The GT gravity technology was designed by award winning engineers in Moscow in partnership with CMG. The GT-2A is based on 7 years of operational experience with the GT-1A which brings proven design and fully automatic operation to mobile scalar gravity measurement.
The very large dynamic range provides high precision data even in turbulent flying conditions; data is acquired through short periods of saturation in extreme turbulence by the automatic application of a reduced order Kalman filter, enabling platform misalignment to be computed and hence controlled; the automatic calibration program computes accelerometer scale factors and errors in perpendicularity between the accelerometer sensitive axis and the platform surface. The GT-2A installation in a fixed wing aircraft is shown in Fig 1 (courtesy of Excalibur).
The GT-2A is hermetically sealed for protection when operating in environmental extremes. Short lead-ins improve survey efficiency and reduce costs. Filters depend on aircraft speed and flight conditions and provide spatial resolution typically ranging from 1.2 kms to 3.5 kms.
Fig 2 Repeat lines flown with the GT-2A in Nov 2008 in Ontario, Canada with RMS accuracy = 0.5 mGals.
Specifications | ||
Parameter | Value | Units |
---|---|---|
Measurement range | 9.75 to 9.85 | m/sec |
Dynamic range | +/- 1,000 | Gal |
Static repeatability | +/- 0.3 | mGal |
Resolution | 0.02 | mGal |
Drift per day (corrected) | < 0.1 | mGal |
Roll Limit | +/- 45 | degree |
Pitch limit | +/- 45 | degree |
Operating temp | +10 to +50 | degree C |
Power | 150 at 27Vdc | Watt |
Weight (without rotation table) | 134.5 | kg |
Dimensions (without rotation table) | 400 x 400 x 600 h | mm |