Determining location with diffraction propagation Micah Taylor

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

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 signal in cities!

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

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

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

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

Combine RF diffraction with frustum tracing

Goals Combine RF diffraction with frustum tracing Find possible paths through environment

Goals Combine RF diffraction with frustum tracing Find possible paths through environment Attempt localization using path attenuation