Research On GBSM Air-to-air Channel Modeling Method Based On 3D Terrain Map

Air-to-air communication is one of the common and important scenarios in communication electronic warfare,and performance simulation of air-to-air communication system in the context of complex terrain is becoming more urgently needed,while air-to-air wireless channel is the decisive factor for communication performance in such scenarios.Therefore,the study of air-to-air channel characteristics and modeling methods can provide assistance and support for the pre-verification of communication system design on the one hand,and support the verification of communication performance of existing communication systems in complex electromagnetic environments on one hand,so as to assist in the optimization of communication system parameters and the evaluation and strategy generation of anti-jamming performance in adversarial scenarios.Air-to-air communication scenarios are generally characterized by long distance,high dynamics,wide span,and complex propagation environments,so actual measurement of air-toair wireless channels is costly,difficult to implement,and there is fewer publicly available data sets.In addition,using the existing Geometry-based Stochastic Channel Model(GBSM)to model the air-air channel lacks relevance to the actual communication terrain simulation.There is a certain gap in the modeling method using the three-dimensional terrain of the communication scene.To meet the communication needs of long-distance air-to-air communication in the context of complex terrain,this paper uses the GBSM method based on3 D terrain map to establish the air-to-air channel model,and carries out the rapid identification of the channel model according to the communication scene,and makes a preliminary exploration of the real-time channel modeling based on 3D terrain.The main contributions of this paper are as follows:(1)A GBSM channel model based on 3D terrain map for long-distance air-to-air communication scenarios is established.Firstly,the digital elevation model(DEM)of the studied communication scenario is processed using a grid-based modeling approach;secondly,the terrain locations in the DEM that affect the signal free-space Line of Sight(Lo S)propagation are determined using the properties of the 3D Fresnel zone;then,the GBSM modeling method is used to obtain the single-sphere model,its Channel Impulse Response(CIR)and channel characteristics.The channel characteristics include Space-Time Correlation Function(STCF),Level Crossing Rate(LCR),and Average Fade Duration(AFD);finally,the electromagnetic characteristics parameters of the RT are solidified based on the available measured data to ensure the applicability of the ray tracing method in such communication scenarios,and then the channel characteristics are obtained by the RT and compared with the corresponding characteristics of the proposed model to verify the correctness of the proposed model.(2)A YOLOv5-based method for fast identification of channel models is proposed.Since communication scenes with wide span and long distance usually have rich terrain details,the processing of terrain data is relatively time-consuming for each modeling.This method solves this problem by using YOLOv5 recognition to quickly identify the channel model of a predefined scene.Firstly,the normalized DEM and transceiver elevation data are represented by color coding method;secondly,all other classes of current data belonging to single-sphere model or non-single-sphere model are determined by the method in Chapter 3and used as labels to make training data sets;finally,recognition tests are conducted and the results show that the mean Average Precision(m AP)of this method can reach 99.3% and the average recognition speed is 45.3ms,which can satisfy the real-time channel modeling of the pre-defined environment to some extent.