초록 ▼

A system and method for determining the locations of freight containers in a freight yard is described. A remote unit that includes a GPS receiver is attached to the freight containers. The remote receivers have an independent power supply--a battery. Intermittently, either by a timer or by a motion

A system and method for determining the locations of freight containers in a freight yard is described. A remote unit that includes a GPS receiver is attached to the freight containers. The remote receivers have an independent power supply--a battery. Intermittently, either by a timer or by a motion detector, the-remote receivers are operated. Duping operation, the remote receivers receive signals from the global positioning satellite system and at an allotted time, transmit the GPS data to a base station before shutting down to conserve power. The base station processes the GPS data to determine a position in the freight yard of each freight container. When a particular freight container or contents is desired, a database in the base station can be consulted and the contents and location of a particular freight container located. The freight yard is typically outside with a view of the GPS constellation, such as a rail yard. airport baggage area, ship yard, truck park, etc. An alternative is described for use where the freight yard is a warehouse and the satellite view is obstructed. The alternative uses pseudolite or repeaters to track freight containers within the warehouse.

대표청구항 ▼

The invention claimed is: 1. A method for determining freight container locations in a freight yard comprising: attaching a number of receivers for GPS signals to a number of freight containers in said freight yard; intermittently operating each receiver to transmit an identification and position;

The invention claimed is: 1. A method for determining freight container locations in a freight yard comprising: attaching a number of receivers for GPS signals to a number of freight containers in said freight yard; intermittently operating each receiver to transmit an identification and position; receiving said identification and position at a base station; and recording the identification and position of said receivers in said freight yard. 2. The method of claim 1, including applying a correction signal to determine a more accurate position of said receivers in said freight yard. 3. The method of claim 1, said intermittently operating step including a timer which periodically initiates said transmission. 4. The method of claim 1, said intermittently operating step including a motion sensor which initiates said transmission. 5. The method of claim 1, including a database for recording the identification and position. 6. The method of claim 5, including accessing said database to determine a present position of a freight container, locating the freight container, and moving the freight container from said present position. 7. The method of claim 1, including operating one or more pseudolites in said freight yard and operating at least some of the GPS receivers to use the pseudolite signals to determine a position of a respective GPS receiver. 8. The method of claim 1, including operating a battery to power a GPS receiver. 9. The method of claim 2, wherein the correction signal is applied at the base station to the receiver positions. 10. The method of claim 2, wherein the correction signal is applied by each receiver to determine a more accurate position. 11. The method of claim 2, wherein the correction signal is a local area differential correction. 12. The method of claim 2, wherein the correction signal is a wide area correction. 13. The method of claim 2, wherein the correction signal is generated by a pseudolite. 14. The method of claim 1, wherein said intermittent operating step uses said GPS receiver to determine if said receiver position has changed, and transmits said identification and position if said receiver position has changed. 15. The method of claim 1, wherein the freight yard is an airport. 16. The method of claim 1, wherein the freight yard is an industrial yard. 17. The method of claim 5, wherein said database includes information about the inventory of a freight container. 18. The method of claim 1, wherein the freight yard is a rail yard and said containers are railcars, including the step of assembling a train based on the content of one or more railcars. 19. The method of claim 1, wherein the freight yard is a rail yard and said containers are railcars, including the step of assembling a train based on the destination for a freight container.