Subsea Navigation System

Subsea Navigation System

Underwater navigation systems are essential for the safe operation of UUVs (unmanned underwater vehicles) and AUVs (autonomous underwater vehicles) as well as manned ROVs.subsea navigation system Since seawater absorbs radio waves, these systems rely on acoustic signals and inertial sensors with real-time data fusion to allow vehicles to navigate where GNSS signals cannot reach.

Precision acoustic positioning is used for tracking and navigation of submarines, submarine rescue systems, marine archaeology, law enforcement and search and salvage operations.subsea navigation system It is also widely employed in oil and gas exploration and marine engineering projects. The loss of the American nuclear submarine USS Thresher on 10 April 1963, in a water depth of 2560m, led to the development of acoustic positioning systems. An acoustic short baseline system was installed on the bathyscaphe Trieste 1 and used to guide it through the debris field during a series of dives, ultimately allowing visual contact with the wreck to be made.

Two basic types of acoustic positioning systems exist: Short Baseline (SBL) and Long Baseline (LBL).subsea navigation system SBL acoustic positioning systems use a single surface vessel beacon/transponder to which the submersible is acoustically pinged and the resulting position information is used to fix the submersed vehicle’s position relative to that reference point. This is a relatively easy and fast to deploy solution with limited range, but provides high precision.

LBL positioning systems employ a fixed network of transponders on the sea floor that are acoustically pinged by the submersible.subsea navigation system This allows the system to compute the vehicle’s position by acoustic distance and direction measurement, and triangulation. These systems are more expensive and require a larger area of sea floor coverage, but provide very robust positioning performance with typically better than 1 m accuracy.

Another common technique is to pair acoustic positioning systems with DVLs (Doppler Velocity Logs) that measure the rate of change of position by estimating velocity relative to the sea floor. This type of system is known as a DVL-aided INS and it is useful for enabling advanced SLAM (Self Localization and Mapping) functionality.

Advanced Navigation offers a wide variety of high-performance, low power consumption MEMS and fibre-optic inertial sensor solutions to support UUV/ROV/AUV navigation, ranging from simple acoustic LBL and sparse LBL to fully autonomous SLAM systems. These systems are complemented by the highest-performing ring laser gyroscopes for a combination of position and velocity measurements with exceptional reliability.

Our advanced acoustic positioning systems are designed to be compact and lightweight for easier integration into smaller ROVs and AUVs as well as to minimize their effects on the vehicle’s control and movement. We also offer highly accurate GNSS-aided navigation systems that feature multi-frequency and multi-constellation support straight out of the box to meet the requirements of even the most demanding missions. For a complete solution, we also provide systems that integrate these advanced navigation aiding sensors with our highly precise inertial navigation systems. These are ideal for a variety of demanding applications such as pipeline inspection, maritime surveying and underwater construction.

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