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GEOSS Compo nent and Service Registries
GEO Portal Standards and
Interoperability Forum
Users
GEOSS Standards and Interoperability R egistry
Standards Special
Arrangements Components
Registry Services
Registry GEOSS Clearinghouse
Community Catalogs
GEOSS Contributor
Compo nents Services
Figure 4-5: GEOSS Interoperability Process from GEOSS CAIR, 2007
The architectural requirements of GEOSS are in many ways similar to the architectural requirements encountered in GMES and INSPIRE e.g. system of systems. As a matter of
fact, as documented in The First 100 Steps to GEOSS document GEOSS 100S, 2007, both GMES and INSPIRE are expected to provide important EU contributions to GEOSS. The
document also highlights the contribution that some FP6 and FP7 EU projects, including ORCHESTRA and SANY, could make in support of building GEOSS.
4.5. Requirements of Sensor Networks
This section summarizes several common sensor network scenarios of WatsonKunz, 2007 and addresses the issues of network topology, communication, and information flow and
processing. The specific requirements form the overall design approaches implemented within SANY. A sensor network is hereby understood as a collection of sensors and processing
nodes in which information on properties observed by the sensors may be transferred and processed. A sensor network may be of an ad hoc nature. In this case communication links
andor nodes are not continually available or might change dynamically. An ad hoc sensor network is often, but not necessarily, based on wireless communication between nodes with
limited resources energy supply, processing power. It may include mobile sensors belonging to the network for a limited time or intermittently.
The different scenarios mainly distinguish stationary and mobile as well as wireless and wired sensors. These aspects are described in Table 4-1. They determine the adequacy of
communication patterns and information flows.
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No Scenario
Topology Communication
Information flow Graphic
1 Sensors and data logger
with fixed locations Wired sensor networks
with sensor nodes, data logger and central
computer systems Sensor localization
information provided externally
Sensor nodes communicate with data
logger No intra-sensor node
communication Wired connections;
high bandwidth Sensor nodes report
observation to data logger Data logger provides
necessary meta-information Data logger reports to central
computing system
2 Mobile sensors and fixed
or mobile data logger Mobile sensors with
onboard GPS or other localization option
Data logger mobile or fixed
Wireless link between sensor node and data
logger Energy restrictions;
bandwidth limitations Data transmission energy-
optimized Pre-processingtransfer ratio
important
3 Mobile sensors moving
in different sensor networks
Sensor nodes migrate across networks
boundaries Sensor nodes adapt to
data loggers dynamically
Central computing system needs to merge data from
mobile sensors
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4 Mobile sensor cluster on
vehicles e.g. on ships - block data transfer on
demand Sensor nodes and data
loggers mounted on mobile platforms
Platform devices not permanently connected
to central computing system
Massive transfer in short time periods
required Pre-processing important
5 Mobile earth observation
sensors satellite, airborne
Remotely observing sensors
Localization mainly calculated
Direct link between sensor and ground
segment Several providers may
provide access to data Raw data repository often not
accessible
6 Mobile sensors with
their own IP address Sensors directly
connected to the Internet Sensor node
unambiguously identified by IP address
Permanent access via Internet
Direct data flow between sensor and Internet node
Security settings by sensor owner
Table 4-1: Overview about Sensor Network Topologies
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4.6. User Requirements
