VEHICLE NAVIGATION APPARATUS PROVIDING RAPID CORRECTION FOR EXCESSIVE ERROR IN DEAD RECKONING ESTIMATES OF VEHICLE TRAVEL DIRECTION BY DIRECT APPLICATION OF POSITION AND DIRECTION INFORMATION DERIVED FROM GPS POSITION MEASUREMENT DATA

• US 6,658,353 B2
• Filed: 11/06/2001
• Issued: 12/02/2003
• Est. Priority Date: 11/08/2000
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Tsurumi, Kiyoshi, Shimizu, Yasuhiro
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): Donnelly, Arthur D.
• Application Number:
  US09/985,765
• Publication Number:
  US 20020055819A1
• Time in Patent Office: 756 Days
• Field of Search: 701/214, 701/200, 701/205, 701/207, 701/210, 701/213, 701/215, 340/988, 731/78.R, 342/358, 342/457
• US Class Current: 701/214
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments

Abstract

In a vehicle navigation apparatus having a control section which calculates relative vehicle positions and travel direction by dead reckoning calculations based on outputs from on-board sensors and periodically acquires GPS measurement data via a GPS receiver and applies error-reduction filter processing to these data to obtain position and travel direction information for correcting the calculated relative positions, the apparatus has a function for detecting that a travel direction obtained by dead reckoning contains an excessive error, and when that condition is detected, for directly applying an estimated vehicle position and travel direction derived directly from the GPS data, without filter processing, to correct the corresponding relative position and travel direction estimates. Rapid correction can thereby be achieved when the vehicle has been operated in a condition whereby a large amount of error has suddenly arisen in the travel direction that is estimated by the apparatus through dead reckoning calculation, e.g., after the vehicle has been rotated on a turntable with the vehicle navigation apparatus inoperative.

Claims

1. A vehicle navigation apparatus comprising:

sensor means for producing signals indicative of amounts of change in heading direction of a vehicle and amounts of change in distance traveled by said vehicle;

current position calculation means for calculating successive current positions and travel directions of said vehicle based on said signals produced from said sensor means, said current position calculation means including Global Positioning Satellite (GPS) receiving means for receiving GPS system radio waves and for thereby deriving position measurement data relating to said vehicle, means for applying predetermined filter processing to said position measurement data, and GPS correction means for periodically applying data resulting from said filter processing to correct respective errors in said current positions and travel directions which are calculated by said current position calculation means to obtain corrected current positions and travel directions;

means for registering as a reference position a specific position which is estimated by said apparatus as having been attained by said vehicle, and wherein said means for registering said reference position comprises means for detecting that said vehicle has executed a plurality of successive complete turns, and wherein an estimated current position of said vehicle which is derived by said vehicle navigation apparatus upon completion of said turns is determined as said reference position; and

error judgement means for judging a deviation which is indicative of at least one of said respective errors in said current positions and travel directions, to determine whether or not said deviation exceeds a predetermined amount, said deviation being judged based on relative positions, with respect to said reference position, of a first position which is an estimated position of said vehicle calculated from said position measurement data and a second position which is an estimated position of said vehicle calculated by said current position calculation means substantially concurrently with said calculation of said first position; and

wherein said GPS correction means is adapted to directly apply said position measurement data to correct said respective errors in said current positions and travel directions to thereby obtain said corrected current positions and travel directions, without application of said filter processing, when it is judged by said error judgement means that said predetermined amount is exceeded.

5. A vehicle navigation apparatus as claimed in claim 1, wherein said respective processing, calculation and judgement means of said apparatus are implemented by a computer system operating under control of a program which is stored on a readable data storage medium.

2. A vehicle navigation apparatus comprising:

sensor means for producing signals indicative of amounts of change in heading direction of a vehicle and amounts of change in distance traveled by said vehicle;

current position calculation means for calculating successive current positions and travel directions of said vehicle based on said signals produced from said sensor means, said current position calculation means including Global Positioning Satellite (GPS) receiving means for receiving GPS system radio waves and for thereby deriving position measurement data relating to said vehicle, means for applying predetermined filter processing to said position measurement data, and GPS correction means for periodically applying data resulting from said filter processing to correct respective errors in said current positions and travel directions which are calculated by said current position calculation means to obtain corrected current positions and travel directions;

error judgement means for judging a deviation which is indicative of at least one of said respective errors in said current positions and travel directions, to determine whether or not said deviation exceeds a predetermined amount, wherein said GPS correction means is adapted to directly apply said position measurement data to correct said respective errors in said current positions and travel directions to thereby obtain said corrected current positions and travel directions, without application of said filter processing, when it is judged by said error judgement means that said predetermined amount is exceeded;

map data storage means for storing and providing map data including road map data;

means for estimating a travel path which has been traversed by said vehicle up to an estimated current position of said vehicle, based on said corrected current positions and travel directions; and

means for periodically performing a map matching processing operation, to compare said travel path with said road map data and apply correction for a residual error in said corrected current positions, based on results of said comparison, to obtain a final corrected current position of said vehicle.

3. A vehicle navigation apparatus as claimed in claim 2, further comprising;

display means; and

means for reading out, from said map data storage means, road map data corresponding to a region in which said vehicle is currently located and supplying said road map data together with data expressing said final corrected current position, to thereby produce a display of a road map of said region with said final corrected current position visibly distinguished therein.

4. A vehicle navigation apparatus as claimed in claim 2, further comprising means for providing a guidance function comprising:

means operable for externally inputting data indicative of a required destination of said vehicle;

means for calculating an optimum route extending from said final estimated current position of said vehicle to said destination;

display means; and

means for reading out from said map data storage means road map data corresponding to a region containing said optimum route and supplying said road map data to said display means together with data expressing said final corrected current position and said optimum route, for thereby producing a display indicative of a relationship between said final estimated current position and said optimum route.

6. A vehicle navigation apparatus comprising:

sensors for detecting changes in a vehicle heading direction and in vehicle distance traveled and for producing change signals representative of the changes in the vehicle heading direction and in the vehicle distance traveled;

a Global Positioning Satellite (GPS) receiver for receiving GPS signals and for deriving vehicle position measurement data from the GPS signals; and

a navigation controller for periodically calculating current vehicle position and vehicle travel direction based on the change signals produced by the sensors, for registering a vehicle attained position as a reference position, for detecting a plurality of successive vehicle turns, for deriving the reference position based on the plurality of successive turns, for determining if a deviation indicative of at least one of a plurality of respective errors in the current vehicle position and the vehicle travel direction exceeds a predetermined amount based on relative positions of a first estimated position and a second estimated position with respect to the reference position, the first estimated position being based on the position measurement data and the second estimated position being based on the current vehicle position and the vehicle travel direction, and for determining a corrected current vehicle position and a corrected vehicle travel direction,

wherein the navigation controller is further for applying predetermined filter processing to the vehicle position measurement data derived by the OPS receiver and for applying data resulting from the filter processing to correct respective errors in the current vehicle position and vehicle travel direction to determine the corrected current vehicle position and the corrected vehicle travel direction when the deviation does not exceed the predetermined amount, and

wherein the navigation controller is for applying position measurement data to correct the respective errors to thereby obtain the corrected current vehicle position and vehicle travel direction when the deviation exceeds the predetermined amount.

7. A vehicle navigation apparatus comprising:

sensors for detecting changes in a vehicle heading direction and in vehicle distance traveled and for producing change signals representative of the changes in the vehicle heading direction and in the vehicle distance traveled;

a Global Positioning Satellite (GPS) receiver for receiving GPS signals and for deriving vehicle position measurement data from the GPS signals;

a map data input for storing and providing map data including road map data; and

a navigation controller for periodically calculating current vehicle position and vehicle travel direction based on the change signals produced by the sensors, for determining if a deviation indicative of at least one of a plurality of respective errors in the current vehicle position and the vehicle travel direction exceeds a predetermined amount, for determining a corrected current vehicle position and a corrected vehicle travel direction, for estimating a vehicle travel path based on the corrected current vehicle position and vehicle travel direction, and for periodically performing a comparison between the vehicle travel path with the road map data to correct residual errors in the corrected current vehicle position based on results of the comparison to obtain a final corrected current vehicle position, vehicle travel direction to determine the corrected current vehicle position and the corrected vehicle travel direction when the deviation does not exceed the predetermined amount, and

wherein the navigation controller is for applying position measurement data to correct the respective errors to thereby obtain the corrected current vehicle position and vehicle travel direction when the deviation exceeds the predetermined amount.

8. The vehicle navigation apparatus of claim 7, further comprising a display device,

wherein the navigation controller is further for reading road map data from the map data storage data corresponding to a current vehicle location region and is for supplying the road map data and the final corrected current vehicle position to the display device.