Method and assembly for monitoring the integrity of free inertial position and velocity measurements of an aircraft

An inertial measurement assembly of an aircraft with integrated integrity monitoring, comprising:

• a single high-grade measurement unit;
• and
• at least two low-grade measurement units;
• wherein the single high-grade measurement unit is of a inertial navigation system (INS) type and the at least two low-grade measurement units are of an attitude heading reference system (AHRS) type,
• wherein each of the measurement units comprises a sensor unit and a processing unit operatively coupled to the respective sensor unit,
• wherein the respective sensor units are configured to measure accelerations and angular rates of the aircraft and provide raw data based on said measurement;
• wherein the respective processing units are configured to process the raw data provided by the sensor units and provide processed data reflecting the velocity and/or attitude of the aircraft;
• the assembly further comprising:
• a sensor monitoring unit configured to receive the raw data output by each of the sensor units and evaluate according to at least one predetermined criterion whether the raw data of each sensor units are consistent with one another;
• an attitude monitoring unit configured to receive the processed data output by each of the processing units and evaluate according to at least one predetermined criterion whether the processed data of each processing unit are consistent with one another.