Usage and Protection of the Earth Exploration Satellite Service J. Piepmeier NASA Goddard Space Flight Center Microwave Instrument Technology Branch Greenbelt, Maryland USA COSPAR Scientific Assembly Montréal July 14, Piepmeier - COSPAR, Montreal

Earth Exploration Satellite Service Since 1972, spaceborne microwave radiometers have provided all-weather day-night observations of our planet Over 25 environmental variables are estimated from microwave data Data used in operational and research weather prediction, climatology research and monitoring, and environmental observation. NASA’s Earth Observing System covers 6.9 GHz – 2.5 THz July 14, Piepmeier - COSPAR, Montreal

JAXA’s AMSR-E on NASA’s EOS Aqua July 14, 2008 Piepmeier - COSPAR, Montreal 3 6.9, 10.7, 18.7, 23.4, 36.5, 89 GHz

Oceanographic Data Products July 14, 2008 Piepmeier - COSPAR, Montreal 4

1998 Hurricane Bonnie

Sea Surface Temperature From TRMM Microwave Imager

1998 Hurricane Danielle Aircraft sortie

Danielle Microwave Imagery (10.7 – 325 GHz) XKwvwv KaKa W Imaged from NASA’s DC-8 and ER-2 on August 30, 1998

Air Temperature Decadal Trend July 14, 2008 Piepmeier - COSPAR, Montreal 9 Decadal trends ( ) in Microwave Sounding Unit channel for Lower Troposphere (~<5km) Temperature ( o C). Data poleward of 82.5° North and 70° South, as well as areas with land or ice elevations above 3000 meters, are not available and are shown in white.

Frequencies for Observing over Ocean July 14, 2008 Piepmeier - COSPAR, Montreal 10

Frequencies for Observing over Land July 14, 2008 Piepmeier - COSPAR, Montreal 11

12 RFI Index: TB 6H - TB 10H Global Radio Frequency Interference (RFI) RFI contamination occurs at both 6.9 GHz (widespread in U.S., Middle East, Asia) and 10.7 GHz (mainly in England, Italy, Japan) MicroRad Rome, Italy Ashcroft/Li/Njoku/Wentz Courtesy: E. Njoku, JPL July 14, 2008Piepmeier - COSPAR, Montreal

RFI in Spaceborne Radiometers Frequency Band Confirmed or Potential InstrumentsNature of RFI L-bandPotential SMOS/MIRAS Aquarius/SAC-D, SMAP Likely to be OOB emissions from terrestrial radars C-band Confirmed Expected SMMR on SeaSat and Nimbus 7 AMSR-E on EOS Aqua WindSat on Coriolis MIS on NPOESS Majority is likely fixed service (FS) communcations. Mobile service (MS) and radiolocation possible. Proliferation of Part 15 UWB devices expected. X-band Confirmed Potential AMSR-E, WindSat GMI on GPM core satellite MIS Allocation shared with FS. WindSat uses extended band up into Direct Broadcast Service (DBS). K-band 24 GHzPotential MIS and GMI ATMS on NPP (and NPOESS) Allocation shared with Fixed Satellite Service (FSS) S-E links and FS. No confirmed cases. Shared with UWB vehicular radars. No RFI experienced. Ka-BandPotentialMIS and GMI Allocation shared with FS and MS. No confirmed cases. V-band PotentialATMS PATH from NRC Decadal Survey Part-15 devices growth explosion expected. Allocation shared with inter-satellite service links visible from GEO. July 14, Piepmeier - COSPAR, Montreal

Engineering Approach – SOE Survivability: avoid damage from RFI Operability –Measure without error in the presence of interference –Receiver selectivity Excisability –Receive interference but can remove it –Detection and excision Spectral (sub-banding) Temporal (pulse blanking) Statistical or amplitude (kurtosis) July 14, Piepmeier - COSPAR, Montreal

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Spectrum Allocation July 14, 2008 Piepmeier - COSPAR, Montreal 17

Terrestrial Long-Range Radars Operate in radio-location service Highest power with widest spectrum List of U.S. L-band radars used –Aerostat (L-88): 12 radars –AN/FPS-108: 1 radar –AN/FPS-117: 31 radars –AN/FPS-124: 39 radars –ARSR-1: 23 radars –ARSR-2: 17 radars –ARSR-3: 14 radars –ARSR-4: 42 radars Multiple military (Army, Navy, USMC) radars not included –No technical data available on most –No location data available on all (mobile) July 14, Piepmeier - COSPAR, Montreal

AN/FPS-108 COBRA DANE worst case = 1 W at Aquarius ~ K MUST LIMIT POWER July 14, Piepmeier - COSPAR, Montreal

Frequency Analysis for Operability How much selectivity is enough? Use worst offender – AN/FPS- 117 within U.S. –25 kW peak (4 kW average) transmitter –39 dBi gain antenna –1383 MHz maximum frequency in NTIA filings Frequency Dependent Rejection method –Transmitter spectrum –Receiver bandpass response –Rejection based on frequency offset July 14, Piepmeier - COSPAR, Montreal

AQUARIUS FPS-117 FDR - 25 MHz BW 7-Pole, 9-Pole & Brick Wall Filter Comparison 1385 MHz 1400 MHz July 14, Piepmeier - COSPAR, Montreal Filtering is not enough!

Aquarius West Coast Path Start: Lat=-125, Lon=-3 deg July 14, Piepmeier - COSPAR, Montreal

AQUARIUS Radiometer Radars start to be visible July 14, Piepmeier - COSPAR, Montreal 0.1 K 0.01 K K

AQUARIUS Radiometer Detect pulses 3 x Nyquist sampling of radar azimuth beam July 14, 2008 Piepmeier - COSPAR, Montreal K 0.01 K K 10 ms

Real Life Aquarius RFI in Ground Experiment July 14, 2008 Piepmeier - COSPAR, Montreal ms integration 2.88-s integration

Prediction is 1000X worse over land! 100 K 10 K 1 K 0.1 K 0.01 K July 14, Piepmeier - COSPAR, Montreal

L-band Interference Suppressing Radiometer Real-time removal of pulsed interference Two 200 MSPS, 10 bit ADC’s: can sample either a 100 MHz channel or 2 pols at 50 MHz each, real-time “asynchronous pulse blanking” (APB) algorithm Su 05 Canton campaign results Courtesy: J. Johnson, Ohio State 27Piepmeier - COSPAR, Montreal

Agile Digital Detector - University of Michigan ADD Specifications and Performance Direct sampling digitizer of V-pol and H-pol 1413 MHz radiometer RF signals (no LO required) Flight qualified FPGA processor – complex correlator forms 3 rd and 4 th Stokes TBs –2 nd moment provides fully polarimetric TB –2 nd and 4 th central moment provides kurtosis –16 frequency subbands over full 24 MHz radiometer passband permits frequency domain RFI mitigation –Nyquist+ oversampling (x600) permits time domain RFI mitigation Aircraft prototype ADD and automated C&DH for scientific demonstrations in a relevant environment Flight line for Texas WB- 57 demonstration flight Images of TB (left) and kurtosis (right) at Galveston coastal crossing during demo flight. Kurtosis responds only to non-thermal signals. ADD spaceflight prototype brassboard. Analog signal RF and clock inputs at right. 28Piepmeier - COSPAR, Montreal

Soil Moisture-Active/Passive July 14, 2008 Piepmeier - COSPAR, Montreal 29 NASA’s first Decadal Survey Mission Launched scheduled for 2013 L-band microwave radiometer and SAR

Regulatory Approach - EESS July 14, 2008 Piepmeier - COSPAR, Montreal 30

RAS Regulatory Framework July 14, 2008 Piepmeier - COSPAR, Montreal 31

EESS and RAS - Common Organizations July 14, 2008 Piepmeier - COSPAR, Montreal 32

Closing Thoughts EESS and RAS have differences (up vs. down, global vs. local) EESS and RAS have similarities (broad spectrum usage, need for spectrum outside of allocations) Collaboration possibilities exist –Spectrum surveys –EESS must put RAS technologies into space –WRC-11 agenda item for f>275 GHz Solution space –Regulatory –Technological July 14, 2008 Piepmeier - COSPAR, Montreal 33