Space experiment on the International Space Station with P-band SAR Space experiment on the International Space Station with P-band SAR B.Kutuza, A.Kalinkevitch, A.Zahkarov - B.Kutuza, A.Kalinkevitch, A.Zahkarov - Kotel’nikov IRE RAS, Kotel’nikov IRE RAS, V.Stasevich, A.Zimov - NPP “ROBIS”, V.Stasevich, A.Zimov - NPP “ROBIS”, Yu.Smirnov - RSC “ENERGY”, Russia Yu.Smirnov - RSC “ENERGY”, Russia

Overview Introduction and motivation Airborne SAR experiments Principles of building the P-band SAR on ISS Antenna and power characteristics Expected results

Motivation Severe reduction of forest biomass, affecting the carbon balance Change of sea waters movement direction (Gulf stream, Kuroshio) Considerable reduction of water storage in Earth glaciers Acute pollution of particular inland water reservoirs (Black Sea, Caspian Sea, Azov Sea, Baikal).

Key problems Propagation effects in ionosphere (Ionosphere affects the phase and orientation of polarization plane of electromagnetic waves in P-band) Design of large SAR antenna SAR external calibration

Airborne Experiments Location of the Antennas on the Plane

Main Features of the IMARC SAR Complex ParameterValue FrequencyXLPVHF Wavelength, cm PolarizationVV, HH, VH, HV Resolution, m Antennas: gain, dB Width in azimuth, deg Width in elevation, deg24 60

Images Obtained by IMARC SAR System L-bandP-bandVHF-band Spas-Klepiki, Ryazanskaya Region

Forest Sensing Radar and photo images of different forest cover types at X (HH-polarization), P (VV- polarization) and VHF (HH- polarization) bands

Sea Sensing Radar images of “Chesh inlet” of the Barentz Sea and part of the sea shore obtained simultaneously at 4- cm (VV), 68-cm (VV) and 2.5 m (VV) wavebands The images show: 1) low salinity zones 2) wave structures 3) vortex near the Suvoy rock 4) Peshy-river estuary

Location of P-band SAR antenna on the ISS.

Direction of antenna beam relative to ISS flight direction

Antenna characteristics Mirror antenna with 32 Antenna efficiency is 0,5 Antenna gain is 25 dB

Power characteristics Transmitted radar impulse power is 50 W Chirp impulse duration is 25 Doppler frequency band is 2,4 kHz Receiver noise temperature T P = 500  K

SAR characteristics Orbit inclination 51.7 deg Ground range resolution is about 50 m Observation angle Radar swath on the ground is km Noise equivalent normalized radar cross-section is -30dB

Objects and regions Forests and open soil regions of Buryatia, Mari El Republic, Krasnoyarsk Kray, Meshchera (Russia) Forests of equatorial Africa and South America Sea and sea ice of Okhotsk at various times of a year Mountain glaciers of Caucasus, Altai, Alps, Himalayas, including those under snow cover Water stratification in the areas of large sea currents, first of all Kuroshio and Gulfstream.

Expected results In this space experiment we plan to work out : Methodical questions of measurements, digital processing and interpretation of backscattered signals acquired by means of spaceborne P-band SAR Estimation of actual level of geometric and polarization distortions arising due to the ionosphere effects Studying the possibility of natural objects (sea, forest, ice, soil) parameters estimation