Configurable Multi-Band GNSS Receiver for Robust Handheld Devices

Santiago Urquijo, Fabio Garzia, Alexander Popugaev, Alexander Rügamer, Wolfgang Felber

Abstract:	This research presents a configurable multi-band dual-path GNSS receiver architecture, incl. the antenna, realized in a demonstrator that allows the receiver to adapt its performance depending on the circumstances, significantly reducing overall power consumption or enhancing its interference robustness. A new dual-path RF topology is proposed to improve the receiver’s power efficiency. In contrast to typical GNSS antennas in common smartphones, which are mainly linearly polarized, the proposed antenna consists of four compact SMD edge-mounted antenna elements and a quasi-quadrature feed network providing proper magnitude and phase distributions for reception and separation of right-hand and left-hand circularly polarized signals. The prototype created for the evaluation consists of a 70 mm x 150 mm wide-band antenna (capable of L1/E1, L2, E6, and L5/E5, even incl. very wide-band signals like AltBOC), a dual-channel Radio Frequency (RF) front-end based on the ASIC PASCAL [1], and a Xilinx MPSoC ZynQ Ultrascale+ FPGA, including the baseband processing and receiver software. This platform was chosen to be able to experiment easily with different configurations. The PASCAL-V2 ASIC has been manufactured in a GlobalFoundries 55 nm CMOS process technology and accepts different configurations on two frequency bands. The Integrated Circuit (IC) is packaged in a 6 mm x 6 mm QFN48 housing with an exposed paddle. It is possible to set a low-power operation employing a low quantization of the RF signals, which is enough to achieve excellent performance in most scenarios. The IC includes two independent PLLs and two configurable 4-bit analogto-digital converter (ADC) (one ADC per channel) at a maximum clock of 250 MHz. Moreover, differential analog outputs of the intermediate-frequency (IF) signals have been added that can be combined with external components such as high-speed, high-resolution ADC. In this demonstrator, two hardware configuration modes have been realized: a low-power mode using the internal 4 bit ADCs and, alternatively, a high resilience mode, where an external ADC (providing a considerable higher quantization) and a digital mitigation core (high-rate DFT-based data manipulator (HDDM) mitigation [2]) are used to improve the receiver’s performance in jamming scenarios. The receiver can detect the conditions in various situations and decide which mode is necessary to achieve a reliable and accurate localization. If no jamming is present, the low-power mode is chosen in which a Low Noise Amplifier (LNA) and the PASCAL IC are active at the front-end. In cases jamming is present, an external variable gain amplifier (VGA) or amplifier and a high resolution ADC improve the signal quality, providing sufficient dynamics and linearity to make the digital interference mitigation effective. Experimental results of the prototype L1/E1 and L5/E5 GPS/Galileo handheld receiver with and without jamming are shown in the paper. One prototype was prepared, including E1/E6 Pseudo-PRS Signals for evaluation of the receiver together with the antenna in the laboratory. This experiment used a radiated signal generated by the Spirent GNSS generator. An additional prototype was prepared for L1/E1 and L5/E5 reception. In this case, Signal-in-Space GNSS signals were used for evaluations. Preliminary results of field tests have shown that the new antenna concept enables significantly better performance in terms of position accuracy and availability. This will pave the way for new PNT services in harsh environments where it would not have previously been possible.
Published in:	Proceedings of the 36th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2023) September 11 - 15, 2023 Hyatt Regency Denver Denver, Colorado
Pages:	3432 - 3446
Cite this article:	Urquijo, Santiago, Garzia, Fabio, Popugaev, Alexander, Rügamer, Alexander, Felber, Wolfgang, "Configurable Multi-Band GNSS Receiver for Robust Handheld Devices," Proceedings of the 36th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2023), Denver, Colorado, September 2023, pp. 3432-3446. https://doi.org/10.33012/2023.19241
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