The MUTIS project has tested three satellite mobile systems and the terrestrial GSM system for availability and message transfer delay on the Danube river on a round trip between Vienna and Constantia in the perspective of providing services for in-land waterways traffic.
The pilot project tests have measured the availability of the satellite and terrestrial signals between 99.98% for GSM and 79% (for Thuraya) and a mean message delay between 12s (for GSM) and 184s (for IRIDIUM).
Transport management related river information services have communication requirements that are less demanding compared to the ones of traffic management related services. The amount of data that has to be exchanged is much lower and there is no urgent need for high actuality or availability since these services are not safety related. Therefore, a higher transmission delay can be accepted. The transferred data concerns in most cases only one user (point to point). Thus, broadcast functionality is not necessary.
The entire traffic management related river information services are strongly linked to safety. Hence, strict requirements follow for information actuality (respectively transmission delay) and service availability. These requirements cannot be met by the satellite communication services nor by GSM.
- Fairway Information Services are based on a great amount of data that have to be spread to the users. Since broadcast functionality is not provided by satellite communication services it would be necessary to spread the data by addressed messaging which is very complex and costly.
- Tactical Traffic Images are based on the spreading of information between vessels. Since this data exchange takes place every 2 seconds it is necessary to transfer the data at high speed and with marginal latency times.
The communication systems under investigation can be utilised in the field of transport management related river information services. But the costs have to be borne in mind. Other technologies are able to deliver the same functionality and performance at lower costs. The big advantage of the satellite communication systems is that they are completely independent from landside infrastructure. They can even be used in areas with no land-based network because of the low quantity of users. One additional benefit of implementing satellite communication can be the equivalent cost for services on long transport routes (e.g. Danube) with calculable costs (e.g. roaming costs).
Despite their theoretical usability the satellite communication systems are not applicable due to a lack of appropriate terminal equipment. Since the original service provided via satellite communication was telephony, only mobile phones are available at the moment. These cannot be integrated into the ship equipment for an operational system. Therefore the development of terminal equipment with modem functionality and external antenna connector - as it is available for GSM - would be necessary to meet the needs and to attract the market.