The Seekable TN-1
The TN-1 is a passive-source electromagnetic (pEM) cable tracking system developed by Seekable to meet the operational and technical demands of today’s offshore power cable projects. It is engineered to operate in a wide range of environments including intertidal zones, shallow waters, and offshore deepwater conditions. The TN-1 introduces several key innovations that distinguish it from the current generation of cable tracking systems:
Model-Based Tracking: The core of the TN-1 system is a model-based approach that matches live sensor readings with a modelled magnetic field informed by a cable verification test on shore. This approach allows the system to produce more accurate position estimates than conventional raw signal-following methods.
Off-Axis Detection: The TN-1 is capable of tracking cables even when the sensor array is not directly above the cable up to 10-12 meters total distance. This is critical for operations in uneven terrain, fast currents, or where precise centering of the ROV or towfish is impractical.
Multi-Environment Adaptability: From beach landfalls to offshore trenches, the TN-1 is designed to adapt quickly to the specific needs of each project without requiring hardware reconfiguration. The TN-1 can be mounted on towed frames for marine surveys or on drones for intertidal or onshore surveys.
In its current form, TN-1 detects only energized (live or actively toned) cables. However, Seekable is actively developing an acoustic module to extend tracking capability to unpowered cables in future releases.
Survey speed: up to 4 knots when mounted on towed wings.
Sensors: Sensys 3-axis fluxgate magnetic sensors made in Europe.
Depth Rating & Durability: The standard TN-1 system is rated for operations up to 300 meters water depth. For deeper surveys, a specialized digitizer and sensor configuration is available, supporting deployments down to 3000 meters.
ROV, Towfish & UAV Integration: The TN-1 is typically deployed by rigid mounting in front of or behind an ROV, or towed behind a survey wing such as the EIVA ROTV (e.g., ScanFish). High-accuracy nonmagnetic heading as well as pitch and roll are required, which can be supplied by the carrying vehicle or provided by Seekable.
Additional properties
Data storage: in a HDF5 file.
Scaling factor: can be compensated for.
Post-processing: on multiple frequencies.
Multiple inversion models to choose from.
Data transmission via network interface
Simultaneously record magnetic data for UXO surveys.
Not disruptive to marine life.
