Dozertrak

The DOZERTRAK system uses a laser guided tracking theodolite or GPS to determine the position of a moving target attached to a dozer. The positional information is combined with other sensors and processed by an on-board computer to determine the position of the cutting edge of the blade.  The computer screen dynamically displays the dozer blade on a shaded perspective view of the design surface in real time. Operators can work day or night without the use of surveyors as they can at all times see the position of the blade in relation to the final required surface. Alternatively, the display can be monitored on-site and the dozer operator given instruction by radio.

DOZERTRAK can reduce the inefficiencies that are brought about by the operator relying on a third party to instruct him as to height or tolerances to the finished surfaces. The more complicated the final surface, the more inefficiency prevails, particularly in the rehabilitation of spoil heaps when working on undulating surfaces.

The system when applied to the mining industry will increase Australia's overseas competitiveness by increasing the efficiency of the mining process and reducing the cost of land rehabilitation. Additional domestic benefits will accrue through more efficient practices in road works, dam construction, laying of fibre optic cables and other general earth works. Specifically the applications relevant to the coal industry are:

• Reclamation of spoil heaps
• Removal of overburden
• Ripping and stripping of thin partings and seams
• Defining boundaries of coal products in stock piles
• Road construction
• Dam construction

Objectives

Earlier testing had confirmed the theoretical aspects of DOZERTRAK. Testing was now required of a fully functional prototype in the field to test the components and their integration as a system.

It was always recognised that the success of DOZERTRAK was dependent on the successful transfer of technology to the mining industry through acceptance of mine managers and machine operators. Office and surveying equipment on board the dozer had to withstand the rugged environment that earth moving machinery operates in. Specifically the objectives were:

• to build a fully functioning prototype of DOZERTRAK;
• to fit the prototype on a Dozer and put it to work;
• to identify modifications required for a commercial product;
• to identify requirements from the industry as to the specifications of the final product;
• to compare the Tracking Theodolite against an advanced GPS device;
• to investigate the ability if the Tracking Theodolite or GPS to track a target in real time;
• to ascertain the suitability of high tech equipment being used in the rugged environment that the earth moving industry has to work in;
• to evaluate the ease with which a Tracking Theodolite or GPS can communicate with a remote computer situated on earth moving equipment.

Conclusions

DOZERTRAK is well suited to rehabilitation work, even at this early stage, with current accuracy achieved.  Specific outcomes were:

• The system works and provides an easy to read and understand visual display for the dozer operator. 
• The accuracy obtained in the initial trials surpasses anything that is currently available for dynamic real-time operator assistance. 
• Operators quickly assimilated the method required to work with DOZERTRAK and showed great enthusiasm towards the concept and application. 
• A dynamic accuracy of + / - 150mm recorded. 
• Tighter accuracy's are achievable with modifications to the tracking device and subsequent software changes. 
• DOZERTRAK will have an economic sound future in the recovery of coal. 
• Installation and set-up processes were verified and a better understanding of the procedures required to simplify these operations were gained. 
• There is insufficient room in the dozer cabin for the full computer and screen. The computer will have to be separated from the screen and mounted in a non intrusive position on the dozer. 
• Vibration levels within the dozer cabin indicate that either special computer mounts must be developed or that the computer hard discs be replaced by solid state ram.

This project outlines in broad terms a proposal to a mine site to participate in a R&D project that will have significant cost savings, whilst at the same time assist in the development of technology that will benefit the mining industry.

The proposal has significant capability to be altered to suit individual mine situations, provided the project aim can be achieved and the requirements of the R&D Tax Incentive scheme can be met.

This meant that by the early eighties, commercial interest in GPS begun to blossom. At this point the system was only partially implemented and so did not provide 100% coverage. As the USDOD experimented the system would be switched off or malfunction regularly.

Transit systems having set the pace for commercial and even personal leisure use of satellite navigation, GPS development expanded rapidly. By the mid eighties, an ever increasing range of commercial GPS receivers were becoming available.

These were still limited by the partial implementation of the system. Placement of satellites into orbit continued with a later generation of satellites. By 1990, although not fully implemented, the system was sufficiently reliable to make general commercial and even personal use viable.