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AATSR Data Formats Products
SST record 50 km cell MDS
BT/TOA Sea record 17 km cell MDS
Vegetation fraction for Land Surface Temperature Retrieval GADS
Topographic Variance data for Land Surface Temperature Retrieval GADS
Land Surface Temperature retrieval coefficients GADS
General Parameters for Land Surface Temperature Retrieval GADS
Climatology Variance Data for Land Surface Temperature Retrieval GADS
Level 0 SPH
Level 0 MDSR
Auxilliary Data SPH with N = 1
1.6 micron nadir view MDS
Summary Quality ADS
Scan pixel x and y ADS
Grid pixel latitude and longtitude topographic corrections ADS
Across-track Band Mapping Look-up Table
Configuration Data GADS
Processor configuration GADS
LST record 50 km cell MDS
Distributed product MDS
Level 2 SPH
10-arcminute mds
Limits GADS
Validation Parameters GADS
BT/TOA Land record 17 km cell MDS
General Parameters GADS
Temperature to Radiance LUT GADS
Radiance to Brightness Temperature LUT GADS
Medium/High Level Test LUT GADS
Infrared Histogram Test LUT GADS
11 Micron Spatial Coherence Test LUT GADS
11/3.7 Micron Nadir/Forward Test LUT GADS
11/12 Micron Nadir/Forward Test LUT GADS
Characterisation GADS
Browse Day_Time Colour LUT GADS
Browse SPH
Grid pixel latitude and longtitude topographic correction ADS
Level 2 SPH
Auxilliary Products
ATS_VC1_AX: Visible Calibration data
ATS_SST_AX: SST Retrieval Coeficients data
ATS_PC1_AX: Level-1B Processing configuration data
ATS_INS_AX: AATSR Instrument data
ATS_GC1_AX: General Calibration data
ATS_CH1_AX: Level-1B Characterization data
ATS_BRW_AX: Browse Product LUT data
Level 0 Products
ATS_NL__0P: AATSR Level 0 product
Browse Products
ATS_AST_BP: AATSR browse image
Level 1 Products
ATS_TOA_1P: AATSR Gridded brightness temperature and reflectance
Level 2 Products
ATS_NR__2P: AATSR geophysical product (full resolution)
ATS_MET_2P: AATSR Spatially Averaged Sea Surface Temperature for Meteo Users
ATS_AR__2P: AATSR averaged geophysical product
Frequently Asked Questions
The AATSR Instrument
Instrument Characteristics and Performance
In-flight performance verification
Instrument Description
Internal Data Flow
Instrument Functionality
AATSR Products and Algorithms
Common Auxiliary data sets
Auxiliary Data Sets for Level 2 processing
Instrument Specific Topics
Level 2 Products
Level 1B Products and Algorithms
Level 1B Products
Instrument Pixel Geolocation
The Level 0 Product
Differences Between ATSR-2 and AATSR Source Packets
Definitions and Conventions
Organisation of Products
Relationship Between AATSR and ATSR Products
AATSR Product Organisation
Data Handling Cookbook
Characterisation and Calibration
Monitoring of AATSR VISCAL Parameters
Latency, Throughput and Data Volume
Data Processing Software
Data Processing Centres
The AATSR Products User Guide
Image Gallery
Breakup of the Ross Ice Shelf
Land cover in the Middle East
Typhoon Saomai
Mutsu Bay, Japan
Deforestation in Brazil
Spatially Averaged Global SST, September 1993
Further Reading
How to use AATSR data
Why Choose AATSR Data?
Why Choose AATSR Data?
Special Features of AATSR
Principles of Measurement
Scientific Background
The AATSR Handbook
SST record 17 km cell MDS
Surface Vegetation class for Land Surface Temperature Retrieval GADS
1.6 micron forward view MDS
12 micron nadir view MDS
12 micron forward view MDS
Summary Quality ADS
Surveillance Limits GADS
Master Unpacking Definition Table GADS
1.6 micron Non-Linearity Correction LUT GADS
General Parameters GADS
Thin Cirrus Test LUT GADS
Fog/low Stratus Test LUT GADS
1.6 Micron Histogram
Browse MDS
ATS_CL1_AX: Cloud LUT data
Pre-flight characteristics and expected performance
Payload description, position on the platform
Auxiliary products
Auxiliary Data Sets for Level 1B processing
Summary of auxiliary data sets
Calculate Solar Angles
Image Pixel Geolocation
Level 0 Products
Acquisition and On-Board Data Processing
Product Evolution History
Hints and Algorithms for Higher Level Processing
Data Volume
Software tools
Summary of Applications vs Products
Geophysical Coverage
Geophysical Measurements
Visible calibration coefficients GADS
Level 1B SPH
LST record 17 km cell MDS
Conversion Parameters GADS
12 Micron Gross Cloud Test LUT GADS
ATS_PC2_AX: Level-2 Processor Configuration data
Level 2 Products
Hints and Algorithms for Data Use
BT/TOA Sea record 50 km cell MDS
BT/TOA Land record 50 km cell MDS
Level 2 Algorithms
Signal Calibration
Site Map
Frequently asked questions
Terms of use
Contact us


3.1.3 Internal Data Flow

Figure3.7 shows the acquisition and flow sequence for AATSR observation and calibration data.

AATSR Internal Data Flow
Figure 3.7 ATSR acquisition and flow sequence for instrument observation and calibration data

The data flow for AATSR is as follows:

Figure 3.8 AATSR San Cycle
Scan cycle (7K)

(This is an image map, so clicking on a part of AATSR will take you to detailed information about it)

  • The radiation is focussed onto the cooled Focal Plane Assembly by the instrument optics and beamsplitters. The low level signals which are proportional to the radiation intensity are amplified by a Signal Preamplifier.

  • These signals are in turn passed to the Instrument Electronics Unit (IEU) where the signals have gain and offset adjustments made. The gain and offset adjustments are made autonomously by the ICU for the IR channels (Auto Gain/Offset (AGO)) by sampling the digital data within the Digital Electronics Unit (DEU) corresponding to the hot and cold calibration target radiances for each IR channel. For the visible channels, offset adjustments are made autonomously by the ICU by sampling the digital data within the DEU corresponding to the cold calibration target radiances for each visible channel (Auto Offset). Visible channel gain adjustments are made by macrocommand following analysis of the ground processed source packet data at the time of sun illumination of the visible calibrator.

  • The signals for each channel are then integrated over sample periods, each of 75µs, by a pair of integrators operating alternately. This integration provides a total of 2000 pixels per revolution (scan) of the scan mirror. Each of the integrated data samples is then converted from analogue to 12 bit digital data. In order to distinguish between the 2000 pixels in a scan, the clock generator electronics (in the IEU ) produces a 'Scan Sync' pulse synchronised to pixel location 1 and a 'Pixel Sync' pulse for each of the 2000 pixels.

  • The 12 bit data from each signal channel are passed serially to the DEU where the pixel data are selected for formatting in accordance with a pixel map held in a dedicated non-volatile memory within the DEU. The map is a look up table with one entry for each of the 2000 pixels in a scan. The map identifies whether or not to format science data for each pixel. Of the 2000 pixels in a 360° rotation of the instrument scan mirror, 974 of these pixels contain useful data i.e. Earth viewing and calibration source radiances. Some pixels represent views of the instrument housing/structure and are therefore discarded. Table 3.1 below shows the pixel selection map at launch - this may be updated during commissioning (see section ).

Table 3.1 Pixel Selection Map at Launch
Region Used Pixels
Viscal 75-90
Nadir View 224-778
+X BB 1074-1089
Forward View 1316-1686
-X BB 1913-1928
  • Two bits of blanking pulse data, one from each of Radar Altimeter-2 (RA-2) and the Advanced Synthetic Aperture radar (ASAR) instruments, are merged with the selected pixel data. Blanking pulses only occur in the merged data for those pixels which were being integrated during the occurrence of a blanking pulse and are included to allow possible data discrepancies to be tied in with transmissions from the RA-2 and the ASAR. The observation and calibration data are combined with blanking pulse data, additional header data and auxiliary data to produce a packet of information in a predetermined format, known as a source packet2.2 . Each source packet has a length of 5756 x 16 bits. These packets are automatically transferred every 150ms at a clock rate of 625 kbits/s to the spacecraft's High Speed Multiplexer (HSM) for onward transmission to the ground.