Download SES-2000 User's Guide

190
9.5
SES 2000 User’s Guide
SES-2000 Parametric Sub-bottom Profilers
9.5.1 Directivity / Footprint
The SES-2000 sub-bottom profilers transmit very narrow sound beams, the half-power beam
width is about ±1.0° – ±1.8° for the different systems, see appendix for details.
9.5.2 Beam Steering
Most of the SES-2000 systems provide electronic beam
steering and stabilization in a range of ±15°, see
appendix for technical specs. This feature is useful to
compensate movements of the ship (roll, pitch) by
steering the sound beam always exactly vertically.
Another application for controlled beam steering is to
direct the sound beam perpendicular to the seafloor
while working on slopes.
Another application for controlled beam steering is the
search for objects by transmitting beams at different
angles subsequently as illustrated in the figure.
9.5.3 Centre Frequency / Pulse Length (Bandwidth)
The SES-2000 sub-bottom profilers cover a wide range of transmission frequencies. The
centre frequency is adjustable in the range of about 4 – 15kHz for most systems (2 – 7kHz for
the SES-2000 deep). The pulse length can be adjusted in the range of about 66 – 800µs for
most systems. The centre frequency and bandwidth of the receiver will be adapted according
to the selected transmission frequency and pulse length. Technical specs for the different
systems are given in the appendix.
With the SES-2000 sub-bottom profilers it is
possible to transmit very short sound pulses, the
shortest pulse length is 66µs (15kHz / 1cycle) for
most systems. Due to the extremely high
transducer bandwidth the sound pulses show
nearly no ringing effects at their trailing ends. This
is illustrated in the figure.
source signal (acoustic)
Innomar Technologie GmbH