With over 2,500,000 lkm of survey data collected in 41 countries particularly on the African continent and Middle East, the Xplorer™ system sets the industry standard for high resolution helicopter-borne magnetic and radiometric survey.



XPlorer™ gradiometer systems utilise dedicated low-noise aircraft, non-magnetic composite horizontal-boom mountings, high speed synchronous data sampling and gradient sensor configurations.

Employing dedicated powerful ASTAR B-series helicopters as a platform, XPlorer™ systems are able to maintain a tight drape with low survey height essential for collecting quality high resolution data. The Xplorer™ system has proven robust and delivered consistently.


Aeromagnetic data is used routinely in most exploration environments to provide essential lithological and structural mapping. Mineralisation is often hosted in complex geological environments and projects benefit significantly from collection of high resolution magnetic data. As magnetic anomalies decay exponentially with distance from source, low survey height is a key component to data quality and encourages the use of helicopter platforms which are also ideal in environments with rugged topography.

Low survey height results in a dramatic improvement in high frequency content:

  • More structural and textural information
  • Better gradient enhancement
  • Improved anomaly definition

Gradient enhanced products improve:

  • Spatial positioning of anomalies
  • Resolution of line parallel features
  • Overall resolution – equivalent to flying at tighter line spacing

High speed data sampling of magnetic (20 Hz) and DGPS (10 Hz) data improves:

  • Definition of short-wavelength anomalies


Aerial gamma-ray surveying reflects geochemical variations of potassium, uranium and thorium in the upper 30 cm of the Earth’s surface. Radiometric surveying thus provides a powerful and cost effective means of mapping outcropping and subcropping geology. In addition to basic lithological information, radiometric data is used directly to map alteration zones (e.g. porphyry copper and shear zone hosted gold); identify surficial extent of uranium mineralisation; and prioritise and discriminate Fe-oxide-Cu-Au, granophile deposits and mafic targets.

Legislation requiring radiation pollution monitoring for the mining industry is becoming a standard in many countries. This is an ideal application for ultra-high resolution radiometric survey.

As part of the XPlorer™ package, NRG™ offers high resolution, full-spectrum radiometric data as a complement to its industry-leading gradient enhanced magnetic data. The reduced survey height offered by a helicopter platform significantly improves signal to noise ratio; which in turn enables a higher sampling rate of 2 Hz (which can be further increased for ultra-high resolution survey). This, coupled with slower survey speed, results in a down-line sample window of approximately 20 m which is a three-fold improvement on standard fixed-wing systems. Up to 2048 in³ NaI crystal pack is employed with full spectrum recorded using industry-leading Radiation Solutions spectrometers. Full spectral NASVD processing is applied to all data as a standard.


Custom designed and built, the NRG™ data acquisition system is at the core of the XPlorer™ system. Synchronous, high speed sampling (> 1,000 Hz) is controlled using a Rb atomic clock. The high sample rates allow for intelligent down-sampling of magnetic data to a 20 Hz base frequency which results in an extremely low noise envelope. Similarly, sample rates of ancillary and GPS data are increased. Flight steering and real-time QC is achieved through a GUI interface for safe pilot-only operation.



Magnetic Gradiometer Platform
TypeHorizontal Gradient
Sensor Separation13m
Typical Gradient Noise envelope0.001nT/m SDEV 4th diff
Aircraft TypeAS350B Series
Engine TypeTurbine
Fuel TypeJetA1
Acquisition System
CPUDual Core ARM 1.5Ghz
Operation Temperature-10 to 65 Degrees C
Standard Sampling Rate20 Hz (capable of >1kHz)
Magnetometer Counter
Internal System Noise<0.0001 nT
Adc Inputs24
Magnetometer Inputs4
Recording Rate20 Hz (capable of >1kHz)
Magnetometer Sensor
TypeScintrex CS3
Measurement Range15 000 – 105 000 nT
Gradient Tolerance40 000 nT/m
Operating Temperature-40 to +50 Degrees C
Recording Rate20 Hz (capable of >1kHz)
Fluxgate Magnetometer
Analogue output+- 10 V
Linearity error<0.0015%
Calibration accuracy+- 0.5%
Bandwidth0.3 KHz
Internal noise<6 pTrms/Hz @1Hz
Recording Rate20 Hz (capable of >1kHz)
Base Station Magnetometer
ManufacturerNRG Engineering
Range15 000 to 105 000nT
Sensitivity0.0006 nT vHz RMS
Recording Rate1Hz
GPS Positioning
TypeNovatel DL-V3L1L2
Differential CorrectionReal Time
Code TrackedC/A
Number of Satellites12
Recording Rate20 Hz
Gamma-Ray Spectrometer
TypeRadiation Solutions – RSX4
Spectral AnalysisReal Time
Data Recorded256 channel full spectrum
Measurement Range0 – 3.0 MeV
Dead TimeZero
Recording Rate2 Hz
Energy Resolution<8.5%
Radiometric Detector
TypeSodium Iodide
Volume16.7 litres
Recording Rate2 Hz
Pressure Resolution0.001 mb
Operating Pressure Range600 – 1060 mb
Recording Rate20 Hz (capable of >1kHz)
Resolution0.05 DegC
Accuracy0.1 DegC
Recording Rate20 Hz (capable of >1kHz)
Radar Altimeter
TypeFree Flight
Operating range0 – 762 m
Accuracy 0 – 10 m+-0.3m
Accuracy 10 – 762 m+-0.5m
Recording Rate20 Hz (capable of >1kHz)
Laser Altimeter
Range0 – 60 m
Recording Rate20 Hz (capable of >1kHz)
Field Data Verification System
Processing Software PlatformsGeosoft Oasis Montaj and Proprietary Software

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