1. Advanced Technologies for the GOES-R Series and Beyond: Medium Earth Orbits (MEO) as a Venue for Polar Wind Measurements and Geo Microwave – No Moving Parts Fourth GOES Users’ Conference May 2, 2006 Broomfield, Colorado Gerald Dittberner (NOAA), Ph.D., CCM, FRMetS Advanced Systems Planning Division NOAA Satellite and Information Service Poster 54

2. MEO Medium Earth Orbit for Continuous Polar Winds This work was performed by Andrew J. Gerber, Jr., David M. Tralli, and Francois Rogez, Jet Propulsion Laboratory The California Institute of Technology With support from NOAA

3. 3 The Grand Vision Measure anywhere on the globe, anytime, with any repeat time, and distribute data to anywhere in near real time

4. 4 ParameterNPOESSMEOGEO Altitude 833 km10,400 km35,786 km Period 101 Min6 hours24 hours Returns to same Longitude ~12 hours8 hoursAlways Visible Ground Motion 400 km/min83 km/min0 km/min MEO Orbit Basics

5. 5 Roadmap to the Future: Transition Stages Today –3 LEO Polar –5 GEO (2 U.S.) Step 1: MEO Demonstration –3 LEO Polar –1 MEO Polar –5 GEO Step 2: MEO-GEO Constellation –3 LEO Polar satellites –4 MEO Polar Satellites –5 GEO Satellites Tech Devel & Polar Winds Demo Full Polar Winds & Current GEOs A MEO-GEO-LEO Constellation Fulfilling NOAA’s Evolving Data Needs Today

6. 6 Step 2 – MEO-GEO Constellation Concept MEO-GEO Constellation: 3 LEO Polar satellites 4 MEO Polar Satellites 5 GEO Satellites Complete set of 4 MEO in 90 Degree orbit Continuous Polar Winds Risk Reduction Full Global Coverage (4-pi Steradian) Complements International Geo Ring Supports GEOSS

7. 7 Step 2 – MEO-GEO Constellation Coverage of Pole and Northern Europe Any location continuously visible by one or more MEO or GEO satellites

8. 8 Percent Time Target in View 4 MEO

9. GeoSTAR A Microwave Sounder for GEO Orbit This was performed by: Bjorn Lambrigtsen (Lead), Shannon Brown, Steve Dinardo, Pekka Kangaslahti, Alan Tanner, and William Wilson of The Jet Propulsion Laboratory, California Institute of Technology; Jeff Piepmeier, GSFC; and Chris Ruf, U. Michigan That was partially funded by NOAA

10. 10 GeoSTAR A Microwave Sounder for GOES-R National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California

11. 11 GeoSTAR System Concept Concept –Sparse array employed to synthesize large aperture –Cross-correlations -> Fourier transform of Tb field –Inverse Fourier transform on ground -> Tb field Array –Optimal Y-configuration: 3 sticks; N elements –Each element is one I/Q receiver, 3 wide (2 cm @ 50 GHz) –Example: N = 100  Pixel = 0.09°  50 km at nadir (nominal) –One “Y” per band, interleaved Other subsystems –A/D converter; Radiometric power measurements –Cross-correlator - massively parallel multipliers –On-board phase calibration –Controller: accumulator -> low D/L bandwidth Receiver array & Resulting uv samples Example: AMSU-A ch. 1

12. 12 Measurement Requirements Radiometric sensitivity –Must be no worse than AMSU (≤ 1 K) Spatial resolution –At nadir: ≤ 50 km for T; ≤ 25 km for q Spectral coverage –Tropospheric T-sounding: Must use 50-56 GHz Note: Higher frequencies (118 GHz, etc.) cannot penetrate to the surface everywhere (e.g., tropics) Bottom 2 km (PBL) is the most important/difficult part and must be adequately covered –Tropospheric q-sounding: Must use 183 GHz (AMSU-B channels) Note: Higher frequencies (325 or 450 GHz) cannot penetrate even moderate atmospheres –Convective rain: 183 GHz (AMSU-B channels) method proven –“Warm rain”: 89 + 150 GHz (Grody) - maybe 50+150 Temporal coverage from GEO –T-sounding: Every hour @ 50 km resolution or better –Q-sounding: Every 30 minutes @ 25 km resolution or better

13. 13 GeoSTAR Prototype Development Objectives –Technology risk reduction –Develop system to maturity and test performance –Evaluate calibration approach –Assess measurement accuracy Small, ground-based –24 receiving elements - 8 (9) per Y-arm –Operating at 50-55 GHz –4 tropospheric AMSU-A channels: 50.3 - 52.8 - 53.71/53.84 - 54.4 GHz –Implemented with miniature MMIC receivers –Element spacing as for GEO application (3.5 ) –FPGA-based correlator –All calibration subsystems implemented Now undergoing testing at JPL! Performance so far is excellent

14. 14 Solar Transit: Reconstructed Tb Images Sun is about 4000 K in this 50-GHz channel Times in PDT

15. 15 Accommodation Studies Array arms folded for launchStowed in Delta fairingDeployed on-orbit Ball Aerospace

16. Backup Charts

17. 17 The Molniya Orbit: Northern Points =180 degrees apart Anchorage* ~150 Deg W Helsinki ~ 30 E *Launch to ensure coverage of Alaska and N. Europe

18. 18 NGOESS Robustness 24 Hour Average Cover Percent With only 3 Satellites Operational in Each Orbit Plane Spacecraft:3 equ + 3 pol Planes:2 Inclination:0 / 90deg Altitude:10.4k km Separation: 120 deg each orbit Elevation Limit:5 deg 24hr Average Coverage Percent Epoch: 1998/09/10 22:02:52 satHei  e11040000000 e2120 e3240 p190-3500 p2120 p3240 FR 20050311

19. 19 Still

20. 20 Radial Resolution: As a Function of Ground Range

21. 21 ‘Perpendicular to Radial’ Resolution: As a Function of Ground Range

22. 22 Notes on Resolution The two previous slides show that the distortion of a pixel in the radial direction is a different function of elevation angle than is the distortion in the perpendicular direction. However, at a given ground elevation angle, the pixel aspect ratio (see box to the right), is constant, and not a function of altitude Therefore, the distortion of a pixel as a function of altitude in one direction (e.g. Radial) is proportional to distortion in the other (i.e. Perpendicular) The two previous slides show that the distortion of a pixel in the radial direction is a different function of elevation angle than is the distortion in the perpendicular direction. However, at a given ground elevation angle, the pixel aspect ratio (see box to the right), is constant, and not a function of altitude Therefore, the distortion of a pixel as a function of altitude in one direction (e.g. Radial) is proportional to distortion in the other (i.e. Perpendicular) Pixel Aspect Ratio (PAR) PAR = Radial/Perpendicular @ Nadir PAR = 1.00 20 deg El. PAR = 2.92 5 deg El.PAR= 11.5 Pixel Aspect Ratio (PAR) PAR = Radial/Perpendicular @ Nadir PAR = 1.00 20 deg El. PAR = 2.92 5 deg El.PAR= 11.5