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 参考文献:
 [1] Emre Kurtoglu, M. Mahbubur Rahman, "Direction of Arrival estimation with Virtual Antenna Array using FMCW Radar Simulated Data," github.
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 [2] J. Hasch, E. Topak, R. Schnabel, T. Zwick, R. Weigel, and C. Waldschmidt, “Millimeter-wave technology for automotive radar sensors in the 77 ghz frequency band,” IEEE Transactions on Microwave Theory and Techniques, vol. 60, no. 3, pp. 845–860, 2012.
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 [3] https://www.zhihu.com/people/tiaopig
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