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原文传递 NEW LIFE FOR OLD TRANSMITTERS: CONVERTING GWEN TO NDGPS.

题名：	NEW LIFE FOR OLD TRANSMITTERS: CONVERTING GWEN TO NDGPS.
作者：	Arnold-JA
关键词：	Automobile-navigation-systems; Global-Positioning-System; Ground-Wave-Emergency-Network-GWEN; Ground-transportation; Highway-transportation; Maryland-; Nationwide-Differential-Global-Positioning-System-NDGPS; Navigation-systems; Navigational-satellites; U.S.-Dept.-of-Commerce; U.S.-Dept.-of-Defense; U.S.-Dept.-of-Transportation; United-States; United-States-Air-Force; United-States-Coast-Guard
摘要：	The practical applications of the Nationwide Differential Global Positioning System (NDGPS) are expanding exponentially. This system of 300-ft-high broadcast towers is being created to improve the accuracy of the positioning information obtained via radio signals emitted by the GPS satellites in orbit around the Earth. In 1994, the Departments of Transportation, Commerce, and Defense recommended expanding the Coast Guard's differential GPS system. They also noted that the U.S. Air Force, which operated the Ground Wave Emergency Network (GWEN), planned to decommission the network and its national network of 53 transmitters. In a later field test, it was demonstrated that these transmitters could be successfully used to provide navigational information for surface transportation applications. This article discusses the conversion of existing GWEN sites to NDGPS sites, focusing on 2 sites in Annapolis and Hagerstown, Maryland.
总页数：	Public Roads. 2001/09. 65(2) pp28-29 (2 Phot.)
报告类型：	科技报告