Sensor measurement errors detection methods

Abstract

This paper studies the methods of gross errors identification of transducer measurements from hydro energetic building especially from dams. The transducer used in dams monitoring is read every day during the year. The obtained information with one transducer can be seen as the discreet answers of a system. The erroneous measurements appear as a large variation from normal characteristics. The correction methods are mainly based on digital signal processing and approximation function. This paper proposes three method of correction: digital low pass filter, adaptive filter and approximation function. For low pas filtering is used a FIR (Finite Impulse Response) filter with Hamming window. An FIR filter is always stable, realizable, and provides a linear phase response under specific condition. These characteristics recommend FIR filter many filter design. Ambient temperature is the cause of the physical parameter variation detected with transducer. For error correction is applied an adaptive filtering, using the desired response. The approximation method function is less exhaustive and is based on the velocity of variation of result data from day to day. The data which is not respecting these conditions is removed. These three methods are used to determine a maxim correlation between results signals and original signal.