Patent ID: 7957898

Claim:
A method of updating three dimensional tracking of a platform by a micro-electro mechanical systems (MEMS) based INS, comprising the following steps of: numerically integrating Northerly, Easterly, and downward velocities to track Northerly, Easterly, and vertical displacement from a reference point along a local tangent plane about the reference point; converting latitude and longitude into Northerly and Easterly displacement from the reference point using the Earth North-South and East-West curvatures computed for the reference point; ignoring the Earth rotation and the rotation of the local tangent plane with respect to Earth since they are much smaller than MEMS gyro noise and bias; and assuming the platform orientation conditions of: −90 (deg)<pitch<90 (deg) −90 (deg)<roll<90 (deg) to reduce the number of parameters rectuired to track in a direction cosine matrix.