1. A method of estimating a platform position with high accuracy, comprising the following steps of: receiving GPS signals from satellites and processing the GPS signals for producing position estimation information; obtaining image data of landmarks surrounding the platform through a camera mounted on the platform; conducting an image recognition process on the image data thereby extracting attributes and feature characteristics of the landmarks; registering the attributes and feature characteristics of the landmarks in a landmark database thereby establishing and updating the landmark database; and incorporating the attributes and feature characteristics of the landmarks into the position estimation information produced from the GPS signals, thereby improving accuracy of the position estimate.