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Radio Frequency Interference Measurement System
For theQuarterly Review of the NASA/FAA Joint University
Program for Air Transportation Research
Thursday April 5th, 2001
Douglas Burch, Undergraduate Research Associate
Avionics Engineering Center
Ohio University, Athens
Project Sponsor: FAA
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Purpose of the RFIMS
Determine and isolate Radio Frequency
Interference (RFI) problems with the
National Airspace System (NAS)
communication and navigation facilities
through in-flight analysis of signal data
collected on an airborne platform.
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Radio Frequency Interference (RFI)Team Capabilities
Airport Airspace Analysis Modeling
- Prediction of interference levels within ILS/VOR/VHF
Communication service volumes.
Technical support for international frequency coordination.
Airborne RF data collection
- Characterization of RF environment through
measurement of signal levels and noise floor.
- Mitigation of ILS/VOR/VHF Comm/GPS RF
interference by determining frequency, type, direction and
ultimately location and cause.
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Airborne Capabilities
Spectrum Analysis
Direction Finding (DF)
Radio Frequency Scanning
GPS Mapping
Signal generation & filtering
Audio & video data recording
Avionic Engineering Center’s Cessna Centurion (C210T) on a Radio Frequency Interference Mission.
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Breakdown of Airborne Capabilities
Radio Direction Finding
Signal Analysis and Measurement
Audio Comparison & Recording
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Radio Direction Finding
DF AntennaDF Receiver
ICOM IC-R8500
To Audio Switching
Audio
DF Bearing Processor
Computer #3
DF Bearing Display & Processor Control
/ RCVR Control
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Four-aerial Adcock Antenna
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DF ReceiverICOM IC-R8500 Communications Receiver
Frequency Range:
0.10000 – 823.99999 MHz
849.00001 – 868.99999 MHz
894.00001 – 1999.99999 MHz
http://www.icomamerica.com/receivers
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Software Control for the Receiver
Software Receiver Control in Sequential Search Mode.
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Software Control for the Receiver
Software Receiver Control in Discrete Search Mode.
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Portable RFIMS Rack
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Software Control for DF Hardware
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RFIMS
ILS Localizer/VOR Receiver
2-Channel Intercom
16-Channel A/D Converter
2 Embedded Systems
RF Control Unit
Spectrum Analyzer
RF Signal Generator
Digital Video Recorder
Digital Altimeter
GPS Receiver
2 Portable Computers
Rack Components External Components
Signals Analysis and Measurement Components
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Signal Analysis and Measurement
Comm. Antenna
NAV Antenna
RF Control and Switching
RF Signal Generator
Comm RCVR
NAV RCVR
Spectrum Analyzer
Digital Video
Recorder
Analog to Digital
Converter
Control from Data Stream Manager (DSM)
From DSM
From DSM
To DSM
To DSMTo Audio Switching
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Spec A / Sig Gen / Receiver
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Control for the Spectrum Analyzer
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Signal Analysis and Measurement Computer Control
Computer #2 Moving Map Display
Data Stream
Manager (DSM)
Digital Meter
Computer #1 Master
Control Data Logging Real-time PlottingComputer #4
Real-time Simulation
Calculations
GPS Antenna
GPS RCVR
Spectrum Analyzer
A/D Converter
Spectrum Analyzer
Control & Switching
RF Signal Generator
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Moving Map Display
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RFIMS Position
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Audio Comparison & RecordingScanner
Antenna #1Scanner
Antenna #2
Scanner Receiver #1
Scanner Receiver #2
Aircraft Intercom
Audio Switching
(Audio I/O)
Two-Channel Audio Recorder
Two-Channel Headphones
ICOM RCVR
COMM RCVR
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Airborne MissionsSignal Analysis and Measurement Missions:
Simulate Signals to determine if they are a possible RFI threat to NAS communication facilities
Measure localizer signal to insure they are in proper working order.
Fly grid patterns to determine antenna coverage of the VOR.
Direction Finding Missions:
Determine and locate RF interference.
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Airborne DF Statistics
Direction Finding Missions:
100 % success rate for RF interference missions.
50% resolved by Direction finding.
50% resolved using Audio Comparison.
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Contact Information
Project Manager: Walter Phipps
Software Engineer: Janet Blazyk
Research Engineer: Kevin Johnson
Undergrad Assistant: Douglas Burch
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Questions?
