Space experiment on the International Space

Station with P-band SAR

B.Kutuza, A.Kalinkevitch, A.Zahkarov - Kotel’nikov IRE RAS, V.Stasevich, A.Zimov - NPP “ROBIS”, 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 ExperimentsLocation of the Antennas on the Plane

Main Features of the IMARC SAR Complex

Parameter Value

Frequency X L P VHF

Wavelength, cm 3.9 23 68 254

Polarization VV, HH, VH, HV

Resolution, m 4-6 8-10 10-15 15-20

Antennas: gain, dB 30 14-17

14-17 9-11

Width in azimuth, deg 18 24 24 40

Width in elevation, deg 24 24 24 60

Images Obtained by IMARC SAR System

L-band

P-band

VHF-band

Spas-Klepiki, Ryazanskaya Region

Forest Sensing

Radar and photo images of different forest cover types atX (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 zones2) wave structures3) vortex near the Suvoy rock4) 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

2m

Power characteristics

Transmitted radar impulse power is 50 W

Chirp impulse duration is 25

Doppler frequency band is 2,4 kHz

Receiver noise temperature TP = 500K

s

SAR characteristics

Orbit inclination 51.7 deg

Ground range resolution is about 50 m

Observation angle

Radar swath on the ground is 40-60 km

Noise equivalent normalized radar cross-section is -30dB

0 010 35

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