Ideal Remote Sensing System
The different acquisition techniques of Remote Sensing (RS) can be distinguished according to the type of the Electromagnetic Radiation used. There are remote sensing systems working with 2 types, (A) Passive Remote Sensing system, and (B) Active Remote Sensing system.
Basic components of an ideal Remote Sensing system
- A Uniform Energy Source- which provides energy over all wavelengths, at a constant, known, high level of output.
- Non-interfering Atmosphere– which will not modify either the energy transmitted from the source or emitted (or reflected) from the object in any manner.
- Unique Energy/Interactions at the Earth’s Surface– which generate reflected and/or emitted signals that are selective with respect to wave length and also unique to each object or earth surface feature type.
- A Super Sensor– which is highly sensitive to all wavelengths. A super sensor would be simple, reliable, accurate, economical, and requires no power or space. This sensor yields data on the absolute brightness (or radiance) from a scene as a function of wavelength.
- Real-Time Data Handling System– which generates the instance radiance versus wavelength response and processes into an interpre table format in real time. The data derived is unique to a particular terrain and hence provide insight into it’s physical, chemical, and biological state.
- Multiple Data Users– having knowledge in their respective disciplines and also in remote sensing data acquisition and analysis techniques. The information collected will be available to them faster and at less expense. This information will aid the users in various decision making processes and also further in implementing these decisions.
Passive Remote Sensing System
Passive Remote Sensing, source of energy is that naturally available such as the Sun. Most of the RS systems work in passive mode using solar energy as the source of EMR. Solar energy reflected by the targets at specific Wavelength bands is recorded using Sensors onboard air-borne or space-borne platforms.
Passive Remote Sensing Devices
- Hyperspectral radiometer
- Imaging radiometer
Active Remote Sensing System
In the case of Active Remote Sensing, energy is generated and sent from the RS platform towards the targets. The energy reflected from the targets are recorded using sensors onboard the RS platform. These systems actively emit Microwaves onto the surface of the Earth and then collect the amount of radiation reflected by the surface of the Earth.