US 12,276,720 B2
Radar device, observation target detecting method, and in-vehicle device
Yusuke Kitsukawa, Tokyo (JP); and Noriyuki Fukui, Tokyo (JP)
Assigned to MITSUBISHI ELECTRIC CORPORATION, Tokyo (JP)
Filed by MITSUBISHI ELECTRIC CORPORATION, Tokyo (JP)
Filed on Jun. 15, 2022, as Appl. No. 17/840,992.
Application 17/840,992 is a continuation of application No. PCT/JP2020/006957, filed on Feb. 21, 2020.
Prior Publication US 2022/0308197 A1, Sep. 29, 2022
Int. Cl. G01S 13/58 (2006.01); G01S 7/35 (2006.01); G01S 13/34 (2006.01); G01S 13/87 (2006.01)
CPC G01S 13/584 (2013.01) [G01S 13/34 (2013.01); G01S 13/87 (2013.01); G01S 7/356 (2021.05)] 13 Claims
OG exemplary drawing
 
1. A radar device comprising:
a plurality of radars each to transmit, as a radar signal, a frequency modulated signal whose frequency linearly changes with a lapse of time, and receive a reflected wave of the radar signal reflected by an observation target; and
processing circuitry configured to:
calculate distance and velocity information indicating a distance to the observation target and a relative velocity with respect to the observation target, by using digital data of a beat signal having a frequency of a difference between a frequency of the radar signal and a frequency of the reflected wave, and
detect the observation target on a basis of the distance and velocity information, wherein:
the radars are configured to transmit, as radar signals, frequency modulated signals whose frequency gradients with a lapse of time are different from each other, each ratio of absolute values of the frequency gradients being other than 1, and
the processing circuitry is configured to calculate a first frequency spectrum obtained by performing Fourier transform in a distance direction on the digital data of the beat signal and a second frequency spectrum obtained by performing Fourier transform in a relative velocity direction on the first frequency spectrum, and calculate, for each of the radars, the distance and velocity information on a basis of a beat frequency and a Doppler frequency corresponding to a peak value in the second frequency spectrum, and
the processing circuitry is configured to compare the distance and velocity information calculated for each of the radars,
the processing circuitry is configured to, when the distance and velocity included in the distance and velocity information match between the radars, determine that the distance and velocity included in the distance and velocity information are the distance to the observation target and the relative velocity with respect to the observation target, and
the processing circuitry is configured to, when the distance and velocity included in the distance and velocity information do not match between the radars due to their differences corresponding to differences in frequency gradients of radar signals, determine that the distance and velocity included in the distance and velocity information result from erroneous detection due to electromagnetic noise.