Method for correcting a radar signal to determine a synthetic aperture, computer program, device, and vehicle
Technologies and techniques for correcting a radar signal to determine a synthetic aperture. Data indicative of the radar signal is received, the radar signal having a sequence of echoes from a target region and being based on a sequence of transmission pulses. A movement of at least one target object in the target region is determined, and correction information for the radar signal is determined, based on the movement of the target object. An influence of the movement of the target object on the radar signal is reduced, based on the correction information to obtain a corrected radar signal.
1 . A method for correcting a radar signal to determine a synthetic aperture, comprising:
receiving data indicative of the radar signal, the radar signal having a sequence of echoes from a target region and being based on a sequence of transmission pulses;
determining movement of at least one target object in the target region during the sequence of transmission pulses;
determining correction information of the radar signal based on the determined movement of the target object, wherein the correction information corresponds to a movement-induced phase component of the radar signal associated with the movement of the target object; and
reducing a phase distortion in the radar signal caused by the movement of the target object by compensating the movement-induced phase component using the correction information to obtain a corrected radar signal.
2 . The method according to claim 1 , further comprising creating the synthetic aperture based on the corrected radar signal.
3 . The method according to claim 2 , wherein creating the synthetic aperture comprises constructing an image of the target region based on the corrected radar signal.
4 . The method according to claim 1 , wherein determining the movement of the at least one target object comprises determining a speed of the target object by a two-dimensional Fourier transformation of the radar signal.
5 . The method according to claim 4 , wherein determining the speed of the at least one target object comprises transforming the radar signal into a Doppler range.
6 . The method according to claim 1 , further comprising:
detecting a plurality of moving target objects in the target region;
determining a respective portion of correction information of the radar signal based on a movement of each of the detected target objects; and
reducing phase distortions in the radar signal caused by the movement of each of the detected target objects based on the respective correction information to obtain the corrected radar signal.
7 . The method according to claim 6 , wherein the influence of the movement of the target objects on the radar signal is iteratively reduced for each of the detected target objects.
8 . The method according to claim 6 , further comprising providing the respective correction information for parameterizing at least one respective filter for reducing the influence of the movement of each of the detected target objects on the radar signal.
9 . The method according to claim 1 , wherein the correction information is determined based on a movement-induced Doppler frequency shift in the radar signal.
10 . The method according to claim 1 , wherein the correction information is determined based on a movement-induced phase difference between at least two echoes in the sequence of echoes in the radar signal.
11 . The method according to claim 1 , wherein a first piece of correction information s 1 is determined according to
s
1
(
v
r
,
d
,
k
)
=
exp
(
-
2
π
jkT
RRI
2
λ
c
v
r
,
d
)
wherein k is an index of a transmission pulse in the sequence of transmission pulses, T RRI is a time difference between two consecutive transmission pulses in the sequence of transmission pulses, v r,d is a radial speed of the target object, and λ c is a wavelength of the transmission pulse in the sequence of transmission pulses, and the correction information is based on the first correction information s 1 .
12 . The method according to claim 11 , wherein a piece of second correction information s 2 is determined according to
s
2
(
v
r
,
d
,
t
)
=
exp
(
-
2
π
j
2
λ
c
v
r
,
d
t
)
wherein v r,d is a radial speed of the target object, λ c is a wavelength of a transmission pulse in the sequence of transmission pulses, and t is a measurement time of an echo in the sequence of echoes, and wherein the correction information is based on the second correction information s 2 .
13 . The method according to claim 12 , further comprising applying a compensation filter to the corrected radar signal during creation of the synthetic aperture, the compensation filter being configured to adjust a phase position of projected pixels of an image plane as a function of respective measurement positions of the transmission pulses.
14 . A device for correcting a radar signal for determining a synthetic aperture, comprising:
an interface circuit configured to receive data indicative of the radar signal, the radar signal including a sequence of echoes from a target region and being based on a sequence of transmission pulses; and
a processing circuit configured to:
determine a movement of at least one target object in the target region during the sequence of transmission pulses,
determine correction information of the radar signal based on the determined movement of the target object, wherein the correction information corresponds to a movement-induced phase component of the radar signal associated with the movement of the target object, and
reduce a phase distortion in the radar signal caused by the movement of the target object by compensating the movement-induced phase component using based on the correction information to obtain a corrected radar signal.
15 . The device according to claim 14 , further comprising creating the synthetic aperture based on the corrected radar signal.
16 . The device according to claim 15 , wherein creating the synthetic aperture comprises constructing an image of the target region based on the corrected radar signal.
17 . The device according to claim 14 , wherein determining the movement of the at least one target object comprises determining a speed of the target object by a two-dimensional Fourier transformation of the radar signal.
18 . The device according to claim 17 , wherein determining the speed of the at least one target object comprises transforming the radar signal into a Doppler range.
19 . The device according to claim 14 , further comprising:
detecting a plurality of moving target objects in the target region;
determining a respective portion of correction information of the radar signal based on a movement of each of the detected target objects; and
reducing an influence of the movement of each of the detected target objects on the radar signal based on the respective correction information to obtain the corrected radar signal.
20 . A non-transitory computer-readable medium including program instructions on a storage medium, configured to correct a radar signal to determine a synthetic aperture, comprising:
instructions for receiving data indicative of the radar signal, the radar signal having a sequence of echoes from a target region and being based on a sequence of transmission pulses;
instructions for determining movement of at least one target object in the target region during the sequence of transmission pulses;
instructions for determining correction information of the radar signal based on the determined movement of the target object, wherein the correction information corresponds to a movement-induced phase component of the radar signal associated with the movement of the target object; and
instructions for reducing a phase distortion in the radar signal caused by the movement of the target object by compensating the movement-induced phase component using based on the correction information to obtain a corrected radar signal.