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With our head office in Brisbane and field office in Santiago, Chile GRS are capable of worldwide exploration

Areas We Cover

SET-UP

Up to 300 Channels (60 – 80 more common)

Receiver Data Acquisition Unit (DAU) with battery connected by LAN cable. Receiver sensor is a steel plate

Central Recording/Transmitting location

MT Acquired on same array with the addition of magnetometers (BF-4’s) and Ey dipoles into network

MT used as standalone dataset, QC of DC resistivity, joint DC/MT inversion and for Telluric Cancellation (TC)

True remote location >20km away

SYSTEM LAYOUT

LAN - therefore dipole - length can be as needed (previous discussion required) eg 50m, 100m, 200m

LAN cables may be added together to cover greater distances (eg. From Dogbox to line for hard to get to locations or across grids with line separation >200m)

Receiver and transmitter locations may be anywhere (eg. If line cannot be straight because of infrastructure, heritage zones etc)

Layout may be 2D or 3D depending on client requirements

Entire grid set out and recorded at once resulting in both PDP and DPP

DATA ACQUISITION

Full time series TX I and RX V recording

Data acquired and viewed on site allowing real-time QC.  Acquisition software is QC software.

Transmit points generally midway between receivers removing any risk of damage to equipment resulting in non-integer n-values (0.5, 1.5, 2.5 etc)

Because arrays are laid out in full pseudosections are a triangle down to whatever n-value present.

PROCESSING

1.   Time series collection of transmitted and received 100% duty cycle signals.

2.   Conversion of raw time-series into real units using calibrations for sensors and individual DAUs optionally with the removal of tellurics through the recording and calculation of an Inferred Natural Field (Rowston et al. 2003).

3.   Ensemble stacking of transmitted and received time series, perfectly rejecting linear drift, whilst minimising noise outside of the transmitter fundamental and harmonics.

4.  Conversion of stacked data to the frequency domain.

PROCESSING

5.  Calculation of the system response for individual stacks.

6.  Optional automatic selective rejection of outlier system response stacks.

7.   Averaging of system response stacks, weighted by observational errors.

8.   Convolution of the system response with a 50% duty cycle frequency response at the fundamental period.

9.   Conversion back to time domain for operator QC display.

ADVANTAGES

Telluric Cancellation generally increasing S:N by a factor of 5 creating repeatability to the microvolt level

Full time series TX I and RX V recording with real-time QC permitting frequency domain transformation and input into MARE2DEM allowing joint CSEM/MT inversions

True 3D data collection and inversion

Calibration and sensor testing to minimize noise at receivers

Data immediately available to clients in industry standard formats