5-MHz ADVOcean Expanded Description
- Contents:
- 1. Introduction
- 2. Standard ADVOcean
- 3. ADVOcean with Optional Sensors
- 4. ADVOcean Processor
- 5. Standard Features
- 6. Options
The SonTek/YSI ADVOcean (Acoustic Doppler Velocimeter Ocean Probe) is a versatile,
high-precision instrument used to measure 3D water velocity in the most challenging
applications (Figure 1). The ADVOcean is designed for
a wide range of environments including the surf zone, open ocean, rivers, lakes, and estuaries.
Figure 1. ADVOcean Probe
The ADVOcean uses acoustic Doppler technology to measure 3D flow in a small sampling
volume located a fixed distance (18 cm) from the probe (Figure 2).
The velocity range is programmable from ±5 to ±500 cm/s. Data can be acquired at
sampling rates up to 25 Hz.
Figure 2. Sampling Volume
With no zero offset, the ADVOcean can be used to measure flow velocities from less than
1 mm/s to over 5 m/s. The remote sampling volume, stability, and rapid response of the
ADVOcean make it perfect for all types of flow measurement: mean currents, waves, and
turbulent flow parameters.
The ADVOcean consists of two elements: probe and processor. The probe includes the
acoustic sensors, receiver, and optional sensors in a submersible housing. It is connected
to the processor using a custom shielded cable up to 50 m in length.
The ADVOcean processor operates from external DC power and outputs data using serial
communication or a set of analog voltages. The processor can be operated from any
PC-compatible computer or can be integrated with a variety of data acquisition systems.
For autonomous deployment (internal data storage and battery power), the ADVOcean can
be integrated as part of a SonTek Hydra system.
The standard ADVOcean probe (Figure 3) is designed for
long-term deployments in the most hostile environments. The entire probe is constructed
from 316 stainless steel, and protected from corrosion by a sacrificial zinc anode (not
shown). With no moving parts, the ADVOcean has excellent resistance to biological fouling.
For added protection, the entire probe, including the transducers, can be coated with
anti-fouling paint. The probe is connected to the processor using an underwater mateable connector.
Figure 3. Standard ADVOcean Probe
For deep-water deployments, the ADVOcean can be rated for depths up to 2000 m (the
standard depth rating is 400 m). Deep-water ADVOcean systems are commonly used on
autonomous underwater vehicles (AUVs) and remotely operated vehicles (ROVs) for detailed
microstructure measurements.
In any configuration, the ADVOcean probe is immune to zero drift and has no inherent
minimum detectable velocity. The probe calibration can only change with physical damage to
the system. No regular maintenance or re-calibration is needed.
The ADVOcean probe can include a number of optional sensors to greatly expand its
measurement capabilities. These include -- a compass and 2-axis tilt sensor allowing the
ADVOcean to report velocity data in Earth (East-North-Up) coordinates; a pressure sensor
for wave height (PUVW) and surface-level measurements; and a temperature sensor for
automatic sound speed compensation.
ADVOcean probes with optional sensors use an expanded housing (Figure 4) constructed from
acetyl (Delrin), and have the same reliability and performance as
the standard ADVOcean probe.
Figure 4. ADVOcean Probe
with Optional Sensors Housing
The ADVOcean processor can be housed in two different ways depending upon whether the
processor will need to be submerged. The ADVOcean processor operates from DC power and is
typically connected to a portable computer running SonTek's powerful data acquisition
software. It can also be integrated with a variety of data acquisition systems using
serial communication or the analog output voltages.
4.1. ADVOcean Splashproof Processor
For applications where the ADVOcean processor does not need to be submerged, the
processor (Figure 5) is enclosed in a splashproof housing with
connectors for the probe, power, communication, and auxiliary input/output (analog
voltages and external synchronization). The splashproof housing can include an internal
rechargeable battery (capacity for 5-10 hours of operation).
Figure 5. ADVOcean Splashproof Processor
4.2. ADVOcean Underwater Processor
The ADVOcean processor can also be housed in an underwater canister (Figure 6) with separate underwater mateable connectors to the probe
and the external interface (power, communication, and auxiliary input/output). The power
and communication cable can be up to 1500 m long for deployment in a wide range of environments.
Figure 6. ADVOcean Underwater Processor
The underwater housing is rated for deployment depths to 500 m. For deep water
applications, the processor can be enclosed in a user-supplied pressure housing (SonTek
can supply all necessary cables and bulkhead connectors). SonTek can also supply custom
high-pressure housings upon request.
ADVOcean systems include the following standard features.
ADVOcean Standard Features
| ADVOcean Probe |
ADVOcean Processor |
- Factory calibration (can only change with physical damage to the probe)
- Programmable velocity range from ±5 to ±500 cm/s
- Submersible to 400 m
- 10-m cable to processor (50-m max.)
|
- Dual serial communication (RS-232 standard, RS-422 for cable lengths to 1500 m)
- Four analog output voltages (3 velocity, 1 signal strength) for integration with
analog data acquisition systems
- Hardware synchronization with external sensors using sync input and output
|
Several options, including the following, are available for use with ADVOcean systems.
6.1. Rechargeable Battery
The ADVOcean processor in the splashproof housing can include a rechargeable lead-acid
battery for short-term field deployments. The battery is installed in the same housing as
the processor and has capacity for 5-10 hours operation.
6.2. RS-485
The ADVOcean processor can configured to use RS-485 serial communication to control and
collect synchronized data from up to 15 systems. All systems are connected on a single
cable to one computer. Data collection is controlled by SonTek software.
6.3. Compass/Tilt Sensor
The compass and 2-axis tilt sensors allow the ADVOcean to report velocity data in Earth
(East-North-Up) coordinates. The sensor has a built-in calibration feature to compensate
for magnetic distortion. The user can easily re-orient the compass for up, down, or
side-looking operation.
6.4. Deep Water Deployments
The standard ADVOcean probe (without optional sensors) can be rated for deployment
depths to 2000 m.
6.5. Pressure Sensor
A strain gage pressure sensor can be installed in the ADVOcean to measure wave height
(PUVW for directional wave spectra) and deployment depth. The pressure sensor is available
in a variety of ranges.
6.6. Temperature Sensor
Any ADVOcean with compass/tilt or pressure sensor includes a temperature sensor to
compensate for changes in sound speed. Sound speed is used to convert Doppler-shift to
water velocity.
6.7. The Hydra -- Autonomous Operation
The ADVOcean can be integrated with a wide range of other sensors as part of SonTek's
Hydra autonomous ocean sensor system (including internal data storage and battery power).
For more information on the Hydra system, go here.
Details about this SonTek/YSI product can be found at:
