Sometimes not so straight forward as those fellas make out. You want to look up the actual equtions in books.... you can do it with orthogonal measurements using linearly polarized antennas or you can make the measurement using LHCP and RHCP antennas using the appropriate mathematics. But obtain...
all depends on the antennas you use and the way you have your experiment setup. If you used unbalanced antennas the if you hold one of the receivers then you'll affect the radiation patterns and match of your antenna and therefore affect the accuracy.
GPS wise you may wise to look at what sarantel do, a nice small company in UK which do miniaturised antennas. www.sarantel.com
On that site you'll find technical papers which point out many of the pitfalls that you need to look out for. If you have bluetooth also on your board then you'll be...
I think some of what you asked for can be found in Antenna Design by Balanis, if not then that book displays a nice easy mathematically approach which you should be able to write in matlab. Using MathCAD is also very easy for postprocessing if you want to take it further
