Remote sensing

Remote sensing 

Remote sensing is the process of receiving information about any object without making any physical contact. It is a technology through which the properties of any area, object, or phenomenon can be identified, calculated and then analyzed. This method is generally used in land mapping, forecasting weather, studying natural hazards, coloring resources, etc. The data from this method is stored and altered through computers with the help of software like ERDAS Imagine, ESRI, and ERMapper. Therefore, remote sensing can be defined as the science of obtaining information about any phenomenon or object, or area by calculating the emitted and reflected radiations. Let’s discuss this further in detail below. 

• Types Of Remote Sensing 

There are various types of remote sensing. Each of them is used for different analyses. For example, some can cover only short areas, while some are great options to observe and scan a larger area. But the most commonly used remote sensing are radar and lasers. 

• Radar

Radar is one of the types of remote sensing used in safety concerned tasks. The best use of it is detecting weather and measuring air traffic control. Radar remote sensing helps the weather analysts forecast the weather and helps conclude if there is any storm arriving. Doppler Radar is a type of radar used to collect meteorological information and monitor the traffic and speed of the vehicles. 

• Lasers

Laser is another type of remote sensing. This type of remote sensing is used in satellites to measure and calculate wind speed, ocean currents, and direction. Under this, Altimeters are used to measure seafloor mapping as they can penetrate a large mass of water. It helps measure the heights of the ocean or the ocean’s depth to make seafloor mappings. LIDAR, Light Detection and Ranging are some types of laser remote sensing. It is used to find out the distance with the help of light reflections and is widely used in weapons. It is also capable of measuring the chemical contents in the atmosphere. 

• Optical 

Optical remote sensing is a type of remote sensing that makes use of visible near the short wave infrared and infrared sensors to make images on the earth’s surface with the help of solar radiation reflected from the area on the ground. Under this type, the different surfaces reflect and absorb the light in different types. 

• Infrared 

Infrared remote sensing is a type of remote sensing that uses infrared sensors to detect radiation from the earth’s surface. The thermal infrared region includes the long wave infrared(LWIR) and Middle Wave Infrared(MWIR). These radiations are emitted from any warmer object. These sensors are installed in satellites to measure the land and sea surface of the earth. Along with that, it is also used in detecting forest fires. 

1. Microwave 

Microwave remote sensing uses electromagnetic radiation having a wavelength between 1cm to 1m. These microwaves sensors produce radio signals in the bandwidth of the microwave and then observe which part of it is scattering from the target to the sensor. 

• Satellite

Satellite remote sensing is a method of detecting and then analyzing the characteristics of a particular area or an object by calculating and measuring the reflected radiations from an aircraft or a satellite. 

• Airborne 

Airborne remote sensing is a sensor placed on aircraft to click images of earth from space. One of the best parts about this method is that it gives high-resolution pictures compared to the images captured by the satellites. 

• Principles of remote sensing

Different objects produce different energy in different bands of the electromagnetic spectrum. It depends on the material’s properties, whether it is physical, structural, or chemical, the roughness of the surface, and the wavelength of the radiant energy. 

• Active and passive remote sensing

Active remote sensing operates under their source of light. Every active sensor in the remote sensing forwards its signal to the given object and confirms the response. The devices use microwaves because they are used to the weather conditions. Active remote sensing transmits lights while measuring distance, atmospheric conditions and scenarios, height, and more.

 While passive remote sensing does not use its energy to analyze and search the surface or any object as it was in the case of active sensors. Passive sensing is mainly dependent on the natural source of energy from the sun, which is thrown back by the object or surface. Therefore it can only be used when there is the presence of proper sunlight, that is, during the daytime.

Conclusion 

Here is a detailed discussion about remote sensing. Above is the detailed guide on remote sensing, types of remote sensing and active and passive remote sensing.