A covert communication system and method based on cluster motion platform beam synthesis

Abstract

The application provides a concealed communication system and method based on cluster moving platform beam synthesis, the concealed communication system comprises: N source nodes, the source nodes are moving nodes, and the N source nodes form a cluster; one target node, the target node is a fixed communication node, and is used for cooperating with the N source nodes in the cluster to perform carrier and phase synchronization; the N source nodes and the target node are each provided with an antenna, each antenna is used as an array element unit antenna to form a linear array, a surface array or a curved surface array; after the carriers and phases of the source nodes in the cluster are synchronized, the antennas are arrayed, and a beam is synthesized to point to the target node, the application can reach N 2 times the power of a single node (p) in a specified communication direction, so that the communication distance and the communication capability are greatly improved, and the whole system has good concealed communication capability, anti-destruction and robustness.

Description

[Technical Field]

[0001] This invention relates to the field of wireless communication technology, and in particular to a covert communication system and method based on clustered dynamic platform beamforming. [Background Technology]

[0002] To achieve covert communication capabilities in wireless communication and reduce the risk of being detected and interfering with other communication systems, techniques such as low-power spectrum waveform design, spatially divided directional communication, and efficient power and transceiver control are commonly employed.

[0003] In space-division directional covert communication, the most common approach is to use multi-antenna phased array technology to form directional beams for communication, achieving concealment and reducing interference to the surrounding environment and systems. However, a drawback is that since multiple antennas (assuming N antennas) are located on a single node / platform (UAV / unmanned vehicle / unmanned boat / etc.), the power (p) of each platform is limited. Therefore, even after forming a directional beam through the antenna array, the power in the pointing direction is also very limited (N*p), resulting in limited communication distance and capability. For long-distance communication, the power of a single node / platform must be increased, which is usually not feasible. Furthermore, all signal power is output from a large node platform. Besides the large platform's large size and lack of concealment, if the large platform fails or is damaged, the entire system fails, lacking robustness and resilience.

[0004] Placing N antennas on N nodes / platforms solves the power limitation problem of a single node / platform, allowing full utilization of the power of all N nodes / platforms. Organizing multiple antennas on different platforms into a sparsely arranged, mobile antenna array, and combining beams to form a directional beam, can achieve N^2 times the power of a single node (p) in a specified communication direction, significantly improving communication distance and capability. Furthermore, using a mobile platform allows for flexible reconfiguration by changing the array formation as needed; the nodes in the array can also be moved and separated as required, causing the beam to disappear simultaneously, enhancing concealment. Even if individual nodes are destroyed, the remaining nodes can continue to adjust the array to maintain the beam. This makes the entire system more concealed, resistant to destruction, and robust against interference.

[0005] In the published patent CN 110635255 A, "A Three-Dimensional Array Antenna Based on a Swarm of UAVs," there are multiple nodes (multiple UAVs) in space. Each UAV is equipped with an antenna and a signal controller, with one UAV serving as the master UAV and the others as auxiliary UAVs. According to its specification (pages 2 and 3 both mention that "the master UAV is used to execute the following program: according to the instructions of the ground control system, it calculates the total antenna beam to be formed by the UAV array through an intelligent optimization algorithm, obtains the adjustment information of each auxiliary UAV, and compiles the adjustment information of each auxiliary UAV into a complete data packet; the adjustment information includes the speed, position, attitude of the UAV, and the amplitude and phase of the antenna on the UAV; the data packet is sent to each auxiliary UAV through a remote control link; the auxiliary UAV is used to execute the following program: obtain the adjustment information of its own UAV from the data packet; control its own UAV and its antenna according to the adjustment information"); and its workflow. Figure 3 (etc.) The patent does not perform time synchronization, carrier and phase synchronization between the various drones, which results in the signal of the synthesized total beam being incoherent at the receiving node, and the total power can only be increased by N times.

[0006] In addition, its working mechanism is to use the amplitude and phase of each element in the antenna array on the control auxiliary drone to form a sub-beam first, and then let these sub-beams form a composite beam in space. However, since there is no synchronization between the drones, it cannot guarantee the phase relationship when the signals of each drone reach the target communication node. It is an incoherent beam synthesis, and its total power can only be increased by a maximum of N times. (On pages 3-4 of the specification, “

[0025] The signal sent by the main UAV to the auxiliary UAV should include the speed, position, attitude of the UAV calculated by intelligent optimization algorithms such as genetic algorithms or neural networks, as well as the amplitude and phase of the antenna. After receiving this information, each auxiliary UAV adjusts its own speed, position, and attitude. This information serves as the basis for the adjustment of the antenna beam direction on each auxiliary UAV. Then, the amplitude and phase of the antenna are analyzed in the antenna array processor of each UAV and converted into the amplitude and phase of the onboard antenna beam. The antenna on each auxiliary UAV forms an antenna beam that meets the requirements in a specific direction in accordance with the predetermined requirements of the main UAV. These antenna beams then form a specific composite beam in space.”)

[0007] Therefore, it is necessary to study a covert communication system and method based on clustered dynamic platform beamforming to address the shortcomings of existing technologies and solve or mitigate one or more of the above-mentioned problems. [Summary of the Invention]

[0008] In view of this, the present invention provides a covert communication system and method based on clustered dynamic platform beamforming, which can achieve N in a specified communication direction. 2 The power of a single node (p) is doubled, thereby significantly improving communication distance and capability. In addition, the use of a dynamic platform allows for easy adjustment and reconfiguration of the array formation as needed, enabling different antenna arrays with high flexibility. Furthermore, the nodes in the array can be moved and separated as needed, and the beam disappears simultaneously, enhancing concealment. Moreover, even if individual nodes are destroyed, the remaining nodes can continue to adjust the array formation to maintain the beam, making the entire system more concealed, resistant to destruction, and robust against interference.

[0009] On one hand, the present invention provides a covert communication system based on clustered dynamic platform beamforming, the covert communication system comprising:

[0010] There are N source nodes, which are motion nodes, and the N source nodes form a cluster;

[0011] A target node, which is a fixed communication node, is used to coordinate with N source nodes in the cluster for carrier and phase synchronization.

[0012] N source nodes and one target node are each equipped with an antenna. Each antenna is used as an array element antenna to form a linear array, a surface array, or a curved array.

[0013] After the carrier and phase of each source node in the cluster are synchronized, the antennas are arrayed and the combined beam is directed towards the target node.

[0014] In addition to the aspects and any possible implementations described above, a further implementation is provided in which each of the N source nodes and one target node includes:

[0015] The radio frequency front-end module is fixedly installed on N source nodes and / or target nodes;

[0016] Radio frequency transceiver module, used to receive and transmit radio frequency signals;

[0017] The synchronization calculation module is used to synchronize the cluster with carrier and phase, and to calculate the sparse array position of the antennas.

[0018] As described above and in any possible implementation, a further implementation is provided, wherein the synchronous computing module includes:

[0019] Amplitude and phase adjustment processing unit, used to adjust the amplitude and phase of each source node;

[0020] The carrier synchronization processing unit is used to synchronize the carriers of each source node.

[0021] The phase synchronization processing unit is used to synchronize the phases of each source node.

[0022] The node attitude adjustment and control unit is used to adjust and control the attitude of each source node;

[0023] The node position adjustment and control unit is used to adjust and control the position of each source node;

[0024] The sparse array position calculation unit is used to calculate and optimize the position of the sparse array composed of antennas on each source node.

[0025] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the method for the target node to cooperate with N source nodes in the cluster to perform carrier and phase synchronization includes, but is not limited to, time slot round-trip carrier synchronization and feedback synchronization.

[0026] In addition to the aspects described above and any possible implementation, a further implementation is provided in which the spacing between the source nodes is greater than the operating wavelength.

[0027] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the sparse array is optimized by: calculating the optimized position arrangement of the entire array using a genetic algorithm or a particle swarm optimization algorithm to form an optimized sparse array, wherein the grating lobes of the sparse array are optimized and eliminated.

[0028] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the amplitude and phase adjustment is specifically performed by applying amplitude and phase weighting to each source node through Chebyshev or Taylor expansion, thereby increasing the principal-to-side ratio and reducing external interference.

[0029] In addition to the aspects described above and any possible implementation, a further implementation is provided in which the N source nodes exchange information via a preset protocol.

[0030] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the physical objects mounted on the source node and the target node include, but are not limited to, drones.

[0031] In accordance with the aspects and any possible implementations described above, a covert communication method based on clustered dynamic platform beamforming is further provided, which is accomplished through the aforementioned covert communication system. The covert communication method includes the following steps:

[0032] S1: Adjust the position and orientation of the source nodes by calculating the sparse array position to form a cluster node array;

[0033] S2: The target node sends a beacon to the source node, and the source node performs carrier and phase adjustments; phase calculation;

[0034] S3: Source nodes exchange signals round trip and adjust amplitude and phase;

[0035] S4: The source node synthesizes a beam and transmits the signal to the target node.

[0036] Compared with the prior art, the present invention can achieve the following technical effects:

[0037] (1) This invention solves the problem that when communicating over long distances, it is necessary to increase the power of a single carrier platform, which is usually impossible (due to increased power consumption, size, and weight). The power of multiple platforms can be combined into a directional beam through space.

[0038] (2) The present invention solves the shortcomings of lack of robustness and resistance to destruction. That is, when the signal power of all antenna units is output by a large platform node, the large platform itself lacks concealment. On the other hand, once the large platform fails or is damaged, the entire communication system will also fail.

[0039] (3) The present invention solves the problem of coherent power synthesis, thereby allowing the synthesized power and the number of clusters to grow exponentially instead of linearly.

[0040] Of course, any product implementing this invention does not necessarily need to achieve all of the technical effects described above at the same time. [Attached Image Description]

[0041] To more clearly illustrate the technical solutions of the embodiments of the present invention, 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.

[0042] Figure 1 This is a system overall block diagram provided in one embodiment of the present invention;

[0043] Figure 2 This is a hardware structure diagram of each node provided in one embodiment of the present invention;

[0044] Figure 3 This is a system workflow diagram provided in one embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram of a node time synchronization scheme provided in one embodiment of the present invention;

[0046] Figure 5 This invention provides a method for generating a large number of grating lobe patterns when using 64 nodes with a spacing of 5 times the wavelength, as provided in one embodiment.

[0047] Figure 6This is a composite beam (grating lobe elimination) diagram with 64 nodes and a 5-times wavelength spacing optimized by an algorithm according to an embodiment of the present invention;

[0048] Figure 7 This is a magnified view of a synthesized beam with a 64-node, 5-times-wavelength spacing optimized by an algorithm, provided in one embodiment of the present invention.

[0049] Figure 8 This is a graph of synthesized beam gain and duration (16 nodes, 900MHz, signal-to-noise ratio 10dB) provided in one embodiment of the present invention;

[0050] Figure 9 This is a diagram showing the amplitude of a coherent beamforming signal versus the amplitude of an incoherent beamforming signal, provided in one embodiment of the present invention.

Detailed Implementation Methods

[0051] To better understand the technical solution of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0052] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0053] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0054] This invention provides a covert communication system and method based on clustered dynamic platform beamforming, the covert communication system comprising:

[0055] There are N source nodes, which are motion nodes, and the N source nodes form a cluster;

[0056] A target node, which is a fixed communication node, is used to coordinate with N source nodes in the cluster for carrier and phase synchronization.

[0057] N source nodes and one target node are each equipped with an antenna. Each antenna is used as an array element antenna to form a linear array, a surface array, or a curved array.

[0058] After the carrier and phase of each source node in the cluster are synchronized, the antennas are arrayed and the combined beam is directed towards the target node.

[0059] The N source nodes and one target node each include:

[0060] The radio frequency front-end module is fixedly installed on N source nodes and / or target nodes;

[0061] Radio frequency transceiver module, used to receive and transmit radio frequency signals;

[0062] The synchronization calculation module is used to synchronize the cluster with carrier and phase, and to calculate the sparse array position of the antennas.

[0063] The synchronous computing module includes:

[0064] Amplitude and phase adjustment processing unit, used to adjust the amplitude and phase of each source node;

[0065] The carrier synchronization processing unit is used to synchronize the carriers of each source node.

[0066] The phase synchronization processing unit is used to synchronize the phases of each source node.

[0067] The node attitude adjustment and control unit is used to adjust and control the attitude of each source node;

[0068] The node position adjustment and control unit is used to adjust and control the position of each source node;

[0069] The sparse array position calculation unit is used to calculate and optimize the position of the sparse array composed of antennas on each source node.

[0070] The method for the target node to coordinate with N source nodes in the cluster to perform carrier and phase synchronization includes, but is not limited to, time-slot round-trip carrier synchronization and feedback synchronization.

[0071] The spacing between each source node is greater than the operating wavelength.

[0072] The optimization of the sparse array specifically involves: calculating the optimal positional arrangement of the entire array using genetic algorithms and particle swarm optimization algorithms to form an optimized sparse array, in which the grating lobes of the sparse array are optimized and eliminated.

[0073] The amplitude and phase adjustment specifically involves applying amplitude and phase weights to each source node using Chebyshev or Taylor expansion to increase the principal-to-side ratio and reduce external interference.

[0074] The N source nodes exchange information via a preset protocol.

[0075] The physical devices carried by the source node and the target node include, but are not limited to, drones.

[0076] This invention also provides a covert communication method based on clustered dynamic platform beamforming, which is implemented through the aforementioned covert communication system. The covert communication method includes the following steps:

[0077] S1: Adjust the position and orientation of the source nodes by calculating the sparse array position to form a cluster node array;

[0078] S2: The target node sends a beacon to the source node, and the source node performs carrier and phase adjustments; phase calculation;

[0079] S3: Source nodes exchange signals round trip and adjust amplitude and phase;

[0080] S4: The source node synthesizes a beam and transmits the signal to the target node.

[0081] S1 specifically includes:

[0082] S11: Sparse array position calculation;

[0083] S12: Cluster node position adjustment;

[0084] S13: Cluster node attitude control;

[0085] S14: Cluster node array formation;

[0086] S2 specifically includes:

[0087] S21: The target node sends a beacon;

[0088] S22: Source node receives beacon;

[0089] S23: Source node carrier calculation;

[0090] S24: Source node phase calculation;

[0091] S3 specifically includes:

[0092] S31: Calculation of carrier phase of round-trip interactive signal from source node;

[0093] S32: The source node performs amplitude and phase adjustment.

[0094] This invention employs a cluster of moving nodes. Utilizing the coordinated cooperation of target nodes, it achieves carrier and phase synchronization of the cluster's moving nodes through methods such as time-slot round-trip carrier synchronization and feedback synchronization, rather than traditional satellite navigation clock synchronization or time synchronization technologies like GPS / BeiDou / GLONASS (which cannot achieve synchronization of the cluster signal carrier-level frequency and phase). Based on this, antennas on each node (omnidirectional / directional, single / multiple antennas) are used as array element antennas to form linear / area / curved arrays, etc. Unlike traditional phased array antennas where the spacing is less than one wavelength, the spacing between the moving platform nodes in this system is typically greater than, or even much greater than, the operating wavelength, forming a sparse array, such as... Figure 5As shown, sparse antenna arrays have a large number of grating lobes, which cause energy dispersion and severely weaken the power of the synthesized beam. Therefore, genetic algorithms and particle algorithms are used to optimize the position of each node in the cluster to eliminate grating lobes. The results are as follows. Figure 6 and Figure 7 As shown; after the carrier and phase of each node in the cluster are synchronized, the optimized cluster node positions are used to form an array, and the synthesized beam is directed towards the target communication node, as shown. Figure 8 As shown, the signals from each node are coherently superimposed at the target node with the same frequency and phase, achieving a power gain of N^2 times, thus realizing high-gain communication. Furthermore, by using Chebyshev and Taylor expansion methods to weight the amplitude and phase of each node, the principal-to-side ratio is increased, external interference is reduced, and the concealment of the communication is improved. Moreover, by employing mobile platform arrays (aircraft, vehicles, ships, etc.), the independent mobility of each node allows for fragmentation and beam disappearance when separated, resulting in high concealment; when combined, they form a directional beam gain to complete the communication task, while each node does not require high power, saving power and reducing weight and volume. In addition, the flexible array configuration allows for rapid re-arraying even if some nodes are damaged, without affecting the overall system's synthesized beam and operation. Therefore, the entire system possesses better concealed communication capabilities, resistance to destruction, and robustness.

[0095] Example 1:

[0096] The key technologies involved in this invention include beamforming of the cluster dynamic platform, sparse arraying, grating lobe elimination algorithm, cluster node time synchronization, and cluster networking.

[0097] 1. System Description

[0098] Figure 1 The diagram shows the entire cluster covert communication system, which consists of n source nodes and one target node. The cluster composite beam formed by the n source nodes points towards the target node, completing directional covert communication and suppressing interference from other directions.

[0099] 2. Node Hardware Structure

[0100] Regardless of the source node or the target node, the hardware configuration of each node is as follows: Figure 2 As shown, each node consists of a sparse array position calculation module, node position adjustment control, node attitude adjustment control, carrier synchronization processing, phase synchronization processing, amplitude and phase adjustment processing, RF transceiver module, RF lead-ahead module, and antenna.

[0101] 3. System Workflow Description

[0102] (1) As Figure 3As shown, firstly, one node in the specified source node cluster is initialized as the master node. The sparse array position calculation module of the master node calculates the optimized position arrangement of the entire array using position optimization methods such as genetic algorithms and particle swarm optimization, forming an optimized sparse array in which the grating lobes are optimized and eliminated. Then, the optimized position information of each node is sent out.

[0103] (2) Each node receives its own position information and adjusts its position through the control structure.

[0104] (3) Each node adjusts its attitude (heading angle / pitch angle / roll angle, etc.) through the control structure to maintain the correct angle.

[0105] (4) The source node group forms the calculated sparse array formation.

[0106] (5) The target node broadcasts a beacon to the source node group.

[0107] (6) All source nodes receive the beacon and use the carrier synchronization and phase synchronization processing modules to calculate the carrier frequency of the received signal.

[0108] (7) All source nodes receive the beacon, and after carrier synchronization, the phase synchronization processing module calculates the carrier phase of the received signal.

[0109] (8) Source nodes exchange and send information to each other according to a certain protocol, such as Figure 4 Schematic diagram of time synchronization schemes (including but not limited to this scheme)

[0110] (9) All source nodes calculate their respective received carrier frequencies and phases, and synthesize synchronized carrier frequencies and phases in a certain manner.

[0111] (10) The amplitude and phase adjustment module uses Chebyshev and Taylor expansion methods to perform amplitude and phase weighting on each node, which increases the principal-to-side ratio, reduces external interference, and improves the concealment of communication.

[0112] (11) All source nodes transmit the same information to the target node using a synthesized carrier frequency and phase. The signals received by the target node from each source node are coherently superimposed at the same frequency and phase, resulting in a waveform amplitude increase of N times (e.g., ...). Figure 9 As shown), the power gain reaches N^2, and the synthesized beam from the source node group is directed towards the target node for covert communication. The duration of the synthesized beam is as follows: Figure 8 (16 nodes, 900MHz, signal-to-noise ratio 10dB), gain drop of less than 1dB within 150us.

[0113] Compared to traditional antenna array technology, this invention solves the problem that it is usually impossible to increase the power of a single carrier platform for long-distance communication (due to increased power consumption, size, and weight). It can combine the power of multiple platforms into a directional beam through space.

[0114] Compared to traditional antenna array technology, this invention solves the shortcomings of lacking robustness and resilience. That is, when the signal power of all antenna elements is output by a large platform node, the large platform itself lacks concealment, and if the large platform fails or is damaged, the entire communication system will also fail.

[0115] Compared to previous technologies (patent CN 110635255 A A three-dimensional array antenna based on UAV swarms), this invention solves the problem of coherent power combining, thereby allowing the combined power to grow exponentially with the number of swarm members instead of linearly. Figure 9 As shown, when the amplitude of the 64-node sine wave is 1, the amplitude of the synthesized waveform can reach 64, and the synthesized power increases by 64*64=4096 times, while the amplitude and power of the random synthesized waveform are very low.

[0116] In summary, a covert communication system and method based on clustered moving platform beamforming solves the problem of coherent superposition of signals from each node at the target node using carrier and phase synchronization, achieving a power gain of N^2 times and realizing high gain. It also addresses the issue of grating lobes formed when the spacing between moving platforms is much larger than the operating wavelength, which is beneficial for focusing and synthesizing the power and gain of the beam. Furthermore, it solves the problem of insufficient total power and weak survivability and robustness when the array antenna is mounted on a single platform. By suppressing sidelobe interference, it reduces interference outside the communication direction, further improving concealment. The system allows for flexible arraying of moving platforms (aircraft, vehicles, ships, etc.), with each node being independently movable. When separated, the beam and communication disappear; when combined, they form a directional beam gain to complete the communication task. Each node does not require high power, saving power and reducing weight and volume. The array configuration is flexible and adaptable. Even if some nodes are damaged, the system can be quickly reassembled without affecting beamforming and operation, giving the entire system better covert communication capabilities, survivability, and robustness.

[0117] The foregoing has provided a detailed description of a covert communication system and method based on beamforming of a clustered dynamic platform, as provided in the embodiments of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and its core ideas; furthermore, those skilled in the art will recognize that, based on the ideas of this application, 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 this application.

[0118] Certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The terms "comprising" and "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising / including but not limited to". "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error. The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of illustrating the general principles of this application and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0119] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0120] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0121] The foregoing description illustrates and describes several preferred embodiments of this application. However, as previously stated, it should be understood that this application is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the application concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this application should be within the protection scope of the appended claims.

Claims

1. A covert communication system based on clustered dynamic platform beamforming, characterized in that, The covert communication system includes: There are N source nodes, which are motion nodes, and the N source nodes form a cluster; A target node, which is a fixed communication node, is used to coordinate with N source nodes in the cluster for carrier and phase synchronization. N source nodes and one target node are each equipped with an antenna. Each antenna is used as an array element antenna to form a linear array, a surface array, or a curved array. After the carrier and phase of each source node in the cluster are synchronized, the antennas are arrayed to synthesize a beam pointing towards the target node; The N source nodes and one target node each include: The radio frequency front-end module is fixedly installed on N source nodes and / or target nodes; Radio frequency transceiver module, used to receive and transmit radio frequency signals; The synchronization calculation module is used to perform carrier and phase synchronization on the cluster, and to calculate the sparse array positions of the antennas. The synchronous computing module includes: Amplitude and phase adjustment processing unit, used to adjust the amplitude and phase of each source node; The carrier synchronization processing unit is used to synchronize the carriers of each source node. The phase synchronization processing unit is used to synchronize the phases of each source node. The node attitude adjustment and control unit is used to adjust and control the attitude of each source node; The node position adjustment and control unit is used to adjust and control the position of each source node; The sparse array position calculation unit is used to calculate and optimize the position of the sparse array composed of antennas on each source node; The method for the target node to coordinate with N source nodes in the cluster to perform carrier and phase synchronization includes, but is not limited to, time-slot round-trip carrier synchronization and feedback synchronization. The spacing between each source node is greater than the operating wavelength.

2. The covert communication system according to claim 1, characterized in that, The optimization of the sparse array specifically involves: calculating the optimal positional arrangement of the entire array using a genetic algorithm and a particle swarm optimization algorithm to form an optimized sparse array, in which the grating lobes of the sparse array are optimized and eliminated.

3. The covert communication system according to claim 1, characterized in that, The amplitude and phase adjustment specifically involves applying amplitude and phase weights to each source node using Chebyshev or Taylor expansion to increase the principal-to-side ratio and reduce external interference.

4. The covert communication system according to claim 1, characterized in that, The N source nodes exchange information via a preset protocol.

5. The covert communication system according to claim 1, characterized in that, The physical devices carried by the source node and the target node include, but are not limited to, drones.

6. A covert communication method based on clustered dynamic platform beamforming, implemented using the covert communication system described in any one of claims 1-5, characterized in that, The covert communication method includes the following steps: S1: Adjust the position and orientation of the source nodes by calculating the sparse array position to form a cluster node array; S2: The target node sends a beacon to the source node, and the source node performs carrier and phase adjustments; phase calculation; S3: Source nodes exchange signals round trip and adjust amplitude and phase; S4: The source node synthesizes a beam and transmits the signal to the target node.

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