The resolution increasing problems are discussed for airborne electromagnetic survey. It is a key issue for searching small isometric in plan objects, like kimberlite pipes. The theoretical possibility of survey with 50 m distance between lines is shown. Necessary practical requirements are declared for such scale. They are a solution of navigational task, transmitter positioning with respect to receiver and with respect to the ground, system’s geometry limitations. Future trends are analyzed on acquired data for detailed surveying on adjacent territories of ex- ploited or duffer deposits.
Since May 2011 we have collected long-period magnetotelluric (MT) data in non-magnetic pavilion on geophysical base of Moscow University in Kaluga region. Three sets of electrical lines with different types of electrodes were installed. Different groups of authors have made processing of MT records, calculation of apparent resistivity curves. These curves were compared with apparent resistivity curve obtained on magnetovariational data of Moscow observatory. The 1D inverse problem was solved for the deep part of the generalized curve (T > 30 s). In particular we succeeded in finding preliminary conductivity values on the depth of crust, upper and middle mantle.
Each year there is a great volume of airborne electromagnetics in Russia, estimated hundred thousand linear kilometers. Among the equipment involved in this survey, the greatest share is occupied by system, developed by «Geotechnologies» JS. Changing position between receiver and transmitter leads to changing of induced field parameters in receiver axes by value much higher than amplitude of the useful signal. Until recently, due to this circumstance, it was impossible to use inphase component of the response in data interpretation. Institute of Control Sciences together with «Geotechnologies» JS has developed algorithms that allow to detemine relative positioning of the receiver axes with respect to inducing moment vector. It has allowed passing without accuracy loss from polarization ellipse invariants to components of the reflected field. Their usage led to a new quality level of interpretation.
Geophysical methods, particularly electromagnetic methods, have been very successfully applied for purpose economic base metal and precious metal ore bodies discovering. Airborne electromagnetics is one of electroprospecting methods. There are several types of airborne electromagnetics variants. All of them measure magnetic part of the electromagnetic field. The achieved goal of the native instrument-making industry is helicopter-borne time-domain electromagnetic «Equator» system. Having practically the same quality of the data, the system favorably differs from analogues on prime-cost surveying.