Position Estimation Device and Position Estimation Method

• US 20110208496A1
• Filed: 02/17/2011
• Published: 08/25/2011
• Est. Priority Date: 02/24/2010
• Status: Active Grant

• Current Assignee: Clarion Co., Ltd. (Faurecia SA)
• Original Assignee: Clarion Co., Ltd. (Faurecia SA)
• Inventors: Yokota, Takayoshi, Okada, Kazuhiro, Liu, Zhixing, Kohida, Hiroyuki, Aoki, Toshiyuki, Bando, Mikio, Hiruta, Tomoaki
• Granted Patent: US 9,057,781 B2
• Time in Patent Office: Days
• US Class Current: 703/2
• CPC Class Codes: G01S 19/40 Correcting position, velocity or attitude
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled
• CPC Class Codes: G01S 5/017 Detecting state or type of motion
• CPC Class Codes: G01S 5/018 Involving non-radio wave signals or measurements

Abstract

A position estimation device includes: a mathematical expression model processing unit that calculates a position of a mobile object, a condition quantity indicating a moving condition of the mobile object and an error in the condition quantity through filtering processing executed by using a probability model based upon an attitude information and a positioning information of the mobile object having been obtained from sensors and a specific mathematical expression model among a plurality of mathematical expression models expressing behavior of the mobile object; a threshold calculation unit that calculates a threshold candidate value for a threshold value to be used as a criterion when selecting the specific mathematical expression model, by using the error; a threshold value determining unit that determines the threshold value based upon the threshold candidate value; and a mathematical expression model selection unit that selects the specific mathematical expression model based upon the threshold value.

Claims

1. A position estimation device, comprising:

a mathematical expression model processing unit that obtains attitude information and positioning information indicating an attitude and a measured position of a mobile object from sensors and calculates a position of the mobile object, a condition quantity indicating a moving condition of the mobile object and an error in the condition quantity through filtering processing executed by using a probability model based upon the attitude information and the positioning information having been obtained and a specific mathematical expression model among a plurality of mathematical expression models expressing behavior of the mobile object, which are acquired in advance;

a threshold calculation unit that calculates a threshold candidate value for a threshold value to be used as a criterion when selecting the specific mathematical expression model, by using the error having been calculated by the mathematical expression model processing unit;

a threshold value determining unit that determines the threshold value based upon the threshold candidate value; and

a mathematical expression model selection unit that selects the specific mathematical expression model based upon the threshold value determined by the threshold value determining unit.

2. A position estimation device according to claim 1, wherein:

restrictions imposed with regard to a valid range within which each of the plurality of mathematical expression models expressing the behavior is applicable to the behavior, are defined based upon information that can be collected through observation made from outside or based upon the position, the condition quantity and the error calculated by the mathematical expression model processing unit;

the threshold value determining unit determines the threshold value based upon values representing extents of the error calculated each in correspondence to one of the plurality of mathematical expression models; and

the mathematical expression model selection unit selects the specific mathematical expression model in correspondence to the restrictions.

3. A position estimation device according to claim 2, further comprising:

a database in which the restrictions and the threshold value are stored.

4. A position estimation method, comprising:

obtaining attitude information and positioning information indicating an attitude and a measured position of a mobile object from sensors;

calculating a position of the mobile object, a condition quantity indicating a moving condition of the mobile object and an error in the condition quantity through filtering processing executed by using a probability model based upon the attitude information and the positioning information having been obtained and a specific mathematical expression model among a plurality of mathematical expression models expressing behavior of the mobile object, which are acquired in advance;

calculating a threshold candidate value for a threshold value to be used as a criterion when selecting the specific mathematical expression model, by using the error having been calculated;

determining the threshold value based upon the candidate value; and

selecting the specific mathematical expression model based upon the threshold value having been determined.

5. A position estimation method according to claim 4, wherein:

restrictions imposed with regard to a valid range, within which each of the plurality of mathematical expression models expressing the behavior is applicable to the behavior, are defined based upon information that can be collected through observation made from outside or based upon the position, the condition quantity and the error having been calculated;

the threshold value is determined based upon values representing extents of the error calculated each in correspondence to one of the plurality of mathematical expression models; and

the specific mathematical expression model is selected in correspondence to the restrictions.