Integrity Monitoring and Augmentation

An integrity monitoring solution uses GNSS signals to detect changes or anomalies in satellite signal characteristics that could affect the accuracy of the position calculated by the user equipment. Integrity monitoring is essential to any application that relies on GNSS measurements, particularly for those for which misleading, undetected errors could affect safety of life. A pplications include:


Civil Aircraft Landing Systems

The use of GNSS technology in civil aircraft landing systems presents an excellent example. Integrity monitoring networks consisting of fixed ground reference stations are frequently set up to continuously measure GNSS signal characteristics.

Slight changes in the signals can be tolerated by sending correction information to the receiver on board an aircraft. If certain integrity limits are exceeded, the system will notify the user equipment within seconds so that the affected satellite is excluded from the user's position calculation.

Satellite-Based Augmentation Systems (SBAS)

Augmentation systems provide additional data to users of GNSS equipment to improve accuracy, reliability and availability. The United States' WAAS, the European EGNOS and the Japanese QZSS, are examples of SBAS.

Integrity and correction data is generated based on measurements from a ground network and transmitted to geostationary satellites (GEO's), which then relay the information to the GNSS users. By using the same frequencies, modulation and signal structure as the GNSS signals, the SBAS GEO is able to provide information to the user's receiver(s) via one of the GNSS receiver channels.


  • Detects changes or anomalies in GNSS signals
  • Enhances the accuracy of GNSS systems by providing integrity and correction data
  • System integrity is increased by having ability to trust the system within certain accuracy limits
  • Improves position accuracy with correction data transmitted from SBAS systems
  • Enhances GNSS measurement availability and continuity of service by using the SBAS system signals themselves for additional GNSS range measurements