Radar apparatus

• US 9,500,741 B2
• Filed: 12/26/2014
• Issued: 11/22/2016
• Est. Priority Date: 01/15/2014
• Status: Active Grant

• Current Assignee: Panasonic Automotive Systems Company of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Kishigami, Takaaki, Nakagawa, Yoichi
• Primary Examiner(s): Sotomayor, John B
• Application Number:
  US14/583,364
• Publication Number:
  US 20150198697A1
• Time in Patent Office: 697 Days
• Field of Search: 342145-147, 342107-108, 342113-114, 342/133, 342/139, 342/192, 342/196, 342 70- 72
• US Class Current: 1/1
• CPC Class Codes: G01S 13/26 wherein the transmitted pulses use a frequency- or phase-modulated carrier wave
• CPC Class Codes: G01S 13/325 using transmission of coded signals, e.g. P.S.K. signals
• CPC Class Codes: G01S 13/343 using sawtooth modulation
• CPC Class Codes: G01S 13/582 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 2013/93274 on the side of the vehicles
• CPC Class Codes: G01S 7/2813 Means providing a modification of the radiation pattern for cancelling noise, clutter or interfering signals, e.g. side lobe suppression, side lobe blanking, null-steering arrays specially adapted to secondary radar systems G01S13/762; aerials or aerials systems H01Q21/29, H01Q25/00
• CPC Class Codes: G01S 7/2886 using I/Q processing
• CPC Class Codes: G01S 7/2923 based on data belonging to a number of consecutive radar periods
• CPC Class Codes: G01S 7/411 Identification of targets based on measurements of radar reflectivity G01S7/415 takes precedence
• CPC Class Codes: G01S 7/414 Discriminating targets with respect to background clutter
• CPC Class Codes: G01S 7/415 Identification of targets based on measurements of movement associated with the target

Abstract

A radar apparatus is installed in a vehicle that moves along its direction of travel. A radar transmission unit transmits a high frequency radar transmission signal from a transmit antenna in each transmit period. In a radar reception unit, antenna system processing units each generate a correlation vector by computing the correlation between reflected wave signal from a stationary object or a moving object and the radar transmission signal. A Doppler frequency-azimuth conversion unit converts Doppler frequencies into the components of an azimuth in which the stationary object is present using an estimated vehicle speed vector for the vehicle. A stationary object azimuth estimation unit generates the power profile of the reflected wave signal using the correlation vector and a direction vector corresponding to the components of the azimuth in which the stationary object is present.

Claims

1. A radar apparatus for installation in a mobile unit, comprising:

a radar transmission unit that transmits a radar transmission signal in a high frequency band from a transmit antenna in each transmit period; and

a radar reception unit that receives a reflected wave signal resulting from the radar transmission signal being reflected off one or more stationary objects or one or more moving objects with each of a plurality of receive antennas,

wherein the radar reception unit includes

a plurality of antenna system processing units that each generate a correlation signal including arrival delay information for the reflected wave signal by computing a correlation between the reflected wave signal and the radar transmission signal and that output information based on a first plurality of Doppler frequencies contained in the correlation signal;

a Doppler frequency-azimuth conversion unit that converts a second plurality of Doppler frequencies estimated frequencies caused by the stationary objects into a first azimuth component in accordance with movement information for the mobile unit in same frequency as the first plurality of Doppler frequencies; and

a stationary object azimuth estimation unit that generates a first power profile for a first predetermined range including an azimuth in which the present of stationary object is estimated using the result of computation based on the information of the first plurality of Doppler frequencies and the first azimuth component.

2. The radar apparatus according to claim 1, further comprising:

a stationary object detection unit that outputs a Doppler frequency and an azimuth that make the first power profile equal to or higher than a first predetermined threshold value as detection information for the stationary objects present.

3. The radar apparatus according to claim 1, further comprising:

a moving object azimuth estimation unit that generates a second power profile for a second predetermined range not including the first azimuth component using the information based on the first plurality of Doppler frequencies.

4. The radar apparatus according to claim 3, further comprising:

a moving object detection unit that outputs a Doppler frequency and an azimuth that make the second power profile equal to or higher than a second predetermined threshold value as detection information for the moving object present.

5. The radar apparatus according to claim 1, further comprising:

a moving status estimation unit that computes the movement information for the mobile unit using by a sensor.

6. The radar apparatus according to claim 1,

wherein the antenna system processing units each include

a correlation computation unit that computes a correlation value between the reflected wave signal and the radar transmission signal in each transmit period of the radar transmission signal;

a first coherent addition unit that performs coherent addition of correlation values over a first predetermined number of transmit periods and outputs the results of first coherent additions; and

a second coherent addition unit that corrects a phase variation of the results of first coherent additions occurring in correspondence to each of the first plurality of Doppler frequencies, and performs coherent addition of the results of correction over a second predetermined number of transmit periods, and outputs the results of second coherent additions as the information based on the first plurality of Doppler frequencies contained in the correlation signal.

7. The radar apparatus according to claim 1,

wherein the radar transmission unit transmits the radar transmission signal generated by frequency modulation of a transmission code from the transmit antenna in each transmit period, and

wherein the antenna system processing units each include

a mixer unit that combines the reflected wave signal with the radar transmission signal in each transmit period;

a filter unit that outputs a low frequency component of the combined signal;

a Fourier transform unit that converts the low frequency component signal into a frequency domain; and

a Doppler frequency analysis unit that corrects a phase variation of signals converted to the frequency domain occurring in correspondence to each of the first plurality of Doppler frequencies for each frequency component, and performs coherent addition of correction, and outputs a result of third coherent additions as the information based on the first plurality of Doppler frequencies.

8. The radar apparatus according to claim 1, wherein the azimuth components included in the first predetermined range include ±

45°

or ±

135°

directions relative to a front direction of the mobile unit.

9. The radar apparatus according to claim 3, wherein the azimuth components included in the second predetermined range include ±

45°

or ±

135°

directions relative to the front direction of the mobile unit.