ESTIMATION APPARATUS

• US 20160018219A1
• Filed: 03/04/2014
• Published: 01/21/2016
• Est. Priority Date: 03/04/2013
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Suzuki, Koichiro, Sakamoto, Mai
• Granted Patent: US 10,077,979 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01B 21/16 for measuring distance of clearance between spaced objects
• CPC Class Codes: G01S 11/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: G01S 13/347 using more than one modulation frequency
• CPC Class Codes: G01S 13/38 wherein more than one modulation frequency is used
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/584 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/726 Multiple target tracking
• CPC Class Codes: G01S 13/931 of land vehicles

Abstract

An estimation apparatus includes a distance estimator. The distance estimator performs regression analysis using, as samples, an observation of distance and an observation at each time within a predetermined period obtained by an observer. The estimation apparatus estimates that a value of the distance upon a value of a displacement calculated in accordance with a regression equation based on the regression analysis being zero shows a value of the distance to the forward object at a start time.

Claims

1. An estimation apparatus comprising:

displacement calculation means that uses an observation of a velocity of a forward object observed by an observer at each of times within a predetermined period to calculate, for each of the times, a temporal integral value of the velocity observations from a start time of the predetermined period to a corresponding one of the times, the observer observing a distance to the forward object, the temporal integral value calculated for each of the times serving as an observation of a displacement of the forward target within the start time to a corresponding one of the times; and

distance estimation means for;

performing regression analysis using, as samples, observations of the distance and the displacement observations at the respective times within the predetermined period, the regression analysis being based on the distance as an objective variable and the displacement as an explanatory variable; and

estimating that a value of the distance upon a value of the displacement calculated in accordance with a regression equation based on the regression analysis being zero shows a value of the distance to the forward object at the start time.

2. The estimation apparatus according to claim 1 further comprising:

correction means for performing state estimation of the forward object using a state estimation filter based on a linear state space model to correct the distance observations and the velocity observations at the respective times, wherein;

the displacement calculation means calculates, as the displacement observation at each of the times, a temporal integral value of the corrected velocity observations by the correction means; and

the distance estimation means performs the regression analysis using, as the samples, the corrected distance observations at the respective times by the correction means and the displacement observations at the respective times.

3. The estimation apparatus according to claim 2, wherein:

the state estimation filter based on the linear state space model is a linear Kalman filter.

4. The estimation apparatus according to claim 1, wherein:

the distance estimation means estimates, as a value of the distance at each of the times, a sum of the estimated value of the distance at the start time and the displacement observation at a corresponding one of the times.

5. The estimation apparatus according to claim 2, wherein:

the distance estimation means estimates, as a value of the distance at each of the times, a sum of the estimated value of the distance at the start time and the displacement observation at a corresponding one of the times.

6. The estimation apparatus according to claim 3, wherein:

the distance estimation means estimates, as a value of the distance at each of the times, a sum of the estimated value of the distance at the start time and the displacement observation at a corresponding one of the times.

7. The estimation apparatus according to claim 4, wherein:

the observer comprises an apparatus for further observing an orientation of the forward object,

the estimation apparatus further comprising;

a position estimation means for estimating, according to the value of the distance at each of the times estimated by the distance estimation means and observations of the orientation by the observer, a position of the forward object in an orthogonal coordinate system at each of the times.

8. The estimation apparatus according to claim 7, wherein:

the position estimation means comprises;

conversion means for converting a position of the forward object at each of the times into a position of the forward object in an X-Y coordinate system as the orthogonal coordinate system at a corresponding one of the times, the position of the forward object at each of the times being specified based on the value of the distance at a corresponding one of the times estimated by the distance estimation means and a corresponding value of the orientation observations,

the position estimation means being configured to;

perform regression analysis using, as samples, an X coordinate of the position at each of the times obtained by the conversion to calculate a function representing a correlation between the time and the X coordinates; and

perform regression analysis using, as samples, a Y coordinate of the position at each of the times to calculate a function {Y(t)} representing a correlation between the time and the Y coordinates, thus estimating the position of the forward object at each of the times.

9. The estimation apparatus according to claim 7, further comprising:

state estimation means for estimating the position and the velocity of the forward object using a state estimation filter based on a non-linear state space model; and

initial value setting means for setting, as initial values associated with the respective position and velocity of the forward object for the state estimation filter used by the state estimation means, a position and velocity of the forward object at a time corresponding to the initial values,

the position and velocity at the time corresponding to the initial values being specified from the position estimated by the position estimation means.

10. The estimation apparatus according to claim 8, further comprising:

state estimation means for estimating the position and the velocity of the forward object using a state estimation filter based on a non-linear state space model; and

initial value setting means for setting, as initial values associated with the respective position and velocity of the forward object for the state estimation filter used by the state estimation means, a position and velocity of the forward object at a time corresponding to the initial values,

the position and velocity at the time corresponding to the initial values being specified from the position estimated by the position estimation means.

11. The estimation apparatus according to claim 10, wherein:

the state estimation filter based on the non-linear state space model is a non-linear Kalman filter.

12. The estimation apparatus according to claim 11, wherein:

the non-linear Kalman filter is an extended Kalman filter.

13. The estimation apparatus according to claim 1, wherein:

the observer is configured to;

transmit radar waves;

receive echoes;

observe the velocity of the forward object according to frequency information included in received signals based on the echoes; and

observe the distance to the forward object according to phase information included in the received signals.

14. The estimation apparatus according to claim 1, wherein:

the observer is designed as a dual frequency continuous wave apparatus to;

transmit radar waves;

receive echoes;

observe the velocity of the forward object according to received signals based on the echoes;

observe the distance to the forward object according to the received signals.