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1

The efficiency of single base and network RTK for Structural Health Monitoring

Topal Güldane Oku, Akpinar Burak

Advances in Geodesy and Geoinformation

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2022

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Vol. 71, no. 2

art. no. e28, 2022

EN

With the developing technology and increasing construction, the importance of structural observations, which are of great significance in disaster management, has increased. Geodetic methods have been preferred in recent years due to their high accuracy and ease of use in Structural Health Monitoring (SHM) Surveys. In this study, harmonic oscillation tests have been carried out on a shake table to determine the usability of the Single Base and the Network Real-Time Kinematic (RTK) Global Navigation Satellite Systems (GNSS) method in SHM studies. It is aimed to determine the harmonic movements of different amplitudes and frequencies created by the shake table with 20 Hz multi-GNSS equipment. The amplitude and frequency values of the movements created using Fast Fourier Transform (FFT) and Time Series Analysis have been calculated. The precision of the analysis results has been determined by comparing the LVDT (Linear Variable Differential Transformer) data, which is the position sensor of the shake table, with the GNSS data. The advantages of the two RTK methods over each other have been determined using the calculated amplitude and frequency differences. As a result of all experiments, it has been determined that network and single base RTK GNSS methods effectively monitor structural behaviours and natural frequencies.

2

Study on the influence of stochastic properties of correction terms on the reliability of instantaneous Network RTK

Próchniewicz D.

Artificial Satellites : Journal of Planetary Geodesy

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2014

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Vol. 49, No. 1

1--19

EN

The reliability of precision GNSS positioning primarily depends on correct carrier-phase ambiguity resolution. An optimal estimation and correct validation of ambiguities necessitates a proper definition of mathematical positioning model. Of particular importance in the model definition is the taking into account of the atmospheric errors (ionospheric and tropospheric refraction) as well as orbital errors. The use of the network of reference stations in kinematic positioning, known as Network-based Real-Time Kinematic (Network RTK) solution, facilitates the modeling of such errors and their incorporation, in the form of correction terms, into the functional description of positioning model. Lowered accuracy of corrections, especially during atmospheric disturbances, results in the occurrence of unaccounted biases, the so-called residual errors. The taking into account of such errors in Network RTK positioning model is possible by incorporating the accuracy characteristics of the correction terms into the stochastic model of observations. In this paper we investigate the impact of the expansion of the stochastic model to include correction term variances on the reliability of the model solution. In particular the results of instantaneous solution that only utilizes a single epoch of GPS observations, is analyzed. Such a solution mode due to the low number of degrees of freedom is very sensitive to an inappropriate mathematical model definition. Thus the high level of the solution reliability is very difficult to achieve. Numerical tests performed for a test network located in mountain area during ionospheric disturbances allows to verify the described method for the poor measurement conditions. The results of the ambiguity resolution as well as the rover positioning accuracy shows that the proposed method of stochastic modeling can increase the reliability of instantaneous Network RTK performance.

3

Quality Indicator for Ionospheric Biases Interpolation in the Network RTK

Próchniewicz D., Walo J.

Reports on Geodesy

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2012

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z. 1/92

7--21

EN

This paper presents the methodology and performance of an ionospheric quality indicator in the Network RTK. A new index called Zenith Ionospheric Residual Interpolation Uncertainty, which is an extension of the existing indicator is proposed and evaluated using the reference station test network. The dataset used for this study was collected during ionospheric storm period in order to test the indicator during disturbed ionospheric conditions. The test results show that the proposed indicator provides a realistic prediction of ionospheric interpolation accuracy and can be used to predict the Network RTK performance at rover location.