Thin-client real-time interpretive object tracking system

• US 6,363,320 B1
• Filed: 08/18/2000
• Issued: 03/26/2002
• Est. Priority Date: 08/18/2000
• Status: Expired due to Term

• Current Assignee: Geospatial Technologies Incorporated
• Original Assignee: Geospatial Technologies Incorporated
• Inventors: Chou, Yue-Hong
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): NGUYEN, THU V
• Application Number:
  US09/641,302
• Time in Patent Office: 585 Days
• Field of Search: 701/200, 701/205, 701/207-209, 701/213-215, 701/225, 340/471-473, 340/935-936, 340/944, 340/988-996, 342/357.09, 342/357.1, 342/357-1-3, 342/357.17
• US Class Current: 701/207
• CPC Class Codes: B60R 25/00 Fittings or systems for preventing or indicating unauthorised use or theft of vehicles locks for vehicles E05B77/00-E05B85/00
• CPC Class Codes: B60R 25/33 of global position, e.g. by providing GPS coordinates
• CPC Class Codes: B60W 2556/50 of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments
• CPC Class Codes: G08G 1/123 indicating the position of vehicles, e.g. scheduled vehicles; Managing passenger vehicles circulating according to a fixed timetable, e.g. buses, trains, tramstransmission of navigation instructions to vehicles G08G1/0968
• CPC Class Codes: G08G 1/20 Monitoring the location of vehicles belonging to a group, e.g. fleet of vehicles, countable or determined number of vehicles
• CPC Class Codes: G08G 1/205 Indicating the location of the monitored vehicles as destination, e.g. accidents, stolen, rental

Abstract

A system for tracking objects includes a database for storing reference data as line segments corresponding to coordinate locations along environmental reference features; mobile units for connection to the objects for receiving coordinate object target point locations, and having means for receiving signals from an external location system and for generating the object data, and a wireless object data transmitter; and a computer having access to the database and to the object data, and generating an interpreted location of each of the objects in terms relative to automatically selected ones of the reference features. Also disclosed is a method for tracking the objects. Further disclosed is a computer program embodied on a computer-readable medium and having code segments for tracking objects according to the method.

Claims

1. A system for tracking objects in an environment having geographical reference features, comprising:

(a) a database for storing reference data as line segments corresponding to coordinate locations along the reference features, the database being sectioned by geographic unit, the sections comprising digital street maps;

(b) means for receiving object data including respective target points as coordinate locations of the objects;

(c) a computer having access to the database and to the object data, the computer being programmed for;

(i) generating an interpreted location of each of the objects in terms relative to automatically selected ones of the reference features;

(ii) determining geographic units containing the coordinate locations of the objects, at least some of the interpreted locations being in terms of a closest street, an intersecting street, and a direction on the closest street from the intersecting street, the determination of the closest street being qualified to exclude streets that are inconsistent with a velocity and heading of the object; and

(iii) for each of the objects, accessing a corresponding section of the database; and

(d) means for temporarily saving segments of excluded streets as reserve segments, means for determining a likelihood of abnormal object movement, and means for restoring the reserve segments as candidate segments following a determination of abnormal object movement.

2. The system of claim 1, wherein the means for receiving object data comprises a plurality of mobile units for connection to respective ones of the objects, each of the mobile units having means for receiving signals from an external location system and generating the object data, and a wireless transmitter for transmitting the object data over a wireless communication network for access by the computer.

3. The system of claim 2, wherein the means for receiving signals comprises a GPS receiver.

4. The system of claim 3, wherein the object data further includes a target altitude.

5. The system of claim 2, wherein the means for receiving signals comprises a terrestrial position receiver having access to a terrestrial location system.

6. The system of claim 2, wherein the object data further includes object identification.

7. The system of claim 2, wherein the object data further includes a target velocity.

8. The system of claim 2, wherein the object data further includes a target heading.

9. The system of claim 1, wherein at least some of the interpreted locations further comprise a closest location along the closest street.

10. The system of claim 9, wherein at least some of the interpreted locations further comprise a heading and distance from the closest location.

11. The system of claim 1, wherein at least one of the velocity and heading of the object is determined based on separately received target points of the object and a time interval between the target points.

12. The system of claim 1, wherein the means for determining abnormal object movement comprises means for determining that, for any target point, there are only reserve segments.

13. A method for tracking objects in an environment having geographical reference features in terms relative to automatically selected ones of the reference features, comprising the steps of:

(a) providing a database for storing reference data as line segments corresponding to coordinate locations along the reference features;

(b) receiving object data including a target point as a coordinate location of one of the objects;

(c) defining an initial target zone proximate the target point;

(d) determining whether a predetermined number of the line segments extend within the target zone;

(e) in the absence of the predetermined number, enlarging the target zone and repeating step (d);

(f) identifying as candidate segments the line segments extending within the target zone;

(g) selecting a matching segment from the candidate segments, qualified to exclude segments that are inconsistent with a velocity and heading of the object;

(h) calculating a matching point on the matching segment, the matching point being in closest proximity to the object location;

(i) interpreting the object location in terms of the matching segment and the matching point;

(j) temporarily saving segments of excluded streets as reserve segments;

(k) determining a likelihood of abnormal object movement; and

(l) restoring the reserve segments as candidate segments following a determination of abnormal object movement.

14. The method of claim 13, wherein the selecting of the matching segment comprises exclusion of segments from the candidate segments based on one or more of physical attributes of the reference features represented by the line segments, velocity of the object, heading of the object, a last previously identified matching segment, and previously identified location(s) of the object.

15. The method of claim 14, wherein the selecting of the matching segment further comprises determining a closest segment from remaining candidate segments.

16. The method of claim 13, further comprising determining at least one of the velocity and heading of the object based on separately received target points of the object and a time interval between the target points.

17. The method of claim 13, wherein the determination of abnormal object movement includes determining that, for any target point, there are only reserve segments.

18. The method of claim 13, further comprising determining a boundary feature from which to access the matching point, including:

(a) determining whether the matching segment terminates in an intersection, an end, and/or a continuation segment;

(b) for terminations exclusive of intersections and ends, substituting the continuation segment and repeating step (a); and

(c) including the end and intersection(s) in the interpreting of the object location.

19. The method of claim 13, further comprising:

(a) monitoring a data communication network;

(b) receiving an object location request from a client of the data communication network;

(c) automatically identifying a data output capability of the client;

(d) automatically selecting an output format for the object location interpretation, the output format being consistent with the data output capability of the client; and

(e) transmitting the location interpretation in the selected output format.

20. The method of claim 13, wherein the database is sectioned by geographic unit, the method further comprising determining geographic units containing the coordinate locations of the objects and, for each of the objects, accessing a corresponding section of the database.

21. The method of claim 13, wherein the database sections comprise digital street maps, the method further comprising determining at least some of the interpreted locations in terms of a closest street, an intersecting street, and a direction on the closest street from the intersecting street.

22. A computer program embodied on a computer-readable medium and having code segments for tracking objects in an environment having geographical reference features in terms relative to automatically selected ones of the reference features, the code segments comprising instructions for executing the steps of.

(a) providing a database for storing reference data as line segments corresponding to coordinate locations along the reference features;

(b) receiving object data including a target point as a coordinate location of one of the objects;

(c) defining an initial target zone proximate the target point;

(d) determining whether a predetermined number of the line segments extend within the target zone;

(e) in the absence of the predetermined number, enlarging the target zone and repeating step (d);

(f) identifying as candidate segments the line segments extending within the target zone;

(g) selecting a matching segment from the candidate segments, qualified to exclude segments that are inconsistent with a velocity and heading of the object;

(h) calculating a matching point on the matching segment, the matching point being in closest proximity to the object location;

(i) interpreting the object location in terms of the matching segment and the matching point;

(j) temporarily saving segments of excluded streets as reserve segments;

(k) determining a likelihood of abnormal object movement; and

(l) restoring the reserve segments as candidate segments following a determination of abnormal object movement.