POSITION OUTPUT DEVICE USING SATELLITE NAVIGATION SYSTEM

• US 20140365117A1
• Filed: 12/06/2012
• Published: 12/11/2014
• Est. Priority Date: 12/09/2011
• Status: Active Grant

• Current Assignee: Tokyo Keiki Incorporated
• Original Assignee: Tokyo Keiki Incorporated
• Inventors: Okamura, Nobuyuki, Arakane, Hiroomi, Sagawa, Takao
• Granted Patent: US 9,121,929 B2
• Time in Patent Office: Days
• US Class Current: 701/469
• CPC Class Codes: G01C 21/188 for accumulated errors, e.g. by coupling inertial systems with absolute positioning systems
• CPC Class Codes: G01S 19/00 Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
• CPC Class Codes: G01S 19/426 by combining or switching between position solutions or signals derived from different modes of operation in a single system

Abstract

A position output device for outputting position data indicating a current position of an object, is based on position data of a determined current position of the object as determined by a satellite navigation system. When a position jump has occurred in the position data from the satellite navigation system, an appropriate current position is outputted. An estimated current position is generated based on the output position outputted at the latest update time. It is determined whether or not a position jump has occurred, based on the distance between the estimated position and the satellite navigation system-based determined position, which is being updated by the satellite navigation system. When it is determined that a position jump has occurred, a position adjustment vector is generated by calculation, which is then used to generate an adjusted position.

Claims

1. A position output device for outputting position data indicating a current position of an object, based on position data of a determined current position of the object as determined by a satellite navigation system, comprising:

a satellite navigation system-based data fetcher for fetching, into the position output device, a satellite navigation system-based determined current position which is being updated by the satellite navigation system;

an output position calculator for successively generating, by calculation, an output position to be outputted at each successive update time;

an estimated current position calculator for generating, by calculation, an estimated current position of the object, based on the latest output position outputted at the latest update time;

a position jump occurrence determinator for determining whether or not a position jump has occurred, based on the distance between the estimated current position and the satellite navigation system-based determined current position;

a position adjustment vector calculator for generating, by calculation, a position adjustment vector for use in effecting adjustment to the satellite navigation system-based determined current position, the position adjustment vector calculator being adapted to be activated when it is determined that a position jump has occurred;

a position return determinator for determining whether or not the distance between the estimated current position and the satellite navigation-system based determined current position is greater than a predetermined threshold distance, the position return determinator being adapted to be activated when it is determined that no position jump has occurred after occurrence of a position jump;

a second position adjustment vector calculator for generating, by calculation, a second position adjustment vector for use in effecting adjustment to the satellite navigation system-based determined current position, the second position adjustment vector calculator being adapted to be activated when it is determined that the distance between the estimated current position and the satellite navigation-system based determined current position is greater than the predetermined threshold distance;

the position adjustment vector calculator being adapted to generate the position adjustment vector having a magnitude of such a length;

if the distance between the estimated current position and the satellite navigation system-based determined current position is reduced by this length at each successive update time, then that distance is reduced to zero after a predetermined time period which is longer than the update interval;

the second position adjustment vector calculator being adapted to generate the second position adjustment vector having a magnitude of such a length;

if the distance between the estimated current position and the satellite navigation system-based determined current position is repetitively reduced by this length at each successive update time, then that distance is reduced to zero after a predetermined time period which is longer than the update interval and shorter than the above mentioned predetermined time period for the position adjustment vector calculator; and

the output position calculator being adapted i) to generate such an output position that corresponds to the estimated current position adjusted with the position adjustment vector when it is determined that a position jump has occurred and ii) to generate such an output position that corresponds to the estimated current position adjusted with the second position adjustment vector when it is determined that no position jump has occurred after occurrence of a position jump and that the distance between the estimated current position and the satellite navigation-system based determined current position is greater than a predetermined threshold distance.

2. A position output device using a satellite navigation system according to claim 1, wherein:

the position adjustment vector has a magnitude which corresponds to the distance between the estimated current position and the satellite navigation system-based determined current position, multiplied by the quotient of the length of the update interval divided by the length of a first time period.

3. A position output device using a satellite navigation system according to claim 2, wherein:

the second position adjustment vector has a magnitude which corresponds to the distance between the estimated current position and the satellite navigation system-based determined current position, multiplied by the quotient of the length of the update interval divided by the length of a second time period, wherein the second time period is shorter than the first time period.

4. A position output device using a satellite navigation system according to claim 1, further comprising:

an inertial navigation system-based data fetcher for fetching, into the position output device, an inertial navigation system-based determined velocity which is being updated by the inertial navigation system;

the estimated current position calculator being adapted to generate, by calculation, the estimated current position based on the inertial navigation system-based determined velocity.

5. A position output device using a satellite navigation system according to claim 1 to 4, wherein:

the output position calculator is adapted to use the estimated current position as a new output position when it is determined that no position jump has occurred while the satellite navigation system-based determined position has not been updated.

6. A position output device using a satellite navigation system according to claim 1, wherein:

the output position calculator is adapted to use the estimated current position as a new output position when it is determined that no position jump has occurred while the satellite navigation system-based determined position has been updated.