Multilevel Coded Spreading Symbol Optimization Accounting for Ionospheric Dispersive Effects

Kurzfassung

Distortion-aware ranging signal design aims to mitigate model mismatch caused by cumulative transmitter, receiver, and propagation distortions that deform the cross-correlation function (CCF) and ultimately degrade ranging performance. Existing frameworks incorporate measured payload and receiver distortions, but typically assume an idealized propagation channel characterized solely by path loss. In the context of wideband signal design for satellite navigation systems, this assumption neglects the dispersive nature of the ionosphere, whose frequency dependent behavior distorts the CCF. This paper addresses this gap by integrating an ionospheric filter into a distortion-aware ranging signal design framework. The resulting correlation loss is quantified for wideband legacy and Pareto-optimal, distortion-optimized multilevel coded spreading symbol (MCS) signal candidates. The results demonstrate that distortion-optimized signal candidates exist that jointly reduce code tracking jitter by 37% and ionospheric correlation loss by 64% compared to a BPSK(10) signal on L5 used as a reference. However, achieving more substantial reductions in code tracking jitter of over 65% requires accepting an increase in ionospheric correlation loss of more than 126%, highlighting a fundamental trade-off between ionospheric dispersion robustness and tracking performance.