雨自文大電园地 Principles of the Global Positioning System Lecture 02 YUAN Linguo Email:lgyuan@163.com Dept of Surveying Engineering, Southwest Jiaotong University Overview GPS Basic Positioning Principle Two reference systems: Time and Coordinate Syst 9 GPS S=vt Time known 3 Coordinate System EX Principles of the Global Positioning System 2005-34(2
1 Principles of the Global Positioning System Lecture 02 YUAN Linguo Email: lgyuan@163.com Dept. of Surveying Engineering, Southwest Jiaotong University Principles of the Global Positioning System 2005-3-4 2
A Group of Basic Concepts 1. Sun and earth Spring 2. Earth ummer 3. Celestial body 21 12月21日 4. Ecliptic Plane Winter 5. Earth Equator Autumn 6. Celestial 7. Greenwich Meridian Principles of the Global Positioning System 2005-34(3 9. Nod 10. Pe ILA ② ■RBy像 目Mss扫描条带 NEV Principles of the Global Positioning System 2005-34(4
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12. Space-fixed Coordinate System 13. Earth-fixed Coordinate System 14. Artificial Earth Satellite 15. Orbital Plane 16. Orbital plane Coordinate System satellite perge node orbit UV Principles of the Global Positioning System Prime Meridian Equat O Degree Latitude EX Principles of the Global Positioning System 2005-34(6
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1. A uniform coordinate system 2. A three-dimensional Cartesian system The Xi -axis for the space-fixed system points towards the vernal X3=X X,-axis of the earth-fixed system defined by intersection line of the equatorial plane geocenter with the plane ted by the Greenwich vernal equinox meridian wv Principles of the Global Positioning System The angle Oo between the two systems is called Greenwich sidereal time The X-axis being orthogonal to both the x-axis and the x-axis completes a right-handed coordinate frame EX Principles of the Global Positioning System 2005-34(8
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Coordinate Systems o Definition of coordinates o Conventional"realization"of coordinates a Modern realizations using spaced based geodetic systems(such as GPS) wy Principles of the Global Positioning System 200534(9 Coordinate system definition To define a coordinate system you need to define: Its origin (3 a Its orientation(3 components, usually the direction cosines of one axis and one component of another axes, and definition of handed-ness) Its scale(units NEV Principles of the Global Positioning System
5 Principles of the Global Positioning System 2005-3-4 9 Coordinate Systems Definition of coordinates Conventional “realization” of coordinates Modern realizations using spaced based geodetic systems (such as GPS). Principles of the Global Positioning System 2005-3-4 10 Coordinate system definition To define a coordinate system you need to define: Its origin (3 component) Its orientation (3 components, usually the direction cosines of one axis and one component of another axes, and definition of handed-ness) Its scale (units)