4Xia M Y,Chen Z Y.Attenuation predictions at extremely low frequencies for measurement-while-drilling electromagnetic telemetry system[J].IEEE Transactions on Geoscience and Remote Sensing,1993,31(6):1222-1228.
5Wolf S A,Davis J R,Nisenoff M.Superconducting extremely low frequency(ELF)magnetic field sensors for submarine communications[J].IEEE Transactions on Communications,1974,22(4):549-554.
6Rowe H E.Extremely low frequency communication to submarines[J].IEEE Transactions on Communications,1974,22(4):371-385.
7da Silva J A P,de Castro Antunes R,Afonso O J R,et al.A smart location system[C]//2004 International Pipeline Conference.Calgary,Alberta,Canada:American Society of Mechanical Engineers,2004:975-981.
8QI Haiming,YE Jinrui,ZHANG Xiaohua,et al.Wireless tracking and locating system for in-pipe robot[J].Sensors and Acutators A:Physical,2010,159(1):117-125.
9QI Haiming,ZHANG Xiaohua,CHEN Hongjun,et al.Tracing and localization system for pipeline robot[J].Mechatronics,2009,1:76-84.
