CN114185019A - Intelligent reflecting surface assisted radar communication cooperative target detection method and electronic equipment - Google Patents

Intelligent reflecting surface assisted radar communication cooperative target detection method and electronic equipment Download PDF

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Publication number
CN114185019A
CN114185019A CN202111474150.2A CN202111474150A CN114185019A CN 114185019 A CN114185019 A CN 114185019A CN 202111474150 A CN202111474150 A CN 202111474150A CN 114185019 A CN114185019 A CN 114185019A
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radar
reflecting surface
intelligent reflecting
base station
phase shift
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吕伟
林强
邓斌
李洪力
方其庆
余娟
张丛胜
王晶晶
谷成刚
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Air Force Early Warning Academy
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
    • G01S7/411—Identification of targets based on measurements of radar reflectivity
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/40—Means for monitoring or calibrating
    • G01S7/4052—Means for monitoring or calibrating by simulation of echoes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/145—Passive relay systems

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
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Abstract

The invention provides an intelligent reflector assisted radar communication cooperative target detection method. By using the intelligent reflecting surface, the received signal strength of the MIMO radar receiving array is improved, and the radar detection performance is enhanced; simultaneously, carrying out target detection by utilizing a communication signal of the radar communication integrated base station; the MIMO radar and radar communication integrated base station cooperatively performs target detection, so that the detection performance is further improved. The invention aims to improve the radar target detection performance by simultaneously utilizing the communication signals of the intelligent reflecting surface and the radar communication integrated base station. The invention also provides corresponding electronic equipment.

Description

Intelligent reflecting surface assisted radar communication cooperative target detection method and electronic equipment
Technical Field
The invention belongs to the technical field of radar detection, and particularly relates to an intelligent reflector assisted radar communication cooperative target detection method and electronic equipment.
Background
A smart reflective surface is a plane composed of a large number of low cost passive reflective elements, each of which is capable of independently phase-changing an incident signal. Currently, research has been conducted to apply intelligent reflective surfaces to wireless communications. By placing the intelligent radiation surface between the sender and the receiver, the receiver can better receive the signals sent by the sender. The document Towards Smart Wireless communication via Intelligent reflection surface A content Survey (IEEE communication Surveys & Tutorials,2020) summarizes and expects the great potential and application prospect of the Intelligent Reflecting surface in Wireless communication. The Intelligent Reflecting Surface also has a certain application potential in the field of Radar, for example, in the document "Intelligent Reflecting Surface-Enhanced Target Detection in MIMO Radar" (IEEE Sensors Letters, 2021). Therefore, the intelligent reflecting surface has great application potential in radar and wireless communication.
In addition, the size and the coverage area of base stations used for communication are getting larger, the base stations also continuously radiate communication signals outwards, and the communication signals of the base stations also generate reflection phenomena when meeting targets. Object detection can also be performed by using communication signals. Therefore, the radar communication integrated base station is also an important development direction in the future, and receives extensive attention and research.
Therefore, if the communication signal and the radar signal are comprehensively utilized for target detection, and the intelligent reflecting surface is reasonably arranged for signal transmission and signal reception, the target detection performance can be further improved.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides an intelligent reflector assisted radar communication cooperative target detection method. By using the intelligent reflecting surface, the received signal strength of the MIMO radar and radar communication integrated base station is improved, and the radar detection performance is improved; meanwhile, the communication signals of the radar communication integrated base station and the radar signals of the MIMO radar are used for target detection, so that the target detection performance is further improved. The invention aims to improve the radar target detection performance by simultaneously utilizing the communication signals of the intelligent reflecting surface and the radar communication integrated base station.
In order to achieve the purpose, the invention provides an intelligent reflector assisted radar communication cooperative target detection method. And intelligent reflecting surfaces are arranged near the radar and communication integrated base station, and the radar and radar communication integrated base station is used for cooperative target detection. When a signal is transmitted, simultaneously adjusting an intelligent reflecting surface near a radar and radar communication integrated base station; and during echo receiving, simultaneously adjusting an intelligent reflecting surface near the radar and radar communication integrated base station. The MIMO radar and radar communication integrated base station simultaneously receives a communication signal echo and a radar signal echo which are directly reflected by a target, and a communication signal echo and a radar signal echo which are reflected by the target through an intelligent reflecting surface. The method specifically comprises the following steps:
step S1: in the signal transmitting stage, according to a target detection direction, gain of a radar antenna and an intelligent reflecting surface, path transmission loss, channel state information between the intelligent reflecting surface near the radar and a radar receiving array and the like, a radar signal processor calculates and obtains an optimized phase shift amount of each array element of the intelligent reflecting surface near the radar, and the radar optimally controls the phase shift amount of each array element of the intelligent reflecting surface near the radar through an intelligent reflecting surface controller.
Considering a narrow-band centralized MIMO radar system, the radar array is equivalent to a linear array, and N antennas are arranged according to a half-wavelength interval; and a single antenna is equivalently installed on the radar communication integrated base station. Intelligent reflecting surface near radar and radar communicationIntelligent reflecting surfaces near the integrated base station are all equivalent to linear arrays, and M are respectively arranged according to half-wavelength intervals1And M2And a reflection array element.
Assuming that the normal included angle between the target position and the MIMO radar array is theta1At a distance of (2), the radar channel to the target is
Figure BDA0003390955510000021
Can be expressed as
Figure BDA0003390955510000022
Wherein
Figure BDA0003390955510000023
As a transmit steering vector of the radar array, theta1Is the normal included angle between the target and the radar array; g1Due to antenna gain, fading and phase shift caused by path transmission.
The channel from the radar to the target through the intelligent reflecting surface nearby is
Figure BDA0003390955510000031
Can be expressed as
Figure BDA0003390955510000032
Wherein
Figure BDA0003390955510000033
Is a guide vector of an intelligent reflecting surface near the radar, theta4The normal included angle between the target and the intelligent reflecting surface is set; g2The method is characterized in that the method comprises the following steps of (1) fading and phase shift caused by radar array gain, intelligent reflecting surface gain and path transmission;
Figure BDA0003390955510000034
is a diagonal matrix, the nth diagonal element of which is the phase shift quantity of the reflection array element n of the intelligent reflection surface
Figure BDA0003390955510000035
Elements of construction
Figure BDA0003390955510000036
Is a channel matrix between the radar and the intelligent reflecting surface.
The channel from the radar communication integrated base station to the target is h3Can be represented as
h3＝g3，
Wherein g is3And the fading and the phase shift caused by the antenna gain and the path transmission of the radar communication integrated base station are shown.
The channel from the radar communication integrated base station to the target through the adjacent intelligent reflecting surface is h4Can be represented as
Figure BDA0003390955510000037
Wherein
Figure BDA0003390955510000038
Is a guide vector of a smart reflecting surface near a radar communication integrated base station'4The normal included angle between the target and the intelligent reflecting surface is set; g4The antenna gain, the intelligent reflecting surface gain and the fading and phase shift caused by path transmission of the radar communication integrated base station are obtained;
Figure BDA0003390955510000039
is a diagonal matrix, the nth diagonal element of the diagonal matrix is the phase shift quantity of the array element n reflected by the intelligent reflecting surface
Figure BDA00033909555100000310
Elements of construction
Figure BDA00033909555100000311
Is a channel matrix between the radar and the intelligent reflecting surface.
When the target echo signal is received, the target-to-radar channel is
Figure BDA00033909555100000312
Can be expressed as
Figure BDA00033909555100000313
Wherein
Figure BDA00033909555100000314
A receiving steering vector of the radar array;
Figure BDA00033909555100000315
due to antenna gain of the radar, gain of the intelligent reflecting surface, fading and phase shift caused by path transmission.
The channel from the target to the radar through the intelligent reflecting surface is
Figure BDA00033909555100000316
Can be expressed as
Figure BDA0003390955510000041
Wherein
Figure BDA0003390955510000042
When receiving echo, the antenna gain of radar, the gain of intelligent reflecting surface and the fading and phase shift caused by path transmission;
Figure BDA0003390955510000043
receiving a steering vector of a target echo for the intelligent reflecting surface;
Figure BDA0003390955510000044
is a diagonal matrix, the nth diagonal element of which is the phase shift amount of the reflection array element n when receiving the echo
Figure BDA0003390955510000045
Elements of construction
Figure BDA0003390955510000046
Is a channel matrix between the intelligent reflecting surface and the radar.
When the target echo signal is received, the channel from the target to the radar communication integrated base station is
Figure BDA0003390955510000047
Can be expressed as
Figure BDA0003390955510000048
Wherein
Figure BDA0003390955510000049
And the fading and the phase shift caused by the antenna gain and the path transmission of the radar communication integrated base station are shown.
The target passes through the intelligent reflecting surface to reach the radar communication integrated base station
Figure BDA00033909555100000410
Can be expressed as
Figure BDA00033909555100000411
Wherein
Figure BDA00033909555100000412
In order to receive the echo, the antenna gain, the intelligent reflecting surface gain and the fading and phase shift caused by path transmission of the radar communication integrated base station;
Figure BDA00033909555100000413
receiving a steering vector of a target echo for the intelligent reflecting surface;
Figure BDA00033909555100000414
is a diagonal matrix, the nth diagonal element of which is the phase shift amount of the reflection array element n when receiving the echo
Figure BDA00033909555100000415
Elements of construction
Figure BDA00033909555100000416
Is a channel matrix between the intelligent reflecting surface and the radar.
Signals transmitted by the radar and radar communication integrated base station are assumed to be orthogonal to each other and are respectively expressed as
Figure BDA00033909555100000417
And
Figure BDA00033909555100000418
l is the length of the signal after sampling, and
Figure BDA00033909555100000419
Figure BDA00033909555100000420
INis an N-dimensional identity matrix. Assuming that the transmitting signals of the radar and radar communication integrated base station reach the target distance at the same time, and the radar and radar communication integrated base station have transmitting signal information SraAnd sbs. The signals received by the MIMO radar can be expressed as
Figure BDA00033909555100000421
Wherein
Figure BDA00033909555100000422
Is a noise matrix; praIs the transmission power of the radar; pbsIs the transmit power of the base station; alpha is alpharaAnd alphabsThe reflection cross section area of the target relative to the radar and radar communication integrated base station is shown.
The received signal passes through and SraAnd sbsAfter matched filtering, can be expressed as
Figure BDA0003390955510000051
Wherein
Figure BDA0003390955510000052
Is a matrix of Gaussian noise after matched filtering.
Matrix X of received signals1Vectorization is expressed as
Figure BDA0003390955510000053
Wherein h is12＝h1+h2，h34＝h3+h4Wherein vec (X) denotes subjecting X to a vectorization operation,
Figure BDA0003390955510000054
representing the Kronecker product.
The signal received by the radar communication integration base station can be expressed as
Figure BDA0003390955510000055
Wherein
Figure BDA00033909555100000513
Is a noise matrix.
The signal received by the radar communication integrated base station passes through the S-channelraAnd sbsAfter matched filtering, can be expressed as
Figure BDA0003390955510000057
Wherein
Figure BDA0003390955510000058
Is a matrix of Gaussian noise after matched filtering.
Matrix X of received signals2Vectorization is expressed as
Figure BDA0003390955510000059
X is to be1And x2Are combined into a vector x of
Figure BDA00033909555100000510
Wherein
Figure BDA00033909555100000511
In order to maximise the signal-to-noise ratio of the received signal, i.e.
Figure BDA00033909555100000512
Maximization, where | · |. non-calculation2Representing the square of the 2 norm. In order to maximize the signal-to-noise ratio of the received signal, it is first necessary to aim at the signal transmission period, h12Expression is carried out on phase shift quantity matrix psi of intelligent reflecting surface near radar1，tIs optimized to meet
Figure BDA0003390955510000061
And (4) maximizing. The phase shift quantity matrix psi of the intelligent reflecting surface near the radar can be processed by a coordinate descent method or a convex optimization method1，tAnd carrying out optimization solution to obtain the phase shift quantity of each array element of the intelligent reflecting surface, and carrying out corresponding phase shift on the intelligent reflecting surface according to the phase shift quantity.
Step S2: in the signal transmitting stage, according to a target detection direction, the gain of the antenna and the intelligent reflecting surface of the radar communication integrated base station, the path transmission loss, the channel state information between the intelligent reflecting surface near the radar communication integrated base station and the like, a radar signal processor calculates and obtains the optimized phase shift amount of each array element of the intelligent reflecting surface near the radar communication integrated base station, and the radar carries out corresponding phase shift optimization control on each array element of the intelligent reflecting surface near the radar communication integrated base station through an intelligent reflecting surface controller.
To make it possible toMaximising the signal-to-noise ratio of the received signal, i.e.
Figure BDA0003390955510000062
Maximization, required for the signal transmission period, over h34Phase shift quantity matrix psi of intelligent reflecting surface near radar communication integrated base station in expression2，tOptimizing to satisfy Pbs αbs h34||2And (4) maximizing. The phase shift quantity matrix psi of the intelligent reflecting surface near the radar communication integrated base station can be processed by a coordinate descent method or a convex optimization method2，tAnd (6) carrying out optimization solution.
Step S3: in the echo signal receiving stage, according to a target detection direction, gain of the radar antenna and the intelligent reflecting surface, path transmission loss, channel state information between the intelligent reflecting surface near the radar and the radar receiving array and the like, the radar signal processor calculates and obtains the phase shift amount of each array element of the intelligent reflecting surface near the radar, and the radar carries out corresponding phase shift optimization control on each array element of the intelligent reflecting surface near the radar through the intelligent reflecting surface controller.
In order to maximise the signal-to-noise ratio of the received signal, i.e.
Figure BDA0003390955510000063
Maximization, required for the duration of echo signal reception
Figure BDA0003390955510000071
Expression is carried out on phase shift quantity matrix psi of intelligent reflecting surface near radar1，rIs optimized to meet
Figure BDA0003390955510000072
And (4) maximizing. The phase shift quantity matrix psi of the intelligent reflecting surface near the radar can be processed by a coordinate descent method or a convex optimization method1，rAnd (6) carrying out optimization solution.
Step S4: in the echo signal receiving stage, according to a target detection direction, the gain of the radar communication integrated base station antenna and the intelligent reflecting surface, the path transmission loss, the channel state information between the intelligent reflecting surface near the radar communication integrated base station and the like, the radar signal processor calculates and obtains the phase shift amount of each array element of the intelligent reflecting surface near the radar communication integrated base station, and the radar carries out corresponding phase shift optimization control on each array element of the intelligent reflecting surface near the radar communication integrated base station through the intelligent reflecting surface controller.
In order to maximise the signal-to-noise ratio of the received signal, i.e.
Figure BDA0003390955510000073
Maximization, required for the duration of echo signal reception
Figure BDA0003390955510000074
Phase shift quantity matrix psi of intelligent reflecting surface near radar communication integrated base station in expression2，rIs optimized to meet
Figure BDA0003390955510000075
And (4) maximizing. The phase shift quantity matrix psi of the intelligent reflecting surface near the radar communication integrated base station can be processed by a coordinate descent method or a convex optimization method2，rAnd (6) carrying out optimization solution.
Step S5: and the radar communication integrated base station transmits the received signal to the MIMO radar for cooperative processing, and target detection is carried out. If the detection statistic is larger than the threshold value, a target exists at the distance; otherwise, there is no target at that distance.
According to the Neyman-Pearson criterion, the detection statistic T is:
Figure BDA0003390955510000076
wherein δ is a threshold determined according to the false alarm rate; h0Indicating that there is no target at that distance; h1Indicating that there is a target at that distance; | x | non-conducting phosphor2Representing the square of the 2 norm of x.
Compared with the prior art, the invention has the following beneficial effects: according to the radar communication cooperative target detection method based on the intelligent reflecting surface, provided by the invention, target detection is carried out by simultaneously utilizing the MIMO radar signal and the communication signal of the radar communication integrated base station, the phase shift amount of the reflecting array elements on the intelligent reflecting surface near the radar and the intelligent reflecting surface near the radar communication integrated base station is controlled, the signal-to-noise ratio of a target echo signal received by the radar is improved, and thus the target detection performance is improved.
Drawings
FIG. 1 is a schematic diagram of an intelligent reflector assisted radar communication cooperative target detection system in an embodiment of the present invention;
FIG. 2 is a schematic flow chart of a method for detecting a cooperative target by an intelligent reflector assisted radar and communication according to an embodiment of the present invention;
fig. 3 is a schematic signal-to-noise ratio gain diagram of an intelligent reflector assisted radar and communication cooperative target detection method in an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The intelligent transmitting surface can flexibly change the phase and the amplitude of each array element on the reflecting surface according to the wireless environment, so that the signal power of a receiving party is increased or the interference signal of the receiving party is inhibited. The invention utilizes the intelligent reflecting surface to enhance the signal intensity of the MIMO radar receiving array and improve the performance of target detection. Meanwhile, the communication signal of the radar communication integrated base station is utilized to cooperatively detect, so that the target detection performance is further improved.
As shown in fig. 1, intelligent reflecting surfaces are placed near both the radar and MIMO radar, and the radar and radar integrated base station performs cooperative target detection. The time synchronization and the related information sharing are realized between the radar signal processor of the MIMO radar and the radar communication integrated base station through the transmission of control signals. The radar signal processor is respectively connected with the intelligent reflecting surface controller 1 and the intelligent reflecting surface controller 2, and optimal control over the intelligent reflecting surface 1 and the intelligent reflecting surface 2 is achieved. When a signal is transmitted, simultaneously adjusting an intelligent reflecting surface near a radar and radar communication integrated base station; and during echo receiving, simultaneously adjusting an intelligent reflecting surface near the radar and radar communication integrated base station. The radar communication integrated base station and the MIMO radar simultaneously receive a communication signal echo and a radar signal echo which are directly reflected by a target, and a communication signal echo and a radar signal echo which are reflected by the target echo through the intelligent reflecting surface. The radar communication integrated base station can transmit the received signals to the radar signal processor to be cooperatively processed with the received signals of the MIMO radar. The method specifically comprises the following steps:
step S1: in the signal transmitting stage, according to a target detection direction, gain of a radar antenna and an intelligent reflecting surface, path transmission loss, channel state information between the intelligent reflecting surface near the radar and a radar receiving array and the like, a radar signal processor calculates and obtains an optimized phase shift amount of each array element of the intelligent reflecting surface near the radar, and the radar optimally controls the phase shift amount of each array element of the intelligent reflecting surface near the radar through an intelligent reflecting surface controller.
Considering a narrow-band centralized MIMO radar system, the radar array is equivalent to a linear array, and N antennas are arranged according to a half-wavelength interval; and a single antenna is equivalently installed on the radar communication integrated base station. The intelligent reflecting surface near the radar and the intelligent reflecting surface near the radar communication integrated base station are equivalent to a linear array, and M are respectively arranged according to the half-wavelength interval1And M2And a reflection array element.
Assuming that the target is positioned at an angle theta with the normal direction of the radar array1At a distance of (2), the radar channel to the target is
Figure BDA0003390955510000091
Can be expressed as
Figure BDA0003390955510000092
Wherein
Figure BDA0003390955510000093
As a transmit steering vector of the radar array, theta1Is the normal included angle between the target and the radar array; g1Due to antenna gain, fading and phase shift caused by path transmission.
The channel from the radar to the target through the intelligent reflecting surface nearby is
Figure BDA0003390955510000094
Can be expressed as
Figure BDA0003390955510000095
Wherein
Figure BDA0003390955510000096
Is a guide vector of an intelligent reflecting surface near the radar, theta4The normal included angle between the target and the intelligent reflecting surface is set; g2The method is characterized in that the method comprises the following steps of (1) fading and phase shift caused by radar array gain, intelligent reflecting surface gain and path transmission;
Figure BDA0003390955510000097
is a diagonal matrix, the nth diagonal element of which is the phase shift quantity of the reflection array element n of the intelligent reflection surface
Figure BDA0003390955510000101
Elements of construction
Figure BDA0003390955510000102
Is a channel matrix between the radar and the intelligent reflecting surface.
The channel from the radar communication integrated base station to the target is h3Can be represented as
h3＝g3，
Wherein g is3Shows the gain of the antenna of the base station due to the integration of radar communicationFading and phase shift caused by path transmission.
The channel from the radar communication integrated base station to the target through the adjacent intelligent reflecting surface is h4Can be represented as
Figure BDA0003390955510000103
Wherein
Figure BDA0003390955510000104
Is a guide vector of a smart reflecting surface near a radar communication integrated base station'4The normal included angle between the target and the intelligent reflecting surface is set; g4The antenna gain, the intelligent reflecting surface gain and the fading and phase shift caused by path transmission of the radar communication integrated base station are obtained;
Figure BDA0003390955510000105
is a diagonal matrix, the nth diagonal element of the diagonal matrix is the phase shift quantity of the array element n reflected by the intelligent reflecting surface
Figure BDA0003390955510000106
Elements of construction
Figure BDA0003390955510000107
Is a channel matrix between the radar and the intelligent reflecting surface.
When the target echo signal is received, the target-to-radar channel is
Figure BDA0003390955510000108
Can be expressed as
Figure BDA0003390955510000109
Wherein
Figure BDA00033909555100001010
A receiving steering vector of the radar array;
Figure BDA00033909555100001011
due to antenna gain of the radar, gain of the intelligent reflecting surface, fading and phase shift caused by path transmission.
The channel from the target to the radar through the intelligent reflecting surface is
Figure BDA00033909555100001012
Can be expressed as
Figure BDA00033909555100001013
Wherein
Figure BDA00033909555100001018
When receiving echo, the antenna gain of radar, the gain of intelligent reflecting surface and the fading and phase shift caused by path transmission;
Figure BDA00033909555100001014
receiving a steering vector of a target echo for the intelligent reflecting surface;
Figure BDA00033909555100001015
is a diagonal matrix, the nth diagonal element of which is the phase shift amount of the reflection array element n when receiving the echo
Figure BDA00033909555100001016
Elements of construction
Figure BDA00033909555100001017
Is a channel matrix between the intelligent reflecting surface and the radar.
When the target echo signal is received, the channel from the target to the radar communication integrated base station is
Figure BDA0003390955510000111
Can be expressed as
Figure BDA0003390955510000112
Wherein
Figure BDA0003390955510000113
And the fading and the phase shift caused by the antenna gain and the path transmission of the radar communication integrated base station are shown.
The target passes through the intelligent reflecting surface to reach the radar communication integrated base station
Figure BDA0003390955510000114
Can be expressed as
Figure BDA0003390955510000115
Wherein
Figure BDA0003390955510000116
In order to receive the echo, the antenna gain, the intelligent reflecting surface gain and the fading and phase shift caused by path transmission of the radar communication integrated base station;
Figure BDA0003390955510000117
receiving a steering vector of a target echo for the intelligent reflecting surface;
Figure BDA0003390955510000118
is a diagonal matrix, the nth diagonal element of which is the phase shift amount of the reflection array element n when receiving the echo
Figure BDA0003390955510000119
Elements of construction
Figure BDA00033909555100001110
Is a channel matrix between the intelligent reflecting surface and the radar.
Signals transmitted by the radar and radar communication integrated base station are assumed to be orthogonal to each other and are respectively expressed as
Figure BDA00033909555100001111
And
Figure BDA00033909555100001112
up to the length after signal sampling and
Figure BDA00033909555100001113
Figure BDA00033909555100001114
INis an N-dimensional identity matrix. Assuming that the transmitting signals of the radar and radar communication integrated base station reach the target distance at the same time, and the radar and radar communication integrated base station have transmitting signal information SraAnd sbs. The signals received by the MIMO radar can be expressed as
Figure BDA00033909555100001115
Wherein
Figure BDA00033909555100001116
Is a noise matrix; praIs the transmission power of the radar; pbsIs the transmit power of the base station; alpha is alpharaAnd alphabsThe reflection cross section area of the target relative to the radar and radar communication integrated base station is shown.
The received signal passes through and SraAnd sbsAfter matched filtering, can be expressed as
Figure BDA00033909555100001117
Wherein
Figure BDA00033909555100001118
Is a matrix of Gaussian noise after matched filtering.
Matrix X of received signals1Vectorization is expressed as
Figure BDA00033909555100001119
Wherein h is12＝h1+h2，h34＝h3+h4Wherein vec (X) denotes subjecting X to a vectorization operation,
Figure BDA0003390955510000121
representing the Kronecker product.
The signal received by the radar communication integration base station can be expressed as
Figure BDA0003390955510000122
Wherein
Figure BDA0003390955510000123
Is a noise matrix.
The signal received by the radar communication integrated base station passes through the S-channelraAnd sbsAfter matched filtering, can be expressed as
Figure BDA0003390955510000124
Wherein
Figure BDA0003390955510000125
Is a matrix of Gaussian noise after matched filtering.
Matrix X of received signals2Vectorization is expressed as
Figure BDA0003390955510000126
X is to be1And x2Are combined into a vector x of
Figure BDA0003390955510000127
Wherein
Figure BDA0003390955510000128
In order to maximise the signal-to-noise ratio of the received signal, i.e.
Figure BDA0003390955510000129
Maximization, where | · |. non-calculation2Representing the square of the 2 norm. In order to maximize the signal-to-noise ratio of the received signal, it is first necessary to aim at the signal transmission period, h12Expression is carried out on phase shift quantity matrix psi of intelligent reflecting surface near radar1，tIs optimized to meet
Figure BDA00033909555100001210
And (4) maximizing. The phase shift quantity matrix psi of the intelligent reflecting surface near the radar can be processed by a coordinate descent method or a convex optimization method1，tAnd carrying out optimization solution to obtain the phase shift quantity of each array element of the intelligent reflecting surface, and carrying out corresponding phase shift on the intelligent reflecting surface according to the phase shift quantity.
Step S2: in the signal transmitting stage, according to a target detection direction, the gain of the antenna and the intelligent reflecting surface of the radar communication integrated base station, the path transmission loss, the channel state information between the intelligent reflecting surface near the radar communication integrated base station and the like, a radar signal processor calculates and obtains the optimized phase shift amount of each array element of the intelligent reflecting surface near the radar communication integrated base station, and the radar carries out corresponding phase shift optimization control on each array element of the intelligent reflecting surface near the radar communication integrated base station through an intelligent reflecting surface controller.
In order to maximise the signal-to-noise ratio of the received signal, i.e.
Figure BDA0003390955510000131
Maximization, required for the signal transmission period, over h34Phase shift quantity matrix psi of intelligent reflecting surface near radar communication integrated base station in expression2，tOptimizing to satisfy Pbs αbs h34||2And (4) maximizing. The phase shift quantity matrix psi of the intelligent reflecting surface near the radar communication integrated base station can be processed by a coordinate descent method or a convex optimization method2，tAnd (6) carrying out optimization solution.
Step S3: in the echo signal receiving stage, according to a target detection direction, gain of the radar antenna and the intelligent reflecting surface, path transmission loss, channel state information between the intelligent reflecting surface near the radar and the radar receiving array and the like, the radar signal processor calculates and obtains the phase shift amount of each array element of the intelligent reflecting surface near the radar, and the radar carries out corresponding phase shift optimization control on each array element of the intelligent reflecting surface near the radar through the intelligent reflecting surface controller.
In order to maximise the signal-to-noise ratio of the received signal, i.e.
Figure BDA0003390955510000132
Maximization, required for the duration of echo signal reception
Figure BDA0003390955510000133
Expression is carried out on phase shift quantity matrix psi of intelligent reflecting surface near radar1，rIs optimized to meet
Figure BDA0003390955510000134
And (4) maximizing. The phase shift quantity matrix psi of the intelligent reflecting surface near the radar can be processed by a coordinate descent method or a convex optimization method1，rAnd (6) carrying out optimization solution.
Step S4: in the echo signal receiving stage, according to a target detection direction, the gain of the radar communication integrated base station antenna and the intelligent reflecting surface, the path transmission loss, the channel state information between the intelligent reflecting surface near the radar communication integrated base station and the like, the radar signal processor calculates and obtains the phase shift amount of each array element of the intelligent reflecting surface near the radar communication integrated base station, and the radar carries out corresponding phase shift optimization control on each array element of the intelligent reflecting surface near the radar communication integrated base station through the intelligent reflecting surface controller.
In order to maximise the signal-to-noise ratio of the received signal, i.e.
Figure BDA0003390955510000141
Maximization, required for the duration of echo signal reception
Figure BDA0003390955510000142
Phase shift quantity matrix psi of intelligent reflecting surface near radar communication integrated base station in expression2，rIs optimized to meet
Figure BDA0003390955510000143
And (4) maximizing. The phase shift quantity matrix psi of the intelligent reflecting surface near the radar communication integrated base station can be processed by a coordinate descent method or a convex optimization method2，rAnd (6) carrying out optimization solution.
Step S5: and the radar communication integrated base station transmits the received signal to the MIMO radar for cooperative processing, and target detection is carried out. If the detection statistic is larger than the threshold value, a target exists at the distance; otherwise, there is no target at that distance.
According to the Neyman-Pearson criterion, the detection statistic T is:
Figure BDA0003390955510000144
wherein δ is a threshold determined according to the false alarm rate; h0Indicating that there is no target at that distance; h1Indicating that there is a target at that distance; | x | non-conducting phosphor2Representing the square of the 2 norm of x.
To further illustrate the effect of the invention, a received signal x using only MIMO radar is given in fig. 31And the signal-to-noise ratio gain during target detection is carried out. By simultaneously utilizing the communication signals of the radar signal and radar communication integrated base station, arranging the intelligent reflecting surfaces near the radar communication integrated base station and the radar and carrying out corresponding optimization control, the signal-to-noise ratio of the received signals of the radar can be obviously improved. If the received signals x of the radar communication integrated base station are used simultaneously2The target detection performance will be further improved. "phase 2 bit quantization" and "phase continuous quantization" in fig. 3 indicate the quantization accuracy of the phase shift amount of each array element of the intelligent reflection surface, and "phase 2 bit quantization"means that the calculated phase shift amount is uniformly quantized to one of 4 values between 0 and 2 pi; "phase continuous quantization" means directly using the calculated phase shift quantity. Therefore, quantification of the phase shift amount of the intelligent reflecting surface brings certain performance loss.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (7)

1. An intelligent reflector assisted radar communication cooperative target detection method is characterized by comprising the following steps:
step S1: in the signal transmitting stage, according to the target detection direction, the gain of the radar antenna and the intelligent reflecting surface, the path transmission loss and the channel state information between the intelligent reflecting surface near the radar and the radar receiving array, the radar signal processor calculates and obtains the optimized phase shift amount of each array element of the intelligent reflecting surface near the radar, and the radar optimally controls the phase shift amount of each array element of the intelligent reflecting surface near the radar through the intelligent reflecting surface controller.
Step S2: in the signal transmitting stage, according to a target detection direction, the gain of an antenna and an intelligent reflecting surface of the radar communication integrated base station, path transmission loss and channel state information between the intelligent reflecting surface near the radar communication integrated base station and the radar communication integrated base station, a radar signal processor calculates and obtains the optimized phase shift amount of each array element of the intelligent reflecting surface near the radar communication integrated base station, and the radar performs corresponding phase shift optimization control on each array element of the intelligent reflecting surface near the radar communication integrated base station through an intelligent reflecting surface controller;
step S3: in the echo signal receiving stage, according to a target detection direction, gain of a radar antenna and an intelligent reflecting surface, path transmission loss and channel state information between the intelligent reflecting surface near the radar and a radar receiving array, a radar signal processor calculates and obtains a phase shift amount of each array element of the intelligent reflecting surface near the radar, and the radar carries out corresponding phase shift optimization control on each array element of the intelligent reflecting surface near the radar through an intelligent reflecting surface controller;
step S4: in the echo signal receiving stage, according to a target detection direction, the gain of an antenna and an intelligent reflecting surface of the radar communication integrated base station, path transmission loss and channel state information between the intelligent reflecting surface near the radar communication integrated base station and the radar communication integrated base station, a radar signal processor calculates and obtains the phase shift amount of each array element of the intelligent reflecting surface near the radar communication integrated base station, and the radar carries out corresponding phase shift optimization control on each array element of the intelligent reflecting surface near the radar communication integrated base station through an intelligent reflecting surface controller;
step S5: the radar communication integrated base station transmits the received signal to an MIMO radar for cooperative processing, and target detection is carried out; if the detection statistic is larger than the threshold value, a target exists at the distance; otherwise, there is no target at that distance.
2. The method for detecting radar communication cooperative targets assisted by intelligent reflecting surfaces according to claim 1, wherein the step S1 specifically comprises:
considering a narrow-band centralized MIMO radar system, the radar array is equivalent to a linear array, and N antennas are arranged according to a half-wavelength interval; equivalently installing a single antenna on the radar communication integrated base station; the intelligent reflecting surface near the radar and the intelligent reflecting surface near the radar communication integrated base station are equivalent to a linear array, and M are respectively arranged according to the half-wavelength interval1And M2A reflection array element;
assuming that the target is positioned at an angle theta with the normal direction of the radar array1At a distance of (2), the radar channel to the target is
Figure FDA0003390955500000021
Is shown as
Figure FDA0003390955500000022
Wherein
Figure FDA0003390955500000023
As a transmit steering vector of the radar array, theta1Is the normal included angle between the target and the radar array; g1Due to antenna gain, fading and phase shift caused by path transmission;
the channel from the radar to the target through the intelligent reflecting surface nearby is
Figure FDA0003390955500000024
Is shown as
Figure FDA0003390955500000025
Wherein
Figure FDA0003390955500000026
Is a guide vector of an intelligent reflecting surface near the radar, theta4The normal included angle between the target and the intelligent reflecting surface is set; g2The method is characterized in that the method comprises the following steps of (1) fading and phase shift caused by radar array gain, intelligent reflecting surface gain and path transmission;
Figure FDA0003390955500000027
is a diagonal matrix, the nth diagonal element of which is the phase shift quantity of the reflection array element n of the intelligent reflection surface
Figure FDA0003390955500000028
Elements of construction
Figure FDA0003390955500000029
Figure FDA00033909555000000210
Is a channel matrix between the radar and the intelligent reflecting surface;
the channel from the radar communication integrated base station to the target is h3Is shown as
h3＝g3，
Wherein g is3The method comprises the steps of representing fading and phase shift caused by antenna gain and path transmission of the radar communication integrated base station;
the channel from the radar communication integrated base station to the target through the adjacent intelligent reflecting surface is h4Is shown as
Figure FDA0003390955500000031
Wherein
Figure FDA0003390955500000032
Is a guide vector of a smart reflecting surface near a radar communication integrated base station'4The normal included angle between the target and the intelligent reflecting surface is set; g4The antenna gain, the intelligent reflecting surface gain and the fading and phase shift caused by path transmission of the radar communication integrated base station are obtained;
Figure FDA0003390955500000033
is a diagonal matrix, the nth diagonal element of the diagonal matrix is the phase shift quantity of the array element n reflected by the intelligent reflecting surface
Figure FDA0003390955500000034
Elements of construction
Figure FDA0003390955500000035
Figure FDA0003390955500000036
Is a channel matrix between the radar and the intelligent reflecting surface;
when the target echo signal is received, the target-to-radar channel is
Figure FDA0003390955500000037
Is shown as
Figure FDA0003390955500000038
Wherein
Figure FDA0003390955500000039
A receiving steering vector of the radar array;
Figure FDA00033909555000000310
the antenna gain, the intelligent reflecting surface gain and the fading and phase shift caused by path transmission of the radar are adopted;
the channel from the target to the radar through the intelligent reflecting surface is
Figure FDA00033909555000000311
Is shown as
Figure FDA00033909555000000312
Wherein
Figure FDA00033909555000000313
When receiving echo, the antenna gain of radar, the gain of intelligent reflecting surface and the fading and phase shift caused by path transmission;
Figure FDA00033909555000000314
receiving a steering vector of a target echo for the intelligent reflecting surface;
Figure FDA00033909555000000315
is a diagonal matrix, the nth diagonal element of which is the phase shift amount of the reflection array element n when receiving the echo
Figure FDA00033909555000000316
Elements of construction
Figure FDA00033909555000000317
Figure FDA00033909555000000318
A channel matrix between the intelligent reflecting surface and the radar;
when the target echo signal is received, the channel from the target to the radar communication integrated base station is
Figure FDA00033909555000000319
Is shown as
Figure FDA00033909555000000320
Wherein
Figure FDA00033909555000000321
The method comprises the steps of representing fading and phase shift caused by antenna gain and path transmission of the radar communication integrated base station;
the target passes through the intelligent reflecting surface to reach the radar communication integrated base station
Figure FDA00033909555000000322
Is shown as
Figure FDA0003390955500000041
Wherein
Figure FDA0003390955500000042
In order to receive the echo, the antenna gain, the intelligent reflecting surface gain and the fading and phase shift caused by path transmission of the radar communication integrated base station;
Figure FDA0003390955500000043
receiving a steering vector of a target echo for the intelligent reflecting surface;
Figure FDA0003390955500000044
is a diagonal matrix, the nth diagonal element of which is the phase shift amount of the reflection array element n when receiving the echo
Figure FDA0003390955500000045
Elements of construction
Figure FDA0003390955500000046
Figure FDA0003390955500000047
A channel matrix between the intelligent reflecting surface and the radar;
signals transmitted by the radar and radar communication integrated base station are assumed to be orthogonal to each other and are respectively expressed as
Figure FDA0003390955500000048
And
Figure FDA0003390955500000049
l is the length of the signal after sampling and
Figure FDA00033909555000000410
Figure FDA00033909555000000411
INis an N-dimensional unit matrix; assuming that the transmitting signals of the radar and radar communication integrated base station reach the target distance at the same time, and the radar and radar communication integrated base station have the information S of the transmitting signalsraAnd sbs(ii) a The signals received by the MIMO radar are represented as
Figure FDA00033909555000000412
Wherein
Figure FDA00033909555000000413
Is a noise matrix; praIs the transmission power of the radar; pbsIs the transmit power of the base station; alpha is alpharaAnd alphabsThe reflection sectional area of the target relative to the radar and radar communication integrated base station;
the received signal passes through and SraAnd sbsAfter matched filtering, is represented as
Figure FDA00033909555000000414
Wherein
Figure FDA00033909555000000415
The matrix is obtained after Gaussian noise is subjected to matching filtering;
matrix X of received signals1Vectorization is expressed as
Figure FDA00033909555000000416
Wherein h is12＝h1+h2，h34＝h3+h4Wherein vec (X) denotes subjecting X to a vectorization operation,
Figure FDA00033909555000000417
represents the Kronecker product;
the signal received by the radar communication integrated base station is represented as
Figure FDA00033909555000000418
Wherein
Figure FDA00033909555000000419
Is a noise matrix;
the signal received by the radar communication integrated base station passes through the S-channelraAnd sbsAfter matched filtering, is represented as
Figure FDA0003390955500000051
Wherein
Figure FDA0003390955500000052
The matrix is obtained after Gaussian noise is subjected to matching filtering;
matrix X of received signals2Vectorization is expressed as
Figure FDA0003390955500000053
X is to be1And x2Are combined into a vector x of
Figure FDA0003390955500000054
Wherein
Figure FDA0003390955500000055
In order to maximise the signal-to-noise ratio of the received signal, i.e.
Figure FDA0003390955500000056
Maximization, where | · |. non-calculation2Represents the square of the 2 norm; in order to maximize the signal-to-noise ratio of the received signal, it is first necessary to aim at the signal transmission period, h12Expression is carried out on phase shift quantity matrix psi of intelligent reflecting surface near radar1，tIs optimized to meet
Figure FDA0003390955500000057
Maximization; phase shift quantity matrix psi of intelligent reflecting surface near radar by coordinate descent method or convex optimization method1，tCarrying out optimization solution to obtain the phase shift quantity of each array element of the intelligent reflecting surface, and carrying out corresponding operation on the intelligent reflecting surface according to the phase shift quantityThe phase shift.
3. The method for detecting radar communication cooperative targets assisted by intelligent reflecting surfaces according to claim 1 or 2, wherein the step S2 specifically comprises:
in order to maximise the signal-to-noise ratio of the received signal, i.e.
Figure FDA0003390955500000058
Maximization, required for the signal transmission period, over h34Phase shift quantity matrix psi of intelligent reflecting surface near radar communication integrated base station in expression2，tOptimizing to satisfy Pbsαbsh34||2Maximization; phase shift quantity matrix psi of intelligent reflecting surface near radar communication integrated base station by coordinate descent method or convex optimization method2，tAnd (6) carrying out optimization solution.
4. The method for detecting radar communication cooperative targets assisted by intelligent reflecting surfaces according to claim 1 or 2, wherein the step S3 specifically comprises:
in order to maximise the signal-to-noise ratio of the received signal, i.e.
Figure FDA0003390955500000061
Maximization, required for the duration of echo signal reception
Figure FDA0003390955500000062
Expression is carried out on phase shift quantity matrix psi of intelligent reflecting surface near radar1，rIs optimized to meet
Figure FDA0003390955500000063
Maximization; phase shift quantity matrix psi of intelligent reflecting surface near radar by coordinate descent method or convex optimization method1，rAnd (6) carrying out optimization solution.
5. The method for detecting radar communication cooperative targets assisted by intelligent reflecting surfaces according to claim 1 or 2, wherein the step S4 specifically comprises:
in order to maximise the signal-to-noise ratio of the received signal, i.e.
Figure FDA0003390955500000064
Maximization, required for the duration of echo signal reception
Figure FDA0003390955500000065
Phase shift quantity matrix psi of intelligent reflecting surface near radar communication integrated base station in expression2，rIs optimized to meet
Figure FDA0003390955500000068
Maximization; phase shift quantity matrix psi of intelligent reflecting surface near radar communication integrated base station by coordinate descent method or convex optimization method2，rAnd (6) carrying out optimization solution.
6. The method for detecting radar communication cooperative targets assisted by intelligent reflecting surfaces according to claim 1 or 2, wherein the detection statistic T in the step S5 is specifically:
Figure FDA0003390955500000067
wherein δ is a threshold determined according to the false alarm rate; h0Indicating that there is no target at that distance; h1Indicating that there is a target at that distance; | x | non-conducting phosphor2Representing the square of the 2 norm of x.
7. An electronic device, comprising: at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the intelligent reflecting surface assisted radar communication cooperative target detection method of any one of claims 1 to 6.
CN202111474150.2A 2021-12-03 2021-12-03 Intelligent reflecting surface assisted radar communication cooperative target detection method and electronic equipment Pending CN114185019A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115499073A (en) * 2022-08-24 2022-12-20 南京邮电大学 Multi-intelligent reflection surface assisted radar sensing and communication coexistence method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115499073A (en) * 2022-08-24 2022-12-20 南京邮电大学 Multi-intelligent reflection surface assisted radar sensing and communication coexistence method

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