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.
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EO Data Access
