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 signaling the ISS360 & ISS360HD imaging sonars also benefit from the Impact Subsea Signaling 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

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

The ISD4000 Depth & Temperature Sensor is a widely used high accuracy depth and temperature sensor on Remotely Operated and Autonomous Underwater Vehicles.

It can also be used to monitor the depth of any item being deployed underwater with a high level of accuracy and precision.  The optional integrated Attitude and Heading Reference System provides a useful additional sensing capability.

Depth Measurement:

The ISD4000 is equipped with a temperature compensated piezoresistive pressure sensor that is able to sense absolute pressure to 0.01% of Full Scale (FS) accuracy (0.005% full scale option is also optionally available).

To enable the highest level of accuracy for the depth of operation in a particular application; the ISD4000 is available in a number of pressure ranges. 10, 30, 50, 100, 300, 400 and 600 Bar pressure configurations are offered.  As a rule, when working in depths up to 100 meters, a 10 bar sensor should be used. Depths up to 300 meters would necessitate a 30 Bar sensor and so forth.

When calibrated to 0.01%FS accuracy, this enables a pressure accuracy of ±0.001 Bar for the ISD4000 which has a full scale of 10 Bar.  Or ±0.06 Bar for the ISD4000 with a full scale of 600 Bar.

This is the overall accuracy level; the relative accuracy of the sensor may be greater than this value.

The measured pressure is then converted to a depth measurement using an industry standard UNESCO pressure to depth algorithm which also takes into account the local gravity in the area of operation.

The pressure sensor itself is protected by a black acetal end cap.  This end cap provides physical protection of the pressure sensor while also locking in the pressure sensor and temperature probe.  The protective cap can be removed quickly to allow cleaning of the pressure sensor to remove build up of salt or sand. 

This also allows the ISD4000 Depth & Temperature Sensor to be connected to a calibration block for pressure calibration or pressure verification without the need to strip the sensor down. Having the pressure sensor close to the exterior of the sensor ensures that no blockages can occur which would result in a stuck pressure/depth reading.

When compared to alternative resonant quartz-based pressure sensors, the temperature compensated piezoresistive pressure sensor has the advantage of longer-term stability. This allows a longer duration between pressure calibrations.

In addition, the pressure sensor itself is physically smaller and more compact, providing enhanced shock and vibration performance. 

Temperature Measurement:

The ISD4000 is equipped with a Resistance Temperature Detector (RTD) which provides temperature measurements to ±0.1°C (±0.05°C accuracy is also optionally available).

The temperature probe itself is made of stainless steel to provide excellent thermal transfer properties.  The stainless-steel probe is hollow and the RTD is embedded within this.  This enables a very low latency temperature readings to be provided.

Attitude & Heading Reference System:

The ISD4000 is optionally available with an in-built Attitude and Heading Reference System (AHRS).  This provides Heading, Pitch and Roll as a secondary output.

This also provides a Turns Counter output from the ISD4000.  This allows the rotations about a specific axis to be reported on (Heading, Pitch or Roll).  This can be highly useful for tether or cable management.

Within the ISD4000 there are three gyroscopes, three accelerometers and three magnetometers.  The outputs from these are fused together to provide the AHRS functionality.  The raw data from each of these sensors can also be made available as an output should this be required.

Depth & Temperature Sensor Interfacing:

The ISD4000 Depth & Temperature Sensor 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 depth sensor, making the ISD4000 a very simple sensor to retrofit to existing systems.

Software Configuration:

One of the key benefits of the ISD4000 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.

This allows the latitude of operation to be entered, any depth or pressure offsets, tare functionality to remove the effect of atmospheric pressure etc.

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

The below video provides an overview of the ISD4000 Depth & Temperature Sensor application showing where all the core elements of the user interface are and highlights the settings available on the ISD4000 sensor itself.

Physical Configuration:

To ensure the ISD4000 Depth & Temperature Sensor can be used in all underwater depth sensing applications, a variety of physical configurations exist. The ISD4000 is available in Titanium or Acetal materials, both with excellent longevity.

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

The ISD4000 offers a Depth/Temperature/AHRS sensing capability in a very compact form factor:

The acetal housed ISD4000s are available in 10, 30 & 50 bar configurations. This is due to a 500 meter maximum depth rating of the acetal housing.  The Titanium housed ISD4000 sensors are available in all pressure configurations.

Robustness:

The ISD4000 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 with all components being 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.

Calibration:

To calibrate the pressure sensor within the ISD4000, this is accomplished through the use of a primary measurement source. This is a Dead Weight Tester complete with weights. A high accuracy atmospheric pressure sensor is also required.

An ISD4000 calibration block is available which allows the simple connection of the ISD4000 pressure sensor directly to the hydraulic pressure output of a dead weight tester:

Within the supplied seaView software is a calibration process which will talk the user through the process.  By default, a five-point cubic interpolation calibration is performed. Five known pressures are provided across the span of the pressure calibration. Pressure points near the maximum and minimum values are used together with uniformly distributed pressures across the range.

Overall:

The ISD4000 is a highly compact survey grade Depth & Temperature sensor with optional integrated Attitude and Heading Reference System.

The ability to configure all aspects of the sensor in software allows quick configuration and ease of integration into any new or existing system.

The robust design ensures that the ISD4000 is suitable for the most challenging of underwater environments.

The latest ISD4000 Depth & Temperature Sensor datasheet, manual, 3D model and further technical information can be found on the ISD4000 product page.

If you would like to discuss the ISD4000 Depth & Temperature Sensor in more detail and how it can be used in your underwater application, please drop us an email at support@impactsubsea.co.uk

Transcript – ISA200 & ISA500 Accuracy & Performance

Welcome to a deep dive into, well, the truly cutting edge world of advanced underwater sensing.

Today we’re putting the ISA200 and ISA500 Altimeters from Impact Subsea under the microscope. Yeah, these aren’t just any sensors. No, they promise really unparalleled perception beneath the waves. And we’re here to unpack exactly how they do it.

Our mission really is to show you why these devices are such a game changer. We’re talking precision, reliability in the toughest environments, too. Exactly. in the most unforgiving parts of the ocean. We’re looking at tech that tackles the real challenges of working deep underwater, bringing a whole new level of clarity.

Okay, so let’s dive into their capability first. These are sonar based devices, right? Using sound to measure distance. That’s right. And the ISA200, it can range over 250 m. That’s what about 820 ft. Yeah. Impressive range. And the ISA500 goes beyond 120 m. So 393 ft.

But what really gets me is how the environment itself changes that range. It’s not fixed. It’s true. And it makes sense when you think about it. What the sonar is actually pinging off makes a huge difference. Like what? Well, think about a solid reflective target like rock. That can give you a much greater distance reading, sometimes over 175m for the ISA500. Okay. But if you’re aiming at something softer, maybe marine growth or sediment plumes, much fuzzier target. Exactly, that range might drop to 80m maybe even less. The clever part here is how these altimeters actually optimize their sensitivity. Ah they adjust. They adjust. Yeah. To give you the best possible reading whatever conditions you’re facing down there. That’s incredible.

But how do they maintain any kind of precision with all that variability? I mean this is where it gets truly mind-blowing for me. These sensors boast an astounding 1mm accuracy and repeatability. 1 millimeter. That’s tiny. It is barely the thickness of a credit card. like you said. So, how do they achieve that kind of pinpoint precision through water which can be so murky and unpredictable? It’s a fantastic question and it’s down to a really advanced digital correlation technique. Imagine trying to pick out a tiny clear radio signal in a storm of static. This technique is like a super advanced filter, right? It rapidly sifts through literally millions of echoes, actually two million times per second to find the true signal, ignoring the noise. 2 million times a second. Wow. Yeah.

And this isn’t just about resolution, which lots of sensors talk about. What’s the difference there? Well, resolution just tells you the smallest change it can detect. Accuracy tells you how close that measurement is to the actual real world distance. I see. So, it’s not just detecting tiny changes. It’s knowing those changes are correct. Precisely. The ISA200 and ISA500 deliver both. And that’s absolutely critical for jobs that used to need much more complex, often fragile laser systems. Like what kind of jobs? Things like detailed pipeline surveys or maybe precisely docking an ROV with some subsea equipment. Tasks where being off by even a little bit matters a lot. This is a huge leap in underwater reliability.

Okay, so the sensor is incredibly precise, but how do you know the data itself is trustworthy, especially if the water is murky or full of particles? All right, good point. That’s where their correlation factor comes in. Think of it like a built-in quality check, a confidence score for each echo. A confidence score. Yeah. If the sensor isn’t at least say 50% confident that an echo is a genuine reflection, if it’s below a 0.5 correlation, it just ignores it. So, it filters out the dodgy readings automatically. Exactly. You’re only getting data that the system itself considers reliable. Every reading you get is one you can trust. That’s brilliant. Intelligent data right out of the box.

But, how adaptable are they? If you’re in a busy subsea area with other acoustic gear, maybe. Yeah, that’s key. Their adaptability is fantastic. The ISA500, for instance, lets you actually adjust its operating frequency. Oh, okay. Anywhere between 400 and 600 kHz. So, you can actively steer clear of interference from other sensors. Smart.

And what’s more, pretty much all their settings are fully software configurable through seaView. You can tweak detection modes, maybe use strongest detection if you’re navigating through suspended sediment. Or you can even use a multi-echo capability for tracking several targets at once. It’s like having a well Swiss Army knife for underwater sensing.

And it gets even more visual, doesn’t it? There’s an optional ECHOGRAM feature. That’s right. That essentially turns them into single beam imaging sonars. Imaging sonars. Wow. Yeah. It visualizes the whole water column and the seabed below. You get up to 2,000 data samples per ping, giving you a real-time picture. Really helps with visual ID of what’s down there. Okay, that’s impressive.

What about vehicle movement? If the ROV or AUV is tilted, yes. Slant range. A standard altimeter might just give you the distance along that tilted path, which isn’t your actual height off the bottom. Exactly. But with the optional built-in AHRS, that’s an attitude and heading reference system, like in drones. Sort of. Yeah. It constantly knows the vehicle’s pitch and roll. It does the trigonometry internally to correct that slant range and give you the true vertical altitude. So you always know your actual height regardless of tilt precisely. Very clever.

So okay, incredible intelligence, pinpoint precision, but underwater gear takes a beating. How tough are these things? How are they engineered for endurance? Well, they’re built for it. Seriously tough. Construction is from titanium or acetal. Very durable materials. And the depth ratings, the ISA500 is rated up to an incredible 11,000m. 11,000m. That’s deeper than Everest is tall. That’s Mariana Trench territory. Literally capable of reaching the deepest parts of our oceans.

Wow. And it’s not just about pressure. They’re rigorously tested to API 17F standards for shock and vibration, which means it means they’re basically put through hell in testing. Extreme shocks, crazy vibrations, way beyond normal operational use. So you can absolutely trust they won’t fail when it matters most thousands of meters down.

Okay, so we’ve really covered a lot. Incredible range, that pinpoint 1 millimeter accuracy, intelligent data quality, all wrapped up in a design that’s robust and amazingly adaptable. Yeah, what stands out, I think, is just the meticulous engineering. It brings real insight, genuine reliability to the underwater world. It transforms what’s actually possible in these really challenging environments.

So wrapping this up, what does this all mean for you? When every single millimeter counts, how might these kinds of precise, reliable eyes continue to shape how we understand and how we interact with our planet’s last unexplored frontiers? What new possibilities open up down there?