Introduction; General Overview; Communications - Gemini 620pd Profiling Product Manual

1. Introduction

1.1. General Overview

The Gemini 620pd Profiling sonar is a multibeam echo sounder with a wide field of
view and rapid update rate able to provide quick feedback to the user.
The Gemini Hub is a rack mountable interface capable of driving two sonar heads,
connecting to a network via Ethernet and bringing in sensor data via RS232.
The Gemini Software is a special application which processes the data from Gemini
sonars and is capable of outputting this data across a network to be used within survey
software packages.
A Gemini Profiling System will comprise the Gemini Profiler, Gemini Hub and
Gemini Software. This manual will detail how to set this system up and cover
operation of the Gemini Software. It does not detail how the data from the Gemini
System will be used within the survey software.

1.2. Communications

There are two connection options, 100Mbit·s
automatically detect which connection is available and switch to that connection (a
different cable is required, see Section 4.7, "Cable Specification").
The VDSL option allows a single twisted pair to be used for communication to/from
the sonar at high speeds dependent on the length and quality of the cable. The Tritech
International Ltd supplied VDSL Hub takes the two wire VDSL input and bridges it
to Ethernet for simple connection to a PC.
VDSL maximises the data rate by testing the quality of the connection at start up and
adapting the speed accordingly. With VDSL there is a trade off between link speed
and noise immunity. There is a setting in the software that allows optimisation to cope
with the level of noise introduced by other parts of the system. The sonar can cope
with some electrical noise on the link but it may reduce the image transfer rate.
0695-SOM-00001, Issue: 03
Note
When using an Ethernet connection the Gemini can fully utilise a
100Mbit·s link while returning the sonar data. If it is to share an Ethernet
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link with other high bandwidth devices, such as video cameras, it is
recommended that the 100Mbit·s
surface to reduce possible network congestion.
Ethernet and VDSL. The sonar will
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devices share a Gigabit link to the
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Gemini Profiling System
© Tritech International Ltd.