1. Assimilating Data Into Ionospheric Models: The Real-Time Revolution Anthony Mannucci, JPL Brian Wilson, JPL George Hajj, JPL, USC Lukas Mandrake, JPL Xiaoqing Pi, JPL, USC Chunming Wang, USC Gary Rosen, USC National Reconnaissance Office Technology Seminar July 11, 2005 JPL/USC GAIM [Tony.Mannucci@jpl.nasa.gov] Part I

2. NRO Technology Seminar July 11, 2005 Density Comparison: Troposphere~1x10 -3 g/cm 3 Ionosphere~2x10 -14 g/cm 3 Motivation: Ionospheric Effect on GPS Signals Iono Tropo GPS Receiver 350 km 1 km

3. NRO Technology Seminar July 11, 2005 Ionospheric Delay Versus Frequency 1 TECU = 10 16 el/m 2 Delay = 40.3 TEC/f 2 Leading term only…

4. NRO Technology Seminar July 11, 2005 Raypath Bending Radio signal path depends on detailed ionospheric vertical and horizontal structure HF communications Over-the-horizon radar

5. NRO Technology Seminar July 11, 2005 Raypath Bending Versus Frequency Approximate Formula Millman and Reinsmith Elevation Angle: Apparent Elevation Change (Degrees)

6. NRO Technology Seminar July 11, 2005 NASA Application: Deep Space Tracking S-band 2 GHz X-band 8 GHz Effect of media on tracking observables must be calibrated How to do it robustly and accurately?

7. NRO Technology Seminar July 11, 2005 Remove “average” delay –Climatology (physics or data-based) –Not sufficiently accurate due to “weather” Self-calibrate –Use dual-frequency tracking observables Acquire real-time measurements –Most accurate approach –Requires measurements and model that is updated by data Calibrating Media Effects

8. NRO Technology Seminar July 11, 2005 Improving Global Delay Estimates Iijima et al., Journal of Atmospheric and Solar-Terrestrial Physics, 1999 Ionospheric Specification and Determination Workshop, JPL 1998 Non-data driven (IRI-95) Data driven (GIM) Global GPS Receiver Network Global Ionospheric Map Low Solar Activity (1998)

9. NRO Technology Seminar July 11, 2005 Improving Vertical Profiles Six-satellite COSMIC constellation Launch late 2005 Low-Earth Orbiter GPS 3000 profiles/day Electron Density Profile COSMIC coverage

10. NRO Technology Seminar July 11, 2005 Latency of Electron Density Profiles COSMIC data latency (courtesy of Chris Rocken, UCAR)

11. NRO Technology Seminar July 11, 2005 USC/JPL Global Assimilative Ionosphere Model (GAIM)

12. NRO Technology Seminar July 11, 2005 Ionospheric and Atmospheric Remote Sensing Group at JPL Global Ionospheric TEC Mapping (GIM) –First ever global TEC map (1993) –SATLOC wide-area differential GPS (1996) – real-time, regional –FAA wide-area augmentation system 1996-on –Naval Oceanographic Office: ionosphere calibrations for GEOSAT Follow-On mission daily –By-product: provide satellite calibrations (T gd ) to GPS Project –By-product: algorithm adopted by DoD contractors Ionospheric data systems for R&D –Real-time/near real-time TEC products from GPS global network –GPS TEC sent to Air Force Weather Agency Model assessment –Ionospheric Network Analysis –Data-Driven Ionospheric Calibration Experiment (DICE) Model development – Global Assimilative Ionosphere Model –AFOSR/ONR-sponsored MURI 5-year development program C/NOFS augmentation: C/NOFS data into GAIM

13. NRO Technology Seminar July 11, 2005 AFRL Collaboration (Task manager: Bill Borer) C/NOFS satellite: Goal is forecast of scintillation Investigating use of GAIM for background density field Critical for accurate forecasts Input C/NOFS Datatypes: GPS occultation In situ density Vector Electric fields, vertical drift velocity Tri-band beacon (ground-LEO TEC links) Close collaboration Source code transfer Jointly-conducted analysis Technology transfer (source code, expertise, data sets…) C/NOFS Augmentation Effort

14. NRO Technology Seminar July 11, 2005 Accurate deep-space navigation Accurate deep-space navigation Civil-aircraft navigation/landing Civil-aircraft navigation/landing Ocean topography Satellite instruments Ocean topography Satellite instruments Communications, Navigation, Radar, Surveillance Communications, Navigation, Radar, Surveillance New measurements Applications Deep-space tracking Global-scale calibration Space environment Applications of Data-Based Ionospheric Calibrations Scientific Research Regional-scale calibration Requirements Driver Products/Obs Line-of-sight slant delay Regional TEC maps Error bounds Global TEC maps Tracking and sensor corrections GPS ground and space, in-situ, TEC beacons, sondes, UV  GAIM

15. NRO Technology Seminar July 11, 2005 JPL Products and Users Global Ionosphere Maps (Vertical TEC or Delay) Near Real-time Total Electron Content Global Assimilative Ionosphere Model Algorithms Studies Electron Density Profiles FAA Deep space navigation GEOSAT Follow-on GPS augmentation Wide-area Local-area Ionospheric Network Analysis DICE Data-driven iono cal expt Hourly & 5- min TEC to AFWA Orbits for TDRSS etc. Space Env Sensor Study Space science (proposed) Develop GAIM @ USC & JPL CNOFS augmentation DoD Products DoD NOAA Navy AFOSR/ONR