Laptop Automated Navigation Aid Positioning System with Differential GPS

Abstract

The advent of the Global Positioning System (GPS) brought about changes in positioning and surveying that are only now being fully exploited. When GPS is in place, positioning accuracy of 100 m or less will be available worldwide, 24 hr/day, in all weather and visibility conditions. The Coast Guard grasped the significance of the potential of the GPS system and has developed a system to improve the accuracy of GPS from 100 m to 5–10 m; this is the differential GPS system, or DGPS. The Short Range Aids to Navigation Division recognized the potential use of DGPS as a new tool for aid positioning. Our present manual buoy‐positioning methods are tedious, time‐consuming, and error‐prone. For these reasons our units must continually check and recheck their positions with electronic navigation aids, radar information, and horizontal sextant angles to place a buoy on station. Automation of this procedure with DGPS input would allow units to obtain real‐time positioning information for navigation and aid placement. The Coast Guard Research & Development Center was tasked with developing an automated navigation aid positioning system. Their efforts provided us with the Laptop Automated Aid Positioning System, or LAAPS. For the Short Range Aids to Navigation Division, LAAPS is everything it was expected to be. The USCGC Bittersweet, out of Woods Hole, Mass., is testing the system and is finding it can find the position of aids to navigation with 2–3 m accuracy. Plans call for nationwide coverage of DGPS by 1996. By that time all Coast Guard aids‐to‐navigation units will have LAAPS ready for operation.