Interference Monitoring in the Central European GPS Geodynamic Reference Network

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Interference Monitoring in the Central European
GPS Geodynamic Reference Network

• István Fejes
• FÖMI Satellite geodetic Observatory
• Penc, Hungary

ESF Workshop on Active Protection of Passive
Radio Services towards a concerted strategy.
28-29 October 2004, Cagliary, Italy
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The use of GNSS for Earth sciences

• Presently the most important tool for monitoring
  tectonic processes beside VLBI and SLR
• Applied in Earth rotation and reference frame
  studies
• Atmospheric sciences
• water vapor content determination
• ionosphere studies
• All these are based on the operation of high
  precision GPS networks.
• High precision networks need high quality data
• RFI harmful to GNSS signals
• reduces S/N
• leads to rough positioning errors
• causes data loss
• inhibits measurements

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The Central Europe GPS Geodynamic Reference
Network (2003)
Epoch sites
Permanent sites
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The interference monitoring programme

• Monitor CEGRN sites regularly
• Collect and document user feed back
• Report interference to frequency management
  authorities
• Warn users

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The monitoring rules

• Equipment Advantest spectrum analyser
• Frequency bands
• Broad band 1-2 GHz
• GPS L1 1575.42MHz /- 15 MHz
• GPS L2 1227.6 MHz /- 15 MHz
• Galileo E5A-E5B, GPS L5 - 1164-1215 MHz
• Galileo E4, E6 1250-1300 MHz
• Galileo E2, L1, E1- 1550-1600 MHz
• Optionally high resolution tracks

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Checking Piszkésteto
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Example data files
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Conclusion

• GNSS RFI mapping
• Tool for site selection
• Assists site quality monitoring
• Assists GPS data reduction and analysis
• Warns GPS users of hot spots
• Alerts authorities
• Mitigate harmful consequences