Altimeter & Single Beam Echosounder

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Introducing the ISA500

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The ISA500 underwater AUV & ROV Altimeter & Echosounder provides exceptionally long range measurement capability – in excess of 120 meters.

In addition to providing exceptionally long range capability, the sensor has a 1mm accuracy – allowing precision underwater distance measurements to be made.

Optionally, the ISA500 can also be provided with an integrated Attitude and Heading Reference System (AHRS). This provides highly stable Heading, Pitch and Roll readings.  

Another optional capability is ECHOGRAM, providing sonar backscatter data for each ping.


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Altitude & Echosounding

The ISA500 utilises sonar technology to derive distance measurement.

Operating by default at 500kHz, the sensor utilises a broadband composite transducer and electronics together with an advanced digital acoustic engine. The combination of these enable the sensor to achieve long range and high accuracy.

The sensor can be operated at any frequency from 400 to 600kHz – ideal for different applications or operating in conjunction with other hydro-acoustic or sonar equipment.

The ISA500 provides a single range measurement per ping (for use as an underwater Altimeter). With ECHOGRAM enabled the ISA500 can provide sonar backscatter data (for use as an Echosounder).

Attitude & Heading Reference System (AHRS)

Optionally available on the ISA500 is an integrated Attitude & Heading Reference System (AHRS) providing Heading, Pitch & Roll.

The AHRS is based on Micro-Electrical-Mechanical-System (MEMS) based technology.

Within the ISA500 there are three MEMS based Gyros, Accelerometers & Magnetometers. The outputs from each of these MEMS devices are fused together, providing highly stable Heading, Pitch & Roll.

The Heading is highly resilient against temporary magnetic interferes. This is aided by a soft and hard iron calibration feature once the unit has been installed on the ROV, AUV or other underwater application.


ISA500 - Echogram app in seaView software. Underwater imaging

Optionally available on the ISA500 is ECHOGRAM. This new feature adds a full backscatter capability to the 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.



Provides Altitude readings in excess of 120 meters above the seabed. Also provides Heading, Pitch & Roll. Can emulate any other Altimeter – making integration into any Autonomous Surface Vehicle (ASV) Autonomous Underwater Vehicle (AUV) or Remotely Operated Vehicle (ROV) very easy.

The high level of accuracy also ensures that precise positioning of the vehicle can be obtained. 

Reduce the equipment required to provide Altitude, Heading, Pitch & Roll by using a single ISA500 unit.

Measure distance to a target underwater with 1mm accuracy.

Ideal for final positioning of equipment underwater, positioning a tool in real time, monitoring under ice distance measurements etc

Using the multi-echo capability, measure the distance to and between multiple targets in one ping.

Monitor the height off the seabed together with the Pitch, Roll and Heading of the equipment. Provides a clear understanding of equipment position and attitude.

Ideal for touchdown monitoring applications. 

The ISA500 provides the ideal sensor for detecting flooded members underwater. The high accuracy and sensitivity of the unit allows a precise and accurate check to be conducted. Within seaView a dedicated FMD application is provided. The FMD application provides all that is required to conduct, log and report on underwater flooded members.


Read more about the ISA500 & FMD Application in the system datasheet here.

Using the seaView software, conduct single beam echo sounder survey and monitor the build up and movement of sediment.
The ISA500 can also be permanently mounted to monitor scour erosion around foundations of bridges, wind turbine monopiles etc.

Monitor Altitude above the seabed and also the Pitch, Roll and Heading of the Magnetometer or Towfish.

The ISA500 is ready for direct integration with a variety of Magnetometers (such as the G882).

With a range capability in excess of 120 meters and an accuracy of 1mm, the ISA500 is an ideal single beam echosounder which can be deployed from a boat or ASV.

The seaView software allows logging of all data gathered and has a GPS input capability to georeference all data.

Optionally the ISA500 can be provided with ECHOGRAM capability.  This provides sonar backscatter data, allowing the complete water column to be visualised. 

With RS232, RS485, Analogue Voltage and Analogue Current interfaces, the ISA500 can easily be interfaced with other Oceanographic sensors and systems.

When mounted to a surface buoy the ISA500 can measure the altitude below the buoy – ideal for wave height measurement.

The ISA500 can also be mounted facing upwards to monitor wave height from the seabed. 

An ISA500 For Every Underwater Distance Measurement Application

The ISA500 is available in 1,000, 6,000 & 11,000 meter rated housing configurations. Housings are offered in either Titanium or Acetal.

Both forward looking and right angle housing configurations are available – enabling simple integration into any underwater vehicle, towed asset or structure.

An OEM version of the ISA500 is also available, which offers an un-housed version of the ISA500 for integration into a third party housing or system. Alternative connector options are also available upon request.

ISA500 Options

Use this flowchart to find the ideal configuration of ISA500 for your application

The Impact Subsea Academy is a help center and knowledge base. It has been set up for you to be able to search for articles on anything from your first steps to the most advanced features.


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