Whiskbroom vs Pushbroom Sensors: Key Differences Explained

This article compares Whiskbroom and Pushbroom sensors, outlining the key differences between these scanner types used in remote sensing.

Whiskbroom Sensor

Figure 1: Whiskbroom Sensor

The Whiskbroom sensor, as shown in Figure 1, utilizes a linear or area array of detectors. The image is constructed through the satellite’s movement along its orbital track and by cross-track scanning using a mirror.

Example: LANDSAT MSS/TM

The cross-track scanner employs a “back and forth” motion of the fore-optics, scanning each ground resolution cell individually. The Instantaneous Field of View (IFOV) of the instrument determines the pixel size.

Pushbroom Sensor

Figure 2: Pushbroom Sensor

Figure 2 illustrates the Pushbroom sensor, also known as an along-track scanner. This type of sensor uses a linear array of detectors aligned cross-track.

Here, reflected radiance passes through a lens and onto a line of detectors, eliminating the need for a scanning mirror. The image is constructed by the satellite’s movement along its orbital track.

Example: SPOT HRV (High Resolution Visible)

In this sensor type, an area array can also be used for multi-spectral remote sensing. Dispersion is used to split light into narrow spectral bands and direct it to individual detectors.

Comparison Table: Whiskbroom Sensor vs. Pushbroom Sensor

Feature	Whiskbroom Sensor	Pushbroom Sensor
Swath Width	Wide	Narrow
Mechanical System	Complex	Simple
Optical System	Simple	Complex
Components	Filters and sensors	Dispersion grating & CCDs
Dwell Time	Shorter	Longer
Pixel Distortion	Yes	No