How Does Remote Sensing Work?
We come across remote sensing almost every day but actually we dodn’t realize it. This technology makes 3D earth models possible. We can use 3D topography maps and take virtual tours of famous monuments, thanks to remote sensing.
Furthermore, Remote sensing is actually a science of obtaining information about objects, However, this is done without any physical contact with them. In this technology Satellites or airplanes gather data via high-resolution cameras.
In addition, this technology has numerous applications. This technology is particularly helpful in geographical land surveying, military surveillance, and planning. It has commercial and economic applications as well. Remote sensing in the field of agriculture has tremendous potential. Various GIS Softwares also utilize this data for their applications.
The remote sensing technology works through various sensors. These sensors collect data from the energy reflected back from the earth. Generally, Satellites and airplanes carry these sensors.
Remote Sensors are classified as active sensors and passive sensors. Active sensors usually emit some form of energy or radiation. Then the active sensor detects energy reflected back from the target. While on the other hand, passive sensors utilize a natural source of energy to gather data of the surroundings. So, active sensors have own source of energy while passive sensors use a natural source of energy to detect objects.
Passive remote sensing
The passive sensing uses a natural source of energy. The most common example is the camera. The camera uses sunlight as a source of energy. It harnesses reflected radiation from sunlight to gather data in the form of a photograph. We can then classify objects via images taken from cameras.
This type of sensing consumes less energy. Hence, passive remote sensing is more efficient and handy. Furthermore, infrared, radiometers and charge-couple devices are passive remote sensors.
Active remote sensing
Active remote sensors use own source of energy to detect objects. The most common example is RADAR and LiDAR. Both of them emit some form of energy. They particularly calculate the time delay between emission and reception of radiation.
Furthermore, the active sensors emit energy to scan the object and areas. Then the active sensor measures energy reflected back from the object. This type of sensing requires more resources and energy. In addition, this type of remote sensing is now increasingly common in autonomous vehicles.
Uses of Sensing Technology
The most common and traditional use of this technology is the RADAR. RADAR is common in air traffic control and the collection of large scale metrology data. Doppler Radars has the ability to show live cloud conditions in specific areas. This radar even shows wind speeds.
Laser and radar altimeters on satellites can measure activity on the seafloor. It can even measure the wavelengths and height of the wave. LiDAR has the ability to measure height and ground features more accurately.
Radiometers and photometers are common instruments to determine the radiation frequency. In addition, we can use ultrasound in measuring the depth of the sea, tide and wave direction.
Furthermore, aerial photography is useful in terrain mapping. We can also create topographical maps by using this data. Earth observation satellites collect data using remote sensing. We can study the geology of a particular area by using this data.
Hyperspectral imaging is a new kind of imaging that provides pixel-level detail. It has a wide range of applications in defense intelligence and surveillance.
This technology also has a wide application in environmental balance. We can study deforestation in almost real-time. We can stop wildfires in time or at least avoid damage to the ecology.
In addition, we can scan or see ground data in real-time. This functionality is very useful in dangerous areas on the planet. In recent times this technology has wide applications in agriculture. We can use satellite imagery of crop leaves and study nutritional deficiency. Even, we can trigger necessary fertigation remotely & automatically according to the leaf color.
In conclusion, remote sensing has tremendous potential in the future. It is just the beginning.
Image Courtesy: PCI Geomatics, Clarklabs, Boeing
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