Detection device, detection method, and detection program

1. A detection device, comprising:

a first correlation circuit that computes correlation of a first wave detection signal which is a phase-modulated input wave detected at a determined frequency with a determined code sequence for every code composing the determined code sequence, and generates a plurality of first correlation signals the number of which corresponds to a code sequence length, which is a length of the determined code sequence; and

a control circuit that rotates phases of the plurality of first correlation signals, generates an added value by adding the phase-rotated plurality of first correlation signals, and determines based on the added value whether the phase-modulated input wave is a return wave from a determined object, wherein:

the first wave detection signal includes an I signal component and a Q signal component, which are obtained by performing quadrature detection on the phase-modulated input wave,

the first correlation circuit computes correlation of the I signal component of the first wave detection signal and the Q signal component of the first wave detection signal with the determined code sequence for every code composing the determined code sequence, and generates an I signal component of the plurality of first correlation signals and a Q signal component of the plurality of first correlation signals, and

the control circuit includes a phase rotation control circuit which rotates phases of the I signal component of the plurality of first correlation signals and a phase rotation control circuit which rotates phases of the Q signal component of the plurality of first correlation signals, generates an I signal component of the added value by adding the I signal component of the phase-rotated plurality of first correlation signals and a Q component signal of the added value by adding the Q signal component of the phase-rotated plurality of first correlation signals, and the control circuit determines based on the I signal component of the added value and the Q signal component of the added value whether the phase-modulated input wave is the return wave from the determined object.

2. The detection device according to claim 1 , wherein:

the phase-modulated input wave is generated by phase-modulating a carrier wave using the determined code sequence, and

the determined frequency is a frequency of the carrier wave.

3. The detection device according to claim 1 , which is a single-chip integrated circuit.

4. A detection device comprising:

a first correlation circuit that computes correlation of a first wave detection signal which is a phase-modulated input wave detected at a determined frequency with a determined code sequence for every code composing the determined code sequence, and generates a plurality of first correlation signals the number of which corresponds to a code sequence length, which is a length of the determined code sequence; and

a control circuit that rotates phases of the plurality of first correlation signals, generates an added value by adding the phase-rotated plurality of first correlation signals, and determines based on the added value whether the phase-modulated input wave is a return wave from a determined object,

wherein the control circuit includes:

a plurality of phase control circuits that rotate phases of the first correlation signals by determined amounts based on a plurality of different amounts of a Doppler shift, and generate added values by adding the phase-rotated first correlation signals,

a plurality of first strength acquisition circuits that are provided corresponding to the plurality of phase control circuits, and, based on the added values generated by the corresponding phase control circuits, derive a plurality of pieces of first strength information indicating strength of the phase-modulated input wave,

a unification circuit that selects one from the plurality of pieces of first strength information, and

a detection circuit that determines whether the phase-modulated input wave is the return wave from the determined object.

5. The detection device according to claim 4 , wherein

the determined amounts based on the amounts of the Doppler shift are any one of 0°, 90°, 180°, or 270°.

6. A detection device comprising:

a first correlation circuit that computes correlation of a first wave detection signal which is a phase-modulated input wave detected at a determined frequency with a determined code sequence for every code composing the determined code sequence, and generates a plurality of first correlation signals the number of which corresponds to a code sequence length, which is a length of the determined code sequence;

a control circuit that rotates phases of the plurality of first correlation signals, generates an added value by adding the phase-rotated plurality of first correlation signals, and determines based on the added value whether the phase-modulated input wave is a return wave from a determined object;

a second wave detection circuit that detects, by a signal of a frequency different from that of a carrier wave, an input wave from outside of the detection device and generates a second wave detection signal which detects the input wave; and

a second correlation circuit that computes correlation of the second wave detection signal with the determined code sequence for every code composing the code sequence and generates a single second correlation signal,

wherein the control circuit includes a detection circuit that determines based on the added value and the second correlation signal whether the determined object is present within a detection area of the detection device.

7. A detection method performed by a detection device, comprising:

computing, by the detection device, correlation of a first wave detection signal, which is a phase-modulated input wave detected at a determined frequency, with a determined code sequence for every code composing the determined code sequence;

generating, by the detection device, a plurality of first correlation signals the number of which corresponds to a code sequence length, which is a length of the determined code sequence;

rotating, by the detection device, phases of the plurality of first correlation signals;

generating, by the detection device, an added value by adding the phase-rotated plurality of first correlation signals; and

determining, by the detection device, based on the added value whether the phase-modulated input wave is a return wave from a determined object, wherein:

the first wave detection signal includes an I signal component and a Q signal component, which are obtained by performing quadrature detection on the phase-modulated input wave,

the computing of the correlation of the first wave detection signal includes computing correlation of the I signal component of the first wave detection signal and the Q signal component of the first wave detection signal with the determined code sequence for every code composing the determined code sequence, and generating an I signal component of the plurality of first correlation signals and a Q signal component of the plurality of first correlation signals,

the rotating of the phases of the plurality of first correlation signals includes rotating phases of the I signal component of the plurality of first correlation signals and rotating phases of the Q signal component of the plurality of first correlation signals, and generating an I signal component of the added value by adding the I signal component of the phase-rotated plurality of first correlation signals and a Q component signal of the added value by adding the Q signal component of the phase-rotated plurality of first correlation signals, and

the determining of whether the phase-modulated input wave is the return wave from the determined object includes determining based on the I signal component of the added value and the Q signal component of the added value whether the phase-modulated input wave is the return wave from the determined object.

8. The detection method according to claim 7 , wherein:

the phase-modulated input wave is generated by phase-modulating a carrier wave using the determined code sequence, and

the determined frequency is a frequency of the carrier wave.

9. The detection method according to claim 7 , comprising:

rotating, by the detection device, phases of the first correlation signals by determined amounts based on a plurality of different amounts of a Doppler shift;

generating added values by adding the phase-rotated first correlation signals,

deriving a plurality of pieces of first strength information indicating strength of the phase-modulated input wave, based on the generated added values;

selecting one from the plurality of pieces of first strength information; and

determining whether the phase-modulated input wave is the return wave from the determined object.

10. The detection method according to claim 9 , wherein

the determined amounts based on the amounts of the Doppler shift are any one of 0°, 90°, 180°, or 270°.

11. The detection method according to claim 7 , further comprising:

detecting, by the detection device, an input wave from outside of the detection device, by a signal of a frequency different from that of a carrier wave;

generating, by the detection device, a second wave detection signal which detects the input wave;

computing, by the detection device, correlation of the second wave detection signal with the determined code sequence for every code composing the code sequence;

generating, by the detection device, a single second correlation signal; and

determining, by the detection device, based on the added value and the second correlation signal whether the determined object is present within a detection area of the detection device.

12. A non-transitory computer-readable recording medium storing a detection program that, when executed, causes a detection device to:

compute correlation of a first wave detection signal, which is a phase-modulated input wave detected at a determined frequency, with a determined code sequence for every code composing the code sequence, and generate a plurality of first correlation signals the number of which corresponds to a code sequence length, which is a length of the determined code sequence; and

rotate phases of the plurality of first correlation signals, generate an added value by adding the phase-rotated plurality of first correlation signals, and determine based on the added value whether the phase-modulated input wave is a return wave from a determined object, wherein:

the first wave detection signal includes an I signal component and a Q signal component, which are obtained by performing quadrature detection on the phase-modulated input wave,

the detection program causes the detection device to compute correlation of the first wave detection signal by causing the detection device to compute correlation of the I signal component of the first wave detection signal and the Q signal component of the first wave detection signal with the determined code sequence for every code composing the determined code sequence, and generate an I signal component of the plurality of first correlation signals and a Q signal component of the plurality of first correlation signals,

the detection program causes the detection device to rotate phases of the plurality of first correlation signals by causing the detection device to rotate phases of the I signal component of the plurality of first correlation signals and rotate phases of the Q signal component of the plurality of first correlation signals, and to generate an I signal component of the added value by adding the I signal component of the phase-rotated plurality of first correlation signals and a Q component signal of the added value by adding the Q signal component of the phase-rotated plurality of first correlation signals, and

the detection program causes the detection device to determine whether the phase-modulated input wave is the return wave from the determined object by causing the detection device to determine based on the I signal component of the added value and the Q signal component of the added value whether the phase-modulated input wave is the return wave from the determined object.

13. The computer-readable recording medium according to claim 12 , wherein:

the phase-modulated input wave is generated by phase-modulating a carrier wave using the determined code sequence, and

the determined frequency is a frequency of the carrier wave.

14. The computer-readable recording medium according to claim 12 , the detection program, when executed by the processor, causes the detection device to:

rotate phases of the first correlation signals by determined amounts based on a plurality of different amounts of a Doppler shift,

generate added values by adding the phase-rotated first correlation signals,

derive a plurality of pieces of first strength information indicating strength of the phase-modulated input wave, based on the generated added values,

select one from the plurality of pieces of first strength information, and

determine whether the phase-modulated input wave is the return wave from the determined object.

15. The computer-readable recording medium according to claim 14 , wherein

the determined amounts based on the amounts of the Doppler shift are any one of 0°, 90°, 180°, or 270°.

16. The computer-readable recording medium according to claim 12 , the detection program, when executed by the processor, causes the detection device to:

detect, by a signal of a frequency different from that of a carrier wave, an input wave from outside of the detection device and generate a second wave detection signal which detects the input wave; and

compute correlation of the second wave detection signal with the determined code sequence for every code composing the code sequence and generate a single second correlation signal; and

determine based on the added value and the second correlation signal whether the determined object is present within a detection area of the detection device.