Towards Single Antenna Phase-Coherent INS-Beamforming to Enable RTK with Low-End Antennas

Jürgen Dampf, Mohamed Bochkati, Thomas Pany

Abstract:	The sector of mass-market global navigation satellite system (GNSS) receivers experiences a continuous growth, and the demand for reliable and precise positioning becomes higher than ever, considering for example the increasing number of location based services (LBS) in smartphones or the field of autonomous driving (EUSPA, 2022). In these applications, size and shape of the antennas become subject to form-factor driven design, leading to degraded GNSS performance mainly caused by unfiltered multipath. Most GNSS receivers are already available loosely or tightly coupled with an inertial navigation system (INS) to improve the robustness and positioning performance, but precise positioning techniques like real-time kinematics (RTK) and Precise Point Positioning (PPP) still degrade when multipath is present. Nevertheless, a rarely investigated pure software based method, which is called synthetic aperture processing (SAP) or ”Supercorrelation”, is capable of purifying the GNSS observations from multipath on the tracking loop level. Thus, our overall target is the realization and evaluation of SAP in a newly developed MATLAB software receiver (MSRx) using both low and high-quality sensors, which unravels to three steps: At first, the implementation and analysis of a external Doppler-aided phase locked loop (PLL). Second, the realisation of an external carrier-range aiding of the PLL including co-operated (CO-OP)-tracking to estimate the receiver clock, and third, the increase of the coherent integration time, e.g., up to 1-2 seconds, to fully exploit the effect of SAP beamforming. The first step, i.e., the external Doppler-aided PLL, implicitly exploits the concept of SAP to a certain extent, when considering proper settings. Consequently, this stage can be seen as a simplest form of SAP. This work focuses on this rather trivial realization of SAP using an external Doppler aided PLL and discusses the achieved tracking performance and positioning results.
Published in:	Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022) September 19 - 23, 2022 Hyatt Regency Denver Denver, Colorado
Pages:	2202 - 2214
Cite this article:	Dampf, Jürgen, Bochkati, Mohamed, Pany, Thomas, "Towards Single Antenna Phase-Coherent INS-Beamforming to Enable RTK with Low-End Antennas," Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022), Denver, Colorado, September 2022, pp. 2202-2214. https://doi.org/10.33012/2022.18295
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