基于OTFS-NOMA的低轨卫星通信与导航一体化传输方法研究OA

In Low Earth Orbit(LEO)satellite downlink communications,severe Doppler shifts and rapidly time-varying multipath fading caused by the high-speed movement of satellites pose significant challenges to LEO system design.Meanwhile,the networked deployment of LEO mega-communication constellations offers opportunities for the development of LEO-based navigation capabilities.To address this issue,an integrated communication and navigation transmission scheme is proposed based on Orthogonal Time Frequency Space(OTFS)modulation and Non-Orthogonal Multiple Access(NOMA).In the proposed approach,communication symbols and navigation signals are superimposed in the Delay-Doppler(DD)domain using power-domain multiplexing,while the entire frame is filled with Pseudo-Noise(PN)sequence serving as the pilot signal.A sliding matched filter is employed to estimate the sparse channel,and a coarse Doppler estimation mechanism is introduced to mitigate dynamic drift resulting from the inherent high Doppler distortion in satellite-to-ground links.Simulation results demonstrate that under typical link conditions,the proposed OTFS-NOMA integrated architecture achieves a two-order-of-magnitude reduction in Bit Error Rate(BER)compared with conventional Orthogonal Frequency Division Multiplexing(OFDM),and enables pseudorange measurement accuracy of 2.18 m.