| The EM 710 multibeam echosounder is a high to very
high resolution seabed mapping system capable of meeting all relevant survey
standards. The system configuration can be tailored to the users requirement,
allowing for choice of beam widths as well as transmission modes. The minimum
acquisition depth is from less than 2 meter below the transducers, and the
maximum acquisition depth is approximately 1200 meters, somewhat dependant upon
array size. Across track coverage (swath width) is up to 5.5 times water depth,
with a maximum survey depth of 1700 to 2000 meters. |
| EM 710 Multibeam echosounder models |
There are three basic versions of the EM 710
multibeam echosounder each with different range performances:
- EM 710 - Full performance version
- EM 710S - CW pulse forms only
- EM 710RD - Short CW pulse only
|
| Defining a new resolution standard for bathymetric surveys |
| One of the goals when we developed the EM 710
0.5x1 multibeam echo sounder system was to offer to the market a higher standard
of resolution than previously possible. The improved resolution is provided by
the 0.5 degree, focussed transmit beam - in combination with high density
processing applied to the high number of dynamically focussed receive beams. The
0.5 degree transmit beam has a very small footprint, only 85cm long at 100m
depth. So in order to ensure 100% bottom coverage even at high survey speeds we
developed a new scheme by which 2 complete sounding profiles are generated for
each ping cycle. By reducing the swath width, the operator can also increase the
ping rate, see the graph below:
 |
| Survey speed |
| So at
100m depth, with full swath width +/-70 degrees the system has 2 pings per
second, or 4 sounding profiles. The maximum survey speed while maintaining 100%
bottom coverage is then 3.4 m/sec or 6.8 knots. By reducing the swath width to
+/- 55 degrees, the ping rate is increased to 3.4 and the survey speed can then
be raised to 11.5 knots. Each sounding profile consists of 400 soundings. |
