The main question is about how optical remote sensing can be implemented to investigate the HH370 debris. The perfect understanding of the principles of remote sensing and optical satellite data can assist to answer this question. This chapter aims at reviewing the fundamental of optical remote sensing satellite data. From the point view of the electromagnetic spectrum to physical characteristics of optical satellite sensors with high and low resolution, the MH370 debris can be recognized in satellite images. In this understanding, the chapter carries a novel explanation of remote sensing technology of MH370 as a specific and unique case. This clarification is deliberated with particular debris imagined in satellite images as quantum information, which is presented somewhere in the Indian Ocean.
TopElectromagnetic Spectrum
The electromagnetic spectrum definitely refers to the wavelengths of light. In this regard, the electromagnetic spectrum is the time period used to describe the all-inclusive range of light that is existent. Conversely, most of the light in a universe from radio waves to gamma rays is vague to us!
Light is a wave of irregular electric and magnetic fields. The transmission of light is not much exceptional than wave propagation in an ocean. A vital descriptive characteristic of a waveform is its wavelength or distance between succeeding peaks or troughs. In remote sensing, the wavelength is most frequently measured in micrometres, each of which equals one-millionth of a meter. The variation in the wavelength of electromagnetic radiation is so significant that it is usually proven on a logarithmic scale (Figure 1) (Lillesand et al., 2007 and Bakshi and Godse, 2009).
Figure 1. Electromagnetic wave spectra
Physically, the Earth is brightened through electromagnetic radiation from the Sun. The peak solar power is in the wavelength variation of visible light (between 0.4 and 0.7 µm) (Figure 1). Additional large components of incoming solar energy are in the configuration of invisible ultraviolet and infrared radiation. Merely tiny portions of solar radiation encompass the microwave spectrum. Imaging radar systems used in remote sensing create and transmit microwaves, and then measure the component of the signal that has backscattered to the antenna from the Earth’s surface (Lillesand et al., 2007).
The electromagnetic spectrum ordinarily breaks up into seven regions, in order of decreasing wavelength and growing energy and frequency: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays.
Radio Waves
Radio waves are at the lower range of the EM spectrum, with frequencies of up to about 30 billion hertz, or 30 gigahertz (GHz). These correspond to the wavelengths as low as 30 cm and as high as 1000 m. Radio waves are used specifically for communications, including voice, data and leisure media (See Chapter 5).
For instance, a radio programme receiver does not require to be absolutely in the outlook of the transmitter to obtain the signals. Diffraction, however, allows low-frequency radio waves to be received behind the hills, in spite of repeater stations are often used to improve the quality of the signals. The lowest frequency radio waves are also reflected from an electrically charged layer of the upper atmosphere, called the ionosphere. This means that they can still reach receivers that are not in the line of sight because of the curvature of the Earth's surface (Figure 2).
Figure 2. Radio wave reflection from the ionosphere