From the page: Still not sure what BitScope is? BitScope is a built and tested (and previously build it yourself DIY), open design, digital storage oscilloscope and logic analyzer (also, digital sampling oscilloscope, mixed signal oscilloscope).
Using code-less acquisition techniques on the signal recorded using a sensitive receiver, they succeeded in determining the spreading code of the GIOVE-A spacecraft. Since the GPS signals are stronger, they were tracked and removed before. Analysis was don