Single-satellite direct positioning method based on space-time signal model and related equipment

Abstract

The invention provides a single-satellite direct positioning method based on a space-time signal model and related equipment, and relates to the technical field of passive localization, and the method comprises the steps: building a rotation array model; converting the earth-centered earth-fixed coordinates of the radiation source into station center sight line coordinates by using a coordinate conversion formula; constructing a receiving signal model based on the station center sight line coordinates of the radiation source and the rotating array model; converting the received signal model into a space-time signal model for single-satellite direct positioning; designing a single-satellite direct positioning cost function based on the space-time signal model; obtaining earth-centered earth-fixed coordinates corresponding to latitude and longitude regions where a radiation source may exist, calculating a cost function spectrum value based on the earth-centered earth-fixed coordinates and the single-satellite direct positioning cost function, and performing modulus and normalization processing on the cost function spectrum value; and determining a target position needing to be positioned based on the processed cost function spectrum value. According to the technical scheme, the positioning performance of a single-satellite direct positioning scene is improved.

Description

Technical Field

[0001] The present application relates to the field of passive positioning technology, and in particular to a single-satellite direct positioning method and related equipment based on a space-time signal model. Background Art

[0002] Passive positioning technology has great application value in modern electronic reconnaissance and other fields due to its advantages of anti-reconnaissance and long range. Using a single satellite to directly locate the radiation source has the advantages of low cost and flexible deployment compared to multi-satellite positioning.

[0003] However, the traditional two-step positioning method estimates the target position information by solving the positioning equation established by solving the positioning parameters obtained by measurement and the position information of the radiation source. The traditional single-satellite two-step positioning is mainly based on the positioning technology of direction of arrival estimation (DOA) (see literature: TRINH-HOANG M, VIBERG M, and PESAVENTO M, Partial relaxation approach: A eigenvalue-based DOA estimator framework [J]. IEEE Transaction on SignalProcessing, 2018, 66 (23): 6190-6203, Yuan Xiaokang. Research on phase interferometer direction finding positioning [J]. Shanghai Aerospace, 1999, (3): 1-7.). Its positioning accuracy is limited by the accuracy of positioning parameter estimation. Parameter estimation error will lead to a large cumulative error, resulting in poor final positioning effect.The single-satellite direct positioning methods based on spatial signal models include the MUSIC-DPD method (see reference: ZISKIND I and WAX M. Maximum likelihood localization of multiple sources by alternating projection [J]. IEEE Transactions on Acoustics, Speech, and Signal Processing, 1988, 36 (10): 1553-1560.), the MVDR-DPD method (see reference: TZAFRI L and WEISS A J. High-resolution direct position determination using MVDR [J]. IEEE Transactions on Wireless Communication, 2016, 15 (9): 6449-6461.), the ML-DPD method (see reference: WEISS AJ, AMAR A. Direct position determination of multiple radio signals [J]. EURASIP Journal on Advances in Signal Processing. 2005, 2005 (1): 37-49.), and the U-ST-SDF method (see reference: YIN JX, LIU RR, WANG D et al. Direct positiondetermination based on unitary space-time subspace data fusion[C].2017 9. th International Conference on Wireless Communications and Signal Processing), most of them do not make full use of Doppler information, and their positioning accuracy and resolution are insufficient, so they are not well suited for single-satellite high-precision direct positioning application scenarios. Therefore, the positioning performance of the existing single-satellite direct positioning method based on the spatial signal model needs to be further improved. Summary of the invention

[0004] The embodiments of the present application provide a single-satellite direct positioning method and related equipment based on a space-time signal model to solve the problems that the positioning accuracy of the traditional two-step positioning method is easily affected by parameter estimation errors, and the positioning accuracy and resolution of the single-satellite direct positioning method based on the spatial signal model are insufficient.

[0005] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.

[0006] According to a first aspect of an embodiment of the present application, a single-satellite direct positioning method based on a space-time signal model is provided, comprising:

[0007] Establish a rotating array model;

[0008] The coordinate conversion formula is used to convert the Earth-centered Earth-fixed coordinates of the radiation source into the station-centered line-of-sight coordinates;

[0009] Construct a receiving signal model based on the station center line of sight coordinates of the radiation source and the rotating array model;

[0010] Convert the received signal model into a space-time signal model for single-satellite direct positioning;

[0011] Designing a single-satellite direct positioning cost function based on the space-time signal model;

[0012] Obtaining geocentric earth-fixed coordinates corresponding to the longitude and latitude regions where the radiation source may exist, calculating cost function spectrum values ​​based on the geocentric earth-fixed coordinates and the single-satellite direct positioning cost function, and performing modulus and normalization processing on the cost function spectrum values;

[0013] The target position to be located is determined based on the processed cost function spectrum value.

[0014] In some embodiments of the present application, based on the above solution, the step of establishing a rotating array model includes:

[0015] Establishing the rotation array model based on formula (1);

[0016]

[0017] In formula (1), d0 represents the starting time array, d l represents the lth time slot array, x0 is the reference array element, the distance between two adjacent array elements is d, R rot is the rotation matrix, θ l is the counterclockwise rotation angle of the lth time slot array.

[0018] In some embodiments of the present application, based on the aforementioned scheme, the coordinate conversion formula includes a conversion formula from geodetic coordinates to earth-centered earth-fixed coordinates and a conversion formula from earth-centered earth-fixed coordinates to station-centered line-of-sight coordinates.

[0019] In some embodiments of the present application, based on the aforementioned solution, the receiving signal model is constructed based on the station center line of sight coordinates of the radiation source and the rotating array model, including:

[0020] Assuming that the satellite receives Q radiation source signals from the earth's surface in L time slots, the received signal model is established based on formula (2);

[0021]

[0022] In formula (2), r l (k) represents the kth received signal, β ql represents the channel attenuation, s ql (k) represents the baseband signal sent by the qth radiation source in the lth time slot, is the Doppler shift, where λ is the wavelength, u l =[x l ,y l ,z l ] T and v l They represent the position and velocity of the satellite in the Earth-centered Earth-fixed coordinate system at the lth time slot, T s =1 / f s is the sampling interval, n l (k) is zero-mean complex Gaussian white noise, represents the spatial array response, where p q =[x q,e ,y q,e ,z q,e ] T is the Earth-fixed position coordinate of the qth radiation source, f c is the center frequency, ε m (p q ) represents the phase difference of the qth radiation source signal at array element m relative to the reference array element, ε m (p q ) is expressed as follows:

[0023]

[0024] Among them, x m is the coordinate of the mth array element relative to the reference array element, θ ql =arctan(y q,g / x q,g ) is the incident azimuth, is the incident pitch angle, where x q,g ,y q,g and z q,g are the satellite station line of sight coordinates, θ l Represents the angle between the array and the positive direction of the satellite platform's x-axis; where l = 1, 2, ..., L, q = 1, 2, ..., Q.

[0025] In some embodiments of the present application, based on the aforementioned solution, the designing of a single-satellite direct positioning cost function based on the space-time signal model includes:

[0026] Calculating a covariance matrix of the space-time received signal;

[0027] Performing forward and backward smoothing on the covariance matrix;

[0028] Divide the processed covariance matrix into D×D block matrices of the same size, where D is the number of snapshots in a segment;

[0029] Perform Toeplitz matrix adjustment on all block matrices separately;

[0030] Perform unitary transformation on the adjusted block matrix to obtain a real-valued covariance matrix;

[0031] Performing eigenvalue decomposition on the real-valued covariance matrix;

[0032] The single-star direct positioning cost function is constructed based on the decomposition result.

[0033] In some embodiments of the present application, based on the above scheme, the obtaining of the geocentric earth-fixed coordinates corresponding to the longitude and latitude area where the radiation source may exist, and the calculation of the cost function spectrum value based on the geocentric earth-fixed coordinates and the single-satellite direct positioning cost function include:

[0034] A set of grid points is set for the latitude and longitude areas where the radiation source may exist in the geodetic coordinate system, and a set of corresponding geocentric earth-fixed coordinates in the geocentric earth-fixed coordinate system is obtained through the coordinate system conversion formula;

[0035] Based on the corresponding earth-centered earth-fixed coordinates in the earth-centered earth-fixed coordinate system and the single-satellite direct positioning cost function, a cost function spectrum value is calculated.

[0036] In some embodiments of the present application, based on the aforementioned solution, determining the target position to be located based on the processed cost function spectrum value includes:

[0037] Setting a threshold of the cost function spectrum value, and removing the cost function spectrum values ​​below the threshold;

[0038] The conventional maximum value method is used to calculate the maximum values ​​in the cost function spectrum value, and the geodetic coordinates of the corresponding grid points are output;

[0039] The target position is determined based on the geodetic coordinates.

[0040] According to a second aspect of an embodiment of the present application, a single-satellite direct positioning device based on a space-time signal model is provided, comprising:

[0041] A first establishing unit is used to establish a rotating array model;

[0042] A first conversion unit is used to convert the Earth-centered Earth-fixed coordinates of the radiation source into the station-centered line-of-sight coordinates using a coordinate conversion formula;

[0043] The second establishing unit is used to construct a receiving signal model based on the station center line of sight coordinates of the radiation source and the rotating array model;

[0044] A second conversion unit, used for converting the received signal model into a space-time signal model for single-satellite direct positioning;

[0045] A design unit, used for designing a single-satellite direct positioning cost function based on the space-time signal model;

[0046] A calculation unit, used for obtaining the geocentric earth-fixed coordinates corresponding to the longitude and latitude area where the radiation source may exist, and calculating the cost function spectrum value based on the geocentric earth-fixed coordinates and the single-satellite direct positioning cost function;

[0047] A processing unit, used for performing modulo and normalization processing on the cost function spectrum value;

[0048] The determination unit is used to determine the target position to be located based on the processed cost function spectrum value.

[0049] According to a third aspect of an embodiment of the present application, a computer-readable storage medium is provided, on which computer instructions are stored. When the computer instructions are executed on a computer, the computer executes the method according to the first aspect.

[0050] According to a fourth aspect of the embodiments of the present application, there is provided an electronic device, including a memory and a processor;

[0051] The memory is used to store computer instructions;

[0052] The processor is used to call the computer instructions stored in the memory so that the electronic device executes the method as described in the first aspect.

[0053] The technical solution of the present application first establishes a receiving signal model and an array model, then derives a space-time signal model for direct positioning of a single satellite, then designs a cost function for direct positioning of a single satellite based on the space-time signal model, and finally obtains the position estimation results of multiple radiation sources through grid search and maximum search. The present invention divides the covariance of the space-time receiving signal matrix into blocks, and then performs Toeplitz matrix adjustment on the above-mentioned block matrix respectively, thereby reducing the influence of noise on the accuracy of eigenvalue decomposition of the covariance matrix and improving the accuracy of radiation source positioning.

[0054] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0056] Figure 1 A schematic diagram of a flow chart of a single-satellite direct positioning method based on a space-time signal model according to an embodiment of the present application is shown;

[0057] Figure 2 A schematic diagram of a receiving signal model according to an embodiment of the present application is shown;

[0058] Figure 3 A schematic diagram showing satellite positions and real positions of radiation sources in each time slot according to an embodiment of the present application is shown;

[0059] Figure 4 A two-dimensional positioning effect diagram according to an embodiment of the present application is shown;

[0060] Figure 5 The relationship between the positioning root mean square error and the signal-to-noise ratio according to an embodiment of the present application is shown in FIG.

[0061] Figure 6 A block diagram of a single-satellite direct positioning device based on a space-time signal model according to an embodiment of the present application is shown;

[0062] Figure 7 A block diagram of an electronic device according to an embodiment of the present application is shown;

[0063] Figure 8 A schematic diagram of the structure of a computer system suitable for implementing an electronic device of an embodiment of the present application is shown. DETAILED DESCRIPTION

[0064] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more comprehensive and complete and fully convey the concept of the example embodiments to those skilled in the art.

[0065] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0066] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0067] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0068] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the objects used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those shown or described.

[0069] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0070] Some embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0071] See also Figure 1 , shows a flow chart of a single-satellite direct positioning method based on a space-time signal model according to an embodiment of the present application.

[0072] like Figure 1As shown, a single-satellite direct positioning method based on a space-time signal model is demonstrated. The method aims to improve the positioning performance of a single-satellite direct positioning scenario, and specifically includes steps S100 to S700.

[0073] Step S100, establishing a rotation array model.

[0074] In some feasible embodiments, based on the above solution, the specific process of establishing the rotation array model is as follows:

[0075] The satellite carries a uniform linear array with M elements and a rotation speed of The spacing between adjacent array elements is d = λ / 2, where λ = c / f c is the wavelength of the signal, then the rotation array model is as follows:

[0076]

[0077] Among them, d0 represents the starting time array, d l represents the lth time slot array, R rot is the rotation matrix, θ l = w·t l is the counterclockwise rotation angle of the lth time slot array, where t l is the time of the lth time slot relative to the starting time.

[0078] The calculation of d0 is as follows:

[0079] d0=[-x (m-1) / 2 ,-x (M-1) / 2-1 ,…,x0,…,x (M-1) / 2-1 ,x (M-1) / 2 ]; (2)

[0080] x0 is the reference array element, and the distance between two adjacent array elements is d.

[0081] Continue to refer Figure 1 , step S200, using a coordinate conversion formula to convert the Earth-centered Earth-fixed coordinates of the radiation source into station-centered line-of-sight coordinates.

[0082] In some feasible embodiments, based on the above scheme, the coordinate conversion formula includes a conversion formula from geodetic coordinates to geocentric earth-fixed coordinates, and a conversion formula from geocentric earth-fixed coordinates to station-centered line-of-sight coordinates.

[0083] Among them, the conversion formula from geodetic coordinates to earth-centered earth-fixed coordinates is:

[0084]

[0085] Where x, y and z represent the Earth-fixed coordinates, B0 represents the latitude, L0 represents the longitude, H0 represents the altitude, γ represents the radius of curvature of the circle, r e represents the Earth's semi-major axis, e 2 represents the first eccentricity squared.

[0086] The conversion formula from Earth-centered Earth-fixed coordinates to station-centered line-of-sight coordinates is:

[0087]

[0088] Among them, L sat and B sat Respectively represent the satellite geodetic longitude and geodetic latitude, x l ,y l and z l are the Earth-centered, Earth-fixed coordinates of the satellite.

[0089] Continue to refer Figure 1 , step S300, constructing a receiving signal model based on the station center line of sight coordinates of the radiation source and the rotating array model.

[0090] In some feasible embodiments, based on the above solution, the process of establishing the received signal model is as follows:

[0091] Assume that the satellite receives Q radiation source signals from the earth's surface in L time slots, see Appendix Figure 2 The satellite carries an array with M array elements, and the distance between adjacent array elements is d. The signal received by the satellite in the lth time slot can be expressed as follows:

[0092]

[0093] Among them, r l (k) represents the kth received signal, β ql represents the channel attenuation, s ql (k) represents the baseband signal sent by the qth radiation source in the lth time slot, is the Doppler shift, where λ is the wavelength, u l =[x l ,y l ,z l ] T and v l T represents the position and velocity of the satellite in the Earth-centered Earth-fixed coordinate system in the lth time slot. s =1 / f s is the sampling interval, n l (k) is zero-mean complex Gaussian white noise, represents the spatial array response, where p q =[x q,e ,y q,e ,zq,e ] T is the Earth-fixed position coordinate of the qth radiation source, f c is the center frequency, ε m (p q ) represents the phase difference of the qth radiation source signal at array element m relative to the reference array element, and the expression is as follows:

[0094]

[0095] Among them, x m is the coordinate of the mth array element relative to the reference array element, θ ql =arctan(y q,g / x q,g ) is the incident azimuth, is the incident pitch angle, where x q,g ,y q,g and z q,g are the satellite station line of sight coordinates, θ l Indicates the angle between the array and the positive x-axis of the satellite platform.

[0096] Continue to refer Figure 1 , step S400, converting the received signal model into a space-time signal model for single-satellite direct positioning.

[0097] In some feasible embodiments, based on the above scheme, the specific process of converting the received signal model into the space-time signal model of single-satellite direct positioning is as follows:

[0098] Assuming that the satellite samples K snapshots in each time slot, and every D snapshots are divided into one segment, which is divided into N segments in total, the nth segment received data of the lth time slot can be expressed as:

[0099]

[0100] in, represents a space-time signal model;

[0101]

[0102] Among them, b l (p q ) is the time domain manifold vector, Represents the Kronecker product operation.

[0103] Continue to refer Figure 1 , step S500, designing a single-satellite direct positioning cost function based on the space-time signal model.

[0104] In some feasible embodiments, based on the above scheme, the design process of the single-satellite direct positioning cost function is as follows:

[0105] S501: Calculate the covariance matrix of the space-time received signal as follows:

[0106]

[0107] S502: The forward and backward smoothing of the covariance matrix is ​​as follows:

[0108]

[0109] Wherein, J represents a swap matrix, the elements on the sub-diagonal of the matrix are 1, and the remaining elements are 0.

[0110] S503: Divide the covariance matrix into D×D block matrices of the same size:

[0111]

[0112] Among them, R dd ∈C M×M ,d=1~D, D is the number of snapshots in a segment.

[0113] S504: For all block matrices R dd ∈C M×M , d=1~D respectively adjust the Toeplitz matrix as follows:

[0114]

[0115] in, represents the mth row element parallel to the main diagonal in the adjusted matrix, r i,j Represents the original block matrix R dd The element at row i and column j in .

[0116] S505: Perform unitary transformation as follows:

[0117]

[0118] in,

[0119]

[0120] in, is the covariance matrix adjusted in step S504, S is the sampling matrix, is the real-valued covariance matrix obtained after the unitary transformation.

[0121] S506: Perform eigenvalue decomposition on the real-valued covariance matrix as follows:

[0122]

[0123] in, yes The diagonal matrix composed of the first Q larger eigenvalues, for The first Q larger eigenvalues ​​correspond to the signal subspace of the eigenvectors, for The remaining smaller DM-Q eigenvalues ​​correspond to the noise subspace of the eigenvector.

[0124] S507: Construct a single-satellite direct positioning cost function as follows:

[0125]

[0126] Where p is the position vector in the solution space. represents the space-time manifold vector, for The generalized inverse of .

[0127] Continue to refer Figure 1 , step S600, obtaining the geocentric earth-fixed coordinates corresponding to the longitude and latitude area where the radiation source may exist, calculating the cost function spectrum value based on the geocentric earth-fixed coordinates and the single-satellite direct positioning cost function, and performing modulus and normalization processing on the cost function spectrum value.

[0128] Specifically, a set of grid points is set for the latitude and longitude areas where the radiation source may exist in the geodetic coordinate system, and a corresponding set of coordinates in the Earth-centered Earth-fixed coordinate system is obtained through a coordinate system conversion formula.

[0129] Set a set of n B ×n L Grid points g ij =[B i ,L j ,H0] T ,i=1,2,…,n B , j=1,2,…,n L , the grid spacing is 0.05°. The corresponding set of coordinates p in the Earth-centered Earth-fixed coordinate system is obtained through the coordinate system conversion formula ij =[x ij ,y ij ,z ij ] T as follows:

[0130]

[0131] Substitute the above set of coordinates into the above-mentioned single-star direct positioning cost function to obtain a set of cost function spectrum values, and then modulus and normalize the set of spectrum values.

[0132] The above set of coordinates p ij =[x ij ,yij ,z ij ] T Substitute the single-star direct positioning cost function in S507 to obtain a set of cost function spectrum values:

[0133]

[0134] Finally, the above spectrum values ​​are modulo and normalized to obtain:

[0135]

[0136] Continue to refer Figure 1 , step S700, determining the target position to be located based on the processed cost function spectrum value.

[0137] In some feasible embodiments, based on the above solution, determining the target position to be located based on the processed cost function spectrum value includes:

[0138] The threshold of the cost function spectrum value is set, and its value range is (0, 1). In this embodiment, it is set to 0.01, and the spectrum values ​​smaller than the threshold factor are set to zero.

[0139] The cost function spectrum value f is calculated using the conventional maximum value method p Each maximum value in , and output the geodetic coordinates of the corresponding grid points;

[0140] The target position is determined based on the geodetic coordinates.

[0141] It can be understood that the output geodetic coordinates are the target positions estimated by this method. If the number of output coordinates is greater than Q, Q coordinates with larger spectral values ​​are retained.

[0142] In summary, this technical solution first establishes a receiving signal model and an array model, then derives a space-time signal model for single-star direct positioning, then designs a single-star direct positioning cost function based on the space-time signal model, and finally obtains the position estimation results of multiple radiation sources through grid search and maximum search.

[0143] This technical solution divides the space-time received signal matrix covariance into blocks and then performs Toeplitz matrix adjustment on the block matrices respectively, thereby reducing the influence of noise on the accuracy of eigenvalue decomposition of the covariance matrix and improving the accuracy of radiation source positioning.

[0144] The technical solution utilizes the unitary transformation technology to transform the adjusted covariance matrix to obtain a real-valued covariance matrix, and performs eigenvalue decomposition on the real-valued covariance matrix, thereby effectively reducing the complexity of the eigenvalue decomposition.

[0145] This technical solution constructs a single-satellite direct positioning cost function based on a space-time signal model by using the signal subspace and noise subspace obtained by decomposing the eigenvalue of the real-valued covariance matrix. The cost function includes a numerator and a denominator, and the numerator and denominator are designed using the signal subspace and the noise subspace respectively. When the grid search position is the real position of the radiation source, the modulus of the numerator reaches the maximum and the modulus of the denominator reaches the minimum; when the grid search position is other positions, the modulus of the numerator is small and the modulus of the denominator reaches a large value; therefore, the positioning accuracy and positioning resolution in the single-satellite direct positioning scenario can be achieved, providing an effective method for single-satellite passive direct positioning equipped with array antennas.

[0146] A specific implementation example is provided below.

[0147] Assuming that the satellite receives the radiation source signal from the earth's surface and estimates its position in a total of 6 time slots at 0, 2, 4, 6, 8 and 10 seconds, the satellite's position at time 0 is: latitude 30.591°N, longitude 103.048°E, altitude 505.5km; and assuming that the number of ground radiation sources is Q = 4, the positions (latitude, longitude, altitude) are (30.6667°N, 104.067°E, 0km), (29.5628°N, 106.553°E, 0km), (36.0564°N, 103.792°E, 0km) and (30.3043°N, 106.401°E, 0km). The center frequency f of the ground radiation source signal is c The frequency is 1 GHz, the radiation source signal is a randomly generated binary phase shift keying (BPSK) signal, the bandwidth is 1 kHz, and the channel attenuation model is β ql =1+δ ql , where δ ql is a complex Gaussian random variable with mean 0 and variance 0.1.

[0148] Figure 3 The satellite position and the real position of the radiation source in each time slot are shown, wherein the black solid line is the motion trajectory of the satellite sub-satellite point, and the five-pointed star is the radiation source position. The result of this figure will be used as a reference for statistically estimating the radiation source position error of the present invention.

[0149] Assume that the rotation speed of the uniform linear array carried on the satellite is In each time slot, the satellite samples K = 2000 snapshots, and each D = 20 snapshots are divided into a segment, which is divided into N = 100 segments in total. Therefore, according to the above steps, the positioning effect diagram of the present invention can be obtained, as shown in FIG. Figure 4As shown in the figure, it can be seen that the method proposed in the present invention can realize the single-star direct positioning of multiple radiation sources with high positioning accuracy and resolution.

[0150] The present invention uses the root mean square error (RMSE) of the positioning result to evaluate the position estimation accuracy of the proposed method, which is defined as follows:

[0151]

[0152] Wherein, C represents the number of Monte Carlo simulations, which is set to 500 times in the embodiment of the present invention, and p q represents the true position of the qth radiation source, represents the estimated position of the qth radiation source obtained by the cth simulation.

[0153] Figure 5 The figure shows the relationship between the root mean square error of the positioning result obtained by an embodiment of the present invention and the signal-to-noise ratio. It can be seen from the figure that the method proposed by the present invention has better positioning accuracy than other comparison methods.

[0154] The following describes an apparatus embodiment of the present application, which can be used to execute a single-satellite direct positioning method based on a space-time signal model in the above-mentioned embodiment of the present application. For details not disclosed in the apparatus embodiment of the present application, please refer to the above-mentioned method embodiment of the present application.

[0155] Reference Figure 6 As shown, according to an embodiment of the present application, a single-satellite direct positioning device 600 based on a space-time signal model includes:

[0156] A first establishing unit 601 is used to establish a rotating array model;

[0157] The first conversion unit 602 is used to convert the Earth-centered Earth-fixed coordinates of the radiation source into the station-centered line-of-sight coordinates using a coordinate conversion formula;

[0158] The second establishing unit 603 is used to construct a receiving signal model based on the station center line of sight coordinates of the radiation source and the rotating array model;

[0159] The second conversion unit 604 is used to convert the received signal model into a space-time signal model for single-satellite direct positioning;

[0160] A design unit 605 is used to design a single-satellite direct positioning cost function based on the space-time signal model;

[0161] A calculation unit 606 is used to obtain the geocentric earth-fixed coordinates corresponding to the longitude and latitude area where the radiation source may exist, and calculate the cost function spectrum value based on the geocentric earth-fixed coordinates and the single-satellite direct positioning cost function;

[0162] A processing unit 607 is used to perform modulus and normalization processing on the cost function spectrum value;

[0163] The determination unit 608 is used to determine the target position to be located based on the processed cost function spectrum value.

[0164] like Figure 7 As shown, an embodiment of the present application also provides an electronic device 700, including a memory 710, a processor 720, and a computer program 711 stored in the memory 710 and executable on the processor. When the processor 720 executes the computer program 711, the steps of the above-mentioned single-satellite direct positioning method based on the space-time signal model are implemented.

[0165] Since the electronic device introduced in this embodiment is a device used to implement a single-star direct positioning device based on a space-time signal model in the embodiment of the present application, based on the method introduced in the embodiment of the present application, the technical personnel in this field can understand the specific implementation mode of the electronic device of this embodiment and its various variations. Therefore, how the electronic device implements the method in the embodiment of the present application is not introduced in detail here. As long as the equipment adopted by the technical personnel in this field to implement the method in the embodiment of the present application, it belongs to the scope of protection of this application.

[0166] During the specific implementation process, when the computer program 711 is executed by a processor, any implementation method in the embodiments corresponding to the first aspect can be implemented.

[0167] Figure 8 A schematic diagram of the structure of a computer system suitable for implementing an electronic device of an embodiment of the present application is shown.

[0168] It should be noted that Figure 8 The computer system 800 of the electronic device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0169] like Figure 8As shown, the computer system 800 includes a central processing unit (CPU) 801, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 802 or the program loaded from the storage part 808 to the random access memory (RAM) 803, such as executing the method described in the above embodiment. In the RAM 803, various programs and data required for system operation are also stored. The CPU 801, ROM 802 and RAM 803 are connected to each other through a bus 804. An input / output (I / O) interface 805 is also connected to the bus 804.

[0170] The following components are connected to the I / O interface 805: an input section 806 including a keyboard, a mouse, etc.; an output section 807 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker; a storage section 808 including a hard disk, etc.; and a communication section 809 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section 809 performs communication processing via a network such as the Internet. A drive 810 is also connected to the I / O interface 805 as needed. A removable medium 811, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 810 as needed so that a computer program read therefrom is installed into the storage section 808 as needed.

[0171] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication section 809, and / or installed from a removable medium 811. When the computer program is executed by a central processing unit (CPU) 801, various functions defined in the system of the present application are executed.

[0172] It should be noted that the computer-readable medium shown in the embodiment of the present application may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, - but not limited to - an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by an instruction execution system, device or device or used in combination with it. In the present application, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, wherein a computer-readable program code is carried. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, which may send, propagate, or transmit programs for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0173] The flowchart and block diagram in the accompanying drawings illustrate the possible architecture, functions and operations of the system, method and computer program product according to various embodiments of the present application. Wherein, each box in the flowchart or block diagram can represent a module, a program segment, or a part of the code, and the above-mentioned module, program segment, or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0174] The units involved in the embodiments described in this application may be implemented by software or hardware, and the units described may also be set in a processor. The names of these units do not, in some cases, constitute limitations on the units themselves.

[0175] As another aspect, the present application further provides a computer program product or a computer program, the computer program product or the computer program including computer instructions, the computer instructions being stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes a single-satellite direct positioning method based on a space-time signal model described in the above embodiment.

[0176] As another aspect, the present application also provides a computer-readable medium, which may be included in the electronic device described in the above embodiment; or may exist independently without being assembled into the electronic device. The above computer-readable medium carries one or more programs, and when the above one or more programs are executed by an electronic device, the electronic device implements a single-satellite direct positioning method based on a space-time signal model described in the above embodiment.

[0177] It should be noted that, although several modules or units of the equipment for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to the embodiments of the present application, the features and functions of two or more modules or units described above can be embodied in one module or unit. On the contrary, the features and functions of one module or unit described above can be further divided into being embodied by multiple modules or units.

[0178] Through the description of the above implementation methods, it is easy for those skilled in the art to understand that the example implementation methods described here can be implemented by software or by combining software with necessary hardware. Therefore, the technical solution according to the implementation methods of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes several instructions to enable a computing device (which can be a personal computer, a server, a touch terminal, or a network device, etc.) to execute the method according to the implementation methods of the present application.

[0179] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the embodiments disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary techniques in the art that are not disclosed in the present application. It should be understood that the present application is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A single-satellite direct positioning method based on a space-time signal model, characterized in that: include: Establish a rotating array model; The coordinate conversion formula is used to convert the Earth-centered Earth-fixed coordinates of the radiation source into the station-centered line-of-sight coordinates; Construct a receiving signal model based on the station center line of sight coordinates of the radiation source and the rotating array model; Convert the received signal model into a space-time signal model for single-satellite direct positioning; Designing a single-satellite direct positioning cost function based on the space-time signal model; Obtaining geocentric earth-fixed coordinates corresponding to the longitude and latitude regions where the radiation source may exist, calculating cost function spectrum values ​​based on the geocentric earth-fixed coordinates and the single-satellite direct positioning cost function, and performing modulus and normalization processing on the cost function spectrum values; The target position to be located is determined based on the processed cost function spectrum value.

2. The method according to claim 1, characterized in that The step of establishing a rotating array model comprises: Establishing the rotation array model based on formula (1); In formula (1), d0 represents the starting time array, d l represents the lth time slot array, x0 is the reference array element, the distance between two adjacent array elements is d, R rot is the rotation matrix, θ l is the counterclockwise rotation angle of the lth time slot array.

3. The method according to claim 2, characterized in that The coordinate conversion formula includes a conversion formula from geodetic coordinates to earth-centered earth-fixed coordinates and a conversion formula from earth-centered earth-fixed coordinates to station-centered line-of-sight coordinates.

4. The method according to claim 3, characterized in that The receiving signal model is constructed based on the station center line of sight coordinates of the radiation source and the rotating array model, including: Assuming that the satellite receives Q radiation source signals from the earth's surface in L time slots, the received signal model is established based on formula (2); In formula (2), r l (k) represents the kth received signal, β ql represents the channel attenuation, s ql (k) represents the baseband signal sent by the qth radiation source in the lth time slot, is the Doppler shift, where λ is the wavelength, u l =[x l ,y l ,z l ] T and v l They represent the position and velocity of the satellite in the Earth-centered Earth-fixed coordinate system at the lth time slot, T s =1 / f s is the sampling interval, n l (k) is zero-mean complex Gaussian white noise, represents the spatial array response, where p q =[x q,e ,y q,e ,z q,e ] T is the Earth-fixed position coordinate of the qth radiation source, f c is the center frequency, ε m (p q ) represents the phase difference of the qth radiation source signal at array element m relative to the reference array element, ε m (p q ) is expressed as follows: Among them, x m is the coordinate of the mth array element relative to the reference array element, θ ql =arctan(y q,g / x q,g ) is the incident azimuth, is the incident pitch angle, where x q,g ,y q,g and z q,g are the satellite station line of sight coordinates, θ l Represents the angle between the array and the positive direction of the satellite platform's x-axis; where l = 1, 2, ..., L, q = 1, 2, ..., Q.

5. The method according to claim 4, characterized in that The designing of a single-satellite direct positioning cost function based on the space-time signal model comprises: Calculating a covariance matrix of the space-time received signal; Performing forward and backward smoothing on the covariance matrix; Divide the processed covariance matrix into D×D block matrices of the same size, where D is the number of snapshots in a segment; Perform Toeplitz matrix adjustment on all block matrices separately; Perform unitary transformation on the adjusted block matrix to obtain a real-valued covariance matrix; Performing eigenvalue decomposition on the real-valued covariance matrix; The single-star direct positioning cost function is constructed based on the decomposition result.

6. The method according to claim 1, characterized in that The step of obtaining the geocentric earth-fixed coordinates corresponding to the latitude and longitude region where the radiation source may exist, and calculating the cost function spectrum value based on the geocentric earth-fixed coordinates and the single-satellite direct positioning cost function includes: A set of grid points is set for the latitude and longitude areas where the radiation source may exist in the geodetic coordinate system, and a set of corresponding geocentric earth-fixed coordinates in the geocentric earth-fixed coordinate system is obtained through the coordinate system conversion formula; Based on the corresponding earth-centered earth-fixed coordinates in the earth-centered earth-fixed coordinate system and the single-satellite direct positioning cost function, a cost function spectrum value is calculated.

7. The method according to claim 1, characterized in that The determining the target position to be located based on the processed cost function spectrum value includes: Setting a threshold of the cost function spectrum value, and removing the cost function spectrum values ​​below the threshold; The conventional maximum value method is used to calculate the maximum values ​​in the cost function spectrum value, and the geodetic coordinates of the corresponding grid points are output; The target position is determined based on the geodetic coordinates.

8. A single-satellite direct positioning device based on a space-time signal model, characterized in that: include: A first establishing unit is used to establish a rotating array model; A first conversion unit is used to convert the Earth-centered Earth-fixed coordinates of the radiation source into the station-centered line-of-sight coordinates using a coordinate conversion formula; The second establishing unit is used to construct a receiving signal model based on the station center line of sight coordinates of the radiation source and the rotating array model; A second conversion unit, used for converting the received signal model into a space-time signal model for single-satellite direct positioning; A design unit, used for designing a single-satellite direct positioning cost function based on the space-time signal model; A calculation unit, used for obtaining the geocentric earth-fixed coordinates corresponding to the longitude and latitude area where the radiation source may exist, and calculating the cost function spectrum value based on the geocentric earth-fixed coordinates and the single-satellite direct positioning cost function; A processing unit, used for performing modulo and normalization processing on the cost function spectrum value; The determination unit is used to determine the target position to be located based on the processed cost function spectrum value.

9. A computer-readable storage medium, characterized in that: The storage medium stores computer instructions, and when the computer instructions are executed on a computer, the computer is enabled to execute the method according to any one of claims 1 to 7.

10. An electronic device, characterized in that: including memory and processor; The memory is used to store computer instructions; The processor is used to call the computer instructions stored in the memory so that the electronic device executes the method as described in any one of claims 1-7.

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