The arrangement...http://www.google.com/patents/US5914602?utm_source=gb-gplus-sharePatent US5914602 - System including an arrangement for tracking the positional relationship between a boring tool and one or more buried lines and methodAdvanced Patent SearchPublication numberUS5914602 APublication typeGrantApplication numberUS 09/082,142Publication dateJun 22, 1999Filing dateMay 20, 1998Priority d