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Directional Waverider 4

The Directional Waverider that integrates wave and current measurements

The wave sensor of the Directional Waverider equipped with the Acoustic Current Meter option (DWR4/ACM for short) is identical to the sensor in the well-known Directional Waverider MkI, II and III. Processing of the measured data is now performed at the doubled sample frequency of 2.56 Hz. The high frequency limit of the heave and direction signals is shifted from 0.58 to 1.0 Hz. With this choice, the high frequency limit of the wave buoy is determined by the hydrodynamic response of the hull, not by the onboard instrumentation.

In addition, the DWR4 transmission protocol allows for a superior heave and horizontal displacement resolution. Easy comparison of the new DWR4 output to the familiar DWR-MkIII results is facilitated in the accompanying Waves5 software suite.

  • Sensor
    wave motion sensor based on a stabilised platform, accelerometers, and magnetic compass
  • Measures
    – wave height for wave periods of 1 to 30 seconds, accuracy 0.5 % of measured value
    – wave direction
    – surface current
    – water temperature
  • Additional features
    – GPS for buoy monitoring and tracking through HF link
    – internal logger
    – power switch
    – LED flash antenna
    – 0.9 m (0.7 m) diameter spherical hull of AISI 316 including eccentric mooring eye
    – optional Cunifer hull, excellent against bio-fouling
    – 1.6 years (10 months) battery life
Current Meter
Method: Doppler
Cell size: 0.4 m to 1.1 m from surface
Update rate: every 10 minutes
Sensors: three 2 MHz acoustic transducers
Range: 0 to 3 m/s, resolution 1 mm/s
Accuracy: 1% of measured value ± 2 cm/s
Std. (1σ): 1 to 3 cm/s (depending on wave height)
Range: 0° to 360°, resolution 0.1°
Accuracy: 0.4° to 2° (depending on latitude), typically 0.5°
Reference: magnetic north
Wave Sensor
Type and processing
Type: Datawell stabilized platform sensor
Sampling: 8-channel, 14 bit @ 5.12 Hz
Data output rate: 2.56 Hz
Processing: 32 bits microprocessor system
Range: -20 m to +20 m, resolution: variable,
1 mm smallest step
Sampling: < 0.5% of measured value after calibration
< 1.0% of measured value after 3 years
Period: 1.0 s to 30 s
Range: 0° to 360°, resolution: 0.1°
Heading error: 0.4° to 2° (depending on latitude), typically 0.5°
Period: 1.0 s to 30 s (free floating)
1.0 s to 20 s (moored)
Reference: magnetic north
Water temperature
Range: -10 °C to +50 °C, resolution: 0.01 °C
Sensor accuracy: 0.1 °C
Measurement accuracy: 0.2 °C
Integrated data logger Compact flash module 1024 Mb to 2048 Mb
LED flashlight Antenna with integrated LED flasher, colour yellow (590 nm), standard length 35 cm, “Standard pattern”: 5 flashes every 20 s, “Increased pattern”: 5 flashes every 15 s.
GPS position 50 channel, update every 10 minutes, precision < 5 m
Datawell HF link Frequency range 25.5 to 35.5 MHz (35.5 to 45.0 MHz on request)
Transmission range 50 km over sea, user replaceable.
For use with HVA compatible Datawell RX-C4 receivers.
Power consumption 522 mW
Material Stainless steel AISI 316 or Cunifer 10
Hull diameter 0.7 m or 0.9 m (excluding fender)
Weight Approx 109 kg 0.7 m AISI 316, 113 kg 0.7 m Cunifer 10
Approx 192 kg 0.9 m AISI 316, 201 kg 0.9 m Cunifer 10
Batteries 0.7 m operational life 11 months
0.9 m operational life 23 months
Type: Datacell RC27B (270 Wh black)
Power switch Data files are closed and secured
Temperature range Operating: -5 °C to +35 °C
Storage: -5 °C to +40 °C (+55 °C short term, weeks only)
Hull painting Brantho-Korrux “3 in 1” paint system (no anti-fouling)
Optional features
Air Temperature
Measuring height: 2 m above sea surface
Temperature range: -20 °C to +70 °C
Resolution: 0.01 °C
Exposed accuracy: ±0.5 °C (±1.0 °C when solar induced uncertainty detected)
Power switch Data files are closed and secured
Solar power system Solar panel combined with BOOSTCAP capacitors
Peak power: 5 W, Capacity: 2 Wh
Transmission Iridium SBD, Iridium internet, GSM internet and Argos
A picture of a CAT4 antenna with a background of the sea

Compact Air Temperature (CAT4)

The CAT4 is a meteorological air temperature sensor integrated in the HF-antenna of the Directional Waverider. It consists of four individual sensors that have different radiative properties and will therefore measure different temperatures. The actual air temperature is derived from these different temperatures. External influences that might affect the measurements, such as evaporative cooling, are detected for validation.

Software Waves5

Waves5 is Datawell’s newest Microsoft Windows based software package for data acquisition, processing, and display of wave data by Datawell Waveriders – directional and non-directional. Measuring oceanographic parameters does not solely involve gathering data and logging it. To get a complete view of the governing conditions at sea, it is desirable to post-process and present the data as well. The oceanographic parameters measured with a Waverider are made available to the user by data transfer like the HF-transmitter, GSM- and satellite links and data processing, storing and presentation software. The latter is taken care of by Waves5, the Microsoft Windows based software package developed by Datawell.
A picture of a Maximum Entropy Method directional spectrum in Waves5.


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