A system, a method, and a computer program for monitoring or controlling a field instrument in a pipeline, including receiving a plurality of process readings which originated from a plurality of remote terminal units that are distributed along a portion of the pipeline, analyzing the received plurality of process readings to determine a plurality of influencing process readings and a target process reading, assessing whether the target process reading includes bad data, and generating an estimated process reading or updating a parameter of a system model based on the plurality of influencing process readings and based on whether the target process reading includes bad data.