Unified Evaluation of Positioning Measurements in LEO-HAPS-BS Networks under Doppler Effects

Paper in proceeding, 2026

Non-terrestrial 6 G networks combining low earth orbit (LEO) satellites, high-altitude platform stations (HAPS), and terrestrial base stations (BS) promise high-precision positioning, but fair cross-tier benchmarking remains difficult under UE synchronization offsets and platform-dependent Doppler. We develop a unified discrete-time observation model for all three links, explicitly capturing both slow-and fast-time Doppler. To mitigate angle-of-departure (AoD)-Doppler coupling in multipath beam-sweeping, we apply a repetitive precoding phase profile that separates Doppler-induced frequency shifts from angular parameters. Using a common geometric environment with representative system settings, simulations quantify delay, Doppler, and AoD estimation accuracy. Results identify the excess transmit-power regime, precoding strategy, and Doppler prior quality as dominant performance drivers.