate underwater targets. This solves the problems of existing underwater target detection methods, such as difficulty in achieving mobile detection, long-distance detection, and accurate target positioning.

[0059] 2. The present invention overcomes the problems of existing active sonar systems, such as high power and volume, and passive sonar systems that rely heavily on advanced materials and processes;

[0060] 3. The present invention has strong low-frequency perception capability, a wide detection range, good maneuverability, and easy detection of depth information. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0062] Figure 1A schematic diagram of the system of the present invention;

[0063] Figure 2 is a flow chart of the method of the present invention;

[0064] Figure 3 This is a system block diagram of the present invention. DETAILED DESCRIPTION

[0065] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0066] Example 1:

[0067] According to the present invention, a method for underwater target detection based on microwave water surface vibration sensing is provided. Figure 1-Figure 3 As shown, including:

[0068] Step S1: Using the carrier platform to drive the microwave transceiver to sense water surface vibrations and extract water surface vibration information generated by underwater target hydroacoustic excitation;

[0069] Step S2: Eliminating wave motion information and carrier platform motion information;

[0070] Step S3: analyzing the water surface vibration information generated by the underwater target hydroacoustic excitation to locate the target water area;

[0071] Step S4: Detect and locate the target and calculate the depth.

[0072] Preferably, in step S1:

[0073] Microwave interferometry radar is used to sense the water surface vibration caused by underwater target hydroacoustic excitation. The carrier platform carries the microwave interferometry radar, with its transmitting antenna facing the target water surface. The microwave interferometry radar is controlled to transmit microwave signals to the water surface to be detected. The microwave transceiver obtains the baseband signal by transmitting and receiving microwave signals. For single-frequency continuous wave radar, methods including inverse tangent demodulation are used, and for frequency-modulated continuous wave radar, the interferometric phase evolution tracking method is used to invert the wave displacement information x(t) of the water surface:

[0074]

[0075] Where λ is the wavelength of the microwave signal, is the extracted interference phase evolution information, t is the time;

[0076] The microwave transceiver includes: a continuous wave microwave signal source, a power divider, a power amplifier, a mixer, a low-pass filter, a conditioning circuit, a transceiver antenna and a processor;

[0077] The continuous wave microwave signal source is used to transmit continuous wave microwave signals, which are divided into two paths through a power divider. One path is sent out by the transmitting antenna through a power amplifier, and the other path is input into a mixer to mix with the reflected signal received by the receiving antenna. The mixer is connected to a low-pass filter, and the mixed signal is input into the low-pass filter. The low-pass filter is connected to a conditioning circuit to finally generate a baseband signal for the microwave transceiver.

[0078] The transceiver antenna includes a transmitting antenna and a receiving antenna, and the number of the transmitting antenna and the receiving antenna is at least one.

[0079] Preferably, in step S2:

[0080] Based on the frequency range of sea surface waves, processing methods including high-pass filtering are used to eliminate ultra-low-frequency wave motion components in the water surface fluctuation displacement information;

[0081] By combining the motion information of the carrier platform with methods including vibration isolation gimbal and software algorithm filtering, the vibration interference component of the mobile body itself is eliminated to avoid the influence of the carrier platform's own vibration.

[0082] Preferably, in step S3:

[0083] Analyze the water surface vibration information generated by underwater target hydroacoustic excitation, and combine the position information of the carrier platform to locate the target water area and calculate the target depth. The specific operations are as follows:

[0084] The water surface vibration information δ(t) generated by underwater target hydroacoustic excitation is extracted. At the same time, the water surface micro-vibration information over a period of time is analyzed using methods including fast Fourier transform, short-time Fourier transform, and wavelet transform to obtain the frequency ω(t) of the water surface micro-vibration;

[0085] According to the frequency range and frequency variation law of the frequency characteristics ω′(t) of different underwater targets, the frequency ω(t) of the water surface micro-vibration is compared to find the target water area, and the underwater target category and the corresponding sound source sound pressure level range P0(dB) are determined based on prior knowledge.

[0086] Preferably, in step S4:

[0087] According to the relationship between water surface sound pressure and its excitation water surface vibration, the water surface sound pressure can be estimated:

[0088] P(ω,t)=ρvω(t)δ(t)

[0089] Where P(ω,t) represents the sound pressure near the water surface, ρ represents the density of water, v represents the speed of sound propagation underwater, ω represents the measured vibration frequency, ω(t) is the frequency of the water surface micro-vibration; δ(t) represents the water surface vibration information generated by underwater target acoustic excitation;

[0090] The target distance D is obtained based on the underwater target sound source sound pressure level range P0 (dB) and the spherical wave sound pressure attenuation law:

[0091]

[0092] Example 2:

[0093] Example 2 is a preferred example of Example 1 and is used to illustrate the present invention in more detail.

[0094] Those skilled in the art may understand the underwater target detection method based on microwave water surface vibration perception provided by the present invention as a specific implementation of the underwater target detection system based on microwave water surface vibration perception, that is, the underwater target detection system based on microwave water surface vibration perception may be realized by executing the step process of the underwater target detection method based on microwave water surface vibration perception.

[0095] According to the present invention, an underwater target detection system based on microwave water surface vibration sensing is provided, comprising:

[0096] Module M1: Uses a carrier platform to drive a microwave transceiver to sense water surface vibrations and extracts water surface vibration information generated by underwater target acoustic excitation.

[0097] Module M2: Eliminate wave motion information and carrier platform motion information;

[0098] Module M3: Analyzes the water surface vibration information generated by underwater target acoustic excitation and locates the target water area;

[0099] Module M4: Detect and locate the target and calculate the depth.

[0100] Preferably, in the module M1:

[0101] Microwave interferometry radar is used to sense the water surface vibration caused by underwater target hydroacoustic excitation. The carrier platform carries the microwave interferometry radar, with its transmitting antenna facing the target water surface. The microwave interferometry radar is controlled to transmit microwave signals to the water surface to be detected. The microwave transceiver obtains the baseband signal by transmitting and receiving microwave signals. The single-frequency continuous wave radar uses methods including inverse tangent demodulation. For the frequency modulated continuous wave radar, the interferometric phase evolution tracking method is used to invert the wave displacement information x(t) of the water surface:

[0102]

[0103] Where λ is the wavelength of the microwave signal, is the extracted interference phase evolution information, t is the time;

[0104] The microwave transceiver includes: a continuous wave microwave signal source, a power divider, a power amplifier, a mixer, a low-pass filter, a conditioning circuit, a transceiver antenna and a processor;

[0105] The continuous wave microwave signal source is used to transmit continuous wave microwave signals, which are divided into two paths through a power divider. One path is sent out by the transmitting antenna through a power amplifier, and the other path is input into a mixer to mix with the reflected signal received by the receiving antenna. The mixer is connected to a low-pass filter, and the mixed signal is input into the low-pass filter. The low-pass filter is connected to a conditioning circuit to finally generate a baseband signal for the microwave transceiver.

[0106] The transceiver antenna includes a transmitting antenna and a receiving antenna, and the number of the transmitting antenna and the receiving antenna is at least one.

[0107] Preferably, in the module M2:

[0108] Based on the frequency range of sea surface waves, processing methods including high-pass filtering are used to eliminate ultra-low-frequency wave motion components in the water surface fluctuation displacement information;

[0109] By combining the motion information of the carrier platform with methods including vibration isolation gimbal and software algorithm filtering, the vibration interference component of the mobile body itself is eliminated to avoid the influence of the carrier platform's own vibration.

[0110] Preferably, in the module M3:

[0111] Analyze the water surface vibration information generated by underwater target hydroacoustic excitation, and combine the position information of the carrier platform to locate the target water area and calculate the target depth. The specific operations are as follows:

[0112] The water surface vibration information δ(t) generated by underwater target hydroacoustic excitation is extracted. At the same time, the water surface micro-vibration information over a period of time is analyzed using methods including fast Fourier transform, short-time Fourier transform, and wavelet transform to obtain the frequency ω(t) of the water surface micro-vibration;

[0113] According to the frequency range and frequency variation law of the frequency characteristics ω′(t) of different underwater targets, the frequency ω(t) of the water surface micro-vibration is compared to find the target water area, and the underwater target category and the corresponding sound source sound pressure level range P0(dB) are determined based on prior knowledge.

[0114] Preferably, in the module M4:

[0115] According to the relationship between water surface sound pressure and its excitation water surface vibration, the water surface sound pressure can be estimated:

[0116] P(ω,t)=ρvω(t)δ(t)

[0117] Where P(ω,t) represents the sound pressure near the water surface, ρ represents the density of water, v represents the speed of sound propagation underwater, ω represents the measured vibration frequency, ω(t) is the frequency of the water surface micro-vibration; δ(t) represents the water surface vibration information generated by underwater target acoustic excitation;

[0118] The target distance D is obtained based on the underwater target sound source sound pressure level range P0 (dB) and the spherical wave sound pressure attenuation law:

[0119]

[0120] Example 3:

[0121] Example 3 is a preferred example of Example 1 and is used to illustrate the present invention in more detail.

[0122] This paper addresses the challenges and shortcomings of existing underwater target detection by proposing a method and system for underwater target detection based on microwave surface vibration sensing. First, a microwave transceiver carried by a carrier platform senses water surface fluctuations. By extracting the surface vibration information generated by underwater target acoustic excitation and combining it with the target's acoustic characteristics, target detection and location are performed.

[0123] The present invention relates to an underwater target detection method based on microwave water surface vibration perception:

[0124] Step 1: Using a carrier platform including an aircraft to drive a microwave transceiver to sense water surface vibrations and extract water surface vibration information generated by underwater target acoustic excitation;

[0125] Step 2: Analyze the water surface vibration information generated by underwater target acoustic excitation, locate the target water area, and perform target detection and positioning.

[0126] The method for the microwave transceiver to sense water surface vibration in step 1 is as follows:

[0127] Step 1.1: Using a microwave transceiver, measure water surface fluctuation information including water surface vibration information generated by underwater target acoustic excitation;

[0128] Step 1.2: Eliminate the wave motion component in the water surface fluctuation information;

[0129] Ultra-low frequency wave motion components are eliminated through elimination methods including high-pass filtering.

[0130] Step 1.3 eliminates the interference information of the maneuvering body itself and finally extracts the water surface vibration information generated by the underwater target hydroacoustic excitation.

[0131] The vibration interference component of the carrier platform itself is eliminated through methods including vibration isolation gimbal and software algorithm filtering.

[0132] The target water area positioning and target depth calculation method in step 2 is:

[0133] Step 2.1: Based on the prior knowledge of the underwater acoustic characteristics of the target to be detected, the matching vibrating water area is detected to achieve the target water area positioning and underwater target category identification.

[0134] The underwater acoustic characteristics of the target include frequency range, frequency variation characteristics and sound pressure level of the sound source.

[0135] Step 2.2: Calculate the target depth based on the attenuation relationship between underwater sound pressure and propagation distance.

[0136] P(ω,t)=ρvω(t)δ(t)

[0137] Where P(ω,t) represents the sound pressure near the water surface, ρ represents the water density, ω represents the measured vibration frequency, v represents the speed of sound propagation underwater, and δ(t) represents the extracted water surface vibration information generated by underwater target acoustic excitation. Based on the underwater target sound pressure level range P0 (dB) and the spherical wave sound pressure attenuation law, the target distance D can be obtained:

[0138]

[0139] The present invention relates to an underwater target detection system based on microwave water surface vibration perception, comprising: a carrier platform, a microwave transceiver, a water surface vibration information extraction module, a target detection and identification module and a memory.

[0140] The carrier platform is used to carry millimeter-wave radar for large-scale maneuverable surface measurements. The microwave transceiver transmits and receives continuous-wave microwave signals and generates the baseband signal for the microwave transceiver. The surface vibration information extraction module collects and processes the microwave transceiver baseband signal into time-domain information of the water surface's wave displacement, suppresses the microwave transceiver's self-vibration generated by the carrier platform's operation, and ultimately extracts surface vibration information generated by underwater target hydroacoustic excitation. The target detection and identification module converts surface vibration information into underwater target detection and positioning information. A memory is used to store information including surface vibration information, underwater target detection and identification information, and positioning information.

[0141] The microwave transceiver includes a continuous-wave microwave signal source, a power divider, a power amplifier, a mixer, a low-pass filter, a conditioning circuit, a transceiver antenna, and a processor. The continuous-wave microwave signal source transmits a continuous-wave microwave signal, which is split into two paths by the power divider: one path is transmitted by the power amplifier and then emitted by the transmitting antenna, while the other path is input into a mixer for mixing with the reflected signal received by the receiving antenna. The mixer is connected to a low-pass filter, which then inputs the mixed signal into the low-pass filter, which is then connected to the conditioning circuit to ultimately generate the baseband signal for the microwave transceiver.

[0142] The transceiver antenna includes a transmitting antenna and a receiving antenna, and the number of the transmitting antenna and the receiving antenna is at least one.

[0143] Example 4:

[0144] Example 4 is a preferred example of Example 1 and is used to illustrate the present invention in more detail.

[0145] like Figure 1 The figure shows a schematic diagram of an underwater target detection method and system based on microwave surface vibration sensing. Using a carrier platform equipped with a microwave transceiver, underwater target identification and positioning are performed by extracting surface vibration information generated by underwater target hydroacoustic excitation.

[0146] like Figure 2 FIG. 1 is a flow chart of an underwater target detection method based on microwave water surface vibration sensing according to the present invention, comprising the following steps:

[0147] Step 1: Use microwave interferometric radar to sense the water surface vibration generated by underwater target acoustic excitation. The specific operations are as follows:

[0148] Step 1.1: The carrier platform carries a microwave interferometer radar, with its transmitting antenna facing the target water surface. The microwave interferometer radar is controlled to transmit microwave signals into the water surface to be detected. The microwave transceiver obtains the baseband signal by transmitting and receiving the microwave signals. For single-frequency continuous wave radar, methods including arc tangent demodulation are used. For frequency modulated continuous wave (FMCW) radar, the interferometric phase evolution tracking method can be used to invert the wave displacement information of the water surface:

[0149]

[0150] Where λ is the wavelength of the microwave signal, is the extracted interference phase evolution information.

[0151] In step 1.2, based on the frequency range of sea surface waves, processing methods including high-pass filtering are used to eliminate the ultra-low-frequency wave motion components in the water surface fluctuation displacement information.

[0152] In step 1.3, the vibration interference component of the mobile body itself is eliminated by combining the motion information of the carrier platform with methods including vibration isolation gimbal and software algorithm filtering to avoid the influence of the carrier platform's own vibration.

[0153] Step 2: Analyze the water surface vibration information generated by underwater target acoustic excitation, locate the target water area and calculate the target depth based on the position information of the carrier platform. The specific operations are as follows:

[0154] In step 2.1, the water surface vibration information δ(t) generated by the underwater target hydroacoustic excitation is extracted, and the water surface micro-vibration information over a period of time is analyzed using methods including fast Fourier transform, short-time Fourier transform, and wavelet transform to obtain the frequency ω(t) of the water surface micro-vibration.

[0155] In step 2.2, based on the frequency range and frequency variation law of the frequency characteristics ω′(t) of different underwater targets, the frequency ω(t) of the water surface micro-vibration is compared to find the target water area. The underwater target category and the corresponding sound source sound pressure level range P0 (dB) are determined based on prior knowledge.

[0156] Step 2.3, estimate the water surface sound pressure based on the relationship between the water surface sound pressure and the water surface vibration it excites:

[0157] P(ω,t)=ρvω(t)δ(t)

[0158] Where P(ω,t) represents the sound pressure near the water surface, ρ represents the water density, ω represents the measured vibration frequency, v represents the speed of sound propagation underwater, and δ(t) represents the water surface vibration information generated by underwater target acoustic excitation. Based on the underwater target sound source sound pressure level range P0 (dB) and the spherical wave sound pressure attenuation law, the target distance D can be obtained:

[0159]

[0160] like Figure 3As shown, the present invention relates to an underwater target detection system based on microwave surface vibration perception, comprising: a carrier platform, a microwave transceiver, a surface vibration information extraction module, a target detection and identification module, and a memory. The carrier platform is used to carry a millimeter-wave radar for large-scale maneuvering measurement of the water surface; the microwave transceiver is used to transmit and receive continuous-wave microwave signals and generate baseband signals of the microwave transceiver; the surface vibration information extraction module is used to collect and process the microwave transceiver baseband signals into time-domain information of the wave displacement of the water surface, and suppress the self-vibration of the microwave transceiver generated by the operation of the carrier platform, and finally extract the surface vibration information of the underwater target hydroacoustic excitation. The target detection and identification module is used to invert the surface vibration information into underwater target detection and target position positioning information. The memory is used to store information including surface vibration information, underwater target detection and identification information, and positioning information.

[0161] The microwave transceiver includes a continuous-wave microwave signal source, a power divider, a power amplifier, a mixer, a low-pass filter, a conditioning circuit, a transceiver antenna, and a processor. The continuous-wave microwave signal source transmits a continuous-wave microwave signal, which is split into two paths by the power divider: one path is transmitted by the power amplifier and then emitted by the transmitting antenna, while the other path is input into a mixer for mixing with the reflected signal received by the receiving antenna. The mixer is connected to a low-pass filter, which then inputs the mixed signal into the low-pass filter, which is then connected to the conditioning circuit to ultimately generate the baseband signal for the microwave transceiver.

[0162] The transceiver antenna includes a transmitting antenna and a receiving antenna, and the number of the transmitting antenna and the receiving antenna is at least one.

[0163] Those skilled in the art will appreciate that, in addition to implementing the system, device, and various modules provided by the present invention in purely computer-readable program code, it is entirely possible to implement the same program in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, embedded microcontrollers, and the like by logically programming the method steps. Therefore, the system, device, and various modules provided by the present invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; the modules for implementing various functions can also be considered both software programs for implementing the method and structures within the hardware component.

[0164] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A method for underwater target detection based on microwave surface vibration sensing, characterized in that: include: Step S1: Using the carrier platform to drive the microwave transceiver to sense water surface vibrations and extract water surface vibration information generated by underwater target hydroacoustic excitation; Step S2: Eliminating wave motion information and carrier platform motion information; Step S3: analyzing the water surface vibration information generated by the underwater target hydroacoustic excitation to locate the target water area; Step S4: Detect and locate the target and calculate the depth; In step S1: Microwave interferometry radar is used to sense the water surface vibration caused by underwater target hydroacoustic excitation. The carrier platform carries the microwave interferometry radar, with its transmitting antenna facing the target water surface. The microwave interferometry radar is controlled to transmit microwave signals to the water surface to be detected. The microwave transceiver obtains the baseband signal by transmitting and receiving microwave signals. For single-frequency continuous wave radar, methods including inverse tangent demodulation are used, and for frequency-modulated continuous wave radar, the interferometric phase evolution tracking method is used to invert the wave displacement information x(t) of the water surface: Where λ is the wavelength of the microwave signal, is the extracted interference phase evolution information, t is the time; In step S4: According to the relationship between water surface sound pressure and its excitation water surface vibration, the water surface sound pressure can be estimated: P(ω,t)=ρvω(t)δ(t) Where P(ω,t) represents the sound pressure near the water surface, ρ represents the density of water, v represents the speed of sound propagation underwater, ω represents the measured vibration frequency, ω(t) is the frequency of the water surface micro-vibration; δ(t) represents the water surface vibration information generated by underwater target acoustic excitation; The target distance D is obtained based on the underwater target sound source sound pressure level range P0 (dB) and the spherical wave sound pressure attenuation law:

2. The underwater target detection method based on microwave water surface vibration perception according to claim 1 is characterized in that: In step S2: Based on the frequency range of sea surface waves, processing methods including high-pass filtering are used to eliminate ultra-low-frequency wave motion components in the water surface fluctuation displacement information; By combining the motion information of the carrier platform with methods including vibration isolation gimbal and software algorithm filtering, the vibration interference component of the mobile body itself is eliminated to avoid the influence of the carrier platform's own vibration.

3. The underwater target detection method based on microwave water surface vibration perception according to claim 1 is characterized in that: In step S3: Analyze the water surface vibration information generated by underwater target hydroacoustic excitation, and combine the position information of the carrier platform to locate the target water area and calculate the target depth. The specific operations are as follows: The water surface vibration information δ(t) generated by underwater target hydroacoustic excitation is extracted. At the same time, the water surface micro-vibration information over a period of time is analyzed using methods including fast Fourier transform, short-time Fourier transform, and wavelet transform to obtain the frequency ω(t) of the water surface micro-vibration; According to the frequency range and frequency variation law of the frequency characteristics ω′(t) of different underwater targets, the frequency ω(t) of the water surface micro-vibration is compared to find the target water area, and the underwater target category and the corresponding sound source sound pressure level range P0(dB) are determined based on prior knowledge.

4. An underwater target detection system based on microwave water surface vibration sensing, characterized in that: include: Module M1: Uses a carrier platform to drive a microwave transceiver to sense water surface vibrations and extracts water surface vibration information generated by underwater target acoustic excitation. Module M2: Eliminate wave motion information and carrier platform motion information; Module M3: Analyzes the water surface vibration information generated by underwater target acoustic excitation and locates the target water area; Module M4: detects and locates the target and calculates the depth; In the module M1: Microwave interferometry radar is used to sense the water surface vibration caused by underwater target hydroacoustic excitation. The carrier platform carries the microwave interferometry radar, with its transmitting antenna facing the target water surface. The microwave interferometry radar is controlled to transmit microwave signals to the water surface to be detected. The microwave transceiver obtains the baseband signal by transmitting and receiving microwave signals. For single-frequency continuous wave radar, methods including inverse tangent demodulation are used, and for frequency-modulated continuous wave radar, the interferometric phase evolution tracking method is used to invert the wave displacement information x(t) of the water surface: Where λ is the wavelength of the microwave signal, is the extracted interference phase evolution information, t is the time; The microwave transceiver includes: a continuous wave microwave signal source, a power divider, a power amplifier, a mixer, a low-pass filter, a conditioning circuit, a transceiver antenna and a processor; The continuous wave microwave signal source is used to transmit continuous wave microwave signals, which are divided into two paths through a power divider. One path is sent out by the transmitting antenna through a power amplifier, and the other path is input into a mixer to mix with the reflected signal received by the receiving antenna. The mixer is connected to a low-pass filter, and the mixed signal is input into the low-pass filter. The low-pass filter is connected to a conditioning circuit to finally generate a baseband signal for the microwave transceiver. The transceiver antenna includes a transmitting antenna and a receiving antenna, and the number of the transmitting antenna and the receiving antenna is at least one; In the module M4: According to the relationship between water surface sound pressure and its excitation water surface vibration, the water surface sound pressure can be estimated: P(ω,t)=ρvω(t)δ(t) Where P(ω,t) represents the sound pressure near the water surface, ρ represents the density of water, v represents the speed of sound propagation underwater, ω represents the measured vibration frequency, ω(t) is the frequency of the water surface micro-vibration; δ(t) represents the water surface vibration information generated by underwater target acoustic excitation; The target distance D is obtained based on the underwater target sound source sound pressure level range P0 (dB) and the spherical wave sound pressure attenuation law:

5. The underwater target detection system based on microwave water surface vibration sensing according to claim 4 is characterized in that: In the module M2: Based on the frequency range of sea surface waves, processing methods including high-pass filtering are used to eliminate ultra-low-frequency wave motion components in the water surface fluctuation displacement information; By combining the motion information of the carrier platform with methods including vibration isolation gimbal and software algorithm filtering, the vibration interference component of the mobile body itself is eliminated to avoid the influence of the carrier platform's own vibration.

6. The underwater target detection system based on microwave water surface vibration sensing according to claim 4 is characterized in that: In the module M3: Analyze the water surface vibration information generated by underwater target hydroacoustic excitation, and combine the position information of the carrier platform to locate the target water area and calculate the target depth. The specific operations are as follows: The water surface vibration information δ(t) generated by underwater target hydroacoustic excitation is extracted. At the same time, the water surface micro-vibration information over a period of time is analyzed using methods including fast Fourier transform, short-time Fourier transform, and wavelet transform to obtain the frequency ω(t) of the water surface micro-vibration; According to the frequency range and frequency variation law of the frequency characteristics ω′(t) of different underwater targets, the frequency ω(t) of the water surface micro-vibration is compared to find the target water area, and the underwater target category and the corresponding sound source sound pressure level range P0(dB) are determined based on prior knowledge.

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