Aquadopp current meter

The most versatile 3D ocean current meter available

Aquadopp 3D current meterThe Aquadopp is probably the most versatile single-point current meter on the market. It is cost-effective, robust and has a wide range of applications. The system electronics integrates accurate Doppler velocity measurements with standard sensors such as temperature, pressure, tilt, and compass. It is low maintenance, has no moving parts, requires no recalibration, and has no zero-point drift over time. The instrument can be used in real-time applications but also comes standard with an internal recorder, batteries and a highly sophisticated power management that makes it the system of choice for self-contained deployments.

The Aquadopp includes a complete suite of Windows® software for real-time data collection and for planning and control of a self-contained deployment. It is also designed to be integrated with third party controllers using the RS232/RS422 interface (binary or ASCII), analog outputs, or from a Windows® computer using ActiveX controls.


Applications

The flexible transducer design is the key to the wide range of Aquadopp applications. Instead of using machined parts, the sensor head is molded to allow the transducer beams to point in any way imaginable. New configurations are made continually and some of the more common ones can be found in the Aquadopp brochure, which can be downloaded here.

  • The most common Aquadopp application is classical in-line mooring use, where one or more instruments are mounted on a rope or cable that stretches from the bottom to a subsurface float. In some cases, the instrument is clamped to the rope, while in others the instrument is mounted in the Aquafin (see here for more info), which is bolted into the mooring line. Typical unique reasons for using the Aquadopp in mooring lines is the use of the diagnostic mode, the large number of auxiliary parameters that are collected (acoustic signal strength, tilt, compass, etc) and the choice of all-plastic and titanium materials in the design. The variable power output makes it possible to get longer deployment times in waters with high scattering levels.
  • The Aquadopp can be combined with other sensors, such as Valeport or MicroCAT CT sensors to include conductivity and with an OBS to measure turbidity simultaneously. More on this can be found here.
  • Many Aquadopps are fixed mounted, either on surface buoys, on pilings, or on bottom frames. The main challenge is then to ensure that the measurements are undisturbed by the mounting structure. In these cases, the programmable blanking and the flexible transducer configuration is a huge advantage. For every mounting structure there is a corresponding transducer configuration that allows high quality measurements to be gathered.
  • In channels, rivers, and in harbors, the Aquadopp can be side-mounted on the wall to avoid sedimentation on the sensor head. The acoustic beams are then projected horizontally into the flow. In this case, the currents can be measured as far as 5 m from the mounting point and the instrument operates as a 2D sensor, measuring only the two horizontal components.
  • Finally, the Aquadopp can measure wave height, period, and direction using what is commonly referred to as PUV processing. This means that the 2D velocity (U and V) is measured at 1 Hz intervals along with the pressure sensor (P) and later processed with the Nortek QuickWave or Matlab routines that can be downloaded from the Nortek forum. As a wave sensor, the Aquadopp requires extra memory, but it is clearly the most cost-effective PUV instrument in the market. More about the possibilities and limitation of the PUV wave processing can be found here.

 

Nortek shipped the first Aquadopps in 1998. Today, it is used by scientists and engineers at well-known oceanographic institutions worldwide. Please contact Nortek or your local representative for a detailed customer reference list.


Diagnostic Mode

In addition to the regular data collection, the Aquadopp can be set to collect data at 1Hz for a specified duration and at user specified intervals. This diagnostic mode is a unique feature for the Aquadopp. This mode was originally introduced to learn more about mooring motion, but it quickly proved popular also for wave data collection.