1. A method of estimating the position of a ground vehicle during travel along a route, comprising: storing in a database, a set of landmarks and landmark location coordinates for each landmark; initializing position with known location coordinates; receiving current yaw rate (W) and vehicle speed data (v); using visual perception equipment to identify landmarks; when no landmark is identified, using the following calculations or other forms of state estimation to estimate the vehicle's current position data: 
 y est =∫v cos( H est ) dt 
 x est =∫v sin( H est ) dt 
 H est =∫{dot over (ψ)}dt when a landmark is identified, using the following calculations or other forms of state adjustment to determine vehicle location data: 
 y est =y landmark +y offset 
 x est =x landmark +x offset 
 H est =θ landmark +θ offset using the landmark location coordinates to correct the current position data.