In the context of a diploma thesis at the Zurich University of Applied Sciences, we developed a radio-based search/localization system. The terminal devices (agents) are able to transmit GPS positioning information, but also to transmit and receive arbitrary data over the radio network. In order to accomplish this goal, a routing- and transport protocol was developed, over which even in an ever-changing and dynamic network a bidirectional communication would be possible. Furthermore, an easy-to-use webinterface was developed, where customers may query the last positions of their agents and send them messages. The product as a prototype with all its components has been developed and created in eight weeks in the context of a feasibility study.

The main problem and core of this thesis was, that agents should be able to maintain a bidirectional communication with the basestation even if they are out of range of the basestation! Thus, the packets will be routed on the shortest way possible on a hop-by-hop basis over other agents, until a basestation is reached.