A vehicle tracking system central host comprises a memory cache processor for managing a plurality of memory caches and a storage device linked with the memory cache processor, for receiving messages from the memory caches and writing them to a database. There are n receiver ports each for receiving message packets of an associated protocol from remote vehicle on-board tracker units. There are also n receiver processors, each associated with a port and each receiver processor being for: reading message packets received at the associated port, performing initial processing of the message packets including adding headers to provide processed messages, and writing the processed messages to a log dedicated to the receiver processor. There re also n decoders, each associated with a receiver processor log and being for (a) instantiating a service object for each log, (b) executing each service object to instantiate a message object in which data from a current message is written as attributes of the message object such that instantiation of the message object normalizes the message and the normalized fields include a vehicle identifier field, and (c) executing each service object to repeat step (b) for each successive message in the associated log, and (d) executing the service object to write each message object to one of said memory caches. The ports, the receiver processors, and the decoders operate in parallel.