Date post: | 13-Jul-2015 |
Category: |
Technology |
Upload: | vedant-srivastava |
View: | 637 times |
Download: | 3 times |
INTRODUCTION TO LIDAR TECHNOLOGY
Basics Of LIDAR Technology
• Acronym Light Detection And Ranging.
• It is a Remote Sensing technology that measure the distance by
illuminating the target with Laser and analysing the reflected light.
• Lidar uses ultraviolet, visible, or near infrared light to image objects.
• It can target a wide range of materials, including non-metallic objects,
rocks, rain, chemical compounds, aerosols, clouds and even
single molecules.
Basics Of LIDAR Technology
• A narrow laser-beam can map physical features with very
high resolution.
• Its wavelength vary to suit the target: from about 10 micro-meters to
the Ultra Violet Radiation of 250 nm.
• In LIDAR, Light is reflected via back-scattering.
• Different types of scattering are used for different lidar applications:
most commonly Rayleigh scattering, Mie scattering, Raman scattering,
and fluorescence.
Working Principle
Basic Formula For Range Measurement
Working Principle
Topographic LiDAR
BASIC COMPONENT
Global Positioning System (GPS)
Inertial Navigation System (INS)
LASER SYSTEM
And Unmanned Aerial Vehicle
Topographic Lidar is used to
make high resolution digital
map of land surfaces.
Multiple Return LiDAR
GENERAL LIDAR EQUATION
Lidar equation is the fundamental equation in laser remote sensing
field to relate the received photon counts (or light power) with the
transmitted laser photon counts (or laser power), light propagation in
background atmosphere, physical interaction between light and objects,
and lidar system efficiency and geometry, etc.
Application
• Agriculture : Create a Topographical map of
the fields and reveals the slopes and sun
exposure of the farm land.
• Archaeology:
• Autonomous vehicles: Autonomous vehicles
use lidar for obstacle detection and avoidance
to navigate safely through environments.
• Biology and conservation
• Geology and soil science: ICESat (Ice,
Cloud, and land Elevation Satellite)
• Atmospheric Remote Sensing and
Meteorology
• Law enforcement: Lidar speed guns
• Military
• Physics and astronomy, Robotics and
Spaceflight
• Surveying, Transport , wind farm
optimization and many more.
Present Technical Advancement in LIDAR
LIDAR speed gun
A LiDAR speed gun is a device used by the police for speed limit enforcement which
uses LiDAR to detect the speed of a vehicle. Unlike Radar speed guns, which rely
on Doppler shifts to measure the speed of a vehicle, these devices allow a police officer
to measure the speed of an individual vehicle within a stream of traffic.
Present Technical Advancement in LIDAR
LITE: Measuring the Atmosphere With Laser Precision
LITE (Lidar In-Space Technology Experiment) was space shuttle
mission from NASA which orbited the Earth while positioned inside the
payload bay of Space Shuttle Discovery. During this nine-day mission,
LITE measured the Earth's cloud cover and track various kind of
particles in the atmosphere. Designed and built at the NASA Langley
Research Center, LITE is the first use of a lidar (light detection and
ranging) system for atmospheric studies from space.
Present Technical Advancement in LIDAR
Google driverless car
Google's robotic cars have about $150,000 in
equipment including a $70,000 lidar (light
radar) system. The range finder mounted on the
top is a Velodyne 64-beam laser. This laser
allows the vehicle to generate a detailed 3D map
of its environment. The car then takes these
generated maps and combines them with high-
resolution maps of the world, producing
different types of data models that allow it to
drive itself.
Present Technical Advancement in LIDAR
Lunar Laser Ranging
experiment
The ongoing Lunar Laser Ranging
Experiment measures the distance between
the Earth and the Moon using laser
ranging. Lasers on Earth are aimed at retro
reflectors planted on the Moon during the Apollo
program (11, 14, and 15), and the time for the
reflected light to return is determined.
Present Technical Advancement in LIDAR
Autonomous cruise control
system
Autonomous cruise control (also called adaptive
or radar cruise control) is an optional cruise
control system for road vehicles that
automatically adjusts the vehicle speed to
maintain a safe distance from vehicles ahead. It
makes no use of satellite or roadside
infrastructures nor of any cooperative support
from other vehicles. Hence control is imposed
based on sensor information from on-
board sensors only.
Present Technical Advancement in LIDAR
ICESat (Ice, Cloud, and land Elevation
Satellite)
It is a part of NASA's Earth Observing System,
was a satellite mission for measuring ice sheet
mass balance, cloud and aerosol heights, as well
as land topography and vegetation
characteristics. ICESat was launched 13
January 2003 on a Delta II rocket
from Vandenberg Air Force Base in California
into a near-circular, near-polar orbit with an
altitude of approximately 600 km. It operated
for seven years before being retired in February
2010, after its scientific payload shut down and
scientists were unable to restart it.
Advantage of LiDAR Technology
Higher accuracy
Fast acquisition and processing
Acquisition of 1000 km2 in 12 hours.
DEM generation of 1000 km2 in 24 hours.
Minimum human dependence
As most of the processes are automatic unlike
photogrammetry, GPS or land surveying.
Weather/Light independence
Data collection independent of sun inclination and at night
and slightly bad weather.
Canopy penetration
LiDAR pulses can reach beneath the canopy thus
generating measurements of points there unlike
photogrammetry.
Higher data density
Up to 167,000 pulses per second. More than 24 points per
m2 can be measured.
Multiple returns to collect data in 3D.
Additional data
LiDAR also observes the amplitude of back scatter energy
thus recording a reflectance value for each data
point. This data, though poor spectrally, can be used for
classification, as at the wavelength used some features
may be discriminated accurately.
Cost
Is has been found by comparative studies that LiDAR
data is cheaper in many applications. This is particularly
considering the speed, accuracy and density of data.
References
• http://sisko.colorado.edu/NOTES/Lecture11.pdf
• http://geography.tamu.edu/class/aklein/geog361/lecture_notes.html
• http://home.iitk.ac.in/~blohani/LiDARSchool2008/Downloads/Kanpur-Baltsavias.pdf
• http://en.wikipedia.org/wiki/Lidar
• http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=1689630&url=http%3A%2F%
2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D1689630
THANK YOU