Research On Algorithm And Implementation Technology Of Shortwave Wideband DF Based On Multicore DSP

Along with the development of shortwave communication technique,frequency hopping signal,tactical data link signal in the military shortwave communication system is used more and more often,so the direction finding of burst and short-time signal are more urgent.The research based on the implementation of HF wideband direction finding system,aiming at two key problems which are algorithm design and real-time realization,a wideband direction finding algorithm based on correlation interferometer is proposed and implemented on the multicore DSP of C66 x series.Along with the fast development of radio technology,signal direction finding technology has already laid a solid theoretical foundation,and has developed a variety of direction finding methods.By principle,it can be classified as phase interferometer DF(direction finding),correlation interferometer DF and amplitude comparison DF,spatial spectrum estimation DF,Doppler DF methods.These methods of direction finding each has its strong point,correlation interferometer direction finding system is highly recommended due to its high sensitivity,high accuracy and high noise immunity and other prominent features,and is particularly suitable for modern array data processing technology.According to the characteristics of direction finding system,this paper mentioned an ameliorative direction finding method based on correlation interferometer;on the one hand,an ameliorative cost function and parabola fitting algorithm is used to improve the direction finding precision.The amount of computation was reduced on the algorithm level and improved the accuracy of direction finding;on the other hand,Uses of phase difference vector accumulation improves the accuracy of phase measurement for low SNR(signal-to-noise)signal cases,and also improve the accuracy of low SNR signal direction finding.Meanwhile,the computation of correlation interferometer direction finding system is enormous.For the realization of HF wideband direction finding receiver,due to the need of using two-dimensional interferometer direction to find estimation both azimuth angle and pitching angle,and to achieve multiple sub channels direction finding at the same time,the amount of data to deal with is huge.To solve this problem,a wideband direction finding scheme based on high performance multicore DSP is proposed in this paper.According to the wideband direction finding process,an efficient hybrid parallel processing model was designed,its calculation speed is five times faster than single core calculation,at the same time,through the use of compiler optimization options,inline functions,restrict keywords and code optimization methods,the key code operation efficiency has been greatly improved,the overall speed is about twenty-two times faster.At present,the practical application of multicore DSP is still at stage of development,most domestic multicore DSP articles and papers focus on hardware and interface design;software programming especially software optimization technology such as algorithms decomposition,process control,parallel processing is hardly mentioned.The study of these aspects will help build a foundation of multicore DSP programming in the future.