Protocol and mechanism for mutter mode communication for stationary master tracking unit

摘要

A local area network (LAN) of tracked mobile assets which are temporarily located in an area having a high density of mobile assets, such as a railway yard, employs a stationary master tracking unit that is responsible for communicating with mobile tracking units affixed to the mobile assets and transmitting information to a central station. The stationary master tracking unit may be mounted at an elevation, as on a pole, and single or multiple stationary master tracking units may exist in the same vicinity. Each stationary master tracking unit has a constant supply of power and communicates with the central station by way of either satellites or dedicated land line connection. A protocol is provided for communicating between the stationary master tracking unit and the mobile tracking units. The protocol provides a mechanism for acquiring new mobile tracking units entering the railway yard and a mechanism for releasing mobile tracking units leaving the railway yard. <IMAGE>