Incremental Steps for Adopting Site Management & Positioning Solutions

Heavy equipment comes in many sizes, shapes and even colors. The applications for which they’re used are as varied. Positioning technology and site management tools should be designed with the flexibility to address these multifaceted combinations.

But where does a company start? With so many options, it can be challenging deciding what system to implement first. Below are suggestive incremental steps for your consideration.

Understand Basic Terms and Technologies
While there are many terms and technologies that comprise a positioning system, we are going to cover a few of the core technologies.

1. Global Positioning System (GPS) and Global Navigation Satellite System - GPS is a satellite system that is used to pinpoint the geographic location of a user’s receiver anywhere in the world. GPS is a US launched and maintained constellation while GNSS is a more broad term that encompasses all constellations, for example, GLONASS, Russia; Galileo, EU; BeiDou/Compass, China, etc. While positioning systems can use several intelligent sensor technologies to measure the articulation of a machine, GNSS is one of if not the most core and basic sensor. GNSS provides the basic position of a machine or asset that will “intersect” with a DTM offering relative position to the desired design. The accuracy of GNSS along can be many feet/meters so lets discuss the next term that tightens up the accuracy of GNSS along.
2. Real-Time Kinematic (RTK) - is a technique used to enhance the precision of positional data from GNSS. This is done by referencing the static position from a base station GNSS receiver and the kinematic (moving) data from a rover (such as a machine) and adjusting or correcting the rover positional data. This RTK correction is traditionally broadcast by a radio. RTK positions are +/- 1cm. For most applications including construction, land surveying and mining, an RTK correction is required to achieve desired and useful accuracies.
3. Digital Terrain Modeling (DTM) - Now that we have the position calculated and monitored for a given rover, we need relative position to a desired design. This reference is the digital terrain model. In the simplest sense, software subtracts the RTK position on the rover from that point on the DTM. If your application is grading, that difference is presented as a cut or fill differential (or on grade if they match).


Entry Point then Scale
The core technology that makes up a 3D machine guidance or control system exists in a man rover GNSS system with appropriate software. As described above, the intersection and vertical difference between existing and design surfaces offer basic cut/fill/on grade. of the same technology A few years ago, I wrote “The Most Affordable Entry Point into 3D Machine Control.” he logic still applies today.

“These 3D supervisor systems vary in their configurations but generally consist of an RTK GNSS receiver and a ruggedized field computer loaded with application centric software. These can be mounted in a pickup truck, ATV or on a GPS pole for use as a man rover/walk about. I have seen some of these systems also mounted in machines offering basic cut and fill, although the screens can be small and difficult to see. The rover does require a "correction" generally provided by a base station (static GNSS receiver) or from a 3rd party network provider.

The site supervisor rover prices can range from $13,000 to $18,000 plus the fee for using a network correction. If you are using a base station, add another $8,000 to $22,000 depending on configuration. These prices are much lower than a typical 3D machine control system, i.e., installed on excavators, dozers or graders, that can cost from $25,000 to $75,000 per machine depending on machine type, configuration and application.

The price makes the supervisor system a good first step.

While most traditional survey data collectors can accomplish many of the daily tasks performed by grade checkers and site managers, site supervisor systems have a more focused user interface. This makes it much simpler to learn and use. Cut/fill, simple slopes, elevation checks, line offsets, etc are upfront and center speaking the language of the grade contractor.

By taking this first step, you have embraced a new process that can save you money almost immediately. The first example that comes to mind is bid verification. Typically, a grading contractor receives a set of plans from an engineer with the existing terrain and the site design including approximate volume calculations. When the grading contractor bids the job, calculating earth quantities, the data is usually accepted to be accurate enough for estimating. Cost padding is the norm to cover any discrepancies. But by using a 3D supervisor system, the contractor can quickly drive or walk a site collecting data that will provide an accurate existing surface. This offers accuracies of 1/10th' giving a solid foundation for estimations.  The bids are tighter and avoiding potentially costly errors the contractor traditionally has to absorb. In short order, the system proves valuable as an affordable insurance policy. 



Another value for adopting a 3D supervisor system is being able to check grade for other machines. “This is like holding both ends of a tape,” a grade checker told me a few years back. Staking and collecting points is easy reducing dependencies on survey crews. This saves both time and money keeping the machines grading instead of waiting.
But perhaps the biggest benefit is the education and comfort using this technology.  Most of the supervisor systems work similar to the machine control systems so you have more of a business case and comfort level when you are ready to add a dozer or grader system.  If you purchased a base station with your supervisor system, the same base can broadcast corrections to an unlimited number of machines so you don’t have to repeat that cost.”

Once you are familiar with the basic concepts of 3D positioning with a supervisor system, the following is a quick list of further steps.

  • Machine Guidance elevation only (GNSS on a machine)
  • Machine Guidance with pitch, roll, yaw (adding axial sensors to various articulations)
  • Machine Control adds hydraulic controls automatically positioning the blade and other implements
  • Watch and warning zones can be as simple as added layers within the DTM. GNSS measures existing position and application software can “watch” or “warn” of avoidance zones
  • Production Analysis can be accomplished by taking the positional data or log files and post processing them with back office software that provides production data. Some of these calculations can be performed by the machines application software
  • Connecting Assets can be achieved by a wireless infrastructure; basic wifi and kinetic mesh are two examples. This infrastructure can provide proximity warnings between machines as well as communications and data transfers to the back office. Production analysis can also be calculated near real-time
  • Remote Monitoring offers value for site and safety managers. Processes such as manual or real-time dispatching is also possible


Summary

Traditional workflows and processes are fragmented. The reality that these processes are often performed by different subcontractors compounds the disconnect. Production and accuracy “leak” from all of these disconnected seams. Positioning and site connectivity offer huge opportunities to change these traditional workflows and enhance them with data rich management. But you have to start somewhere.

 

Additional References

1. Digitial Terrain Modeling-articles by:
-Marco Cecala http://www.machinecontrolonline.com/marco-cecala
-Chad Cooper http://www.machinecontrolonline.com/chad-cooper-bsce
-Ron Ciccarone http://www.machinecontrolonline.com/ron-ciccarone,-ls

2. GPS and RTK Technology
-Review of a must read book on GPS by Paul Hahn http://www.machinecontrolonline.com/paul-f-hahn/2556-review-of-a-must-read-gps-book
-Joe Sass http://www.machinecontrolonline.com/joe-sass

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