# US 2016/0259042 A1 · Radar apparatus

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- Number: US 2016/0259042 A1
- Document ID: US20160259042A1
- Status: Published application
- Kind: A1
- Application number: 15/045,338
- Filed: 2016-02-17
- Published: 2016-09-08
- Earliest claimed: 2015-03-03
- Assignees: Panasonic Corporation
- Applicants: Panasonic Corporation
- Inventors: TAKAAKI KISHIGAMI; NORIAKI TAKEDA
- Web page: https://patentgrep.com/patent/US20160259042A1

## CPC

- G01S 13/284: {using coded pulses}
- G01S 7/038: {Feedthrough nulling circuits}
- G01S 7/288: Coherent receivers
- G01S 13/106: {using transmission of pulses having some particular characteristics (G01S13/12, G01S13/22, G01S13/24, G01S13/26, G01S13/28 and G01S13/30 take precedence)}
- G01S 13/288: {phase modulated}
- G01S 7/2886: {using I/Q processing}
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES

## Abstract

A radar apparatus includes: a transmitter which, in operation, transmits, as radar transmission signals, code sequences including a plurality of complementary codes having a code length L in each transmission period; a receiver which, in operation, receives one or more reflected waves including the radar transmission signals reflected by an object and are analog signals; an A/D converter which, in operation, converts the one or more reflected signals into digital signals, which are discrete samples; and a calculator which, in operation, performs a first calculation of correlation between the discrete samples and the code sequence transmitted by the transmitter and a second calculation of correlation between the discrete samples and a partial code sequence obtained by extracting a code length L−Q (L>Q≧2) from a tail end of the code sequence transmitted by the transmitter, and that outputs one of a result of the first correlation calculation and a result of the second correlation calculation.

## Claims

### Claim 1

A radar apparatus comprising:
a transmitter which, in operation, transmits, as radar transmission signals, code sequences including a plurality of complementary codes having a code length L in each transmission period;
a receiver which, in operation, receives one or more reflected waves including the radar transmission signals reflected by an object and are analog signals;
an analog-to-digital (A/D) converter which, in operation, converts the one or more reflected signals into digital signals, which are discrete samples; and
a calculator which, in operation, performs a first calculation of correlation between the discrete samples and the code sequence transmitted by the transmitter and a second calculation of correlation between the discrete samples and a partial code sequence obtained by extracting a code length L−Q (L>Q≧2) from a tail end of the code sequence transmitted by the transmitter, and that outputs one of a result of the first correlation calculation and a result of the second correlation calculation.

### Claim 2 (depends on 1)

The radar apparatus according to claim 1,
wherein the code sequence includes 2L complementary codes, and
the transmitter transmits the 2L complementary codes in a predetermined number of transmission periods.

### Claim 3 (depends on 1)

The radar apparatus according to claim 1,
wherein the code sequence satisfies expressions (1) and (2):
RS
S
1
:
S
2

(
τ
,
A

(
1
)
,
A

(
2


L
)
)
=
∑
m
=
1
2


L


∑
n
=
S
1
S
2


a

(
m
)
n
+
τ

a

(
m
)
n
*
(
1
)
{
RS
S
1
:
S
2

(
τ
,
A

(
1
)
,
A

(
2


L
)
)
≠
0
,
when


τ
=
0
RS
S
1
:
S
2

(
τ
,
A

(
1
)
,
A

(
2


L
)
)
=
0
,
when


τ
≠
0
(
2
)
wherein an m-th code sequence is a code sequence A(m) having the code length L and is represented by A(m)={a(m)1, a(m)2, . . . , a(m)L}, where m=1, . . . , 2L, S2−S1+1≧2, L>S2>S1, and τ represents a delay during the correlation calculation.

### Claim 4 (depends on 1)

The radar apparatus according to claim 1,
wherein the code sequence is a Spano code sequence.

### Claim 5 (depends on 1)

The radar apparatus according to claim 1,
wherein the calculator comprises:
a first correlation calculator which, in operation, performs the first correlation calculation;
a second correlation calculator which, in operation, performs the second correlation calculation; and
a switch which, in operation, selects the result of the first correlation calculation from k to k+Q+1 on discrete times and selects the result of the second correlation calculation from k+Q+1 to L on the discrete times, k is an integer, when a timing at which the correlation calculator starts to performs the first correlation calculation is the discrete times k.

### Claim 6 (depends on 1)

The radar apparatus according to claim 1,
wherein the calculator comprises:
a coefficient controller which, in operation, varies multiplication coefficients at respective discrete times k, k is an integer, the multiplication coefficients being used on correlation with the discrete samples converted by the A/D converter.