Reducing Range Sidelobes and Ghost Targets in PMCW Radars With π/K-Zadoff Code Sequences

This paper proposes a solution to reduce the range sidelobes and ghost targets in PMCW radars by improving the Zadoff sequences with the help of a progressive phase rotation. First, we show that the proposed code sequences, named
$\pi /K$
-Zadoff, are robust to IQ imbalance, DC offset and baseband third order non-linear distortions. We provide the criteria to select the values of
$K$
which minimize the range sidelobes produced by those non-idealities. Then, we show how to attenuate the remaining range sidelobes due to other transceiver analog front-end non-idealities by changing the transmitter code sequence every slow time repetition. This technique will be adapted to the specific case of Zadoff sequences to preserve two of their properties: the robustness to Doppler frequency shift and power amplifier non-linearity. The resulting PMCW radar is able to achieve low sidelobes even in presence of front-end non-idealities and moving targets. We demonstrate the effectiveness of our methods by simulation with a realistic automotive scenario.