Issue 10 Volume 41 May 16, 2003

This 2001 Annual Report of the International Laser Ranging Services (ILRS) is comprised of individual contributions
from ILRS components within the international geodetic community. This report documents the work of the ILRS components
for the year 2001. The report documents changes and progress of the ILRS. This document is also available on the ILRS Web
site at http://ilrs.gsfc.nasa.gov/reports/ilrs_reports/ilrsar_2001.html.
Author
Laser Ranging; Geophysics; Geodynamics; Geodesy; Research Facilities; Project Management; Data Management
20030032516 Instituto Nacional de Pesquisas Espacias, Sao Jose dos Campos, Brazil
Global Projection of Rangel: A Projection System of Terrestrial Globe on an Ellipsoid
Rangle, Ricardo Rodriques; 2003; 212 pp.; In Portuguese; Original contains black and white illustrations
Report No.(s): INPE-9559-TDI/834; Copyright; Avail: CASI; A10, Hardcopy
This work proposes a new mathematical methodology to represent the terrestrial global on an ellipsoid, capable of offering
equations for dealing geodetic positions, geo-reference, and distance and bearings determination, with variable precision and
continuity of information in whole ellipsoid. The study has been developed with the intention of creating a projection
mechanism, in three dimensions, able to reduce or eliminate all found limitations in actual cartographic projection systems,
as Universal Transverse of Mercator and Conical of Lambert. All mathematical equations have been implemented and tested
in computational environment.
Author
Numerical Analysis; Mercator Projection; Terrestrial Planets; Geodetic Coordinates; Distance
20030032518 NASA Goddard Space Flight Center, Greenbelt, MD, USA
Atmospheric Pressure Corrections In Geodesy and Oceanography: A Strategy For Handling Air Tides
Ponte, Rui M.; Ray, Richard D., Americ; Geophysical Research Letters; January 2003; ISSN 0094-8276, pp. 1-3; In English;
Original contains black and white illustrations
Contract(s)/Grant(s): Proj-1206432; Copyright; Avail: Other Sources
Global pressure data are often needed for processing or interpreting modern geodetic and oceanographic measurements.
The most common source of these data is the analysis or reanalysis products of various meteorological centers. Tidal signals
in these products can be problematic for several reasons, including potentially aliased sampling of the semidiurnal solar tide
as well as the presence of various modeling or timing errors. Building on the work of Van den Dool and colleagues, we lay
out a strategy for handling atmospheric tides in (re)analysis data. The procedure also offers a method to account for ocean
loading corrections in satellite altimeter data that are consistent with standard ocean-tide corrections. The proposed strategy
has immediate application to the on-going Jason-1 and GRACE satellite missions.
Author
Atmospheric Pressure; Error Analysis; Correlation; Geodesy; Oceanography; Atmospheric Tides
20030032932 Pennsylvania State Univ., State College, PA
Monte Carlo Simulation of Seismic Location Errors for Moving Vehicles
Greenfield, Roy J.; Moran, M. L.; Oct 2001; 17 pp.; In English; Original contains color illustrations
Report No.(s): AD-A410216; No Copyright; Avail: CASI; A03, Hardcopy
A method was developed to predict the distribution of seismic source mislocation errors for tracked vehicles using bearing
and range (r) location statistics obtained from field data. The method is of use for 1) guiding the design and deployment of
seismic sensor networks and 2) statistically modeling seismic network tracking performance. In the present work, a seismic
array is composed of one or multiple seismic subarrays each of which makes estimates of bearing and range. The bearing and
range estimates are taken to be normally distributed around the true target location with errors sigma(sup b) and sigma(sup
r) respectively. When these sigma’s are used in our Monte Carlo simulation, we chose a true source point, and network
geometry (array locations). Using these source and sensor positions, a set of true bearing and rare computed. The Monte Carlo
simulation is done with 100 trials, in each trial a random error is added to the true bearing and r for each array according to
the observed sigma. For each of the 100 bearing and r Monte Carlo measurements, a weighted least squares solution for the
East and North value of the source is found. A statistical fit for all 100 trials is used to find the 9007) confidence location ellipse
surrounding the true source point. Two types of displays are presented. The first fixes sigma(sup b)and sigma(sup r) and makes
a map that displays the error ellipse axes and orientation as a function of map position. The second uses a fixed map position
and displays the error ellipse axes and orientation as a function of sigma(sup b) and sigma(sup r). This allows convenient
analysis of how the location error changes with changes of the array measurement accuracy. The later format is particularly
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