scholarly journals Estimating velocity from noisy GPS data for investigating the temporal variability of slope movements

2014 ◽  
Vol 2 (2) ◽  
pp. 1153-1192
Author(s):  
V. Wirz ◽  
S. Gruber ◽  
S. Gubler ◽  
R. S. Purves
Keyword(s):  
Temporal Variability ◽  
Time Window ◽  
Signal To Noise Ratio ◽  
Slope Instability ◽  
Gps Data ◽  
Factors Affecting ◽  
Slope Movements ◽  
Abstract Knowledge ◽  
Sensitivity Tests ◽  
Synthetic Time Series

Abstract. Knowledge of processes and factors affecting slope instability is essential for detecting and monitoring potentially hazardous slopes. Knowing the timing of acceleration or deceleration of slope movements can help to identify important controls and hence to increase our process understanding. For this methods to derive reliable velocity estimations are important. The aim of this study was to develop and test a method to derive velocities based on noisy GPS data of various movement patterns and variable signal-to-noise-ratio (SNR). Derived velocities represent reliable average velocities representative for a given period. The applied smoothing windows directly depends on the SNR of the data, which is modeled using Monte Carlo simulation. Hence, all obtained velocities have a SNR above a predefined threshold and for each velocity period the SNR is known, which helps to interpret the temporal variability. In sensitivity tests with synthetic time-series the method was compared to established methods to derive velocities based on GPS positions, including spline and Kernel regression smoothing. Those sensitivity tests clearly demonstrated that methods are required that adopt the time window to the underlying error of the position data. The presented method performs well, even for a high noise levels and variable SNR. Different methods were further applied to investigate the inter-annual variability of permafrost slope movements based on daily GPS- and inclinometer data. In the framework of the new method, we further analyzed the error caused by a rotation of the GPS mast (hmast = 1.5 m). If the tilting is higher than its uncertainty, the rotational movement can be separated and the direction of movement became more uniform. At one GPS station, more than 12% of the measured displacement at the antenna was caused by the rotation of the station.

Temporal variability of diverse mountain permafrost slope movements derived from multi-year daily GPS data, Mattertal, Switzerland

Landslides ◽  
2015 ◽  
Vol 13 (1) ◽  
pp. 67-83 ◽  
Author(s):  
Vanessa Wirz ◽  
Marten Geertsema ◽  
Stephan Gruber ◽  
Ross S. Purves
Keyword(s):  
Temporal Variability ◽  
Gps Data ◽  
Slope Movements ◽  
Mountain Permafrost

scholarly journals Unraveling Spatial and Temporal Heterogeneities of Very Slow Rock-Slope Deformations with Targeted DInSAR Analyses

2020 ◽  
Vol 12 (8) ◽  
pp. 1329 ◽  
Author(s):  
Chiara Crippa ◽  
Federico Franzosi ◽  
Mattia Zonca ◽  
Andrea Manconi ◽  
Giovanni B. Crosta ◽  
...  
Keyword(s):  
Rock Slope ◽  
Signal To Noise Ratio ◽  
Structural Heterogeneity ◽  
Linear Displacement ◽  
Slope Instability ◽  
Gps Data ◽  
Displacement Signal ◽  
Spatially Distributed ◽  
Multi Temporal ◽  
Displacement Patterns

Spaceborne radar interferometry is a powerful tool to characterize landslides at local and regional scales. However, its application to very slow rock slope deformations in alpine environments (displacement rates < 5 cm/year) remains challenging, mainly due to low signal to noise ratio, atmospheric disturbances, snow cover effects, and complexities resulting from heterogeneous displacement in space and time. Here we combine SqueeSARTM data, targeted multi-temporal baseline DInSAR, GPS data, and detailed field morpho-structural mapping, to unravel the kinematics, internal segmentation, and style of activity of the Mt. Mater deep-seated gravitational slope deformation (DSGSD) in Valle Spluga (Italy). We retrieve slope kinematics by performing 2D decomposition (2D InSAR) of SqueeSARTM products derived from Sentinel-1 data acquired in ascending and descending orbits. To achieve a spatially-distributed characterization of DSGSD displacement patterns and activity, we process Sentinel-1 A/B images (2016-2019) with increasing temporal baselines (ranging from 24-days to 1-year) and generate several multi-temporal interferograms. Unwrapped displacement maps are validated using ground-based GPS data. Interferograms derived with different temporal baselines reveal a strong kinematic and morpho-structural heterogeneity and outline nested rockslides and active sectors, that arise from the background displacement signal of the main DSGSD. Seasonal interferograms, supported by GPS displacement measurements, reveal non-linear displacement trends suggesting a complex response of different slope sectors to rainfall and snowmelt. Our analyses clearly outline a composite slope instability with different nested sectors possibly undergoing different evolutionary trends towards failure. The results herein outline the potential of a targeted use of DInSAR for the detailed investigation of very slow rock slope deformations in different geological and geomorphological settings.

scholarly journals Estimating velocity from noisy GPS data for investigating the temporal variability of slope movements

2014 ◽  
Vol 14 (9) ◽  
pp. 2503-2520 ◽  
Author(s):  
V. Wirz ◽  
J. Beutel ◽  
S. Gruber ◽  
S. Gubler ◽  
R. S. Purves
Keyword(s):  
Global Positioning System ◽  
Temporal Variability ◽  
Synthetic Data ◽  
Gps Data ◽  
Positioning System ◽  
Signal To Noise ◽  
Slope Movements ◽  
Global Positioning ◽  
System Data ◽  
Full Knowledge

Abstract. Detecting and monitoring of moving and potentially hazardous slopes requires reliable estimations of velocities. Separating any movement signal from measurement noise is crucial for understanding the temporal variability of slope movements and detecting changes in the movement regime, which may be important indicators of the process. Thus, methods capable of estimating velocity and its changes reliably are required. In this paper we develop and test a method for deriving velocities based on noisy GPS (Global Positioning System) data, suitable for various movement patterns and variable signal-to-noise-ratios (SNR). We tested this method on synthetic data, designed to mimic the characteristics of diverse processes, but where we have full knowledge of the underlying velocity patterns, before applying it to explore data collected.

scholarly journals Integration of Satellite InSAR with a Wireless Network of Geotechnical Sensors for Slope Monitoring in Urban Areas: The Pariana Landslide Case (Massa, Italy)

2021 ◽  
Vol 13 (13) ◽  
pp. 2534
Author(s):  
Andrea Ciampalini ◽  
Paolo Farina ◽  
Luca Lombardi ◽  
Massimiliano Nocentini ◽  
Veronica Taurino ◽  
...  
Keyword(s):  
Urban Areas ◽  
Temporal Evolution ◽  
Monitoring Program ◽  
Slope Instability ◽  
Time Data ◽  
Public Authorities ◽  
Slope Movements ◽  
Multi Temporal ◽  
Slow Moving ◽  
Slope Monitoring

Slow to extremely slow landslides in urban areas may cause severe damage to buildings and infrastructure that can lead to the evacuation of local populations in case of slope accelerations. Monitoring the spatial and temporal evolution of this type of natural hazard represents a major concern for the public authorities in charge of risk management. Pariana, a village with 400 residents located in the Apuan Alps (Massa, Tuscany, Italy), is an example of urban settlement where the population has long been forced to live with considerable slope instability. In the last 30 years, due to the slope movements associated with a slow-moving landslide that has affected a significant portion of the built-up area, several buildings have been damaged, including a school and the provincial road crossing the unstable area, leading to the need for an installation of a slope monitoring system with early warning capabilities, in parallel with the implementation of mitigation works. In this paper, we show how satellite multi-temporal interferometric synthetic aperture radar (MT-InSAR) data can be effectively used when coupled with a wireless sensor network made of several bar extensometers and a borehole inclinometer. In fact, thanks to their wide area coverage and opportunistic nature, satellite InSAR data allow one to clearly identify the spatial distribution of surface movements and their long-term temporal evolution. On the other hand, geotechnical sensors installed on specific elements at risk (e.g., private buildings, retaining walls, etc.), and collected through Wi-Fi dataloggers, provide near real-time data that can be used to identify sudden accelerations in slope movements, subsequently triggering alarms. The integration of those two-monitoring systems has been tested and assessed in Pariana. Results show how a hybrid slope monitoring program based on the two different technologies can be used to effectively monitor slow-moving landslides and to identify sudden accelerations and activate a response plan.

Insights to optimise marketing decisions on pig-grower farms

2019 ◽  
Vol 59 (6) ◽  
pp. 1126 ◽  
Author(s):  
S. V. Rodríguez-Sanchez ◽  
L. M. Pla-Aragones ◽  
R. De Castro
Keyword(s):  
Weight Control ◽  
Time Window ◽  
Programming Model ◽  
Transportation Cost ◽  
Management Policy ◽  
Mixed Integer ◽  
Factors Affecting ◽  
Pig Production ◽  
Marketing Policy ◽  
Feeding Program

Modern pig production in a vertically integrated company is a highly specialised and industrialised activity, requiring increasingly complex and critical decision-making. The present paper focuses on the decisions made on the pig-grower farms operating on an all-in–all-out management policy at the last stage of pig production. Based on a mixed-integer linear-programming model, an assessment for specific parameters to support marketing decisions on farms without individual weight control is made. The analysis of several key factors affecting the optimal marketing policy, such as transportation cost, when and how many pigs to deliver to the abattoir and weight homogeneity of the batch, served to gain insight into marketing decisions. The results confirmed that not just the feeding program, but also the grading price system, transportation and batch homogeneity have an enormous impact on the optimal marketing policy of fattening farms in a vertically integrated company. In addition, within the range of conditions considered, a time window of 4 weeks was deemed as optimal for delivering animals to the abattoir and the subsequent revenue was 15% higher than with traditional marketing rules.

Factors affecting spatial and temporal variability in material exchange between the Southern Everglades wetlands and Florida Bay (USA)

2003 ◽  
Vol 57 (5-6) ◽  
pp. 757-781 ◽  
Author(s):  
Martha A. Sutula ◽  
Brian C. Perez ◽  
Enrique Reyes ◽  
Daniel L. Childers ◽  
Steve Davis ◽  
...  
Keyword(s):  
Temporal Variability ◽  
Florida Bay ◽  
Spatial And Temporal Variability ◽  
Factors Affecting ◽  
Material Exchange

scholarly journals The 1998 Tatopani Landslide in the Kali Gandaki Valley of Western Nepal: cause and relation to mass rock creep

2000 ◽  
Vol 22 ◽  
Author(s):  
Hellmut R. Volk
Keyword(s):  
Slope Instability ◽  
Low Grade ◽  
Left Bank ◽  
Main Central Thrust ◽  
Slope Movements ◽  
Wedge Failure ◽  
Rock Avalanches ◽  
Rock Creep ◽  
Mass Rock ◽  
The Village

The village of Tatopani lies on a small gravel terrace in the middle reach of the Kali Gandaki River, along a narrow course of about 2 km in length. One kilometre south of the village, a major rockfall occurred recently in the region of the Lesser Himalaya, which is built up of low-grade metamorphic rocks of the Kuncha Group, consisting of a thick sequence of foliated phyllites and bedded quartzites as well as interlayering of both lithologies. The monoclinal structure of these metasedimentary rocks is clearly related to the general trend of the Nepal Himalaya near the Main Central Thrust (MCT): strike NW-SE 140- 150°, dip 25-45° NE. Besides a clear foliation in the phyllites (s1) parallel to the quartzite bedding (s0), four other discontinuities are also developed as steep joints (j1-j4). Two joint sets j1 and j2, both crossing each other and both acting in conjunction with the foliation (s1) as a shear plane, were responsible for the wedge failure of the Tatopani Landslide, which led to a rockfall and avalanche of about 400,000 cubic metres and dammed the river for about 72 hours. It is noteworthy that several other - strikingly similar but older - weathered wedge failure surfaces are exposed at various spots all over the same ridge, which is the spur-ridge dividing the Kali Gandaki River from the Gar Khela tributary. This visible slope instability evidenced by relatively small wedge failures is causally connected with a much larger mechanism, namely mass rock creep or "sagging"- a purely gravitational slope deformation. The repeatedly occurring wedge failures producing landslides (rockfalls and rock avalanches) are caused by extreme shear stress and deep-reaching joints and fissures during mass rock creep. Only the final trigger for landslides or rockfalls is provided by extreme and lengthy monsoon rainstorms, which reinforce the cleft-water pressure inside rock discontinuities and openings, especially along the impermeable interface of quartzites and phyllites (s0 =s1) at the base of the wedge failure. The right (western) bank above the village is morpho-dynamically active also through mass rock creep and “pushes” laterally against the river course. However, the kinematics of the rock slope is rather different because the foliation geometry is more important. The foliation dips obliquely towards the riverside and consequently has facilitated extremely slow large­ scale dip slope movements along quartzite-phyllite interfaces (s0) without any catastrophic danger. However, the creeping slope movements of thick quartzite: members caused a set of conjugate extension faults producing toppling at the distal slope margins. Rock avalanches from the spur-ridge on the eastern (left) bank of the Kali Gandaki River S of Tatopani will always remain a threat, especially when excessive seasonal rains increase the cleftwater pressure inside the invisibly slow creeping system of the steep bank in an extraordinary manner.

A Role for GPS Data in Qualitative Research

2014 ◽  
pp. 309-324
Author(s):  
Christoffel Venter ◽  
Nyasha Minora ◽  
Kory Shukrani ◽  
Jacques du Toit
Keyword(s):  
South Africa ◽  
Qualitative Research ◽  
Fear Of Crime ◽  
Gps Data ◽  
Factors Affecting ◽  
Walking Activity ◽  
Multi Method Approach ◽  
Gps Tracks ◽  
Adaptive Behaviours

This chapter describes the use of GPS in a multi-method approach to explore environmental factors affecting walking patterns in South Africa. Quantitative measures of walking activity are derived from multiday GPS tracks of a sample of people in three case study areas in Pretoria, South Africa. The data suggests that a significant amount of walking takes place across a range of neighbourhood types. The authors then describe a methodology that marries the strengths of GPS data—notably its detail and its suitability for visualisation—with the benefits of more open-ended qualitative research methods to obtain richer insights into the motivations behind the observed behaviours, and the extent to which these are related to built environment factors. A key finding is that personal security and fear of crime is a critically important factor driving both the perceptions and behaviour of pedestrians, especially women. Specific adaptive behaviours are observed that warrant further research.

scholarly journals Arrival-Time Detection in Wind-Speed Measurement: Wavelet Transform and Bayesian Information Criteria

Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 269 ◽  
Author(s):  
Wei Zhang ◽  
Zhipeng Li ◽  
Xuyang Gao ◽  
Yanjun Li ◽  
Yibing Shi
Keyword(s):  
Wavelet Transform ◽  
Wind Speed ◽  
Arrival Time ◽  
Time Window ◽  
Signal To Noise Ratio ◽  
Information Criteria ◽  
Echo Signal ◽  
Time Frequency ◽  
Ultrasonic Echo ◽  
Ultrasonic Anemometer

The time-difference method is a common one for measuring wind speed ultrasonically, and its core is the precise arrival-time determination of the ultrasonic echo signal. However, because of background noise and different types of ultrasonic sensors, it is difficult to measure the arrival time of the echo signal accurately in practice. In this paper, a method based on the wavelet transform (WT) and Bayesian information criteria (BIC) is proposed for determining the arrival time of the echo signal. First, the time-frequency distribution of the echo signal is obtained by using the determined WT and rough arrival time. After setting up a time window around the rough arrival time point, the BIC function is calculated in the time window, and the arrival time is determined by using the BIC function. The proposed method is tested in a wind tunnel with an ultrasonic anemometer. The experimental results show that, even in the low-signal-to-noise-ratio area, the deviation between mostly measured values and preset standard values is mostly within 5 μs, and the standard deviation of measured wind speed is within 0.2 m/s.

scholarly journals Supra-glacial debris cover changes in the Greater Caucasus from 1986 to 2014

2020 ◽  
Vol 14 (2) ◽  
pp. 585-598 ◽  
Author(s):  
Levan G. Tielidze ◽  
Tobias Bolch ◽  
Roger D. Wheate ◽  
Stanislav S. Kutuzov ◽  
Ivan I. Lavrentiev ◽  
...  
Keyword(s):  
High Resolution ◽  
Sea Level ◽  
Google Earth ◽  
Gps Data ◽  
Glacier Area ◽  
Greater Caucasus ◽  
Abstract Knowledge ◽  
Covered Area ◽  
Debris Cover ◽  
Automated Methods

Abstract. Knowledge of supra-glacial debris cover and its changes remain incomplete in the Greater Caucasus, in spite of recent glacier studies. Here we present data of supra-glacial debris cover for 659 glaciers across the Greater Caucasus based on Landsat and SPOT images from the years 1986, 2000 and 2014. We combined semi-automated methods for mapping the clean ice with manual digitization of debris-covered glacier parts and calculated supra-glacial debris-covered area as the residual between these two maps. The accuracy of the results was assessed by using high-resolution Google Earth imagery and GPS data for selected glaciers. From 1986 to 2014, the total glacier area decreased from 691.5±29.0 to 590.0±25.8 km2 (15.8±4.1 %, or ∼0.52 % yr−1), while the clean-ice area reduced from 643.2±25.9 to 511.0±20.9 km2 (20.1±4.0 %, or ∼0.73 % yr−1). In contrast supra-glacial debris cover increased from 7.0±6.4 %, or 48.3±3.1 km2, in 1986 to 13.4±6.2 % (∼0.22 % yr−1), or 79.0±4.9 km2, in 2014. Debris-free glaciers exhibited higher area and length reductions than debris-covered glaciers. The distribution of the supra-glacial debris cover differs between the northern and southern and between the western, central and eastern Greater Caucasus. The observed increase in supra-glacial debris cover is significantly stronger on the northern slopes. Overall, we have observed up-glacier average migration of supra-glacial debris cover from about 3015 to 3130 m a.s.l. (metres above sea level) during the investigated period.

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