Hüseyin Pehlivan

High-rate Global Navigation Satellite System (GNSS) measurements can resolve dynamic motion, but detecting a spectral component does not identify its physical source. This study formulates Predictive Geometry-Normalized Structural Compatibility (PGNSC) as a post-detection, single-receiver test in which a model fitted without one satellite predicts the omitted complex time-differenced carrier-phase (TDCP) response through measured line-of-sight (LOS) geometry. PGNSC is characterised by the open TRANSFORM² TM3 campaign, comprising 50 Hz GNSS observations and 47 controlled sinusoidal events at 0.5 and 2 Hz with independent accelerometers and additional GNSS receivers. Conventional variometric processing recovered the imposed frequencies; PGNSC then tested whether the detected response generalised through LOS geometry. Because the six-GPS formulation has limited redundancy and high leverage, a GPS+Galileo sensitivity analysis examined numerical robustness. It reduced PRESS fragility and yielded campaign-internal event-versus-quiet area under the receiver operating characteristic curve (AUC) values of 0.959 at 0.5 Hz and 0.9998 at 2 Hz; separate dependence-aware checks on the historical expanded branch also retained strong separation. Algebraically, disturbances within the tested LOS-model space can preserve both fitted-model residuals and leave-one-satellite-out prediction errors. An exchangeable in-model-space verification accordingly produced chance-level discrimination (C_PAUC = 0.491; 95% CI, 0.457–0.524). C_P quantifies predictive LOS compatibility within the tested campaign; causal attribution requires independent physical evidence beyond LOS geometry.

A defensible local global navigation satellite system (GNSS) reference requires more than a precise network adjustment when small position or displacement changes are interpreted against that reference. This study evaluates a quality-audited realisation workflow for six rooftop control points observed in repeated 1 Hz static GNSS campaigns, with end-to-end documentary and computational traceability from raw observations and processing decisions to reference handling, stochastic modelling, adjustment, and external consistency. Within-session quality was assessed through ambiguity behaviour, residual diagnostics, and network closure, while repeated occupations and reference sensitivities were evaluated separately. After removal of a temporally localised C12 anomaly by a common trim, accepted loop closures ranged from 0.100 to 0.917 mm. Under a nominal 2.8 mm working component scale within a broader data-compatible stochastic family, the posterior variance factor was close to unity, and model-conditional ENU (East, North, Up) standard uncertainties were approximately 2.0–2.4 mm. Component-wise cross-campaign realisation differences were 3.42–6.61 mm after separate translation alignment of the March components, corresponding inter-triangle relative-vector uncertainties were 5.3–5.5 mm, and global positioning system (GPS)-only precise point positioning (PPP) showed centimeter-level external consistency. These results demonstrate that within-session consistency, reoccupation-inclusive assessment, model-conditional uncertainty, datum/reference sensitivity, and external consistency provide complementary, non-interchangeable evidence. The framework provides local reference infrastructure for downstream GNSS-based Earth-system interpretation without claiming direct estimation of Earth-system variables.

Traditional route optimization frameworks often suffer from “spatial blindness,” addressing the problem through abstract matrices devoid of geographical context. To address this fundamental methodological gap, this study proposes the Iterative Score Propagation Algorithm (ISPA), a transparent, GNN-inspired framework that reframes optimization as a holistic corridor problem. ISPA’s robustness and superiority were tested against established Multi-Criteria Decision-Making (MCDM) methods (WLC, TOPSIS, VIKOR) across three diverse engineering scenarios (Rural Highway, Pipeline, Trekking Trail) and two distinct weighting philosophies (Entropy and AHP). The holistic analysis reveals that ISPA achieves the highest final score (0.815) across all six test conditions, demonstrating both the highest overall mean performance (0.629) and the greatest stability (1.000). Furthermore, its flexible cost function successfully modeled unconventional objectives, such as a “climbing reward,” enabling a paradigm shift from cost minimization to experience maximization. ISPA’s superior performance stems from its structural advantage in contextualizing spatial data. This work introduces a new, spatially-aware approach that transforms route planning from a static calculation into a dynamic design and scenario analysis tool for planners and engineers.

Traditional route optimization frameworks often suffer from "spatial blindness," ad-dressing the problem through abstract matrices devoid of geographical context, which yields suboptimal solutions in complex landscapes. To address this fundamental methodological gap, this study proposes the Iterative Score Propagation Algorithm (ISPA), a transparent, GNN-inspired framework that reframes optimization from a set of isolated points to a holistic corridor problem. The robustness and superiority of ISPA were rigorously tested against established Multi-Criteria Decision-Making (MCDM) methods (WLC, TOPSIS, VIKOR). This comparative analysis was conducted across three diverse engineering scenarios—ranging from balanced engineering (rural high-way) and cost-centric optimization (pipeline) to experience maximization (trekking trail)—and under two distinct weighting philosophies (objective Entropy and subjec-tive AHP). The holistic analysis reveals that ISPA achieves the highest final score (0.815) across all six test conditions, demonstrating both the highest overall mean per-formance and the greatest stability. Furthermore, its flexible cost function successfully modeled unconventional objectives, such as a "climbing reward," showcasing a para-digm shift from cost minimization to experience maximization. We conclude that ISPA's superior performance stems from its structural advantage in contextualizing spatial data, rather than a dependency on any specific weighting scheme. Conse-quently, this work introduces not just a novel algorithm but a new, spatially-aware approach that transforms route planning from a static calculation into a dynamic de-sign and scenario analysis tool for planners and engineers.

The identification and removal of outliers in time series are important problems in numerous fields. In this paper, a novel method (BCP-HI) is proposed to enhance the accuracy of outlier detection in GNSS coordinate time series by combining Bayesian change point (BCP) analysis and the Hampel identifier (HI). By using BCP, change points (cps) in the time series are lidentified, and so the time series is divided into subsegments that have properties of a normal distribution. In each of these separated segments, outliers are detected using HI. Each data element identified as an outlier is corrected by a median filter of window size (w) to obtain the corrected signal. The BCP-HI method was tested on both simulated and real GNSS coordinate time series. Outliers from three different synthetic test datasets with different sampling frequencies and outlier amplitudes were detected with approximately 98% accuracy after processing. After this process, Signal-to-Noise Ratio (SNR) increased from 0.0084 to 10.8714 dB and Root Mean Square (RMS) decreased from 24 to 23 mm. Similarly, for real GNSS data, approximately 98% accuracy was achieved, with an increase in SNR from 0.0003 to 4.4082 dB and a decrease in RMS from 7.6 to 6.6 mm observed. In addition, the output signals after BCP-HI were examined graphically using Lomb–Scargle periodograms and it was observed that clearer power spectrum distributions emerged. When the input and output signals were examined using the Kolmogorov–Smirnov (KS) test, they were found to be statistically similar. These results indicate that the BCP-HI algorithm effectively removes outliers, and enhances processing accuracy and reliability, and improves signal quality.

In recent years, the continuously operating reference station – Turkey (CORS-TR) system has been widely used in engineering and cadastral work in Turkey due to ease of use, low cost, and national legislative requirements. In this study, long-term Network RTK (Real-time Kinematic) data were collected under 10°, 20°, 30° and 40° satellite views using a different approach from previous work. In order to evaluate the positioning performance of the system, the measurements were undertaken at different elevation angles (open, partially blocked and extremely blocked) and by considering three different correction techniques (FKP, VRS and MAC), and the results were evaluated in terms of repeatability. From the analysis of the data, it was understood that the performances of the three correction techniques were generally similar, and even in the case of a limited satellite view, the errors remained below 7 cm in all three techniques. However, when the 2D and 3D components were analyzed together, VRS technique showed better results than the other two techniques.

Bu çalışmada, yapıların bağıl deplasmanlarının belirlenmesinde, Robotik Total Station (RTS) ve Global Navigation Satellite System (GNSS) ölçümlerinin kullanılabilirliği araştırılmış ve deneysel verilerle analiz edilmiştir. Bu amaçla, İstanbul'da bulunan yüksek bir yapının gözlemlenebilir yükseklikte tepesine, iki adet GNSS alıcı anteni ve Total Station prisma reflektörleri monte edilmiştir. Bu iki gözlem noktasında, Gerçek Zamanlı GNSS ölçümleri ve yaklaşık 520 m uzaklıkta bulunan izleme noktalarından iki adet RTS kullanılarak açı-mesafe-zenit öçümleri, eş zamanlı olarak gerçekleştirilmiştir. Böylece, kayıt edilen bu gözlem serileri analiz edilerek yapının salınım genliklerinin belirlenmesi ve karşılaştırılması hedeflenmiştir. Analiz sonucunda şu sonuçlar elde edilmiştir; GNSS ölçümleri ile centimeter doğrulukla 0.5-1 cm genlikli salınımlar belirlemek mümkün olmuşken, RTS ölçümleri ile birkaç mm doğrulukla (2 mm) genlikli salınımlar kayıt edilebilmiş ancak yüksek frekanslı yerdeğiştirme değerleri belirlenememiştir. Bu sonuçlar, otomatize edilen Elektronik Totalstation'ların GNSS’e bir alternatif olarak yapı deplasmanlarının belirlenmesinde kullanılabilirliğini göstermiştir.

Observing the normal oscillations and the behaviours of high-engineering structures has become almost a necessity in terms of construction security and human health. For this purpose, an real-time kinematic GPS (NovAtel 400) and a tilt sensor (Leica Nivel20) were installed in a TV tower (220 m high) located in Istanbul, Turkey. The observation serials were recorded over a period of 9 days. All data-sets in X and Y directions were examined in the time domain and were analyzed using FFT€. The dominant frequency values (significant frequencies) were determined by comparing at the high- and low-frequency values. These dominant frequencies showed that the tower made 4- and 6-second short-period oscillations and 24- and 12-hour long-period oscillations. All the observation signals were re-created by the significant low-frequency values using the inverse Fourier transform. Thus, the motion model of the tower was determined over 9 days. In this study, the 24-hour and 12-hour periodic oscillations were defined that represent the behaviour of the tower in relation to the effect of the sun's radiation and the temperature changes.