The Helicopter Satellite Communication Research And Implementation Of Key Technologies

Owing to the significant features of themselves,helicopters are extremely important in aspects of civil and military use,especially in emergency treatment for natural disasters and military detection.Furthermore,helicopters are particularly more important in transportation and support.Under these circumstances,the ground communication network may lose efficacy because of natural disasters or the enemy's destruction,missions of helicopters couldn't be accomplished,which immensely restricts the use of helicopters.Hence,the helicopter satellite communications with high-speed stability guarantees the normal communication and use of helicopters,which could reduce economic loss,save lives,reverse situations,etc.Therefore,it's quite important to research the satellite communication of helicopters.The primary research objects on the satellite communication of helicopters include fading channel model,anti helicopter rotor block communication and helicopter satellite communication solutions.In this thesis,firstly the features of the helicopter satellite communication channel are analysed,then the fading channel model is proposed based on some mature channel models,finally the typical value distribution of the channel is simulated in MATLAB.Aiming at helicopter rotor block,the methods such as convolutional encoding,interleaved encoding,Hadamard matrix transformation,double time diversity,space diversity and polarity diversity used to improve the performance in anti rotor blockage are simulated and analysed,meanwhile the technical performance between average power sliding window method and occlusions detection in feedback sliding window decision are compared.Then an optimal anti-overlap communication combination method is achieved by combing these methods above organically and simulating the effect when using these combination methods in occlusions system.At last,aiming at band communication,firstly the communication scheme is designed by combing transmission condition and anti-block communication method,which solves the Doppler frequency shift,helicopter rotor block and noise problem in transmission.Then some key technologies including the design of frame format,carrier synchronization,compensation of residual frequency offset are analysed in principle and simulated,finally the system module of the communication scheme is implemented on the Xilinx's FPGA chip “XC7K325T”,the implementation principles and results of the key modules like carrier synchronization and residual frequency offset compensation are verified,the resource consumption of hardware implementation is also evaluated.