Time–frequency image-based carrier tracking method for Global Navigation Satellite System signal with ultra-high dynamics

摘要

Uncertainty principle has made the inevitable trade-off between achieving better frequency resolution and better time resolution in signal parameter estimation. High dynamics could make this problem even more challenging. In this study, the authors propose a novel tracking method for Global Navigation Satellite System (GNSS) signal carrier. Different from the single-domain tracking methods or Strapdown Inertial Navigation System, the presented method works in the time-frequency (TF) image generated by Wigner-Ville distribution. It has the ability to restrict the TF uncertainty to a small number of pixels around instantaneous frequency (IF) curve, which almost completely avoids the effect of high dynamics in its time/frequency estimation. The clear curve of the IF in TF image makes it possible to accurately estimate the instantaneous Doppler frequency and acceleration. Moreover, this estimation can be improved by image enhancement technique and image space transforms. Its ability of GNSS signal tracking is proved by the real signal static experiments. Simulation results show that the authors' method has the ability to track GNSS signal under at least 400 g dynamic stress in standard outdoor carrier-to-noise ratio.