Launch Radar Analysis Using STK

1
Launch Radar Analysis Using STK

• Bill Napier
• Launch Test Range Systems Engineer

2
Overview Launch Test Range Systems

• The LTRS supports launches on the USAF Eastern
  and Western Ranges

WR
ER
GPS-Based LTRS Requires Enhanced Radar
Architecture
3
Radar Systems Analysis

• LTRS Radar Mission

• Space Object Identification
• Intercept Scoring
• Kill/Lethality Assessment

• Range Safety
• Vehicle GPS Flight Validation
• Boost Phase Debris
• New Foreign Launches

• Launch Vehicles Mission Profiles

• Expendable Delta, Pegasus
• NASA STS / Future CEV

• Evolvable Delta IV, Atlas V

• Analysis process established with STK as the
  important cornerstone of the work effort

Analysis Is critical for an Optimized Radar System
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STK Methodology
STK models Performance and Operational
Effectiveness
5
Launch SRB Modeling

• Electromagnetic wave propagation can be severely
  affected by the exhaust plasma from launch
  vehicle solid rocket boosters
• Degrades radar signals as launch vehicles move up
  and away
• Reflective RCS dominated by unburned Al2O3
  propellant (Slag)

Aspect Angles drives a Radar Location Solution
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STK Coverage Products

• Launch Aspect Angle Graphs (MATLAB)
• Depicts each site location aspect angle relative
  to vehicle as a function of flight
• Plume attenuation effect occurs when the site
  line is below the threshold angle
• Applies until T130 seconds except for
  Ballistics/Pegasus, which applies until end of
  coverage
• Mission Expected Coverage Plans (Excel)
• Depicts each site locations vehicle
  line-of-sight and plume effect periods
• Constrained to 1.5 degrees elevation
• Radar and Telemetry Systems similarly affected
  by plume

Plume Effect Zone
Plume Angle Constraint
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STK Radar Model

• Launch vehicle
• Constant RCS 0 dBsm
• -4dB Atmospheric Constant

• Radar Open Systems Control Group
• Fixed 160Hz PRF
• Fixed 16 Pulse Integration
• 12 or 25 microsec. Pulse Width
• 1E-8 False Detection Probability

• Antenna
• 16, 29, 50 Foot Diameter
• 320 Degree K System Temp

• Transmitter
• 5.69 GHZ
• 2 MW Peak Power

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STK Radar Module SNR

• STK Signal to Noise Ratio data is exported to
  Excel
• Quantifies radar skin track performance
• Predicts quality skin track coverage during boost
  phase
• Provides a valuable site comparison of radar
  performance

Selected Radar Sites

• Acquisition Radar in Plume
• Offset Radar Skin Metric Tracking

All Radars providing metric skin track after SRB
drop
STK Process Provides a Radar Set Selection
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STK Author / Viewer

• Provides a dynamic evaluation of radar
  performance
• Visual verification of launch vehicle coverage
  and plume effects

WR Delta IV
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STK Analysis and Radar Selection

• Operational Efficiencies achieved through STK
  Analysis
• Maximum flight coverage period Early acquisition
  
• Minimum plume effect Least sensitivity to
  exhaust flame effects and slag
• Maximum obtainable radar SNR Quality range
  safety/user data
• Best overall utilization Multiple mission
  redundant coverage (in-close off-set radars)
• Radar Selection Considerations
• GPS Metric Track risk mitigation
  Concept-of-Operations
• Standardization of sub-systems (Antenna,
  Transmitter, Control Group)
• Prioritizes for

• GPS Range
• Range Safety

• RMA data
• Cost/Schedule

Siting Analysis Criteria and Radar Selection
Process Inputs to the Final Radar Architecture
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Conclusion

• STK-Derived Radar Architecture
• Substantial Radar Quantity Reduction
• Reduced Acquisition and Life Cycle Costs
• Enhanced Utilization in a GPS-based Range
• Team Acknowledgments
• Doug Barnes Radar Program Manager
• Ray Cutshaw Radar Group Supervisor
• Charles Mouille Radar Systems Engineer

STK combined with System Engineering
Processes Ensures an Optimum LTRS Range Radar
System