ESA's Navigation Experts

The Navigation Support Office contributes to a broad spectrum of European Space Agency missions and programmes. Read on to learn more, check out our Past Successes, or take a look at one of our in-depth articles on GOCE, ESTRACK Ground Stations, or Sentinel POD.

European GNSS programmes

The Navigation Support Office supports the European GNSS programmes, EGNOS and Galileo. Key activities include ground station deployment and the monitoring of station, satellite and product performance. In addition:

  • leadership of the GGSP consortium, including the generation of the system-critical Galileo Terrestrial Reference Frame

  • support to the deployment of the EGNOS Ranging Integrity Monitoring Stations (RIMS)

  • support to the deployment of the experimental and operational Galileo Sensor Stations (GESS and GSS)

  • routine generation of precise Galileo orbits for laser ranging of Galileo satellite, coordinated by the ILRS

  • engineering support for troubleshooting, product improvement, and system maintenance

Earth Observation Missions

The Navigation Support Office is a leading institution for the precise orbit determination of LEO satellites. Currently, the Office is playing a key role in the precise orbit determination for the Sentinel spacecraft, building on a legacy of operational orbit support to ERS, Envisat, and CryoSat-2. Solutions with multiple simultaneous data types (GNSS, SLR, DORIS, altimetry, S-band range, Doppler, and angle tracking) are typically performed, allowing the alignment of different reference frames and estimation of inter-system and instrument biases.

Of particular note are the ESA gravimetry mission GOCE and the NASA altimetry missions Jason-1 and -2. Centimetre-level orbits, particularly in the vertical direction are critical to the success of these missions. The Navigation Support Office supported instrument calibration, analysed and improved of physical models


ESA's Space Tracking Network, ESTRACK , is a global system of ground stations providing links between satellites in orbit and ESOC. Highly accurate ground antenna positions are required for precise orbit determination. The Navigation Support Office has developed and maintains a dedicated directory, the ESA Tracking Site Directory (ESA TSD), which provides the antenna positions in the latest International Terrestrial Reference Frame (ITRF).

In addition to the provision of the antenna positions, the local geodetic networks at the various sites are documented in the ESA TSD. In the case of the installation of new antennae or constructional alterations, this will enable the determination of antenna positions by use of the existing geodetic network.

Learn more in our in-depth article...

Space Situational Awareness (SSA)

An important atmospheric application of GNSS data is the monitoring of ionospheric activity (total electron content or TEC), which can seriously disturb satellite communications. Dual-frequency GNSS signals enable direct measurement of ionospheric activity. By merging the data from hundreds of globally distributed GPS receivers, detailed maps of the TEC and its evolution as a function of time can be constructed. The Navigation Support Office provides ionospheric TEC maps to the scientific community.