A Low-cost GPS-based Locomotive Tracking System for Steel Plant Applications
The most costly part of the LTS system is the communication link. Various means of wireless communication could be used: VHF/UHF radio links, cellular telephony, satellite based data communication systems such as ORBCOMMTM etc. The means of wireless communication can be used in two ways: a continuous or a polled setup.
In a polled setup, the central station requests position reports from the mobile units. When the position of a mobile unit is required, the central station sends out a request to that particular mobile unit, which replies to the central station with a position report. The central station is able to retrieve the position of all mobile units by means of two-way communication between the central station and the mobile units.
In a continuous setup, the mobile units send a position report to the central station on a regular basis. As a result, a recent position report of each mobile unit is available at the central station at any time. Only one-way communication, i.e. from the mobile units to the central station, is required. However, special care should be taken to prevent simultaneous transmissions. A solution to this problem could be based on the synchronisation in time of the mobile units by making additional use of their GPS receiver for accurate synchronisation.
Steel Plant System Requirements
The organisational structure of the traffic department at the Bokaro steel plant is depicted in Figure 2.
The head office takes major decisions such as locomotive allotment, repairs, fuelling etc. whereas the branch offices carry out the day-to-day operations. The branch offices give instructions with regard to the movement of the locomotives and assign them specific work.
As can be observed, the traffic control facilities are scattered around the steel plant, each catering to specific needs. For example, one group of locomotives may be working in the rolling mill area, another group in the blast furnace area and yet another group at the coke oven shops etc.
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