A communication positioning integration method for maritime communication

Abstract

The application discloses a communication positioning integrated method for maritime communication and belongs to the field of maritime wireless communication. The method provided by the application uses ground base stations and low-orbit satellites to provide communication services for near-shore user groups and far-shore user groups respectively, and completes wide-area coverage of sea areas. The ground base stations and the low-orbit satellites transmit communication positioning dual-function signals, sea user terminals receive and decode data signals, the ground base stations and the low-orbit satellites receive reflection signals containing target position information from the sea user terminals respectively, and then transmit the reflection signals to the ground base stations through a space-ground link to perform data fusion and target position estimation, so that the sea user is provided with information communication services and the target is subjected to position perception. The application provides an effective communication positioning integrated method for a maritime communication system based on a space-ground heterogeneous network.

Description

Technical Field

[0001] This invention belongs to the field of maritime wireless communication technology, and particularly relates to an integrated communication and positioning method for maritime communication. Background Technology

[0002] With the rapid development of wireless communication, maritime activities such as marine tourism, aquaculture, and marine mineral exploration have grown rapidly in recent years, leading to an increase in maritime users and a growing demand for high-speed, reliable maritime communication. For example, all ships at sea require navigation information and operational data to ensure the safety of their voyages, while passengers and crew also need multimedia communication services. Therefore, building a broadband maritime communication network oriented towards the maritime Internet of Things (IoT) is of great significance for maritime transportation, maritime production, and maritime emergency rescue.

[0003] Current maritime wireless communication systems are mostly based on shore-based base stations and single satellite systems, and their information communication and location awareness functions are also independent. This limits the functionality, cost, and efficiency of current maritime communication systems. To address this issue, a new approach for integrated space-ground networks in maritime communication involves the collaborative operation of ground base station systems and maritime satellite systems. This improves the accuracy and reliability of information communication and location awareness, enabling more efficient data transmission and positioning services. This method offers advantages such as wide coverage, high transmission speed, and strong anti-interference capabilities, and represents an important direction for future maritime communication systems.

[0004] Therefore, providing an effective integrated design method for communication and positioning in maritime communication based on heterogeneous satellite-ground networks is of great significance for the construction of smart ocean. Summary of the Invention

[0005] The purpose of this invention is to meet the growing communication and positioning needs at sea, solve the problems of high cost, high energy consumption, insufficient coverage and performance faced by traditional independent information communication and location awareness systems, and provide an integrated communication and positioning method for maritime communication.

[0006] The specific technical solution adopted in this invention is as follows:

[0007] This invention provides an integrated communication and positioning method for maritime communications, comprising the following steps:

[0008] S1. Construct a maritime communication system comprising a ground base station equipped with several antennas and a low-orbit satellite equipped with several antennas; the ground base station serves multiple single-antenna near-shore users, and the low-orbit satellite serves multiple single-antenna far-shore users; the target object is jointly sensed and located through the ground base station and the low-orbit satellite.

[0009] S2. Obtain the downlink channel status information of the ground base station and the low-orbit satellite at the current moment. Based on the downlink channel status information, design corresponding transmission beams for near-shore and far-shore users according to the integrated communication and positioning beam design method.

[0010] S3. Based on the transmission beams designed for near-shore users and the transmission beams designed for far-shore users, the signal construction method is used to obtain the transmission signals corresponding to the ground base station and the low-orbit satellite and transmit them.

[0011] S4. After the near-shore user receives the transmission signal transmitted by the ground base station and the far-shore user receives the transmission signal transmitted by the low-orbit satellite, the near-shore user and the far-shore user decode the required signal respectively; the target object simultaneously receives the transmission signals transmitted by the ground base station and the low-orbit satellite, and the transmission signals received by the target object are used as the corresponding echo signals and reflected back to the ground base station and the low-orbit satellite respectively.

[0012] S5, the ground base station and the low-orbit satellite respectively receive the echo signal reflected by the target object, and perform data processing on the echo signal based on the direct positioning method of the adaptive differential evolution algorithm to obtain the angle information of the target object at the ground base station and the low-orbit satellite, as well as the signal transmission delay information from the ground base station to the target object.

[0013] S6. The ground base station obtains the three-dimensional coordinate position of the target object based on the angle information of the target object at the ground base station, the angle information of the target object at the low-orbit satellite, and the signal transmission delay information.

[0014] Furthermore, the integrated communication and positioning beam design method is as follows:

[0015] a) to maximize the sum rate of near-shore and far-shore users To achieve the design goal, the communication transmission rate of the i-th nearshore user was calculated. Communication transmission rate with the kth remote user Where K1 represents the number of near-shore users, K2 represents the number of near-shore users, and w i v represents the transmit beam designed by the ground base station for the i-th near-shore user. k This represents the transmission beam designed for the k-th distant user by a low-Earth orbit satellite, where H represents the conjugate transpose, and h... 1,i h represents the downlink channel state information of the ground base station for the i-th nearshore user at the current moment. 2,k This represents the downlink channel state information of the low-orbit satellite for the k-th remote user at the current moment. and Let |·| be the variances of the Gaussian noise received by the i-th near-shore user and the k-th far-shore user, respectively. 2Represented as the square of the absolute value;

[0016] b) Transform the design goal into maximization This indicates the communication transmission rate of near-shore users after processing. This indicates the processed remote user rate. The specific transformation steps are as follows:

[0017] b1) Define intermediate variables

[0018] and Where tr(·) represents the trace of the matrix;

[0019] b2) Based on the above intermediate variables, the communication transmission rate of nearshore users is converted into R. 1,i =log2[A i ]-log2[B i The communication transmission rate of remote users is converted into R 2,k =log2[C k ]-log2[D k ], and for log2[B i ] and log2[D k Perform first-order Taylor expansion and successive convex approximation iterations respectively to obtain

[0020] in and For the p≥1th iteration of the successive convex approximation algorithm, W i and V k ;

[0021] c) Calculate the Fisher information matrix for obtaining the location information of the target object from the ground base station. Fisher information matrix for the position information of target objects from low-Earth orbit satellites in θ1 and These are the azimuth and elevation angles from the ground base station to the target, θ2 and θ3, respectively. α1 and α2 represent the azimuth and elevation angles of the low-Earth orbit satellite to the target, respectively. α1 represents the reflection coefficient of the target object to the ground base station, and α2 represents the reflection coefficient of the target object to the low-Earth orbit satellite. The superscript T indicates transpose.

[0022]

[0023]

[0024] in,[·] i,j This represents the element in the i-th row and j-th column of the matrix.

[0025]

[0026] a r (·)and These are the transmit steering vector and receive steering vector of the ground base station, respectively, ξ1=α|h 1,i | 2 ξ2 represents the complex channel gain from the ground base station to the target object, ξ2=α|h 2,k | 2 This represents the complex channel gain from a low-Earth orbit satellite to a target object, and x1(t) represents the complex channel gain from the low-Earth orbit satellite to the target object and then to the ground base station, x2(t) is the transmitted signal from the ground base station to the near-shore user, x2(t) is the transmitted signal from the low-Earth orbit satellite to the far-shore user, α represents the reflection coefficient of the target object, and t represents the time.

[0027] d) Calculate and obtain the Cramerlow lower bound for the position perception of the target object from both ground base stations and low-orbit satellites. and in and η1 and η2 are the Jacobian matrices from the position information vectors η1 and η2 to the coordinate position of the target object, respectively, and p is the coordinate vector of the target object;

[0028] e) Based on the positioning performance constraints, let tr(C1)≤ε1 and tr(C2)≤ε2, where ε1 and ε2 are threshold constants; based on the Schur complement lemma, the positioning performance constraints are transformed into the following positive definite matrices:

[0029]

[0030] U1≥0, tr(U1)≤ε1

[0031] U2≥0, tr(U2)≤ε2,

[0032] U1 and U2 are auxiliary variables;

[0033] f) Solve W using the CVX toolkit i and V k Then, eigenvalue decomposition and vector splitting are performed to obtain the transmission beam w designed by the ground base station for the i-th near-shore user. i The transmission beam v designed for the k-th remote user by low-Earth orbit satellite k .

[0034] Preferably, the value of ε1 is 0.1.

[0035] Preferably, the value of ε2 is 0.1.

[0036] Preferably, U1 and U2 are both arbitrary third-order matrices.

[0037] Furthermore, the steps for obtaining the angle information of the target object at the ground base station and the low-Earth orbit satellite using the direct localization method based on the adaptive differential evolution algorithm are as follows:

[0038] a) Construct an initial population based on the transmit beams designed for near-shore users and the transmit beams designed for far-shore users, with a population size of N. p The population dimension is d rand The maximum number of iterations is G. max The initial mutation factor is F0;

[0039] b) Randomly select three different experimental individuals r1, r2, r3 ≠ i to generate new experimental individuals. Where i represents the individual index and g represents the iteration index. This represents the r1-th experimental individual in the g-th generation of the initial population. Indicates the adaptive variation factor;

[0040] c) Increasing the diversity of the interference parameter vector by introducing a crossover operation, if t1 <C R or d <d rand ,but otherwise Where C R The crossover operator is represented, t1 represents a random number in [0,1], and d represents the number of sequences in the population dimension. This represents the i-th target individual in the g-th generation of the d-th population dimension;

[0041] d1) Obtain the fitness function Where y1 is the reference signal reflected back to the ground base station by the target object, and y2 is the reference signal reflected back to the low-Earth orbit satellite by the target object;

[0042] e1) Based on the greedy criterion, the experimental individual is compared with the target individual in the current population. Then update the individual otherwise like Then update the individual otherwise

[0043] f1) If the maximum number of iterations or the fitness function is reached... During convergence, the current If the angle information of the target object at the ground base station is used, otherwise let g = g + 1, and repeat steps c) to e1); if the maximum number of iterations or the fitness function is reached... During convergence, the current As the angle information of the target object at the low-orbit satellite, otherwise let g = g + 1, and repeat steps c) to e1).

[0044] Furthermore, the steps for obtaining signal transmission delay information from the ground base station to the target object using the direct localization method based on the adaptive differential evolution algorithm are as follows:

[0045] d2) Obtain the fitness function based on steps a) to c).

[0046] e2) Based on the greedy criterion, the experimental individual is compared with the target individual in the current population. Then update the individual otherwise

[0047] f2) If the maximum number of iterations or the fitness function is reached... During convergence, the current As the signal transmission delay information from the ground base station to the target object, otherwise let g = g + 1, and repeat steps c) to e2).

[0048] Preferably, the crossover operator C R The value is 0.7.

[0049] Furthermore, the signal construction method is as follows: the ground base station bases the signal based on the transmitted beam w. i Constructing the transmission signal Where s 1,i For signals with a unit norm Gaussian distribution associated with near-shore user equipment; low-Earth orbit satellites rely on the transmitted beam v k Constructing the transmission signal Where s 2,k The signal is a unit-norm Gaussian distributed signal associated with remote user equipment.

[0050] Furthermore, the echo signals reflected back to the ground base station and the low-orbit satellite by the target object are the product of the transmitted signals of the ground base station and the low-orbit satellite and the channel gain, respectively.

[0051] Compared with the prior art, the present invention has the following advantages:

[0052] This invention proposes an integrated communication and positioning method for maritime communications, addressing the shortcomings of traditional independent ground and satellite systems, as well as the independent information communication and position awareness functions, which result in low system performance and efficiency, low data transmission rates, and high costs. Furthermore, the integrated information communication and position awareness beam and waveform design method and the direct positioning method based on the adaptive differential evolution algorithm proposed in this invention offer advantages such as low complexity and high positioning accuracy. Attached Figure Description

[0053] Figure 1 This is a block diagram of an integrated communication and positioning system for maritime communications.

[0054] Figure 2 This is a performance comparison of maritime users and rates versus iteration counts at different positioning accuracies.

[0055] Figure 3 This is a comparison of the performance of maritime users and rates and positioning accuracy under different numbers of antennas. Detailed Implementation

[0056] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Technical features in the various embodiments of the present invention can be combined accordingly without mutual conflict.

[0057] In a preferred embodiment of the present invention, a communication and positioning integrated method for maritime communications includes the following steps S1 to S6. The specific implementation process of each step is described in detail below.

[0058] S1. Construct a maritime communication system comprising a ground base station equipped with several antennas and a low-orbit satellite equipped with several antennas; the ground base station serves multiple single-antenna near-shore users, and the low-orbit satellite serves multiple single-antenna far-shore users; target objects are sensed and located jointly by the ground base station and the low-orbit satellite.

[0059] It should be noted that, as Figure 1As shown, the maritime communication system operated by the method provided by this invention includes a ground base station equipped with M1 antennas and a low-Earth orbit (LEO) satellite equipped with M2 antennas. The ground base station serves K1 single-antenna nearshore users, and the LEO satellite serves K2 single-antenna offshore users. The ground base station and LEO satellite provide communication services to the nearshore and offshore user groups respectively, achieving wide-area coverage of the sea surface area. The ground base station and LEO satellite jointly sense and locate target objects (denoted as the location target in the figure), which can be islands or ships at sea.

[0060] S2. Obtain the downlink channel status information of the ground base station and the low-orbit satellite at the current moment. Based on the downlink channel status information, design the corresponding transmission beams for near-shore and far-shore users according to the communication and positioning integrated beam design method.

[0061] In this embodiment, the steps of the integrated communication and positioning beam design method are as follows:

[0062] a) to maximize the sum rate of near-shore and far-shore users To achieve the design goal, the communication transmission rate of the i-th nearshore user was calculated. Communication transmission rate with the kth remote user Where w i v represents the transmit beam designed by the ground base station for the i-th near-shore user. k This represents the transmission beam designed for the k-th distant user by a low-Earth orbit satellite, where H represents the conjugate transpose, and h... 1,i h represents the downlink channel state information of the ground base station for the i-th nearshore user at the current moment. 2,k This represents the downlink channel state information of the low-orbit satellite for the k-th remote user at the current moment. and Let |·| be the variances of the Gaussian noise received by the i-th near-shore user and the k-th far-shore user, respectively. 2 Represented as the square of the absolute value;

[0063] b) Transform the design goal into maximization This indicates the communication transmission rate of near-shore users after processing. This indicates the processed remote user rate. The specific transformation steps are as follows:

[0064] b1) Define intermediate variables

[0065] and Where tr(·) represents the trace of the matrix, wm The transmit beam designed for the m-th near-shore user by the ground base station, v n The transmission beam designed for the nth remote user from a low-Earth orbit satellite;

[0066] b2) Based on the above intermediate variables, the communication transmission rate of nearshore users is converted into R. 1,i =log2[A i ]-log2[B i The communication transmission rate of remote users is converted into R 2,k =log2[C k ]-log2[D k ], and for log2[B i ] and log2[D k Perform first-order Taylor expansion and successive convex approximation iterations respectively to obtain

[0067] in and For the p≥1th iteration of the successive convex approximation algorithm, W i and V k ;

[0068] c) Calculate the Fisher information matrix for obtaining the location information of the target object from the ground base station. Fisher information matrix for the position information of target objects from low-Earth orbit satellites in θ1 and These are the azimuth and elevation angles from the ground base station to the target, θ2 and θ3, respectively. Here, α represents the azimuth and elevation angles from the low-Earth orbit satellite to the target, respectively. α is the reflection coefficient of the target object, α1 represents the reflection coefficient of the target object to the ground base station, and α2 represents the reflection coefficient of the target object to the low-Earth orbit satellite. The values ​​of α, α1, and α2 are the same. The subscripts 1 and 2 in α1 and α2 are only used to distinguish the reflection path. The superscript T indicates transpose.

[0069]

[0070] in,[·] i,j This represents the element in the i-th row and j-th column of the matrix.

[0071]

[0072] a r (·)and These are the transmit steering vector and receive steering vector of the ground base station, respectively, ξ1=α|h 1,i |2 ξ2 represents the complex channel gain from the ground base station to the target object, ξ2=α|h 2,k | 2 This represents the complex channel gain from a low-Earth orbit satellite to a target object, and x1(t) represents the complex channel gain from the low-Earth orbit satellite to the target object and then to the ground base station, x2(t) represents the transmitted signal from the ground base station to the near-shore user, and x2(t) represents the transmitted signal from the low-Earth orbit satellite to the far-shore user, where t represents time.

[0073] d) Calculate and obtain the Cramerlow lower bound for the position perception of the target object from both ground base stations and low-orbit satellites. and in and η1 and η2 are the Jacobian matrices from the position information vectors η1 and η2 to the coordinate position of the target object, respectively, and p is the coordinate vector of the target object;

[0074] e) Based on positioning performance limitations, let tr(C1)≤ε1 and tr(C2)≤ε2, where ε1 and ε2 are threshold constants that can be set manually based on experience; ε1 and ε2 are generally taken as 0.1. Auxiliary variables U1 and U2 are introduced; in this embodiment, U1 and U2 can each be selected as any third-order matrix. Since...

[0075] Therefore, based on Schur complement lemma, the positioning performance constraint is transformed into the following positive definite matrix:

[0076]

[0077] U1≥0, tr(U1)≤ε1

[0078] U2≥0, tr(U2)≤ε2;

[0079] f) Solve W using the CVX toolkit i and V k Then, eigenvalue decomposition and vector splitting are performed to obtain the transmission beam w designed by the ground base station for the i-th near-shore user. i The transmission beam v designed for the k-th remote user by low-Earth orbit satellite k .

[0080] S3. Based on the transmission beams designed for near-shore users and the transmission beams designed for far-shore users, the signal construction method is used to obtain the corresponding transmission signals of the ground base station and the low-orbit satellite and transmit them.

[0081] In this embodiment, the signal construction method is as follows: the ground base station uses the transmitted beam w i Constructing the transmission signal Where s1,i For signals with a unit norm Gaussian distribution associated with near-shore user equipment; low-Earth orbit satellites rely on the transmitted beam v k Constructing the transmission signal Where s 2,k The signal is a unit-norm Gaussian distributed signal associated with remote user equipment.

[0082] S4. After the near-shore user receives the transmission signal transmitted by the ground base station and the far-shore user receives the transmission signal transmitted by the low-orbit satellite, the near-shore user and the far-shore user decode the required signals respectively; the target object simultaneously receives the transmission signals transmitted by the ground base station and the low-orbit satellite, and the transmission signals received by the target object are used as the corresponding echo signals and reflected back to the ground base station and the low-orbit satellite respectively.

[0083] It should be noted that near-shore users are subject to interference from low-Earth orbit satellites while receiving signals from terrestrial base stations. Therefore, both near-shore and far-shore users need to decode the received signals. The signals required by near-shore and far-shore users are Gaussian signals with a unit norm distribution, s, which are relevant to the near-shore user equipment. 1,i And the unit norm Gaussian distribution of the signal s associated with remote user equipment 2,k The transmitted signal received by the target object (i.e., the echo signal reflected by the target object) is the product of the transmitted signals transmitted by the ground base station and the low-orbit satellite and the channel gain; the echo signal reflected by the target object received by the ground base station and the low-orbit satellite (i.e., the reflected signal) is the product of the reflected echo signal, the reflection coefficient of the target object, and the channel gain.

[0084] S5, the ground base station, and the low-orbit satellite respectively receive the echo signals reflected by the target object, and process the echo signals using the direct positioning method based on the adaptive differential evolution algorithm to obtain the angle information of the target object at the ground base station and the low-orbit satellite, as well as the signal transmission delay information from the ground base station to the target object.

[0085] In this embodiment, the steps for obtaining the angle information of the target object at the ground base station and the low-orbit satellite using the direct localization method based on the adaptive differential evolution algorithm are as follows:

[0086] a) Construct an initial population based on the transmit beams designed for near-shore users and the transmit beams designed for far-shore users, with a population size of N. p The population dimension is d rand The maximum number of iterations is G. max The initial mutation factor is F0;

[0087] b) Randomly select three different experimental individuals r1, r2, r3 ≠ i to generate new experimental individuals. Where i represents the individual index and g represents the iteration index. This represents the r1-th experimental individual in the g-th generation of the initial population. Indicates the adaptive variation factor;

[0088] c) Increasing the diversity of the interference parameter vector by introducing a crossover operation, if t1 <C R or d <d rand ,but otherwise Where C R The crossover operator is represented, t1 represents a random number in [0,1], and d represents the number of sequences in the population dimension. This represents the i-th target individual in the g-th generation of the d-th population dimension;

[0089] d1) Obtain the fitness function Where y1 is the reference signal reflected back to the ground base station by the target object, and y2 is the reference signal reflected back to the low-Earth orbit satellite by the target object;

[0090] e1) Based on the greedy criterion, the experimental individual is compared with the target individual in the current population. Then update the individual otherwise like Then update the individual otherwise

[0091] f1) If the maximum number of iterations or the fitness function is reached... During convergence, the current If the angle of the target object at the ground base station is used as the information, otherwise let g = g + 1, and repeat steps c) to e1); if the maximum number of iterations or the fitness function is reached... During convergence, the current As the angle information of the target object at the low-orbit satellite, otherwise let g = g + 1, and repeat steps c) to e1).

[0092] It should be noted that in this embodiment, when the fitness function At this time That is Let represent the angle vector of the i-th experimental individual in the initial population at generation g. Based on a greedy criterion, the experimental individual is compared with the target individual in the current population. If... Then update the individual otherwise at this time That is This represents the angle vector of the i-th target individual in the current population at generation g. If the maximum number of iterations or the fitness function is reached... During convergence, the current As the angle information of the target object at the ground base station Similarly, when the fitness function at this time That is Based on the greedy criterion, the experimental individual is compared with the target individual in the current population. If the maximum number of iterations or the fitness function is reached... During convergence, the current As the angle information of the target object at the ground base station

[0093] In this embodiment, the steps for obtaining signal transmission delay information from the ground base station to the target object using the direct positioning method based on the adaptive differential evolution algorithm are as follows:

[0094] a) Construct an initial population based on the transmit beams designed for near-shore users and the transmit beams designed for far-shore users, with a population size of N. p The population dimension is d rand The maximum number of iterations is G. max The initial mutation factor is F0;

[0095] b) Randomly select three different experimental individuals r1, r2, r3 ≠ i to generate new experimental individuals. Where i represents the individual index and g represents the iteration index. This represents the r1-th experimental individual in the g-th generation of the initial population. Indicates the adaptive variation factor;

[0096] c) Increasing the diversity of the interference parameter vector by introducing a crossover operation, if t1 <C R or d <d rand ,but otherwise Where C R The crossover operator is represented, t1 represents a random number in [0,1], and d represents the number of sequences in the population dimension. This represents the i-th target individual in the g-th generation of the d-th population dimension;

[0097] d2) Obtain the fitness function Where y1 is the reference signal reflected back to the ground base station by the target object;

[0098] e2) Based on the greedy criterion, the experimental individual is compared with the target individual in the current population. Then update the individual otherwise

[0099] f2) If the maximum number of iterations or the fitness function is reached... During convergence, the current As the signal transmission delay information from the ground base station to the target object, otherwise let g = g + 1, and repeat steps c) to e2).

[0100] It should be noted that in this embodiment, the actual echo signal y1(t-τ) is obtained, where τ represents the actual time delay information, and the fitness function is obtained as follows: At this time That is This represents the signal transmission delay information of the i-th experimental individual in the initial population at generation g. Based on a greedy criterion, the experimental individual is compared with the target individual in the current population. If the maximum number of iterations or the fitness function is reached... During convergence, the current τ, representing the angle information of the target object at the ground base station max .

[0101] S6. The ground base station uses the angle information of the target object at the ground base station. Angular information of target objects from low-Earth orbit satellites and signal transmission delay information τ max Obtain the three-dimensional coordinates of the target object.

[0102] The computer simulation results of the integrated communication and positioning method for maritime communications provided by this invention are as follows: Figure 2 As shown in the figure, the sum rate of near-shore and far-shore users in the method proposed in this invention gradually increases and then stabilizes with the increase of the number of beamforming algorithm iterations, but decreases with the increase of positioning accuracy. Therefore, the sum rate of near-shore and far-shore users can be maximized while ensuring the target positioning accuracy. Figure 3 As shown in the figure, the sum rate of near-shore and far-shore users gradually increases with the increase of the number of antennas proposed in this invention. This invention provides an effective integrated communication and positioning method for space-ground integrated networks in 6G maritime communication scenarios.

[0103] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A communication and positioning integrated method for maritime communications, characterized in that, Includes the following steps: S1. Construct a maritime communication system comprising a ground base station equipped with several antennas and a low-orbit satellite equipped with several antennas; the ground base station serves multiple single-antenna near-shore users, and the low-orbit satellite serves multiple single-antenna far-shore users; the target object is jointly sensed and located through the ground base station and the low-orbit satellite. S2. Obtain the downlink channel status information of the ground base station and the low-orbit satellite at the current moment. Based on the downlink channel status information, design corresponding transmission beams for near-shore and far-shore users according to the integrated communication and positioning beam design method. S3. Based on the transmission beams designed for near-shore users and the transmission beams designed for far-shore users, the signal construction method is used to obtain the transmission signals corresponding to the ground base station and the low-orbit satellite and transmit them. S4. After the near-shore user receives the transmission signal transmitted by the ground base station and the far-shore user receives the transmission signal transmitted by the low-orbit satellite, the near-shore user and the far-shore user decode the required signal respectively. The target object simultaneously receives transmission signals from both the ground base station and the low-orbit satellite. The transmission signals received by the target object are used as corresponding echo signals and reflected back to the ground base station and the low-orbit satellite, respectively. S5, the ground base station and the low-orbit satellite respectively receive the echo signal reflected by the target object, and perform data processing on the echo signal based on the direct positioning method of the adaptive differential evolution algorithm to obtain the angle information of the target object at the ground base station and the low-orbit satellite, as well as the signal transmission delay information from the ground base station to the target object. S6. The ground base station obtains the three-dimensional coordinate position of the target object based on the angle information of the target object at the ground base station, the angle information of the target object at the low-orbit satellite, and the signal transmission delay information.

2. The integrated communication and positioning method for maritime communication according to claim 1, characterized in that, The integrated communication and positioning beam design method is as follows: a) to maximize the sum rate of near-shore and far-shore users To achieve the design goal, the communication transmission rate of the i-th nearshore user was calculated. Communication transmission rate with the kth remote user Where K1 represents the number of near-shore users, K2 represents the number of near-shore users, and w i v represents the transmit beam designed by the ground base station for the i-th near-shore user. k This represents the transmission beam designed for the k-th distant user by a low-Earth orbit satellite, where H represents the conjugate transpose, and h... 1,i h represents the downlink channel state information of the ground base station for the i-th nearshore user at the current moment. 2,k This represents the downlink channel state information of the low-orbit satellite for the k-th remote user at the current moment. and Let |·| be the variances of the Gaussian noise received by the i-th near-shore user and the k-th far-shore user, respectively. 2 Represented as the square of the absolute value; b) Transform the design goal into maximization This indicates the communication transmission rate of near-shore users after processing. This indicates the processed remote user rate. The specific transformation steps are as follows: b1) Define intermediate variables and Where tr(·) represents the trace of the matrix; b2) Based on the above intermediate variables, the communication transmission rate of nearshore users is converted into R. 1,i =log2[A i ]-log2[B i The communication transmission rate of remote users is converted into R 2,k =log2[C k ]-log2[D k ], and for log2[B i ] and log2[D k Perform first-order Taylor expansion and successive convex approximation iterations respectively to obtain in and For the p≥1th iteration of the successive convex approximation algorithm, W i and V k ; c) Calculate the Fisher information matrix for obtaining the location information of the target object from the ground base station. Fisher information matrix for the position information of target objects from low-Earth orbit satellites in θ1 and These are the azimuth and elevation angles from the ground base station to the target, θ2 and θ3, respectively. α1 and α2 represent the azimuth and elevation angles of the low-Earth orbit satellite to the target, respectively. α1 represents the reflection coefficient of the target object to the ground base station, and α2 represents the reflection coefficient of the target object to the low-Earth orbit satellite. The superscript T indicates transpose. in,[·] i,j This represents the element in the i-th row and j-th column of the matrix. a r (·)and These are the transmit steering vector and receive steering vector of the ground base station, respectively, ξ1=α|h 1,i | 2 ξ2 represents the complex channel gain from the ground base station to the target object, ξ2=α|h 2,k | 2 This represents the complex channel gain from a low-Earth orbit satellite to a target object, and x1(t) represents the complex channel gain from the low-Earth orbit satellite to the target object and then to the ground base station, x2(t) is the transmitted signal from the ground base station to the near-shore user, x2(t) is the transmitted signal from the low-Earth orbit satellite to the far-shore user, α represents the reflection coefficient of the target object, and t represents the time. d) Calculate and obtain the Cramerlow lower bound for the position perception of the target object from both ground base stations and low-orbit satellites. and in and η1 and η2 are the Jacobian matrices from the position information vectors η1 and η2 to the coordinate position of the target object, respectively, and p is the coordinate vector of the target object; e) Based on the positioning performance constraints, let tr(C1)≤ε1 and tr(C2)≤ε2, where ε1 and ε2 are threshold constants; based on the Schur complement lemma, the positioning performance constraints are transformed into the following positive definite matrices: U1≥0, tr(U1)≤ε1 U2≥0, tr(U2)≤ε2, U1 and U2 are auxiliary variables; f) Solve W using the CVX toolkit i and V k Then, eigenvalue decomposition and vector splitting are performed to obtain the transmission beam w designed by the ground base station for the i-th near-shore user. i The transmission beam v designed for the k-th remote user by low-Earth orbit satellite k .

3. The integrated communication and positioning method for maritime communication according to claim 2, characterized in that, The value of ε1 is 0.

1.

4. The integrated communication and positioning method for maritime communication according to claim 2, characterized in that, The value of ε2 is 0.

1.

5. The integrated communication and positioning method for maritime communication according to claim 2, characterized in that, U1 and U2 are arbitrary third-order matrices.

6. The integrated communication and positioning method for maritime communication according to claim 1, characterized in that, The steps for obtaining the angle information of the target object at the ground base station and the low-Earth orbit satellite using the direct localization method based on the adaptive differential evolution algorithm are as follows: a) Construct an initial population based on the transmit beams designed for near-shore users and the transmit beams designed for far-shore users, with a population size of N. p The population dimension is d rand The maximum number of iterations is G. max The initial mutation factor is F0; b) Randomly select three different experimental individuals r1, r2, r3 ≠ i to generate new experimental individuals. Where i represents the individual index and g represents the iteration index. This represents the r1-th experimental individual in the g-th generation of the initial population. Indicates the adaptive variation factor; c) Increasing the diversity of the interference parameter vector by introducing a crossover operation, if t1 <C R or d <d rand ,but otherwise Where C R The crossover operator is represented, t1 represents a random number in [0,1], and d represents the number of sequences in the population dimension. This represents the i-th target individual in the g-th generation of the d-th population dimension; d1) Obtain the fitness function Where y1 is the reference signal reflected back to the ground base station by the target object, and y2 is the reference signal reflected back to the low-Earth orbit satellite by the target object; e1) Based on the greedy criterion, the experimental individual is compared with the target individual in the current population. Then update the individual otherwise like Then update the individual otherwise f1) If the maximum number of iterations or the fitness function is reached... During convergence, the current As the angle information of the target object at the ground base station, otherwise let g = g + 1, and repeat steps c) to e1); If the maximum number of iterations or the fitness function is reached... During convergence, the current As the angle information of the target object at the low-orbit satellite, otherwise let g = g + 1, and repeat steps c) to e1).

7. The integrated communication and positioning method for maritime communication according to claim 6, characterized in that, The steps for obtaining signal transmission delay information from a ground base station to a target object using the direct localization method based on the adaptive differential evolution algorithm are as follows: d2) Obtain the fitness function based on steps a) to c). e2) Based on the greedy criterion, the experimental individual is compared with the target individual in the current population. Then update the individual otherwise f2) If the maximum number of iterations or the fitness function is reached... During convergence, the current As the signal transmission delay information from the ground base station to the target object, otherwise let g = g + 1, and repeat steps c) to e2).

8. The integrated communication and positioning method for maritime communication according to claim 6, characterized in that, The cross operator C R The value is 0.

7.

9. The integrated communication and positioning method for maritime communication according to claim 1, characterized in that, The signal construction method is as follows: the ground base station bases according to the transmitted beam w i Constructing the transmission signal Where s 1,i For signals with a unit norm Gaussian distribution associated with near-shore user equipment; low-Earth orbit satellites rely on the transmitted beam v k Constructing the transmission signal Where s 2,k The signal is a unit-norm Gaussian distributed signal associated with remote user equipment.

10. The integrated communication and positioning method for maritime communication according to claim 1, characterized in that, The echo signals reflected back to the ground base station and the low-orbit satellite by the target object are the products of the transmitted signals of the ground base station and the low-orbit satellite and the channel gain, respectively.

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