Jia Ruochen, Li Yunxiao, Qu Daiming
School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan 430074, China.
Sensors (Basel). 2025 Jul 26;25(15):4638. doi: 10.3390/s25154638.
The enhanced Loran (eLoran) system, a critical terrestrial backup for the Global Satellite Navigation System (GNSS), traditionally utilizes a Reed-Solomon (RS) code for its data communication, which presents limitations in error performance, particularly due to its decoding method. This paper introduces a significant advancement by proposing the replacement of the conventional RS code with a 128- polar code, which is designed to maintain compatibility with the established 128- Pulse Position Modulation (PPM) scheme integral to eLoran's positioning function. A Soft-Soft (SS) demodulation method, based on a correlation receiver, is developed to provide the requisite soft information for the effective Successive Cancellation List (SCL) decoding of the 128- polar code. Comprehensive simulations demonstrate that the proposed 128- polar code with SS demodulation achieves a substantial error performance improvement, yielding an approximate 9.3 dB gain at the 0.01 FER level over the RS code in eLoran data communication with EPD-MD demodulation. Additionally, the proposed scheme improves data transmission efficiency-either reducing transmission duration by 2/3 or increasing message bit number by 250% for comparable error performance-without impacting the system's primary positioning capabilities.
增强型罗兰（eLoran）系统是全球卫星导航系统（GNSS）至关重要的地面备份系统，传统上其数据通信采用里德 - 所罗门（RS）码，该码在错误性能方面存在局限性，尤其是由于其解码方法。本文提出了一项重大进展，即用128极码取代传统的RS码，该极码旨在与eLoran定位功能所必需的已确立的128脉冲位置调制（PPM）方案保持兼容。基于相关接收器开发了一种软 - 软（SS）解调方法，以提供必要的软信息，用于对128极码进行有效的连续消除列表（SCL）解码。全面的仿真表明，所提出的采用SS解调的128极码在错误性能方面有显著提升，在与EPD - MD解调的eLoran数据通信中，在0.01误帧率水平下比RS码产生了约9.3 dB的增益。此外，所提出的方案提高了数据传输效率——在可比的错误性能下，要么将传输持续时间缩短2/3，要么将消息比特数增加250%——而不会影响系统的主要定位能力。
