Remote-sensing is the practice of recording objects or environmental phenomena (sensing) from a far-away place (remote). So, satellite remote-sensing refers to the practice of using satellites or drones to collect information about objects or remote phenomena within the instantaneous-field-of-view (IFOV) of a sensor system. The sensor system, of course, is located on the satellite, space shuttle, rocket, or drone.
Basically, the sensor on a satellite platform records the electromagnetic energy reflected by the object or target. There are two types of sensors. Passive sensors are used when naturally-occurring energy is available (for example, when the sun is shining during the day). Active sensors, on the other hand, can be used at any time of the day or night. These sensors work by emitting radiation towards the target in question. Reflected radiation from the target is then measured by the sensor.
The sensors record radiation all across the electromagnetic spectrum; unlike the human eye (which can only detect visible light), these special sensors can detect infrared and ultraviolet light. The reflected radiation from the target object is then turned into images and used as a surrogate for the actual target. Invisible light such as infrared or ultraviolet light are represented by different colors in satellite images. In order to interpret these images, scientists turn to visual or digital image processors. This is the basic process of acquiring data through remote-sensing satellite technology.
An example of how remote-sensing technology can benefit daily life is in the area of hurricane or storm forecasting. Since tropical hurricanes and cyclones often cost billions of dollars in property damage and the loss of countless lives, remote-sensing technology is crucial to public safety. Gathered data over decades has allowed scientists to forecast when these dangerous storms will make landfall; this allows the public to prepare and to leave affected areas before they do. Scientists can also track, examine, and study these decades of satellite data to determine patterns of hurricane and storm formation.
For more on the uses of remote-sensing satellite technology, please refer to the links below.