CN112154571A - Array antenna, signal processing method thereof and millimeter wave radar - Google Patents

Array antenna, signal processing method thereof and millimeter wave radar Download PDF

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Publication number
CN112154571A
CN112154571A CN201980033270.3A CN201980033270A CN112154571A CN 112154571 A CN112154571 A CN 112154571A CN 201980033270 A CN201980033270 A CN 201980033270A CN 112154571 A CN112154571 A CN 112154571A
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antenna
antennas
equivalent
receiving
adjacent
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CN112154571B (en
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饶雄斌
鲁洪昊
林立
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SZ DJI Technology Co Ltd
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SZ DJI Technology Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
    • H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

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  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)

Abstract

An array antenna, a signal processing method thereof and a millimeter wave radar are provided, wherein the array antenna comprises a substrate (1) and N arranged on the substrate1First antennas (2) arranged at equal intervals and N arranged on the substrate2The second antennas (3) are arranged at equal intervals, the first antenna is one of a receiving antenna and a transmitting antenna, and the second antenna is the other one of the receiving antenna and the transmitting antenna; n is a radical of1The first antenna is arranged at N2One side of the second antenna, N1、N2Is a natural number, and N1≥2，N2≧ 2, and the first antenna and the second antenna are substantially parallel, and the distance d between adjacent first antennas1Comprises the following steps: md2D, the spacing d of adjacent second antennas2Comprises the following steps: 2d or 4d, wherein
Figure DDA0002783675190000011
M is a natural number, and M is more than or equal to 2 and less than or equal to N2And λ is the operating wavelength of the array antenna. Through the layout strategy of the first antenna and the second antenna, the angle measurement precision of the millimeter wave radar can be greatly improved, and therefore the performance of the millimeter wave radar is improved.

Description

Array antenna, signal processing method thereof and millimeter wave radar
Technical Field
The application relates to the field of antennas, in particular to an array antenna, a signal processing method thereof and a millimeter wave radar.
Background
In recent years, research in the automobile industry focuses on assistant driving and automatic driving, and in order to realize assistant driving and automatic driving, a reliable sensor is required to sense the surrounding environment of a vehicle. The commonly used vehicle sensor comprises a millimeter wave radar, a laser radar, an ultrasonic radar and a camera, and compared with other vehicle sensors, the millimeter wave radar has the advantages of long detection distance, strong penetrating power and capability of working in severe environments such as night, rainy days, frost and the like. Therefore, the millimeter wave radar also becomes a core sensor of the driving assistance and automatic driving system.
The millimeter wave radar can measure distance, speed and angle of a target, and due to the characteristics of the measurement principle of the millimeter wave radar, the measurement precision of the distance and the speed is far higher than that of the angle, and the angle measurement precision becomes a short plate of the performance of the millimeter wave radar to a certain extent. Therefore, improving the angle measurement accuracy is very important for improving the performance of the millimeter wave radar.
The angle measurement precision of the millimeter wave radar is related to the total length of the base line, and the larger the total length of the base line is, the larger the angle measurement precision of the radar is. The length of the base line is equal to the product of the distance between the receiving antennas and the number of the receiving antennas, and the angle measurement precision can be improved by improving the distance between the antennas and the number of the antennas. However, in practical applications, the antenna pitch is generally fixed to half the wavelength in order to simultaneously ensure that the angle measurement range is as large as possible. The number of receiving antennas becomes the only variable affecting the accuracy of the angle measurement (i.e., the angle measurement resolution). The traditional millimeter wave radar is limited by factors such as the size requirement and the cost requirement of a radar board, the number of receiving antennas is limited, and the angle measurement precision of the millimeter wave radar is difficult to further improve due to the difficulty in improving the number of actual antennas.
Disclosure of Invention
The application provides an array antenna, a signal processing method thereof and a millimeter wave radar.
Specifically, the method is realized through the following technical scheme:
according to a first aspect of the present application, there is provided an array antenna for millimeter wave radar operation, the array antenna comprising a substrate, N arranged on the substrate1First antennas arranged at intervals at equal intervals and N arranged on substrate2The first antenna is one of a receiving antenna and a transmitting antenna, and the second antenna is the other one of the receiving antenna and the transmitting antenna;
N1the first antenna is arranged at N2One side of the second antenna, N1、N2Is a natural number, and N1≥2，N2≧ 2, and the first antenna and the second antenna are substantially parallel, and the distance d between adjacent first antennas1Comprises the following steps: md2D, the spacing d of adjacent second antennas2Comprises the following steps: 2d or 4 d;
wherein ,
Figure BDA0002783675170000021
m is a natural number, and M is more than or equal to 2 and less than or equal to N2And λ is the operating wavelength of the array antenna.
According to a second aspect of the present application, there is provided a millimeter wave radar including:
an antenna substrate; and
the array antenna is arranged on the antenna substrate and comprises N arranged on the antenna substrate1First antennas arranged at intervals at equal intervals and N arranged on antenna substrate2The first antenna is one of a receiving antenna and a transmitting antenna, and the second antenna is the other one of the receiving antenna and the transmitting antenna;
N1the first antenna is arranged at N2One side of the second antenna, N1、N2Is a natural number, and N1≥2，N2≧ 2, and the first antenna and the second antenna are substantially parallel, and the distance d between adjacent first antennas1Comprises the following steps: md2D, the spacing d of adjacent second antennas2Comprises the following steps: 2d or 4 d;
wherein ,
Figure BDA0002783675170000022
m is a natural number, and M is more than or equal to 2 and less than or equal to N2λ is the operating wavelength of the array antenna;
the transmitting antenna is used for transmitting microwave signals, the receiving antenna is used for receiving echo signals, and the millimeter wave radar can determine position information of the obstacle according to the echo signals; .
According to a third aspect of the present application, there is provided a movable platform comprising:
a control system; and
in the millimeter wave radar according to the second aspect of the present application, the control system is in communication connection with the millimeter wave radar, and the millimeter wave radar sends the position information of the detected obstacle to the control system.
According to a fourth aspect of the present application, there is provided an array antenna signal processing method for millimeter wave radar operation, the array antenna including a plurality of transmitting antennas and a plurality of receiving antennas, and the plurality of transmitting antennas being provided at one side of the plurality of receiving antennas, the transmitting antennas being substantially parallel to the receiving antennas, wherein the transmitting antennas operate based on a time division mode in which the plurality of transmitting antennas alternately operate in sequence at preset time intervals, and the array antennas form an equivalent transmitting antenna and an equivalent receiving antenna; the method comprises the following steps:
obtaining a complex value of each equivalent receiving antenna;
determining a first antenna vector according to the arrangement sequence of the equivalent receiving antennas and the complex values of the equivalent receiving antennas;
obtaining the distance between adjacent equivalent receiving antennas;
and if the distance between the adjacent equivalent receiving antennas is greater than a preset threshold value, zero padding is carried out between the complex values of the adjacent equivalent receiving antennas in the first antenna vector, and a second antenna vector is obtained.
According to the technical scheme provided by the embodiment of the application, a plurality of first antennas which are arranged at equal intervals and a plurality of second antennas which are arranged at equal intervals are arranged on a substrate, one of the first antennas and the second antennas is used as a transmitting antenna, the other one of the first antennas and the second antennas is used as a receiving antenna, and an array antenna is designed in a mode that a Multi-transmitting antenna is matched with a Multi-receiving antenna (Multi-Input Multi-Output); and the distance between adjacent first antennas is designed to be Nd2D, spacing d of adjacent second antennas2The design is 2d or 4d, and the angle measurement precision of the millimeter wave radar can be greatly improved through the layout strategy of the first antenna and the second antenna, so that the performance of the millimeter wave radar is improved; meanwhile, the distance between the antennas is increased, and each antenna can bear more subarrays, so that the antenna gain is increased.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive labor.
FIG. 1 is a schematic diagram of a prior art receiving antenna for detecting a target object;
fig. 2 is a schematic structural diagram of an array antenna in an embodiment of the present application;
fig. 3 is a schematic structural diagram of an array antenna in another embodiment of the present application;
fig. 4 is an operation diagram of a transmitting antenna in a time division mode of an array antenna in another embodiment of the present application;
fig. 5 is an equivalent antenna schematic diagram of the array antenna shown in fig. 2 in a time division mode;
fig. 6 is an equivalent antenna schematic diagram of the array antenna shown in fig. 3 in a time division mode;
fig. 7 is a flowchart illustrating a method of processing an array antenna signal according to an embodiment of the present application;
fig. 8 is a schematic diagram of the array antenna of fig. 5 after the equivalent receiving antenna has been zero-padded;
fig. 9 is a schematic diagram of the array antenna shown in fig. 6 after the equivalent receiving antenna is zero-padded.
Reference numerals:
1: a substrate; 2: a first antenna; 3: a second antenna; 4: a virtual receive antenna; 5: a zero-filling antenna.
Detailed Description
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.
It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, such information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present application. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context.
Figure BDA0002783675170000041
Wherein λ is the operating wavelength of the millimeter-wave radar antenna, N is the number of antennas, d is the antenna spacing, and θ is the angle at which the target object is located, that is, the arrival angle of the echo, see fig. 1. As can be seen from the calculation formula of the angle measurement accuracy, there are λ, N, d, and θ as parameters for determining the angle measurement accuracy. Lambda is determined by the chosen millimeter wave frequency and is limited by the requirements of laws and regulations, which cannot be freely selected, and theta is determined by actual conditions, and only N and d are left as parameters capable of improving the angle measurement accuracy.
In practical applications, the millimeter wave radar needs to consider the angle measurement range FOV in addition to the angle measurement accuracy, wherein,
Figure BDA0002783675170000042
as can be seen from the calculation formula of FOV, when d is λ/2, the one-sided FOV can reach 90 ° at maximum, and therefore, it is necessary to ensure that the minimum antenna spacing d is λ/2 to ensure that the FOV covers [ -90 °, +90 ° ]]。
In addition, generally, the larger the number K of sub-arrays of antennas, the larger the antenna gain F. Wherein,
Figure BDA0002783675170000051
from the calculation formula of F, F → K when θ → 0. The higher F, the larger the farthest detection distance directly in front of the millimeter wave radar. As K increases, d increases, causing the FOV to decrease. Generally, if the number of subarrays is K, d will reach K λ/2.
Therefore, the antenna design of the millimeter wave radar needs to balance the angle measurement accuracy, the angle measurement range FOV, and the number K of sub-arrays of the antenna.
In practical applications, increasing the number of actual antennas often means increasing the size of the radar product, increasing the product cost, and increasing the power consumption of the product. The negative effects caused by the increase of the number of the actual antennas are more, so that the method is not an ideal scheme; on the other hand, the angle measurement precision, the angle measurement range FOV and the number K of antenna subarrays are mutually contradictory, and in practical design, the mutual mismatch is easily considered.
In this respect, a plurality of first antennas arranged at equal intervals and a plurality of second antennas arranged at equal intervals are arranged on a substrate, one of the first antennas and the second antennas is used as a transmitting antenna, the other one is used as a receiving antenna, and an array antenna is designed in a mode that a plurality of transmitting antennas are matched with a plurality of receiving antennas; and the distance between adjacent first antennas is designed to be Nd2D, spacing d of adjacent second antennas2The design is 2d or 4d, and the angle measurement precision of the millimeter wave radar can be greatly improved through the layout strategy of the first antenna and the second antenna, so that the performance of the millimeter wave radar is improved; meanwhile, the distance between the antennas is increased, and each antenna can bear more subarrays, so that the antenna gain is increased.
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that, in the following examples and embodiments, features may be combined with each other without conflict.
Referring to fig. 2 and fig. 3, an embodiment of the present application provides an array antenna for millimeter wave radar operation, where the array antenna may include a substrate 1, and N disposed on the substrate 11 First antennas 2 arranged at equal intervals and N arranged on the substrate 12And the second antennas 3 are arranged at equal intervals. Wherein the first antenna 2 is a receiving antenna andone of the transmitting antennas, the second antenna 3 is the other of the receiving antenna and the transmitting antenna. That is, the first antenna 2 is a receiving antenna, and the second antenna is a transmitting antenna; alternatively, the first antenna 2 is a transmitting antenna and the second antenna 3 is a receiving antenna.
In this example, N1A first antenna 2 is arranged at N2One side of the second antenna 3, N1、N2Is a natural number, and N1≥2，N2Not less than 2. Alternatively, the first antenna 2 includes two, and the second antenna 3 includes four; of course, the number of the first antenna 2 and the second antenna 3 may be other.
The first antenna 2 and the second antenna 3 are substantially parallel to each other, N of the present embodiment1The first antennas 2 are approximately parallel to each other, N2The second antennas 3 are also substantially parallel to each other. Further, the spacing d of adjacent first antennas 21Comprises the following steps: nd (neodymium)2D, M is a natural number, and 2. ltoreq. M. ltoreq.N2. Spacing d of adjacent second antennas 32Comprises the following steps: 2d or 4d of the total weight of the alloy,
Figure BDA0002783675170000061
λ is the operating wavelength of the array antenna.
It should be understood that the array antenna of the embodiments of the present application may be a patch antenna. Optionally, the first antenna and the second antenna are both disposed on the substrate 1 by using a printing process; of course, the first antenna and the second antenna may be disposed on the substrate by other processes.
In this embodiment, the transmitting antenna in the array antenna operates based on a time-division mode (time-division modulation), so that the number of virtual antennas is increased in a time-division manner, and the angle measurement accuracy of the millimeter wave radar is further improved. Specifically, in the time division mode, a plurality of transmitting antennas sequentially and alternately operate at preset time intervals. For example, referring to fig. 4, the array antenna includes a transmitting antenna 1 and a transmitting antenna 2, and the transmitting antenna 1 and the transmitting antenna 2 alternately operate in sequence at a preset time interval. The size of the preset time interval can be set according to needs.
When the transmitting antenna is based on the time division mode, the array antenna forms an equivalent transmitting antenna and an equivalent receiving antenna, and d is the distance between the minimum adjacent receiving antennas in the equivalent receiving antenna in the time division mode. Specifically, when the transmitting antennas are based on the time division mode, the transmitting antennas except the transmitting antennas adjacent to the receiving antenna in the plurality of transmitting antennas are translated to the position of the transmitting antennas adjacent to the receiving antenna to form an equivalent transmitting antenna. And the plurality of receiving antennas are wholly translated by the first distance to obtain a plurality of virtual receiving antennas 4, the number of the virtual receiving antennas 4 is equal to that of the receiving antennas, and the plurality of receiving antennas and the plurality of virtual receiving antennas 4 jointly form an equivalent receiving antenna. The first distance is the product of the difference obtained by subtracting 1 from the number of the transmitting antennas and the distance between the adjacent transmitting antennas.
For example, in some embodiments, the first antenna 2 is a transmitting antenna, the second antenna 3 is a receiving antenna, and the first distance is equal to (N)1-1)*(Md2-d). Wherein N is1The first antenna 2 except the first antenna 2 adjacent to the second antenna 3 in the first antenna 2 is translated to the position of the first antenna 2 adjacent to the second antenna 3 to form an equivalent transmitting antenna, and N is2The second antenna 3 is integrally translated by the first distance to obtain N2Root virtual receiving antenna 4, N2A second antenna 3 and N2The root virtual receive antennas 4 together form an equivalent receive antenna.
Further, with N1＝2、N2＝4、
Figure BDA0002783675170000071
For example, an equivalent transmitting antenna and an equivalent receiving antenna formed in the time division mode are explained.
Referring to fig. 2, M is 2, and the distance d between adjacent first antennas 21Is composed of
Figure BDA0002783675170000072
Spacing d of adjacent second antennas 32Is 2d, i.e. d2λ. In time division mode, the transmitting antenna on the left side in fig. 2 is shifted to the right
Figure BDA0002783675170000073
So that the two transmitting antennas are equivalent to one equivalent transmitting antenna; for the receiving antenna, the distance between the transmitting antennas is
Figure BDA0002783675170000074
Corresponding to each receiving antenna also translating towards the right
Figure BDA0002783675170000075
The new position virtualizes 4 virtual receive antennas 4, and 4 receive antennas and 4 virtual receive antennas 4 form equivalent receive antennas, as shown in fig. 5. That is, the physical antenna design of 2 transmitting antennas and 4 receiving antennas can be equivalent to a virtual antenna form of 1 transmitting antenna and 8 receiving antennas, and the number of the equivalent receiving antennas is multiplied, so that the angle measurement precision of the millimeter wave radar is also approximately doubled; meanwhile, the distance between the minimum adjacent receiving antenna in the equivalent receiving antennas is
Figure BDA0002783675170000076
Thereby ensuring that the FOV can still cover [ -90 °, +90 ° ]]。
Referring to fig. 3, M is 3, and the distance d between adjacent first antennas 21Is composed of
Figure BDA0002783675170000077
Spacing d of adjacent second antennas 32Is 2d, i.e. d2λ. In time division mode, the transmitting antenna on the left side in fig. 3 is shifted to the right
Figure BDA0002783675170000078
So that the two transmitting antennas are equivalent to one equivalent transmitting antenna; for the receiving antenna, the distance between the transmitting antennas is
Figure BDA0002783675170000079
Corresponding to each receiving antenna also translating towards the right
Figure BDA00027836751700000710
The new position virtualizes 4 virtual receive antennas 4, and 4 receive antennas and 4 virtual receive antennas 4 form equivalent receive antennas, as shown in fig. 6. That is, the physical antenna design of 2 transmitting antennas and 4 receiving antennas can be equivalent to a virtual antenna form of 1 transmitting antenna and 8 receiving antennas, and the number of the equivalent receiving antennas is multiplied, so that the angle measurement precision of the millimeter wave radar is also approximately doubled; meanwhile, the distance between the minimum adjacent receiving antenna in the equivalent receiving antennas is
Figure BDA00027836751700000711
Thereby ensuring that the FOV can still cover [ -90 °, +90 ° ]]。
Because of the reciprocity of the transmit and receive antennas, in other embodiments the first antenna is a receive antenna, the second antenna is a transmit antenna, and the first spacing is (N)2-1) × 2d or a first pitch (N)2-1) 4 d. Wherein N is2The second antennas except the second antenna adjacent to the first antenna are translated to the position of the second antenna adjacent to the first antenna to form an equivalent transmitting antenna, and N1Integrally translating the first antenna by the first distance to obtain N1Root virtual receiving antenna 4, N1A first antenna and N1The root virtual receive antennas 4 together form an equivalent receive antenna. The implementation process of the equivalent transmitting antenna and the equivalent receiving antenna formed in the time division mode of this embodiment is similar to that of the above embodiment, and is not described herein again.
Further, optionally, the first antenna 2 comprises a plurality of series of sub-arrays; optionally, the second antenna 3 comprises a multi-string sub-array; optionally, the first antenna 2 comprises a plurality of series of sub-arrays, and the second antenna 3 also comprises a plurality of series of sub-arrays. Because the adjacent antenna spacing of the first antenna 2 and the second antenna 3 is increased, the design space of a single antenna is larger, namely, each antenna can bear more serial sub-arrays, and compared with the antenna design only with a single serial sub-array, the antenna design of the multiple serial sub-arrays can increase the antenna gain. For example, the first antenna 2 includes 3 series of sub-arrays, and the second antenna 3 includes 2 series of sub-arrays.
In the array antenna of this embodiment, the transmitting antenna is configured to transmit a microwave signal, the microwave signal is reflected by a target object (e.g., an obstacle) and then received by the receiving antenna, and the position information of the target object can be determined according to the microwave signal received by the receiving antenna.
In addition, the embodiment of the present application further provides a signal processing method for an array antenna used for millimeter wave radar operation, where the array antenna of the present embodiment includes a plurality of transmitting antennas and a plurality of receiving antennas, the plurality of transmitting antennas are disposed on one sides of the plurality of receiving antennas, and the transmitting antennas and the receiving antennas are substantially parallel. The transmitting antennas work based on a time division mode, under the time division mode, a plurality of transmitting antennas work alternately in sequence according to a preset time interval, and the array antennas form equivalent transmitting antennas and equivalent receiving antennas. The structure of the array antenna of this embodiment is similar to that of the array antenna of the above embodiments, and is not described herein again.
In the following embodiments, each of the equivalent receiving antennas is referred to as an equivalent receiving antenna.
Referring to fig. 7, the array antenna signal processing method for millimeter wave radar operation may include steps S701 to S704.
In step S701, a complex value of each equivalent receiving antenna is obtained.
In step S702, a first antenna vector is determined according to the arrangement order of the equivalent receiving antennas and the complex values of the equivalent receiving antennas.
In step S703, the distance between adjacent equivalent receiving antennas is obtained.
In step S704, if the distance between the adjacent equivalent receiving antennas is greater than the predetermined threshold, zero padding is performed between the complex values of the adjacent equivalent receiving antennas in the first antenna vector to obtain a second antenna vector.
The size of the preset threshold may be designed as required, and optionally, the preset threshold is greater than or equal to twice the minimum value among the distances between the adjacent equivalent receiving antennas.
Referring to fig. 5, the 8 equivalent receiving antennas from left to right are equivalent receiving antennas 1, and so onAn effective receiving antenna 2, an equivalent receiving antenna 3, an equivalent receiving antenna 4, an equivalent receiving antenna 5, an equivalent receiving antenna 6, an equivalent receiving antenna 7, and an equivalent receiving antenna 8. The complex values of the equivalent antennas are a1, a2, a3, a4, a5, a6, a7, and a8, respectively, and the complex values of the antennas are obtained in the prior art, which is not described in detail in this application. The first antenna vector a determined at step S702 is [ a1, a2, a3, a4, a5, a6, a7, a8]. The distance between the equivalent receiving antenna 1 and the equivalent receiving antenna 2, the distance between the equivalent receiving antenna 7 and the equivalent receiving antenna 8 are λ, the distance between the equivalent receiving antenna 2 and the equivalent receiving antenna 3, the distance between the equivalent receiving antenna 3 and the equivalent receiving antenna 4, the distance between the equivalent receiving antenna 4 and the equivalent receiving antenna 5, the distance between the equivalent receiving antenna 5 and the equivalent receiving antenna 6, and the distance between the equivalent receiving antenna 6 and the equivalent receiving antenna are λ
Figure BDA0002783675170000091
The minimum value among the distances between adjacent equivalent receiving antennas is
Figure BDA0002783675170000092
Since the distance between the equivalent receiving antenna 1 and the equivalent receiving antenna 2 and the distance between the equivalent receiving antenna 7 and the equivalent receiving antenna 8 are twice the distance between other adjacent equivalent receiving antennas, that is, the distance between the equivalent receiving antenna 1 and the equivalent receiving antenna 2 and the distance between the equivalent receiving antenna 7 and the equivalent receiving antenna 8 are twice the minimum value of the distances between the adjacent equivalent receiving antennas, which is equivalent to that there is one antenna between the equivalent receiving antenna 1 and the equivalent receiving antenna 2 and between the equivalent receiving antenna 7 and the equivalent receiving antenna 8, respectively, it is necessary to add one null-filling antenna 5 between the equivalent receiving antenna 1 and the equivalent receiving antenna 2 and between the equivalent receiving antenna 7 and the equivalent receiving antenna 8, as shown in fig. 8. That is, in the first antenna vector a, zero padding is performed between a1 and a2 and between a7 and a8, respectively, and the second antenna vector B after zero padding is obtained as [ a1,0, a2, a3, a4, a5, a6, a7,0, a8]。
Referring to fig. 6, from left to right, 8 equivalent receiving antennas are respectively providedEquivalent receiving antenna 1, equivalent receiving antenna 2, equivalent receiving antenna 3, equivalent receiving antenna 4, equivalent receiving antenna 5, equivalent receiving antenna 6, equivalent receiving antenna 7, equivalent receiving antenna 8. The complex values of the equivalent antennas are a1, a2, a3, a4, a5, a6, a7, and a8, respectively, and the complex values of the antennas are obtained in the prior art, which is not described in detail in this application. The first antenna vector a determined at step S702 is [ a1, a2, a3, a4, a5, a6, a7, a8]. The distance between the equivalent receiving antenna 1 and the equivalent receiving antenna 2, the distance between the equivalent antenna 2 and the equivalent antenna 3, the distance between the equivalent antenna 6 and the equivalent antenna 7, the distance between the equivalent receiving antenna 7 and the equivalent receiving antenna 8 are all lambda, the distance between the equivalent receiving antenna 3 and the equivalent receiving antenna 4, the distance between the equivalent receiving antenna 4 and the equivalent receiving antenna 5 and the distance between the equivalent receiving antenna 5 and the equivalent receiving antenna 6 are all lambda
Figure BDA0002783675170000093
The minimum value among the distances between adjacent equivalent receiving antennas is
Figure BDA0002783675170000094
Since the distance between the equivalent receiving antenna 1 and the equivalent receiving antenna 2, the distance between the equivalent antenna 2 and the equivalent antenna 3, the distance between the equivalent antenna 6 and the equivalent antenna 7, and the distance between the equivalent receiving antenna 7 and the equivalent receiving antenna 8 are twice as long as the distance between other adjacent equivalent receiving antennas, that is, the distance between the equivalent receiving antenna 1 and the equivalent receiving antenna 2, the distance between the equivalent antenna 2 and the equivalent antenna 3, the distance between the equivalent antenna 6 and the equivalent antenna 7, and the distance between the equivalent receiving antenna 7 and the equivalent receiving antenna 8 are twice as long as the minimum value among the distances between the adjacent equivalent receiving antennas, which is equivalent to one antenna being empty between the equivalent receiving antenna 1 and the equivalent receiving antenna 2, between the equivalent antenna 2 and the equivalent antenna 3, between the equivalent antenna 6 and the equivalent antenna 7, and between the equivalent receiving antenna 7 and the equivalent receiving antenna 8, therefore, it is necessary to perform a process between the equivalent receiving antenna 1 and the equivalent receiving antenna 2, between the equivalent antenna 2 and the equivalent antenna 3, between the equivalent antenna 6 and the equivalent antenna 7,A zero-padding antenna 5 is added between the equivalent receiving antenna 7 and the equivalent receiving antenna 8, as shown in fig. 9. That is, in the first antenna vector a, zero padding is performed between a1 and a2, between a2 and a3, between a6 and a7, and between a7 and a8, respectively, so that zero-padded second antenna vector B ═ a1,0, a2,0, a3, a4, a5, a6,0, a7,0, a8]。
The number of the antennas of the equivalent receiving antenna after zero padding is further improved, and therefore the angle measurement precision is further improved.
Additionally, in some embodiments, the array antenna signal processing method for millimeter wave radar operation further comprises: and measuring the angle of the object according to the second antenna vector. When the object angle is measured according to the second antenna vector, specifically, the second antenna vector is processed by Fast Fourier Transform (FFT), and then the object angle is measured according to the FFT-processed second antenna vector. The process of measuring the angle of an object based on the antenna vector and FFT is prior art and is not specifically described in this application. It should be understood that other position information of the object, such as object position coordinates, may also be measured from the second antenna vector.
The array antenna of this embodiment can use on millimeter wave radar, and this application embodiment still provides a millimeter wave radar, and this millimeter wave radar can include antenna substrate and array antenna, and wherein, array antenna locates on the antenna substrate, and array antenna is including locating N on the antenna substrate1First antennas arranged at intervals at equal intervals and N arranged on antenna substrate2And the second antennas are arranged at equal intervals, the first antenna is one of the receiving antenna and the transmitting antenna, and the second antenna is the other one of the receiving antenna and the transmitting antenna. N is a radical of1The first antenna is arranged at N2One side of the second antenna, N1、N2Is a natural number, and N1≥2，N2Not less than 2. The first antenna and the second antenna are substantially parallel, and a distance d between adjacent first antennas1Comprises the following steps: md2D, the spacing d of adjacent second antennas2Comprises the following steps: 2d or 4 d. Wherein,
Figure BDA0002783675170000101
m is a natural number, and M is more than or equal to 2 and less than or equal to N2And λ is the operating wavelength of the array antenna. In this embodiment, the transmitting antenna of the array antenna is used for transmitting a microwave signal, the receiving antenna of the array antenna is used for receiving an echo signal, and the millimeter wave radar can determine the position information of the obstacle according to the echo signal.
The antenna substrate is equivalent to the substrate of the array antenna of the above embodiment, and the structures and operating principles of the first antenna and the second antenna of the array antenna are the same as those of the first antenna and the second antenna of the array antenna of the above embodiment, and are not described herein again.
The embodiment of the application further provides a movable platform, which comprises a control system and the millimeter wave radar of the embodiment, wherein the control system is in communication connection with the millimeter wave radar, and the millimeter wave radar sends the position information of the detected obstacle to the control system, so that the obstacle avoidance effect of the movable platform is achieved. The movable platform in the embodiment of the present application may be an autonomous vehicle or a vehicle equipped with an Advanced Driver Assistance System (ADAS). The control system on the vehicle may be a computing platform on the vehicle for acquiring data or information from various sensors mounted on the vehicle and making decisions and controls based on the data and information. The millimeter wave radar is a sensor mounted on a vehicle, the number of the sensors can be one or more, and the sensors can be distributed in the front side, the rear side, the left side or the right side of the vehicle in a central or symmetrical mode.
The movable platform of this embodiment may also include unmanned planes, unmanned ships, mobile robots, and the like.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The array antenna, the signal processing method thereof, and the millimeter wave radar provided in the embodiments of the present application are described in detail above, and a specific example is applied in the present application to explain the principle and the embodiments of the present application, and the description of the above embodiments is only used to help understand the method and the core idea of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims (21)

1. The array antenna for the millimeter wave radar work is characterized by comprising a substrate and N arranged on the substrate1First antennas arranged at intervals at equal intervals and N arranged on substrate2The first antenna is one of a receiving antenna and a transmitting antenna, and the second antenna is the other one of the receiving antenna and the transmitting antenna;
N1the first antenna is arranged at N2One side of the second antenna, N1、N2Is a natural number, and N1≥2，N2≧ 2, and the first antenna and the second antenna are substantially parallel, and the distance d between adjacent first antennas1Comprises the following steps: md2D, the spacing d of adjacent second antennas2Comprises the following steps: 2d or 4 d;
wherein ,
Figure FDA0002783675160000011
m is a natural number, and 2 is not less than MN2And λ is the operating wavelength of the array antenna.
2. Array antenna according to claim 1, characterized in that the transmit antenna operates on a time division basis.
3. The array antenna of claim 2, wherein in the time division mode, a plurality of transmitting antennas alternately operate in sequence at preset time intervals, and the array antenna forms an equivalent transmitting antenna and an equivalent receiving antenna;
wherein d is a distance between minimum adjacent receiving antennas in the equivalent receiving antennas in the time division mode.
4. The array antenna of claim 3, wherein the first antenna is a transmit antenna and the second antenna is a receive antenna;
in the time division mode, N1Translating the first antenna except the first antenna adjacent to the second antenna to the position of the first antenna adjacent to the second antenna so as to form an equivalent transmitting antenna;
and ,N2Integrally translating the second antenna by a first distance to obtain N2Root virtual receiving antenna, N2Root said second antenna and N2The virtual receiving antennas form equivalent receiving antennas together;
wherein the first pitch is (N)1-1)*(Md2-d)。
5. The array antenna of claim 4, wherein the first antenna comprises two and the second antenna comprises four.
6. Array antenna according to claim 4 or 5, characterized in that the spacing d of adjacent first antennas1Comprises the following steps:
Figure FDA0002783675160000012
or
Figure FDA0002783675160000013
The distance d between adjacent second antennas2Comprises the following steps: lambda is measured.
7. The array antenna of claim 3, wherein the first antenna is a receive antenna and the second antenna is a transmit antenna;
in the time division mode, N2Translating the second antennas except the second antenna adjacent to the first antenna to the position of the second antenna adjacent to the first antenna so as to form an equivalent transmitting antenna;
and ,N1Integrally translating the first antenna by a first distance size to obtain N1Root virtual receiving antenna, N1Root said first antenna and N1The virtual receiving antennas form equivalent receiving antennas together;
wherein the first pitch is (N)2-1) × 2d, or, alternatively, said first pitch ═ N (N)2-1)*4d。
8. The array antenna of claim 1, wherein the first antenna comprises a plurality of series of subarrays; and/or the second antenna comprises a plurality of series of sub-arrays.
9. A millimeter-wave radar characterized by comprising:
an antenna substrate; and the array antenna is arranged on the antenna substrate, wherein the array antenna comprises N arranged on the antenna substrate1First antennas arranged at intervals at equal intervals and N arranged on antenna substrate2The first antenna is one of a receiving antenna and a transmitting antenna, and the second antenna is the other one of the receiving antenna and the transmitting antenna;
N1the first antenna is arranged at N2One side of the second antenna, N1、N2Is a natural number, and N1≥2，N2≧ 2, and the first antenna and the second antenna are substantially parallel, and the distance d between adjacent first antennas1Comprises the following steps: md2D, the spacing d of adjacent second antennas2Comprises the following steps: 2d or 4 d;
wherein
Figure FDA0002783675160000021
M is a natural number, and M is more than or equal to 2 and less than or equal to N2λ is the operating wavelength of the array antenna;
the transmitting antenna is used for transmitting microwave signals, the receiving antenna is used for receiving echo signals, and the millimeter wave radar can determine position information of the obstacle according to the echo signals.
10. The millimeter-wave radar of claim 9, wherein the transmit antenna operates based on a time division mode.
11. The millimeter wave radar according to claim 10, wherein in the time division mode, a plurality of transmitting antennas alternately operate in sequence at preset time intervals, and the array antennas form an equivalent transmitting antenna and an equivalent receiving antenna, wherein d is a distance between minimum adjacent receiving antennas in the equivalent receiving antennas in the time division mode.
12. The millimeter wave radar of claim 11, wherein the first antenna is a transmit antenna and the second antenna is a receive antenna;
in the time division mode, N1Translating the first antenna except the first antenna adjacent to the second antenna to the position of the first antenna adjacent to the second antenna so as to form an equivalent transmitting antenna;
and ,N2Integrally translating the second antenna by a first distance to obtain N2Root virtual receiving antenna, N2Root said second antenna and N2The virtual receiving antennas form equivalent receiving antennas together;
wherein the first pitch is (N)1-1)*(Md2-d)。
13. The millimeter wave radar of claim 12, wherein the first antenna comprises two and the second antenna comprises four.
14. The millimeter wave radar according to claim 12 or 13, wherein a pitch d of adjacent first antennas1Comprises the following steps:
Figure FDA0002783675160000031
or
Figure FDA0002783675160000032
The distance d between adjacent second antennas2Comprises the following steps: lambda is measured.
15. The millimeter wave radar of claim 11, wherein the first antenna is a receive antenna and the second antenna is a transmit antenna;
in the time division mode, N2The second antennas except the second antenna adjacent to the first antenna in the second antennas are all translated to the position of the second antenna adjacent to the first antenna to form an equivalent transmitting antenna, and N is1Integrally translating the first antenna by a first distance size to obtain N1Root virtual receiving antenna, N1Root said first antenna and N1The virtual receiving antennas form equivalent receiving antennas together;
wherein the first pitch is (N)2-1) × 2d, or, alternatively, said first pitch ═ N (N)2-1)*4d。
16. The millimeter wave radar of claim 9, wherein the first antenna comprises a plurality of series of subarrays; and/or the second antenna comprises a plurality of series of sub-arrays.
17. A movable platform, comprising:
a control system; and
the millimeter wave radar of any one of claims 9 to 16, the control system being communicatively coupled to the millimeter wave radar, the millimeter wave radar transmitting location information of the detected obstacle to the control system.
18. The array antenna signal processing method for millimeter wave radar work is characterized in that the array antenna comprises a plurality of transmitting antennas and a plurality of receiving antennas, the transmitting antennas are arranged on one sides of the receiving antennas and are approximately parallel to the receiving antennas, the transmitting antennas work based on a time division mode, the transmitting antennas work alternately in sequence according to preset time intervals in the time division mode, and the array antennas form equivalent transmitting antennas and equivalent receiving antennas; the method comprises the following steps:
obtaining a complex value of each equivalent receiving antenna;
determining a first antenna vector according to the arrangement sequence of the equivalent receiving antennas and the complex values of the equivalent receiving antennas;
obtaining the distance between adjacent equivalent receiving antennas;
and if the distance between the adjacent equivalent receiving antennas is greater than a preset threshold value, zero padding is carried out between the complex values of the adjacent equivalent receiving antennas in the first antenna vector, and a second antenna vector is obtained.
19. The method of claim 18, wherein the preset threshold is greater than or equal to twice the minimum of the spacings of adjacent equivalent receive antennas.
20. The method of claim 18, further comprising:
and measuring the angle of the object according to the second antenna vector.
21. The method of claim 20, wherein measuring an object angle from the second antenna vector comprises:
processing the second antenna vector using a Fast Fourier Transform (FFT);
and measuring the angle of the object according to the second antenna vector after the FFT.
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