Aqua AIRS/AMSU/HSB Processing Package for Direct Broadcast

Part of the International MODIS/AIRS Processing Package (IMAPP)

July 23, 2008: Version 5.2.1 released


    The polar-orbiting Aqua spacecraft, launched by NASA in May 2002, provides an X-band direct broadcast service where data from all science instruments is downlinked to the Earth in near real-time. The AIRS/AMSU/HSB Processing Package for Direct Broadcast allows any ground station capable of receiving direct broadcast from Aqua to produce calibrated and geolocated AIRS, AMSU, and HSB Level 1B (calibrated and geolocated instrument observations) and Level 2 (geophysical retrieval) products.

    AIRS Direct Broadcast v5.2.1 is a special v5 delivery to allow Level-2 retrievals to be performed even though one of the AMSU-A channels it relies upon has degraded seriously. It compensates by replacing the noisy AMSU-04 channel with a synthetic channel made via regression from other AMSU-A channels. This package (v5.2.1) is functionally identical to the operational AIRS/AMSU/HSB software running at the GSFC DAAC (v5.2.2), with the following additions:

        This package was developed by the AIRS Team at NASA Jet Propulsion Laboratory. Distribution and support is provided by the Space Science and Engineering Center at the University of Wisconsin-Madison.


    This is a binary-only release for Intel Linux platforms. No source code is included. This version of the package has been tested on the following platforms:

    The input expected by the package is Level 0 AIRS, AMSU, HSB, and GBAD files, defined as reconstructed time-ordered CCSDS packets with all communication artifacts (including duplicate and bad packets) removed. This includes PN and Reed Solomon decoding as well as reassembly of the raw telemetry packets. Processing of the data stream to this stage is the responsibility of the user. Data in this format is known as a Production Data Set (PDS).
    The Direct Readout Laboratory at NASA GSFC has developed a software application named RT-STPS (Real-Time Software Telemetry Processing System), which synchronizes the data, performs PN and RS decoding and packet reassembly, and writes the output in PDS format. This package is know to be compatible with Level 0 PDS files created by RT-STPS. In addition, many X-band ground station vendors supply processing hardware and/or software that creates compatible Level 0 files.

Installation and Operation

    The package is available for download through the IMAPP download page

    Please see the README file for instructions on installing and running the package. If you are unable to download the package because of a slow Internet connection, please contact us and we will arrange to ship the package to you on DVD media. This package is released under the terms of a NASA GSFC Software Release and Usage Agreement.

File Formats

    The format of the AIRS, AMSU, and HSB Level 1B and Level 2 output files is identical to the format of the equivalent GSFC DAAC files. The format is HDF-EOS, and all ECS metadata fields are present. Regardless of the size of the direct broadcast pass, the output files will be split into standard AIRS 6-minute granules. Therefore the leading and/or trailing granules created from a direct broadcast pass will contain some missing data.


    This package was developed at NASA Jet Propulsion Laboratory by Quyen Nguyen, Richard Forrister and Evan Manning.
    This package is supported at SSEC by Liam Gumley, Allen Huang, and Kathy Strabala, as part of the International MODIS/AIRS Processing Package (IMAPP).

Related Links for AIRS/AMSU/HSB

Level 0 data:
    Univ. of Wisconsin | NASA GSFC

Level 1B and Level 2 data:
    Univ. of Wisconsin | GSFC DAAC Data Pool

    Home | AIRS Products

Aqua spacecraft:
    Home | Orbit Tracks | Overpass Prediction | NORAD TLE orbital elements

Kathy Strabala (last update July 23, 2008)