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Jean PLA CNES, Toulouse, France Frequency manager

THE RESULTS OF WRC-2007 Earth Exploration Satellite PASSIVE Earth Exploration Satellite ACTIVE ILLUSTRATION of the usage of some passive frequency bands through a concrete example. Jean PLA CNES, Toulouse, France Frequency manager. Objective of the passive bands (WRC-07).

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Jean PLA CNES, Toulouse, France Frequency manager

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  1. THE RESULTS OF WRC-2007Earth Exploration Satellite PASSIVE Earth Exploration Satellite ACTIVE ILLUSTRATION of the usage of some passive frequency bands through a concrete example Jean PLA CNES, Toulouse, France Frequency manager

  2. Objective of the passive bands (WRC-07) 1400-1427 MHz: salinity (ocean), soil moisture (ground) 10.6-10.7 MHz: rain, snow, ice, sea state, ocean wind 23.6-24 GHz: total content of water vapour 31.3-31.5 GHz: the lowest cumulated effects due to oxygen and water vapour in the vicinity of the 50 GHz band. Optimum window channel to see the Earth’s surface: reference for the other channels. 36-37 GHz: cloud liquid water, vegetation structure, surface roughness 50.2-50.4 GHz: temperature profile

  3. Agenda items 1.2, 1.20 and 1.3 of WRC-07 • PASSIVE BANDS • Agenda Item 1.2: SHARING ISSUE Establish sharing conditions between passive and active services within the bands 10.6-10.68 and 36-37 GHz • Agenda Item 1.20: UNWANTED EMISSIONS ISSUE Protection of passive sensors from unwanted emissions within purely passive bands (5.340: all emissions are prohibited) • ACTIVE BANDS Agenda Item 1.3: Considers an extension of 200 MHz to existing active sensing allocation from 9500 to 9800 MHz.

  4. Agenda item 1.2 of WRC-07 • Considers sharing conditions between FS/MS and passive sensors in the bands 10.6-10.68 GHz and 36-37 GHz • Band 10.6-10.68 GHz shared between • FS & MS: active services • EESS (passive), SRS (passive), Radio Astronomy • Note: the band 10.68 to 10.7 GHz is purely passive (5.340) • Band 36-37 GHz shared between • FS & MS: active services • EESS (passive), SRS (passive) • One proposed method in the Conference preparatory text: development of sharing criteria based on single entry emission limits to be included in a footnote of Article 5 of the Radio Regulations.

  5. Agenda item 1.20 of WRC-07 Agenda Item 1.20: Considers the results of studies, and proposals for regulatory measures regarding the protection of passive sensors from unwanted/out-of-band emissions of active services falling within some specified passive bands (i.e.,1400-1427 MHz, 23.6-24 GHz, 31.3-31.5 GHz, 50.2-50.4 GHz and 52.6-54.25 GHz) One proposed method in the Conference preparatory text: development of a single entry emission limit for each corresponding active service within the EESS (passive) band to be included in a footnote of Article 5 of the Radio Regulations.

  6. Unwanted emissionsDomain Out Of Band domain Spurious domain Active band Passive band EESS(passive)AI 1.20 Agenda item 1.20 of WRC-07: definitions frequency

  7. Agenda item 1.20 of WRC-07: unwanted emission problem, list of band pairs • Protection of EESS in the band 31.3-31.5 GHz vis-à-vis FS for the 31-31.3 GHz band (WRC03: -38dBW/100MHz)) in regions 2 and 3 • Protection of EESS in the band 52.6-54.25 GHz vis-à-vis FS for the 51.4-52.6 GHz band (WRC03: -33dBW/100MHz)) in regions 2 et 3

  8. Agenda items 1.2 and 1.20 of WRC-07: decision of the Conference • Recommended levels for the following services and frequency bands • For the protection of the exclusive passive bands (footnote 5.340)1400-1427 MHz (applicable to all active services around 1.4 GHz) and 31.3-31.5 GHz (for FSS in the 30-31 GHz band) • The FS and MS services operating within the band 10.6-10.68 GHz • Mandatory limits for the following services and frequency bands • For FS and MS services operating within the band 36-37 GHz • For the protection of the following exclusive passive frequency bands (5.340): 23.6-24 GHz (ISS below 22.55 GHz), 31.3-31.5 GHz (FS at 31-31.3 GHz), 50.2-50.4 GHz (for FSS below 50.2 and above 50.4 GHz) and 52.6-54.25 GHz (for FS below 52.6 GHz)

  9. Agenda item 1.3 of WRC-07 OBJECTIVE OF THE ACTIVE BAND AT 8 GHz Synthetic aperture radars (SARs) are used in space to typically produce radar image maps of the terrain below as the spacecraft motion creates a synthetic aperture. In order to satisfy global environmental monitoring requirements for improved resolution, EESS (active) and the SRS (active) allocations require an increase of 200 MHz at 8 GHz. This additional bandwidth will greatly improve the resolution of the features for global monitoring and for environmental and land-use purposes ( water and polar ice caps conditions, among others), increase versatility in emergency mitigation and disaster protection

  10. Agenda item 1.3 of WRC-07: extension of EESS allocation Radio Regulations 9 500 9 800 300 MHz 200 MHz: primary status 100 MHz: secondary status 9 300 9 500 9 800 9 900 10 000 WRC-07 Decision 200 MHz 100 MHz 9 300 9 900 EESS and SRS Restriction to 600 MHz EESS-instruments only

  11. Illustration of the usage of some frequency passive bands: example of the MEGHA-TROPIQUES satellite (CNES-ISRO) • Study the water and energy cycle in the tropics associated to convection: • retrieval of rain, radiative budget and water vapor • application to: • Model data assimilation to improve weather forecast • General circulation models validation/improvement • Climate model validation/improvement • Risk assessment/management (floods, hurricanes) • 3 instruments: • MADRAS rain/cloud estimates 19 to 157 GHz • ScaraB radiative budget long wave/short wave VIS-IR • SAPHIR water vapor sounding 183 GHz

  12. Illustration of the usage of some frequency passive bands: example of the MEGHA-TROPIQUES satellite (CNES-ISRO): Mission features • Coverage 23°N to 23°S • Repetition time from 3 to 6 times per day􀃆 • Tropical Orbit (20° inclination) • High altitude = 865km􀃆 • Wide swath Allowing the Study of Mesoscale Convective Systems> 100 km

  13. MADRAS instrument on board the MEGHA-TROPIQUES satellite (CNES-ISRO) • The MADRAS instrument is a 9 channels self-calibrating microwave imager. It is the main instrument of the MEGHA-TROPIQUES mission, jointly managed by the CNES and ISRO agencies. • MADRAS is a conical scanning radiometer (rotation speed is around 25 rpm) The microwave radiation from the scene is collected by the antenna reflector and focused to the respective horns. The scene is scanned by rotation of the complete antenna i.e. the reflector and the horns. Every rotation, the angular sector where the antenna beam looks at the platform is used to calibrate the receivers • MADRAS has operating frequencies in the range 18.7 GHz-157 GHz • 18.7 GHz: rain above oceans • 23.8 GHz: integrated water vapour • 36.5 GHz: liquid water in clouds, rain above sea • 89 GHz: convective rain areas over land and sea • 157 GHz: ice detection in clouds

  14. Illustration of the usage of some frequency passive bands: MADRAS instrument, rain retrieval • Rain retrieval over Ocean is easier because all channels are useful • Rain retrieval over Land is difficult because only higher frequencies are useful, specially 89 GHz. • Tropical rain is VERY constrained by ice microphysics hence higher channels • 157 GHz is innovative and VERY promising for rain over land

  15. 2300 km 1700 km SAPHIR ScaRaB MADRAS Schematic representation of the swath of the 3 instruments on board MEGHA-TROPIQUES

  16. MADRAS instrument: usage of the frequencies The measurement of the precipitation rate and of the characteristics of the clouds is the main objective of the MADRAS microwave imager. The highest frequencies (89 and 157 GHz) are sensitive to ice particles at the top of the clouds, providing a location of the convective rain areas, over land and sea. Channels at lower frequencies are useful over the ocean: • measure of the liquid water and precipitations using the absorption at 10.6 - 18,7 and 36,5 GHz • measure of the vapour water content at 24 GHz • estimation of the wind at the surface of the sea at 10.6 et 18,7 GHz.

  17. 310 K 100 K Sensitivity of different instrument frequencies to Tropical Cyclone Rain 8 km 85 GHz 4 km 19-37 GHz 2 km 10 GHz TRMM - 33151 0 Rain Rate 50 mm/h

  18. Illustration of the usage of some frequency passive bands: simulation of the usage of MADRAS measurements on a real cyclone • Simulated MADRAS data from TRMM-Precipitation Radar (real swath will be much broader) • Hurricane Dean observed during in August 2007 in the Carribean • Rain is hot (emission) over cold background at 19 GHz • Ice precipitation are cold (scattering) over hot background at 89 and 157GHz

  19. CONCLUSION 1: LEVELS AND LIMITS IN THE RR • The mandatory limits for most of the bands above 20 GHz in the Radio Regulation provide a long term protection of the passive bands. • The recommended levels for the bands below 20 GHz represent a clear signal to Administrations for a better protection, in particular for the passive band 1400-1427 MHz band which is unique for soil moisture and sea salinity. In 2008, a joint ESA-CNES mission called SMOSwill be launched next year.

  20. CONCLUSION 2: FUTURE AGENDAS FOR WRC-2011 The relevant agenda items in connection with Remote Sensing are as follows for WRC-2011 1.6: frequencies between 275 and 3000 GHz: passive or active? 1.8: regulatory issues relative to the fixed service between 71 and 238 GHz (protection of the passive band 86-92 GHz) 1.22: effect from Short Range Devices (SRD), impact on ALL radiocommunication services

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