Improving the accuracy of analog encoders via Kalman filtering

A new decoding method is presented for linear analog encoders enabling major improvements in both accuracy and resolution. A simulation study is used to demonstrate the performance improvement of the proposed method, demonstrating that the new method can generate position estimates with accuracy about three times better than that of standard methods. Moreover, in some special cases, the resulting position accuracy can reach subnanometer levels, thus enabling further size reduction in the semiconductor industry. The proposed algorithm also yields velocity estimates better by about two orders of magnitude than those obtained with standard methods. Copyright (C) 2003 IFAC.