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Determining location with diffraction propagation
Micah Taylor2008-10-13
http://kixor.net/school/2008fall/comp790/project/
Localization
Localization
• Finding location relative to wave source
Localization
• Finding location relative to wave source– Cell phones
Localization
• Finding location relative to wave source– Cell phones– GPS
Localization
• Finding location relative to wave source– Cell phones– GPS– Much work in robotics
Types of propagation
RF propagation
• Direct– From source to receiver– Strongest
RF propagation
• Direct– From source to listener– Strongest
• Reflection– Bounces off things– Multipath
RF propagation
• Direct– From source to listener– Strongest
• Reflection– Bounces off things– Multipath
RF propagation
• Direct– From source to listener– Strongest
• Reflection– Bounces off things– Multipath
• Diffraction– Travel around buildings– Multipath
Diffraction
Diffraction
• Bending around objects
Diffraction
• Bending around objects
• Allows out of LOS paths
Diffraction
• Bending around objects
• Allows out of LOS paths
Diffraction
• Bending around objects
• Allows out of LOS paths
• Very important for signalin cities!
Diffraction research
Diffraction research
• Huygens’ diffraction
Diffraction research
• Huygens’ diffraction
Diffraction research
• Huygens’ diffraction
• Several models
Diffraction research
• Huygens’ diffraction
• Several models– Huygens-Kirchhoff– Fresnel– GTD– UTD– BTM
Frustum tracing
Frustum tracing
• No complicated wave effects
Frustum tracing
• No complicated wave effects
• Uses geometry to estimate propagation
Frustum tracing
• No complicated wave effects
• Uses geometry to estimate propagation
• Models propagation
Frustum tracing
• No complicated wave effects
• Uses geometry to estimate propagation
• Models propagation– Stronger in LOS– Bounces
Frustum tracing
• No complicated wave effects
• Uses geometry to estimate propagation
• Models propagation– Stronger in LOS– Bounces
• Discrete volumes
Advantages
Advantages
• Very fast
Advantages
• Very fast
• Supports moving objects
Advantages
• Very fast
• Supports moving objects
• Different materials
Advantages
• Very fast
• Supports moving objects
• Different materials
• Convincing results
Advantages
• Very fast
• Supports moving objects
• Different materials
• Convincing results
• Runs on ordinary PC
Other work
Other work
• Raytracing
Other work
• Raytracing– Dynamic/complex scenes– Slow and aliases
Other work
• Raytracing– Dynamic/complex scenes– Slow and aliases
Other work
• Raytracing– Dynamic/complex scenes– Slow and aliases
• Beam tracing
Other work
• Raytracing– Dynamic/complex scenes– Slow and aliases
• Beam tracing– Fast without aliasing– Static/simple scenes
Other work
• Raytracing– Dynamic/complex scenes– Slow and aliases
• Beam tracing– Fast without aliasing– Static/simple scenes
Other work
• Raytracing– Dynamic/complex scenes– Slow and aliases
• Beam tracing– Fast without aliasing– Static/simple scenes
• Frustum tracing
Other work
• Raytracing– Dynamic/complex scenes– Slow and aliases
• Beam tracing– Fast without aliasing– Static/simple scenes
• Frustum tracing– Some aliasing
Goals
Goals
• Combine RF diffractionwith frustum tracing
Goals
• Combine RF diffractionwith frustum tracing
• Find possible paths throughenvironment
Goals
• Combine RF diffractionwith frustum tracing
• Find possible paths throughenvironment
• Attempt localization usingpath attenuation
