Calibrating a tightly-coupled GNSS/MU integration filter
AssigneeTexas Instruments Incorporated
InventorJune Chul Roh
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Abstract
Embodiments of the invention provide methods of calibrating a blending filter based on extended Kalman filter (EKF), which optimally integrates the IMU navigation data with all other satellite measurements (tightly-coupled integration filter). In one embodiment a coordinate transformation matrix using a latest position fix is created. The state variables (for user velocity) are transformed to a local navigation coordinate. The state variables of said integration filter is estimated. A blended calibrated position fix is the output of the method.
Claims7
A method of calibrating a hardware integration filter of a global navigation satellite system (GNSS) receiver, said method comprising:
- creating a coordinate transformation matrix using a latest position fix;
- transforming a plurality of state variables for an inertial navigation system (INS) user velocity to a local navigation coordinate using said coordinate transformation matrix;
- including a plurality of inertial navigation system (INS) measurements in said local navigation coordinate in a measurement equation in a way that said INS measurements are a function of a plurality of velocity variables and speed bias and heading bias variables of a state of the integration filter with a plurality of measurement noises;
- and
- estimating said plurality of state variables including speed bias and heading bias of said integration filter.
Dependencies are inferred from the claim text.