Antenna array and radar

Abstract

The embodiment of the present invention discloses an antenna array and a radar. The antenna array includes a receiving antenna array and a transmitting antenna array; the receiving antenna array includes a plurality of receiving antenna units arranged at intervals along a first direction, and each receiving antenna unit includes a plurality of receiving antennas arranged at intervals along a second direction; the transmitting antenna array includes a plurality of transmitting antennas arranged at intervals along a first direction and a second direction; one of the first direction and the second direction is a horizontal direction, and the other is a vertical direction. The embodiment of the present invention increases the number of receiving antennas and transmitting antennas in the vertical direction of the antenna array by arranging a plurality of receiving antenna units and a plurality of transmitting antennas in the antenna array, thereby making the angular resolution of the antenna array for height measurement smaller, improving the accuracy of the antenna array in height measurement, and solving the technical problem of poor accuracy of radar in the prior art when measuring height.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of radar, and in particular to an antenna array and a radar. Background Art

[0002] 4D imaging radar technology refers to the technology that uses a large radio frequency channel array to detect the relative speed, distance and direction of objects on the road, as well as the height of objects above the road. Existing 4D imaging radars generally use an antenna array consisting of a single row of receiving antennas and multiple columns of transmitting antennas to measure horizontal angles and vertical heights. When measuring height based on existing 4D imaging radars, the angular resolution of the measurement is relatively large due to the limitations of the antenna array structure. However, the larger the angular resolution, the lower the measurement accuracy. Therefore, the existing 4D imaging radars have poor accuracy when measuring height and are difficult to meet actual usage requirements. Summary of the invention

[0003] The embodiment of the present invention provides an antenna array and a radar. The embodiment of the present invention can improve the resolution of radar height measurement and solve the technical problem that the radar in the prior art has poor accuracy in height measurement.

[0004] In a first aspect, an embodiment of the present invention provides an antenna array, including: a receiving antenna array and a transmitting antenna array;

[0005] The receiving antenna array comprises a plurality of receiving antenna units arranged at intervals along a first direction, and each of the receiving antenna units comprises a plurality of receiving antennas arranged at intervals along a second direction;

[0006] The transmitting antenna array comprises a plurality of transmitting antennas arranged at intervals along the first direction and the second direction;

[0007] One of the first direction and the second direction is a horizontal direction, and the other is a vertical direction.

[0008] Preferably, the first direction is a vertical direction, and the distance between two adjacent receiving antenna units in the first direction is 3λ, wherein λ is the wavelength of an antenna operating frequency band.

[0009] Preferably, the spacing between the receiving antennas in the receiving antenna unit in the second direction is

[0010] Preferably, each receiving antenna unit further comprises a plurality of virtual receiving antenna units arranged at intervals below the receiving antenna unit;

[0011] Each of the virtual receiving antenna units includes a plurality of virtual receiving antennas arranged at intervals along the second direction.

[0012] Preferably, the spacing between two adjacent transmitting antennas in the first direction and the second direction is The distance between two adjacent virtual receiving antenna units in the first direction is The spacing between each receiving antenna unit and the adjacent virtual receiving antenna unit below the receiving antenna unit in the first direction is Where λ is the wavelength of the antenna operating frequency band.

[0013] Preferably, each of the receiving antenna units and the multiple virtual receiving antenna units below the receiving antenna unit form a receiving antenna subarray. If the spacing between two adjacent receiving antenna subarrays is greater than half a wavelength, when the antenna array is used to calculate the angle of the target, phase compensation is performed on the receiving signal of the subsequent receiving antenna subarray.

[0014] Preferably, the compensated phase is determined according to the spacing between each of the receiving antenna subarrays in the first direction.

[0015] Preferably, the compensated phase is determined according to the spacing between each receiving antenna subarray in the first direction and a correction factor, and the correction factor is used to correct the angle required to move the phase in the process of compensating the phase of the receiving antenna subarray.

[0016] Preferably, the correction factor is calculated in the following manner:

[0017] Calculating a first azimuth angle of a target object based on a signal wave received by a first receiving antenna subarray in the first direction, wherein the target object is located within a coverage range of the signal wave of the antenna array;

[0018] Calculating a second azimuth angle of the target object based on signal waves received by all receiving antenna subarrays;

[0019] A correction factor is determined according to the first azimuth angle and the second azimuth angle.

[0020] Preferably, in the process of calculating the second azimuth angle of the target object, phase shift is performed on other receiving antenna subarrays in the first direction except the first receiving antenna subarray, and the angles of phase shift of different receiving antenna subarrays are determined by the spacing between each receiving antenna subarray in the first direction.

[0021] Preferably, the number of the transmitting antennas is four, the number of the receiving antenna units is two, and the number of receiving antennas in each receiving antenna unit is eight.

[0022] Preferably, the receiving antenna and the transmitting antenna each include a plurality of array elements, and adjacent array elements are connected by a broken line, and the length of the broken line is half of the wavelength of the medium of the broken line.

[0023] In a second aspect, an embodiment of the present invention provides a radar, which is applied to the antenna array described in the first aspect.

[0024] As described above, an embodiment of the present invention discloses an antenna array and a radar. The antenna array includes a receiving antenna array and a transmitting antenna array; the receiving antenna array includes a plurality of receiving antenna units arranged at intervals along a first direction, and each receiving antenna unit includes a plurality of receiving antennas arranged at intervals along a second direction; the transmitting antenna array includes a plurality of transmitting antennas arranged at intervals along a first direction and a second direction; one of the first direction and the second direction is a horizontal direction, and the other is a vertical direction. The embodiment of the present invention increases the number of receiving antennas and transmitting antennas in the vertical direction of the antenna array by arranging a plurality of receiving antenna units and a plurality of transmitting antennas in the antenna array, and adopts an intermittent arrangement method, so that the angular resolution of the antenna array when measuring height becomes smaller, and the accuracy of the antenna array when measuring height is improved, thereby solving the technical problem that the radar in the prior art has poor accuracy when measuring height. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the structure of an antenna array provided in an embodiment of the present invention.

[0026] Figure 2 A schematic diagram of the structure of another antenna array provided in an embodiment of the present invention.

[0027] Figure 3 A schematic diagram of the structure of another antenna array provided in an embodiment of the present invention.

[0028] Figure 4 A schematic diagram of the structure of another antenna array provided in an embodiment of the present invention.

[0029] Figure 5 A schematic diagram of the MIMO principle provided by an embodiment of the present invention.

[0030] Figure 6 A schematic diagram of the structure of a MIMO antenna array provided in an embodiment of the present invention.

[0031] Figure 7 A schematic diagram of the structure of another MIMO antenna array provided in an embodiment of the present invention.

[0032] Figure 8 An equivalent schematic diagram of a MIMO antenna array provided by an embodiment of the present invention.

[0033] Fig. 9A frequency domain diagram of the vertical dimension of the MIMO antenna array provided in an embodiment of the present invention.

[0034] Fig.10 A schematic diagram of an array element structure of an antenna array provided in an embodiment of the present invention.

[0035] Fig.11 The present invention provides a radiation pattern of the E-plane and H-plane of a transmitting antenna.

[0036] Fig.12 The present invention provides a radiation pattern of the E-plane and H-plane of a receiving antenna.

[0037] Reference numerals:

[0038] Receiving antenna unit 10 , receiving antenna 101 , transmitting antenna 102 , virtual receiving antenna unit 20 , virtual receiving antenna 201 , array element 30 . DETAILED DESCRIPTION

[0039] The following description and accompanying drawings fully illustrate the specific embodiments of the present application so that those skilled in the art can practice them. The examples represent possible variations only. Unless explicitly required, separate components and functions are optional, and the order of operations can vary. The parts and features of some embodiments may be included in or replace the parts and features of other embodiments. The scope of the embodiments of the present application includes the entire scope of the claims, and all available equivalents of the claims. In this article, each embodiment may be represented individually or generally by the term "invention", which is only for convenience, and if more than one invention is disclosed in fact, it is not intended to automatically limit the scope of the application to any single invention or inventive concept. In this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, without requiring or implying any actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method or terminal device including a series of elements includes not only those elements, but also includes other elements that are not explicitly listed. The various embodiments are described in a progressive manner herein, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other. As for the structures, products, etc. disclosed in the embodiments, since they correspond to the parts disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

[0040] At present, in the existing 4D imaging radar technology, a single-row receiving antenna array is generally used in the antenna array, that is, a receiving antenna array composed of 4 receiving antennas RX1~RX4 arranged horizontally in a single row from left to right, and a transmitting antenna array composed of multiple columns and rows of transmitting antennas TX1~TX3. Among them, TX1 and TX3 are located on the same horizontal line and are separated by a certain horizontal distance, and TX2 is located between TX1 and TX3, and has a certain vertical distance from TX1 and TX3 in the vertical direction. RX1~RX4 and TX1~TX3 form a MIMO antenna array, where MIMO refers to a technology that uses multiple transmitting antennas and multiple receiving antennas at the transmitting end and the receiving end respectively, so that the signal is transmitted and received through multiple antennas at the transmitting end and the receiving end, thereby improving the communication quality. According to the MIMO principle, using the virtual aperture technology, since there is a horizontal distance between TX1 and TX3 in the horizontal direction, the receiving antennas RX1 to RX4 will be combined into a 2X4 receiving array in the horizontal direction (the receiving array has eight receiving antennas in the horizontal direction, four real receiving antennas RX1-RX4 and four virtual receiving antennas); in addition, since there is a vertical distance between TX2 and TX1 / TX3, TX2 and TX1 / TX3 can be combined into a 2X1 receiving array in the vertical direction (the receiving array has two rows of antennas in the vertical direction, one row of real receiving antennas RX1-RX4 and one row of virtual receiving antennas). With the cooperation of the receiving antenna array and the transmitting antenna array, the radar can not only realize the angle measurement in the horizontal direction, but also realize the height measurement in the vertical direction. However, since there are only two receiving antennas in the vertical direction in this antenna array structure (one real receiving antenna and one virtual receiving antenna), when measuring the height in the vertical direction, the angular resolution of the height measurement can only reach ±57.3° at most, and the measurement accuracy is poor, which is difficult to meet the actual measurement requirements.

[0041] Based on this, an embodiment of the present invention provides an antenna array and a radar to improve the measurement accuracy when using the antenna array to perform vertical height measurement.

[0042] An embodiment of the present invention provides an antenna array, the antenna array comprising: a receiving antenna array and a transmitting antenna array;

[0043] The receiving antenna array includes a plurality of receiving antenna units arranged at intervals along a first direction, and each receiving antenna unit includes a plurality of receiving antennas arranged at intervals along a second direction; the transmitting antenna array includes a plurality of transmitting antennas arranged at intervals along a first direction and a second direction; one of the first direction and the second direction is a horizontal direction, and the other is a vertical direction.

[0044] In this embodiment, the receiving antenna array includes a plurality of receiving antenna units 10 arranged at intervals along a first direction, and each receiving antenna unit 10 includes a plurality of receiving antennas 101 arranged at intervals along a second direction. The number of receiving antenna units 10 and the number of receiving antennas 101 in the receiving antenna unit 10 can be set according to actual needs. The spacing distance (i.e., the spacing) of each receiving antenna unit 10 can be equal or unequal. Currently, the spacing of each receiving antenna unit 10 is equal as an example, and the specific value of the spacing can be set according to actual needs. The spacing between two receiving antenna units 10 refers to the distance between the center phases of the two receiving antenna units 10, and can also be understood as the distance between the center phases of two receiving antennas located in the same straight line in the second direction in the two receiving antenna units 10. Similarly, the spacing distance (i.e., the spacing) of the receiving antennas 101 in the receiving antenna unit 10 can be equal or unequal. Currently, the spacing of each receiving antenna 101 is equal as an example, and the specific value of the spacing can be set according to actual needs. The spacing between two receiving antennas 101 refers to the distance between the center phases of the two receiving antennas. Optionally, the first antenna of each receiving antenna unit in the second direction can be connected in a straight line in the first direction, that is, the starting position of each receiving antenna unit in the first direction is the same. In the transmitting antenna array, a plurality of transmitting antennas 102 are arranged at intervals in the first direction and the second direction. Among them, the number of transmitting antennas 102 can be set according to actual needs. The spacing distance (i.e., the spacing) of each transmitting antenna 102 can be equal or unequal. Currently, the equal spacing of each transmitting antenna 102 is taken as an example, and the specific value of the spacing can be set according to actual needs. Among them, the spacing between two transmitting antennas 102 refers to the distance between the center phases of the two transmitting antennas 102. Among them, the first direction and the second direction are perpendicular to each other. In one embodiment, the first direction is a horizontal direction, and the second direction is a vertical direction. Or, the first direction is a vertical direction, and the second direction is a horizontal direction. In one embodiment, the transmitting antennas 102 can be connected to form an oblique line when arranged in two directions at intervals. In this case, there are two arrangements of the transmitting antenna array, one is from the upper left to the lower right (from the user's perspective), and the other is from the upper right to the lower left (from the user's perspective). The specific arrangement can be combined with the current usage requirements. In one embodiment, the arrangement from the upper right to the lower left is used as an example for description. In one embodiment, when the first direction is the vertical direction and the second direction is the horizontal direction, the structural diagram of the antenna array is as follows: Figure 1 As shown, when the first direction is the horizontal direction and the second direction is the vertical direction, the structural schematic diagram of the antenna array is as follows Figure 2 As shown. Need to explain, Figure 1 and Figure 2 These are just two exemplary antenna arrays and are not intended to limit the number and arrangement of antenna arrays.

[0045] The transmitting antenna 102 and the receiving antenna 101 mentioned in this embodiment are both composed of a plurality of array elements, where an array element refers to a radiation unit that constitutes an antenna. In one embodiment, a plurality of array elements are arranged in a vertical direction to form the antenna used in this embodiment.

[0046] It should be noted that the horizontal direction and vertical direction mentioned above are two relative directions. When the antenna array is placed along different directions, the horizontal direction and the vertical direction may change according to the placement direction. However, no matter how the placement direction changes, the perpendicular relationship between the first direction and the second direction does not change. Therefore, when the antenna array is placed in a certain direction, it can be achieved that one of the first direction and the second direction is a horizontal direction and the other is a vertical direction.

[0047] Exemplarily, when using an antenna array for measurement, the angular resolution can reflect the measurement accuracy of the antenna array. The angular resolution refers to the ability of an imaging system or system element (currently referring to the antenna array) to distinguish the minimum distance between two adjacent objects. The smaller the angular resolution, the higher the measurement accuracy. The more the number of receiving antennas 101 in the antenna array, the smaller the angular resolution when the antenna array measures height. The reason is that the number of receiving antennas 101 in the antenna array and the angular resolution of the height measurement have the following relationship:

[0048]

[0049] Among them, Δθ is the angular resolution, λ is the wavelength of the antenna working frequency band; N is the number of receiving antennas in the vertical direction; d is the spacing between the receiving antennas; θ is the position of the detected object. It can be understood that the angular resolution and the number of receiving antennas when using an antenna array for horizontal angle measurement are also applicable to formula (1), in which case N is the number of receiving antennas in the horizontal direction. It can be seen from formula (1) that when λ and θ are fixed, the more N, the smaller Δθ. Therefore, in this embodiment, by setting a plurality of receiving antenna units in the receiving antenna array of the antenna array, each receiving antenna unit 10 includes a plurality of receiving antennas 101, and setting a plurality of transmitting antennas 102 in the transmitting antenna array, and by setting the intervals in the first direction and the second direction, the number of receiving antennas 101 and transmitting antennas 102 can be increased in the vertical direction, thereby reducing the angular resolution of the antenna array in height measurement, thereby improving the measurement accuracy of the antenna array. In one embodiment, an exemplary description is given by taking the number of transmitting antennas 102 in the transmitting antenna array as four, the number of receiving antenna units 10 in the transmitting antenna array as two, and the number of receiving antennas 101 in each receiving antenna unit 10 as eight. In this case, the structural diagram of the antenna array is shown in FIG3. Figure 3The antenna array shown can maximize the layout space of the antenna array by arranging the antennas compactly up and down on the basis of ensuring the number of antennas (ie ensuring the measurement accuracy), thereby reducing the size occupied by the antenna array.

[0050] It should be further explained that, in theory, increasing the number of transmitting antennas 102 or increasing the number of receiving antennas 101 will improve the angular resolution in the same way. However, in actual use, since the system used by the radar using the antenna array for measurement requires that there can only be one transmitter, that is, only one local oscillator signal can be generated, and the energy of the local oscillator signal is fixed, the more transmitting antennas 102 there are, the weaker the energy allocated to each transmitting antenna 102, the lower the signal-to-noise ratio of the system, and the closer the distance that can be detected. However, multiple receivers can be set, and the energy requirement of the local oscillator signal required by each receiver is very low. Therefore, the local oscillator signal of the transmitter can be divided into many paths for the receiver to use, and the impact on the signal-to-noise ratio of the system is small (that is, the signal-to-noise ratio will not change much), and the detection distance will not be changed. Therefore, in the embodiment, when setting the number of receiving antennas 101 and transmitting antennas 102, the increase in the number of receiving antennas 101 is generally greater than the increase in the number of transmitting antennas 102.

[0051] In addition, it is necessary to further explain that, based on formula (1), for the antenna array, the spacing between the receiving antennas 101 will affect the size of the angular resolution. The larger the spacing between the receiving antennas, the smaller the angular resolution. However, the spacing between the receiving antennas will affect the maximum angular field of view of the antenna array. The maximum angular field of view refers to the angle of the maximum field of view that the antenna array can detect. The calculation formula for the maximum angular field of view is as follows:

[0052]

[0053] Among them, θ MAX is the maximum angular field of view of the antenna array. From formula (2), we can see that when λ is fixed, the larger d is, the larger θ is. MAX Therefore, in this embodiment, a reasonable spacing between the receiving antenna units and the receiving antennas can be set according to actual needs, so as to ensure the maximum angular field of view of the antenna array while ensuring the angular resolution.

[0054] In one embodiment, the first direction is a vertical direction, and the spacing between two adjacent receiving antenna units in the first direction is 3λ, where λ is the wavelength of the antenna working frequency band.

[0055] Exemplarily, the spacing between two adjacent receiving antenna units 10 in the first direction is 3λ. When the first direction is a vertical direction, the structure of the receiving antenna array is as follows: Figure 4As shown, at this time, the reason for setting the spacing between two adjacent receiving antenna units 10 to 3λ is that: in actual use, in order to ensure the strength of the received signal, the receiving antenna 101 needs a larger gain, so the number of array elements arranged in the vertical direction in each receiving antenna 101 cannot be too small. When the number of array elements in the receiving antenna 101 is large, the length of each receiving antenna 101 will be longer, resulting in an increase in the spacing between the center phases of the two adjacent receiving antennas 101 in the vertical direction, which cannot achieve the ideal Therefore, it is necessary to set a reasonable spacing between adjacent receiving antenna units 10 to ensure the detection accuracy of the antenna array. Currently, the spacing of the receiving antenna units 10 is set to 3λ, which can meet the requirements of the number of commonly used array elements of the receiving antenna for the spacing in the vertical direction.

[0056] In one embodiment, the spacing between the receiving antennas in the receiving antenna unit in the second direction is

[0057] For example, Figure 4 In the receiving antenna array, the horizontal distance between every two adjacent receiving antennas 101 is Where λ is the wavelength of the antenna operating frequency band. Set the spacing to The reason is that, according to formula (2), when the distance between the two receiving antennas 101 is When , the angular field of view of the antenna array can reach ±90°, that is, the maximum angular field of view is achieved. Therefore, the distance between the two receiving antennas 101 in the horizontal direction is set to The angular resolution of the antenna array can be improved while ensuring that the antenna array achieves a maximum angular field of view of ±90°.

[0058] As described above, an embodiment of the present invention provides an antenna array. The antenna array includes a receiving antenna array and a transmitting antenna array; the receiving antenna array includes a plurality of receiving antenna units arranged at intervals along a first direction, and each receiving antenna unit includes a plurality of receiving antennas arranged at intervals along a second direction; the transmitting antenna array includes a plurality of transmitting antennas arranged at intervals along a first direction and a second direction; one of the first direction and the second direction is a horizontal direction, and the other is a vertical direction. The embodiment of the present invention increases the number of receiving antennas and transmitting antennas in the vertical direction of the antenna array by arranging a plurality of receiving antenna units and a plurality of transmitting antennas in the antenna array, thereby making the angular resolution of the antenna array for height measurement smaller, thereby improving the accuracy of the antenna array for height measurement.

[0059] In one embodiment, each receiving antenna unit further includes a plurality of virtual receiving antenna units arranged at intervals below; each virtual receiving antenna unit includes a plurality of virtual receiving antennas arranged at intervals along the second direction.

[0060] In one embodiment, the receiving antenna array and the transmitting antenna array form a MIMO antenna array. Since the receiving antenna array includes multiple receiving antennas 101 and the transmitting antenna array includes multiple receiving antennas 101, the receiving antenna array and the transmitting antenna array can be used to form a MIMO antenna array. The MIMO antenna array can greatly improve the channel capacity and has extremely high spectrum utilization efficiency.

[0061] It should be further explained that, according to the MIMO technology, the effect of increasing the number of receiving antennas 101 can be achieved by simply increasing the number of transmitting antennas 102. For example, Figure 5 As shown, Figure 5 There are two transmitting antennas TX1 and TX2. The phase generated by the signal transmitted by TX1 on the four receiving antennas RX1, RX2, RX3 and RX4 is [0ω2ω3ω] (based on RX1). Since the second transmitting antenna TX2 is set at a position 4d away from TX1, any signal transmitted by TX2 has an additional path 4dsin(θ) compared with TX1. At this time, the phase of the signal transmitted by TX2 received by the four receiving antennas will have an additional phase shift of 4ω relative to the signal transmitted by TX1. The phase of the signal transmitted by TX2 received by the four RX antennas is [4ω5ω6ω7ω]. The phase sequence of the signals sent by TX1 and TX2 on the four RX antennas is connected in series to obtain the phase sequence [0ω2ω3ω4ω5ω6ω7ω]. This phase sequence is the same as the phase sequence obtained when using 1 transmitting antenna and eight receiving antennas, that is, when using four receiving antennas, after adding a transmitting antenna, four receiving antennas can be virtualized, that is, the effect of using eight receiving antennas can be simulated. At this time, it can be considered that four receiving antennas 101 are virtualized. The technology of virtualizing the receiving antenna can also be understood as virtual aperture technology.

[0062] Similarly, in this embodiment, since the transmitting antenna array has multiple transmitting antennas 102, and each transmitting antenna 102 is spaced apart along the first direction and the second direction, a MIMO antenna array can be formed according to the receiving antenna array and the transmitting antenna array, and more receiving antennas can be virtually generated in the receiving antenna array through a virtual aperture in the vertical direction, thereby increasing the number of receiving antennas in the vertical direction, and further improving the angular resolution of the antenna array when performing height measurement.

[0063] In one embodiment, the number of virtual receiving antennas 201 can be determined according to the number of transmitting antennas 101 and receiving antennas 102. Currently, two transmitting antennas 101 are used as an example for exemplary description. Figure 6, taking two receiving antenna units 10 as an example, at this time, for each receiving antenna unit 10, each receiving antenna 101 therein can simulate a virtual receiving antenna 201, and the arrangement of the virtual receiving antenna 201 is similar to that of the real receiving antenna 101. The virtual receiving antennas 201 on the same straight line in the second direction can form a virtual receiving antenna unit 20, and each virtual receiving antenna unit 20 is also arranged at intervals in the first direction. Based on this, it can be known that at least one virtual receiving antenna unit 20 will be generated under each receiving antenna unit 10, and each virtual receiving antenna unit 20 includes multiple virtual receiving antennas 201. When there are multiple virtual receiving antenna units 20, the multiple virtual receiving antenna units 20 are arranged at intervals in the first direction. Generally speaking, the total number of a receiving antenna unit 10 and the virtual receiving antenna units 20 thereunder is equal to the number of transmitting antennas. It can be understood that when the receiving antenna array and the transmitting antenna array form a MIMO antenna array, the number of receiving antennas 101 in the vertical direction of the receiving antenna array can be appropriately reduced, and the number of receiving antennas 101 can be compensated by the virtual receiving antennas 201 virtually generated in the MIMO antenna array, thereby improving the utilization rate of the receiving antennas 101 and ensuring the angular resolution while reducing the cost.

[0064] At present, the first direction is taken as the vertical direction for exemplary description. Since the transmitting antennas 102 are arranged at intervals in the horizontal direction and the vertical direction, a plurality of virtual receiving antenna units 20 arranged at intervals in the vertical direction are virtually generated below each receiving antenna unit 10, and each virtual receiving antenna unit 20 includes a plurality of virtual receiving antennas 201 arranged at intervals in the horizontal direction. For example, the number of transmitting antennas 102 in the transmitting antenna array is four. Figure 7 In the receiving antenna array shown in the figure, the number of receiving antenna units 10 in the receiving antenna array is two, and the number of receiving antennas 101 in each receiving antenna unit 10 is eight. At this time, according to the MIMO principle, each receiving antenna unit 10 will generate three virtual receiving antenna units 20 arranged at intervals in the vertical direction, and each virtual receiving antenna unit 20 includes eight virtual receiving antennas 201 arranged at intervals in the horizontal direction. The structure of the MIMO receiving antenna array is as follows: Fig. 9 shown.

[0065] As mentioned above, in this embodiment, the number of receiving antenna units in the vertical direction is increased by generating a virtual receiving antenna unit in the MIMO antenna array, thereby compensating for the number of receiving antennas in the vertical direction and improving the angular resolution of the antenna array when measuring height. Secondly, since the virtual receiving antenna unit is virtually generated, it is not necessary to reserve a setting space for the virtual receiving antenna unit in the actual antenna array. Therefore, the size of the antenna array can be reduced, and the antenna array can be miniaturized. On the other hand, the extra space can be used to increase the number of array elements of the transmitting antenna, thereby increasing the gain of the transmitting antenna and improving the signal-to-noise ratio of the antenna array.

[0066] In one embodiment, the distances between two adjacent transmitting antennas in the first direction and the second direction are both The distance between two adjacent virtual receiving antenna units in the first direction is The spacing between each receiving antenna unit and the adjacent virtual receiving antenna unit below the receiving antenna unit in the first direction is Where λ is the wavelength of the antenna operating frequency band.

[0067] In one embodiment, the spacing between two adjacent transmitting antennas 102 in the first direction and the second direction is set to Set to The purpose is to make the receiving antenna array generate virtual receiving antenna units 20, so that the spacing between two adjacent virtual receiving antenna units 20 in the first direction is The vertical distance between each receiving antenna unit 10 and the adjacent virtual receiving antenna unit 20 below the receiving antenna unit 10 is To ensure that the antenna array achieves the maximum angular field of view.

[0068] like Figure 7 In the MIMO antenna array shown, the spacing between two adjacent virtual receiving antenna units 20 in the first direction is The vertical distance between each receiving antenna unit 10 and the adjacent virtual receiving antenna unit 20 below the receiving antenna unit 10 is This ensures the maximum angular field of view of the antenna array while ensuring measurement accuracy.

[0069] In one embodiment, each receiving antenna unit and multiple virtual receiving antenna units below the receiving antenna unit form a receiving antenna subarray. If the spacing between two adjacent receiving antenna subarrays is greater than half a wavelength, when using the antenna array to calculate the angle of the target, phase compensation is performed on the receiving signal of the subsequent receiving antenna subarray.

[0070] It should be noted that, in this embodiment, in order to ensure the gain of the receiving antenna 101, the number of array elements 30 in each receiving antenna 101 cannot be too small, so a large interval needs to be set between each receiving antenna unit 10, which cannot meet the requirements of the MIMO principle. Figure 7 In the MIMO antenna array shown, the distances between two adjacent transmitting antennas 102 in the vertical and horizontal directions are both The distance between two adjacent virtual receiving antenna units 20 in the first direction is The vertical distance between each receiving antenna unit 10 and the adjacent virtual receiving antenna unit 20 below the receiving antenna unit 10 is According to the MIMO principle, the distance between the two receiving antenna units 10 and the virtual receiving antenna unit 20 is Add the distance between the virtual receiving antenna units 20 Therefore, the ideal interval between the two receiving antenna elements 10 is 2λ. Figure 7 In the MIMO antenna array shown, due to the limitation of the number of array elements, the interval between the two receiving antenna units 10 reaches 3λ, resulting in that in the MIMO antenna array, the spacing between the third virtual receiving antenna unit 20 and the second receiving antenna unit 10 is Not really This causes the MIMO antenna array to have angle ambiguity when measuring the azimuth angle of the target in the vertical direction. Figure 8 As shown, Figure 8 is an equivalent schematic diagram of a MIMO antenna array, where 1 represents a receiving antenna 101, X represents a transmitting antenna 102, and each grid represents an interval The 1 inside the quadrilateral is a virtual receiving antenna 201 generated according to the MIMO principle, the 1 outside the quadrilateral is a real receiving antenna 101, and 0 indicates no antenna. Figure 8 It can be seen that in the MIMO antenna array, the interval between the virtual receiving antenna unit 20 in the fourth row and the receiving antenna unit 10 in the fifth row reaches Therefore, regardless of whether the DBF algorithm or the FFT3rd algorithm is used, according to the principle of maximum angular field of view, the spacing between adjacent receiving antennas (including the receiving antenna 101 and the virtual receiving antenna 201) is greater than When calculating the azimuth angle of a target in the vertical direction, the MIMO antenna array will have two calculation results. These two calculation results cause the angle ambiguity problem. Figure 7 When the MIMO antenna array shown is simulated, the results obtained are as follows Fig. 9 The vertical dimension of the frequency domain is shown in Figure 2. Fig. 9In the example, since the interval between the virtual receiving antenna unit 20 in the fourth row and the receiving antenna unit 10 (real) in the fifth row is Therefore, when calculating the azimuth of the target, no matter whether the DBF algorithm or the FFT3rd algorithm is used, there will be two calculation results, which will be superimposed on the calculation results of the eight receiving antennas (including the two receiving antennas 101 and the six virtual receiving antennas 201) in the vertical direction in the form of side lobes, such as Fig. 9 As shown, in Fig. 9 There is only one main peak in the curve, and the curves without side lobes are The spectrum obtained by using DBF algorithm and FFT3rd for eight receiving antennas (i.e. Fig. 9 The DBF curve and FFT3rd curve in ), and the curve with side lobes is Figure 7 The MIMO antenna array shown uses the DBF algorithm and the FFT3rd algorithm to calculate the spectrum diagram (i.e. Fig. 9 In an ideal situation, the side lobes cannot reach the amplitude of the main lobe, so the angle calculation will not go wrong. However, in practical applications, the side lobes may cause the angle calculation error of the echo with weak signal-to-noise ratio, resulting in the azimuth calculation error of the target.

[0071] In order to avoid the problem of angle ambiguity, in this embodiment, if the distance between two adjacent receiving antenna subarrays is greater than half a wavelength, when using the antenna array to calculate the angle of the target, phase compensation is performed on the received signal of the subsequent receiving antenna subarray. Figure 7 For example, when using an antenna array to calculate the azimuth of a target, it is necessary to Figure 7 The virtual receiving antenna units 20 in the fourth row and the receiving antenna units 10 in the fifth row are phase compensated. Based on this, in the present embodiment, a compensation phase is set for each receiving antenna unit 10, so that when the MIMO antenna array is used to calculate the azimuth of the target, the compensation phase is used to perform phase compensation on each receiving antenna subarray to avoid the problem of angle ambiguity. Specifically, the compensation phase corresponding to each receiving antenna subarray is pre-calculated and saved. When the antenna array is subsequently used to calculate the azimuth of the target, phase compensation is performed by calling the compensation phase corresponding to each receiving antenna subarray. After that, the antenna array after phase compensation is used to calculate the azimuth of the target, thereby solving the problem of angle ambiguity. It can be understood that in the present embodiment, the first receiving antenna subarray does not need to be phase compensated.

[0072] In one embodiment, the compensated phase is determined according to the spacing between each receiving antenna subarray in the first direction.

[0073] Exemplarily, when calculating the phase required to be compensated for each receiving antenna subarray, it is determined according to the distance between each receiving antenna subarray in the vertical direction. Figure 7 As an example, according to the MIMO principle, the distance between the two antennas is When the phase shift between the antennas is ω, the interval between the virtual receiving antenna unit 20 in the fourth row and the receiving antenna unit 10 in the fifth row is The phase shift of the virtual receiving antenna unit 20 in the fourth row and the receiving antenna unit 10 in the fifth row is 3ω. Therefore, the phase shift of the receiving antenna unit 10 in the fifth row is required to be 2ω, so that the interval between the virtual receiving antenna unit 20 in the fourth row and the receiving antenna unit 10 in the fifth row is That is, 2ω is the phase that needs to be compensated for the second receiving antenna array. The corresponding compensation phase of the second receiving antenna array is 2ω. Figure 7 When the MIMO antenna array shown calculates the azimuth angle of the target, it is necessary to compensate the phase of the second receiving antenna subarray by 2ω to solve the angle ambiguity problem.

[0074] It can be understood that in actual use, the number of receiving antenna units 10 in the vertical direction of the receiving antenna array may be greater than two. For example, when there are three receiving antenna units 10, there will be three receiving antenna subarrays in the MIMO antenna array. Therefore, it is necessary to further compensate the phase of the third receiving antenna subarray. Since the interval between the virtual receiving antenna unit 20 in the last row of the second receiving antenna subarray and the receiving antenna unit 10 of the third receiving antenna subarray is also However, when compensating the phase of the second receiving antenna subarray, the phase of the second receiving antenna subarray is shifted by 2ω. Therefore, for the third receiving antenna subarray, it is necessary to shift the phase by 2ω and then shift it by 2ω, so that the interval between the receiving antenna unit 10 of the third receiving antenna subarray after the phase shift and the last virtual receiving antenna unit 20 of the second receiving antenna subarray after the phase shift is That is, the phase that needs to be compensated for the third receiving antenna subarray is 4ω. When there are four, five or six receiving antenna subarrays in the MIMO antenna array, the phase that needs to be compensated for each receiving antenna subarray is similar. Each receiving antenna subarray needs to move 2ω more than the phase moved by the previous receiving antenna subarray. The phase that needs to be compensated for the Nth receiving antenna subarray is (N-1)×2ω, that is, the compensation phase corresponding to the N receiving antenna subarrays is (N-1)×2ω, which is proportional to the distance between each receiving antenna subarray and the first receiving antenna subarray in the vertical direction.

[0075] In the above, the phase required to be compensated for each receiving antenna subarray is determined according to the distance of each receiving antenna subarray in the vertical direction, so that when the MIMO antenna array is used to calculate the azimuth of the target later, the phase required to be compensated for the receiving antenna subarray can be called to perform phase compensation on the receiving antenna subarray, so that the interval between the virtual receiving antenna unit and the receiving antenna unit is It meets the requirements of the MIMO principle, thus avoiding the problem of angle ambiguity when subsequently calculating the azimuth of the target.

[0076] When the antenna array is used to measure the azimuth of the target object, the signal wave of each receiving antenna unit can be obtained, wherein the signal received by the first receiving antenna subarray in the first direction does not need to be phase compensated, and the signals received by the subsequent (second or third...) receiving antenna subarrays can be phase compensated according to the preset compensation phase, so that the interval between adjacent receiving antenna subarrays after phase compensation is After phase compensation, the azimuth of the target object can be calculated based on the signal waves of all receiving antenna subarrays (including the signal wave of the first receiving antenna subarray that has not been phase compensated and the signal waves of other receiving antenna subarrays after phase compensation) to obtain a more accurate azimuth.

[0077] In one embodiment, the compensated phase is determined according to the spacing between the receiving antenna subarrays in the first direction and a correction factor, and the correction factor is used to correct the angle required to move the phase during the process of compensating the phase of the receiving antenna subarrays.

[0078] Exemplarily, since the phase center of the receiving antenna subarray is actually inaccurate, if the corresponding compensation phase is determined only according to the distance of each receiving antenna subarray in the vertical direction, the calculated compensation phase will be inaccurate. For example, for the second receiving antenna subarray, the phase that needs to be moved may be a little more or a little less than 2ω. Therefore, it is necessary to further introduce a correction factor to calibrate the phase that needs to be moved by the receiving antenna subarray to obtain an accurate compensation phase. In this embodiment, after determining the phase that needs to be moved by the receiving antenna subarray according to the distance of the receiving antenna subarray in the vertical direction (currently recorded as the initial compensation phase), the correction factor is further used to calibrate the phase that needs to be moved, so as to accurately obtain the compensation phase corresponding to each receiving antenna subarray.

[0079] Exemplarily, the calculation method of the correction factor is not currently limited. In one embodiment, the correction factor is calculated by: calculating the first azimuth of the target object based on the signal wave received by the first receiving antenna subarray in the first direction, wherein the target object is located within the signal wave coverage range of the antenna array; calculating the second azimuth of the target object based on the signal waves received by all receiving antenna subarrays; and determining the correction factor based on the first azimuth and the second azimuth. Specifically, in this embodiment, Figure 7 Taking the MIMO antenna array shown as an example, when calculating the first azimuth angle, a target object is first placed at a preset position. It can be understood that the target object is located within the signal wave coverage range of the antenna array. In one embodiment, in order to facilitate calculation, the preset position can be set in the 0° direction of the MIMO antenna array. In this embodiment, the preset position is not limited. Afterwards, the azimuth angle of the target object is estimated by using the DBF algorithm or the FFT3rd algorithm using the received signal wave of the first receiving antenna subarray in the MIMO antenna array, and the azimuth angle is recorded as the first azimuth angle. When the target object is placed in the 0° direction of the MIMO antenna array, the first azimuth angle should theoretically be 0° at this time, but due to the existence of errors, the first azimuth angle may be an angle close to 0°, such as 1° or -1°.

[0080] After calculating the first azimuth, it is necessary to further calculate the second azimuth. In the present embodiment, the second azimuth is calculated based on the received signal waves of all the receiving antenna subarrays. In one embodiment, in the process of calculating the second azimuth of the target object, the phases of the receiving antenna subarrays other than the first receiving antenna subarray are shifted in the first direction, and the angles of phase shift of different receiving antenna subarrays are determined by the spacing of the receiving antenna subarrays in the first direction. That is, the phases of the receiving antenna subarrays other than the first receiving antenna subarray are shifted, and the azimuth of the target object is calculated based on the received signal waves of all the receiving antenna subarrays after the phase shift. This azimuth is the second azimuth. Specifically, Figure 7 Taking the MIMO antenna array in as an example, after calculating the first azimuth angle, due to Figure 7The MIMO antenna array includes a first receiving antenna subarray and a second antenna subarray. Therefore, the phase of the second receiving antenna subarray other than the first receiving antenna subarray is further moved. The phases of different receiving antenna subarrays are moved at different angles. The angle is the initial compensation phase of the corresponding receiving antenna subarray. The initial compensation phase is multiplied by the corresponding correction factor to obtain the compensation phase. In this embodiment, the initial compensation phase of the second receiving antenna subarray is 2ω. The reason why the initial compensation phase is 2ω can be referred to the above process of determining the compensation phase, which is not repeated in this embodiment. After the initial compensation phase of the phase of the second receiving antenna subarray is moved, the first receiving antenna subarray and the second receiving antenna subarray after the phase shift are used to calculate the azimuth of the target object, and the azimuth is recorded as the second azimuth. It can be understood that if the receiving antenna array includes more than two receiving antenna subarrays, it is necessary to move the phases of the other receiving antenna subarrays except the first receiving antenna subarray, that is, the initial compensation phase required to be moved by the Nth receiving antenna subarray is (N-1)×2ω. Then, the second azimuth angle of the target object is calculated using the first receiving antenna subarray and all other receiving antenna subarrays whose phases are shifted by the corresponding initial compensation phase.

[0081] It can be understood that the calculation method of the first azimuth angle and the second azimuth angle is an implemented technical means and is not described separately at present.

[0082] After calculating the first azimuth angle and the second azimuth angle, a correction factor can be calculated based on the first azimuth angle and the second azimuth angle, so that the correction factor can be used to calibrate the phase required to be moved by the receiving antenna subarray to obtain the compensation phase corresponding to each receiving antenna subarray. In one embodiment, the calculation formula of the correction factor is:

[0083] AX+B(1-X)=0

[0084] Wherein, A is the first azimuth angle, B is the second azimuth angle, and X is the correction factor.

[0085] After obtaining the correction factor, the correction factor is multiplied by the phase that each receiving antenna subarray needs to move, thereby obtaining the phase that each receiving antenna subarray needs to compensate, that is, the compensation phase. That is, for the Nth receiving antenna subarray in the MIMO antenna array, the corresponding compensation phase calculation formula is:

[0086] K N =X×(N-1)×2ω

[0087] Among them, K N is the compensation phase corresponding to the Nth receiving antenna subarray.

[0088] After the compensation phase is calculated, the compensation phase is saved so that when the antenna array is used to calculate the azimuth of the target later, the compensation phase corresponding to each receiving antenna subarray can be called, and the compensation phase is used to compensate the phase of the corresponding receiving antenna subarray. After that, the receiving antenna array after phase compensation is used to calculate the azimuth of the target in the vertical direction.

[0089] As described above, the embodiment of the present invention calibrates the phase that needs to be moved for each receiving antenna subarray by using a correction factor, thereby accurately obtaining the compensation phase corresponding to each receiving antenna subarray, so that after the receiving antenna subarray is subsequently compensated using the compensation phase, the precision and accuracy of the azimuth angle calculated by the antenna array can be further improved.

[0090] In one embodiment, the receiving antenna and the transmitting antenna both include a plurality of array elements, and adjacent array elements are connected by a fold line, and the length of the fold line is half of the wavelength of the medium of the fold line.

[0091] In this embodiment, both the receiving antenna and the transmitting antenna include a plurality of array elements 30, and adjacent array elements 30 are connected by fold lines. For example, when the receiving antenna array includes two receiving antenna units 10, each receiving antenna unit includes eight receiving antennas 101, and the transmitting antenna array includes four transmitting antennas 102, each receiving antenna 101 includes 10 array elements 30, and each transmitting antenna 102 includes eight array elements 30, the structure of the antenna array is as follows: Fig.10 As shown, the receiving antenna 101 and the transmitting antenna 102 both include a plurality of array elements 30 , and adjacent array elements 30 are connected by fold lines.

[0092] It can be understood that by connecting each array element 30 with a zigzag line, the size of the receiving antenna 101 and the transmitting antenna 102 can be reduced, thereby further reducing the area of ​​the antenna array. In one embodiment, the length of the zigzag line is half the wavelength of the medium of the zigzag line, thereby increasing the half-power lobe width of the H plane of the receiving antenna 101 and the transmitting antenna 102, thereby expanding the detection range of the antenna array. In this embodiment, the directional patterns of the E plane and the H plane of the transmitting antenna 102 and the receiving antenna 101 are respectively as shown in FIG. Fig.11 as well as Fig.12 shown.

[0093] As described above, the embodiments of the present invention reduce the sizes of the receiving antenna and the transmitting antenna by connecting the array elements in the receiving antenna and the transmitting antenna through a broken line, miniaturize the area of ​​the antenna array, and on the other hand, the excess space can be used to increase the number of array elements, thereby increasing the gain of the transmitting antenna and improving the signal-to-noise ratio of the radar product.

[0094] The embodiment of the present invention further provides a radar, which includes an antenna array as described above. The application scenario of the radar is not currently limited, such as application in fields such as drones that require radar for detection and measurement. The embodiment of the present invention can increase the number of receiving antennas and transmitting antennas in the vertical direction of the antenna array by setting multiple receiving antenna units and multiple transmitting antennas in the antenna array, thereby making the angular resolution of the antenna array for height measurement smaller and improving the accuracy of the antenna array in height measurement. In addition, when the antenna array is a MIMO antenna array, the size occupied by the antenna array can be further reduced, and the excess space can be used to increase the number of array elements of the transmitting antenna, thereby increasing the gain of the transmitting antenna and improving the signal-to-noise ratio of the antenna array.

[0095] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the embodiments of the present invention are not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the embodiments of the present invention. Therefore, although the embodiments of the present invention are described in more detail through the above embodiments, the embodiments of the present invention are not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the embodiments of the present invention, and the scope of the embodiments of the present invention is determined by the scope of the appended claims.

Claims

1. An antenna array, It is characterized in that include: a receiving antenna array and a transmitting antenna array; The receiving antenna array comprises a plurality of receiving antenna units arranged at intervals along a first direction, and each of the receiving antenna units comprises a plurality of receiving antennas arranged at intervals along a second direction; The transmitting antenna array includes a plurality of transmitting antennas arranged at intervals along the first direction and the second direction; the first direction is a vertical direction, the second direction is a horizontal direction, and the spacing between two adjacent receiving antenna units in the first direction is 3 ,in, is the wavelength of the antenna working frequency band, and the spacing between two adjacent transmitting antennas in the first direction and the second direction is .

2. The antenna array according to claim 1, It is characterized in that The spacing between the receiving antennas in the receiving antenna unit in the second direction is .

3. The antenna array according to claim 1, It is characterized in that Each receiving antenna unit also includes a plurality of virtual receiving antenna units arranged at intervals below the receiving antenna unit; Each of the virtual receiving antenna units includes a plurality of virtual receiving antennas arranged at intervals along the second direction.

4. The antenna array according to claim 3, It is characterized in that The distance between two adjacent virtual receiving antenna units in the first direction is , the spacing between each receiving antenna unit and the adjacent virtual receiving antenna unit below the receiving antenna unit in the first direction is ,in, is the wavelength of the antenna operating frequency band.

5. The antenna array according to claim 4, It is characterized in that Each receiving antenna unit and multiple virtual receiving antenna units below the receiving antenna unit form a receiving antenna subarray. If the spacing between two adjacent receiving antenna subarrays is greater than half a wavelength, when using the antenna array to calculate the angle of the target, phase compensation is performed on the receiving signal of the subsequent receiving antenna subarray.

6. The antenna array according to claim 5, It is characterized in that The compensated phase is determined according to the spacing between the receiving antenna subarrays in the first direction.

7. The antenna array according to claim 5, It is characterized in that The compensated phase is determined according to the spacing between the receiving antenna subarrays in the first direction and a correction factor, and the correction factor is used to correct the angle required to move the phase during the process of compensating the phase of the receiving antenna subarray.

8. The antenna array according to claim 7, It is characterized in that The correction factor is calculated as follows: Calculating a first azimuth angle of a target object based on a signal wave received by a first receiving antenna subarray in the first direction, wherein the target object is located within a coverage range of the signal wave of the antenna array; Calculating a second azimuth angle of the target object based on signal waves received by all receiving antenna subarrays; A correction factor is determined according to the first azimuth angle and the second azimuth angle.

9. The antenna array according to claim 8, It is characterized in that In the process of calculating the second azimuth angle of the target object, phase shift is performed on other receiving antenna subarrays except the first receiving antenna subarray in the first direction, and the angles of phase shift of different receiving antenna subarrays are determined by the spacing between the receiving antenna subarrays in the first direction.

10. The antenna array according to claim 1, It is characterized in that The number of the transmitting antennas is four, the number of the receiving antenna units is two, and the number of receiving antennas in each receiving antenna unit is eight.

11. The antenna array according to claim 1, It is characterized in that The receiving antenna and the transmitting antenna both include a plurality of array elements, and adjacent array elements are connected by a broken line, wherein the length of the broken line is half of the medium wavelength of the broken line.

12. A radar, It is characterized in that The radar comprises the antenna array according to any one of claims 1-11.

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