Multiband complementary dual-chirp waveform for the simultaneous range and velocity detection

We propose an approach to realize a photonic frequency-modulated continuous wave radar for simultaneous range and velocity detection with high accuracy using multiband complementary V-shaped chirps. In this approach, the direction of motion of the target is estimated directly from a low-bandwidth spectrum of de-chirped frequencies, which significantly reduces the requirement for complex digital signal processing and high-speed analog-to-digital converters. Experiments have been conducted in emulation to validate the concept. The range and velocity have been estimated with an accuracy of 50 cm in range and 0.7 m/s in velocity for a target at 100 m moving with a velocity of 60 m/s. Further, experiments have been carried out to estimate the velocity of a toy car with an accuracy of 0.3 m/s. Moreover, the generation of the multiband complementary dual-chirp waveform has been demonstrated using a dual-polarization dual-parallel Mach-Zehnder modulator. We have also illustrated an inverse synthetic aperture radar imaging of two rotating targets using a down-chirp linear frequency-modulated signal with the same receiver setup. The high-resolution imaging with the estimation of range and cross-range is experimentally achieved with an error of <4cm.