(ATBD) SMAP Level 1 Radar Data Products - NASA
(ATBD) SMAP Level 1 Radar Data Products - NASA
(ATBD) SMAP Level 1 Radar Data Products - NASA
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Contents<br />
1 Introduction 1<br />
2 Mission and Instrument Overview 1<br />
2.1 Background and Science Objectives . . . . . . . . . . . . . . . . . 1<br />
2.2 Measurement Approach . . . . . . . . . . . . . . . . . . . . . . . . 2<br />
2.3 L1 Processing Requirements . . . . . . . . . . . . . . . . . . . . . 6<br />
3 L0 Processing 6<br />
4 L1 Processing Flow and Algorithm Interfaces 8<br />
4.1 Sources of <strong>Data</strong> . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8<br />
4.1.1 Geometry <strong>Data</strong> . . . . . . . . . . . . . . . . . . . . . . . . 8<br />
4.1.2 Instrument <strong>Data</strong> . . . . . . . . . . . . . . . . . . . . . . . . 10<br />
4.1.3 Processing Parameters . . . . . . . . . . . . . . . . . . . . 10<br />
4.2 Output <strong>Data</strong> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10<br />
4.2.1 L1B Product Description . . . . . . . . . . . . . . . . . . . 10<br />
4.2.2 L1C Product Description and Swath Grid . . . . . . . . . . 12<br />
4.3 Bit Flags in L1B and L1C products . . . . . . . . . . . . . . . . . . 13<br />
5 <strong>Data</strong> Characteristics and <strong>Radar</strong> Performance 17<br />
5.1 <strong>Radar</strong> Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . 17<br />
6 Point Target Response and Time Range Definitions 23<br />
6.1 <strong>Radar</strong> RF Signal Generation . . . . . . . . . . . . . . . . . . . . . 23<br />
6.2 Basebanded Point Target Response . . . . . . . . . . . . . . . . . . 26<br />
6.3 Forward and Backward Swath Row Time Range . . . . . . . . . . . 28<br />
6.4 Forward and Backward Looks Time Ranges . . . . . . . . . . . . . 30<br />
6.5 Synthetic Aperture Time . . . . . . . . . . . . . . . . . . . . . . . 30<br />
6.6 Impulse Response Time . . . . . . . . . . . . . . . . . . . . . . . . 31<br />
7 L1C Processing Algorithms 31<br />
7.1 Image Formation Theoretical Background . . . . . . . . . . . . . . 31<br />
7.2 High <strong>Level</strong> Algorithm Organization and the Direct Correlation Algorithm<br />
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33<br />
7.3 BFPQ Decoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35<br />
7.4 Geometry Processing and Interpolation . . . . . . . . . . . . . . . . 37<br />
7.5 Range Compression . . . . . . . . . . . . . . . . . . . . . . . . . . 37<br />
7.5.1 RFI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38<br />
7.6 Azimuth Phase Correction . . . . . . . . . . . . . . . . . . . . . . 38<br />
7.7 Azimuth Compression . . . . . . . . . . . . . . . . . . . . . . . . 39
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