SIR-C
type: Concept
definition: The Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) was flown as part of the Space Radar Laboratory-1 payload launched on the Space Shuttle STS-59 on April 9, 1994. The objectives of the Spaceborne Imaging Radar-C (SIR-C) instrument were to investigate characteristics of the Earth's surface such as (1) vegetation extent and biomass condition, (2) soil moisture and snow properties, (3) recent climate change and tectonic activity, and (4) ocean wave spectra. The SIR-C was jointly operated from the Space Shuttle with the X-band Synthetic Aperture Radar (X-SAR), provided by the German Space Agency (DARA)/German Aerospace Research Establishment (DLR) and the Italian Space Agency (ASI), on the same Space Radar Laboratory (SRL) platform. The SIR-C radar operated at L-band (24-cm wavelength or 1250 MHz) and C-band (5.6-cm wavelength or 5300 MHz) in multiple polarization modes (HH,HV,VH,VV). The antenna was composed of two planar arrays, one for L-band and one for C-band, in dual-polarized operation. Each array was composed of a uniform grid of dual-polarized microstrip antenna radiators. The SIR-C antenna was 12.2 meters, weighed over 10,500 kg and filled the Shuttle cargo bay. SIR-C provided images of the magnitudes of HH,VV,and cross-polarized returns, images of the relative phase difference between multiple polarization returns, and derivation of linear, circular, or elliptical polarization. Image resolution was 25 m (20 MHz bandwidth) and 40 m (10 MHz bandwidth). The swath width ranged from 15 to 65 km for calibrated images and 40 to 90 km for mapping mode (SCANSAR) images. In SCANSAR mode, the antenna was steered electronically or mechanically to acquire data at various incidence angles (15 to 55 degrees) increasing the swath width at reduced resolution. Data was acquired at 8 bits per sample or 4 bits per sample in 16 primary modes. SIR-C used four solid state receivers, two each for C-band and L-band. The SIR-C data was recorded on-board on t…
in scheme: instruments

Imaging Radars
type: Concept