Airborne gravimetry · strapdown design

AGP-GRAV

Mobile strapdown gravimeter for measuring the gravity field from a moving base.

Hardware and software system based on a navigation-grade strapdown inertial system, without a gyrostabilised platform. Error in gravity-anomaly measurement: <0.2 mGal.

Instrument configuration

< 0.2 mGalerror

±2 gdynamic range

320 Hzrecording rate

Request a quotation Specifications

Tests

Comparison with the GT-2A platform gravimeter

The instrument has been tested on aircraft, helicopters and marine vessels. The programme included comparison with the GT-2A platform airborne gravimeter and repeat measurements along a single line. The field data and processing results were independently reviewed by the Institute of Physics of the Earth RAS, the Faculty of Mechanics and Mathematics of Moscow State University and VNIGNI.

Design

Strapdown inertial system

The strapdown design operates without a stabilised platform.

Without a gyrostabiliserThe strapdown design does not use a gyrostabiliser.

Six accelerometersThe instrument includes 6 navigation-grade accelerometers.

Three gyroscopes3 navigation-grade gyroscopes — orientation without a gyrostabiliser.

Two sets2 independent sensor sets — measurement redundancy.

Navigation-grade GNSSGNSS provides positioning and navigation within the system.

Less than 120 WInstrument power consumption: < 120 W.

Specifications

AGP-GRAV specifications.

AGP-GRAVspecifications
Parameter	Value
power consumption	< 120 W
weight	25 kg
dynamic range	±2 g
number of gyroscopes	3
number of accelerometers	6
gravity anomaly error	< 0.2 mGal
recording of all sensor measurements	up to 320 Hz

Tasks addressed

Eight classes of geological tasks

Airborne gravimetry is used to study geological structure and to search for mineral deposits using gravity anomalies.

Fault mappingBlocks and faults from gravity anomalies.

Detection of intrusive bodiesDensity inhomogeneities of intrusions in plan view.

Sedimentary basinsMapping of sedimentary basin structures.

Salt dome tectonicsIdentification of salt domes and density bodies.

Basement structureStudy of the basement from the gravity field.

Geoid modelRefinement of the geoid model.

Oil and gas explorationOil and gas exploration over structures.

Solid mineral explorationExploration for solid minerals.

Carriers

Aircraft, helicopter, vessel

The instrument has been tested on An-2, An-3T and Cessna 208 aircraft, Mi-8 and AS350 helicopters, and marine vessels. Marine tests included operation under ship motion and dynamic loads.

Integration of methods

Combined use of geophysical methods

The ability to operate in close terrain-following mode allows airborne gravimetry to be acquired simultaneously with airborne magnetic, EM and gamma-ray spectrometry surveys, giving data sets consistent in spatial resolution. In Yakutia, four fields over one area were acquired with a single system: the anomalous magnetic field, resistivity at a depth of 100 m, Bouguer gravity and gamma-ray dose rate.

Materials