[Physics Class Notes] on Remote Sensing Pdf for Exam

What is Remote Sensing?

The word “remote sensing” was initially used in the 1950s in the USA by Ms. Evelyn Pruitt worked for the U.S. Office of Naval Research.

Remote sensing technology is used to summon information and understanding about an object while dealing with any physical contact.

This is a modern technology that started when the camera was invented for the first time. Did you know that the idea of taking the still photographs of Earth for the objective of topographic mapping surfaced in the middle of the 1840s?

At the time of World War 1, cameras were used on aero-planes to avail the best aerial view of lands which initiates an insurgency in military science. Satellite remote sensing was improved during the earlier space age.

These cameras were used for viewing Earth’s surfaces, for supplying the vivid details about Earth’s forests, lands, lakes, rivers, mountains, etc. for mapping.

Remote Sensing Explained

As we studied earlier, remote sensing is science-filled with technology that helps to gather data and to analyze a body without making any kind of physical contact.

This technology is vastly used in sectors like hydrology, geography, ecology, glaciology, oceanology, geology.

A tool known as the geographic information system is utilized for analyzing and mapping the Earth’s feature events. The GIS technology and remote sensing collect significant database operations, such as statistical analysis and query, through the map.

The GIS conducts to collect information on different locations and aids tools for displaying and analyzing for the calculations of population, economic development, its characteristics, and undergrowth.

All these functions build GIS separate from other systems and establish it for the wide range use of private and public remote sensing applications. These applications are for planning and forecasting outcomes generated from remote sensing satellites.

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Fundamentals of Remote Sensing

As we know all about remote sensing, let’s discuss its fundamentals. A remote sensing system works with the help of a detector for sensing the reflected or emitted energy from the surface of the Earth. It may be modified by the interposing atmosphere.

The sensor is available on a drone, satellite, or aircraft. The sensor converts the energy into a voltage form. This sensor is an analog to digital converter changes to a single integer value (known as Digital Number, or DN) for the energy.

• The DN can be stored directly with the help of a digital detector. Only then can we display this value with an exact color to create an image of that region sensed by the system.

• The DN defines the energy sensed with the help of a sensor in a particular part of the emitted or reflected from a particular region of that electromagnetic spectrum.

Sonar imagery also applies these principles, most helpful in the water where sound barges readily, whereas electromagnetic energy breaks quickly.

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Types of Sensors in Remote Sensing

The remote sensing can be differentiated into two types, they are:

Those who put their source of energy (a large “flashbulb”) are called an active system.

Those who use solar energy emitted by the surface or reflected from the surface

Four things are being considered for satellite resolution, such as radiometric, spectral, spatial, and temporal resolution.

In a remote sensing system, electromagnetic radiation and the atmosphere controls many things. The characteristics of the imagery can be easily determined by satellite orbits.

The photo shows what satellite sees and how many times it returns to its original position.

The important design of remote sensing systems is the signal to noise ratio.

The following points are some essential elements for remote sensing;

What is Remote Sensing Satellite?

The technology is dependent on detecting and analyzing the physical phenomenon of an area by calculating its emitted or reflected radiation at a distance from satellite or aircraft.

Some enhanced cameras are specialized for sensing images, which offer clarity about the Earth to the researchers. 

Some of the Examples Are

• Satellites and planes are using the best cameras to capture images of large areas on the surface of Earth. It allows researchers to visualize even better than standing upon the ground.

• Sonar systems available on ships can be used to capture images of the ocean floor without traveling to its bottom.

• Satellites’ cameras can be used to create images of temperature differences in the ocean.