Radar device and gain adjustment method
A radar apparatus is provided with: a transmitter for transmitting a transmission signal in which the frequency is changed over time; a receiver for receiving a radio wave returned by the transmission signal being reflected by an object as a reception signal; a frequency convertor for generating an in-phase signal and a quadrature signal based on the reception signal; an amplitude signal generator for generating an in-phase amplitude signal indicating the amplitude of the in-phase signal and a quadrature amplitude signal indicating the amplitude of the quadrature signal; a maximum value selector for selecting the higher level of the in-phase amplitude signal and the quadrature amplitude signal as the maximum value signal; and a gain adjuster for adjusting the gain of the reception signal based on the maximum value signal.
1 . A radar apparatus comprising:
a transmitter configured to transmit a transmission signal having a frequency configured to change over time;
a receiver configured to receive a radio wave reflected by an object as a reception signal; and
processing circuitry configured to:
generate, based on the reception signal, each of an in-phase amplitude signal and a quadrature amplitude signal,
wherein the in-phase amplitude signal and the quadrature amplitude signal are offset in time; and
generate a maximum value signal based on the in-phase amplitude signal and the quadrature amplitude signal
wherein, during a duration of time, the maximum value signal comprises maximum values of each of the in-phase amplitude signal and the quadrature amplitude signal,
wherein, at any moment in time during the duration, the maximum value signal comprises either:
only one of the in-phase amplitude signal or the quadrature amplitude signal that has a largest maximum value, or
either the in-phase amplitude signal or the quadrature amplitude signal when the respective maximum values are equal; and
to adjust the gain of the received signal based on the maximum value signal.
2 . The radar apparatus according to claim 1 , further comprising:
a low-pass filter configured to receive the maximum value signal and to output an attenuated maximum value signal, the attenuated maximum value signal having a constant frequency that is equal to or greater than a predetermined cut-off frequency of the low-pass filter,
wherein the processing circuitry is further configured:
to adjust the gain of the received signal based on the attenuated component of the maximum value signal that is output from the low-pass filter.
3 . The radar apparatus according to claim 2 , wherein:
a portion of the processing circuitry comprises an analog circuit.
4 . The radar apparatus according to claim 1 , wherein the in-phase amplitude signal and the quadrature amplitude signal correspond to a baseband band.
5 . The radar apparatus according to claim 1 wherein the processing circuitry is further configured:
to digitally convert the in-phase signal and the quadrature signal; and
to convert the in-phase signal and the quadrature signal digitally converted by the A/D convertor into amplitude data indicating a relationship between distance and amplitude.
6 . A gain adjustment method in a radar apparatus comprising:
transmitting a transmission signal having a frequency configured to change over time;
receiving a radio wave reflected by an object as a reception signal;
generating in-phase and quadrature signals based on the reception signal;
generating, based on the reception signal, each of an in-phase amplitude signal and a quadrature amplitude signal,
wherein the in-phase amplitude signal and the quadrature amplitude signal are offset in time; and
generating a maximum value signal based on the in-phase amplitude signal and the quadrature amplitude signal,
wherein, during a duration of time, the maximum value signal comprises maximum values of each of the in-phase amplitude signal and the quadrature amplitude signal,
wherein, at any moment in time during the duration, the maximum value signal comprises either:
only one of the in-phase amplitude signal or the quadrature amplitude signal that has a largest maximum value, or
either the in-phase amplitude signal or the quadrature amplitude signal when the respective maximum values are equal; and
adjusting the gain of the received signal based on the maximum value signal.
7 . The gain adjustment method according to claim 6 , further comprising:
performing a low-pass filtering process on the maximum value signal to generate an attenuated maximum value signal, the attenuated maximum value signal having a constant frequency that is equal to or greater than a predetermined cut-off frequency of the low-pass filter,
wherein the adjusting the gain comprises adjusting the gain of the received signal based on the attenuated component of the maximum value signal.
8 . A non-transitory computer readable medium having stored thereon computer-executable instructions which, when executed by a computer, cause the computer to:
transmit a transmission signal having a frequency configured to change over time;
receive a radio wave reflected by an object as a reception signal;
generate, based on the reception signal, each of an in-phase amplitude signal and a quadrature amplitude signal,
wherein the in-phase amplitude signal and the quadrature amplitude signal are offset in time; and
generate a maximum value signal based on the in-phase amplitude signal and the quadrature amplitude signal,
wherein, during a duration of time, the maximum value signal comprises maximum values of each of the in-phase amplitude signal and the quadrature amplitude signal,
wherein, at any moment in time during the duration, the maximum value signal comprises either:
only one of the in-phase amplitude signal or the quadrature amplitude signal that has a largest maximum value, or
either the in-phase amplitude signal or the quadrature amplitude signal when the respective maximum values are equal; and
adjust the gain of the received signal based on the maximum value signal.
9 . The radar apparatus according to claim 2 , wherein the in-phase amplitude signal and the quadrature amplitude signal correspond to a baseband band.
10 . The radar apparatus according to claim 3 , wherein the in-phase amplitude signal and the quadrature amplitude signal correspond to a baseband band.
11 . The radar apparatus according to claim 2 wherein
the processing circuitry is further configured:
to digitally convert the in-phase signal and the quadrature signal; and
to convert the in-phase signal and the quadrature signal digitally converted by the A/D convertor into amplitude data indicating a relationship between distance and amplitude.
12 . The radar apparatus according to claim 3 wherein
the processing circuitry is further configured:
to digitally convert the in-phase signal and the quadrature signal; and
to convert the in-phase signal and the quadrature signal digitally converted by the A/D convertor into amplitude data indicating a relationship between distance and amplitude.
13 . The radar apparatus according to claim 4 wherein
the processing circuitry is further configured:
to digitally convert the in-phase signal and the quadrature signal; and
to convert the in-phase signal and the quadrature signal digitally converted by the A/D convertor into amplitude data indicating a relationship between distance and amplitude.