A portable attitude determination apparatus and method are disclosed that can be used with a ship docking system. At least two receivers on a vessel receive Global Positioning System (GPS) satellite data. GPS carrier phase measurements are used to determine attitude (i.e., roll, pitch and yaw angles)...http://www.google.com.au/patents/US5933110?utm_source=gb-gplus-sharePatent US5933110 - Vessel attitude determination system and method
