Optical Total Stations in Construction

Written by Paul F. Hahn

Created on Sunday, 06 February 2011 11:02

Most of the buzz the last ten years has been about RTK GPS (or GNSS)-based surveying and machine control.  This is for a good reason.  GNSS based systems can increase productivity dramatically.  They need no line of sight to make measurements and greatly increase operational range when compared to optical total stations.  However, the tried-and-true total station is still a workhorse for layout, topographic and as-built work.  We also see them employed as the instrument of choice for machine control in fine grading and paving applications.  Just as RTK GNSS systems have revolutionized the way we approach many applications, the total station has continued to evolve and has found new applications as well.

It all started in the early 1970’s when Zeiss and Geotronics introduced the first total stations.  Since then we have seen dramatic changes in their size, weight, range, accuracy and capabilities.  Some of the more notable advancements were the introduction of:

• On-board data collection systems with powerful microprocessors and coordinate geometry routines

• Direct Reflex, or prismless distance measurement capability

• Servo motor-driven instruments

• Auto-tracking instruments
• Robotic total stations for general surveying applications
• Auto-aiming instruments for monitoring and hydrographic applications
• Advanced Tracking Sensors (ATS) for machine control
• Imaging capabilities for documentation and other purposes
• Cameras for live video streaming
• The ability to perform surface scans
• Total stations that integrate or communicate with GNSS systems to provide a more robust solution

The above is a partial list and the capabilities continue to advance as do the application-based solutions.

One of the innovations that aided the advancement of these systems is the evolution of the data collector or field controller.  Herein resides incredible computing power which has advanced very rapidly.  The user interface of these devices has evolved as well from early, cryptic rows of numbers to full-color graphical systems with touch screens and internet connectivity. 

It is a hard call to say which advancement has had a greater effect on the overall productivity of the combined system of total stations and field controllers.  Total stations have come so far in the last 40 years but so have their controlling devices.  In combination, the system capabilities are truly amazing if one just looks back to the status quo of 20 years ago.  It was 1990 when the first robotic total station for every day surveying was introduced. About that time data collection had just become bullet-proof and reflectorless systems were starting to appear.  Many data collection programs were still running on hand held calculators and many had serious environmental issues and limited capabilities due to the available microprocessors and display screen technologies of the day. They have come a great distance in a relatively short time.

Now, I am starting to see a myriad of technologies being integrated into the top-of-the-line systems.  It is finally possible to realize new solutions to several challenging and difficult applications with just one instrument.  Take for example a new, state-of-the-art robotic total station coupled with an advanced field controller; it can:

• Measure without reflectors

• Be operated by one person in many applications

• Aim itself and track moving targets, at night or in the fog

• Measure incredibly long distances and do so in almost real-time

• Be integrated with or be aided by GNSS sensors

• Either at the rod or at the total station

  • Be used for machine control where highly accurate elevations are critical

  • Record video or digital photographs

  • Interact with the photo or video images for aiming, etc.

  • Be used for very precise monitoring projects

  • Be connected to the internet

  • Used in tunneling application

  • Used in railway application

  • Perform surface scanning while unmanned

  • Track moving objects or vehicles with very little latency due to synchronized angles and distances

  • Even utilize magnetic levitation to turn the instrument

  • Share data with other devices and other locations

  • Seldom ask for sick time or a day off and is happy to work in the dark

  • Utilize cell phone and radio telemetry to be remotely operated or position other devices and vehicles

  • Utilize base maps

  • Utilize daylight readable, color, touch screen displays (on-board and handheld) to improve the user interface

  • Integrate autofocus cameras, bar code readers, digital compasses, GPS, accelerometers, Wi-Fi, Bluetooth technology, voice prompts, audio recording  and more

  • Utilize various data storage devices and medium

  • Operate with amazing processor speed and massive storage capacity

I have been in the positioning industry since 1978 and have seen most of these incredible advances.  It has been very exciting and sometimes mind boggling to think of how far we have come so quickly.  Just like the first personal computers, the first total stations have come a long way.  Someone will probably say “it’s not your grandma’s total stations anymore” and they will be right. 

So, if your knowledge of what total stations are capable of and what applications they can be put to use in is more than a few years old, you may be missing out on some fantastic solutions.  Computing power and software is driving much of this, but there seems to be no limit to the designers’ imagination and ability to advance the systems by integrating new devices and technologies.  

More and more we see the modern total station used in construction layout, as-built’s and machine control.  They are finding new applications all the time.  Mechanical, electrical and plumbing contractors are even using them for layout and BIM purposes.  Interfaces are being developed for contractors in particular and software and operating systems are getting more user-friendly.  GNSS and total stations have different strengths and weaknesses and both belong in your technology toolbox.  Be sure to get up-to-date as both these technologies will impact your bottom line.

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