SANY Sensors Anywhere

To help decision makers to assess and react to particular situations, an implementation architecture for a Decision Support Infrastructure has been designed based upon the SensorSA information models and services. It has the following main capabilities:

• Discovery of sensor data and related services
  
• Access to sensor observations from different providers
  
• Management of sensor resources
  
• Subscription to and visualisation of sensor generated events and alarms
  
• Execution of processing services acting on sensor data
  
• Visualisation of sensor data on geographic map, charts, and tables

One of the key aspects in decision support are the fusion processing services with their ability to predict, in time and in space, the values of observed phenomena. Along with socio-economic data these predictions may also be used for impact assessment. In the course of the SANY project, a web based multi-user Decision Support Infrastructure (Web portal) based on ESA Service Support Environment (SSE) platform has been implemented to perform the above mentioned tasks.

The Web services used by the Decision Support Infrastructure are part of the SensorSA. The Decision Support Infrastructure provides a number of off-the-shelf clients for these Web services. Most of the clients are highly generic and instances of these clients can easily be deployed by a registered service provider on the portal.

The generic usability of these clients is achieved by taking advantage of the service metadata that is available through the GetCapabilities operation and possibly other operations (e.g. DescribeProcess, DescribeTasking) exposed by these services in order to dynamically build the client input forms. All the generic clients supporting OGC compliant SWE services (i.e. SOS, SPS, SAS, and WNS) can be configured to use SOAP instead of pure HTTP to communicate with the server (service instance).

The generic SOS client supports several result models: two standard specialized result models for time series and point spatial coverage and a more generic self-described observation model. The generic SOS client takes advantage of the SensorSA Map and Diagram Service to display contours on the map. For SOS service instances storing fusion results, the generic SOS client is able to display uncertainty information (expressed in UncertML) as well as sampling surface information for multi-point and rectified grid coverages.

Clients are provided to subscribe to and receive events and alarms through various notification mechanisms: the OGC WNS service supports the notification to end users via a number of protocols (e.g. e-mail, SMS, etc) while the OASIS WS-Notification specifications support the notification to consumer services through an intermediate broker. The Decision Support Infrastructure includes a WS-Notification consumer that can be coupled with a WNS server and an Event Panel client to provide a very flexible notification infrastructure. All the Decision Support Infrastructure clients can be configured to transparently support access to secured services i.e. services whose access is controlled by a Policy Enforcement Point according to the SANY security architecture. The clients automatically collect the assertion information for all the identities of the user (multi-domain security) through the SAC Logic which accesses the corresponding Authentication servers. This information (SAML tokens) is inserted in the SOAP header of all the service operations performed by the client. The user’s identities are registered by him using the SAC client.