Advanced Galileo Navigation System for Asphalts Fleet Machines
Background & Objectives
Today’s asphalt road construction relies a great deal on the experience of the construction worker to optimally manage the truck fleets, operate the paver and steer the compactor. Any sub-optimal operation within this chain may lead to a reduction in road quality, resulting in reconstruction or a decreased lifespan, both of which are cost-intensive.
By removing or reducing these quality-influencing issues, the lifespan of road construction should be significantly increased. Reducing the cost of road maintenance, which is the greatest expense during a road’s life span, should be a major effect of this project next to the exploitation goals of the product.
Over 90% of the total road network has an asphalt surface and this product is 100% recyclable. In Europe approximately 340 million tons of asphalt are produced each year – 1 600 million tons worldwide. The federal government budget in Germany foresees €& 25.6 billion to cover investment in road building in 2009. Improved road quality can save €& 4.5 billion in repair costs each year in Europe.
Constant monitoring and control of parameters is significant for the quality and durability of the road. The decisive factor is to explore the process chain and with the extensive use of positioning data to evaluate the possibilities of improving each sub-process responsible for the road quality.
The signal concept of Galileo used for this application allows quasi-triple frequency tracking. This availability of more than the traditional dual-frequencies for RTK with the Galileo system allows for faster and more robust RTK solutions. The combination with GPS strengthens the system providing more available satellites. The EGNOS/EDAS involvement allows achieving meter/sub-meter positioning when using less-precision applications like the compactor pass counting system. Using EGNOS/EDAS for possible faster RTK initialisations will also be investigated.
In ASPHALT, a GNSS receiver based on a triple-frequency approach (E1, E5a, E5b) will be developed. The focus will be on a multi-band RTK antenna and the integration of a combined discrete RF frontend for all frequency bands, including a Digital Signal Processor. Moreover a RTK high-accuracy position solution exploiting the measurements on the three different frequency bands will be developed. In parallel, a PVT Interface to EGNOS/EDAS will be proposed to provide a reliable position solution. A designated filter will be implemented to combine the different position solutions with application sensors so as to provide a position that meets the application requirements.
The major technical innovations are layer thickness and evenness control over distance (in place of the time) and an asphalt fleet management system.
The objective of the project is to develop a system for machine control and fleet management on a construction site, which enables building roads of better quality and durability. A significant improvement of the process and final quality can be achieved with a mass flow of asphalt, the detailed optimisation of different machine control loops and quality-dependent measurement systems. The proposed improvements are based on positioning information.
On one side, a scalable, cost-precision optimised system for the real-time control of the position will be developed and tightly coupled with the machine control system. On the other side, a novel monitoring machine and control system will be worked out based on the availability of the position.
As an example of the application, the paver control system and a compactor pass counting system, including on-site compactor fleet management systems and temperature estimations, will be designed and demonstrated, and a concept for asphalt truck fleet management will be proposed.?
Further applications for compactor to paver co-operation, drilling machine positioning and mass movement for grader and milling machines will be investigated and taken into account while designing the system and its interfaces.
Work performed & results
The target market will be the road construction business.
The following prototypes are planned to be available and tested:
- pass counting system on a roller with a core temperature estimation;
- temperature scanning system on a paver;
- concept of the steering system on a paver based on a 3D line;
- novel evenness and thickness control on the paver, allowing +/- 4mm deviation over 10m in the thickness and +/- 2mm deviation over 10m in the evenness;
- mass-flow information exchange between the asphalt truck and the paver;
- Galileo-capable RTK multi-band antenna prototype;
- a functional hardware industrial prototype of the receiver;
- a functional RF frontend high-precision receiver;
- high-rate and low-latency RTK software;
- robust PVT software.
After successful tests, the control-over-distance approach and paver steering based on a 3D line will be considered for a patent.