ELVAC SOLUTIONS s.r.o.

About 70 navigation devices are located in the territory of the Czech Republic, mainly in the surroundings of important airports (Prague, Ostrava, Brno, Karlovy Vary). These devices are concentrated in 37 technological cells, where in 11 cases there is no cable connection. The original solution used a special communication concentrator for every 8 devices with the concentrators being located in the control centre. For the connection with objects without cable connection, a leased connection by radio modems was used which was characterized by its low reliability. Due to the topology some devices were accessible indirectly only.

The main objective of the implementation of the new system for monitoring radio navigation devices was the replacement of the previously used unreliable transmission routes, removing the demand for special communication concentrators limiting the number of devices and the integration of one interface into the monitoring and control system used in technical halls. Due to new local topology such direct accessibility of communication with some devices, previously hidden behind a communication barrier comprised of more superior elements, is required.

Within the implementation of the project the central communication elements were replaced with the remote terminal units GSM RTU and NET RTU, in particular, the RTU 2.7 unit which originated from the expansion of the communication possibilities of the RTU 2 units already well established in applications of remote monitoring and control in the energy distribution sector. This enabled replacement of unreliable radio connection with communications through GPRS. Collection of data and its presentation are ensured by the RTUComCenter and CitectSCADA SW packages. New topology makes it possible to perform direct diagnostics of all devices, as well as direct and transparent communications with all elements. Due to the properties of RTU units and the implementation of specific SW there was the expansion of the possibilities of local gathering of data. Some of the actual supported devices are DME, VOR, NDB, LLZ, GP, MM, OM and FFM, applications used for the transparent mode are ADRACS and WINSW. A necessary precondition for reliable operation is also the checking of the correct function of individual parts of the monitoring system (servers, communication elements, RTU units). Key nodes of the system are redundant and work in the hot-standby backup mode. The final result of the whole event is the integration ofmonitoring and the control of radio navigation devices into the CMOS system associating all important technologies in the whole of the Czech Republic. Due to the use of open standards (SNMP) there is now available an easy exchange of data with other systems irrespective of which HW and SW platform they work on.

The main benefits of the new system for the monitoring of radio navigation devices are:

• Comprehensive availability of information about the status of the devices
• Monitored data is accessible anytime and anywhere. The only condition is network connectivity
• Open network architecture
• Use of communication standards enables to simply expand the system according to the actual demands of the user.
• Accessibility of distant points through GSM
• For monitoring of places which are within the accessibility of the data network GPRS technology which was used.
• Prediction of error statuses
• Uniform user interface for all monitored values
• Emulation of “cable” connection with all distant devices
• It is possible to use existing tools for the connection with remote devices
• Integrated authorization of access to particular interfaces
• Intelligent methods to maintain connections on slow lines (GPRS)
• High system reliability

RTUComCenter communication server on Windows platform
CitectSCADA for display of data and archiving, control and communication with superior systems
IEC EXCELLENT (redundant pairs) PC servers
NET-RTU unit with backup supply
GSM-RTU unit with backup supply