Radar device

• US 20060007036A1
• Filed: 06/30/2005
• Published: 01/12/2006
• Est. Priority Date: 07/06/2004
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Natsume, Kazuma, Miyake, Yasuyuki
• Granted Patent: US 7,474,252 B2
• Time in Patent Office: Days
• US Class Current: 342/70
• CPC Class Codes: G01S 13/34 using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9321 Velocity regulation, e.g. cruise control
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 3/74 Multi-channel systems specially adapted for direction-finding, i.e. having a single antenna system capable of giving simultaneous indications of the directions of different signals systems in which the directions of different signals are determined sequentially and displayed simultaneously G01S3/04, G01S3/14

Abstract

A radar device uses a transmission signal outputted from a transmission antenna and a reception signal as an incoming wave reflected from a target object through an arrangement of reception antennas for estimating an angle of the incoming wave. An incoming wave estimation process stores a threshold for each beat frequency of the beat signal, and distinguishes the incoming wave in a signal space from the incoming wave in a non-signal space using the threshold. The estimation process facilitates an accurate estimation of the incoming wave in MUSIC method, ESPRIT method or the like.

Claims

1. A radar device using a transmission signal outputted from a transmission antenna and a reception signal as an incoming wave reflected from a target object through an arrangement of reception antennas for estimating an angle of the incoming wave comprising:

a beat signal generation means for generating a beat signal from a difference of the transmission signal and the reception signal in a frequency element;

a self-correlation matrix calculation means for calculating a self-correlation matrix based on the beat signal;

an eigenvalue calculation means for calculating an eigenvalue using the self-correlation matrix; and

an incoming wave estimation means for estimating a number of the incoming wave,

wherein the incoming wave estimation means stores a threshold for each beat frequency of the beat signal, and

the incoming wave estimation means distinguishes the incoming wave in a signal space from the incoming wave in a non-signal space using the threshold for estimating the number of the incoming wave.

4. The radar device according to claim 1,

wherein the incoming wave estimation means stores a maximum number of the target object for each target detection area covered by the incoming wave, and

the incoming wave estimation means rounds the number of the incoming wave to the maximum number when an estimated number of the incoming wave exceeds the maximum number.

6. The radar device according to claim 1 further comprising,

a history data storage means for storing a history data including a distance and a relative speed of the target object at a detection cycle of the target object,

wherein the incoming wave estimation means predicts an arrangement of the target object in a next detection cycle, and

the incoming wave estimation means estimates the number of the incoming wave based on the predicted arrangement of the target object.

2. A radar device using a transmission signal outputted from a transmission antenna and a reception signal as an incoming wave reflected from a target object through an arrangement of reception antennas for estimating an angle of the incoming wave comprising:

a beat signal generation means for generating a beat signal from a difference of the transmission signal and the reception signal in a frequency element;

a self-correlation matrix calculation means for calculating a self-correlation matrix based on the beat signal;

an eigenvalue calculation means for calculating an eigenvalue using the self-correlation matrix; and

an incoming wave estimation means for estimating a number of the incoming wave,

wherein the incoming wave estimation means stores a threshold for each phase of the beat signal, and

the incoming wave estimation means distinguishes the incoming wave in a signal space from the incoming wave in a non-signal space using the threshold for estimating the number of the incoming wave.

3. A radar device using a transmission signal outputted from a transmission antenna and a reception signal as an incoming wave reflected from a target object through an arrangement of reception antennas for estimating an angle of the incoming wave comprising:

a beat signal generation means for generating a beat signal from a difference of the transmission signal and the reception signal in a frequency element;

a self-correlation matrix calculation means for calculating a self-correlation matrix based on the beat signal;

an eigenvalue calculation means for calculating an eigenvalue using the self-correlation matrix; and

an incoming wave estimation means for estimating a number of the incoming wave,

wherein the incoming wave estimation means stores a threshold for each delay time of the beat signal, and

the incoming wave estimation means distinguishes the incoming wave in a signal space from the incoming wave in a non-signal space using the threshold for estimating the number of the incoming wave.

5. A radar device using a transmission signal outputted from a transmission antenna and a reception signal as an incoming wave reflected from a target object through an arrangement of reception antennas for estimating an angle of the incoming wave comprising:

a beat signal generation means for generating a beat signal from a difference of the transmission signal and the reception signal in a frequency element;

a self-correlation matrix calculation means for calculating a self-correlation matrix based on the beat signal;

an eigenvalue calculation means for calculating an eigenvalue using the self-correlation matrix; and

an incoming wave estimation means for estimating a number of the incoming wave,

wherein the incoming wave estimation means stores a maximum number of the target object for each target detection area covered by the incoming wave, and

the incoming wave estimation means rounds the number of the incoming wave to the maximum number when an estimated number of the incoming wave exceeds the maximum number.

7. A radar device using a transmission signal outputted from a transmission antenna and a reception signal as an incoming wave reflected from a target object through an arrangement of reception antennas for estimating an angle of the incoming wave comprising:

a beat signal generation means for generating a beat signal from a difference of the transmission signal and the reception signal in a frequency element;

a self-correlation matrix calculation means for calculating a self-correlation matrix based on the beat signal;

an eigenvalue calculation means for calculating an eigenvalue using the self-correlation matrix;

an incoming wave estimation means for estimating a number of the incoming wave; and

a history data storage means for storing a history data including a distance and a relative speed of the target object at a detection cycle of the target object, wherein the incoming wave estimation means predicts an arrangement of the target object in a next detection cycle, and

the incoming wave estimation means estimates the number of the incoming wave based on the predicted arrangement of the target object.

8. The radar device according to claim 7,

wherein the incoming wave estimation means calculate the number of difference of the target object in the previous detection cycle and the number of the target object in the current detection cycle,

the incoming wave estimation means calculates the number of difference of the incoming wave estimated in the previous detection cycle and the number of the incoming wave estimated in the current detection cycle,

the incoming wave estimation means compares the number of difference between the number of difference of the target object and the number of difference of the incoming wave, and

the incoming wave estimation means estimates the number of the incoming wave by adding the number of difference of the target object when the number of difference of the target object is not equal to the number of difference of the incoming wave.

9. A radar device using a transmission signal outputted from a transmission antenna and a reception signal as an incoming wave reflected from a target object through an arrangement of reception antennas for estimating an angle of the incoming wave comprising:

a beat signal generation means for generating a beat signal from a difference of the transmission signal and the reception signal in a frequency element;

a self-correlation matrix calculation means for calculating a self-correlation matrix based on the beat signal;

an eigenvalue calculation means for calculating an eigenvalue using the self-correlation matrix;

an incoming wave estimation means for estimating a number of the incoming wave; and

a history data storage means for storing a history data including a distance and a relative speed of the target object at a detection cycle of the target object,

wherein the incoming wave estimation means stores a threshold for the eigenvalue,

the incoming wave estimation means distinguishes the eigenvalue in a signal space from the eigenvalue in a non-signal space using the threshold for estimating the number of the incoming wave,

the incoming wave estimation means predicts an arrangement of the target object in a next detection cycle, and

the incoming wave estimation means changes a value of the threshold based on the predicted arrangement of the target object.

10. A radar device using a transmission signal outputted from a transmission antenna and a reception signal as an incoming wave reflected from a target object through an arrangement of reception antennas for estimating an angle of the incoming wave comprising:

a beat signal generation means for generating a beat signal from a difference of the transmission signal and the reception signal in a frequency element;

a self-correlation matrix calculation means for calculating a self-correlation matrix based on the beat signal;

an eigenvalue calculation means for calculating an eigenvalue using the self-correlation matrix; and

an incoming wave estimation means for estimating a number of the incoming wave,

wherein the incoming wave estimation means stores a predetermined number of the incoming wave,

the incoming wave estimation means distinguishes the eigenvalue in a signal space from the eigenvalue in a non-signal space by using the predetermined number of the incoming wave for a temporary estimation,

the incoming wave estimation means calculates an angle of each incoming wave based on the temporary estimation,

the incoming wave estimation means calculates a signal intensity of the incoming wave at the angle of each incoming wave,

the incoming wave estimation means stores a threshold for the signal intensity, and

the incoming wave estimation means estimates the number of the incoming wave by determining whether the signal intensity exceeds the the threshold.

11. The radar device according to claim 10,

wherein the signal intensity is calculated by using a MUSIC spectrum in a MUSIC method.

12. The radar device according to claim 10,

wherein the signal intensity is calculated by using a diagonal section of a matrix S in Formula 1 when S represents a signal correlation matrix, A represents a direction matrix, Rxx represents a self-correlation matrix of the reception signal xi(t) of the incoming wave, σ

² represents a heat noise coefficient and I represents a unit matix.

S=(A^HA)<sup>−

1</sup>A^H(R_XX−

σ

²I)A(A^HA)<sup>−

1</sup>  

 

[Formula 1]

13. The radar device according to claim 10,

wherein the incoming wave estimation means stores the thresholds for each beat frequency, and

the incoming wave estimation means stores the threshold for the signal intensity based on the thresholds for each beat frequency.

14. The radar device according to claim 10,

wherein the incoming wave estimation means stores the thresholds for each phase of the beat signal, and

the incoming wave estimation means stores the threshold for the signal intensity based on the thresholds for each phase of the beat signal.

15. The radar device according to claim 10,

wherein the incoming wave estimation means stores the thresholds for each delay time of the beat signal, and

the incoming wave estimation means stores the threshold for the signal intensity based on the thresholds for each beat frequency.

16. The radar device according to claim 10 further comprising:

a history data storage means for storing a history data including a distance and a relative speed of the target object based on the beat signal.