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Software-Defined Radios for Polar Science

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Software-Defined Radios for Polar Science Powered By Docstoc
					  40º Magnetic Meridian Remote Measurement Chain
   Bob Clauer, Virginia Tech

• Global Sun-Earth electrodynamic
  and plasma dynamic system
• Utilize 'conjugate' northern and
  southern instrument arrays
   – Greenland
   – Antarctic Plateau
   – Coordinate with other global
     instrument arrays and satellites
• Provide near real time data for:
   – Investigation and analysis
   – Input to space simulation
      codes
• Investigate response of system to
  different solar wind drivers,
  seasons, internal magnetospheric
  preconditions, etc.
 Conjugate
 Aurora                                Much of our ground based research uses
                                       the Greenland arrays of observatories.
                                       The west coast chain of magnetometers is
                                       aligned almost along the 400 magnetic
                                       meridian. To study the interhemispheric
                                       electrodynamic coupling we are working to
                                       establish an Antarctic chain of
                                       autonomous magnetic observatories along
                                       the 400 magnetic meridian. Our prototype
                                       system has been tested successfully at
                                       South Pole during the past 2 years.


The Sun-Earth system is our
laboratory. It is a large
electrodynamic system and the
space weather in this system can
affect many important technologies
upon which our society depends.
It is important to measure the
variations in this system globally.
For example, the ionospheric
boundaries in the summer and
winter hemispheres will have
significantly different conductivity
and this will affect the
interhemispheric electrodynamics.
              Geomagnetic Conjugacy
      Greenland West Coast and Eastern Antarctic
           85




                            75                   
                                                                   
                                                                    A81
                                                                                P3
                                                                 
                                                                         
                                                         
                                                         P2                  
                                                                                 
                                                                 SPA                      P4
                                                                                     P1        VOS
                                                                                               P5


                                                                                                         P6
                       65                                                                                     80
                                    60
                                                                                                        BAS
                                                                             70                          LPMs

     Greenland West Coast                 Eastern Antarctic
     Magnetometer Chain                  Magnetometer Sites
~40 CGM meridian (12 stations)   ~40 CGM meridian (7 - 10 stations)
Modular Low-Power Instrument Platforms

• Presently supports low-power fluxgate
  magnetometer (0.5 Watts).
• Opportunities to support other low-power
  instruments in cluster of platforms.
• Opportunities to enhance existing platform
  with new capability.
  – Software defined radio
  – Modify existing GPS to also do TEC
  – Meteor-burst radio communications (instead of
    Iridium)
Software-Defined Radios for Polar Science
• A software-defined radio replaces special-purpose
  hardware with software running on a general-
  purpose microprocessor or DSP
• Advantages
   – Flexible and easily-customized receiver designs
   – Merging of multiple radios onto one platform
   – Science-grade receivers can be developed at a reduced
     cost with more control over how measurements are made
   – Dynamic control of power consumption is possible
     Example: GPS Software Receiver
• Science Requirements:
   – Accurate TEC measurements (requires dual-frequency
     receiver)
   – 50 Hz Scintillation measurements and weak signal
     tracking
   – Low per unit cost
• Commercial Dual-Frequency GPS Receivers:
   – TEC measurements are excellent
   – Function poorly in weak-signal environments
   – Typically do not provide 50 Hz signal power and phase
     measurements for scintillations
   – Cost $5000 or more
  One Proposed Receiver Design
• Merge science-grade GPS receiver with meteor scatter
transceiver
                                   DSP Processor

     GPS Front               GPS
       End                 Correlator        Tracking Loops,
                                               Navigation
                                                Solution,
                         Meteor Scatter       Science Proc.
                         Comm. Signal
                          Processing


                                    External Input       Time Sync.
            Software Receivers @ VT

• Real-time software receivers
   –   GPS C/A code receiver
   –   GPS C/A + L2C receiver
   –   GPS + Galileo receiver
   –   Run on DSPs or Pentium-class
       processors
• Have Phase-1 STTR with
  Cornell and ASTRA to
  produce ~$1000 science-grade
  dual-frequency GPS software
  receivers.
• Power consumption for GPS
  receiver is around 2 Watts
       SuperDARN Radars and Magnetometers in the Arctic and
                           Antarctic


                                                 NIPR LPM between Syowa & Dome F




                                      Syowa




                                         Virginia Tech LPM test run at South Pole




Existing          Planned

				
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