Simple Radar Modeling and Simulation in ArcGIS

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Simple Radar Modeling and Simulation in ArcGIS

• John Maschmeyer

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Motivation

• Scenario
• Radar Platform on Plane
• Searching for Targets on Ground
• Problem
• Return Signal Received from both Target and
  surrounding Terrain
• This Clutter makes target detection more
  difficult
• Solution
• Build Model of Clutter to improve detection
  performance

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A Quick Overview of Radar

• Basic Idea
• Platform Transmits an Electro-Magnetic Signal
• Signal Bounces off of Objects
• Platform measures Return Signal
• Important to Note
• Range can be determined by measuring the time
  delay of the return signal
• Return signal is just a scaled version of the
  transmit signal
• Amplitude of the Receive Signal is a function of
  the scattering function of the target, the area
  of the target, and the range to the target

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More Background

• Can also measure Doppler shift if target is
  moving relative to platform
• Platforms use multiple receive antennas to help
  determine direction to target
• To simplify, neither of these components were
  modeled in ArcGIS

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Context
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Data

• Small Region surrounding the Lake of the Ozarks
• Elevation Data
• 30 m Resolution
• USGS Seamless Data Server
• Used for Geometry Factors
• Land Use Data
• 30 m Resolution
• USGS Seamless Data Server
• Used for modeling the scattering function

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Methods

• Modeling Goal
• Compute the Receive Amplitude for each grid cell
  in the target area
• Requires 3 Components
• Range
• Scattering Function
• Effective Area of Cell
• Simulation
• Add targets to model
• Add random component
• Perform Simple Detection

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Range

• Using spatial analyst distance function, obtained
  distance from platform to each grid cell
• Distance computed in Degrees, Converted to Meters
• Only provides 2d distance
• Compute 3rd Dimension distance with Raster
  Calculator (Altitude)

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Scattering Function

• Simple Reclass of Land Use Raster
• Values somewhat arbitrary
• Actual Values would stem from direct measurements

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Effective Area

• Find Area of Grid Cells as seen by Platform
• Viewshed to Remove Hidden Grid Cells (Not used
  due to ArcGIS issues)
• Area Effective height x Effective Width
• Height
• Based on Slope
• Width
• Based on Aspect

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Finding Effective Height

• Compute Slope of Elevation Raster
• Solve Geometry Problem

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Finding Effective Width

• Compute Aspect, Direction to Platform
• Need to 0 out all grid cells that are facing away
  from platform

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More Maps
Effective Area
Range
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Finishing Up

• Compute Modeled Amplitude
• Create Simulated Data
• Add targets to Sigma values
• Add Random Noise
• Target Detection
• Find Error Simulated Modeled
• Large Errors Represent Targets
• Attempted Threshold Detection and Kernel Function

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Results
Simulated Return
Modeled Return
Error
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Results

• Modeling
• Complete Success
• Simulation
• Noise Levels Too High
• Targets too dim
• Detection
• Needs more work

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Future Work

• Improve Initial Simulation/Detection
• Compare More Detection Methods
• Incorporate Doppler and Multiple Receive Antennas
  into model
• Explore ArcGIS Modeling Capabilities

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Questions?