scholarly journals GPS measurement at summit peaks of the Taisetsu mountains, Central Hokkaido, Japan

2000 ◽  
Vol 52 (11) ◽  
pp. 1019-1021 ◽  
Author(s):  
Takayuki Kaneso ◽  
Junji Koyama ◽  
Takeo Moriya ◽  
Hiroaki Takahashi
Keyword(s):  
Gps Measurement

scholarly journals Identifying resting locations of a small elusive forest carnivore using a two-stage model accounting for GPS measurement error and hidden behavioral states

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Dalton J. Hance ◽  
Katie M. Moriarty ◽  
Bruce A. Hollen ◽  
Russell W. Perry
Keyword(s):  
Time Series ◽  
Measurement Error ◽  
Gaussian State ◽  
Parameter Estimates ◽  
Accelerometer Data ◽  
Two Stage ◽  
Location Data ◽  
Gps Measurement ◽  
Activity Measurements ◽  
Behavioral States

Abstract Background Studies of animal movement using location data are often faced with two challenges. First, time series of animal locations are likely to arise from multiple behavioral states (e.g., directed movement, resting) that cannot be observed directly. Second, location data can be affected by measurement error, including failed location fixes. Simultaneously addressing both problems in a single statistical model is analytically and computationally challenging. To both separate behavioral states and account for measurement error, we used a two-stage modeling approach to identify resting locations of fishers (Pekania pennanti) based on GPS and accelerometer data. Methods We developed a two-stage modelling approach to estimate when and where GPS-collared fishers were resting for 21 separate collar deployments on 9 individuals in southern Oregon. For each deployment, we first fit independent hidden Markov models (HMMs) to the time series of accelerometer-derived activity measurements and apparent step lengths to identify periods of movement and resting. Treating the state assignments as given, we next fit a set of linear Gaussian state space models (SSMs) to estimate the location of each resting event. Results Parameter estimates were similar across collar deployments. The HMMs successfully identified periods of resting and movement with posterior state assignment probabilities greater than 0.95 for 97% of all observations. On average, fishers were in the resting state 63% of the time. Rest events averaged 5 h (4.3 SD) and occurred most often at night. The SSMs allowed us to estimate the 95% credible ellipses with a median area of 0.12 ha for 3772 unique rest events. We identified 1176 geographically distinct rest locations; 13% of locations were used on > 1 occasion and 5% were used by > 1 fisher. Females and males traveled an average of 6.7 (3.5 SD) and 7.7 (6.8 SD) km/day, respectively. Conclusions We demonstrated that if auxiliary data are available (e.g., accelerometer data), a two-stage approach can successfully resolve both problems of latent behavioral states and GPS measurement error. Our relatively simple two-stage method is repeatable, computationally efficient, and yields directly interpretable estimates of resting site locations that can be used to guide conservation decisions.

scholarly journals Correction to: Identifying resting locations of a small elusive forest carnivore using a two-stage model accounting for GPS measurement error and hidden behavioral states

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Dalton J. Hance ◽  
Katie M. Moriarty ◽  
Bruce A. Hollen ◽  
Russell W. Perry
Keyword(s):  
Measurement Error ◽  
Stage Model ◽  
Two Stage ◽  
Gps Measurement ◽  
Behavioral States

An amendment to this paper has been published and can be accessed via the original article.

scholarly journals Geospatial Technology for Landslide Susceptibility Mapping along the Vathalmalai Ghat road section, South India

2021 ◽  
Vol 30 (4) ◽  
pp. 683-691
Author(s):  
G. Kavitha ◽  
S. Anbazhagan ◽  
S. Mani
Keyword(s):  
Landslide Susceptibility ◽  
Drainage Density ◽  
Landslide Susceptibility Mapping ◽  
Slope Aspect ◽  
Susceptibility Map ◽  
Landslide Susceptibility Zonation ◽  
Road Section ◽  
Gps Measurement ◽  
Causative Factors ◽  
Very High

Landslides are among the most prevalent and harmful hazards. Assessment of landslide susceptibility zonation is an important task in reducing the losses of lifeand properties. The present study aims to demarcate the landslide prone areas along the Vathalmalai Ghat road section (VGR) using remote sensing and GIS techniques. In the first step, the landslide causative factors such as geology, geomorphology, slope, slope aspect, land use / land cover, drainage density, lineament density, road buffer and relative relief were assessed. All the factors were assigned to rank and weight based on the slope stability of the landslide susceptibility zones. Then the thematic maps were integrated using ArcGIS tool and landslide susceptibility zonation was obtained and classified into five categories ; very low, low, moderate, high and very high. The landslide susceptibility map is validated with R-index and landslide inventory data collected from the field using GPS measurement. The distribution of susceptibility zones is ; 16.5% located in very low, 28.70% in low, 24.70% in moderate, 19.90% in high and 10.20% in very high zones. The R-index indicated that about 64% landslide occurences correlated with high to very high landslide susceptiblity zones. The model validation indicated that the method adopted in this study is suitable for landslide disaster mapping and planning.

scholarly journals MONITORING OF LAND SUBSIDENCE IN RAVENNA MUNICIPALITY USING INTEGRATED SAR - GPS TECHNIQUES: DESCRIPTION AND FIRST RESULTS

2016 ◽  
Vol XLI-B7 ◽  
pp. 23-28 ◽  
Author(s):  
G. Artese ◽  
S. Fiaschi ◽  
D. Di Martire ◽  
S. Tessitore ◽  
M. Fabris ◽  
...  
Keyword(s):  
Land Subsidence ◽  
Interferometric Synthetic Aperture Radar ◽  
Persistent Scatterers ◽  
Gps Measurement ◽  
Measurement Results ◽  
Prone Area ◽  
First Results ◽  
Emilia Romagna Region ◽  
Small Baseline Subset ◽  
Small Baseline

The Emilia Romagna Region (N-E Italy) and in particular the Adriatic Sea coastline of Ravenna, is affected by a noticeable subsidence that started in the 1950s, when the exploitation of on and off-shore methane reservoirs began, along with the pumping of groundwater for industrial uses. In such area the current subsidence rate, even if lower than in the past, reaches the -2 cm/y. Over the years, local Authorities have monitored this phenomenon with different techniques: spirit levelling, GPS surveys and, more recently, Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques, confirming the critical situation of land subsidence risk. In this work, we present the comparison between the results obtained with DInSAR and GPS techniques applied to the study of the land subsidence in the Ravenna territory. With regard to the DInSAR, the Small Baseline Subset (SBAS) and the Coherent Pixel Technique (CPT) techniques have been used. Different SAR datasets have been exploited: ERS-1/2, ENVISAT, TerraSAR-X and Sentinel-1. Some GPS campaigns have been also carried out in a subsidence prone area. 3D vertices have been selected very close to existing persistent scatterers in order to link the GPS measurement results to the SAR ones. GPS data were processed into the International reference system and the comparisons between the coordinates, for the first 6 months of the monitoring, provided results with the same trend of the DInSAR data, even if inside the precision of the method.

The spectrum of GPS measurement errors and the accuracy of airborne gravity measurements

Geophysics ◽  
1990 ◽  
Vol 55 (8) ◽  
pp. 1101-1104 ◽  
Author(s):  
D. R. Bower ◽  
J. Kouba ◽  
R. J. Beach
Keyword(s):  
Measurement Errors ◽  
Regional Scale ◽  
Vertical Motion ◽  
Airborne Gravity ◽  
Width Ratio ◽  
Noise Power ◽  
Power Spectral ◽  
Gps Measurement ◽  
Gravity Measurements ◽  
Allowable Error

Recent observations (Georgiadou and Kleusberg, 1987; Kleusberg et al., 1989) suggest that errors in GPS carrier phase observations at frequencies within the gravity passband of airborne gravity systems may be due mainly to multipath interference. Further, the power spectral density (PSD) of these errors has been found to fall off rapidly with increase in frequency throughout the anticipated gravity passband, in the manner of a red spectrum rather than a white (which remains constant). It is shown that this implies a much greater allowable error in GPS‐derived altitude reference than would be the case if the PSD of altitude errors (1) was white, (2) had the same shape as that of typical aircraft vertical motion, or (3) was dominated by a sinusoidal wave located near the high frequency limit of the gravity passband. This enhances the feasibility of airborne gravity for regional scale surveys and perhaps explains why actual measurements have been better than predicted. For example, given a uniform [Formula: see text] distribution of spectral noise power and a speed to grid‐width ratio of 60 per hour, an rms altitude error as large as 12 cm will still allow the computation of acceleration correction with an accuracy of 2 mGal. For the same conditions, the allowable rms altitude error given a white distribution of spectral noise power is 1.5 cm.

Accurate GPS measurement of the location and orientation of a floating platform

1990 ◽  
Vol 14 (3-4) ◽  
pp. 255-264 ◽  
Author(s):  
G. H. Purcell ◽  
L. E. Young ◽  
S. Kornreich Wolf ◽  
T. K. Meehan ◽  
C. B. Duncan ◽  
...  
Keyword(s):  
Floating Platform ◽  
Gps Measurement
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