Phase error compensation device and method of radar, and radar device including the same
The present embodiments relate to a phase error compensation device and method of a radar and a radar device including the same. A phase error compensation device according to an embodiment may include a first determiner configured to determine, for each first distance to a moving target, a first phase error between a phase of a first reception signal corresponding to a first transmission signal transmitted from a first transmission antenna and a phase of a second reception signal corresponding to a second transmission signal from a second transmission antenna, and a lookup table generator configured to generate and store a lookup table for phase compensation including phase compensation values for each distance based on the first phase error for each first distance.
1 . A phase error compensation device of a radar, including a first and a second transmission antennas and a plurality of reception antennas, comprising:
a first determiner configured to determine, for each first distance from among a plurality of first distances between the radar and a moving target, a first phase error between a phase of a first reception signal and a phase of a second reception signal,
wherein the plurality of first distances are defined as distances from the radar to the moving target as the moving target moves relative to the radar,
the first and second reception signals are received by the plurality of reception antennas, and
the first reception signal corresponds to a first transmission signal transmitted from the first transmission antenna and the second reception signal corresponds to a second transmission signal from the second transmission antenna; and
a lookup table generator configured to generate and store, based on the first phase error for the each first distance, a lookup table for compensating a phase of a target reception signal, the lookup table including phase compensation values corresponding to the each first distance.
2 . The phase error compensation device of claim 1 , further comprising a second determiner configured to determine, for each second distance from among a plurality of second distances between the radar and stationary reference targets, a second phase error between a phase of a first reference reception signal and a phase of a second reference reception signal,
wherein the plurality of second distances are defined as distances from the radar to the stationary reference targets as the stationary reference targets are located in different locations relative to the radar,
wherein the first reference reception signal corresponds to a first reference transmission signal transmitted from the first transmission antenna and the second reference reception signal corresponds to a second reference transmission signal transmitted from the second transmission antenna,
wherein the lookup table generator configured to generate the lookup table based on the second phase error for the each second distance.
3 . The phase error compensation device of claim 2 , wherein when, for the each first distance, a plurality of first reception signals and a plurality of second reception signals corresponding to the plurality of first distances are received, the first determiner is configured to exclude signals from among the plurality of first reception signals and signals from among the plurality of second reception signals whose phase linearity is smaller than a predetermined threshold, in determining the first phase error.
4 . The phase error compensation device of claim 3 , further comprising a storage unit for storing the first phase error for the each first distance and the second phase error for the each second distance.
5 . The phase error compensation device of claim 1 , wherein the first determiner is configured to determine the first phase error for the each first distance up to a far-field distance of the radar.
6 . The phase error compensation device of claim 5 , wherein the first determiner is configured to determine the first phase error for the each first distance up to the far-field distance of the radar of a multi-input multi-output (MIMO) type based on a single-input multi-output (SIMO) calibration distance for the first transmission antenna or the second transmission antenna.
7 . The phase error compensation device of claim 5 , wherein the first determiner is configured to
determine, for the each first distance, a plurality of first phase errors based on a plurality of first reception signals and a plurality of second reception signals corresponding to the plurality of first distances,
calculate an average value of the plurality of first phase errors, and
set the average value of the plurality of first phase errors as the first phase error for the each first distance.
8 . The phase error compensation device of claim 5 , wherein the first determiner is configured to performs a curve fitting in a range-phase error graph over the plurality of first distances, and determine the first phase error for the each first distance based on a fitting line.
9 . The phase error compensation device of claim 8 , wherein the fitting line in the range-phase error graph has a minimum absolute phase error value at a single-input multi-output (SIMO) based far-field distance (d far_SIMO ) for the first transmission antenna or the second transmission antenna.
10 . The phase error compensation device of claim 8 , wherein the fitting line in the range-phase error graph has a saturated phase error value at a distance greater than the far-field distance of the radar of a multi-input multi-output (MIMO) type.
11 . A phase error compensation method of a radar, including a first and a second transmission antennas and a plurality of reception antennas, comprising:
determining, for each first distance from among a plurality of first distances between the radar and a moving target, a first phase error between a phase of a first reception signal and a phase of a second reception signal,
wherein the plurality of first distances are defined as distances from the radar to the moving target as the moving target moves relative to the radar,
the first and second reception signals are received by the plurality of reception antennas, and
the first reception signal corresponds to a first transmission signal transmitted from the first transmission antenna and the second reception signal corresponding to a second transmission signal transmitted from the second transmission antenna; and
generating and storing, based on the first phase error for the each first distance, a lookup table for compensating a phase of a target reception signal, the lookup table including phase compensation values corresponding to the each first distance.
12 . The phase error compensation method of claim 11 , wherein
when, for the each first distance, a plurality of first reception signals and a plurality of second reception signals corresponding to the plurality of first distances are received, determining the first phase error comprises excluding signals from among the plurality of first reception signals and signals from among the plurality of second reception signals whose phase linearity is smaller than a predetermined threshold, in determining the first phase error.
13 . The phase error compensation method of claim 11 , wherein determining the first phase error comprises determining the first phase error for the each first distance up to a far-field distance of the radar of a multi-input multi-output (MIMO) type.
14 . The phase error compensation method of claim 13 , wherein determining the first phase error comprises determining the first phase error for the each first distance up to a far-field distance of the radar of the MIMO type based on a single-input multi-output (SIMO) calibration distance for the first transmission antenna or the second transmission antenna.
15 . The phase error compensation method of claim 13 , wherein determining the first phase error comprises performing a curve fitting in a range-phase error graph over the plurality of first distances, and determining the first phase error for the each first distance based on a fitting line.
16 . The phase error compensation method of claim 15 , wherein the fitting line in the range-phase error graph has a minimum absolute phase error value at a single-input multi-output (SIMO) based far-field distance (d far_SIMO ) for the first transmission antenna or the second transmission antenna.
17 . The phase error compensation method of claim 15 , wherein the fitting line in the range-phase error graph has a saturated phase error value at a distance greater than the far-field distance of the radar of the MIMO type.
18 . A radar device comprising:
an antenna unit including a transmission antenna unit with a first transmission antenna and a second transmission antenna, and a receiving antenna unit with a plurality of receiving antennas;
a transceiver configured to control to transmit a transmission signal through the transmission antenna unit and receive a reception signal through the receiving antenna unit;
a phase error compensation device configured to determine, for each first distance from among a plurality of first distances between the radar and a moving target, a first phase error between a phase of a first reception signal and a phase of a second reception signal,
wherein the plurality of first distances are defined as distances from the radar to the moving target as the moving target moves relative to the radar,
the first reception signal corresponds to a first transmission signal transmitted from the first transmission antenna and the second reception signal corresponds to a second transmission signal transmitted from the second transmission antenna, and
wherein the phase error compensation device is further configured to generate and store, based on the first phase error for the each first distance, a lookup table for compensating a phase of a target reception signal, the lookup table including phase compensation values corresponding to the each first distance; and
a signal processor configured to acquire target information by compensating the phase of the target reception signal based on the phase compensation values for the each first distance stored in the lookup table.
19 . The radar device of claim 18 , wherein when, for the each first distance, a plurality of first reception signals and a plurality of second reception signals corresponding to the plurality of first distances are received, the phase error compensation device is configured to exclude signals from among the plurality of first reception signals and signals from among the plurality of second reception signals whose phase linearity is smaller than a specific threshold, in determining the first phase error.
20 . The radar device of claim 19 , wherein the phase error compensation device is configured to determines the first phase error for the each first distance up to a far-field distance of the radar of a multi-input multi-output (MIMO) type.
21 . The radar device of claim 20 , wherein the phase error compensation device is configured to perform a curve fitting in a range-phase error graph over the plurality of first distances, and determine the first phase error for the each first distance based on a fitting line.
22 . The radar device of claim 18 , wherein the first transmission antenna and the second transmission antenna are arranged to be offset a predetermined distance in a vertical direction, and information on the moving target includes information on the vertical direction of the moving target.
23 . The radar device of claim 18 , wherein one receiving antenna from among the plurality of receiving antennas is arranged to be offset a predetermined distance in a vertical direction from remaining receiving antennas, and the information on the moving target includes information on the vertical direction of the moving target.