GRASS Users,
I'm a new GRASS (and GIS) user working out how to geo-register data taken from
an airborne SAR. I have the lat/lon of the SAR entenna, the depression angle
(it's a side-looking SAR), and the range in meters from the antenna to the
center of the n x m patch of ground data is being collected on. I need to find
the lat/lon of the center of that patch to 1 meter accuracy, if possible. It's
easy to determine what the horizontal distance is given the depression angle and
range. What I'm not sure about is how do I use that distance (I also know the
compass direction) to find the patch center's lat/lon?
Some things I've thought of trying are learning what the Earth's circumference
is at that latitude (46.392218) and dividing by deg, min, sec, sec fraction to
find the distance-to-degrees conversion. But I'm unsure what kind of error this
would introduce for the area I'm interested in (South Eastern Washington state).
Any suggestions would be greatly appreciated,
Marie Vorce