This lesson is about ….
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Passive Systems
- Rely on the illumination of the Earth by the sun (or artificial light sources)
- Detect the reflection from the Earth’s surface
- Are very sensitive to cloud cover
- Need no internal energy source
Active Systems
- Provide illumination by sending out microwaves
- Are largely weather (cloud) independent
- Acquire images during day and night
- Actively control wavelength, frequency and polarisation of the transmitted signal
