Patent ID: 8170796

Claim:
An apparatus, comprising: a first navigation unit associated with a first platform and comprising a first global position system (GPS) sensor configured to provide first GPS position coordinates and a first INS sensor configured to provide first INS position coordinates; a second navigation unit associated with a second platform and comprising a second GPS sensor configured to provide second GPS position coordinates and a second INS sensor configured to provide second INS position coordinates; a position system coupled to the first and second navigation units, configured to determine a GPS change vector from said first GPS position coordinates and said second GPS position coordinates, and an inertial navigation system (INS) change vector from said first INS position coordinates and said second INS position coordinates; wherein the first and second GPS position coordinates and the first and second INS position coordinates indicate a relative position between a first platform and a second platform; and wherein the position system is configured to correct a GPS position calculation error based on the GPS change vector and the INS change vector.