Klein Marine Systems, Inc. HYDROCHART 3500, Руководство по эксплуатации и обслуживанию

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CHAPTER 3 Setup and Test
HydroChart 3500 Sonar System Operations and Maintenance Manual P/N 11210087, Rev. 03
3.10.1 Static Position Offsets
It is necessary to first measure the static position offsets between the Sonar Head
Unit, the position sensor and the motion reference unit, relative to some reference.
These measurements will provide the necessary data for applying lever-arm
corrections to the final bathymetric solution. SonarPro provides an interface to
record these offsets in the Ship Geometry Setup dialog box such that they can be
recorded along with the sonar data to provide real time correction during data
acquisition. See the "SonarPro User Manual" for more information.
3.10.2 Latency Error
This test will provide a measurement of the latency error, or time, in the overall
system, which manifests itself as a position error in the processed data. It is
recommended that lines be run in the same direction and at different speeds over
an area with a prominent bathymetric feature. This will offset any effects due to
pitch bias. The greater the speed difference the more accurate the measurement.
The latency can be derived by measuring the along-track displacement of depth
measurements over the bottom feature.
3.10.3 Roll Bias Test
This test determines the athwartship alignment error between the transducer arrays
and the motion reference unit as well as any additional roll axis bias error in the
motion reference unit. The result is a roll correction which can be used during post
processing operations. For the roll bias test you should choose a relatively flat area
of the sea bottom and run at least two reciprocal lines 200–300 meters in length at
equal speeds in both directions.
3.10.4 Pitch Bias Test
Pitch bias is similar to roll bias, except that pitch error lies in the along-ship’s
fore-aft axis. This error occurs when the motion reference unit and the transducer
arrays are not pitch-aligned; that is, they are not mounted on the same fore-aft axis.
The resulting error changes the apparent location of a feature and is proportional to
water depth. In addition, along-track displacement error increases as water depth
increases. For the pitch bias test the survey vessel should run reciprocal lines on a
sloped bottom, preferably on the order of 10–20 degrees, for 200–300 meters. It
may be possible to use a channel feature instead of a long sloping bottom. Speed
for the test should be equal for both lines.