light-detection-and-ranging(lidar)

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light-detection-and-ranging(lidar)

  1. 1. LIDAR(Light Detection& Ranging) BY: p.sandeepkumar 092m1a04a1 BRANCH-ECE
  2. 2. INTRODUCTION What is LIDAR ? Remote sensing technology Uses much shorter wavelength of EM spectrum Measures properties of scattered light Measures time delay between transmitted and reflected signals Highly sensitive to aerosols and cloud particles
  3. 3. BASIC PRINCIPLE OF LIDAR In RADAR, radio waves are transmitted into the atmosphere, which scatters some of the power back to the Rader’s receiver. A LIDAR also transmits & receives electro-magnetic radiation and operate in the ultraviolet, visible and infrared region of the electromagnetic spectrum. The LIDAR is also popularly known as LASER RADAR. A LIDAR basically consists of a transmitter, receiver & detector
  4. 4. LIDAR vs. RADAR LIDAR uses much shorter wavelength of UV, visible and near IR range LIDAR is highly sensitive to non-metallic objects LIDAR has very narrow beam which produces high resolution This makes LIDAR a better choice for studying weather patterns using small technology, which is especially useful for studying distant atmospheres through satellites orbiting around other planets.
  5. 5. LIDAR TYPES  based on backscattering : Rayleigh LIDAR  Mie LIDAR  Raman LIDAR Other types: Coherent LIDAR(phase sensitive)  Incoherent LIDAR(amplitude measurement)
  6. 6. TECHNOLOGIES USED Integration Of three technologies to produce Digital Elevation Models(DEM) They are: Lasers  Global Positioning System(GPS)  Inertial Navigation System(INS)
  7. 7. WORKING Laser produces optical pulse Pulse is transmitted , reflected and returned to the receiver Receivers accurately measures the travel time X,Y,Z ground coordinates can be calculated using : Laser range  Laser scan angle  Laser Position from GPS  Laser orientation from INS
  8. 8. LIDAR TECHNOLOGY
  9. 9. COMPONENTS Laser:  600-1000nm lasers used for non-scientific application  Inexpensive  Easily absorbed by eye  1500nm lasers  less advanced, longer range , lower accuracy  Eye safe at much higher power level  Used in military application
  10. 10. Contd….. Scanner Used to scan the objects , azimuth and elevation  Uses : Dual oscillating plane mirror  Dual axis scanner Optics  They affect angular resolution and range  To Collect return signal it uses : Hole mirror  Beam splitter
  11. 11. Contd….. Photo detector and receiver electronic  Solid state photo detectors  Silicon avalanche photodiodes Position and navigation systems  Global Positioning System receiver  Inertial Measurement Unit(IMU)
  12. 12. APPLICATIONS LIDAR-equipped mobile robot  Used for constructing map
  13. 13. Contd…. Meteorology and Atmospheric Environment Used for studies of atmospherics conditions , structures , clouds and aerosols. Used for measurement of atm. gas Measures wind speed
  14. 14. Contd…. PHYSICS AND ASTRONOMY Measure the distance to reflectors placed on the moon Used in Mars-Orbiting Satellite to produce precise global topographic survey of Mars Used to detect snow in Mars atmosphere Used to measure molecular density
  15. 15. Contd…. MILITARY AND LAW ENFORCEMENT Used in traffic speed enforcement for vehicle speed measurement Uses the principle of time of flight to calculate speed Able to find the vehicle speed from cluster traffic situation Higher resolution system collect detail to identify targets (tanks)
  16. 16. CAPTURE OF ELEVATION POINTS Collects only elevation data GPS antenna is mounted on upper fuselage GPS sensors records the data Data are downloaded and processed X,Y,Z coordinates are found
  17. 17. OTHER APPLICATIONS FLOOD RISK MAPPING Quickest and most accurate method to measure DEM Easy flood prediction and plan mitigation and remediation strategies
  18. 18. Contd…. OIL & GAS EXPLORATION SURVEYS Provide high speed data acquisition and limit ground intervention Done using either a fixed wing or helicopter mounted LIDAR system
  19. 19. Contd…. ENGINEERING/CONSTRUCTION SURVEY Using DEM cut and fill quantities can be more precisely estimated Time delay between data acquisition and delivery is very less Air bourn LIDAR provide a cost effective and quick surveys for real estate development
  20. 20. Contd…. TRANSMISSION LINE MAPPING Calculating power line heights or sag under different loads  Inventory  Tower Placement  Height of underlying vegetation
  21. 21. ADVANTAGES&DISADVATAGES Large information bandwidth and extremely high angular resolution possibilities are some of the advantages of LIDARs  low efficiencies and atmospheric propagation limitations are some of the disadvantages
  22. 22. CONCLUSION It has allowed data to be collected that was difficult or impossible to obtain prior to its introduction. Data collection and its processing is relatively fast LIDAR saves clients money LIDAR offers flexibility LIDAR is unobtrusive and environmentally friendly
  23. 23. REFERENCES www.wikipedia.org www.lidar.com www.ambercore.com www.gisdevelopment.net www.lidarmap.org www.velodyne.com/lidar/
  24. 24. THANK YOU

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