Remote Sensing and GPS: Applications and Principles PDF

Okay, here is the conversion of the document and images into a structured Markdown format. ### Module - 4 **Remote Sensing** Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object, in contrast to *in situ* or on-site observat...

Okay, here is the conversion of the document and images into a structured Markdown format. ### Module - 4 **Remote Sensing** Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object, in contrast to *in situ* or on-site observation. The term is applied especially to acquiring information about the earth and other planets. This is done by sensing and recording reflected or emitted energy, and processing, analyzing, and applying that information. **Components of remote sensing:** * Energy source or illumination * Radiation and the atmosphere * Interaction with the target * Recording the energy by the sensor * Transmission, reception, and processing * Interpretation and analysis * Application **Remote sensing are two types:** 1. **Passive remote sensing** In the case of passive remote sensing, the source of energy is that naturally available such as the sun. Most of the remote sensing systems work in solar energy. 2. **Active remote sensing** In active remote sensing, the energy is generated and sent from the remote sensing platform towards the target. Most of the microwave remote sensing is done through active remote sensing. **Application of remote sensing:** 1. **Resource exploration** To study the information of sedimentary rocks and identify deposits of various minerals, detect oil identity. Underground storage of water field and identify underground storage of water. 2. **Environmental study** Use to study cloud motion and predict rains. 3. **Land use** Mapping of larger area is possible in a short time* Sight investigation * Archeological investigation * Natural hazard study **Global Positioning System (GPS)** The GPS is a satellite-based investigation system made up of a network of 24 satellites placed into orbit by the US Department of Defense. GPS was originally intended for military application, but in the 1980s the Government made the system available for civilian work. **Principles of GPS** The GPS consists of three major segments: 1. Space segment 2. Control segment 3. User segment The space and control segments are operated by US military and administrated by the US space command of the US Air Force. GPS provides specifically coded satellite signals that can be provided in a GPS receiver. Enabling the receivers to compute positions, velocity and time. 4 GPS satellite signals are used to compute position in 3 dimensions. **Application** GPS technology is now in everything from cellphones, wristwatches, to shipping containers. GPS boosts productivity across a wide growth of the economy, including farming construction, mining, surveying, package delivery, & logistical supply chain management. It is used as a tracking device. * Provide latitude, longitude, and altitude information. * Aids navigation in vehicles, aircraft, and ships. **GPS Receiver** Here's a simplified representation of the GPS receiver components: Receiving Antenna --> Low noise Amplifier --> Down convertor --> IF Amplifier --> ADC --> DSP ^ Microprocessor ^ Display **Receiving Antenna:** Recieves the satellites signals and it is mainly a circularly polarized antenna **Low noise Amplifier (LNA):** Amplifies the weak recieved signals. **Down convertor** converts the frequency of recieved signal to an intermediate frequency (IF) signal. **IF Amplifier:** Amplifies the intermediate frequency signal **ADC:** Performs the conversion of analogue signal which is obtained from IF amplifier to digital. Assume the sampling and quantization blocks are also present in ADC (Analog to Digital Convention) **DSP \(Digital Signal Processor\)**: Generates CLA codes **Microprocessor**: Performs the calculation of the position and provides the timing signals in order to control the operation of other digital blocks. It sends the useful information to display unit in order to display it on the screen. **Advantages:**