Preliminary report: Embedded platform for inertial based underwater navigation

A diver uses typically a compass, a depth gauge and a timer for underwater navigation. Especially when it comes to advanced diving in caves or wrecks, navigation and knowledge about the current position is extremely important, otherwise the diver might not find his way back to the surface and drown as soon as the breathing gas supply is finished. Other approaches are based on ultrasound transmitters that allow simple navigation tasks, however they are useless for applications like cave, wreck or long distance diving. The current paper describes a navigation platform for divers which is based on a handset with a depth sensor and a display, an inertial measurement unit incorporation gyroscopes, accelerometers and magentometers and an interface to attach different kinds of flow sensors for velocity measurement. A first prototype was developed. Additionally a buoy with an integrated GSM/GPS transmitter and a reference system for laboratory measurements can be attached. The prototype was validated in a pool and tests with the GPS reference system were carried out in the open sea.