3.3 Imagery standards
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SensorML does not provide a detailed description of the hardware design of a
sensor but rather it is a general schema for describing a functional model of the sensor.
SensorML supports both rigorous sensor models (sensor reference) and functional
fit models (image reference). In the case of rigorous sensor models, the description
ofthe sensor is typically separated from that ofits platform.
Sensor Identification
The root for all SensorML documents is the Sensor and the sensor description is
divided into main components of information, including:
• Sensor identification
• Document constraints like classification level or use restrietions
• Platform to which the sensor is attached
• Location ofthe sensor relative to a Coordinate Reference System
• Observable that can be measured
• Sensor's response characteristics like sensitivity
• Geometrie and temporal characteristics ofthe sampies
• Operator and Sensor Planning Service
• Sensor description such as serial number
• Documentation description such as author and modifications
Sensor models
Currently the SensorML describes the in-situ sensor case and three specific remote sensor models. These three models include (I.) the ScannerlProfiler Model, (2.)
the Optical Camera Model, and (3.) the Rapid Positioning Coordinate.
1. ScannerlProfiler Model
The line-of-sight sensor is the simplest profiler, consisting of essentially a single
look direction. Examples of line-of-sight sensors include altimeters and range
finders, ground-based atmospheric sounders, and non-sweeping Lidar.
Conic scanners include those sensors that scan by sweeping around a rotation axis
producing a cone pattern relative to the target body. Examples of conic scanners
include SSMII (ID) that sweeps around a single axis at a constant elevation angle.
Line-scanners sampie by sweeping around a rotation axis in such a way as they
sampie a linear array relative to the target. This is perhaps the most common sensor system used for lower resolution Earth observation. Examples are A VHRR
andMODlS.
The imager class of sensors can be considered a special case of line or conicscanners in which the entire array of pixels is sampled at one instant in time. Examples are push-broom and CCD array sensors.
109
SensorML does not provide a detailed description of the hardware design of a
sensor but rather it is a general schema for describing a functional model of the sensor.
SensorML supports both rigorous sensor models (sensor reference) and functional
fit models (image reference). In the case of rigorous sensor models, the description
ofthe sensor is typically separated from that ofits platform.
Sensor Identification
The root for all SensorML documents is the Sensor and the sensor description is
divided into main components of information, including:
• Sensor identification
• Document constraints like classification level or use restrietions
• Platform to which the sensor is attached
• Location ofthe sensor relative to a Coordinate Reference System
• Observable that can be measured
• Sensor's response characteristics like sensitivity
• Geometrie and temporal characteristics ofthe sampies
• Operator and Sensor Planning Service
• Sensor description such as serial number
• Documentation description such as author and modifications
Sensor models
Currently the SensorML describes the in-situ sensor case and three specific remote sensor models. These three models include (I.) the ScannerlProfiler Model, (2.)
the Optical Camera Model, and (3.) the Rapid Positioning Coordinate.
1. ScannerlProfiler Model
The line-of-sight sensor is the simplest profiler, consisting of essentially a single
look direction. Examples of line-of-sight sensors include altimeters and range
finders, ground-based atmospheric sounders, and non-sweeping Lidar.
Conic scanners include those sensors that scan by sweeping around a rotation axis
producing a cone pattern relative to the target body. Examples of conic scanners
include SSMII (ID) that sweeps around a single axis at a constant elevation angle.
Line-scanners sampie by sweeping around a rotation axis in such a way as they
sampie a linear array relative to the target. This is perhaps the most common sensor system used for lower resolution Earth observation. Examples are A VHRR
andMODlS.
The imager class of sensors can be considered a special case of line or conicscanners in which the entire array of pixels is sampled at one instant in time. Examples are push-broom and CCD array sensors.