Implementation Of The Fast-changing DS/FH System Based On The MicroTCA Platform

As an important part of the information warfare,the electronic warfare uses electronic detection methods and electronic attrack methods to control the information in the war,so enhancing electronic defense measures to ensure the anti-i nterference and anti-jammi ng of military communications is the only way of military communication.FR stealth,as electronic defence measure,is the first line of defense and can control the power of the signal to reduce the possibility of signal detection.The traditional spread spectrum technolody can reduce the signal power spectral density to make the signal hidden in the noise,so it is widely used in the military communication.However,with the methods of interference and detection various,the mainly parameters of the spread spectrum technology using fi xed parameters can be estimated by high order cumulant method and other methods,which is a threat to the concealment of the signal.Therefore,this thesis mainly studies the direct sequence/frequency hopping(DS/FH)communication system whose parameters are rapidly changing and its engineering methods.Compared with the tranditional DS/FH communication system,the fast-changing DS/FH communication system can make the parameters of the chip,the parameters in time domain and i n the frequency domai n fast changi ng,through variable speed pattern,which can weaken the correlation of different time observed signal and enhance the performance of the anti-interception.So it is difficult to detect the signal for the reconnaissance side even if usi ng the high order cumulants and other methods.However,the receiver need long time and a large number of computation to complete the synchronization,which increases the difficulty of signal synchroni zation,so greater demands are being placed on the synchroni zation algorithms and the performance of the implementation.The main research contents and work are as follows:Firstly,this thesis gi ves the fast-changing DS/FH communication pri nciple,the signal design method and the system structure.B y matlab,usi ng the methods of parameter estimation to analysis the performance of anti-interception,the results show that the performance of anti-interception of the fast-changing DS/FH communication system is stronger than the tranditional DS/FH communication system.In order to reali ze the acquisition of the fast-changing DS/FH signal,in this thesis,a frequency-domai n matched filter acquisition based on position threshold is proposed.This algorithm uses the position thres hold instead of the traditional noise threshold,and avoids the i nfluence of the estimation error of the noise threshold on the synchronization performance and reduces the overhead of the noise estimation.Meanwhile,this method can improve the capture probability by usi ng the shift pattern to merge the multiple signals.Secondly,i n order to test the fast-changing DS/FH communication system,the fast-changing DS/FH communication experimental system is constructed,which is consist of the experimental prototype machine and the software termi nal.Based on the software radio platform of the MicroTCA architecture,the fast-changing communication system experimental prototype machine is achieved and mai nly completes the baseband signal processing part.The software terminal not only supports the configuration of the system parameters and various transmission services,but also implements the continuous test module and burst test module,which are convenient for the system test.Finally,under the condition of i ndoor and outdoor,the performance of the fast-changing DS/FH communication system has been tested and the test results meet the requirements of the project.