- Title: Satellite
- Identifier: sat
- Field Name Prefix: sat
- Scope: Item
- Extension Maturity Classification: Proposal
This document explains the fields of the Satellite Extension to a STAC Item. Sat adds metadata related to a satellite that carries an instrument for collecting data. It will often be combined with other extensions that describe the actual data, such as the eo, os or sar extensions.
The Satellite extension requires the Instrument Fields.
| Field Name | Type | Description |
|---|---|---|
| sat:orbit_state | string | The state of the orbit. Either ascending or descending for polar orbiting satellites, or geostationary for geosynchronous satellites |
| sat:relative_orbit | integer | The relative orbit number at the time of acquisition. |
At least one of the fields must be specified.
sat:orbit_state indicates the type and current state of orbit. Satellites are either geosynchronous in which case they have one state: geostationary, or they are sun synchronous (i.e., polar orbiting satellites) in which case they are either ascending or descending. For sun synchronous satellites it is daytime during one of these states, and nighttime during the other.
sat:relative_orbit is a count of orbits from 1 to the number of orbits contained in a repeat cycle, where relative orbit 1 starts from a specific reference location of the sub-satellite point (the point on the earth directly below the satellite). It resets to 1 when the sub-satellite point revisits the refernece location.
- No implementations yet
The extensions page gives an overview about related extensions. Of particular relevance to sat data.