NASA Man-Made Noise Floor Study Summary Program Results

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NASA Man-Made Noise Floor Study Summary Program Results. National Spectrum Managers Association May 25, 2005 James E. Hollansworth NASA Headquarters. Measurements of Man Made Spectrum Noise Floor. Rationale & Objective:
NASA Man-Made Noise Floor StudySummary Program ResultsNational Spectrum Managers AssociationMay 25, 2005James E. HollansworthNASA HeadquartersMeasurements of Man Made Spectrum Noise Floor
  • Rationale & Objective:
  • In many instances new wireless technologies support applications in unlicensed bands or “underlay” existing services on an unlicensed basis.
  • This could result in a degradation of the noise-floor environment.
  • There is a need to examine whether the observed noise floor results are consistent with applicable regulations governing those bands
  • NASA is particularly concerned with noise floor in bands used for crucial safety and scientific purposes
  • NASA Partnership with the Department of Transportation, Clemson University, & Stanford University
  • Funding by NASA and DOT
  • Published as NASA CR-2004-213551, available at
  • Stanford University conducted a survey in the L1-Band (1563.42 - 1587.42 MHz), Unified S-Band (2025-2110 MHz), and Industrial Scientific and Medical Band (2400 - 2482.5 MHz)Clemson University conducted a survey in the Passive Sensing Band (23.6 – 24.0 GHz)L1 - BandS - Band2.4 ISM -BandPassive Sensor BandMeasurements of Man Made Spectrum Noise FloorMeasurements of Man Made Spectrum Noise Sample Survey: San Jose Downtown, CA GPS L1 Band Measurements Equipment and LocationGPS L1-Band Temporal, Spectral, Angular, & Statistical AnalysisKeySignificantly greater than natural noise powerSlightly above the natural noise powerIndistinguishable from the natural noise powerStanford Measurement Results
  • Stanford University Survey Results
  • The GPS L1 Band is relatively pristine and quiet
  • The Unified S Band has emissions due to non-Government services
  • The 2.4 GHz ISM Band is discernibly noisier than regulated bands
  • Urban areas are noisier than rural environments
  • Airports and harbors are generally similar to urban areas
  • Average Received Power (in dBm/MHz)Clemson Measurement Results
  • Clemson University Survey Results at 24 GHz
  • Overall no appreciable levels of man-made radiation
  • Nineteen spectral peaks were, however, detected at two airport sites
  • 3 in a single frequency at Hartsfield Jackson Airport
  • 10 at the Oconee County Airport
  • Anomalies possibly related to satellite service to commercial trucks
  • Conclusions
  • In bands open to public utilization, the power spectrum is far above the thermal noise floor
  • In restricted bands the power spectrum is close to the thermal noise floor
  • Current rules appear to be effective in determining the radio environment
  • Future regulations should be sensitive to the function of each band:
  • Each band supports different types of applications
  • Some bands support critical systems and cannot tolerate operational failure and need to be protected from any interference
  • Other bands can tolerate a certain level of interference while requiring more bandwidth
  • Restricted bands should not be considered for operations of unlicensed and unregulated services
  • For additional information contact:James E. Hollansworth (Jim)NASA Headquarters(202)
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