This Function shall be capable of providing the following facilities:<br/><br/>(1) The ability to follow the progress of the Traveller as they move along the previously planned and requested trip and implement each part of the trip plan using the stored plan data.<br/>(2) The ability to use a variety of tracking methods to determine the actual location of the Traveller.<br/>(3) The ability to follow the time schedule in the trip plan, i.e. use a form of dead reckoning, if no suitable tracking method is available.<br/>(4) If required by the trip plan, the ability to provide detailed route guidance which it shall send to the Traveller Interface Function for output to the Traveller.<br/>(5) If the a revised version of the trip plan currently being implemented is received, the ability to stop current trip plan and commence implementing the revised one from the current location of the Traveller.<br/>(6) The ability to use a previously created trip plan to follow and provide guidance to the Traveller, even when their location moves outside the geographic area covered by the service provider that created the trip plan.<br/>
(a) continuously monitor for receipt of the trip plan for implementation data flow;<br/>(b) when the data flow in (a) is received, implement the trip plan that it contains;<br/>(c) continuously monitor for the receipt of the traveller location data flow and from its contents and the stored digital map data determine the current location of the Traveller;<br/>(d) send the result of (c) to the Monitor Trip Plan Implementation function in the traveller location data flow;<br/>(e) use the result of (c) to determine which part of the trip plan to implement;<br/>(f) if required by the trip plan load the trip guidance instructions data flow with the next instruction for the Traveller and send it to the Provide Traveller Trip Interface function;<br/>(g) whilst (c) to (f) are being implemented, continuously monitor for receipt of the implement updated trip plan data flow;<br/>(h) when the data flow in (g) is received, stop implementation of the current trip plan and wait for (a) again;<br/>(i) when the data flow containing trip plan is received, store its contents internally and continue with (c) to (f), starting from the last know location of the Traveller.<br/>
