Method for transfer alignment of an inertial measurement unit in the presence of unknown aircraft measurements delays

A method for velocity match transfer alignment between a carrier vehicle and a carried vehicle comprising of:

• a) repeatedly measuring a velocity difference between the carrier vehicle and the carried vehicle;
• (b) subsequent to each said measurement, updating a state vector that include a predicted value of said velocity difference;
• (c) between said measurements, propagating said state vector forward in time;
• and
• (d) moving the carrier vehicle and the carried vehicle along a trajectory that includes a first segment, a second segment and a third segment, said moving along said first segment being effected at a first substantially constant velocity, said moving along second segment including an acceleration, said moving along said third segment being effected at a second substantially constant velocity different from said first velocity, said measuring, said updating, and said propagating being effected during said moving along said first and third segments, only said propagating being effected while moving along said second segment.