| Satellite communication is one of today's mainstream communication technologies.It is a typical wireless communication method.It is widely used in all aspects of people's lives,such as map navigation,climate monitoring,remote sensing technology,satellite broadcasting and television,satellite phones,and so on.At the same time,satellite communication is also an indispensable means of communication technology in modern warfare,such as transmitting various commands,control,and reconnaissance information,positioning enemy weapons and equipment,and so on.Satellite communication is so important,but it is often interfered by various factors,mainly natural environment and manmade interference,especially when satellite communication is used in the military field,the factor of man-made interference is more prominent.In order to ensure the high reliability of information transmission,communication anti-jamming technology is slowly being developed.With the changes in demand for information operations and the in-depth development of electronic countermeasures and games,communication anti-jamming technology has become the frontier research field of today's high-tech weapons and equipment.In order to meet the requirements of information warfare and the development of information weapons,communication anti-jamming is no longer limited to point-to-point communication,and even needs to be developed into anti-jamming networks.At the same time,it has also developed to multi-dimensional joint anti-jamming technology,including time domain,frequency domain,space domain,information domain,etc.,and joint antijamming from the multi-dimensional domain can also achieve better anti-jamming effects.This article studies its anti-jamming technology for satellite communications,and the main work is as follows:(1)From the perspective of multi-dimensional domains such as time domain,frequency domain,and information domain,the anti-jamming technology is studied;in the time domain,the anti-jamming ability of different diversity combining times and different diversity combining methods is studied;in the frequency domain,direct spreading is studied.Frequency and frequency hopping gain the anti-jamming performance of the system;in the information domain,taking the LDPC coding method as the research object,the improvement of the anti-jamming performance of the system by LDPC coding is analyzed through simulation.At the same time,several antenna systems for anti-interference in the airspace are introduced.(2)Under the direct spread spectrum communication system,the common types of narrow-band interference are listed,and the anti-jamming performance of several commonly used narrow-band interference suppression technologies is analyzed through experiments.The bit error rate graph is given through computer simulation,and the differences are compared.Performance of narrow-band interference suppression technology.In addition,combined with the deep learning neural network,use pure signal information as the target to train the network,and then use the trained neural network to learn and classify the received signal to achieve a filtering effect and to suppress narrowband interference.(3)Under the channel with frequency and phase offset,the BER performance of the BPSK modulation and demodulation method and the 2FSK modulation and demodulation method are studied and compared,and combined with the multi-dimensional domain antiinterference technology,the workflow of the entire communication system is given.It mainly includes LDPC coding and 2FSK modulation and demodulation.And build an antijamming communication system on ALTER's FPGA,perform performance tests on the system,record its interference tolerance under different intensity interference,and verify its anti-jamming capability. |
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