The picture above shows the Arduino Mega Predictive Lap Timer being fed GPS RMC-Sentences from an Ardweeny pretending to be a GPS receiver. The Ardweeny is running my Scripted GPS Simulator code and is connected to a 16Mbit AT45DB161D DataFlash memory chip. This is very early beta, but here’s the basis for an Arduino Mega GPS predictive lap timer software to fiddle with.
µC eXperiment 
Hello I try the Laptimer on th Hockenheim circuit and compare the time with a transponder. I have to high difference between both sytems. I suppose that the StratLine function is the Problem. Please could you check what the Problem is ?