Amira Global is hosting a Spatial Science in Resources: Challenges and Opportunities workshop tomorrow, December 3. In the lead-up to this exciting event, we asked QUT Research Fellow Dr Charles Wang about the advantages and challenges of precise positioning based on his experience with the SBAS test-bed. The project is a collaboration of QUT academics and Wenco International Mining with supports from FrontierSI and GA.

Please tell us a little bit about yourself and your research activities at QUT

I am a Research Fellow at QUT in the School of Computer Science. I have always worked in precise positing, looking at areas such as:

• how to improve the performance, accuracy, reliability, availability of the positioning solution
• how to improve the efficiency and affordability for mass market users – correction delivery
• what precise positioning brings to the emerging applications – environmental modelling and monitoring, Intelligent Transportation System (ITS), Industrial IoT and mobile phones.

You were involved in the SBAS test-bed with Wencomine, could you tell us about the project? What were the goals?

The project was predominantly looking into GNSS for mine vehicle tracking. It is widely adopted technology in surface mine operations for fleet management, mine safety and environment protection. The current solutions (Standalone GNSS positioning) had limitations such as vehicle position jumps (tens to hundreds of meters), outages and inability to separate/identify grouped vehicles. This generated lots of false positives (alarms) in vehicle safety collision detections.

The objectives of the trials and subsequent data analyses were to examine the benefits of the SBAS test-bed services over the standard GPS/GLONASS services in three major use cases:

• surface vehicle fleet management
• V2X surface mine safety operations
• selected optimal mine vehicle operations.

Was the project successful in achieving those goals? What were the drawbacks?

We successfully met our goals in a number of the following key areas:

• Trial-2 evaluated the benefits of SBAS L1 service for the existing Wenco terminal device (TREK-753) running low-cost U-blox LEA5S GPS chipset. It has been shown from both stationary and kinematic tests that the SBAS enabled solution provides marginal improvements in the horizontal direction and noticeable improvements in the vertical direction when compared with the standalone GNSS solution for low-cost system.
• Demonstrated the use of SBAS services for V2X safety operation by conducting analysis of warnings between two vehicles on multiple collision scenarios. The results have shown improvements in the SBAS solutions (particularly Precise Point Positioning or PPP) has helped in maintaining stable relative distances while parking side-by-side in challenging environments.
• Demonstrated improved Rise and Run matrix calculation, which is commonly used in contract mining for the horizontal and vertical distance travelled by haul trucks. The calculation based on standalone GNSS could have large discrepancy in the “Rise” distance travelled (up to four times) and 9.55% differences in the “Run” distance travelled compared to the reference solution (RTK). The SBAS solutions offer more accurate estimate of Rise and Run distances travelled, in particularly, PPP is considered to have the same accuracy as the RTK solution with differences less than 3% in vertical.

In terms of drawbacks, there were a couple of things that did not go to plan:

• Field installation and testing was restricted as it is an operating mine
• There is a limited number of GNSS receivers capable of the second generation Dual Frequency Multi Constellation (DFMC), SBAS as well as PPP
• The correction supports GPS and Galileo only. At the time of testing, the Galileo constellation was nowhere near the full operational capability. We would probably get a better result if we do the test right now

Do you see any other applications for SBAS in the mining industry?

I believe the first one is autonomous haul truck and mining operation, as precise positioning can achieve accuracies up to 10cm. The second is predictive maintenance. Instead of vehicles coming back on fixed schedules, sensors and location tracking can result in the vehicles returning for maintenance only when required. Finally, if staff are fitted with personal tracking devices there is increased onsite safety.

What work needs to be done to enable industry to make the most of SBAS positioning in the future?

You cannot realise all the benefits simply by switching the SBAS signals on, you have to look at the system as a whole. Apart from the SBAS corrections and positioning solutions, you have to look at hardware and software implementations. In our project, Wencomine has developed collision avoidance tool based on extended GPS positioning and they had to make a lot of compromises due to the errors they found with the standalone positioning. Either they have to smooth things out to suppress the errors or make a lot of assumptions to factoring in tens of metres of positioning errors. A lot of these strategies have to be changed.

How could the resources industry benefit from the new technologies?

In a lot of use cases, higher positioning performance (accuracy, reliability and availability) leads to improvement in the efficiency and effectiveness or the workflow. These will improve the productivity and reduce the operational cost. In one of the SBAS economic benefit studies, the improved haul truck efficiency (as driver and operator place greater faith in safety mechanisms) resulted in a reduction in fuel and labour cost by allowing travel at higher speed. Overall, there is an estimated $1.6B in benefits to the resources sector over 30 years according to the EY report.

What excites you most about SBAS?

The free to air satellite correction broadcast, in particular PPP. Mines are often limited with internet and wi-fi connection, making correction delivery and tracking difficult.

What potential drawbacks do you see with SBAS

There is a lack of DFMC and PPP enabled receivers, especially low-cost. For instance, you could not use a professional-grade receiver for onsite personnel safety as the cost and size is too great. There is also a PPP convergence time – between 10 minutes and one hour – that may be an issue in some cases.