Paragliding task score software

Hi,

I'd like to write a small programm (online) to evaluate our paragliding competitions. We usually set a couple of turnpoints with a radius of 400 meters and the aim is to pass all these one by one and fly to the target cylinder, the finish. Just to get an idea how it looks like, I made a small graphic:

http://dl.dropbox.com/u/15535011/PGC...auswertung.png

The flights a recorded a IGC Files which i can process line by line. I need to know if the pilot exited the start cylinder before a defined time and how many cylinders were passed correct. If a cylinder was entered i have to count the distance to the previous cylinder and if not I need to chip in the edge of 90 degrees to the nearest point to the next turnpoint. I hope you understand what I mean.

Does anybody know if such a software allready exists or how to do the computation (PHP or Perl prefered). I allready found some libraries for calculatin the distance but I don't know how to do the 90 degrees calculation.

Any hints will be helpfull!

Thanks,
Max