Photonics-based simultaneous measurement of distance and velocity using multi-band LFM microwave signals with opposite chirps

We propose and demonstrate a photonics-based method for simultaneously measuring distance and velocity by adopting multi-band linear-frequency-modulated microwave signals with opposite chirps as transmitted signals. A dual-drive Mach-Zehnder modulator and photodetector (PD) are used to mix transmitted and echo signals. By analyzing the electrical spectra of the electrical signals generated by the PD, distance and the magnitude and direction of velocity can be derived simultaneously, which is significant for real-time radar applications. Proof-of-concept experiments using the proposed approach are also presented. The measured relative errors for distance and velocity are less than 0.005% and 0.59%, respectively. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement