Voyis has released the Perception XL, a new 4000m rated laser scanning WROV skid specifically designed for generating extremely detailed volumetric point cloud models.
The Perception XL enables the gathering of incredibly dense data that was previously unachievable at faster ROV speeds. This pre-configured module is capable of delivering highly accurate and precise data of the seafloor and subsea assets, from pipelines to historic wrecks, conducting deepwater laser survey mapping from ROVs.
The Perception XL WROV Dynamic Laser Scanning Skid alleviates the time consumption and unknown integration woes of piecemeal equipment integrations on deck or dockside. System offsets are pre-defined and fine-tuned in-factory prior to arriving at the customer’s facility, meaning there is no need to waste time patch-testing offshore, no complex system wiring or on-site splicing, and no need to worry about compatibility. The skid even comes equipped with its own multiplexer for a “plug and play” connection. As a bonus, the topside equipment is pre-wired in rack-mount cases.
The Perception XL combines proven commercial products from the Sonardyne Group of companies: Voyis, Sonardyne, and EIVA, to create a high precision all-in-one system for underwater dynamic 3D survey and analysis.
Point Cloud Data – Voyis’ Insight Pro
The Insight Pro, including both 4000 m and 6000 m depth rating options, was developed in 2017 and is a staple in the offshore industry for dynamic laser scanning projects. The system is used on surveys where extremely high resolution and accuracy is required to make educated decisions on the condition of subsea assets.
The subsea laser offers substantially more detail compared to sonar solutions because it is optically based, generating 2,048 points per laser profile, at a capture rate of 52 — 92 lines per second. Compared to photogrammetry, the laser can provide true details of the structure’s depth and damage, and generate models in shadowed areas, even when there are no defined features because models are built using the geometry of the laser line on the target.
In addition, the 3D laser model is generated in real-time, offering the ability to conduct data QC during survey operations. These capabilities allow users to own their survey with real-time processed models that offer details unobtainable with other subsea solutions.
The Deep Water Challenge: Positioning is required to build accurate models in deep water. In shallow waters surface position updates, usually from an Ultra-Short BaseLine (USBL) system are used, but highly precise deep water scanning can’t rely on surface position updates. Solutions include:
- a local Long BaseLine (LBL) array on the seabed
- a sparse LBL array in combination with a good inertial navigation system (INS)
- a very good INS
Optically-based sensors are subject to the refractive properties of the water. While this might be negligible at shallow depths in standard water conditions, at extreme depths, the index of refraction (IOR) of the water column has an even greater impact on system accuracy if using hard-set parameters based on near-surface calibrations. The Voyis Insight Pro accounts for the index of refraction by using CTD values to ensure consistent accuracy at extreme depths, temperatures, or changes in water density.
Positioning Data – Sonardyne’s SPRINT-Nav
The Perception XL comes with Sonardyne’s all-in-one, acoustic-inertial subsea navigation instrument for underwater vehicles, the SPRINT-Nav 500.
SPRINT-Nav’s tight coupling of a SPRINT INS, Syrinx DVL and pressure sensor, with individual beam-level aiding from the DVL, means optimal performance but also that the INS doesn’t suffer drift from DVL dropouts when it goes over obstacles on the seabed or a structure being mapped. Beam-level aiding means if one beam drops out, it doesn’t matter, bottom lock continues. That’s important when performing surveys over ground or objects prone to loss of bottom lock.
Data Collection, Processing, and Visualization – EIVA NaviSuite
EIVA NaviSuite enables the real-time amalgamation of the resulting subsea laser and navigation data. This utilizes the NaviPac, NaviScan, NaviEdit and NaviModel products in the following ways:
- NaviPac provides real-time positioning and navigation for surface and/or subsea vehicles.
- Calculated NaviPac positions are sent to NaviScan, which is used to record data from multiple sensors at output high data rates.
- NaviEdit allows users to analyze and edit sensor data in its raw form
- NaviModel enables visualization, interpretation and quality control the results
The Result – A New Deep-Rated Laser Scanning Skid
The combined result is a single plug-and-play deep-water rated system able to provide its users with extremely detailed volumetric point cloud models across vast survey areas. The Perception XL can complete repeatable survey work in the deep ocean, all without the hassle of offsets, wiring, and corrections.
This impressive solution can be used for projects such as:
- seabed characterization,
- subsea structure inspection,
- seabed scour monitoring,
- environmental modelling,
- coral mapping
- corrosion modelling
The deep-rated Voyis Perception XL WROV Dynamic Laser Scanning Skid offers a solution to fully georeferenced models or metrology in deep water environments, without the need for manual point cloud stitching