Triton Isis - Manual (Page 19)

June 2004 Isis® Sonar User's Manual, Volume 1 5
the same serial port. Alternatively, another serial port can be used. Custom
interfaces can also be created by Triton Elics for sonars whose telemetry
data is transmitted in a specific manner.
1.2.3 Real-Time Data Processing
With real-time processing, it is possible for the user to interpret features
visible in the processed data (but perhaps not in the raw data) as they are
collected. This allows decisions to be made in real time based on these
interpretations.
In side-scan sonar data, Isis removes the water column, corrects the slant-
range, and corrects the along-track speed — all in real time. These features
ensure accurate visualization of the seabed. With the advent of real-time
mosaicking, a true, georeferenced picture of the area can be generated as
the survey occurs.
Processing data in real time does not preclude saving the raw data. During
acquisition Isis always saves the raw, uncorrected data.
1.2.4 Combining Navigational and Acoustical Data
While Side Scan Sonar imagery and Multibeam Sonar data is acquired,
other forms of data can be entering Isis via the serial ports. For example, a
navigation device or an integrated navigation computer may be connected
to a serial port in the Isis system. Also, towfish telemetry (including pitch,
roll, heading and depth) are often interfaced and sometimes combined with
the navigation data. All of these data are merged into a standard XTF data
format in the host computer before being passed on to a mass storage
device.
Data fusion is an important aspect of the Isis design. The simultaneous
acquisition of navigation data and acoustic data allows for real-time
positioning of any pixel of imagery (geocoding). If the towfish is crabbing or
yawing while towfish telemetry is interfaced to Isis, these corrections will
also be included in geocoded positions. Navigation data entering Isis can be
used to determine the speed over ground. This information is employed to
correct the imagery in real time or in playback mode, allowing rectilinear
rendering (that is, equal scale in both the along-track and across-track
directions).
All of the data acquired can be used to generate a side scan sonar “map” or
“mosaic,” which can be imported into TEI’s GIS Delph Map package and
combined there with almost any other georeferenced data.
Chapter 1: Isis Overview