Global Positioning System Reference
In-Depth Information
Diff. (cm)
Fig. 6. Surface plot of the height differences
7.2 Using RTK GPS for remotely monitoring and controlling machine automation
The use of Real-time GNSS positioning for machine automation can enhance its productivity
and functionality. Real-time GNSS positioning can provide cm accuracy, facilitating high
performance and output for machines that require positioning data. The Supervisory
Control and Data Acquisition (SCADA) is a good example for supporting a field automated
system. Having real-time accurate GNSS positioning information as an input to the SCADA
system gives a lot of opportunities to develop many solutions for planning, design,
construction and monitoring field operations that require precise positioning.
An automated machine such as a field tractor, excavator, or a driller can be automatically
operated, unmanned and fully remotely monitored and controlled. The machine can be
controlled by the analogue and digital outputs from a Remote Terminal Unit (RTU). The
RTU can have preloaded Programmable Logic Control (PLC) software that activates the
outputs according to the field inputs from the machine primary sensors as well as the real-
time accurate coordinates fed from a GNSS unit receiving measurement corrections from a
NRTK centre. The field operations, events, logs and alarms can be fully remotely monitored
through a SCADA system. For the SDADA system programming software, standards such
as IEC1131-3 can be used, which is the international standard for controller programming
languages. It specifies the syntax, semantics and display for the PLC programming
languages. An open standard communication protocol such as Distributed Network
Protocol (DNP) can be used. DNP is a set of standards and interoperable communication
protocol used between companies in processing automation systems. These open source
standards and interoperable platforms will allow the system design to be implemented in
any of the industrial proven commercial SCADA systems.
The functionality and process automation of the system can be described in two scenarios.
In the first scenario, the machine can be operated in a semi-automated mode with online
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