Acquisition and Tracking of Starlink LEO Satellite Signals in Low SNR Regime

Acquisition and tracking of Starlink low Earth orbit (LEO) satellite signals in low signal-to-noise ratio (SNR) regime is considered. Starlink's highly dynamic downlink LEO signal model is derived, leading to coherence conditions for which the signals can be blindly tracked in low SNR regime. Next, the full-bandwidth Starlink beacon is estimated, and a time-bandwidth analysis of this beacon is presented. Finally, joint code and carrier phase Kalman filter-based loop is proposed for tracking Stralink LEO downlink signals in low SNR regime. Experimental results are presented showing successful Doppler tracking of 10 Starlink LEO satellites with a stationary receiver in low SNR regime. The Doppler observables were fused in a batch nonlinear least-squares estimator to yield a two-dimensional (2D) positioning error of 21.2 m, starting from an initial estimate 100 km away from the receiver's true position.