Imaging radar sensor with narrow antenna lobe and wide angle-detection range
The invention relates to a device for detecting objects within a sweep range, comprising at least two switchable transmitting antennas ( 10 ), a plurality of receiving antennas ( 20 ), the transmitting antennas ( 10 ) and receiving antennas ( 20 ) respectively extending longitudinally, parallel to one another, in a first direction (y), and the receiving antennas ( 10 ) being arranged in a row and the row extending in a second direction (x), the receiving antennas ( 20 ) and the transmitting antennas ( 10 ) being arranged such that they produce a synthetic receiving antenna array for the beam sweep by means of the sequential activation of the transmitting antennas and the positions of the transmitting and receiving antennas, the resulting distance corresponding to the positions of the receiving antennas in the synthetic receiving antenna array in the second direction d, the adjacent receiving antennas in the device being spaced apart by a distance of d 2 or greater and d 2 being twice as great as distance d.
1. A method comprising:
transmitting signals by sequentially operating two transmitting antennas offset from one another along a first direction by a first distance;
receiving reflected signals using a receiving antenna array, wherein the receiving antenna array comprises a plurality of receiving antennas arranged in a row extending in the first direction, and wherein adjacent antennas are offset from one another along the first direction by a second distance, the second distance being twice as great as the first distance;
digitizing the received signals;
processing the received signals according to a synthetic array, wherein the synthetic array comprises a plurality of lines arranged in a row extending in the first direction, each line corresponding to a respective one of the transmitting antennas and a respective one of the receiving antennas; and
reducing a secondary lobe of the synthetic array, wherein reducing the secondary lobe of the synthetic array comprises weighting one or more lines of the synthetic array according to a Dolph-Chebyshev function.
2. The method of claim 1 , further comprising performing a beam sweep by an angle θ with respect to the synthetic array.
3. The method of claim 2 , wherein performing the beam sweep by the angle θ with respect to the synthetic array comprises phase shifting one or more lines of the synthetic array.
4. The method of claim 3 , wherein each of the lines of the synthetic array are phase shifted by a multiple of an angle α.
5. The method of claim 4 , wherein the angle α is determined based on a wavelength of the received signals and a distance between adjacent lines of the synthetic array.
6. The method of claim 4 , wherein the angle α is determined as:
α
=
-
2
π
d
λ
sin
θ
,
wherein λ is a wavelength of the received signals, and d is a distance between adjacent lines of the synthetic array.
7. The method of claim 4 , wherein a first line at an end of the synthetic array is phase shifted by N multiplied by α, and wherein a second line at an opposite end of the synthetic array is phase shifted by −N multiplied by α.
8. A system comprising:
two transmitting antennas offset from one another along a first direction by a first distance, wherein the two transmitting antennas are configured to be sequentially operated to transmit signals;
a receiving antenna array comprising a plurality of receiving antennas arranged in a row extending in the first direction, wherein adjacent antennas are offset from one another along the first direction by a second distance, the second distance being twice as great as the first distance, and wherein the receiving antenna array is configured to receive reflected signals; and
a signal processor configured to:
digitize the received signals;
process the received signals according to a synthetic array, wherein the synthetic array comprises a plurality of lines arranged in a row extending in the first direction, each line corresponding to a respective one of the transmitting antennas and a respective one of the receiving antennas; and
reduce a secondary lobe of the synthetic array.
9. The system of claim 8 , wherein the signal processor is further configured to perform a beam sweep by an angle θ with respect to the synthetic array.
10. The system of claim 9 , wherein performing the beam sweep by the angle θ with respect to the synthetic array comprises phase shifting one or more lines of the synthetic array.
11. The system of claim 10 , wherein each of the lines of the synthetic array are phase shifted by a multiple of an angle α.
12. The system of claim 11 , wherein the angle α is determined based on a wavelength of the received signals and a distance between adjacent lines of the synthetic array.
13. The system of claim 11 , wherein the angle α is determined as:
α
=
-
2
π
d
λ
sin
θ
,
wherein λ is a wavelength of the received signals, and d is a distance between adjacent lines of the synthetic array.
14. The system of claim 11 , wherein a first line at an end of the synthetic array is phase shifted by N multiplied by α, and wherein a second line at an opposite end of the synthetic array is phase shifted by −N multiplied by α.