Active Sensor Vs Passive Sensor-Difference between Active Sensor,Passive Sensor

This page compares Active Sensor Vs Passive Sensor and mentions difference between Active Sensor and Passive Sensor types.

Definition: A sensor is a device which comprises of optical component or system and a detector with electronic circuits used to record reflected and/or emitted energy from various objects.

Active Sensor

• Active sensor emits their own EM (Electromagnetic) energy which is transmitted towards the earth and receives energy reflected from the earth. The received EM energy is used for measurement purpose.
• Examples: communication satellite, earth observation satellite (e.g. RADARSAT-1), LISS-1 etc.
• Active sensors use their own source of energy for operation.
• Active sensors can obtain measurements anytime (Day & Night).

Passive Sensor

• Passive sensor receives naturally emitted EM energy within its field of view (FIV) and performs measurement using it.
• Examples: remote sensing satellite, SPOT-1, LANDSAT-1 etc.
• Passive sensors rely own other sources such as sun for its operation.
• Passive sensors obtain measurements only in day time.

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