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1540.pdf

  1. 1. PROTO-FLIGHT TEST OFTHE DUAL-FREQUENCY PRECIPITATIONRADAR FOR THE GLOBALPRECIPITATION MEASUREMENTKinji FURUKAWA 1), Masahiro KOJIMA 1), Takeshi MIURA 1),Yasutoshi HYAKUSOKU 1),Toshio IGUCHI 2), Hiroshi HANADO 2), Katsuhiro NAKAGAWA 2),and Minoru OKUMURA 3)1) GPM/DPR Project Team, Japan Aerospace Exploration Agency2) Applied Electromagnetic Research Institute, National Instituteof Information and Communications Technology3) NEC TOSHIBA Space systems, Ltd. IGARSS2011
  2. 2. Contents Overview of Global Precipitation Measurement Overview of Dual-frequency Precipitation Radar Development status of DPR Schedule Conclusion IGARSS2011 P2
  3. 3. Overview of Global Precipitation Measurement IGARSS2011 P3
  4. 4. Objective and Mission Requirements of GPM Main objective To establish accurate and frequent global precipitation observing system from the space Basic Mission Requirements of GPM Global observation of precipitation Accurate precipitation measurement Frequent precipitation measurement IGARSS2011 P4
  5. 5. Concept of GPMGPM = follow-on mission of the Tropical Rainfall Measuring Mission (TRMM)Core Observatory• Dual-frequency Precipitation Constellation Satellites Radar (DPR) • Microwave Radio-meters• Microwave Imager (GMI) installed on each satellite Frequent precipitation Highly sensitive precipitation measurement measurement Calibration for constellation Expected Partners: radiometers NASA, NOAA, CNES-ISRO, China, others 2 satellites JAXA and NICT: DPR and H2A Launcher NASA : Spacecraft bus and GMI 3-hourly global 8 satellites rainfall map Blue: Inclination ~65º (GPM core) Green: Inclination ~35º (TRMM) IGARSS2011 P5
  6. 6. Overview of GPM Core Observatory GPM Core ObservatoryDual-frequency precipitation radar GMI(DPR) consists of Flight direction DPR 407 km altitude,Ku-band (13.6GHz) radar : KuPR 65 deg inclination and Non-sun-synchronous circular orbitKa-band (35.55GHz) radar : KaPR Range resolution = 250m and 500m KaPR GMI KuPR Swath: 125 km Swath: 245 km Swath: 800km 5km IGARSS2011 P6
  7. 7. Overview of Dual-frequency Precipitation Radar IGARSS2011 P7
  8. 8. Objectives of DPR Three-dimensional observation of precipitation High sensitivity measurement of light rainfall and heavy snowfall in high latitude Accurate estimation of rainfall rate by combining the Ku- and Ka-band radar data. Improvement of MWR’s precipitation estimation accuracy using the precipitation parameters (DSD, melting level, rain type, storm height, etc.) estimated by using DPR data. IGARSS2011 P8
  9. 9. Main Characteristics KuPR KaPR Frequency 13.597 , 13.603 GHz 35.547 , 35.553 GHz Range Resolution 250 m 250 m / 500 m Horizontal Resolution 5.2 km (at nadir) 5.2 km (at nadir) Swath Width 245 km 125 km Minimum Detectable Rainfall Rate 0.5mm/h 0.2mm/h Beam-matching Accuracy < 1000 m Observation altitude Up to 19 km Up to 19 km - 5 dB below system noise - 5 dB below system noise level Dynamic Range level + 5 dB over surface echo level + 5 dB over surface echo level Measurement Accuracy within ± 1 dB within ± 1dB Data Rate < 108.5kbps < 81.5kbps Mass < 472 kg < 336kg Power Consumption < 446 W orbit average < 344 W orbit average Size 2.5 × 2.4 × 0.6 m 1.4 × 1.2 × 0.8 m IGARSS2011 P9
  10. 10. Outlook of KuPR and KaPRKuPR KaPR 2.4m 2.5m 1 .4 m 1.2m 0.6m 0.8m 約400kg 約300 kg IGARSS2011 P10
  11. 11. KuPR system block diagram x8128 ANT x16 IGARSS2011 P11
  12. 12. KaPR system block diagram IGARSS2011 P12
  13. 13. Precipitation Measurement by DPR Detectable range of KaPR (35.55 GHz) Matched beam of KuPR and KaPR Detectable range of KuPR (13.6GHz) Height ICE Sensitive observation by the KaPR SNOWSnowfall Discrimination of snow andmeasurements in rain using differentialthe frigid zones MELTING KuPR attenuation method LAYAR KaPR RAIN Accurate rainfall estimation using differential attenuation method (DSD parameter estimation) Accurate rainfall measurements in the tropics and the temperate zones Radar reflectivity IGARSS2011 P13
  14. 14. Scanning Method KuPR footprint : Dz=250m KaPR footprint (Matched with KuPR) : Dz=250m KaPR footprint (Interlaced) : Dz=500m 49 26 3725 49 13 1 25 1 KaPR: 125km (25+24beams) KuPR: 245km (49beams) The synchronized In the interlacing scan area ( ), the matched beam ( ) is KaPR can measure snow and light necessary for the dual- rain in a high-sensitivity mode with a frequency algorithm. double pulse width. IGARSS2011 P14
  15. 15. Beam Matching Both radars should have the same foot print locations (requires good alignment and synchronization between KuPR & KaPR)For post-launch checkout; Active radar calibrator (ARC) experiment will be donefrom ground to estimate the beam mismatch.To match the beams in; Cross-track direction : control the phase shifters ARC Scan direction Along-track direction : set delay of pulse transmitting timing for one radar system. IGARSS2011 P15
  16. 16. Variable Pulse Repetition Frequency VPRF is to change the transmitting and receiving pulse interval according to the distance to a target. Beam swings Satellite altitude TRMM PR Fixed Fixed DPR (KuPR, KaPR) Variable Variable Purpose Efficient sampling for higher sensitivity To deal with more altitude variation, compared with TRMM Method Use different timing for transmitting (Tx) pulses and receiving (Rx) pulses. Tx Tx Tx Rx Time Earth Time orbit target (rain) Range Range IGARSS2011 P16
  17. 17. Development status of DPR IGARSS2011 P17
  18. 18. Proto-flight Test Flow of DPR KuPR Mass EPT Acoustic Vibration TBT/TVT EMC EPTPropertyNov. 2010 EPT: Electric Performance Test KuPR/KaPR TBT: Thermal Balance Test Co-operation TVT: Thermal Vacuum Test KaPR Mass EPT Acoustic Vibration EMC TBT/TVT EPT Property Dec. 2010 March 11, 2011 Japan Earthquake Occurred. IGARSS2011 P18
  19. 19. Test ConfigurationsKuPR Electrical Performance Test Vibration test TBT/TVTKaPR Acoustic TestElectrical Performance Test (Covers are attached in this picture. They are removed during test) IGARSS2011 ISTS2011 P19
  20. 20. Example of PFT data (1/2) KuPR Initial Electrical Performance Test TX Antenna Pattern - Nadir IGARSS2011 P20
  21. 21. Example of PFT data (2/2) External Calibration Scan Pattern Max hold measurement, including 17 beams for external calibration IGARSS2011 P21
  22. 22. Recovery Activities on DPR Inspection KuPR is contaminated by the particles of the wall material (plasterboard) . Cleaning Vacuum cleaner, Low adhesive tape, wiping Health Check Power consumption, Receiving characteristic, Transmitting characteristic, SSPA LNA current Hold the PFT re-start review on May 19. Re-start PFT. IGARSS2011 P22
  23. 23. Current Status KuPR/KaPR co-operation test was completed. This test is intend to verify the following items. Co-operation by using one SCDP No interference between KuPR and KaPR Confirmation of the commanding based on the operation scenario. Relative location between KuPR and KaPR during co-operation test simulates actual location on GPM core observatory. Flight harnesses connecting KuPR and KaPR are used. KaPR TBT/TVT is on going IGARSS2011 P23
  24. 24. Schedule KuPR Mass EPT Acoustic Vibration TBT/TVT EMC EPT Property Nov. 2010 EPT: Electric Performance Test KuPR/KaPR TBT: Thermal Balance Test Co-operation TVT: Thermal Vacuum Test KaPR Mass EPT Acoustic Vibration EMC TBT/TVT EPT Property Dec. 2010 Change the test order March 11, 2011 Japan Earthquake Occurred. KuPR EMC EPT KuPR/KaPRRe-start Co-operationMay 20, 2011 EMC TBT/TVT EPT KaPR NOW IGARSS2011 P24
  25. 25. Conclusion The DPR that will be installed on the GPM core observatory is being developed by JAXA and NICT. The main objective of the DPR is to measure the three- dimensional structure of precipitation including light rainfall and snowfall. Though Proto-flight test was interrupted due to Japan Earthquake on March 11, 2011, there is no significant impact to DPR from technical and schedule point of view. Proto-flight test has been restarted, and will be completed in the near future. After completion of all PFT, the DPR instrument will be verified as a space borne radar. IGARSS2011 P25

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