Question 6 of 6intermediate💡 UnderstandShort Answer3 marks

Describe in brief the functioning of pushbroom scanner.

Correct Answer

Pushbroom scanners consist of a number of detectors which are equivalent to the number obtained by dividing the swath of the sensor by the size of the spatial resolution. For example, the French remote sensing satellite SPOT has 3000 detectors deployed in its HRV-1 sensor, calculated by dividing its 60 km swath by 20 metres spatial resolution.

In a pushbroom scanner, all detectors are linearly arrayed. Each detector collects the energy reflected by the ground cell (pixel) at a nadir's view. This linear arrangement allows the scanner to capture data across the entire swath simultaneously without using a rotating mirror.

Exercise: EXERCISE | Q: 2(iii) | (Page Page 22)
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Explanation

The answer draws directly from the textbook context which explains that pushbroom scanners use multiple detectors arranged linearly (linearly arrayed). The number of detectors is determined by dividing the swath width by spatial resolution. The example of SPOT HRV-1 with 3000 detectors is explicitly mentioned in the text. The key distinction from whiskbroom scanners is that pushbroom scanners don't use rotating mirrors - instead, each detector in the linear array captures energy from its corresponding ground cell simultaneously.

Solution Steps

  1. Step 1: Identify the key components of pushbroom scanners from context - multiple detectors arranged linearly

  2. Step 2: Explain how the number of detectors is calculated (swath ÷ spatial resolution)

  3. Step 3: Describe how each detector collects reflected energy from its corresponding ground cell at nadir view

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