Secret communication system of unmanned aerial vehicle

Abstract

The invention discloses a secret communication system of an unmanned aerial vehicle, which relates to the technical field of secret communication of the unmanned aerial vehicle and comprises a secret key generation and distributed storage unit, a dynamic secret key updating unit, a secret key destruction and tracing unit, a multi-band sensing and interference identification unit and a combined regulation and control unit. A dynamic key is generated through a chaos algorithm, and the security of the key is ensured in combination with block chain fragmentation storage and GPS binding encryption; updating the key according to the risk level, and transmitting the fragments by using an anti-quantum channel; after the communication is finished, the secret key fragments are invalidated, and anomaly detection and traceability are realized; scanning a multi-band frequency spectrum in real time, identifying an interference type and optimizing the model; and according to the interference intensity and the energy efficiency demand, dynamically switching the frequency bands, adjusting the power and enhancing the anti-interception capability. The problems that an existing unmanned aerial vehicle communication system is insufficient in safety, weak in anti-interference capacity, incomplete in key management mechanism and the like are effectively solved, and the safety, the anti-interference performance and the energy efficiency performance of unmanned aerial vehicle communication are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of UAV secure communication, and specifically to a secure communication system for UAVs. Background Art

[0002] With the rapid development of UAV technology, its applications in civilian and commercial fields are becoming increasingly widespread. However, the security and confidentiality of UAV communication face severe challenges. Traditional UAV communication systems mostly use single-band transmission, which is vulnerable to interference and interception. Especially in complex electromagnetic environments or hostile environments, the stability and security of the communication link are difficult to guarantee. In addition, there are many deficiencies in the key management of existing communication systems. For example, the key distribution, storage, and update mechanisms are not flexible enough and are easily cracked or leaked, resulting in the theft or tampering of communication content.

[0003] In the modern communication environment, UAVs need to cope with various interference and attack means, such as narrowband interference, broadband noise interference, and active attacks by malicious nodes. In the prior art, although there are some anti-interference methods, most of them can only deal with specific types of interference and lack the comprehensive recognition and dynamic response capabilities for multiple types of interference. At the same time, traditional communication systems also have deficiencies in energy efficiency optimization and cannot dynamically adjust power and frequency bands according to the real-time communication environment and task requirements, resulting in low communication efficiency and high energy consumption. In addition, the existing systems lack effective risk assessment and dynamic adjustment mechanisms in the key management process and cannot update keys in a timely manner according to changes in the network environment, further increasing the risk of communication being cracked.

[0004] To solve the above defects, a technical solution is provided now. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of insufficient security, weak anti-interference ability, and imperfect key management mechanism existing in the existing UAV communication system, and to propose a secure communication system for UAVs.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A secure communication system for UAVs, comprising: A key generation and distributed storage unit that generates dynamic keys through a chaotic algorithm and realizes the secure distribution and anti-attack storage of keys by combining blockchain sharding storage and GPS-bound encryption; A dynamic key update unit that triggers key updates based on the risk level, generates new keys using PBFT consensus, and transmits shards through anti-quantum channels; A key destruction and traceability unit that invalidates key shards after communication ends and realizes anomaly detection and traceability by combining machine learning and blockchain logs; Multi-band sensing and interference recognition unit, which is used to scan the multi-band spectrum in real time, classify the interference types by using lightweight CNN, and optimize the model through online learning; Joint regulation unit, which is used to dynamically switch the frequency band, adjust the power according to the interference intensity and energy efficiency requirements, and enable beamforming to enhance the anti-interception ability.

[0007] Furthermore, the process of the key generation and distributed storage unit is as follows: Adopt the chaotic sequence algorithm to generate random key seeds, and combine with the unique identification code of the UAV to generate the initial key ; Encrypt through the hash algorithm to generate the final key ; Use the Shamir secret sharing algorithm to divide into n slices, and store the slices in multiple nodes of the blockchain network; and use the dynamic slicing strategy to adaptively adjust the number of slices; When using the Shamir secret sharing algorithm to slice the key , introduce double encryption: The first layer of encryption: encrypt each slice ; The second layer of encryption: bind with the current position coordinates of the UAV to generate the final slice ; Allocate the slice storage locations according to the risk level: store in the public chain nodes ; Store in the consortium chain nodes ; The slice storage metadata includes the slice ID and the storage location, which are recorded and encrypted by the smart contract; When the UAV needs to establish communication with the ground station, submit to the smart contract: the digital signatures of both parties; the current GPS coordinates are used to decrypt the slices; the smart contract verifies: the validity of the signature; whether the deviation between the GPS coordinates and the coordinates at the time of slice storage is within the allowable range, and the allowable deviation range is ≤10km; The smart contract retrieves the valid slices from the public chain and the consortium chain according to the metadata; if the number of available slices ≥ k, enter the recombination process; otherwise, trigger the key update; for each slice Execute: restore using k slices through the Shamir algorithm; Periodic update: force an update of the slicing rules every 24 hours, even if R does not change; Event-driven update: trigger an update immediately when the following events are detected: the number of slice call failures > 3 times; the UAV position moves more than 100km; the credibility of the blockchain node drops by more than 20%; generate new slicing rules; mark the old slices as invalid, and store the new slices according to the rules again.

[0008] Furthermore, the specific process of the dynamic sharding strategy is as follows: Evaluate the network risk level R by collecting the following parameters in real time through a smart contract: Node credibility: Based on historical behavior scores, including sharding call compliance and response latency; Attack frequency: The number of abnormal access requests detected per unit time; Cross-chain communication latency: The data synchronization time between the public chain and the consortium chain; Automatically adjust the sharding parameters according to the risk level R, and the process is as follows: When the risk level R ≤ 0.3, it is judged as a low risk, then the number of shards n = 3, and the recombination threshold k = 2; 60% of the shards are stored on the public chain and 40% are stored on the consortium chain for the shard storage location selection; When the risk level 0.3 < R ≤ 0.7, it is judged as a medium risk, then n = 5, k = 3, and 50% of the shards are stored on each of the public chain and the consortium chain; When the risk level R > 0.7, it is judged as a high risk, n = 7, k = 4, and 30% of the shards are stored on the public chain and 70% are stored on the consortium chain; Sharding rule formula: ; where n represents the number of shards; k represents the minimum number of shards required for recombining the key; R represents the network risk level.

[0009] Furthermore, the specific operation steps of the dynamic key update unit are as follows: When the drone and the ground station initiate a communication request, submit the following information to the blockchain network: Digital signature: A two-party signature based on the ECDSA algorithm to verify the legitimacy of the identity; Real-time risk level R1: Obtain the current network risk level R1 from the blockchain network and analyze it through the malicious node ratio and attack frequency; The smart contract performs double verification, including identity verification: Check the validity of the signature to ensure that both parties are legal devices; Risk level threshold judgment: When R1 ≥ 0.5, trigger forced key update; When R1 < 0.5, trigger periodic update only when the communication interval exceeds the set time; At the same time, adjust the number of PBFT consensus nodes according to the real-time risk level R1. When R1 < 0.3, 3 nodes participate in the consensus; When R1 ≥ 0.3, 7 nodes participate in the consensus; The consensus group nodes need to meet the historical credibility score ≥ 80% and be physically dispersed; The consensus group generates a new key through the PBFT algorithm ; The specific process: Proposal stage: The primary node generates a random number seed and broadcasts it to other nodes; Verification stage: The node verifies the legitimacy of the seed and generates ; Key Sharding: Adopt a dynamic sharding strategy, and adjust the number of shards n and the threshold k according to R; The new key shards are transmitted to the UAV and the ground station through a quantum-secure channel: Sharded Data Encryption: Use the NTRU quantum-resistant encryption algorithm to protect the transmission process; Dynamic Selection of Transmission Path: Select the optimal blockchain node path according to the real-time network latency.

[0010] Furthermore, the specific operation steps of the key destruction and traceability unit are as follows: After the UAV completes the communication task, it sends an encryption termination instruction to the blockchain network, including: the communication session ID, i.e., the hash value, the current key version number, and the dual digital signatures of the UAV and the ground station; The smart contract performs the following operations: Associated Shard Retrieval: Locate all associated key shards according to the session ID and the key version number; Shard Status Update: Mark the shards as invalid status and write them into the blockchain; Storage Isolation: The invalid shards remain on the chain but are moved to a read-only storage area, and any call operations are prohibited; The smart contract monitors the following metrics in real time: Shard Call Frequency: The number of shard calls per unit time; Access Source IP: Detect node access from unconventional geographical locations; Node Behavior Pattern: Identify abnormal behaviors through a machine learning model, including abnormal shard call timing; Classify different abnormal events, and trigger responses according to different threat levels, including: Low-level Abnormalities: Record logs and do not alarm for the time being; Medium-level Abnormalities: Freeze the shard call permission and notify the administrator; High-level Abnormalities: Determine as an attack and trigger an emergency key destruction; For abnormal node location, combine the node registration information stored in the blockchain to locate the physical device corresponding to the abnormal IP, extract the transaction hash, digital signature, and timestamp of the abnormal operation, and generate an immutable forensic report; At the same time, the smart contract automatically executes, including adding the abnormal node to the blacklist, prohibiting it from participating in subsequent consensus or shard storage, and triggering the key update unit to immediately generate a new key to replace the attacked key, and push an alarm message to the security center.

[0011] Furthermore, the specific operation steps of the multi-band sensing and interference identification unit are as follows: The UAV is equipped with a wide-band spectrum scanning chip, which covers the L band of 1-2 GHz, the C band of 4-8 GHz, and the Ku band of 12-18 GHz, and scans the spectrum every 10 ms; Collect the signal strength and noise power parameters of each frequency band; Apply wavelet transform to the original spectrum data to filter out environmental background noise; generate a spectrum feature matrix, including: peak frequency, bandwidth, instantaneous power change rate; frequency domain entropy; Use a pre-trained lightweight CNN model to perform interference classification. The specific structure of the pre-trained lightweight CNN model is an input layer [128x128 spectrogram], 3 convolutional layers + 2 fully connected layers: Input normalization: Normalize the spectrum data to the range [-1, 1]; Interference type determination: Narrowband interference: Output probability > 0.8 and meet the following conditions: Main lobe width < 5 MHz, peak power > -70 dBm; Instantaneous power change rate > 10 dB / ms; Wideband noise interference: Output probability > 0.7 and meet: Spectrum flatness > 0.9, and standard deviation < 2 dB; Frequency domain entropy > 6.0; Interference intensity quantization: Divide into levels according to the signal-to-noise power ratio: Low intensity is SNR < 10 dB, medium intensity is 10 dB ≤ SNR ≤ 20 dB, and high intensity is SNR > 20 dB; Incremental training: If an unknown interference pattern is detected, that is, CNN confidence < 0.6, trigger the following process: Collect new spectrum data and label it, specifically through manual review or assisted by a rule engine; perform model fine-tuning on the edge computing unit to update the convolutional kernel weights; synchronize the new model parameters to the blockchain network for other drone nodes to download and verify; The interference result output and response process is as follows: Generate an interference map, construct a spatio-temporal interference heat map, including: interference type, intensity, and duration of each frequency band; interference source azimuth; The heat map is uploaded to the ground command center through an encrypted channel; Trigger real-time anti-interference strategies, and generate control commands according to the recognition results: Narrowband interference: Trigger the dynamic frequency band switching unit to hop to an interference-free sub-band; Wideband interference: Trigger the multi-band cooperative transmission unit to start redundant coding; High-intensity interference: Enable the decoy signal emission module to attract enemy interference resources; The spectrum scanning chip adopts electromagnetic shielding packaging to prevent external injected interference; built-in self-checking circuit to regularly verify the ADC sampling accuracy; if the scan data is abnormal for 3 consecutive times, switch to the backup spectrum database.

[0012] Furthermore, the specific operation steps of the joint regulation unit are as follows: Synchronously obtain the spectrum status, channel quality and environmental parameters, and generate a spectrum-power joint decision matrix; The process of frequency band selection and transmission mode switching is as follows: Dynamic election of the primary frequency band: Frequency band scoring model: Each frequency band score ; where S is the frequency band score; SNR is the signal-to-noise ratio; Select the frequency band with the highest score as the primary channel. If its interference intensity exceeds the threshold of -90 dBm, enable the standby frequency bands in sequence, i.e., C band → L band; Activation of multi-band cooperative transmission: The triggering condition is: The interference intensity of all frequency bands > -85 dBm and BER > 1e-4; Data segmentation and encoding: The data packet is segmented into 3 sub-streams, i.e., each of the L band, C band, and Ku band carries 1 sub-stream; Add Reed-Solomon redundant encoding to each sub-stream; Parallel transmission: Transmit the three sub-streams synchronously through software-defined radio; The process of adaptive power-beam cooperative regulation is as follows: Dynamic power calculation: Free space loss compensation: According to the formula Calculate the theoretical loss; where L represents the free space loss; d represents the communication distance; λ represents the signal wavelength; Dynamically adjust the transmit power according to the loss value L to keep the received power above -80 dBm; When the interference intensity > -80 dBm and the stealth requirement level ≥ 2, obtain the target direction angle through the phased array antenna; Calculate the beam pointing angle θ, and adjust the phase of the array elements to align the main lobe with the receiving end; Generate a null in the interference direction to suppress the reception of interference signals.

[0013] Compared with the prior art, the beneficial effects of the present invention are: (1) In the present invention, through an innovative key management and storage mechanism, the security of UAV communication is significantly improved; The key generation and distributed storage unit uses the chaotic algorithm to generate dynamic keys, and combines blockchain sharding storage and GPS-bound encryption to achieve the secure distribution and attack-resistant storage of keys; At the same time, the dynamic key update unit triggers key updates based on the risk level and generates new keys through PBFT consensus to ensure that the keys always maintain a high level of security during the communication process; In addition, the key destruction and traceability unit can invalidate key shards after the communication ends, and combines machine learning and blockchain logs to achieve anomaly detection and traceability, further ensuring the confidentiality and security of the communication; (2) In the present invention, the multi-band sensing and interference recognition unit can scan the multi-band spectrum in real time, use lightweight CNN to classify interference types, and optimize the model through online learning, effectively improving the accuracy and real-time performance of interference recognition; the joint control unit dynamically switches frequency bands, adjusts power according to interference intensity and energy efficiency requirements, and enables beamforming to enhance anti-interception ability, significantly improving the anti-interference performance and energy efficiency of UAV communication; the comprehensive anti-interference and energy efficiency optimization strategy enables the UAV communication system to maintain stable and efficient communication capabilities in complex electromagnetic environments. (3) In the present invention, by combining advanced technologies such as blockchain technology, quantum-resistant encryption algorithms, dynamic key management, multi-band sensing and interference recognition, a highly secure, flexible and efficient UAV secure communication system is constructed; it can not only effectively cope with various threats in modern communication environments, but also has good adaptability and scalability, and can meet the high security requirements for UAV communication in civil and commercial fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] For the convenience of those skilled in the art to understand, the present invention will be further described below in conjunction with the accompanying drawings. Figure 1 It is the system general block diagram of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0016] It should be understood that the terms "including" and "comprising" used in the specification and claims of this disclosure indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their combinations.

[0017] It should also be understood that the terms used in this disclosure specification are only for the purpose of describing specific embodiments, and are not intended to limit this disclosure. As used in this disclosure specification and claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms. It should be further understood that the term "and / or" used in this disclosure specification and claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0018] Such as Figure 1As shown in the figure, a secure communication system for an unmanned aerial vehicle (UAV) includes a key generation and distributed storage unit, a dynamic key update unit, a key destruction and traceability unit, a multi-band sensing and interference recognition unit, and a joint regulation unit; The key generation and distributed storage unit generates dynamic keys through a chaotic algorithm, and combines blockchain sharding storage and GPS-bound encryption to achieve secure key distribution and anti-attack storage; A random key seed is generated using a chaotic sequence algorithm (such as the Lorenz chaotic model), and an initial key is generated in combination with the unique identification code of the UAV (such as the IMEI code); ; Through a hashing algorithm (such as SHA-256) for to encrypt and generate the final key; ; Use the Shamir secret sharing algorithm to divide into n shards (for example, n = 5), and store the shards in multiple nodes of the blockchain network; and use a dynamic sharding strategy to adaptively adjust the number of shards. The specific process of the dynamic sharding strategy is as follows: Evaluate the network risk level R by collecting the following parameters in real time through a smart contract: Node credibility: Based on historical behavior scores (such as shard call compliance, response latency); Attack frequency: The number of abnormal access requests detected per unit time; Cross-chain communication latency: The data synchronization time between the public chain and the consortium chain (threshold: ≤200ms); Automatically adjust the sharding parameters according to the risk level R: Low risk (R ≤ 0.3): The number of shards n = 3, the recombination threshold k = 2; Sharding storage location: 60% of the shards are stored in the public chain, and 40% are stored in the consortium chain; Medium risk (0.3 < R ≤ 0.7): n = 5, k = 3, and 50% of the shards are stored in each of the public chain and the consortium chain; High risk (R > 0.7): n = 7, k = 4, and 30% of the shards are stored in the public chain, and 70% are stored in the consortium chain; Sharding rule formula: ; Where n represents the number of shards; k represents the minimum number of shards required to recombine the key; R represents the network risk level.

[0019] When using the Shamir secret sharing algorithm to shard the key , double encryption is introduced: The first layer of encryption: For each shard ; The second layer of encryption: Bind with the current position coordinates of the UAV (GPS data) to generate the final shard ; Allocate the sharding storage location according to the risk level: The public chain nodes store (Example: IPFS network); The consortium chain nodes store (Hyperledger Fabric Private Channel); The shard stores metadata (shard ID, storage location), which is recorded and encrypted by the smart contract; When the drone needs to establish communication with the ground station, it submits to the smart contract: digital signatures of both parties (based on the ECDSA algorithm); the current GPS coordinates (used to decrypt the shard); The smart contract verifies: the validity of the signature; Whether the deviation between the GPS coordinates and the coordinates at the time of shard storage is within the allowable range (≤10km). The smart contract retrieves valid shards (not marked as invalid) from the public chain and the consortium chain according to the metadata; If the number of available shards ≥ k, enter the recombination process; Otherwise, trigger key update (see the dynamic key update unit); For each shard Execute: Restore using k shards through the Shamir algorithm Periodic update: Force an update of the shard rule every 24 hours (even if R does not change); Event-driven update: Immediately trigger an update when the following events are detected: The number of failed shard calls > 3 times; The drone's position moves more than 100km; The credibility of the blockchain node drops by more than 20%; Generate a new shard rule (adjust n, k, and storage ratio); Mark the old shards as invalid, and store the new shards according to the rule.

[0020] The dynamic key update unit triggers key update based on the risk level, generates a new key using PBFT consensus, and transmits the shard through a quantum-resistant channel; When the drone and the ground station initiate a communication request, they submit the following information to the blockchain network: Digital signature: The signatures of both parties based on the ECDSA algorithm to verify the legality of the identity; Real-time risk level R1: Obtain the current network risk level (such as the proportion of malicious nodes, attack frequency) from the blockchain network; The smart contract performs double verification, including identity verification: Check the validity of the signature to ensure that both parties are legal devices; Risk level threshold judgment: When R1 ≥ 0.5 (medium to high risk), trigger a forced key update; When R1 < 0.5, only trigger periodic update when the communication interval exceeds the set time; At the same time, adjust the number of PBFT consensus nodes according to the real-time risk level R1. When R1 < 0.3, 3 nodes participate in the consensus; When R1 ≥ 0.3, 7 nodes participate in the consensus; The nodes in the consensus group need to meet: The historical credibility score ≥ 80%; The physical locations are dispersed (to avoid physical attacks on nodes in a single area); The consensus group generates a new key through the PBFT algorithm ; Specific process: Proposal stage: The primary node generates a random number seed and broadcasts it to other nodes; Verification stage: The nodes verify the legality of the seed and generate ; Key sharding: Adopt a dynamic sharding strategy (see the key generation unit), and adjust the number of shards n and the threshold k according to R; The new key shards are transmitted to the UAV and the ground station through a quantum-secure channel (QKD): Sharded data encryption: Use the NTRU quantum-resistant encryption algorithm to protect the transmission process; Dynamic selection of transmission path: Select the optimal blockchain node path based on real-time network latency.

[0021] The key destruction and traceability unit is used to invalidate the key shards after the communication ends, and combines machine learning and blockchain logs to achieve anomaly detection and traceability; After the UAV completes the communication task, it sends an encryption termination instruction to the blockchain network, including: communication session ID (hash value), current key version number, and dual digital signatures (ECDSA) of the UAV and the ground station; The smart contract performs the following operations: Associated shard retrieval: Locate all associated key shards (including shards stored on the public chain and the consortium chain) based on the session ID and key version number; Shard status update: Mark the shards as "invalid" status and write them to the blockchain (recording the invalidation timestamp); Storage isolation: The invalid shards remain on the chain but are moved to a read-only storage area, prohibiting any call operations; The smart contract monitors the following metrics in real time: Shard call frequency: The number of shard calls per unit time (threshold: ≤3 times / minute); Access source IP: Detect node access from unconventional geographical locations (such as a sudden increase in overseas IPs); Node behavior pattern: Identify abnormal behaviors (abnormal shard call timing) through a machine learning model; Classify different abnormal events and trigger responses according to different threat levels, including: Low-level anomalies (such as a single frequency overrun): Record logs and do not alarm for the time being; Medium-level anomalies (such as abnormal IP address + frequency overrun): Freeze the shard call permission and notify the administrator; High-level anomalies (such as shard recombination failure accompanied by high-frequency access): Determine it as an attack and trigger an emergency key destruction; For abnormal node localization, combine the node registration information stored in the blockchain to locate the physical device corresponding to the abnormal IP, extract the transaction hash, digital signature, and timestamp of the abnormal operation, and generate an immutable forensic report; At the same time, the smart contract automatically executes: Add the abnormal node to the blacklist, prohibit it from participating in subsequent consensus or shard storage; Trigger the key update unit to immediately generate a new key to replace the attacked key; Push an alarm message (including a summary of the forensic report) to the security center.

[0022] The multi-band sensing and interference recognition unit is used to scan the multi-band spectrum in real time, use lightweight CNN to classify the interference types, and optimize the model through online learning; The drone is equipped with a wide-band spectrum scanning chip (covering the L band of 1 - 2 GHz, the C band of 4 - 8 GHz, and the Ku band of 12 - 18 GHz), scanning the spectrum once every 10 ms; collecting signal strength and noise power parameters for each frequency band; applying wavelet transform (Daubechies4 wavelet basis) to the original spectrum data to filter out environmental background noise; generating a spectrum feature matrix, including: peak frequency, bandwidth, instantaneous power change rate; frequency domain entropy (measuring spectrum complexity); using a pre-trained lightweight CNN model (structure: input layer [128x128 spectrogram], 3 convolutional layers + 2 fully connected layers) to perform interference classification: Input standardization: Normalize the spectrum data to the range of [-1, 1]; Interference type determination: Narrowband interference: The output probability > 0.8 and satisfies the following conditions: main lobe width < 5 MHz, peak power > -70 dBm; instantaneous power change rate > 10 dB / ms (conforming to radar pulse characteristics); Wideband noise interference: The output probability > 0.7 and satisfies: spectrum flatness > 0.9 (standard deviation < 2 dB); frequency domain entropy > 6.0 (high randomness); Interference intensity quantization: Divide into levels according to the signal-to-noise ratio (SNR): low intensity (SNR < 10 dB), medium intensity (10 dB ≤ SNR ≤ 20 dB), high intensity (SNR > 20 dB); Incremental training: If an unknown interference pattern is detected (CNN confidence < 0.6), trigger the following process: Collect new spectrum data and label it (assisted by manual review or rule engine); perform model fine-tuning on the edge computing unit (such as the FPGA on the drone side) to update the convolution kernel weights; synchronize the new model parameters to the blockchain network for other drone nodes to download and verify; Interference result output and response: Generate an interference map, construct a spatio-temporal interference heat map, including: interference type, intensity, and duration for each frequency band; possible directions of interference sources (through multi-drone collaborative spectrum direction finding); the heat map is uploaded to the ground command center through an encrypted channel; trigger real-time anti-interference strategies, generate control commands according to the recognition results: Narrowband interference: Trigger the dynamic frequency band switching unit to hop to an interference-free sub-band; Wideband interference: Trigger the multi-band cooperative transmission unit to start redundant coding (such as Turbo code); High-intensity interference: Enable the decoy signal emission module to attract enemy interference resources; The spectrum scanning chip adopts electromagnetic shielding packaging to prevent external injected interference; built-in self-checking circuit, regularly calibrating the ADC sampling accuracy (error < ±0.5 dB); if the scanned data is abnormal for 3 consecutive times (such as full-band saturation), switch to the backup spectrum database (storing historical clean spectrum templates).

[0023] The joint control unit is used to dynamically switch frequency bands, adjust power according to interference intensity and energy efficiency requirements, and enable beamforming to enhance anti-interception capabilities; Synchronously obtain the following data: Spectrum status: interference type (narrowband / wideband), intensity level (low / medium / high) from the multi-band sensing unit; Channel quality: bit error rate (BER), signal-to-noise ratio (SNR) feedback from the receiving end; Environmental parameters: communication distance d (through GPS or laser ranging), center frequency f of the current frequency band; Generate a spectrum-power joint decision matrix, weight allocation table 1:

[0024] Table 1 The frequency band selection and transmission mode switching process is as follows: Primary frequency band dynamic election: Frequency band scoring model: score of each frequency band ; where S is the frequency band score; SNR is the signal-to-noise ratio; Select the frequency band with the highest score as the main channel (e.g., Ku band), if its interference intensity exceeds the threshold (-90dBm), sequentially enable the standby frequency bands (C band → L band); Multi-band cooperative transmission activation: The trigger condition is: interference intensity of all frequency bands > -85dBm and BER > 1e-4; Data segmentation and coding: Divide the data packet into 3 sub-streams (each of the L / C / Ku bands carries 1 sub-stream); Add Reed-Solomon(255,223) redundant coding to each sub-stream, which can correct up to 16 bytes of errors; Parallel transmission: Synchronously transmit three sub-streams through software-defined radio (SDR); Adaptive power-beam collaborative control is as follows: Dynamic power calculation: Free space loss compensation: According to the formula Calculate the theoretical loss; where L represents the free space loss; d represents the communication distance; λ represents the signal wavelength; Dynamically adjust the transmission power according to the loss value L to keep the received power above -80dBm; When the interference intensity > -80dBm and the stealth requirement level ≥ 2 (special mission mode), obtain the target direction angle (based on the ground station GPS coordinates) through the phased array antenna; Calculate the beam pointing angle θ, and adjust the phase of the array elements to align the main lobe with the receiving end; Generate a null in the interference direction to suppress the reception of interference signals (depth ≥ 20dB).

[0025] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments only. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A secure communication system for an unmanned aerial vehicle, characterized in that, Including: A key generation and distributed storage unit that generates dynamic keys through a chaotic algorithm, combines blockchain sharding storage and GPS-bound encryption to achieve secure key distribution and anti-attack storage; A dynamic key update unit that triggers key updates based on risk levels, generates new keys using PBFT consensus, and transmits shards through a quantum-resistant channel; A key destruction and traceability unit that invalidates key shards after communication ends, and combines machine learning and blockchain logs to achieve anomaly detection and traceability; A multi-band sensing and interference recognition unit that scans the multi-band spectrum in real time, classifies interference types using lightweight CNN, and optimizes the model through online learning; A joint regulation unit that dynamically switches frequencies, adjusts power according to interference intensity and energy efficiency requirements, and enables beamforming to enhance anti-interception capabilities.

2. The secure communication system of an unmanned aerial vehicle according to claim 1, characterized in that, The execution process of the key generation and distributed storage unit is as follows: Generate a random key seed using the chaotic sequence algorithm and generate the initial key in combination with the unique identification code of the drone ; Encrypt using a hashing algorithm to generate the final key ; Use the Shamir secret sharing algorithm to split it into n shards, store the shards in multiple nodes of the blockchain network; and use a dynamic sharding strategy to adaptively adjust the number of shards; When using the Shamir secret sharing algorithm to fragment the key double encryption is introduced: First - layer encryption: For each shard ; Second - layer encryption: Bind with the current position coordinates of the drone to generate the final shard ; Allocate shard storage locations according to risk levels: public chain node storage ; consortium chain node storage ; the shard storage metadata includes the shard ID and the storage location, which are recorded and encrypted by the smart contract; When the drone needs to establish communication with the ground station, it submits to the smart contract: the digital signatures of both parties; the current GPS coordinates for decrypting the shards; the smart contract verifies: the validity of the signature; whether the deviation between the GPS coordinates and the coordinates at the time of shard storage is within the allowable range, and the allowable deviation range is ≤10km; The smart contract retrieves valid shards from the public chain and the consortium chain according to the metadata; if the number of available shards ≥ k, it enters the recombination process; Conversely, trigger key update; for each shard Execute: Restore using k shards through the Shamir algorithm ; Periodic update: Force an update of the sharding rules every 24 hours, even if R has not changed; Event-driven update: Immediately trigger an update when the following events are detected: the number of shard call failures > 3 times; the drone's position moves more than 100km; the credibility of the blockchain node drops by more than 20%; Generate new sharding rules; Mark the old shards as invalid, and store the new shards according to the rules again.

3. The secure communication system of an unmanned aerial vehicle according to claim 2, characterized in that, The specific process of the dynamic sharding strategy is as follows: Evaluate the network risk level R by collecting the following parameters in real time through the smart contract: Node credibility: Based on historical behavior scores, including shard call compliance and response latency; Attack frequency: The number of abnormal access requests detected per unit time; Cross-chain communication latency: The data synchronization time between the public chain and the consortium chain; Automatically adjust the sharding parameters according to the risk level R, and the process is as follows: When the risk level R ≤ 0.3, it is judged as a low risk, then the number of shards n = 3, and the recombination threshold k = 2; 60% of the shards are stored in the public chain and 40% are stored in the consortium chain for the shard storage location; When the risk level 0.3 < R ≤ 0.7, it is judged as a medium risk, then n = 5, k = 3, and 50% of the shards are stored in each of the public chain and the consortium chain; When the risk level R > 0.7, it is judged as a high risk, n = 7, k = 4, and 30% of the shards are stored in the public chain and 70% are stored in the consortium chain; Sharding rule formula: ; where n represents the number of shards; k represents the minimum number of shards required to reconstruct the key; R represents the network risk level.

4. The secure communication system for an unmanned aerial vehicle according to claim 1, characterized in that, The specific operation steps of the dynamic key update unit are as follows: When the drone and the ground station initiate a communication request, they submit the following information to the blockchain network: Digital signature: The signatures of both parties based on the ECDSA algorithm to verify the legitimacy of the identity; Real-time risk level R1: Obtain the current network risk level R1 from the blockchain network and analyze it through the malicious node ratio and attack frequency; The smart contract performs dual verification, including identity verification: checking the signature validity to ensure that both parties are legitimate devices; risk level threshold judgment: when R1≥0.5, trigger forced key update; When R1<0.5, trigger periodic update only when the communication interval exceeds the set time; At the same time, adjust the number of PBFT consensus nodes according to the real-time risk level R1. When R1<0.3, 3 nodes participate in the consensus; when R1≥0.3, 7 nodes participate in the consensus; the nodes in the consensus group need to meet the historical credibility score≥80% and be physically dispersed; The consensus group generates a new key through the PBFT algorithm ; Specific process: Proposal stage: The primary node generates a random number seed and broadcasts it to other nodes; Verification stage: The node verifies the legality of the seed and generates it after passing the vote ; Key sharding: Adopt a dynamic sharding strategy, and adjust the number of shards n and the threshold k according to R; The new key shards are transmitted to the UAV and the ground station through a quantum-secure channel: Sharded data encryption: Use the NTRU quantum-resistant encryption algorithm to protect the transmission process; Dynamic selection of the transmission path: Select the optimal blockchain node path according to the real-time network latency.

5. The secure communication system of an unmanned aerial vehicle according to claim 1, characterized in that The specific operation steps of the key destruction and traceability unit are as follows: After the UAV completes the communication task, it sends an encrypted termination instruction to the blockchain network, including: the communication session ID, i.e., the hash value, the current key version number, and the dual digital signatures of the UAV and the ground station; The smart contract performs the following operations: Associated shard retrieval: Locate all associated key shards according to the session ID and the key version number; Shard status update: Mark the shards as invalid status and write them into the blockchain; Storage isolation: The invalid shards remain on the chain but are moved to the read-only storage area, and any call operations are prohibited; The smart contract monitors the following metrics in real time: Shard call frequency: The number of shard calls per unit time; Access source IP: Detect node access from unconventional geographical locations; Node behavior pattern: Identify abnormal behaviors including abnormal shard call timing through a machine learning model; Classify different abnormal events and trigger responses according to different threat levels, including: Low-level anomaly: Record the log and do not alarm temporarily; Medium-level anomaly: Freeze the shard call permission and notify the administrator; High-level anomaly: Determine it as an attack and trigger emergency key destruction; For abnormal node location, combine the node registration information stored in the blockchain to locate the physical device corresponding to the abnormal IP, extract the transaction hash, digital signature, and timestamp of the abnormal operation, and generate an immutable forensic report; At the same time, the smart contract is automatically executed, including adding the abnormal node to the blacklist, prohibiting it from participating in subsequent consensus or shard storage, and triggering the key update unit to immediately generate a new key to replace the attacked key, and push an alarm message to the security center.

6. The secure communication system of an unmanned aerial vehicle according to claim 1, characterized in that The specific operation steps of the multi-band sensing and interference identification unit are as follows: The UAV is equipped with a wide-band spectrum scanning chip, which covers the L band of 1-2 GHz, the C band of 4-8 GHz, and the Ku band of 12-18 GHz, and scans the spectrum every 10 ms; Collect the signal strength and noise power parameters of each frequency band; Apply wavelet transform to the original spectrum data to filter out the environmental background noise; Generate Spectrum feature matrix, including: peak frequency, bandwidth, instantaneous power change rate; frequency domain entropy; Perform interference classification using a pre-trained lightweight CNN model. The specific structure of the pre-trained lightweight CNN model is an input layer [128x128 spectrogram], 3 convolutional layers + 2 fully connected layers: Input normalization: Normalize the spectral data to the range [-1, 1]; Interference type determination: Narrowband interference: Output probability > 0.8 and meet the following conditions: Main lobe width < 5 MHz, peak power > -70 dBm; Instantaneous power change rate > 10 dB / ms; Wideband noise interference: Output probability > 0.7 and meet: Spectral flatness > 0.9, and standard deviation < 2 dB; Frequency domain entropy > 6.0; Interference intensity quantization: Divide into levels according to the signal-to-noise power ratio: Low intensity is SNR < 10 dB, medium intensity is 10 dB ≤ SNR ≤ 20 dB, and high intensity is SNR > 20 dB; Incremental training: If an unknown interference pattern is detected, that is, the CNN confidence < 0.6, trigger the following process: Collect new spectral data and label it, specifically through manual review or assisted by a rule engine; Perform model fine-tuning on the edge computing unit to update the convolutional kernel weights; Synchronize the new model parameters to the blockchain network for other drone nodes to download and verify; The interference result output and response process is as follows: Generate an interference map, construct a spatio-temporal interference heat map, including: Interference type, intensity, and duration of each frequency band; Interference source azimuth; The heat map is uploaded to the ground command center through an encrypted channel; Trigger real-time anti-interference strategies, generate control commands according to the recognition results: Narrowband interference: Trigger the dynamic frequency band switching unit to hop to an interference-free sub-band; Wideband interference: Trigger the multi-band cooperative transmission unit to start redundant coding; High-intensity interference: Enable the decoy signal emission module to attract enemy interference resources; The spectrum scanning chip is encapsulated with electromagnetic shielding to prevent external injected interference; Built-in self-checking circuit, regularly verify the ADC sampling accuracy; If the scanned data is abnormal for 3 consecutive times, switch to the backup spectrum database.

7. The secure communication system of an unmanned aerial vehicle according to claim 1, characterized in that, The specific operation steps of the joint regulation unit are as follows: Synchronously obtain the spectrum status, channel quality, and environmental parameters, and generate a spectrum-power joint decision matrix; The frequency band selection and transmission mode switching process is as follows: Primary frequency band dynamic election: Frequency band scoring model: Score of each frequency band ; where S is the frequency band score; SNR is the signal-to-noise ratio; Select the frequency band with the highest score as the primary channel. If its interference intensity exceeds the threshold of -90 dBm, enable the standby frequency bands in sequence, that is, the C band → the L band; Activation of multi-band cooperative transmission: The trigger condition is: Interference intensity of all frequency bands > -85 dBm and BER > 1e-4; Data segmentation and coding: Divide the data packet into 3 sub-streams, that is, each of the L-band, C-band, and Ku-band carries 1 sub-stream; Add Reed-Solomon redundant coding to each sub-stream; Parallel transmission: Synchronously transmit the three sub-streams through software-defined radio; The adaptive power-beam cooperative regulation process is as follows: Power dynamic calculation: Free space loss compensation: According to the formula calculate the theoretical loss; where L represents the free space loss; d represents the communication distance; λ represents the signal wavelength; dynamically adjust the transmit power according to the loss value L , so that the received power is maintained above -80 dBm; When the interference intensity > -80 dBm and the stealth requirement level ≥ 2, obtain the target direction angle through the phased array antenna; Calculate the beam pointing angle θ, adjust the phase of the array elements to align the main lobe with the receiving end; Generate a null in the interference direction to suppress the reception of interference signals.

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