Using the signal-to-noise ratio of GPS records to detect motion of structures

Abstract

SUMMARYAlthough major breakthroughs have been achieved during the last decades in the use of GPS technology on Structural Health Monitoring, the mitigation of the biases and errors impeding its positioning accuracy remains a challenge. This paper tests an alternative approach that can increase the reliability of the GPS system in structural monitoring by using the spectral content of the signal-to-noise ratio (SNR) of GPS signals to detect frequencies of antenna vibrations. This approach suggests the potential of using SNR data analysis as a supplement to low-quality positioning solution or as a near real-time alert of excessive vibration proceeding the position solution calculation. Experiments, involving a GPS antenna subjected to vertical vibrations of 0.4-cm to 4.5-cm amplitude at a range of frequencies between 0.007 Hz and 1 Hz, examine the dynamic multipath induced SNR response corresponding to the antenna motion. Synchronised fluctuations in the SNR time series were observed to reflect the antenna motion and their spectral content to include the frequencies of motion. SNR records from the GPS monitoring of the Wilford suspension bridge were used to validate the SNR sensitivity to controlled vibrations of the bridge deck. The natural frequency of 1.64 Hz was extracted from SNR measurements using spectral analysis on a 6-mm amplitude vibration, and the frequency of the semi-static displacement (∼ 0.02 Hz) was revealed in the SNR records permitting, after appropriate filtering, the estimation of a few millimetre semi-static displacement from the GPS time series without the need for any other sensor.

Recent Advances of Structures Monitoring and Evaluation Using GPS-Time Series Monitoring Systems: A Review

“…Also, an adaptive filter is applied alone or integrated with Kalman filter to denoise the GPS measurements for structures [76]. Additionally, a high-pass and a low-pass Type I Chebyshev filter are used to estimate the behavior of structures based on GPS measurements [3,49]. Recently, with the development of GPS sampling frequency, the studies stated that GPS noises and errors can be eliminated using wavelet analysis [10,15,27].…”

“…Herein, it should be mentioned that some researchers introduced methods that can be used to detect the behavior of structures using noise and error performances. For example, Peppa et al [49] used the signal-to-noise ratio of GPS measurements to detect structures movements. Moreover, Souza and Negri [50] utilized the multipath effect to detect structure movements.…”

A Novel Dynamical Filter Based on Multi-Epochs Least-Squares to Integrate the Carrier Phase and Pseudorange Observation for GNSS Measurement

“…All of the technologies mentioned above require additional equipment and cost, except for carrier smoothing pseudorange technology that provides a limited improvement in the accuracy of SPP. Thus, forming a new type of GNSS observation based on integrating carrier phase observation and pseudorange is critical for GNSS (Global Navigation Satellite System) due to the ambiguity of the carrier phase and the high noise of the pseudorange [10]. The technology can absorb the advantages of the typical GNSS measurements, without ambiguity and high precision, and thereby forming a new pseudorange to aid cycle slip detection and repair [11], fixing ambiguity [12] and improving positioning accuracy [13].…”

Deflection distribution estimation of the main arch of arch bridges based on long-gauge fiber optic sensing technology

“…Some non-contact sensors have also been developed for direct measurement of structural displacement. For the non-contact sensor, Global Positioning System (GPS) is used for dynamic displacement measurement in two orthogonal directions (Chan and Xu, 2005); when the deformation is caused by an earthquake or typhoon or when the measured values are off by normal observation, the GPS is designed to identify the location (Fujino et al, 2000); Robotic Total Stations (RTSs) and Global Navigation Satellite System (GNSS) techniques, as an integrated manner, may provide efficient solutions for measuring three-dimensional (3D) displacements of structures (Peppa et al, 2018; Psimoulis and Stiros, 2013; Scaioni et al, 2018; Zhong et al, 2018); an unmanned aerial vehicle (UAV) with 3D digital image correlation was developed to monitor the health of bridges (Ellenberg et al, 2015; Park et al, 2015a, 2015b; Reagan et al, 2018; Ribeiro et al, 2014). The non-contact sensors overcome the disadvantages of contact sensors, but their application is still affected by many factors.…”