An anti-interference method, device and storage medium for low-orbit satellite navigation

Abstract

A low-orbit satellite navigation anti-interference method, device and storage medium. The low-orbit satellite navigation anti-interference method comprises the following steps: calculating a beam pointing output of an array antenna according to an array data vector of the array antenna; selecting a preset number of elements from the array antenna to form a nulling subarray and calculating an array data vector of the nulling subarray; calculating array weights of the nulling subarray according to the beam pointing output of the array antenna and the array data vector of the nulling subarray; and obtaining an array output of the array antenna according to the array weights of the nulling subarray. In the embodiment, a preset number of elements are randomly selected from the array antenna to form a nulling subarray, and array weights of the nulling subarray are calculated, so that the array weights of the array antenna are calculated according to the array weights of the nulling subarray, and adaptive nulling of an interference direction is realized without increasing the operation complexity, thereby greatly improving the anti-interference capability.

Description

TECHNICAL FIELD

[0001] The present application relates to, but is not limited to, satellite navigation technology, and in particular to a low-orbit satellite navigation anti-interference method, device and storage medium. BACKGROUND

[0002] In recent years, satellite navigation systems are developing from medium-high orbit constellations to mixed constellations of high, medium and low orbits. Low-orbit satellites (orbital height 200-2000 km) have the advantages of high signal ground power, high information rate, and diverse constellation geometry, which can make up for the shortcomings of current satellite navigation systems. In order to make full use of satellite resources, low-orbit satellite systems take into account both communication and navigation functions in their design. In the selection of service frequency bands, in order to take into account the needs of high-speed communication, the Ka band (the frequency range of the Ka band is 26.5-40 GHz) has become the mainstream. Compared with the L band (the frequency range of the L band is 1-2 GHz), the frequency of the Ka band is high, and the signal attenuates greatly during transmission, so high-gain parabolic antennas or phased array antennas are generally required for transceiver terminals.

[0003] In order to deal with the threat of electromagnetic interference, adaptive nulling anti-interference technology based on array antennas has been widely used in satellite navigation. This technology controls the gain pattern of the array antenna, forms nulls in the direction of interference and main beams in the direction of satellite signals, thereby achieving the purpose of filtering out interference and enhancing signals.

[0004] As satellite navigation systems develop towards low orbits and integrated communication and navigation, Ka phased array antennas will become one of the main antenna forms for transceiver terminals. However, Ka phased array antennas are generally composed of hundreds or even tens of thousands of antenna elements, and directly applying adaptive nulling anti-interference algorithms to Ka phased array antennas has extremely high computational complexity and is difficult to implement. In related technologies, high gain is obtained by beam pointing in the direction of the satellite using pre-stored array weights, but due to the computational complexity, it does not have the ability to adaptively null in the direction of interference, so its anti-interference ability is limited. SUMMARY

[0005] In view of this, the embodiments of the present application provide the following solutions.

[0006] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of protection of the claims.

[0007] The embodiments of the present application provide a low-orbit satellite navigation anti-interference method, comprising:

[0008] calculating a beam pointing output of the array antenna according to an array data vector of the array antenna;

[0009] randomly selecting a preset number of elements from the array antenna to form a nulling sub-array and calculating an array data vector of the selected nulling sub-array;

[0010] calculating array weights of the nulling sub-array according to the beam pointing output of the array antenna and the array data vector of the nulling sub-array;

[0011] obtaining an array output of the array antenna according to the array weights of the nulling sub-array.

[0012] In an exemplary instance, the calculating the beam pointing output of the array antenna according to the array data vector of the array antenna comprises:

[0013] The beam pointing output of the array antenna is calculated by using the following calculation formula:

[0014]

[0015] wherein d(t) is the beam pointing output of the array antenna at t moment, a i is a steering vector of a target signal, and x(t) is the array data vector of the array antenna.

[0016] In an exemplary instance, the array data vector of the array antenna is represented by the following formula:

[0017]

[0018] wherein x(t)=[x1(t) x2(t) … x N (t)] T is an N-dimensional vector, each row corresponding to an element, (·) T represents a transposition operation, s k (t) is the kth satellite signal received by a reference receiving point, a k is a steering vector of a corresponding target signal, j m (t) is the mth interference received by the reference point, b m is a corresponding interference steering vector, and n(t) is an N-dimensional additive white Gaussian noise vector.

[0019] In an exemplary instance, the randomly selecting a preset number of elements from the array antenna to form a nulling sub-array and calculating an array data vector of the selected nulling sub-array comprises:

[0020] L elements are randomly selected from the N elements of the array antenna to form the nulling sub-array, wherein L

[0021] The array data vector of the selected nulling sub-array is calculated by using the following calculation formula:

[0022] z(t) = Qx(t);

[0023] wherein z(t) is an array data vector of the nulling subarray, Q is an L-dimensional column vector, is an L by N matrix, wherein e j = [0,..,0,1,0,...,0] T denotes a unit column vector with the jth element being 1 and other elements being 0, and the vector subscripts n1, n2,..., nL denote the element number of the nulling subarray, and x(t) is an array data vector of the array antenna.

[0024] In an exemplary instance, the number of elements constituting the nulling subarray is selected according to the number of interferences to be suppressed.

[0025] The array weight of the nulling subarray is calculated according to the beam pointing output of the array antenna and the array data vector of the nulling subarray, comprising:

[0026] The array weight of the nulling subarray is calculated by using the following calculation formula:

[0027]

[0028] wherein w sub is the array weight of the nulling subarray, R z is the autocorrelation matrix of the array data vector z(t) of the nulling subarray, is the inverse matrix of R z , and r zd is the cross-correlation function of the array data vector z(t) of the nulling subarray and the beam pointing output d(t) of the array antenna.

[0029] In an exemplary instance, the array output of the array antenna is obtained according to the array weight of the nulling subarray, comprising:

[0030] The array weight of the array antenna is calculated according to the array weight of the nulling subarray, and the array output of the array antenna is calculated according to the array weight of the array antenna.

[0031] In an exemplary instance, the array weight of the array antenna is calculated according to the array weight of the nulling subarray, comprising:

[0032] The array weight of the array antenna is calculated by using the following calculation formula:

[0033]

[0034] wherein w is the array weight of the array antenna, a i is the steering vector of the target signal, and Q His a conjugate transpose of Q matrix, R z is an autocorrelation matrix of array data vector z(t) of the nulling subarray, is an inverse matrix of R z is an autocorrelation matrix of array data vector z(t) of the nulling subarray, zd is a cross-correlation function of array data vector z(t) of the nulling subarray and beam pointing output d(t) of the array antenna;

[0035] computing the array output of the array antenna according to array weights of the array antenna, comprising:

[0036] computing the array output of the array antenna by using the following calculation formula:

[0037] y(t)=w H x(t);

[0038] wherein w H is a conjugate transpose of array weights of the array antenna, and x(t) is an array data vector of the array antenna.

[0039] The embodiment of the present application further provides a low-orbit satellite navigation anti-interference device, comprising a processor and a computer readable storage medium, and the computer readable storage medium has instructions stored therein, and when the instructions are executed by the processor, the low-orbit satellite navigation anti-interference method is realized.

[0040] The embodiment of the present application further provides a computer readable storage medium, and the computer readable storage medium has a computer program stored thereon, and the computer program is executed by a processor to realize the steps of the method.

[0041] The low-orbit satellite navigation anti-interference method, device and storage medium are used for computing the beam pointing output of the array antenna according to the array data vector of the array antenna, selecting a preset number of array elements from the array antenna to form a nulling subarray and computing the array data vector of the nulling subarray, computing the array weights of the nulling subarray according to the beam pointing output of the array antenna and the array data vector of the nulling subarray, and obtaining the array output of the array antenna according to the array weights of the nulling subarray. According to the embodiment of the present application, a preset number of array elements are randomly selected from the array antenna to form a nulling subarray and the array weights of the nulling subarray are computed, so that the array weights of the array antenna are computed according to the array weights of the nulling subarray, the adaptive nulling of the interference direction is realized without increasing the operation complexity, and the anti-interference capability is greatly improved.

[0042] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the following or can be learned by practice of the present application. The objects and other advantages of the present application can be achieved and obtained by means of the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0043] The accompanying drawings are included to provide a further understanding of the technical solutions of the present application, constitute a part of the specification and are used to explain the technical solutions of the present application together with the embodiments of the present application, and do not constitute a limitation on the technical solutions of the present application.

[0044] Figure 1 A schematic diagram of the anti-interference method for the low-orbit satellite navigation of the embodiment of the present application;

[0045] Figure 2 A gain pattern of the Ka phased array antenna of the embodiment of the present application. DETAILED DESCRIPTION

[0046] The present application describes a plurality of embodiments, but the description is exemplary rather than limiting, and it is obvious to those skilled in the art that there can be more embodiments and implementation schemes within the scope of the embodiments described in the present application. Although many possible combinations of features are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment can be used in combination with any other feature or element of any other embodiment, or can replace any other feature or element of any other embodiment.

[0047] The present application includes and contemplates combinations of features and elements known to those skilled in the art. The embodiments, features and elements disclosed in the present application can also be combined with any conventional features or elements to form a unique inventive scheme defined by the claims. Any feature or element of any embodiment can also be combined with features or elements from other inventive schemes to form another unique inventive scheme defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in the present application can be implemented alone or in any appropriate combination. Therefore, the embodiments are not limited other than as set forth in the claims and their equivalents. In addition, various modifications and changes can be made within the scope of protection of the appended claims.

[0048] Moreover, in describing representative embodiments, the specification can have presented the method and / or process as a particular sequence of steps. However, to the extent that the method or process depends on the particular order of steps, this description should not be construed as limiting since other steps can be performed in other sequences and / or omitted from the method or process. Therefore, the particular order of steps presented in the specification should not be construed as a limitation on the claims. Furthermore, the claims should not be limited to the steps of the method and / or process in the order presented in the specification. Other steps can be added to the method and / or process, and / or the order of steps can be changed, without departing from the spirit and scope of the present embodiments.

[0049] The embodiments of the present application provide a low-orbit satellite navigation anti-interference method, which comprises the following steps of: Figure 1 as shown in the drawings, comprising:

[0050] Step 101, calculating the beam pointing output of the array antenna according to the array data vector of the array antenna;

[0051] Step 102, randomly selecting a preset number of elements from the array antenna to form a nulling subarray and calculating the array data vector of the selected nulling subarray;

[0052] Step 103, calculating the array weight of the nulling subarray according to the beam pointing output of the array antenna and the array data vector of the nulling subarray;

[0053] Step 104, obtaining the array output of the array antenna according to the array weight of the nulling subarray.

[0054] In an exemplary instance, the step 101 of calculating the beam pointing output of the array antenna according to the array data vector of the array antenna comprises:

[0055] The beam pointing output of the array antenna is calculated by using the following calculation formula:

[0056]

[0057] wherein d(t) is the beam pointing output of the array antenna at t moment, a i is the steering vector of the target signal (the i-th satellite signal), which is also the array weight of the beam pointing output, is an N-dimensional column vector, x(t) is the array data vector of the array antenna, and is an N-dimensional column vector.

[0058] In an exemplary instance, the steering vector of the target signal is determined by the element position of the array antenna and the incident angle of the target signal, and contains all the spatial information of the incident signal.

[0059] In an exemplary instance, the array data vector of the array antenna can be represented by the following formula:

[0060]

[0061] where x(t)=[x1(t) x2(t) … xN(t)]T N T is an N-dimensional vector, each row corresponds to an array element respectively, T denotes the transpose operation, s k (t) is the kth satellite signal received by the reference receiving point, a k is the corresponding target signal steering vector, j m (t) is the mth interference received by the reference point, b m is the corresponding interference steering vector, and n(t) is an N-dimensional additive white Gaussian noise vector. It is assumed that each noise component is independent and identically distributed with mean 0 and variance σ 2 .

[0062] In an exemplary embodiment, the step 102 of selecting a preset number of array elements from the array antenna to form a nulling subarray and calculating the array data vector of the selected nulling subarray comprises:

[0063] Randomly selecting L array elements from the N array elements of the array antenna to form a nulling subarray, where L

[0064] The number L of array elements forming the nulling subarray can be selected according to the number of interferences to be suppressed, for example, it can take values of 4, 7, 10, etc.

[0065] The array data vector of the nulling subarray is calculated using the following calculation formula:

[0066] z(t)=Qx(t);

[0067] where z(t) is the array data vector of the nulling subarray, and is an L-dimensional column vector, is an L-by-N matrix, where e j =[0,..,0,1,0,...,0] T denotes a unit column vector with the jth element being 1 and other elements being 0, and the vector subscripts n1, n2, …, nL represent the array element numbers of the nulling subarray, and x(t) is the array data vector of the array antenna.

[0068] In an exemplary embodiment, the step 103 of calculating the array weight of the nulling subarray according to the beam pointing output of the array antenna and the array data vector of the nulling subarray comprises:

[0069] The array weight of the nulling subarray is calculated using the following calculation formula:

[0070] ​

[0071] wherein w sub is the array weight of the nulling subarray.

[0072] R z is the autocorrelation matrix of the array data vector z(t) of the nulling subarray, is an L-dimensional square matrix, and is obtained by using the following calculation formula:

[0073] R z = E[z(t)z H (t)]

[0074] is the inverse matrix of R z

[0075] r zd is the cross-correlation function of the array data vector z(t) of the nulling subarray and the beam pointing output d(t) of the array antenna, is an L-dimensional square matrix, and is obtained by using the following calculation formula:

[0076] r zd = E[z(t)d H (t)]

[0077] In an exemplary instance, the step 104 of obtaining the array output of the array antenna according to the array weight of the nulling subarray comprises:

[0078] calculating the array weight of the array antenna according to the array weight of the nulling subarray; and calculating the array output of the array antenna according to the array weight of the array antenna.

[0079] In an exemplary instance, the array weight of the array antenna is calculated by using the following calculation formula:

[0080]

[0081] wherein w is the array weight of the array antenna, a i is the steering vector of the target signal, Q H is the conjugate transpose of the Q matrix, R z is the autocorrelation matrix of the array data vector z(t) of the nulling subarray, is the inverse matrix of R z , and r zd is the cross-correlation function of the array data vector z(t) of the nulling subarray and the beam pointing output d(t) of the array antenna.

[0082] Since the most complex part of the operation in the array weight of the array antenna is the inverse operation of the matrix R z , that is, the inverse operation of the matrix R z ​It is an L-dimensional square array, whose dimension is much smaller than the total number of array elements N of the array antenna. In the embodiments of this application, a preset number of array elements are randomly selected from the array antenna to form a nulling subarray and the array weight of the nulling subarray is calculated. Then, the array weight of the array antenna is calculated based on the array weight of the nulling subarray. Without increasing the computational complexity, adaptive nulling in the interference direction is achieved, which greatly improves the anti-interference capability.

[0083] The array output of the antenna array is calculated using the following formula:

[0084] y(t)=w H x(t);

[0085] Among them, w H Let x(t) be the conjugate transpose of the array weights of the array antenna, and let x(t) be the array data vector of the array antenna.

[0086] In one exemplary instance, assuming a Ka phased array antenna consists of 100 antenna elements (i.e., N = 100), the target signal is incident from an 80-degree elevation angle, and an electromagnetic interference is incident from a 5-degree elevation angle, with interference power 40 dB higher than thermal noise, this embodiment takes 10 elements (i.e., L = 10, numbered 91 to 100) selected from the 100 elements to form a nulling subarray as an example. Using the above-described low-Earth orbit satellite navigation anti-interference method, the gain pattern of the Ka phased array antenna in this embodiment is as follows. Figure 2 As shown, a main beam is formed in the direction of the target signal with a beam gain of approximately 20 dB. Simultaneously, a null is formed in the direction of electromagnetic interference with a depth of 67 dB. This enhances the target signal while achieving adaptive interference filtering. Regarding computational complexity, the computational complexity of this embodiment is O(L³) = O(10³), while the computational complexity of the traditional adaptive zero-adjustment anti-interference method is O(N³) = O(10⁶), significantly higher than the aforementioned method. The beam pointing method using pre-stored array weights in related technologies has a computational complexity of O(N) = O(10²), which, although the lowest, lacks adaptive zero-adjustment capability and has limited anti-interference ability.

[0087] On the other hand, embodiments of the present invention also provide a low-Earth orbit satellite navigation anti-interference device, including a processor and a computer-readable storage medium, wherein the computer-readable storage medium stores instructions, and when the instructions are executed by the processor, the above-mentioned low-Earth orbit satellite navigation anti-interference method is implemented.

[0088] On the other hand, embodiments of the present invention also provide a computer-readable storage medium storing a computer program thereon, wherein the computer program, when executed by a processor, implements the steps of the above-described low-orbit satellite navigation anti-interference method.

[0089] The low-orbit satellite navigation anti-interference method, device and storage medium calculate the beam pointing output of the array antenna according to the array data vector of the array antenna; select a preset number of elements from the array antenna to form a nulling subarray and calculate the array data vector of the nulling subarray; calculate the array weight of the nulling subarray according to the beam pointing output of the array antenna and the array data vector of the nulling subarray; and obtain the array output of the array antenna according to the array weight of the nulling subarray. In the embodiment of the application, a preset number of elements are randomly selected from the array antenna to form a nulling subarray and the array weight of the nulling subarray is calculated, so that the array weight of the array antenna is calculated according to the array weight of the nulling subarray, the adaptive nulling of the interference direction is realized without increasing the operation complexity, and the anti-interference capability of the Ka phased array terminal is greatly improved.

[0090] Those of ordinary skill in the art understand that all or some of the steps in the methods disclosed above and the functional modules / units in the systems and devices can be implemented as software, firmware, hardware and appropriate combinations thereof. In hardware implementation, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component can have multiple functions, or one function or step can be performed by several physical components in cooperation. Some or all of the components can be implemented as software executed by a processor such as a digital signal processor or a microprocessor, or as hardware, or as an integrated circuit such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transitory media). As known to those of ordinary skill in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, as known to those of ordinary skill in the art, communication media typically includes computer readable instructions, data structures, program modules or other data in modulated data signals such as carrier waves or other transport mechanisms, and can include any information delivery medium.

Claims

1. An anti-interference method for low-Earth orbit satellite navigation, comprising: The beam pointing output of the array antenna is calculated based on the array data vector of the array antenna; A preset number of array elements are randomly selected from the array antenna to form a nulling subarray, and the array data vector of the selected nulling subarray is calculated. The array weights of the nulling subarray are calculated based on the beam pointing output of the array antenna and the array data vector of the nulling subarray. The array weights of the array antennas are calculated based on the array weights of the nulling subarray. The array output of the array antenna is calculated based on the array weights of the array antenna; The step of calculating the array weights of the array antenna based on the array weights of the nulling subarray includes: The array weights of the array antenna are calculated using the following formula: in, The array weights are the array weights of the antenna array. The steering vector of the target signal. for The conjugate transpose of a matrix. Let L be a matrix with N rows and N columns, where... Let n1, n2, ..., nL be a unit column vector whose j-th element is 1 and all other elements are 0. The vector indices n1, n2, ..., nL represent the element numbers of the zeroing subarray. The array data vector of the zeroing subarray The autocorrelation matrix, for The inverse matrix, The array data vector of the zeroing subarray Beam pointing output of the array antenna The cross-correlation function, The array weights of the zeroing subarray; Calculating the array output of the array antenna based on the array weights of the array antenna includes: The array output of the array antenna is calculated using the following formula: ； in, This is the conjugate transpose of the array weights of the array antenna. This is the array data vector of the array antenna.

2. The anti-interference method for low-Earth orbit satellite navigation according to claim 1, wherein, The step of calculating the beam pointing output of the array antenna based on the array data vector of the array antenna includes: The beam pointing output of the array antenna is calculated using the following formula: ； in, for The beam pointing output of the array antenna at time [time]. The steering vector of the target signal. is the array data vector of the array antenna.

3. The anti-interference method for low-Earth orbit satellite navigation according to claim 1, wherein, The array data vector of the array antenna is represented by the following formula: ； in, It is an N-dimensional vector, with each row corresponding to a matrix element. This represents the transpose operation. For the reference receiving point, the k-th satellite signal, It is the steering vector of the corresponding target signal. It is the m-th interference received by the reference point. For the corresponding interference steering vector, It is an N-dimensional additive white Gaussian noise vector. K This represents the total number of satellite signals received by the reference receiving point. M This represents the total number of interferences received by the reference point.

4. The anti-interference method for low-Earth orbit satellite navigation according to any one of claims 1 to 3, wherein, The step of randomly selecting a preset number of array elements from the array antenna to form a nulling subarray and calculating the array data vector of the selected nulling subarray includes: From the N array elements of the array antenna, L array elements are randomly selected to form the nulling subarray, where L < N; The array data vector of the selected zeroing subarray is calculated using the following formula: ； in, Let be the array data vector of the zeroing subarray, which is an L-dimensional column vector. This is the array data vector of the array antenna.

5. The anti-interference method for low-Earth orbit satellite navigation according to claim 4, wherein, The number of array elements constituting the zeroing subarray is selected according to the number of interferences to be suppressed.

6. The anti-interference method for low-Earth orbit satellite navigation according to claim 4, wherein, The step of calculating the array weights of the nulling subarray based on the beam pointing output of the array antenna and the array data vector of the nulling subarray includes: The array weights of the zeroing subarray are calculated using the following formula: ； in, The array data vector of the zeroing subarray The autocorrelation matrix, for The inverse matrix, The array data vector of the zeroing subarray Beam pointing output of the array antenna The cross-correlation function.

7. An anti-interference device for low-Earth orbit satellite navigation, comprising a processor and a computer-readable storage medium, wherein the computer-readable storage medium stores instructions that, when executed by the processor, implement the anti-interference method for low-Earth orbit satellite navigation as described in any one of claims 1 to 6.

8. A computer-readable storage medium having a computer program stored thereon, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 6.

Images