Velocity Estimation Algorithm Based on Staggered Subband Groups for DDMA-MIMO Radar

Doppler division multiple access-multiple input multiple output (DDMA-MIMO) radar performs well in long-range radar applications due to its high transmitted energy. However, the signal energy is defocused in the Doppler domain, so the detection performance will degrade in low signal-to-noise rate (SNR) scenarios. Meanwhile, the maximum velocity is reduced. Moreover, when multiple targets are located in the same range cell and their velocity difference is an integer multiple of the Doppler subband interval, the targets will overlap each other. In this letter, we propose a novel approach called staggered subband group DDMA (SSG-DDMA) to resolve the problem of target overlap. The proposed method changes the number of subbands in the Doppler domain by applying two different modulation phases at the transmitter. Then, the targets whose velocity difference is equal to an integer multiple of the subbands can be separated. Simulation results show the effectiveness of the proposed method.