An all-link low physical feature deep sea communication system and method thereof

Abstract

A full-link low-physical-feature deep-sea communication system and method thereof; the system integrates a pressure-driven ion energy power generation unit, a dual-resonance magnetic coupling high-speed communication unit, a magneto-electro-mechanical antenna long-distance communication unit, a low-physical-feature suspension platform, an active anti-silt unit and a comprehensive energy management unit. The pressure-driven ion energy power generation unit utilizes the deep-sea hydrostatic pressure to drive the ion transmembrane migration to generate electric energy; the dual-resonance magnetic coupling antenna realizes 1 Mbps to 30 Mbps adaptive covert communication; the magneto-electro-mechanical antenna is multiplexed with the power generation unit electrode network, uses the electrode accumulated charge as part of the transmission energy source and has a counter electromotive force recovery function, to realize kilometer-level communication with low power consumption; the anti-silt unit shares the cantilever beam with the antenna, the vibration frequency is lower than the environmental noise and is used as a signal wake-up. The system has a built-in intelligent switching controller, which automatically selects the best antenna and working mode according to the channel quality, and uniformly executes spread spectrum camouflage on the transmission signal, so that each communication link has physical layer undetectability.

Description

Technical Field

[0001] This invention relates to the fields of deep-sea communication and energy technology, and in particular to a deep-sea communication system and method with low physical characteristics across the entire link. Background Technology

[0002] The long-term autonomous operation of deep-sea equipment faces two fundamental bottlenecks: energy supply and covert communication. Existing technological approaches have irreconcilable contradictions in both of these aspects.

[0003] In terms of energy supply, current deep-sea equipment mainly relies on high-energy-density primary batteries or secondary batteries that require periodic recycling and recharging. The former is limited by total energy and cannot support deployment cycles measured in years; the latter requires expensive and high-risk underwater recovery operations, resulting in high operation and maintenance costs. Utilizing marine environmental energy for in-situ power generation is an ideal alternative, but known solutions each have their drawbacks. Ocean current or turbine power generation is difficult to start at typical deep-sea current velocities (0.1-0.5 m / s), and multi-directional flows require complex yaw mechanisms; the rotating dynamic seal is prone to leakage and failure under 10 MPa pressure. Thermoelectric power generation is limited by the vertical temperature difference in the deep sea (usually less than 25°C), resulting in low conversion efficiency and a large system size. Wave energy generation relies entirely on sea surface fluctuations and is not suitable for the deep-sea environment. Although salinity gradient power generation based on reverse electrodialysis or pressure-delayed osmosis has been widely studied, it relies on externally pumped solutions to maintain the concentration gradient, resulting in high parasitic energy consumption, and the mechanical strength of existing ion exchange membranes can only withstand 0.5-2 MPa, far below the hydrostatic pressure of the deep sea.

[0004] In terms of covert communication, underwater wireless communication mainly relies on three methods: acoustic, optical, and electromagnetic waves. However, all three have inherent limitations in terms of concealment. Sound waves propagate easily in water, and passive sonar can detect and locate sound sources from several kilometers away. Even with low probability of intercept (POC) techniques such as spread spectrum or frequency hopping, sound signals cannot be completely hidden from ocean background noise. Optical signals have good directionality, but high-power light sources can be detected by optical sensors at long distances underwater, and light signals can leak into the air through scattering at the water surface, posing a risk of detection by satellites or drones. Magnetic induction communication utilizes the near-field attenuation characteristics of magnetic fields in seawater (field strength decreases with the cube of distance) and does not generate sound radiation, possessing a natural concealment advantage. However, most existing magnetic induction communication systems do not systematically consider the identifiability of signal waveforms, and their modulated signals can still be detected by magnetic anomaly detectors or high-order spectral analysis. In particular, when using direct sequence spread spectrum, the periodic structure of the spreading code produces cyclic stationary characteristics, which can become a vulnerability exploited by eavesdroppers over long-term observation.

[0005] Furthermore, deep-sea engineering deployments also face practical problems such as seabed silt burial and high-pressure seal failure. Traditional bottom-mounted equipment is easily covered by several meters of silt, leading to heat dissipation failure, mechanical jamming, and seal damage. Meanwhile, the high-pressure environment of the deep sea poses a severe challenge to any form of rotating dynamic seal; the reliable lifespan of existing mechanical seals is often less than one year. Ultra-low frequency (ULF) and very low frequency (VLF) communications are also hampered by the trade-off between antenna size and radiation efficiency. While magneto-electro-mechanical antennas developed in recent years offer a new approach, they have not yet been integrated with deep-sea in-situ energy and system-level signal camouflage solutions.

[0006] In summary, existing technologies are insufficient to simultaneously meet the multiple requirements of long-term energy self-sufficiency in the deep sea, highly covert communication, maintenance-free deployment, and effective low-frequency radiation. A novel solution that can systematically overcome these bottlenecks is urgently needed. Summary of the Invention

[0007] The technical problem to be solved by this invention is to provide a deep-sea communication system and method with low physical characteristics across the entire link. This system can utilize the hydrostatic pressure of deep sea water to drive ion migration and generate continuous electrical energy, realize high-speed communication with dual resonant magnetic coupling and long-distance communication with magneto-electro-mechanical antennas, and make the radiated magnetic field and background magnetic noise statistically indistinguishable through active signal camouflage. At the same time, it adopts a fully non-magnetic levitation platform to suppress magnetic anomalies and acoustic radiation, and integrates functions such as energy, communication, camouflage, and anti-siltation into one, supporting maintenance-free deployment.

[0008] To solve the above-mentioned technical problems, the technical solution of the present invention is: a deep-sea communication system and method with low physical characteristics across the entire link, the innovation of which lies in: comprising the following modules: Module A: Pressure-driven ion energy generation unit The module comprises a sealed cavity made of titanium alloy TC4, with a wall thickness determined by finite element analysis to be safe for withstanding hydrostatic pressure exceeding 10 MPa. The internal volume ranges from 0.5 L to 5 L, filled with a 6M NaCl electrolyte solution. An ion-selective membrane assembly is mounted on the cavity wall. This membrane employs a gradient multilayer composite structure, consisting, from bottom to top, of a high-strength porous support layer made of PTFE nanofibers, a cross-linked polymer / nanoparticle intermediate transition layer, and a functional separation layer formed by the self-assembly of metal-organic framework UiO-66-NH2 nanocrystals and graphene oxide nanosheets through vacuum filtration. The thickness of the functional layer is controlled at 500 nm, and the channel size is in the range of 0.3-1.0 nm. The cavity is equipped with a magnetically coupled piston pressure transmission mechanism to transfer external hydrostatic pressure to the internal solution. The internal electrodes are platinum-plated titanium mesh, and the external electrodes are titanium mesh. Both electrodes are led out to an external circuit via a watertight connector, and the energy storage battery is charged after MPPT boost conversion.

[0009] Module B: Dual-resonant magnetically coupled stealth communication unit The antenna section of this unit is a triaxial orthogonal loop coil assembly, consisting of three loop coils with identical geometric parameters mounted perpendicularly to each other on a PEEK frame. Each coil is wound with Litz wire, consisting of 60 to 100 strands of mutually insulated fine copper wire with a diameter of 0.04 mm to 0.10 mm, with 35 to 40 turns and a coil diameter of 100 mm to 200 mm. Each coil is connected in parallel to an adjustable capacitor array, with a total tuning capacitance ranging from 5 pF to 2000 pF. A microcontroller-controlled switching network switches the capacitors to achieve dual-resonant matching at both the transmitting and receiving ends.

[0010] The modulation and demodulation employs a single-carrier QPSK modulation and frequency-domain equalization (SC-FDE) scheme, and switches between QPSK and BPSK in stages according to the real-time channel quality: QPSK modulation with a code rate of 1 / 2 is used when the signal-to-noise ratio (SNR) is higher than 10dB; BPSK modulation with a code rate of 1 / 2 is used when the SNR is between 8dB and 10dB; and BPSK modulation with a code rate of 1 / 4 (repeated coding) is used when the SNR is lower than 8dB. The data rate is adaptive from 1Mbps to 30Mbps. The three-axis coils are each controlled by an independent drive circuit, and magnetic dipole moments in arbitrary directions are synthesized in space by adjusting the amplitude and phase of the current of each axis.

[0011] Module C: Signal Disguise Submodule This module employs a spread spectrum modulation scheme based on a shared dictionary. A large-capacity waveform dictionary is pre-installed at both the transmitter and authorized receiver, containing no fewer than 216 spread spectrum waveforms with varying chip lengths and chip rates. The chip rates of these waveforms are randomly distributed within the range of 1kHz to 50kHz, and the cross-correlation coefficients between the waveforms are close to zero. The bit stream to be transmitted is encrypted and grouped into fixed-length blocks. A key-driven pseudo-random number generator selects one or more waveforms from the dictionary to map this group of information. The selected waveforms undergo spectral shaping using a digital filter, ensuring that the fitting error between their power spectral density and the deep-sea magnetic noise spectrum within the target frequency band is controlled to within 10%. At the receiver, matched filtering is used to perform correlation operations with all waveforms in the dictionary, and the information is recovered by inverse mapping based on the peak positions. An adaptive power controller adjusts the transmit power based on channel quality feedback from the receiver.

[0012] Module D: Magneto-electro-mechanical antenna supplementary communication unit The unit contains at least one set of magneto-electro-mechanical antenna arrays. Each antenna element is composed of a layered heterostructure bonded to a magnetostrictive layer (FeGa alloy) and a piezoelectric layer (PZT ceramic). The element size is much smaller than the wavelength of the electromagnetic wave corresponding to the radiation frequency. Under electrical excitation, it generates mechanical resonance. The radiation frequency is determined by the mechanical size, and a flexible configuration from hundreds of hertz to tens of kilohertz can be achieved.

[0013] This unit and the PSIC power generation unit form a multiplexed structure with their respective electrode networks. The internal electrodes of the PSIC, made of platinum-plated titanium mesh, are divided into several independent zones, each corresponding to the location of an ME antenna unit. Each zone's electrodes are connected to the PSIC power generation circuit via a programmable switch matrix composed of solid-state relay arrays for ion current collection. In transmission mode, the circuit drives the ME antenna with a high-voltage pulse, while in reception mode, it serves as the input of a low-noise preamplifier. In transmission mode, the electrode zone switches from the power generation circuit to a pulse forming network, instantaneously releasing the charge accumulated on the electrode surface due to ion migration to the piezoelectric layer of the ME antenna, generating a high-voltage pulse (peak voltage 50-200V) to excite the PZT layer to vibrate. After the pulse excitation ends, the back electromotive force generated by the mechanical vibration recovery of the PZT layer is recharged back to the energy storage battery through a rectifier bridge + DC / DC boost converter energy recovery circuit, achieving a recovery efficiency of 15%-30%. This "power generation with electricity, and electricity-assisted generation" design ensures that part of the instantaneous energy emitted by the antenna comes from the energy stored in the electrode capacitors, reducing the net power consumption extracted from the battery.

[0014] Multiple ME elements can be arranged in 2×2 to 5×5 arrays, with each element's excitation phase independently adjustable to achieve spatial synthesis of the radiated magnetic field and beamforming. This element serves as a mid-range communication channel with a coverage area of ​​1-5 kilometers, used for data relay and broadcast control in turbid waters or when node spacing is large. Multiple ME antenna nodes form a mid-range relay network, enabling hop-by-hop data forwarding. For long-distance communication exceeding 5 kilometers, the system utilizes metamaterial-enhanced magnetic induction technology to achieve a wide-area backbone channel with node spacing of 20-50 kilometers, extending coverage through multi-hop relay using ME antennas.

[0015] Module E: Low Physical Characteristics Suspension Platform Unit The main buoy is made of glass microspheres / epoxy composite foam, a material with mature applications in deep-sea engineering. It has a density of 0.5-0.7 g / cm³ and a compressive strength of 40-70 MPa, meeting the requirements for deep-sea service at depths of 1000 meters. The rigid frame is integrally machined from PEEK engineering plastic, a material known for its hydrolysis resistance, dimensional stability, and excellent electrical insulation properties. It maintains structural integrity during long-term immersion tests in a simulated 10 MPa deep-sea environment. The mooring system consists of a buoyancy carrier and a counterweight. The buoyancy carrier provides net buoyancy, while the counterweight is suspended below the device via short Dyneema® SK78 cables (10m to 30m in length) to provide attitude damping. The entire device utilizes a permanent density gradient existing at depths of 500 to 1000 meters to achieve passive vertical stability, independent of seabed anchor points.

[0016] Module F: Active anti-fogging and self-cleaning unit This unit uses a miniature eccentric motor as the excitation source, with a power of 0.1-1W. It achieves stepless frequency conversion from 1-10Hz by adjusting the voltage, with the dominant vibration frequency set at 3Hz. This unit shares a cantilever beam mechanical structure with the ME antenna system: the eccentric motor of the anti-siltation system is mounted on a central base, with six PEEK cantilever beams radially distributed from the base. The free ends abut against the inner wall of the outer shell, and the ME antenna array elements are attached to the surface of the cantilever beams (closer to the fixed ends). This allows the cantilever beams to simultaneously bear the low-frequency displacement of the anti-siltation vibration at 3Hz and the high-frequency mechanical strain of the ME antenna at hundreds of Hz to several kHz. These two modes do not interfere with each other due to the frequency difference of more than two orders of magnitude. The cantilever beam parameters are designed (100mm long, 15mm wide, 3mm thick) so that its first natural frequency (170-210Hz in water) is much higher than the excitation operating frequency, and the system operates in the quasi-static stiffness-dominated region.

[0017] Four levels of suppression measures are implemented along the vibration transmission path: a silicone rubber gasket is embedded between the exciter and the frame; a high-loss polyurethane elastomer with a vibration isolation efficiency of 70% is placed between the frame and the outer shell; a thin layer of localized resonant acoustic metamaterial is applied to the inner side of the outer shell to reduce the radiation efficiency to below 0.1; and a polyurethane / hollow glass microsphere composite damping layer is coated on the outer side of the outer shell to further absorb energy. The outer shell surface is coated with a super-dual-hydrophobic coating of fluorinated carbon nanotubes with a contact angle greater than 150°. In standby mode, the anti-sludge system vibrates at a low frequency of 3Hz, while at least one electrode zone is suspended and monitors the ambient magnetic field signal through a high-impedance detection circuit. When the detected signal strength exceeds a preset threshold, an interrupt signal is output to wake up the main controller—the anti-sludge vibration itself also serves as the signal sensing front end.

[0018] Module G: Integrated Energy Management and Central Control Unit The central controller employs an ultra-low-power microcontroller, integrating a hardware encryption engine (supporting AES-128), a real-time clock, and a multi-channel analog-to-digital converter interface. The sensor group includes a pressure sensor, a temperature sensor, a triaxial magnetometer, and an accelerometer. The communication protocol stack supports TDMA multiple access and dynamic routing. The concentration regeneration submodule automatically activates when the output voltage of the power generation unit drops beyond a preset threshold, applying a reverse voltage to convert external Na+. + Pump it back into the chamber to restore the concentration gradient.

[0019] The advantages of this invention are: 1. Energy self-sufficient and maintenance-free: It generates electricity using deep-sea pressure, requiring no sunlight, ocean currents, or temperature differences. It can be deployed in any sea area with a depth greater than 500 meters and has a design life of more than 10 years.

[0020] 2. Undetectability across the entire domain: Acoustic domain: No rotating parts, vibration frequency <10Hz, lower than ambient noise, undetectable by passive sonar. Magnetic anomaly domain: After active compensation, static magnetic anomaly <0.1nT, lower than the airborne magnetic anomaly detection threshold. Optical domain: No visible light emission, the outer shell is made of non-reflective material, undetectable by underwater optical equipment. Electromagnetic domain: The magnetic field signal, after camouflage, is statistically indistinguishable from background noise and does not propagate across media into the air.

[0021] 3. Extremely Covert Physical Layer Communication and Application Layer Encryption: Physical Layer: Employing a spread spectrum modulation scheme based on a shared dictionary, completely eliminating the inherent periodicity and cyclic stationary characteristics of traditional Direct Sequence Spread Spectrum (DSSS) signals. The transmitted waveform is indistinguishable from deep-sea background magnetic noise in the time, frequency, and higher-order statistical domains. Eavesdroppers cannot extract any demodulated features through long-term observation, cyclic spectrum analysis, or machine learning. This scheme can operate stably in environments with negative signal-to-noise ratios (down to -10 dB), with significantly lower probabilities of interception (LPI) and detection (LPD) than traditional DSSS or frequency hopping schemes, providing deep-sea communication nodes with a "one-time encryption" level of secure communication at the physical layer. Application Layer: Combining an AES-128 hardware encryption engine, the modulated baseband data frames are encrypted a second time, forming a dual security barrier from the physical layer to the application layer. Point-to-point directional transmission and on-demand name-calling mechanisms further prevent broadcast leakage.

[0022] 4. Anti-sludge self-cleaning: Suspended deployment + low-frequency vibration + superhydrophobic coating ensures long-term protection against burial.

[0023] 5. Modular and Scalable: A single node can power and supply the network for the beacon, while multiple nodes can form a wide area network covering hundreds of kilometers through a three-layer networking architecture. The spacing between nodes in the wide area backbone network is 20-50 kilometers, the spacing between nodes in the medium-distance relay network is 1-5 kilometers, and the spacing between nodes in the local high-speed access network is less than 150 meters. The three layers work together to achieve full coverage from short-distance Mbps-level high-speed transmission to long-distance kb / s-level control signaling.

[0024] 6. Full-scenario adaptive communication: It integrates a dual-resonant magnetic coupling high-speed channel and an ME antenna ultra-long-distance channel, which can extend the communication distance from several meters to kilometers and the data rate from hundreds of kbps to 30Mbps, adapting to complex working conditions such as changes in deep sea water quality and differences in node spacing; the cost of the ME antenna array is less than one-tenth of that of a traditional coil with the same performance, which greatly reduces the cost of wide area networking. Attached Figure Description

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0026] Figure 1 This is a schematic diagram of a deep-sea communication system with low physical characteristics across the entire link, according to the present invention.

[0027] Figure 2 This is a schematic diagram of the internal structure and electrode partitioning of a PSIC power generation unit, which is part of a deep-sea communication system structure with low physical characteristics across the entire link according to the present invention.

[0028] Figure 3 This is a schematic diagram of the layered structure of a gradient multilayer composite membrane for a deep-sea communication system with low physical characteristics across the entire link, according to the present invention.

[0029] Figure 4 This is a block diagram illustrating the principle of dual-resonant magnetic coupling communication and camouflage based on shared dictionary spread spectrum, representing a deep-sea communication system structure with low physical characteristics across the entire link according to the present invention.

[0030] Figure 5 This is a comparison curve of the transmitted signal power spectrum and the Wenz noise spectrum of a deep-sea communication system structure with low physical characteristics across the entire link according to the present invention.

[0031] Figure 6 This is a diagram showing the mooring and anti-siltation layout of a low-physical-feature suspended platform for a full-link low-physical-feature deep-sea communication system structure according to the present invention.

[0032] Figure 7 This diagram illustrates the active anti-siltation vibration frequency domain energy distribution and four-level suppression effect of a deep-sea communication system structure with low physical characteristics across the entire link, as presented in this invention.

[0033] Figure 8 This is a schematic diagram of a PSIC electrode and ME antenna multiplexed programmable switch matrix for a deep-sea communication system with low physical characteristics across the entire link, according to the present invention.

[0034] Figure 9 This is a block diagram of a pulse excitation and back EMF energy recovery circuit for a deep-sea communication system with low physical characteristics across the entire link, according to the present invention.

[0035] Figure 10 This is a multi-node relay network topology and TDMA timing diagram for a deep-sea communication system structure with low physical characteristics across the entire link, according to the present invention.

[0036] Figure 11 This is a flowchart illustrating the intelligent switching mode of a hybrid antenna in a deep-sea communication system structure with low physical characteristics across the entire link, according to the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0039] like Figures 1 to 11 The illustrated end-to-end low physical signature deep-sea communication system includes: A pressure-driven ion energy generation unit includes a sealed cavity, an electrolyte solution with a concentration higher than that of external seawater filled in the cavity, an ion-selective membrane assembly installed on the cavity wall, and a pressure transmission mechanism that transmits external hydrostatic pressure to the internal solution; the ion-selective membrane allows selective transmembrane migration of one type of ion to form an ion current; A dual-resonant magnetic coupling communication unit includes at least one set of coil antennas, an adjustable resonant capacitor array connected in parallel with the coil antennas, and a signal camouflage submodule; the signal camouflage submodule performs pseudo-random spread spectrum and power spectrum shaping on the baseband signal to make the Kullback-Leibler divergence between the transmitted magnetic field signal and the deep-sea background magnetic noise less than 0.1. In terms of signal camouflage, the probability density functions of the transmitted signal s(t) and the background noise n(t) are defined as ps and pn, respectively, and the Kullback-Leibler divergence (relative entropy) between them is: ; When this value is less than 0.1, theoretically, it is impossible to statistically reliably distinguish between signal and noise through observations of a finite length. This invention uses power spectrum shaping and random phase modulation on the transmitted signal to make its higher-order statistics consistent with Gaussian noise, thereby controlling the KL divergence below 0.1 under typical deep-sea magnetic noise background.

[0040] The low physical characteristics suspended platform includes a float made of non-magnetic floating material, a non-metallic or weakly magnetic rigid frame, and a buoyancy adjustment and attitude stabilization system to suspend the platform at the target water depth; the overall static magnetic anomaly of the platform is less than 0.1 nT, and the underwater sound pressure level generated by its mechanical vibration is lower than the marine environmental noise level in the same frequency band. The active anti-fogging and self-cleaning unit includes a vibrator, a cantilever beam structure, and a hydrophobic coating, which periodically vibrates at a frequency of less than 10Hz to remove surface deposits. The integrated energy management and central control unit, comprising a microcontroller, energy storage battery, sensor array, and communication protocol stack, is used for unified scheduling of power generation, energy storage, communication, camouflage, anti-sludge, and concentration regeneration functions.

[0041] The ion-selective membrane is a gradient multilayer composite membrane, comprising, from bottom to top, a high-strength porous support layer, an intermediate transition layer composed of cross-linked polymer and nanoparticles, and a functional separation layer formed by the self-assembly of metal-organic framework UiO-66-NH2 nanocrystals and graphene oxide nanosheets through vacuum filtration; the thickness of the functional separation layer is 50 nm to 500 nm, and the channel size is 0.3 nm to 1.0 nm; the composite membrane exhibits good ion-selectivity for Na+ under a hydrostatic pressure of 10 MPa. + The rejection rate is not less than 95%, and the membrane resistance is not higher than 0.8 Ω·cm².

[0042] The signal camouflage submodule of the dual-resonant magnetic coupling communication unit adopts a spread spectrum modulation scheme based on a shared dictionary, including: a shared waveform dictionary pre-installed at the transmitter and receiver, containing at least 216 distinct spread spectrum sequences, each with a different chip rate; a random mapping encoder that groups the encrypted information bit stream into fixed-length groups and uses a pseudo-random number generator to randomly select a spread spectrum sequence from the dictionary to map each group of information; a power spectrum shaping filter that makes the fitting error between the power spectral density of the output signal and the deep-sea magnetic noise spectrum less than 10%; and an adaptive power controller that adjusts the transmission power according to the channel quality.

[0043] The floating material of the low physical characteristics suspension platform is a composite foam of glass microspheres and epoxy resin with a density of 0.45 g / cm³ to 0.55 g / cm³ and a compressive strength of not less than 50 MPa; the rigid frame material is polyetheretherketone; the platform also includes an active magnetic anomaly compensation coil to control the static magnetic anomaly within 1 meter around the platform to within 0.05 nT.

[0044] The vibrator of the active anti-siltation and self-cleaning unit is an eccentric motor with a power of 0.1W to 1W and a vibration frequency of 1Hz to 10Hz. The cantilever beam is made of PEEK material, and its first-order natural frequency is designed to be much higher than the excitation operating frequency, so that it operates in the quasi-static stiffness-dominated region. The hydrophobic coating is a super-dual-hydrophobic coating of fluorinated carbon nanotubes with a contact angle greater than 150°. The underwater sound pressure level generated by the vibration is more than 10dB lower than the marine environmental noise level in the same frequency band.

[0045] It also includes a magneto-mechanical antenna communication unit, which comprises a layered heterostructure antenna array composed of a magnetostrictive layer and a piezoelectric layer bonded together; the internal electrodes of the pressure-driven ion energy generation unit have a multi-segment structure, and each segment is connected to the power generation circuit or the pulse drive circuit of the magneto-mechanical antenna through a programmable switch matrix; the magneto-mechanical antenna unit is attached to the cantilever beam surface of the active anti-sludge unit; the unit also includes a back electromotive force energy recovery circuit, which is connected between the piezoelectric layer of the magneto-mechanical antenna and the energy storage unit, and recharges the back electromotive force generated by the mechanical vibration recovery to the energy storage unit after the pulse excitation ends.

[0046] The pressure-driven ion energy power generation unit also integrates an electrochemical concentration regeneration submodule, including an auxiliary electrode and a programmable power supply. When the output voltage of the power generation unit drops below a preset threshold, the controller applies a reverse voltage to pump cations in the external seawater back into the cavity through the electrodialysis effect, restoring the concentration gradient.

[0047] A method for achieving undetectable energy and communication in the deep sea includes the following steps: The system is deployed in the target sea area, and the platform is suspended in a clean water layer at a depth of 500 to 1000 meters by buoyancy balance between the buoyancy carrier and the counterweight. The pressure-driven ion energy generation unit utilizes the pressure of deep-sea still water to drive the selective transmembrane migration of ions to generate direct current and charge the energy storage battery. When transmitting data, the communication unit sequentially performs encryption, pseudo-random spread spectrum, spectrum shaping and filtering, and adaptive power control on the baseband signal, and then transmits the magnetic field signal through a dual-resonant magnetic coupling antenna or a magneto-mechanical antenna. The receiving end recovers data through resonant reception, despreading, and decryption; The active anti-siltation unit is activated periodically to vibrate at a frequency below 10Hz to remove surface deposits. When the output voltage of the power generation unit drops below a preset threshold, the concentration regeneration program is activated to restore the internal concentration gradient.

[0048] The spectral shaping filter ensures that the theoretical fitting error between the power spectral density of the transmitted signal and the Wenz ocean noise spectrum within the target frequency band is less than 5%; the adaptive power control estimates the communication distance based on the received signal strength indication and adjusts the transmitted power to keep the signal-to-noise ratio at the receiver near the minimum threshold required for demodulation.

[0049] A deep-sea communication beacon includes a full-link low physical signature deep-sea communication system. The outer shell of the system is coated with a superhydrophobic coating of fluorinated carbon nanotubes. The system integrates a pressure-driven ion energy generation unit, a dual-resonant magnetic coupling communication unit, a magneto-electro-mechanical antenna communication unit, a low physical signature levitation platform, an active anti-silting unit, and a comprehensive energy management and central control unit. The beacon is suspended at a predetermined depth in the deep sea by a buoyancy carrier and a counterweight, autonomously generating electricity, providing covert communication, and anti-silting and self-cleaning capabilities.

[0050] Example 1: Theoretical Model and Material Selection of PSIC Power Generation Unit This embodiment describes in detail the physical model on which the PSIC power generation unit is based and the basis for the selection of key materials.

[0051] For two solution systems separated by an ion-selective membrane, the cation flux and solvent flux The coupled transport behavior can be described by a linear phenomenological equation of irreversible thermodynamics. This is under the influence of hydrostatic pressure difference ΔP and chemical potential difference. Driven by the joint efforts of:

[0052]

[0053] Where Lcc is the ionic conductivity coefficient, Lpp is the hydraulic permeability coefficient, and Lcp=Lpc is the coupling coefficient (satisfying the Onsager reciprocal relation). In a 1000-meter deep-sea environment, Partial molar volume of water Then, the driving contribution of pressure to ion transmembrane migration is:

[0054] The equivalent concentration ratio corresponding to this pressure term is determined by... achievable That is, Cin / Cout ≈ 1.08 times. In actual seawater systems, the ratio of internal concentration to external seawater concentration is usually 5-10 times, corresponding to a chemical potential difference of 4-6 kJ / mol, which is much greater than the pressure term of 180 J / mol. Although the pressure term is smaller than the concentration term in numerical terms, it serves as a continuous and stable driving force, and its core role is to prevent the ion flux from reaching equilibrium with the concentration gradient, thereby maintaining the continuous operation of the power generation process.

[0055] The ion-selective membrane of this invention employs a MOF / GO composite system. The window pore size of UiO-66-NH2 is 0.6 nm, which is intermediate between that of hydrated Na+. + (0.72nm) and dehydrated Na + Within the range of 0.20 nm, selective transport of cations through partial dehydration can be achieved. Mg 2+ (Hydrated diameter 0.86 nm) Due to its large size, it is difficult to penetrate. At the same time, the amino functional groups electrostatically repel divalent cations, and the synergistic effect gives this membrane system a high Na+ content. + / Mg 2+ Selectivity. The Zr-O bond in UiO-66-NH2 has high chemical rigidity. Combined with the multilayer encapsulation and interface modification process of this invention, it is expected to maintain long-term structural stability under 10MPa hydrostatic pressure.

[0056] Taking a single module membrane area of ​​100 cm², and based on conservative estimates of the resistivity (0.8 Ω·cm²) and ion flux data of similar membranes reported in the literature, the theoretical lower limit of the maximum output power of a single module is 50 mW (power density 0.5 mW / cm²). The actual system output power is affected by factors such as the specific preparation process of the membrane material, solution concentration, and temperature, and can be extended to the watt level by connecting multiple modules in series and parallel.

[0057] Example 2: Specific Implementation of a Dual-Resonant Magnetic Coupled Stealth Communication Unit This embodiment describes the antenna structure and modulation camouflage scheme of a dual-resonant magnetically coupled communication unit.

[0058] In the triaxial orthogonal toroidal coil assembly, each coil is wound on a PEEK bobbin, with a coil diameter of 150mm and 37 turns. The winding uses 66×0.07mm Litz wire (66 strands of 0.07mm diameter copper wire twisted together), with a total equivalent diameter of 0.57mm. This specification was chosen to ensure that the diameter of each copper strand and the skin depth are comparable within the target operating frequency band (1-45MHz). The skin depth is 66μm at 1MHz and 21μm at 10MHz. The diameter of each strand is 70μm, which fully utilizes the conductor cross-sectional area across the entire frequency band, reducing the equivalent AC resistance to 20%-30% of that of solid copper wire. The triaxial coils are assembled in a mechanically orthogonal manner, with assembly errors controlled within ±1°. After assembly, the entire assembly is vacuum-sealed with epoxy resin.

[0059] Each coil is connected in parallel to an array of adjustable capacitors, including multiple fixed capacitor branches from 1pF to 1000pF and fine-tuning capacitor branches from 5-20pF and 10-50pF. These are controlled by a microcontroller via analog switching with an on-resistance of <4Ω and a switching time of <50ns. The total tuning capacitor range covers from a few pF to 2000pF, matching the resonance requirements when the coil inductance varies from 0.5-2.0μH. During initial calibration, different capacitor values ​​are sequentially switched and reflected power is monitored to find the combination that minimizes reflection. During communication, recalibration is periodically performed based on the RSSI feedback from the receiver, or rapid fine-tuning (±20% range scanning) is performed near the optimal value to reduce scanning power consumption.

[0060] The signal camouflage submodule operates as follows: On the ground server, a primary mapping (Logistic parameter r=4) and a secondary mapping (Chebyshev cascaded chaotic mapping) generate at least 216 spread spectrum waveforms. The chip length of each waveform varies randomly between 512 and 4096, and the chip rate is uniformly distributed within the range of 1 kHz to 50 kHz, forming a shared waveform dictionary. The dictionary is encrypted using AES-128 and pre-installed on each communication node. The transmitter groups the information bitstream into 128-bit blocks and selects a spread spectrum waveform from the dictionary using a random number generated from the current frame bits and the key as an index. The waveform is then spectrally shaped using a 10th-order IIR digital filter (the filter coefficients are designed based on the Wenz noise spectrum model) to ensure that the fitting error between the power spectral density and the Wenz spectrum is less than 10%. An adaptive power controller then adjusts the power amplifier output. The receiver performs a parallel sliding correlation between the received signal and all waveforms in the dictionary, detects the peak position, and performs an inverse mapping to recover the information. In practical engineering implementations, the waveform library can be pre-classified by chip rate, first screening candidate waveforms at a coarse-grained level before performing fine correlation, thus reducing the real-time computational load.

[0061] Regarding magnetic signal propagation, the magnetic field strength decreases cubically with distance in the near-field region (B∝1 / r³), much faster than the cylindrical attenuation of sound waves. By controlling the transmission power so that the field strength is lower than the ambient magnetic noise level outside a preset safe distance (less than 1 pT / √Hz at 100 meters), low-probability-of-detection communication can be achieved.

[0062] Example 3: Low Physical Characteristics Suspension Platform This embodiment describes the material selection and undetectability design basis of the suspension platform.

[0063] The main buoy is made of glass microspheres / epoxy composite foam, a material with mature applications in deep-sea engineering. It has a density of 0.5-0.7 g / cm³ and a compressive strength of 40-70 MPa, meeting the requirements for 1000-meter deep-sea service in this invention. The rigid frame is integrally machined from PEEK engineering plastic. This material is hydrolytically resistant, dimensionally stable, and has excellent electrical insulation properties, maintaining structural integrity during long-term immersion tests in a simulated 10 MPa deep-sea environment. The mooring cable is made of Dyneema® SK78 ultra-high molecular weight polyethylene fiber. This material has a density 0.97 g / cm³ lower than seawater and a breaking strength far exceeding that of 12mm diameter steel wire ropes (reaching 10-20 tons). It has over ten years of service experience in deep-sea oil and gas platforms and other scenarios, retaining 87% of its original breaking strength after 11,000 hours of aging.

[0064] Regarding acoustic undetectability, according to the Wenz spectrum, the deep-sea ambient noise level around 10 Hz is... After vibration suppression design, the active anti-siltation unit of this invention has a radiated sound pressure level at its main frequency that is more than 10 dB lower than the ambient noise. Regarding magnetic anomaly suppression, the platform body uses non-magnetic materials, supplemented by Helmholtz coil active compensation, suppressing static magnetic anomalies within 1 meter of the platform to within 0.05 nT. Combined with the attenuation characteristics of the magnetic field with distance, the magnetic anomaly is already below the minimum detection threshold of current airborne magnetic anomalies (0.01-0.001 nT under laboratory conditions; in actual marine environments, the detection threshold is higher due to noise from wave-induced magnetic fields and other sources).

[0065] Example 4: Active anti-fogging and self-cleaning unit This embodiment details the design basis and engineering implementation of the vibration parameters. This unit shares a cantilever beam structure with the ME antenna.

[0066] The vibrator uses a miniature eccentric motor with a power of 0.5W and an operating voltage of 5V. The eccentric block has a mass of 0.2g and an eccentricity of 1.5mm. The vibration frequency is controlled to be 3Hz by adjusting the rotation speed. The selection of the vibration frequency is based on the following criteria: this frequency is lower than the frequency band of marine biological activity (usually >20Hz) and the typical detection frequency band of passive sonar (usually >10Hz), while avoiding the sensitive range of shipping noise (10-500Hz) and wind and wave noise (>100Hz) in the Wenz noise spectrum.

[0067] The cantilever beams simultaneously serve as anti-siltation and antenna components. Six PEEK cantilever beams (100mm long, 15mm wide, and 3mm thick) radiate from the central base, with their free ends resting against the inner wall of the outer shell. Calculations show that the first-order natural frequency of the cantilever beams in air is 280Hz, which, after considering the underwater added mass effect, is 170-210Hz, far exceeding the exciter's operating frequency of 3Hz. The system operates in the quasi-static stiffness-dominated region, exhibiting stable displacement response. The ME antenna array elements are attached to the cantilever beam surface near the fixed end. In transmit mode, high-voltage pulses (50-200V) are applied to the PZT layer, generating high-frequency mechanical strain ranging from hundreds of Hz to several kHz. This strain is amplified by the cantilever beams and radiates a low-frequency electromagnetic field. The two modes do not interfere with each other due to the frequency difference of more than two orders of magnitude.

[0068] Four levels of suppression measures are arranged on the vibration transmission path. In the first level, a silicone rubber gasket with a Shore hardness of 40A is embedded between the vibration exciter and the rigid frame, the power-on duty cycle is limited to 20% in combination with a soft-start circuit, so that the impact acceleration is reduced to less than 60% of the initial value. In the second level, a polyurethane elastomer with high internal friction and a thickness of 5mm is arranged between the rigid frame and the outer casing, and the combined vibration isolation measure achieves a vibration transmissivity of 0.3 in the 3-5Hz frequency band. In the third level, a thin layer of locally resonant acoustic metamaterial with a thickness of 8mm, which is composed of periodically arranged rubber-wrapped tungsten spheres, is laid on the inner side of the outer casing, so that the vibration on the outer casing surface propagates mainly in the form of attenuated waves, and the radiation efficiency η is reduced from 1 to below 0.1. In the fourth level, a 2mm thick polyurethane / hollow glass microsphere composite damping layer (loss factor ), further attenuates the vibration energy by 30%.

[0069] For a small vibrating structure immersed in an infinite fluid, the far-field radiated sound pressure level SPL and the vibration acceleration amplitude a satisfy the approximate relationship of the dipole radiation model. Under the condition that the radiation efficiency η is much lower than 1, the radiated sound pressure level can be expressed as:

[0070] where ρ is the seawater density (1025kg / m³), c is the speed of sound in water (1500m / s), S is the vibration radiation surface area (m²), η is the radiation efficiency, r is the observation distance (taken as 1m), and pref=1μPa is the reference sound pressure. Substitute the typical values , , solve for the upper acceleration limit that makes , and obtain ². After the above four levels of vibration suppression measures, the vibration acceleration amplitude on the platform surface is controlled at the order of 0.001m / s². At the dominant frequency of 3Hz, the radiated sound pressure level at 1m from the platform is 32dB re 1μPa, which is 13dB lower than the deep-sea ambient noise level (45dB re 1μPa) in the same frequency band, satisfying the undetectable criterion of SL-TL<NL.

[0071] The vibration exciter runs regularly for 30 seconds every day, with an average daily energy consumption of 0.0083Wh, which is less than 0.1% of the total power generation of the system. In the standby mode, the anti-silt system continuously vibrates at a low frequency of 3Hz, while at least one electrode partition is floating and the environmental magnetic field signal is monitored through a 10MΩ high-impedance detection circuit. When the detected signal intensity exceeds the preset threshold (0.1pT), the wake-up circuit outputs an interrupt signal to the main control, and the system enters the receiving mode or the transmitting mode — the anti-silt vibration here also serves as the signal sensing front end, so that the standby power consumption is reduced to below 0.1mW.

[0072] Embodiment 5: PSIC electrode and ME antenna multiplexing and energy recovery This embodiment describes in detail the switching logic and energy recovery circuit of the programmable switch matrix.

[0073] The PSIC power generation unit is made of platinum-plated titanium mesh. The internal electrodes are divided into independent 4×4 arrays with a total area of ​​100 cm². Each area is isolated by a 0.5 mm wide insulating gap. Each area is led out to the switching matrix through an independent conductive connection line. The switching matrix consists of an 8×8 MOSFET solid-state relay array with a 4 Ω on-resistance and a <1 nA off-resistance, controlled by a microcontroller.

[0074] The system switches between four operating modes.

[0075] (1) Power generation and charging mode: All electrode zones are connected to the common bus of the PSIC power generation circuit. The MPPT boost converter maintains the bus voltage. Due to the accumulation of charge on the electrode surface due to ion migration, the voltage gradually rises from 2.5V to 8V (typical value) within 300 seconds.

[0076] (2) Signal receiving mode: The designated partition is switched to the input of the low noise preamplifier to receive ultra-low frequency magnetic field signals.

[0077] (3) Beacon Broadcast Mode: When the voltage of any electrode zone reaches the preset threshold of 8-10V, the MOSFET corresponding to that zone is disconnected from the power generation circuit within 50μs and simultaneously switched to the input of the pulse forming network. The energy accumulated on the electrode capacitor is instantly released to both ends of the piezoelectric layer of the ME antenna unit (100V, 10μs pulse width), exciting the antenna to radiate electromagnetic waves.

[0078] (4) Directional long-distance transmission mode: Multiple electrode zones corresponding to multiple antenna units transmit in a coordinated manner, and beamforming is achieved by adjusting the pulse timing of each zone.

[0079] The back EMF energy recovery process occurs after the PZT lamination pulse excitation ends, during the mechanical vibration recovery process. The back EMF generated is then rectified by a Schottky diode bridge and converted to a 0.5-2V input, 3.3V output DC / DC boost converter, and recharged back into the energy storage battery. Actual measurements show that in 50 pulse emission cycles, the average efficiency of the energy recovery circuit is 18.7%, meaning that out of 100 energy units consumed, 18.7 units can be recovered back to the battery, resulting in a 15% reduction in net energy consumption.

[0080] Example 6: Multi-node relay networking and intelligent switching of hybrid antennas This embodiment describes the protocol framework and antenna switching logic for multi-node networking.

[0081] Multiple beacon nodes form a distributed network via magnetic induction channels. Under the TDMA framework, the surface or mother ship master control node transmits synchronization and time references in broadcast time slots, and each underwater node uploads data or forwards signals from neighboring nodes in its allocated data time slots.

[0082] The deep-sea beacon integrates two types of antennas: a dual-resonant magnetically coupled antenna with a three-axis orthogonal loop coil covering a frequency range of 1-45MHz, and a 3×5 element ME antenna array covering a frequency range of 100Hz-50kHz. Both share a PSC power generation module, energy storage battery, and main control chip. Antenna switching is achieved through a solid-state RF switch with a switching time of less than 10μs. The system monitors received signal strength, signal-to-noise ratio, packet error rate, and environmental parameters such as water depth and temperature in real time, with the intelligent switching controller executing the state machine logic. High-speed mode: When the estimated distance is less than 150 meters and the signal-to-noise ratio is higher than 15dB, the main antenna is a dual resonant magnetic coupling antenna with a data rate of 1-30Mbps, and the ME antenna is only used to listen to the signaling.

[0083] Long-range mode: When the estimated distance is greater than 200 meters or the signal-to-noise ratio is less than 10dB, the ME antenna array is used as the main antenna, with a data rate of 10-500kbps and a communication distance of more than 700 meters.

[0084] Broadcast mode: When omnidirectional control commands need to be transmitted, the ME antenna array is used for omnidirectional radiation.

[0085] Energy-saving standby mode: After a timeout due to no communication task, the system enters sleep mode, alternately waking up the two antennas to perform channel scanning, with an average power consumption of less than 0.5W. A hysteresis window (±10%) is set for the decision threshold to prevent ping-pong switching.

[0086] The low-frequency signal radiated by the ME antenna also adopts a spread spectrum modulation scheme based on a shared dictionary. It shares the same waveform dictionary and random mapping coding logic with the dual resonant magnetic coupling antenna. The dictionary specifically reserves a subset of low-speed waveforms with chip rates between 100Hz and 10kHz for the ME antenna. After the power spectrum is shaped, it matches the deep-sea magnetic noise background in the 10-100Hz frequency band with a fitting error of <10%.

[0087] Multiple beacons form a three-layer network architecture. The first layer is a wide-area backbone network, employing metamaterials to enhance magnetic induction, with node spacing of 20-50 kilometers, enabling network-wide time synchronization, route maintenance, and low-speed control command broadcasting. The second layer is a medium-range relay network, using ME antenna arrays, with node spacing of 1-5 kilometers, enabling hop-by-hop data relay forwarding. The third layer is a local high-speed access network, employing dual-resonant magnetically coupled antennas, with node spacing less than 150 meters, achieving Mbps-level high-speed data transmission.

[0088] When a beacon needs to send a large amount of data to a distant node, it first negotiates link parameters and confirms the target's location through a low-speed channel on the wide-area backbone network. Then, depending on the distance, it chooses to transmit directly through the wide-area backbone network (20-50 km range), relay hop-by-hop through ME antennas (1-5 km per hop), or switch to a dual-resonant magnetically coupled directional beam for high-speed local transmission. The three-layer channel works in concert, enabling the entire network to simultaneously possess wide-area coverage (20-50 km node spacing) and high local bandwidth.

[0089] Example 7: Magneto-electro-mechanical antenna unit and deep-sea packaging This embodiment describes the structure of the ME antenna unit, array assembly, and a three-level hermetically sealed packaging scheme for deep-sea environments.

[0090] The ME antenna element employs a three-layer heterogeneous structure of FeGa / steel / PZT, with a FeGa layer thickness of 50μm, a steel layer thickness of 20μm, and a PZT layer thickness of 100μm. The overall element size is 80mm × 20mm × 2.65mm, significantly smaller than one-thousandth of the corresponding radiation frequency. During fabrication, epoxy conductive adhesive is used to bond each layer sequentially at room temperature, followed by curing at 1MPa for 24 hours. After curing, a DC bias voltage of 500V / mm is applied to the electrodes at both ends of the PZT for secondary polarization. The bias magnetic route consists of a small, embedded N52 neodymium magnet and a pure iron yoke, generating a uniform bias magnetic field of 10kA / m within the FeGa layer. A total of 15 elements are arranged in a 3×5 matrix with a spacing of 20mm. Each element's piezoelectric electrode is independently led out to a shared drive circuit, and the phase of the drive signal is independently adjusted via a phase shifter controlled by an FPGA.

[0091] For the extreme environment of deep sea at 1000 meters (10MPa hydrostatic pressure), high salinity, and long-term service, this embodiment adopts a three-level sealing and system integration packaging strategy.

[0092] Unit-level vacuum potting and primary encapsulation: Each ME antenna unit (FeGa / steel / PZT three-layer structure and bias magnetic circuit) is placed entirely in a dedicated mold and potted using low-viscosity, high-insulation, hydrolysis-resistant EP-6010HT epoxy resin under vacuum negative pressure. Vacuum potting completely removes gas from the interlayer spaces and micropores on the material surface, allowing the epoxy resin to fully wet all interfaces. After curing, a continuous and dense protective shell with a thickness of 0.5-1.0 mm is formed on the outer surface of the unit. This epoxy resin layer has been tested for 5000 hours in a simulated deep-sea environment (10MPa, 35ppt salinity, 60℃ accelerated aging) without significant hydrolysis or decrease in adhesion.

[0093] Array-level hermetically sealed skeleton secondary packaging: 15 units, after primary packaging, are fixed in a 3×5 array on a skeleton made of PEEK engineering plastic. PEEK material has extremely low water absorption (<0.1%), high mechanical strength (>90MPa tensile strength), and excellent hydrolysis resistance. The electrode leads of each unit are connected to a miniature watertight connector socket via a flexible FPC cable.

[0094] The entire pressure-resistant chamber is encapsulated in three stages: the array, after two stages of encapsulation, is housed within a sealed chamber made of TC4 titanium alloy. The chamber wall thickness, determined by finite element analysis, is 2.5mm (safety factor ≥3). A redundant sealing structure with double fluororubber O-rings and metal C-rings is used between the chamber and the end caps, capable of withstanding 15MPa hydrostatic pressure without leakage. A PEEK electromagnetic window is designed at the position corresponding to the antenna radiating surface on the chamber; its thickness has been optimized through electromagnetic simulation, achieving a magnetic field transmittance >90% in the 10-50kHz frequency band. The sealed chamber is filled with insulating cooling silicone oil and equipped with a pressure-compensating diaphragm. This allows the flexible rubber bladder to connect with the external seawater, ensuring that the internal oil pressure remains balanced with the external hydrostatic pressure, thereby minimizing the net pressure difference on the chamber walls and further improving long-term reliability.

[0095] All electrical leads (15 driving electrodes and bias magnetic circuit monitoring lines) are led out through multi-core miniature watertight connectors (titanium alloy housing and pins) on the bulkhead, ensuring airtightness under 10MPa pressure. .

[0096] The packaged ME antenna array measures 120mm × 220mm × 30mm and is fixed to the inner wall of the beacon housing. Its electrical interface is connected to the solid-state relay array antenna switching switch on the main control board and is managed by an intelligent switching controller. The ME antenna array and the triaxial orthogonal loop coil group coexist within the same beacon, sharing the same PSIC power supply and signal camouflage submodule.

[0097] Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A deep-sea communication system with low physical signature across the entire link, characterized in that: include: A pressure-driven ion energy generation unit includes a sealed cavity, an electrolyte solution with a concentration higher than that of external seawater filled in the cavity, an ion-selective membrane assembly installed on the cavity wall, and a pressure transmission mechanism that transmits external hydrostatic pressure to the internal solution; the ion-selective membrane allows selective transmembrane migration of one type of ion to form an ion current; A dual-resonant magnetic coupling communication unit includes at least one set of coil antennas, an adjustable resonant capacitor array connected in parallel with the coil antennas, and a signal camouflage submodule; the signal camouflage submodule performs pseudo-random spread spectrum and power spectrum shaping on the baseband signal to make the Kullback-Leibler divergence between the transmitted magnetic field signal and the deep-sea background magnetic noise less than 0.

1. The low physical characteristics suspended platform comprises a float made of non-magnetic floating material, a non-metallic or weakly magnetic rigid frame, and a buoyancy adjustment and attitude stabilization system that suspends the platform at a target water depth; the overall static magnetic anomaly of the platform is less than 0.1 nT, and the underwater sound pressure level generated by its mechanical vibration is lower than the marine environmental noise level of the same frequency band. The active anti-fogging and self-cleaning unit includes a vibrator, a cantilever beam structure, and a hydrophobic coating, which periodically vibrates at a frequency of less than 10Hz to remove surface deposits. The integrated energy management and central control unit, comprising a microcontroller, energy storage battery, sensor array, and communication protocol stack, is used for unified scheduling of power generation, energy storage, communication, camouflage, anti-sludge, and concentration regeneration functions.

2. The end-to-end low physical signature deep-sea communication system according to claim 1, characterized in that: The ion-selective membrane is a gradient multilayer composite membrane, comprising, from bottom to top, a high-strength porous support layer, an intermediate transition layer composed of cross-linked polymer and nanoparticles, and a functional separation layer formed by the self-assembly of metal-organic framework UiO-66-NH2 nanocrystals and graphene oxide nanosheets through vacuum filtration; the thickness of the functional separation layer is 50 nm to 500 nm, and the channel size is 0.3 nm to 1.0 nm; the composite membrane exhibits good ion selectivity for Na+ under a hydrostatic pressure of 10 MPa. + The rejection rate is not less than 95%, and the membrane resistance is not higher than 0.8 Ω·cm².

3. The end-to-end low physical signature deep-sea communication system according to claim 1, characterized in that: The signal camouflage submodule of the dual-resonant magnetic coupling communication unit adopts a spread spectrum modulation scheme based on a shared dictionary, including: a shared waveform dictionary pre-installed at the transmitter and receiver, the dictionary containing at least 2 16 A set of distinct spreading sequences, each with a different chip rate; a random mapping encoder that groups the encrypted information bit stream into fixed-length blocks and uses a pseudo-random number generator to randomly select a spreading sequence from a dictionary to map each block of information; a power spectrum shaping filter that ensures the fitting error between the power spectral density of the output signal and the deep-sea magnetic noise spectrum is less than 10%; and an adaptive power controller that adjusts the transmit power according to the channel quality.

4. The end-to-end low physical signature deep-sea communication system according to claim 1, characterized in that: The floating material of the low physical characteristic suspension platform is a composite foam of glass microspheres and epoxy resin with a density of 0.45 g / cm³ to 0.55 g / cm³ and a compressive strength of not less than 50 MPa; the rigid frame material is polyetheretherketone; the platform also includes an active magnetic anomaly compensation coil to control the static magnetic anomaly within 1 meter around the platform to within 0.05 nT.

5. A deep-sea communication system with low physical signature across the entire link according to claim 1, characterized in that: The exciter of the active anti-siltation and self-cleaning unit is an eccentric motor with a power of 0.1W to 1W and a vibration frequency of 1Hz to 10Hz; the cantilever beam is made of PEEK material, and its first natural frequency is designed to be much higher than the excitation operating frequency, so that it operates in the quasi-static stiffness-dominant region; the hydrophobic coating is a fluorinated carbon nanotube super-dual-hydrophobic coating with a contact angle greater than 150°; the underwater sound pressure level generated by the vibration is more than 10dB lower than the marine environmental noise level in the same frequency band.

6. The end-to-end low physical signature deep-sea communication system according to claim 1, characterized in that: It also includes a magneto-mechanical antenna communication unit, which comprises a layered heterostructure antenna array composed of a magnetostrictive layer and a piezoelectric layer bonded together; the internal electrodes of the pressure-driven ion energy generation unit have a multi-segment structure, and each segment is connected to the power generation circuit or the pulse drive circuit of the magneto-mechanical antenna through a programmable switch matrix; the magneto-mechanical antenna unit is attached to the cantilever beam surface of the active anti-sludge unit; the unit also includes a back electromotive force energy recovery circuit, which is connected between the piezoelectric layer of the magneto-mechanical antenna and the energy storage unit, and recharges the back electromotive force generated by the mechanical vibration recovery to the energy storage unit after the pulse excitation ends.

7. A deep-sea communication system with low physical signature across the entire link according to claim 1, characterized in that: The pressure-driven ion energy power generation unit also integrates an electrochemical concentration regeneration submodule, including an auxiliary electrode and a programmable power supply. When the output voltage of the power generation unit drops below a preset threshold, the controller applies a reverse voltage to pump cations in the external seawater back into the cavity through the electrodialysis effect, restoring the concentration gradient.

8. A method for realizing undetectable energy and communication in the deep sea using the system described in any one of claims 1 to 7, characterized in that: Includes the following steps: The system is deployed in the target sea area, and the platform is suspended in a clean water layer at a depth of 500 to 1000 meters by buoyancy balance between the buoyancy carrier and the counterweight. The pressure-driven ion energy generation unit utilizes the pressure of deep-sea still water to drive the selective transmembrane migration of ions to generate direct current and charge the energy storage battery. When transmitting data, the communication unit sequentially performs encryption, pseudo-random spread spectrum, spectrum shaping and filtering, and adaptive power control on the baseband signal, and then transmits the magnetic field signal through a dual-resonant magnetic coupling antenna or a magneto-mechanical antenna. The receiving end recovers data through resonant reception, despreading, and decryption; The active anti-siltation unit is activated periodically to vibrate at a frequency below 10Hz to remove surface deposits. When the output voltage of the power generation unit drops below a preset threshold, the concentration regeneration program is activated to restore the internal concentration gradient.

9. A method for realizing undetectable energy and communication in the deep sea according to claim 8, characterized in that: The spectral shaping filter ensures that the theoretical fitting error between the power spectral density of the transmitted signal and the Wenz ocean noise spectrum within the target frequency band is less than 5%; the adaptive power control estimates the communication distance based on the received signal strength indication and adjusts the transmitted power to keep the signal-to-noise ratio at the receiver near the minimum threshold required for demodulation.

10. A deep-sea communication beacon, characterized in that: The system comprising any one of claims 1 to 7 has an outer shell coated with a superhydrophobic coating of fluorinated carbon nanotubes, and integrates the pressure-driven ion energy generation unit, the dual-resonant magnetic coupling communication unit, the magneto-electro-mechanical antenna communication unit, the low physical characteristic suspension platform, the active anti-silting unit, and the integrated energy management and central control unit; the beacon is suspended at a predetermined depth in the deep sea by a buoyancy carrier and a counterweight, autonomously generating electricity, providing covert communication, and anti-silting self-cleaning.

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