A cooperative method for low-altitude electromagnetic spectrum suppression regions with access keys

Abstract

This invention provides a collaborative method for low-altitude electromagnetic spectrum suppression areas with a communication key. The method includes developing a communication key, using the key to suppress key low-altitude areas across the entire frequency band, constructing a dedicated channel, and camouflaging the dedicated channel with noise. Security drones communicate with the security control system and other security drones within the dedicated channel using the communication key and artificial noise sequences. This invention enables security drones to achieve covert and reliable collaborative communication under full-band suppression, while effectively denying the communication capabilities of intruding drones. Its dynamic key mechanism ensures communication security, and noise injection ensures channel covertness. This scheme significantly improves communication support and collaborative combat capabilities for low-altitude security missions in complex electromagnetic environments, and has significant practical value.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic spectrum countermeasures technology, and in particular to a collaborative method for suppressing low-altitude electromagnetic spectrum regions with a pass key. Background Technology

[0002] In the electromagnetic environment of key protected low-altitude airspace, high-power electromagnetic suppression equipment suppresses the entire frequency band, rendering any drone controlled and coordinated via wireless communication inoperable. When the intruder uses fiber-optic drones or fully autonomous drones that do not require manual operation, the security drones cannot operate under electromagnetic suppression. If the security drones also employ fiber-optic communication and autonomous countermeasures, the imbalance in the size and complexity of the operational airspace between the security and intruder forces makes it difficult for the security team to achieve large-scale coverage of the key protected low-altitude airspace and engage in high-intensity countermeasures against the intruder drones. Therefore, designing a coordinated method for low-altitude electromagnetic spectrum suppression with a communication key is essential. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the purpose of this invention is to provide a collaborative method for low-altitude electromagnetic spectrum suppression regions with a pass key.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] This invention provides a collaborative method for low-altitude electromagnetic spectrum suppression regions with a access key, comprising:

[0006] Step 1: Create a pass key;

[0007] Step 2: Combine the access key to perform full-band suppression of the key protected low-altitude airspace and construct a dedicated channel;

[0008] Step 3: Noise camouflage of the dedicated channel;

[0009] Step 4: The security drone communicates with the security control system and other security drones via a dedicated channel using a pass key and an artificial noise sequence.

[0010] Preferably, the access key is a access window table consisting of consecutive time window-frequency band window pairs, wherein the time window length, frequency band window width, and position of each time window-frequency band window pair are random.

[0011] Preferably, in step 1, the access key is generated as follows:

[0012] The frequency band for obtaining the communication key is used to determine the time window-frequency band window pair, where the parameters of each window include the start time of the time window, the center frequency of the frequency band, the length of the time window, and the bandwidth of the frequency band.

[0013] A pseudo-random number generator is used to generate window parameters, and the time window length and frequency band bandwidth are obtained through linear mapping.

[0014] The time window length is normalized, and the start time of the time window is calculated recursively.

[0015] The center frequency of the frequency band is obtained by uniformly distributing it within the available spectrum.

[0016] Preferably, in step 2, the key protected low-altitude airspace is suppressed across the entire frequency band using the access key to construct a dedicated channel, specifically as follows:

[0017] By employing high-power electromagnetic suppression equipment, comprehensive suppression is carried out in all frequency bands outside the corresponding frequency band window according to each time window, thereby realizing the construction of a dynamic frequency hopping dedicated channel.

[0018] Preferably, in step 3, noise masquerading is performed on the dedicated channel, specifically as follows:

[0019] The power spectral density of the artificial noise is designed to be consistent with the suppression region, and a time-domain signal of the artificial noise is constructed.

[0020] When the security personnel transmit the original communication signal through the dedicated channel, they superimpose artificial noise into the time-domain signal;

[0021] The security receiver acquires the received signal and recovers the original communication signal by subtracting the known artificial noise from the time-domain signal.

[0022] Preferably, the power spectral density of the artificial noise is designed to be consistent with the suppression region to construct the time-domain signal of the artificial noise, specifically as follows:

[0023] The power spectral density of the artificial noise is designed to be consistent with the suppression region, as follows:

[0024] (1)

[0025] In the formula, The power suppressed per unit bandwidth is f, where f is the frequency. For dedicated channels, To achieve a flat noise spectrum, the constructed artificial noise time-domain signal is as follows:

[0026] (2)

[0027] In the formula, For noise frequency components, The number of frequency components, The amplitude is a Gaussian random amplitude. Let be the starting frequency of the frequency band in the i-th window, and t be the time. For the bandwidth of the i-th frequency band, It is a uniformly distributed random phase.

[0028] Preferably, when the security provider transmits the original communication signal through the dedicated channel, it superimposes an artificial noise time-domain signal, specifically as follows:

[0029] The security provider is using a dedicated channel. Send raw communication signals At that time, the artificial noise time-domain signal is superimposed to obtain the transmitted signal, which is:

[0030] (3).

[0031] Preferably, the security receiver acquires the received signal and recovers the original communication signal by subtracting the known artificial noise time-domain signal, specifically as follows:

[0032] The security receiver has a known artificial noise sequence. The received signal is:

[0033] (4)

[0034] in The original communication signal is recovered by subtracting known artificial noise from the channel noise, as follows:

[0035] (5).

[0036] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0037] This invention provides a collaborative method for low-altitude electromagnetic spectrum suppression regions with a communication key. The method includes: compiling a communication key; using the communication key to suppress key low-altitude areas across the entire frequency band; constructing a dedicated channel; masquerading the dedicated channel with noise; and enabling security drones to communicate with the security control system and other security drones within the dedicated channel using the communication key and an artificial noise sequence. The significant advantages of this invention are reflected in multiple aspects:

[0038] First, this method innovatively solves the core problem of communication interruption of security drones in the suppression area by constructing a dedicated channel with dynamic frequency hopping in a strong electromagnetic suppression environment. Compared with the existing technology, this invention does not simply avoid suppression, but cleverly uses the suppression environment itself to create communication conditions that are favorable to oneself, realizing a strategic shift from "passive obstruction" to "active utilization".

[0039] Secondly, by introducing a sophisticated noise camouflage mechanism, this method ensures the ultimate concealment of the dedicated channel. Injecting artificial noise with characteristics highly consistent with surrounding suppressed signals into the dedicated channel makes the entire spectrum exhibit uniform, strong interference characteristics under external observation, effectively masking the communication "backdoor." This design greatly increases the difficulty for intruders to discover and utilize the channel through spectrum analysis, thus ensuring uninterrupted communication for their own side while strictly denying the enemy drone's communication capabilities, forming an asymmetric communication advantage.

[0040] Furthermore, this method possesses high intelligence and environmental adaptability. The dynamic access key generated by the pseudo-random algorithm causes the time and frequency position of the dedicated channel to change continuously, avoiding the security risks that may be caused by the fixed pattern. By sharing the key and noise sequence, the security drone swarm can achieve accurate time and frequency synchronization and reliable collaborative communication in complex electromagnetic environments, supporting the completion of large-scale and highly complex swarm combat missions.

[0041] Finally, the solution boasts excellent practicality and compatibility. Its communication frequency band strictly adheres to the radio management regulations for civil unmanned aerial vehicles, ensuring the compliance and feasibility of the technology. The entire system requires no major modifications to the UAV hardware, primarily achieving functionality through key management and signal processing algorithms. It has low deployment costs and is easy to integrate into existing security systems, providing an efficient, reliable, and low-cost solution for the protection of key low-altitude airspaces. This significantly improves the effectiveness and success rate of public safety operations in complex electromagnetic environments. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of the method flow of the present invention. Detailed Implementation

[0044] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] The purpose of this invention is to provide a collaborative method for low-altitude electromagnetic spectrum suppression regions with a communication key, enabling security drones to achieve covert and reliable collaborative communication under full-band suppression, while effectively denying the communication capabilities of intruding drones. Its dynamic key mechanism ensures communication security, and noise injection ensures channel covertness. This scheme significantly improves the communication support and collaborative combat capabilities of low-altitude security missions in complex electromagnetic environments, and has important practical value.

[0046] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] like Figure 1 As shown, this invention provides a cooperative method for low-altitude electromagnetic spectrum suppression regions with a access key, comprising:

[0048] Step 1: Create a pass key;

[0049] Step 2: Combine the access key to perform full-band suppression of the key protected low-altitude airspace and construct a dedicated channel;

[0050] Step 3: Noise camouflage of the dedicated channel;

[0051] Step 4: The security drone communicates with the security control system and other security drones via a dedicated channel using a pass key and an artificial noise sequence.

[0052] The access key is a access window table composed of consecutive time window-frequency band window pairs. During the compilation phase, the time window length, frequency band window width, and position of each time window-frequency band window pair are randomized. An appropriate number of time window-frequency band window pairs fill a period of appropriate length. By periodically repeating the access window table, the system determines the spatiotemporal location of the cooperating security party and denies the intruder's dynamic frequency hopping private channel.

[0053] In step 1, the access key is generated, specifically as follows:

[0054] According to the "Interim Measures for Radio Management of Civil Unmanned Aerial Vehicles," radio stations for civil unmanned aerial vehicle communication systems that achieve remote control, telemetry, and information transmission functions through direct communication should use all or some of the following frequencies: 1430-1444MHz, 2400-2476MHz, and 5725-5829MHz. Frequency bands for electromagnetic suppression and access keys also appear within these specified frequency bands.

[0055] Taking 5725-5829MHz as an example, this invention sets the minimum key frequency limit. Maximum frequency limit A time period is (seconds), the communication key is defined as a time-frequency window pair sequence. , of which window , Let i be the starting time of the i-th time window. Let i be the starting frequency of the frequency band in the i-th window. and These represent the length of the i-th time window and the bandwidth of the i-th frequency band, respectively.

[0056] Window parameters are generated using a linear congruent pseudo-random number generator:

[0057] (1)

[0058] in For standard parameters, The key seed (a positive integer);

[0059] Normalize the generated pseudo-random numbers to From the interval, we get:

[0060] (2)

[0061] The time window length and frequency band bandwidth are obtained through linear mapping, and the duration of the i-th time window is... and the bandwidth of the i-th window The calculation method is as follows:

[0062] (4)

[0063] in This is the minimum duration of the time window, with a reference value of 1 second. This is the maximum duration of the time window, with a reference value of 5 seconds. This is a normalized random number used to calculate the duration of the i-th window; This is the minimum bandwidth of the frequency band, fixed at 10MHz. The maximum value of the frequency band bandwidth is:

[0064]

[0065] To ensure that the time windows are continuous and non-overlapping, normalization is performed; the start time of the time window is recursively calculated as follows:

[0066] (5)

[0067] (6)

[0068] The starting frequency of the i-th window is calculated as follows:

[0069] (7)

[0070] Where is the normalized random number used for calculating the frequency position of the i-th window.

[0071] In step 2, the key protected low-altitude airspace is suppressed across the entire frequency band using the access key to construct a dedicated channel, specifically as follows:

[0072] High-power electromagnetic suppression equipment is used to comprehensively suppress other frequency bands outside the corresponding frequency band window according to each time window, so as to realize the construction of dynamic frequency hopping dedicated channel;

[0073] At any moment Define the protected frequency band (i.e., the dedicated channel). The power spectral density distribution of the suppressed signal is as follows:

[0074] (8)

[0075] in, Suppression power per unit bandwidth Let f be the frequency weighting function, and f be the frequency, then:

[0076] (9)

[0077] The edge enhancement coefficient, To enhance suppression at the guard band edges and prevent spectrum leakage, this design is designed to extend the frequency range.

[0078] The time-domain expression for the suppression signal is:

[0079] (10)

[0080] in For each frequency component, the random phase. This refers to the frequency resolution.

[0081] In step 3, noise masquerading is performed on the dedicated channel, specifically as follows:

[0082] The power spectral density of the artificial noise is designed to be consistent with the suppression region, and a time-domain signal of the artificial noise is constructed.

[0083] When the security personnel transmit the original communication signal through the dedicated channel, they superimpose artificial noise into the time-domain signal;

[0084] The security receiver acquires the received signal and recovers the original communication signal by subtracting the known artificial noise time-domain signal.

[0085] This step will be explained in detail:

[0086] To prevent intruders from discovering "silent" regions (i.e., dedicated channels) in the suppressed spectrum through spectrum analysis. Artificial noise with characteristics consistent with the suppressed signal is injected into the dedicated channel, and the power spectral density of the artificial noise is designed to be consistent with the suppression region, as follows:

[0087] (11)

[0088] In the formula, To achieve a flat noise spectrum, the constructed artificial noise time-domain signal is as follows:

[0089] (12)

[0090] In the formula, Here, t represents the noise frequency component, and t represents time. The number of frequency components, The amplitude is a Gaussian random amplitude. The phase is a uniformly distributed random phase;

[0091] The signal encoding at the transmitting end involves superimposing artificial noise time-domain signals onto the original communication signals transmitted by the security party through a dedicated channel. Specifically:

[0092] The security provider is using a dedicated channel. Send raw communication signals At that time, the artificial noise time-domain signal is superimposed to obtain the transmitted signal, which is:

[0093] (13)

[0094] Signal recovery at the receiving end; the security receiver has a known artificial noise sequence. The received signal is:

[0095] (14)

[0096] in The original signal is recovered by subtracting known artificial noise from the channel noise, as follows:

[0097] (15)

[0098] The power spectral density exhibits uniformity across the entire frequency band, as follows:

[0099] (16)

[0100] in, The power spectral density of the communication signal, when viewed from the outside, shows a uniform strong interference characteristic across the entire spectrum, completely concealing the proprietary channel.

[0101] In step 4, the security drone communicates with the security control system and other security drones via a dedicated channel using a pass key and an artificial noise sequence. Specifically:

[0102] Security drone swarms share access keys and artificial noise sequences In the Time window Inside, drones Frequency band used The transmitted signal has the following modulated signal:

[0103] (17)

[0104] in, For transmission power, For baseband information signals, This is the initial phase;

[0105] Transmitted signal after adding artificial noise:

[0106] (18)

[0107] drones The received signal in the dedicated channel is:

[0108] (19)

[0109] in For drones To drones The channel fading coefficient, To delay the transmission time, Channel noise;

[0110] drones The signal is recovered by subtracting known artificial noise:

[0111] (20)

[0112] The baseband signal is obtained after demodulation:

[0113] (twenty one)

[0114] in Indicates a low-pass filter;

[0115] Communication quality is determined by the signal-to-noise ratio:

[0116] (twenty two)

[0117] in For signal power, This represents channel noise power. Due to artificial noise... It is completely eliminated at the receiving end and does not affect the communication quality;

[0118] Time and frequency synchronization requirements:

[0119] (twenty three)

[0120] Using the above scheme, the system establishes a concealed, proprietary communication channel under full-band suppression. Intruding drones are unable to communicate normally within the suppression area, while the security team can communicate via a shared access key. With artificial noise sequences, reliable communication can be achieved within dynamically changing proprietary channels. The injection of artificial noise makes the proprietary channels indistinguishable in the spectrum, effectively preventing intruders from discovering and exploiting these "backdoor" frequency bands. Ultimately, it enables operation and coordination within the heavily protected low-altitude electromagnetic suppression environment, achieving the capability to support all-space operations and the execution of highly complex tasks.

[0121] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0122] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A collaborative method for low-altitude electromagnetic spectrum suppression regions with a access key, characterized in that, include: Step 1: Create a pass key; Step 2: Combine the access key to perform full-band suppression of the key protected low-altitude airspace and construct a dedicated channel; Step 3: Noise camouflage of the dedicated channel; specifically: The power spectral density of the artificial noise is designed to be consistent with the suppression region, and a time-domain signal of the artificial noise is constructed. When the security personnel transmit the original communication signal through the dedicated channel, they superimpose artificial noise into the time-domain signal; The security receiver acquires the received signal and recovers the original communication signal by subtracting the known artificial noise time-domain signal. The power spectral density of the artificial noise is designed to be consistent with the suppression region, and the time-domain signal of the artificial noise is constructed as follows: The power spectral density of the artificial noise is designed to be consistent with the suppression region, as follows: （1） In the formula, The power suppressed per unit bandwidth is f, where f is the frequency. For dedicated channels, To achieve a flat noise spectrum, the constructed artificial noise time-domain signal is as follows: （2） In the formula, For noise frequency components, The number of frequency components, The amplitude is a Gaussian random amplitude. Let be the starting frequency of the frequency band in the i-th window, and t be the time. For the bandwidth of the i-th frequency band, The phase is a uniformly distributed random phase; When the security provider transmits the original communication signal through the dedicated channel, it superimposes artificial noise into the time-domain signal, specifically as follows: The security provider is using a dedicated channel. Send raw communication signals At that time, the artificial noise time-domain signal is superimposed to obtain the transmitted signal, which is: （3） The security receiver acquires the received signal and recovers the original communication signal by subtracting the known artificial noise time-domain signal. Specifically: The security receiver has known artificial noise time-domain signal. The received signal is: （4） in The original communication signal is recovered by subtracting the known artificial noise from the time-domain signal, which is the channel noise. （5） Step 4: The security drone communicates with the security control system and other security drones via a dedicated channel using a pass key and an artificial noise sequence.

2. The method according to claim 1, characterized in that, The access key is a access window table consisting of consecutive time window-frequency band window pairs, wherein the time window length, frequency band window width, and position of each time window-frequency band window pair are random.

3. The method according to claim 2, characterized in that, In step 1, the access key is generated, specifically as follows: The frequency band for obtaining the communication key is used to determine the time window-frequency band window pair, where the parameters of each window include the start time of the time window, the center frequency of the frequency band, the length of the time window, and the bandwidth of the frequency band. A pseudo-random number generator is used to generate window parameters, and the time window length and frequency band bandwidth are obtained through linear mapping. The time window length is normalized, and the start time of the time window is calculated recursively. The center frequency of the frequency band is obtained by uniformly distributing it within the available spectrum.

4. The method according to claim 3, characterized in that, In step 2, the key protected low-altitude airspace is suppressed across the entire frequency band using the access key to construct a dedicated channel, specifically as follows: By employing high-power electromagnetic suppression equipment, comprehensive suppression is carried out in all frequency bands outside the corresponding frequency band window according to each time window, thereby realizing the construction of a dynamic frequency hopping dedicated channel.

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