seaView V3 provides a cutting-edge user interface for the setup and operation of Impact Subsea sensors including our AUV/ROV Sonar.

AUV/ROV Sonar – seaView Software Introduction

Transcript

Hi! I’m Ben and in this video we’re looking at the ISS360 AUV/ROV Sonar, software application in seaView V3.

When you first run seaView V3 you’ll be presented with this screen here. On the left hand side you have a list of the applications in seaView on the right hand side you have a list of all the communication ports on your computer and in the middle you have a list of any sensors that have been detected.

When seaView is first run it will automatically scan every com port at every known baud rate and will also scan your network to see if there’s any Impact Subsea sensors connected. In this instance it has detected two sensors – we have an ISA500 altimeter and also the ISS360 AUV/ROV Sonar.

The icon for each of these gives a little more detail about the connected sensors for example on the ISS360 AUV/ROV Sonar we can see the serial number the firmware version and also how it’s been connected in this instance we can see it’s been connected over the network and it’s displaying the IP address of the sonar.

Double-clicking on the sonar icon will take you into the ROV sonar app and the sonar will automatically start to scan. In this example we have a sonar running in the Impact Subsea test tank which is roughly a two meter diameter circular test tank and we can see that on screen showing up there.

In the middle of the screen we have the main sonar display on the right hand side, if you have a sonar with integrated pitch and roll, you get the pitch and roll readings and you also get a little graphic of the sonar showing any motion that is experiencing.

We also have a colour chart on the left hand side here so you can change the the colour palette of the sonar to suit your own preference. We typically use this kind of multicolour going from black to blue to green to yellow to red. This bar you can also lift up the lower red rectangle and this will remove all the weaker returns from the display as I move it up you can see only the stronger returns are left on the screen.

As I move it down it’ll start to include the weaker returns as well. Pushing it all the way to bottom means that all the returns will be shown on screen. There’s also a little red rectangle at the top of this this bar if you pull that down it’ll compress the bar and increase the contrast on the screen so pulling it down really far will make a very noisy solar image and really show all the strong returns very vividly and moving it up will decrease the contrast and just show it in its more normal state.

Down at the bottom of the screen we have a gain bar which is currently set to 35. If you increase that it’ll apply more software again to the sonar imagery if you decrease it it’ll remove the gain and essentially you want to set that to a level where you see everything you want to see and you remove any excess noise from the imagery.

The next item down the bottom of the screen is your range setting so you can decrease this to look closer in, down to one meter or you can increase this look further out anywhere up to 100 meters. As we’re working in a two meter tank we’ll just set it down to two meters.

You then have a selector which runs speed to quality and this sets the step size of the ISS360 AUV/ROV Sonar. If we set it to speed the sonar will take a very large step size between pings it will scan round very quickly if we move this bar more towards quality we slowly reduce the step size so it takes finer and finer steps and gives you a finer and finer resolution.

This comes with a trade-off in scanning speed so depending on your application you might want to set it to scan very quickly if you’re moving quickly or navigating underwater and if you get up to a target and you want to identify that target you can move this up to higher quality and get a higher resolution and better understanding of what you’re seeing.

AUV/ROV Sonar Acoustics setup

That’s the basic AUV/ROV Sonar interface, now to go through some of the more advanced features in the top left-hand corner we have a settings button and if you click on settings you’ll be presented with this screen here.

The first settings tab which pops up is your acoustic parameters. Now by default we leave this set to auto. This means as you adjust the range the sonar will automatically update the acoustic parameters to give you the best range and resolution capabilities.

If you don’t want to use this auto feature you can deselect this box and you can edit the start and end frequencies for doing a CHIRP or you could make them both the same if you want to do a continuous wave transmission from the sonar.

You can select the pulse length and also the pulse amplitude but for the majority of applications we recommend this is left to auto and just leave the sonar to determine the best settings for your range setting. You can also set the speed of sound here and you can also invert the sonar image here.

This is quite useful by default the sonar is intended to be run with the black boot end upwards and the connector downwards. If you’re running it the other way up so the boot end down, connector up, click the ‘Invert Sonar Image’ and it’ll just make sure that your your lefts and rights are correct on screen.

AUV/ROV Sonar – Connection

The next setting option we have is your connection, so here you can change the serial mode from RS232 to RS485 or RS485 Terminated and you can also select the baud rate. You can also use this window to set up your your network properties of your IP address, netmask and gateway. You can also enable DHCP if you require this.

Lastly if you have an AUV/ROV Sonar with ARS you’ll have the AHRS settings page. In here you can tell the sonar how it’s been mounted whether it’s the default value whether it’s inverted, whether it’s on its side and this will just ensure that your pitch and roll readings are all accurately referenced you can also input any minor offsets to account for installation error of the sonar.

You can also do a calibration of the magnetometer and select which axis the turns counter counts around whether it’s your Heading your Pitch or your Roll. Once you’ve changed any settings in here as soon as you click the green tick ‘Ok’ button these will be saved to the sonar firmware and those settings will be saved forever more regardless of power cycles.

The only time they’ll get changed is when you go back into seaView, connect to the sonar, make a change and click ‘Ok’ again. If you don’t want to apply the the changes you’ve made just click the the ‘Cancel’ button.

AUV/ROV Sonar – Bins and sector scan

Going back to the other options on the left hand side one is your bins and sector. Bins set to auto basically means it will take a number of samples in each ping to fill every single pixel on screen.

You can then set the AUV/ROV Sonar to a full 360 or you can set it to do a sector scan. Now setting it to a sector scan is very useful if you’re using it on an ROV and you want to look dead ahead or to the side or behind the vehicle and only update that one window.

You can also set the start and stop points of that window so you can narrow it down, you can make it wider it’s totally up to you to how you set that window.

You can also enable flyback. Now if you click on flyback the sonar will scan from the left to the right and then it’ll very quickly fly back scan from the left to the right. If you disable flyback it’ll scan from the left to the right and then it’ll scan from the right to the left so it’s really your preference and how you want the sonar to scan.

At any point you can click the full 360 and we’ll go back to doing a full 360 scan. At any point you can pause the sonar and start the sonar going again. You can reverse the direction of the scan using this button; this is quite useful if you see something moving in the water and you just want to temporarily scan back and forth across that target to track it or see what’s happening there.

AUV/ROV Sonar – Record a log file

You can record a log file if you want to record everything that’s happening for playback later on. You can open it using this button at any point you can clear the screen just to get rid of the historic data and it will start updating the screen again.

You also have a display button and this button can be used to turn on and off different features of the display for example we can turn off the range from the display, you can even turn off the scan line, the grid etc and you can turn things back on like heading around the sensor. You’ve got quite a few few options there.

You also have a reset view here so if you’ve used the mouse or used the zoom buttons here to zoom in and move around the screen to see something more detail you can use this reset button here to put it back to default. You can zoom in zoom out, you can use this feature here to take measurements, so you just click it and then you just click and drag on screen you take any measurements of the sonar imagery.

If you want to measure a target to understand it’s size it’s nice and quick and easy to do that. Again clicking the measurement will turn that off again.

There’s also a feature to add markers on the screen so if you see something of interest you can click on screen add a marker to it using the left mouse button and clicking the right mouse button will take that marker away. You can add multiple markers on screen if you wanted to highlight something to another user or just have them there to reference

That’s the ISS360 application in seaView Software V3, if you have any questions regarding this please do not hesitate to contact us at support@impactsubsea.co.uk

Learn more about how our ROV sonar works in this in-depth technical guide

Take a look at the ISS360 Product Page: ISS360 Imaging Sonar

Watch seaView Software overviews on our other sensors: YouTube playlist

The ISS360 & ISS360HD are compact imaging sonars widely used on underwater Remotely Operated and Autonomous Vehicles. These two sonars are also used in numerous stand-alone applications such as search and recovery.

Sonar Image Quality

A core consideration of any imaging sonar is the quality of the imagery.

For those already familiar with sonar terminology, the ISS360 provides a 2.2° angular resolution (at 700kHz) coupled with a 2.5mm range resolution and a distance measurement range of up to 90 meters/295 feet.   

The ISS360HD provides a 1° angular resolution (at 700kHz) a range resolution of 2.5mm and a distance measurement range of up to 100 meters/328 feet.

To provide further detail of how Range and Angular Resolution influence the image quality: 

Range Resolution

Range Resolution is the ability to distinguish between targets based on distance away from the sonar.  The lower this value the higher the resolution of the image.

Range Resolution is a particularly important factor to consider when working at shorter distances, as it will make a significant difference to the resolution of imagery you see on screen.  At greater distance, small details are missed due to the compression of the imagery on the computer display – so range resolution becomes a less critical factor for general imaging sonar use.

For operation at lower ranges, the ISS360/ISS360HD utilises a CHIRP (Compressed High Intensity Radar Pulse) from 600 to 900kHz. Range resolution of a CHIRP sonar system is equal to the velocity of sound/(bandwidth x 2). This enables a 2.5mm range resolution to be obtained in the ISS360 sonar.

For reference, a 200kHz bandwidth CHIRP would typically provide a 3.75mm range resolution and a 100kHz bandwidth CHIRP would provide a 7.5mm range resolution. 

If you consider a non-CHIRP sonar system which operates by transmitting single frequency pulses, the pulse length dictates range resolution. In a single frequency sonar system Range Resolution is equal to (pulse length x velocity of sound) / 2.  For example a 200μs single frequency pulse will give around a 150mm range resolution, assuming a speed of sound of 1,500 meters per second.

The images below are examples of how range resolution at short ranges compares. The image on the left is a single frequency 200μs pulse (150mm range resolution) and the image on the right is a CHIRP 200μs pulse with 100kHz bandwidth (7.5mm range resolution):

Angular Resolution

Angular Resolution is the ability to distinguish two targets which are at the same physical range away from the sonar (sitting side by side). This is defined by the horizontal acoustic beamwidth of the sonar. 

Angular resolution typically becomes more important as distance increases.  At longer distances the footprint of the acoustic beam will become one of the most influential factors in defining the image clarity.

The ISS360 has an angular resolution of 2.2° which is ideal for many applications.  The ISS360HD has an angular resolution of 1° which provides exceptional image quality.

The illustration below shows the acoustic beam from the ISS360.  This is then stepped 360° around the sonar to provide the full sonar plot.

IS³ Acoustics

In addition to CHIRP acoustic signalling the ISS360 & ISS360HD imaging sonars also benefit from the Impact Subsea Signalling Scheme (IS³).

IS³ uses advanced phase modulation and coding techniques to provide exceptional signal integrity, timing accuracy and range resolution. This scheme can be enabled or disabled within the sonar settings. When enabled, IS³ is used in conjunction with the standard sonar acoustic settings (alongside CHIRP at shorter ranges and single frequencies at longer ranges).

In addition to increasing range resolution, IS³ reduces the interference between multiple ISS360 Imaging Sonars operating in close proximity. This can be highly useful if multiple imaging sonars are in use on the same AUV or ROV.

Other Factors

Range Resolution and Angular Resolution are two of the main parameters used to define sonar image quality.  However there are other factors which come into play.

The acoustic detection method in use can make a large difference to the overall image quality, in terms of image noise level and range capability.  The ISS360 & ISS360HD use a digital correlation technique to detect the returning acoustic pulses. The two sonars do not employ any filtering of the incoming data. All incoming data is processed directly through the digital correlator to ensure no loss of quality.  The complete digital process without degradation of the incoming data is the reason the ISS360 sonar imagery often looks ‘cleaner’ than some alternative sonars of a comparable angular resolution.

There are also other elements affecting the displayed image, the quality of the electronic analogue front end design, transmit power, CHIRP implementation, detection algorithm, transducer design etc which will be unique to each sonar manufacturer.

The technical specification of a sonar system will provide a reasonable appreciation of what to expect from a sonar in terms of its capability. To take all possible factors into account however, study of the actual sonar imagery produced should be undertaken.  

Example imagery from the ISS360 & ISS360HD range of sonars can be found on the ISS360 page here.

Scanning Speed

In a perfect mechanically scanning sonar, scanning speed should only be limited by the travel time of the acoustic pulse (journey from sonar to maximum range and back again). 

The ISS360 & ISS360HD Sonars comes very close to this theoretical maximum scanning speed. This is achieved through two factors:

Ethernet Comms

In addition to Serial communications capabilities, RS232 and RS485, the ISS360 & ISS360HD also come with Ethernet communications capability as standard. This provides a high bandwidth communications channel which does not restrict the scanning speed of the sonar.

Processing Power

An advanced digital correlation technique is employed to detect the returning acoustic waveform. This correlator is run exceptionally fast utilising the ISS360/ISS360HD’s powerful internal processor.  

The high processing speed of the ISS360/ISS360HD’s hardware combined with the unrestricted communications path enables a very fast scanning speed.  This is particularly noticeable at lower ranges where processing power is critical. 

In third party benchmark testing against other popular scanning sonars in the market, the ISS360 was found to scan up to six times faster at shorter ranges.

For those using the sonar for the purpose of obstacle avoidance operations, this is a significant step forward from what was previously available.  For many applications the increased scanning speed negates the requirement to utilise a multibeam sonar for obstacle avoidance purposes. 

The video below shows the scanning speed of the ISS360 Sonar when operating over Ethernet communications. Low to high scanning resolutions are shown: 

Size & Weight

The ISS360 was developed to be the most compact, mechanically scanned imaging sonar in the world.

Highly compact with a weight of 0.37kg/0.82lbs in air ensures that the ISS360 is exceptionally easy to integrate onto all underwater vehicles – from observation to work class. The ISS360HD is slightly heavier at 0.76kg/1.675lbs in air.

Due to the use of the latest electronics and advanced digital acoustic engine, the compact sonar size has not compromised performance.  With the highly compact ISS360 and ISS360HD outperforming sonars which are many times its size. 

Reliability

The ISS360/ISS360HD benefits from an inductively coupled transducer.  This means there are no slip rings within the sonar so there are no components to wear out and require periodic replacement. 

The body is titanium, which provides an extremely robust and long lasting housing. The use of titanium instead of anodised aluminium ensures that the housing will not need to be periodically replaced.

The ISS360/ISS360HD also benefits from a fused comms lines, undervoltage protection and reverse voltage protection.

The above features enable a sonar which is very long lasting and highly resilient in tough environments. 

Software

The ISS360/ISS360HD operates with the Impact Subsea seaView V3 software, allowing seamless use alongside the Impact Subsea Altimeter, Depth Sensor, AHRS sensor, Profiling Sonars and FMD System.

A full overview of the ISS360/ISS360HD Sonar application within the seaView V3 software can be viewed below: 

For those wishing to use the ISS360/ISS360HD with an autonomous underwater vehicle, a Software Development Kit (SDK) is freely available to allow direct integration of the sonar. The SDK can be accessed on Github here. There is also an example project here.

Shown below is a seaView software screen, displaying the ISS360 Sonar operating alongside the Impact Subsea Depth Sensor, Altimeter and AHRS sensor:

Attitude Reference System

The ISS360/ISS360HD is optionally available with an in-built Attitude Reference System (ARS).  This provides Pitch and Roll as a viewable output.

Aside from a useful additional measurement parameter, the ARS can also be used to ensure that the ISS360/ISS360HD is perfectly level during standalone operation.  This will ensure that the maximum range is achieved in all directions around the sonar.

Physical Configuration

To ensure the ISS360/ISS360 is simple to integrate into any Autonomous Surface Vehicle (ASV), Autonomous Underwater Vehicle (AUV) or Remotely Operated Vehicle (ROV) the ISS360 is available in two configurations:

The ISS360HD is also available in two configurations:

Overall

The ISS360/ISS360HD series of imaging sonars provide excellent image quality and fast scanning speed. Presented in a compact and robust form factor makes the ISS360/ISS360HD ideal for a multitude of underwater applications.

If you would like to discuss the ISS360/ISS360HD in more detail, and how it can be used in your underwater application, please drop us an email at sales@impactsubsea.co.uk

Or alternatively, call us on +44 1224 460 850

The latest ISS360/ISS360HD Imaging Sonar datasheet, manual, 3D models and further technical information can be found on the product page

Watch and learn more about the ISS360/ISS360HD Imaging Sonar: YouTube playlist

Scour monitoring is the process of measuring how flowing water erodes the bed around underwater structures, so that damage can be found before it threatens the structure.

This guide draws on a peer-reviewed study by the University of Twente using the Impact Subsea ISS360 Imaging Sonar.

What is scour monitoring?

Scour monitoring means tracking how water flow removes sediment and protective material from the bed around a structure such as a lock, quay wall or bridge pier. Because scour develops over time, repeated or continuous measurement lets asset owners see whether the bed protection is still doing its job and plan maintenance before the structure’s foundations are at risk.

Why does scour happen at navigation locks?

At navigation locks, scour is driven by river flow and by currents from ships: propeller wash, bow thrusters, and the water released when lock chambers are filled and emptied. Many locks were built for smaller vessels than the ones using them today, so the bed is under more strain than it was designed for.

There are three main risks:

• Scour holes: that undermine the bed protection and eventually, the structure itself.
• Rolling stones: rocks displaced from the bed protection that end up in the lock. Obstructions like these can stop gates from closing and damage components such as de-icing pipes.
• Shallow under-keel clearance: Rijkswaterstaat guidance recommends a water depth of 1.4 times a ship’s draft. For the 4 m-draft vessels the lock’s newest chamber was built for, that means 5.6 m, and the researchers found the Prinses Beatrix Lock doesn’t meet it. Loaded and unloaded ships can also differ in draft by up to 2 m, so knowing how deep each vessel actually sits matters.

What are the stages of scour?

Scour research typically describes three stages in how a local scour hole develops:

Because scour depends on time, the University of Twente researchers describe continuous monitoring of scour-prone areas as crucial.

Why is visual inspection difficult?

Diver inspections and bathymetric surveys give valuable detail but they are costly, only capture moments in time and are limited by turbidity: in murky inland water, a diver or camera may barely see the bed. Changes caused by a single ship passage can happen and go unnoticed between inspections.

How does a 2D imaging sonar detect bed changes?

An imaging sonar builds a picture of the bed from sound rather than light, so turbidity doesn’t stop it. When it’s fixed in place, it scans the same area over and over. At the Prinses Beatrix Lock, an image was saved every minute and divided into small regions of interest.

Each region was compared with the same region in later images. Rock pieces show up as bright spots, and their stable pattern acts as a “fingerprint” of the bed protection. When the pattern changes, material has moved.

Can sonar detect loose stones in a lock?

Yes. The sonar tracked stones on the lock chamber’s concrete floor, and one persistent bright spot was confirmed by an underwater drone to be a substantial rock. Spots that appeared briefly were put down to fish or light objects, while spots that stayed for more than an hour pointed to heavier objects. Stones could be detected at a range of 30 m.

Can sonar measure a ship’s draft?

It can indicate it. With the ISS360 tilted 90°, a passing hull blocks the sonar’s sound and shows up as a strong reflection. How far that reflection extends towards the bed indicates the ship’s draft and under-keel clearance. In this setup the sonar sat at about 3.5 m depth, so drafts beyond that couldn’t be resolved. The study didn’t report accuracy figures.

Case study: the Prinses Beatrix Lock, Netherlands

The Prinses Beatrix Lock on the Lekkanaal, which links the Lek River and the Amsterdam-Rhine Canal, is the largest monumental inland navigation complex in the Netherlands. Around 50,000 vessels pass through it each year. Diver reports and point cloud data had already shown degradation of the bed protection, along with a scour hole near one chamber.

Researchers Mohsen Bastani and Rolands Kromanis of the SHM4SI research team at University of Twente, scored 12 commercial 2D sonars and selected the ISS360. They mounted it on a 6 m steel pipe clamped to the lock’s fendering timbers, behind the fender wood so it stayed clear of passing ships. Their paper, “2D sonar techniques for monitoring the canal bed morphology of entrances to navigation locks”, won best paper at SHMII-13.

Key findings:

• Bed changes caught as they happened. Over 7 days of scanning, the system detected a 0.5 m² stone shifting within one minute of a ship passage. That met the project’s requirement to capture changes of 0.5 m² or more within 3 minutes.
• Weak areas identified. Some areas kept a stable pattern for days, then rearranged after a ship passed. That points to loose stones or sand-filled voids in the protection layer.
• Ship passages linked to degradation. Matching sonar images to specific passages gave evidence of which ships were displacing stones. In 50 hours of draft measurement, 22 passages had drafts over 3 m.

Limitations and next steps: a 2D sonar can’t capture vertical faces (which is why it was tilted for draft measurement), its field of view makes it hard to trace where stones came from, and the dataset was small. The researchers recommend at least six months of continuous data, extending monitoring to the other chambers and automated detection that links bed changes to individual ship passages.

“Imaging sonar is usually thought of as a vehicle sensor. This study shows it can also be a permanent monitoring sensor, fixed in place and watching a critical asset in conditions where nobody could see.”

Ben Grant, Managing Director, Impact Subsea.

Download the case study | Read the paper | Learn about the ISS360 Imaging Sonar | Read the news announcement

Why the ISS360 suits fixed monitoring

The ISS360 is a compact scanning imaging sonar, just 47 mm in diameter, with a 360° field of view, a range of up to 90 m and a 6,000 m depth rating. In the study it ran on 24 V DC, drawing 150 mA while scanning. Its small size made it straightforward to mount on existing lock structures.

Frequently asked questions

Want to talk about scour monitoring for your site? Contact our team or email info@impactsubsea.co.uk.

seaView Software V3 provides a cutting-edge user interface for the setup and operation of Impact Subsea sensors.

Transcript

Hi! I’m Ben and in this video we’ll be looking at the ISA500 application in seaView software V3.

When you first run seaView software you’ll be presented with this window here.  On the left hand side. You have a list of applications within seaView software. On the right hand side you have a list of all communication ports and network connections on your pc. When you first run seaView software it will automatically scan all communication ports at every known baud rate. It will then automatically detect any sensors connected to your computer.

In this example two sensors have been detected, one is the ISS360 Sonar and the other is the ISA500 Altimeter, as shown in the center of the screen. If you look at the icon for the ISA500 Altimeter, you’ll find you’re given a little bit more information such as the serial number of the sensor, the firmware version and also how it’s connected to the software. In this particular example we can see it’s connected via COM Port 5 at a baud rate of 115,200. If you double click on the ISA500 icon you’ll be taken into the ISA500 application.

seaView Software Application main screen

Now in the application, the top left hand corner shows the distance reading being reported by the ISA500. Every time the sensor pings you will see a green flash of this light here and a distance reading reported. Below the distance reading you also get an energy and correlation value. Also reported is the temperature of the ISA500 internal electronics and if you have an ISA500 with integrated Heading, Pitch and Roll, you’ll also get Heading, Pitch and Roll readings with a little 3D model of the sensor to show you how it’s orientated at any one time.   

Acoustics settings

In the middle of the screen you’ve got a graph showing distance measurements over time. The left hand side of the screen you have a number of icons. Now if we start with the top icon, this is the ISA500 settings, so if you enter the settings you’ll be presented with a window like this. The first settings window is all to do with the ISA500 Acoustics.  

The ISA500 is a highly configurable altimeter. You can configure many parameters; for example you can change the detection mode you can operate in first detect, strongest or seabed tracking. First detection mode is ideal if you’re working in a confined space where there’s a lot of multi-path, multi-echo capability such as inside a tank. Strongest echo is better for open water activity and if you’re wanting to track the seabed then there’s a seabed tracking option as well.

You can also enable and disable tilt correction, so if you have an ISA500 with integrated AHRS, enabling tilt correction will automatically convert slant ranges into actual altitude so it’ll correct for pitch and roll of your vehicle and give you a more stable altitude reading. You can disable this if you wish and just have pure range readings from the sensor.

You can then configure minimum and maximum ranges, so for your minimum range anything below the set value will never be detected by the ISA500 and your maximum range anything above that value will never be detected by the ISA500 so you can basically gate the ranges that you’re wanting the sensor to look over.  

You can also set the frequency. The ISA500 is a broadband altimeter so you can run it anywhere from 400 to 600kHz. You can set the speed of sound to give you an accurate distance reading, you can set the pulse length and the pulse amplitude. You can also put in any distance offsets as required. Moving on to the next settings window the analogue output.

Analogue output

The ISA500 can provide you a serial ASCII output but it can also provide you a scaled output and it can provide a scaled current or it can provide a scaled voltage and you can set up the scaling. So you can set up the start and stop voltages and your minimum and maximum ranges to scale that over.

Echoes

The next setting option is your multiecho setup and this is the number of echoes to be reported on from a single ping. Most applications the ISA500 is used just to give a single range reading but it can also give you multiple range readings from a single ping and you can set how many range readings you want the sensor to report on.

Connection

The next option is your connection so in this window here you can select the serial mode which  can be RS232, RS485 or RS485 terminated. You can also set the required baud rate together with the word length, parity and the number of stop bits required.

Output string

The next option is the output string. This is the output string for the distance reading. There’s a number of pre-configured strings and all of which are detailed in the ISA500 manual so you’ve got a number of Impact Subsea strings and you have a number of third-party strings to allow the ISA500 to emulate other altimeters in the market. If the particular string you require is not there you also have the custom button which allows you to create your own ASCII output string in the exact format which you require.

You can also set up in this window what the ISA500 should do if no returns are received whether it outputs a zero reading or a maximum reading and you can also tell it how many times you want it to ping an output to reading anywhere from well a fraction of a second up to up to 100Hz.

You can also set up the interrogation method so if you want to interrogate the ISA500 and command it to ping you can enable that and also set the parameter for it to respond to. You can also select interrogate via TTL if you want to trigger it via TTL and you can select whether it’s the falling edge or the rising edge of the TTL pulse which it triggers on.

AHRS settings

Then if you have an ISA500 which has integrated AHRS you’ll have the AHRS settings option. In here you can configure everything to do with the Heading Pitch and Roll. To start off with you can select the orientation, by default it’s assumed that the ISA500 has the connector pointing upwards and the transducer pointing downwards, however you can change it to be inverted or pitched over or rolled over. And these just set the reference point for your your Pitch, Roll and Heading to make sure you get accurate readings.  

Once installed on the vehicle if there’s any inaccuracies and how it’s been installed you can apply minor offsets to the heading pitch and roll. You can also apply a magnetic declination offset enable inertial mode, calibrate the magnetometers and set up your turns counter for the sensor as well.

AHRS output string

The last option to look at here is your AHRS output so this configures the ASCII output string for the heading pitch and roll side of things. And as before the number of Impact Subsea strings and there’s a number of industry standard strings as well. All of which are documented in the ISA500 manual and again as before if there’s a string you require which isn’t there or you want a slightly different string you have the custom option to go in edit a string or create an entirely new string to meet exactly what you require.

Like the altitude or range output you can select how many times per second the string is output. You can also enable interrogation and set up the parameter for the ISA500 to respond to and you can also have the output output on a TTL interrogation as well so that’s all the core ISA500 settings so if we return to the main screen.

If we look at the left hand side again there’s a ping button so you can manually trigger a ping from the sensor and there’s also a ping rate and this sets the ping rate of the sensor when it’s connected to the seaview software so it’s currently set to 1Hz.

We can increase it to 5Hz or 10Hz or we can set the sensor to run at maximum rate. If we set to maximum it’ll basically ping as fast as it can given your minimum maximum range setting. And as we change the ping rate you can see that green light flashes at the designated rate and that basically flashes once per ping on the sensor.

Record log file

At any time you can enable a log file by clicking here and it will record all the ISA500 readings to a log file and time stamp them. You can clear the graph data here if you want to start afresh. You’ve got display options so you can set exactly which parameters you want to be showing on screen. For example you could turn off the temperature we turn off the heading pitch and roll so you’ve just got altitude in the little 3D model for the ISA500, or you can enable all those back on again. Turn on the turns counter, so it will show you the number of turns the ISA500 has made.

Multi-echo output

And the last item I’ll show you here is the multi-echo output capability. If you click show multi-echo it’ll bring up another graph at the bottom of the screen. You can click and make this graph a bit larger and this graph will essentially show you every single return that ISA500 sees from a single pulse being sent out. It gives you a good appreciation of exactly the acoustic environment in which ISA500 finds itself. Or if you want to make multiple measurements to different targets that fall within the six degree conical beam from the ISA500, this is a good way to do it.

Multi-echo output

And the last item I’ll show you here is the multi-echo output capability. If you click show multi-echo it’ll bring up another graph at the bottom of the screen. You can click and make this graph a bit larger and this graph will essentially show you every single return that ISA500 sees from a single pulse being sent out. It gives you a good appreciation of exactly the acoustic environment in which ISA500 finds itself. Or if you want to make multiple measurements to different targets that fall within the six degree conical beam from the ISA500, this is a good way to do it.

ECHOGRAM

Since the above video was created, a new feature was added to seaView. For ISA500 sensors with ECHOGRAM enabled, the ECHOGRAM graph can be shown.

This provides full sonar backscatter data (up to 2,000 samples per ping). A full technical overview of ECHOGRAM can be found here.

Graph options

One other item to consider, on the right hand side of the screen we have a graph options button and this allows you to edit the graph display so you can turn off the fill and you can have it draw points for every ping, can turn off draw lines you can basically alter things to get the exact graph that you want to have on screen.

That’s the ISA500 application in seaView Software V3, if you have any questions regarding this please do not hesitate to contact us at support@impactsubsea.co.uk

Take a look at the ISA500 Product Page: ISA500 Altimeter

Learn more about how our altimeter works in this in-depth technical guide

Watch seaView Software overviews on our other sensors: YouTube playlist

The ISA200 & ISA500 are widely used as underwater Altimeters on Remotely Operated and Autonomous Underwater Vehicles.  The sensors are also used as high accuracy underwater ranging devices, providing distance measurement to any target aimed at.

Measurement Range:

A critical consideration when choosing an underwater Altimeter is how far away will it be able to detect the seabed (or other target) from.

The use of a digital correlation echo detection technique combined with a highly sensitive composite transducer enable the ISA500 to provide market leading range performance from a 500kHz frequency Altimeter.

The ISA500 is characterised as having a range capability in excess of 120 meters / 393 feet.  The ISA200 has a range in excess of 250 meters / 820 feet.

Both sensors operate on sonar technology – they transmit a pulse of sound and time how long it takes for the sound to return.  Based on the time taken, it calculates the distance travelled by the sound and derives the range to target.

The overall range capability will largely depend on the acoustic reflectivity of the item it is pointed at.  For example, if pointed at a seabed with a large amount of marine growth on the surface,  a reasonable proportion of the pulse of sound will be absorbed.  In which case a range of 80 meters/ 262 feet or less may be achievable with the ISA500. On the other hand, if the seabed has a strong reflector, such as solid rock, ranges in excess of 175 meters / 575 feet can be achieved with the ISA500.

The sensitivity of the ISA200 and ISA500 ensures that the longest range possible for the environment it is operating in can be achieved. 

Measurement Accuracy:

For many applications, accuracy and repeatability of the distance measurement are highly critical.

As mentioned previously, the ISA200 & ISA500 use an advanced digital correlation technique to detect the reflected pulse of sound.  This digital correlation is run 2,000,000 times per second.  This gives the ISA200 & ISA500 an accuracy level of 0.7mm which is then rounded up to the nearest 1mm.

This allows the ISA200 & ISA500 to provide 1mm accuracy and repeatability in range measurements.  This introduces the sensor to applications where previously only technologies such as a laser-based measurement systems would suffice.

A critical point to appreciate is that the ISA200/ISA500 offers 1mm accuracy as well as resolution.

When defining the capability of an Altimeter, it is important to recognise the difference between resolution and accuracy. A number of alternative Altimeters are quoted as having ‘1mm resolution’ which in itself is a relatively meaningless statement unless the Altimeter also has 1mm accuracy.  Otherwise, the sensor is simply providing centimetre level of accuracy to 1mm precision.

When choosing an Altimeter, one should always check what the measurement accuracy is – not just the resolution.

The below is a short example of the ISA500 achieving 1mm accuracy in distance measurement over a 1 meter range: 

Measurement Quality:

A key question with every reading from an underwater Altimeter is: how trustworthy is the reading which has been made?

In addition to the distance measurement value, a number of serial output strings from the ISA200/ISA500 also report back the energy level of the echo and a correlation factor.

The energy level ranges from 0 to 1, where 1 represents full saturation of the ISA200/ISA500 receiver. An energy level of 0.707 (square root of 2) is the theoretical perfect level as it represents the energy of a pure sine wave with an amplitude utilising the maximum dynamic range of the ISA200/ISA500.

The correlation factor ranges from 0 to 1, which represents a quality factor of the returned echo. A value of 1 would represent a return echo of perfection with negligible noise and distortion.  

The correlation value alone can be used as a trust factor where low values such as 0.3 would indicate that a reading is likely incorrect.  In practice, ISA200/ISA500 sensors are pre-set to ignore all returning echoes with a correlation level below 0.5.  This ensures every reading produced by the sensor is of a high quality level. 

A more detailed picture can be built by combining this information with the energy level as shown in the table:

With energy and correlation values, the quality of the distance reading provided by the ISA200/ISA500 is always clear. 

Acoustic Bandwidth:

The ISA500 can be operated at any frequency from 400 to 600kHz.  The performance across this bandwidth is relatively uniform, with a slight increase in performance at the 500kHz point.

The available bandwidth allows for multiple ISA500 sensors to be operated in close proximity, all at slightly offset operational frequencies.  This ensures that there is no interference between sensors.

The available bandwidth also allows for the sensor to be adjusted to another frequency to move it out of band of other acoustic devices in operation (Sonars, Profilers, DVLs etc).  Thus, ensuring there is no interference with third party systems.

ISA200/ISA500 Altimeter Interfacing:

The ISA200/ISA500 comes as standard with both RS232 and RS485 serial interfaces integrated into the sensor. 

The sensor can run directly into Impact Subsea’s seaView software or it can output any number of ASCII strings for integration into third party systems.  This includes proprietary Impact Subsea strings, but also the ability to emulate any other underwater Altimeter – making the ISA200/ISA500 a very simple sensor to retrofit to existing systems.

In addition, the ISA200/ISA500 has a voltage and current analogue output as standard which can be scaled across a user defined distance and output voltage/current.

ISA200 & ISA500 Altimeter Software Configuration:

One of the key benefits of the ISA200/ISA500 Altimeter is that all settings are entirely software configurable.  There is never a requirement to open the sensor – all settings can be adjusted using the freely available seaView software.

From an acoustic perspective: the detection mode, minimum and maximum ranges, pulse length, operational frequency etc., can all be altered to allow the ISA200/ISA500 to achieve the best performance possible in the application to hand.

The communications mode, output strings, update rate etc., can all also be configured using the seaView software and then saved to the sensors firmware.

The below video provides an overview of the ISA200/ISA500 application showing where all the core elements of the user interface are and highlights the settings available on the ISA200/ISA500 sensor itself.

Multi-Echo:

Most underwater Altimeters will output a single distance reading.  The ISA200/ISA500 can do this, however it also has the option to output the distance reading of every echo that is returned to the sensor.  This allows multiple targets to be tracked within the acoustic beamwidth of a single ISA200/ISA500.

Detection Mode:

The ISA200/ISA500 Altimeter has several detection modes available to select which returning echo is used when calculating the distance measurement.  

‘First’ detection mode will use the very first echo to be returned.  This mode is ideal for use in high multi-path environments such as water tanks.  Once the first echo has been returned, all other echoes will be ignored. 

‘Strongest’ detection mode will use the strongest (highest amplitude) echo returned.  In this mode smaller echoes will be ignored and only the largest reflected echo from the seabed used.  This provides very stable range measurements, especially helpful in applications with a large amount of suspended sediment (such as trenching). 

‘Seabed Tracking’ will use an algorithm to determine where the seabed is and will operate to track this range, ignoring any obviously incorrect readings. 

Echogram:

Optionally available on the ISA200/ISA500 is ECHOGRAM. This new feature adds a full backscatter capability to the ISa200/ISA500, enabling the underwater Altimeter to be upgraded to have a full single beam imaging sonar capability.

Underwater Altimeters typically provide only a single range reading per ping. However, with the addition of ECHOGRAM, the water column and seabed can be fully visualized, allowing for visual identification of targets. This provides up to 2,000 samples per ping, with each sample representing the correlation level of acoustic signal return at its particular point in the range.

Attitude & Heading Reference System:

The ISA200/ISA500 is optionally available with an in-built Attitude and Heading Reference System (AHRS).  This provides Heading, Pitch and Roll as a secondary output.

Aside from a useful additional measurement parameter, the AHRS can also be used internally within the ISA200/ISA500 to correct for Pitch and Roll.

Usually if the vehicle or asset which the Altimeter is mounted pitches or rolls, this causes the Altimeter to measure slant ranges and will make the Altitude reading rise up and down, despite there being no actual change in Altitude.  The AHRS can be used to correct for the pitch/roll by changing the slant range measurement into actual altitude through basic trigonometry.

This ability can be turned on and off in the ISA200/ISA500 settings.

ISA200 Altimeter – Physical Configuration:

Detailed chart of options available when purchasing an underwater altimeter

ISA500 Altimeter – Physical Configuration:

To ensure the ISA200/ISA500 is simple to integrate into any application, a variety of physical configurations exist. The ISA200/ISA500 is available in Titanium or Acetal materials, both used due to their longevity. 

The ISA200/ISA500 is also available in a forward looking or right angled housing and to a variety of depth ratings from 1,000 meters to 6,000 meters.  The ISA500 is also available to a depth rating of 11,000 meters. 

Alternative OEM options are also available for direct integration into your own housing if required.

For example, the Acetal Right Angled ISA500 sensors are a popular choice to use in towed Magnetometers.  OEM options are useful for small compact AUVs. The Titanium Forward Looking ISA200/ISA500 sensors are a popular choice for medium and workclass remotely operated vehicles. 

Robustness: 

The ISA200/ISA500 Altimeter has been designed and built with the highest levels of longevity and robustness in mind.

As already highlighted, the housing materials used are either Acetal or Titanium, chosen due to their longevity and strength.

The electronics are of commercial grade and are of single board design.  All components are low mass to ensure excellent shock and vibration performance.  No screws are used within the design, with a snap and lock together methodology being used to ensure no parts can come loose over time.  

The ISA200/ISA500 sensor has undergone vigorous environmental testing. This includes vibration, shock and thermal testing to meet the stringent requirements of API 17F qualification.

Overall:

The ISA200/ISA500 Altimeter/Echosounder/Ranger provides a long-range underwater measurement capability combined with a high level of accuracy.  

The ability to configure all aspects of the sensor via software enables the sensor to be easily tuned to suit the application at hand.

A robust design ensures that the ISA200/ISA500 is suitable for the most challenging of environments. 

If you would like to discuss the ISA2000 or ISA500 in more detail, and how it can be used in your underwater application, please drop us an email at support@impactsubsea.co.uk

Or alternatively, call us on +44 1224 460 850

The latest ISA200 and ISA500 Altimeter datasheet, manual, 3D models and further technical information can be found on the product page

Watch and learn more about the ISA200 & ISA500 Altimeter: YouTube playlist

ISA500 – ECHOGRAM Transcript

Hi I’m Ben, Managing Director of Impact Subsea and today we’re looking at the ISA500 – ECHOGRAM feature within the ISA500.

Now when you run seaView V3, you’ll be presented with a screen very similar to this one and when you connect your ISA500 to seaView it’ll show up as a tile here. Double clicking on the ISA500 will bring up the ISA500 application.

Within the ISA500 application you’ve got your distance reading, the top left hand corner you’ve got the temperature of the sensor itself, inside the sensor. If you have AHRS enabled in the ISA500 you’ll also have heading, pitch and roll and a 3D model shown on screen. These values will update as the ISA500 is moved so if we move the ISA500 in real time you can see the heading, pitch and roll change along with the 3D model. We also have a turns counter on screen which will count the number of turns of the ISA500 about a specified axis. Below that we have a a graph of distance over time on the screen.

ISA500 – ECHOGRAM Capability

For those with an ISA500 – ECHOGRAM capability; if you navigate to the left hand side of the screen, click on ‘Show Echogram’ if you click on ‘Show Echogram’ it’ll bring up the ISA500 – ECHOGRAM graph and we can adjust the value of that graph.

I’ll just adjust it so its full size on screen just now and what we’re seeing being presented on screen is a graph slowly building up. Now at the moment the ISA500 is set to ping at just 1 Herz so doing one ping per second so the graph is quite slowly building up.

Ping Rate

We can adjust the ping rate of the ISA500. On the left hand side here there’s a ping interval button. If you click that you can select how many times a second the ISA500 should ping. You can select anywhere from 1 Herz to 10 Hertz & maximum. The maximum rate you can ping at will be dependent on the range at which the ISA500 is set over and also the bandwidth of your serial communications. For now we’ll set it to maximum so we’ll get it pinging as quickly as we can so we can see a graph building up a lot quicker on screen just now.

Demonstration in Test Tank

At the moment the ISA500 is just in our test tank behind me here and it’s sitting statically at a set height so we’re just getting quite a a flat line. If we take the ISA500 and move it in the water a little bit and lower it down you can see the the graph representing the lowering of the ISA500, if we rise it back up again you can see the is ISA500 coming back up on screen there. You move it up and down you’ll get a nice sinusoidal graph showing there and again if you just tie it off so it’s sitting there statically you get a flat line again.

Graph Display

On the left hand side you can adjust the the colour of the ISA500 – ECHOGRAM data so we’re using the multicoloured chart just now but you can also use a gold palette or a more blue palette. I’ll leave it on the multicoloured chart for the rest of the demo.

On that graph there you can also adjust the red box, lower part of the colour chart. That is a threshold so if you bring that up it’ll remove the weaker returns and only show you the stronger returns on screen. You bring it down, it’ll show you more and bring it right down to the bottom, it’ll show you every single return there. You can also move the tab at the top this acts as a compression on the color chart and it’ll increase the contrast on screen so you bring that down quite a lot, get a higher contrast image.

Samples Per Ping

On the right hand side of the software application you’ll find an ‘Echogram options’ button. If you click this it’ll bring up a few other options you can tweak. One is the number of lines on the X axis. If this is set to ‘Auto’ it’ll lock the number of lines in the X axis. The number of pixels on screen, in this case 1,492.

The ISA500 has the capability of outputting up to 2,000 samples per ping. That’s the the maximum number you can show on screen at one time. You can disable the auto feature and you can put in a set number of lines or samples to be returned. We can set that to any value from 0 to 2,000 that we want or we put it back to ‘Auto’ it’ll just lock it to the pixels on screen again.

ISA500 – ECHOGRAM Options

There’s a gain here which is purely a software gain so this will adjust the data which is on screen so you may want to tweak this. Turn it up if you’re looking for weaker echoes so you can see them more clearly.

You can also invert the Y axis you can blank the minimum range. If that’s turned off you’ll see the transmission burst of acoustic energy in the ISA500. You turn that on, it just blanks that out so you don’t need to see it.

If smoothing is turned on it’ll give a little bit of interpolation between each ping and just give the data a nicer smoother look. You can also turn on and off the the colour palette if you don’t want to have that showing on the screen.

Demonstration in Test Tank

I’ll just give a quick demo, so if we move it up to the highest point you can see the graph there showing a high reading, if we slowly lower it down, you can see that going down there. You can see most of the turns are quite red because we’re getting quite a high energy return off the base of our tank.

If you’re doing this in open water, if you had a stony kind of seabed, you’ll get quite high energy returns. If it’s sand, slightly less energy, if it’s covered in marine growth gets less energy still.

The benefit of ISA500 – ECHOGRAM is you’ll be able to see the marine growth sitting on top of the seabed.

If you wanted a full overview of the ISA500 application, including all ISA500 acoustic settings, check out our ISA500 overview video.

Thank you.

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To help break it down, we’ve compared our two industry-leading subsea altimeters and echosounders head-to-head: The Impact Subsea ISA200 (Long Range) and the ISA500 (Precision).

ISA200 and ISA500 – Which one should you choose?

Our ISA200 and ISA500 both deliver 1mm accuracy, with optional AHRS for Heading, Pitch & Roll and ECHOGRAM capability for sonar backscatter.

ISA200 – Long Range

• 250m+ range
• 15.2° conical beam
• 200kHz operation
• Best for: Applications where maximum range and altitude tracking at a distance are the priority.

ISA500 – Precision

• 120m+ range
• Narrow 6° conical beam
• 400–600kHz acoustic frequency
• Best for: Projects demanding high-resolution precision measurements in tighter beam constraints.

Both can be used across a wide range of subsea applications, including ROV & AUV altitude, heading & attitude measurement, hydrographic survey, equipment deployment, distance measurement and scour monitoring.

Compare full technical specifications of our subsea altimeter & echosounder range

Our latest seaView software overview film features Ben Grant, Managing Director of Impact Subsea, providing a comprehensive guide to setting up your sensor system for ROV operations.

Ben demonstrates how to configure the newly launched seaMux ROV Multiplexer and Unity Topside Control System using seaView Software.

The guide covers how to automatically detect and configure devices within the seaView interface, as well as how to use the software to power sensors directly through the system and configure individual communications ports for RS232, RS485 or Ethernet.

Additionally, the video explains how to bridge data from subsea sensors to topside systems, including passing third-party serial data through the network and how to utilise the built-in monitor tab to track raw data and verify data routing across the entire system.

Whether you’re performing ROV integration or survey suite configuration, Unity & seaMux are designed to provide a robust and high-performance solution to your complex sensor networking.

ROV Multiplexer, seaMux & Control System, Unity – seaView Software Overview Film Transcript

Hi, this video covers the seaView overview of the seaMux subsea ROV multiplexer and the Unity topside control system.

Of note, in order to utilise Unity and seaMux, you’ll need to have seaView 3.2 or newer in order to detect these devices.

For the purposes of demonstration, this overview is conducted on a Unity topside control system connected to a seaMux subsea ROV multiplexer.

If you’re using a seaMux subsea multiplexer on its own, everything will be much the same except you won’t have the Unity portions of this video.

seaView at a glance

So to start things off, when you first turn on Unity, after a minute, it’ll boot into its operating system and it’ll automatically run seaView.

At that point, it’ll find itself and if you have seaMux connected, it’ll automatically detect that. Any sensors connected are shown in this top right kind of area. The devices tab.

On the left hand side, we have an applications tab. This is all the applications that are available within this particular installation of seaView. And generally, you have an application for every one of our sensors. So an application for the altimeter, an application for the depth sensor and so on.

The purpose of this video is not to go through each application individually. You’ll find on the USB drive that comes with any of our sensors on our website or even on YouTube.

We have an application-specific video for every one of those apps.

Before you use any of our sensors, I recommend you watch the application video.

It gives you plenty of information and it talks you through every part of the application including all the sensor setup. So, it’s definitely worthwhile viewing that.

The purpose of this video is mainly to cover the operational side of Unity and seaMux.

So getting on to that, down at the the kind of right hand lower part of the page you’ll find a communications window and this is divided into tabs.

We’ve got a tab for Unity, a tab for seaMux, a tab for System Ports, Serial Over LAN, Networks and Monitor.

Unity Topside Control System

On the left hand side we have Port Names. Now you’ll find each of the ports. Port 1, 2, 3, 4 which corresponds with the four physical ports on the back of the Unity control system. Each has its own line of configuration.

So if we start with Unity Port 1, the next column is Power. You’ll find there’s a power button and clicking the power button on any of the ports will enable a power output from Unity on that port, which is ideal if you’re running a a sensor locally on the bench and you want a way to power it.

The good thing about this is it gives you 24V DC power output and it also tells you the current consumption of whatever is connected to that port.

Now, in this example here, we’ve got a Unity control system with four ports in the back of it, and we don’t actually have any sensors connected to them. So, we’re not seeing any power consumption.

So we’ll start with Unity to kick things off. So, under the Unity tab you’ll find it’s divided into a number of columns.

The next column you have is Bridge. And this is for bridging network ports to other ports. We’ll come back to that a little later on.

Next column is your Serial column. This deals with all serial communications on that particular port. So, to enable communications on port, click the open port button. It’ll open the port and it’ll also tell you how that port is configured, whether it’s configured for RS485 or RS232 and what baud rate it’s been configured to.

If you want to change its configuration, on the right hand side of that particular column, you’ll find a settings button. And under there, you can change the mode of the port. So you can set it to RS232, RS485 or RS485 terminated. The latter is where it puts in a termination resistor and you can also set the baud rate of the port and the priority stop bits and word length. And clicking apply will update that port’s settings. You see it updated there in the green text.

Up at the top there’s a universal search parameter for serial devices. Clicking that will search every port for whatever devices are connected to them. Under each of the ports, you can also do an individual configuration of the ports. You can tell it exactly what it is you want to look for. And you can do an individual discover on each of the ports if you don’t want to do a global discovery. So clicking on that, we can tell it which baud rates you want to search for, whether it’s one particular baud rate or all of them.

You can set the timeout, and the timeout is purely how long it waits for response. So when it searches that port for an Impact Subsea sensor, it’ll wait a certain amount of time to get a response from that sensor. 250 milliseconds is usually okay. But if you’re running a particularly complex system, maybe you’re running from the sensor to the topside, you’re running it through several converters, different physical media, and there might be a few things that introduce latency into your communications. In which case, upping that time out to 500 milliseconds or even up to 10 seconds if if you need a really long timeout will let you search for and find the sensors.

You can then set up what the port search is actually looking for. Whether it’s looking for Impact Subsea sensors or whether it’s looking for NMEA devices.

Examples of NMEA devices it might be looking for is the likes of a GPS input. For now we’ll just assume we’re looking for sensors.

So if you’re looking for an Impact Subsea sensor, you can tell it the particular type of sensor you’re looking for or you can leave it set to any. You can also tell the serial number of the sensor that you’re looking for or you can just leave that blank.

Generally speaking, you don’t need to set device type or serial number or configure a specific baud rate. You can leave it all quite open and it’ll do an automatic discovery and it’ll find whatever is on that port.

The only time you might want to put serial numbers in is if you’re doing RS485 multi-drop and you’ve got multiple sensors all connected over the same RS485 bus, they’re all connected to the same physical screened twisted pair. In that case, you need to tell seaView each device that’s connected to it.

And so if you have three altimeters for example and one RS485 bus you put in the serial number of the first altimeter, click Discover, then put in the serial number of the second altimeter, click Discover and then the third altimeter, click Discover and that allows the three altimeters to be discovered one at a time.

Once seaView knows that they are on that RS485 bus, it’ll automatically hold them there and it will handle the communications over that RS485 bus for you. And then at the very end there’s a network side of it as well. So the network side handles anything connected via Ethernet essentially.

So you’ve got a a serial configuration looking for serial items on the port and network configuration looking for network items. So that is all your setup for the the Unity ports.

seaMux ROV Multiplexer

Then if we jump on to the seaMux tab, you’ll find it looks very similar. If we go back to Unity one again, you’ll find the tabs are almost identical. That’s because Unity and seaMux have very similar hardware inside. Both of them have four communication ports. And those four communication ports can all be powered.

They can all be RS232 comms, can all be RS485 comms, and they can all be Ethernet comms. So, in terms of functionality, it’s a very similar setup for the subsea side as it is to the the topside.

So in this particular example we have seaMux running just now and we have a number of sensors connected to it. So again, we’ve got the the port names. This time they’re called seaMux Port 1, 2, 3, 4 and that corresponds with the four 8-pin subcon connectors on seaMux which also have 1, 2, 3, 4 written next to them. So you can physically identify the ports quite easily.

To turn on power to those ports we click the power button. That’ll enable 24V DC output to the sensors. And we can also see that we’ve got current draw on those four ports of varying amounts. That gives a good indication that we’ve got something connected to that port and it’s drawing current.

Bridge Function

Next, we have the bridge function. I’ll touch on this briefly just now. So bridging is really useful. Possibly not so much with Impact Subsea sensors connected, but it is really useful if you’ve got a third-party serial device connected. So a sensor that’s maybe not an Impact Subsea sensor, but it’s outputting serial data and you want to get that into seaMux up through the telemetry into Unity, then you want to get it out of Unity and into a third-party system. In that case, bridging is really useful.

So to bridge a port, say we had a third-party sensor connected to seaMux Port 2. We go along to Bridge, click, select Bridge. There we can then bridge it straight across to any of the Unity ports. So in the back of Unity, we’ve got the four ports in the topside. So we could say, for example, everything coming into seaMux Port 2, I want to bridge across to Unity Port 1. And that’s it now bridged.

So any serial data coming into seaMux Port 2 will be bridged to Unity Port 1 and be available directly out of that port for onward passing the third-party system. Nice and simple.

Now, if you happen to be utilizing seaMux with quite a lot of third-party items, that’s how you set up bridging. Just go to the port, so Port 4, for example, you could say go bridge that Unity Port 3. And then you’ve set up that bridging there.

If you want to remove it, just click the red X and the bridge is broken and the port can now be reassigned.

Of note, the bridging function is only available when you’ve got seaMux and Unity. If you’re running seaMux on its own without Unity topside, the bridging function is not there. So, if you’re trying to get bridging to work on a standalone PC, you’ll find it’s not possible.

Serial Setup

The next column is the the Serial Setup and again, it is exactly the same as Unity. You can enable the serial ports. You can see how the serial ports are set up.

This is also up for RS232. If we had RS485 multi-drop, just simply click on the port you want to change to RS485. Change it to RS485. Click Apply. That’s it up and running. I’ll put this back to RS232 just now because I know all the devices we have connected are RS232 today.

And then you’ve got the network. And it’s actually showing up that we have a network connection on seaMux Port 1 and 3 already. It’s identified that. So it’s likely we’ve got two devices that are communicating over our network there. You can do a network search by clicking this button here, or you can do a serial search by clicking this button here.

We do a network search first. Click there. We can see the devices on the network. So, we’ve got two sonar devices. We’ve got a profiling sonar, an ISP360, and we’ve got an imaging sonar, an ISS360HD.

And if we want to search for the serial, then we’ll go in and click Search Serial. And that shows us all the serial devices connected. So now we’ve got an altimeter connected over serial on seaMux Port 4 and a depth sensor connected to seaMux Port 2.

If you do want to do a global search, there’s this button here. It searches all ports. So it searches serial and it searches network at the same time.

If you are using that, just be aware some devices which have Ethernet and serial, such as the sonars, if it picks up on serial first, it’ll connect to them over serial rather than Ethernet. So sometimes it’s better to search for the network first, get your network sensors and then search for serial. When it comes to the sonars, the profilers and sonars, ideally you want to be connected over Ethernet as that will give you the fastest data transfer from those devices.

And at this point, we’ve got basically everything connected. So we’ve got Unity, it’s connected to the seaMux subsea. We’ve got a profiler and imaging sonar connected and a depth sensor.

And to use any of these devices, we simply double-click on a device and it will launch that device’s application. I can jump back to the Devices page, go through all the devices one at a time, get their applications up and running. And now I’ve got all those applications up and running, and they’re up and running in in tabs.

If I want to put them all together, you can click the the tile view and that just drops all the sensors onto one page and you can move those sensors around and you can drag and drop things and resize things to your heart’s content, really, until you get all the the sensors displayed just as you like them for your particular application.

Again, this software overview video is not really to go through all of the individual applications. So, it’s really just covering the use of Unity and seaMux and how to get things up and running and how to use these two devices.

So, going back down to the the Comms tab, the lower right-hand side, we’ve gone through the Unity setup. We’ve gone through the seaMux setup.

The next tab you’ve got is System Ports. So, this will show you any items connected to Unity or if you’re running the software on PC, it’ll show anything connected to a PC. So if you’ve got anything like a USB to serial converter, it’ll show up in here.

Serial Over LAN

Next, you’ve got Serial Over LAN. So Serial Over LAN is quite a powerful feature. So we can set up serial data to go over a network. It’s very quick and easy to do. You click this button here to add a new port. You set up the IP address for the data, the port number, protocol, and encoding. Click Add, and then that port is now set up.

It’s established. And we can use that port to output data to or bridge it to any of the the Unity or seaMux ports that’s now available on the system.

Network

Something else you can do is the Network tab. If you click on Network tab, it’ll show you the networks that are physically connected to your computer or, in this case, Unity. And in terms of Unity, we have two networks connected. The lower one, the Unity Sensor Network. That network is all about the sensors that are connected to the seaMux and then up from the seaMux into the sensor network port on the back of Unity.

The second network is the Local Area Network, which has a second physical port on Unity and allows connection to any local network you have. So a ship network or a survey network, anywhere you want to get data over, that’s the port to use.

Monitor

The last tab we have is Monitor. Now Monitor is a really useful feature, particularly if you’re routing data around the system and you want to monitor that data and see where it’s at.

This is particularly useful if you’ve got third-party devices. So maybe you’ve got a third-party serial device. It’s outprinting some ASCII data. You’ve got it into one of the ports in seaMux and you’ve routed it to a port on Unity.

You can use the Monitor tab to monitor the data coming into the seaMux port and then you can check it again on the Unity port. So you can see the raw data coming in, you can see the data going out. You can track the data through the whole part of the system.

Now to give you an example of that, what we’ll do is we’ll use the ISA500 that’s connected to seaView currently. So the ISA500, when it connects to seaView, it talks to seaView with a a binary protocol, as do all of our sensors. And if you disconnect it from seaView, it stops talking to seaView. It’ll go back just to outputting standard ASCII data. So we’ll do that.

So the ISA500, you’ve got its device tile here. Device tile, by the way, is really useful. It shows you the serial number. It shows you the firmware version of that sensor and also tells you how it’s connected. So we can see this ISA500 altimeter is connected to seaMux Port 4 via RS232 serial communications and it’s at 115200 baud rate.

And if we want to disconnect it from seaView, the seaView effectively forgets about it. We just click the Delete button. That gets rid of the ISA500. It’s now not talking to seaView. After a few seconds of that, the ISA500 will stop trying to talk to seaView and it’ll go back to outputting ASCII data.

So it’s still connected to seaMux Port 4. So if we go into seaMux Port 4, you can see it’s still powered, it’s drawing currents, the altimeter is there, it’s just not talking to seaView.

So now, if we go into Monitor and you can select any port on the system. So you can select any of the seaMux ports. You can select any of the Unity ports. Even the Serial Over LAN port we’ve created. We can select that to see what we’re putting out that port there. But if we go to seaMux Port 4. Yeah, let’s do that. Let’s go monitor it. So there we go.

We can see the ASCII data coming out from that ISA500. You can see the burst of data coming through from it. Pause that. Now, what we could do here is, we’ve got that data coming into seaMux Port 4. So, what we could actually do is go to seaMux Port 4. Let’s go route that somewhere. Let’s go put that onto Unity Port 1. That’s now bridged. So all that ASCII data coming from the altimeter connected to seaMux Port 4 is now bridged to Unity Port 1.

So if we go back into Monitor and this time, well, we can play it again. We can see the data coming in on seaMux Port 4. Yeah, it’s coming in there. We’ve bridged it to Port 1 on Unity.

So go to Unity Port 1, hit play there, and we can see the data going out on Unity Port 1 as I transmit. So again, let’s pause that. Let’s go back to seaMux Port 4, play. You see it’s all RX data. So seaMux Port 4 is receiving that data. It’s coming into that port. And if we go back to Unity Port 1, you see it’s all TX data.

So it’s all data being transmitted out of Unity Port 1. So we can see that the the bridge we’ve set up from seaMux Port 4 to Unity Port 1 is fully functional. Data is coming in, it’s going out as we’d expect. So it’s really useful for just checking on data, making sure it’s going where you want it to go and it’s all good.

So yeah, that’s a complete overview of the seaMux and Unity and how you use them in seaView V3.2 or above. For any of our other sensors, check out our Products Page, Unity Topside Control System or seaMux ROV Multiplexer pages.

ISS360 Sonar – Key Technical Insights for a simple guide to ROV navigation:

• Range & Accuracy: Provides up to 90m/295ft range with a 2.5mm range resolution using the Impact Subsea Signaling Scheme (IS3)
• Reliability: Utilising an inductively coupled transducer, eliminating slip rings, a common failure point in alternative scanning sonars.
• Versatility: Depth rated to 6,000m in a Titanium housing, features optionally integrated Pitch and Roll for ensuring sonar is level when requiring maximum range performance.
• Operational Modes: Supports 360° continuous scans and high-speed Sector Scanning with flyback for real-time ROV obstacle avoidance.
• Educational Resource: The Impact Subsea Academy provides free technical training and seaView software tutorials.

In the world of subsea operations, visibility is rarely a given.

Whether you’re navigating a narrow pipeline corridor or piloting an ROV through silt-heavy waters, the difference between success and a “near miss” often comes down to the quality of your sonar imagery.

At Impact Subsea, we’ve been putting the Impact Subsea ISS360 Imaging Sonar through its paces.

Today, we’re sharing a series of operational films that demonstrate why this compact sonar has become the standard for underwater navigation and target identification.

The Tech Behind the Image

The ISS360 isn’t just small, it’s the world’s smallest scanning, imaging sonar. Utilising the Impact Subsea Signalling Scheme (IS3) it provides a range of up to 90 meters with a class-leading range resolution of 2.5mm.

What truly sets it apart in the field, is the inductively coupled transducer. By removing the need for slip rings, the ISS360 offers unparalleled longevity and reliability, ensuring that it won’t fail when you need it most.

See it in Action:

We’ve curated six key scenarios that every ROV pilot and offshore engineer will recognise:

1. The 360° Perspective.

Watching the ISS360 identify pool walls and obstacles with 2.2° angular resolution.

2. Sector Scanning.

How “flyback” mode provides the rapid update rates required for high-speed navigation.

3. Low Visibility Control.

When the camera feed goes dark, the ISS360 provides the awareness necessary to stay on mission.

4. Long-Range Detection.

Identifying everything from seabed debris to surface waves from nearly 100 meters away.

5. Intuitive Navigation.

Aligning sonar data with pilot perspective.

6. Real-Time Structural Mapping.

Identifying boundaries in confined spaces.

The Impact Subsea Academy

Impressive hardware is only as good as the operator behind it. That’s why we highly recommend the Impact Subsea Academy. It’s a comprehensive resource designed to help users get the most out of their sensors.

From explainer films on the seaView software to technical FAQ’s the Academy ensures that your team isn’t just seeing data but interpreting it correctly to make safer, faster decisions.

The Future of Subsea Autonomy

With the release of an open-source SDK, the ISS360 is now paving the way for the next generation of AUV autonomy. It’s no longer just about avoiding obstacles, it’s about providing the high-fidelity data required for AUVs to “understand” their environment.

Are you ready to upgrade your subsea vision?

Explore the full technical specifications on the ISS360 Page.

Technical Authority & Data Integrity

This guide is authored by the engineering team at Impact Subsea and is based on over a decade of pioneering underwater sensor development. All specifications, including the 6,000m depth rating are derived from rigorous pressure-chamber testing, ISO-certified manufacturing standards and real-world offshore field deployments. As the original equipment manufacturer (OEM), Impact Subsea provides this data as the definitive technical baseline for the ISS360 Imaging Sonar.

Together, these two high-performance solutions, subsea multiplexer & topside control system are designed to streamline sensor integration, simplify telemetry and enhance data management for demanding subsea vehicle operations.

seaMux – Subsea Multiplexer

seaMux is a highly compact, titanium-housed subsea multiplexer engineered to support a wide range of underwater instrumentation, including sonars, profilers, altimeters, depth and Attitude and Heading Reference Systems (AHRS).

Rated for depths up to 6,000 meters, it is equally suited for shallow and deep-water applications.

The system features four versatile communication ports, each supporting Ethernet, RS232 or RS485 protocols.

To ensure scalability, users can daisy-chain multiple seaMux units together or leverage RS485 multidrop and y-splice cables to host multiple serial sensors on a single port.

Each port is paired with a software-controllable 24VDC power output featuring real-time power monitoring.

Data transmission to the surface is incredibly flexible, utilising either standard Ethernet or high-bandwidth VDSL telemetry over a single screened twisted pair.

Unity – Topside Control System

To complement the subsea hardware, Unity Control System serves as the topside control interface for the underwater sensor suite.

Housed in a 1U high, 19-inch rack-mountable form, Unity runs Impact Subsea’s powerful seaView software.

seaView allows operators to easily view, log and manage sensor data while facilitating data flow in and out of seaMux and Unity.

Mirroring the versatility of the subsea seaMux, the Unity system features four communication ports (each capable of providing RS232, RS485 or Ethernet) with software-controllable 24VDC power to manage local, topside connections.

A remarkable capability of the combined system is port bridging, which forms a seamless link between a port on seaMux and a port on Unity topside interface, allowing for the transparent throughput of any third-party data.

This allows Unity and seaMux to be used with a combination of Impact Subsea sensors and third party sensors. Or purely with third party sensors and instrumentation.

“seaMux is a compact and highly flexible subsea multiplexer,” stated Ben Grant, Managing Director of Impact Subsea. “A complete sensor suite can be connected to seaMux and controlled from seaView running on Unity.

In addition to supporting Impact Subsea sensors, the system also allows connection of third party sensors and instrumentation.

Those looking for a compact and flexible subsea multiplexer and topside control system for use on underwater vehicles now have a new highly capable solution available to them”.

Impact Subsea Launches Advanced Subsea Multiplexer and Topside Control System – Film Transcript

Hi, I’m Ben Grant, Managing Director of Impact Subsea.

Today, we’re excited to announce the launch of two new products.

Firstly, we’re launching seaMux, a highly compact subsea multiplexer. Depth rated to 6,000m and available in a fully titanium housing.

seaMux provides the capability to network together multiple Impact Subsea sensors or third party sensors.

seaMux itself provides you with four communication ports. Each port can be individually set up to either be Ethernet, RS232 or RS485 serial communications. This allows Ethernet sensors to be connected along with serial sensors.

Once all the sensors are connected, there’s a connector for transmission to the surface and this can be over Ethernet communications or VDSL.

VDSL is quite a unique feature in that it allows us to put together a whole suite of sensors and transmit all the data over a simple screened twisted pair.

This allows a high bandwidth capability to be added to ROVs that don’t have Ethernet, don’t have fiber. An example setup is to have seaMux with two Impact Subsea profilers, an imaging sonar, a depth sensor, an altimeter, and a heading sensor all running into the one unit here and transmitted back to the surface.

seaMux itself is primarily intended for use with Impact Subsea sensors, but it can also be used with third party sensors. Any sensor which has Ethernet telemetry or RS232 or RS485 serial telemetry can have its data put through seaMux, transmitted to the surface and broken out topside for interfacing to a third party system.

In addition to seaMux, we’re also launching Unity which is our topside control system. Unity is a full computer and communications interface in a 1U high 19-inch rack-mountable form factor.

The front is a very clean design. You have a power button, a couple of USB ports to allow getting data in and out the system, and a couple of inlets for air cooling of Unity.

On the back of Unity, you have a number of ports here. These four ports can all be serial or Ethernet ports, and they can be for direct connection to a sensor, or they can be for outputting data that’s input into the seaMux.

Then you’ve got your connection from the topside to subsea, which can either be Ethernet or VDSL.

Then you have a number of ports, standard computer ports and a power input for Unity.

So Unity and seaMux work hand in hand and provide the capability to have a full sensor suite of Impact Subsea sensors plus additional third party sensors.

Unity and seaMux can also be used purely with third party sensors if required.

Full product specifications can be found on the Unity and seaMux webpages.