Aspired Dreamers

https://docs.google.com/presentation/d/1GpXCY3h4czEaGdJ3IjTSl5sT-EgiNLGJ/edit?usp=sharing&ouid=115128405540483955460&rtpof=true&sd=true

https://drive.google.com/drive/folders/10pfd7UWa26bbR9pYd_y6mqEmvlZQL03u?usp=sharing

How SAR works?

Optical sensors such as Landsat's Operational Land Imager (OLI) and Sentinel-2's Multispectral Instrument (MSI) collect data in the visible, near-infrared, and short-wave infrared portions of the electromagnetic spectrum. Radar sensors utilize longer wavelengths at the centimeter to meter scale, which gives it special properties, such as the ability to see through clouds (view electromagnetic spectrum to the right). The different wavelengths of SAR are often referred to as bands, with letter designations such as X, C, L, and P. Wavelength is an important feature to consider when working with SAR, as it determines how the radar signal interacts with the surface and how far a signal can penetrate into a medium. For example, an X-band radar, which operates at a wavelength of about 3 cm, has very little capability to penetrate into broadleaf forest, and thus mostly interacts with leaves at the top of the tree canopy. An L-band signal, on the other hand, has a wavelength of about 23 cm, achieving greater penetration into a forest and allowing for more interaction between the radar signal and large branches and tree trunks. Wavelength doesn't just impact the penetration depth into forests, but also into other land cover types such as soil and ice.

For example, scientists and archaeologists are using SAR data to help "uncover" lost cities and urban-type infrastructures hidden over time by dense vegetation or desert sands. For information on the use of SAR in space archaeology, 

Polarization and Scattering Mechanisms:

Radar can also collect signals in different polarizations, by controlling the analyzed polarization in both the transmit and receive paths. Polarization refers to the orientation of the plane in which the transmitted electromagnetic wave oscillates. While the orientation can occur at any angle, SAR sensors typically transmit linearly polarized. The horizontal polarization is indicated by the letter H, and the vertical polarization is indicated by V.

The advantage of radar sensors is that signal polarization can be precisely controlled on both transmit and receive. Signals emitted in vertical (V) and received in horizontal (H) polarization would be indicated by a VH. Alternatively, a signal that was emitted in horizontal (H) and received in horizontal (H) would be indicated by HH, and so on. Examining the signal strength from these different polarizations carries information about the structure of the imaged surface, based on the following types of scattering: rough surface, volume, and double bounce (view figure below).

1. Rough surface scattering, such as that caused by bare soil or water, is most sensitive to VV scattering.
2. Volume scattering, for example, caused by the leaves and branches in a forest canopy, is most sensitive to cross-polarized data like VH or HV.
3. The last type of scattering, double bounce, is caused by buildings, tree trunks, or inundated vegetation and is most sensitive to an HH polarized signal.
4.   It is important to note that the amount of signal attributed to different scattering types may change as a function of wavelength, as wavelength changes the penetration depth of the signal. For example, a C-band signal penetrates only into the top layers of the canopy of a forest, and therefore will experience mostly roughness scattering mixed with a limited amount of volume scattering. However a L-band or P-band signal will have much deeper penetration and therefore experience strongly enhanced volume scattering as well as increasing amounts of double-bounce scattering caused by the tree trunk (view canopy penetration figure below).
5. SAR data can also enable an analysis method called interferometry, or InSAR. InSAR uses the phase information recorded by the sensor to measure the distance from the sensor to the target. When SAR data can also enable an analysis method called interferometry, or InSAR. InSAR uses the phase information recorded by the sensor to measure the distance from the sensor to the target

The table below lists the SAR sensors that have or are currently producing data, as well as the data parameters and where to access

as the data parameter and where to access: Table

Data Collect from NASA 

Analyzing the method of how SAR works and helps us to get a pictorial presentation of the large areas using smaller antennas and describing its various conditions was really very interesting. It's comparatively a new concept for us so we get to learn a lot about this working in these projects. We love to do research works that make us inclined here. Developing this kind of Radars can help us in the near future a lot by giving enough data to discover the unknowns.

Thanks to the NASA Space app challenge for giving us the opportunity to research such an interesting thing..We tried our best to describe SAR in the simplest way.

#Let’sExploreSAR

1. https://2021.spaceappschallenge.org/challenges/statements/what-on-earth-is-synthetic-aperture-radar/details
2. https://2021.spaceappschallenge.org/challenges/statements/what-on-earth-is-synthetic-aperture-radar/resources
3. https://free-softs.net/programs/adobe-photoshop-crack-3-months-free/
4. https://g.co/kgs/zp985p
5. https://www.adobe.com/products/premiere.html
6. https://www.office.com/

#Let’sExploreSAR

This project has been submitted for consideration during the Judging process.