Localization Research Based on Special Fusion Method for Redundancy Ultrasonic Information

Abstract

This paper proposes a novel method to improve the accuracy of ultrasonic absolute localization. The characteristic and problem of ultrasonic absolute localization are analyzed and the insufficiency in existing methods is pointed out. Aiming at these questions, the special fusion method for redundancy ultrasonic information (SFMRUI) has been proposed. SFMRUI can well eliminate the error about times of flight (TOF) and can accurately calculate the wave lagging error. Moreover it can give an estimation of the measuring accuracy. Finally the experiment and the simulation have been performed, the experiment and the simulation results proved the SFMRUI law is effective and it can greatly improve the absolute localization accuracy. Index Terms -Ultrasonic absolute localization, Redundancy ultrasonic information, Times of flight, Wave lagging error

Deformation Monitoring of Metro Tunnel with a New Ultrasonic-Based System

“…The widely used least square method will yield relatively larger errors; thus, a new method by using redundant ultrasonic information (RUI) was proposed, which can overcome the limitation of the traditional method, as discussed above. The concept of the RUI method was put forward by Jiang et al [ 14 ]. The distance measured by ultrasonic wave propagation can be written as: where L n represents the measurement of the distance from the n th sensor, and ν represents the ultrasonic velocity in the measurement.…”

“…The measured t p has some errors due to the lagging errors of ultrasonic wave and electric circuits, and thus t p can be written as: where t c is the unit time of the measurement count, t’ cn is the counts of the n th receiver, t e is the wave lagging error which is caused by the insensitivity of the detection of the first coming receiving waves, and t d is the electric circuit lagging error. The electric circuit lagging error is negligible compared with the wave lagging error [ 14 ]. Thus, the error of the measured distances is: where e is the distance lagging error.…”

“…The frequency of the ultrasonic system is 40 kHz, and thus the wavelength is approximately 8.5 mm by taking ultrasonic velocity v = 340 m/s. In this study, the whole wave lagging error e should between 0 and 42.5 mm (5 λ ) [ 14 ]. When the wave lagging error of the ultrasonic receivers is consistent, the wave lagging error e can be determined and eliminated.…”