Method for processing radar sensing data, radar device, and vehicle including radar device

1 . A method for processing radar sensing data by a time division multiplexing (TDM) frequency modulation continuous wave (FMCW) radar device, the method comprising:

generating a first array by using signals emitted and received by the TDM FMCW radar device, the first array being a four-dimensional array having a sampling index, a chirp index, a virtual channel, and a transmission channel, as dimensions, respectively, wherein the TDM FMCW radar device has N×M virtual channels implemented by N transmission channels (N is a natural number more than 1) and M reception channels (M is a natural number more than 1), and locations of at least some channels of the N×M virtual channels overlap each other;

generating a second array by performing, in a sampling index dimension direction, range fast Fourier transform (FFT) on each virtual channel of each of the N transmission channels of the first array, the second array being a four-dimensional array having a range index, a chirp index, a virtual channel, and a transmission channel as dimensions, respectively;

generating a third array by adding, in a chirp index dimension direction, predetermined data to the second array based on the N transmission channels;

generating a fourth array by performing, in the chirp index dimension direction, the FFT on each virtual channel of each of the N transmission channels of the third array, the fourth array being a four-dimensional array having a range index, a Doppler index, a virtual channel, and a transmission channel as dimensions, respectively;

generating a range-Doppler map from the fourth array;

extracting, from the range-Doppler map, L peaks (L is a natural number) having a range index and a Doppler index satisfying a predetermined condition;

extracting, from among the L peaks, at least one peak having a phase difference of two adjacent virtual channels, which is less than a predetermined threshold difference; and

determining at least one physical quantity related to movement of an object by using the extracted peak.

2 . The method of claim 1 , wherein the generating of the third array includes:

generating, from the second array, N first partial arrays which are arrays for each of the N transmission channels;

dividing each of the N first partial arrays into K two-dimensional layers (K is a natural number) defined by axes of a dimension of a range index of each of the N first partial arrays and a dimension of a virtual channel of each of the N first partial arrays based on a chirp index of each of the N first partial arrays;

adding, in a chirp index direction, at least one zero-padding layer to each of the K two-dimensional layers of each of the N first partial arrays, the zero-padding layer being a layer defined by the axes of the dimension of the range index of each of the N first partial arrays and the dimension of the virtual channel of each of the N first partial arrays and including only zero; and

generating the third array by generating N zero-padded partial arrays for each of the N first partial arrays by merging the K two-dimensional layers and the added at least one zero-padding layer, and merging the generated N zero-padded partial arrays.

3 . The method of claim 2 , wherein the adding of the at least one zero-padding layer to each of the K two-dimensional layers of each of the N first partial arrays includes:

identifying a sequence number J (J is a natural number) which is a sequence number of a transmission channel of a first partial array to which the zero-padding layer is to be added;

adding, in the chirp index direction, J-1 preceding zero-padding layers to each of the K two-dimensional layers; and

adding, in the chirp index direction, J-2 following zero-padding layers to each of the K two-dimensional layers.

4 . The method of claim 1 , wherein the generating of the third array includes:

generating, from the second array, N×N×M second partial arrays which are arrays for each of the N×M virtual channels for each of the N transmission channels;

generating C columns from each of the second partial arrays, each of the C columns being obtained by dividing each of the second partial arrays based on the chirp index of the second array;

adding at least one zero-padding column to each of the C columns, the zero-padding column being a column including only zero; and

generating the third array by generating zero-padded partial arrays for each of the second partial arrays by merging the C columns and the added at least one zero-padding column, and merging the generated zero-padded partial arrays.

5 . The method of claim 4 , wherein the adding of the at least one zero-padding column to each of the C columns includes:

identifying a sequence number P (P is a natural number) which is a sequence number of a transmission channel of a second partial array to which the zero-padding column is to be added;

adding, in a chirp index direction, P-1 preceding zero-padding columns to each of the C columns; and

adding, in the chirp index direction, P-2 following zero-padding columns to each of the C columns.

6 . The method of claim 1 , wherein the generating of the range-Doppler map includes:

generating, from the fourth array, first range-Doppler maps for each of the virtual channels by merging Doppler FFT results for each of the N transmission channels based on each of the virtual channels; and

generating a second range-Doppler map by merging the first range-Doppler maps for each of the virtual channels,

wherein the extracting of the L peaks from the range-Doppler map includes extracting the L peaks from the second range-Doppler map.

7 . The method of claim 6 , wherein the generating of the range-Doppler map further includes generating a third range-Doppler map based on at least one of the first range-Doppler maps for each of the virtual channels,

wherein the extracting of the L peaks from the range-Doppler map includes extracting the L peaks from the third range-Doppler map.

8 . The method of claim 1 , wherein the predetermined condition for extracting the L peaks includes a condition in which Doppler indexes between the L peaks have intervals corresponding to a predetermined interval, and range index values of the L peaks are within a threshold difference from one of the range index values of the L peaks.

9 . The method of claim 1 , wherein the extracting of the at least one peak from among the L peaks includes:

identifying phases of each of the L peaks on each of the virtual channels;

calculating, for each of the L peaks, phase differences between two adjacent virtual channels of the virtual channels; and

extracting, from among the L peaks, a peak having a lowest value from among the calculated phase differences.

10 . A time division multiplexing (TDM) frequency modulation continuous wave (FMCW) radar device comprising:

an antenna unit including N transmission antennas (N is a natural number greater than or equal to 2), M reception antennas (M is a natural number greater than or equal to 2), and N×M virtual antennas implemented according to an array of the N transmission antennas and the M reception antennas, wherein locations of at least some channels of the N×M virtual antennas overlap each other;

a radar integrated circuit (IC) configured to process signals transmitted and received by the antenna unit; and

a processor configured to determine at least one physical quantity related to movement of an object by analyzing the received signals,

wherein the processor is configured to: generate a first array by using the signals transmitted and received via the antenna unit, the first array being a four-dimensional array having a sampling index, a chirp index, a virtual channel, and a transmission channel as dimensions, respectively; generate a second array by performing, in a sampling index dimension direction, range fast Fourier transform (FFT) on each virtual channel of each of the N transmission channels of the first array, the second array being a four-dimensional array having a range index, a chirp index, a virtual channel, and a transmission channel as dimensions, respectively; generate a third array by adding, in a chirp index dimension direction, predetermined data to the second array based on the N transmission channels; generate a fourth array by performing, in the chirp index dimension direction, FFT on each virtual channel of each of the N transmission channels of the third array, the fourth array being a four-dimensional array having a range index, a Doppler index, a virtual channel, and a transmission channel as dimensions, respectively; generate a range-Doppler map from the fourth array; extract, from the range-Doppler map, L peaks (L is a natural number) having a range index and a Doppler index satisfying a predetermined condition; extract, from among the L peaks, at least one peak having a phase difference of two adjacent virtual channels, which is less than a predetermined threshold difference; and determine at least one physical quantity related to the movement of the object by using the extracted peak.

11 . The TDM FMCW radar device of claim 10 , wherein the processor is configured to: generate, from the second array, N first partial arrays which are arrays for each of the N transmission channels; divide each of the N first partial arrays into K two-dimensional layers (K is a natural number) defined by axes of a dimension of a range index of each of the N first partial arrays and a dimension of a virtual channel of each of the N first partial arrays based on a chirp index of each of the N first partial arrays; add, in a chirp index direction, at least one zero-padding layer to each of the K two-dimensional layers of each of the N first partial arrays, the zero-padding layer being a layer defined by the axes of the dimension of the range index of each of the N first partial arrays and the dimension of the virtual channel of each of the N first partial arrays and including only zero; and generate the third array by generating N zero-padded partial arrays for each of the N first partial arrays by merging the K two-dimensional layers and the added at least one zero-padding layer, and merging the generated N zero-padded partial arrays.

12 . The TDM FMCW radar device of claim 11 , wherein the processor is configured to: identify a sequence number J (J is a natural number) which is a sequence number of a transmission channel of a first partial array to which the zero-padding layer is to be added; add, in the chirp index direction, J-1 preceding zero-padding layers to each of the K two-dimensional layers; and add, in the chirp index direction, J-2 following zero-padding layers to each of the K two-dimensional layers.

13 . The TDM FMCW radar device of claim 10 , wherein the processor is configured to: generate, from the second array, N×N×M second partial arrays which are arrays of each of the N×M virtual channels for each of the N transmission channels; generate C columns from each of the second partial arrays, each of the C columns being obtained by dividing each of the second partial arrays based on the chirp index of the second array; add at least one zero-padding column to each of the C columns, the zero-padding column being a column including only zero; and generate the third array by generating zero-padded partial arrays for each of the second partial arrays by merging the C columns and the added at least one zero-padding column, and merging the generated zero-padded partial arrays.

14 . The TDM FMCW radar device of claim 13 , wherein the processor is configured to: identify a sequence number P (P is a natural number) which is a sequence number of a transmission channel of a second partial array to which the zero-padding column is to be added; add, in a chirp index direction, P-1 preceding zero-padding columns to each of the C columns; and add, in the chirp index direction, P-2 following zero-padding columns to each of the C columns.

15 . The TDM FMCW radar device of claim 10 , wherein the processor is configured to: generate, from the fourth array, first range-Doppler maps for each of the virtual channels by merging Doppler FFT results for each of the N transmission channels based on each of the virtual channels; generate a second range-Doppler map by merging the first range-Doppler maps for each of the virtual channels; and extract the L peaks from the second range-Doppler map.

16 . The TDM FMCW radar device of claim 15 , wherein the processor is configured to: generate a third range-Doppler map based on at least one of the first range-Doppler maps for each the virtual channels; and extract the L peaks from the third range-Doppler map.

17 . The TDM FMCW radar device of claim 10 , wherein the predetermined condition for extracting the L peaks includes a condition in which Doppler indexes between the L peaks have intervals corresponding to a predetermined interval, and range index values of the L peaks are within a threshold difference from one of the range index values of the L peaks.

18 . The TDM FMCW radar device of claim 10 , wherein the processor is configured to: identify phases of each of the L peaks on each of the virtual channels; calculate, for each of the L peaks, phase differences between two adjacent virtual channels of the virtual channel; and extract, from among the L peaks, a peak having a lowest value from among the calculated phase differences.

19 . A vehicle comprising:

a vehicle body including a controller configured to control a vehicle; and

a radar device configured to provide information of sensing a surrounding object via the controller, wherein the radar device includes: an antenna unit including N transmission antennas (N is a natural number greater than or equal to 2), M reception antennas (M is a natural number greater than or equal to 2), and N×M virtual antennas implemented according to an array of the N transmission antennas and the M reception antennas, wherein locations of at least some channels of the N×M virtual antennas overlap each other; a radar integrated circuit (IC) configured to process signals transmitted and received by the antenna unit; and a processor configured to determine at least one physical quantity related to movement of the object by analyzing the received signals, wherein the processor is configured to: generate a first array by using the signal transmitted and received via the antenna unit, the first array being a four-dimensional array having a sampling index, a chirp index, a virtual channel, and a transmission channel, as dimensions, respectively; generate a second array by performing, in a sampling index dimension direction, range fast Fourier transform (FFT) on each virtual channel of each of the N transmission channels of the first array, the second array being a four-dimensional array having a range index, a chirp index, a virtual channel, and a transmission channel as dimensions, respectively; generate a third array by adding, in a chirp index dimension direction, predetermined data to the second array based on the N transmission channels; generate a fourth array by performing, in a chirp index dimension direction, FFT on each virtual channel of each of the N transmission channels of the third array, the fourth array being a four-dimensional array having a range index, a Doppler index, a virtual channel, and a transmission channel as dimension, respectively; generate a range-Doppler map from the fourth array; extract, from the range-Doppler map, L peaks (L is a natural number) having a range index and a Doppler index satisfying a predetermined condition; extract, from among the L peaks, at least one peak having a phase difference of two adjacent virtual channels, which is less than a predetermined threshold difference; and determine at least one physical quantity related to movement of the object by using the extracted peak.