3D GPS machine control is now a common sight across most major civil projects Australia-wide. Used widely across a huge array of machines, from scrapers to graders, excavators, wheel loaders and everything in between, GPS is a flexible and accurate solution that enables all plant across the site to get to grade as quickly as possible with minimal wasted material.

In this article we look at the following topics: 

• How does GPS work on heavy equipment? 
• Single, twin or dual GPS: which is right for your application? 
• GPS and GNSS – is there a difference? 
• GPS vs Total Station vs Laser: which one is better?
• Topcon GPS machine control options by machine type

Here are some examples of applications where GPS machine control can be used:

• Subdivisions
• Wetlands
• Bulk earthworks
• Carparks
• Industrial subdivision
• Sports fields
• Freeways
• Airports
• Rail
• Landfill
• Landscaping
• Golf courses
• Batters
• Sewer & drainage
• Gas lines
• Basements
• Footings & foundations
• Dredging

So, pretty much everything.

What is the difference between GPS and GNSS?

Technically, GPS is the abbreviated name for Global Positioning System, the United States’ satellite constellation. But it is only one satellite constellation out of an increasing number, including Russia’s GLONASS, China’s Beidou, Japan’s QZSS and India’s INSAT systems, which all vary in terms of their size and availability.

Although GPS is commonly used to refer to satellite-run technology generally, GNSS (Global Navigation Satellite System) is a more accurate term as it incorporates all satellites, in all constellations.

Long story short, they are 2 different terms people commonly use to describe the same thing: satellites in space that deliver positioning information to computers on Earth.  

Fun fact: Australia is a pretty great country as we know, but another thing that makes it great is that it is able to access more satellites, from more constellations, than any other country on the planet due to geographic position. So that makes GPS an even better option for many construction and infrastructure projects.

How does GPS work on a machine?

There are a number of different components that work together to give accurate positioning information of the machine’s blade/bucket location relative to the design it’s working to.

GPS antenna or antennas: mounted to the top of a mast on the machine’s blade, at the back of an excavator or even on the roof of the cab in some of the newer mastless machine control systems.

Machine sensors: depending on the machine and the application, these include tilt sensors, rotation sensors and mainfall sensors and together they deliver an accurate 3-dimensional position of the machine’s cutting edge using GNSS positioning information from all available satellites.  

Control box: a display unit mounted inside the cab of the machine to give the operator live information about where the machine is relative to where it needs to be based on the 3D design it’s working to. The difference between these positions is known as the cut/fill. Depending on whether you’re working with an automatic or manual (indicate) setup, the cut/fill can be sent through the machine’s hydraulics to automatically move the blade to the design.

Base station or RTK network: This provides an accurate cross-reference for the GPS antennas on the machine. Because the machine is in motion, it needs to continuously update its position information using the satellites. You’ve probably noticed your car GPS or your phone is only accurate to within a few metres when you’re on the move. That’s where a base station comes in: because it’s not moving its position is ‘fixed’ so it continuously talks to the satellites and the machine’s GPS to communicate where the machine actually is to within a few millimetres.

GPS Receiver: Located in the cab, the GPS receiver is the heart and soul  of the machine control system. It turns all the GPS data from the satellites and signals from the base station into a real position on the ground that is then paired with the machine sensor data to give the machine’s blade or bucket tip its true location

What’s the difference between single, twin or dual GPS machine control?

Single = one GPS antenna

Twin = two GPS antennas, mounted to the same mast using a diamond bracket

Dual = two GPS antennas, mounted to two separate masts

What are the pros and cons of single antenna GPS?

Single masts work well in many applications, but because this setup has only one 3D  position it is not able to keep track of the direction of the machine quickly and is not able to tell the orientation of the machine as it has no other points to tell where the rest of the machine is.

Single GPS machine control is unable to work in reverse, the machine must be moving forward for it to maintain accuracy.

If you’re working on a steep slope, for example, and the machine is crabbing, a single GPS setup may result in an elevation error because the machine is moving at an angle rather than forward.

What are the advantages of a twin GPS antenna machine control setup?

Two antennas mean two 3D positions, which enable the system to always know the direction (or heading) of the machine. Add a rotation sensor and the machine control system will know the blade orientation at the same time, to give greater accuracy.

In grading applications, a twin antenna setup really comes into its own. It allows the operator to roll the blade and still work at high accuracy, without the need of a slope sensor. A twin antenna setup also enables the operator to work in reverse or change direction quickly without losing accuracy.

Twin GPS gives more accurate elevation than either single or dual GPS, especially when working on changing mainfall grades. Twin combines an accurate position of where the blade is relevant to the machine, as well as where the machine is relative to the Earth’s surface, which means that it is extremely accurate even on steep slopes. It’s important to note that any errors in your calibration or setup will be magnified significantly when working on steeper slopes, so twin GPS gives the operator peace of mind that accuracy will remain consistent. 

Topcon is the only manufacturer to offer twin GPS machine control solutions. It is also fully compatible with other 3D and 2D positioning technology.

Why would you use a dual GPS antenna machine control setup?

Dual masts are most commonly seen on excavator machine control solutions. These machines, unlike most other plant on site, don’t move forwards and backwards while they work, the pivot instead. Putting a mast on the two back corners of the machine means the system always knows the position of the boom, because the boom and the tail of the machine always face the same way.

In grading applications, a dual mast setup eliminates the need for rotation, slope and mainfall sensors. It does this by placing an accurate 3D position at each end of the blade, so it always knows the position of the cutting edge and the direction of the blade.

Because the system focusses on the direction of the blade, rather than the direction of the machine, it allows operators to work to steep slopes without having to compute the position of the A-frame at all.

The only thing to note as a potential limitation of a dual mast system on a grader, is that unlike a single or twin setup, you cannot easily switch to other types of machine control technology such as laser, sonic tracker, or total-station controlled systems without first installing the rotation, slope and mainfall sensors. You also have to be careful when working on very steep slopes when the antennas might be at a greater angle from the sky and therefore unable to track as many satellites. 

When should you use GPS instead of laser, total station or sonic tracking technology?

GPS is a very versatile tool that lies at the heart of many 3D machine control solutions. It’s advantage is its flexibility, combined with its accuracy, particularly when it comes to Topcon systems which are designed to be multi-platform and multi-machine compatible.

Topcon GPS machine control gives you the option to:

• Easily swap gear between machines
• Scale up or scale down to suit the job – for example you might box out a subdivision with GPS but then you can switch to a sonic tracker to follow the kerb. Topcon lets you work with 2D or 3D technology without having to install a whole new system
• Combine GPS with other technology, including laser or prisms with a total station, to increase accuracy even further for final trim work

The only drawback to GPS is that for it to work accurately, you need access to open sky so the system can draw information from as many satellites as possible. If you’re working under dense tree coverage, in very built up areas or underground, laser, sonic tracking or total station based systems are the way to go.

Here’s a quick table to outline all the options for Topcon GPS machine control:

	Single GPS		Twin GPS		Dual GPS		MC²		MCMAX
	Auto	Indicate	Auto	Indicate	Auto	Indicate	Auto	Indicate	Auto	Indicate
Dozer	•	•	•	•	•	•	•	•	•	•
Grader	•	•	•	•	•	•	•	•
Excavator						•
Compactor	•	•	•	•	•	•
Scraper		•				•
Wheel Loader						•
Skid Steer	•	•	•	•	•	•	•	•
Surface Miner	•	•			•	•
Trencher	•	•			•	•
Crane/Cable Excavator						•
Drill						•
Tow Scraper		•				•
Light Truck		•

 

Whether you’re using a wheel loader, excavator, skid steer or telehandler, we have a range of hydraulic machine scales and on-board weighing solutions to ensure you optimise your loading and most importantly keep an accurate record of the types and quantities of material you have moved. 

Click here to jump to our table outlining the applications and features of our hydraulic machine scales

Wheel Loader Scales

Reduce wasted material and wear on your machines with RDS Loadmaster loader scale solutions. Choose from the industry-leading Loadmaster Alpha 100 system, which comes with full-featured options including reversing camera, on-board printer and the choice of a trade approved upgrade, or the economical Alpha 50 model with colour touchscreen, individual product targets to ensure correct loading and live last bucket ‘tip off’ at the pile or above the truck. 

• Static and dynamic weighing modes means the system can keep up with the machine and weigh on the lift
• Advanced oil temperature compensation on the Alpha 100 maintains accuracy throughout the day when the machine is idle, moving or working hard
• Ensures accurate record keeping, traceability and stock management – reduce waste and minimise risk to your business
• ISOSYNC software for the Alpha 100 model to communicate between the office and machines with sophisticated reporting tools

The Loadmaster Alpha 100 system is also suitable for use as forklift truck scales and reach stacker scales. 

Compact Loader Scales

Ideal for trailer loading, batch blending or check weighing, the Weighlog Alpha 10 solution offers modern touchscreen technology and a user-friendly interface for compact loader machines. 

• Set individual target loads to ensure correct loading 
• Large database storage for accurate records and QA requirements
• Load accumulation for up to 10 attachments for maximum flexibility 

The Weighlog Alpha 10 is also ideally suited for telehandler scales, skid steer scales and rigid dump truck scales.

Excavator Scales

For excavators, the Loadex 100 system is a comprehensive and full-featured solution that delivers unparalleled accuracy and reliability. Reduce your Chain of Responsibility risk and ensure you load the right material, the right way, with Loadex 100 excavator scales. 

• Dynamic weighing technology uses inclinometers and a mechanical sensor to guarantee accuracy no matter what the job
• Hydraulic oil temperature compensation maintains reliability even when the machine is idle, has been working for long periods or is just starting the day
• Target load and GPS product recognition
• Complex technology, in an easy-to-use, intuitive interface with large, full colour touchscreen

 

Here’s a quick table to outline all the options for RDS Loadmaster machine scales: 

APPLICATIONS	Loadmaster α100		Weighlog α10		Loadmaster α50		Loadex 100		Isosync
Check weighing	•		•		•		•
Vehicle loading	•		•		•		•
Pallet weighing	•		•		•		•
Batch/blending	•		•		•		•
Trade approved	•
Stock & customer management	•		•		•		•		•
Trailer weighing	•
FEATURES	Loadmaster α100		Weighlog α10		Loadmaster α50		Loadex 100		Isosync
Colour touchscreen	•		•		•		•
SQL database	•						•
XML data output	•		•		•		•
GPRS & WiFi connectivity	•						•		•
GPS product recognition	•						•
Reversing camera option	•						•
Overload warning	•		•		•		•
Overload logging	•		•				•		•
Live last bucket	•		•		•		•
Target weight	•		•		•		•
Load accumulation	auto/man		auto/man		auto/man		auto/man
Lift speed compensation	•		•		•		•
Slope compensation	•						•
Temperature compensation	•						•
Attachments	10		10		10		10
Printer option	•		•		•		•
Telemetry option	•						•
SD card data transfer			•		•
USB data transfer	•		•		•		•		•
Scanner/RFID tag input option	•
Accuracy (+/- %)	1%		2%		2%		3%

 

 

Hagstrom Drilling is on the cusp of completing 3 months’ worth of geotechnical drilling investigations as part of Sydney’s major Western Harbour Tunnel and Beaches Link project. As one of NSW’s priority infrastructure projects, this proposed large scale motorway is expected to deliver time savings of up to 45 minutes for motorists travelling from the Northern Beaches to Sydney’s CBD, North Sydney and the airport.

Underwater drilling in Australia’s busiest waterway brought unique challenges that required the team to operate 24 hours a day, seven days a week in order to meet the project deadlines and accommodate stringent operating restrictions. In busy shipping and recreational channels, working at night was often the only option.

Investigations were undertaken in Western Harbour and White Bay, the results of which will help refine the design and planning of the Western Harbour Tunnel. In what’s now becoming a congested space under the harbour with the existing Harbour Tunnel to the east of the Harbour Bridge, along with the upcoming Sydney Metro rail tunnel to its west, the Western Harbour Tunnel is planned further west still. Crossing underneath Sydney Harbour between Birchgrove and Waverton, the tunnel would connect with WestConnex at Rozelle and the Warringah Freeway at North Sydney.

Drill investigations were also conducted in Middle Harbour for the proposed Beaches Link tunnel, which would connect the Warringah Freeway with the Burnt Bridge Creek Deviation at Balgowlah under Middle Harbour.

Hagstrom Drilling is a Perth-based company with offices in Sydney and Melbourne, specialising in all forms of geotechnical, environmental, hydrogeological and exploration drilling, investigation and testing Australia-wide.

With a strong focus on innovation and utilisation of the most technically advanced drilling techniques, Hagstrom Drilling uses DGPS technology to precisely drill to a client’s specified locations and provide accurate on-site and drilling reports.

Working in water depths between 15 and 35 metres deep, the company used three drill rigs and jack up barges to drill up to 100 metres below the sea bed for this project.

“DGPS technology is critical to provide accuracy in these applications,” André Fuller, Hagstrom Drilling Operations Manager said. “Input from these drill investigations determines the tunnel boring requirements, so it is essential that we get A1 performance from the positioning technology.”

Mr Fuller explained that DGPS units are fitted to the drill masts to give accurate position, relocation and elevation information to the operating crews. “We are consistently achieving +/- 100 mm HRMS and VRMS accuracy and within 1 metre Easting and Northing, which is well within tolerance levels for this project,” he added.

Another requirement for the project was to utilise the NSW Continuously Operating Reference Station (CORS) RTK network, CORSnet, now a requirement on all major infrastructure projects in the state.

Position Partners’ local Sydney team was able to assist with the network connection via its AllDayRTK network, which includes full access to the CORSnet infrastructure along with other government-run and privately owned reference stations throughout Australia.

Mr Fuller said that technical support was also crucial to the project’s success. “Given the cost implications of any delays, it was important to ensure smooth operations as much as possible,” he said.

“Given the challenges of the job, Position Partners’ Sydney team were an instrumental in maintaining system performance and they were happy to be called on outside of business hours as required. That’s something we have valued over the years as our projects are nationwide and Position Partners has a local team in each state and territory so there are always people within close enough proximity,” he added.

With investigations almost complete and the project successfully managed within time and budget, Hagstrom Drilling’s team will soon be packing up and moving on to the next project.

We’re pleased to announce a new national 3D laser scanning team to provided dedicated support to customers wishing to introduce or expand the technology into their business.

Led by Paul Malatzky, Position Partners’ Market Development Manager for scanning solutions, alongside Ryan Kent who has been newly appointed as one of two Business Development Managers who will be based on the east coast, the national team will work with Position Partners’ local branches to offer application-specific expertise for all laser scanning projects and customer enquiries.

A certified engineering surveyor, Paul has extensive experience across cadastral, mining, engineering and offshore projects where he utilised terrestrial 3D laser scanning, mobile mapping and multibeam sonar scanning technology.

Ryan is also a qualified surveyor who has worked with Position Partners for eight years across both technical support and sales consultancy roles. Having focused on mass data capture solutions for some four years, including Remotely Piloted Aircraft Systems (RPAS) and laser scanning technology, Ryan has excellent knowledge at both a technical and commercial level.

Our national team supports a range of industry leading 3D laser scanning and mobile mapping solutions from highly respected global developers including Zoller and Frölich (Z+F), Topcon and most recently Teledyne Optech.