RADAR APPARATUS

• US 20150061915A1
• Filed: 11/07/2012
• Published: 03/05/2015
• Est. Priority Date: 11/17/2011
• Status: Active Grant

• Current Assignee: Panasonic Automotive Systems Company of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Kishigami, Takaaki, Mukai, Hirohito
• Granted Patent: US 9,733,347 B2
• Time in Patent Office: Days
• US Class Current: 342/27
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/04 Systems determining presence of a target based on relative movement of target G01S13/56
• CPC Class Codes: G01S 13/222 using random or pseudorandom pulse repetition frequency
• CPC Class Codes: G01S 13/288 phase modulated
• CPC Class Codes: G01S 13/91 for traffic control G01S13/93 takes precedence
• CPC Class Codes: G01S 7/02 of systems according to group G01S13/00
• 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

Abstract

A radar transmitter Tx_s (s=1) generates a baseband transmission signal by modulating a first code sequence having a prescribed code length on the basis of a first transmission timing signal and gives a first transmission phase shift corresponding to each transmission cycle to the transmission signal. A radar receiver Tx_s (s=2) generates a baseband transmission signal by modulating a second code sequence having the prescribed code length on the basis of a second transmission timing signal and gives, to the transmission signal, a second transmission phase shift that correspond to each transmission cycle and opposite to the first transmission phase.

Claims

1. A radar apparatus comprising:

a first radar transmitter that transmits a first radar transmission signal generated using a first code sequence having a prescribed code length from a first transmission antenna as a first radio-frequency signal; and

a second radar transmitter that transmits a second radar transmission signal generated using a second code sequence having a prescribed code length from a second transmission antenna as a second radio-frequency signal, wherein;

the first radar transmission signal is a signal generated by modulating the first code sequence that has been phase-shifted on the basis of a first transmission timing signal;

the second radar transmission signal is a signal generated by modulating the second code sequence that has been phase-shifted on the basis of a second transmission timing signal; and

a phase shift given to the first code sequence is opposite to a phase shift given to the second code sequence.

2. The radar apparatus according to claim 1, wherein the first radar transmitter comprises:

a first pulse transmission controller that generates the first transmission timing signal every transmission cycle;

a first radar code generater that generates the first code sequence;

a first modulater that generates a first baseband signal by modulating the first code sequence on the basis of the first transmission timing signal;

a first transmission phase shifter that shifts the phase of the first baseband signal on the basis of the first transmission timing signal; and

a first RF transmitter that converts the phase-shifted first baseband signal into the radio-frequency first radar transmission signal and transmits the radio-frequency first radar transmission signal from the first transmission antenna.

3. The radar apparatus according to claim 2, wherein:

the first radar code generater comprises;

a first code generater that generates a transmission code of a third code sequence that is a complementary code sequence having a prescribed code length on the basis of the first transmission timing signal generated every odd-numbered transmission cycle; and

a second code generater that generates a transmission code of a fourth code sequence that is a complementary code sequence having the prescribed code length on the basis of the first transmission timing signal generated every even-numbered transmission cycle;

the first code sequence consists of the third code sequence and the fourth code sequence; and

the first transmission phase shifter gives a phase shift corresponding to two transmission cycles.

4. The radar apparatus according to claim 1, wherein the second radar transmitter comprises:

a second pulse transmission controller that generates the second transmission timing signal every transmission cycle;

a second radar code generater that generates the second code sequence;

a second modulater that generates a second baseband signal by modulating the second code sequence on the basis of the second transmission timing signal;

a second transmission phase shifter that shifts the phase of the second baseband signal on the basis of the second transmission timing signal; and

a second RF transmitter that converts the phase-shifted second baseband signal into the radio-frequency second radar transmission signal and transmitting the radio-frequency second radar transmission signal from the second transmission antenna.

5. The radar apparatus according to claim 4, wherein:

the second radar code generater comprises;

a third code generater that generates a transmission code of a fifth code sequence that is a complementary code sequence having a prescribed code length on the basis of the second transmission timing signal generated every odd-numbered transmission cycle; and

a fourth code generater that generates a transmission code of a sixth code sequence that is a complementary code sequence having the prescribed code length on the basis of the second transmission timing signal generated every even-numbered transmission cycle;

the second code sequence consists of the fifth code sequence and the sixth code sequence; and

the second transmission phase shifter gives a phase shift corresponding to two transmission cycles.

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

a first radar receiver that detects presence/absence of a target on the basis of a reflection wave signal that is produced through reflection of the radio-frequency first radar transmission signal by the target, the first radar receiver comprising;

a first RF receiver that receives the reflection wave signal by a first reception antenna and converts the received reflection wave signal into a baseband first reception signal;

a first reception phase shifter that gives an opposite phase shift that is opposite to the first phase shift given by the first transmission phase shifter to the first reception signal supplied from the first RF receiver on the basis of the first transmission timing signal;

a first correlation value calculator that calculates correlation values between the opposite-phase-shift-given first reception signal and the first transmission code; and

a first coherent integrator that adds together correlation values calculated by the first correlation value calculator in a prescribed number of transmission cycles.

7. The radar apparatus according to claim 6, further comprising:

a second radar receiver that detects presence/absence of the target on the basis of a reflection wave signal that is produced through reflection of the radio-frequency second radar transmission signal by the target, the second radar receiver comprising;

a second RF receiver that receives the reflection wave signal by a second reception antenna and converts the received reflection wave signal into a baseband second reception signal;

a second reception phase shifter that gives an opposite phase shift that is opposite to the second phase shift given by the second transmission phase shifter to the second reception signal supplied from the second RF receiver on the basis of the second transmission timing signal;

a second correlation value calculator that calculates correlation values between the opposite-phase-shift-given second reception signal and the second transmission code; and

a second coherent integrator that adds together correlation values calculated by the second correlation value calculator in a prescribed number of transmission cycles.

8. The radar apparatus according to claim 7, wherein:

the first radar receiver further comprises;

a first VGA unit that adjusts an output level of the first reception signal supplied from the first RF receiver; and

a first A/D converter that converts an analog first reception signal whose output level has been adjusted by the first VGA unit into a digital first reception signal; and

the second radar receiver further comprises;

a second VGA unit that adjusts an output level of the second reception signal supplied from the second RF receiver; and

a second A/D converter that converts an analog first reception signal whose output level has been adjusted by the second VGA unit into a digital second reception signal.

9. The radar apparatus according to claim 6, wherein:

the first radar receiver further comprises a first distance estimator that estimates a distance to the target on the basis of correlation value addition results supplied from the first coherent integrator; and

the second receiver further comprises a second distance estimator that estimates a distance to the target on the basis of correlation value addition results supplied from the second coherent integrator.

10. The radar apparatus according to claim 6, wherein the third, fourth, fifth, and sixth code sequences are the same code sequence and have the same code length.

11. The radar apparatus according to claim 6, wherein the third, fourth, fifth, and sixth code sequences are different code sequences and have the same code length.

12. The radar apparatus according to claim 6, wherein the third code sequence or the fourth code sequence has a different code length than the fifth code sequence or the sixth code sequence.

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

a third radar transmitter that generates a third baseband signal using a seventh code sequence having the prescribed code length on the basis of the first transmission timing signal, shifting the phase of the third baseband signal on the basis of the first transmission timing signal, converting the phase-shifted third baseband signal into a radio-frequency third radar transmission signal, and transmitting the latter from a third transmission antenna; and

a fourth radar transmitter that generates a fourth baseband signal using an eighth code sequence having the prescribed code length on the basis of the second transmission timing signal, shifting the phase of the fourth baseband signal on the basis of the second transmission timing signal, converting the phase-shifted fourth baseband signal into a radio-frequency fourth radar transmission signal, and transmitting the latter from a fourth transmission antenna, wherein;

the phase shift given to the third baseband signal is opposite to the phase shift given to the fourth baseband signal;

the phase shift given to the first baseband signal is opposite to the phase shift given to the third baseband signal; and

the phase shift given to the second baseband signal is opposite to the phase shift given to the fourth baseband signal.

14. The radar apparatus according to claim 1, wherein:

a phase shift of 90°

is given in the first radar transmitter; and

a phase shift of −

90°

is given in the second radar transmitter.

15. The radar apparatus according to claim 11, wherein sums of cross-correlation values between the third code sequence and the fifth code sequence and cross-correlation values between the fourth code sequence and the sixth code sequence are equal to zero.