Hybrid Autoencoder for Interference Detection in Raw GNSS Observations

Mascher, Karin; Laller, Stefan; Berglez, Philipp

doi:10.33012/2023.19369

Cited by 3 publications

(2 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Contrary to an expected linear time course [20,21], measures within a recent study focusing on changes of tibial acceleration to classify soccer-specific activities [28] showed a non-linear increase in accelerations in a maximal incremental running test, which was similar to the three-phase increase in ventilation as also supposed by Sheerin et al [21]. Therefore, three-dimensional acceleration measures from the tibia are suggested to distinguish between different phases of metabolism similar to standard physiological measures.…”

Section: Introductionmentioning

confidence: 85%

Accelerometer-Derived Intensity Thresholds Are Equivalent to Standard Ventilatory Thresholds in Incremental Running Exercise

Schützenhöfer,

Birnbaumer,

Hofmann

2023

Sports

View full text Add to dashboard Cite

Accelerometer cut-points are commonly used to prescribe the amount of physical activity, but this approach includes no individual performance measures. As running kinetics change with intensity, acceleration measurements may provide more individual information. Therefore, the aim was to determine two intensity thresholds from accelerometer measures. A total of 33 participants performed a maximal incremental running test with spirometric and acceleration (Axivity AX3) measures at the left and right tibia. Ventilatory equivalents (VE/VO2, VE/VCO2) were used to determine a first and second ventilatory threshold (VT1/VT2). A first and second accelerometer threshold (ACT1/ACT2) were determined within the same regions of interest from vector magnitude (|v| = √(ax2 + ay2 + az2). Accelerometer data from the tibia presented a three-phase increase with increasing speed. Speed at VT1/VT2 (7.82 ± 0.39/10.91 ± 0.87 km/h) was slightly but significantly lower compared to the speed at ACT1/ACT2 from the left (7.71 ± 0.35/10.62 ± 0.72 km/h) and right leg (7.79 ± 0.33/10.74 ± 0.77 km/h). Correlation analysis revealed a strong relationship between speed at thresholds determined from spriometric data or accelerations (r = 0.98; p < 0.001). It is therefore possible to determine accelerometer thresholds from tibia placement during a maximal incremental running test comparable to standard ventilatory thresholds.

show abstract

Section: Introductionmentioning

confidence: 85%

Accelerometer-Derived Intensity Thresholds Are Equivalent to Standard Ventilatory Thresholds in Incremental Running Exercise

Schützenhöfer,

Birnbaumer,

Hofmann

2023

Sports

View full text Add to dashboard Cite

show abstract

“…The RFI events before and after the COVID-19 situation also show different degrees of severe RFI events. In addition, machine learning on the C/N0 observations is utilized to monitor the GNSS interference (Mascher K et al 2023). Alternatively, the widespread ADS-B technology is utilized to detect rapid GNSS interferences on the aircraft approaches (Liu Z et al 2020(Liu Z et al , 2022.…”

Section: Introductionmentioning

confidence: 99%

Statistical Analysis and Effects of Radio Frequency Interference in GPS Signal Quality in Thailand

Sophan,

Supnithi,

Myint

et al. 2024

Preprint

View full text Add to dashboard Cite

The radio frequency interference (RFI) in global navigation satellite system (GNSS) signals has recently received much attention in the GNSS community because of frequent jamming issues. The carrier-to-noise density ratio (C/N0) is one of the common parameters to indicate the signal quality. In this work, we aim to analyze the occurrences of local RFI effects in areas surrounding the Suvarnabhumi International Airport as well as remote areas. Specifically, the percentage of RFI levels and raw C/N0 values are analyzed based on the modified RFI detection. The estimated RFI values are created from the raw C/N0 data, followed by the RFI levels generated by the empirical data. We validate the modified RFI detection by using the GNSS reference stations at the urban, suburban, and outside the capital city in Thailand. The user positioning errors with the high (severe) RFI levels are investigated based on the single point positioning (SPP) and real-time kinematics (RTK). From the experimental simulations, the high RFI levels at the urban are higher than those at the suburban. As expected, the statistical analysis covering COVID-19 (2019 to 2023) shows that the high RFI levels in June 2023 (post COVID-19) are more than those in June 2020 and 2021 (lockdown COVID-19) about twofold. Additionally, the SPP and RTK errors with the medium/high RFI levels have the error spikes in the centimeter to meter levels. The RTK performance with the fixed status can be affected and then returned to the float status as well.

show abstract