Page 13 - ITU Journal: Volume 2, No. 1 - Special issue - Propagation modelling for advanced future radio systems - Challenges for a congested radio spectrum

ITU Journal: ICT Discoveries, Vol. 2(1), December 2019

LIST OF ABSTRACTS

A powerful signal nearby L1 frequency band jamming GNSS stations in
Observatoire de Paris

Pages 1-8

Pierre Uhrich, Michel Abgrall, Franziska Riedel, Baptiste Chupin, Joseph Achkar, G. Daniele Rovera
In the frame of the French metrology organization, the laboratory Systèmes de Référence Temps-Espace
(SYRTE) in Observatoire de Paris (OP) is in charge of fundamental activities in the time and frequency domain.
Among other systems, the laboratory is operating stations receiving signals from global navigation satellite
systems (GNSS) like the Global Positioning System (GPS) or Galileo, aiming at accurate time transfer with
other remote time laboratories. Since November 2018, the GNSS signal reception in the L1-band has been
jammed by a powerful signal transmitted near to OP in a frequency band allocated to space to Earth satellite
telecommunication. This signal power was originally more than 35 dB above the GNSS spread-spectrum
power level. A formal complaint was raised in early January 2019 to the Agence Nationale des Fréquences
(ANFR). The paper describes the jamming signal and its consequences. The effect of this signal on L1-band
reception was not the same on all OP stations, depending on the bandwidth of the antenna around the L1 carrier,
but also on the receiver’s different types. It went from no effect at all for GPS-only stations to large data loss
and noise increase for multi-GNSS stations. The power of the jamming signal is changing with time and
remains under observation. We discuss what might be done to overcome this issue.
View Article

A quick overview of a new scintillation database

Pages 9-15
Ana Pinho, Susana Mota, Armando Rocha
This paper explores a new Ka and Q-band dry scintillation database and ancillary meteorological data collected
at Aveiro, Portugal in two converging Earth-satellite propagation paths. The measurement equipment, the
parameters of both links and the processing procedure of the database are described first. The dependencies of
the hourly averaged scintillation standard deviation with respect to several meteorological parameters,
measured at the ground level, and with respect to the wet refractive index are analyzed. The diurnal variation
of the hourly averaged scintillation standard deviation, on a monthly and yearly basis, is explored. The yearly
amplitude distributions, fades and enhancements, are presented and compared against some available models.
The scatter plot of the concurrent hourly averaged scintillation standard deviation is analyzed and a frequency
scaling factor is tentatively derived.

View Article

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