Wavelet Filtering of MEMS Inertial Measurement Unit for Autonomous Latitude Determination

For the position latitude autonomous determination it is necessary to have an inertial measurement unit (IMU) with triad gyroscopes and triad accelerometers. The output signals of MEMS gyroscopes and accelerometers have significant noise components. The wavelet transforms for the filtering of MEMS accelerometers and gyroscopes out-put signals for accuracy increasing of the position latitude autonomous determination was conducted. The autonomous latitude determination efficiency IMU on the basis of MEMS gyroscope and accelerometers has been experimentally confirmed. The projections of the Earth's angular rate and gravitational acceleration were obtained from the MEMS IMU. After that, the signals of the IMU gyroscopes and accelerometers were filtered, using the wavelet ‘Dobechie’ in decomposition and averaged. These signals were used in a computational algorithm to determine the latitude. The results showed that wavelet de-noising reduced computation error by almost twice.