Virtual beam steering using MIMO radar
Examples disclosed herein relate to a Multiple-Input Multiple-Output (MIMO) radar for virtual beam steering. The MIMO radar has a plurality of transmit antennas and a receive antenna array having a plurality of radiating elements. The MIMO radar also includes a digital signal processor (DSP) configured to synthesize a virtual receive array having N×M receive subarrays from the plurality of transmit antennas and the receive antenna array, where N is the number of transmit antennas and M is the number of receiving elements. Other examples disclosed herein relate to a method of virtual beam steering.
1. A method of processing data for an antenna system, comprising:
synthesizing a virtual receive array representing a plurality of transmit antennas and a plurality of receive antenna elements of the antenna system;
determining a manifold matrix that represents the virtual receive array based on a function of a geometry of the virtual receive array, a carrier frequency, and a direction of arrival of signal data received from the plurality of transmit antennas;
generating a transformation matrix from the virtual receive array and the manifold matrix; and
determining a linear transformation matrix using an optimization criterion that is a function of the virtual receive array and the transformation matrix,
wherein the antenna system is configured to operate in a Multiple-Input Multiple-Output (MIMO) radar system.
2. The method of claim 1 , further comprising:
generating a data set representing beam steering properties using the determined linear transformation matrix and the received signal data.
3. The method of claim 1 , wherein the virtual receive array is represented as:
A
=
[
g
1
1
e
-
j
w
0
τ
1
1
…
g
1
N
e
-
j
w
0
τ
1
N
⋮
⋱
⋮
g
M
1
e
-
j
w
0
τ
M
1
…
g
M
N
e
-
j
w
0
τ
M
N
]
where g ij is channel response between i th transmit antenna to j th receive antenna element, w o is a center frequency, and τ ij is time delay between the i th transmit antenna to the j th receive antenna element, for i=1, 2, . . . , M and j=1, 2, . . . , N.
4. The method of claim 3 , wherein the time delay τ ij is defined as:
τ
i
j
=
1
c
d
i
j
sin
(
θ
i
)
where d ij is a distance between the i th transmit antenna to a reference element, Θ i , which is an incident angle between a direction of an incident signal received at the i th transmit antenna and a normal perpendicular to a plane of the virtual receive array.
5. The method of claim 4 , further comprising:
digitally processing the incident signal as a radar return signal.
6. The method of claim 1 , further comprising:
applying the linear transformation matrix to a first transmit antenna of the plurality of transmit antennas; and
determining a second transmit antenna positioned at an angle relative to an original position of the first transmit antenna.
7. The method of claim 1 , further comprising:
applying the linear transformation matrix to a first receive antenna element of the plurality of receive antenna elements; and
determining a second receive antenna at an angle relative to an original position of the first receive element.
8. A radar system, comprising:
an array of antenna elements comprising a plurality of transmit antenna elements and a plurality of receive antenna elements; and
a digital signal processing unit configured to apply virtual antenna beam steering to the radar system, the virtual antenna beam steering comprising a virtual receive antenna array representing the array of antenna elements and a transformation matrix configured to perform linear transformations on the virtual receive antenna array,
wherein the array of antenna elements comprises a first transmit subarray and a second transmit subarray, the first transmit subarray associated with a first steering angle of the radar system.
9. The radar system of claim 8 , wherein the radar system is a Multiple-Input Multiple-Output (MIMO) radar system.
10. The radar system of claim 8 , wherein the virtual receive antenna array is represented by a manifold matrix that is a function of a geometry of the array of antenna elements and a carrier frequency.
11. The radar system of claim 8 , further comprising:
a MIMO radar configuration configured to apply linear transformation to the plurality of transmit antenna elements to determine a second steering angle for the second transmit subarray.
12. The radar system of claim 11 , wherein the plurality of receive antenna elements comprises a first receive subarray and a second receive subarray, and wherein the MIMO radar configuration is further configured to apply linear transformation to the plurality of receive antenna elements to determine a second receive angle for the second receive subarray.
13. The radar system of claim 8 , further comprising:
a memory storage device that stores a data set representing beam steering properties for linear transformations in the radar system.
14. A method of operating a beam steering radar, comprising:
determining a manifold matrix from an antenna array of the beam steering radar, the antenna array comprising a plurality of transmit antennas and a plurality of receive antennas;
applying a plurality of steering angle properties to the manifold matrix;
generating a transformation matrix based on the applied steering angle properties to the manifold matrix;
applying a linear transformation to the manifold matrix using the generated transformation matrix; and
producing a data set representing beam steering properties of the beam steering radar based on the applied linear transformation.
15. The method of claim 14 , further comprising:
storing the generated data set representing the beam steering properties of the beam steering radar in a memory storage unit coupled to the beam steering radar.
16. The method of claim 14 , further comprising:
applying a linear transformation matrix with interpolation to the manifold matrix to generate an oriented virtual subarray.
17. The method of claim 14 , wherein the beam steering radar is a Multiple-Input Multiple-Output (MIMO) radar system.
18. The method of claim 14 , wherein the manifold matrix represents a virtual receive array based on a function of a carrier frequency and direction of arrival of signals received at least at a portion of the plurality of transmit antennas.
19. A radar system, comprising:
an array of antenna elements comprising a plurality of transmit antenna elements and a plurality of receive antenna elements;
a digital signal processing unit configured to apply virtual antenna beam steering to the radar system, the virtual antenna beam steering comprising a virtual receive antenna array representing the array of antenna elements and a transformation matrix configured to perform linear transformations on the virtual receive antenna array; and
a memory storage device that stores a data set representing beam steering properties for linear transformations in the radar system.
20. The radar system of claim 19 , wherein the radar system is a Multiple-Input Multiple-Output (MIMO) radar system.