1. Communications Technologies Bertinoro 2009
Teledyne RD Instruments Leaders in Acoustic Doppler Current Profilers and Doppler Velocity Logs
Communications Technologies Bertinoro 2009
Welcome and Thank You for joining us!
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Measuring Water in Motion and Motion in Water

2. Measuring Waves Accurately Workhorse Waves Array ADCP
Darryl Symonds
Director of Marine Measurements Product Lines
Teledyne RD Instruments

3. Waves Measuring Techniques
Pressure Sensor Array
Triplet Processing
Orbital Velocity Array

4. Pressure Sensor for Waves
Use a single pressure sensor to measure the change in the water surface height; provides non-directional waves data (Wave Height and Period)
Use an array of pressure sensors to measure the change in the water surface height at several locations at once; provides direction waves data (Wave Direction)

5. Triplet Processing for Waves
Uses 3 parameters to provide waves data
Measure changes in the height of the water to provide non-directional waves data (Wave Height and Period)
Measure water velocity to provide directional waves data
Techniques
PUV – Pressure + U/V Horizontal Velocity Vectors
UVW – Vertical Vel + U/V Horizontal Velocity Vectors
SUV – Vertical Range + U/V Horizontal Velocity Vectors

6. Orbital Velocities for Waves
Measures the orbital velocities below the surface at multiple layers to provide 4-20 independent measurements of the orbital velocity created by a passing wave

7. Waves energy propagation

8. Orbital Wave Energy is flattened due to the bottom

9. Energy of short waves decays with depth

10. RDI ADCP Waves Measurements Techniques
WH Sentinel
Monitor ADCP
WH Horizontal
ADCP
NEMO

11. RDI Sentinel ADCP Waves
Measurements:
Current Profile
Echo Intensity
U/V Velocity
Vert Velocity
Pressure
Surface Track
WH Sentinel
Monitor ADCP

12. Triplet Processing – PUV/UVW
Pressure = Non Directional Wave Data: Hs, Tp
UV Velocity Bin = Directional Wave Data: Dp
UVW Velocity Bin = Non Directional and Directional Wave Data: Hs, Tp, Dp

13. Surface Tracking – 4 Beams
4 Beam Array = Non Directional: Hs, Tp
UV Velocity Bin = Directional Wave Data: Dp

14. Orbital Waves Processing
4-20 Independent Orbital Fluctuation Sensors
Directional Spectrum with IMLM
To go to the horizontal, the directional array has changed form, but it is still an array. The same basic iterative maximum likelihood technique can be used to obtain direction. We have lost our redundant measures of the non-directional spectrum. The beams will never intersect the surface, and therefore can not measure the range. The pressure sensor is no longer measuring in the center of the array – it is in fact poorly located when the existing of the mounting structure is taken into account. This leaves us with only the orbital velocity measurements to measure the non-directional spectrum.

15. Data Provided by the WH Sentinel ADCP Waves System
Simultaneous Currents and Waves
Current Profile Information
East/North/Vertical Velocity
Error Velocity
Correlation
Echo Intensity
Percent Good

16. Data Provided by the WH Sentinel ADCP Waves System
Simultaneous Currents and Waves
Wave Information
Processed Parameters (Height, Period, Direction)
Non Directional Spectra (3 methods; Orbital, Surface Track, and Pressure)
Directional Spectra

17. Significant Wave HEIGHT
Height, Period, Direction, Tides Time Series
Significant Wave HEIGHT
Peak PERIOD
Peak DIRECTION
TIDES

18. Non Directional Spectrum (Wave Height Spectrum) Orbital Array Velocity
Surface Tracking
Pressure Sensor

19. Comparing Methods Triplet (PUV) Narrow Band Array RDI Vertical
Triplet
(PUV)
Narrow
Band Array
RDI Vertical
ADCP Array
Frequency NA
600kHz
# Sensors 3 12
Signal Processing
Band (U/V)
BroadBand
Bin Size (meters) 2
0.7
Measurement
Precision (cm/sec)
1.0
5.7
3.9
Array Aperture (m)
Assumes 20 meter
depth
Single
Point 10 7

20. Comparing Directional Resolution
RDI VADCP Array
NarrowBand Array
Triplet (PUV)

21. Summary of the WH Sentinel ADCP Waves System
RDI’s ADCP Wave Array provides several instruments at the same time in one package
current profiling AND
directional wave gauge AND
water level device
Directional Wave Analysis
array type measurement refines direction resolution
Reveals and corrects for bias due to wave-current interaction
3 independent methods collected for comparison and quality assurance

22. RDI ADCP Waves Measurements Techniques
Horizontal Current Profile
Echo Intensity
U/V Velocity Array
Pressure
WH Horizontal
ADCP

23. Orbital Waves Processing
Horizontal ADCP is at a single layer below the surface
Directly measures the entire wave field.
Directional Spectrum with IMLM
To go to the horizontal, the directional array has changed form, but it is still an array. The same basic iterative maximum likelihood technique can be used to obtain direction. We have lost our redundant measures of the non-directional spectrum. The beams will never intersect the surface, and therefore can not measure the range. The pressure sensor is no longer measuring in the center of the array – it is in fact poorly located when the existing of the mounting structure is taken into account. This leaves us with only the orbital velocity measurements to measure the non-directional spectrum.

24. Comparing Systems Triplet (PUV) Narrow Band Array RDI Vertical ADCP
Triplet
(PUV)
Narrow
Band
Array
RDI
Vertical
ADCP
Horizontal
Frequency NA
600kHz
300kHz
# Sensors 3
4-20 15
Signal Processing
NarrowBand
BroadBand
Bin Size (meters) 2
0.7 8
Measurement
Precision (cm/sec)
1.0
5.7
3.9
1.1
Array Aperture (m)
Assumes 20 meter
depth
Single
Point 10 7
140

25. Summary of the WH Horizontal ADCP Waves System
Real Time Measurements in Ports, Navigation Channels, and Oil Platforms
Improves Directional Wave Spectra
Improves Long Wave Measurement Performance
Lower system reduced Maintenance Cost
Fugro GEOS arranged a deployment from the Global Santa Fe drill ship CR Luigs, which was under contract to BHP Billiton for deep drilling in the Gulf of Mexico at the time. Here is the CR Luigs as we approached her in the helicopter, and as you can see she is a pretty massive ship - about 230 m long, with 35 m of beam and 10 m of draft. Fugro GEOS already had a 75 kHz broadband ADCP deployed on this ship, which they suspend over the side of the ship using a dual winch system with spreader bars between the two lifting cables. Fugro GEOS manufactured a new spreader bar to attach the H-ADCP to this existing installation, and we attached it about 10 m above the broadband. The illustration shows the H-ADCP mounted above the broadband. Here on the right you can see the complete installation as we are lowering it into the water. The broadband is already beneath the surface.

26. Waves Measuring Setup Which Processing Method?
What is the Data Collection Interval?
What about Real Time Data Collection?

27. Orbital Velocity Array Considerations
Benefits
Concerns
Collect data sub surface
Must be a fixed bottom mount
Waves data information is collected near the surface
Selection of proper depth cells
Automatic waves depth cell selection
Must ensure the pressure sensor is working correctly
Collect simultaneous current profiles and waves data
Power consumption for waves pinging requires more batteries
Collect data at water depths 5-80m
Upper cutoff frequency lowered as depth increases
“Compressed” waves data allows for easier data output
The waves packets are large

28. Surface Track Considerations
Benefits
Concerns
Collect data sub surface
Must be a fixed bottom mount
Directly measure the surface height
Air bubbles and high sediment in the water column
Automatic waves depth cell selection
Must ensure the pressure sensor is working correctly
Collect simultaneous current profiles and waves data
Power consumption for waves pinging requires more batteries
Collect data at water depths m
Upper cutoff frequency lowered as depth increases
“Compressed” waves data allows for easier data output
The waves packets are large

29. UVW Considerations Collect data sub surface
Benefits
Concerns
Collect data sub surface
Must be a fixed bottom mount
In-directly measure the surface height
High frequency changes are attenuated at depth
Collect simultaneous current profiles and waves data
Power consumption for waves pinging requires more batteries
Collect data at water depths m
Upper cutoff frequency lowered as depth increases

30. So which Method to Use?
Data for all 3 methods is collected by the ADCP at the same time.
Each method can be separately processed by the RDI software.
Compare results if all agree then use the Orbital Velocity data
If there are differences verify if the Concerns caused a bias and select the method that does not have bias

31. Currents Only Ping Setup
Single Ping Ensembles
10min Ensemble
10min Ensemble
Multiple Ping Ensembles Evenly Spaced in Time
10min Ensemble
10min Ensemble
Multiple Ping Burst Ensembles
10min Ensemble
10min Ensemble

32. Currents Only Ensemble Setup
10 Min
10 Min
Burst Ping Ensembles 8 Pings/Ens * 6 Ens/Hr = 48 Pings/hr
10 Min
10 Min
Burst Ping Ensembles + Burst Ensembles 2 Pings/Ens * 24 Ens/Hr = 48 Pings/Hr
10 Min
10 Min

33. Waves Sampling Strategies
Waves Burst duration is User Selectable, min/typical 20mins
10min Current Ens.
10min Current Ens.
Pings for Waves Burst are 2Hz
Current Ens. Are User Selectable typical 10mins (TE Cmnd)
10min Current Ens.
10min Current Ens.
Pings for Current Ens. within Waves burst are shared with Wave Burst
10min Current Ens.
10min Current Ens.
Pings for Current Ens. outside Waves burst are at User Selected Interval (TP Cmnd)

34. Waves Sampling Strategies
Wave Burst
10min Ens.
Waves Burst interval is User Selectable: min/typical 1 per hour max 1 per 3 hours
Wave Burst
10min Ens.
10min Ens.
10min Ens.

35. RDI ADCPs AND REAL TIME COMUNICATIONS
The Doppler Volume Sampler DVS is one of the latest products produced by RDI

36. Real Time Data Requirement

37. RDI ADCP Real Time Waves
Advantages:
Remote Real Time Currents and Waves Processing
Use Orbital Waves or UVW Processing
Allows low data bandwidth applications
Stand alone or integrated
NEMO

38. RDI Integrated Real Time Options
Teledyne Benthos Acoustic Modems
SeaBird Electronics Inductive Modems

39. RDI WH with Integrated NEMO and Internal/External SBE IMM Integration Setup
Features:
All of the previous
WH Powers NEMO and IMM
Expandable Battery Integration for Day Deployments
SBE Underwater IMM with coupler and cable mount.
WH Sentinel w/RDI NEMO
WH External Battery Case

40. RDI WH with External SBE IMM Integration Setup

41. RDI WH with Internal SBE IMM Integration Setup
Insulated mooring cable.
Seawater
Ground
Anchor
Surface Buoy with Surface Modem
SBE IMM Coupler
SBE IMM Coupler
The DVS is designed to be mounted bolted to a jacketed mooring line and to have 2 way communications through an inductive modem link
The IMM link can be replaced with a connector for self-contained operation
NOAA discovered that mounting on to a mooring line is problematic, there is strumming that can bias velocity data, which RDI can compensate for by its ability to sample at 15-45hz rates
Another concern when mounting on mooring lines is the fact that you may measure currents influenced by the mooring line
RDI WH ADCP
RDI WH ADCP with IMM Coupler

42. RDI WH with Internal SBE IMM Integration Setup
Features:
WH synchronous or asynchronous with IMM
Real time data access
No interruption of asynchronous WH data
Stored data access through IMM 16KByte Loop Recorder
Powered by single WH battery for 1year; deployment duration depends on model and user setup

43. Inductive Setup Considerations
Mooring Cable Diameter
Support 9.5mm(3/8”) – 19.1mm(3/4“) diameter cables
Coupler spacers supplied to limit cable motion within coupler
Power Consumption
Power consumption for RDI ADCP
Power consumption for IMM data access
Plan for IMM power consumption during other sensor downloads
Data Format
ASCII or Binary data
Complete data or subset

44. Contacts Main Office: Teledyne RD Instruments, Inc. 14020 Stowe Drive
Poway, CA 92064
Main:
European Office:
Teledyne RDI Europe
5 Avenue Hector Pintus
La Gaude, France
Main:
China Office:
Teledyne RD Technologies:
1206 Dongfang Road, Pu Dong
Shanghai 20122
China
Main:
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Italy Representative:
Gianni Basini & Sandro Giordano
Communications Technology Pzza Guidazzi 3
Cesena Italy