Prince Charles Mountains Expedition of Germany-Australia (PCMEGA)

Full description

These data are gravity and magnetometer data collected as part of the PCMEGA (Prince Charles Mountains Expedition of Germany and Australia) expedition of 2002/2003.

An excerpt from the readme file associated with the data are provided below. For the full information, see the download file.

************************************************************************
* PCMEGA Airborne Magnetics and Gravity Survey *
* Prince Charles Mountains, Australian Territory, Antarctica *
************************************************************************
------------------------------------------------------------------------
SURVEY SPECIFICATIONS
------------------------------------------------------------------------
Survey company Fugro Airborne Surveys / Fugro-LCT
FAS job number 1550
LCT job number 5203
Survey dates December 2002 - January 2003
Base of operations Mount Cresswell, Antarctica

Traverse spacing 5000 metres
Traverse direction 000-180 degrees
Tie spacing 25000 metres
Tie direction 090-270 degrees
Line kilometres flown 29,844

Survey altitude constant GPS height
Mean GPS Height
Area X2138 metres
Area Y2745 metres
Area Z3347 metres

Survey boundary
Datum WGS84
1. 67.799202E 77.581104S
2. 61.088149E 77.189071S
3. 62.633286E 75.420516S
4. 60.171411E 75.219142S
5. 61.877412E 73.837674S
6. 66.818626E 74.203749S
7. 67.469672E 73.373793S
8. 70.743586E 73.546207S
9. 67.799202E 77.581104S

------------------------------------------------------------------------
GEODETIC INFORMATION
------------------------------------------------------------------------
Datum WGS84
Projection Lambert Conic Conformal
Central meridian 80E
Latitude origin 75S
False easting 928916
False northing 554262
Standard parallel 1 72.66667S
Standard parallel 2 75.33333S

------------------------------------------------------------------------
AIRCRAFT
------------------------------------------------------------------------
Aircraft type DHC-6-300 Twin Otter
Aircraft registration C-GCKB
Aircraft supplier Kenn Borek Air Canada
Average velocity 67 metres/second

------------------------------------------------------------------------
MAGNETICS SYSTEM
------------------------------------------------------------------------
Magnetometer Scintrex Model CS-2 Caesium Vapour
Installation bird towed on 53 metre cable
Resolution 0.001 nanotesla
Cycle rate 0.1 second
Sample interval 6.7 metres

Base station 2 x Scintrex Envi Mags
Cycle rate5 seconds

------------------------------------------------------------------------
GRAVITY SYSTEM
------------------------------------------------------------------------
Gravity system LaCoste and Romberg 'S' Meter
ZLS UltraSys Airborne upgraded
Resolution 0.1 mGal
Cycle rate 1 second
Sample interval 67 metres

------------------------------------------------------------------------
ALTITUDE SYSTEM
------------------------------------------------------------------------
Radar altimeter Collins ALT 50 Radar Altimeter
Range approximately 750 metres
Cycle rate 0.1 second

Laser altimeter Optech ADM Laser Altimeter
Range approximately 600 metres
Cycle rate 0.1 second

Barometric altimeter Paroscientific 215A-101

------------------------------------------------------------------------
POSITIONING SYSTEM
------------------------------------------------------------------------
Aircraft GPS Trimble 4700
Navigation system Picodas PNAV-2100
Navigation real-time differential GPS
Base GPS Novatel GPScard 951R
Flightpath recovery post-processed differentially corrected GPS

========================================================================

Lineage

Progress Code: completed

Statement: See the readme file in the download directory for full details on methodology used and descriptions of these data. The strain-grids were surveyed using Leica series 399 dual-frequency GPS receivers. The stop-and-go technique was chosen for this work as it provides a very efficient and relatively robust method for surveying large numbers of points in areas with good horizon visibility. The technique combines dual-frequency carrier phase data from a fixed receiver with those recorded by a roving receiver occupying discrete points (in this case the strain-grid markers). In the field reference receivers were set-up locally on the glacier surface for each survey due to the lack of nearby rock outcrop. Coordinates for the reference receivers were later computed using the AUSPOS online GPS processing service maintained by Geoscience Australia. AUSPOS imports raw data submitted via the internet and processes it differentially against a network of nearby permanent GPS sites in Antarctica (e.g. at Casey, Davis and Mawson). The AUSPOS derived coordinates were then used to provide fixed reference for the ensuing survey network adjustments (using least-squares) incorporating the stop-and-go baselines. This was accomplished by post-processing of the data using commercial GPS processing software. The relative precisions of the stop-and-go baselines are typically at the centimetre to sub-centimetre level (as shown in the spreadsheets). The absolute accuracies of the coordinates, however, would not be better than +/- 2cm in horizontal and +/- 5cm in vertical, accounting for the small accumulated errors of the fixed reference station that arise from: (i) precision of the AUSPOS output, and; (ii) centimetre to sub-centimetre movements of the reference station, on the slow-moving glacier platform, during the survey periods.