The present invention relates to antennas, and more particularly, to a high-resolution antenna array system.
Regarding technology nowadays, using radar to detect the position of an object to facilitate the confirmation of the target object has become an important development technology. The development of radar technology accelerates the maturity of, for example, the automatic driving technology of automobiles. A radar detects an object through an antenna. The uniform linear array (ULA) and the sparse linear array (SLA) are both common antenna arrangement characteristics. When a limited number of antennas are applied for multi-target detection, in the circumstance using the SLA arrangement, the signal superposition of the side lobe often causes a strength which is closed to that of the reflection signal of the main lobe, resulting in more than one target detection angle and leading to an erroneous detection. Generally, the ULA arrangement is used, so as to prevent the signal superposition of the side lobe through the low side lobe characteristic of ULA arrangement.
In order to fulfill the condition of high-angle resolution of the antenna at the same time, with a limited number of antenna units, the ULA arrangement increases the length of the antenna array by increasing the interval distance between the antenna units, so as to adjust the aperture of the antenna array, thereby increasing the resolution of the antenna angle. However, the antenna interval of the ULA arrangement will be greater than half a wavelength and reduce the resolvable angle range, causing an angle ambiguity of the radar in the detection of the angle of the target object, failing to accurately judge the angle of arrival (AoA) of the target object.
The present invention discloses a high-resolution antenna array system. With the distribution design of the antenna array, the present invention facilitates a high angular resolution and prevents angle ambiguity.
For achieving the aforementioned objectives, an embodiment in accordance with the present invention provides a high-resolution antenna array system for detecting the angle and distance of at least one target object, the antenna array system comprising a first physical antenna array, a second physical antenna array, an equivalent antenna array, and a processor. The first physical antenna array comprises at least one first physical antenna. The second physical antenna array comprises a plurality of second physical antennas. The first and second physical antenna arrays are configured to detect the target object and carry out transmission and receiving of signal. The equivalent antenna array is obtained by multiplying the positions of the first physical antenna array by the positions of the second antenna array. The equivalent antenna array comprises a first equivalent antenna group having a plurality of first antenna units arranged at equal intervals and a second equivalent antenna group having a plurality of second antenna units arranged at equal intervals, wherein the second equivalent antenna group is translated by a unit interval with respect to the first equivalent antenna group, such that each first antenna unit and each second antenna unit are staggered and arranged at intervals along the same direction. The interval between each two neighboring first antenna units and the interval between each two neighboring second antenna units are N times the unit interval, wherein N is a positive integer, and N is larger than or equal to (≥) 3. The processor is coupled with the first physical antenna array and the second physical antenna array, through which the processor obtains a target signal reflected by the target object. The target signal comprises a first frequency spectrum information from the first equivalent antenna group, and a second frequency spectrum information from the second equivalent antenna group. The processor carries out a calibration according to the first frequency spectrum information and the second frequency spectrum information and obtains a precise phase difference, thereby obtaining an accurate angle of arrival of the target signal through the precise phase difference.
Another embodiment in accordance with the present invention provides a high-resolution antenna array system for detecting the angle and the distance of at least one target object, the antenna array system comprising a first physical antenna array, a second physical antenna array, and a processor. The first physical antenna array comprises a first antenna and a second antenna. The interval between the first antenna and the second antenna is 2N times a unit interval, wherein N is a positive integer, and N is larger than or equal to 3. The second physical antenna array comprises a third antenna, a fourth antenna, a fifth antenna, and a sixth antenna orderly arranged along the same direction. The interval between the third antenna and the fourth antenna is the unit interval, the interval between the fourth antenna and the fifth antenna is (N-1) times the unit interval, and the interval between the fifth antenna and the sixth antenna is the unit interval, wherein the first physical antenna array and the second physical antenna array are configured to detect the target object, carry out transmission and receiving of signal, and obtain a target signal from the target object. The processor is coupled with the first physical antenna array and the second physical antenna array, through which the processor obtains the target signal. Therein, the processor processes the target signal to generate a first frequency spectrum information and a second frequency spectrum information and carries out a calculation with the first and the second frequency spectrum information to generate a precise phase difference, so as to obtain an accurate angle of arrival of the target signal through the precise phase difference.
Another embodiment in accordance with the present invention provides a high-resolution antenna array system for detecting the angle and the distance of at least one target object, the antenna array system comprising a first physical antenna array, a second physical antenna array, and a processor. The first physical antenna array comprises a first antenna and a second antenna. The interval between the first antenna and the second antenna is a unit interval. The second physical antenna array comprises a third antenna, a fourth antenna, a fifth antenna, and a sixth antenna orderly arranged at equal intervals along the same direction. The interval between the third antenna, the fourth antenna, the fifth antenna, and the sixth antenna are N times the unit interval, wherein N is a positive integer, and N is larger than or equal to 3. Therein, the first physical antenna array and the second physical antenna array are configured to detect the target object, carry out transmission and receiving of signal, and obtain a target signal from the target object. The processor is coupled with the first physical antenna array and the second physical antenna array, through which the processor obtains the target signal. Therein, the processor processes the target signal to generate a first frequency spectrum information and a second frequency spectrum information and carries out a calculation with the first and the second frequency spectrum information to generate a precise phase difference, so as to obtain an accurate angle of arrival of the target signal through the precise phase difference.
Another embodiment in accordance with the present invention provides a high-resolution antenna array system for detecting the angle and the distance of at least one target object, the antenna array system comprising a first physical antenna array, a second physical antenna array, and a processor. The first physical antenna array comprises a first antenna and a second antenna. The interval between the first antenna and the second antenna is N times of a unit interval, wherein N is a positive integer, and N is larger than or equal to 3. The second physical antenna array comprises a third antenna, a fourth antenna, a fifth antenna, and a sixth antenna orderly arranged along the same direction. The interval between the third antenna and the fourth antenna is the unit interval, the interval between the fourth antenna and the fifth antenna is (2N-1) times the unit interval, and the interval between the fifth antenna and the sixth antenna is the unit interval. Therein, the first physical antenna array and the second physical antenna array are configured to detect the target object, carry out transmission and receiving of signal, and obtain a target signal from the target object. The processor is coupled with the first physical antenna array and the second physical antenna array, through which the processor obtains the target signal. Therein, the processor processes the target signal to generate a first frequency spectrum information and a second frequency spectrum information and carries out a calculation with the first and the second frequency spectrum information to generate a precise phase difference, so as to obtain an accurate angle of arrival of the target signal through the precise phase difference.
With such configuration, the high-resolution antenna array system, through the equivalent antenna array obtained from the distribution design of the first physical antenna array and the second physical antenna array, is able to increase the length of the antenna array under the condition of a limited number of the antenna units, so as to increase the aperture of the antenna array, thereby increasing the angle resolution of antenna.
Further, with the precise phase difference generated by the processor calculating the first frequency spectrum information and the second frequency spectrum information from the equivalent antenna array, the present invention prevents the angle ambiguity and obtains the accurate angle of arrival of the target signal.
The aforementioned and further advantages and features of the present invention will be understood by reference to the description of the preferred embodiment in conjunction with the accompanying drawings where the components are illustrated based on a proportion for explanation but not subject to the actual component proportion.
Referring to
The first physical antenna array 10 comprises at least one first physical antenna, and the second physical antenna array 20 comprises a plurality of second physical antennas. The first physical antenna array 10 and the second physical antenna array 20 are configured to detect the target object and carry out the transmission and receiving of signal.
Referring to
The interval between the first antenna 11 and the second antenna 12 is 2N times a unit interval d. The interval between the third antenna 21 and the fourth antenna 22 is the unit interval d. The interval between the fourth antenna 22 and the fifth antenna 23 is (N-1) times the unit interval d. The interval between the fifth antenna 23 and the sixth antenna 24 is the unit interval d. Therein, the unit interval d is larger than or equal to (≥) ½λ, and λ is the wavelength of the transmission signal. N is a positive integer, and N is larger than or equal to 3. In the embodiment, N is equal to 4.
In the embodiment, the first physical antenna array 10 is the transmission antenna, and the second physical antenna array 20 is the receiving antenna. However, the configuration is allowed to be exchanged, such that the first physical antenna array 10 is the receiving antenna, and the second physical antenna array 20 is the transmission antenna. In the embodiment, the equivalent antenna array 40 is allowed to be a physical antenna or a combination of a physical antenna and a virtual antenna. Also, the first physical antenna array 10 is allowed to be extended multiple times at equal intervals, so as to include four antennas or six antennas, etc. Similarly, the second physical antenna array 20 is allowed to be extended multiple times at equal intervals, so as to include eight antennas or twelve antennas, etc.
Further, according to the description above, the equivalent antenna array 40 in the present invention is obtained by multiplication and combination of the positions of the first physical antenna array 10 and the second physical antenna array 20. Taking the embodiment as an example, regarding the formation of the equivalent antenna array 40, the first antenna 11 is multiplied by the third antenna 21, the fourth antenna 22, the fifth antenna 23, and the sixth antenna 24, so as to generate an array whose positions and distributions are identical to that of the third antenna 21, the fourth antenna 22, the fifth antenna 23, and the sixth antenna 24. Then, the second antenna 12 is multiplied by the third antenna 21, the fourth antenna 22, the fifth antenna 23, and the sixth antenna 24, so as to generate another group of virtual array whose distributions are identical to that of the third antenna 21, the fourth antenna 22, the fifth antenna 23, and the sixth antenna 24, but is translated by 2N times the distance of the unit interval d (equal to the interval between the first antenna 11 and the second antenna 12) with respect to the third antenna 21. Finally, the two arrays above are combined to form the equivalent antenna array 40 shown in the lower part of
Notably, the angle resolution of the regular ULA antenna array is decided according to the aperture of the antenna array. Therefore, if the angle resolution of the antenna array is to be increased, the number of antennas has to be increased, thereby increasing the whole antenna array. However, an ordinary hardware has a fixed size, which is unable to hold infinite numbers of antennas. Therefore, a longer equivalent antenna array 40 is able to be obtained through the combination of physical and virtual antennas, so as to increase the aperture of the antenna array, thereby increasing the angle resolution.
Also as shown by
In the embodiment, the second equivalent antenna group B is translated by a unit interval d with respect to the first equivalent antenna group A, so that each first antenna unit a and each second antenna unit b are staggered and arranged at equal intervals along the same direction. In the embodiment, the interval between each two neighboring first antenna units a and the interval between each two neighboring second antenna units b are N times the unit interval d. With such configuration, the original equivalent antenna array 40 is divided into two ULA arrays, namely the first equivalent antenna group A and the second equivalent antenna group B.
Through the equivalent antenna array 40 obtained from the combination of the first physical antenna array 10 and the second physical antenna array 20, the processor 30 obtains a target signal 31 reflected by the target object.
Referring to
Furthermore, the processor 30 comprises a calibration model 32 and a precise phase model 33. The processor 30 inputs an ambiguous phase obtained from the first frequency spectrum information 311 and the second frequency spectrum information 312 into the calibration model 32 to obtain a calibrated value and further inputs the calibrated value into the precise phase model 33 to obtain the precise phase difference.
For further information, the calibration model 32 is shown as the following formula:
wherein, “k” represents the calibrated value, “round” represents the function rounded to the nearest integer, “N” represents the multiple of the unit interval d, “ϕ” represents the initial phase variation quantity of the target object detected by the first equivalent antenna group A and the second equivalent antenna group B “SA(ϕ)” represents the signal strength of the first equivalent antenna group A, “SB(ϕ)” represents the signal strength of the second equivalent antenna group B, and “
” represents the ambiguous phase difference.
The precise phase model 33 is shown as the following formula:
Δθ=(ϕ+2kπ)/N, wherein “Δθ” represents the precise phase difference.
In the embodiment, the first frequency spectrum information 311 comprises the phase variation quantity ϕ and the signal strength SA(ϕ), the second frequency spectrum information 312 comprises the phase variation quantity ϕ and the signal strength SB(ϕ). Notably, because the phase variation quantity obtained by the first equivalent antenna group A and the second equivalent antenna group B correspond to the identical target object, the phase variation quantity ϕ of them shall be identical as well.
After obtaining the signal strength SA(ϕ) and signal strength SB(ϕ), the processor carries out the calculation of the formula
to obtain the ambiguous phase difference and then inputs the ambiguous phase difference into the calibration model 32 to obtain the calibrated value k. Next, the processor 30 inputs the calibrated value k into the precise phase model 33 to obtain the precise phase difference Δθ.
Notably, when under the ideal circumstances without noise interference, the ambiguous phase difference and the precise phase difference Δθ shall be identical. However, in practical situation, the phase difference calculated from the signal strength SA(ϕ) and the signal strength SB(ϕ) includes the noise, so that the precise phase difference is unable to be obtained under the possible effect thereof. Therein, if a calculation of
is directly carried out to obtain k, the obtained k will not be an integer. However, the k has to practically be a positive integer. Therefore, through the processing of the calibration model 32, the k is able to be obtained as an integer, and such calibrated value k is used for subsequent process.
Besides, because the interval between each first antenna unit a of the first equivalent antenna group A and the interval between each second antenna unit b of the second equivalent antenna group B are larger than or equal to ½λ, the object beyond the detection range of the antenna angle will have the same performance as the object within the angle range. In other words, the phase variation quantity ϕ obtained from the first frequency spectrum information 311 and the second frequency spectrum information 312 shall actually be ϕ+2kπ, causing the ambiguity of the phase variation quantity ϕ. Therefore, through the processing of the precise phase model 33, the precise phase difference Δθ is obtained.
For example, the angle of arrive of the target object is 46 degrees, and the multiple N of the unit interval d is 4. The processor 30 firstly obtains the ambiguous phase difference
from the first frequency spectrum information 311 and the second frequency spectrum information 312. Due to the effect of noise, the ambiguous phase difference is inputted into asind
to obtain an inaccurate angle of arrival as 49.7471 degrees. Therefore, the processor 30 inputs the ambiguous phase difference into the calibration model 32
obtaining the calibrated value k=1. Then, the calibrated value k in inputted into the precise phase model 33 Δθ=(ϕ+2kπ)/N, obtaining the precise phase difference Δθ=0.71887π. Finally, the processor 30 inputs the precise phase difference Δθ into arcsind(Δθ), obtaining an accurate angle of arrival as 45.9555 degrees, which is more accurate compared to the angle of arrival obtain with the ambiguous phase difference.
Referring to
In this embodiment, the interval between the first antenna 11 and the second antenna 12 is the unit interval d. The interval between the third antenna 21, the fourth antenna 22, the fifth antenna 23, and the sixth antenna 24 are N times the unit interval d. Therein, the unit interval d is larger than or equal to ½λ, and λ is the wavelength of the transmission signal. N is a positive integer, and N is larger than or equal to 3, In this embodiment, N is equal to 4.
In this embodiment, the first physical antenna array 10 is the transmission antenna, and the second physical antenna array 20 is the receiving antenna. However, the configuration is allowed to be exchanged, such that the first physical antenna array 10 is the receiving antenna, and the second physical antenna array 20 is the transmission antenna. In this embodiment, the equivalent antenna array 40 is allowed to be a physical antenna or a combination of a physical antenna and a virtual antenna. Also, the first physical antenna array 10 is allowed to be extended multiple times at equal intervals, so as to include four antennas or six antennas, etc. Similarly, the second physical antenna array 20 is allowed to be extended multiple times at equal intervals, so as to include eight antennas or twelve antennas, etc.
Further, in this embodiment, the equivalent antenna array 40 is formed of following configuration. The first antenna 11 is multiplied by the third antenna 21, the fourth antenna 22, the fifth antenna 23, and the sixth antenna 24, so as to generate an array whose positions and distributions are identical to that of the third antenna 21, the fourth antenna 22, the fifth antenna 23, and the sixth antenna 24. Then, the second antenna 12 is multiplied by the third antenna 21, the fourth antenna 22, the fifth antenna 23, and the sixth antenna 24, so as to generate another group of virtual array whose distributions are identical to that of the third antenna 21, the fourth antenna 22, the fifth antenna 23, and the sixth antenna 24, but is translated by the distance of the unit interval d (equal to the interval between the first antenna 11 and the second antenna 12) with respect to the third antenna 21. Finally, the two arrays above are combined to form the equivalent antenna array 40.
Referring to
In this embodiment, the interval between the first antenna 11 and the second antenna 12 is N times the unit interval d. The interval between the third antenna 21 and the fourth antenna 22 is the unit interval d. The interval between fourth antenna 22 and the fifth antenna 23 is (2N-1) times the unit interval d. The interval between the fifth antenna 23 and the sixth antenna 24 is the unit interval d. Therein, the unit interval d is larger than or equal to ½λ, and λ is the wavelength of the transmission signal. N is a positive integer, and N is larger than or equal to 3. In this embodiment, N is equal to 4.
In this embodiment, the first physical antenna array 10 is the transmission antenna, and the second physical antenna array 20 is the receiving antenna. However, the configuration is allowed to be exchanged, such that the first physical antenna array 10 is the receiving antenna, and the second physical antenna array 20 is the transmission antenna. In this embodiment, the equivalent antenna array 40 is allowed to be a physical antenna or a combination of a physical antenna and a virtual antenna. Also, the first physical antenna array 10 is allowed to be extended multiple times at equal intervals, so as to include four antennas or six antennas, etc. Similarly, the second physical antenna array 20 is allowed to be extended multiple times at equal intervals, so as to include eight antennas or twelve antennas, etc.
Further, in this embodiment, the equivalent antenna array 40 is formed of following configuration, the first antenna 11 is multiplied by the third antenna 21, the fourth antenna 22, the fifth antenna 23, and the sixth antenna 24, so as to generate an array whose positions and distributions are identical to that of the third antenna 21, the fourth antenna 22, the fifth antenna 23, and the sixth antenna 24. Then, the second antenna 12 is multiplied by the third antenna 21, the fourth antenna 22, the fifth antenna 23, and the sixth antenna 24, so as to generate another group of virtual array whose distributions are identical to that of the third antenna 21, the fourth antenna 22, the fifth antenna 23, and the sixth antenna 24, but is translated by N times the distance of the unit interval d (equal to the interval between the first antenna 11 and the second antenna 12) with respect to the third antenna 21. Finally, the two arrays above are combined to form the equivalent antenna array 40.
The aforementioned embodiments mainly explain that the physical antenna array is allowed to have different arrangement distributions, and all structures capable of forming the equivalent antenna structure in accordance with the present invention fall into the equivalent scope of the claims of the present invention.
With the foregoing configuration, effects and functions of the present invention will be illustrated below.
Through the equivalent antenna array 40 obtained from the distribution design of the first physical antenna array 10 and the second physical antenna array 20, the present invention is able to increase the length of the antenna array under the condition of a limited number of the antenna units, so as to increase the aperture of the antenna array, thereby increasing the angle resolution of antenna.
Also, through the calibration model 32 and the precise phase model 33 of the processor 30, the first frequency spectrum information 311 and the second frequency spectrum information 322 from the equivalent antenna array 40 are calculated to generate the precise phase difference, so that the present invention prevents the issue of angle ambiguity when the interval between the antenna units is larger than half wavelength, thereby obtaining the accurate angle of arrival of the target signal 31.
Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.
Number | Date | Country | Kind |
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111133104 | Sep 2022 | TW | national |