Space radar monitoring

Project's objective

Radar monitoring and creation of models of displacement and deformation of the earth's surface and structures on the territory of the Customer based on satellite images from COSMO-SkyMed-1-4 satellites

Work description

Purchase and delivery to the customer of archival materials of 25 repeated space radar surveys from the COSMO-SkyMed-1-4 satellites, obtained over 3 years, of the territory in accordance with the technical specification.

1. Space imagery must meet the following conditions:

• terrain resolution 3 meters;
• polarization HH;
• processing level L1A;
• radiometric resolution 32 bit;
• international coordinate system WGS-84;
• formats for transmitting space imagery materials: in the international coordinate system WGS-84 in * h5 format and geocoded amplitude images in geotiff format.

2.In order to ensure optimization of work on interferometric processing of space radar imagery materials when selecting space images from CosmoSkyMed-1-4 satellites, the following criteria should be taken into account from the general archive to the customer's territory:

• Absolute values ​​of perpendicular baselines;
• Minimum standard deviation of values ​​of perpendicular baselines;
• Equality of time intervals between adjacent surveys;
• The maximum possible overlap area of ​​the selected images;
• If the archive series contains images with orbit correction files of different accuracy (preference is given to images generated using exact orbit files).

3. Interferometric processing of materials from space radar surveys of the Customer's territory is carried out in order to create models of displacements and deformations of the earth's surface and structures that have occurred over three years. Processing was performed in a software package and includes the following stages:

1. Selection of the main image from 25 repeated space images of the territory, to which the rest of the space images from the remaining 24 space images will be registered (hereinafter referred to as auxiliary images);

2. Combination (registration) of the main and auxiliary radar images of the interferometric series (in automatic mode);

3. Generation of interferograms, which are the result of complex element-wise multiplication of the main image and auxiliary images of the interferometric series, geometrically aligned with each other;

4. Separation of the topographic and deformation components of the interferometric phase due to the synthesis of the relief phase using the available publicly available digital terrain model SRTM, resulting in differential interferograms;

5. Calculation of coherence files for the overlap area of ​​each of the pairs of radar images that make up the interferometric pair, in values ​​from 0 to 1 for each pair of corresponding pixels;

6. Phase sweep (procedure of transition from relative phase values ​​to absolute values) for applying atmospheric filters;

7. Selection of points - candidates for permanent radar signal scatterers;

8. Final selection of permanent scatterers from candidate points, taking into account a number of selection criteria;

9. Calculation of displacements as of each shooting date relative to the first in the order of shooting for each permanent scatterer.

10. Creation of a model of displacements and deformations of the earth's surface and structures that occurred during the observation period on the site of the Customer's territory in the form of a vector file of points - permanent scatterers of the radar signal, in the attributes of each of which - point displacements as of each shooting date relative to the date of the first survey, in * shp and * kmz formats.
11. Formation of the technical report based on the results of the work in electronic form and on paper.

Results

The customer received a report with the results of interferometric data processing from the COSMO-SkyMed satellites, including an analysis of the revealed displacements and deformations of the earth's surface and structures that occurred during the observation period.