Positioning device

• US 9,864,064 B2
• Filed: 06/27/2012
• Issued: 01/09/2018
• Est. Priority Date: 06/27/2012
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Ishigami, Tadatomi, Maeda, Atsushi, Fujii, Masatoshi, Chiyonobu, Hirokazu, Fujimoto, Kohei
• Primary Examiner(s): Edwards, Jerrah
• Application Number:
  US14/406,236
• Publication Number:
  US 20150149073A1
• Time in Patent Office: 2,022 Days
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments
• CPC Class Codes: G01C 21/30 Map- or contour-matching
• CPC Class Codes: G01S 19/13 Receivers
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 19/42 Determining position

Abstract

An object of the present invention is to provide a positioning device which can more reliably and frequently correct a own vehicle position earlier, reliably detect an error matching state or a straying state earlier and correct the position to a correct position. The positioning device according to the present invention includes a GPS receiver, a GPS position calculating unit which calculates pseudo distances to the GPS satellites based on the transmission signals, and calculates a re-calculated GPS position which is the own vehicle position based on the pseudo distances, and a multipath influence evaluating unit which evaluates a multipath influence on the GPS position based on a difference between the GPS position calculated by the GPS receiver and the re-calculated GPS position calculated by the GPS position calculating unit.

Claims

1. A positioning device comprising:

a first moving body position calculating unit that receives transmission signals transmitted from a plurality of GPS satellites, obtains pseudo distances to said GPS satellites and a Doppler shift based on the transmission signals, and calculates a first moving body position that is a position of a moving body, based on said obtained pseudo distances and said obtained Doppler shift;

a second moving body position calculating unit that calculates a second moving body position that is the position of said moving body, based on said pseudo distances;

a multipath influence evaluating unit that evaluates an influence of a multipath on said first moving body position based on a difference between said first moving body position calculated by said first moving body position calculating unit and said second moving body position calculated by said second moving body position calculating unit;

a calculating unit that calculates a time difference between said pseudo distances as a delta range, and calculates a first range rate based on said Doppler shift of said transmission signals;

a built-in clock error estimating unit that estimates an error of a built-in clock of said moving body as a built-in clock error based on a difference between said delta range and said first range rate;

a range rate estimating unit that estimates a second range rate in case that said moving body stops, based on positions and velocities of said GPS satellites based on said transmission signals and said second moving body position, and corrects said first range rate calculated by said calculating unit, based on said built-in clock error; and

a moving body velocity/azimuth calculating unit that calculates a velocity of said moving body and a second moving body azimuth that is an azimuth of said moving body, based on positions of said GPS satellites based on said transmission signals and said second moving body position, said second rage rate estimated by said range rate estimating unit and said first range rate corrected by said range rate estimating unit,

wherein said multipath influence evaluating unit evaluates the influence of the multipath on said first moving body position based on a difference between a first moving body azimuth that is a moving direction of said first moving body position and said second moving body azimuth.

2. The positioning device according to claim 1, wherein said multipath influence evaluating unit calculates pseudo distance smoothing values obtained by adding said first range rate to said pseudo distances in case that said evaluated influence of the multipath is a predetermined level or less, and evaluates the influence of the multipath per GPS satellite based on a pseudo distance error that is a difference between said pseudo distances and said pseudo distance smoothing values.

3. The positioning device according to claim 2, wherein said multipath influence evaluating unit re-selects said pseudo distances in case that said evaluated influence of the multipath is a predetermined level or less after a predetermined time passes.

4. The positioning device according to claim 1, wherein said multipath influence evaluating unit adds a difference between said delta range and said first range rate, and evaluates the influence of the multipath per GPS satellite based on errors of said pseudo distances calculated by subtracting from an addition result a predetermined rate of a moving average of said difference.

5. The positioning device according to claim 1, further comprising:

a velocity sensor that outputs a pulse signal corresponding to a moving distance of said moving body;

a distance measurement unit that measures at least a moving distance of said moving body based on said pulse signal outputted from said velocity sensor;

an angular velocity sensor that outputs a voltage corresponding to a yaw rate of said positioning device;

a yaw angle measurement unit that measures a yaw angle based on the voltage outputted from said angular velocity sensor;

a moving body position/azimuth calculating unit that calculates a third moving body position that is a position of said moving body and a third moving body azimuth that is an azimuth direction of said moving body, based on said moving distance measured by said distance measurement unit and said yaw angle measured by said yaw angle measurement unit; and

a moving body position/azimuth correcting unit that corrects said third moving body position and said third moving body azimuth based on said first moving body position and said second moving body azimuth in case that said multipath influence evaluating unit evaluates that the influence of the multipath is the predetermined level or less.

6. The positioning device according to claim 5, further comprising a moving body position/azimuth error calculating unit that calculates a difference between the third moving body position and said first moving body position as a first moving body position error based on said third moving body position corrected by said moving body position/azimuth correcting unit, and calculates a difference between the third moving body azimuth and said first moving body azimuth as a first moving body azimuth error based on said third moving body azimuth corrected by said moving body position/azimuth correcting unit.

7. The positioning device according to claim 5, wherein said moving body position/azimuth correcting unit determines that said third moving body position or said third moving body azimuth that is not corrected until driving is performed a predetermined distance or more or a predetermined angle or more is invalid, and determines that said third moving body position or said third moving body azimuth that is corrected until driving is performed the predetermined distance or more or the predetermined angle or more is valid.

8. The positioning device according to claim 7, further comprising a hybrid position/azimuth calculating unit that updates a fourth moving body position and a fourth moving body azimuth based on said moving distance measured by said distance measurement unit and said yaw angle measured by said yaw angle measurement unit, and corrects said fourth moving body position and said fourth moving body azimuth based on a first moving body position error and a first moving body azimuth error in case that said third moving body position and said third moving body azimuth are valid, said first moving body position and said first moving body azimuth, and said evaluation of said multipath influence evaluating unit.

9. The positioning device according to claim 8, further comprising a road matching unit that identifies the position of said moving body on a road link on a map based on said fourth moving body position and said fourth moving body azimuth calculated by said hybrid position/azimuth calculating unit.