Summary: | Switch antenna array (SAA) frequency modulated continuous-wave (FMCW) radar has garnered a great deal of research attention in recent years due to its low cost and small volume. The phase shift caused by a target's movement may lead to an inaccurate estimation of the target's direction. A direction estimation method for moving targets with low signal-to-noise ratio (SNR) is proposed in this paper for SAA FMCW radar applications. In the proposed method, digital beam forming (DBF) is applied twice. The improvement of the SNR of the echo signal is implemented by the first DBF. Meanwhile, the synthesized signal is used for distance and velocity estimation. The estimated velocity is then used to complete the phase compensation of the moving target. Finally, the direction estimation is implemented by the second DBF. The feasibility of the method is validated by numerical and experimental results. This method avoids the use of optimization algorithms and does not require eigenvalue decomposition calculations, which ensures its applicability under strict real-time requirements.
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