Add sar as an instrument

[TAlonglong]

I need to add sar as an instrument

[TAlonglong]

This is tricky as the sar-c has several modes with different widths and angles.

And I also dont understand what should be passed to ScanGeometry like https://github.com/pytroll/pyorbital/blob/master/pyorbital/geoloc_instrument_definitions.py#L555

ScanGeometry implemented here https://github.com/pytroll/pyorbital/blob/master/pyorbital/geoloc.py#L77

But pyorbital uses SwathBoundary implemented here https://github.com/pytroll/pytroll-schedule/blob/master/trollsched/boundary.py#L44

Or is it vice versa. I'm lost

[mraspaud]

I think it depends what you want to do. If you want to predict the footprint of the SAR pass, you need to define a ScanGeometry