基于时空二维MUSIC算法的DOA估计及其硬件实现方法研究

发布时间：2018-04-05 19:16

本文选题：时空二维MUSIC算法　切入点：FPGA+DSP实现　出处：《西安电子科技大学》2014年硕士论文

【摘要】：本文采用14个阵元组成的均匀线阵作为天线阵列模型,以时空二维MUSIC算法以及测距原理为理论,对测频测向设备的实现进行了研究。首先,使用Matlab进行了仿真。从仿真结果中得到了时空二维MUSIC算法在均匀线阵模型下的角度分辨率,确定了影响测距和测向精度的参数。验证了此方案在给定模型、参数下理论上的可行性。其次,为了进行硬件实现,对时空二维MUSIC算法进行了降维处理。首先对得到的差频信号做1024点FFT变换,得到1024个频点,接着对需要的频点用一维MUSIC算法进行处理。在对一维MUSIC算法的实现过程中,将它分成了协方差矩阵的估计、特征值分解、目标信号个数估计和谱峰搜索四个模块。降维处理后的时空二维MUSIC算法虽然避免了在频率、方向上同时进行搜索,但是计算量仍然很大,算法实现复杂。针对此问题,本文最终选择FPGA和DSP协作作为硬件实现方案。FFT变换、协方差矩阵的估计数据量大,且很规则,因此由FPGA完成。而协方差矩阵的特征值分解、目标信号个数估计、谱峰搜索的实现过程复杂,因此在DSP中完成。为了满足实时性的要求,同时也基于芯片资源和处理速度的考虑,本设计的FPGA芯片选用了Altera的Arria V,DSP芯片采用了TI的TMS320C6455芯片。DSP与FPGA之间主要通过EMIFA接口进行通信。FPGA部分采用了乒乓操作、流水线、状态机等方法来进行控制和提高算法的处理速度,并且考虑到该设计对实时性要求很高,多数情况下牺牲面积来换取速度。由于特征值的分解、信号源个数的估计方法很多,因此,对各处理算法进行了分析,在保证能达到要求的精度和分辨率的前提下,DSP部分选出了最适合的方案。比如,信号源个数这一参数的获得采用MDL准则完成,协方差矩阵的分解采用QR算法完成。各部分算法、硬件之间相互配合,FPGA部分给出了FFT变换和得到的协方差矩阵部分的SigtapII的测试结果,DSP部分给出了实现算法的流程图。所有算法的实现都在器件上做了测试,能够成功运行。基本上完成了基于时空二维MUSIC算法的障碍物的测距测向的分辨率、精度和实时性的要求。
[Abstract]:In this paper, a uniform linear array composed of 14 array elements is used as the antenna array model, and the realization of frequency and direction finding equipment is studied based on the space-time two-dimensional MUSIC algorithm and the principle of ranging.First, Matlab is used to simulate.From the simulation results, the angular resolution of the spatio-temporal two-dimensional MUSIC algorithm under the uniform linear array model is obtained, and the parameters affecting the ranging and direction finding accuracy are determined.The theoretical feasibility of this scheme under given model and parameters is verified.Secondly, in order to implement the hardware, the dimension reduction of the two-dimensional MUSIC algorithm is presented.First, the difference frequency signal is transformed by 1024 points FFT, and 1024 frequency points are obtained. Then, the needed frequency points are processed by one-dimensional MUSIC algorithm.In the implementation of one-dimensional MUSIC algorithm, it is divided into four modules: covariance matrix estimation, eigenvalue decomposition, target signal number estimation and spectral peak search.Although the dimensionally reduced two-dimensional MUSIC algorithm avoids simultaneous search in frequency and direction, the computation is still very large and the algorithm is complex.In order to solve this problem, this paper chooses FPGA and DSP cooperation as the hardware implementation scheme. The covariance matrix estimation data is large and regular, so it is completed by FPGA.The eigenvalue decomposition of the covariance matrix, the estimation of the number of target signals, and the implementation of the spectral peak search are complex, so they are completed in DSP.In order to meet the requirements of real-time, but also based on chip resources and processing speed considerations,The FPGA chip of this design uses Altera's Arria VN DSP chip to use TI's TMS320C6455 chip .DSP and FPGA to communicate mainly through EMIFA interface. The part of the design adopts ping-pong operation, pipeline, state machine and other methods to control and improve the processing speed of the algorithm.And considering that the design requires high real-time, in most cases sacrificing the area for speed.Because of the decomposition of the eigenvalue, there are many methods to estimate the number of signal sources. Therefore, the processing algorithms are analyzed, and the most suitable scheme is selected under the premise that the required precision and resolution can be achieved.For example, the number of signal sources is obtained by MDL criterion and the decomposition of covariance matrix by QR algorithm.The FFT transform and the test result of the covariance matrix part are given. The flow chart of the algorithm is given.All the algorithms are tested on the device and can run successfully.The resolution, accuracy and real-time requirements of obstacle ranging and direction finding based on spatio-temporal MUSIC algorithm are basically fulfilled.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN820.15;TN911.7

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