Device for estimating fuel mass flow rate

The device has a mass flow meter to measure mass flow of a fuel, and a prediction module (26) to find estimated values including estimated metering position and mass flow. Residue calculators (20, 22) calculate residue between measured and estimated fuel mass flows, and residue between measured and estimated metering positions. A module (24) detects corrections to be applied on state variables based on the residues. The state variables comprise real mass flow and parametric uncertainties. An independent claim is also included for a method of determining fluid mass flow measurement for a combustion chamber.