AIRSAR Summary

AIRSAR Airborne Synthetic Aperture Radar

AIRSAR was an all-weather imaging tool able to penetrate through clouds and collect data at night. The longer wavelengths could also penetrate into the forest canopy and in extremely dry areas, through thin sand cover and dry snow pack.

AIRSAR served as a NASA radar technology testbed for demonstrating new radar technology and acquiring data for the development of radar processing techniques and applications.

AIRSAR Technical Specs

	P Band	L Band	C Band
Frequency/wavelength	0.45GHz/67cm	1.26 GHZ/23cm	5.31GHz/5.7cm
Polarization	Full	Full	Full
Range Resolution	7.5m	3.75m	1.875m
Swath Width (nominal)	10km	10km	10km
Off-Nadir Angle (normal)	20-60°	20-60°	20-60°

Read more on the AIRSAR website.

AIRSAR Data

AIRSAR data are considered unrestricted and are freely available from the SDC. AIRSAR data are available for immediate download using the URSA interface.

AIRSAR data was collected using the following modes:

• POLSAR Mode: Fully polarimetric data are acquired at all three frequencies in P-, L-, C-band for 40 Mhz or 20 Mhz. The L-band also provides 80 MHz bandwidth data.
• TOPSAR Mode: In TOPSAR mode, AIRSAR collects interferometric data using C- and L-band vertically-displaced antenna pairs to produce digital elevation models (DEM's). The radars which are not being used for interferometry (P-band for XTI2 or P-band and L-band for XTI1) collect quad-pol data co-registered with the C-band DEM. Interferometric data can be collected in "ping-pong" mode, where each antenna is used alternately for transmit and the effective baseline is doubled, and in "common-transmitter" mode where only one antenna is used for transmit.
• ATI Mode: Data collected in the along-track interferometry (ATI) mode can be used to measure ocean current velocities. Two pairs of antennas, one C-band and one L-band, separated along the body of the plane, are used to collect ATI data.

More detailed product descriptions are available from the AIRSAR website

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ERS-1 SAR Summary

ERS-1 Synthetic Aperture Radar

In image mode the SAR provides high resolution two-dimensional images with a spatial resolution of 26 m in range (across track) and between 6 and 30 m in azimuth (along track). Image data is acquired for a maximum duration of approximately ten minutes per orbit.

ERS-1 SAR Technical Specs

	Standard Mode
Frequency/wavelength	5.3GHz/C-band 5.6cm
Polarization	VV
Spatial Resolution	30m
Swath Width	100km
Off-Nadir Angle	21°

Read more on the ESA website.

ERS-1 SAR Data

Archived ERS-1 SAR data are available from the ASF SAR Data center for the regions covered by the ASF STGS station mask and the McMurdo station mask. Anyone may search the SDC archive using the URSA interface. However, ERS-1 data are considered restricted data and a short proposal is required to receive the data.

ERS-1 data are available at three different processing levels.

• Level Zero: Raw signal data that requires SAR processing before it can be visualized. Data can be received as a swath product in SKY telemetry format or subdivided into frames with an accompanying CEOS format leader file.
• Single Look Complex (SLC): Processed SAR data that contains both amplitude and phase information. The data is not multilooked and to be visualized must be further processed to an amplitude image.
• Detected Image: Fully processed SAR data which only contains the amplitude information. Image does not require any further SAR processing to be visualized.

Satellite:ERS-1

ERS-2 SAR Summary

ERS-2 Synthetic Aperture Radar

In image mode the SAR provides high resolution two-dimensional images with a spatial resolution of 26 m in range (across track) and between 6 and 30 m in azimuth (along track). Image data is acquired for a maximum duration of approximately ten minutes per orbit.

ERS-2 SAR Technical Specs

	Standard Mode
Frequency/wavelength	5.3GHz/C-band 5.6cm
Polarization	VV
Spatial Resolution	30m
Swath Width	100km
Off-Nadir Angle	21°

Read more on the ESA website.

ERS-2 SAR Data

Archived ERS-2 SAR data are available from the ASF SAR Data center for the regions covered by the ASF STGS station mask and the McMurdo station mask. Anyone may search the SDC archive using the URSA interface. However, ERS-2 data are considered restricted data and a short proposal is required to receive the data.

ERS-2 data are available at three different processing levels.

• Level Zero: Raw signal data that requires SAR processing before it can be visualized. Data can be received as a swath product in SKY telemetry format or subdivided into frames with an accompanying CEOS format leader file.
• Single Look Complex (SLC): Processed SAR data that contains both amplitude and phase information. The data is not multilooked and to be visualized must be further processed to an amplitude image.
• Detected Image: Fully processed SAR data which only contains the amplitude information. Image does not require any further SAR processing to be visualized.

Satellite:ERS-2

JERS-1 SAR Summary

JERS-1 Synthetic Aperture Radar

The JERS-1 SAR is a high-resolution, all-weather imaging radar that can map the topography and geological characteristics of the earth's surface.

JERS-1 SAR Technical Specs

	Standard Mode
Frequency	1.3GHz L-band
Polarization	HH
Spatial Resolution	18m
Swath Width	75km
Off-Nadir Angle	35°

JERS-1 SAR Data

Archived JERS-1 SAR data are available from the ASF SAR Data and coverage is global. Anyone may search the SDC archive using the URSA interface. However, JERS-1 data are considered restricted data and a short proposal is required to receive the data.

JERS-1 data are available at three different processing levels.

• Level Zero: Raw signal data that requires SAR processing before it can be visualized. Data can be received as a swath product in SKY telemetry format or subdivided into frames with an accompanying CEOS format leader file.
• Single Look Complex (SLC): Processed SAR data that contains both amplitude and phase information. The data is not multilooked and to be visualized must be further processed to an amplitude image.
• Detected Image: Fully processed SAR data which only contains the amplitude information. Image does not require any further SAR processing to be visualized.

Satellite:JERS-1

PALSAR Summary

PALSAR Phased Array L-band Synthetic Aperture Radar

PALSAR is an L-band SAR capable of detailed, all-weather, day-and-night observation, and repeat-pass interferometry. PALSAR has multiple observation modes with variable polarization, resolution, swath width, and off-nadir angles.

PALSAR Technical Specs

	Fine Resolution		ScanSAR	Polarimetric
Center Frequency	L-Band (1.27 GHz)
Polarization	HH or W	HH+HV or VV+VH	HH or VV	HH+HV+VV+VH
Spatial Resolution	10m	20m	100m	30m
Swath Width	70km	70km	250-350km	30km
Off-Nadir Angle	37-47° (default)		20-49° (default)	20-49° (default)

PALSAR cannot observe the areas beyond 87.8 degrees north latitude and 75.9 degrees south latitude when the off-nadir angle is 41.5 degrees.

Read more on the JAXA website.

PALSAR Data

ALOS PALSAR data are available from the SDC for US researchers with an approved ALOS PALSAR Proposal. ALOS PALSAR data at the SDC is focused on North, South, and Central America but global data are available.

PALSAR data are available as:

• Level 1.0: Reconstructed, unprocessed signal data with radiometric- and geometric-correction coefficients appended but not applied.
• Level 1.1: Single Look Complex products provided in slant range geometry and compressed in range and azimuth. Individual files are provided for each polarization for multi-polarization modes.
• Level 1.5: Multi-look processed images projected onto map coordinates. Data can be processed either geo-referenced or geo-coded. Individual files are provided for each polarization for multi-polarization modes.

PALSAR data are provided in CEOS format. More detailed product descriptions are available from the JAXA website.

PALSAR Processing Information

The SDC uses the JAXA processor for processing of ALOS PALSAR, which is periodically updated. PALSAR processor versions employed by the SDC can be viewed here.

RADARSAT-1 SAR Summary

RADARSAT-1 Synthetic Aperture Radar

RADARSAT-1 is equipped with an advanced radar sensor, the synthetic aperture radar (SAR). It is a powerful microwave instrument. It transmits and receives signals for capturing high quality images of the Earth night and day and in all weather conditions. As an active sensor, RADARSAT-1's SAR transmits a microwave energy pulse (C-band at 5.3 GHz frequency) to the Earth, and the SAR measures the amount of energy that is reflected back to the satellite from the Earth's surface.

The RADARSAT-1 SAR instrument can shape and steer its radar beam using C-band. A wide variety of beam widths are available to capture swaths of 45 to 500 kilometers, with a range of 8 to 100 meters in resolution and incidence angles of 10 to 60 degrees.

RADARSAT-1 Technical Specs

	Fine Mode	Standard Mode	ScanSAR Mode
Frequency/wavelength	5.3GHz/C-band 5.6cm
Polarization	HH	HH	HH
Spatial Resolution	8m	30m	50-100m
Swath Width	45km	100km	300-500km
Off-Nadir Angle	37-47°	20-49°	20-49°

Read more on the CSA website.

RADARSAT-1 Data

RADARSAT-1 data at the SDC is global in nature but only includes data acquired prior to May 3, 2008. Anyone may search the SDC archive using the URSA interface for RADARSAT-1 data. However, most RADARSAT-1 data considered restricted and a short proposal is required to access the data.

RADARSAT-1 data are available at three different processing levels.

• Level Zero: Raw signal data that requires SAR processing before it can be visualized. Data can be received as a swath product in SKY telemetry format or subdivided into frames with an accompanying CEOS format leader file.
• Single Look Complex (SLC): Processed SAR data that contains both amplitude and phase information. The data is not multilooked and to be visualized must be further processed to an amplitude image.
• Detected Image: Fully processed SAR data which only contains the amplitude information. Image does not require any further SAR processing to be visualized.

Satellite:RADARSAT-1

UAVSAR Summary

UAVSAR Uninhabited Aerial Vehicle Synthetic Aperture Radar

UAVSAR, a Jet Propulsion Laboratory (JPL)-built reconfigurable, polarimetric L-band synthetic aperture radar (SAR), is specifically designed to acquire airborne repeat track SAR data for differential interferometric measurements.

The radar is designed to be operable on a UAV (Uninhabited Aerial Vehicle), but will initially be demonstrated on a on a NASA Gulfstream III. The radar is fully polarimetric, with a range bandwidth of 80 MHz (2 m range resolution), and a range swath greater than 16 km.

More information is available at the JPL UAVSAR Website.

The radar for the UAV platform is a compact pod-mounted polarimetric L-band radar for repeat-pass observations. The system will demonstrate key measurements — both during and after a seismic event — for monitoring volcanic activity and for monitoring anthropogenic induced surface change such as subsidence induced by oil or water withdrawal, or other displacements of the surface from tunneling activities.

Key Radar Instrument Parameters

Frequency	L-band
Polarization	Full
Resolution (range)	1.8m
Swath Width	16km

Read more on the JPL UAVSAR Website.

UAVSAR Data

UAVSAR data are processed at JPL and are freely available from the SDC. UAVSAR data are available for immediate download using the URSA interface.

UAVSAR data are provided as Polarimetric Products and Interferometric Products.

Polarimetric Products

• SLC files (.slc): Calibrated single look complex files for each polarization (HH, HV, VH, and VV), floating point format, little endian, 8 bytes per pixel, corresponding to the scattering matrix.
• MLC files (.mlc): Calibrated multi-looked cross products, floating point format, three files 8 bytes per pixel, three files 4 bytes per pixel, little endian.
• Compressed Stokes Matrix product (.dat): AIRSAR compressed stokes matrix format for software compatibility (http://airsar.jpl.nasa.gov/data/data_format.pdf). 10 bytes per pixel.
• Ground projected files (.grd): calibrated complex cross products projected to the ground in simple geographic coordinates (latitude, longitude). There is a fixed number of looks for each pixel. Floating point, little endian, 8 or 4 bytes per pixel.
• Hgt file: the DEM that the imagery was projected to, in the same geographic coordinates as the ground projected files. Floating point (4 bytes per pixel), little endian, ground elevation in meters.
• Annotation file (.ann) : a text file with metadata.

Interferometric Products

• SLC files (.slc): Calibrated single look complex files for each flight track (track 1, T1; and track 2, T2), floating point format, little endian, 8 bytes per pixel, corresponding to the same element of the scattering matrix. These files are available by request, but are not normally included in the data distribution.
• AMP files (.amp1 and .amp2): Calibrated multi-looked amplitude products, one file per repeat track, floating point format 4 bytes per pixel, little endian.
• INT files (.int): interferogram product, one file per pair of repeat tracks, complex floating point format 8 bytes per pixel, little endian.
• UNW files (.unw): unwrapped interferometric phase product, one file per pair of repeat tracks, floating point format 4 bytes per pixel, little endian.
• COR files (.cor): interferometric correlation product, one file per pair of repeat tracks, floating point format 4 bytes per pixel, little endian.
• GRD files (.grd): interferometric products projected to the ground in simple geographic coordinates (latitude, longitude). There is a fixed number of looks for each pixel. Floating point or complex floating point, little endian, 8 or 4 bytes per pixel.
• HGT file: the DEM that the imagery was projected to, in the same geographic coordinates as the ground projected files. Floating point (4 bytes per pixel), little endian, ground elevation in meters.
• KML and KMZ files (.kml or .kmz) : These files allow you to view a representation of their corresponding file type in Google Earth or similar software.
• PNG files (.png) : These are representations of the corresponding products in standard PNG Format.
• ANN file (.ann) : A text annotation file with metadata.

Complete product descriptions are available from the JPL UAVSAR Website

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