Research on Modulation Scheme for Low Earth Orbit Satellite Navigation Augmentation Signals Based on the L-Band

L-band dual-frequency broadcasting offers significant advantages in navigation augmentation, effectively reducing ionospheric errors, improving positioning accuracy, and enhancing system anti-interference capabilities. Currently, dual-frequency broadcasting predominantly uses CBOC modulation. However, CBOC's complex signal structure complicates receiver design, and its multipath resistance is limited in environments with strong multipath effects, such as urban canyons, where it is susceptible to interference from reflected signals, leading to reduced code tracking accuracy. Moreover, CBOC's large phase transitions increase the difficulty of phase tracking in the receiver, impacting the stability of signal acquisition and tracking. In response, this paper proposes an L-band dual-frequency broadcasting scheme based on BM1REC(2)h9.5. Compared to CBOC(6,1,1/11), this scheme maintains excellent compatibility while offering better code tracking accuracy and improved multipath resistance, contributing to further enhancements in LEO-based navigation augmentation system performance.