Reson SeaBat 7125 ROV, Руководство оператора

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SYSTEM PERFORMANCE AND DATA TYPES
SeaBat 7125 ROV Operator‟s Manual
Page 108 May 30, 2011
Version 3
7.3.3 Quality Filter
A quality filter makes it possible to not display or export bottom detection points which do
not pass the quality criteria. Enabling the quality filter (see
section 5.7.2.5 Quality Filter )
has the following effects:
The corrected bathymetric data record will only contain the detection points
that pass the quality filtering. A flag will be set in the record to indicate that the
quality filter was applied.
The dedicated snippets record will only contain the detection points that pass
the quality filtering. A flag will be set in the records to indicate that the quality
filter was applied.
The Primary Display wedge and Snippets displays will only show points that
pass the quality filtering.
The options Show Rejected (selected by right-clicking the wedge display) and
Rejected Items (in the drop-down menu on the Primary Display Settings tab)
will be disabled (see Display Points / Filters in
section 5.7.4 Primary Display
Settings ).
For details on settings for the quality filter, see
section 5.7.2 Detection Settings .
7.4 Uncertainty Estimation
The calculation of Total Propagated Error (TPE) is used to aid the surveyor determine
the sounding quality of the bottom detection point. The calculation is done by statistical
methods, typically in the data acquisition software. One of the inputs into the TPE
calculation is the sounding measurement error as computed in the sonar system. Other
error sources include position, draft, squat, load, tide geodetic calculations, lever arms
calculations, timing offsets, speed, heading, attitude, and sound velocity.
In the sonar processor, the error associated with bottom detection is computed
separately for amplitude, phase, and blended detection methods. This value is exported
as a field in both raw and corrected bathymetry records.
The uncertainty value is normalized to the detection point by dividing the absolute range
error (number of samples) by the detection point (fractional sample number). For example:
Absolute range error: 0.8 samples
Fractional sample number of detection point: 120.2
Uncertainty = 0.8/120.2 = 0.006655574
When the Uncertainty option is active, a color legend is shown on the wedge display.
For instructions on how to display the uncertainty, see Bathy Point Color
in section 5.7.4
Primary Display Settings .