Joint optimization of spectral separation and navigation performance in GNSS signal design

In this work we present a systematic approach to design optimum chip pulse shapes for DS-CDMA systems which are strictly band-limited, whose energy is mainly concentrated in one chip duration, and that minimize the Cramer-Rao lower bound for time-delay estimation. The proposed methodology enables to formulate the problem of designing optimum chip pulse shapes in terms of achieving a trade-off between synchronization accuracy and acquisition and tracking robustness as an optimization problem. Additionally, spectral separation to non-interoperable signals in the same band is considered. This methodology uses the prolate spheroidal wave functions (PSWF) as basis functins in order to transform the primal variational problem into a dual, tractable parametric optimization problem. This work shows the interesting capabilities of the presented signal design approach for DS-CDMA systems. Further we show how two DS-CDMA signal components using optimized pulse shapes can be mapped/mulitplexed on one carrier frequency with low peak-to-average power ratio (PAPR). The presented approach is developed according to the needs of Galileo-2 signal design.