A portable global position and orientation estimation system for mounting on a vehicle, for operation in a passageway environment ( 502, 601), comprising: one or more odometric sensors and one or more range-sensing devices ( 301, 302) mounted on said vehicle, a microprocessor including microprocessor memory storage being connected to said one or more odometric sensors and said one or more range-sensing devices ( 301, 302), said portable global position and orientation estimation system being characterized in that said microprocessor is programmed for infrastructureless preparation of a globally consistent map by logging raw data from said one or more range-sensing devices ( 301, 302) and said one or more odometric sensors, and determines the acquisition times of all raw data as the vehicle is moved throughout said passageway environment ( 502, 601), and stores said raw data and acquisition times in said microprocessor memory storage; pre-processing said logged data to obtain estimates of the vehicle's positions and orientations during the logging process and storing said logged and pre -processed data to a log file in said microprocessor memory storage; producing the globally consistent map of said passageway environment from said logged and pre-processed data and storing said globally consistent map in said microprocessor memory storage, and said microprocessor being programmed with algorithms for repeatedly determining the global position and orientation of the vehicle, in real time, as it moves through said passageway environment ( 502, 601), using said one or more range-sensing devices ( 301, 302), said one or more odometric sensors, said microprocessor, and said globally consistent map of said passageway environment ( 502, 601) stored in said microprocessor memory storage. one or more odometric sensors and one or more range-sensing devices ( 301, 302) mounted on said vehicle, a microprocessor including microprocessor memory storage being connected to said one or more odometric sensors and said one or more range-sensing devices ( 301, 302), said portable global position and orientation estimation system being characterized in that said microprocessor is programmed for infrastructureless preparation of a globally consistent map by logging raw data from said one or more range-sensing devices ( 301, 302) and said one or more odometric sensors, and determines the acquisition times of all raw data as the vehicle is moved throughout said passageway environment ( 502, 601), and stores said raw data and acquisition times in said microprocessor memory storage; pre-processing said logged data to obtain estimates of the vehicle's positions and orientations during the logging process and storing said logged and pre -processed data to a log file in said microprocessor memory storage; producing the globally consistent map of said passageway environment from said logged and pre-processed data and storing said globally consistent map in said microprocessor memory storage, and logging raw data from said one or more range-sensing devices ( 301, 302) and said one or more odometric sensors, and determines the acquisition times of all raw data as the vehicle is moved throughout said passageway environment ( 502, 601), and stores said raw data and acquisition times in said microprocessor memory storage; pre-processing said logged data to obtain estimates of the vehicle's positions and orientations during the logging process and storing said logged and pre -processed data to a log file in said microprocessor memory storage; producing the globally consistent map of said passageway environment from said logged and pre-processed data and storing said globally consistent map in said microprocessor memory storage, and said microprocessor being programmed with algorithms for repeatedly determining the global position and orientation of the vehicle, in real time, as it moves through said passageway environment ( 502, 601), using said one or more range-sensing devices ( 301, 302), said one or more odometric sensors, said microprocessor, and said globally consistent map of said passageway environment ( 502, 601) stored in said microprocessor memory storage.