Radar device, vehicle, and moving object speed detection method

Patent metadata

Field	Value
Publication number	US-9958541-B2
Application number	US-201514839595-A
Country	US
Kind code	B2
Filing date	Aug 28, 2015
Priority date	Sep 12, 2013
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

A radar device mounted in a moving object includes a radar transmitter and a radar receiver. The radar receiver includes a plurality of antenna brunch processors that perform correlation processing of the received returning signals and the radar transmission signal, and generate respective correlation signals each including arrival delay information of each of the received returning signals, an electric power profile generator that generates an electric power profiles for each arrival direction of the received returning signals and Doppler frequency component, using the generated correlation signals, and a stationary object group distribution generator that, based on the generated electric power profiles, obtains a first distribution of a Doppler frequency components of a stationary object group including a plurality of stationary objects as the plurality of targets in the perimeter of the moving object, for each azimuth angle.

First claim

What is claimed is:

1. A radar device mounted in a moving object, the radar device comprising:
a radar transmitter that transmits a radio-frequency radar transmission signal from a transmission antenna, at each transmission cycle; and
a radar receiver that receives a plurality of returning signals that are generated as a result of the radar transmission signal reflected off of a plurality of targets, by a plurality of reception antennas,
wherein the radar receiver includes
a plurality of antenna brunch processors that perform correlation processing of the received returning signals and the radar transmission signal, and generate respective correlation signals each including arrival delay information of each of the received returning signals,
an electric power profile generator that generates electric power profiles for each arrival direction of the received returning signals and Doppler frequency component, using the generated correlation signals, and
a stationary object group distribution generator that, based on the generated electric power profiles, obtains a first distribution of Doppler frequency components of a stationary object group including a plurality of stationary objects as the plurality of targets in the perimeter of the moving object, for each azimuth angle.

2. The radar device according to claim 1 ,
wherein the stationary object group distribution generator includes
a traveling speed estimator that estimates the traveling speed of the moving object, based on the first distribution.

3. The radar device according to claim 2 ,
wherein the traveling speed estimator further estimates a rudder angle or yaw rate of the moving object.

4. The radar device according to claim 2 ,
wherein the stationary object group distribution generator further includes
a Doppler frequency distribution analyzer that counts an amount of the electric power profiles for each azimuth angle and each Doppler frequency components, that calculates the greatest amount of the electric power profiles at each azimuth angle, and that calculates Doppler frequency components where the amount of the electric power profiles is the greatest amount at each azimuth angle,
a stationary object group identifier that extracts the azimuth angle and the Doppler frequency components, where the greatest amount of the electric power profiles is a predetermined amount or greater, and
a motion state estimator that obtains the first distribution based on the extracted azimuth angle and the extracted Doppler frequency components.

5. The radar device according to claim 4 ,
wherein the stationary object group distribution generator further includes
a speed corrector that, based on the Doppler frequency components in the azimuth angle direction of the electric power profiles and the first distribution, corrects the relative speed of the electric power profiles exceeding a predetermined threshold value.

6. The radar device according to claim 2 ,
wherein the electric power profile generator outputs an electric power profile and Doppler frequency component profile corresponding to the distance and the azimuth angle of the stationary object group from the radar device.

7. The radar device according to claim 2 , further comprising:
a sensor that detects traveling speed of the moving object,
wherein the traveling speed estimator selects, as the traveling speed of the moving object, a detection value of the traveling speed of the moving object at the sensor, or an estimation value of the traveling speed of the moving object at the traveling speed estimator, in accordance with the first distribution.

8. The radar device according to claim 2 , further comprising:
a sensor that detects the traveling speed of the moving object,
wherein the traveling speed estimator selects, as the traveling speed of the moving object, a detection value of the traveling speed of the moving object at the sensor, or an estimation value of the traveling speed of the moving object at the traveling speed estimator, in accordance with whether or not the detection value of the traveling speed of the moving object at the sensor is at or above a predetermined speed.

9. The radar device according to claim 3 , further comprising:
a sensor that detects a traveling speed, and a rudder angle or yaw rate, of the moving object,
wherein the traveling speed estimator selects, as the traveling speed of the moving object, a detection value of the traveling speed of the moving object at the sensor, or an estimation value of the traveling speed of the moving object at the traveling speed estimator, in accordance with whether or not the moving object is traveling straight or curving.

10. The radar device according to claim 7 , further comprising:
a first correction coefficient calculator that obtains a first correction coefficient for correcting a difference between a detection value of the traveling speed of the moving object at the sensor, and the estimation value of the traveling speed of the moving object at the traveling speed estimator.

11. The radar device according to claim 9 , further comprising:
a second correction coefficient calculator that obtains
a first correction coefficient for correcting a difference between a detection value of the traveling speed of the moving object at the sensor, and the estimation value of the traveling speed of the moving object at the traveling speed estimator, and
a second correction coefficient for correcting a difference between a detection value of the rudder angle or yaw rate of the moving object at the sensor, and the estimation value of the rudder angle or yaw rate of the moving object at the traveling speed estimator.

12. The radar device according to claim 7 , further comprising:
a first operation change notifier that notifies operation change of the radar device, based on difference between a detection value of the traveling speed of the moving object at the sensor, and the estimation value of the traveling speed of the moving object at the traveling speed estimator.

13. The radar device according to claim 12 ,
wherein the first operation change notifier notifies operation change of the radar device, in a case where a rate of the difference between the detection value of the traveling speed of the moving object at the sensor and the estimation value of the traveling speed of the moving object at the traveling speed estimator being a first value or larger, is a second value or larger.

14. The radar device according to claim 2 , further comprising:
a transmission beam controller that outputs a control signal to switch a main beam direction of the radar transmission signals, at each predetermined number of transmission cycles,
wherein the radar transmitter transmits the radar transmission signals of which the main beam direction has been switched, based on the control signal.

15. The radar device according to claim 2 ,
wherein the radar transmitter transmits the radar transmission signals of which transmission code has been frequency modulated at each transmission cycle, from the transmission antenna,
and wherein the antenna brunch processors include each of
a mixer that outputs mixed signals of the returning signals received by the reception antennas and the frequency modulated radar transmission signals, at each transmission cycle of the radar transmission signals,
a filter that outputs a low-band frequency component of the mixed signals,
a Fourier transformer that transforms signals of the low-band frequency component into a frequency region, and
a Doppler frequency analyzer that performs coherent additio

Assignees

• Panasonic Corp

Inventors

• Kishigami Takaaki
• Nishimura Hirofumi

Classifications

• G01S13/26

  wherein the transmitted pulses use a frequency- or phase-modulated carrier wave · CPC title

• G01S13/931

  of land vehicles · CPC title

• G01S3/46

  using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems · CPC title

• G01S13/60 Primary

  wherein the transmitter and receiver are mounted on the moving object, e.g. for determining ground speed, drift angle, ground track (G01S13/64 takes precedence) · CPC title

• G01S13/42

  Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S13/46) · CPC title