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Robust offshore navigation in GNSS-denied environment
The challenge
Offshore operations such as pipe laying, cable laying, rock dumping, and construction work depend on precise platform positioning. Traditional GNSS-based navigation is vulnerable to signal disruption — whether from environmental conditions, intentional jamming, or spoofing. In high-stakes environments, an interruption in positioning is not an option. A loss of accurate positioning data can compromise operational safety, delay critical tasks, and increase costs — particularly in deepwater or congested offshore fields where precision is essential to avoid collision or damage to subsea infrastructure.
The solution
To ensure uninterrupted, high-accuracy positioning regardless of GNSS availability, Exail combines acoustic positioning, inertial navigation, and hybrid data fusion into a single integrated solution, using fixed transponders deployed on the seabed as positioning references.
Exail's Gaps M7, a high-performance USBL system with a built-in Phins Compact C7 INS, provides a comprehensive answer to GNSS-denied navigation. Deployed on a surface platform, it integrates multiple positioning inputs to maintain accuracy at all times:
- LBL ranges from Canopus transponders deployed on the seabed
- Inverted USBL positioning
- Inertial navigation via the embedded Phins Compact 7 INS
- DVL velocity data (optional, for enhanced robustness)
- GNSS when available, for hybrid navigation
Canopus transponders are deployed on the seabed as fixed acoustic references. Once geolocated — via GNSS or acoustic survey — they serve as reliable reference points for LBL/USBL/INS positioning of the surface platform. The system is effective in both shallow and deep water, with tracking capability down to 4,000 m.
System components
Gaps M7
High-performance USBL system with built-in Phins Compact C7 INS. Deployed on the surface platform, capable of operating in GNSS-denied conditions.
Canopus
Transponder deployed on the seabed as fixed acoustic reference for LBL and USBL positioning.
Delph SP
Simulation software used pre-deployment to optimize transponder placement and count, and to support reference transponder box-in.
Key benefits
Applications
Offshore construction
Cable and pipe laying
Rock dumping
Hydrographic and geophysical survey
Military and defense operations
GO DEEPER INTO THE TECHNICAL DETAILS
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