Your targets are an essential part of your laser position reference system.
How to position targets
DPOs with experience of laser sensors understand that the position of the target is of utmost importance, since a poorly located target can lead to degraded positioning or loss of target during operations.
DPOs working with Fanbeam and our training materials quickly learn how best to position targets, and the confidence indicators provided by the Fanbeam software, will show if confidence is low and targets may need repositioning. Fanbeam is a user-friendly reference position system, with simple principles of operation and intelligent software to support DPOs.
Key consideration when positioning a target are:
Ideally the target should be roughly the same height as the Fanbeam laser unit. This lessens the need for tilting and reduces the risk of target loss due to pitch and roll when working at very short range. Customers who have upgraded to the Fanbeam 5 will notice that the auto-tilt capabilities of Fanbeam 5 do significantly increase DPOs flexibility in this regard.
Fanbeam works optimally when the target is not too close to the laser unit. Operating over a very short range between target and laser unit (less than 10 m) is not recommended, and can slow operations.
Even when mounting is temporary, a robust mounting arrangement should be used. Physical loss of, or damage to a target could prevent operations. We therefore encourage customers to store spare targets on the vessel.
Targets must be mounted vertically. Incorrect target alignment will degrade performance.
The sensor depends on a clear line of sight to the target for optimum performance. While Fanbeam's sophisticated software helps identify and reject 'clutter', ensuring that the target is positioned away from locations where moving infrastructure or personnel can block the line of sight supports relaible operations.
All our targets are passive, simply reflecting the eye-safe class 1 laser beam emmitted from the laser unit. Nevertheless, making personnel on the platform or rig aware of what the targets are and what they are used for can prevent damage or movement of the targets.
Designed to work effectively
We've designed our laser sensor, reflective targets, human-machine interface (HMI) and software to work together. Understanding how targets contribute to the performance of the Fanbeam system helps customers complete Dynamic Positioning (DP) operations more quickly, and successfully.
Technical drawings, covering prisms and tube targets, mounting and positioning are available when you contact us, as well as support and pricing information.
Why targets are integral to the success of operations
When we introduced the Fanbeam system and associated reflective targets over 20 years ago, it offered an entirely new, accurate and reliable sensor for DP applications. While the system we provide today uses the latest laser technology and programming to deliver much more accurate and reliable positioning than was possible before, the principle of laser dynamic positioning, and the importance of target selection, remain the same.
The Fanbeam 5 sensor emits a very high-frequency laser pulse, invisible to the naked eye, over a 360° angular range. Quick-to-mount reflective targets, attached to moving or stationary platforms or vessels, return the laser pulse back to the sensor.
The sensor uses this returned pulse to measure the range and bearing of the laser unit from the targets, and our intelligent software then calculates relative position and heading giving Dynamic Positioning Operators (DPOs) accurate, time-of-flight information and communicates this to the DP system.
Quicker, problem-free dynamic positoning
A reflective target can in theory consist of any fixed reflective surface. However, problem-free performance demands powerful signal return, and our decades of experience working with DPOs has led us to recommend two different target types:
- Renishaw tube targets: For short-range use where cost is an issue.
- Renishaw prism targets: For optimum performance - even at long range.
We have seen these targets used for the full range of DP operations, on a large range of vessels, and know that both offer the following benefits:
- Speed and security of mounting: Fanbeam targets do not move once securely fitted.
- Flexibility of mounting: Fanbeam targets can be fitted on a permanent or temporary basis, with minimal maintenance required.
- Flexibility for operations: Fanbeam targets can be used on fixed structures or mobile structures.
- Precision engineering: For optimum performance with the Fanbeam sensor.
Prism cluster targets
Further to this, our marine-grade prism cluster targets enable customers to:
- quickly identify and lock on to targets
- track with confidence, and minimise target loss due to the very strong signal return delivered by our prism clusters
- reconfigure quickly and easily to extend angular coverage, giving flexibility for a range of operations
- enjoy a long lifetime, with less maintenance
- use Fanbeam over a long range of 2,000 m, beyond the installation 500 m exclusion zone
Configurable targets, for complete flexibility
Our prism targets consist of an engineered 'tree', designed to allow customers to mount our marine-grade retro-reflective prisms in pairs, stacked vertically in offsets of precisely 45°. By changing the number and position of prisms (which is quick and easy to do, with no special tooling required), DPOs can optimise targets for different operations.
This simple solution allows DPOs to take into account the relative height of the vessel and the platform, as well as the bearing on approach, giving them complete flexibility. Our training manuals cover the topic in more detail, with drawings to support decision-making in the field.
All prism cluster arrangements are supplied in a transit case, allowing for safe and easy transport offshore and storage when not in use. A metal mounting arrangement is also supplied, which allows for simple attachment to a handrail.
Maintenance consists of a simple inspection to ensure that the prisms are clean and that the mounting arrangement has not come loose.
|Cluster type||Angular coverage|
|4-way prism cluster||105°|
|6-way prism cluster||150°|
|8-way prism cluster||195°|
|10-way prism cluster||240°|
|12-way prism cluster||285°|
|14-way prism cluster||330°|
|16-way prism cluster||360°|
Single prisms can be purchased individually to extend angular coverage of existing cluster or to replace any lost or damaged prisms.
Reflective tube targets
Our reflective tube targets are a good entry-level option for general short-range use, where the Fanbeam is only needed as a position reference in close range of the installation.
As with our prism clusters, our tube reflectors are engineered as best-in-class products, comprising of diamond-grade reflective tape wrapped in a vertical orientation on 1 m long aluminium tubes. It is our use of materials and the construction of the target that ensures a high-level of signal return to the laser unit. Nevertheless, no tube target can compete with the range offered by prisms, as their surface is not able to match the very strong signal return offered by prisms. Our tube targets are recommended from a 10 m minimum range to a maximum range of 150 m.
One-ton shackles at both ends of the tube allow for deployment by crane and for easy attachment to a handrail or other structure on the side of an offshore installation. Targets are sold in pairs, in a transit crate, for ease of storage and transport.
All tube targets require regular, simple maintenance to ensure that salt deposits do not build up, which can impair the reflective properties of the target.