Patent ID: 11921186
Assignee: MITSUBISHI ELECTRIC CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 30:
31. A method for operating a radar device that includes: at least one transmitter to generate a transmission chirp signal synchronized with a timing signal; at least two receivers to each receive a reflected wave and a direct wave of the transmission chirp signal emitted from the transmitter, each generates a reception chirp signal, and each performs mixing on a received signal, using a reception chirp signal, the reception chirp signal being synchronized with the timing signal and having the same slope as the transmission chirp signal; and a signal processor to analyze a beat signal resulting from the mixing performed by the receivers, the signal processor detecting a target from a reflected wave component of the beat signal resulting from the mixing performed by the receivers, detecting a level of a direct wave component of the beat signal, and determining a failure of the device by comparing the detected level with a threshold, the threshold being set on the basis of a beat signal level measurement under an environment that eliminates the reflected wave component in advance, wherein
the transmission chirp signal and the reception chirp signal
include a first chirp signal for target detection and a second chirp signal for failure detection; and
have a first radar operation cycle in which the first chirp signal is transmitted and received so that the target is detected on the basis of a beat signal from the first chirp signal, and a second radar operation cycle in which the second chirp signal is transmitted and received so that a failure of the radar device is determined on the basis of a beat signal from the second chirp signal, and
the second radar operation cycle is controlled on the basis of a timing signal output from the signal processor, and is included at least once within a plurality of cycles of the first radar operation, and wherein
the threshold is set for each ambient temperature of the radar device,
the threshold is saved, in a memory of the signal processor, as a temperature table value set for a direct wave of a plurality of transmission/reception paths formed by at least the one transmitter and at least the two receivers, and
the signal processor performs failure determination on the radar device by setting the threshold corresponding to each of a plurality of the transmission/reception paths by interpolating or referring to a corresponding one of the temperature table value on the basis of the level of the direct wave component in each beat signal.