PyAPS grib file timing

Possible PyAPS improvement?

We have this time string in the .unw header file : date: 2015 1 25 8 28 59.6906

At the moment, we just have the 12noon weather file for APS correction.

We should try to correct with a .grib, the weather file, close to this time. .grib files are available every 6 hours?

Any other source of weather file, or some other preferred way?

[neginmoghaddam]

@basaks : a simple description for lv_theta with a schematic lv_theta is SAR look-vector elevation angle at each map pixel. The values in lv_theta changes between -pi/2 (down) and pi/2 (up). This vector defines as the angle between the horizontal surface and the look vector with positive angles indicating sensor positions above the surface.

[mcgarth]

Good pick up! PyAPS is after the angle labelled as ‘Elevation Angle’ in @neginmoghaddam’s diagram. A conversion (i.e. pi/2 minus lv_theta) needs to be undertaken by the prepifg code when the data is read in. Possible conversion to degrees also.