Test of the Filter Design Effect on Evil Waveform Monitoring in SBAS for Galileo E1 and E5a Signals

Ikhlas Selmi, Paul Thevenon, Christophe Macabiau, Olivier Julien, Mikael Mabilleau, Jaron Samson

Peer Reviewed

Abstract:	Evil Waveforms (EWF) are non-nominal distortions that can be observed on satellite signals and cause additional bias on the estimated user position. A Threat Model (TM) has been proposed by ICAO for GPS L1 C/A to describe the possible distortions that can be observed on the GPS signals [1]. This Threat model is also adopted for Galileo E1-C and E5a-Q signals. A previous paper focused on the Signal Quality Monitoring (SQM) design and compliance test for Galileo signals. In the present paper, the effect of the pre-correlation filter design applied at the aircraft and reference station receivers on the EWF induced bias and SQM compliance test is assessed. Two aspects of the filter design are considered: the filter center frequency shift due to temperature variation or electronic component aging, and the filter gain roll-off out of the filter bandwidth. The obtained results of EWF differential biases and SQM test in [2] are considered as the baseline results used to evaluate the effect on the tested filter parameters. This paper concludes on the tolerable center frequency offset and gain roll-off based on the comparison of the obtained EWF results for Galileo E1 and E5a to the baseline one.
Published in:	Proceedings of the 33rd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2020) September 21 - 25, 2020
Pages:	2398 - 2415
Cite this article:	Selmi, Ikhlas, Thevenon, Paul, Macabiau, Christophe, Julien, Olivier, Mabilleau, Mikael, Samson, Jaron, "Test of the Filter Design Effect on Evil Waveform Monitoring in SBAS for Galileo E1 and E5a Signals," Proceedings of the 33rd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2020), September 2020, pp. 2398-2415. https://doi.org/10.33012/2020.17657
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