Indirect learning Hammerstein HPA predistorter for wideband GNSS signals
- PDF / 3,187,257 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 96 Downloads / 214 Views
ORIGINAL ARTICLE
Indirect learning Hammerstein HPA predistorter for wideband GNSS signals Ningyan Guo1,2 · Zheng Yao1,2 · Mingquan Lu1,2 Received: 14 February 2020 / Accepted: 1 October 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Compared with the traditional GPS L1 C/A signal, the existing and emerging new-generation wideband GNSS signals suffer more severe distortions due to the nonlinear characteristics of a high-power amplifier (HPA) in the satellite transmitter. HPA nonlinearity can lead to in-band signal distortion and out-of-band spectral regrowth, which degrade the ranging performance of a GNSS receiver. Researchers have reported power loss, correlation peak asymmetries, lock point bias as well as carrier tracking error caused by the HPA nonlinearity. However, few pre-distortion approaches that compensate for the HPA nonlinear effects have been presented in the GNSS field. We first take BDS-3 B2 asymmetric constant envelope binary offset carrier signal as an example to present the HPA nonlinear effects on wideband GNSS signals. Then, the design principle of a predistorter is investigated, and a Hammerstein predistorter is proposed to eliminate the nonlinear HPA with memory. Finally, we compare the constellation diagram, power spectrum, correlation function, code tracking bias with and without the Hammerstein predistorter. The comparison results demonstrate that a digital predistorter is a potential solution to compensate the HPA nonlinear distortions for wideband GNSS signals. This pre-distortion approach is of great significance that can effectively guarantee the nominal signal quality in space not only during the maintenance of the current GNSSs but also for the future emerging local or global navigation systems. Keywords Wideband GNSS signals · HPA nonlinear distortions · Hammerstein pre-distortion
Introduction With the rapid development of global navigation satellite systems (GNSSs), especially China’s BeiDou Global system (BDS-3), a significant increase in the wideband GNSS signals (Lestarquit et al. 2008; Yao et al. 2016; Guo et al. 2016) is designed to meet diverse positioning, navigation, and timing (PNT) services for users, and ensure sufficient robustness for each service. Due to limitations in payload size, weight, and imperfect analog components, the newgeneration wideband GNSS signals in recent years employ the advanced constant envelope multiplexing (CEM) techniques to multiplex multiple signals into a composite signal within a single GNSS satellite. Examples are alternative * Zheng Yao [email protected] 1
Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
Beijing National Research Center for Information Science and Technology, Beijing 100084, China
2
binary offset carrier (AltBOC) (Lestarquit et al. 2008), phase-optimized constant-envelope transmission (POCET) (Dafesh and Cahn 2009), and asymmetric constant envelope binary offset carrier (ACE-BOC) (Yao et al. 2016). These advanced constant envelope signals ca
Data Loading...
