1 INTRODUCTION¶
1.1 Purpose and Scope¶
The scope of this document is to be used as an annex for the CSC Common Entity Definition Document [RD-2] in order to describe the POD files packaging, as well as the Product Entity Properties, the Product Attributes and the corresponding metadata elements that shall be catalogued and queryable, for all POD files circulating through the ESA EO Framework (EOF) Copernicus Space Component (CSC) [AD-1]. Additionally, the document describes the format of the POD products’ packages and the applicability to each Sentinel constellation.
1.2 Applicable Documents¶
| ID | Document Reference | Document Title |
|---|---|---|
| [AD-1] | ESA-EOPG-EOPGC-TN-58 | ESA EO Framework (EOF) – CSC - Data Flow Configuration |
Table 1-1 – Applicable Documents
1.3 Reference Documents¶
| ID | Document Reference | Document Title |
|---|---|---|
| [RD-1] | GMES-GSEG-EOPG-FS-10-0075 | Sentinels POD Service File Format Specifications |
| [RD-2] | ESA-EOPG-EOPGC-IF-5 | Copernicus Space Component - Common Entity Definition Document |
| [RD-3] | OGC 17-003r0 | OGC EO Dataset Metadata GeoJSON(-LD) Encoding Standard |
| [RD-4] | OGC 10-157r4 | OGC Earth Observation Metadata profile of Observations & Measurements |
Table 1-2 – Reference Documents
1.4 Acronyms, Definitions and Abbreviations¶
| Acronym | Description |
|---|---|
| ADF | Auxiliary Data Files |
| ADG | Auxiliary Data Gathering |
| CSC | Copernicus Space Component |
| DA | Data Access |
| EOF | ESA Earth Observation Framework |
| GNSS | Global Navigation Satellite System |
| GPSR | Global Positioning System Receiver |
| ICD | Interface Control Document |
| ILRS | International Laser Ranging Service |
| IPF | Instrument Processing Facility |
| JSON | JavaScript Object Notation |
| LTA | Long Term Archiving |
| NRT | Near Real Time |
| OSV | Orbit State Vectors |
| POD | Precise Orbit Determination |
| PR | Systematic Production |
| REP | Reprocessing timeliness (generated every ~4 months) |
Table 1-3 – Acronyms and Abbreviations
2 POD PRODUCTS OVERVIEW¶
This section presents an overview of the products and auxiliary files used or generated by the Sentinels POD Service with indication on the Sentinel Mission applicability.
The POD Service generates the following products:
POD Orbit Files, i.e. orbit state vectors (OSV) from the orbit determination performed by the Copernicus POD Service based on the GPSR input data.
Auxiliary Files, i.e. products requested by the Production Service to be used in support to the Mission data processing. These include attitude data files.
GNSS Lib files for all Sentinels. These are disseminated via the Data Access (DA) Service.
Quaternions Files for all Sentinels. These are disseminated via the Data Access Service.
The file naming convention, the file formats and the specifications for the files used or generated by the POD Service are described in detail in [RD-1].
| File Type | Description | Timeliness | Product Type | Format | S-1 | S-2 | S-3 | S-6A |
|---|---|---|---|---|---|---|---|---|
| POD Orbit Files | Predicted Orbit File | NRT | AUX_PREORB | .EOF | X | X | ||
| Restituted Orbit File | NRT | AUX_RESORB | .EOF | X | X | |||
| Medium Orbit Ephemerides (MOE) Orbit File | STC | AUX_MOEORB | .EOF .SEN3 (for S3) | X | X | |||
| Precise Orbit Ephemerides (POE) Orbit File | NTC | AUX_POEORB | .EOF .SEN3 (for S3) | X | X | X | ||
| NRT Restituted Orbit File | NRT | SR___ROE_AX | .SEN3 | X | ||||
| SALP MDO Orbit File | STC | SR___MDO_AX | .TGZ | X | ||||
| SALP POE Orbit File | NTC | SR___POE_AX | .TGZ | X | ||||
| Sentinel-6A NRT Orbit File | NRT | AX____ROE__AX | .SEN6.tar | X | ||||
| Sentinel-6A SALP MDO Orbit File | STC | AX____MOED_AX | .SEN6.tar | X | ||||
| Sentinel-6A SALP POE Orbit File | NTC | AX____POE__AX | .SEN6.tar | X | ||||
| Combined Orbit File | REP | AUX_COMB | .sp3 (plain ASCII file) | X | X | |||
| Auxiliary Files for Sentinels | Preliminary Platform Data for Sentinel-3 | STC | AUX_PRLPTF | .EOF .SEN3 (for S3) | X | |||
| Precise Platform Data for Sentinel-3 | NTC | AUX_PRCPTF | .EOF .SEN3 (for S3) | X | ||||
| NRT Platform Data for Sentinel-3 | NRT | SR_2_NRPPAX | .SEN3 | X | ||||
| GNSS L1b Files | Daily GNSS L1b RINEX files | STC | AUX_GNSSRD | .TGZ | X | X | X | X |
| Quaternions Files | Processed Quaternions Files | NTC | AUX_PROQUA | .TGZ | X | X | X | X |
Table 2-1 – POD Service Products and Auxiliary Data Files Overview vs. Sentinels mission
3 POD FILE ENTITY PROPERTIES MAPPING¶
[RD-2] defines the Generic CSC Common Entity Properties. Table 3-1 provides the mapping between these Generic Product Entity Properties and the Sentinels POD products metadata. Most of the Product Entity Properties do not map directly to the POD File metadata as they are generated by the CSC services.
| OData Product Entity Properties | Type | Description | Cardinality | Corresponding POD Files Metadata | Example |
|---|---|---|---|---|---|
| Name | String | Data file name (according to the Sentinel file naming conventions) plus the file extension | 1 | n/a Based on file name | S1B_OPER_AUX_GNSSRD_POD__20191124T02 1044_V20191116T235950_20191117T235940. TGZ |
| ContentDate | TimeRange | The sensing range period. Compound property with start and end times in UTC in the format YYYY-MM- DDThh:mm:ss | 1 | Validity_Period / Validity_Start Validity_Period / Validity_Stop | "ContentDate": { "Start":"2019-11-16T23:59:50", "End":"2019-11-17T23:59:40" } |
Table 3-1 – POD File Entity Properties mapping
4 POD FILES ATTRIBUTES MAPPING¶
All relevant metadata elements of the POD Files shall be indexed in the Product Attributes, additional metadata elements may also be identified if appropriate. In order to provide a harmonised model across the Sentinel missions the JSON property naming from [RD-3] is preferred for the Attributes Names. In case an attribute is not defined in [RD-3] the native naming used in the metadata is preferred. The Product Attributes mapping for the relevant POD Files is described in the Excel file “POD Product Attributes Mapping_v1.0”, which is packaged together with this document. A summary of the POD Product Attributes mapping is presented in Table 4-1 below. It should be highlighted that, in order to harmonise the metadata model across the Sentinel missions, in some cases an “alias” for the value defined in the POD Files metadata is mapped to a standardised value to be used by the EOF CSC services, in other cases a standard value is defined where it is otherwise unavailable from the product.
The External Auxiliary Data follow the data structure presented in section 3.2 of [RD-1]. The attributes for these files are mapped to the xfdumanifest.xml metadata file that is generated when these files are converted to the Sentinel-3 format. Therefore, they follow the structure and metadata of the Sentinel-3 Auxiliary data.
| OData Attribute Name | POD File Attributes Mapping | Applicability | |||||||
| POD Orbit Files | Auxiliary Files for Sentinels | GNSS L1b Files | Quaternions Files | POD | ADG | PR | LTA | DA | |
| beginningDateTime | x | x | x | x | x | x | x | x | x |
| endingDateTime | x | x | x | x | x | x | x | x | x |
| platformShortName | x | x | x | x | x | x | x | x | x |
| platformSerialIdentifier | x | x | x | x | x | x | x | x | x |
| productType | x | x | x | x | x | x | x | x | x |
| processingDate | x | x | x | x | x | x | x | x | x |
| processingCenter | x | x | x | x | x | x | x | x | x |
| processorVersion | x | x | x | x | x | x | x | x | x |
Table 4-1 – POD File Attributes Mapping Summary