Research And Implementation Of Adaptive System Identification-based Interference Cancellation

With the continuous development of radar and electronic countermeasure system, radaroften works as a network, and that makes electronic countermeasure system irradiated bymultiple radars. Higher requirements are put forward for electronic countermeasure system.Among the requirements, reconnaissance receiving and interference transmitting at the sametime have become very necessary aspect. Due to the restrictions of objective conditions, thedistance between transceiver antennas of the electronic countermeasure system cannot belarge enough. Simultaneous transmission and reception let strong interference signalcoupling into its own reconnaissance receiver. With the affection, the receiver cannot workproperly. In worse condition, the whole reconnaissance receiving system may be completelyparalyzed. Thus, eliminating the coupling interference signal to get effective transceiverisolation, has become a very important research topic.Firstly, the article briefly describes the background knowledge of the subject. The maintask of this project is to solve the transceiver isolation problem of electronic countermeasuressystem. The article also makes a comprehensive summary of the various technologies andmeasures currently taken to solve this problem. The analysis of the advantages anddisadvantages of these technologies is given, and the interference cancellation techniquebased on adaptive system identification is initially introduced.Secondly,the interference cancellation principle based on adaptive system identificationis introduced in detail and adaptive algorithms are discussed. Taking airborne electroniccountermeasure systems as the model, the article analyzes the characteristics of theinterference coupling path and the signal environment of the reconnaissance receiver. Thenan adaptive algorithm that can be sound and effective in actual complex and worseenvironment is proposed. The performance of the proposed algorithm is verified by usingMATLAB simulation. The simulation results show that the proposed algorithm has superiorconvergence performance than general variable step-size algorithms; and, whether it isunder the influence of noise in the receiver or strong radar signal, the proposed algorithmcan both have better performance,it also has strong ability against the nonlinear factors.Thus a good interference cancellation effect can be achieved in complex real environment.Finally, the interference canceller is realized on FPGA+DSP fusion architecture. Thecollection and cache of the data, data filtering processing and the circuit timing controlling are done by the FPGA. The adaptive algorithm is implemented by DSP. This article is mainlyresponsible for the DSP implementation of the adaptive algorithm. Optimization is alsomade according to the characteristics of the TI multicore DSP processor C6678to improvethe execution efficiency of the algorithm.