ADCPs can produce water velocity measurements in any of four frames of reference: beam frame, instrument frame, vessel frame and earth frame. Understanding velocity frames of reference is important for data inspection/interpretation and for selecting the correct one for your application.
Beam Frame
Beam frame means water velocity along the direction of the beam (beam 1, beam 2, beam 3 …). These are raw measurements determined independently by each transducer.
Instrument Frame
Instrument frame means water velocity in a coordinate system relative to the device (X, Y, Z). The X, Y and Z axes are always orientated the same relative to the transducer head. When the X-Y plane is level, the internal compass measures the orientation of the Y-axis relative to magnetic north.
Vessel Frame
Vessel frame means water velocity with respect to the vessel (starboard, forward, up/mast – axes that are more commonly known as pitch, roll and yaw).
Earth Frame
Earth frame means water velocity with respect to Earth (east, north, up), i.e. true orientations. This is a stable frame of reference for ensemble averaging and therefore the most commonly used.
For Origin ADCPs using Origin Viewer you can swap between different frames of reference.
Contact [email protected] for more information.
Origin Scheduler is a software tool designed for configuring a measurement schedule prior to deployment, and is provided as standard with all Origin ADCPs.
Origin Scheduler allows operations to be de-risked by enabling you to plan and configure your ADCP sampling schedule prior to deployment.
This intuitive PC application has a number of features to facilitate an optimised and successful ADCP mission.
- Input details of your Origin ADCP and mission, including environmental parameters, deployment duration and mode, and battery quantity.
- Plan and configure your sampling schedule simply by inputting variables including start and end depths, number of cells, blanking distance, ping rate, and capture and sleep durations.
- Select to log high resolution data formats if you are interested in more than just PD0 data. Note this will increase disk usage.
- Set-up two schedules to be run together to allow for dual monitoring tasks to be performed with a single device.
- Check mission critical outputs of expected battery usage and expected disk usage to ensure you won’t run out of power or disk space with your intended measurement schedule.
Note: a dual battery Origin 600 device will ping continuously at 4 Hz for 2 weeks, but lifespan will be increased to months with a duty cycle mode of operation (e.g. lifespan of 3 months on schedule of 4 Hz for 1 min and sleep for 14 min). Similarly for the Origin 65, with a triple battery pack the device can ping continuously on 1 Hz for weeks but operating on a duty cycle can last for several months and even years (e.g. lifespan of 6 months on schedule of 1 Hz for 1 min and sleep for 14 mins).
If you do decide that you want to reconfigure your Origin measurement schedule whilst in operational conditions, there are two ways to achieve this: (1) Using the Origin Portal Web UI via ethernet connection, or (2) acoustically using the Origin Topside software and a topside modem when the device is already in the water.
Contact [email protected] for more information.
ADCPs have been used by the commercial and academic community alike for around half a century, but today there is an ongoing desire and increasing demand of users to access ADCP data remotely. With an integrated acoustic modem and Edge data processing functionality, Origin ADCPs provide a solution.
What are the benefits of remote ADCP-data access and what requirements does this meet?
The major benefits and reasons for the increasing requirement for remote / in situ ADCP-data access are four-fold:
- It enables on-site implementation of quality checks / control tests required to establish best-practice and data assurance.
- It enables near real-time operations for customisation and optimisation of procedures.
- It enables near real-time monitoring for time-critical decision-making.
- It supports post-capture data harvesting for (actionable) insights during monitoring periods, without the need for device recovery. This includes using a USV to reduce cost, carbon output and safety risk.
What is the present reality?
The present reality for the majority of subsea ADCP deployments is the system is deployed for a period of time to gather data and is then retrieved for data offload and analysis. A major limitation of this mode of operation being that users can only inspect data and confirm its validity once the device has been recovered, which risks compromised or even lost data.
To overcome this limitation, ADCPs can be deployed alongside an acoustic modem to enable remote communications. However, there are cost and risk implications to this approach, e.g. prevention of substantial/full data transfer via acoustic telemetry primarily due to limited bandwidth, and integration costs and complexity. Cabled operation is another alternative, but suffers from additional risk of damage to the cable, electrical noise pickup from mechanically coupled infrastructure, and is unsuitable in some environments such as deep water or dynamic sites.
What is the Sonardyne solution?
The Origin series of ADCPs combine a stand-alone ADCP with integrated acoustic modem and customisable Edge data processing functionality for delivery of remote ADCP-data access and all of the associated benefits.
In more detail, Edge data processing permits customisation and size-optimisation of ADCP data during the instrument’s deployment. This essential data can then be exported over the acoustic modem. Ultimately, Edge will maximise the performance of the modem in a ‘critical information’ data transfer capacity, and will give unprecedented ability to change in-field functionality and retrieve relevant data without recovering the ADCP.
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Contact [email protected] for more information.
Origin 600 has a five-beam configuration including one vertical beam. Three beams are sufficient to measure three-dimensional water velocities, but including more provides redundancy and the ability to estimate water velocity errors. A vertical fifth beam in particular expands the capability of the ADCP for purposes including determination of wave metrics
The vertical beam is located at the centre of symmetry of the end cap, and the other four beams are equally spaced in azimuth with a 25-degree Janus angle. Each beam has a beam width of ±1 degrees.
Contact [email protected] for more information.
Origin 65 has a four-beam configuration; this provides redundancy, and allows an estimate of the current velocity error.
The four beams of Origin 65 are equally spaced in azimuth, all with a 20-degree Janus angle and a ±2-degree beam width.
Contact [email protected] for more information.
Origin 600 has an integrated acoustic modem as standard, which facilitates remote communications when using an accompanying topside modem (sold separately) and the Origin Topside PC software.
Origin 600 ADCP has an MF (20-34 kHz) acoustic modem, so users with an MF topside modem, such as a Modem 6 Nano or HPT USBL system, can communicate with a deployed Origin 600 as if it were cabled to a PC or laptop.
Just install the Origin Topside software, connect your topside modem to your laptop, and wake up the ADCP to be able to communicate with your Origin 600.
The integrated modem is 6G compatible, so can work with Sonardyne 6G topside modems, including dunkers and USBL transceivers.
For more information check out the Sonardyne 6G topside modems, and find out about the benefits of remote communications using Origin 600’s integrated acoustic modem.
Contact [email protected] for more information.
Origin ADCPs have an integrated acoustic modem as standard, enabling communication with your ADCP once deployed. This presents a number of operational possibilities and advantages, delivering in-field flexibility and data assurance.
A major limitation of seabed ADCP deployments
Seabed mounted ADCPs have historically been deployed as standalone instruments: The device is pre-programmed with a measurement schedule which allows the ADCP to capture and log water currents at specified time intervals. Once the device has been deployed, it may be months or years until it is recovered, and only then can the data be downloaded and inspected. At best, this results in learning the outcome of the measurements a long time after they were taken. In the worst scenario, the device may have been mis-configured or deployed less than optimally, comprising the data, and/or did not capture any data at all.
What solutions are available?
Some steps have been taken to allow a more instantaneous view of the currents by interfacing a separate acoustic modem with the ADCP. For example, this has allowed users to export industry standard PD0 format data to the surface. However, this process is expensive due to the cost of integration, additional subsea cabling, and a substantially larger payload. What’s more, there is risk associated with achieving acoustic communications in this way, including prevention of data transfer via acoustic telemetry due to limited bandwidth.
Cabled operation is another alternative but suffers from additional risk of damage to the cable, electrical noise pickup from mechanically coupled infrastructure, and is unsuitable in some environments such as deep water or dynamic sites.
What is the Sonardyne solution and what are the benefits?
Origin ADCPs have an integrated acoustic modem, enabling remote communications whilst avoiding the issues of a separate modem or cables.
The Origin 600 ADCP has an MF acoustic modem, and users with an MF topside modem, such as a Modem 6 Nano or MF HPT USBL system, can communicate with a deployed Origin 600 as if it were cabled to a PC or laptop. This goes for Origin 65 too, but this device has an LMF acoustic modem so requires an LMF topside modem for acoustic comms, such as an LMF Dunker 6 or HPT 7000L USBL system.
Just install the Origin Topside software, connect your topside modem to your laptop, and wake up your Origin 600 or Origin 65. You can ask the ADCP how much battery it has left, how much disk space is available, and even check the tilts of the device to make sure it’s level before you leave site.
Forget to configure Origin correctly? Don’t worry. You can set its geolocation acoustically, as well as your assumed salinity and speed of sound in water. Not capturing enough data? No problem – you can reconfigure Origin’s measurement schedule to run faster via acoustic commands, using the same interface as the Origin Scheduler software or the Origin Portal Web UI. Or if a collaborator needs you to run a different schedule, have them send you the file produced by Origin Scheduler and upload it to Origin acoustically. Want to upgrade to run Edge applications? You can upgrade your ADCP to do so, and then upload your preferred Edge app – you guessed it – acoustically.
There are numerous ways by which your ADCP can be checked and configured once in the water. But it doesn’t end there… PD0 records can be acoustically harvested from Origin, so you can see if the quality of the data is good. And if you installed an Edge app that is logging data, those log files can be harvested mid-deployment, allowing you to understand the water and make decisions based on the measurements captured so far. This might even provoke an informed change in measurement schedule to give your mission the best chance of success.
Just for good measure, we’ve made the integrated modem 6G compatible, so it will work with a range of existing and future Sonardyne modem technology. Origin also provides a battery reservoir so that even if there is not enough battery to run ADCP measurements, the integrated modem can still be queried and ranged to aid recovery.
Contact [email protected] for more information.
One of the most powerful features of Origin ADCPs is their compatibility with the Sonardyne Edge computing environment.
What is the meaning of Edge computing?
Edge computing refers to data processing close to where the data is generated. In the case of Origin, that means data processing on the device.
What is the purpose and benefit of Edge for the Origin ADCPs?
Edge lets you run data processing applications on Origin that are customised to your needs. This means that while the device is deployed, it will produce the information you are most interested in, rather than bulky raw data that would normally be processed once the device is recovered from the water. You can harvest this data as a file or as a live stream, either through a cabled connection, or Origin’s integrated acoustic modem.
The data processing applications, or ‘apps’, are installed on Origin in the same way you’d install an app on your smartphone. This makes it really easy to change the information produced by the ADCP depending on your application, meaning you can get the right answer, faster.
Even better, you can install a new app on an uncabled device that’s already deployed – with Origin, you can install apps using the integrated acoustic modem – saving time, cost and risk of a device recovery and redeployment.
Some of the apps developed by Sonardyne are already available and include simple background currents, quality metrics, turbulence, and waves, with more on the way. And just for fun, we also have an app called ‘Aidy’ – our Origin chatbot!
For those computer programmers out there, there is also an Edge Software Development Kit (SDK) available for writing your own Edge apps.
To find out more about Edge computing, the SDK and the apps being made available by Sonardyne, check out videos on our YouTube channel.
Contact [email protected] for more information.
Side lobes are ubiquitous in many sensors, including ADCPs, and affect data captured. Therefore, they are an important consideration when interpreting ADCP data.
What is a Side lobe?
ADCP transducers are designed to be directional, that is, sensitive to water velocities in a specific direction. This direction is called the ‘main lobe’ and its angular extent or beamwidth (in radians) can be approximately calculated in terms of the diameter of the transducer (in metres), and the wavelength of waves transmitted or received by the device (in metres): ∆θ=λ⁄D.
For ADCPs, ∆θ tends to lie in the range of a few degrees.
While the main lobe accounts for most of the sensitivity, a smaller fraction is found in side lobes – directions of sensitivity away from the main lobe. The combination of main lobe and side lobes is called the ‘directivity pattern’ of the sensor.
Simulations of the main lobe and side lobes for the Origin 600 ADCP. The main lobe beamwidth is ±1°, while the first side lobe is located at an angle approximately 3.7° away from the main lobe. The first side lobe (the peak in the pattern closest to the main lobe) is around -18 dB lower power than the main lobe, or about 1.6% compared to the main lobe.
The directionality of the sensor is identical in both transmission and reception. This means that when the ADCP transmits, the amount of power delivered in the direction of the first side lobe is 1.6% of that in the main lobe. Similarly, the strength of a backscattered signal received in the first side lobe would be 1.6% of the power of the same signal received in the main lobe.
The signal received from the transducer consists of contributions from the entire directivity pattern; all directivity information is lost. It is therefore impossible to tell if a backscattered signal came from a weak source in the main lobe or a strong source in a side lobe.
What consideration should be given to side lobes when interpreting Origin data?
The contribution of side lobes is normally so small it is neglected. However, for upward‑facing ADCPs, sidelobes are a problem near the surface where sidelobe pickup from the surface may overwhelm main‑lobe pickup from the water.
When interpreting ADCP data, it is essential to consider contamination by returns from the first side lobe intersecting the surface. In the example below, for a surface return 33 m from the ADCP, the contamination occurs over approximately 2 m beneath the surface, or approximately 6% of the data. This data should therefore not be considered for analysis of water currents.
Backscatter intensity as a function of slant range from Origin 600 data. The water surface is located by the peak in the intensity 31-33 m from the ADCP (in green). Red areas indicate near (left) and far (right) sidelobe contamination.
Contact [email protected] for more information.
With an integrated acoustic modem as standard and the option for Edge data processing functionality, Origin ADCPs have more data retrieval options than standard seabed ADCPs.
As with all standard standalone seabed ADCPs the first data retrieval option for Origin ADCPs is download after device recovery. The Origin Portal Web UI comes with an easy interface for downloading the three core Origin data formats. This of course does have some limitations, namely that data cannot be inspected, and validity confirmed until after the ADCP has been retrieved from the water, risking compromised or even lost data.
Alternatively, with an acoustic modem integrated as standard, data can be offloaded in near real-time when using an accompanying topside modem together with the Origin Topside software. Limited acoustic bandwidth will generally prohibit substantial/full data transfer using this approach, but it is a good option if you are only interested in snippets of information, e.g. individual PD0 records to confirm the ADCP is capturing good quality data.
To maximise the performance of Origin’s acoustic modem in a data retrieval capacity, you can upgrade your Origin ADCP to have Edge data processing functionality. Edge will permit you to upload a data processing app to your Origin ADCP that will not only customise, but also optimise the data the ADCP produces for your particular application. An Edge app can be uploaded to your Origin device, and resulting data packets or files exported in full over the acoustic modem, supporting:
- Near real-time data retrieval and monitoring.
- Post-capture acoustic data harvesting using a USV or buoy.
Both of these options for retrieving relevant data without recovering your Origin ADCP offer benefits. For instance near real-time data offload can support time-critical decision making. Meanwhile, data harvest without the need for an expensive and carbon intensive crewed vessel presents the opportunity for reduced project costs and safety risk.
Contact [email protected] for more information.