Constraining navigational drift in a munition

Abstract

A method and system for constraining navigational drift in a munition caused by Inertial Measurement Unit (IMU) bias error during flight of the munition in a constellation of a plurality of munitions in a Global Positioning System (GPS) denied attack. Each munition is provided with a datalink communication system to communicate with other munitions in the constellation and a navigation system having an IMU for guiding the munition in flight. An estimated position and covariance of the estimated position is determined for each munition via each munitions' navigation system. A range of each munition relative to at least one other munition in the munition constellation is determined via each munitions' datalink communication system. The estimated position and range to at least one other munition in the munition constellation is shared by each munition via each munitions' datalink communication system. Navigational drift for each munition is determined utilizing the estimated position of at least one other munition and the range to that at least one other munition in the munition constellation. And navigational drift in each munition is constrained by compensating for IMU bias error in each munition utilizing the determined navigational drift for each respective munition in the munition constellation.