The Bathy-500HD Survey Echo Sounder provides a high-contrast thermal chart record complete with alphanumeric annotation
of important parameters such as geographic position, depth, speed of sound and offset for draft/tide. Real-time viewing of all
parameters is provided to the user via front panel liquid-crystal display. Position input can be from either a standard C/A GPS
receiver or differential GPS system. Depth data is available to external devices in digital form, via a versatile interface, whose
format is selectable by the user using the front panel keypad. The user may obtain digital depth data output, in various industry
standard RS-232 formats or NMEA-0183. The ability to accept external annotation input from various PC-based hydrographic
software is standard in the Bathy-500HD.
Unit set-up and parameter changes are accomplished via the keypad. Important parameter values are retained by the unit in
non-volatile memory when power is removed. A real-time internal clock provides time and date stamping of the chart record.
The Bathy-500HD is equally well suited for both applications which involve rapid depth of channel determination by viewing
the chart record and for detailed hydrographic surveys whereby automatic operation and unattended logging of digital depth
data is desired.The use of embedded parallel microprocessor architecture allows for operation of the chart recording function
simultaneously with digital display and data outputs, while further having the real-time capability to implement a proven
weighted bottom detection technique, adaptive bottom tracking gate and other advanced signal processing.
Entirely portable, the Bathy-500HD can be operated on any vessel of opportunity since a wide range of A.C. and D.C. input
voltages can be used. Your Bathy-500HD is capable of operation on various frequencies as selected by the user; See Section
3.3.1 for frequency selection procedure. Space is provided in the rear of the unit to store the various transducer types. Since
scale annotation is printed on the chart along with bottom features, only one type of chart paper is required; The user need not
change paper type when changing measurement units from feet to meters or vice-versa.
Echo sounding measures water depth by measuring the time interval required for ultrasonic sound waves to travel, at a known
velocity, from a known point (a vessel) to a reflecting surface (water bottom) and return. If the time is measured between the
transmission of a sound wave and the reception of its echo, the depth may be determined by multiplying one-half of this time
interval by the velocity of sound in the water column.
For accurate surveying, sound velocity (more correctly referred to as speed of sound since it is really a scalar value) must be
determined and entered into the echo sounder. Sound speed in water is dependent upon the salinity, temperature and depth. For
instruments that operate in shallow depths, as is the case for the Bathy-500HD, depth is not a major factor effecting sound
speed, so such is not considered in this manual. Complete details regarding the various methods available to the user to
measure or estimate sound speed is included in the chapter which describes unit operation (Section 3.0).
Under optimal desired survey conditions, only a single trace will be shown in the water column; That, of course, representing
the water bottom. Various conditions do however exist which result in other marks between the zero line and obvious water
bottom. Physical conditions such as a rapid temperature gradient (thermocline) or density variation (pycnocline) can form an
acoustically reflective layer between the zero mark and true bottom. Further, dense biological material (plankton) may have the
same effect While the user may,in many cases, easily recognize these layers (as represented on the paper chart), automatic
digital depth tracking, display and output may be effected. In such cases, a blanking feature (manual gate feature on the Bathy500HD)
is required for robust, reliable unattended surveying.
Features:
Interleaved Dual Frequency Operation
Compatible with Hypack and HydroPro™ Software Processing Packages****