Performance analysis of the packet-based PNT service in NGSO broadband satellite communication systems

Providing alternative PNT service to GNSS-challenged users will be an important function of next-generation NGSO broadband satellite communication systems. Herein, a packet-based PNT service architecture in NGSO broadband systems is proposed in which a primary satellite and selected assistant satellites work together to provide PNT service to requesting users. Its positioning performance bounds are mathematically formulated by rigorously analyzing the bounds constrained by different waveforms. Simulations are conducted on different configurations of Walker Delta MEO constellations and Walker Star LEO constellations for corroboration, revealing the following: (1) Both MEO and LEO constellations achieve sub-meter-level positioning precision given enough satellites. (2) Compared to the GNSS Doppler-based velocity estimation method, the position advance based velocity estimation algorithm is more precise and applicable to the PNT service in NGSO broadband systems. (3) To provide PNT service to users in GNSS-challenged environments, the primary and each assistant satellite need only ∼0.1%o of the time of one downlink beam.