Photonic-based radar for distance and velocity measurement with multiformat waveforms

Abstract

A radar with multiformat waveforms is proposed to measure distance and velocity. A dual-polarization, dual-parallel Mach–Zehnder modulator (DP-DPMZM) is used to realize carrier-suppressed single-sideband (CS-SSB) modulation, so the switchable down-, up-, and dual-chirp signals, and the amplitude shift keying (ASK) signal, can be generated. The central frequency and bandwidth of the signals are flexible. A Mach–Zehnder modulator (MZM) is added for an optical switch to realize the generation of a pulsed signal and suppress interference in the dechirping process. A dual-drive MZM (DDMZM) is used for the dechirping process. The key component of this radar is that there are no filters used, which can significantly extend the operation bandwidth. In our test, the interference frequency caused by the CW can be suppressed. The error of the distance measurement is less than 2 cm, and the velocity error is less than 0.180 m/s. In addition, the direction of the target can be distinguished.