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Hydrographic Surveying - Geodetic Control And Tidal Effects
- 1. HYDROGRAPHIC SURVEYING LECTURE 5: GEODETIC CONTROLAND TIDAL EFFECTS BY: AHMED YASSER AHMED MOHAMED NASSAR SECTION: 1 ID:20
- 2. Horizontal Positioning Conventional visual andoptical Stadia /azimuth Sextant resection Triangulatio n Tagline procedures Shore- based theodolite intersection Baseline range alignment Electronic Electronic Distance Differential Datellite Positioning (DGPS)
- 3. POSITIONING BY 3 POINTSEXTANT • Position of Vessel is determined by • measuring 2 angles (AOC , COE) between 3 known points (A, C, E) ayassern@hotmail.com 3
- 4. BASELINE RANGE ALIGNMENT 1. Settingbaseline along the shore. 2. Setting stakes at equal distances to make even stations along the baseline. 3. Form and offshore grid by making perpendicular offsets to the even stations . 4. Position obtained by intersection of baseline range alignment ayassern@hotmail.com 4 inexpensive economical reliable
- 5. 2 – ELECTRONIC POSITIONING ayassern@hotmail.com5 Electronic Distance Measurements Short range Medium range Long range Positioning Range-Range Intersection method Resection method Range-Azimuth
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- 8. Differential GPS (DGPS) DGPS (DifferentialGPS) is essentially a system to provide positional corrections to GPS signals. DGPS uses a fixed, known position to adjust real time GPS signals to eliminate pseudorange errors. ayassern@hotmail.com 8
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Editor's Notes
- #2 Measuring the depth of water aboard a frigate, illustration of 1844 صورة توضح قياس الأعماق , 1844