Research On Satellite Navigation Communication Link Anti-jamming Based On BOC Modulation

The safety and reliability of the communication link of satellite navigation system plays a very important role in modern communication electronic warfare.Only by establishing a secure and reliable communication link can we gain a favorable position in electronic warfare.However,due to the vulnerability of satellite navigation system,its security is not high,and the potential threat makes it difficult to operate normally in complex electromagnetic jamming.Therefore,it is of great significance to establish the communication link protection system of cognitive satellite navigation system.The communication link protection system of cognitive satellite navigation system consists of three modules: detection module,analysis module and protection module.Detection module is detection and identification jamming;The analysis module is to analyze the influence of jamming on the system.The protection module is based on the analysis module for system protection.Among them,the analysis module is the key to the communication link protection system of cognitive satellite navigation system.This paper studies BOC modulation and CBOC modulation,analyzes the influence of different interference on its communication performance,and establishes the analysis module of communication link protection system of cognitive satellite navigation system.The main contents are as follows:First,the anti-noise performance of BOC modulation and the bit error rate formula of BOC modulation under tone-jamming are derived and verified by simulation.For the widely used BOC modulation,the theoretical formula of the bit error rate in the AWGN channel and the theoretical formula of the bit error rate under singletone jamming and multitone jamming are derived.The correctness of the formula is verified through simulation.The conclusion that the bit error rate of the BOC modulation using different parameters is the same under the AWGN channel.At the same time,the anti-noise performance and anti-singletone jamming performance of BOC modulation and BPSK-R modulation are compared.Through simulation,it is found that the anti-singletone jamming performance of BOC modulation is better than BPSK-R modulation,but the anti-noise performance of the two is the same.Secondly,the formula of BOC modulation bit error rate under any mathematical form of additive jamming is obtained by derivation and verified by simulation.Because there are not only singletone jamming and multitone jamming in the actual environment,this paper further studies the BOC modulation performance under additive jamming in arbitrary mathematical form.The simulation proves that the theoretical formula of bit error rate for singletone jamming and multitone jamming.It is concluded that the degree of spectral overlap between BOC modulated signals and jamming directly affects the performance of the system.Finally,the BER formulas of CBOC modulation in different environments described in this paper are obtained by derivation and verified by simulation.It is promoted by BOC modulation,and research on CBOC modulation is carried out.By establishing a mathematical model,the theoretical formula of its anti-noise performance is derived.At the same time,the BER foumulas of CBOC modulation under tone-jamming jamming and additive jamming in arbitrary mathematical form are deduced.The theoretical formulas are verified by simulation.The research results in this paper provide ideas for the derivation of the bit error rate of other signal systems under jamming and provide references and basis for anti-jamming design for the further development of satellite navigation signals in the future.In conclusion,a solid foundation is laid for the construction of the communication link protection mechanism of the cognitive satellite navigation system by studying the BOC modulation and the CBOC modulation.