Across-Track Scanner


An Across-Track Scanner, also known as a whiskbroom scanner, is a specific type of scanning device used in remote sensing technology to capture data in a swathe perpendicular to the direction of the flight path. In this system, the movement of the rotating mirror controls the scanning. The scanner scans the ground surface in lines from one side to the other, creating a sequential stream of data. Ultimately, this data forms a two-dimensional image, giving a broad perspective from the nadir to the edges of the ground swath.

What is an Across-Track Scanner?

An Across-Track scanner is a form of remote sensor used in earth observation satellites and aircraft. It collects information about the Earth's surface in a series of continuous, parallel lines known as scan lines. These scan lines run perpendicular to the flight path, forming a right angle with the direction of travel.

The system works by using a rotating mirror to reflect incoming light onto a sensor. As the mirror moves, it essentially "sweeps" across a given field of view, capturing data in a pattern resembling a broom's bristles—hence the name 'whiskbroom scanner'. The advantage of this type of scanner is that it utilizes a single detector, which ensures a consistent response to the reflected light, resulting in precise and reliable information about the observed surface.

An across-track scanner is commonly used in meteorological observations, land-use land-cover mapping and monitoring, environmental studies, and other fields that require the capture of detailed geospatial data.


What is the advantage of an Across-Track Scanner over an Along-Track Scanner?

The primary advantage of an Across-Track scanner over an Along-Track scanner is the consistency in observation. Because it uses a single detector, it ensures a consistent response for each pixel, making it more accurate in terms of reflectance values.

What are the applications of an Across-Track Scanner?

Applications of an Across-Track Scanner include weather and climate research, agriculture, forestry, oceanography, and other fields that require detailed mapping of the Earth's surface.

How does an Across-Track Scanner work?

The Across-Track Scanner works by reflecting incoming light onto a sensor using a rotating mirror. This mirror sweeps across a given field of view, capturing data over a wide swathe of area perpendicular to the direction of the flight.

What is the drawback of an Across-Track Scanner?

While Across-Track Scanners provide high-quality data, they can be limited by their relatively slower data acquisition speed when compared to Along-Track scanners. They require more time to cover the same area due to the sweeping motion of the mirror.

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