Method and device for estimating arrival angle-polarization information of short-wave sky wave signal

Abstract

The invention relates to the technical field of short-wave radio, in particular to a short-wave sky wave signal arrival angle-polarization information estimation method and device, and the method comprises the steps: receiving a short-wave sky wave signal through employing a preset short-wave three-component polarization receiving antenna array; and based on a rank deficiency MUSIC algorithm and a multi-core parallel operation optimization strategy, executing corresponding array signal processing, information source number estimation and multi-stage spectrum peak search operation in a preset DSP processor to obtain arrival angle estimation information and polarization angle estimation information of the short-wave sky wave signal. According to the electromagnetic vector receiving antenna array and the DSP processing method, the arrival angle and the polarization information of the sky wave signal are estimated at the same time, so that a basis is provided for accurate direction finding of the sky wave signal, signal quality improvement and ionosphere radio wave propagation environment research.

Description

Technical Field

[0001] The present application relates to the field of shortwave radio technology, and in particular to a method and device for estimating arrival angle-polarization information of a shortwave skywave signal. Background Art

[0002] Shortwave radio systems have irreplaceable advantages over other frequency bands due to their low cost, long range, large service area, and strong anti-destruction capability. They are widely used in shortwave broadcasting, shortwave telecommunications, and high-frequency skywave over-the-horizon radar. Estimating the arrival angle of shortwave signals helps to locate transmitters and detection targets, and has great application value in shortwave radio management, electronic reconnaissance, and emergency communications. Once the arrival angle and polarization parameters of shortwave skywave signals are known, the angle mismatch and polarization mismatch at the receiving end can be corrected through spatial or polarization domain filtering, thereby suppressing ionospheric clutter and improving the quality of received signals. In addition, by using the signal arrival angle and polarization information, the characteristics of the ionosphere can also be studied in reverse.

[0003] However, when shortwave signals are transmitted in sky wave propagation mode through refraction of the ionosphere, the complex time-space-frequency characteristics of the ionosphere cause the signal's arrival angle and polarization information to change, affecting the signal's reception performance, which needs to be solved urgently. Summary of the invention

[0004] The present application provides a method and device for estimating the arrival angle-polarization information of a shortwave skywave signal, so as to solve the problem that in the prior art, during the transmission of the shortwave signal in a skywave propagation mode, the arrival angle and polarization information of the shortwave signal are easily changed, which greatly affects the reception performance of the shortwave signal.

[0005] The first aspect of the present application provides a method for estimating the arrival angle-polarization information of a shortwave skywave signal, comprising the following steps: using a preset shortwave three-component polarization receiving antenna array to receive the shortwave skywave signal; based on a rank-deficient MUSIC algorithm and a multi-core parallel computing optimization strategy, performing corresponding array signal processing, information source number estimation, and multi-level spectrum peak search operations in a preset DSP processor to obtain the arrival angle estimation information and polarization angle estimation information of the shortwave skywave signal.

[0006] Optionally, in one embodiment of the present application, before executing the corresponding array signal processing, source number estimation and multi-level spectrum peak search operations in the preset DSP processor, it also includes: determining a target multi-core processor corresponding to the DSP processor and a target FPGA development board corresponding to a preset FPGA chip; performing preset signal processing on the shortwave skywave signal through the FPGA chip, and transmitting the shortwave skywave signal after signal processing from the target FPGA development board to the target multi-core processor equipped with a SYS / BIOS operating system through the SRIO data interface.

[0007] Optionally, in one embodiment of the present application, the rank-deficient MUSIC algorithm includes: sampling the shortwave skywave signal using the shortwave three-component polarized receiving antenna array to obtain at least one snapshot sample point; generating an array output signal according to the at least one snapshot sample point, and calculating the maximum likelihood estimate of the autocovariance matrix of the array output signal; based on the maximum likelihood estimate, eigendecomposing the autocovariance matrix of the array output signal to obtain multiple eigenvalues; sorting the multiple eigenvalues ​​to generate a signal subspace and a noise subspace, and the matrix of the noise subspace The value is stored in a preset shared memory; a first-level spectrum peak search range, a first-level search step value, a second-level spectrum peak search range and a second-level search step value corresponding to the multi-level spectrum peak search operation are determined; based on the first-level spectrum peak search range, the first-level search step value, the second-level spectrum peak search range and the second-level search step value, and in combination with a preset spectral density algorithm, a multi-level spectrum peak search operation is performed to obtain the arrival angle-polarization estimation information, wherein the arrival angle estimation information and the polarization angle estimation information include an azimuth angle estimation value, a pitch angle estimation value, a polarization auxiliary angle estimation value and a polarization phase angle estimation value.

[0008] Optionally, in one embodiment of the present application, the performing of corresponding array signal processing, information source number estimation, and multi-level spectrum peak search operations in a preset DSP processor to obtain arrival angle estimation information and polarization angle estimation information of the shortwave skywave signal includes: based on the first-level search step value, performing a first-level spectrum peak search operation within the first-level spectrum peak search range to obtain position information and amplitude information of all spectrum peaks within the first-level spectrum peak search range; sorting all the spectrum peaks in descending order according to the amplitude information to obtain a first-level sorting result, and obtaining position information corresponding to the first K spectrum peaks of the first-level sorting result, so as to obtain the first-level spectrum peak search result of the shortwave skywave signal through the position information corresponding to the first K spectrum peaks; and judging whether the first-level spectrum peak search result meets a preset accuracy requirement, wherein if the first-level spectrum peak search result meets the preset accuracy requirement, The first-level spectrum peak search operation is terminated, and the arrival angle estimation information is generated, and a polarization angle estimation operation is performed according to the arrival angle estimation information to obtain polarization angle estimation information, wherein K is a positive integer; if the first-level spectrum peak search result does not meet the preset accuracy requirement, a second-level spectrum peak search operation is performed within the second-level spectrum peak search range according to the second-level search step value to obtain all spectrum peaks in the second-level spectrum peak search area, and all spectrum peaks in the second-level spectrum peak search area are sorted in descending order to obtain a second-level sorting result, and the arrival angle information corresponding to the first K spectrum peaks of the second-level sorting result is obtained; it is determined whether the arrival angle information meets the preset accuracy requirement, wherein if the preset accuracy requirement is not met, the second-level spectrum peak search operation is repeated, otherwise the second-level spectrum peak search operation is terminated, and the arrival angle estimation information and the polarization angle estimation information are obtained.

[0009] Optionally, in one embodiment of the present application, the multi-core parallel computing optimization strategy includes: determining a plurality of overlapping interval critical values ​​corresponding to the first-level spectrum peak search range, and evenly dividing the first-level spectrum peak search range into a plurality of search intervals according to the plurality of overlapping interval critical values; performing a first-level spectrum peak search operation through the plurality of search intervals and the target multi-core processor to obtain the maximum spectrum peak of the master core and each slave core in the target multi-core processor and the azimuth and elevation angle corresponding to the maximum spectrum peak; sending the maximum spectrum peak of each slave core and the azimuth and elevation angle corresponding to the maximum spectrum peak to the master core, so that the master core can obtain the maximum spectrum peak of each slave core according to the azimuth and elevation angle of each slave core. The invention relates to a method for obtaining a true spectrum peak from an azimuth angle and an elevation angle corresponding to the maximum spectrum peak of a core; determining an arrival angle corresponding to the true spectrum peak according to the azimuth angle and the elevation angle corresponding to the true spectrum peak, and judging whether the arrival angle meets a preset range requirement; if the arrival angle meets the preset range requirement, performing a second-level spectrum peak search operation according to the second-level search step value, and calling the matrix value of the noise subspace in the shared memory through the target multi-core processor, so that the target multi-core processor performs parallel calculation according to the matrix value of the noise subspace and the preset spectrum density algorithm to obtain the arrival angle estimation information and the polarization angle estimation information.

[0010] Optionally, in one embodiment of the present application, the mathematical expression of the preset spectral density algorithm is:

[0011]

[0012] Among them, θ k represents the azimuth of the kth shortwave skywave signal; represents the elevation angle of the k-th shortwave skywave signal; γ k represents the polarization auxiliary angle of the k-th shortwave skywave signal; η k represents the polarization phase angle of the k-th shortwave skywave signal; represents the steering vector of the array; h(γ, η) represents the polarization steering vector; U N represents the noise subspace; represents the conjugate transpose of the noise subspace; H represents the conjugate transpose.

[0013] The second aspect of the present application provides an arrival angle-polarization information estimation device for a shortwave skywave signal, including: a receiving module, used to receive a shortwave skywave signal using a preset shortwave three-component polarization receiving antenna array; an estimation module, used to perform corresponding array signal processing, information source number estimation, and multi-level spectrum peak search operations in a preset DSP processor based on a rank-deficient MUSIC algorithm and a multi-core parallel computing optimization strategy, to obtain arrival angle estimation information and polarization angle estimation information of the shortwave skywave signal.

[0014] Optionally, in one embodiment of the present application, it also includes: a setting module, used to determine the target multi-core processor corresponding to the DSP processor and the target FPGA development board corresponding to the preset FPGA chip before executing the corresponding array signal processing, source number estimation and multi-level spectrum peak search operations in the preset DSP processor; a processing module, used to perform preset signal processing on the shortwave skywave signal through the FPGA chip, and transmit the shortwave skywave signal after signal processing from the target FPGA development board to the target multi-core processor equipped with the SYS / BIOS operating system through the SRIO data interface.

[0015] Optionally, in one embodiment of the present application, the estimation module includes: a sampling unit, used to sample the shortwave skywave signal using the shortwave three-component polarized receiving antenna array to obtain at least one snapshot sample point; a calculation unit, used to generate an array output signal according to the at least one snapshot sample point, and calculate the maximum likelihood estimate of the autocovariance matrix of the array output signal; a decomposition unit, used to perform eigendecomposition on the autocovariance matrix of the array output signal based on the maximum likelihood estimate to obtain multiple eigenvalues; a storage unit, used to sort the multiple eigenvalues ​​to generate a signal subspace and a noise subspace, and store the noise subspace The matrix values ​​are stored in a preset shared memory; a first determining unit is used to determine a first-level spectrum peak search range, a first-level search step value, a second-level spectrum peak search range and a second-level search step value corresponding to the multi-level spectrum peak search operation; a searching unit is used to perform a multi-level spectrum peak search operation based on the first-level spectrum peak search range, the first-level search step value, the second-level spectrum peak search range and the second-level search step value, and in combination with a preset spectrum density algorithm to obtain the arrival angle-polarization estimation information, wherein the arrival angle estimation information and the polarization angle estimation information include an azimuth angle estimation value, an elevation angle estimation value, a polarization auxiliary angle estimation value and a polarization phase angle estimation value.

[0016] Optionally, in one embodiment of the present application, the estimation module further includes: an acquisition unit, configured to perform a first-level spectrum peak search operation within the first-level spectrum peak search range based on the first-level search step value to obtain position information and amplitude information of all spectrum peaks within the first-level spectrum peak search range; a first sorting unit, configured to sort all the spectrum peaks in descending order according to the amplitude information to obtain a first-level sorting result, and obtain position information corresponding to the first K spectrum peaks of the first-level sorting result to obtain a first-level spectrum peak search result of the shortwave skywave signal through the position information corresponding to the first K spectrum peaks; a first judgment unit, configured to judge whether the first-level spectrum peak search result meets a preset accuracy requirement, wherein if the first-level spectrum peak search result meets the preset accuracy requirement, the first-level spectrum peak search operation is terminated, and the arrival angle estimation information is generated, and A polarization angle estimation operation is performed according to the arrival angle estimation information to obtain polarization angle estimation information, wherein K is a positive integer; a second sorting unit is used to perform a second-level spectrum peak search operation within the second-level spectrum peak search range according to the second-level search step value if the first-level spectrum peak search result does not meet the preset accuracy requirement, obtain all spectrum peaks in the second-level spectrum peak search area, and sort all spectrum peaks in the second-level spectrum peak search area in descending order to obtain a second-level sorting result, and obtain the arrival angle information corresponding to the first K spectrum peaks of the second-level sorting result; a second judgment unit is used to judge whether the arrival angle information meets the preset accuracy requirement, wherein if the preset accuracy requirement is not met, the second-level spectrum peak search operation is repeated, otherwise the second-level spectrum peak search operation is terminated, and the arrival angle estimation information and the polarization angle estimation information are obtained.

[0017] Optionally, in one embodiment of the present application, the estimation module further includes: a second determination unit, configured to determine a plurality of overlapping interval critical values ​​corresponding to the first-level spectrum peak search range, and evenly divide the first-level spectrum peak search range into a plurality of search intervals according to the plurality of overlapping interval critical values; an execution unit, configured to perform a first-level spectrum peak search operation through a plurality of search intervals and a target multi-core processor to obtain the maximum spectrum peak of a master core and each slave core in the target multi-core processor and the azimuth and elevation angle corresponding to the maximum spectrum peak; a sending unit, configured to send the maximum spectrum peak of each slave core and the azimuth and elevation angle corresponding to the maximum spectrum peak to the master core, so that the master core can determine the maximum spectrum peak of each slave core according to the azimuth and elevation angle corresponding to the maximum spectrum peak. A real spectrum peak is obtained from the azimuth and elevation angle corresponding to the maximum spectrum peak of each slave core; a third determining unit is used to determine the arrival angle corresponding to the real spectrum peak according to the azimuth and elevation angle corresponding to the real spectrum peak, and judge whether the arrival angle meets the preset range requirement; a calling unit is used to perform a second-level spectrum peak search operation according to the second-level search step value if the arrival angle meets the preset range requirement, and call the matrix value of the noise subspace in the shared memory through the target multi-core processor, so that the target multi-core processor performs parallel calculations according to the matrix value of the noise subspace and the preset spectral density algorithm to obtain the arrival angle estimation information and the polarization angle estimation information.

[0018] Optionally, in one embodiment of the present application, the mathematical expression of the preset spectral density algorithm is:

[0019]

[0020] Among them, θ k represents the azimuth of the kth shortwave skywave signal; represents the elevation angle of the k-th shortwave skywave signal; γ k represents the polarization auxiliary angle of the k-th shortwave skywave signal; η k represents the polarization phase angle of the k-th shortwave skywave signal; represents the steering vector of the array; h(γ, η) represents the polarization steering vector; U N represents the noise subspace; represents the conjugate transpose of the noise subspace; H represents the conjugate transpose.

[0021] A third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for estimating the arrival angle-polarization information of the shortwave skywave signal as described in the above embodiment.

[0022] The fourth aspect of the present application provides a computer-readable storage medium, which stores a computer program. When the program is executed by a processor, it implements the above method for estimating the arrival angle-polarization information of the shortwave skywave signal.

[0023] The fifth aspect of the present application provides a computer program product, including a computer program, which is executed to implement the above-mentioned method for estimating the arrival angle-polarization information of the shortwave skywave signal.

[0024] Therefore, the embodiments of the present application have the following beneficial effects:

[0025] The embodiments of the present application can utilize a preset shortwave three-component polarized receiving antenna array to receive shortwave skywave signals; based on the rank-deficient MUSIC algorithm and multi-core parallel computing optimization strategy, the corresponding array signal processing, source number estimation, and multi-level spectrum peak search operations are performed in a preset DSP processor to obtain the arrival angle estimation information and polarization angle estimation information of the shortwave skywave signal. The present application estimates the arrival angle and polarization information of the skywave signal at the same time based on the electromagnetic vector receiving antenna array and DSP processing method, thereby providing a basis for accurate direction finding of skywave signals, improving signal quality, and studying the ionospheric radio wave propagation environment. Thus, the problem of the prior art that the arrival angle and polarization information of the shortwave signal are easily changed during the transmission of the shortwave signal in the skywave propagation mode, which greatly affects the receiving performance of the shortwave signal, is solved.

[0026] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0028] Figure 1 A flowchart of a method for estimating the arrival angle-polarization information of a shortwave skywave signal provided according to an embodiment of the present application;

[0029] Figure 2 A schematic diagram of the composition framework of a shortwave skywave multi-channel electromagnetic vector receiving system provided for one embodiment of the present application;

[0030] Figure 3 A schematic diagram of a signal arrival angle-polarization secondary spectrum peak search process provided for one embodiment of the present application;

[0031] Figure 4 An 8-core two-dimensional arrival angle search range diagram provided for an embodiment of the present application;

[0032] Figure 5 A schematic diagram of a data flow mode topology structure provided for an embodiment of the present application;

[0033] Figure 6 A schematic diagram of an interrupt control flow of SRIO (Serial RapidIO, high-speed serial IO port) provided for one embodiment of the present application;

[0034] Figure 7 A schematic diagram of the overall process of implementing a DSP (Digital Signal Processing) algorithm provided for one embodiment of the present application;

[0035] Figure 8 A schematic diagram of a horizontally polarized dipole uniform circular array provided for one embodiment of the present application;

[0036] Fig. 9 This is an exemplary diagram of an arrival angle-polarization information estimation device for a shortwave skywave signal according to an embodiment of the present application;

[0037] Fig.10 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application.

[0038] Among them, 10 is an arrival angle-polarization information estimation device for shortwave skywave signals; 100 is a receiving module, 200 is an estimation module; 1001 is a memory, 1002 is a processor, and 1003 is a communication interface. DETAILED DESCRIPTION

[0039] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0040] The following describes the arrival angle-polarization information estimation method and device of the shortwave skywave signal of the embodiment of the present application with reference to the accompanying drawings. In view of the problems mentioned in the above background technology, the present application provides an arrival angle-polarization information estimation method of the shortwave skywave signal, in which a preset shortwave three-component polarization receiving antenna array is used to receive the shortwave skywave signal; based on the rank-deficient MUSIC (Multiple Signal Classification) algorithm and the multi-core parallel computing optimization strategy, the corresponding array signal processing, source number estimation and multi-level spectrum peak search operation are performed in the preset DSP processor to obtain the arrival angle estimation information and polarization angle estimation information of the shortwave skywave signal. According to the electromagnetic vector receiving antenna array and the DSP processing method, the present application simultaneously estimates the arrival angle and polarization information of the skywave signal, thereby providing a basis for the accurate direction finding of the skywave signal, the improvement of the signal quality and the research on the ionospheric radio wave propagation environment. As a result, the prior art solves the problem that the arrival angle and polarization information of the shortwave signal are easily changed during the transmission of the shortwave signal in the skywave propagation mode, which greatly affects the receiving performance of the shortwave signal.

[0041] Specifically, Figure 1 A flowchart of a method for estimating the arrival angle-polarization information of a shortwave skywave signal provided in an embodiment of the present application.

[0042] like Figure 1 As shown, the method for estimating the arrival angle-polarization information of the shortwave skywave signal comprises the following steps:

[0043] In step S101, a shortwave skywave signal is received using a preset shortwave three-component polarization receiving antenna array.

[0044] In step S102, based on the rank-deficient MUSIC algorithm and the multi-core parallel computing optimization strategy, the corresponding array signal processing, source number estimation and multi-level spectrum peak search operations are performed in the preset DSP processor to obtain the arrival angle estimation information and polarization angle estimation information of the shortwave skywave signal.

[0045] Optionally, in one embodiment of the present application, before executing corresponding array signal processing, source number estimation and multi-level spectrum peak search operations in a preset DSP processor, it also includes: determining a target multi-core processor corresponding to the DSP processor and a target FPGA development board corresponding to a preset FPGA (Field Programmable Gata Array) chip; performing preset signal processing on the shortwave skywave signal through the FPGA chip, and transmitting the shortwave skywave signal after signal processing from the target FPGA development board to the target multi-core processor equipped with a SYS / BIOS operating system through an SRIO data interface.

[0046] The embodiments of the present application can first select a suitable DSP processor and FPGA according to the composition framework, characteristics and implementation goals of the shortwave skywave multi-channel electromagnetic vector receiving system; then receive the shortwave skywave signal through the shortwave three-component polarization receiving antenna array, and solve the shortwave skywave signal in the DSP processor to obtain the arrival angle-polarization estimation information.

[0047] It should be noted that the shortwave skywave multi-channel electromagnetic vector receiving system consists of an electromagnetic vector receiving antenna array, a multi-channel radio frequency (RF) receiver, a multi-channel analog-to-digital conversion module (A / D) and a DSP information processing module (i.e., DSP processor).

[0048] Among them, the electromagnetic vector receiving antenna array can be a uniform circular array based on dipole antenna units or an L-shaped receiving antenna array based on orthogonal three-component receiving units or a two-dimensional coprime array, etc.; the DSP signal processing module adopts a high-performance multi-core processor TMS320XXX development board (i.e., the target multi-core processor) and uses the FPGA plus DSP working mode, and the FPGA in the embodiment of the present application can adopt the Xilinx Kintex-7 series development board XC7KYYY (i.e., the target FPGA development board), and because the FPGA is suitable for processing high-speed data and repetitive tasks, it can be used to perform RF front-end filtering, baseband frequency conversion, multi-channel acquisition and other operations, and send data to the DSP processor for processing through the high-speed SRIO data interface; and the DSP processor can be used for array signal processing due to its fast computing speed and suitability for processing complex processing tasks of low-rate data, so as to realize the estimation of signal arrival angle and polarization information.

[0049] As a feasible method, the core board of the embodiment of the present application includes DSP and FPGA chips, and can transmit data and interact with FPGA through SRIO channel, and the JTAG debugging port of FPGA and DSP can debug the algorithm on the development board through the emulator; the TMS320XXX development board in the embodiment of the present application can use the SYS / BIOS operating system to receive data from FPGA, and adopt the rank-deficient MUSIC algorithm as the arrival angle and polarization information estimation algorithm. The DSP hardware implementation of the arrival angle and polarization information estimation algorithm mainly includes multi-level spectrum peak search and multi-core parallel computing optimization strategy, so as to realize the hardware fast implementation of the arrival angle and polarization information estimation algorithm.

[0050] Optionally, in one embodiment of the present application, the rank-deficient MUSIC algorithm includes: sampling a shortwave skywave signal using a shortwave three-component polarized receiving antenna array to obtain at least one snapshot sample point; generating an array output signal according to the at least one snapshot sample point, and calculating a maximum likelihood estimate of an autocovariance matrix of the array output signal; based on the maximum likelihood estimate, eigendecomposing the autocovariance matrix of the array output signal to obtain a plurality of eigenvalues; sorting the plurality of eigenvalues ​​to generate a signal subspace and a noise subspace, and storing the matrix values ​​of the noise subspace in the signal subspace. The multi-level spectrum peak search operation is stored in a preset shared memory; a first-level spectrum peak search range, a first-level search step value, a second-level spectrum peak search range, and a second-level search step value corresponding to the multi-level spectrum peak search operation are determined; based on the first-level spectrum peak search range, the first-level search step value, the second-level spectrum peak search range, and the second-level search step value, and in combination with a preset spectrum density algorithm, a multi-level spectrum peak search operation is performed to obtain arrival angle-polarization estimation information, wherein the arrival angle estimation information and the polarization angle estimation information include an azimuth angle estimation value, a pitch angle estimation value, a polarization auxiliary angle estimation value, and a polarization phase angle estimation value.

[0051] It should be noted that the key steps of the multiple signal classification algorithm (Multiple Signal Classification, MUSIC) of the vector array in the embodiment of the present application are as follows:

[0052] 1. Using a shortwave three-component polarized receiving antenna array to sample the received signal (i.e., shortwave skywave signal) to obtain at least one snapshot sample point, and then obtaining the array output signal based on the snapshot sample point, and then solving the maximum likelihood estimation of its autocovariance matrix;

[0053] 2. Perform eigendecomposition on the covariance matrix of the array output signal to obtain multiple eigenvalues, and arrange the multiple eigenvalues ​​to obtain the signal subspace and the noise subspace;

[0054] 3. Set the appropriate search range (i.e., the first-level spectrum peak search range and the second-level spectrum peak search range corresponding to the multi-level spectrum peak search operation) and search step (i.e., the first-level search step value and the second-level search step value corresponding to the multi-level spectrum peak search operation), and perform the multi-level spectrum peak search operation to obtain the azimuth angle θ and the elevation angle of the shortwave skywave signal.

[0055] 4. According to the azimuth angle θ and elevation angle of the shortwave skywave signal And the amplitude of the signal, the polarization auxiliary angle γ and the polarization phase angle η of the shortwave skywave signal are obtained.

[0056] Therefore, the embodiments of the present application use a rank-deficient multiple signal classification algorithm including operations such as matrix multiplication, eigendecomposition, sorting, matrix eigenvalue decomposition (including QR decomposition, LU decomposition, etc.) to achieve spectral peak search of skywave signal arrival angle and polarization information, thereby completing the estimation of signal arrival angle, polarization auxiliary angle and polarization phase angle in DSP.

[0057] Optionally, in one embodiment of the present application, the mathematical expression of the preset spectral density algorithm is:

[0058]

[0059] Among them, θ k represents the azimuth of the kth shortwave skywave signal; represents the elevation angle of the kth shortwave skywave signal; γ k represents the polarization auxiliary angle of the kth shortwave skywave signal; η k represents the polarization phase angle of the kth shortwave skywave signal; represents the steering vector of the array; h(γ, η) represents the polarization steering vector; U N represents the noise subspace; represents the conjugate transpose of the noise subspace; H represents the conjugate transpose.

[0060] In the specific implementation process, the kth shortwave skywave signal reaches the angle based on the multiple signal classification algorithm of the vector array in the embodiment of the present application. and polarization auxiliary angle and polarization phase angle (γ k ,η k )The spectral density algorithm is:

[0061]

[0062] From the above formula, we can get: Where, represents the autocorrelation function

[0063] U N

[0064] R XX =E[XX H ], the noise subspace obtained by eigenvalue decomposition, XX is the signal received by the vector receiving antenna array, and

[0065]

[0066] Let n be the antenna number, is the position of the antenna, α and β are the angles between the projection of the antenna and the positive directions of the x-axis and z-axis respectively, then the following formula can be obtained:

[0067]

[0068] and

[0069]

[0070] e m =[sinβ m cosα m , sinβ m sinα m , cosβ m ,0,0,0]

[0071]

[0072] It should be noted that h(γ,η) is the following formula: There must be a non-zero solution:

[0073]

[0074] When the signal strength is obtained After that, the relationship between the polarization auxiliary angle, polarization phase angle (γ, η) and signal strength is:

[0075]

[0076] When performing the MUSIC algorithm, the number of signal sources can be estimated by using the AIC criterion, the MDL criterion, or the HQ criterion based on information theory.

[0077] Optionally, in one embodiment of the present application, corresponding array signal processing, information source number estimation, and multi-level spectrum peak search operations are performed in a preset DSP processor to obtain arrival angle estimation information and polarization angle estimation information of the shortwave skywave signal, including: based on the first-level search step value, performing a first-level spectrum peak search operation within the first-level spectrum peak search range to obtain position information and amplitude information of all spectrum peaks within the first-level spectrum peak search range; sorting all spectrum peaks in descending order according to the amplitude information to obtain a first-level sorting result, and obtaining position information corresponding to the first K spectrum peaks of the first-level sorting result, so as to obtain the first-level spectrum peak search result of the shortwave skywave signal through the position information corresponding to the first K spectrum peaks; judging whether the first-level spectrum peak search result meets the preset accuracy requirement, wherein if the first-level spectrum peak search result meets the preset accuracy requirement , then the first-level spectrum peak search operation is terminated, and arrival angle estimation information is generated, and a polarization angle estimation operation is performed according to the arrival angle estimation information to obtain polarization angle estimation information, wherein K is a positive integer; if the first-level spectrum peak search result does not meet the preset accuracy requirement, a second-level spectrum peak search operation is performed within the second-level spectrum peak search range according to the second-level search step value to obtain all spectrum peaks in the second-level spectrum peak search area, and all spectrum peaks in the second-level spectrum peak search area are sorted in descending order to obtain a second-level sorting result, and the arrival angle information corresponding to the first K spectrum peaks of the second-level sorting result is obtained; it is determined whether the arrival angle information meets the preset accuracy requirement, wherein if the preset accuracy requirement is not met, the second-level spectrum peak search operation is repeated, otherwise the second-level spectrum peak search operation is terminated, and the arrival angle estimation information and polarization angle estimation information are obtained.

[0078] In the embodiment of the present application, the specific steps of the multi-level spectrum peak search operation are as follows:

[0079] Step 1: Set the pitch angle θ and azimuth angle A step value (i.e., a first-level search step value) for a coarse precision search (i.e., a first-level spectrum peak search operation) is set to search within a search range of a two-dimensional arrival angle (i.e., a first-level spectrum peak search range), and the positions and amplitudes of all spectrum peaks that appear are recorded;

[0080] Step 2: Sort all peaks by amplitude from high to low, and take the positions corresponding to the first K (K is the number of information sources obtained by the information source number estimation) maximum values, and obtain the corresponding azimuth and elevation angles as the first-level spectrum peak search results; if the first-level spectrum peak search results meet the accuracy requirements, then end the first-level spectrum peak search operation, and obtain the estimated result of the arrival angle, and estimate the polarization angle based on the result; if the first-level spectrum peak search results do not meet the accuracy requirements, then perform the second-level spectrum peak search operation in step 3;

[0081] Step 3: within a certain range near the peak value obtained in step 2 (i.e., the second-level spectrum peak search range), select a smaller step value for fine search (i.e., the second-level search step value), continue to record and sort all the peaks that appear, select the largest K peaks and obtain the arrival angle information corresponding to the peaks, and judge the accuracy of the arrival angle information. If the accuracy of the arrival angle information meets the preset accuracy requirement, stop the second-level spectrum peak search operation of the arrival angle, and perform polarization information estimation to obtain the arrival angle estimation information and polarization angle estimation information. Otherwise, repeat step 3.

[0082] Therefore, the embodiment of the present application first performs a large-scale search to determine a search interval, and then performs a secondary peak search to perform a refined search operation within a small interval, thereby achieving rapid and accurate estimation of the arrival angle-polarization of the shortwave skywave propagation signal.

[0083] Optionally, in one embodiment of the present application, the multi-core parallel computing optimization strategy includes: determining a plurality of overlapping interval critical values ​​corresponding to the first-level spectrum peak search range, and evenly dividing the first-level spectrum peak search range into a plurality of search intervals according to the plurality of overlapping interval critical values; performing the first-level spectrum peak search operation through the plurality of search intervals and the target multi-core processor to obtain the maximum spectrum peak of the main core and each slave core in the multi-core processor and the azimuth and elevation angle corresponding to the maximum spectrum peak; sending the maximum spectrum peak of each slave core and the azimuth and elevation angle corresponding to the maximum spectrum peak to the main core so as to obtain the maximum spectrum peak of each slave core through the main core. The real spectrum peak is obtained according to the azimuth and elevation angles corresponding to the maximum spectrum peak of each slave core; the arrival angle corresponding to the real spectrum peak is determined according to the azimuth and elevation angles corresponding to the real spectrum peak, and it is judged whether the arrival angle meets the preset range requirement; if the arrival angle meets the preset range requirement, the second-level spectrum peak search operation is performed according to the second-level search step value, and the matrix value of the noise subspace in the shared memory is called through the target multi-core processor, so that the target multi-core processor performs parallel calculations according to the matrix value of the noise subspace and the preset spectral density algorithm to obtain arrival angle estimation information and polarization angle estimation information.

[0084] It should be noted that in the multi-core parallel computing optimization strategy of the embodiment of the present application, the topological structure between the cores can adopt a master-slave mode and a data flow mode, wherein in the master-slave mode, one of the multiple cores can be selected as the master core and the others as slave cores, and in the data flow mode each core depends on the processing result of the previous core.

[0085] In the actual implementation process, in order to avoid the change of the peak value when the critical value of multiple intervals is in the range, the embodiment of the present application can make the critical values ​​of adjacent intervals overlap to a certain extent when partitioning, that is, when multiple cores perform the first-level spectrum peak search operation, they search different angle ranges to improve the spectrum peak search speed, where the overall value range of the azimuth angle is θ∈[0°~360°], and the pitch angle is

[0086] Furthermore, the embodiments of the present application can evenly divide the azimuth search range into multiple intervals (i.e., multiple search intervals) to perform angle searches in multiple cores, and place the noise subspace matrix values ​​in a shared memory, which is called together by each core, and the operations are assigned to eight cores for parallel processing to reduce the time required for the operations, and improve the real-time performance of the operation while ensuring a certain degree of accuracy and correctness, thereby avoiding repeated operations.

[0087] As a feasible method, in the embodiment of the present application, the overall value range of the azimuth angle is θ∈[0°~360°], and according to the principle of the half-interval search method, a search is performed within the range of θ∈[0°~180°], and the pitch angle is After the multi-core processor completes the first-level spectrum peak search, the slave cores (e.g., seven slave cores) of the multi-core processor will each have their maximum value and corresponding θ, The value of is sent to the main core (such as core 0), which compares and selects the K largest peaks corresponding to θ. It is determined whether it is a real or false spectrum peak, and a second spectrum peak search with a smaller step value and an estimation of the polarization angle are performed within the range of plus or minus 1° of the arrival angle corresponding to the real spectrum peak.

[0088] It should be noted that after the angle range for azimuth search of each core in the multi-core processor is defined, each θ, Corresponding Each core stores the invariant property so that the next time the parameter estimation is performed, it does not need to be repeated. The operation is directly called and multiplied with the noise covariance to calculate the spectral density within the search range to speed up the operation.

[0089] It can be understood that the embodiments of the present application can establish a structure for efficient communication between multiple cores based on the characteristics of TMS320XXX and by utilizing modules such as multi-core communication, shared memory, multi-tasking threads and semaphores through a DSP processor, so as to quickly transmit data and notification information such as arrival angle estimation results, noise subspace addresses, and notification of each core to run or suspend waiting between the cores; it should be noted that when the DSP processor performs floating-point operations, the storage location of the variables in the operation can be customized through the cmd file constraint position, so as to dynamically and flexibly allocate and release the operation space of the array in the operation.

[0090] Therefore, the embodiments of the present application can enable multiple cores of TMS320XXX to perform spectrum peak search simultaneously, realize multi-level spectrum peak search and multi-core parallel operation in the DSP processor, and use the multi-level search method to further reduce the amount of calculation to improve the search speed.

[0091] The following takes a horizontally polarized dipole uniform circular array as an example, and describes in detail the execution process of the method for estimating the arrival angle-polarization information of the shortwave skywave signal of the present application through a specific embodiment and in combination with the accompanying drawings.

[0092] In the specific embodiments of the present application, Figure 2 As shown, the execution logic architecture of the shortwave skywave signal arrival angle-polarization estimation method of the present application mainly includes a vector array antenna receiving module, a multi-channel analog receiver module, a multi-channel signal acquisition module and a DSP signal processing module.

[0093] Among them, Figure 3 The horizontally polarized dipole uniform circular array shown performs energy conversion on the received shortwave skywave signals, converting the space shortwave skywave electromagnetic waves into high-frequency currents;

[0094] The multi-channel analog receiver module converts the signals from RF signals to IF signals after the vector receiving antenna is converted, and improves the signal reception quality through power amplification, filtering and other operations in the process;

[0095] The multi-channel signal acquisition module converts analog signals into digital signals by sampling and analog-to-digital conversion of multi-channel complex baseband signals for processing by the DSP processor. When implementing information processing hardware, the FPGA plus DSP working mode is adopted. The FPGA is responsible for RF front-end filtering, baseband frequency conversion, multi-channel acquisition and other operations. The DSP is mainly responsible for signal processing and is the focus and key part of the entire system.

[0096] In the specific embodiment of the present application, the hardware implementation of the signal arrival angle estimation mainly includes optimization strategies such as multi-level spectrum peak search, multi-core parallel operation, and half-interval search method of horizontal polarization dipole uniform circular array, such as Figure 4 shown.

[0097] Among them, the multi-level spectral peak search is to first conduct a large-scale search to determine a search interval, and then conduct a secondary peak search to perform a refined search in a small interval; multi-core parallel computing means that 8 cores search different angle ranges at the same time during the first-level peak search to improve the spectral peak search speed; the half-interval search method constructs a new spectral peak function and search steps to search within half of the interval.

[0098] It should be understood by those skilled in the art that the multi-level peak search gradually reduces the step value and the search range at each level until the accuracy requirement is met, thereby avoiding many redundant operations. Specifically, the steps of the multi-level peak search are as follows:

[0099] Step 1: Set the step value for the coarse-precision search of the azimuth and elevation angles, search within the search range of the two-dimensional arrival angle, and record the position and amplitude of all spectral peaks that appear;

[0100] Step 2: Sort all peaks by amplitude from high to low, take the positions corresponding to the first K (K is the number of information sources obtained by the information source number estimation) maximum values, and obtain the corresponding azimuth and elevation angles as the results of the first-level spectrum peak search; if the result meets the accuracy requirements, end the spectrum peak search, obtain the estimated result of the arrival angle and estimate the polarization angle based on the result; if the result does not meet the accuracy requirements, perform the second-level search operation;

[0101] Step 3: Select a smaller precision search step value within a certain range near the peak value obtained in step 2, continue to record and sort all the peaks that appear, select the largest K peaks and obtain the arrival angle information corresponding to the peaks, and judge the accuracy of the arrival angle information. If it meets the accuracy requirements, stop the spectral peak search operation of the arrival angle and perform polarization information estimation, otherwise repeat step 3.

[0102] It should be noted that when performing a multi-level spectrum peak search operation, the calculation of each angle spectrum density is independent, and the noise subspace autocovariance is used during the calculation. The calculation results are the same, so the azimuth search range can be evenly divided into eight intervals to perform angle search in eight cores, and the noise subspace matrix value can be put into shared memory and called by each core together to avoid repeated operations on it. The operations are distributed to the eight cores for parallel processing, which reduces the time required for operation. While ensuring a certain degree of accuracy and correctness, the real-time performance of the operation is effectively improved. At the same time, in order to avoid the change of the peak value at the critical value of the eight interval range, the specific embodiment of the present application can make the critical values ​​of adjacent intervals overlap to a certain extent when partitioning.

[0103] In the specific embodiment of the present application, the overall value range of the azimuth angle is θ∈[0°~360°]. According to the principle of the half-interval search method, a search is performed within the range of θ∈[0°~180°], as shown in Table 1. The pitch angle is After the eight cores complete the primary spectrum peak search, the seven slave cores will calculate their respective maximum values ​​and corresponding θ, The value of is sent to kernel 0, which compares and selects the K largest peaks corresponding to θ. And judge the real spectrum peak and false spectrum peak, and then perform a second spectrum peak search with a smaller step value and estimate the polarization angle within the range of + / - 1° corresponding to the arrival angle of the real spectrum peak; after the angle range of the azimuth search for each core is defined, each θ, Corresponding is constant, and each core can store it so that it does not need to be repeated the next time the parameters are estimated. The operation can be directly called and multiplied with the noise covariance to calculate the spectral density within the search range, which speeds up the operation to a certain extent, but also occupies a certain amount of storage space.

[0104] Table 1

[0105]

[0106] In order to better implement multi-level spectrum peak search and multi-core parallel computing in hardware, this application can establish a structure with simple logic, easy implementation, and efficient communication between cores based on the characteristics of TMS320XXX, and quickly transmit the arrival angle estimation results, noise subspace addresses, and notify each core to run or wait for data and notification information between cores. Since TMS320XXX uses the SYS / BIOS operating system to implement the algorithm modularly, the SYS / BIOS operating system can be used to decompose complex tasks into multiple tasks and perform task scheduling and implementation between multiple processes, thereby improving the utilization efficiency of CPU and memory resources and reducing unnecessary occupation.

[0107] Therefore, the multi-core implementation of the signal arrival angle and polarization information estimation can be divided into two task modules, the master core task and the slave core task, and the priority scheduling function Task_yield() is used to realize the switching between two tasks of the same priority in different cores. The semaphore module is used in the task to prevent multiple modules from executing at the same time. When a function in a task is completed, a certain operation of the next module is performed, realizing the communication between the master core and the slave core; semaphores mainly include mutual exclusion semaphores and counting semaphores, and mutual exclusion semaphores only include two states, 0 and 1; because the communication between the cores is relatively simple when performing arrival angle estimation, its role is only to notify the operation or suspension of the tasks of each core, so the hardware implementation of the estimation algorithm system uses mutual exclusion semaphores; when the semaphore is 1, the core is notified to run; if the semaphore is 0, it is suspended and waited, and the semaphore can be activated through IPC (Inter-Processor Communication).

[0108] It is understandable that since IPC inter-core communication mainly has several implementation methods, including minimum use, increased data path, increased dynamic allocation, and powerful but easy-to-use message mechanism, including Notify notification mechanism and MessageQ module. In order to minimize the transmission of shared memory addresses and unlock semaphores between cores and to be simple and convenient, this application can use the inter-core communication mode.

[0109] like Figure 5 and Figure 6As shown in the figure, the topological structure between the cores of multi-core parallel computing can adopt the master-slave mode and the data flow mode. In the master-slave mode, one of the cores is selected as the master core and the others are slave cores. The master core is responsible for unified control, and each core has an independent task. There is no communication between the slave cores. The control content of the master core over the entire process mainly includes communication with the FPGA and receiving data, the transmission of shared memory addresses between the cores, sending notification information of the slave core running or waiting, waiting for the notification information of the completion of each core operation, and the data transmission of the slave core output. There is no message transmission between the slave cores, the slave cores have the same tasks and process the data in parallel, while in the data flow mode, each core depends on the processing result of the previous core.

[0110] It can be seen from this that the data flow structure cannot achieve the purpose of eight cores performing spectrum peak search at the same time. Therefore, the system structure in this application adopts a master-slave mode. After the inter-core communication is started, the master core is connected to the slave core, and events are registered for the inter-core connection respectively; the message transmission between the master core and the slave core is through the Notify_sendEvent() function. In this system, before the master core sends information to the slave core, the task that the master core needs to complete is to receive and process the data, and then put the result into the shared memory; after the master core completes the task, it sends an event to the slave core, and the master and slave cores send messages to each other and enter the feedback function through the event number in the Notify_sendEvent() function. In the feedback function, the slave core can only perform operations after the semaphore is transferred and activated through the shared memory address. When the seven slave cores have completed the operation, the semaphore of the master core is activated, and the next operation of the master core continues; before the semaphore of each core is activated, the Semaphore_pend() function is used to keep the core hanging and waiting.

[0111] In a specific embodiment of the present application, the steps of the DSP processor using the shared memory to transfer noise subspace data are as follows:

[0112] (1) The main core applies for a shared memory area and names the memory area, and allocates appropriate memory space according to the size of the noise subspace matrix to be stored;

[0113] (2) The master core sends the address of the shared memory to each slave core, and each core performs address conversion after receiving the address;

[0114] (3) The slave core reads the autocovariance data of the noise subspace according to the shared memory address and performs the first level of spectrum peak search operation.

[0115] like Figure 7 As shown in the figure, the main steps of SRIO communication on the DSP processor side are:

[0116] (1) Enable and initialize the SRIO subsystem, set the SRIO communication to normal mode, configure it to x4 link connection mode, and set the device ID on the DSP side;

[0117] (2) Use Hwi to register the doorbell interrupt and notify the DSP main core to read the data sent to the DSP by the FPGA. The DSP responds to the SRIO doorbell interrupt in the interrupt service function and reads the data.

[0118] (3) Complete multi-core parallel processing operations for arrival angle and polarization information estimation in DSP.

[0119] The DSP processor reads data in the interrupt service routine, such as Figure 8 As shown, the overall process of DSP implementation of the signal arrival angle-polarization estimation algorithm is as follows Figure 5 As shown by Figure 5 It can be seen that the module under task 0 is the task to be completed by the master core 0, and the module under task 1 is the task to be completed by the slave cores 1 to 7; the two tasks have the same priority, and the task_yield() function is used to switch between tasks. After all tasks are completed, BIOS_exit(0) is used to exit. The tasks, that is, the master and slave cores, use semaphores to communicate; the specific contents of tasks A, B, C, and D in the flowchart, tasks A, B, and D belong to the master core tasks, 1, 2, and 3 represent the order in which events in the master core are completed, and task C belongs to the slave core task. Specifically:

[0120] Task A: Main Core Task 1

[0121] Data is received from the FPGA through SRIO, the noise subspace is obtained after feature decomposition, and then written into the shared memory. The master core sends events to each slave core and passes the shared memory address, so that the slave core starts running from the suspended state.

[0122] Task B: Main Core Task 2

[0123] After sending events to each slave core, the master core conducts first-level direction finding and performs a coarse-precision search. According to the divided request range, the search range of the master core 0 is θ∈(0°~23°). After the first-level spectrum peak search is completed, the master core suspends and waits until all slave cores complete direction finding, and then receives the completion signal from the 7 slave cores and the shared memory address where the operation results obtained from the first-level spectrum peak rough search are stored; then the semaphore is activated and the master core performs task 3.

[0124] Mission C: From the nuclear mission

[0125] After receiving the events sent by the master core, the seven slave cores obtain the shared memory address and perform their own address conversion, and read the autocovariance matrix data of the noise subspace from the shared memory; according to the divided request range, they perform slave core-level direction finding and then write the results to the shared memory; after each core completes the task, it sends a notification event and the shared memory address of the search result to the master core.

[0126] Mission D: Main Core Mission 3

[0127] After receiving the events of the seven slave cores and completing the primary direction finding of the master core, the semaphore is activated and the master core task 3 is performed; the master core reads the data written by the slave core into the shared memory, arranges all the spectrum peaks obtained by the search in descending order, screens the primary direction finding results by the corresponding peaks, and records the corresponding arrival angle information; if the half-interval search method is used, it is necessary to judge the real spectrum peak and the false spectrum peak of the result, and according to the results of the azimuth and elevation angles, perform a precise search of 0.1° steps within the estimated arrival angle of plus or minus 1° to complete the secondary direction finding of the master core and obtain the arrival angle estimate that meets the angle accuracy requirements; according to the estimated result of the arrival angle, the master core estimates the polarization parameters, completes the remaining operations of the algorithm, and finally outputs the arrival angle and polarization angle results.

[0128] In the entire data processing structure, the fixed memory area used by the data includes the data read from the FPGA stored in DDR3, and the results of the primary direction finding by the master core stored in the memory of the master core. The shared memory area mainly includes two parts: the data of the noise subspace stored in the master core and the result data of the primary direction finding stored in the seven slave cores; since the shared memory is used by eight cores at the same time, it should be divided into the master core storage area and the slave core storage area when used to avoid data overwriting.

[0129] In addition, it is verified that the receiving antenna array is a horizontally polarized dipole uniform circular array with 12 elements, a circular array radius of 15m, and a shortwave signal frequency of f=17.565MHz.

[0130] Table 2 shows the estimation results of the arrival angle and polarization information in the DSP processor:

[0131] Table 2

[0132] Clock cycle Hardware time consuming Eigendecomposition 1764587 1.765ms Single core first level peak search 480841254 480.841ms 8-core parallel first-level peak search 58481248 58.484ms Half-interval search method 37957782 37.958ms

[0133] Table 3 shows the clock cycles required to complete each operation and converts the clock count into DSP execution time:

[0134] Table 3

[0135]

[0136] It can be seen from Tables 2 and 3 that the present application can realize rapid estimation of the arrival angle-polarization of shortwave skywave propagation signals by adopting a shortwave electromagnetic vector receiving antenna array and based on a DSP processor. Not only is the processing result accurate, but the speed is also fast. It can provide reliable theoretical and technical support for improving the quality of shortwave skywave signals, accurately finding and positioning shortwave antenna signals, and studying the ionospheric radio wave propagation environment.

[0137] According to the method for estimating the arrival angle-polarization information of the shortwave skywave signal proposed in the embodiment of the present application, a preset shortwave three-component polarization receiving antenna array is used to receive the shortwave skywave signal; based on the rank-deficient MUSIC algorithm and the multi-core parallel computing optimization strategy, the corresponding array signal processing, source number estimation and multi-level spectrum peak search operations are performed in the preset DSP processor to obtain the arrival angle estimation information and polarization angle estimation information of the shortwave skywave signal. The present application estimates the arrival angle and polarization information of the skywave signal at the same time based on the electromagnetic vector receiving antenna array and the DSP processing method, thereby providing a basis for the precise direction finding of the skywave signal, the improvement of the signal quality and the research on the ionospheric radio wave propagation environment.

[0138] Next, the arrival angle-polarization information estimation device of the shortwave skywave signal proposed in the embodiment of the present application is described with reference to the accompanying drawings.

[0139] Fig. 9 It is a block diagram of an arrival angle-polarization information estimation device for a shortwave skywave signal according to an embodiment of the present application.

[0140] like Fig. 9 As shown, the arrival angle-polarization information estimation device 10 of the shortwave skywave signal includes: a receiving module 100 and an estimating module 200.

[0141] The receiving module 100 is used to receive shortwave skywave signals using a preset shortwave three-component polarization receiving antenna array.

[0142] The estimation module 200 is used to perform corresponding array signal processing, source number estimation and multi-level spectrum peak search operations in a preset DSP processor based on the rank-deficient MUSIC algorithm and multi-core parallel computing optimization strategy to obtain arrival angle estimation information and polarization angle estimation information of the shortwave skywave signal.

[0143] Optionally, in one embodiment of the present application, the arrival angle-polarization information estimation device 10 of the shortwave skywave signal in the embodiment of the present application further includes: a setting module and a processing module.

[0144] Among them, the setting module is used to determine the target multi-core processor corresponding to the DSP processor and the target FPGA development board corresponding to the preset FPGA chip before executing the corresponding array signal processing, source number estimation and multi-level spectrum peak search operations in the preset DSP processor.

[0145] The processing module is used to perform preset signal processing on the shortwave skywave signal through the FPGA chip, and transmit the shortwave skywave signal after signal processing from the target FPGA development board to the target multi-core processor equipped with the SYS / BIOS operating system through the SRIO data interface.

[0146] Optionally, in one embodiment of the present application, the estimation module 200 includes: a sampling unit, a calculation unit, a decomposition unit, a storage unit, a first determination unit and a search unit.

[0147] The sampling unit is used to sample the shortwave skywave signal using a shortwave three-component polarized receiving antenna array to obtain at least one snapshot sample point.

[0148] A computing unit is used to generate an array output signal according to at least one snapshot sample point, and to compute a maximum likelihood estimate of an autocovariance matrix of the array output signal.

[0149] The decomposition unit is used to perform eigendecomposition on the autocovariance matrix of the array output signal based on maximum likelihood estimation to obtain multiple eigenvalues.

[0150] A storage unit, used for sorting the multiple eigenvalues ​​to generate a signal subspace and a noise subspace, and storing the matrix value of the noise subspace in a preset shared memory;

[0151] The first determining unit is used to determine a first-level spectrum peak search range, a first-level search step value, a second-level spectrum peak search range and a second-level search step value corresponding to the multi-level spectrum peak search operation.

[0152] The search unit is used to perform a multi-level spectrum peak search operation based on a first-level spectrum peak search range, a first-level search step value, a second-level spectrum peak search range and a second-level search step value in combination with a preset spectrum density algorithm to obtain arrival angle-polarization estimation information, wherein the arrival angle estimation information and the polarization angle estimation information include an azimuth angle estimation value, a pitch angle estimation value, a polarization auxiliary angle estimation value and a polarization phase angle estimation value.

[0153] Optionally, in one embodiment of the present application, the estimation module 200 further includes: an acquisition unit, a first sorting unit, a first judgment unit, a second sorting unit and a second judgment unit.

[0154] The acquisition unit is used to perform a first-level spectrum peak search operation within a first-level spectrum peak search range based on a first-level search step value to acquire position information and amplitude information of all spectrum peaks within the first-level spectrum peak search range.

[0155] The first sorting unit is used to sort all spectrum peaks in descending order according to the amplitude information to obtain a first-level sorting result, and obtain position information corresponding to the first K spectrum peaks of the first-level sorting result, so as to obtain the first-level spectrum peak search result of the shortwave skywave signal through the position information corresponding to the first K spectrum peaks.

[0156] The first judgment unit is used to judge whether the first-level spectrum peak search result meets the preset accuracy requirement, wherein if the first-level spectrum peak search result meets the preset accuracy requirement, the first-level spectrum peak search operation is terminated, and arrival angle estimation information is generated, and a polarization angle estimation operation is performed according to the arrival angle estimation information to obtain the polarization angle estimation information, wherein K is a positive integer.

[0157] The second sorting unit is used to perform a second-level spectral peak search operation within a second-level spectral peak search range according to a second-level search step value if the first-level spectral peak search result does not meet the preset accuracy requirement, obtain all spectral peaks in the second-level spectral peak search area, and sort all spectral peaks in the second-level spectral peak search area in descending order to obtain a second-level sorting result, and obtain the arrival angle information corresponding to the first K spectral peaks of the second-level sorting result.

[0158] The second judgment unit is used to judge whether the arrival angle information meets the preset accuracy requirement, wherein if it does not meet the preset accuracy requirement, the second-level spectrum peak search operation is repeatedly performed, otherwise the second-level spectrum peak search operation is terminated, and the arrival angle estimation information and polarization angle estimation information are obtained.

[0159] Optionally, in one embodiment of the present application, the estimation module 200 further includes: a second determination unit, an execution unit, a sending unit, a third determination unit and a calling unit.

[0160] The second determination unit is used to determine a plurality of overlapping interval critical values ​​corresponding to the first-level spectrum peak search range, and evenly divide the first-level spectrum peak search range into a plurality of search intervals according to the plurality of overlapping interval critical values.

[0161] The execution unit is used to perform the first level spectrum peak search operation through multiple search intervals and the target multi-core processor to obtain the maximum spectrum peak of the main core and each slave core in the multi-core processor and the azimuth and elevation angle corresponding to the maximum spectrum peak.

[0162] The sending unit is used to send the maximum spectrum peak of each slave core and the azimuth and elevation angle corresponding to the maximum spectrum peak to the main core, so that the main core can obtain the real spectrum peak according to the azimuth and elevation angle corresponding to the maximum spectrum peak of each slave core.

[0163] The third determination unit is used to determine the arrival angle corresponding to the real spectrum peak according to the azimuth angle and the elevation angle corresponding to the real spectrum peak, and judge whether the arrival angle meets the preset range requirement.

[0164] The calling unit is used to perform a second-level spectrum peak search operation according to a second-level search step value if the arrival angle meets the preset range requirement, and call the matrix value of the noise subspace in the shared memory through the target multi-core processor, so that the target multi-core processor performs parallel calculations according to the matrix value of the noise subspace and a preset spectral density algorithm to obtain arrival angle estimation information and polarization angle estimation information.

[0165] Optionally, in one embodiment of the present application, the mathematical expression of the preset spectral density algorithm is:

[0166]

[0167] Among them, θ k represents the azimuth of the kth shortwave skywave signal; represents the elevation angle of the kth shortwave skywave signal; γ k represents the polarization auxiliary angle of the kth shortwave skywave signal; η k represents the polarization phase angle of the kth shortwave skywave signal; represents the steering vector of the array; h(γ, η) represents the polarization steering vector; U N represents the noise subspace; represents the conjugate transpose of the noise subspace; H represents the conjugate transpose.

[0168] It should be noted that the above explanation of the embodiment of the method for estimating the arrival angle-polarization information of a shortwave skywave signal is also applicable to the apparatus for estimating the arrival angle-polarization information of a shortwave skywave signal of this embodiment, which will not be described in detail here.

[0169] According to the shortwave skywave signal arrival angle-polarization information estimation device proposed in the embodiment of the present application, it includes a receiving module 100, which is used to receive the shortwave skywave signal using a preset shortwave three-component polarization receiving antenna array; an estimation module 200, which is used to perform corresponding array signal processing, source number estimation and multi-level spectrum peak search operations in a preset DSP processor based on a rank-deficient MUSIC algorithm and a multi-core parallel computing optimization strategy, to obtain the arrival angle estimation information and polarization angle estimation information of the shortwave skywave signal. The present application estimates the arrival angle and polarization information of the skywave signal at the same time based on the electromagnetic vector receiving antenna array and the DSP processing method, thereby providing a basis for accurate direction finding of the skywave signal, improving signal quality and studying the ionospheric radio wave propagation environment.

[0170] Fig.10 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include:

[0171] A memory 1001 , a processor 1002 , and a computer program stored in the memory 1001 and executable on the processor 1002 .

[0172] When the processor 1002 executes the program, the arrival angle-polarization information estimation method of the shortwave skywave signal provided in the above embodiment is implemented.

[0173] Furthermore, the electronic device further comprises:

[0174] The communication interface 1003 is used for communication between the memory 1001 and the processor 1002 .

[0175] The memory 1001 is used to store computer programs that can be executed on the processor 1002 .

[0176] The memory 1001 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0177] If the memory 1001, the processor 1002 and the communication interface 1003 are implemented independently, the communication interface 1003, the memory 1001 and the processor 1002 can be connected to each other through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig.10 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0178] Optionally, in a specific implementation, if the memory 1001, the processor 1002 and the communication interface 1003 are integrated on a chip, the memory 1001, the processor 1002 and the communication interface 1003 can communicate with each other through an internal interface.

[0179] The processor 1002 may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0180] An embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned method for estimating the arrival angle-polarization information of a shortwave skywave signal.

[0181] The embodiment of the present application further provides a computer program product, including a computer program, which, when executed, is used to implement the above-mentioned method for estimating the arrival angle-polarization information of the shortwave skywave signal.

[0182] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0183] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0184] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0185] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or N wirings (electronic devices), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways as necessary and then storing it in a computer memory.

[0186] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0187] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0188] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0189] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for estimating the arrival angle-polarization information of a shortwave skywave signal, characterized in that: The following steps are involved: Utilize a preset shortwave three-component polarized receiving antenna array to receive shortwave skywave signals; Based on the rank-deficient MUSIC algorithm and multi-core parallel computing optimization strategy, corresponding array signal processing, information source number estimation and multi-level spectrum peak search operations are performed in a preset DSP processor to obtain arrival angle estimation information and polarization angle estimation information of the shortwave skywave signal.

2. The method for estimating the arrival angle-polarization information of a shortwave skywave signal according to claim 1, characterized in that: Before executing the corresponding array signal processing, information source number estimation and multi-level spectrum peak search operations in the preset DSP processor, the method further includes: Determine a target multi-core processor corresponding to the DSP processor and a target FPGA development board corresponding to a preset FPGA chip; The FPGA chip performs preset signal processing on the shortwave skywave signal, and transmits the processed shortwave skywave signal from the target FPGA development board to a target multi-core processor equipped with a SYS / BIOS operating system through an SRIO data interface.

3. The method for estimating the arrival angle-polarization information of a shortwave skywave signal according to claim 1, characterized in that: The rank-deficient MUSIC algorithm comprises: Sampling the shortwave skywave signal using the shortwave three-component polarized receiving antenna array to obtain at least one snapshot sample point; generating an array output signal according to the at least one snapshot sample point, and calculating a maximum likelihood estimate of an autocovariance matrix of the array output signal; Based on the maximum likelihood estimation, eigendecomposing the autocovariance matrix of the array output signal to obtain a plurality of eigenvalues; Sorting the multiple eigenvalues ​​to generate a signal subspace and a noise subspace, and storing the matrix value of the noise subspace in a preset shared memory; Determine a first-level spectrum peak search range, a first-level search step value, a second-level spectrum peak search range, and a second-level search step value corresponding to the multi-level spectrum peak search operation; Based on the first-level spectrum peak search range, the first-level search step value, the second-level spectrum peak search range and the second-level search step value, and in combination with a preset spectral density algorithm, a multi-level spectrum peak search operation is performed to obtain the arrival angle estimation information and the polarization angle estimation information, wherein the arrival angle estimation information and the polarization angle estimation information include an azimuth angle estimation value, an elevation angle estimation value, a polarization auxiliary angle estimation value and a polarization phase angle estimation value.

4. The method for estimating the arrival angle-polarization information of a shortwave skywave signal according to claim 3, characterized in that: The corresponding array signal processing, information source number estimation and multi-level spectrum peak search operation are performed in a preset DSP processor to obtain the arrival angle estimation information and polarization angle estimation information of the shortwave skywave signal, including: Based on the first-level search step value, performing a first-level spectrum peak search operation within the first-level spectrum peak search range to obtain position information and amplitude information of all spectrum peaks within the first-level spectrum peak search range; Sorting all the spectrum peaks in descending order according to the amplitude information to obtain a first-level sorting result, and acquiring position information corresponding to the first K spectrum peaks of the first-level sorting result, so as to obtain a first-level spectrum peak search result of the shortwave skywave signal through the position information corresponding to the first K spectrum peaks; determining whether the first-level spectrum peak search result meets a preset accuracy requirement, wherein if the first-level spectrum peak search result meets the preset accuracy requirement, ending the first-level spectrum peak search operation, generating the arrival angle estimation information, and performing a polarization angle estimation operation according to the arrival angle estimation information to obtain polarization angle estimation information, wherein K is a positive integer; If the first-level spectrum peak search result does not meet the preset accuracy requirement, a second-level spectrum peak search operation is performed within the second-level spectrum peak search range according to the second-level search step value to obtain all spectrum peaks within the second-level spectrum peak search area, and all spectrum peaks within the second-level spectrum peak search area are sorted in descending order to obtain a second-level sorting result, and arrival angle information corresponding to the first K spectrum peaks of the second-level sorting result is obtained; Determine whether the arrival angle information meets the preset accuracy requirement, wherein if it does not meet the preset accuracy requirement, repeat the second-level spectrum peak search operation, otherwise end the second-level spectrum peak search operation, and obtain the arrival angle estimation information and the polarization angle estimation information.

5. The method for estimating the arrival angle-polarization information of a shortwave skywave signal according to claim 4, characterized in that: The multi-core parallel computing optimization strategy includes: Determine a plurality of overlapping interval critical values ​​corresponding to the first-level spectrum peak search range, and evenly divide the first-level spectrum peak search range into a plurality of search intervals according to the plurality of overlapping interval critical values; Performing a first-level spectrum peak search operation through multiple search intervals and a target multi-core processor to obtain a maximum spectrum peak of a master core and each slave core in the multi-core processor and an azimuth angle and a pitch angle corresponding to the maximum spectrum peak; Sending the maximum spectrum peak of each slave core and the azimuth and elevation angle corresponding to the maximum spectrum peak to the master core, so that the master core obtains a real spectrum peak according to the azimuth and elevation angle corresponding to the maximum spectrum peak of each slave core; Determine the angle of arrival corresponding to the true spectrum peak according to the azimuth angle and the elevation angle corresponding to the true spectrum peak, and judge whether the angle of arrival meets the preset range requirement; If the arrival angle meets the preset range requirement, a second-level spectrum peak search operation is performed according to the second-level search step value, and the matrix value of the noise subspace in the shared memory is called by the target multi-core processor, so that the target multi-core processor performs parallel calculations according to the matrix value of the noise subspace and the preset spectral density algorithm to obtain the arrival angle estimation information and the polarization angle estimation information.

6. The method for estimating the arrival angle-polarization information of a shortwave skywave signal according to claim 3, characterized in that: The mathematical expression of the preset spectral density algorithm is: Among them, θ k represents the azimuth of the kth shortwave skywave signal; represents the elevation angle of the k-th shortwave skywave signal; γ k represents the polarization auxiliary angle of the k-th shortwave skywave signal; η k represents the polarization phase angle of the k-th shortwave skywave signal; represents the steering vector of the array; h(γ, η) represents the polarization steering vector; U N represents the noise subspace; represents the conjugate transpose of the noise subspace; H represents the conjugate transpose.

7. An arrival angle-polarization information estimation device for a shortwave skywave signal, characterized in that: include: A receiving module, used to receive shortwave skywave signals using a preset shortwave three-component polarized receiving antenna array; The estimation module is used to perform corresponding array signal processing, source number estimation and multi-level spectrum peak search operations in a preset DSP processor based on the rank-deficient MUSIC algorithm and multi-core parallel computing optimization strategy to obtain the arrival angle estimation information and polarization angle estimation information of the shortwave skywave signal.

8. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for estimating the arrival angle-polarization information of a shortwave skywave signal according to any one of claims 1 to 5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The computer program is executed by a processor to implement the method for estimating the arrival angle-polarization information of a shortwave skywave signal as claimed in any one of claims 1 to 5.

10. A computer program product, comprising a computer program, characterized in that The computer program is executed to implement the method for estimating the arrival angle-polarization information of a shortwave skywave signal according to any one of claims 1 to 5.

Images