Automatic past error corrections for location and inventory tracking

• US 20070010940A1
• Filed: 06/29/2006
• Published: 01/11/2007
• Est. Priority Date: 07/05/2005
• Status: Active Grant

• Current Assignee: Mi-Jack Products Incorporated (Lanco International, Inc.)
• Original Assignee: ContainerTrac, Inc. (Lanco International, Inc.)
• Inventors: Tan, Han-Shue, Henry, Larry
• Granted Patent: US 7,848,881 B2
• Time in Patent Office: Days
• US Class Current: 701/207
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01S 19/39 the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
• CPC Class Codes: G01S 19/393 Trajectory determination or predictive tracking, e.g. Kalman filtering
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled
• CPC Class Codes: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management

Abstract

A system is provided for tracking and maintaining an inventory of location of containers that are stored on cargo ships or in a container yard. The system includes one or more sensors, such as GPS and INS sensors for obtaining real-time position information, as well as a processor configured to automatically provide post processing to recover lost data and to correct erroneous data, such as when real-time position signals are blocked or distorted, the post processing performed by estimating trajectories and correcting the location errors. Post-processed positioning techniques are continuously applied to the stored position data to iteratively determine calibrated position locations to provide calibrated second trajectory segments in a real-time fashion. The calibrated second trajectories are then used to identify the errors in the past real-time position data as soon as a segment of the second calibrated trajectory becomes statistically trustworthy. Corrections can be automatically made in inventory locations stored in a database to correct position errors for the containers.

Claims

1. A position tracking system comprising:

a positioning unit associated with a mobile object for providing first position data of the mobile object enabling providing a first real time trajectory indicating movement of the object;

a data storage unit for storing the first position data;

a navigation processing module for generating calibrated second trajectory data from the first position data; and

an error correction computation module for comparing the second calibrated trajectory data from the navigation processing module with the first trajectory data and generating correction data indicating corrections in the first position data.

2. The system of claim 1, further comprising a reporting module connected to the error correcting module for providing messages indicating a location of data errors in the first position error as stored in the data storage unit.

3. The system of claim 1, wherein the positioning unit comprises:

a first position sensor for providing real-time position data of the mobile object for determination of the first position data; and

a second sensor providing at least one of the following information that supports determination of the first trajectory of the mobile object;

linear motion data, angular motion data, linear velocity data, angular velocity data, linear acceleration data, and angular acceleration data.

4. The system of claim 3, wherein,

the first position sensor includes a Global Positioning System (GPS) receiver;

and

the second sensor includes at least one component from an Inertial Navigation System (INS).

5. The system of claim 1,

wherein the positioning unit includes at least one senor for providing the first real-time position data and a processor that determines the first trajectory;

and

wherein the navigation module uses at least one output from the positioning unit to generate the second trajectory data from the first real-time position data using an algorithm for filtering the stored first position data to provide at least a segment of the second trajectory with more accuracy than the first trajectory.

6. The system in claim 1, wherein the navigation module generates an adjustable segment of the second trajectory by iteratively calibrating the second trajectory using mathematical formula a number of times until the segment is statistically trustworthy based on a predetermined standard.

7. The system in claim 1, wherein the error correction computation module updates the first position data with the corrected data by storing the corrected data in place of some of the first position data in the data storage unit.

8. The system in claim 1, wherein the error correction computation module updates the first position data with the corrected data to provide second position data and stores the second position data in the data storage unit.

9. The system in claim 1, wherein the error correction computation module reports the corrected data to a user interface.

10. The system in claim 1, wherein the positioning unit comprises:

sensors for receiving position data; and

a digital map for correlating with the position data from the sensors to provide the first position data and the first real time trajectory.

11. The system of claim 1,

wherein the positioning unit resides in the mobile object, and

wherein the navigation processing module and the error correction computation module reside away from the mobile object and are wirelessly linked to the positioning unit.

12. The system of claim 1,

wherein the positioning unit and the navigation processing module resides in the mobile object, and

wherein error correction computation module resides away from the mobile object and is wirelessly linked to the positioning unit and the navigation processing module.

13. The system of claim 1,

wherein the positioning unit, the navigation processing module and the error correction computation module reside in the mobile object.

14. A method for providing position data for a mobile object comprising the steps of:

obtaining first position data of the mobile object in a real-time fashion;

storing the first position data in at least one timed sequence;

determining a first trajectory based in part on the first position data;

calculating the position data motion of the mobile object by employing a post-processing estimation filter to provide a second trajectory more accurately depicting movement of the object than the first trajectory;

correlating the first trajectory with the second trajectory to identify segments of the first position data that require correction; and

generating correction data indicating corrections in the first position data.

15. A resource tracking inventory system comprising a processor with a readable storage medium, the storage medium storing inventory data to enable tracking of a mobile object by the processor, the storage medium:

storing first position data of the mobile object in at least one timed sequence;

storing a first trajectory indicating movement of the mobile object based in part on the first position data;

storing a second trajectory indicating movement of the mobile object, the second trajectory obtained from the first position data using a filter including post-processing estimation algorithms so that the second trajectory is more accurately predicts movement of the object than the first trajectory; and

storing revised position data indicating revisions to the first position data based on a comparison of the first trajectory with the second trajectory.

16. The system in claim 15,

wherein the storage medium further stores event data of the mobile object in a database, and

wherein the processor further revising the event data by retracing the event sequence based on the revised position data of the mobile object.