Distributed Seismic Navigation System
Multiple Sources
Eider communicates with the energy source synchronizer to allow for multiple source
operation, gun data is collected at each shotpoint as mentioned above to confirm the
source fired.
On multi vessel crews, the header data sent over the Eider radio link is displayed on the
recorder, allowing for real-time observation of the integrity of the energy source. Data
out of spec based upon operator defined inputs are logged to an error file on the Eider QC
computer and out of spec events are marked with a traffic light display.
Muli-Vessel Synchronization
The energy source and recording instruments are synchronized using GPS clocks to
ensure time-break is received on both vessels at the same time. Confirmation of the
events is transmitted back to the source vessel and logged to the header in Eider for
transmission to the recorder. Multiplexing of the data transmissions is also a function of
the Eider package.
SPS Files
Eider QC generates the real-time SPS S-Files for use in binning and first break picking
algorithms. SPS R-files are generated from the UKOOA P1/90 processed files from the
cable vessels. Relational files are received from the recorder.
Post Processing
Realtime data is logged into the NaviPac database. These data are available for postprocessing
using NaviEdit which provides the following data processing tools;
- Smoothing of noise
- Spike rejection
- Data interpolation
The raw data integrity is preserved in the data-base to allow for reprocessing and more importantly recovery of the
data should it become “overprocessed”
Once the individual data sets are refined to the operator’s satisfaction, the data is used to generate the group locations based upon the vessel positions, cable shape and offset information.
P1/90
Once the data is processed to the operator’s satisfaction the complete data set is used to
export the UKOOA P1/90 processed data set.
QC
SPS file maintenance and QC is performed using the FGPS SPS-Pro utility optionally
provided with the Eider / NaviPac package.
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