LIDAR

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LIDAR

• GAJENDRA KUMAR
• EC 3rd YR.
• ROLL NO.- 0800131040

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CONTENTS
MADE BY MANISH KR.

• Introduction
• LIDAR- What???
• Why???
• How(operating principle)???
  
• Traditional photography VS Lidar
• Components and
• Characteristics

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LIDAR

• Light Detection And Ranging
• is an optical remote sensing technology that can
  measure the distance to, or other properties of a
  target by illuminating the target with light,
  often using pulses from a laser.

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General Description

• LIDAR uses ultraviolet, visible, or near infrared
  light to image objects and can be used with a
  wide range of targets, including non-metallic
  objects, rocks, rain, chemical compounds,
  aerosols, clouds and even single molecules.1 A
  narrow laser beam can be used to map physical
  features with very high resolution.

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HOW????

• Each time the laser is pulsed
• Laser generates an optical pulse
• Pulse is reflected off an object and returns
• to the system receiver
• High-speed counter measures the time of flight
  from the start pulse to the return pulse
• Time measurement is converted to a distance (the
  distance to the target and the
• position of the airplane is then used to
  determine
• the elevation and location)
• Multiple returns can be measured for each pulse

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COMPONENTS

1. LASER
2. SCANNER AND OPTICS
3. PHOTODETECTOR AND RECEIVER
4. POSITION AND NAVIGATIONAL SYS.

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LASER

• -6001000 nm lasers are most common for non
  scientific applications
• -Airborne topographic mapping lidars generally
  use 1064 nm diode pumped YAG lasers
• -Better target resolution is achieved with
  shorter pulses, provided the LIDAR receiver
  detectors and electronics have sufficient
  bandwidth1.

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SCANNER AND OPTICS

• How fast images can be developed is also affected
  by the speed at which it can be scanned into the
  system .
• There are several options to scan the azimuth and
  elevation, including dual oscillating plane
  mirrors, a combination with a polygon mirror, a
  dual axis scanner

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PHOTODETECER

• Two main photodetector technologies are used in
  lidars solid state photodetectors, such as
  silicon avalanche photodiodes, or
  photomultipliers
• The sensitivity of the receiver is another
  parameter that has to be balanced in a LIDAR
  design.

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NAVIGATIONAL SYS.

• LIDAR sensors that are mounted on mobile
  platforms such as airplanes or satellites require
  instrumentation to determine the absolute
  position and orientation of the sensor.
• Such devices generally include a Global
  Positioning System receiver and an Inertial
  Measurement Unit (IMU).

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BASIC PRINCIPLE

• Similar principle to RADAR pulses of light
  emitted into the atmosphere and scattered back by
  clouds, aerosols or air molecules
• Light collected by a telescope
• Spectrometers or interference filters isolate
  wavelength concerned
• Photon-counting or analogue detection
• Time-of-flight gives scattering height z2ct

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TRADITIONAL PHOTOGRAPHYVSLIDAR

• 1.Day time collection only
• 2. Complicated and sometimes unreliable
  procedures
• 3. Planimetric accuracy is better than vertical

• 1.Day or night data acquisition
• 2.Direct acquisition of 3D collection
• 3. Vertical accuracy is better than planimetric

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APPLICATIONS

• AGRICULTURE
• ARCHAEOLOGY
• BIOLOGY CONSERVATION
• GEOLOGY
• HYDROLOGY
• METROLOGY

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