Isochrons in Injection Locked Photonic Oscillators: A New Frontier for High-Precision Localization

For decades, high-accuracy localization has driven the interest of the research community. Recent cases include augmented reality (AR) and virtual reality (VR), indoor robotics, and drone applications, which have led to the emergence of subcentimeter localization requirements. This study introduces a new approach for high-accuracy localization by utilizing isochrons in injection-locked tunable photonic oscillators, which we referred to as Isochrons in Photonic Oscillators for Positioning (IsoPos). The proposed paradigm shift takes advantage of photonic oscillators' radical frequency tunability and isochron structure to offer an innovative path for measuring the time of arrival (ToA). To achieve precise ToA measurements, IsoPos utilizes the phase shift induced by the incoming user signal. This shift is detected by analyzing the phase response of the receiver, i.e., a photonic oscillator, which is exclusively determined by its isochrons' structure. Furthermore, IsoPos uses the injection-locking method as well as the nonlinear properties of injection-locked photonic oscillators to achieve highly accurate phase synchronization between different positioning nodes. This contributes to a seamless 3-D localization devoid of errors caused by miss-synchronization. Our numerical simulations show that IsoPos achieves sub-1 mm accuracy in 3-D localization, surpassing the precision of existing positioning systems by at least one order of magnitude.