Improved kalman filters in process control systems

A control technique that enables the use of received process variable values in a Kalman filter based control scheme without the need to change the control algorithm includes a controller, such as a PID controller, and a Kalman filter, coupled to receive feedback in the form of, for example, process variable measurement signals from a process. The Kalman filter is configured to produce an estimate of the process variable value from slow or intermittent process feedback signals while providing a new process variable estimate to the controller during each of the controller execution cycles to enable the controller to produce a control signal used to control the process. The Kalman filter is also configured to compensate the process variable estimate for process noise with non-zero mean value that may be present in the process. The Kalman filter may apply this compensation to both continuously and intermittently received process variable values.