摘要
在对导航卫星卷积码序列应用MAP算法译码时,计算机会产生数值稳定性问题,输出错误的译码误码率,进而对定位结果的有效性和定位精度产生重要影响。针对该问题进行了具体分析,并对算法进行了改进,给出了一种基于最大状态度量的归一化MAP译码算法,在保持原算法最优性能的同时很好地解决了数值稳定性问题。通过仿真进一步验证了这种改进算法的有效性。
Computers may encounter the problem of numerical instability and output a wrong bit error rate （BER） when decoding navigation satellite convolutional codes with the maximum a posteriori probability （MAP） algorithm. Subsequently, this will affect the validity and the accuracy of the posi- tioning results. To address this problem, first a detailed analysis was executed. Based on this analy- sis, an improved MAP algorithm normalized with the maximum state metric is proposed, thus the question of numerical instability can be solved while still maintaining the original algorithm＇s optimal performance. Simulations further validate the effectiveness of this algorithm＇s improvement.
出处
《武汉大学学报（信息科学版）》
EI
CSCD
北大核心
2014年第3期267-270,共4页
Geomatics and Information Science of Wuhan University
基金
中国航天科技集团公司卫星应用研究院创新基金资助项目(20121512)~~
关键词
导航卫星卷积码
MAP译码算法
数值稳定性
最大状态度量
navigation satellite convolutional codes MAP decoding algorithm numerical stability maximum state metric
