US6360165B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for improving dead reckoning distance calculation in vehicle navigation system
Assignee: TomTom Navigation BV
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Filing: 1999-10-21
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Granted: 2002-03-19
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Expires: 2019-10-21
Abstract
Abstract The present invention enables a vehicle navigation system to automatically compensate for odometer measurement errors due to changes in tire size and/or slip, and to avoid odometer recalibration when slip is present. These capabilities improve the accuracy and reliability of the vehicle navigation system. Slip of a vehicle, e.g., a loss of traction, can occur when a road is wet or covered with snow or ice. It can occur when a road is dry, and a vehicle is accelerating or decelerating rapidly. It can occur rounding a sharp corner. Because an odometer is typically hooked up to a driven wheel, the engine or transmission, there may be large sources of error in the distance estimates derived from the odometer. Utilizing conveniently derived slip signals from an anti-lock brake system (ABS) or from a traction control system (TCS), the slip of the vehicle can be accounted for, even absent a GPS signal to recalibrate the system. This allows for improved accuracy of the system which is particularly noticeable in urban environments where GPS signals may not be available.
Inventors
- 👤 Mahesh Chowdhary
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:13
CPC Classifications
G; G01; G01C; G01C22/00; G01C22/02; G01C21/00; G01C21/26; G01C21/28
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
157 words
A method for navigating a vehicle comprising the acts of: obtaining during a first time interval an odometer indication signal indicative of a distance traveled by the vehicle, a slip indication signal indicative of the slip of the vehicle, and a heading indication signal indicative of the heading of the vehicle; converting the odometer indication signal to a first distance estimate; determining a position of the vehicle based on a known prior position, the first distance estimate obtained during said act of converting and the heading of the vehicle indications of which are obtained during said first act of obtaining; obtaining during the first time interval an external distance estimate for the vehicle from a radio navigation system; determining whether the external distance estimate includes indicia of reliability; and adjusting an odometer conversion parameter utilized in said act of converting if the external distance estimate includes indicia of reliability as determined in said second act of determining.
Claim 2
Independent Claim
157 words
A method for navigating a vehicle comprising the acts of: obtaining during a first time interval an odometer indication signal indicative of a distance traveled by the vehicle, a slip indication signal indicative of the slip of the vehicle, and a heading indication signal indicative of the heading of the vehicle; converting the odometer indication signal to a first distance estimate; determining a position of the vehicle based on a known prior position, the first distance estimate obtained during said act of converting and the heading of the vehicle indications of which are obtained during said first act of obtaining; obtaining during the first time interval an external distance estimate for the vehicle from a radio navigation system; determining whether the external distance estimate includes indicia of reliability; and adjusting an odometer conversion parameter utilized in said act of converting if the external distance estimate includes indicia of reliability as determined in said second act of determining.
Claim 3
Dependent Claim
48 words
The method for navigating a vehicle of claim 1 , further comprising the acts of: correcting an error in the position of the vehicle determined in said first act of determining if the external distance estimate includes indicia of reliability as determined in said second act of determining.
Claim 4
Dependent Claim
78 words
The method for navigating a vehicle of claim 1 , further comprising the acts of: calculating a difference between the adjusted first distance estimate and the external distance estimate; and correcting an error in the position of the vehicle determined in said first act of determining if the external distance estimate includes indicia of reliability as determined in said second act of determining and the difference as determined in said act of calculating exceeds a first threshold value.
Claim 5
Dependent Claim
32 words
The method for navigating a vehicle of claim 1 , wherein the converting act further comprises the act of: correcting the first distance estimate using data derived from the slip indication signal.
Claim 6
Dependent Claim
65 words
The method for navigating a vehicle of claim 4 , wherein the adjusting act further comprises: adjusting an odometer conversion parameter utilized in said act of converting if the external distance estimate includes indicia of reliability as determined in said second act of determining and values representative of the slip indication signal obtained in said first act of obtaining fall below a second threshold value.
Claim 7
Dependent Claim
37 words
The method for navigating a vehicle of claim 5 , wherein the odometer conversion parameter includes a constant proportionate to a ratio of a distance traveled to the number of rotations indicated by the odometer indication signal.
Claim 8
Dependent Claim
36 words
The method for navigating a vehicle of claim 6 , wherein the converting act further comprises the act of: multiplying a value representative of the odometer signal by the constant to form the first distance estimate.
Claim 9
Dependent Claim
30 words
The method for navigating a vehicle of claim 1 , wherein the radio navigation system includes a global positioning satellite sensor which generates the external distance estimate for the vehicle.
Claim 10
Dependent Claim
37 words
The method of claim 1 , wherein the first and second obtaining and determining acts, the converting and adjusting acts, are repeated a plurality of times during successive time intervals to track a movement of the vehicle.
Claim 11
Dependent Claim
44 words
The method of claim 1 , further comprising the act of: determining a slip difference between a left and a right wheel of the vehicle; and correcting the heading indication signal for the vehicle based on the slip difference calculated in said determining act.
Claim 12
Dependent Claim
161 words
A vehicle navigation system comprising: an odometer generating an odometer indication signal indicative of a distance traveled by the vehicle; a slip sensor generating a slip indication signal indicative of a slip of the vehicle; a heading sensor generating a heading indication signal indicative of the heading of the vehicle; a first logic for converting the odometer indication signal to a first distance estimate utilizing an odometer conversion parameter and for determining a position of the vehicle based on a known prior position, the first distance estimate and the heading of the vehicle indications of which are obtained from said heading sensor; a radio navigation sensor for receiving radio navigation signals; and a second logic for converting the radio navigation signals to an external distance estimate for the vehicle, for determining whether the external distance estimate includes indicia of reliability; and for adjusting the odometer conversion parameter utilized by said first logic if the external distance estimate includes indicia of reliability.
Claim 13
Dependent Claim
161 words
A vehicle navigation system comprising: an odometer generating an odometer indication signal indicative of a distance traveled by the vehicle; a slip sensor generating a slip indication signal indicative of a slip of the vehicle; a heading sensor generating a heading indication signal indicative of the heading of the vehicle; a first logic for converting the odometer indication signal to a first distance estimate utilizing an odometer conversion parameter and for determining a position of the vehicle based on a known prior position, the first distance estimate and the heading of the vehicle indications of which are obtained from said heading sensor; a radio navigation sensor for receiving radio navigation signals; and a second logic for converting the radio navigation signals to an external distance estimate for the vehicle, for determining whether the external distance estimate includes indicia of reliability; and for adjusting the odometer conversion parameter utilized by said first logic if the external distance estimate includes indicia of reliability.
Claim 14
Dependent Claim
31 words
The vehicle navigation system recited in claim 11 , wherein the first logic uses data from the slip indication signal to convert the odometer indication signal to a first distance estimate.
References Cited (Backward Citations)
US3845289A
Cited
US4139889A
Cited
US4672565A
Cited
US4608656A
Cited
US4723218A
Cited
US4570227A
Cited
US4673878A
Cited
US4611293A
Cited
US4797841A
Cited
US4796191A
Cited
US4914605A
Cited
US4734863A
Cited
US4782447A
Cited
US4751512A
Cited
US4831563A
Cited
US4862398A
Cited
US4903212A
Cited
US5040122A
Cited
US4999783A
Cited
US4984168A
Cited
US4996645A
Cited
US4964052A
Cited
US4926336A
Cited
US4937753A
Cited
US4992947A
Cited
US4989151A
Cited
US4970652A
Cited
US4982332A
Cited
US5046011A
Cited
US4918609A
Cited
JPH02107985A
Cited
US5060162A
Cited
US5067579A
Cited
US5119301A
Cited
US5287297A
Cited
US5179519A
Cited
US5148884A
Cited
US5220509A
Cited
US5177685A
Cited
US5297050A
Cited
EP0485120A2
Cited
US5486822A
Cited
US5241478A
Cited
US5283743A
Cited
US5272638A
Cited
EP0527558A1
Cited
US5293318A
Cited
US5369588A
Cited
EP0544403A1
Cited
US5434788A
Cited
US5521826A
Cited
US5323152A
Cited
EP0575943A1
Cited
US5422639A
Cited
GB2271423A
Cited
US5410485A
Cited
US5374933A
Cited
US5506774A
Cited
US5412573A
Cited
US5416712A
Cited
US5463554A
Cited
US5513110A
Cited
US5550538A
Cited
US5519619A
Cited
US5898390A
Cited
US5912635A
Cited
US5862511A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2005-03-18 | 2005-09-17 | 2006-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-03-18 | 2009-09-17 | 2010-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-03-18 | 2013-09-17 | 2014-03-19 | $7700.00 | Window Closed / Lapsed |