Seasat Rediscovered: ASF DAAC Imagery from 1978 Data
Launched by NASA in 1978, the Seasat satellite’s primary mission was to observe oceans using NASA’s first synthetic aperture radar (SAR) sensor. SAR bounces a microwave radar signal off the surface of Earth to detect physical properties. Unlike optical photo technology, SAR can see through darkness, clouds, and rain.
Through the use of SAR, the Seasat satellite collected an enormous amount of data for its time. This data has been processed by the Alaska Satellite Facility, a NASA Distributed Active Archive Center (DAAC), into digital imagery that allows scientists to measure features of the planet’s surface over time.
ASF is a NASA Distributed Active Archive Center (DAAC) specializing in synthetic aperture radar data.
Seasat – About
Seasat was the first NASA satellite with synthetic aperture radar deployed….
Seasat – Glossary
A glossary of terms used in the Seasat project…
Seasat – How to Cite
Citing Seasat Data Cite data in publications such as journal papers, articles, presentations, posters, and websites. Please send copies of, or links to, published works citing data, imagery, or tools accessed…
Seasat – Images Then and Now
Before and After Images showing the difference between the Seasat images being optically processed shortly after the mission and digitally processed in 2013…
Seasat – Processing and Tools
Seasat data required cleaning before processing it into imagery….
Seasat – Product Specification Guide
During its brief 106-days of lifetime, the Seasat-1 spacecraft, launched on June 28, 1978, by NASA’s Jet Propulsion Laboratory (JPL), collected information on sea-surface winds, sea-surface temperatures, wave heights, internal waves, atmospheric water, sea ice features, ice sheet topography, and ocean topography….
Seasat – References
View Seasat technical reports, general references, and publications focused on Seasat data processing, oceans, snow and ice, and land applications….
Seasat – Swath Coverage Maps
The Seasat satellite was designed to cover areas up to 75° north latitude….
Seasat – Technical Challenges
The Alaska Satellite Facility was tasked by NASA with creating a digital archive of focused synthetic aperture radar (SAR) products from data collected by NASA’s Seasat mission….
Seasat – Technical Challenges – 1. Raw Telemetry
Seasat was not equipped with an onboard recorder, so in order to collect data during the mission, three U.S….
Seasat – Technical Challenges – 10. Quality Issues
After the decoding, cleaning and focusing of the Seasat SAR data, many artifacts still exist in the initial ASF Seasat SAR products….
Seasat – Technical Challenges – 11. Data Product Formats
This section provides a detailed description of the HDF5 data format used for the final generation of Seasat synthetic aperture radar (SAR) products….
Seasat – Technical Challenges – 2. Decoder Development
Starting in the summer of 2012, ASF undertook the significant challenge of developing a Seasat telemetry decoder in order to create raw data files suitable for focusing by a synthetic…
Seasat – Technical Challenges – 3. Decoded Data Analysis
With the Seasat archives decoded into range line format along with an auxiliary header file full of metadata, the next step is to focus the data into synthetic aperture radar…
Seasat – Technical Challenges – 4. Data Cleaning (Part 1)
In order to create a synthetic aperture for a radar system, one must combine many returns over time….
Seasat – Technical Challenges – 4. Data Cleaning (Part 2)
4.3 Prep_Raw.sh After development of each of the software pieces described previously in this section, the entire data cleaning process was driven by the program prep_raw.sh….
Seasat – Technical Challenges – 5. Classification of Bad Data
In spite of all of the work done to decode and clean data, many errors remained in the supposedly fixed files that had been decoded and multi-pass filtered….
Seasat – Technical Challenges – 6. Slope Issues
During decoding and cleaning, it was assumed that the time slope of the files would be roughly guided by the Pulse Repetition Interval (PRI) of the satellite, i.e….
Seasat – Technical Challenges – 7. Cleaned Swath Files
Seasat synthetic aperture radar (SAR) data holdings at ASF have been converted from their original 29 SONY SD1-1300L tapes into raw swath files with external metadata stored on disk….
Seasat – Technical Challenges – 8. Focusing Challenges
In modern systems, synthetic aperture radar (SAR) echoes are sampled in a complex fashion using IQ-demodulation….
Seasat – Technical Challenges – 9. From Swaths to Products
At this stage in the development of the ASF Seasat Processing System (ASPS): 1,346 cleaned raw signal swaths were created; ROI was modified to handle Seasat offset video format; New state vectors were selected for use over two-line elements (TLE’s); Caltones were filtered from the range power spectra; Data window position files were created…