PN code tracking based on sub-Nyquist and non-commensurate sampling

• Published in: Electronics letters Vol. 56; no. 14; pp. 734 - 736
• Main Authors: Jin, Xiaojun, Peng, Zhen, Ma, Zhipeng, Zhang, Wei, Xu, Zhaobin, Jin, Zhonghe
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 09.07.2020
• Subjects: autonomous RF ranging signal design; high‐bandwidth signals; high‐precision autonomous PN ranging; high‐signal‐to‐noise ratio conditions; navigation signals; necessary condition; noncommensurate sampling; Nyquist criterion; Nyquist sampling theorem; PN code tracking approach; pseudonoise codes; pseudonoise ranging accuracy; radio tracking; satellite navigation; Signal processing; signal sampling; subNyquist sampling; system design; thermal noise; tracking error; tracking error; autonomous RF ranging signal design; high-signal-to-noise ratio conditions; radio tracking; system design; pseudonoise codes; navigation signals; necessary condition; pseudonoise ranging accuracy; noncommensurate sampling; high-precision autonomous PN ranging; PN code tracking approach; subNyquist sampling; signal sampling; Nyquist sampling theorem; Nyquist criterion; satellite navigation; high-bandwidth signals; thermal noise
• ISSN: 0013-5194; 1350-911X; 1350-911X
• DOI: 10.1049/el.2020.0552

Increasingly high bandwidths are desired in modern navigation and autonomous RF ranging signal design to achieve better pseudo-noise (PN) ranging accuracy. However, fulfilling the Nyquist criterion for such high-bandwidth signals would be a challenging issue for system design. Considering that the Nyquist criterion is not a necessary condition for PN code tracking, sub-Nyquist sampling can be adopted as a feasible solution to this issue. Nevertheless, it is at the expense of an increase in thermal noise caused by tracking error. This problem is particularly prominent for tracking weak signals such as navigation signals, which limits the applicability of this sampling scenario. As far as high-precision autonomous PN ranging is concerned, however, the tracking error due to digital implementation is not negligible and even becomes the dominating factor instead of thermal noise. This means that the performance loss incurred by sub-Nyquist sampling can be eliminated under high-signal-to-noise ratio conditions. Exploiting this fact, this Letter proposes a novel PN code tracking approach based on sub-Nyquist and non-commensurate sampling, providing a solution to achieving high-ranging accuracy while breaking the bounds of the Nyquist sampling theorem without performance degradation. The approach is very attractive for precise PN ranging applications demanding miniaturised implementation.