The New Gemini 1200id

An easy upgrade path to higher resolution imaging for work class ROVs

The Gemini 1200id is built on the same robust platform as the industry standard Gemini 720is sonar. It features a wide 120° horizontal field of view when operating at both 720 kHz and 1200 kHz acoustic frequencies and offers improved attenuation of waterborne electrical noise for optimal imaging performance.

An integrated speed-of-sound sensor ensures that targets are displayed to a high degree of positional accuracy. CHIRP processing provides improved target separation over longer ranges.

The 1200id is fully compatible with Tritech’s software package, Genesis. This ensures improved user interaction and allows for control of multiple Tritech products from within one software package. Software development kits (SDKs) are also available for Windows and Linux operating systems.

Bruce Hardy, Sales and Marketing Director, commented:

“We are really pleased to bring the new dual frequency Gemini 1200id to market. Having listened to our customers’ requests for higher definition and enhanced target resolution we believe the new 1200 kHz acoustic frequency will provide just that, along with Tritech’s reputation for quality and reliability, backed by our 3-year guarantee.”

Unrivalled Imaging Performance

The Gemini 1200id employs a completely in-house developed analogue front-end solution that incorporates fully differential receiver channels for enhanced acoustic reception. Internal electronic circuits have been optimised and where necessary additional filtering exclusively employed to minimise self-generated noise. The sonar also actively attenuates external waterborne noise from other subsea equipment in the vicinity of the sonar. These enhancements enable the Gemini 1200id to produce sonar images displaying sharp and bright acoustic returns on a noise reduced background resulting in crisp sonar images of impressive clarity.

Asim Azad, Hardware Engineering Manager, commented:

“With its ultra-low-noise differential analogue front-end supporting a wide dynamic range optimised for sonar imaging applications, and with its ability to actively attenuate waterborne electrical noise from other subsea equipment, the Gemini 1200id provides work class ROV operators the clarity and confidence necessary for mission critical operations.”

Further Reading - 

The Gemini 1200id is the latest addition to Tritech’s multibeam sonar portfolio and is targeted specifically at work class ROVs and other applications where reliability is of the utmost importance. Based on the industry standard Gemini 720is platform, the Gemini 1200id employs a mechanical design that is tried and tested in the harshest of subsea environments and offers a degree of redundancy by design not afforded by any other platform. The sonar has been developed largely in response to requests from existing customers who regularly operate the Gemini 720is to depths as low as 4,000 metres below sea level.

In addition to the 720 kHz acoustic frequency offered by the Gemini 720is, the Gemini 1200id introduces dual frequency operation with the addition of a new 1.2 MHz acoustic operating frequency which improves angular resolution from 1⁰ to 0.6⁰ and range resolution from 4 mm to 2.4 mm, resulting in a significant improvement in resolution.

The introduction of the 1.2 MHz acoustic operating frequency to the Gemini 1200id necessitated a redesign of the analogue front-end electronics to handle the higher sampling rate requirements of the new higher-frequency mode of operation. Rather than taking the easier and cheaper route of transitioning over to single-ended analogue front-end integrated circuits developed for ultrasound applications as typically used by the majority of other multibeam sonars, the Gemini 1200id continues to employee an in-house developed analogue front-end solution that incorporates fully differential receiver channels consisting of discrete low-noise amplifiers, discrete variable gain amplifiers, second-order bandpass filters, and discrete high-speed, high-resolution serial ADCs. This custom analogue front-end solution allows the receiver to be optimised for longer-range sonar applications rather than shorter-range medical ultrasound applications which primarily drive the development of ultrasound analogue front-end integrated circuits due to the relatively larger volumes involved. As a result of its superior analogue front-end tailored for sonar applications, the Gemini 1200id has a dynamic range twice as wide as its nearest competitor.

The electronic circuits within the Gemini 1200id have also been optimised and where necessary additional filtering exclusively employed to minimise self-generated noise around the two acoustic operating frequencies resulting in significant reductions in unwanted artefacts that can appear in the sonar image. In addition to this, the Gemini 1200id actively attenuates external waterborne noise from other subsea equipment in the vicinity of the sonar, including from the likes of ROV thrusters which have a tendency to generate relatively large levels of electromagnetic interference. By pushing self-generated electrical noise away from the acoustic operating frequencies, and by actively attenuating external waterborne electromagnetic interference, the Gemini 1200id offers welcomed improvements in SNR.

The wide dynamic range and enhanced SNR of the Gemini 1200id enable it to produce sonar images displaying sharp and bright acoustic returns on a noise reduced dark background resulting in crisp sonar images of excellent clarity.

A flight-time sensor operating at 1 MHz and integrated into the side of the Gemini 1200id measures the speed of sound in the water immediately around the sonar at the time of acoustic reception to ensure that observed targets are displayed accurately for position and size.

All auxiliary port features supported on the Gemini 720is are also supported by the Gemini 1200id, and the depth rating of 4,000 metres is maintained, ensuring that the Gemini 1200id offers a direct upgrade path for customers who until now have been reluctant to consider anything beyond their trusted Gemini 720is sonars for mission-critical operations.

The Gemini 1200id can be controlled using either Genesis or software development kits that support integration into third party applications. Genesis is Tritech’s latest all-in-one software package for controlling, displaying and recording data from its portfolio of sensors. It boasts a modern, dynamic and easy to use interface with a comprehensive suite of integrated features.

To allow the Gemini 1200id to share bandwidth with other equipment and sensors that may be present on an existing or shared network connection, the data bandwidth consumed by the sonar can be limited by capping the ping rate, reducing resolution, or enabling data compression.

Every Gemini 1200id sonar that rolls off the production line is subjected to a strict factory acceptance testing regime to guarantee quality and performance. As part of this testing, every function of the sonar is verified and additional tests at pressure limits conducted to confirm operation under extreme conditions. The design of the sonar is qualified to ensure reliability against shock and vibration, corrosion, and for compliance against relevant EMC regulations.

All purchases of the Gemini 1200id are available with an extended warranty of three years. Although the Gemini 1200id is based on a proven and reliable platform, extended warranty provides customers with peace of mind so that they can concentrate on conducting their mission-critical operations under the certainty that the Tritech support network is available to offer advice and support 24 / 7, 365 days a year.

BIO

Asim Azad, Hardware Engineering Manager, Tritech International: Asim joined Tritech in 2012 and holds a master’s degree in Electronics and Electrical Engineering from the University of Edinburgh, Scotland. After previously working in the semiconductor industry, over the last twelve years he has been involved in the development of mechanically scanned and multibeam sonar systems. As Hardware Engineering Manager, he is responsible for the hardware development team at Tritech International.

More information on the new Gemini 1200id can be found here.