Abstract:A second‐order Markov process is proposed as a statistical model for gravity anomalies in a local region. The method is applied to the analysis of errors in an inertial navigation system caused by unknown gravity phenomena. Statistical models of vertical deflection obtained from the anomaly model by means of the Vening Meinesz equations yield predictions of rms position and velocity errors for the navigation system. Actual vertical deflection data are used as simulated inputs to a computer model of an inertial… Show more
“…The distribution of the ice sheet data and the majority of was used to generate the DEM from the data [Kasper, 1971]. This approach has been shown to be effective for elevation modeling as it takes into account variations in data accuracy in the determination of the weighting matrix so that the detail in the DEM reflects the local data quality [Ekholm, 1996].…”
Abstract.A new digital elevation model of the Greenland ice sheet and surrounding rock outcrops has been produced at 1-km postings from a comprehensive suite of satellite remote sensing and cartographic data sets. Height data over the ice sheet were mainly from ERS-1 and Geosat radar altimetry. These data were corrected for a slope-dependent bias that had been identified in a previous study. The radar altimetry was supplemented with stereophotogrammetric data sets, synthetic aperture radar interferometry, and digitized cartographic maps over regions of bare rock and where gaps in the satellite altimeter coverage existed. The data were interpolated onto a regular grid with a spacing of-•l km. The accuracy of the resultant digital elevation model over the ice sheet was assessed using independent and spatially extensive measurements from an airborne laser altimeter that had an accuracy of between 10 and 12 cm.
“…The distribution of the ice sheet data and the majority of was used to generate the DEM from the data [Kasper, 1971]. This approach has been shown to be effective for elevation modeling as it takes into account variations in data accuracy in the determination of the weighting matrix so that the detail in the DEM reflects the local data quality [Ekholm, 1996].…”
Abstract.A new digital elevation model of the Greenland ice sheet and surrounding rock outcrops has been produced at 1-km postings from a comprehensive suite of satellite remote sensing and cartographic data sets. Height data over the ice sheet were mainly from ERS-1 and Geosat radar altimetry. These data were corrected for a slope-dependent bias that had been identified in a previous study. The radar altimetry was supplemented with stereophotogrammetric data sets, synthetic aperture radar interferometry, and digitized cartographic maps over regions of bare rock and where gaps in the satellite altimeter coverage existed. The data were interpolated onto a regular grid with a spacing of-•l km. The accuracy of the resultant digital elevation model over the ice sheet was assessed using independent and spatially extensive measurements from an airborne laser altimeter that had an accuracy of between 10 and 12 cm.
“…Position reference errors are modeled as biases by t,he equations 2 Other more complicated models are often used also [10]- [12].…”
Section: Evaluatim By Covariance Simulationmentioning
confidence: 99%
“…6, , 6, Kort,h, east vertica.1 deflection component,s.The 3. angles are small misalignment angles bet,ween the platform and computer and they obey t.he differential equations $ n = -Q sin L+e + en(12) $, = D sin L#n + Q cos L#2 + e,…”
“…For local models, the earth is assumed to be flat. The popular models used to represent either gravity or anomalous potential autocovariance function are self‐consistent planar covariance models, namely the familiar class of Markov models (Shaw et al 1969; Kasper 1971; Jordan 1972), Poisson and reciprocal distance covariance models (Nash & Jordan 1978), the planar logarithm covariance model (Forsberg 1987). However, except the planar logarithm covariance model, these models fail to produce the correct asymptotic decay of the power spectral density at high spatial frequencies.…”
S U M M A R YAn anisotropic covariance model embedded with self-affine characteristics of gravity and bathymetry anomalies is proposed. High-resolution free air gravity data obtained from the high-density satellite altimetry data have been used to study the self-affinity of the gravity measurements. The digital terrain model-5 (DTM-5) is used for the bathymetry data. The Hurst coefficients (H) are calculated using 2-D power spectral density of the free air gravity and bathymetry data from 140 blocks of 1 • × 1 • . The Hurst coefficients (H) are also determined for free air gravity data along 24 orthogonal profiles using rescaled range (R/S) analysis. Further, the estimated H values are used in order to find the appropriate gravity and bathymetry covariance model for the area. The average value of H is more for 2-D free air gravity data as compared with the bathymetry data. The H values from the 1-D free air gravity profiles are found to be 0.75 and 0.77 along the N-S and E-W directions, respectively. The Von Karman covariance model with different correlation lengths is found to be suitable for 2-D and 1-D free air gravity and 2-D bathymetry data.
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