1 UNCLASSIFIED – FOUO – Not for Public Release Operational Space Environment Network Display (OpSEND) & the Scintillation Network Decision Aid Dr. Keith Groves, Prog Mgr Ionospheric Impacts to RF Systems Space Vehicles Directorate Air Force Research Laboratory

2 UNCLASSIFIED – FOUO – Not for Public Release Disturbed Ionospheric Regions and Systems Affected by Scintillation SATCOM AURORAL IRREGULARITIES GPS PLASMA BUBBLES GPS SATCOM MAGNETIC EQUATOR DAYNIGHT EQUATORIAL F LAYER ANOMALIES SBR POLAR CAP PATCHES

3 UNCLASSIFIED – FOUO – Not for Public Release Operational Space Environment Network Display (OpSEND) OpSEND incorporates state-of-the-art sensors, models, and display tools to generate Space Weather impact maps : – UHF Satellite Communication (SATCOM) Scintillation Map – HF Illumination Map – Radar Auroral Clutter Map – Estimated GPS Single-Frequency Error Map OpSEND team received Air Force Merewether Award UHF SATCOM Scintillation Map GPS Single-Frequency Error Map HF Illumination MapRadar Auroral Clutter Map

4 UNCLASSIFIED – FOUO – Not for Public Release Radar Auroral Clutter Ionosphere GPS UHF SATCOM GPS 1-Freq Error HF Illumination COMM NETS Ionosonde Network foF2 TEC and Scintillation Magnetometer Network DMSP OpSEND System Architecture UHF Scintillation Operational, Real-time Assimilation Models AFWA Sensors Space Weather Impact Maps Magnetic Activity SCINDA/IMS Network

5 UNCLASSIFIED – FOUO – Not for Public Release SCINTILLATION NETWORK DECISION AID (SCINDA) Ground-based sensor network – Passive UHF / L-band /GPS scintillation receivers – Measures scintillation intensity, eastward drift velocity, and TEC – Automated real-time data retrieval via internet Data drives assimilative/empirical model providing simplified visualizations of scintillation disturbances – Output spans frequencies from 200 MHz to 2 GHz Graphical output tailored to specific applications (UHF SATCOM, at present) A regional nowcasting system to support users of space-based RF communication and navigation systems

6 UNCLASSIFIED – FOUO – Not for Public Release Scintillation Map SCINDA User Product Example Scintillation Warning Areas Watch Areas

7 UNCLASSIFIED – FOUO – Not for Public Release Present and anticipated thru 2008* SCINDA Ground Stations 30N 0 30S 210E 240E 270E 300E330E 0 30E 60E90E120E 150E Existing SitesUN IHY SitesOther/collaboration *Future sites shown represent approximate desired locations; actual sites TBD

8 UNCLASSIFIED – FOUO – Not for Public Release GPS Positioning Errors During Solar Max Scintillation can cause rapid fluctuations in GPS position fix; Typical night from recent field experiments Scintillation can cause rapid fluctuations in GPS position fix; Typical night from recent field experiments

9 UNCLASSIFIED – FOUO – Not for Public Release Summary Ionospheric scintillation occurs routinely at low latitudes independent of magnetic activity Scintillation can affect the performance of space-based communication and navigation systems operating at frequencies below about 2 GHz Scintillation affects 2-frequency GPS systems, but no error- estimation model currently exists Exploiting collaborations with international partners and the UN, AFRL plans to add new ground stations over the next three years Coordination with C/NOFS equatorial satellite planned to maximize scientific contribution to understanding Spread F Ground-station support leveraged across AFRL, AFOSR, AFWA and NSF

10 UNCLASSIFIED – FOUO – Not for Public Release Why Africa? Historical ground-based data sets are sparse/non-existent –Ground-based observations critical to understanding scintillation environment ROCSAT in situ (600 km) observations indicate frequent F region irregularities –Activity present nearly year-round DMSP observations show similar peak in bubble occurrence (Huang et al 2004) Goal is to characterize irregularity development over Africa in the context of global patterns of scintillation occurrence Adapted from S.Y. Su, 2005 Fundamental gap in knowledge of the space environment over Africa

11 UNCLASSIFIED – FOUO – Not for Public Release Space Science across Africa UN Basic Space Science Initiative (BSSI) focused on IHY Currently establishing contacts through academia, international partners, US State Department, etc. AFRL to participate in UN- sponsored Nov. workshop to identify host nation partners Goal is to establish robust monitoring network with scientific collaboration across Africa and Asia AFRL hopes to develop 5-8 new sites in Africa over the next 3 years

12 UNCLASSIFIED – FOUO – Not for Public Release SCINDA Ionospheric Parameter Measurements VHF (~250 MHz) & GPS scintillation parameters – S4 scintillation index – Intensity spectrum – Fading probability density function – Temporal decorrelation of intensity – Data quality flags based upon parameter consistency, and reconciliation between S4 index and the fading PDF Ionospheric zonal drift estimates obtained from VHF spaced antenna observations GPS Total Electron Content (TEC) and phase scintillation data Raw data (10-50 Hz) can be recorded as desired Real-time output from SCINDA sensors includes: