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ASA_XCH_AX: ASAR External characterization data
ASA_XCA_AX: ASAR External calibration data
ASA_INS_AX: ASAR Instrument characterization
ASA_CON_AX: ASAR Processor Configuration
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ASA_WS__BP: ASAR Wide Swath Browse Image
ASA_IM__BP: ASAR Image Mode Browse Image
ASA_GM__BP: ASAR Global Monitoring Mode Browse Image
ASA_AP__BP: ASAR Alternating Polarization Browse Image
Level 0 Products
ASA_WV__0P: ASAR Wave Mode Level 0
ASA_WS__0P: ASAR Wide Swath Mode Level 0
ASA_MS__0P: ASAR Level 0 Module Stepping Mode
ASA_IM__0P: ASAR Image Mode Level 0
ASA_GM__0P: ASAR Global Monitoring Mode Level 0
ASA_EC__0P: ASAR Level 0 External Characterization
ASA_APV_0P: ASAR Alternating Polarization Level 0 (Cross polar V)
ASA_APH_0P: ASAR Alternating Polarization Level 0 (Cross polar H)
ASA_APC_0P: ASAR Alternating Polarization Level 0 (Copolar)
Level 1 Products
ASA_IMS_1P: ASAR Image Mode Single Look Complex
ASA_IMP_1P: ASAR Image Mode Precision Image
ASA_IMM_1P: ASAR Image Mode Medium Resolution Image
ASA_IMG_1P: ASAR Image Mode Ellipsoid Geocoded Image
ASA_GM1_1P: ASAR Global Monitoring Mode Image
ASA_APS_1P: ASAR Alternating Polarization Mode Single Look Complex
ASA_APP_1P: ASAR Alternating Polarization Mode Precision Image
ASA_APM_1P: ASAR Alternating Polarization Medium Resolution Image product
ASA_WSS_1P: Wide Swath Mode SLC Image
ASA_WVS_1P: ASAR Wave Mode Imagette Cross Spectra
ASA_WSM_1P: ASAR Wide Swath Medium Resolution Image
ASA_APG_1P: ASAR Alternating Polarization Ellipsoid Geocoded Image
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2.9.1 Summary of Auxiliary Data Sets

2.9.1.1 Auxiliary Data Files

Auxiliary data files are all other data files used to produce a product other than the direct measurements of the instrument. This may include calibration data that was measured on-board but is not part of the main measurement data of the instrument. It may also include external calibration files from sources other than the satellite, processor configuration files, and any other files needed by instrument processors. For a further discussion of the auxiliary data files refer to the section "Common Auxiliary Data Sets" 2.9.3. and "Auxiliary Data Sets for Level 1B Processing" 2.9.2.

2.9.1.2 Naming Strategy

The naming strategy for auxiliary data will be similar to the product naming conventions. The first 10 characters will be the auxiliary data ID, and will follow the following format:

WWW_XXX_YZ

WWW is the same instrument codes used for specifying product IDs. The instrument ID for auxiliary data indicates the instrument the data is intended for. Auxiliary data intended for several instruments will use the code AUX.

XXX is used to identify the type of auxiliary data.

YZ is always set to the letters AX for auxiliary data.

For auxiliary data, the file name structure contains:

The Auxiliary Data ID as described above (10 characters).

The Processing Stage flag which is used to indicate the quality level of the auxiliary data, using the same method as for the core products with N for preliminary quality up to V for highest quality (1 character).

The Originator ID indicates the source of the auxiliary data (3 characters). If not relevant, set to XXX.

The date and time of the auxiliary data creation (YYYYMMDD_hhmmss) (15 characters).

Underscore character (1 character).

The date and time when the auxiliary data becomes valid in the PDS (YYYYMMDD_hhmmss) (15 characters).

Underscore character (1 character).

The date and time when the auxiliary data ceases to be valid in the PDS (YYYYMMDD_hhmmss) (15 characters).

Note: The filename format above is 61 characters long. When the filename is written to field 1 of the MPH (which is 62 characters long) a blank space character is added at the end of the filename in order to fill the field.

Table 2.67 below provides a list of the auxiliary data files used in the ENVISAT PDS for ASAR processing.

Table 2.67 ENVISAT PDS Auxiliary Data Files used by ASAR
Aux_Data_ID
Approx. Size (MB)
Estimated Update Rate
Used by
Used for Comments
ASA_CON_AX
0.003
Infrequent
ASAR
L1B ASAR Processor Configuration file
ASA_INS_AX
0.163
Infrequent
ASAR
L1B Instrument characterisation file
ASA_XCA_AX
0.010
6 Months
ASAR
L1B ASAR External calibration data
ASA_XCH_AX
0.003
6 Months
ASAR
L1B ASAR External characterisation data
AUX_FRO_AX 2.9.3.1.
0.195
1 Day
All Instruments
L0, L1B, L2 Restituted orbit state vector
AUX_FPO_AX 2.9.3.1.
0.013
1 Day
ASAR and PF-HS
L0, L1B, L2 Predicted orbit state vector
DOR_POR_AX 2.9.3.2.
0.003
1 day
All Instruments
L1B DORIS Preliminary Orbit State Vectors
DOR_VOR_AX 2.9.3.3.
0.003
1 day
All Instruments
L1B DORIS Precise Orbit State Vectors

2.9.1.3 Auxiliary Data Structure

Auxiliary data files follow the same format guidelines as the PDS products. Every Auxiliary Data file will consist of an MPH, an SPHand one or more data sets.

Auxiliary data which originates outside the PDS will be wrapped in an MPH and SPH upon entry to the PDS. The actual contents of the foreign file will become those of a GADS, without modification.

2.9.1.4 Auxiliary Data MPH

The MPH used for auxiliary data is the same as that used for products. For auxiliary data which originates from the satellite, most of the MPH fields will be relevant. For auxiliary data which does not originate from the satellite, many sections of the MPH will not be relevant, and MPH fields not pertinent will be blanked or set to zero (depending on the field type) as shown in the MPH layout provided in the Data Formats 6.6.1. section.

Field 1 of the MPH will contain the name of the auxiliary data file using the auxiliary data naming strategy described in NAMING STRATEGY 2.9.1.2. above. Therefore, field 1 of the MPH will be constructed as follows:

Table 2.68 Field 1 of Auxiliary Data MPH Record
Field Description Units Byte Length Data Type
1
PRODUCT=
keyword 8 8*uc
quotation mark (") 1 uc
Auxiliary Data File Name (the following fields describe the contents of the auxiliary data filename) 62
10 character file ID - 10 10*uc
Processing stage flag - 1 uc
Originator ID (if not relevant, set to XXX) - 3 3*uc
creation_day (YYYYMMDD UTC creation day of the auxiliary file) - 8 8*uc
underscore character - 1 uc
creation_time (HHMMSS UTC creation time of the auxiliary file) - 6 6*uc
underscore character - 1 uc
valid_day (YYYYMMDD UTC day the auxiliary file becomes valid) - 8 8*uc
underscore character - 1 uc
valid_time (HHMMSS UTC time the auxiliary file becomes valid) - 6 6*uc
underscore character - 1 uc
invalid_day (YYYYMMDD UTC day the auxiliary file becomes invalid) - 8 8*uc
underscore character - 1 uc
invalid_time (HHMMSS UTC time the auxiliary file becomes invalid) - 6 6*uc
blank space character - 1 uc
quotation mark (") - 1 uc
newline character terminator 1 uc

2.9.1.5 Auxiliary Data SPH Structure

The structure of this header file is given in Data Formats.(Chapter 6. )

2.9.1.6 Auxiliary Data Sets

The Data Sets may be of any of the types described for PDS Products, and follow identical format rules. Any exceptions are noted in the individual file descriptions.