# FLATSIM: The ForM@Ter LArge-Scale Multi-Temporal Sentinel-1 InterferoMetry Service
## 4 Description of Products
### Auxiliary Data Package  
This set of products (Table 3) provides the user with auxiliary information common to the whole dataset, including look-up tables (LuT), LOS unit vectors, and processing parameters, etc.  
* **CosENU: LOS unit vector** The three-bands geotifi product in either radar or ground geometry gives the LOS unit vector \(\vec{u}=(u_{E},u_{N},u_{U})\), along the satellite to ground direction, such that the LOS velocity, \(V_{LOS}\), can be related to the ground velocity vector, \(\vec{V}=(V_{E},V_{N},V_{U})\), by \(V_{LOS}=V_{E}u_{E}+V_{N}u_{N}+V_{U}u_{U}\)
* **LuT: Look-up tables** The provided LuT tables allows to project 2-looks or 8-looks products in radar geometry in ground geometry and inversely.
* **TCoh: Radar backscatter properties** This product assembles at about 40 m \(\times\) 40 m resolution backscatter properties averaged over the complete data stack. It includes (1) the averaged SLC amplitude, (2) the amplitude dispersion index (\(\sigma_{A}/\overline{A}\), (3) the norm of the complex average of all successive interferogram triplets, (4) the argument of the complex average of all successive interferogram triplets.
* **Auxiliary text files**  
\begin{table}
\begin{tabular}{l l} \hline \hline
**File Type** & **Description** \\ \hline CosENU & LOS unit vector expressed in local reference frame \\  & (East, North, Up components). \\ DEM & Elevation in meter in radar geometry. Comes in two resolutions. \\ LuT & Lookup Tables used to do the mapping between radar and ground geometry. \\ TCoh & Backscatter properties in 2 looks. \\ \hline \hline \end{tabular}  
* **CosENU: LOS unit vector** The three-bands geotifi product in either radar or ground geometry gives the LOS unit vector \(\vec{u}=(u_{E},u_{N},u_{U})\), along the satellite to ground direction, such that the LOS velocity, \(V_{LOS}\), can be related to the ground velocity vector, \(\vec{V}=(V_{E},V_{N},V_{U})\), by \(V_{LOS}=V_{E}u_{E}+V_{N}u_{N}+V_{U}u_{U}\)
* **LuT: Look-up tables** The provided LuT tables allows to project 2-looks or 8-looks products in radar geometry in ground geometry and inversely.
* **TCoh: Radar backscatter properties** This product assembles at about 40 m \(\times\) 40 m resolution backscatter properties averaged over the complete data stack. It includes (1) the averaged SLC amplitude, (2) the amplitude dispersion index (\(\sigma_{A}/\overline{A}\), (3) the norm of the complex average of all successive interferogram triplets, (4) the argument of the complex average of all successive interferogram triplets.
* **Auxiliary text files**  
\end{table}
Table 3: Main auxiliary products.  
Numerous text files are added in the package for users wanting to verify some crucial processing steps. They include perpendicular baseline information, parameters for enhanced spectral diversity corrections for each sub-swath, interferogram unwrapping fractions, and interferogram phase standard deviations.  
The zipped auxiliary package is about 11 Gb for 25 processed consecutive bursts (450 km long segment). The package size will increase linearly with the number of processed bursts. The largest product sizes are for auxiliary information in 2-looks. LuT in 2-looks have a size of 2.2 Gb in ground geometry (pixel spacing of 0.000277 degree) and of 1.3 Gb in radar geometry (resolution of 30 m). They allow to geocode the wrapped 2-looks interferograms. The TCoh product is larger in ground geometry (3.9 Gb, pixel spacing of 0.000277 degree) than in radar geometry (2.6 Gb, resolution of 30 m). The LOS unit vector in 2 looks is only given in radar geometry (2.0 Gb), whereas in 8-looks it is only 186 Mb in ground geometry and 123 Mb in radar geometry.