RADAR APPARATUS

• US 20150123840A1
• Filed: 02/13/2014
• Published: 05/07/2015
• Est. Priority Date: 02/26/2013
• Status: Active Grant

• Current Assignee: Panasonic Automotive Systems Company of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Morita, Tadashi, Kishigami, Takaaki
• Granted Patent: US 9,405,003 B2
• Time in Patent Office: Days
• US Class Current: 342/175
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/02 Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
• CPC Class Codes: G01S 13/284 using coded pulses
• CPC Class Codes: G01S 7/02 of systems according to group G01S13/00
• CPC Class Codes: G01S 7/292 Extracting wanted echo-signals

Abstract

A transmission signal generating unit generates a transmission signal by multiplying one (selected in prescribed order) of 2^N+1 (N: an integer of 1 or more) codes of a Spano code sequence by one code (selected in prescribed order), having a length 1, of one of a first code or a second code each having a code length 2^N+1 in every transmission cycle. A transmission RF unit converts the transmission signal into a radio-frequency radar transmission signal and transmits it from a transmission antenna. As for codes used in adjacent two transmission cycles for two times 2^N+1 transmission cycles, the sum total of inner products of codes having a length 1 of the first code, inner products of codes having a length 1 of the second code, and inner products of codes of the first code and the second code becomes equal to 0.

Claims

1. A radar apparatus comprising:

a transmission signal generating unit which sequentially generates transmission signals containing 2×

M×

2^N+1 first multiplied codes by

multiplying 2^N+1 (N;

an integer that is larger than or equal to

     1) codes contained in M (M;

an integer that is larger than or equal to

     1) kinds of Spano code sequences by respective elements of a first multiplication code sequence having a code length 2^N+1 in respective transmission cycles, and

multiplying the 2^N+1 codes of the M kinds of Spano code sequences by respective elements of a second multiplication code sequence having a code length 2^N+1 in the respective transmission cycles; and

a transmission RF unit which converts the transmission signals into radio-frequency radar transmission signals and transmits the radio-frequency radar transmission signals from a transmission antenna,

wherein the first multiplication code sequence and the second multiplication code sequence are code sequences that satisfy Equation (1);

2. The radar apparatus according to claim 1,

wherein the transmission signal generating unit comprises:

a transmission code storage unit which stores the M kinds of Spano code sequences;

a multiplication codes storage unit which stores the first multiplication code sequence and the second multiplication code sequence; and

a multiplication code multiplying unit which multiplies 2^N+1 codes contained in a first Spano code sequence of the M kinds of Spano code sequences by the respective elements of the first multiplication code sequence or the second multiplication code sequence in the respective transmission cycles.

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

a reception RF unit which receives, by a reception antenna, reflection wave signals produced as a result of reflection of the radar transmission signals by a target, and generates baseband reception signals;

a correlation calculating unit which calculates sets of correlation values between the reception signals and the transmission signals containing the first multiplied codes generated by multiplication by the elements of the first multiplication code sequence or the second multiplication code sequence; and

a coherent addition unit which adds up sets of correlation values calculated over 2×

M×

2^N+1 transmission cycles.

4. The radar apparatus according to claim 1,

wherein N is equal to 2,

wherein the first multiplication code sequence is [1, 1, 1, 1, 1, 1, 1, 1], and

wherein the second multiplication code sequence is [−

1, 1, −

1, 1, −

1, 1, −

1, 1].

5. The radar apparatus according to claim 1,

wherein N is equal to 2,

wherein the first multiplication code sequence is [1, 1, −

1, −

1, 1, 1, −

1, −

1], and

wherein the second multiplication code sequence is [1, −

1, −

1, 1, 1, −

1, −

1, 1].

6. The radar apparatus according to claim 1,

wherein N is equal to 1,

wherein the first multiplication code sequence is [1, 1, 1, 1], and

wherein the second multiplication code sequence is [−

1, 1, −

1, 1].

7. The radar apparatus according to claim 1,

wherein N is equal to 1,

wherein the first multiplication code sequence is [1, 1, 1, 1], and

wherein the second multiplication code sequence is [1, −

1, 1, −

1].

8. The radar apparatus according to claim 1,

wherein N is equal to 1,

wherein the first multiplication code sequence is [1, 1, −

1, −

1], and

wherein the second multiplication code sequence is [1, −

1, −

1, 1].

9. The radar apparatus according to claim 2,

wherein the transmission signals generated by the transmission signal generating unit contain:

2×

M×

2^N+1 second multiplied codes generated by multiplying the first multiplied codes by a first multiplication code coefficient SZ11 and generated by multiplying the first multiplied codes by a first multiplication code coefficient SZ11 by a second multiplication code coefficient SZ12 in units of 2^N+1 first multiplied codes, and

2×

M×

2^N+1 third multiplied codes generated by multiplying the first multiplied codes by a third multiplication code coefficient SZ21 and generated by multiplying the first multiplied codes by a fourth multiplication code coefficient SZ22 in units of 2^N+1 first multiplied codes,

wherein the multiplication code coefficients SZ11, SZ12, SZ21, and SZ22 satisfies Equation (2);

SZ11·

SZ12=−

SZ21·

SZ22  

 

(2)

10. The radar apparatus according to claim 9,

wherein the multiplication codes storage unit further stores the first multiplication code coefficient, the second multiplication code coefficient, the third multiplication code coefficient, and the fourth multiplication code coefficient.

11. The radar apparatus according to claim 9, further comprising:

a reception RF unit which receives, by a reception antenna, reflection wave signals produced as a result of reflection of the radar transmission signals by a target, and generates baseband reception signals;

a correlation calculating unit which calculates sets of correlation values between the reception signals and the second multiplied codes or the third multiplied codes; and

a coherent addition unit which adds up sets of correlation values calculated over four times 2×

M×

2^N+1 transmission cycles.

12. The radar apparatus according to claim 9,

wherein N is equal to 2,

wherein the first multiplication code sequence is [1, 1, 1, 1, 1, 1, 1, 1],

wherein the second multiplication code sequence is [−

1, 1, −

1, 1, −

1, 1, −

1, 1],

wherein the first multiplication code coefficient is “

1,”

wherein the second multiplication code coefficient is “

1,”

wherein the third multiplication code coefficient is “

1,” and

wherein the fourth multiplication code coefficient is “

−

1.”

13. The radar apparatus according to claim 9,

wherein N is equal to 2,

wherein the first multiplication code sequence is [1, 1, −

1, −

1, 1, 1, −

1, −

1],

wherein the second multiplication code sequence is [1, −

1, −

1, 1, 1, −

1, −

1, 1],

wherein the first multiplication code coefficient is “

1,”

wherein the second multiplication code coefficient is “

1,”

wherein the third multiplication code coefficient is “

1,” and

wherein the fourth multiplication code coefficient is “

−

1.”

14. The radar apparatus according to claim 9,

wherein N is equal to 1,

wherein the first multiplication code sequence is [1, 1, 1, 1],

wherein the second multiplication code sequence is [−

1, 1, −

1, 1], and

wherein for each set of 2×

M×

2^N+1 codes,

the first multiplication code coefficient is “

1,”

the second multiplication code coefficient is “

1,”

the third multiplication code coefficient is “

1,” and

the fourth multiplication code coefficient is “

−

1.”

15. The radar apparatus according to claim 9,

wherein N is equal to 1,

wherein the first multiplication code sequence is [1, 1, 1, 1],

wherein the second multiplication code sequence is [1, −

1, 1, −

1], and

wherein the first multiplication code coefficient is “

1,”

wherein the second multiplication code coefficient is “

1,”

wherein the third multiplication code coefficient is “

1,” and

wherein the fourth multiplication code coefficient is “

−

1.”

16. The radar apparatus according to claim 9,

wherein N is equal to 1,

wherein the first multiplication code sequence is [1, 1, −

1, −

1],

wherein the second multiplication code sequence is [1, −

1, −

1, 1], and

wherein the first multiplication code coefficient is “

1,”

wherein the second multiplication code coefficient is “

1,”

wherein the third multiplication code coefficient is “

1,” and

wherein the fourth multiplication code coefficient is “

−

1.”