  As the threats of small drones have grown, developing radars to detect the
small drones has become an important issue. In earlier studies, we proposed the
stationary point concentration (SPC) technique for the small drone detection
with frequency-modulated continuous-wave (FMCW) radar. The SPC technique is a
new approach to mitigate the leakage that is an inherent problem in the FMCW
radar. The SPC technique improves the signal-to-noise ratio of the small drones
by reducing the noise floor and provides accurate distance and velocity
information of the small drones. However, the SPC technique has shortcomings in
realizing it. In this paper, we present the drawbacks of the SPC technique
clearly and propose an advanced SPC (A-SPC) technique. The A-SPC technique can
overcome the drawbacks of the SPC technique while taking all the good effects
of the SPC technique. The experimental results verify the proposed A-SPC
technique and show its robustness and usefulness.
