Policies for Sensor Planning
SANY D2.3.4 Specification of the Sensor Service Architecture V3 Doc.V3.1
Copyright © 2007-2009 SANY Consortium Page 188 of 233
integrity of the measurement data. The more complex form of monitoring consists if there are multiple sensors at the same time. An example is the video monitoring of a measurement station
in order to detect external factors that might affect the measurement process. Other monitoring scenarios could involve sensor service degradation. The main limitation in scenarios involving
mobile sensor networks is the power supply usually batteries of each individual network node. Depending on the network technology and geographic distribution of the nodes a failure of one
node might render the entire network unusable. In these cases a vital monitoring aspect is the node residual power.
Based on this information a sensor network administrator can make management decisions. Examples of such decisions include selection of network optimisation strategies e.g. adjusting
the network routing policies or node reporting sampling frequencies in order to reduce the power consumption of individual nodes or entire network. In the later scenario a good indication
of the residual power of a node is the power supply voltage. On a conceptual level as described in section 6.6.2 in the SensorSA Management Architecture this information constitutes the actual
observation data and should be handled the same way as any other observation coming from the sensor e.g. ambient air temperature or humidity. Therefore, the observation data about power
supply voltage shall be encoded as an observation according to the OGC Observation and Measurement model Cox, 2007. Consequently, the observation data can be stored and accessed
by means of an OGC Sensor Observation Service see section 8.2.2. Additionally the Sensor Alert Service see section 8.2.4 can be used to define event conditions and generate
notifications about the observation data, e.g. to send an e-mail notification to the sensor network administrator whenever a node battery voltage drops under a defined threshold.