The science of satellite navigation and how it can be fooled or "spoofed", a new system to pinpoint a person within a building to within a metre, and how GPS signals can probe and track volcanic dust clouds. Plus, news of what nuclear bomb tests have revealed about the brain, why volcanoes might cause Parkinsonism, HPV and oral cancer and why we comfort-eat high fat foods when we get depressed... Like this podcast? Please help us by supporting the Naked Scientists)