RADAR SYSTEM

• US 20100103023A1
• Filed: 10/05/2009
• Published: 04/29/2010
• Est. Priority Date: 10/28/2008
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: OGAWA, Masaru
• Granted Patent: US 8,334,802 B2
• Time in Patent Office: Days
• US Class Current: 342/59
• CPC Class Codes: G01S 13/345 using triangular modulation
• CPC Class Codes: G01S 13/347 using more than one modulation frequency
• CPC Class Codes: G01S 13/348 using square or rectangular modulation, e.g. diplex radar for ranging over short distances
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• 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 2013/93275 in the bumper area
• CPC Class Codes: G01S 7/023 Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36
• CPC Class Codes: G01S 7/0232 Avoidance by frequency multiplex
• CPC Class Codes: G01S 7/0233 Avoidance by phase multiplex

Abstract

A radar system includes radars and a controller. The controller controls waveform patterns of the radars. As a signal processing unit of each of the radars receives an instruction from the controller, the signal processing unit selects a frequency modulation pattern of a VCO between an FM-CW mode and a CW mode stored in a waveform memory to perform mode switching, and then outputs a radio wave from a transmission antenna. Then, the controller instructs each signal processing unit for a frequency modulation pattern of each radar or an output timing of each pattern so that a time, at which continuous wave signals output from the radars have the same frequency, is not continuous.

Claims

1. A radar system comprising:

a first radar that transmits an electromagnetic wave in accordance with one or more frequency modulation patterns;

a second radar that transmits an electromagnetic wave in accordance with one or more frequency modulation patterns; and

a controller that controls the first radar and the second radar to detect a surrounding obstacle so that a time, at which the electromagnetic waves output respectively from the first radar and the second radar at the same time have the same frequency, is not continuous.

2. The radar system according to claim 1, wherein

the controller differentiates the frequency modulation pattern used in the first radar from the frequency modulation pattern used in the second radar.

3. The radar system according to claim 2, wherein

the first radar and the second radar each transmit an electromagnetic wave by alternately switching between a first frequency modulation pattern and a second frequency modulation pattern that is different from the first frequency modulation pattern, and

the controller controls the first radar and the second radar so that, while one of the first radar and the second radar is transmitting an electromagnetic wave in accordance with the first frequency modulation pattern, the other one of the first radar and the second radar transmits an electromagnetic wave in accordance with the second frequency modulation pattern.

4. The radar system according to claim 3, wherein

the first frequency modulation pattern is a CW mode, and

the second frequency modulation pattern is an FM-CW mode.

5. The radar system according to claim 4, wherein

the first frequency modulation pattern and the second frequency modulation pattern are set so that a transmission frequency of the CW mode is not included in a transmission frequency band of the FM-CW mode.

6. The radar system according to claim 4, wherein

the first frequency modulation pattern and the second frequency modulation pattern are set so that a transmission frequency of the CW mode coincides with an upper limit or lower limit of a frequency band of the FM-CW mode.

7. The radar system according to claim 4, wherein

the first frequency modulation pattern is a dual-frequency CW mode that alternately uses two transmission frequencies, and

the controller causes a timing, at which a transmission frequency of the CW mode coincides with a transmission frequency of the FM-CW mode, to coincide with a timing at which a transmission frequency of the dual-frequency CW mode is switched.

8. The radar system according to claim 6, wherein

the first frequency modulation pattern and the second frequency modulation pattern are set so that a transmission frequency of the CW mode does not coincide with a transmission frequency of the FM-CW mode in such a manner that a continuous transmission time of an electromagnetic wave in the CW mode is shorter than a continuous transmission time of an electromagnetic wave in the FM-CW mode.

9. The radar system according to claim 4, wherein

during a time period when a frequency output from the first radar in the FM-CW mode is higher than a predetermined frequency, the second radar outputs a frequency lower than the predetermined frequency, and

during a time period when a frequency output from the first radar in the FM-CW mode is lower than the predetermined frequency, the second radar outputs a frequency higher than the predetermined frequency.

10. The radar system according to claim 4, wherein

a frequency band of the FM-CW mode is wider than a frequency band of the CW mode.

11. The radar system according to claim 1, wherein

a frequency modulation pattern used in the first radar and a frequency modulation pattern used in the second radar are the same frequency modulation pattern, and

the controller differentiates mutual phases of electromagnetic waves transmitted respectively from the first radar and the second radar in accordance with the same frequency modulation pattern.

12. The radar system according to claim 11, wherein

the same frequency modulation pattern is an FM-CW mode.

13. The radar system according to claim 12, wherein

the controller controls the first radar and the second radar so that, while a frequency of an electromagnetic wave transmitted from one of the first radar and the second radar is monotonously increasing, a frequency of an electromagnetic wave transmitted from the other one of the first radar and the second radar monotonously decreases.

14. A method of controlling a radar system that detects a surrounding obstacle, comprising:

transmitting a first electromagnetic wave in accordance with one or more frequency modulation patterns;

transmitting a second electromagnetic wave in accordance with one or more frequency modulation patterns; and

controlling the first and second electromagnetic waves so that a time, at which frequencies of the first and second electromagnetic waves become the same frequency, is not continuous.