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measurement accuracy that you may expect from the System if you follow the correct operating
procedures. These tables provide guidance on the vertical range and measurement accuracy that you
may expect for the targets listed. DO NOT use the tables as correction tables to refine survey results
after you have completed the survey.
Where the information contained in
coverage, you may make a series of manual measurements using a sample of the target on dry land to
derive a table that is valid for a specific target. By prior arrangement, Teledyne TSS can perform this
service before the survey using a suitable 5-metre sample length of target.
The ideal condition during the survey is for the ROV to be located centrally over the target with no roll,
pitch or skew present. Where this is impossible to achieve, you may simulate the roll, pitch and skew
conditions during tests on land and assess their effects on measurement accuracy.
6.1.3 Data Collection
During the early stages, the survey planning team will need to define the type of data required from the
survey:
The System can complete a quick and simple check on the track and depth of cover of a target by
making a series of widely spaced measurements.
Alternatively, to work to the highest achievable accuracy (for example to perform an out-of-straightness
survey), you may need to stop the ROV at closely spaced intervals to perform accurate measurements
on the target and to measure the mean seabed level with a separate profiling system.
6.1.4 System Installation Requirements
Before starting a survey the survey planning team should define the installation requirements of the
440 System. They should consider:
❐
The type of ROV to be used and where the SEP, the PSU and the coils will be mounted. The
440 System is suitable for use on most types of ROV, including towed sleds. Teledyne TSS
can offer further advice if necessary.
❐
Which communication method to use between the SEP and the SDC. This will depend upon
the characteristics of the umbilical cable. See Section 4 "Electrical Installation" beginning on
page 4-1 for guidance.
❐
Whether to use an altimeter or a rapid update profiler, and their location on the ROV.
❐
The type and capacity of data logger, and its connection and communication requirements.
❐
Whether to use an external printer with the 440 System. Teledyne TSS recommends that you
should generate a written or printed copy of the System configuration before and after the sur-
vey. This will be useful source of reference during the data analysis phase of the survey.
❐
The on board facilities for creating, displaying and recording video images from a sub-sea
camera mounted on the ROV. Consider using the video facilities to record the installation pro-
cedure of the 440 System.
The standard 440 System includes a field support kit (FSK) for use with the sub-sea installation. Only
engineers who have attended Part 2 of the relevant Teledyne TSS training course should use the FSK.
DPN 402196 Issue 4.1
Chapter 8 "System Specifications"
© Teledyne TSS
6 – Operating Procedure
does not provide sufficient
6- 3
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