Utilization of a magnetic sensor to compensate a MEMS-IMU/GPS and de-spin strapdown on rolling missiles

A method for computationally de-spinning strapdown inertial sensor measurements for navigation on a rolling vehicle, comprising:

• sampling navigation data of a rolling vehicle, the sampled data including accelerometer data, roll data, pitch data and yaw data for the rolling vehicle;
• integrating roll data of the sampled data over a predetermined interval;
• computing a roll angle change transform;
• updating the roll angle change transform with incremental roll change data;
• transforming and integrating accelerometer data with the roll angle change transform whereby the accelerometer data is de-spun;
• transforming and integrating pitch and yaw data with the roll angle change transform whereby the pitch and yaw data are de-spun;
• and
• computing a navigation solution strapdown at a predetermined navigation processing rate.

A method for computing a navigation solution in a rolling vehicle, comprising:

• sampling navigation data of a rolling vehicle, the sampled data including accelerometer data, roll data, pitch data and yaw data for the rolling vehicle;
• calculating a measurement residual based upon the output of a magnetic sensor that detects the orientation of the rolling vehicle with respect to a local magnetic field;
• updating an inertial attitude error estimate with the calculated measurement residual whereby the navigation solution remains stable;
• computationally de-spinning accelerometer and pitch and yaw data;
• and
• computing a navigation solution strapdown at a predetermined navigation processing rate with the de-spun accelerometer, pitch and yaw data.