NASA

1
Global Precipitation Measurement Microwave
Imager (GMI)
GMI Instrument Concept and Risk Reduction
Study Kick-off Meeting March 2003
Mark Flaming gilbert.m.flaming_at_nasa.gov
2
Discussion Topics

• Overview of GPM Mission
• Instrument Concept and Risk Reduction Study
• GPM Formulation Office Organization and Points of
  Contact
• Current GMI Acquisition Schedule

3
GPM Reference Concept
Core
Constellation

• Core Satellite
• TRMM-like spacecraft (NASA)
• H2-A rocket launch (NASDA)
• Non-sun-synchronous orbit
• 65 inclination
• 400 km altitude
• Dual frequency radar (NASDA)
• Ku-Ka Bands (13.6-35 GHz)
• 4 km horizontal resolution
• 250 m vertical resolution
• Multifrequency radiometer (NASA)
• 10.7, 19, 22, 37, 85, (150/183 ?) GHz VH

• Constellation Satellites
• Pre-existing operational-experimental dedicated
  satellites with PMW radiometers
• Revisit time
• 3-hour goal at 90 of time
• Sun-synch non-sun- synch orbits
• 600-900 km altitudes

• Precipitation Validation Sites for Error
  Characterization
• Select/globally distributed ground validation
  Supersites (research quality radar, up looking
  radiometer-radar-profiler system,
  raingauge-disdrometer network, T-q soundings)
• Dense frequently reporting regional rain gauge
  networks

• Precipitation Processing System
• Produces global precipitation products
• Products defined by GPM partners

4
Evolution of Precipitation Measurement
Capabilities
SSM/I ERA
GPM ERA
TRMM ERA
Systematic Measurement ERA
EOS ERA
Partner-2
Partner-1
EuroGPM-1
Adjunct Base
AQUA AMSR
US Const
ADEOS-II AMSR
GCOM-B1 AMSR F/O
TRMM TMI PR
GPM Core TMI DPR
NPOESS CMIS
DMSP SSM/I
NPOESS CMIS
DMSP SSMIS
DMSP SSM/I
DMSP SSMIS
NPOESS CMIS
90
98
14
12
10
02
96
00
88
92
94
04
06
08
16
18
Years
Breakthrough
GPM Precursor Experiment
High Spatial-Temporal Resolution Calibrated GPM
Demo
Science Quality Tropical Rainfall Measurements
Reliable Radiometric Rainfall Estimation
Mature Global Precipitation Observing System
5
GPM Era Coverage / 3 hoursCORE, DMSP-F18,
DMSP-F19, Megha-Tropiques, GCOM-B1
6
GPM Core Spacecraft Instruments

• .

GMI Microwave Radiometer
13.6GHz radar (Similar to TRMM PR phased array)
35.5GHz radar (phased array)
7
Illustration of Core Observations
Flight Direction
Dual Frequency Precipitation Radar (DPR)
GPM Microwave Imager (GMI)
Ku-band radar swath width245km
Microwave radiometer swath width 850km
5km
8
DPR/GMI Comparison
GPM PR-A
GPM PR-U
GMI
2.4m
Approximately to scale
9
GPM Mission Overview
Core
DMSP (2)

• International Partners
• GCOMB-1
• Megha Tropiques
• E-GPM

TDRSS
Continuous Science Data
U.S.
Partners
International Partner Operations Center
Command/ Telemetry
White Sands
DMSP Operations
GHCC/MSFC
Per Orbit
Per Orbit
Archive
Global Precipitation Data Processing Center
Validation Data from Supersites
U.S. Mission Operations Center
Coordination
International Partner Mission Operations Center
Ancillary Data Streams
Near Real-Time Rainfall
3-hr Rain Map
IR Data (GOES)
Climate Data
AMSU (POES)
GP Data Virtual Broadcast Network
Continuous Real Time Data Links Once Per Orbit
Data Links Command/Telemetry Links Global
Precipitation Data Processing Center Regional
Data Centers Public Users
Virtual Ground Station
Global Precipitation Network
10

• Instrument Concept and
• Risk Reduction Study

11
ICRR Study Objectives

• Two primary objectives of study are
• Instrument Concept
• Develop an Instrument Concept which provides
  confidence that
• Minimum performance requirements will be
  satisfied
• Accommodation requirements are
• Compatible with available resources, and
• Accurately reflect requirements for the completed
  instrument.
• Risk Reduction
• Goal is to have a low risk Phase B/C/D
  Procurement, and to demonstrate at the conclusion
  of the ICRR Study that
• Risks have been identified,
• Risk mitigation plans have been developed and
  initiated, if required.

12
ICRR Study

• Key Study Requirements
• Instrument Concept to conform to the requirements
  contained in the GMI Requirements Document
• Commonality between Core and Constellation
  instruments
• Minimize cost
• Measurements obtained by the two instruments will
  be very similar
• Minimize use of materials that may survive
  reentry (Titanium, Stainless Steel)
• Design Life 36 months
• Momentum compensation
• Instrument currently is required to provide
  compensation
• GPM is doing a trade to determine whether the
  best system approach is for the spacecraft or the
  instrument to provide the compensation
• Spacecraft Interfaces
• Interfaces shown on the GPM website dated January
  21, 2003 are preliminary, and subject to change
• Anticipate some flexibility with the
  spacecraft-side of the interface during this
  study to accommodate instrument-unique design
  requirements
• Core Spacecraft is planned to be built by NASA at
  GSFC
• Constellation Spacecraft
• GMI is currently the only instrument manifested
• Launch fairing shown in drawings has 1.4 m
  dynamic envelope
• Larger diameter fairing (2.4 m) available, but
  GPM Project incurs additional 3 Million in cost
• If use of 1.4 m diameter fairing presents
  substantial difficulty, advise GPM Project

13
ICRR Study Objectives

• Additional Objectives
• Provide opportunity for contractors to obtain a
  good understanding of NASAs objectives,
  priorities and requirements for GMI
• Good knowledge of NASAs requirements and
  priorities is very important for the Phase B/C/D
  Procurement
• Helps to ensure both the proposed work and costs
  conform accurately to NASAs needs
• Helps to minimize both cost and schedule growth
  during development
• Technical interaction during ICRR Study is
  encouraged,
• We will not make design decisions, influence
  strategy for bidding on the Phase B/C/D
  procurement, etc.
• NASA will protect against cross
  fertilization/technical transfer of ideas
• Provide opportunity for contractors to provide
  comment/recommendations to the key GMI
  procurement documents
• Comments/recommendations are welcome at any time
• Technical Interchange Meeting (TIM) should
  address recommendations as an agenda item
• Schedule Required for Phase B/C/D
• Time required from Contract Award to first unit
  delivery
• Optimum timing for second unit delivery
• Cost Estimate

14
Comments Regarding GMI Observing Channels

• GMI Channel Set
• The minimum recommended set of measurement
  channels are as follows
• 10.65 GHz, VH Pol
• 18.71 GHz, VH Pol
• 23.82 GHz, V Pol
• 36.5 GHz, VH Pol
• 89.01 GHz, VH Pol
• 1 The recommended channels has been moved from
  the TMI 19.35 GHz to 18.7 GHz, and from 85.5 to
  89.0 GHz, in order to use frequency bands
  reserved for Passive Earth Remote Sensing
• 2 Scientists have expressed a preference for
  V-polarization at 23.8

15

• Current GMI Acquisition Schedule

16
3/14/03
2003
2004
2005
2006
2007
2008
2009
CY
4
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
1
2
11/08
Core IT (post GMI Delivery)
4/09
Constellation IT (post GMI
Delivery)
PRELIMINARY Awaiting Final Approval
TIM
ICRR Study
Incorporate TIM Data
Technical Comments into RFP
HQ Acquisition Approval
6/03
Tentative
Final RFP
Release
8/03
2/04
8/04
4/05
5/07
9/07
Draft RFP
Phase B/ C/ D Procurement
for Comment
7/03
Award
PDR
CDR
Unit 1
Unit 2
Delivery
Delivery