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3 Dimensional Radar(TRMM PR)
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Ground Penetrating Radar : Basic and Applications for Civil Engineering
The document discusses ground penetrating radar (GPR), which uses radar pulses to image the subsurface. It explains that GPR can detect objects, material changes, and voids underground. The document then covers GPR principles, data acquisition, analysis, and applications in civil engineering projects like assessing bridge decks, detecting subsidence, and locating cultural artifacts. Examples of current GPR research, equipment, and software are also presented.
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Ground Penetrating Radar : Basic and Applications for Civil Engineering
- 1. Ground Penetrating Radar Basicfor Civil Engineering 2014. 04. 17 GPR Basic for Master’s Course Jiyoung Rhee Engineer Researcher
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- 6. RADAR Surveillance(Search) Radar (Army/Aiport) http://www.naval-technology.com 6/45
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- 8. RADAR 3 Dimensional Radar(TRMMPR) [Hurricane Sandy, Oct. 28, 2012 at 1725 UTC (1:25 PM EDT)]http://trmm.gsfc.nasa.gov/ 8/45
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- 10. RADAR • Radio DetectingAnd Ranging • An object-detection system that uses radio waves to determine the range, altitude, direction, or speed of objects. http://en.wikipedia.org/ 10/45
- 11. RADAR http://en.wikipedia.org/ Principle of aSonar or Radar Distance Measurement 11/45
- 12. G P R? 12/45
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- 14. Ground Penetrating Radar •A geophysical method that uses radar pulses to image the subsurface. • This nondestructive method detects the reflected signals from subsurface structures. http://en.wikipedia.org/ 14/45
- 15. Ground Penetrating Radar •GPR can be used in a variety of media, including rock, soil, ice, fresh water, pavements and structures. • It can detect objects, changes in material, and voids and cracks. http://en.wikipedia.org/ 15/45
- 16. Ground Penetrating Radar Deterioration Approach Thickness Pavement Sinkhole Rebar Tunnel 16/45
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- 18. Dielectric Constant • DielectricPermittivity is the property that describes the ability of a material to store electric energy by separating opposite polarity charges in space. (units : farads/metre(F/m)) • Relative dielectric permittivity (dielectric constant) is the ratio of the permittivity of a material to that of free space, 8.854×10−12 F/m. (No unit!) ASTM D 6432 – 11 3.2.9 18/45
- 19. Electrical Conductivity • Theability of a material to support an electrical current (material property that describes the movement of electrons or ions) due to an applied electrical field. (units : Siemens/metre (S/m)). ASTM D 6432 – 11 3.2.5 19/45
- 20. Electrical Properties Approximate ElectromagneticProperties of Various Materials ASTM D 6432 – 11 Table 1 20/45
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- 22. Data Acquisition ASTM D6432 – 11 Fig 1. Schematic Diagram of a Ground-Penetrating Radar System 22/45
- 23. Data Acquisition • GPRuses high-frequency radio waves and transmits into the ground. • When the wave hits a buried object or a boundary with different dielectric constants, the receiving antenna records variations in the reflected return signal. http://en.wikipedia.org/ 23/45
- 24. Data Acquisition • Thedepth range of GPR is limited by the electrical conductivity of the ground, the transmitted center frequency and the radiated power. • As conductivity increases, the penetration depth decreases. • Higher frequencies do not penetrate as far as lower frequencies, but give better resolution. http://en.wikipedia.org/ 24/45
- 25. Data Acquisition ASTM D6432 – 11 Fig 1. Schematic Diagram of a Ground-Penetrating Radar System Soil Buried Object Bed Rock Transmitter Antenna Receiver Antenna Control Unit Data Display Data Storage Ground Surface 25/45
- 26. Data Acquisition ASTM D6432 – 11 Fig 1. Schematic Diagram of a Ground-Penetrating Radar System Soil Buried Object Bed Rock Transmitter Antenna Receiver Antenna Control Unit Data Display Data Storage Ground Surface t1 26/45
- 27. Data Acquisition ASTM D6432 – 11 Fig 1. Schematic Diagram of a Ground-Penetrating Radar System Soil Buried Object Bed Rock Transmitter Antenna Receiver Antenna Control Unit Data Display Data Storage Ground Surface Different EM Properties t1 t2 27/45
- 28. Data Acquisition ASTM D6432 – 11 Fig 1. Schematic Diagram of a Ground-Penetrating Radar System Soil Buried Object Bed Rock Transmitter Antenna Receiver Antenna Control Unit Data Display Data Storage Ground Surface Different EM Properties t1 t2 28/45
- 29. Received Data ASTM D6432 – 11 Fig 1. Soil Buried Object Bed Rock Transmitter Antenna Receiver Antenna Control Unit Data Display Data Storage Ground Surface t1 t2 A1 A2 A Trace +- Time A1 A2 Volts t=t1+t2 29/45
- 30. Data Analysis • Depth ASTMD 6432 – 11 Eq. (1) m V t d 2 r m c V - c = propagation velocity in free space(3X108m/s) - Vm = propagation velocity through the material - εr = relative permittivity A Trace +- Time A1 A2 Volts t=t1+t2 30/45
- 31. GPR Survey &Analysis A Series of Traces Depth 1 2 3 4 5 Survey Time 1 2 3 4 5 Survey 31/45 Point Reflector
- 32. GPR Survey &Analysis A Series of Traces Depth 1 2 3 4 5 Survey Time 1 2 3 4 5 Survey 32/45 Line Reflector
- 33. GPR Survey &Analysis Wiggle Trace Linescans 33/45
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- 35. Rebars in aConcrete Pavement Linescans Wiggle Trace Surface Rebars 35/45
- 36. Layer Thickness atBridge Deck A/C Rebars Bottom 36/45
- 37. Subsidence near theDongtan IC Patching Subsidence B=1.2m Grouting Patching Grouting 37/45
- 38. Cultural Treasure inGyeongju http://news.dongascience.com/PHP/NewsView.php?kisaid=20120810200002327242 Gyeongju Wolseon, Gyeongsangbuk-do Seokbinggo 38/45
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- 41. Now & theFuture? 41/45
- 42. Now : Research 2012GPR Conference 42/45
- 43. Now : Equipment 2012GPR Conference 43/45
- 44. Now : Software 2012GPR Conference 44/45
- 45. The Future http://cait.rutgers.edu The Robotfor Bridge Deck Assessment 45/45
- 46. Question? Jiyoung Rhee Mobile :031-371-2761 Mailto : need@ex.co.kr http://www.slideshare.net/ssuser6b53da