Hardware Review: Trimble VX Spatial Station
Professional Surveyor Magazine - August 2012
If you’ve purchased any equipment similar to Trimble
’s VX Spatial Station lately, you know that it’s a bit like Christmas morning when the gear comes in. When the gear arrived at PSM, I got a message that the office was full of boxes—and trust me, they weren’t kidding. To perform this review I needed everything from the legs up, and Trimble was gracious in providing a full complement of equipment.
To wrap things up into one short, simple statement, I’ll steal a phrase not usually associated with surveying: The VX is one slick piece of kit. And, while we’re here, I’ll mention one other thing: Working with this instrument has spurred some thoughts that I’ll share with you later, though they don’t quite fit the mold of a typical product review.
The VX is a robotic total station with scanning functionality, integrated GPS capability, and on-board video—pretty much “the works.” It looks and feels like a standard robotic instrument; however, one immediate clue about the design and intended use of the VX is revealed on Trimble’s website. The VX is grouped not with the total stations but in the spatial imaging section, alongside their full-fledged FX and CX laser scanners.
The scanning feature was also highlighted by Alan Dragoo, at the time a sales rep with my local Trimble dealer, Keystone Precision Products. I am grateful to Alan for the time he spent with me, not only showing me the ropes with the instrument but also setting up accompanying software on my laptop. Alan also introduced me to a simple, yet very helpful, little piece of software called Remote Display Control. This is a basic utility that allows you to connect a Windows CE or mobile device, such as the Trimble Survey Controller 3 (TSC3), to a PC (more on this later, too).
Nuts & Bolts
As you can see from the photos, the VX is built on the “chassis” of the S6/S8 total stations, sharing colors, form factor, and many of the same internal components. The VX has all the standard specs and features you would expect from a high-end total station, and then some.
According to the specifications certificate included with the unit (a nice feature), the VX has an angle accuracy (DIN 18723) of 1”. The EDM operates in both prism and “DR” (direct reflex, or prismless) modes; the RMSE spec for both is 2 mm + 2 ppm. With a prism, distance measurement ranges from 0.2 m to 2,500 m; around my area we don’t take too many shots at a range of 8,000 feet—particularly to a single prism—but I suppose it’s nice to know you could. Prismless distances range from 1 m to a maximum of 1,300 m to a 90% reflective surface. A quick review of the specs for similar types of instruments shows the VX to be comparable (or superior) in these areas.
I think much can be determined from a simple sensory response to an object. The VX looks and feels solid and well-crafted; one would expect no less from a high-end instrument. The instrument feels substantial in the hand, but not too heavy. At roughly 11.5 pounds, its weight equals that of the S8 and is comparable to other high-end robotics. And, from what I could determine, the VX compares very favorably to at least one other similar instrument on the market. And let’s face it, for those one-man crews out there, size and weight can be crucial.
The VX uses their proprietary MagDrive system that was introduced with the S6 and is now fairly commonplace on Trimble instruments. I haven’t used a MagDrive instrument in day-to-day practice, but I’ve seen them operate firsthand and have been impressed with their quick, quiet, and smooth movement. Having been on the market for several years and offered with 1” accuracy on the VX, this technology has seemingly proven itself for most applications. In addition to the MagDrive horizontal and vertical motions, the optical focusing is servo-driven, as well.
Generally speaking, there are two methods of prism-tracking used with robotic systems: passive and active. A passive system essentially tracks any standard prism, whereas an active system makes use of some type of transmitter or diode array, at the rod, to assist the instrument in maintaining lock on the target. Trimble S-series and VX instruments can track either passive or active targets.
Figure 1 shows Trimble’s active target, viewed from the bottom. Visible at left is the rechargeable battery (slightly larger than a 9-volt, charges in the same dock as the instrument batteries); at right is the power switch/channel selector (eight available channels). A series of small, circular prisms encircles the top, constituting a 360-degree prism.
Above and below the prisms are a series of diodes that serve as the active tracking system (Figure 2). If you’re familiar with Trimble robots, this setup is reminiscent of that used on the 5600. The top cap can also be removed to allow mounting of a GPS antenna for what Trimble calls “Integrated Surveying.”
The VX case is also well designed (Figure 3). The case opens at the top, and the instrument is stored vertically. The top itself is angled, which seemed a bit unusual at first but does allow easy access to the compartmentalized interior (stability can be an issue on uneven ground). Slots/spaces are provided for the usual tool set, manual, cover, and batteries, as well as the prism (visible at left in the case). Other handy features are the built-in straps and padded side cover that can be used for backpack-style carrying and tucked away when not in use. This is a good example of the design of this as a “system,” oriented for use by one-man crews.
Thinking back to my experience with scanners a few years ago, one of the goals—if not the Holy Grail—of some manufacturers was to integrate scanners with conventional surveying equipment and procedures. That process has been occurring steadily over the intervening years. Indeed, as can be seen with the latest breed of imaging/scanning total stations from several major manufacturers, including the VX, conventional survey instruments are steadily making inroads toward scanning from the other direction.
And although scanning is steadily becoming more of a standard surveying activity, a fair number of surveyors are hesitant to jump fully into scanning or may not be able to justify the expense or need. For that population, an instrument such as the VX fits the bill perfectly. Using the on-board, real-time video display on the TSC3, scanning control is similar to that of full-blown scanners yet remains simple and straightforward. Because the instrument is a total station, controlled with surveying software, scanning becomes simply another part of the surveying process.
Although this is not a software review, it goes without saying that any piece of equipment with the capabilities of the VX relies heavily on its software. During the setup, Alan pointed out that Trimble strives to fully integrate their software across hardware and functionality. Based on the ease with which I picked up control of the VX (with no prior experience with the equipment or software), I have to say Trimble has succeeded on this front.
Trimble’s field controller software has evolved over the years, and the current version of Access seems smooth and intuitive. Moving between robotic and GPS and/or scanning is as simple as selecting which tool you want to use and continuing to survey (see the video demo of this on PSM’s website). And no matter what function you’re running (topo, stakeout, etc.), full access to the instrument controls is a single tap away.
Back at the office, conventional and GPS data can be processed with Trimble Business Center software (see a review of this package in the Sept 2011 issue). However, processing and manipulating scan data does require RealWorks software, which is also used with Trimble’s 3D scanners.
If you’re a power user (or just like to get your hands into something and tinker), Trimble offers a software development kit for Access. This provides the tools and support for adventurous users to create software applications customized to their needs. While most users will likely find that Access suits their needs out of the box, it’s nice to know these tools are out there if you want them. As for field operation, these screen captures from the TSC3 (below) provide a feel for the look and functionality of Trimble Access field software.
To paraphrase a cheesy commercial phrase, one could say about the VX: “It slices! It dices! It scans!” Surveying and the tools used in the profession are undergoing integration at a pace not likely seen before. And the VX represents the current state of the art of integrated survey technology. In the market for a new high-end robot? But maybe also toying with the idea of venturing into scanning but not ready to make the full leap? Either way, I can say with some confidence the VX is worth a close look.
Click below for two videos of TJ demonstrating the VX in the field.
Video - Part 1
Video - Part 2
TJ Frazier, LS, is a professional land surveyor in Mount Airy, Maryland.
Trimble Access Field Software Functionality
There are a couple of parts to this overall system that caught my attention in a rather unorthodox way. Here’s an idea about one.
I know there are people out there making efforts to raise awareness of the profession, both among students and the general public. I, personally and along with my local society chapter, seem to spend time in schools. If you’re like me, you get mixed results, in particular with students who have the attention spans of gnats.
There is always plenty in schools to connect with surveying: trig, geometry, technology, history, law. But we need something to catch their attention. And by now I’m sure you’ve deduced that the VX does just that (with just a little help).
Scanners are great at getting people’s attention. And any robot or GPS is high-tech and cool, but there’s still something missing. I have found that something to be the on-board video—together with the Remote Display Control utility mentioned earlier. With the TSC3 controlling the VX running the display utility and connected to an LCD projector, everyone in the class or group—I’ve even done lecture halls in front of 100 high school students—can now see exactly what the instrument is doing.
The robotic movement of the gun usually gets some “ooh and aahs,” but when the entire group can see exactly what the instrument sees and what’s on the controller, in real time, it holds their attention for much longer and makes it much easier to connect.
I don’t expect anyone to run out and pick up a VX just for school and group presentations, but if you happen to have one it makes a great prop. And if you don’t, I’d venture to say there’s a Trimble dealer in your area that would be willing to donate some time to the cause.
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