Satellite GeodesyShahbaz Ali Khidri

OUTLINE• Geodesy and Space-Geodesy

• What is Geodesy ?

• Historical perspective

• Space-based technologies

• Applications

• Selected books on Geodesy

• References

GEODESY ?• One of the oldest profession of the world.

• It comes from the words:

Geo = Earth

Daisia = I divide

• Geo Daisia = Dividing the Earth

DEFINITION OF GEODESY• The classical definition:

Geodesy is the science of measuring, and portraying the earth’s surface.

[Helmert, 1880].

• The modern definition:

Geodesy is discipline that deals with the measurement and representation of the earth, including it’s gravity field, in a

3D time varying space.

(International Association of Geodesy)

Robert Helmert(1843 - 1917)

HISTORICAL PERSPECTIVE

• Eratostethens (276 BC – 194 BC) measured the angle of sun rays between Alexandria and Syene (Egypt).

• Measured the Earth’s circumference accurately with 15% deviation as compared to the current estimate.

SUB-DISCIPLINES OF GEODESY

• Geometrical Geodesy

• Dynamical Geodesy

• Mathematical Geodesy

• Space or Satellite Geodesy

• Marine Geodesy

• Etc.

SATELLITE GEODESY• Geodesy with the help of Satellites.

• It is used to study the climate change, water resources, natural hazards, disasters, etc.

SPACE GEODETIC TECHNOLOGIES

• Positioning techniques

• Global Navigation Satellite Systems (GNSS)

• Altimetry

• Gravity Missions

• Etc.

POSITIONING TECHNIQUES

• Satellite Laser Ranging

• Lunar Laser Ranging

• Etc.

POSITIONING TECHNIQUES

Satellite Laser Ranging Lunar Laser Ranging

GNSS• GPS

• GLONASS

• Galileo

• Compass

ALTIMETRY• SeaSAT

• GeoSAT

• TOPEX

• JASON-1

• ENVISAT

• Etc.

GRAVITY MISSIONS• GRACE

• CHAMP

• LAGEOS-1

• Etc.

GRACE

Measurements of small changes in the Earth’s gravitational fieldLAGEOS-1

APPLICATIONS• The Deformation of the Earth from Earthquakes.

APPLICATIONS• Volcano Monitoring.

Studies of hazardous volcanoes in Mexico, Central America and the Caribbean

APPLICATIONS• Monitoring of water resources.

Monitoring of water resources(Everglades, south Florida)

APPLICATIONS• Monitoring of soil moisture.

• Soil moisture is critical for vegetation growth and survival.

APPLICATIONS• Glacier flow.

APPLICATIONS• Landslides.

Ground movements in Berkley Hill, near San Francisco

APPLICATIONS

SELECTED BOOKS ON GEODESY

GEODESY: THE CONCEPTS

by Peter Vanicek, E.J. Krakiwsky,

Elsevier Science, 1996 Edition

GEODESYby Wolfgang Torge, Alter de

Gruyter, Berlin, 2000

INTRODUCTION TO GEODESY:The History and Concepts of Modern Geodesyby James R. Smith - 1997

SATELLITE GEODESY, FOUNDATIONS,METHODS, AND APPLICATIONS,by Gunter Seeber, Walter de Gruyter, Berlin, 2003

REFERENCES http://oceanservice.noaa.gov/education/kits/geodesy/welcome.html

http://gge.unb.ca/Research/GRL/GeodesyGroup/tutorial/tutorial.htm

http://www.geod.nrcan.gc.ca/geodesy/index_e.php

http://en.wikipedia.org/wiki/Geodesy

http://www.ngs.noaa.gov/PUBS_LIB/Geodesy4Layman/TR80003A.HTM

http://www.colorado.edu/geography/gcraft/notes/datum/datum.html

http://www3.sympatico.ca/craymer/geodesy/geodesy.html