  Quadrature compressive sampling (QuadCS) is a newly introduced sub-Nyquist
sampling for acquiring inphase and quadrature (I/Q) components of
radio-frequency signals. For applications to pulse-Doppler radars, the QuadCS
outputs can be arranged in 2-dimensional data similar to that by Nyquist
sampling. This paper develops a compressive sampling pulse-Doppler (CoSaPD)
processing scheme from the sub-Nyquist samples. The CoSaPD scheme follows
Doppler estimation/detection and range estimation and is conducted on the
sub-Nyquist samples without recovering the Nyquist samples. The Doppler
estimation is realized through spectrum analyzer as in classic processing. The
detection is done on the Doppler bin data. The range estimation is performed
through sparse recovery algorithms on the detected targets and thus the
computational load is reduced. The detection threshold can be set at a low
value for improving detection probability and then the introduced false targets
are removed in the range estimation stage through inherent detection
characteristic in the recovery algorithms. Simulation results confirm our
findings. The CoSaPD scheme with the data at one eighth the Nyquist rate and
for SNR above -25dB can achieve performance of the classic processing with
Nyquist samples.
