Radar device, control circuit of radar device, and storage medium of radar device
A radar device includes a transmission module, a reception module, and a signal processing unit. The transmission module includes an RF signal source that generates a transmission chirp signal synchronized with a reference signal. The reception module includes an RF signal source that generates a reception chirp signal used as a reception local signal and synchronized with the reference signal. The reception module receives a reflected wave of the transmission chirp signal emitted from the transmission module, and mixes a received reception signal with the reception chirp signal. The signal processing unit detects a target based on a beat signal generated by the mixing by the reception module. The signal processing unit controls at least one of the RF signal sources such that between the transmission chirp signal and the reception chirp signal are output at timings shifted from each other, and corrects a change in a phase difference between the transmission module and the reception module, using a phase of a signal of a direct wave from the transmission module to the reception module.
1. A radar device comprising:
a transmitter including a first signal source to generate a transmission chirp signal synchronized with a reference signal;
a receiver including a second signal source to generate a reception chirp signal synchronized with the reference signal, the receiver receiving a reflected wave of the transmission chirp signal emitted from the transmitter, and mixing the received reception signal with the reception chirp signal; and
a signal processor to detect a target on a basis of a beat signal generated by the mixing by the receiver, wherein
the signal processor controls at least one of the first signal source or the second signal source to maintain constant a frequency difference between the transmission chirp signal and the reception chirp signal, and corrects a change in a phase difference between the transmitter and the receiver, using a phase of a signal of a direct wave from the transmitter to the receiver.
2. The radar device according to claim 1 , wherein
the signal processor controls the at least one of the first signal source and the second signal source such that the transmission chirp signal and the reception chirp signal are output at timings shifted from each other to produce the constant frequency difference.
3. The radar device according to claim 2 , wherein
a processing period for the signal processor is divided into a calibration period for correcting the change in the phase difference, and a normal measurement period for detecting the target, and
the signal processor corrects the change in the phase difference in the calibration period.
4. The radar device according to claim 2 , wherein
the signal processor detects the target also in a time period during which to correct the change in the phase difference.
5. The radar device according to claim 3 , wherein
the signal processor detects the target also in a time period during which to correct the change in the phase difference.
6. The radar device according to claim 1 , wherein
the receiver is a transceiver module including the first signal source to also operate as the transmitter, and
the radar device includes at least two of the transceivers.
7. The radar device according to claim 2 , wherein
the receiver is a transceiver module including the first signal source to also operate as the transmitter, and
the radar device includes at least two of the transceivers.
8. The radar device according to claim 6 , wherein
a processing period for the signal processor is divided into a first calibration period, a second calibration period, and a normal measurement period, wherein, during the first calibration period, the change in the phase difference is corrected on the basis of a reception signal received by a second transceiver module, the reception signal received by the second transceiver module being a transmission signal transmitted from a first transceiver module, wherein, during the second calibration period, the change in the phase difference is corrected on the basis of a reception signal received by the first transceiver module, the reception signal received by the first transceiver module being a transmission signal transmitted from the second transceiver module, and wherein the normal measurement period is provided for detection of the target, and
the signal processor corrects the change in the phase difference during the first and second calibration periods.
9. The radar device according to claim 7 , wherein
a processing period for the signal processor is divided into a first calibration period, a second calibration period, and a normal measurement period, wherein, during the first calibration period, the change in the phase difference is corrected on the basis of a reception signal received by a second transceiver module, the reception signal received by the second transceiver module being a transmission signal transmitted from a first transceiver module, wherein, during the second calibration period, the change in the phase difference is corrected on the basis of a reception signal received by the first transceiver module, the reception signal received by the first transceiver module being a transmission signal transmitted from the second transceiver module, and wherein the normal measurement period is provided for detection of the target, and
the signal processor corrects the change in the phase difference during the first and second calibration periods.
10. The radar device according to claim 6 , wherein
a processing period for the signal processor is divided into a calibration period during which the change in the phase difference is corrected on the basis of transmission-reception signals transmitted and received between a first transceiver module and a second transceiver module, and a normal measurement period for detection of the target, and
the signal processor corrects the change in the phase difference during the calibration period.
11. The radar device according to claim 7 , wherein
a processing period for the signal processor is divided into a calibration period during which the change in the phase difference is corrected on the basis of transmission-reception signals transmitted and received between a first transceiver module and a second transceiver module, and a normal measurement period for detection of the target, and
the signal processor corrects the change in the phase difference during the calibration period.
12. The radar device according to claim 6 , wherein
the signal processor detects the target also in a time period during which to correct the change in the phase difference.
13. The radar device according to claim 7 , wherein
the signal processor detects the target also in a time period during which to correct the change in the phase difference.
14. The radar device according to claim 8 , wherein
the signal processor detects the target also in a time period during which to correct the change in the phase difference.
15. The radar device according to claim 9 , wherein
the signal processor detects the target also in a time period during which to correct the change in the phase difference.
16. The radar device according to claim 10 , wherein
the signal processor detects the target also in a time period during which to correct the change in the phase difference.
17. The radar device according to claim 11 , wherein
the signal processor detects the target also in a time period during which to correct the change in the phase difference.
18. A control circuit of a radar device, the radar device comprising: a transmitter including a first signal source to generate a transmission chirp signal synchronized with a reference signal; and a receiver including a second signal source to generate a reception chirp signal synchronized with the reference signal, the receiver receiving a reflected wave of the transmission chirp signal emitted from the transmitter, and mixing the received reception signal with the reception chirp signal, wherein
the control circuit detects a target on a basis of a beat signal generated by the mixing by the receiver, wherein
the control circuit controls at least one of the first signal source or the second signal source to maintain constant a frequency difference between the transmission chirp signal and the reception chirp signal, and corrects a change in a phase difference between the transmitter and the receiver, using a phase of a signal of a direct wave from the transmitter to the receiver.
19. A non-transitory storage medium of a radar device, the radar device comprising: a transmitter including a first signal source to generate a transmission chirp signal synchronized with a reference signal; and a receiver including a second signal source to generate a reception chirp signal synchronized with the reference signal, the receiver receiving a reflected wave of the transmission chirp signal emitted from the transmitter, and mixing the received reception signal with the reception chirp signal, wherein
the medium stores a program which, when executed by a processor, performs:
detecting a target on a basis of a beat signal generated by the mixing by the receiver; and
controlling at least one of the first signal source or the second signal source to maintain constant a frequency difference between the transmission chirp signal and the reception chirp signal, and correcting a change in a phase difference between the transmitter and the receiver, using a phase of a signal of a direct wave from the transmitter to the receiver.