SkyTEM ? a new high-resolution helicopter transient electromagnetic system

Kurt I. Sørense, Esben Auken

Publikation: Bidrag til tidsskriftArtikelForskningpeer review

334 Citationer (Scopus)

Abstrakt

SkyTEM is a time-domain, helicopter electromagnetic system designed for hydrogeophysical and environmental investigation. Developed as a rapid alternative to ground-based, transient electromagnetic measurements, the resolution capabilities are comparable to that of a conventional 40 ´ 40 m2 system. Independent of the helicopter, the entire system is carried as an external sling load. In the present system, the transmitter, mounted on a lightweight wooden lattice frame, is a four-turn 12.5 ´ 12.5 m2 square loop, divided into segments for transmitting a low moment with one turn and a high moment with all four turns. The low moment uses about 30 A with a turn-off time of about 4 ms; the high moment draws approximately 50 A, and has a turn-off time of about 80 ms. The shielded, overdamped, multi-turn receiver loop is rigidly mounted on the side of the transmitter loop. This is essentially a central-loop configuration with a 1.5 m vertical offset. In vertical hover mode the SkyTEM responses were within 2% of those from a conventional ground-based system. Instrument bias level is not a concern as high-altitude tests showed that the background noise level is higher than the instrument bias level. By inverting a sounding from a test site to a standard model and then applying the SkyTEM system parameters to compute the forward response, conventional measurements were within 5% of SkyTEM responses for flight heights of 7.25, 10, and 20 m. Standard field operations include establishment of a repeat base station in the survey area where data are acquired approximately every 1.5 hours, when the helicopter is refuelled, to monitor system stability. Data acquired in a production survey were successful in detecting and delineating a buried-valley structure important in hydrogeophysical investigations.

OriginalsprogEngelsk
Sider (fra-til)194-202
Antal sider9
TidsskriftExploration Geophysics
Vol/bind35
Udgave nummer3
DOI
StatusUdgivet - 2004
Udgivet eksterntJa

Programområde

  • Programområde 2: Vandressourcer

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