FMCW车载毫米波雷达空时码信号处理方案

A Space-Time Coding Based Signal Processing Scheme for FMCW Automotive Millimeter-Wave Radar

空时分组码是无线通信系统中的一种抗信道衰落和提高系统容量的编码方法,能够同时获得分集增益和编码增益。由此将MIMO通信和MIMO脉冲雷达中应用较多的空时分组码引入FMCW车载毫米波雷达信号处理中,通过对发射信号和接收信号的编码解耦,形成更大天线孔径的虚拟阵列,提高了系统角度分辨率。相比于基于时间分集的虚拟阵列算法,基于空时分组码的虚拟阵列算法能够在单天线功率受限的场景下,获得多根天线同时工作带来的功率增益。同时,针对空时分组码中目标运动带来的相位误差问题,根据FMCW车载毫米波雷达低复杂度的系统需求,设计了一种适用于相干目标的运动相位校准算法。仿真结果表明,基于空时分组码的FMCW车载毫米波雷达信号处理算法相比于已有算法能够获得更好的系统性能。

Space-time block code is generally used in wireless communications for mitigating the channel fading and improving the system capacity via achieving diversity and coding gains simultaneously.In this paper,the space-time block codes used in MIMO communications and pulse radars are utilized in signal processing for FMCW automotive millimeter-wave radars.Via decoupling the encoded receiving signals to form a virtual array with larger antenna aperture,the space-time block codes can help increase the system angular resolution.Compared with the virtual array formed by time diversity,the proposed space-time block code based scheme can achieve the power gain by the simultaneous transmitting of multiple antennas under the power constraint of single antenna.Meanwhile,for the phase error caused by target motion in space-time block code,and according to the low complexity system requirements of FMCW automotive millimeter-wave radars,a motion phase calibration algorithm is proposed which is effective for coherent targets as well.Simulation results show that the proposed space-time block code based scheme has better system performance compared with the existing schemes.