Phase compression-holding modulation for C-band navigation

The modulation techniques for satellite navigation signals is important for performance such as signal ranging accuracy, spectral concentration, and multipath suppression. The signal design of the next-generation Global Navigation Satellite System (GNSS) should comprehensively consider these performance indicators and provide the optimal choice under specific engineering constraints. In order to achieve a trade-off between spectral concentration and ranging accuracy which are two key performance metrics, in this paper, a dual-channel orthogonal modulation technique based on continuous phase modulation (CPM) is proposed, namely phase compression-holding modulation (PCHM). The signal model, power spectrum characteristics and performance are investigated. The results show that when given a baseband phase pulse, this modulation technique can continuously control the out-of-band (OOB) power radiation and Gabor bandwidth of the signal by adjusting the holding length while preserving the beneficial properties of CPM such as phase continuity and constant envelope. Therefore, we can achieve a trade-off between the two indicators mentioned above and provide more flexible choices for specific problems in GNSS.