Get SAR Data

The following information should help answer the basic questions to get yourself started: How do I get ERS-1, ERS-2, JERS-1, and/or RADARSAT-1 data?

• Data Policies
• Proposal Guidelines
• Find Data
  • URSA
  • Warehouse Inventory Search Tool (WIST)
• Test Data

How do I get ALOS PALSAR data?

• U-PASS Tutorial
• U-PASS
• PALSAR information
• Test Data

I've been approved so whats next?

• Place a DAR [ERS-2 only]
  • DAR Overview
  • URSA
• Order ERS-1, ERS-2, JERS-1, and/or RADARSAT-1 data
  • URSA
  • Warehouse Inventory Search Tool (WIST)
• Order ALOS PALSAR
  • Find data for transfer
  • Order data for processing
  • View PALSAR Data Pool

How do I get my data?

• How to pick up your EDG ftp order

How do I read my ASF data?

• Reading the file name
• Expected data files
• Displaying the data
• Software Tools

How do I...

• Get more data (credits)?

ASF currently has 10 free CD-ROM products available to the public. Most of these products were produced from SAR images found in the ASF archive. The CDs can be ordered through the unrestricted products online order form.

View/Order Products

Level 0 Data

• Get L0 Data via URSA interface
• ERS-1_we.doc.pdf
• ERS-1webdocpart2.pdf
• ERS_CEOS.doc.pdf
• R1L0ref.pdf
• RadarsatXband.pdf
• VX-STF-0.pdf

Level 1 Data

• Get L1 Data via URSA interface
• Order L1 Data Products at EDG

Note: The following are reference pages of numbers and nitty-gritty details. These specifications apply only to data processed since September 1996.

Contents of the leader (".L") file for low-, medium-, or full-resolution images & complex-format products:

• File Descriptor Record (FDR) - 720 Bytes
• Data Set Summary Record - 4096 Bytes
• Map Projection Data Record - 1620 Bytes Note: This data record appears only in RADARSAT ScanSAR Data
• Platform Position Record - 1024 Bytes
• Attitude Data Record - 1024 Bytes
• Radiometric Data Record - 4232 Bytes
• Data Quality Summary Record - 1620 Bytes (Calibrated/Uncalibrated flag at field 79)
• Signal Data Histogram Record - 4628 Bytes
• Processed Data Histogram Record - 4628 Bytes
• Range Spectra Record - 5120 Bytes
• - 1024 Bytes Note: This record appears only in terrain-corrected data.
• Facility Data Record - 1717 Bytes

Specifications for ERS-1, ERS-2, JERS-1, and RADARSAT SAR Data Files Note: the first record of each file contains CEOS formatting information. This record is set to be the same length as a data record. Each subsequent data record also has a 192-byte CEOS prefix. So, you can either strip off the first record and the first 192 bytes off of each subsequent record in order to deal with the data only, or you can read in the entire (data + CEOS formatting) image and ignore the noise around the edge.
View Data Specs ⇒

The goal of the RADARSAT Geophysical Processor System (RGPS) is to derive data sets that will improve our understanding of the role of the Arctic in global climate.

We have available for your perusal, free of charge, finished data products from the entire 97-98 winter and the beginning of the 98-99 winter. Product types available include Backscatter and Ice Thickness (both in one month increments), Deformation, and Lagrangian (these products are continuous, so a stream from january includes data from november and december as well). Additionally, the postscript files from which these data products are created are available in three day increments.

These are available on the Arctic - MEaSUREs site ⇒

In 1997, the Canadian RADARSAT-1 satellite was rotated in orbit, so that its synthetic aperture radar (SAR) antenna looked south towards Antarctica. This permitted the first high-resolution mapping of the entire continent of Antarctica. In less than three weeks, the satellite acquired a complete coverage of radar image swaths as part of the first Antarctic Mapping Mission (AMM-1). Swath images have been assembled into an image mosaic depicting the entire continent at 25 m resolution. The mosaic provides a detailed look at ice sheet morphology, rock outcrops, research infrastructure, the coastline, and other features of Antarctica, as well as representing calibrated radar backscatter data which may provide insight into climate processes affecting the upper few meters of snow cover.

The collection includes images at a wide variety of resolutions, and images from both Versions 1 and 2 of the mosaic, which was updated in 2001 in order to correct a variety of errors.

Learn More & Download RAMP Data ⇒

The AIRSAR dataset has shown its scientific value in numerous research projects. One example is the dataset for Okmok volcano in the Aleutian Islands that was acquired during the AIRSAR PacRim campaign of June 2000. After initial processing at JPL, the AIRSAR data were sent to ASF, where researchers worked with ASF SAR experts to combine numerous strips of data into a mosaic, fuse it to Landsat imagery, check its accuracy, and generate a number of data products. Results included an amplitude image and a high-resolution DEM of Umnak Island. These data were used to produce new geologic maps with excellent spatial accuracy. The previous topographic map of the region was made in 1957 from aerial photographs. Okmok had erupted four times since then, dramatically changing the landscape. The high resolution of the AIRSAR DEM, coupled with the sensitivity to surface roughness of the SAR imagery, provided an unprecedented means to discriminate features such as lava flow contacts, debris avalanche deposits, lahar extents, stream drainage patterns, and coastal features.

Data

At the present time, the accumulated data from past AIRSAR campaigns exists in two locations: 1) The raw data resides with the AIRSAR group at JPL, while 2) the processed data is being held in the Physical Oceanography Distributed Active Archive Center (PO.DAAC). Of the approximately 2 TB of AIRSAR data acquired on thousands of Sony D 1 tapes, 1.25 TB of data products have been processed with the AIRSAR group’s AIRSAR Integrated Processor (AIP). The resulting processed data, metadata, and browse images are stored at the PO.DAAC. Of these data, 850 GB are presently available to the general public in an unrestricted manner, using the Aspera file transfer tool to download the selected data.

Mission

In the mid 1980s, an airborne SAR program was established at JPL by NASA to serve as both a flexible test bed to explore new radar technologies being developed for the shuttle and satellite communities, and to perform SAR data collections in support of the earth science community. The AIRSAR sensor has been flown on a NASA DC 8 passenger jet, modified for research applications and until recently, operated out of Dryden Flight Research Center at Edwards Air Force Base, California. In 1989, the AIRSAR system became operational, providing the three-frequency, fully polarimetric, POLSAR mode, providing data in C band, L band, and P band. Collected data was processed at JPL and delivered to users. This capability provided prototype data for the Shuttle Imaging Radar C/X band SAR (SIR C/X SAR) science team.

In 1991, NASA, in collaboration with an Italian consortium (CORISTA), implemented an additional set of C band antennas to provide single-pass, fixed baseline, cross-track interferometry (XTI) for topographic mapping. In this single-pass system, called TOPSAR, two SAR images are acquired simultaneously with known baseline to produce accurate digital elevation models.

In 1995, TOPSAR was extended to acquire XTI data simultaneously in both C band and L band. The TOPSAR system can operate in either a single-baseline or dual-baseline modes. The single baseline mode transmits from one antenna with data reception from both antennas. The dual-baseline mode alternates transmission from either antenna with data reception from both antennas. The dual mode is commonly referred to as the ping-pong mode and offers a larger baseline for greater sensitivity for topographic mapping applications.

In 2004, JPL led a workshop to discuss potential enhancements to the AIRSAR system. One outcome of this meeting was a strong interest in repeat-pass interferometry for studying surface deformation in the study of natural hazards. Another outcome was the submission of a successful proposal to use an Unmanned Aerial Vehicle (UAV) as a platform for future SAR missions, in order to achieve operational cost savings. In response to this new initiative, the AIRSAR mission support was outsourced from NASA Langley to the University of North Dakota.

POLSAR Products In polarimetric mode, AIRSAR is capable of acquiring full polarimetric returns for each of three bands (C , L , and P bands). The antenna switching network for each radar band is setup to acquire data from both H and V polarized antennas simultaneously. Quad-polarization (HH, HV, VH, and VV) is achieved by alternating the transmit signal between H and V polarization while receiving on both antennas.

AIRSAR data provided the earth science community an ability to evaluate potential applications of polarimetric SAR. This was critical in the early development years when polarimetry was less developed than today. Only recently has fully polarimetric data become available in high quantities with the European Space Agency’s (ESA) Envisat satellite and the soon-to-be-launched Advanced Land Observing Satellite (ALOS) and RADARSAT 2 satellites.

POLSAR data has supported much of the algorithm development for polarimetry. Research spanning the last two decades has shown that radar polarimetry can provide unique information on the shape and distribution of scattering elements within a resolution element. Such information is of potential value to a wide variety of earth science applications, including geology, ice mapping, forestry, and agriculture.

Two, personal computer (PC)-based visualization tools, Sigma0 and MAPVEG, have been developed and made available to AIRSAR users. Classification images generated by MAPVEG can be used to separate vegetated from non-vegetated areas, which may be useful in determining the soil moisture for areas free of vegetation. In addition, MAPVEG can separate forests from the surrounding vegetation and can be used to identify clear-cut areas. Urban areas and marshlands are other examples of identifiable classes.