Position sensing device and method

• US 8,510,044 B2
• Filed: 07/01/2008
• Issued: 08/13/2013
• Est. Priority Date: 07/12/2007
• Status: Active Grant

• Current Assignee: Alpine Electronics Incorporated (Alps Alpine Co., Ltd.)
• Original Assignee: Alpine Electronics Incorporated (Alps Alpine Co., Ltd.)
• Inventors: Watanabe, Takayuki, Hoshizaki, Takayuki
• Primary Examiner(s): Lubin, Valerie
• Assistant Examiner(s): COUPE, ANITA YVONNE
• Application Number:
  US12/166,062
• Publication Number:
  US 20090018772A1
• Time in Patent Office: 1,869 Days
• Field of Search: 701/221, 701/214, 701/472
• US Class Current: 701/472
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments
• CPC Class Codes: G01C 25/005 initial alignment, calibration or starting-up of inertial devices
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial

Abstract

A position sensing device and method are provided for executing correction processing based on a reliability and error index of each component of GPS output data to increase positioning accuracy. Correction processing is performed to correct a position determination result obtained through dead reckoning, and a vehicle speed, a pitch angle, and a sensor mounting angle used in position determination executed through dead reckoning in a measurement period of GPS in accordance with direction-specific positional components and speed components of a vehicle, which are measured with GPS to determine a reliability of each of the direction-specific positional components and speed components of the vehicle and calculate an error index of a component determined to be a reliable component, to set the degree of contribution of a measurement component determined to be unreliable to correction processing to zero or almost zero, and to reduce the degree of contribution of a measurement component determined to be reliable to correction processing in accordance with a value of the error index.

Claims

1. A position sensing device for detecting a current position of a vehicle, comprising:

a dead reckoning unit for determining a position of the vehicle by calculation based on dead reckoning at a predetermined cycle;

a GPS receiver;

a correction unit for executing correction processing for correcting a position determination result obtained through dead reckoning and for correcting a vehicle speed, a pitch angle, and a sensor mounting angle used in position determination executed through dead reckoning, wherein the correction processing is executed in accordance with multi-dimensional direction-specific positional components and speed components of the vehicle which are measured with the GPS receiver in a measurement period of the GPS receiver which is longer than the predetermined cycle; and

a GPS data determination unit for determining a reliability of each of the multi-dimensional direction-specific positional components and speed components of the vehicle, which are measured with the GPS receiver, and calculating an error index of each component determined to be a reliable component,

wherein the correction unit includes a unit for setting a degree of contribution of each measurement component determined to be an unreliable component to the correction processing to zero or almost zero, and reducing the degree of contribution of each measurement component determined to be a reliable component to the correction processing in accordance with a value of the error index.

2. The position sensing device according to claim 1, further comprising a second correction unit for measuring a vehicle speed using an output signal of a moving distance detecting sensor in a period longer than the predetermined cycle for dead reckoning and not longer than the GPS measurement period, and correcting the vehicle speed, the pitch angle, and the sensor mounting angle used in dead reckoning in accordance with a difference between the measured vehicle speed and the vehicle speed determined through dead reckoning.

3. The position sensing device according to claim 1, wherein the GPS data determination unit includes:

a reliability determination unit for determining a reliability of each of direction-specific positional components and speed components measured with the GPS receiver; and

an error index calculating unit for calculating an error index of a component determined to be a reliable component.

4. The position sensing device according to claim 3, wherein the error index calculating unit sets an error index of the component determined to be an unreliable component to a large value so as to minimize contribution of the component to the correction processing.

5. The position sensing device according to claim 3, wherein the correction unit executes the correction processing through a Kalman filter process, calculating a covariance matrix of a measurement error used for the Kalman filter process based on the error index, and reducing the degree of contribution of each measurement component to the correction processing in accordance with the error index based on the covariance matrix.

6. A position sensing device for detecting a current position of a vehicle, comprising:

a dead reckoning unit for determining the vehicle'"'"'s latitude, longitude, and position in a height direction at a first cycle based on a pitch angle θ and

a yaw angle Y relative to a horizontal plane of a dead reckoning sensor that outputs a signal according to acceleration of the vehicle and an amount of change in orientation of the vehicle, a mounting angle of the dead reckoning sensor, and a vehicle moving distance detected with a vehicle moving distance detection unit, and calculating a vehicle speed, Vsp, by use of an acceleration signal output from the dead reckoning sensor;

a GPS receiver;

a first correction unit for calculating a vehicle speed, Vx, at a second cycle not shorter than the first cycle using an output signal of the moving distance detecting unit, and correcting the vehicle speed, Vsp, the pitch angle θ

, and the mounting angle of the sensor, which are calculated with the dead reckoning unit, based on a difference between the calculated vehicle speed, Vx, and the vehicle speed calculated with the dead reckoning unit, Vsp,; and

a second correction unit for correcting the vehicle'"'"'s latitude, longitude, and position in a height direction, and a vehicle speed calculated with the dead reckoning unit at a third cycle not shorter than the second cycle, and the pitch angle 0, the yaw angle Y, and the mounting angle of the sensor based on a vehicle'"'"'s latitude, longitude, and position in the height direction, and a vehicle speed output from the GPS receiver, and a vehicle'"'"'s latitude, longitude, and position in the height direction, and a vehicle speed output from the dead reckoning unit, and a sensor offset value thereof; and

a GPS data determination unit for determining a reliability of each of multi-dimensional direction-specific positional components and speed components of the vehicle, which are measured with the GPS receiver, and calculating an error index of each component determined to be a reliable component,

wherein the second correction unit includes a unit for setting a degree of contribution of each measurement component determined to be an unreliable component to the correction processing to zero or almost zero, and reducing the degree of contribution of each measurement component determined to be a reliable component to the correction processing in accordance with a value of the error index.

7. The position sensing device according to claim 6, wherein the GPS data determination unit includes:

a reliability determination unit for determining a reliability of each of direction-specific positional components and speed components measured with the GPS receiver; and

an error index calculating unit for calculating an error index of a component determined to be a reliable component.

8. The position sensing device according to claim 7, wherein the error index calculating unit sets an error index of the component determined to be an unreliable component to a large value so as to minimize contribution of the component to the correction processing.

9. A position sensing device for detecting a current position of a vehicle, comprising:

a dead reckoning unit for determining a position of the vehicle by calculation based on dead reckoning at a predetermined cycle;

a GPS receiver;

a correction unit for executing correction processing for correcting a position determination result obtained through dead reckoning and for correcting a vehicle speed, a pitch angle, and a sensor mounting angle used in position determination executed through dead reckoning, wherein the correction processing is executed in accordance with multi-dimensional direction-specific positional components and speed components of the vehicle which are measured with the GPS receiver in a measurement period of the GPS receiver which is longer than the predetermined cycle; and

a GPS data determination unit for determining a reliability of each of the multi-dimensional direction-specific positional components and speed components of the vehicle, which are measured with the GPS receiver, and calculating an error index of a component determined to be a reliable component,

wherein the correction unit includes;

a unit for executing control not to perform the correction processing if at least one of the measurement components is determined to be an unreliable component; and

a unit for executing the correction processing and reducing a degree of contribution of each measurement component to the correction processing in accordance with a value of the error index if all measurement components are determined to be a reliable component.

10. A position sensing device for detecting a current position of a vehicle, comprising:

a dead reckoning unit for determining a position of the vehicle by calculation based on dead reckoning at a predetermined cycle;

a GPS receiver;

a correction unit for executing correction processing for correcting a position determination result obtained through dead reckoning and for correcting a vehicle speed, a pitch angle, and a sensor mounting angle used in position determination executed through dead reckoning, wherein the correction processing is executed in accordance with multi-dimensional direction-specific positional components and speed components of the vehicle which are measured with the GPS receiver in a measurement period of the GPS receiver which is longer than the predetermined cycle; and

a GPS data determination unit for determining a reliability of each of the multi-dimensional direction-specific positional components and speed components of the vehicle, which are measured with the GPS receiver, and calculating an error index of a component determined to be a reliable component,

wherein the correction unit includes;

a unit for executing, if GPS measurement components are divided into a speed component group and a positional component group, and at least one of the measurement components in a group is determined to be an unreliable component, control not to perform the correction processing by use of the measurement components in the group including the unreliable component; and

a unit for executing, if all measurement components in a group are determined to be a reliable component, the correction processing by use of the measurement components in the group and reducing a degree of contribution of each measurement component to the correction processing in accordance with a value of the error index.