Multi-track prism technology explained
Tried and tested, Trimble’s MultiTrack technology has been on sites around the world for over 10 years and there is still simply nothing else on the market to rival it. This is because unlike other manufacturers, Trimble tracking does not rely purely on the reflectiveness of the target, it’s much more sophisticated than that.
The success of Trimble MultiTrack technology is a direct result of the introduction of robotic total stations (RTS), first introduced to us by Geodimeter (later to become a part of Trimble) over 25 years ago.
A total station may be called robotic if it is able automatically to follow a prism moving through 3D space. Key to this feature is the communication link between the total station and prism pole. All RTS, from all manufacturers, come equipped with servomotors for automatically rotating the instrument horizontally and vertically, and an Advanced Tracking Sensor (ATS) for tracking the prism, so how can we differentiate between the performance of one RTS and another?
When surveying with an RTS, it is more important than anything else to ensure reliable and robust target recognition. Typically on site we have lots of reflective objects like traffic signs, reflectors on safety vests or number plates and more likely than not, several prisms and targets are also in use. If we could measure only on “unidentified” (passive) targets, the surveyor would constantly be running the risk that those reflective objects would interfere with each other and cause a loss of target or a wrong target lock.
Step forward Trimble’s MultiTrack™ patented technology
Tried and tested, Trimble’s MultiTrack technology is 10 years old and there is simply nothing else on the market to rival it. This is because unlike other manufacturers, Trimble tracking does not rely purely on the reflectiveness of the target. Instead it uses a unique target ID system which identifies the prism using a modulated infrared light wave. Before measuring a point, Trimble Access field software can be set up to check the target ID and make sure the right prism is locked.
Up to eight active targets can operate simultaneously on the same site with no risk of tracking the wrong target, ensuring accuracy and completeness of work with no loss in productivity due to false target lock.
Some instruments on the market have a function called ‘self-learning’ in the form of a scanning function whereby you can do several scans to discount reflective surfaces. However, you need to cover the prism to exclude it from the scans and also nothing has to move during the process – an unrealistic situation on a busy site. This process therefore not only takes time but engenders a false sense of comfort because it works on the flawed principle that nothing within the environment moves. Where does that leave the surveyor surrounded by workers in high vis. clothing?
The ‘self-learning’ approach tells you what to exclude, the Trimble approach tells you what to include!
Trimble options include Trimble MultiTrack and ActiveTrack 360 Targets
The ActiveTrack 360 target was designed to provide a smaller, lightweight target for optical surveying utilising Trimble’s industry leading active tracking technology.
ActiveTrack 360 target is an active-only device and therefore contains no glass prisms. Eliminating the prisms provides for a smaller, lighter weight target, while maintaining robustness and measurement accuracy. It also offers Trimble’s new eBubble function – an electronic bubble displayed on the controller. This means you only have one place to look, which is especially useful when the pole bubble is hard to see. Connecting to the target via Bluetooth, allows the operator to see the plum of the pole on the handheld controller. This allows for better accuracy, especially when surveying in hard to reach areas or setting out using a short pole or point.
The Trimble MultiTrack target provides versatility to track both active and passive targets. Up to eight active targets can operate simultaneously on the same site with no risk of tracking the wrong target, ensuring accuracy and completeness of work with no loss in productivity due to false target lock.
In short, the Trimble MultiTrack target is suitable for use with all Trimble S-Series robotic total stations and provides fully coaxial passive and active tracking via an integrated 360° prism ring and 2 active 360° LED rings. The active LED rings support the selection of a unique ID to ensure that 8 different targets can be operated on a single site with full confidence that the correct target is always used.
Contact your local office if you would like to learn more about Trimble MultiTrack targets.
This article was originally posted on www.KorecGroup.com and has been reposted with permission.
