Automated asset positioning for location and inventory tracking using multiple positioning techniques

• US 7,646,336 B2
• Filed: 03/26/2007
• Issued: 01/12/2010
• Est. Priority Date: 03/24/2006
• Status: Expired due to Fees

• Current Assignee: Mi-Jack Products Incorporated (Lanco International, Inc.)
• Original Assignee: ContainerTrac, Inc. (Lanco International, Inc.)
• Inventors: Henry, Larry, Warf, Gregory Keith, Tan, Han-Shue
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Mull; Fred H
• Application Number:
  US11/691,383
• Publication Number:
  US 20070222674A1
• Time in Patent Office: 1,023 Days
• Field of Search: 342/357.02, 342/357.07, 342/357.14, 342/457
• US Class Current: 342/357.31
• CPC Class Codes: G01S 19/485 whereby the further system is an optical system or imaging system
• 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
• CPC Class Codes: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders

Abstract

A system and method is provided for tracking and maintaining a highly accurate inventory of shipping containers that are stored within container storage facilities. The invention includes using multiple complementary real-time and post-processing positioning techniques associated with various positioning sensors that are associated with inventory pieces or equipment. Examples of such positioning techniques are DGPS, GPS with RTK, DGPS loosely-coupled with INS, DGPS tightly-coupled with INS, and DGPS deeply-coupled with INS. Data correction and fusion techniques are applied to these positioning stages to re-compute a calibrated position with an improved accuracy. An additional trajectory can be iteratively determined using the fusing technique until the position data becomes statistically trustworthy. Further, combinations of multiple real-time positioning techniques combined with past position error correction algorithms provide a high accuracy needed for inventory tracking.

Claims

1. A position tracking system comprising:

a plurality of position sensor systems on board a mobile object, each position sensor system including at least one sensor that provides signals related to a location of the mobile object and determining position data for the mobile object; and

a fusion and decision-making module configured to receive the position data from each of the position sensor systems, perform an analysis to determine the quality of each said position data by correlating the position data, set a priority for each said position data, select at least one data fusion method from a list of pre-determined data fusion methods each enabling combining the said position data in a different manner based on the determined quality and the set priority, and combine the position data using the selected at least one data fusion method to provide calibrated position data for the mobile object, whereby the calibrated position data is with a higher degree of accuracy than the position data provided by each of the position sensor systems.

2. The system of claim 1, further comprising:

a data storage unit for storing the calibrated position data provided by the fusion and decision-making module as past calibrated position data and at least part of the position data from at least one of the position sensor systems as past position data,

wherein the fusion and decision-making module further receives the past position data from the data storage unit and performs the analysis using the past position data.

3. The system of claim 2, wherein the fusion and decision-making module generates a position data and iteratively adjusts the generated position data based on the position data from the position sensor systems and the past position data from the data storage unit using mathematical formula a number of times until the generated position data is statistically trustworthy based on a predetermined criteria, and wherein the fusion and decision-making module further outputs the said generated position data as the calibrated position data.

4. The system of claim 1, wherein the position sensor systems comprise at least two of the following:

a tightly coupled DGPS/INS integration system, a loosely coupled DGPS/INS integration system, a DGPS, a dual antenna DGPS, a DGPS integrated with motion sensors, a DGPS integrated with dead reckoning sensors, an INS integrated with dead reckoning sensors, a Real Time Kinematic (RTK) DGPS, a Radio Frequency Identification (RFID)-tag-based triangulation positioning system an imaging processing-based locating system with digital map, a Real Time Locating System (RTLS) with a DGPS validation algorithm, and an RTLS and DGPS integration system.

5. The system of claim 1, wherein the fusion and decision-making module further uses information from at least one of the following, an RFID tag, a compass, a magnetometer, an altimeter, a laser, a camera, a radar, and an RF beacon transmitter, in the said analysis.

6. The system in claim 1, wherein the fusion and decision-making module further uses at least one of the following data to perform the said analysis:

(a) a digital map, (b) rules relating to an operation of the mobile object, (c) inventory information indicating a location of the mobile object, (d) an output from a sensor providing information identifying the mobile object, (e) an output from a sensor indicating the mobile object'"'"'s arrival at a specific location, and (f) an output from a sensor indicating an occurrence of a specific operation relating to the mobile object.

7. The system of claim 1, wherein the fusion and decision-making module further uses operational rules related to the position data in the analysis, the said operational rules including at least one of the following data:

identification codes, storage height, storage row number, storage isle number, surrounding environment that can cause movement blockage, a dynamic map of current inventory, and positions of nearby vehicles.

8. The system of claim 1, wherein the fusion and decision-making module further generates candidate positions and combines the generated candidate positions with the position data from each of the position sensor systems.

9. The system of claim 8, wherein the fusion and decision-making module generates the candidate positions by using filters comprising a recursive state estimation filter.

10. The system of claim 9, wherein the recursive state estimation filter comprises a Kalman filter.

11. The system of claim 1, wherein the pre-determined data fusion methods include at least one of the following:

a probabilistic data association method, a weighted summation, fuzzy logic rules, neural network, an information-based algorithm, a cognitive-based algorithm, and rule based voting.

12. A position tracking system comprising:

a plurality of position sensor systems on board a mobile object, each position sensor system including at least one sensor that provides signals related to a location of the mobile object and determining position data for the mobile object;

a fusion and decision-making module configured to receive the position data from each of the position sensor systems, perform an analysis to determine the quality of each of the said position data by correlating the position data, set a priority for each of the said position data, select a single data fusion method or a combination of data fusion methods from a list of pre-determined data fusion methods, and combine the position data using the selected at least one data fusion method to provide calibrated position data for the mobile object;

a data storage unit for storing the calibrated position data provided by the fusion and decision-making module as past calibrated position data and at least part of the position data from at least one of the position sensor systems as past position data;

an error correction module for receiving the past calibrated position data and the past position data from the data storage unit, generating trustworthy past position data, and determining errors in the past calibrated position data by comparing the past calibrated position data with the trustworthy past position data;

whereby the calibrated position data is with a higher degree of accuracy than the position data provided by each of the position sensor systems and the errors in the past calibrated position data can be corrected to further improve the position tracking accuracy.

13. The system of claim 12, wherein the fusion and decision-making module generates a position data and iteratively adjusts the generated position data based on the position data from the position sensor systems and the past position data from the data storage unit using mathematical formula a number of times until the generated position data is statistically trustworthy based on a predetermined criteria, and wherein the fusion and decision-making module further outputs the said generated position data as the calibrated position data.

14. The system of claim 12, wherein the position sensor systems comprise at least two of the following:

a tightly coupled DGPS/INS integration system, a loosely coupled DGPS/INS integration system, a DGPS, a dual antenna DGPS, a DGPS integrated with motion sensors, a DGPS integrated with dead reckoning sensors, an INS integrated with dead reckoning sensors, an RTK DGPS, an RFID-tag-based triangulation positioning system, an imaging processing-based locating system with digital map, Real Time Locating System (RTLS) with a DGPS validation algorithm, and an RTLS and DGPS integration system.

15. The system of claim 12, wherein the fusion and decision-making module further uses information from at least one of the following, an RFID tag, a compass, a magnetometer, an altimeter, a laser, a camera, a radar, and an RF beacon transmitter, in the said analysis.

16. The system in claim 12, wherein the fusion and decision-making module further uses at least one of the following data to perform the said analysis:

(a) a digital map, (b) rules relating to an operation of the mobile object, (c) inventory information indicating a location of the mobile object, (d) an output from a sensor providing information identifying the mobile object, (e) an output from a sensor indicating the mobile object'"'"'s arrival at a specific location, and (f) an output from a sensor indicating an occurrence of a specific operation relating to the mobile object.

17. The system of claim 12, wherein the fusion and decision-making module further uses operational rules related to the position data in the analysis, the said operational rules including at least one of the following data:

identification codes, storage height, storage row number, storage isle number, surrounding environment that can cause movement blockage, a dynamic map of current inventory, and positions of nearby vehicles.

18. The system of claim 12, wherein the fusion and decision-making module further generates candidate positions and combines the generated candidate positions with the position data from each of the position sensor systems.

19. The system of claim 18, wherein the fusion and decision-making module generates the candidate positions by using filters comprising a recursive state estimation filter.

20. The system of claim 12, wherein the pre-determined data fusion methods including at least one of the following:

a probabilistic data association method, a weighted summation, fuzzy logic rules, neural network, an information-based algorithm, a cognitive-based algorithm, and rule based voting.

21. The system of claim 12, wherein the error correction module provides the generated trustworthy past position data to the data storage unit to provide additional past position data.

22. The system in claim 12, wherein the error correction module further uses at least one of the following data to generate the trustworthy past position data:

(a) a digital map, (b) rules relating operation of the mobile object, (c) inventory information indicating a location of the mobile object, (d) an output from a sensor providing information identifying the mobile object, (e) an output from a sensor indicating the mobile object'"'"'s arrival at a specific location, and (f) an output from a sensor indicating an occurrence of a specific operation relating to the mobile object.

23. The system in claim 12, wherein the error correction module generates the trustworthy past position data by iteratively generating new past position data based on the past calibrated position data and the past position data from the data storage unit using mathematical formula a number of times until the generated new past position data is statistically trustworthy based on a predetermined criteria and outputting the generated past position as the trustworthy past position data.

24. A position tracking system comprising:

a plurality of position sensor systems on board a mobile object, each sensor system receiving signals from multiple sensors including a Global Positioning System (GPS) sensor and an Inertial Navigation System (INS) sensor that provide signals indicating a location of the mobile object that are used to determine position data for the mobile object, wherein the position sensor systems comprise;

a loosely-coupled GPS/INS system receiving signals from at least the GPS and INS sensors, wherein GPS data and INS data are independently provided as an output; and

a tightly-coupled GPS/INS system receiving signals from at least the GPS and INS sensors and combining the signals in an integrated manner through a Kalman filter to provide an output;

a fusion and decision-making module for receiving the position data output from each of the position sensor systems, performing an analysis to enable combining the position data outputs to provide position solution data with a higher degree of accuracy than the position data provided from a single one of the position sensor systems, and combining the data according to the analysis.

25. The system of claim 24, further comprising:

a data storage unit for storing at least part of the position data from each of the position sensor systems as past position data,

wherein the fusion and decision-making module further receives the past position data from the data storage unit and performs the analysis using the past position data.

26. The system of claim 25, wherein the fusion and decision-making module provides an output after iteratively adjusting data from the position sensor systems and the data storage unit using mathematical formula a number of times until data obtained from the mathematical formula is statistically trustworthy based on a predetermined criteria.

27. The system of claim 24, wherein the fusion and decision-making module performs filtering of the position data to provide the calibrated position data.

28. The system of claim 27, wherein the filter uses a method including at least one of the following:

a probabilistic data association method, a recursive state estimation method, fuzzy logic rules, neural network, an information-based algorithm, a cognitive-based algorithm, and rule based voting.

29. The system of claim 24, further comprising:

an error correction module, wherein the fusion and decision-making module provides the calibrated position data to the error correction module, and wherein the error correction module further receives the past position data from the data storage unit and performs an analysis to provide trustworthy past position data.