Interference Monitoring from Space

Interference Monitoring from Space

DESCRIPTION

A great number of civilian and military applications relies on GNSS for PNT, however its availability could be put at risk by threats such as local interference, amongst others.  GNSS spectrum monitoring is essential for:

  • detecting, characterising and localising interference sources, which could endanger the adequate reception and processing of GNSS signals; 
  • initiating a justified request process for interferer elimination;
  • warning in a timely way GNSS users exposed to the interference on the expected service degradation.

Ground-based monitoring stations can only provide coverage equal to the effective horizon of the station’s antennas (not taking into account blockage). In order to enable higher resolution localisation, these stations would also require sophisticated equipment to derive angle/direction of arrival and distance to interference sources.  Space-borne interference-monitors at LEO can be a very effective solution with a worldwide coverage, including monitoring of interference over sea. For instance, the number of ground-based monitors for a service over continental Europe would be very high compared to the required number of space-based monitors.  Moreover, monitors can also act as real-time warning beacons over affected areas. Flight experiments by means of a radio-occultation GNSS receiver on board the International Space Station (ISS) have been performed by the U.S. Naval Research Laboratory (NRL), and have demonstrated successfully the monitoring feasibility (“Serendipitous Observations of GPS Interference by GROUP-C on the ISS”). However, the topic is still unexplored to a large extent. Space-borne monitors offer very appealing features such as worldwide coverage (over both land and seas) and non-dependency on local/on-site equipment. The main objective of the proposed activity is to study and define a GNSS spectrum monitoring-system, tailored to non-PRS applications, based on space-borne monitors, enabling worldwide detection, characterisation and localisation of GNSS interferers, and enabling a warning for users regarding possible presence of interference. The tasks to be performed will include:

  • constellation dimensioning, including analysis of planned LEO mission opportunities or analysis of dedicated constellations of mini-satellites;
  • space-borne monitor equipment(s) definition and performance analysis;
  • software demonstration of monitor performance in an emulated  environment;
  • study of possible real-time communication channels for warning GNSS users;
  • implementation and development plan.

The main results of the activities will provide feasibility analysis and conceptual design of a system for worldwide detection, warning, characterisation and localisation of GNSS interference.
Coordination with the Interference Monitoring Task Force (EGITF) will be ensured through EC and GSA.