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’ ConferenceMay 2, 2006

Broomfield, Colorado

Gerald Dittberner (NOAA), Ph.D., CCM, FRMetS

Advanced Systems Planning Division

NOAA Satellite and Information ServicePoster 54

MEO

Medium Earth Orbitfor

Continuous Polar Winds

MEO

Medium Earth Orbitfor

Continuous Polar Winds

This work was performed byAndrew J. Gerber, Jr., David M. Tralli, and Francois Rogez,

Jet Propulsion LaboratoryThe California Institute of Technology

With support from NOAA

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The Grand Vision

• Measure anywhere on the globe, anytime, with any repeat time, and distribute data to anywhere in near real time

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Parameter NPOESS MEO GEO

Altitude 833 km 10,400 km 35,786 km

Period 101 Min 6 hours 24 hours

Returns to same Longitude

~12 hours 8 hours Always Visible

Ground Motion 400 km/min 83 km/min 0 km/min

MEOOrbit

Basics

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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

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Step 2 – MEO-GEO ConstellationConcept

MEO-GEO Constellation: 3 LEO Polar satellites 4 MEO Polar Satellites 5 GEO Satellites

Complete set of 4 MEO in 90 Degree orbitContinuous Polar WindsRisk ReductionFull Global Coverage (4-pi Steradian)Complements International Geo RingSupports GEOSS

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Step 2 – MEO-GEO Constellation Coverage of Pole and Northern Europe

Any location continuously visible by one or more MEO or GEO satellites

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Percent Time Target in View 4 MEO

GeoSTARGeoSTAR

A Microwave SounderA Microwave Sounderforfor

GEO OrbitGEO Orbit

GeoSTARGeoSTAR

A Microwave SounderA Microwave Sounderforfor

GEO OrbitGEO Orbit

This was performed by:Bjorn Lambrigtsen (Lead), Shannon Brown, Steve Dinardo,

Pekka Kangaslahti, Alan Tanner, and William Wilson ofThe Jet Propulsion Laboratory, California Institute of Technology;

Jeff Piepmeier, GSFC; and Chris Ruf, U. MichiganThat was partially funded by NOAA

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GeoSTARGeoSTARA Microwave Sounder for GOES-RA Microwave Sounder for GOES-R

National Aeronautics and Space Administration

Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadena, California

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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

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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

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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

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Solar Transit: Reconstructed Tb Images

Sun isabout

4000 Kin this

50-GHzchannel

Timesin

PDT

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Accommodation Studies

Array arms folded for launch Stowed in Delta fairing Deployed on-orbit

Ball Aerospace

Backup Charts

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The Molniya Orbit: Northern Points =180 degrees apart

Anchorage*~150 Deg W

Helsinki~ 30 E

*Launch to ensure coverage of Alaska and N. Europe

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NGOESS Robustness24 Hour Average Cover Percent

With only 3 Satellites Operational in Each Orbit Plane

Spacecraft: 3 equ + 3 pol Planes: 2Inclination: 0 / 90deg

Altitude: 10.4k kmSeparation: 120 deg each orbitElevation Limit: 5 deg

24hr Average Coverage Percent

Epoch: 1998/09/10 22:02:52

sat H e i

e1 10400 0 0 0 0 0

e2 120

e3 240

p1 90 -35 0 0

p2 120

p3 240

FR 20050311

19Still

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Radial Resolution: As a Function of Ground Range

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

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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 = 1.0020 deg El. PAR = 2.92 5 deg El. PAR= 11.5

Pixel Aspect Ratio (PAR) PAR = Radial/Perpendicular

@ Nadir PAR = 1.0020 deg El. PAR = 2.92 5 deg El. PAR= 11.5