Product Review: Trimble S6 Total Station

It's not often that a new product can entice me to actually board a plane to go see it. From this chair one sees a lot of announcements, and manufacturers are quick to tout their product as truly new. The reality is often that, yes, there are some new properties with this or that new product, but maybe those properties are not all that dazzling once you've taken a closer look within the context of the product as a whole. But I did make the trip to Trimble's facility in Westminster, Colorado to take a good look at their new total station, the S6.

It does appear to me that Trimble's introduction of this top-of-the-line total station is something new indeed. The designers and developers went back a little further than is usual to find the starting point. That is, this unit addresses fundamental operating principles such as the technology for basics like aiming/pointing and the distance-measuring methodology itself. Let's see if we can break this package into understandable parts:


The S6 is modular, or scalable, if you prefer that term, in that it is available in three levels of capability and, of course, price. The most basic model, just referred to as "servo," uses the "magdrive" technology to turn the scope, can measure without a prism ("direct reflex"), and has all the collimation refinements and compensations we'll get to shortly. The next level up, "autolock," adds some more smartness to the instrument's internals, mostly centered around the unit's remembering where it was pointed. Again, more details about that later. The ultimate configuration would be the full robotic version. The developers have added some niceties on that end, too. It's all wireless, or "cable free." That particular feature only comes into play when we get to the top level—robotic.


This most basic configuration of the instrument has many of the refinements that encourage me to call the product "new." As do all the models, this basic one is driven with what Trimble calls "Magdrive." That term identifies the technology that drives the motion of the instrument. According to Trimble, it's the same technology used on the ultra-modern 300-mph trains now bursting on the scene overseas. Its basis is an arrangement of magnets and electrical coils which turn the instrument without metal-to-metal contact. And that difference is apparent pretty much immediately: this thing is quiet. It hardly makes a sound as it moves. As far as I know, and sometimes that's not all that far, this kind of motion driver is new.

"Direct Reflex" is Trimble's nomenclature for distance measurement without a prism or other reflector. That feature is standard with all models, as it is becoming industry-wide. By offering two distance measuring technologies (pulsed laser and phase-shift), this unit also boasts some pretty dazzling distance limits.

There are refinements in other basic elements: new ways to handle collimation errors and sophisticated compensators for both horizontal and vertical motions (called SurePoint). Although what we're talking about here is the most basic model of S6, the operator will almost certainly be impressed with the quiet movement—and the speed.

The instrument is fast. That is, when it is instructed to move (re-point), it moves very quickly. A simple example: there's a button to "change face," which is of course a command to turn the whole thing 180 degrees and plunge the telescope. According to the specifications of the unit, that exercise takes 3.2 seconds. That's turning at a rate of 115 degrees per second. For comparison, Trimble's next fastest gun takes just short of 10 seconds. Some other instruments clock in at the 8-9 second level.


With this addition, once the operator has pointed at backsight and foresight, he or she can invoke a command to turn, say, a round of angles, or a "set" if you prefer. So, if your procedures for a control traverse, for instance, include multiple pointings (which I hope they do), the repeat pointings can be made by the

instrument without operator intervention. I repeat, without operator intervention. The operator just stands by while this thing quietly and smoothly turns, changes face, and points and records observations in accordance with a recipe you've given it. My first question about that operation was, "Is it actually re-pointing at the targets as opposed to just going back to its remembered angle reading?" The answer, of course, was that, yes, the remembered angle was used, but only to give an approximation of sighting the target. The instrument then fine-tunes its aim at the actual target. Presumably you would thereby have very slight differences in the angular values.


This is the most advanced version of the S6, and it's advanced. Indeed, all the bells and whistles one could expect come on this unit. I won't belabor those; but one that I found particularly appealing was the audio feedback. If you've ever tried to run a one-person operation, you already know that one of the challenges is looking down at the display when trying to set a point. It sure seems neat to this surveyor to have a voice telling you to "move in two-tenths" or "move left two-tenths" and finally, "stake point."

As with so much of the really advanced equipment available these days, it is of prime importance to have an individual who is intelligent and highly motivated to make this system work at its fullest capability. Truth be told, operations can be portrayed as simple, but they're really not. Sorry.


Trimble has new software for the controllers/data collectors this unit needs. As I understand it, customers with, say, the TSCe, can get that software as part of their existing agreements. Then there is the new CU Controller, which I believe you need to get the voice feedback feature. All of the control units can connect with Trimble GPS receivers and other Trimble stations. And lots of other manufacturer's gear, according to the brochures.

Detailed pricing is not yet available, but a realistic look at the market and at the policies of various manufacturers tells us that this system would come in near the upper end of its category. I personally wouldn't expect it to be staggering. Let's look at the realities here: The S6 represents a serious investment, not just an expense. Once you reach the point of considering such an investment, you should probably be thinking beyond detailed dollars and cents.

As a principal of a private survey firm, I think I can safely say that this product is certainly worth a proper and thorough evaluation.

About the Author

  • Gerald L. McGray, RPLS
    Gerald was editor of the magazine from May 2004 to July 2006.

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