| Due to the existence of strong targeted interference technology, as well as the vulnerable to interference of the satellite signal itself, anti-interference technology is indispensable in satellite communication systems. Adaptive algorithm is applied not long in the field of anti-interference, which is one of the research priorities. It is introduced in radar system first,and used in satellite system later, so there are still many characteristics needs to be improved,such as the convergence speed, computational complexity, interference suppression degree and so on. Aimed at the above aspects, recursive least squares (RLS) and direct sampling matrix inversion (SMI) were also studied deeply with the research projects together in this paper.The algorithm simulation platform mode was established first from the three aspects---characteristics of the satellite signal, the array configuration of receiving antenna and the pre-processing mode. Then, the airspace anti-interference technology, the two adaptive algorithms (RLS and SMI) and their improved algorithm were analyzed and simulated on this platform. Combined with the principle of derivation and the simulation results, the paper compared the convergence degree and interference suppression degree of the four algorithms,in order to explain the superiority of the improved algorithm in the hardware engineering applications.Secondly, combined with the anti-interference technology in space-time domain, fast Fourier transform was used to change the signals from time domain to frequency domain and then processed the signals respectively. in order to reduce the complexity of the alogorithm.The gain of the antenna signal was improved by digital multi-beam technology in airspace, so as to improve the number of anti-interference antenna array, that is increasing the freedom degree, and also reduce the complexity of the adaptive algorithm while improving the antenna gain of the received signal.Finally, the space-frequency adaptive algorithm was applied in hardware. VHDL hardware language was used to verify the effectiveness of the every mode of the algorithm,with the help of Xilinx’s FPGA development software ISE12.4 and MATLAB co-simulation platform. |
