Radar system

• US 8,334,802 B2
• Filed: 10/05/2009
• Issued: 12/18/2012
• 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
• Primary Examiner(s): GREGORY, BERNARR E
• Application Number:
  US12/573,383
• Publication Number:
  US 20100103023A1
• Time in Patent Office: 1,170 Days
• Field of Search: 342/27, 342/28, 342/59, 342 70- 72, 342/118, 342128-133, 342/175, 342192-197, 342 89-103, 701/300, 701/301
• US Class Current: 342/129
• 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 a first radio wave in accordance with one or more frequency modulation patterns;

a second radar that transmits a second radio 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 the first radio wave and the second radio wave do not continuously have a same frequency, wherein

the first radar and the second radar transmit the first radio wave and second radio wave, respectively, 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 in accordance with the first frequency modulation pattern, the other one of the first radar and the second radar transmits in accordance with the second frequency modulation pattern.

2. The radar system according to claim 1, wherein

the first frequency modulation pattern is a continuous wave mode, and

the second frequency modulation pattern is a frequency modulated continuous wave mode.

3. The radar system according to claim 2, wherein

the first frequency modulation pattern and the second frequency modulation pattern are set so that a transmission frequency of the continuous wave mode is not included in a transmission frequency band of the frequency modulated continuous wave mode.

4. The radar system according to claim 2, wherein

the first frequency modulation pattern and the second frequency modulation pattern are set so that a transmission frequency of the continuous wave mode coincides with an upper limit or a lower limit of a frequency band of the frequency modulated continuous wave 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 the transmission frequency of the continuous wave mode does not coincide with a transmission frequency of the frequency modulated continuous wave mode in such a manner that a continuous transmission time of a radio wave in the continuous wave mode is shorter than a continuous transmission time of a radio wave in the frequency modulated continuous wave mode.

6. The radar system according to claim 2, wherein

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

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

7. The radar system according to claim 2, wherein

during a time period when a frequency output from the first radar in the frequency modulated continuous wave mode is higher than a predetermined frequency, the second radar outputs a frequency lower than the predetermined frequency, and

during a time period when the frequency output from the first radar in the frequency modulated continuous wave mode is lower than the predetermined frequency, the second radar outputs a frequency higher than the predetermined frequency.

8. The radar system according to claim 2, wherein

a frequency band of the frequency modulated continuous wave mode is wider than a frequency band of the continuous wave mode.

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

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

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

controlling the first radar and the second radar to transmit the first radio wave and second radio wave, respectively, by alternately switching between a first frequency modulation pattern and a second frequency modulation pattern that is different from the first frequency modulation pattern so that the first radio wave and the second radio wave do not continuously have a same frequency,

wherein the first radar and the second radar are controlled so that, while one of the first radar and the second radar is transmitting in accordance with the first frequency modulation pattern, the other one of the first radar and the second radar transmits in accordance with the second frequency modulation pattern.

10. The method of controlling a radar system according to claim 9, wherein

the first frequency modulation pattern is a continuous wave mode,

the second frequency modulation pattern is a frequency modulated continuous wave mode, and

the first frequency modulation pattern and the second frequency modulation pattern are controlled so that a transmission frequency of the continuous wave mode is not included in a transmission frequency band of the frequency modulated continuous wave mode.

11. The method of controlling a radar system according to claim 9, wherein

the first frequency modulation pattern is a continuous wave mode,

the second frequency modulation pattern is a frequency modulated continuous wave mode, and

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