Systematic Error Elimination Using Additive Measurements and Combination of Two Low Cost IMSs

Inertial measuring systems (IMSs) enable determination of 3-D position and trajectory on a base of the actual measured acceleration and angular velocity. Measurements with the inertial sensors are influenced by errors from used sensors. Because of the principle of calculation of a position based on the recursive algorithm, there is an accumulation of systematic error, which causes a rapid decreasing of the position accuracy hand in hand with a measuring time. This paper deals with the suggestion of the model for data processing, which enables to eliminate systematic errors of sensors; thereby, the position accuracy is increased. For this purpose, an optical rotational-speed sensor was introduced and the additional measurement was realized with it in combination with the two IMSs located on the common baseline. Measurements from optical rotational-speed sensor were used in a combination with the accelerometers for their higher long-term accuracy. This combination enables to eliminate errors from the accelerometers even after the first integration process. Using the pair of IMSs located on the common baseline, the requirements (constraints) of the geometric relation of two coordinate systems of these IMSs were implemented into the model for data processing. These constraints were applied for correction of the position and orientation. As a part of the suggested model, an algorithm for identification of the dynamic phases was realized. This algorithm identified an actual dynamic phase of the system on a basis of the actual measured acceleration and angular velocity. This information was used for an adjustment of the processing model.