To localize, track and trace critical assets and first responders for remote emergency management are primary needs after a catastrophic event. In disaster areas, however, it is likely that the existing terrestrial communication network and the power grid will be cut off. Therefore, a reliable asset tracking system should be independent of those terrestrial networks, especially in terms of communication. This paper explores the development of a reliable low power local wireless communication network for portable GNSS-based positioning sensors and a centralized recording unit, as part of the independent communication network. The wireless sensors network is based on the ZigBee standard protocol and the IEEE802.15.4 compliant transceiver CC2530 from Texas Instrument. The network features low cost, low power, mesh topology, high reliability and high security.