Method and apparatus for applying decimation processing to vehicle position data based upon data accuracy estimation

• US 6,480,784 B2
• Filed: 03/20/2001
• Issued: 11/12/2002
• Est. Priority Date: 09/24/1999
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Mizuno, Masaru
• Primary Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US09/811,412
• Publication Number:
  US 20010018636A1
• Time in Patent Office: 602 Days
• Field of Search: 701/207, 701/213, 701/214, 701/35, 701/24, 701/25, 701/210, 342/352, 342/357.01, 342/357.02, 342/357.08
• US Class Current: 701/207
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network

Abstract

A method and apparatus for use with a mobile body navigation system are provided for reducing an amount of position data, expressing successive positions along a route that has been traversed by a mobile body, which are recorded by a data recording section to subsequently provide a route display or are transmitted by radio by a data transmitting section. A position recording judgement section uses one or more judgement criteria to obtain an indication of the degree of accuracy of each of the vehicle positions that are calculated by the navigation system, and enables recording or transmission of only those data that express positions for which the judgement criteria indicate that the corresponding degree of accuracy is sufficiently high.

Claims

1. A position data decimation apparatus for use in a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position recording means for recording data expressing a plurality of said positions, wherein said position data decimation apparatus comprises:

position accuracy indication means for generating, in conjunction with each of said calculated positions, corresponding indication information relating to a positioning accuracy of said calculated position; and

position accuracy judgment means for selecting data expressing specific ones of said positions, to be recorded by said position recording means, with said selection based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating said positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites, and relative position sensing means for periodically calculating said positions of the mobile body as relative positions at times between successive calculations of said absolute positions, and wherein said position accuracy indication means comprises means for calculating, for each of said relative positions, as said indication information;

an absolute positioning error of an absolute position which precedes said relative position, a relative positioning error of said relative position, and

the sum of said absolute positioning error and said relative positioning error, as a total positioning error for said relative position.

2. A position data decimation apparatus for use in a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position recording means for recording data expressing a plurality of said positions, wherein said position data decimation apparatus comprises:

position accuracy indication means for generating, in conjunction with each of said calculated positions, corresponding indication information relating to a positioning accuracy of said calculated position, and

position accuracy judgment means for selecting data expressing specific ones of said positions, to be recorded by said position recording means, with said selection based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating said positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites and calculating respectively corresponding absolute heading directions of said mobile body, and relative position sensing means for periodically calculating said positions of the mobile body as relative positions at times between successive calculations of said absolute positions and for calculating respectively corresponding relative heading directions, and wherein said position accuracy indication means comprises heading direction accuracy means for calculating, for each of sa id relative positions;

a direction error of an absolute heading direction obtained for an absolute position which precedes said relative position,

a direction error of a relative heading direction obtained for said relative position, and

the sum of said direction errors of the absolute heading direction and relative heading direction, as a total direction error for said relative position, to constitute said indication information.

3. A position data decimation apparatus for use in a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position recording means for recording data expressing a plurality of said positions, wherein said position data decimation apparatus comprises:

position accuracy indication means for generating, in conjunction with each of said calculated positions, corresponding indication information relating to a positioning accuracy of said calculated position; and

position accuracy judgment means for selecting data expressing specific ones of said positions, to be recorded by said position recording means, with said selection based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites, and wherein said position accuracy indication means comprises satellite number calculation means for calculating, for each of respective positions obtained by said position calculation means, a total number of said navigation satellites from which signals were acquired and utilized in determining said each position, with said total number constituting said indication information.

4. A position data decimation apparatus for use in a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position recording means for recording data expressing a plurality of said positions, wherein said position data decimation apparatus comprises:

position accuracy indication means for generating, in conjunction with each of said calculated positions,

corresponding indication information relating to a positioning accuracy of said calculated position; and

position accuracy judgment means for selecting data expressing specific ones of said positions, to be recorded by said position recording means, with said selection based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites, and wherein said position accuracy indication means comprises position calculation status detection means for obtaining, for each of respective positions obtained by said position calculation means, satellite acquisition status information for indicating whether or not said position was calculated based on successful acquisition of signals from said navigation satellites, with said satellite acquisition status information constituting said indication information.

5. A position data decimation apparatus for use in a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position data transmitting means operable for performing radio transmission of data expressing said positions, wherein said position data decimation apparatus comprises:

position accuracy indication means for generating, in conjunction with each of said calculated positions, corresponding indication information relating to a positioning accuracy of said calculated position, position data and indication information recording means for recording successively obtained ones of said positions in conjunction with respectively corresponding indication information, and

position data transmission judgment means operable for reading out a plurality of said recorded positions together with said respectively corresponding indication information, with said plurality of positions extending from a most recently obtained one of said positions up to a position which was obtained a predetermined amount of time prior to the current time point, and for supplying selected ones of said plurality of positions to said position data transmitting means, with said selection based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating said positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites, and relative position sensing means for periodically calculating said positions of the mobile body as relative positions at times between successive calculations of said absolute positions, and wherein said position accuracy indication means comprises position accuracy calculation means for calculating, for each of said relative positions, as said indication information;

an absolute positioning error of an absolute position which precedes said relative position,

a relative positioning error of said relative position, and

the sum of said absolute positioning error and said relative positioning error, as a total positioning error for said relative position.

6. A position data decimation apparatus for use in a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position data transmitting means operable for performing radio transmission of data expressing said positions, wherein said. position data decimation apparatus comprises:

position accuracy indication means for generating, in conjunction with each of said calculated positions, corresponding indication information relating to a positioning accuracy of said calculated position,

position data and indication information recording means for recording successively obtained ones of said positions in conjunction with respectively corresponding indication information, and

position data transmission judgment means operable for reading out a plurality of said recorded positions together with said respectively corresponding indication information, with said plurality of positions extending from a most recently obtained one of said positions up to a position which was obtained a predetermined amount of time prior to the current time point, and for supplying selected ones of said plurality of positions to said position data transmitting means, with said selection based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating said positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites and calculating respectively corresponding absolute heading directions of said mobile body, and relative position sensing means for periodically calculating said positions of the mobile body as relative positions at times between successive calculations of said absolute positions and for calculating respectively corresponding relative heading directions, and wherein said position accuracy indication means comprises heading direction accuracy means for calculating, for each of said relative positions, as said indication information;

a direction error of an absolute heading direction obtained for an absolute position which precedes said relative position,

a direction error of a relative heading direction obtained for said relative position, and

the sum of said direction errors of the absolute heading direction and relative heading direction, as a total direction error for said relative position, to constitute said indication information.

7. A position data decimation apparatus for use in a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position data transmitting means operable for performing radio transmission of data expressing said positions, wherein said position data decimation apparatus comprises:

position accuracy indication means for generating, in conjunction with each of said calculated positions, corresponding indication information relating to a positioning accuracy of said calculated position,

position data and indication information recording means for recording successively obtained ones of said positions in conjunction with respectively corresponding indication information, and

position data transmission judgment means operable for reading out a plurality of said recorded positions together with said respectively corresponding indication information, with said plurality of positions extending from a most recently obtained one of said positions up to a position which was obtained a predetermined amount of time prior to the current time point, and for supplying selected ones of said plurality of positions to said position data transmitting means, with said selection based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites, and wherein said position accuracy indication means comprises satellite number calculation means for calculating, for each of respective positions obtained by said position calculation means, a total number of said navigation satellites from which signals were acquired and utilized in determining said each position.

8. A position data decimation apparatus for use in a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position data transmitting means operable for performing radio transmission of data expressing said positions, wherein said position data decimation apparatus comprises:

position accuracy indication means for generating, in conjunction with each of said calculated positions, corresponding indication information relating to a positioning accuracy of said calculated position,

position data and indication information recording means for recording successively obtained ones of said positions in conjunction with respectively corresponding indication information, and

position data transmission judgment means operable for reading out a plurality of said recorded positions together with said respectively corresponding indication information, with said plurality of positions extending from a most recently obtained one of said positions up to a position which was obtained a predetermined amount of time prior to the current time point, and for supplying selected ones of said plurality of positions to said position data transmitting means, with said selection based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites, and wherein said position accuracy indication means comprises position calculation status detection means for obtaining, for each of respective positions obtained by said position calculation means, satellite acquisition status information for indicating whether or not said position was calculated based on successful acquisition of signals from said navigation satellites, with said satellite acquisition status information constituting said indication information.

9. A position data decimation apparatus for use in a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position data transmitting means operable for performing radio transmission of data expressing said positions, wherein said position data decimation apparatus comprises:

travel distance calculation means for calculating, in relation to each of said calculated positions of the mobile body, a corresponding travel distance which has been traveled by said mobile body from an immediately preceding one of said positions,

position data and travel distance recording means for recording successively obtained ones of said positions in conjunction with said corresponding travel distances, and

position data transmission judgement means operable for reading out a plurality of said recorded positions together with said corresponding travel distances, and for selecting the data of respective ones of said plurality of positions to be supplied to said position data transmitting means, with said selection being performed in accordance with respective amounts of cumulative distance of said positions from a most recently recorded one of said positions.

10. A position data decimation apparatus according to claim 9, wherein said position data transmission judgement section comprises means for selecting respective positions from at least a first and second set of positions from said plurality of positions, wherein said first set contains positions which extend from said most recently recorded position up to a position which is separated from said most recently recorded position by a first predetermined cumulative distance, and said second set contains positions which extend from said most recently recorded position up to a position which is separated from said most recently recorded position by a second predetermined cumulative distance, and wherein all of said first set of positions are supplied to said position data transmitting means to be transmitted thereby and periodically extracted ones of said second set of positions are supplied to said position data transmitting means to be transmitted thereby.

11. A method of position data decimation for application to a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position recording means for recording data expressing a plurality of said positions, the method comprising:

deriving in conjunction with each of said calculated positions, corresponding indication information relating to a positioning accuracy of said calculated position; and

selecting data expressing respective ones of said calculated positions, to be recorded by said position recording means, with said selection being based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating said positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites, and relative position sensing means for periodically calculating said positions of the mobile body as relative positions at times between successive calculations of said absolute positions, and wherein said deriving indication information comprises each of said relative positions;

calculating an absolute positioning error of an absolute position which precedes said relative position,

calculating a relative positioning error of said relative position, and

calculating the sum of said absolute positioning error and said relative positioning error, as a total positioning error for said relative position, with said total positioning error constituting said corresponding indication information.

12. A method of position data decimation for application to a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position recording means for recording data expressing a plurality of said positions, the method comprising:

deriving in conjunction with each of said calculated positions, corresponding indication information relating to a positioning accuracy of said calculated position; and

selecting data expressing respective ones of said calculated positions, to be recorded by said position recording means, with said selection being based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating said positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites and calculating respectively corresponding absolute heading directions of said mobile body, and relative position sensing means for periodically calculating said positions of the mobile body as relative positions at times between successive calculations of said absolute positions and for calculating respectively corresponding relative heading directions, and wherein said wherein said deriving corresponding indication information comprises, for each of said relative positions;

calculating a direction error of an absolute heading direction obtained for an absolute position which precedes said relative position,

calculating a direction error of a relative heading direction obtained for said relative position, and

calculating the sum of said direction errors of the absolute heading direction and relative heading direction, as a total direction error for said relative position, to constitute said corresponding indication information.

13. A method of position data decimation for application to a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position recording means for recording data expressing a plurality of said positions, the method comprising:

deriving in conjunction with each of said calculated positions, corresponding indication information relating to a positioning accuracy of said calculated position; and

selecting data expressing respective ones of said calculated positions, to be recorded by said position recording means, with said selection being based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites, and wherein said deriving corresponding indication information comprises, for each of respective positions obtained by said position calculation means, calculating a total number of said navigation satellites from which signals were acquired and utilized in determining said each position, with said number of navigation satellites constituting said corresponding indication information.

14. A method of position data decimation for application to a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position recording means for recording data expressing a plurality of said positions, the method comprising:

deriving in conjunction with each of said calculated positions, corresponding indication information relating to a positioning accuracy of said calculated position; and

selecting data expressing respective ones of said calculated positions, to be recorded by said position recording means, with said selection being based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites, and wherein said deriving corresponding indication information comprises deriving, for each of respective positions obtained by said position calculation means, satellite acquisition status information for indicating whether or not said position was calculated based on successful acquisition of signals from said navigation satellites, with said satellite acquisition status information constituting said corresponding indication information.

15. A method of position data decimation for application to a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position data transmitting means operable for performing radio transmission of data expressing said positions, the method comprising:

deriving, in conjunction with each of said calculated positions, corresponding indication information relating to a positioning accuracy of said calculated position,

recording successively obtained ones of said positions in conjunction with said corresponding indication information,

reading out a plurality of said recorded positions together with said corresponding indication information, with said plurality of positions extending from a most recently obtained one of said positions up to a position which was obtained a predetermined amount of time prior to the current time point, and

selecting data expressing respective ones of said plurality of positions, to be supplied to said position data transmitting means, with said selection being based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating said positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites, and relative position sensing means for periodically calculating said positions of the mobile body as relative positions at times between successive calculations of said absolute positions, and wherein said deriving corresponding indication information comprises, for each of said relative positions;

calculating an absolute positioning error of an absolute position which precedes said relative position,

calculating a relative positioning error of said relative position, and

calculating the sum of said absolute positioning error and said relative positioning error, as a total positioning error for said relative position, with said total positioning error constituting said corresponding indication information.

16. A method of position data decimation for application to a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position data transmitting means operable for performing radio transmission of data expressing said positions, the method comprising:

deriving, in conjunction with each of said calculated positions, corresponding indication information relating to a positioning accuracy of said calculated position,

recording successively obtained ones of said positions in conjunction with said corresponding indication information,

reading out a plurality of said recorded positions together with said corresponding indication information, with said plurality of positions extending from a most recently obtained one of said positions up to a position which was obtained a predetermined amount of time prior to the current time point, and

selecting data expressing respective ones of said plurality of positions, to be supplied to said position data transmitting means, with said selection being based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating said positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites and calculating respectively corresponding absolute heading directions of said mobile body, and relative position sensing means for periodically calculating said positions of the mobile body as relative positions at times between successive calculations of said absolute positions and for calculating respectively corresponding relative heading directions, and wherein said deriving corresponding indication information comprises, for each of said relative positions;

calculating a direction error of an absolute heading direction obtained for an absolute position which precedes said relative position,

calculating a direction error of a relative heading direction obtained for said relative position, and

calculating the sum of said direction errors of the absolute heading direction and relative heading direction, as a total direction error for said relative position, to constitute said indication information.

17. The method of position data decimation according to claim 16, wherein said position calculation means comprises absolute position sensing means for periodically calculating positions of the mobile body as respective absolute positions based on information from signals transmitted from navigation satellites, and wherein said step of deriving corresponding indication information comprises, for each of respective positions obtained by said position calculation means, calculating a total number of said navigation satellites from which signals were acquired and utilized in determining said each position.

18. A method of position data decimation for application to a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position data transmitting means operable for performing radio transmission of data expressing said positions, the method comprising:

deriving, in conjunction with each of said calculated positions, corresponding indication information relating to a positioning accuracy of said calculated position,

recording successively obtained ones of said positions in conjunction with said corresponding indication information,

reading out a plurality of said recorded positions together with said corresponding indication information, with said plurality of positions extending from a most recently obtained one of said positions up to a position which was obtained a predetermined amount of time prior to the current time point, and

selecting data expressing respective ones of said plurality of positions, to be supplied to said position data transmitting means, with said selection being based upon judgment of said corresponding indication information, wherein

said position calculation means comprises absolute position sensing means for periodically calculating positions of the mobile body as respective absolute positions based in information from signals transmitted from navigation satellites, and wherein said deriving corresponding indication information comprises, for each of respective positions obtained by said position calculation means, satellite acquisition status information for indicating whether or not said position was calculated based on successful acquisition of signals from said navigation satellites, with said satellite acquisition status information constituting said indication information.

19. A method of position data decimation apparatus for application to a mobile body navigation apparatus having position calculation means for calculating successive positions of a mobile body which transports said apparatus and position data transmitting means operable for performing radio transmission of data expressing said positions, the method comprising steps of:

calculating, in relation to each of said calculated positions of the mobile body, a corresponding travel distance which has been traveled by said mobile body from an immediately preceding one of said positions,

recording successively obtained ones of said positions in conjunction with said corresponding travel distances,

at a time subsequent to recording a plurality of said positions and corresponding travel distances, reading out said plurality of recorded positions together with said corresponding travel distances,

for each position thus read out, calculating a cumulative distance of said position from a most recently recorded one of said positions, based on said travel distances,

selecting specific ones of said plurality of positions, with said selected positions being determined in accordance with respective amounts of cumulative distance from said most recently recorded position, and

supplying said selected positions to said position data transmitting means, to be transmitted by radio.