10. Sensor Data Validation and Reconstruction

In a real water network, a telecontrol system must periodically acquire, store and validate sensor data to achieve accurate monitoring of the whole network in real time. For each sensor measurement, data are usually represented by one-dimensional time series. These values, known as raw data, need to be validated before further use to assure the reliability of the results obtained when using them. In real operation, problems affecting the communication system, lack of reliability of sensors or other inherent errors often arise, generating missing or false data during certain periods of time. These data must be detected and replaced by estimated data. Thus, it is important to provide the data system with procedures that can detect such problems and assist the user in monitoring and processing the incoming data. Data validation is an essential step to improve data reliability. The validated data represent measurements of the variables in the required form where unnecessary information from raw data has been removed. In this chapter, a methodology for data validation and reconstruction of sensor data collected from a water network is developed, taking into account not only spatial models, but also temporal models (time series of each sensor) and internal models of the several components in the local units (e.g., pumps, valves, flows, levels). The methodology is illustrated by means of its application to flow and level meters of the Catalonia Regional Water Network.