A system for fleet management using differential GPS and VHF data transmission mobile networks

In a number of industries and services, communication with the land vehicles of the fleet has been done through VHF radio systems. This mode of operation brings into question the possibility of using this same VHF equipment to transmit and receive data for position fleet management due to this fundamental advantage. It is possible, although there are a number of limitations and disadvantages in these communication systems, mainly because of the limited propagation properties and the limited availability of channels. These problems can be reduced by means of appropriate system design and data format.