Blind Doppler Tracking and Beacon Detection for Opportunistic Navigation with LEO Satellite Signals

摘要

A Doppler tracking and beacon detection framework for blind opportunistic navigation (BON) with low Earth orbit (LEO) satellite signals is proposed. The BON framework cognitively deciphers partially known signals of opportunity (SOPs) and exploits them for navigation purposes. When only the bandwidth and length of an Mary phase shift keying (MPSK) SOP beacon is available, the BON framework enables acquisition and tracking of terrestrial and space-based SOPs in a blind fashion. A computationally efficient algorithm is presented to blindly detect the beacon signals and estimate the Doppler frequency. The BON framework is applied to decipher the C/A pseudorandom noise (PRN) sequences from four GPS satellites. The experimental results show that the BON framework is capable of cognitively detecting the PRNs of GPS satellites with a percentage of correctly detected chips ranging between 91 % and 99 %. Another experimental example with signals from two Orbcomm LEO satellites is presented, demonstrating an unmanned aerial vehicle (UAV) navigating via the BON framework. The UAV traversed a total trajectory of 782 m, achieving a position root mean-squared error (RMSE) of 21.2 m.