Localization of networked mobile sensors and actuators is an active research field. One traditional approach in order to localize a mobile node has been the use of laser sensors. In some special circumstances, like a smoky environment, the use of this type of optical sensor is not a good solution. The use of radio and ultrasound signals can be used as a feasible alternative to node localization. Within the context of the EU GUARDIANS Project (Group of Unmanned Assistant Robots Deployed In Aggregative Navigation supported by Scent detection) one essential aspect is having a simple localization method of a firefighter followed by a squad of robots, that allows tracking their instant position in the space related to the base station. The authors of this paper have been developing hardware devices capable of obtaining relative positions among them and the firefighter, and have studied several networking protocols that can be useful in those situations, using wireless links provided by Wi-Fi cards of the mobile nodes, as well as the sonar sensors and radio synchronization signals.