Wessex Archaeology (WSX) Geophysical Survey WESSEX1: (11/Jun/2003 to 26/Jun/2003)

Geophysical equipment types used included: Magnetometer and Surface Tow Boomer. Emu Ltd was contracted to undertake the survey on behalf of Wessex Archaeology. The multibeam service provider Netsurvey Ltd. was commissioned to setup and carry out the multibeam sonar survey. The echosounder system used was a Reson SeaBat 8125 multibeam echosounder system with 240 dynamically focussed 0.5º beams, a swath coverage of 120º and a reported depth resolution of 6mm. Components of the system comprised the sonar head itself, a sonar processor unit, sound velocity probes and a dual processor PC with increased hard disk capacity running Reson 6042 acquisition and survey software. The vessel movement was compensated for with an Applanix POS MV (Position Orientation System for Marine Vessels), utilising two Novatel GPS antennas mounted on the A frame of the vessel at the stern to deliver heading and motion information, a gyrocompass for heading information, and a motion reference unit to correct heave, pitch and roll. Positioning was provided by a LEICA SR530 24-channel dual-frequency survey receiver with on-board RTK. A GSM (Global System for Mobile communications) compatible mobile phone was used to receive differential corrections from a base station placed at surveyed locations ashore. The archived data is post-processed. Processing included cleaning of the data to remove bad points and application of tidal parameters. A Geometrics G-881 caesium vapour magnetometer was used for the magnetometer survey and the data were recorded in Maglog software. This was then exported as *.txt format files. Layback positions have been applied to the data and do not need to be added during processing. For the sub-bottom profiler survey an Applied Acoustics AA200 boomer plate was used mounted on a CAT200 catamaran. The AA Capacitor Charging Unit CSP1500 provided the energy for the boomer plate. An Octopus 360 recording unit received all data from the hydrophone and annotated positioning information in the form of fixes every 10 m along the line rather than a unique position for each sounding. Data for archive includes tiff images of the boomer data lines and an associated navigation text file with position for each fix with all offset and layback data applied.

Minimal Distance: 5 urn:ogc:def:uom:EPSG::9001

INSPIRE Implementing rules laying down technical arrangements for the interoperability and harmonisation of unknown theme