Frank Klucznik Kristi McRacken John Killers Jason Judy U.S. Coast Guard, Differential GPS, Nationwide Control Station. 210 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2959&spage=210 2004 conf/iccbss/2004 ICCBSS db/conf/iccbss/iccbss2004.html#KlucznikMKJ04