VIA Technologies EPIA SN-Series Specifications download pdf (Page 63)

FASTER Planning Software

Figure 44: FASTER flight planner - computed flight height [m]

To use the ASTER DEM database the DEM_extraction.m script has been created. It

takes as input the DEM area coordinates generated by the FASTER_planner.m script.

Longitude and latitude boundaries are evaluated in order to determine if all the DEM

area corners belong to the same tile. Then tile file name is reconstructed using the

ASTGTM_ prefix adding the coordinates already found. Once the file name is built the

corresponding ZIP file is extracted and the GeoTIFF image is imported in the Matlab

workspace using the geotiffread.m script (data is then converted to “double”). Each tile is

managed as a 3601x3601 array (the first row and the last column overlap the adjacent

tiles). Then the DEM area is searched inside the array and the highest value is selected as

the highest obstacle in the 3000 m range expected by the aeronautical regulation. In the

previous example a 215x155 subset matrix of the ASTGTM_N44E011 tile was used. The

flying altitude is stored and the procedure continues with the successive step.

At this time optical parameters are necessary to compute the image sensor projection

on the ground, using equations 1 to 5. A database of possible sensor solutions was created

in which is possible, selecting a particular instrument, to retrieve corresponding values for

the optical parameters. The database is accessed via the FASTER_geometry.m script

where Matlab structures are used to store information. Acquisition sensors can be coupled

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VIA Technologies EPIA SN-Series Specifications Page 63