000004030 001__ 4030
000004030 005__ 20190131115555.0
000004030 037__ $$aCTALK-2019-0076
000004030 100__ $$aChevalier, Jean-Marie
000004030 245__ $$aNear-real time detection of solar radio burst impacting the GNSS signal reception
000004030 260__ $$c2016
000004030 269__ $$c2016-11-15
000004030 520__ $$aIntense solar radio bursts (SRBs) emitted at L-band frequencies can affect the carrier-to-noise density C/N0 of Global Navigation Satellite Systems (GNSS) signals by increasing the background noise. Such space weather events can consequently decrease the quality of GNSS-based results especially for kinematic high-precision positioning. Although solar observatories monitor the solar radio emissions, their direct impacts at the GNSS frequencies are not determined in real-time.  For this purpose, we developed at the Royal Observatory of Belgium (ROB) a method capable to detect SRBs based on real-time C/N0 observations from a regional GNSS (GPS+GLONASS) network. First, S1 and S2 raw data extracted from RINEX files were converted when necessary into the C/N0 unit (dB.Hz) taking into account manufacturer corrections. Then, the differences (∆C/N0) between these C/N0 observables and their medians of the 7 previous satellite ground track repeat cycles, i.e. their normal quiet state, were computed to remove the repeatable patterns (satellite elevation and multipath). Finally, the median <∆C/N0> from the regional GNSS network allows detecting and quantifying the impact of a SRB on GNSS signals quality at each frequency (i.e. L1 and L2). To validate this method, we investigated the degradation of GPS and GLONASS C/N0 on the entire EUREF Permanent Network (EPN) during 11 intense SRBs occurring between 1999 and 2015. The analysis shows that: (1) GPS and GLONASS ∆C/N0 agree at the 0.1±0.2dB.Hz level; (2) the standard deviation of the <∆C/N0> at L1 and L2 are stable and below 1dB.Hz 96% of the time; the least intense SRB was detected with 1 dB.Hz <∆C/N0> fade and the most intense SRB reached a <∆C/N0> fade of 12 dB.Hz; (3) maximum ∆C/N0 degradation occurs at the maximum solar peak flux delivered by the solar ground observatories; (4) C/N0 degradation becomes larger with increasing solar zenithal angle.  Consequently, the degradation of GNSS signal reception due to SRBs over Europe is now monitored at ROB in near real-time. With this new method, the SRB of the 4th November 2015 was already highlighted at the GNSS L2 frequency. In addition, first results of the method tested into other regions (Africa and South America) using the real-time network of the IGS will be introduced.
000004030 594__ $$aSTCE
000004030 700__ $$aBergeot, Nicolas
000004030 700__ $$aMarqué, Christophe
000004030 700__ $$aBruyninx, Carine
000004030 773__ $$tESWW13, Ostende, Belgium
000004030 8560_ $$fjean-marie.chevalier@observatoire.be
000004030 906__ $$aContributed
000004030 980__ $$aCTALKCONT