A symbiotic FM radio data system (SRDS) refers to a kind of digital broadcasting whose signal co-exists with the FM in channel. The SRDS signal has a symmetrical split spectrum in the band of the host FM signal spectrum. Like the FM signal, this kind of broadcasting signal also has a wide range of ground coverage. When used as an alternative to the positioning, navigation and timing (PNT), it will be meaningful for intelligent artifacts in safety-of-life applications. However, SRDS signals not only have much narrower bandwidth than GNSS signals, but also multiple peaks of auto-correlation function, which poses a serious challenge to the time of arrival (ToA) estimation. In this paper, we propose a super-resolution ToA estimation algorithm for the SRDS signals. Specifically, the properties of the auto-correlation function of SRDS signal are deduced concretely, and a two-step ToA estimation algorithm for the SRDS signal is proposed accordingly. Simulations are conducted with different configurations of quantization bits, SNR, oversampling rates and multi-path. The results show that the meter-level ranging performance can be obtained in the single-path Gaussian channel, and the ranging performance degrades from tens of meters to a hundred meters in multi-path environments.

中文翻译：

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共生调频无线电数据系统的超分辨率到达时间估计

共生调频无线电数据系统（SRDS）是指一种数字广播，其信号与频道中的调频共存。SRDS 信号在主调频信号频谱的频带中具有对称的分裂频谱。与FM信号一样，这种广播信号也具有广泛的地面覆盖范围。当用作定位、导航和授时 (PNT) 的替代方案时，它将对生命安全应用中的智能人工制品具有重要意义。然而，SRDS信号不仅带宽比GNSS信号窄得多，而且自相关函数存在多个峰值，这对到达时间（ToA）估计提出了严峻挑战。在本文中，我们提出了一种用于 SRDS 信号的超分辨率 ToA 估计算法。具体来说，具体推导了SRDS信号自相关函数的性质，并据此提出了SRDS信号的两步ToA估计算法。使用量化位、SNR、过采样率和多路径的不同配置进行模拟。结果表明，在单径高斯信道下可以获得米级测距性能，在多径环境下测距性能从几十米下降到百米。