IMO the best place to find in-depth documentation of existing technologies is the patent office. A while ago I programmed a way to locate the source of gunfire

IMO the best place to find in-depth documentation of existing technologies is the patent office. A while ago I programmed a way to locate the source of gunfire with microphones and drew a lot of inspiration from GPS patents because I couldn't find anything in-depth on the subject on Google (finding the time and position of the source of a shockwave is basically just inverse GPS multilateration)