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Exails LBL system provides an accurate and coast effective subsea positioning solution and monitoring capabilities down to 4,000m of water depth. Bringing together Canopus intelligent transponders, Ramses transceivers, Inertial Navigation Systems and Delph Subsea Positioning Software, it offers advanced sparse LBL capabilities that allow operators to reduce the number of transponders deployed on the seabed with no compromise on performance, resulting in substantial cost savings in the field.
Powering advanced LBL capabilities
High performance
Exail’s 4,000m depth rated LBL positioning solution comprises the Canopus transponders and Ramses transceivers. This absolute subsea positioning system enables highly accurate and reliable deep-sea operations by providing operators with centimetric positioning accuracy in water depths down to 4,000m.
 Ramses |  Canopus | |
|---|---|---|
Depth rating | 4,000 | 4,000 |
Precision (mm) | < 10 | < 10 |
Autonomy (pings at max sound level) | n/a | 1,600 000 |
Transducer beam shape | Omnidirectional | Omnidirectional |
Acoustic communication | 500 bps / 8kbps | 500 bps / 8kbps |
Data logging (Gb) | 32 | 32 |
| Learn more | Learn more |
Sparse-LBL: enhancing accuracy and cost savings with fewer Transponders
When coupled with inertial navigation systems (INS), the ranges measured by the Ramses are used in the navigation solution of the Kalman filter of the INS to improve accuracy and precision of the positioning solution, thanks to the tight coupling of acoustic and inertial technologies. This is Exail’s concept of “Sparse-LBL”, that powers cost-efficient subsea operations by reducing the number of transponders deployed on the seabed, thus decreasing the time spent on transponder deployment.
The vehicle’s INS has a position standard deviation built up from DVL-aided INS navigation.
The Ramses transceiver is within acoustic range of a Canopus transponder. The range measurement narrows down the possible vehicle’s positions.
The standard position deviation is further improved as more ranges are received.
Tight INS/LBL integration and data fusion further enhances the subsea vehicle’s position accuracy and precision using only one single transponder.
The following table gives the performance that can be reached depending on the number of transponders used:
Mode | Positioning accuracy | |
|---|---|---|
4 Transponders | LBL / range aiding | <0.1 m |
3 Transponders | LBL / range aiding | <0.2 m |
2 Transponders | Range aiding | <0.5 m |
1 Transponder | Range aiding | <1 m |
Robust acoustic communication
In addition to the precise positioning of subsea assets, most subsea applications require robust acoustic communication links to be established between the surface, the subsea vehicles, and the deployed transponders. Exail transceivers offer two different communication modes:
- Telemetry
- Modem
A robust and low bit rate acoustic communication link at 500 b/s that can be used to retrieve sensor measurements and perform baseline collection.
A high bit rate acoustic communication link at 8 kb/s that allows end users to recover measurements that have been logged by the Canopus transponder over long periods of time.
Thanks to its hundreds of acoustic codes for interrogation and reply, Exail Canopus transponders can be used in the most complex environments without any acoustic interferences, ensuring highly reliable subsea operations.
Embedded environmental sensors
Canopus and Ramses, besides enabling underwater acoustic communication, integrate temperature, pressure, and inclinometer sensors. Canopus transponders can be upgraded with optional sensors like Digiquartz pressure sensor and Valeport sound velocity sensors for enhanced efficiency. Both Canopus transponders and Ramses transceivers support real-time data transmission to the surface via a robust acoustic link. Additionally, they feature a data logging function for occasional data retrieval, recording information from internal or external sensors on the transponder's internal memory.
Multiple operating modes
Operating the Canopus and Ramses LBL solution on subsea operations gives operators greater flexibility thanks to multiple operating mode capabilities.
Calibration
- Box-in
- Baseline acquisition for array adjustment
- SLAM (Simultaneous Localization and Mapping) – Simultaneous vehicle positioning and fixed-transponders calibration
Positionning
- LBL: Positioning of the transceiver or a mobile transponder within an array of at least 3 transponders.
- Range aiding (interfaced with an INS) : a robust positioning solution compared to LBL, leveraging the quality of a fused position from the INS.
Unrivaled operating life
Low power consumption
With their extremely low power consumption, the Canopus LBL transponder and Ramses LBL transceiver offer unrivaled battery life. A standard Alkaline battery pack will provide up to 70 months or 1,600,000 pings of battery life in listening mode, while a Lithium battery will ensure up to 140 months of battery life or 2,800,000 pings for long duration subsea operations.
Individual interrogation schema
Legacy LBL systems perform common interrogation as this was historically required to calculate a purely acoustic position. With the wide availability of Exail’s industry leading inertial navigation system, the use of range aiding allows the use of an individual interrogation scheme which greatly reduces the battery consumption of individual beacons.
Corrosion-free beacons
The Canopus transponders and Ramses transceivers are highly reliable equipment able to endure the harsh conditions of subsea environments. Fitted with a cathodic protection (anodes located on the upper and lower parts of the transponders) they are resistant to corrosion and can be deployed at sea for long duration operations.
A user friendly LBL solution
A positioning solution open to third-party equipment
The Ramses transceiver and Canopus beacons support acoustic positioning codes of major third-party suppliers, easing their integration in an existing pool of equipment
Dedicated training courses
Striving to bring the best user experience possible and help operators make the most of their subsea positioning solutions, Exail offers various trainings, both online and within its own training center in Aberdeen.
E-learning trainings available online cover topics such as:
- Introduction to subsea INS and acoustic positioning principles
- Hands-on training using DSP on existing data sets
- Equipment description
An efficient supervision software suite
To manage the increasing complexity of subsea operations and to offer a solution that is easy to deploy and use, Exail developed a global supervision software that integrates the full range of Exail subsea systems: Delph Subsea Positioning Software.
An intuitive and dynamic software used to plan, operate and post-process Exail subsea positioning products, Delph Subsea Positioning (Delph SP) simplifies the planning, simulation, operation and post-processing of subsea positioning tasks.
Comprising three intuitive and user-friendly core modules, Delph SP is an easy-to-use yet powerful tool enabling even the most complex subsea operations by making each step of the subsea positioning operation simpler, error-free and faster, saving vessel and man time.
A LBL solution covering all applications
The Canopus and Ramses LBL solutions, along with Exail subsea INS, are being operated worldwide for diverse applications in the energy, geoscience, marine civil engineering and defense markets.
Applications include:
- ROV positioning
- AUV navigation
- Metrology
- Underwater geodesy and seismics
- Environemental monitoring
- Structure monitoring
- Structure placement
- Subsea construction
- Drilling
- Mining (crawler positioning)
- Mine Countermeasures
