CN113325363A

CN113325363A - Method and device for determining direction of arrival and related equipment

Info

Publication number: CN113325363A
Application number: CN202110210917.4A
Authority: CN
Inventors: 朱砚
Original assignee: Calterah Semiconductor Technology Shanghai Co Ltd
Current assignee: Calterah Semiconductor Technology Shanghai Co Ltd
Priority date: 2020-02-28
Filing date: 2021-02-25
Publication date: 2021-08-31
Also published as: CN113325408A; CN113325414B; CN113325414A; CN113325408B

Abstract

The application discloses a method, a device and related equipment for determining a direction of arrival, which comprises the following steps: acquiring original target data, performing DBF (direct binary frequency) processing on the original target data to obtain target data to be confirmed, and taking any target to be confirmed in the target data to be confirmed as a first target; and then, acquiring the angle value of the first target, obtaining an angle interval to be confirmed by taking the angle value of the first target as a center based on a preset angle threshold, and finally performing at least two-dimensional ML search in the angle interval to be confirmed to confirm the number of the real targets corresponding to the first target. It can be seen that the direction of arrival of one or more real targets can be determined near the angle value of the first target, so that when a plurality of targets in the detection area are close to each other, different directions of arrival corresponding to different targets can be determined, and the accuracy of the number of targets detected by the system can be improved.

Description

Method and device for determining direction of arrival and related equipment

The present application claims priority from the chinese patent application entitled "a method, apparatus and device for determining direction of arrival" filed by the chinese patent office on 28/02/2020, application number 202010131618.7, the entire contents of which are incorporated herein by reference.

Technical Field

The present application relates to the field of target detection technologies, and in particular, to a method and an apparatus for determining a direction of arrival, and a related device.

Background

In an object detection system, a signal (usually, an FMCW signal) transmitted by a transmitting antenna is reflected by an object in a detection area, and then the transmitting signal is received by a receiving antenna, so that a Direction angle of the object relative to the system, which may also be referred to as Direction of Arrival (DOA), can be determined by sampling the reflected signal.

Generally, if a plurality of targets exist in the detectable area of the system, the distances between the targets and the system are substantially the same, and the targets move at substantially the same speed, the targets may be determined according to the directions of arrival corresponding to different targets, that is, different targets are located in different directions of the radar, so that the number of targets detected in the radar detection area may be counted. However, in some practical scenarios, if the multiple targets are close to each other, the radar system may determine only one direction of arrival, and therefore, the multiple targets may be identified as one target based on the one direction of arrival, thereby reducing the accuracy of the radar system in detecting the number of targets.

Disclosure of Invention

In order to solve the above technical problem, embodiments of the present application provide a method, an apparatus, and a related device for determining directions of arrival, so as to accurately identify different directions of arrival corresponding to different targets, so as to improve the accuracy of detecting the number of targets by a radar system.

In a first aspect, an embodiment of the present application provides a method for determining a direction of arrival, where the method includes: acquiring original target data; carrying out Digital Beam Forming (DBF) processing on the original target data to obtain target data to be confirmed; taking any target to be confirmed in the target data to be confirmed as a first target; and performing a Maximum Likelihood (ML) search operation on the first target; wherein the ML search operation includes: obtaining an angle value of the first target; based on a preset angle threshold value, and with the angle value of the first target as a center, obtaining an angle interval to be confirmed; and performing at least two-dimensional ML search in the angle interval to be confirmed to confirm the number of real targets corresponding to the first target.

After the first target is determined, the first target is not directly taken as a finally determined target, that is, a target arrival direction is not determined based on the first target value, but the number of real targets is further determined by ML search in the vicinity of the first target, for example, the number of real targets corresponding to the first target may be multiple, so that when multiple targets in the detection area are close to each other, different arrival directions corresponding to different targets can be determined, that is, the system can identify the multiple targets, thereby avoiding the system from identifying the multiple targets as one target based on only the determined arrival direction as much as possible, and further improving the accuracy of the number of targets detected by the system.

In one possible embodiment, the acquiring raw target data includes: acquiring an echo signal; and performing digital-to-analog conversion and fast Fourier transform on the echo signal to obtain the original target data, wherein the original target data comprises at least one target to be confirmed, distance dimensional data of each target to be confirmed and speed dimensional data of each target to be confirmed.

In this embodiment, the echo signal is subjected to a corresponding signal processing procedure, so that original target data can be obtained, and a real target can be determined based on the original target data.

In a possible implementation, the acquiring raw target data further includes: and after the fast Fourier transform, continuously processing CFAR to obtain the original target data.

In this embodiment, the constant false alarm processing is performed during the process of obtaining the original target data, so that the influence of noise data existing in the original target data on the accuracy of the detection of the final real target can be reduced as much as possible.

In a possible implementation manner, the taking any one of the data of the targets to be confirmed as a first target includes: and taking the target to be confirmed with the maximum DBF synthetic energy in the target data to be confirmed as the first target. The larger the DBF synthesis energy is, the higher the possibility that the real target exists in the target to be confirmed is represented, so that the target detection accuracy can be improved.

In a possible implementation manner, after the ML search operation is performed on the target to be confirmed with the maximum DBF synthesis energy in the target data to be confirmed, whether the ML search operation needs to be performed on the remaining targets to be confirmed in the target data to be confirmed is determined according to a preset stop condition; if the ML search operation needs to be carried out on the remaining targets to be confirmed, taking the target to be confirmed with the largest DBF synthetic energy in the remaining targets to be confirmed as the first target and carrying out the ML search operation based on the current received vector; sequentially circulating until the ML search operation is not required to be performed on the remaining targets to be confirmed in the target data to be confirmed according to the preset stop condition; and determining the current receiving vector according to the receiving vector corresponding to the last ML searching operation.

Therefore, through repeated iterative calculation, each target in the detection area can be accurately detected.

In a possible implementation manner, the preset stop condition is that an energy value corresponding to a receiving vector corresponding to each round of ML search operation is smaller than a preset energy threshold; and/or the number of all the determined real targets is larger than a preset number threshold. Therefore, when the preset stopping condition is not met, the iterative calculation process can be stopped in time, and the efficiency and the accuracy of determining the real target are improved.

In a possible embodiment, said performing an ML search in at least two dimensions in said to-be-confirmed angular interval comprises: and performing two-dimensional ML search in the angle interval to be confirmed.

In a possible implementation manner, if the number of real targets corresponding to the first target is 1, outputting the angle information of the first target as a real target angle signal; and if the number of the real targets corresponding to the first target is more than 1, acquiring the angle information of each real target and replacing the angle information of the first target for outputting. In this way, the angle information of the real target(s) corresponding to each target can be output.

In a possible implementation manner, if the number of real targets corresponding to the first target is greater than 1, power information of each real target is acquired and power information output of the first target is replaced. In this way, while outputting the angle information of the real target, the power information of the real target can also be output to provide the multi-dimensional information of the real target.

In a possible implementation manner, if the number of real targets corresponding to the first target is greater than 1, the speed of each real target corresponding to the same first target is the same, and the distance is the same.

In a possible embodiment, the performing an ML search in at least two dimensions in the angle interval to be confirmed to confirm the number of real targets corresponding to the first target includes: performing at least two-dimensional ML search in the angle interval to be confirmed to obtain at least two target angles; if the at least two target angles are distributed on two sides of the angle of the first target when being arranged in sequence according to the value, the number of the real targets corresponding to the first target is larger than 1.

Therefore, the angle value of the real target corresponding to the first target can be obtained on two sides of the angle value of the first target.

In one possible implementation, the ML search includes a coarse search operation and a fine search operation performed in sequence; wherein the rough search operation is used for determining a possible value of a real target corresponding to the first target through an interval point search preliminary; and the fine searching operation is used for searching point by point within a range around the maximum possible value to determine the final value of the real target corresponding to the first target.

Because only a small number of discrete points are traversed when searching the rough-grained approximate position of the possible value of the real target corresponding to the first target, and only a small number of discrete points are selected at the rough-grained approximate position for accurate positioning, the target detection system can determine the final value of the real target corresponding to the first target by traversing only the small number of discrete points without traversing all the discrete points, thereby reducing the calculation resources consumed by the target detection system for determining the first target discrete points.

In a second aspect, an embodiment of the present application provides a method for determining a direction of arrival, where the method includes: acquiring a plurality of discrete points, wherein the discrete points are obtained at least by performing digital beam forming processing on echo signals, the abscissa of each discrete point represents the direction of arrival, and the ordinate of each discrete point represents an energy value or a power value; determining a first initial direction of arrival of a first target discrete point according to the coordinate values of the plurality of discrete points, wherein the longitudinal coordinate value of the first target discrete point in the plurality of discrete points is the largest; determining a first direction of arrival set according to the first initial direction of arrival, wherein the first direction of arrival set comprises directions of arrival corresponding to a plurality of discrete points, and the absolute value of the difference between each direction of arrival in the first direction of arrival set and the first initial direction of arrival does not exceed a first preset threshold; and determining a plurality of first target directions of arrival in the first direction of arrival set according to the steering vector and the first receiving vector corresponding to each direction of arrival in the first direction of arrival set, wherein the first receiving vector is obtained according to echo signals received by a plurality of receiving channels.

After the first target discrete point with the largest longitudinal coordinate value is determined, the abscissa value of the first target discrete point is not directly used as the finally determined target arrival direction, and a plurality of arrival directions can be further determined near the first target discrete point (i.e. the first arrival direction set), so that when a plurality of targets in the radar detection area are close to each other, different arrival directions corresponding to different targets can be determined, that is, the radar system can recognize the plurality of targets, and thus the radar system can be prevented from recognizing the plurality of targets as one target only based on the determined arrival direction as far as possible, and the accuracy of the number of targets detected by the radar system is improved.

In a possible implementation, the determining, according to the steering vector and the first receiving vector corresponding to each direction of arrival in the first direction of arrival set, a plurality of first target directions of arrival in the first direction of arrival set includes: according to the guiding vector corresponding to each direction of arrival in the first direction of arrival set and the first receiving vector, determining a first direction of arrival and a second direction of arrival from the first direction of arrival set, wherein the guiding vectors corresponding to the first direction of arrival and the second direction of arrival respectively enable the parameter of orthogonal projection of the first receiving vector on a space formed by the first receiving vector to be maximum; calculating a first energy value according to the steering vector corresponding to the first initial direction of arrival and the first receiving vector; calculating a second energy value according to a first direction of arrival, a second direction of arrival, a steering vector corresponding to the first direction of arrival, a steering vector corresponding to the second direction of arrival and the first receiving vector in the first direction of arrival set; and determining the first direction of arrival and the second direction of arrival as a first target direction of arrival according to the magnitude relation between the first energy value and the second energy value. In this way, directions of arrival corresponding to (at least) two real targets can be searched from the set of directions of arrival.

In a possible embodiment, the determining the first direction of arrival and the second direction of arrival as the first target direction of arrival according to the magnitude relationship between the first energy value and the second energy value includes: and when the ratio of the second energy value to the first energy value is not less than a third preset threshold value and/or the difference value of the first energy value and the second energy value is not less than noise energy, determining the first direction of arrival and the second direction of arrival as a first target direction of arrival. Therefore, the arrival directions corresponding to a plurality of real targets can be determined according to the magnitude relation of the two energy values, namely, the number of the real targets is determined to be more than 1.

In one possible embodiment, the method further comprises: and when the ratio of the second energy value to the first energy value is smaller than a third preset threshold value, or the difference value of the first energy value and the second energy value is smaller than noise energy, determining the first initial direction of arrival as a first target direction of arrival. Thus, the number of the real targets can be determined to be 1 according to the magnitude relation of the two energy values.

In one possible embodiment, the method further comprises: determining a second initial direction of arrival of a second target discrete point according to the coordinate values of the plurality of discrete points, wherein the longitudinal coordinate value of the second target discrete point is the largest except the first target discrete point; determining a second direction-of-arrival set according to the second initial direction of arrival, wherein the second direction-of-arrival set comprises directions of arrival corresponding to the plurality of discrete points, and the absolute value of the difference between each direction of arrival in the second direction-of-arrival set and the second initial direction of arrival does not exceed a second preset threshold; and determining one or more second target directions of arrival in the second direction of arrival set according to the steering vector corresponding to each direction of arrival in the second direction of arrival set, the steering vectors of the plurality of first target directions of arrival, and a second receiving vector, wherein the second receiving vector is obtained by calculation according to the first receiving vector and the steering vector corresponding to the first initial direction of arrival. In this way, the number of real targets corresponding thereto can be determined for the next target.

In a possible implementation, the determining a second initial direction of arrival of a second target discrete point according to the coordinate values of the plurality of discrete points includes: and when the energy value corresponding to the first receiving vector is not less than a fourth preset threshold value and/or the number of the determined target directions of arrival is less than a fifth preset threshold value, determining a second initial direction of arrival of a second target discrete point according to the coordinate values of the plurality of discrete points. Therefore, the direction of arrival of the real target with high possibility corresponding to the second target discrete point can be determined, so that the number of the real targets can be further accurately positioned based on the direction of arrival.

In a possible implementation, the determining a first initial direction of arrival of a first target discrete point according to the coordinate values of the plurality of discrete points includes: selecting discrete points at equal intervals from the plurality of discrete points to obtain a first discrete point set; determining a first discrete point in the first set of discrete points having a maximum ordinate value; selecting discrete points from the plurality of discrete points, wherein the interval between the discrete points and the first discrete point does not exceed a preset interval, and obtaining a second discrete point set; and determining the discrete point with the maximum ordinate value in the second discrete point set as the first target discrete point, and determining the first initial direction of arrival according to the abscissa value of the first target discrete point. Therefore, the direction of arrival of the real target with high possibility corresponding to the first target discrete point can be determined, so that the number of the real targets can be further accurately positioned based on the direction of arrival.

In a third aspect, an embodiment of the present application further provides an apparatus for determining a direction of arrival, where the apparatus includes: the acquisition module is used for acquiring original target data; the DBF processing module is used for carrying out Digital Beam Forming (DBF) processing on the original target data to obtain target data to be confirmed; the determining module is used for taking any target to be confirmed in the target data to be confirmed as a first target; and a search module for performing a Maximum Likelihood (ML) search operation on the first target; the searching module is specifically used for acquiring the angle value of the first target; based on a preset angle threshold value, and with the angle value of the first target as a center, obtaining an angle interval to be confirmed; and performing at least two-dimensional ML search in the angle interval to be confirmed to confirm the number of real targets corresponding to the first target.

In a possible embodiment, the acquiring module is specifically configured to acquire an echo signal; and performing digital-to-analog conversion and fast Fourier transform on the echo signal to obtain the original target data: the original target data comprises at least one target to be confirmed, distance dimensional data of each target to be confirmed and speed dimensional data of each target to be confirmed.

In a possible implementation manner, the obtaining module is further configured to continue Constant False Alarm Rate (CFAR) processing after the fast fourier transform to obtain the original target data.

In a possible implementation manner, the determining module is specifically configured to use, as the first target, a target to be confirmed with a largest DBF synthesis energy in the target data to be confirmed.

In a possible embodiment, the apparatus further comprises: the judging module is used for judging whether the ML searching operation needs to be carried out on the targets to be confirmed which are the targets to be confirmed and have the maximum DBF synthetic energy in the target data to be confirmed according to a preset stopping condition after the ML searching operation is carried out on the targets to be confirmed which are the targets to be confirmed and have the maximum DBF synthetic energy in the target data to be confirmed; if the ML search operation needs to be carried out on the remaining targets to be confirmed, taking the target to be confirmed with the largest DBF synthetic energy in the remaining targets to be confirmed as the first target and carrying out the ML search operation based on the current received vector; sequentially circulating until the ML search operation is not required to be performed on the remaining targets to be confirmed in the target data to be confirmed according to the preset stop condition; and determining the current receiving vector according to the receiving vector corresponding to the last ML searching operation.

In a possible implementation manner, the preset stop condition is that an energy value corresponding to a receiving vector corresponding to each round of ML search operation is smaller than a preset energy threshold; and/or the number of all the determined real targets is larger than a preset number threshold.

In a possible embodiment, the search module is specifically configured to perform a two-dimensional ML search in the angle interval to be confirmed.

In a possible embodiment, the apparatus further comprises: the output module is used for outputting the angle information of the first target as a real target angle signal if the number of the real targets corresponding to the first target is 1; and if the number of the real targets corresponding to the first target is more than 1, acquiring the angle information of each real target and replacing the angle information of the first target for outputting.

In a possible implementation manner, the output module is further configured to, if the number of the real targets corresponding to the first target is greater than 1, obtain power information of each real target and output the power information in place of the power information of the first target.

In a possible embodiment, the search module is specifically configured to perform at least two-dimensional ML search in the angle interval to be confirmed to obtain at least two target angles; if the at least two target angles are distributed on two sides of the angle of the first target when being arranged in sequence according to the value, the number of the real targets corresponding to the first target is larger than 1.

In a fourth aspect, an embodiment of the present application further provides an apparatus for determining a direction of arrival, where the apparatus includes: an obtaining module, configured to obtain a plurality of discrete points, where the plurality of discrete points are obtained at least by performing digital beamforming on an echo signal, a horizontal coordinate of the discrete point represents a direction of arrival, and a vertical coordinate of the discrete point represents an energy value or a power value; a first determining module, configured to determine a first initial direction of arrival of a first target discrete point according to coordinate values of the plurality of discrete points, where a ordinate value of the first target discrete point in the plurality of discrete points is the largest; a second determining module, configured to determine a first direction of arrival set according to the first initial direction of arrival, where the first direction of arrival set includes directions of arrival corresponding to a plurality of discrete points, and an absolute value of a difference between each direction of arrival in the first direction of arrival set and the first initial direction of arrival does not exceed a first preset threshold; a third determining module, configured to determine, according to a steering vector and a first receiving vector that correspond to each direction of arrival in the first direction of arrival set, a plurality of first target directions of arrival in the first direction of arrival set, where the first receiving vector is obtained according to echo signals received by a plurality of receiving channels.

In one possible implementation, the third determining module includes: a first determining unit, configured to determine, according to a steering vector corresponding to each direction of arrival in the first direction of arrival set and the first receiving vector, a first direction of arrival and a second direction of arrival from the first direction of arrival set, where steering vectors corresponding to the first direction of arrival and the second direction of arrival respectively maximize a parameter of an orthogonal projection of the first receiving vector on a space formed by the first receiving vector.

The first calculating unit is used for calculating a first energy value according to the guiding vector corresponding to the first initial direction of arrival and the first receiving vector; a second calculating unit, configured to calculate a second energy value according to a first direction of arrival, a second direction of arrival, a steering vector corresponding to the first direction of arrival, a steering vector corresponding to the second direction of arrival, and the first receiving vector in the first direction of arrival set; and the second determining unit is used for determining the first direction of arrival and the second direction of arrival as a first target direction of arrival according to the magnitude relation between the first energy value and the second energy value.

In a possible implementation manner, the second determining unit is specifically configured to determine the first direction of arrival and the second direction of arrival as the first target direction of arrival when a ratio of the second energy value to the first energy value is not less than a third preset threshold and/or a difference between the first energy value and the second energy value is not less than noise energy.

In a possible embodiment, the apparatus further comprises: a fourth determining module, configured to determine the first initial direction of arrival as a first target direction of arrival when a ratio of the second energy value to the first energy value is smaller than a third preset threshold, or a difference between the first energy value and the second energy value is smaller than noise energy.

In a possible embodiment, the apparatus further comprises: a fifth determining module, configured to determine a second initial direction of arrival of a second target discrete point according to coordinate values of the multiple discrete points, where a longitudinal coordinate value of the second target discrete point is the largest except for the first target discrete point; a sixth determining module, configured to determine a second direction-of-arrival set according to the second initial direction of arrival, where the second direction-of-arrival set includes directions of arrival corresponding to the multiple discrete points, and an absolute value of a difference between each direction of arrival in the second direction-of-arrival set and the second initial direction of arrival does not exceed a second preset threshold; a seventh determining module, configured to determine one or more second target directions of arrival in the second direction of arrival set according to the steering vector corresponding to each direction of arrival in the second direction of arrival set, the steering vectors of the plurality of first target directions of arrival, and a second receiving vector, where the second receiving vector is obtained by calculation according to the first receiving vector and the steering vector corresponding to the first initial direction of arrival.

In a possible implementation manner, the fifth determining module is specifically configured to determine, when the energy value corresponding to the first receiving vector is not less than a fourth preset threshold and/or the number of the determined target directions of arrival is less than a fifth preset threshold, a second initial direction of arrival of a second target discrete point according to the coordinate values of the plurality of discrete points.

In one possible implementation, the first determining module includes: the equal interval selecting unit is used for selecting discrete points from the plurality of discrete points at equal intervals to obtain a first discrete point set; a third determining unit, configured to determine a first discrete point in the first discrete point set having a maximum ordinate value; a selecting unit, configured to select, from the multiple discrete points, a discrete point whose interval with the first discrete point does not exceed a preset interval, to obtain a second discrete point set; a fourth determining unit, configured to determine the discrete point with the largest ordinate value in the second set of discrete points as the first target discrete point, and determine the first initial direction of arrival according to the abscissa value of the first target discrete point.

In a fifth aspect, an embodiment of the present application further provides a computer device, where the computer device includes a processor and a memory: the memory is used for storing program codes and transmitting the program codes to the processor; the processor is configured to execute the method for determining a direction of arrival according to any one of the embodiments of the first aspect or the method for determining a direction of arrival according to any one of the embodiments of the second aspect according to instructions in the program code.

In a sixth aspect, an embodiment of the present application further provides an integrated circuit, including: the receiving end is used for receiving echo signals; the digital signal processing module is used for carrying out digital signal processing on the echo signal so as to realize target detection; the digital function module is further configured to determine angle information of each target by using the method for determining a direction of arrival according to any one of the embodiments of the first aspect or the second aspect when the target detection is implemented.

In one possible implementation, the integrated circuit is a millimeter wave radar chip.

In a seventh aspect, an embodiment of the present application further provides a radio device, including: a carrier; an integrated circuit as claimed in any one of the preceding sixth aspects, disposed on a carrier; an antenna disposed on the carrier or on which a device AiP structure is disposed integral with the integrated circuit; the integrated circuit is connected with the antenna and used for transmitting and receiving radio signals.

In an eighth aspect, an embodiment of the present application further provides an apparatus, including: an apparatus body; and a radio device as set forth in the seventh aspect as set forth above provided on the apparatus body; wherein the radio device is used for object detection and/or communication.

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 described in the present application, and other drawings can be obtained by those skilled in the art according to the drawings.

FIG. 1 is a schematic view of an angle-power curve obtained based on a plurality of discrete points;

FIG. 2 is a schematic flow chart illustrating a method for determining a direction of arrival according to an embodiment of the present disclosure;

FIG. 3 is a schematic flow chart illustrating another method for determining a direction of arrival according to an embodiment of the present application;

FIG. 4 is a schematic structural diagram of an apparatus for determining a direction of arrival according to an embodiment of the present application;

FIG. 5 is a schematic structural diagram of another apparatus for determining a direction of arrival according to an embodiment of the present application;

fig. 6 is a schematic hardware structure diagram of an apparatus in an embodiment of the present application.

Detailed Description

When a plurality of targets exist in a detectable area of a radar system, if the plurality of targets are close to each other, move at substantially the same speed, and have substantially the same distance from the radar, it may be difficult to effectively distinguish the plurality of targets using directions of arrival, that is, the radar system may recognize the plurality of targets as one target and the plurality of targets correspond to the same measured direction of arrival.

In a specific implementation, for echo signals reflected back by the multiple targets, a plurality of discrete points can be obtained through digital beam forming processing, and the discrete points can be regarded as being located on a curve. For example, as shown in fig. 1, the resulting plurality of discrete points may be considered to lie on an angle-power curve on the power spectrum. In general, a peak of the curve in which each peak value exceeds a preset value may correspond to a target, and different peak values may correspond to different targets (only one peak is shown in fig. 1), and an angle corresponding to each peak value of the curve (i.e., an angle corresponding to a discrete point having the maximum power) may be determined as a direction of arrival of the corresponding target detected by the radar system.

However, when the two targets are close and keep the same motion state, the actual directions of arrival corresponding to the two targets may differ slightly, so that the radar system may determine only one direction of arrival (the angle value corresponding to the discrete point with the largest ordinate value), that is, the peaks corresponding to the two targets are aggregated into one peak, as shown in fig. 1. This allows the radar system to identify two targets as one target based on the one direction of arrival, thereby reducing the accuracy with which the radar system detects the number of targets.

Based on this, the embodiment of the application provides a method for determining the direction of arrival, which aims to identify different directions of arrival corresponding to different targets as accurately as possible, so as to improve the accuracy of the radar system in detecting the number of the targets. In specific implementation, original target data is obtained, where the original target data may be, for example, echo signals reflected back by a plurality of targets, and then Digital Beam Forming (DBF) processing is performed on the original target data to obtain target data to be confirmed, so that any target to be confirmed in the target data to be confirmed can be used as a first target, and Maximum Likelihood (ML) search operation is performed on the first target, specifically, an angle value of the first target is obtained first, and an angle of the first target is used as a center based on a preset angle threshold, so as to obtain an angle interval to be confirmed, and thus at least two-dimensional ML search can be performed in the angle interval to be confirmed to confirm the number of real targets corresponding to the first target.

It can be seen that after the first target is determined, the first target is not directly taken as a finally determined target, that is, a target arrival direction is not determined based on the first target value, but the number of real targets is further determined by ML search near the first target, for example, the number of real targets corresponding to the first target may be multiple, so that when multiple targets in the detection area are close to each other, different arrival directions corresponding to the multiple targets can be determined for the different targets, that is, the system can identify the multiple targets, thereby avoiding the system from identifying the multiple targets as one target based on only the determined arrival direction as far as possible, and further improving the accuracy of the number of targets detected by the system.

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, various non-limiting embodiments accompanying the present application examples are described below with reference to the accompanying drawings. It is to be understood that the embodiments described are only a few embodiments of the present application and not all 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.

Referring to fig. 2, fig. 2 is a schematic flowchart illustrating a method for determining a direction of arrival in an embodiment of the present application, where the method may be applied to a target detection system, specifically, a radar system, and the method may specifically include:

s201: original target data is acquired.

In practical application, when a target detection system (such as a radar system) detects a target in a detectable region of the target detection system, a transmitting antenna may transmit a Chirp signal, and an echo signal formed by the Chirp signal after being reflected by the target may be received by a receiving antenna.

For the echo signal received by the receiving antenna, the target detection system can perform digital-to-analog conversion and fast fourier transform on the echo signal to obtain original target data, wherein the original target data comprises at least one target to be confirmed, distance dimension data of each target to be confirmed and speed dimension data of each target to be confirmed.

In another embodiment of acquiring original target data, after performing digital-to-analog conversion and fast fourier transform on an echo signal, the target detection system may further perform Constant False Alarm-Alarm Rate (CFRA) processing on the obtained data, and use the data obtained after the CFRA processing as the original target data.

S202: and carrying out DBF processing on the acquired original target data to obtain target data to be confirmed.

After obtaining the original target data, the target detection system may perform Digital Beam Forming (DBF) on the original target data to obtain target data to be confirmed and obtain a plurality of discrete points. For example, the target data to be confirmed may include a plurality of discrete points, and an abscissa of each discrete point may represent a direction of arrival, and an ordinate of each discrete point may represent an energy value, a power value, or the like, so that based on the plurality of discrete points, an angle-energy spectrum or an angle-power spectrum formed by the plurality of discrete points may be obtained.

As an example, when the ordinate of the discrete point represents the energy spectrum, in the process of performing the digital beam forming operation, the ordinate of each discrete point may be calculated based on the formula (1), and the abscissa of each discrete point is the direction of arrival of different values, so that different discrete points may be obtained based on the values of different directions of arrival.

P_bfm(θ，y)＝||v^H(θ)y||² (1)

Wherein, P_bfm(theta, y) is the resultant energy in the direction of arrival theta, v^HAnd (theta) is a conjugate transpose of a steering vector corresponding to the arrival direction angle theta, y represents a receiving vector, values of components of the receiving vector are signal output of each receiving channel (corresponding to each receiving antenna) of the radar system, and | | is a norm.

S203: and taking any target to be confirmed in the target data to be confirmed as a first target.

It should be noted that the data of the target to be confirmed may include one or more targets to be confirmed, and the number of the real targets corresponding to each target to be confirmed may be one or more (for example, a plurality of targets with similar distances and identical or similar motion states). It is understood that when the speed and the distance at which a plurality of targets exist within the target detection area are the same, there may be only one target to be confirmed determined by the DBF processing, but the number of real targets may be plural.

In this embodiment, the targets to be confirmed may be detected one by one to determine the number of real targets actually corresponding to each target to be confirmed, so that even if a plurality of targets having similar distances and identical or similar motion states exist in the practical application, the target detection system may accurately detect the direction of arrival corresponding to each target, that is, the number of targets.

Based on this, the target detection system may select any target to be confirmed from the data to be confirmed as the first target, for example, the target to be confirmed with the largest DBF synthesis energy in the data to be confirmed may be used as the first target, and the ML search is performed on the first target to determine the number of real targets corresponding to the first target, specifically, the following steps may be performed on the first target:

s204: an angle value of the first target is obtained.

S205: and based on a preset angle threshold value, taking the angle of the first target as a center to obtain an angle interval to be confirmed.

S206: and performing at least two-dimensional ML search in the angle interval to be confirmed to confirm the number of the real targets corresponding to the first target.

It should be understood that, even if the first target corresponds to a plurality of real targets, the angles of the plurality of real targets do not greatly deviate from the angle value of the first target, that is, the arrival direction of each real target is located in the vicinity of the angle value, and therefore, the target detection system can acquire the angle value of the first target and perform an accurate search within a certain range in the vicinity of the angle value of the first target.

In specific implementation, the target detection system may obtain an angle value of the first target, and generate an angle interval to be confirmed based on a preset angle threshold value and with the angle value of the first target as a center. And the deviation of the angle value between each angle value in the angle interval to be confirmed and the angle value of the first target does not exceed the preset angle threshold.

For example, assume the first target has an angle value of θ_i(i.e. the direction of arrival corresponding to the ith discrete point), if the preset threshold is δ θ, the calculated angle interval to be confirmed may be [ θ [ [ theta ]_i-δθ，θ_i+δθ]The angle interval to be confirmed may include θ_i-k、θ_i-k+1、...、θ_i-1、θ_i、θ_i+1、...、θ_i+k-1、θ_i+kAnd a plurality of directions of arrival. Wherein, theta_i-kNot less than theta_i-δθ，θ_i+kNot greater than theta_i+δθ。

Then, the target detection system may perform at least two-dimensional ML search from the angle interval to be confirmed to confirm the number of real targets corresponding to the first target. As an example, when the target detection system performs at least two-dimensional ML search in the angle interval to be confirmed to obtain at least two target angles, and the at least two target angles are distributed on two sides of the angle of the first target when they are arranged in sequence according to the value, this indicates that the number of real targets corresponding to the first target is greater than 1, and the directions of arrival corresponding to each real target are at least two target angles obtained by ML search, respectively.

In a possible implementation manner, when the target detection system performs the ML search in the angle interval to be confirmed, the rough search operation may be performed first, and then the fine search operation may be performed. The rough searching operation refers to preliminarily determining a possible value of a real target corresponding to the first target through interval point searching in the angle interval to be confirmed, and then determining a final value of the real target corresponding to the first target through point-by-point searching in a range near the maximum possible value by utilizing the fine searching operation. Because only a small number of discrete points are traversed when searching the rough-grained approximate position of the possible value of the real target corresponding to the first target, and only a small number of discrete points are selected at the rough-grained approximate position for accurate positioning, the target detection system can determine the final value of the real target corresponding to the first target by traversing only the small number of discrete points without traversing all the discrete points, thereby reducing the calculation resources consumed by the target detection system for determining the first target discrete points.

When determining the number of the real targets corresponding to the first target, the target detection system may specifically perform corresponding calculation according to the steering vector and the receiving vector corresponding to each direction of arrival included in the angle interval to be confirmed, so that the number of the real targets corresponding to the first target may be determined according to the result obtained by the calculation. The receiving vector may be obtained according to echo signals received by a plurality of receiving channels, and specifically, each component of the receiving vector is a signal output of each receiving channel (corresponding to each receiving antenna) of the target detection system.

For the sake of understanding, the following description takes the example of determining two directions of arrival (i.e. the number of real targets is 2) from the angle interval to be confirmed, and the specific implementation of determining three or more targets from the angle interval to be confirmed is similar to the above description.

In a specific implementation, two directions of arrival, hereinafter referred to as a first direction of arrival and a second direction of arrival, may be determined from the angle interval to be confirmed according to the guiding vector and the receiving vector corresponding to each direction of arrival in the angle interval to be confirmed, where the determined guiding vectors corresponding to the first direction of arrival and the second direction of arrival respectively enable a parameter of an orthogonal projection of the receiving vector on a space formed by the receiving vector to be the largest, and may equivalently be that a residual energy after the orthogonal projection of the receiving vector on the space formed by the receiving vector is the smallest. For example, the first direction of arrival and the second direction of arrival may be determined by equations (2), (3):

wherein the content of the first and second substances,

a first direction of arrival is characterized,

characterizing a second direction of arrival, θ₁And theta₂Characterizing any two directions of arrival, v (θ), in a first set of directions of arrival₁) Characterizing direction of arrival θ₁Corresponding guide vector, v (θ)₂) Characterizing direction of arrival θ₂The corresponding steering vector is set to the direction of the steering vector,

the representation includes a steering vector v (θ)₁) And v (θ)₂) The pseudo-inverse of the matrix of steering vectors of (c),

characterizing a steering vector v (θ)₁) And v (θ)₂) Such that the received vector r is a parameter of the orthogonal projection of the space formed by the received vector r.

Based on equation (2), it can also be equivalently transformed into equation (4):

wherein the content of the first and second substances,

characterizing a steering vector v (θ)₁) And v (θ)₂) Such that the residual energy of the received vector r after the orthogonal projection onto the space comprised by the received vector r.

Further, in the case of performing the calculation based on hardware, in order to reduce the calculation resource consumption, the first direction of arrival and the second direction of arrival may be calculated by the following equations (5), (6), and (7):

wherein the content of the first and second substances,

characterizing a set of determined steering vectors usable for indicating a target direction of arrival of a target, the target direction of arrival being comprised by a first peak when calculating the target direction of arrival

Can be an empty set, alpha token set

Any of the steering vectors.

Also, in some embodiments, to further simplify the negative complexity of the calculation process, one may also useMay omit those in the above formula (6)

And in equation (7)

That is, the above equation (6) and equation (7) can be simplified as follows:

after the first direction of arrival and the second direction of arrival are determined from the angle interval to be confirmed, the first energy value can be calculated according to the guide vector corresponding to the first direction of arrival and the receiving vector, and the second energy value can be calculated according to the first direction of arrival, the second direction of arrival, the guide vector corresponding to the first direction of arrival, the guide vector corresponding to the second direction of arrival and the receiving vector in the angle interval to be confirmed.

In one example, the first energy value P may be calculated by equation (10)_res1：

The second energy value P may be calculated by equation (11)_res2：

After calculating the first energy value P_res1And a second energy value P_res2Then, whether the first direction of arrival and the second direction of arrival are determined according to the magnitude relation between the first energy value and the second energy valueThe direction is determined as the direction of arrival corresponding to the real target (at this time, the directions of arrival corresponding to the two real targets are determined near the first initial direction of arrival, respectively

And

)。

in a further specific embodiment, the direction of arrival corresponding to the plurality of real targets may be determined according to the difference and/or the ratio between the first energy value and the second energy value. For example, when the ratio of the second energy value to the first energy value is not less than the third preset threshold, and/or the difference between the first energy value and the second energy value is not less than the noise energy, both the first direction of arrival and the second direction of arrival are determined as the direction of arrival corresponding to the real target. For example, when α P_res1≥P_res2Then, it can be determined that

And

as the direction of arrival corresponding to the real target, wherein α is a positive number smaller than 1; or, when P is_res1-P_res2≥βP_noiseThen, it can be determined that

And

direction of arrival as a true target, where P_noiseThe energy is noise energy which can be obtained by performing noise estimation on an echo signal, and beta is a coefficient not less than 1; of course, P may be the same as P_res1And P_res2Satisfy alpha P at the same time_res1≥P_res2And P_res1-P_res2≥βP_noiseThen it is determined that

And

as the direction of arrival corresponding to the real target.

Further, when the ratio of the second energy value to the first energy value is smaller than a third predetermined threshold (e.g., α P)_res1＜P_res2) Or the difference between the first energy value and the second energy value is smaller than the noise energy (such as P)_res1-P_res2＜βP_noise) In this case, the first direction of arrival may be determined as the direction of arrival corresponding to the real target, and at this time, the number of the real targets is 1.

Further, when the arrival direction corresponding to the real target is output, if it is determined that the number of the real targets corresponding to the first target is 1, the target detection system may output the angle information of the first target as a real target angle signal, and if the number of the real targets corresponding to the first target is greater than 1, the target detection system acquires the angle information of each real target and replaces the angle information of the first target to output.

As an example, if the number of real targets corresponding to the first target is greater than 1, the target detection system may further obtain power information of the real target and replace the power information of the first target for outputting, in addition to outputting angle information of the real target.

It should be noted that, the foregoing is an example of determining the directions of arrival corresponding to two real targets from the angle interval to be confirmed, and the process of determining the directions of arrival corresponding to three or more real targets from the angle interval to be confirmed may be calculated by using a similar principle to the foregoing, which is not described herein again. In practical application, in the vicinity of the first initial direction of arrival, the search for directions of arrival in different dimensions can be attempted, that is, assuming that there are two directions of arrival corresponding to the real target in the vicinity of the angle value of the first target, two values can be searched according to the above process and judged; then, assuming that three directions of arrival corresponding to the real targets exist near the angle value of the first target, three values can be determined according to a calculation principle similar to the above process, and corresponding determination is performed, and so on.

The above description is made for determining the number of real targets corresponding to each target to be confirmed, and in practical applications, a phenomenon that a plurality of targets in different directions are gathered may exist in the target detection region, for example, while at least two targets are close to each other in a direction where the direction of arrival is approximately 45 °, at least two targets may also be close to each other in a direction where the direction of arrival is approximately-30 °, so that when the radar system obtains an angle-power spectrum similar to that shown in fig. 1, a plurality of peaks may exist, and a plurality of targets may be gathered in the direction of arrival corresponding to each peak. Therefore, in this embodiment, one or more directions of arrival corresponding to each peak may be determined by an iterative calculation.

For ease of understanding, the second iterative calculation is exemplified below.

When executing the second iterative computation process, after performing ML search operation on the target to be confirmed with the maximum DBF synthesis energy in the target data to be confirmed, judging whether ML search operation needs to be performed on the remaining target to be confirmed in the target data to be confirmed according to a preset stop condition; if the ML search operation needs to be continuously carried out on the remaining targets to be confirmed, the target to be confirmed with the maximum DBF synthetic energy in the remaining targets to be confirmed is used as the first target again, and the ML search operation is carried out based on the current received vector; and determining the current receiving vector according to the receiving vector corresponding to the last ML searching operation. For example, the current receiving vector may be calculated according to the receiving vector in the last iterative calculation and the steering vector corresponding to the angle value of the first target.

Taking the example of searching for two directions of arrival (corresponding to two targets) from the angle interval to be confirmed corresponding to the first target in the second iterative calculation process, the two directions of arrival can be determined from the angle interval to be confirmed by using the formula (2)

And

the

And

the respective corresponding steering vectors maximize, equivalently, the parameters of the orthogonal projection of the current received vector onto the space formed by the current received vector

And

the respective corresponding steering vectors minimize the residual energy after the orthogonal projection of the currently received vector onto the space formed by the currently received vector.

It should be noted that the determination is made by using the formula (2)

And

in the formula (2)

The method is a conjugate transpose of a steering vector matrix formed by steering vectors corresponding to any two different directions of arrival in an angle interval to be confirmed in the current iterative computation process and the steering vector corresponding to the direction of arrival of the real target determined in the last iterative computation, namely after the direction of arrival corresponding to the real target is determined in the last iterative computation, the steering vector corresponding to the direction of arrival corresponding to the real target can be added to a set

And in formula (2)

The current receiving vector may be calculated according to equation (12):

where r' characterizes the current received vector,

characterizing the pseudo-inverse of a matrix V formed by steering vectors corresponding to the directions of arrival of the targets, which may be by V when the column is full rank

Is calculated to obtain V^HThe conjugate transpose of the characterization matrix V.

Further, the current receiving vector may also be calculated according to formula (13):

determining two directions of arrival from an angle interval to be determined

And

then, two energy values corresponding to the two directions of arrival can be calculated by using equations (10) and (11), and the direction of arrival indicating the real target is determined based on the relationship between the two energy values.

And when subsequent iterative computation exists, computing still according to the process, and sequentially circulating until the ML search operation is not required to be performed on the remaining targets to be confirmed in the target data to be confirmed according to the preset stop condition.

As some examples, the preset stop condition may be, for example, whether an energy value corresponding to the currently received vector in each round of iterative computation is smaller than a preset energy threshold, if not, the current iterative computation may be continued, and if so, the iterative computation process may be stopped. The preset energy threshold may be, for example, a preset fixed value, or may be calculated according to a noise energy value obtained by noise estimation, for example, may be a preset multiple of the noise energy.

Or, the preset stop condition may be whether the number of all currently determined real targets (or the number of directions of arrival of the real targets) is smaller than a preset number threshold, if so, the current iterative computation may be continued, and if not, the iterative computation process may be stopped. The preset number threshold may be a preset fixed value, or may be a value smaller than the number of components of the received vector (the number of receiving channels of the echo signal) in the first iterative computation, for example, the number of components is reduced by 1, or may be an estimated value in the first iterative computation, for example, it may be predicted that K peaks exist in the first iterative computation, and then the preset number threshold may be K.

In practical applications, the iteration stop condition may be one or more combinations of the above conditions, and when the iteration stop condition is specifically implemented, the iteration stop condition may be determined according to requirements of practical applications, and is not limited herein.

In this embodiment, after the first target is determined, the first target is not directly used as a finally determined target, that is, a target direction of arrival is not determined based on the first target value, but the number of real targets is further determined by ML search near the first target, for example, the number of real targets corresponding to the first target may be multiple, so that when multiple targets in the detection area are close to each other, different directions of arrival corresponding to different targets can be determined, that is, the system can recognize the multiple targets, thereby avoiding as much as possible that the system recognizes the multiple targets as one target based on only the determined direction of arrival, and further improving the accuracy of the number of targets detected by the system.

In addition, the embodiment of the application also provides another method for determining the direction of arrival. Referring to fig. 3, fig. 3 is a flowchart illustrating a method for determining a direction of arrival in an embodiment of the present application, where the method may be applied to an object detection system, such as a radar system, and the method may specifically include:

s301: obtaining a plurality of discrete points, the plurality of discrete points being obtained at least by performing digital beamforming processing on the echo signal, wherein an abscissa of each discrete point represents a direction of arrival and an ordinate of the discrete point represents an energy value or a power value.

In practical application, when the radar system detects a target in a detectable area of the radar system, the transmitting antenna can send a Chirp signal, and an echo signal formed by the Chirp signal after the Chirp signal is reflected by the target can be received by the receiving antenna. The radar system may then perform digital beamforming on the received echo signals to obtain a plurality of discrete points. The obtained abscissa of the plurality of discrete points may represent the direction of arrival, and the ordinate of the discrete points may represent the energy value or the power value, so that based on the plurality of discrete points, the angle-energy spectrum or the angle-power spectrum formed by the plurality of discrete points may be obtained.

As an example, when the ordinate of the discrete point represents the energy spectrum, the ordinate of each discrete point may be calculated based on the formula (1), and the abscissa of each discrete point is a direction of arrival of different values, so that different discrete points may be obtained based on the values of different directions of arrival.

P_bfm(θ，y)＝||v^H(θ)y||² (14)

Wherein, P_bfm(theta, y) is the resultant energy in the direction of arrival theta, v^H(theta) is the conjugate transpose of the steering vector corresponding to the direction of arrival angle theta, y represents the received vector whose components have values for the respective receive channels (corresponding to the respective receive antennas) of the radar systemAnd (5) outputting the signal, wherein | | is a norm.

S302: and determining a first initial direction of arrival of the first target discrete point according to the coordinate values of the plurality of discrete points, wherein the ordinate value of the first target discrete point in the plurality of discrete points is the maximum.

In this embodiment, after obtaining the plurality of discrete points, the plurality of discrete points may be traversed to determine a discrete point having a maximum ordinate (hereinafter referred to as a first target discrete point), and further determine an abscissa of the first target discrete point, where the abscissa is the first initial direction of arrival in step S302.

In some possible embodiments, when determining the first target discrete point, the determination may be performed by performing a coarse-grained search and then performing a fine-grained search. Specifically, discrete points may be selected from a plurality of discrete points at equal intervals, for example, discrete points may be selected every two points, and thus a set (hereinafter referred to as a first set of discrete points) of the plurality of selected discrete points may be obtained. Then, each discrete point in the first set of discrete points may be traversed to determine the discrete point having the largest ordinate value (hereinafter referred to as the first discrete point). It is understood that the first discrete point is only the discrete point having the largest ordinate value in the first set of discrete points, but the ordinate value may not be the largest among all the discrete points, and in practical applications, the first target discrete point having the largest ordinate value may be located near the first discrete point (of course, the first discrete point may also be the first discrete point), so that a plurality of discrete points closer to the first discrete point may be selected from all the discrete points, and specifically, a discrete point having a distance from the first discrete point not exceeding a preset distance (for example, the preset distance is 3, etc.) may be selected, and these selected discrete points may constitute the second set of discrete points, and the first target discrete point is one of the second set of discrete points. Based on this, all points in the second discrete point set can be traversed, and the first target discrete point with the maximum ordinate value is determined, so that the first initial direction of arrival can be determined according to the abscissa value of the first target discrete point.

Because only a small number of discrete points are traversed when the rough-grained approximate position of the first target discrete point is located, and only a small number of discrete points are selected at the rough-grained approximate position for accurate location, the radar system can determine the first target discrete point from all the discrete points by only traversing the small number of discrete points, and does not need to perform traversal calculation on all the discrete points, so that the calculation resources consumed by the radar system for determining the first target discrete point can be reduced.

It will be appreciated that the determined first initial direction of arrival is only indicative of the orientation of a target relative to the radar, and thus the radar system identifies a target based on that direction of arrival. However, in practical applications, when a plurality of targets are close to each other, the radar system may not accurately identify the plurality of targets and may incorrectly identify the plurality of targets as one target due to the measurement accuracy limitation of the radar system. Based on this, after the first initial direction of arrival is determined in the present embodiment, it may be further determined whether there are multiple directions of arrival corresponding to multiple targets (hereinafter referred to as first target directions of arrival for convenience of description) within a certain range around the first initial direction of arrival. In a specific implementation, the following step S203 may be performed first to determine all possible value ranges of the direction of arrival near the first initial direction of arrival.

S203: and determining a first direction of arrival set according to the first initial direction of arrival, wherein the first direction of arrival set comprises the directions of arrival corresponding to the plurality of discrete points, and the absolute value of the difference between each direction of arrival in the first direction of arrival set and the first initial direction of arrival does not exceed a first preset threshold.

Specifically, a direction-of-arrival interval that is not more than a first preset threshold from the first initial direction of arrival and the first preset threshold may be calculated, and then, a plurality of directions of arrival in the direction-of-arrival interval may be determined from directions of arrival corresponding to discrete points near the first target discrete point, and a set (hereinafter, referred to as a first direction-of-arrival set) may be formed from the determined directions of arrival. Accordingly, the set between each direction of arrival in the first set of directions of arrival and the first initial direction of arrival does not exceed the first preset threshold.

For example, assume that the first initial direction of arrival is θ_i(i.e., the direction of arrival corresponding to the ith discrete point), if the first predetermined threshold is δ θ, the calculated direction of arrival interval may be [ θ [ [ theta ]_i-δθ，θ_i+δθ]So that the direction of arrival at a discrete point near the first target discrete point can be determined to be [ theta ]_i-δθ，θ_i+δθ]Multiple directions of arrival theta_i-k、θ_i-k+1、...、θ_i-1、θ_i、θ_i+1、...、θ_i+k-1、θ_i+kAnd a first set of directions of arrival is formed from the plurality of directions. Wherein, theta_i-kNot less than theta_i-δθ，θ_i+kNot greater than theta_i+δθ。

S204: and determining a plurality of first target directions of arrival in the first direction of arrival set according to the steering vector corresponding to each direction of arrival in the first direction of arrival set and a first receiving vector, wherein the first receiving vector is obtained according to echo signals received by a plurality of receiving channels.

After obtaining a first direction of arrival set including a plurality of directions of arrival, it may be further determined whether a plurality of directions of arrival corresponding to a plurality of targets (hereinafter, referred to as first target directions of arrival) exist in the first direction of arrival set. In a specific implementation, corresponding calculation may be performed according to the steering vector and the first receiving vector corresponding to each direction of arrival in the first direction of arrival set, so that whether a plurality of first target directions of arrival are included in the first direction of arrival set may be determined according to a result obtained by the calculation. The first receiving vector may be obtained according to echo signals received by a plurality of receiving channels, and specifically, each component of the first receiving vector is a signal output of each receiving channel (corresponding to each receiving antenna) of the radar system.

For ease of understanding, the following description is given by way of example to determine two directions of arrival (corresponding to two targets) from the first set of directions of arrival, and embodiments in which three or more directions of arrival are determined from the first set of directions of arrival are similar. In a specific implementation, a first direction of arrival and a second direction of arrival may be determined from the first direction of arrival set according to the steering vector and the first receiving vector corresponding to each direction of arrival in the first direction of arrival set, where the determined steering vectors corresponding to the first direction of arrival and the second direction of arrival respectively enable a parameter of an orthogonal projection of the first receiving vector on a space formed by the first receiving vector to be maximum, and may be equivalent to that a residual energy after the orthogonal projection of the first receiving vector on the space formed by the first receiving vector is minimum. For example, the first direction of arrival and the second direction of arrival may be determined by equations (15), (16):

wherein the content of the first and second substances,

a first direction of arrival is characterized,

characterizing a steering vector v (θ)₁) And v (θ)₂) Such that the first received vector r is a parameter of the orthogonal projection over the space formed by the first received vector r.

Based on equation (15), it can also be equivalently transformed into equation (17):

wherein the content of the first and second substances,

characterizing a steering vector v (θ)₁) And v (θ 2)₎Such that the first received vector r is the residual energy after the orthogonal projection onto the space comprised by the first received vector r.

Further, in order to reduce the consumption of computing resources when performing the calculation based on hardware, the first direction of arrival and the second direction of arrival may be calculated by the following equations (18), (19), and (20):

wherein the content of the first and second substances,

Can be an empty set, alpha token set

Any of the steering vectors.

Moreover, in some embodiments, in order to further simplify the complexity of the calculation process, the formula (19) may be omitted

And in the formula (20)

That is, the above equations (19) and (20) can be simplified as follows:

after the first direction of arrival and the second direction of arrival are determined from the first direction of arrival set, a first energy value may be calculated according to the steering vector corresponding to the first initial direction of arrival and the first receiving vector, and a second energy value may be calculated according to the first direction of arrival, the second direction of arrival, the steering vector corresponding to the first direction of arrival, the steering vector corresponding to the second direction of arrival, and the first receiving vector in the first direction of arrival set.

In one example, the first energy value P may be calculated by equation (23)_res1：

The second energy value P may be calculated by equation (11)_res2：

After calculating the first energy value P_res1And a second energy value P_res2Then, it is determined whether the first direction of arrival and the second direction of arrival are determined as the first target direction of arrival (in this case, two first target directions of arrival are determined near the first initial direction of arrival, respectively)

And

)。

in a further specific embodiment, the multiple first target directions of arrival may be determined according to the difference and/or ratio of the first energy value and the second energy value. For example, when the ratio of the second energy value to the first energy value is not less than the third preset threshold, and/or the difference between the first energy value and the second energy value is not less than the noise energy, both the first direction of arrival and the second direction of arrival are determined as the first target direction of arrival. For example, when α Pres1 ≧ Pres2, it can be determined that

And

as a first target direction of arrival, where α is a positive number less than 1; or, when P is_res1-P_res2≥βP_noiseThen, it can be determined that

And

as a first target direction of arrival, wherein P_noiseFor noise energy, canThe noise estimation is carried out on the echo signal, and beta is a coefficient not less than 1; of course, P may be the same as P_res1And P_res2Satisfy alpha P at the same time_res1≥P_res2And P_res1-P_res2≥βP_noiseThen it is determined that

And

as a first target direction of arrival.

Further, when the ratio of the second energy value to the first energy value is smaller than a third predetermined threshold (e.g., α P)_res1＜P_res2) Or the difference between the first energy value and the second energy value is smaller than the noise energy (such as P)_res1-P_res2＜βP_noise) The first initial direction of arrival may be determined as a first target direction of arrival, which is a value.

It should be noted that, the above is exemplified by determining two first target directions of arrival from the first initial direction of arrival set, and the process of determining three or more first target directions of arrival from the first initial direction of arrival set may be calculated by using a similar principle to the above, which is not described herein again. In practical application, in the vicinity of the first initial direction of arrival, the search for directions of arrival in different dimensions may be attempted, that is, assuming that there are two directions of arrival corresponding to the two targets in the vicinity of the first initial direction of arrival, two values may be searched according to the above process and determined; then, assuming that the directions of arrival corresponding to the three targets exist near the first initial direction of arrival, three values may be determined according to a calculation principle similar to the above process, and corresponding determination may be performed, and so on.

It can be understood that in practical applications, there may be a plurality of targets in different directions gathered in the radar detection area, for example, while there may be at least two targets at a short distance in a direction of about 45 ° of the direction of arrival, there may also be at least two targets at a short distance in a direction of about-30 ° of the direction of arrival, so that when the radar system obtains an angle-power spectrum similar to that shown in fig. 1, there may be a plurality of peaks, and each peak may have a plurality of targets gathered in the direction of arrival corresponding to the peak. Therefore, in this embodiment, one or more directions of arrival corresponding to each peak may be determined by an iterative calculation.

First, after determining a plurality of first target directions of arrival based on a first target discrete point, a second target discrete point of the plurality of discrete points may be further determined, wherein the second target discrete point has a maximum ordinate value except for the first target discrete point among all the discrete points. Then, the abscissa value of the second target discrete point may be taken as the second initial direction of arrival. The process of determining the second target discrete point from the plurality of discrete points is similar to the process of determining the first target discrete point, and the specific implementation process may refer to the description of the relevant parts of the foregoing process, which is not described herein again.

Then, a direction-of-arrival section that is not more than a second preset threshold value from the second initial direction-of-arrival and the second preset threshold value may be calculated, and a plurality of directions of arrival in the direction-of-arrival section may be specified from among the directions of arrival corresponding to the discrete points near the second target discrete point, and a set (hereinafter, referred to as a second direction-of-arrival set) may be formed from the specified directions of arrival. Accordingly, the set between each direction of arrival in the second set of directions of arrival and the second initial direction of arrival does not exceed the second preset threshold.

One or more target directions of arrival (hereinafter referred to as second target directions of arrival) may then be determined from the second set of directions of arrival. Specifically, the corresponding calculation may be performed according to the steering vector corresponding to each direction of arrival in the second direction of arrival set, the steering vectors corresponding to the plurality of first target directions of arrival, and the second receiving vector, so that it may be determined whether the second direction of arrival set includes the plurality of first target directions of arrival or only includes one first target direction of arrival according to the result obtained by the calculation. The second receiving vector may be calculated according to the first receiving vector and the steering vector corresponding to the first initial direction of arrival.

Taking the example of searching for two directions of arrival (corresponding to two targets) from a first set of directions of arrival, two directions of arrival can be determined from a second set of directions of arrival using equation (15)

And

the

And

the respective corresponding steering vectors maximize the parameters of the orthogonal projection of the second received vector onto the space formed by the second received vector, equivalently

And

the respective steering vectors minimize the residual energy after the orthogonal projection of the second received vector onto the space formed by the second received vector.

It should be noted that the determination is made by the formula (15)

And

in equation (15)

The method is a conjugate transpose of a steering vector matrix formed by steering vectors corresponding to any two different directions of arrival in a second direction of arrival set and steering vectors corresponding to a plurality of determined first target directions of arrival, that is, after a plurality of first target directions of arrival are determined, the steering vectors corresponding to the plurality of first target directions of arrival can be added to the set

And in equation (15)

At this time, the process of the present invention,

the first target direction of arrival is included in the first target direction of arrival.

And the second received vector may be calculated according to equation (25):

wherein r' characterizes a second received vector,

Further, the second received vector may also be calculated according to equation (26):

determining two directions of arrival from the second set of directions of arrival

And

then, two energy values corresponding to the two directions of arrival can be calculated by using equations (23) and (24), and based on the relationship between the two energy values, whether the second target direction of arrival indicating the target is the second initial direction of arrival or the determined second target direction of arrival indicating the target is determined

And

by analogy, for a third target discrete point (a discrete point having the largest ordinate value except for the first target discrete point and the second target discrete point), a fourth target discrete point, and the like, the corresponding one or more third target directions of arrival and one or more fourth target directions of arrival can be calculated by adopting the above process. Wherein, after each iterative calculation determines the target direction of arrival, the steering vector of the target direction of arrival can be added to the set

For the next iteration, the number of targets finally determined by the radar system and the set

The number of the target direction of arrival contained in the target is consistent, and the direction of arrival corresponding to each target is a set

The direction of arrival of the corresponding steering vector. In practical application, the target arrival direction (including the first target arrival direction and the second target arrival direction) is determined every timeDirections, etc.) may be recorded in a pre-created set Θ, such that the number of targets identified by the radar system is the number of directions of arrival of the targets contained in the set Θ.

It will be appreciated that for iterative calculations, iteration may be stopped when a corresponding iteration stop condition is met. Therefore, before each iterative computation, whether the iteration stop condition is met currently can be determined, and when the iteration stop condition is not met, the corresponding iterative computation process is executed again until the iterative computation process is stopped when the iteration stop condition is met.

Taking the second iterative computation as an example, before determining the second initial direction of arrival of the second target discrete point, it may be further determined whether the energy value corresponding to the first received energy is smaller than a fourth preset threshold, when the energy value corresponding to the first received vector is greater than or equal to the fourth preset threshold, the second initial direction of arrival of the second target discrete point may be determined according to the coordinate values of the plurality of discrete points and the subsequent computation process of this iteration may be performed, and when the first received vector is smaller than the fourth preset threshold, the iterative computation process may be stopped. As an example, the fourth preset threshold may be a preset fixed value, or may be calculated according to a noise energy value estimated by noise, for example, may be a preset multiple of the noise energy.

Of course, the iteration stop condition may also be to determine whether the number of target directions of arrival is less than a fifth preset threshold, when the number of target directions of arrival that have been determined is less than the fifth preset threshold, a second initial direction of arrival of a second target discrete point may be determined according to coordinate values of the plurality of discrete points and a subsequent calculation process of this iteration may be performed, and when the number of target directions of arrival that have been determined is greater than or equal to the fifth preset threshold, the iteration calculation process may be stopped. As an example, the fifth preset threshold may be smaller than the number of components of the first receiving vector (the number of receiving channels of the echo signal), such as the number of components is reduced by the same; or may be a preset fixed value; the first time of the iterative computation may be an estimated value, for example, K peaks may be predicted to exist in the first time of the iterative computation, and the fifth preset threshold may be K.

In this embodiment, after the first target discrete point with the largest longitudinal coordinate value is determined, the lateral coordinate value of the first target discrete point is not directly used as the finally determined target direction of arrival, and a plurality of directions of arrival can be further determined near the first target discrete point (i.e., the first direction of arrival set), so that when a plurality of targets in the radar detection area are close to each other, different directions of arrival corresponding to different targets can be determined, that is, the radar system can recognize the plurality of targets, thereby preventing the radar system from recognizing the plurality of targets as one target only based on one determined direction of arrival as much as possible, and further improving the accuracy of the number of targets detected by the radar system.

In addition, the embodiment of the application also provides a device for determining the direction of arrival. Referring to fig. 4, fig. 4 is a schematic structural diagram illustrating an apparatus for determining a direction of arrival according to an embodiment of the present application, where the apparatus 400 may specifically include:

an obtaining module 401, configured to obtain original target data;

a DBF processing module 402, configured to perform Digital Beam Forming (DBF) processing on the original target data to obtain target data to be confirmed;

a determining module 403, configured to use any one target to be confirmed in the target data to be confirmed as a first target; and

a search module 404, configured to perform a maximum likelihood ML search operation on the first target;

the searching module 404 is specifically configured to obtain an angle value of the first target; based on a preset angle threshold value, and with the angle value of the first target as a center, obtaining an angle interval to be confirmed; and performing at least two-dimensional ML search in the angle interval to be confirmed to confirm the number of real targets corresponding to the first target.

In a possible implementation, the obtaining module 401 is specifically configured to obtain an echo signal; and performing digital-to-analog conversion and fast Fourier transform on the echo signal to obtain the original target data: the original target data comprises at least one target to be confirmed, distance dimensional data of each target to be confirmed and speed dimensional data of each target to be confirmed.

In a possible implementation manner, the obtaining module 401 is further configured to continue constant false alarm rate processing CFAR after the fast fourier transform to obtain the original target data.

In a possible implementation manner, the determining module 403 is specifically configured to use, as the first target, a target to be confirmed with the largest DBF synthesis energy in the target data to be confirmed.

In a possible implementation, the apparatus 400 further includes:

the judging module is used for judging whether the ML searching operation needs to be carried out on the targets to be confirmed which are the targets to be confirmed and have the maximum DBF synthetic energy in the target data to be confirmed according to a preset stopping condition after the ML searching operation is carried out on the targets to be confirmed which are the targets to be confirmed and have the maximum DBF synthetic energy in the target data to be confirmed; if the ML search operation needs to be carried out on the remaining targets to be confirmed, taking the target to be confirmed with the largest DBF synthetic energy in the remaining targets to be confirmed as the first target and carrying out the ML search operation based on the current received vector; sequentially circulating until the ML search operation is not required to be performed on the remaining targets to be confirmed in the target data to be confirmed according to the preset stop condition; and determining the current receiving vector according to the receiving vector corresponding to the last ML searching operation.

In a possible embodiment, the search module 404 is specifically configured to perform a two-dimensional ML search in the angle interval to be confirmed.

In a possible implementation, the apparatus 400 further includes:

the output module is used for outputting the angle information of the first target as a real target angle signal if the number of the real targets corresponding to the first target is 1; and if the number of the real targets corresponding to the first target is more than 1, acquiring the angle information of each real target and replacing the angle information of the first target for outputting.

In a possible implementation manner, the searching module 404 is specifically configured to perform at least two-dimensional ML search in the angle interval to be confirmed to obtain at least two target angles; if the at least two target angles are distributed on two sides of the angle of the first target when being arranged in sequence according to the value, the number of the real targets corresponding to the first target is larger than 1.

It should be noted that, the apparatus for determining a direction of arrival described in this embodiment corresponds to the method for determining a direction of arrival described in the embodiment of the method shown in fig. 2, and specific implementations of the modules and units in this embodiment may be described with reference to relevant points in the embodiment of the method shown in fig. 2, which are not described herein again.

In addition, the embodiment of the application also provides a device for determining the direction of arrival. Referring to fig. 5, fig. 5 is a schematic structural diagram illustrating an apparatus for determining a direction of arrival according to an embodiment of the present application, where the apparatus 500 may specifically include:

an obtaining module 501, configured to obtain a plurality of discrete points, where the discrete points are obtained at least by performing digital beamforming on an echo signal, a horizontal coordinate of the discrete point represents a direction of arrival, and a vertical coordinate of the discrete point represents an energy value or a power value;

a first determining module 502, configured to determine a first initial direction of arrival of a first target discrete point according to coordinate values of the plurality of discrete points, where a ordinate value of the first target discrete point in the plurality of discrete points is the largest;

a second determining module 503, configured to determine a first direction of arrival set according to the first initial direction of arrival, where the first direction of arrival set includes directions of arrival corresponding to a plurality of discrete points, and an absolute value of a difference between each direction of arrival in the first direction of arrival set and the first initial direction of arrival does not exceed a first preset threshold;

a third determining module 504, configured to determine, according to a steering vector and a first receiving vector corresponding to each direction of arrival in the first direction of arrival set, a plurality of first target directions of arrival in the first direction of arrival set, where the first receiving vector is obtained according to echo signals received by a plurality of receiving channels.

In a possible implementation, the third determining module 504 includes:

a first determining unit, configured to determine, according to a steering vector corresponding to each direction of arrival in the first direction of arrival set and the first receiving vector, a first direction of arrival and a second direction of arrival from the first direction of arrival set, where steering vectors corresponding to the first direction of arrival and the second direction of arrival respectively maximize a parameter of an orthogonal projection of the first receiving vector on a space formed by the first receiving vector.

The first calculating unit is used for calculating a first energy value according to the guiding vector corresponding to the first initial direction of arrival and the first receiving vector;

a second calculating unit, configured to calculate a second energy value according to a first direction of arrival, a second direction of arrival, a steering vector corresponding to the first direction of arrival, a steering vector corresponding to the second direction of arrival, and the first receiving vector in the first direction of arrival set;

and the second determining unit is used for determining the first direction of arrival and the second direction of arrival as a first target direction of arrival according to the magnitude relation between the first energy value and the second energy value.

In a possible implementation, the apparatus 500 further includes:

a fourth determining module, configured to determine the first initial direction of arrival as a first target direction of arrival when a ratio of the second energy value to the first energy value is smaller than a third preset threshold, or a difference between the first energy value and the second energy value is smaller than noise energy.

In a possible implementation, the apparatus 500 further includes:

a fifth determining module, configured to determine a second initial direction of arrival of a second target discrete point according to coordinate values of the multiple discrete points, where a longitudinal coordinate value of the second target discrete point is the largest except for the first target discrete point;

a sixth determining module, configured to determine a second direction-of-arrival set according to the second initial direction of arrival, where the second direction-of-arrival set includes directions of arrival corresponding to the multiple discrete points, and an absolute value of a difference between each direction of arrival in the second direction-of-arrival set and the second initial direction of arrival does not exceed a second preset threshold;

a seventh determining module, configured to determine one or more second target directions of arrival in the second direction of arrival set according to the steering vector corresponding to each direction of arrival in the second direction of arrival set, the steering vectors of the plurality of first target directions of arrival, and a second receiving vector, where the second receiving vector is obtained by calculation according to the first receiving vector and the steering vector corresponding to the first initial direction of arrival.

In a possible implementation, the first determining module 502 includes:

the equal interval selecting unit is used for selecting discrete points from the plurality of discrete points at equal intervals to obtain a first discrete point set;

a third determining unit, configured to determine a first discrete point in the first discrete point set having a maximum ordinate value;

a selecting unit, configured to select, from the multiple discrete points, a discrete point whose interval with the first discrete point does not exceed a preset interval, to obtain a second discrete point set;

a fourth determining unit, configured to determine the discrete point with the largest ordinate value in the second set of discrete points as the first target discrete point, and determine the first initial direction of arrival according to the abscissa value of the first target discrete point.

It should be noted that, the apparatus for determining a direction of arrival described in this embodiment corresponds to the method for determining a direction of arrival described in the method embodiment shown in fig. 3, and specific implementations of the modules and units in this embodiment may be described with reference to relevant points in the method embodiment shown in fig. 3, which is not described herein again.

In addition, the embodiment of the application also provides equipment. Referring to fig. 6, fig. 6 shows a schematic hardware structure diagram of an apparatus in an embodiment of the present application, where the apparatus 600 includes a processor 601 and a memory 602:

the memory 602 is used for storing program codes and transmitting the program codes to the processor 601;

the processor 601 is configured to perform the following steps according to instructions in the program code:

acquiring a plurality of discrete points, wherein the discrete points are obtained at least by performing digital beam forming processing on echo signals, the abscissa of each discrete point represents the direction of arrival, and the ordinate of each discrete point represents an energy value or a power value;

determining a first initial direction of arrival of a first target discrete point according to the coordinate values of the plurality of discrete points, wherein the longitudinal coordinate value of the first target discrete point in the plurality of discrete points is the largest;

determining a first direction of arrival set according to the first initial direction of arrival, wherein the first direction of arrival set comprises directions of arrival corresponding to a plurality of discrete points, and the absolute value of the difference between each direction of arrival in the first direction of arrival set and the first initial direction of arrival does not exceed a first preset threshold;

and determining a plurality of first target directions of arrival in the first direction of arrival set according to the steering vector and the first receiving vector corresponding to each direction of arrival in the first direction of arrival set, wherein the first receiving vector is obtained according to echo signals received by a plurality of receiving channels.

Further, the processor 601 is configured to execute the specific steps described in the above-mentioned method embodiments or other steps according to the instructions in the program code.

In one embodiment, the present application further provides an integrated circuit comprising:

the receiving end is used for receiving echo signals; and

the digital signal processing module is used for carrying out digital signal processing on the echo signal so as to realize target detection;

the digital function module is further configured to determine angle information of each target by using the method for determining a direction of arrival described in the above embodiment when the target detection is implemented.

Further, the integrated circuit may be a chip structure, such as a millimeter wave radar chip. Of course, other hardware implementations of the integrated circuit are possible.

In one embodiment, the present application also provides a radio device comprising: a carrier; the integrated circuit of the above embodiment is disposed on the carrier; an antenna disposed on the carrier; the integrated circuit is connected with the antenna through the first transmission line and used for receiving and transmitting radio signals. The carrier can be a Printed Circuit Board (PCB), and the first transmission line can be a PCB wiring line. In addition, the integrated circuit can be integrated with the antenna to form a device such as AiP.

In one embodiment, the present application further provides an apparatus comprising: an apparatus body; and a radio device as in the above embodiment provided on the apparatus body; wherein the radio device is used for object detection and/or communication.

Specifically, on the basis of the above-described embodiments, in one embodiment of the present application, the radio device may be provided outside the apparatus body, in another embodiment of the present application, the radio device may be provided inside the apparatus body, and in other embodiments of the present application, the radio device may be provided partly inside the apparatus body and partly outside the apparatus body. The present application is not limited thereto, as the case may be.

It should be noted that the radio device can perform functions such as object detection and communication by transmitting and receiving signals.

In an alternative embodiment, the device body may be a component and a product applied to fields such as smart home, transportation, smart home, consumer electronics, monitoring, industrial automation, in-cabin detection, health care, and the like; for example, the device body can be an intelligent transportation device (such as an automobile, a bicycle, a motorcycle, a ship, a subway, a train and the like), a security device (such as a camera), an intelligent wearable device (such as a bracelet, glasses and the like), an intelligent household device (such as a television, an air conditioner, an intelligent lamp and the like), various communication devices (such as a mobile phone, a tablet personal computer and the like), a barrier gate, an intelligent traffic indicator lamp, an intelligent indicator board, a traffic camera, various industrial manipulators (or robots) and the like, and can also be various instruments for detecting vital sign parameters and various devices carrying the instruments. The radio device may be a radio device as set forth in any embodiment of the present application, and the structure and the operation principle of the radio device have been described in detail in the above embodiments, which are not described in detail herein.

The embodiment of the application also provides a computer readable storage medium. The methods described in the above embodiments may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media may include computer storage media and communication media, and may include any medium that can communicate a computer program from one place to another. A storage medium may be any target medium that can be accessed by a computer.

As an alternative design, a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that is targeted for carriage or stores desired program code in the form of instructions or data structures and that is accessible by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, digital words, and it is understood that the present invention can be embodied as a software product, which can be stored in a storage medium, such as read-only memory (ROM)/RAM, magnetic disc, optical disc, etc., and includes instructions for causing a computer device (which can be a personal computer, a server, or a network communication device such as a router, etc.) to execute the methods described in the various embodiments or parts of the embodiments of the present application.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the apparatus embodiment, since it is substantially similar to the method embodiment, it is relatively simple to describe, and reference may be made to some descriptions of the method embodiment for relevant points. The above-described embodiments of the apparatus are merely illustrative, and the modules described as separate parts may or may not be physically separate, and the parts displayed as modules may or may not be physical modules, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

The above description is only an exemplary embodiment of the present application, and is not intended to limit the scope of the present application.

Claims

1. A method of determining a direction of arrival, comprising:

acquiring original target data;

carrying out Digital Beam Forming (DBF) processing on the original target data to obtain target data to be confirmed;

taking any target to be confirmed in the target data to be confirmed as a first target; and

performing a Maximum Likelihood (ML) search operation on the first target;

wherein the ML search operation includes:

obtaining an angle value of the first target;

based on a preset angle threshold value, and with the angle value of the first target as a center, obtaining an angle interval to be confirmed; and

and performing at least two-dimensional ML search in the angle interval to be confirmed to confirm the number of real targets corresponding to the first target.

2. The method of claim 1, wherein the obtaining raw target data comprises:

acquiring an echo signal; and

performing digital-to-analog conversion and fast Fourier transform on the echo signal to obtain the original target data,

the original target data comprises at least one target to be confirmed, distance dimensional data of each target to be confirmed and speed dimensional data of each target to be confirmed.

3. The method of claim 2, wherein the obtaining raw target data further comprises:

and after the fast Fourier transform, continuously processing CFAR to obtain the original target data.

4. The method according to claim 1, wherein the setting any one of the target data to be confirmed as a first target comprises:

and taking the target to be confirmed with the maximum DBF synthetic energy in the target data to be confirmed as the first target.

5. The method of claim 4, further comprising:

after the ML search operation is performed on the target to be confirmed with the maximum DBF synthetic energy in the target data to be confirmed, judging whether the ML search operation needs to be performed on the remaining targets to be confirmed in the target data to be confirmed according to a preset stop condition;

if the ML search operation needs to be carried out on the remaining targets to be confirmed, taking the target to be confirmed with the largest DBF synthetic energy in the remaining targets to be confirmed as the first target and carrying out the ML search operation based on the current received vector;

sequentially circulating until the ML search operation is not required to be performed on the remaining targets to be confirmed in the target data to be confirmed according to the preset stop condition;

and determining the current receiving vector according to the receiving vector corresponding to the last ML searching operation.

6. The method according to claim 5, wherein the preset stop condition is that an energy value corresponding to a received vector corresponding to each round of ML search operation is smaller than a preset energy threshold;

and/or the number of all the determined real targets is larger than a preset number threshold.

7. The method of claim 1, wherein performing an ML search in at least two dimensions in the to-be-confirmed angular interval comprises:

and performing two-dimensional ML search in the angle interval to be confirmed.

8. The method of claim 1, further comprising:

if the number of the real targets corresponding to the first target is 1, outputting the angle information of the first target as a real target angle signal; and

and if the number of the real targets corresponding to the first target is more than 1, acquiring the angle information of each real target and replacing the angle information of the first target for outputting.

9. The method of claim 8, further comprising:

and if the number of the real targets corresponding to the first target is more than 1, acquiring the power information of each real target and replacing the power information of the first target for output.

10. The method of claim 8, further comprising:

if the number of the real targets corresponding to the first target is larger than 1, the speed of each real target corresponding to the same first target is the same, and the distance of each real target is the same.

11. The method according to any one of claims 1-10, wherein said performing at least two-dimensional ML search in said angle interval to be confirmed to confirm the number of real objects corresponding to said first object comprises:

performing at least two-dimensional ML search in the angle interval to be confirmed to obtain at least two target angles;

if the at least two target angles are distributed on two sides of the angle of the first target when being arranged in sequence according to the value, the number of the real targets corresponding to the first target is larger than 1.

12. The method according to any one of claims 1-10, wherein the ML search comprises a coarse search operation and a fine search operation performed in sequence;

wherein the rough search operation is used for determining a possible value of a real target corresponding to the first target through an interval point search preliminary; and

the fine search operation is used for searching point by point within a range around the maximum possible value to determine the final value of the real target corresponding to the first target.

13. A method of determining a direction of arrival, the method comprising:

14. The method of claim 13, wherein determining a plurality of first target directions of arrival in the first set of directions of arrival from the steering vector corresponding to each direction of arrival in the first set of directions of arrival and a first received vector comprises:

and determining a first direction of arrival and a second direction of arrival from the first direction of arrival set according to the steering vector corresponding to each direction of arrival in the first direction of arrival set and the first receiving vector, wherein the steering vectors corresponding to the first direction of arrival and the second direction of arrival respectively enable a parameter of orthogonal projection of the first receiving vector on a space formed by the first receiving vector to be maximum.

Calculating a first energy value according to the steering vector corresponding to the first initial direction of arrival and the first receiving vector;

calculating a second energy value according to a first direction of arrival, a second direction of arrival, a steering vector corresponding to the first direction of arrival, a steering vector corresponding to the second direction of arrival and the first receiving vector in the first direction of arrival set;

and determining the first direction of arrival and the second direction of arrival as a first target direction of arrival according to the magnitude relation between the first energy value and the second energy value.

15. The method of claim 14, wherein determining the first direction of arrival and the second direction of arrival as a first target direction of arrival according to a magnitude relationship between the first energy value and a second energy value comprises:

and when the ratio of the second energy value to the first energy value is not less than a third preset threshold value and/or the difference value of the first energy value and the second energy value is not less than noise energy, determining the first direction of arrival and the second direction of arrival as a first target direction of arrival.

16. The method of claim 15, further comprising:

and when the ratio of the second energy value to the first energy value is smaller than a third preset threshold value, or the difference value of the first energy value and the second energy value is smaller than noise energy, determining the first initial direction of arrival as a first target direction of arrival.

17. The method of claim 13, further comprising:

determining a second initial direction of arrival of a second target discrete point according to the coordinate values of the plurality of discrete points, wherein the longitudinal coordinate value of the second target discrete point is the largest except the first target discrete point;

determining a second direction-of-arrival set according to the second initial direction of arrival, wherein the second direction-of-arrival set comprises directions of arrival corresponding to the plurality of discrete points, and the absolute value of the difference between each direction of arrival in the second direction-of-arrival set and the second initial direction of arrival does not exceed a second preset threshold;

and determining one or more second target directions of arrival in the second direction of arrival set according to the steering vector corresponding to each direction of arrival in the second direction of arrival set, the steering vectors of the plurality of first target directions of arrival, and a second receiving vector, wherein the second receiving vector is obtained by calculation according to the first receiving vector and the steering vector corresponding to the first initial direction of arrival.

18. The method of claim 17, wherein determining a second initial direction of arrival for a second target discrete point based on the coordinate values of the plurality of discrete points comprises:

and when the energy value corresponding to the first receiving vector is not less than a fourth preset threshold value and/or the number of the determined target directions of arrival is less than a fifth preset threshold value, determining a second initial direction of arrival of a second target discrete point according to the coordinate values of the plurality of discrete points.

19. The method of any one of claims 13 to 18, wherein said determining a first initial direction of arrival for a first target discrete point from coordinate values of said plurality of discrete points comprises:

selecting discrete points at equal intervals from the plurality of discrete points to obtain a first discrete point set;

determining a first discrete point in the first set of discrete points having a maximum ordinate value;

selecting discrete points from the plurality of discrete points, wherein the interval between the discrete points and the first discrete point does not exceed a preset interval, and obtaining a second discrete point set;

and determining the discrete point with the maximum ordinate value in the second discrete point set as the first target discrete point, and determining the first initial direction of arrival according to the abscissa value of the first target discrete point.

20. An apparatus for determining a direction of arrival, the apparatus comprising:

an obtaining module, configured to obtain a plurality of discrete points, where the plurality of discrete points are obtained at least by performing digital beamforming on an echo signal, a horizontal coordinate of the discrete point represents a direction of arrival, and a vertical coordinate of the discrete point represents an energy value or a power value;

a first determining module, configured to determine a first initial direction of arrival of a first target discrete point according to coordinate values of the plurality of discrete points, where a ordinate value of the first target discrete point in the plurality of discrete points is the largest;

a second determining module, configured to determine a first direction of arrival set according to the first initial direction of arrival, where the first direction of arrival set includes directions of arrival corresponding to a plurality of discrete points, and an absolute value of a difference between each direction of arrival in the first direction of arrival set and the first initial direction of arrival does not exceed a first preset threshold;

a third determining module, configured to determine, according to a steering vector and a first receiving vector that correspond to each direction of arrival in the first direction of arrival set, a plurality of first target directions of arrival in the first direction of arrival set, where the first receiving vector is obtained according to echo signals received by a plurality of receiving channels.

21. The apparatus of claim 20, wherein the third determining module comprises:

22. A computer device, the computer device comprising a processor and a memory:

the memory is used for storing program codes and transmitting the program codes to the processor;

the processor is configured to perform the method of determining a direction of arrival of any one of claims 1 to 12 or the method of determining a direction of arrival of any one of claims 13 to 19 according to instructions in the program code.

23. An integrated circuit, comprising:

the receiving end is used for receiving echo signals; and

wherein the digital function module is further configured to determine the angle information of each target by using the method of any one of claims 1-19 when the target detection is performed.

24. The integrated circuit of claim 23, wherein the integrated circuit is a millimeter wave radar chip.

25. A radio device, comprising:

a carrier;

an integrated circuit as claimed in any one of claims 23 or 24, disposed on a carrier;

an antenna disposed on the carrier or on which a device AiP structure is disposed integral with the integrated circuit;

the integrated circuit is connected with the antenna and used for transmitting and receiving radio signals.

26. An apparatus, comprising:

an apparatus body; and

the radio of claim 25 disposed on the equipment body;

wherein the radio device is used for object detection and/or communication.