•ICAO STANDARD – WGS84 (World Geodetic System 1984) POLAR RADIUS: 3432nm •2 Different Radius EQUATORIAL RADIUS: 3443nm •COMPRESSION RATIO : 1/297 (a-b/a)Feb-12 Alejandro Menéndez , MA. 2011 3
•EAST: Direction in which the Earth rotates. Anticlockwise to a person looking down on the N.Pole •WEST: Opposite to EastFeb-12 Alejandro Menéndez , MA. 2011 4
DEFINITION: Circle drawn on the surface of the Earth that divides the world into 2 equal hemispheres. Its center is the same that the one from the Earth it self. (Great Circle & Rhumb line) Sets a reference for North and South latitudesFeb-12 Alejandro Menéndez , MA. 2011 5
DEFINITION: Circles drawn on the surface of the Earth parallel to the Equator that extend up to the Poles. Named by the angle between the plane of the Equator and the line joining the center of the Earth and any point on parallel (Small circles) Extention: From 0º (Equator) to 090º N/S (North/South Poles)Feb-12 Alejandro Menéndez , MA. 2011 7
DEFINITION: Semi circles drawn on the surface of the earth that joint the 2 Poles and cross the Equator and all the parallels at right angles. PROPERTIES: • The special one: PRIME MERIDIAN (Sets reference for East and West) • Each meridian has an ANTI-MERIDIAN • Forms a complete GC with its anti-meridianFeb-12 Alejandro Menéndez , MA. 2011 9
DEFINITION: Circle drawn on the surface of a sphere with its center on the center of the sphere. E.g.: Equator and Meridians PROPERTIES • Connects any 2 points on Earths surface • Only 1 GC over 2 points (Exceptions) • Is the path RADIO SIGNALS follow ORTHOMORPHIC PATH • Short path: Shortest possibleFeb-12 Alejandro Menéndez , MA. 2011 12
VERTEX OF A GREAT CIRCLE: Most northerly and southerly points of a GC. PROPERTIES • Northern and southern are ANTIPODAL (Diametrically opposed) • 10,800 nm distant • At the vertex the direction of the GC is 090º – 270º • Are placed at 90º longitude from the point whereFeb-12 the GCMenéndez ,the2011 Alejandro cuts MA. Equator 13
DEFINITION: Circle drawn on the surface of a sphere that doesn’t have its center co-located with the one of the sphere. E.g.: Parallels of latitudeFeb-12 Alejandro Menéndez , MA. 2011 15
DEFINITION: Regularly curved line on the surface of the Earth that cuts all meridians at same angle. LOXODROMIC path. PROPERTIES • Only 1 RL through 2 points on Earths surface • Not GC (Exceptions: Meridians & Equator) • Mathematically will never reach the Pole (Spiral) • Distance with GC Greater over long distances. Increases with latitudeFeb-12 Alejandro Menéndez , MA. 2011 16
• Normally , flights of less than 1,000 nm are flown along a rhumb line. • Long trips can be divided into short legs of rhumb lines. • The easiest to follow because you only have to set a heading. Constant direction trackFeb-12 Alejandro Menéndez , MA. 2011 18
1. How can we know one vertex knowing the other? 2. How can we know the cutting angle between GC and Equator knowing one vertex position? 3. How can we know the vertex longitudes by knowing the long of the cutting point between Eq and GC? 4. How can we get one of the Earth’s radius knowing the other and the compression ratio?Feb-12 Alejandro Menéndez , MA. 2011 20
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