From: Peter Hakel
Date: 2016 Sep 21, 20:37 -0700
I agree with the answers given previously, see attachments. Indeed, given the small radius of the circular LOP, the spherical trig behind the one_body_fix.xls spreadsheet is not necessary in this case - planar geometry is sufficiently accurate. And, since the position is near the equator, 1 nautical mile corresponds to 1 arc minute in longitude, not just in latitude.