I'd like to help y'all understand the arcs because I think there is a misunderstanding of what they represent. IMHO they are not possible flight paths.
The arcs line up exactly with the range information from one single satellite, not two. This indicates that they are primarily getting their information from only one satellite (the only one in range).
Funny thing about these satellites (assuming the pic a few pages back is correct) is that they are all in a line so even if three or more were in range no "triangulation" would be possible because the satellites are not arranged in a triangle. GPS satellites are not arranged in a straight line for this exact reason.
All the arcs indicate is that at a few specific times the plane was roughly at a few points (or possibly only one point) along the arc, not that the plane flew exactly along the arc.
One satellite is going to give you a circle (in 2 dimensions, really a sphere but we can safely assume the plane is not in space or anywhere out of flight range to the west). Two satellites would give you duplicate points of intersection north and south. It would take a 3rd satellite that was not in line with the first 2 to triangulate and determine which of the north or south points was the correct one.
Since we are being shown arcs of a circle the information is only coming from one satellite.