Satellite Geodesy Notes

Subject of Satellite Geodesy

  • Definition:

    • Based on Helmert (1880/1884), geodesy is the science of measuring and mapping Earth's surface.

    • Involves determining the terrestrial gravity field and ocean floor.

  • Objectives of Satellite Geodesy:

    1. Precise determination of global, regional, and local 3D positions.

    2. Gravity field determination and creating a precise geoid.

    3. Measurement and modeling of geodynamical phenomena like polar motion and crustal deformation.

Basic Principles of Satellite Geodesy

  • Observational Techniques:

    • Analysis and observation of satellites and their interactions with Earth.

  • Requirements:

    • Comprehensive knowledge of satellite motion under forces.

    • Accurate position descriptions for satellites and ground stations.

  • Classification:

    • Integrates aspects of basic sciences and applied sciences.

Historical Development

  • Key Milestones:

    • Launch of SPUTNIK-1 on October 4, 1957, marking the start of modern satellite geodesy.

    • Evolution leading to the development of precise Earth models and observations of gravitational fields.

  • Significant Contributors:

    • Early works by Laplace, Hansen, Helmert, and Hill.

    • Innovations in the use of lunar methods as geometric targets before 1957.

Classification of Satellite Geodesy Techniques

  • Observation Methods:

    1. Earth to Space:

    • Techniques like satellite laser ranging and GPS.

    1. Space to Earth:

    • Radar altimetry and satellite gradiometry.

    1. Space to Space:

    • Including satellite-to-satellite tracking.

  • Prioritization of Techniques:

    • Earth-bound methods have reached advanced levels; others are still developing.

Applications of Satellite Geodesy

  • Global Geodesy:

    • Understanding Earth's shape and gravity field, establishing coordinate frames, linking geodetic datums.

  • Geodetic Control:

    • Designing and improving geometrical networks, including island-mainland connections.

  • Geodynamics:

    • Monitoring motion, Earth rotation, polar motion, solid Earth tides.

  • Navigation and Marine Applications:

    • Supporting precision navigation and mapping.

Future Directions

  • Ongoing Developments:

    • Improvements in the accuracy and resolution of geodetic techniques.

    • Focus on integrating new satellite systems (e.g., GNSS).

  • Expected Advances:

    • Launch of dedicated gravity field satellites, enhancing environmental monitoring and disaster prevention efforts.

Structure of the Book

  • Overview:

    • Focus on observation methods and applications in satellite geodesy.

    • Includes fundamentals of astronomy, signal propagation, and orbit determination methods.

  • Chapter Breakdown:

    • Chapters discuss satellite motion, observational techniques, and applications reflecting modern developments in satellite geodesy.