The angle in north/south direction can be converted from degrees to meters.
The angle in east/west requires you to also compensate for how close you are to a pole. At the equator, one degree represents a similar amount of meters as the north/south angle. At the north, or south pole, any measured angle will end up representing zero meters (if talking about the geoid pole and not the magnetic pole).

When you have your data as delta-x and delta-y distances, you can perform standard math operations for closest distance between a line segment P0->P1 and a point. Or closest distance between two line segments - one from measured points, and one from expected path.


Per ,If take individual points from satellite and compare it for shortest distance from a set of 200points I will miss a lot of calculations(Correct me if I am wrong). Its worth telling as I am with Silabs uC at only 45-50MIPS and a GPS receiver with 10Hz rate.
here is what I guess to do http://www.8052.com/users/apc/33455.JPG . Once the equotorial interseption matches for two datasets they are on path. But here everything looks spherical coordinate system ?


-Ap