Urban low-altitude scene-oriented unmanned aerial vehicle air-to-air channel modeling simulation method

Abstract

The invention discloses an unmanned aerial vehicle air-to-air channel modeling simulation method for an urban low-altitude scene, and the method comprises the steps: calculating the time delay, total phase and power of a sight distance path of an unmanned aerial vehicle transmitting and receiving end in a channel model according to the input position parameters of the transmitting and receiving end; calculating to obtain a channel impulse response of the sight distance path by combining a sight distance path antenna pattern function related to the attitude; calculating the time delay, the total phase and the power of a roof reflection path in the channel model in combination with communication scene parameters; in combination with a non-line-of-sight path antenna pattern function related to the attitude, calculating to obtain a channel impulse response of a roof reflection path; calculating the time delay, the total phase and the power of a non-line-of-sight path in the channel model in combination with geometrical relationship parameters limiting scatterer distribution; calculating to obtain a channel impulse response of a non-line-of-sight path in combination with an antenna pattern function related to the attitude; and establishing an unmanned aerial vehicle air-to-air channel model, and outputting a channel coefficient. According to the invention, efficient and accurate reproduction of the air-to-air channel of the unmanned aerial vehicle is realized.

Description

Technical Field

[0001] The present invention relates to the field of wireless information transmission, and particularly to a method for modeling and simulating an unmanned aerial vehicle (UAV) - to - UAV channel for urban low - altitude scenarios. Background Art

[0002] With the development of 5G / 6G and the Internet of Things, low - altitude digital infrastructure has become the key to intelligent development. Combining technological breakthroughs such as artificial intelligence and edge computing, the application of UAVs is accelerating, especially the increasing communication requirements in low - altitude environments. In the low - altitude urban market scenario, UAVs can not only undertake tasks such as urban monitoring and logistics distribution, but also play an important role in emergency communication and disaster relief. The complexity of the low - altitude urban market scenario makes the communication between UAVs face significant challenges. In particular, factors such as dense buildings and signal multipath propagation have a great impact on signal transmission. Therefore, accurate modeling of the UAV - to - UAV channel in low - altitude scenarios has become the key to improving UAV communication performance.

[0003] Currently, traditional channel models, such as those for ground or air - to - ground, have been widely studied. However, due to its unique challenges, the air - to - air channel urgently needs new modeling methods. Different from ground or air - to - ground scenarios, in the low - altitude urban environment, both the transmitter and receiver of air - to - air communication are in the air, which changes the signal propagation characteristics and the distribution of scatterers in the environment. In addition, most of the air - to - ground channel models for UAVs regard UAVs as point masses, ignoring the impact of the fuselage structure and attitude changes on the channel. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for modeling and simulating an unmanned aerial vehicle (UAV) - to - UAV channel for urban low - altitude scenarios, which can comprehensively consider factors such as the attitude and position changes of UAVs and the actual distribution characteristics of scatterers, effectively improving the authenticity and accuracy of the channel model, thereby enhancing the communication quality of UAVs.

[0005] To achieve the above - mentioned technical purpose, the technical solution adopted by the present invention is as follows: A method for modeling and simulating an unmanned aerial vehicle (UAV) - to - UAV channel for urban low - altitude scenarios, the method comprising the following steps: S1, according to the input position parameters of the transmitter and receiver, calculate the delay, total phase, and power of the line - of - sight (LOS) path of the UAV transmitter and receiver in the channel model; combine the LOS path antenna pattern function related to the attitude to calculate the channel impulse response of the LOS path; S2, combine the communication scenario parameters to calculate the delay, total phase, and power of the roof reflection path in the channel model; combine the non - LOS path antenna pattern function related to the attitude to calculate the channel impulse response of the roof reflection path; S3. Combine the height and horizontal geometric relationship parameters that limit the scatterer distribution to calculate the delay, total phase, and power of the non-line-of-sight path in the channel model; combine the non-line-of-sight path antenna pattern function related to the attitude to calculate the channel impulse response of the non-line-of-sight path. S4. Establish a UAV-to-UAV channel model, substitute the calculation results of steps S1 to S3, and output the channel coefficients. The UAV-to-UAV channel model is as follows: ; In the formula, represents the channel impulse response between the th transmit antenna and the th receive antenna, t represents time, represents the delay, represents the time-varying Rice factor, and represent the power coefficients of the rooftop reflection path and the non-line-of-sight path, satisfying ; , and represent the channel impulse responses of the line-of-sight path, rooftop reflection path, and non-line-of-sight path.

[0006] Compared with the prior art, the beneficial effects of the present invention are as follows: First, the UAV-to-UAV channel modeling and simulation method for urban low-altitude scenarios of the present invention combines factors such as the real scattering environment and the UAV fuselage structure. In the case of three-dimensional movement, fuselage rotation, and occlusion at both the UAV-to-UAV communication transceiver ends, the generation and calculation methods of channel parameters are given at the simulation level, realizing the efficient and accurate reproduction of the UAV-to-UAV channel.

[0007] Second, the UAV-to-UAV channel modeling and simulation method for urban low-altitude scenarios of the present invention introduces a rooftop reflection mechanism and corrects the power in combination with the UAV fuselage occlusion effect. Compared with the traditional standardized model, the present invention can more accurately characterize the non-line-of-sight propagation path in the low-altitude urban environment, making up for the limitations of the current model and improving the accuracy of channel modeling.

[0008] Third, the UAV-to-UAV channel modeling and simulation method for urban low-altitude scenarios of the present invention uses the terrain statistics method to calculate the parameters related to the rooftop reflection path, gives the calculation methods related to the non-line-of-sight path parameters, and improves the inaccuracy of the traditional method in calculating the line-of-sight path power in the case of fuselage occlusion. The present invention can realize the efficient and accurate simulation and reproduction of the UAV-to-UAV channel in the urban scenario. Description of the Drawings

[0009] Figure 1 is the flow chart of the UAV-to-UAV channel modeling and simulation method for urban low-altitude scenarios of the present invention; Figure 2 Schematic diagram of the scenario of UAV-to-UAV communication in the present invention; Figure 3 Power delay profile of the rooftop reflection path and the non-line-of-sight path in the present invention; Figure 4 Schematic diagram of the channel coefficients generated in the first 3 seconds of the present invention; Figure 5 Schematic diagram of the user-defined parameters input in the example; Figure 6 Schematic diagram of the UAV motion parameters in the example. Detailed implementation manners

[0010] The following further describes the embodiments of the present invention in detail with reference to the accompanying drawings.

[0011] The present invention discloses a method for UAV-to-UAV channel modeling and simulation for low-altitude urban scenarios, including the following steps: 1) Input user configuration parameters. Specifically, it includes: communication scenario type, carrier frequency, antenna type, initial position vectors and velocity vectors of the UAV transceiver, and parameters such as the motion trajectories of the transceiver. 2) Calculate the delay, total phase and power of the line-of-sight path between the UAV transceiver in the channel model according to the positions of the transceiver. 3) Calculate the delay, total phase and power of the rooftop reflection path in the channel model in combination with the communication scenario. 4) Calculate the delay, total phase and power of the non-line-of-sight path in the channel model in combination with the geometric relationship. 5) Establish a UAV-to-UAV channel model, substitute the parameters calculated in steps 1) to 4), and output the channel coefficients.

[0012] Step 2) specifically includes: 21) Calculate the position vectors of the antennas at the transceiver, and the method is as follows: Calculate the positions of the UAV transceiver at time : ; where and respectively represent the velocity vectors of the UAV transmitter and receiver, and the calculation method is: ; wherein, represents the modulo operation, represents the azimuth angle of the motion speeds of the transmitter and receiver, represents the elevation angle of the motion speeds of the transmitter and receiver.

[0013] Furthermore, the position vectors of the antennas at the transceiver Can be expressed as: ; Wherein, and respectively represent the vectors pointing from the transceiver center to the transmitting end and the th and the th antenna element units of the receiving end.

[0014] 22) According to the position vectors of the transmitting and receiving antennas calculated in step 21), calculate the delay of the line-of-sight path : ; Where represents the line-of-sight path length, is the propagation speed of electromagnetic waves.

[0015] 23) Calculate the total phase of the line-of-sight path, the steps are as follows: 231) According to the line-of-sight path length calculated in step 22), calculate the initial phase of the line-of-sight path : ; Wherein, represents the wave number, represents the carrier frequency, and the unit is MHz.

[0016] 232) Calculate the Doppler phase of the line-of-sight path : ; In the formula, represents the angular unit vector of the line-of-sight path at the transmitting end, which can be obtained by converting the azimuth angle and elevation angle of the line-of-sight path into the Cartesian coordinate system. The azimuth angle of the transmitting end, the azimuth angle of the receiving end, the elevation angle of the transmitting end, and the elevation angle of the receiving end are calculated as follows: ; ; ; ; 233) Calculate the antenna calibration phase of the line-of-sight path : ; Where represents the attitude matrix of the UAV transmitting end or receiving end, which is provided in real time by the inertial measurement unit carried by the UAV and can be modeled as: ; , and respectively represent the roll angle, pitch angle, and yaw angle in the attitude angle.

[0017] 234) Calculate the total phase of the LOS path according to the initial phase, Doppler phase, and antenna correction phase of the LOS path in steps 231), 232), and 233). : ; 24) Calculate the power of the LOS path as follows: 241) Define the set of fuselage structure parameters : ; Among them, represents the leading-edge sweep angle, represents the trailing-edge sweep angle, represents the dihedral angle, represents the fuselage width, represents the wingspan, represents the fuselage length, represents the vertical distance from the antenna to the x - y plane, represents the wing chord length.

[0018] 242) Calculate the position vector of the fuselage diffraction point : ; Among them represents the th diffraction path; represents the vector from the th transmitting or the th receiving antenna element to the edge of the fuselage, which is determined by the set of fuselage structure parameters and the coordinate system.

[0019] 243) To describe the attenuation degree of the signal, define the dimensionless parameter : ; Among them represents the vertical distance from the diffraction point on the fuselage to the straight line connecting the transmitting end and the receiving end, represents the angle (in radians) formed by the transmitting end, diffraction point, and receiving end, and the calculation methods are respectively: ; ; 244) Calculate the power factor of the LOS path considering the body shadowing effect : ; where and represent the thresholds determined according to the diffraction attenuation degree, is a correction constant.

[0020] Step 3) specifically includes: 31) Calculate the time delay of the rooftop reflection path, the steps are as follows: 311) Calculate the path length of the rooftop reflection path : ; where represents the coordinates of the rooftop reflection point. A coordinate system is established with the projection of the line connecting the transmitter and the receiver on the horizontal plane as the x-axis, and the y-axis component is determined to be 0. The remaining components are calculated using the property of similar triangles, and the method is as follows: ; ; where represents the height of the rooftop reflection point from the ground, and its probability density function is: ; where represents the proportion of land covered by buildings, represents the average building height.

[0021] 312) Calculate the time delay according to the path length of the rooftop reflection path : ; 32) Calculate the total phase of the rooftop reflection path, the method is as follows: 321) Calculate the initial phase of the rooftop reflection path : ; 322) Calculate the Doppler phase of the rooftop reflection path : ; Unit direction vector and can be obtained by converting the azimuth and elevation angles of the rooftop reflection path into Cartesian coordinates. The calculation methods of the azimuth angle and the elevation angle are as follows: ; ; 323) Calculate the antenna correction phase of the roof reflection path : ; 324) Calculate the total phase of the roof reflection path according to the initial phase, Doppler phase, and antenna correction phase in steps 321), 322), and 323) : ; 33) Calculate the power factor of the roof reflection path : ; where represents the complex reflection coefficient, and the calculation method is: ; where is the polarization correlation coefficient and follows , represents the relative dielectric constant of the reflection material.

[0022] Step 4) specifically includes: 41) Calculate the time delay of the non-line-of-sight path as follows: 411) Calculate the path length of the m-th sub-path of the n-th non-line-of-sight path : ; where represents the coordinate vector of the scattering point, which can be denoted as , and the calculation method is: ; where R represents the horizontal distance parameter restricting the scatterer distribution, and H represents the vertical distance parameter restricting the scatterer distribution.

[0023] 412) Calculate the time delay of the m-th sub-path of the n-th non-line-of-sight path : ; 42) Calculate the total phase of the m-th sub-path in the n-th non-line-of-sight path as follows: 421) Calculate the initial phase of the m-th sub-path in the n-th non-line-of-sight path : ; 422) Calculate the Doppler phase of the m-th sub-path in the n-th non-line-of-sight path : ; wherein represents the angular unit vector of the m-th sub-path in the n-th non-line-of-sight path at the transmitting or receiving end, which can be obtained by converting the azimuth angle and elevation angle into the Cartesian coordinate system. The azimuth angle and elevation angle are calculated as follows: ; ; 423) Calculate the antenna calibration phase of the m-th sub-path in the n-th non-line-of-sight path : ; 424) Calculate the total phase of the m-th sub-path in the n-th non-line-of-sight path according to the initial phase, Doppler phase and antenna calibration phase in steps 421), 422) and 423) : ; 43) Calculate the original power factor of the non-line-of-sight path : ; wherein represents the delay scalar, represents the delay spread, represents the cluster shadow fading following the Gaussian distribution. Calculate the power factor of the non-line-of-sight path : .

[0024] Step 5) specifically includes: Construct the low-altitude scenario UAV-to-UAV channel model as follows: ; In the formula, represents the channel impulse response between the -th transmitting antenna and the -th receiving antenna. t represents time, represents the delay, represents the time-varying Rice factor, and represent the power coefficients of the roof reflection path and other non-line-of-sight paths, satisfying . , and represent the channel impulse responses of the line-of-sight path, roof reflection path and other non-line-of-sight paths respectively, and the specific expressions are as follows: ; ; ; Among them, represents the number of non-line-of-sight paths, represents the number of sub-paths. , and represent power factors, , and represent the phase components of the propagation path, , and represent the corresponding time delays, and represent the antenna pattern function related to the attitude, and the calculation method is: ; ; Wherein and represent the antenna pattern components of the transmitting or receiving end in the vertical and horizontal planes. , , and represent the initial phases of different polarization combinations, which are used to describe the polarization phase changes of the line-of-sight and non-line-of-sight paths. represents the cross-polarization power ratio. represents the attitude matrix of the UAV transmitting or receiving end.

[0025] Example Reference Figure 1 and Figure 2 As shown, in one example of the UAV-to-UAV channel modeling and simulation method for urban low-altitude scenarios of the present invention, it is specifically as follows: 1) Input user-defined parameters, specifically: communication scenario type, initial position vectors of UAV transceiver, speed, three-dimensional motion trajectory, azimuth and pitch angles of the motion direction, carrier frequency, antenna type, roof material, simulation time, channel state update interval, etc.; for specific parameters, see Figure 5 and Figure 6 .

[0026] 2) Calculate the time delay, total phase, and power of the line-of-sight path, and the steps are as follows: 21) Calculate the position vectors of the transceiver antennas, and the method is as follows: According to the input UAV initial position and speed information, calculate the position of the UAV transceiver at time : ; Wherein and are the velocity vectors of the UAV transmitting end and receiving end respectively, and can be expressed as: ; where represents the modulo operation, and represent the azimuth angle and elevation angle of the movement speed respectively. For example, the velocity vector at the initial moment can be expressed as: , ; Furthermore, the position vector of the transceiver antennas can be calculated as: ; where represents the vector pointing from the center position of the transmitting end to the th antenna element unit, represents the vector pointing from the center of the receiving end to the th antenna element unit.

[0027] 22) According to the position vectors of the transceiver antennas calculated in step 21), calculate the delay of the line-of-sight path: ; where represents the length of the line-of-sight path, represents the propagation speed of electromagnetic waves, and the value is .

[0028] 23) Calculate the total phase of the line-of-sight path, the steps are as follows: 231) According to the length of the line-of-sight path obtained in step 22), calculate the initial phase of the line-of-sight path: ; 232) Calculate the Doppler phase of the line-of-sight path: ; The unit direction vector can be obtained by converting the azimuth angle and elevation angle of the line-of-sight path into Cartesian coordinates.

[0029] 233) Calculate the antenna calibration phase of the line-of-sight path: ; For example, when the simulation is 2.5 s, the attitude matrices of the transmitting and receiving ends can be calculated as: , ; 234) Calculate the total phase of the LOS path based on the initial phase, Doppler phase, and antenna calibration phase of the LOS path in steps 231), 232), and 233). : ; 24) Calculate the power of the LOS path as follows: 241) Define the set of fuselage structure parameters : ; where represents the leading edge sweep angle, represents the trailing edge sweep angle, represents the dihedral angle, represents the fuselage width, represents the wingspan, represents the fuselage length, represents the vertical distance of the antenna from the x - y plane, represents the wing chord length. The value is .

[0030] 242) Determine the position vector of the fuselage diffraction point through the set of fuselage structure parameters and the position vector of the UAV antenna in step 21) : ; where represents the th diffraction path, represents the vector from the transmitting or receiving antenna element to the edge of the fuselage.

[0031] 243) Define the dimensionless parameter to quantify the attenuation degree of the signal: ; where represents the perpendicular distance from the diffraction point of the fuselage to the straight line connecting the transmitting end and the receiving end, represents the angle (in radians) formed by the transmitting end, the diffraction point, and the receiving end. The calculation methods are respectively: ; ; 244) Calculate the power factor of the LOS path considering the fuselage shielding effect : .

[0032] Step 3) specifically includes: 31) Calculate the delay of the roof reflection path as follows: 311) Calculate the path length of the rooftop reflection path : ; where represents the coordinates of the rooftop reflection point. A coordinate system is established with the projection of the line connecting the transmitter and the receiver on the horizontal plane as the x-axis, determining that the y-axis component is 0, and the remaining components are calculated using the property of similar triangles. The method is as follows: ; ; where represents the height of the rooftop reflection point from the ground and is generated using a statistical method , and its probability density function is: ; 312) Calculate the time delay based on the path length of the rooftop reflection path calculated in step 311) : ; 32) Calculate the total phase of the rooftop reflection path. The method is as follows: 321) Calculate the initial phase of the rooftop reflection path based on the path length obtained in step 311) : ; 322) Calculate the Doppler phase of the rooftop reflection path : ; 323) Calculate the antenna calibration phase in the rooftop reflection path : ; 324) Calculate the total phase of the rooftop reflection path based on the initial phase, Doppler phase, and antenna calibration phase in steps 321), 322), and 323) : ; 33) Calculate the power factor of the rooftop reflection path : .

[0033] Step 4) Specifically includes: 41) Calculate the time delay of the m-th sub-path of the n-th non-line-of-sight path. The method is as follows: 411) Calculate the path length of the m-th sub-path in the n-th non-line-of-sight path : ; Among them represents the coordinate vector of the scattering point and can be denoted as , and the calculation method is as follows: ; 412) Calculate the time delay of the m-th sub-path in the n-th non-line-of-sight path: ; 42) Calculate the total phase of the m-th sub-path in the n-th non-line-of-sight path. The method is as follows: 421) Calculate the initial phase of the m-th sub-path in the n-th non-line-of-sight path according to the path length obtained in step 411) : ; 422) Calculate the Doppler phase of the m-th sub-path in the n-th non-line-of-sight path : ; 423) Calculate the antenna calibration phase of the m-th sub-path in the n-th non-line-of-sight path : ; 424) Calculate the total phase of the m-th sub-path in the n-th non-line-of-sight path according to the initial phase, Doppler phase and antenna calibration phase of the sub-path in steps 421), 422) and 423) : ; 43) Calculate the original power factor of the non-line-of-sight path : ; Among them, represents the time delay scalar, represents the time delay spread, represents the cluster shadow fading following the Gaussian distribution. Calculate the power factor of the non-line-of-sight path : .

[0034] In this example, the time delay and power of the roof reflection path and the non-line-of-sight path calculated are specifically as Figure 3 shown

[0035] Step 5) specifically includes: The constructed low-altitude scenario UAV-to-UAV channel model is as follows: ; In the formula, represents the Channel impulse response between the root transmit antenna and the th root receive antenna, where \(t\) represents time, represents the time delay, represents the time-varying Rice factor, and represent the power coefficients of the rooftop reflection path and other non-line-of-sight paths, satisfying . , and represent the channel impulse responses of the line-of-sight path, rooftop reflection path and other non-line-of-sight paths, and the specific expressions are as follows: ; ; ; wherein, represents the number of non-line-of-sight paths, represents the number of sub-paths. Omnidirectional antennas are used, and \(\varphi\) represents the antenna pattern function related to the attitude and take the value of 1, substitute the parameters such as time delay, phase, and power factor calculated in steps 1) to 4) into the UAV-to-UAV channel model in the low-altitude scenario, and output the channel coefficients. The specific channel coefficients obtained in this example are as Figure 4 shown.

[0036] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed to include the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0037] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these changes and modifications.

Claims

1. A UAV air-to-air channel modeling and simulation method for urban low-altitude scenes, characterized in that: The method comprises the following steps: S1, based on the input transceiver position parameters, calculate the delay, total phase and power of the UAV transceiver line-of-sight path in the channel model; combined with the attitude-related line-of-sight path antenna pattern function, calculate the channel impulse response of the line-of-sight path; S2, combined with the communication scenario parameters, calculates the delay, total phase and power of the roof reflection path in the channel model; combined with the attitude-related non-line-of-sight path antenna pattern function, calculates the channel impulse response of the roof reflection path; S3, combining the height and horizontal geometric relationship parameters of the restricted scatterer distribution, calculates the delay, total phase and power of the non-line-of-sight path in the channel model; combining the non-line-of-sight path antenna pattern function related to the attitude, calculates the channel impulse response of the non-line-of-sight path; S4, establish a drone air-to-air channel model, substitute the calculation results of steps S1 to S3, and output the channel coefficient; the drone air-to-air channel model is: ； In the formula, Indicates The transmitting antenna and The channel impulse response between the root receiving antennas, t represents time, Indicates delay, represents the time-varying Rice factor, and Represents the power coefficient of the roof reflection path and the non-line-of-sight path, satisfying ; , and Represents the channel impulse response for line-of-sight paths, rooftop reflection paths, and non-line-of-sight paths.

2. The UAV air-to-air channel modeling and simulation method for urban low-altitude scenes according to claim 1 is characterized in that: In step S1, the process of calculating the delay, total phase and power of the line-of-sight path of the UAV transceiver in the channel model includes the following steps: S11, calculation The location of the drone's transmitter and receiver at all times : ； in and Respectively The velocity vector of the transmitting and receiving ends of the drone at time and They represent the transmitting end and the receiving end respectively; The position vector of the transmitting and receiving antennas It is expressed as: ； in, Indicates that the center of the transmitter points to The vector of root antenna element units, Indicates that the receiving end center points to Vector of root antenna element units; S12, calculating the time delay of the line-of-sight path according to the position vector of the transmitting and receiving antennas calculated in step S11 : ； in represents the line-of-sight path length, is the propagation speed of electromagnetic waves; S13, calculate the initial phase of the line-of-sight path : ； in, represents the wave number, Indicates the carrier frequency; Calculate the Doppler phase for a line-of-sight path : ； in, The angular unit vector representing the line-of-sight path of the transmitter; Calculate antenna correction phase for line-of-sight paths : ； in Represents the attitude matrix of the UAV transmitter or receiver, The angular unit vector representing the receiving end's line-of-sight path; Calculate the total phase for a line-of-sight path : ； S14, define the fuselage structure parameter set : ； in, represents the leading edge sweep angle, represents the trailing edge sweep angle, represents the dihedral angle, Indicates the width of the fuselage. represents the wing span, Indicates the fuselage length, represents the vertical distance between the antenna and the xy plane, represents the chord length of the wing; Calculate the position vector of the diffraction point of the body : ； in Indicates diffraction paths, Indicates Root emission or The vector from the root receiving antenna element to the edge of the fuselage; Defining dimensionless parameters : ； in It represents the vertical distance from the diffraction point on the fuselage to the straight line connecting the transmitter and the receiver. Represents the angle formed by the transmitting end, the diffraction point and the receiving end; Calculate the power factor of the line-of-sight path considering the shadowing effect of the fuselage : ； in Indicates the threshold for distinguishing between unobstructed and partially obstructed airframe based on the degree of diffraction attenuation. It represents the threshold for distinguishing partial occlusion from complete occlusion based on the degree of diffraction attenuation. is the correction constant.

3. The UAV air-to-air channel modeling and simulation method for urban low-altitude scenes according to claim 1 is characterized in that: In step S1, the channel impulse response of the line-of-sight path is: ； In the formula, represents the Dirac function, represents the power factor for the line-of-sight path, represents the total phase of the line-of-sight path, represents the delay of the line-of-sight path, The attitude-dependent line-of-sight path antenna pattern function: ； in represents the antenna pattern component of the transmitter in the vertical plane, represents the antenna pattern component of the receiving end in the vertical plane, represents the antenna pattern component of the transmitter in the horizontal plane, Represents the antenna pattern component of the receiving end in the horizontal plane; Indicates vertical transmission and vertical reception polarization mode. Indicates the horizontal transmission and horizontal reception polarization modes, both used to describe the polarization phase change of the line of sight; Represents the attitude matrix of the UAV transmitter or receiver.

4. The method for modeling and simulating air-to-air channels of unmanned aerial vehicles for urban low-altitude scenes according to claim 1 is characterized in that: In step S2, the process of calculating the delay, total phase and power of the rooftop reflection path in the channel model in combination with the communication scenario parameters includes the following steps: S21, calculate the path length of the roof reflection path : ； in Represents the coordinate components of the position vector of the receiving antenna, Represents the coordinate components of the position vector of the transmitting antenna, represents the coordinates of the roof reflection point, Represents the coordinate components of the roof reflection point. The projection of the line between the transmitter and the receiver on the horizontal plane is used as the x-axis to establish a coordinate system. The y-axis component is determined to be 0. The remaining components are calculated using the triangle similarity property as follows: ； ； in, represents the unit vector of the x-axis, represents the unit vector of the z-axis, Represents the height of the roof reflection point from the ground, and its probability density function is: ； in represents the proportion of land covered by buildings, represents the average building height; Calculate the delay based on the path length of the roof reflection path : ； In the formula, is the propagation speed of electromagnetic waves; represents the path length of the roof reflection path; S22, calculate the initial phase of the roof reflection path : ； in, represents the wave number, Indicates the carrier frequency; Calculate the Doppler phase of the roof reflection path : ； in, Represents the unit direction vector of the reflection path of the roof of the transmitter, Represents the unit direction vector of the reflection path of the receiving end roof, and Respectively The velocity vectors of the transmitting and receiving ends of the drone at the moment; Calculate antenna correction phase for rooftop reflection path : ； in, Respectively The location of the drone transmitter or receiver at the moment, Represents the attitude matrix of the UAV transmitter or receiver; Calculate the total phase of the roof reflection path : ； S23, calculate the power factor of the roof reflection path : ； in represents the complex reflection coefficient.

5. The UAV air-to-air channel modeling and simulation method for urban low-altitude scenes according to claim 1 is characterized in that: In step S2, the channel impulse response of the roof reflection path is: ； in, Indicates the number of non-line-of-sight paths; Represents the power factor of the roof reflection path, represents the total phase of the roof reflection path, represents the time delay of the roof reflection path, represents the attitude-dependent non-line-of-sight path antenna pattern function; ； in represents the antenna pattern component of the transmitter in the vertical plane, represents the antenna pattern component of the receiving end in the vertical plane, represents the antenna pattern component of the transmitter in the horizontal plane, Represents the antenna pattern component of the receiving end in the horizontal plane; Indicates the initial phase of vertical transmission and vertical reception polarization in non-line-of-sight path. Indicates the initial phase of horizontal transmission and horizontal reception polarization in non-line-of-sight path. Indicates the initial phase of the vertical transmission and horizontal reception polarization of the non-line-of-sight path, Indicates the initial phase of horizontal transmission and vertical reception polarization in non-line-of-sight path; represents the cross-polarization power ratio; Represents the attitude matrix of the UAV transmitter or receiver.

6. The method for modeling and simulating air-to-air channels of unmanned aerial vehicles for urban low-altitude scenes according to claim 1 is characterized in that: In step S3, the process of calculating the delay, total phase and power of the non-line-of-sight path in the channel model in combination with the geometric relationship parameters of the restricted scatterer distribution includes the following steps: S31, calculating the path length of the mth sub-path of the nth non-line-of-sight path : ； in Represents the coordinate vector of the scattering point, denoted as , the calculation method is: ； Among them, R represents the horizontal distance parameter that limits the distribution of scatterers, and H represents the vertical distance parameter that limits the distribution of scatterers. express The location of the transmitting or receiving end of the drone at the moment; Calculate the delay of the mth subpath of the nth non-line-of-sight path : ； S32, calculate the initial phase of the mth sub-path in the nth non-line-of-sight path : ； in, represents the wave number, Indicates the carrier frequency; Calculate the Doppler phase of the mth subpath in the nth non-line-of-sight path : ； in Represents the angular unit vector of the mth subpath in the nth non-line-of-sight path at the transmitter or receiver, and Respectively The velocity vectors of the transmitting and receiving ends of the drone at the moment; Calculate the antenna correction phase for the mth subpath in the nth non-line-of-sight path : ； In the formula, Represents the attitude matrix of the UAV transmitter or receiver; Calculate the total phase of the mth subpath in the nth non-line-of-sight path : ； S33, calculate the raw power factor of the non-line-of-sight path : ； in, represents the delay scalar, represents the delay spread, Represents cluster shadow fading following a Gaussian distribution and calculates the power factor of the non-line-of-sight path : ； In the formula, represents the number of non-line-of-sight paths, Indicates the number of subpaths.

7. The method for modeling and simulating air-to-air channels of unmanned aerial vehicles for urban low-altitude scenes according to claim 1 is characterized in that: In step S3, the channel impulse response of the non-line-of-sight path is: ； in, represents the number of non-line-of-sight paths, Indicates the number of subpaths; represents the power factor of the non-line-of-sight path, represents the phase component of the non-line-of-sight path, represents the delay of the non-line-of-sight path, Represents the antenna pattern function related to attitude.

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