Research on UAV Positioning and Simulation Analysis Based on Space-Based Opportunistic Signals

To address the positioning requirements of unmanned aerial vehicles (UAVs) in GNSS-denied scenarios, this paper proposes a positioning scheme using low Earth orbit (LEO) satellites such as Iridium and Starlink as space-based opportunistic signal sources, combined with blind beacon estimation and Doppler tracking. This scheme leverages the complementary characteristics of multi-constellation signals, implements Doppler tracking via Kalman filtering, and fuses multi-constellation observations using nonlinear least squares. Simulation results show that the multi-constellation fusion positioning (zero baseline) error is as low as 5.1 meters, an improvement of over $\text{8 4 \%}$ compared to a single constellation; the Doppler tracking error is controlled within 10 Hz, and the convergence time is shortened by 40 % compared to a single constellation. This scheme can provide stable and reliable positioning services for UAVs in urban buildings, GNSS-denied and other scenarios, effectively solving the UAV navigation problem in GNSS-denied environments.