A link evaluation method for flying self-organizing networks

Abstract

The present invention relates to the field of wireless communication technology and specifically discloses a link evaluation method for a flying ad hoc network. The method comprises: constructing an antenna model, a transmitter model, a receiver model, and an interference model; determining a topology structure based on the true and deviated positions of any two communication nodes in the flying ad hoc network; determining corresponding antennas based on the true and deviated positions of any two communication nodes in the topology structure, and obtaining antenna gain based on the antennas and antenna patterns in the antenna model; determining link loss, received signal power, and interference power based on the transmitter model, the receiver model, and the interference model, and calculating a signal-to-noise ratio based on the link loss, received signal power, and interference power; and determining a bit error rate based on the signal-to-noise ratio and the state of the flying ad hoc network, thereby evaluating the flying ad hoc network based on the signal-to-noise ratio and bit error rate. The method can be used to analyze the impact of navigation deviation on link performance and help optimize flying ad hoc network protocols.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a link evaluation method for a flying self-organizing network. Background Art

[0002] Self-organizing flight networks are a crucial foundation for enabling the dynamic and rapid networking of aircraft swarms in the air and building collaborative networked systems. They have been widely used in drone swarms, aerospace, and air traffic management systems. Aircraft nodes exchange data in real time via wireless links, automatically identifying changes in network topology (such as new nodes, node failures, or relocations), dynamically adjusting communication paths, and autonomously constructing a decentralized communication network, enabling rapid information transmission and sharing.

[0003] With the continuous development and improvement of aircraft network collaboration and autonomous capabilities, existing networking technologies face the following challenges:

[0004] First, nodes move at high speeds, and link status is highly variable. Nodes in flying ad hoc networks move at high speeds, and network topology changes frequently. Link quality is affected by a variety of factors, such as flight altitude, speed, weather conditions, and geographical environment. Link quality fluctuates significantly, making it difficult for the traditional static, single-source link quality models currently used in flying ad hoc networks to accurately assess and predict link status.

[0005] Second, frequent network ingress and egress lead to highly dynamic topology. Aircraft nodes move quickly, change directions, and frequently enter and exit the network, resulting in highly dynamic network topology, which can easily lead to increased transmission link interruption rates and decreased network service quality.

[0006] An analysis of current research at home and abroad reveals that traditional evaluation methods, based on the parameters selected for highly dynamic, high-speed topologies in three-dimensional space, are inadequate for comprehensive link evaluation. These methods typically estimate links based on ideal conditions and lack methods that consider link quality calculations in the presence of navigation errors. Consequently, they are unable to comprehensively and accurately assess network link quality. In the presence of navigation errors, network nodes communicating using directional or phased array antennas struggle to accurately select the appropriate antenna or beam. Traditional link calculations can lead to inaccurate results, impacting network stability and reliability. Summary of the Invention

[0007] In response to the above problems, the purpose of the present invention is to provide a link evaluation method for a flight self-organizing network, construct a wireless link model based on the directional communication characteristics of the flight self-organizing network, and realize the ability to comprehensively and accurately calculate the link quality in real application scenarios. It can be used to analyze the impact of navigation deviation on link performance and help optimize the flight self-organizing network protocol.

[0008] The present invention provides a link evaluation method for a flying self-organizing network, wherein the flying self-organizing network includes a plurality of communication nodes and links between the communication nodes; the link evaluation method includes:

[0009] Obtaining the node parameters of the communication node, the true position of the communication node in the Earth-centered Earth-fixed coordinate system, and the deviation position of the communication node including the navigation deviation;

[0010] Build antenna models, transmitter models, receiver models, and interference models;

[0011] Determining a topological structure of the flight self-organizing network according to the true postures and deviation postures of any two communication nodes in the flight self-organizing network;

[0012] Determining corresponding antennas according to the actual postures and the deviation postures of any two communication nodes in the topology structure, and obtaining antenna gains according to the antennas and the antenna patterns in the antenna model;

[0013] Determining link loss, received signal power, and interference power respectively according to the transmitter model, the receiver model, and the interference model, and calculating a signal-to-noise ratio according to the link loss, the received signal power, and the interference power;

[0014] A bit error rate is determined according to the signal-to-noise ratio and the state of the flying ad hoc network, so as to evaluate the flying ad hoc network according to the signal-to-noise ratio and the bit error rate.

[0015] In a possible implementation, determining the topology of the flight self-organizing network according to the true poses and the deviation poses of any two communication nodes in the flight self-organizing network includes:

[0016] Determine and calculate the three-dimensional coordinates and communication reachability of any two communication nodes in the flight self-organizing network according to their true poses and deviation poses:

[0017] When communication between the two communication nodes is unreachable, stopping link evaluation and determining that the link quality status between the communication nodes is 0;

[0018] When communication between the two communication nodes is reachable, it is determined that a link exists between the two communication nodes; and a plurality of the links constitute the topology structure.

[0019] In one possible implementation, determining corresponding antennas according to the actual postures and the deviation postures of any two communication nodes in the topology structure, and obtaining antenna gains according to the antennas and the antenna patterns in the antenna model includes:

[0020] Determine all true angles between the communication vector and the normal of each antenna according to the true positions of any two communication nodes in the topological structure, and determine the true antenna according to the direction vector corresponding to the minimum true angle;

[0021] Determine all deviation angles between the communication vector and the normal of each antenna according to the deviation postures of any two communication nodes in the topology structure, and determine the deviation antenna according to the direction vector corresponding to the minimum deviation angle;

[0022] When the real antenna and the deviation antenna are inconsistent, the link evaluation is stopped, and the link quality state between the communication nodes is determined to be 0;

[0023] When the real antenna and the deviation antenna are consistent, the actual angle between the communication vector and the antenna normal is determined according to the real posture and deviation posture of any two communication nodes in the topology structure, and the antenna radiation pattern in the antenna model is searched according to the actual angle to obtain the transmitting / receiving antenna gain.

[0024] In a possible implementation, the communication node includes a source node and a destination node; and further includes:

[0025] Calculate the coordinate transformation matrix from the Earth-centered Earth-fixed coordinate system to the aircraft coordinate system based on the attitude information of the source node;

[0026] The position coordinates of the source node and the destination node are converted into the aircraft coordinate system according to the coordinate conversion matrix, and the coordinate vectors of the source node and the destination node are calculated;

[0027] The true angle or the deviation angle is calculated according to the coordinate vector and the antenna normal.

[0028] In a possible implementation, converting the position coordinates of the source node and the destination node into an aircraft coordinate system according to the coordinate conversion matrix includes:

[0029] Convert the position coordinates of the source and destination nodes to the aircraft coordinate system according to the following formula:

[0030] ;

[0031] ;

[0032] Where, is the coordinate transformation matrix, is the coordinate of the source node in the Earth-centered Earth-fixed coordinate system, is the coordinate of the source node in the aircraft coordinate system, is the coordinate of the destination node in the Earth-centered Earth-fixed coordinate system, is the coordinate of the destination node in the aircraft coordinate system;

[0033] The calculation of the coordinate vectors of the source node and the destination node includes:

[0034] Calculate the coordinate vectors of the source and destination nodes according to the following formula :

[0035] ;

[0036] Where, is the coordinate vector;

[0037] Calculating the true angle or the deviation angle according to the coordinate vector and the antenna normal includes:

[0038] The true angle or deviation angle is calculated according to the following formula :

[0039] ;

[0040] Where, is the direction vector of a certain antenna normal, is the coordinate vector of the communication target.

[0041] In a possible implementation manner, the bit error rate is calculated according to the signal-to-noise ratio.

[0042] In a possible implementation, the interference model supports a suppression interference scenario; the input of the interference model is a fixed received power or a dynamically superimposed received power of multiple interference sources.

[0043] In a possible implementation, determining the bit error rate according to the signal-to-noise ratio and the state of the flight ad hoc network includes:

[0044] When the state of the flight ad hoc network is offline, generating a lookup table of bit error rate and frame error rate;

[0045] When the state of the flight self-organizing network is online, the lookup table is dynamically called according to the topology structure and the navigation deviation to obtain the link quality state.

[0046] In a possible implementation, the link loss includes path loss, atmospheric attenuation loss, and polarization loss.

[0047] In a possible implementation, the node parameters include: node antenna type, beam pointing parameters, transmit power, modulation mode, receive sensitivity, and noise figure.

[0048] The link evaluation method for the flight self-organizing network provided by the present invention can be used for simulation before the flight mission to fully evaluate the impact of navigation deviation, and can guide the improvement of the flight self-organizing network protocol algorithm, thereby enhancing the stability and communication efficiency of the network to meet the needs of strong and reliable networking of highly dynamic aircraft clusters. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of a link evaluation method according to an embodiment of the present invention;

[0050] Figure 2 A topological diagram of a flight ad hoc network provided by an embodiment of the present invention;

[0051] Figure 3 A schematic diagram of directional communication in a flying ad hoc network according to an embodiment of the present invention;

[0052] Figure 4 A schematic diagram illustrating the impact of navigation deviation on directional antenna selection and beam pointing provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0053] The following detailed description of the embodiments of the present invention is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are intended to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention. That is, the present invention is not limited to the preferred embodiments described, and the scope of the present invention is defined by the claims.

[0054] In the description of the present invention, it should be noted that, unless otherwise specified, “plurality” means two or more; the terms “first”, “second”, etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0055] Figure 1 A schematic diagram of a link evaluation method according to an embodiment of the present invention is shown in FIG. Figure 1 As shown, the present invention provides a link evaluation method for a flying self-organizing network, wherein the flying self-organizing network includes a plurality of communication nodes and links between the communication nodes; the link evaluation method includes:

[0056] Step S1, obtaining node parameters of the communication node, the true position of the communication node in the Earth-centered Earth-fixed coordinate system, and the deviation position of the communication node including the navigation deviation;

[0057] In one possible implementation, node parameters characterize the configuration parameters and performance characteristics of each node device in the network topology. These parameters serve as fundamental parameters for model construction and algorithm deduction, and have a decisive impact on the overall system performance. True pose accurately describes the true spatial orientation of a communication node in a given reference coordinate system. Its mathematical representation typically uses quaternions or attitude angles for high-precision representation. Deviation pose represents the deviation in pose measurement during actual flight due to inherent errors in the navigation system.

[0058] Among them, node parameters include: node antenna type, beam pointing parameters, transmit power, modulation mode, receiving sensitivity and noise figure.

[0059] Step S2, constructing antenna model, transmitter model, receiver model and interference model;

[0060] In one possible implementation, communication nodes in an aircraft ad hoc network can be equipped with different types of antennas, including omnidirectional and directional antennas, as needed. In this specific implementation, antenna pattern data is pre-loaded in the form of a data file. Then, a table lookup is performed to retrieve the corresponding gain data from the database, and bilinear interpolation is performed to obtain the antenna gain value at any angle. Because navigation information deviations significantly impact directional communication, this invention primarily considers directional antenna models.

[0061] The antenna model of the present invention is used to describe the characteristics and performance of the antenna, including its installation position, antenna pattern, gain and other parameters. The antenna model of the present invention can use table lookup and bilinear interpolation to obtain the antenna gain at any angle.

[0062] The transmitter model describes the transmitter's output power, modulation scheme, and other characteristics. The transmitter model's processing includes: link layer data undergoes CRC checksum, data scrambling, encoding, channel interleaving, and modulation to obtain a baseband modulated signal. This signal is then subjected to spread spectrum hopping modulation and carrier modulation to output the RF signal.

[0063] The receiver model focuses on parameters such as receiver sensitivity and noise figure. The processing of the receiver model includes: carrier demodulation, spread spectrum hopping demodulation, demodulation, channel deinterleaving, decoding, data scrambling, and CRC check to obtain the receiving end information.

[0064] The interference model is used to simulate and analyze various interference sources that may exist in the network, including co-channel interference and adjacent-channel interference. The interference model supports suppression interference scenarios. The input to the interference model is a fixed received power or the dynamically superimposed received power of multiple interference sources. This refers to an interference method in which the interferer transmits an interference signal that simulates noise, causing the communication receiver to receive a high-power interference signal simultaneously with the communication signal, significantly reducing the signal-to-noise ratio of the received signal. During simulation operations, the interference model is called on demand based on the input parameter configuration information to calculate the transmitted interference signal power, signal frequency, signal bandwidth characteristics, and the signal power of the communication receiver.

[0065] Step S3, determining the topology of the flight self-organizing network according to the true posture and deviation posture of any two communication nodes in the flight self-organizing network; Figure 2 A topological diagram of a flight ad hoc network provided by an embodiment of the present invention;

[0066] In one possible implementation, topology calculation is a fundamental step in the link computation model. It involves determining the three-dimensional locations of all communicating nodes within a flying ad hoc network, taking into account factors such as node mobility, altitude, and flight trajectory. Accurately modeling the spatial distribution of nodes allows for a better understanding of the potential of communication links, which is crucial for predicting link performance.

[0067] In one possible implementation, the three-dimensional coordinates and communication reachability of any two communication nodes in the flight ad hoc network are determined and calculated based on their true poses and deviation poses:

[0068] When the communication between two communication nodes is unreachable, the link evaluation is stopped and the link quality status between the communication nodes is determined to be 0;

[0069] When communication between two communication nodes is reachable, it is determined that there is a link between the two communication nodes; multiple links form a topological structure.

[0070] In one example, the topology relationship calculation first converts the real position coordinates of the source node and the destination node into the Earth-centered Earth-fixed coordinate system, i.e., the source node (x1, y1, z1) and the destination node (x2, y2, z2). The Euclidean distance between the source node and the destination node is then calculated.

[0071] The Euclidean distance between the source node and the destination node is calculated according to the following formula: :

[0072] ;

[0073] Determine whether the Euclidean distance exceeds the designed maximum communicable distance. If so, stop subsequent calculations and set the node link quality status to 0. If not, proceed with subsequent calculations.

[0074] Step S4, determining the corresponding antennas according to the actual postures and deviation postures of any two communication nodes in the topology structure, and obtaining the antenna gain according to the antenna and the antenna pattern in the antenna model; Figure 3 A schematic diagram of directional communication in a flying ad hoc network according to an embodiment of the present invention;

[0075] In one possible implementation, determining corresponding antennas based on the actual positions and deviation positions of any two communication nodes in the topology, and obtaining antenna gains based on the antennas and antenna patterns in the antenna model include:

[0076] Determine all true angles between the communication vector and the normal of each antenna based on the true positions of any two communication nodes in the topology, and determine the true antenna based on the direction vector corresponding to the minimum true angle;

[0077] Determine all deviation angles between the communication vector and the normal direction of each antenna based on the deviation postures of any two communication nodes in the topology, and determine the deviation antenna based on the direction vector corresponding to the minimum deviation angle;

[0078] When the real antenna and the deviation antenna are inconsistent, the link evaluation is stopped and the link quality status between the communication nodes is determined to be 0;

[0079] When the real antenna and the deviation antenna are consistent, the actual angle between the communication vector and the antenna normal is determined according to the real posture and deviation posture of any two communication nodes in the topology structure, and the antenna radiation pattern in the antenna model is searched according to the actual angle to obtain the transmitting / receiving antenna gain.

[0080] In one example, the communication nodes include a source node and a destination node; a coordinate transformation matrix from an Earth-centered Earth-fixed coordinate system to an aircraft coordinate system is calculated based on the attitude information of the source node;

[0081] The position coordinates of the source node and the destination node are converted to the aircraft coordinate system according to the coordinate transformation matrix, and the coordinate vectors of the source node and the destination node are calculated;

[0082] Convert the position coordinates of the source and destination nodes to the aircraft coordinate system according to the following formula:

[0083] ;

[0084] ;

[0085] Where, is the coordinate transformation matrix, is the coordinate of the source node in the Earth-centered Earth-fixed coordinate system, is the coordinate of the source node in the aircraft coordinate system, is the coordinate of the destination node in the Earth-centered Earth-fixed coordinate system, is the coordinate of the destination node in the aircraft coordinate system;

[0086] Calculate the coordinate vectors of the source and destination nodes according to the following formula :

[0087] ;

[0088] Where, is the coordinate vector;

[0089] Calculate the true angle or deviation angle based on the coordinate vector and the antenna normal.

[0090] The true angle or deviation angle is calculated according to the following formula :

[0091] ;

[0092] Where, is the direction vector of a certain antenna normal, is the coordinate vector of the communication target.

[0093] Select the direction vector that maximizes the cosine angle, that is, minimizes the angle. The antenna to which it belongs is the selected real antenna m and deviation antenna n.

[0094] Determine whether the actual antenna and the deviation antenna are consistent. If m≠n, stop the subsequent calculation and set the node link quality status to 0. If m=n, continue the subsequent calculation, including calculating the actual transmit antenna gain and the actual receive antenna gain:

[0095] The transmission beam is determined using the information of the source node and the destination node containing navigation errors. Figure 4 As shown in the figure, the transmit beam selects beam position 4. The actual position is used to calculate the angle between the beam pointing direction and the center of beam position 4. Based on this angle, the actual transmit antenna gain is calculated by querying the antenna pattern.

[0096] The information of the source node and the destination node containing the navigation error is used to determine the beam where the receiving antenna is located. Figure 4 As shown in the figure, the receive beam is selected as beam 3. The angle between the beam pointing direction and the center of beam position 3 is calculated using the actual position. The actual receive antenna gain is calculated based on the angle by querying the antenna pattern.

[0097] Step S5, determining link loss, received signal power, and interference power based on the transmitter model, receiver model, and interference model, and calculating the signal-to-noise ratio based on the link loss, received signal power, and interference power;

[0098] In one possible implementation, based on typical mission requirements and scenarios, the default channel model is an additive white Gaussian noise channel. Different signal-to-noise ratios are used to calculate the bit error rate and frame error rate of inter-aircraft link communications, thereby completing the calculation and evaluation of link quality.

[0099] In one possible implementation, the link loss is calculated according to the following formula: :

[0100] ;

[0101] Where, is the signal wavelength, is the transmission distance.

[0102] The path loss is expressed in dB according to the following formula :

[0103] ;

[0104] In a possible implementation, the link loss includes path loss, atmospheric attenuation loss, and polarization loss.

[0105] The received signal power is calculated according to the following formula :

[0106] ;

[0107] Where, is the transmit power, is the receiving antenna directional gain, is the directional gain of the transmitting antenna, L is the link loss, is the receiving antenna direction angle, is the angle between the transmitting antenna and the direction of the transmitting antenna.

[0108] During simulation, the communication received signal power is compared with the receiver sensitivity. If the power is less than the sensitivity, the link is directly determined to be unavailable, and subsequent bit error rate and frame error rate analysis is not performed.

[0109] The interference power is calculated according to the following formula :

[0110] ;

[0111] Where, is the interference transmission power, is the interference antenna transmission direction gain, is the interference antenna receiving direction gain, is the link loss from the jammer to the receiver, To receive broadband, To transmit broadband.

[0112] If multiple jammers interfere with the same communication equipment, the interference power at the receiving antenna of the communication equipment is the superposition of multiple interference echo powers.

[0113] Calculate the receiver in-band background noise using the following formula:

[0114] ;

[0115] ;

[0116] Where K = 1.381ⅹ J / K, T is 290K, is the equivalent bandwidth of the receiver (HZ), is the noise figure (dB).

[0117] The signal-to-noise ratio is calculated according to the following formula :

[0118] ;

[0119] Where, is the interference power, is the received signal power, is the interference power.

[0120] Step S6: determining a bit error rate according to the signal-to-noise ratio and the state of the flight ad hoc network, so as to evaluate the flight ad hoc network according to the signal-to-noise ratio and the bit error rate.

[0121] In one possible implementation, when the state of the flight self-organizing network is offline, a lookup table of bit error rate and frame error rate is generated; when the state of the flight self-organizing network is online, the lookup table is dynamically called according to the topology structure and navigation deviation to obtain the link quality status.

[0122] Specifically, the CRC checksum, scrambling, channel coding, channel interleaving, modulation, and other aspects of the data transmission process, as well as the corresponding data reception process, were simulated using MATLAB tools to calculate the bit error rate (BER) under different communication rates, coding parameters, modulation parameters, and signal-to-noise ratios. A BER lookup table was then created and loaded into the link quality calculation. For the gain improvement achieved with spread spectrum technology, a reasonable additional gain was set by considering factors such as the spreading code length and spreading code rate. For the gain improvement achieved with frequency hopping technology, the calculation required considering the interference process.

[0123] In one possible implementation, the bit error rate and frame error rate calculation is based on establishing a bit error rate lookup table based on offline signal level simulation, and combining the current signal-to-noise ratio to obtain the bit error rate; the frame error rate is calculated based on the bit error rate and frame length.

[0124] Assuming that the link bit error rate probability distribution is binomial distribution, the relationship between the frame error rate PF and the bit error rate Pe is:

[0125] P F = 1 - (1 - P e ) N ;

[0126] Where N is the number of code elements in a frame.

[0127] In summary, positioning errors primarily affect link attenuation calculations and transmit and receive antenna gain calculations. Topology calculations determine the connectivity and topology between nodes in the network, providing a preliminary assessment of reachability between transmitting and receiving nodes. Beam alignment calculations calculate the direction of the antenna beam and obtain antenna gain by querying the antenna pattern. Signal-to-noise ratio calculations assess signal quality during transmission; a higher signal-to-noise ratio indicates better signal quality. Bit error rate calculations assess data transmission reliability; a lower bit error rate indicates higher reliability.

[0128] The link evaluation method for a flying self-organizing network provided by the present invention constructs a refined wireless link calculation process by rationally constructing a model and combining three-dimensional space topology calculation and dynamic interference environment simulation. The method comprehensively considers the influence of navigation deviation on the attenuation of the flying self-organizing network communication link and the directivity gain of the directional antenna, and integrates this into the link quality calculation process, thereby improving the accuracy and reliability of the link calculation. The method reduces the complexity of real-time calculation through a two-stage strategy of offline signal-level simulation and online function-level simulation, providing strong support for the optimized design, protocol development and resource allocation of the flying self-organizing network, and has greater engineering application potential and practical value.

[0129] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A link evaluation method for a flying self-organizing network, characterized in that: The flight self-organizing network includes a plurality of communication nodes and links between the communication nodes; the link evaluation method includes: Obtaining the node parameters of the communication node, the true position of the communication node in the Earth-centered Earth-fixed coordinate system, and the deviation position of the communication node including the navigation deviation; Build antenna models, transmitter models, receiver models, and interference models; Determining a topological structure of the flight self-organizing network according to the true postures and deviation postures of any two communication nodes in the flight self-organizing network; Determining corresponding antennas according to the actual postures and the deviation postures of any two communication nodes in the topology structure, and obtaining antenna gains according to the antennas and the antenna patterns in the antenna model; Determining link loss, received signal power, and interference power respectively according to the transmitter model, the receiver model, and the interference model, and calculating a signal-to-noise ratio according to the link loss, the received signal power, and the interference power; determining a bit error rate based on the signal-to-noise ratio and a state of the flight ad hoc network, for evaluating the flight ad hoc network based on the signal-to-noise ratio and the bit error rate; Determining the topology of the flight self-organizing network according to the true postures and deviation postures of any two communication nodes in the flight self-organizing network includes: Determine and calculate the three-dimensional coordinates and communication reachability of any two communication nodes in the flight self-organizing network according to their true poses and deviation poses: When communication between the two communication nodes is unreachable, stopping link evaluation and determining that the link quality status between the communication nodes is 0; When communication between the two communication nodes is reachable, determining that a link exists between the two communication nodes; a plurality of the links constitute the topology structure; The determining corresponding antennas according to the true postures and the deviation postures of any two communication nodes in the topological structure, and obtaining antenna gains according to the antennas and the antenna patterns in the antenna model includes: Determine all true angles between the communication vector and the normal of each antenna according to the true positions of any two communication nodes in the topological structure, and determine the true antenna according to the direction vector corresponding to the minimum true angle; Determine all deviation angles between the communication vector and the normal of each antenna according to the deviation postures of any two communication nodes in the topology structure, and determine the deviation antenna according to the direction vector corresponding to the minimum deviation angle; When the real antenna and the deviation antenna are inconsistent, the link evaluation is stopped, and the link quality state between the communication nodes is determined to be 0; When the real antenna and the deviation antenna are consistent, the actual angle between the communication vector and the antenna normal is determined according to the real posture and deviation posture of any two communication nodes in the topology structure, and the antenna radiation pattern in the antenna model is searched according to the actual angle to obtain the transmitting / receiving antenna gain.

2. The link evaluation method according to claim 1, wherein: The communication nodes include a source node and a destination node; and further include: Calculate the coordinate transformation matrix from the Earth-centered Earth-fixed coordinate system to the aircraft coordinate system based on the attitude information of the source node; The position coordinates of the source node and the destination node are converted into the aircraft coordinate system according to the coordinate conversion matrix, and the coordinate vectors of the source node and the destination node are calculated; The true angle or the deviation angle is calculated according to the coordinate vector and the antenna normal.

3. The link evaluation method according to claim 2, wherein: The converting the position coordinates of the source node and the destination node into the aircraft coordinate system according to the coordinate conversion matrix includes: Convert the position coordinates of the source and destination nodes to the aircraft coordinate system according to the following formula: Where, is the coordinate transformation matrix, is the coordinate of the source node in the Earth-centered Earth-fixed coordinate system, is the coordinate of the source node in the aircraft coordinate system, is the coordinate of the destination node in the Earth-centered Earth-fixed coordinate system, is the coordinate of the destination node in the aircraft coordinate system; The calculation of the coordinate vectors of the source node and the destination node includes: Calculate the coordinate vectors of the source and destination nodes according to the following formula Where, (Δx (B) ,Δy (B) ,Δz (B) ) is the coordinate vector; Calculating the true angle or the deviation angle according to the coordinate vector and the antenna normal includes: The true angle or deviation angle is calculated according to the following formula Where, is the direction vector of a certain antenna normal, is the coordinate vector of the communication target.

4. The link evaluation method according to claim 1, wherein: The bit error rate is calculated according to the signal-to-noise ratio.

5. The link evaluation method according to claim 1, wherein: The interference model supports suppression interference scenarios; the input of the interference model is a fixed received power or a dynamically superimposed received power of multiple interference sources.

6. The link evaluation method according to claim 1, wherein: Determining the bit error rate according to the signal-to-noise ratio and the state of the flight ad hoc network includes: When the state of the flight ad hoc network is offline, generating a lookup table of bit error rate and frame error rate; When the state of the flight self-organizing network is online, the lookup table is dynamically called according to the topology structure and the navigation deviation to obtain the link quality state.

7. The link evaluation method according to claim 1, wherein: The link loss includes path loss, atmospheric attenuation loss and polarization loss.

8. The link evaluation method according to claim 1, wherein: The node parameters include: node antenna type, beam pointing parameters, transmit power, modulation mode, receiving sensitivity and noise figure.

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