Development of a MODIS direct broadcast reception and processing system

Abstract

Since the successful launching of the TERRA satellite in late 1999, CRISP has been preparing to receive MODIS data in Direct Broadcast mode. A multi-mission demodulator with SPOT, ERS, TERRA and AQUA capabilities has been purchased and integrated into CRISP's antenna system. The output of the demodulator is directly recorded on the existing direct ingest system (disk arrays). A reformatting program, with the option of performing Reed Solomon error correction, has been written to convert the recorded signal data into MODIS level-0 formatted data. This level-0 data is then fed into a level 1 processing program. Two versions of the level 1 processing software have been tested IMAPP by the University of Wisconsin and NASA GSFC MODIS level 1 Processing Software. One of the inputs for the NASA software is the construction record generated by a Windows-based program - Sorcerer. In order to integrate all our processing on the Unix platform, a small program that is able to generate the construction record has been written. We have found that the IMAPP software runs faster but the geolocationing is not very accurate. As for the NASA software, the geolocationing is fairly accurate, but a shortcoming is that its calibration process, MOD02, can only handle a granule size of 300 seconds. Therefore, we replace the geolocation produced by IMAPP by NASA's geolocation and further calibrate the results into level 1b using IMAPP software. A georectification code has also been developed to georectify the level 1b products onto a map. Another development is the generation of browse images directly from the level-0 data. The generated browsed images together with its meta files are sent to a web-based Catalog Browse System. The acquisition, archival, browse image generation and catalog updating are performed automatically.