Postplot Errors - Source Table

Operation	Detection Stages	Output	Affected Seismic Operations	Common Errors	Detection Software
Conventional Surveying	Procedural, layout	Vector	Land receiver layout, land source layout (mostly shothole).	Various observational errors, especially large random and gross errors.	Position.exe (closures and cross checks).
Static Carrier Phase GNSS	Processing	Vector	Control networks.	Antenna heights, centring and network design (insufficient independent or non-trivial baselines).	Baseline processing and least squares adjustment software (RMS, integer biases and residuals).
Differential GNSS (DGPS)	Procedural, layout, processing	Point	Rarely used now for vibrator real-time positioning	Loss of correction or satellite signals. Antenna heights.	Position.exe (VAPS or similar files will show bad DOPS or lost corrections).
Kinematic GNSS	Procedural, layout, processing	Vector	Obsolete - receiver and source layout	Initialisation errors and loss of satellite signal. Antenna heights.	Carrier phase GNSS processing software (process QC), Position.exe (cross checks).
Real Time Kinematic GNSS (RTK)	Procedural, layout	Vector	Land/TZ receiver and source layout. Vibrator real-time positioning.	Base station, antenna height and errors due to signal loss.	Position.exe (GNSS QC factors and cross checks).
Post-processed Kinematic GNSS (PPK)	Procedural, layout, processing	Vector	Some LIDAR drone positioning. Future application with drone photogrammetry.	Base station and antenna height.	Position.exe (GNSS QC factors and cross checks).
Relative GNSS (RGPS)	Layout, processing	Vector	Mainly towed airgun array positioning.	Vessel laybacks, signal loss and intermittent data transfer. Filtering and smoothing problems in navigation system. Tide values and water depths.	Gundog.exe (raw data validity checks, tides and comparison of reprocessed positions), DepthCheck.exe (water depths).
Precise Point Positioning (PPP)	Procedural, layout, processing	Point	Land/TZ receiver and source layout. Vibrator real-time positioning. Control surveys. Marine positioning.	Antenna height and loss of signal.	Position.exe (GNSS QC factors and cross checks).
Inertial Navigation System (INS)	Procedural, layout, processing	Vector	Receiver and source layout where sky obscured - jungle.	Drift. Antenna heights and initialisation at base station or GNSS.	Position.exe (closures and cross checks).
Barometric Levelling	Procedural, processing	Scalar	Obsolete - receiver and source levelling in tree cover.	Drift. Sudden ambient barometric pressure changes. Antenna heights and base station.	Position.exe (closures and cross checks).
Acoustic Positioning	Layout, processing	Point	OBC/OBN/TZ receiver positioning	Vessel laybacks, defective or blocked transponders, tide and water depth, speed of sound.	Gundog.exe (raw data validity checks, tides and comparison of reprocessed positions), DepthCheck.exe (water depths).
Vessel Laybacks	Processing	Scalar	Receiver drop, acoustic and airgun positioning	Layback information entered incorrectly or course made good errors.	Gundog.exe (raw data validity checks, comparison of laybacks to previous. Comparison of new laybacks to calibration reports).
Water Depths	Processing, collating	Scalar	Shallow water/ TZ receiver and source positioning	Bad echo sounder readings, errors in production of digital elevation model or wrong application of DEM.	Gundog.exe (echo sounder), Position.exe (vertical profiles), DepthCheck.exe (check against DEM).
Tide Values	Procedural, processing	Scalar	Shallow water/ TZ receiver and source positioning	Tide gauge installation or reading errors or tide service errors.	Position.exe (TG installation checks against water level), Gundog.exe (checks against published values).
Aggregation of Data	Collation	N/A	Any data where different positioning techniques are used especially TZ / urban.	Incorrect editing of data or failure to update data.	Position.exe (Comparison of independent QC generated dataset & interestion checks).
Final Data	Final presentation	N/A	All survey types	Header errors, misleading headers, data format, data cross reference validity (SPS X vs R, S).	Position.exe (header and format checks), Fold.exe (format and cross reference checks).