ARL Applied Research Laboratories The University of Texas at Austin ARL Applied Research Laboratories The University of Texas at Austin Ionospheric Tomography Network of Egypt T W Garner Applied Research Laboratories University of Texas at Austin A M Mahrous Space Weather Monitoring Center Helwan University

ARL Applied Research Laboratories The University of Texas at Austin Ionospheric Tomography Network of Egypt Chain of 3 CIDRs in Egypt as part of ISWI Only 1 is operational right now Located at different university campuses across Egypt. Operated jointly by Helwan University (Ayman Mahrous) and ARL:UT (Trevor Garner)

ARL Applied Research Laboratories The University of Texas at Austin UHF/VHF Satellite Radio Beacons  Transit-  First satellite navigation system  Satellites in LEO (~1000 km), polar orbit  Transmitted navigation message at 150 and 400 MHz  Doppler shift of the signals used for positioning  Decommissioned in 1989 to the Navy Ionospheric Monitoring System (NIMS)  4 Active beacons  Other US Radio Beacons-  Several DoD missions have flown a NRL-developed radio beacon  C/NOFS, DMSP F15, Radcal  Several other nations have flown or will fly radio beacons  COSMIC, ePoP, future Brazilian and Indian missions

Coherent Ionospheric Doppler Receivers (CIDRs)  Designed to track 150/400MHz LEO beacons (Transit/NIMS, GFO)  Provides relative TEC and phase scintillation measurements  Useful for examining spatial structure with a relatively sparse receiver network and conducting ionospheric tomography 30 meter RF cable 150 MHz 400 MHz PCRX

ARL Applied Research Laboratories The University of Texas at Austin CIDR measurements  Doppler shift in both the 150 and 400 MHz channels  Linear combinations of these two Doppler shifts produce three separate ionospheric measurements  STEC/  t  Ionospheric δf at 150 MHz  Ionospheric δf at 400 MHz  The  STEC/  t can be integrated to a STEC under the satellite  All three measurements can be binned and RMS values used to characterize the scintillation

ARL Applied Research Laboratories The University of Texas at Austin Ionospheric Doppler Shift

ARL Applied Research Laboratories The University of Texas at Austin Dual Frequency Combinations  Most existing UHF/VHF beacons transmit at 8/3  There are 2 basic linear combinations for dual frequency Doppler measurements

ARL Applied Research Laboratories The University of Texas at Austin Scale of CIDR measurements  For a typical beacon satellite orbit, the satellite crosses a full field of view in 20 minutes.  Corresponds to an arc distance of ~0.15 o in 1 second  The CIDR are sensitive to smaller-scale structures  At 1 Hz: F-region structures (300 km) ~1570 m E-region structures (100 km) ~525 m  Limited by the Fresnel Scale F-region Fresnel Scale ~ m E-region Fresnel Scale ~ m 

ARL Applied Research Laboratories The University of Texas at Austin Features of UHF/VHF Beacon Electron Content Measurements  Spacecraft cross the field of view in ~20 min (GPS spacecraft take ~8hrs)  Enable tomographic reconstruction  Measurements from LEO spacecraft (~1000 km)  Purely ionospheric measurement  Shorter frequencies (400 MHz vrs MHz)  More precise TEC measurements  TEC ~  /f 2  CIDR ~ 15.5 more precise than GPS

ARL Applied Research Laboratories The University of Texas at Austin More Differences Between GPS and CIDRs  Tend to have a higher data rates  1 kHz decimated to 1-10 Hz  Allows measurements of the rapid ionospheric variations  Relative TEC measurements  Relative to an unknown integration constant  GPS TEC relative unknown transmitter and receiver biases

ARL Applied Research Laboratories The University of Texas at Austin CIDR Data Chain  Receiver records the raw Doppler measurements  Postprocessing code quality checks the Doppler measurements, calculates the positioning solutions, and converts the Doppler measurements to  TEC/  t and TEC

Sample Doppler File # # Operational1 # #

Sample Processed Text File # GLOBAL ATTRIBUTES -- name : value CONTACT : Trevor Garner, ARL:UT, CREATOR : Kanish Mehta SOURCE : Applied Research Laboratories: University of Texas at Austin instrument : ARL:UT CIDR Receiver # 26 receiver_location : Helwan receiver_latitude : receiver_longitude : receiver_altitude : sample_rate_hz : 1 satellite_name : OSCAR 32 num_data : 643 # UT Relative TEC Rate Sat.Lat Sat.Lon Sat.Alt Azimuth Elevation F Lat F Long E Lat E Lon Phase Rate Phase Rate Sat.Vel Good # (sec) TEC (TECU) (TECU/1.00s) (deg) (deg) (km) (deg) (deg) (deg) (deg) (deg) (deg) VHF (Hz) UHF (Hz) (km/s) Flag

ARL Applied Research Laboratories The University of Texas at Austin Sample ITNE Observation

ARL Applied Research Laboratories The University of Texas at Austin ITNE Science Goals  Large-scale plasma structures  Chain is located underneath of equatorial fountain peaks (15.6 to 23.8 deg magnetic latitude)  Routine observations of the equatorial fountain peaks  Tomography and data assimilative reconstructions of the fountain  Small-scale plasma irregularities  TEC variations associated with equatorial anomaly peaks  Examine the consequence with tropospheric weather  Comparison with the American sector CIDR chain  Examine the impact of greater geographic/magnetic latitude offsets in the Americas

ARL Applied Research Laboratories The University of Texas at Austin Analysis of Sample Observation

Ionospheric Tomography  Traditional usage of the CIDR-like measurements  Utilizes crossing ray paths  Typically 3-5 receivers along aligned with the orbit  Assumes a slowly varying ionosphere  Typically 15 minute time steps

ARL Applied Research Laboratories The University of Texas at Austin Contact Information  If you are interested in working with ITNE data, please contact:  Ayman Mahrous  Trevor Garner

ARL Applied Research Laboratories The University of Texas at Austin Summary  First ITNE CIDR is up and running  First results of Coherent Ionospheric Doppler Receiver measurements over Egypt, Mahrous, A., A. Shimeis, and T. Garner, Space Weather, 8, doi: /2009SW000548,  Excellent opportunity to study the northern crest of equatorial fountain in Africa  Please contact or if you think ITNE data can help in your data study.