Path following using bounded beacon-aided inertial navigation

• US 6,580,978 B1
• Filed: 04/15/2002
• Issued: 06/17/2003
• Est. Priority Date: 04/15/2002
• Status: Expired due to Fees

• Current Assignee: United Defense LP (BAE Systems Plc)
• Original Assignee: United Defense LP (BAE Systems Plc)
• Inventors: McTamaney, Louis S.
• Primary Examiner(s): Beaulieu, Yonel
• Application Number:
  US10/123,762
• Time in Patent Office: 428 Days
• Field of Search: 701/23, 701/24, 701/200, 701/206, 701/207, 701/220, 342/69, 342/357.14, 342/385, 342/386
• US Class Current: 701/23
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments
• CPC Class Codes: G01C 21/188 for accumulated errors, e.g. by coupling inertial systems with absolute positioning systems
• CPC Class Codes: G01S 13/751 wherein the responder or reflector radiates a coded signal
• CPC Class Codes: G05D 1/028 using a RF signal
• CPC Class Codes: G05D 1/0295 by at least one leading vehicle of the fleet

Abstract

A high-resolution path marking system utilized with inertial navigation systems for land vehicles. The system uses radio frequency tags or “beacons” to mark a route to be traversed by manned or unmanned follower vehicles. The RF tags serve as references to correct time and distance traveled dependent errors that accumulate in the follower vehicle'"'"'s inertial navigation system. The position of each tag is accurately encoded into its memory using a manned path marking vehicle that “proofs” the route in advance of the follower vehicles. Since the inertial navigation system for the path marking vehicle and for the follower vehicles are synchronized at the start of the route, any errors accumulated in the followers'"'"' INS with respect to the path marking vehicle are eliminated at the prescribed intervals where the RF tags are placed. The path marking vehicle can lay the route days, weeks, or even months in advance of use by the follower vehicles. Once the path is marked, it can be reused many times by the follower vehicles without further human intervention. Further, the short-range, ground based RF tags used in this method are less susceptible to jamming, and the tags are covert, i.e. the tags are small and transmit only when interrogated by a secure query signal.

Claims

1. A bounded beacon-aided inertial navigation method comprising the steps of:

a) synchronizing a navigation system of a path marker with a navigation system of at least one follower vehicle;

b) marking a path with a plurality of electronic beacons that communicate with a transceiver of said path marker;

c) calculating location coordinates for each said electronic beacon relative to said navigation system of said path marker;

d) encoding into each said electronic beacon corresponding calculated location coordinates;

e) activating sequentially said electronic beacons with a signal from said at least one follower vehicle;

f) calculating location coordinates for a detected electronic beacon relative to said at least one follower vehicle; and

g) steering said at least one follower vehicle based on said calculated location coordinates.

2. The method of claim 1 wherein:

said electronic beacons are tags that emit a radio frequency signal.

3. The method of claim 1 wherein:

said path marker is a manned vehicle.

4. The method of claim 1 wherein:

said follower vehicles are unmanned.

5. The method of claim 1 wherein:

said follower vehicles are manned.

6. The method of claim 1 wherein:

said signal from said follower vehicle is a secure signal so that said electronic beacons can be activated only by authorized users.

7. The method of claim 1 wherein:

said transceiver can determine a distance between said transceiver and said electronic beacon within a range of ±

10 cm.