Near-field UWB impulse ranging based on a broadband nonlinear optoelectronic oscillato

An ultra-wideband (UWB) impulse ranging scheme is proposed and demonstrated based on a broadband nonlinear optoelectronic oscillator (OEO). An external low-speed square-wave signal is injected into the OEO cavity to trigger generation of an UWB pulse train with excellent pulse-to-pulse coherence. The generated UWB pulse train is transmitted and received by using a pair of antennas to achieve near-field detection. Benefitted from the high pulse-to-pulse coherence, the poor signal-to-noise ratios (SNRs) of the echo signals from the targets are improved after coherent accumulation. Then, the target locations are extracted by employing correlation and subtracting background interference. In the experiment, an UWB pulse train with a pulse width of 0.44 ns and a period of about 45 ns is generated. Based on the generated UWB pulse train, two targets located 21 cm apart are clearly distinguished in near-field ranging.