The Study On The Interference Cancellation For Satellite Navigation And Concatenated LDPC/MIMO Systems

From the time navigation technogies was invented in the hunman history, the compass and acompasee is great inventions of ancient Chinese. Because of Chinese science and technology droppedbehind in the modern history, Chinese new navigation system was began to research and develop andestablish in the recent ten years, and it was a phased evolution of the satellite navigation system. Sothere are many key technologies and problems need to be solved and improved. And we both knowthe existence of interference and noise will increase the bit error ratio of the digital system and alsoreduce the performance of the whole system. So the technologies of adaptive anti-interference andinterference/noise suppression are one of the key technologies to improve the new navigation systemperformance.With the rapid development of mobile communication technology, multi-input multi-output(MIMO) technology is widely used in many systems. In the new navigation system, multiple inputsmean some satellite sources and interference sources and the noise sources. The transmitters send thesignals to the ground receivers through the MIMO channel. The receivers filter different signals bymultiple antennas. Finally the system makes sure that there are minimum interference and noise in allreceived signals.As we known, channel coding technology is most used to suppress the interference and noise.But the technology of channel coding has not been widely used when the GPS system was born. Andour country’s new satellite navigation system which just started referred to the GPS system in acertain extent. So it also doesn’t adopt efficient channel coding technology to suppress theinterference and noise.In the last section, MIMO technology and channel coding technology (for example, LDPC code)are magnitude bound together in order to form concatenated LDPC/MIMO Systems. This system hasbeen successfully applied to the new satellite navigation system, and achieves efficientanti-interference and reduces the noise in the new satellite navigation system.The main research work of thesis includes：1. Learning and understanding the structure of the GPS navigation system, then applying it to theChinese new satellite navigation system. 2. In the simulations for the multiple-input multiple-output (MIMO) system, studying and analyzingvarious factors which influence the anti-jamming performance and also doing the simulations byusing matlab language.3. In the spread spectrum MIMO model, when channel matrix has already known, doing thesimulations of all kinds of nonadaptive anti-interference algorithms by using computer languageand making the comparison and analysis of the performance. When the channel matrix hasunknown or not fully known, then putting forward the algorithms of full-blind channelanti-interference detection and half-blind channel anti-interference detection.4. In order to achieve the purpose of suppressing the interference and noise more efficiently, puttingforward the adaptive LMS-MIMO algorithm. The algorithm makes LMS algorithm from timedomain expand to the space domain and adaptively calculates error according to the input vectorand expectations in order to adjust filter coefficient.5. Studying the encoding and decoding technology and doing the simulations in order to get theperformance curve by using computer language under point to point environment.6. Combined with LDPC code and MIMO system in order to get the better performance ofsuppressing the interference/noise. After making the comparison with the traditionalmultiple-input multiple-output (MIMO) system, we find that the performance of concatenatedLDPC/MIMO Systems really better than the performance of the traditional multiple-inputmultiple-output (MIMO) system.