A real time directional orientation apparatus is disclosed for use in a four pi (4.pi.) geometry. The apparatus is to be affixed to an object which translates in space. A source emitter means, which may be radioactive, is suspended in a fluid in concert with a magnet. A bank of emission detectors registers...http://www.google.co.uk/patents/US5517430?utm_source=gb-gplus-sharePatent US5517430 - Real-time digital orientation device
