A positioning method, device and storage medium based on low-orbit satellite opportunistic signals

Abstract

The present application discloses a positioning method, device, and storage medium based on low-orbit satellite opportunistic signals, which relates to the field of satellite technology. The method includes: extracting corresponding signal arrival angle information and Doppler frequency shift information according to the opportunistic signals of low-orbit satellites at the current epoch; determining the orbit information of low-orbit satellites at the current epoch according to a preset two-line element set (TLE) file of satellites and a satellite orbit prediction model; when the number of low-orbit satellites is not less than a preset number of satellites, generating rough positioning information of the receiver according to the signal arrival angle information and the orbit information, and using the rough positioning information as the initial value for iterative calculation in the Doppler positioning process to perform iterative calculation to determine the final positioning information of the receiver; and when the number of low-orbit satellites is less than the preset number of satellites, calculating the final positioning information of the receiver according to the signal arrival angle information, the Doppler frequency shift information, and the orbit information.

Description

Technical Field

[0001] The present application relates to the field of satellite technology, and in particular to a positioning method, device and storage medium based on low-earth orbit satellite opportunity signals. Background Art

[0002] At present, low-earth orbit satellite positioning technology has been applied in many fields such as backup navigation, military operations, auxiliary agricultural machinery management, and helping to achieve integration of communication, navigation and remote sensing. The opportunity signal positioning method has higher resource utilization rate because it does not require a pre-set signal system and additional infrastructure construction, and can be applied to various environments, which has received extensive attention in the field.

[0003] Low-earth orbit satellite positioning technology has broad application prospects, but it also faces many challenges in the development process. First, the high dynamic and non-cooperative characteristics of low-earth orbit satellites make it difficult to extract pseudo-range and carrier phase observations. Currently, most low-earth orbit satellite positioning technologies use the Doppler positioning principle, and the observations are relatively single. When the number of low-earth orbit satellites used for observation is small, instantaneous positioning cannot be achieved in a single epoch, and the positioning accuracy is also limited. Usually, the positioning accuracy can only reach the ten-meter level. Second, the iterative solution in the Doppler positioning process depends highly on the initial value, and the initial value will affect the number of iterations required for the iterative solution and the positioning accuracy.

[0004] Common ideas to solve the problem of limited accuracy are to improve the Doppler observation accuracy, perform differential positioning, or carry multiple sensors for combined positioning. To improve the Doppler observation accuracy, specific observation extraction methods usually need to be selected according to the target signal system. For example, the frequency-domain sliding window estimation method for Starlink beacon signals and the parallel code phase search and capture algorithm for Globalstar signals; differential positioning requires adding a base station with a known position, and by subtracting the observations of the receiver and the base station in the same epoch, some errors can be eliminated to improve the positioning accuracy; combined positioning requires additional sensors, such as altimeters and inertial navigation systems. The low-earth orbit satellite positioning system and other positioning systems cooperate through a Kalman filter to improve the positioning accuracy.

[0005] When using Doppler frequency shift positioning, the positioning result is limited by the number of low-earth orbit satellites. When the number of observed satellites is less than four, the requirement of instantaneous positioning cannot be met, and it is necessary to wait for multiple epochs to integrate the Doppler. Although low-earth orbit satellites have a higher moving speed compared to medium and high-earth orbit satellites, a certain amount of time still needs to be accumulated to form sufficient geometric motion, and this process will be affected by the satellite-ground clock difference. In addition, the Doppler positioning solution process cannot avoid relying on the initial value of the target position. When the initial value is missing, the number of iterative solutions will increase significantly.

[0006] Publication number: CN119001789A, title: Doppler frequency shift positioning method, device, equipment and medium based on low-earth orbit satellites. The method includes: receiving visible low-earth orbit satellite ephemeris data; calculating the position of each low-earth orbit satellite based on the received satellite ephemeris data; calculating the sub-satellite point according to the satellite position and determining its visible range with the sub-satellite point as the center; taking the intersection of the visible ranges of multiple low-earth orbit satellites and evenly taking points within the intersection as the initial positioning candidate points; using each initial positioning candidate point as the initial positioning point of the Doppler frequency shift observation equation, calculating the user position by using the least squares method, and recording the magnitude of the positioning residual; traversing to obtain the minimum value of the positioning residuals of all initial positioning candidate points, determining whether the minimum value of the residuals is less than the residual threshold, if it is less, the convergence is successful, and taking the user position corresponding to the minimum value of the residuals as the positioning result of the user.

[0007] Publication number: CN101855566A, title: System for determining location via a network. The system includes a base station receiver having a clock and a known position, which determines the distance to a transmitter, obtains a sample sequence of opportunistic signals, and time-marks the sequence with the reception time, based on the calculated distance and the calculated transmission time or both. The base station receiver sends the time-marked sequence to a remote receiver and optionally sends the calculated distance. Given that the remote receiver stores and time-marks samples of the opportunistic signals, correlates the time-marked sequence with the stored samples, and calculates a time offset as the difference between the reception time at the remote receiver and either one of the following two: the reception time at the base station receiver and the calculated transmission time at the base station receiver. The remote receiver calculates the position based on the time offset and optionally the distance provided by the base station receiver. The altitude of the remote receiver can be calculated as part of the position calculation, can be determined iteratively based on restricting the Z coordinate to the average altitude, or can be determined based on the difference in air pressure sensor readings at the base station and the remote receiver.

[0008] Regarding the technical problems in the above-mentioned prior art that the positioning result of Doppler frequency shift positioning is restricted by the number of low-earth orbit satellites, the instantaneous positioning is restricted by the number of observed satellites, and the lack of initial values in the Doppler positioning solution process leads to an increase in the number of iterative solutions, no effective solution has been proposed yet. Summary of the Invention

[0009] Embodiments of the present application provide a positioning method, device and storage medium based on low-earth orbit satellite opportunistic signals to at least solve the technical problems in the prior art that the positioning result of Doppler frequency shift positioning is restricted by the number of low-earth orbit satellites, the instantaneous positioning is restricted by the number of observed satellites, and the lack of initial values in the Doppler positioning solution process leads to an increase in the number of iterative solutions.

[0010] According to one aspect of the embodiments of the present application, a positioning method based on opportunity signals of low-earth orbit satellites is provided, including: extracting corresponding signal arrival angle information and Doppler frequency shift information according to the opportunity signals of low-earth orbit satellites in the current epoch, where the signal arrival angle information is used to indicate the positional relationship between the low-earth orbit satellite and the receiver, and the Doppler frequency shift information is used to indicate the relative motion information between the low-earth orbit satellite and the receiver; determining the orbit information of the low-earth orbit satellite in the current epoch according to a preset two-line element set file of the satellite and a satellite orbit prediction model; in the case where the number of low-earth orbit satellites is not less than a preset number of satellites, generating rough positioning information of the receiver according to the signal arrival angle information and the orbit information, and using the rough positioning information as the initial value for iterative calculation in the Doppler positioning process to perform iterative calculation to determine the final positioning information of the receiver; and in the case where the number of low-earth orbit satellites is less than the preset number of satellites, calculating the final positioning information of the receiver according to the signal arrival angle information, the Doppler frequency shift information, and the orbit information.

[0011] According to another aspect of the embodiments of the present application, a positioning device based on opportunity signals of low-earth orbit satellites is further provided, including: an information extraction module, configured to extract corresponding signal arrival angle information and Doppler frequency shift information according to the opportunity signals of low-earth orbit satellites in the current epoch, where the signal arrival angle information is used to indicate the positional relationship between the low-earth orbit satellite and the receiver, and the Doppler frequency shift information is used to indicate the relative motion information between the low-earth orbit satellite and the receiver; an information determination module, configured to determine the orbit information of the low-earth orbit satellite in the current epoch according to a preset two-line element set file of the satellite and a satellite orbit prediction model; a first positioning information determination module, configured to, in the case where the number of low-earth orbit satellites is not less than a preset number of satellites, generate rough positioning information of the receiver according to the signal arrival angle information and the orbit information, and use the rough positioning information as the initial value for iterative calculation in the Doppler positioning process to perform iterative calculation to determine the final positioning information of the receiver; and a second positioning information determination module, configured to, in the case where the number of low-earth orbit satellites is less than the preset number of satellites, calculate the final positioning information of the receiver according to the signal arrival angle information, the Doppler frequency shift information, and the orbit information.

[0012] According to another aspect of the embodiments of the present application, a positioning method based on low-earth orbit satellite opportunistic signals is further provided, including: a processor; and a memory connected to the processor for providing instructions for the processor to process the following steps: extracting corresponding signal arrival angle information and Doppler frequency shift information according to the opportunistic signals of low-earth orbit satellites in the current epoch, where the signal arrival angle information is used to indicate the positional relationship between the low-earth orbit satellite and the receiver, and the Doppler frequency shift information is used to indicate the relative motion information between the low-earth orbit satellite and the receiver; determining the orbit information of the low-earth orbit satellite in the current epoch according to a preset two-line element set (TLE) file of the satellite and a satellite orbit prediction model; when the number of low-earth orbit satellites is not less than a preset number of satellites, generating rough positioning information of the receiver according to the signal arrival angle information and the orbit information, and using the rough positioning information as the initial value for iterative calculation in the Doppler positioning process to perform iterative calculation to determine the final positioning information of the receiver; and when the number of low-earth orbit satellites is less than the preset number of satellites, calculating the final positioning information of the receiver according to the signal arrival angle information, the Doppler frequency shift information, and the orbit information.

[0013] According to another aspect of the embodiments of the present application, a computer-readable storage medium is further provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0014] In the embodiments of the present application, the computing device sets two different positioning methods according to the number of low-earth orbit satellites, including a serial fusion method and a parallel fusion method, so as to be flexibly applied according to the number of low-earth orbit satellites, improving the flexibility and applicability of the system. And when the number of low-earth orbit satellites is small, the equation for positioning according to the signal arrival angle information and the equation for positioning according to the Doppler frequency shift information are used to calculate the final positioning information of the receiver simultaneously, increasing the number of observables, thereby reducing the dependence on the initial value of the target position, reducing the number of iterative calculations, and accelerating the positioning speed. And when the number of low-earth orbit satellites is large, the rough positioning information of the receiver is first calculated according to the signal arrival angle information as the initial value for the Doppler positioning calculation process for calculating the final positioning information of the receiver, so as to limit the initial value within a reasonable range, reduce the number of iterative calculations, and improve the calculation speed. Furthermore, the technical problems in the prior art that the positioning result of Doppler frequency shift positioning is limited by the number of low-earth orbit satellites, the instantaneous positioning is limited by the number of observed satellites, and the lack of the initial value in the Doppler positioning calculation process leads to an increase in the number of iterative calculations are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments and descriptions thereof of the present application are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

[0016] Figure 1 It is a hardware structure block diagram of a computing device for implementing the method described in Embodiment 1 of the present application;

[0017] Figure 2 It is a schematic flowchart of a positioning method based on low-earth orbit satellite opportunity signals according to the first aspect of Embodiment 1 of the present application;

[0018] Figure 3 It is a schematic diagram of a positioning device based on low-earth orbit satellite opportunity signals according to Embodiment 2 of the present application; and

[0019] Figure 4 It is a schematic diagram of a positioning device based on low-earth orbit satellite opportunity signals according to Embodiment 3 of the present application. Detailed implementation manners

[0020] In order to enable those skilled in the art to better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0021] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order different from those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily need to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0022] Embodiment 1

[0023] According to this embodiment, a method embodiment of a positioning method based on low-earth orbit satellite opportunity signals is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order from that here.

[0024] The method embodiments provided in this embodiment may be executed in a mobile terminal, a computer terminal, a server, or similar computing devices. Figure 1 The following shows a hardware block diagram of a computing device for implementing a positioning method based on low-earth orbit satellite opportunistic signals. As Figure 1 shown, the computing device may include one or more processors (the processor may include, but is not limited to, a processing device such as a microprocessor MCU or a programmable logic device FPGA), a memory for storing data, and a transmission device for communication functions. In addition, it may further include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of the I / O interface), a network interface, a power supply, and / or a camera. Those of ordinary skill in the art can understand that Figure 1 the structure shown is only schematic and does not limit the structure of the above-mentioned electronic device. For example, the computing device may further include more or fewer components than Figure 1 shown, or have a different configuration from Figure 1 shown.

[0025] It should be noted that the above one or more processors and / or other data processing circuits are generally referred to as "data processing circuits" in this article. The data processing circuit may be embodied in software, hardware, firmware, or any combination thereof, in whole or in part. In addition, the data processing circuit may be a single independent processing module, or be incorporated in whole or in part into any one of other elements in the computing device. As involved in the embodiments of the present application, the data processing circuit is a kind of processor control (such as the selection of a variable resistor terminal path connected to an interface).

[0026] The memory can be used to store software programs and modules of application software, such as the program instructions / data storage device corresponding to the positioning method based on low-earth orbit satellite opportunistic signals in the embodiments of the present application. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory, that is, implements the positioning method of the application program based on low-earth orbit satellite opportunistic signals. The memory may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memories. In some instances, the memory may further include a memory remotely located relative to the processor, and these remote memories can be connected to the computing device through a network. Examples of the above network include, but are not limited to, the Internet, an enterprise intranet, a local area network, a mobile communication network, and combinations thereof.

[0027] The transmission device is used to receive or send data via a network. Specific examples of the above-mentioned network may include a wireless network provided by a communication provider of a computing device. In one example, the transmission device includes a network adapter (Network Interface Controller, NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device can be a Radio Frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0028] The display can be, for example, a touch-screen liquid crystal display (LCD), which enables a user to interact with the user interface of the computing device.

[0029] It should be noted here that in some alternative embodiments, the above Figure 1 shown computing device may include hardware elements (including circuits), software elements (including computer code stored on a computer-readable medium), or a combination of both hardware elements and software elements. It should be pointed out that Figure 1 is only an example of a specific specific instance and is intended to show the types of components that may exist in the above-mentioned computing device.

[0030] Under the above operating environment, according to the first aspect of this embodiment, a positioning method based on low-earth orbit satellite opportunity signals is provided, and this method is implemented by Figure 1 the computing device shown in. Figure 2 shows a schematic flow diagram of this method. Referring to Figure 2 shown, this method includes:

[0031] S202: Extract the corresponding signal arrival angle information and Doppler frequency shift information according to the opportunity signal of the low-earth orbit satellite in the current epoch, where the signal arrival angle information is used to indicate the positional relationship between the low-earth orbit satellite and the receiver, and the Doppler frequency shift information is used to indicate the relative motion information between the low-earth orbit satellite and the receiver;

[0032] S204: Determine the orbit information of the low-earth orbit satellite in the current epoch according to the preset two-line element set file of the satellite and the satellite orbit prediction model;

[0033] S206: When the number of low-earth orbit satellites is not less than the preset number of satellites, generate rough positioning information of the receiver according to the signal arrival angle information and the orbit information, and use the rough positioning information as the initial value of the iterative solution in the Doppler positioning process to perform iterative solution to determine the final positioning information of the receiver; and

[0034] S208: When the number of low-earth orbit (LEO) satellites is less than a preset number of satellites, calculate the final positioning information of the receiver based on the angle of arrival (AoA) information, Doppler shift information, and orbit information.

[0035] Specifically, the computing device acquires the opportunistic signals of multiple LEO satellites at the current epoch. Among them, there are N several LEO satellites, all of which are observable satellites. Then the computing device processes the opportunistic signals of the multiple LEO satellites to extract the AoA information and Doppler shift information corresponding to each opportunistic signal. The AoA information is used to indicate the positional relationship between the LEO satellite and the receiver, and the Doppler shift information is used to indicate the relative motion information between the LEO satellite and the receiver.

[0036] Furthermore, the computing device is pre-set with a satellite orbit prediction model for predicting the orbit information of satellites, and also pre-sets a two-line element set (TLE) data file corresponding to the LEO satellites. The satellite orbit prediction model can be, for example, a simplified general perturbation model, and the TLE data file is a publicly available file for recording satellite orbit parameters. Then the computing device inputs the TLE data files of each LEO satellite into the satellite orbit prediction model, and outputs the orbit information corresponding to each LEO satellite through the satellite orbit prediction model. The orbit information includes the three-dimensional position coordinates and three-dimensional velocity of the LEO satellite.

[0037] Furthermore, the computing device is pre-set with two methods for determining the final position information of the receiver, namely the serial fusion method and the parallel fusion method. Then the computing device determines whether the number of LEO satellites is less than the preset number of satellites. For example, the preset number of satellites is 4. Thus, when the number of LEO satellites is not less than the preset number of satellites (i.e., 4), the computing device uses the serial fusion method to determine the final positioning information of the receiver. When the number of LEO satellites is less than the preset number of satellites (i.e., 4), the computing device uses the parallel fusion method to determine the final positioning information of the receiver.

[0038] More specifically, when the number of LEO satellites is not less than the preset number of satellites, for the serial fusion method, the computing device generates the rough positioning information of the receiver based on the AoA information and the orbit information, and uses the rough positioning information as the initial value for iterative solution in the Doppler positioning process to determine the final positioning information of the receiver.

[0039] In the case where the number of low-earth orbit (LEO) satellites is less than the preset number of satellites, for the parallel fusion method, the computing device fuses the equation for positioning based on the angle of arrival (AoA) information of the signal and the equation for positioning based on the Doppler shift information, so as to use the equation for positioning based on the AoA information of the signal and the equation for positioning based on the Doppler shift information to perform calculations simultaneously to determine the final positioning information of the receiver.

[0040] As described in the background art, when using Doppler shift positioning, the positioning result is limited by the number of LEO satellites. When the number of LEO satellites is less than four, the requirement for instantaneous positioning cannot be met, and it is necessary to wait for multiple epochs to integrate the Doppler. Although LEO satellites have a higher moving speed compared to medium and high-earth orbit satellites, a certain amount of time still needs to be accumulated to form sufficient geometric motion, and this process will be affected by the satellite-ground clock offset. In addition, the Doppler positioning solution process cannot avoid relying on the initial value of the target position. When the initial value is missing, the number of iterative solutions will increase significantly.

[0041] To address the above technical problems, through the technical solution of the embodiments of the present application, the computing device sets two different positioning methods according to the number of LEO satellites, including a serial fusion method and a parallel fusion method, so as to flexibly apply the number of LEO satellites, improving the flexibility and applicability of the system. And in the case where the number of LEO satellites is small, the equation for positioning based on the AoA information of the signal and the equation for positioning based on the Doppler shift information are used to calculate the final positioning information of the receiver simultaneously, increasing the number of observables, thereby reducing the dependence on the initial value of the target position, reducing the number of iterative solutions, and accelerating the positioning speed. And when the number of LEO satellites is large, this technical solution will first calculate the rough positioning information of the receiver based on the AoA information as the initial value for the Doppler positioning solution process for calculating the final positioning information of the receiver, thereby restricting the initial value within a reasonable range, reducing the number of iterative solutions, and improving the calculation speed. Thus, the technical problems existing in the prior art, such as the positioning result of Doppler shift positioning being limited by the number of LEO satellites, the instantaneous positioning being limited by the number of observed satellites, and the increase in the number of iterative solutions due to the lack of the initial value in the Doppler positioning solution process, are solved.

[0042] Optionally, the operation of extracting the corresponding AoA information and Doppler shift information according to the opportunity signal of the LEO satellite in the current epoch includes: determining the AoA information according to the opportunity signal and the direction vector of the opportunity signal; and extracting the Doppler shift information according to the opportunity signal using the maximum likelihood estimation method.

[0043] Specifically, the angle of arrival includes the azimuth angle and the elevation angle, which refers to the propagation direction of the received signal in space and can reflect the positional relationship between the signal source and the receiver. Thus, with the iThe azimuth identification of the angle of arrival of the signals corresponding to the low-earth orbit satellites is , and the elevation identification is .

[0044] The receiver uses a phased array antenna to receive the opportunity signals. Among them, the phased array antenna is a two-dimensional array, and the number of antenna elements can be, for example, or . Thus, the direction vector of the opportunity signals is:

[0045] ,

[0046] ,

[0047] .

[0048] Among them, represents the phase difference of the opportunity signals at the L th antenna element, is the signal wavelength of the opportunity signals corresponding to the i th low-earth orbit satellite, M is the number of antenna elements, L = 1 to M , is the unit vector in the propagation direction of the opportunity signals of the i th low-earth orbit satellite, is the position vector of the L th antenna element, e represents the base of the natural logarithm, j represents the imaginary number.

[0049] Furthermore, the computing device forms a directional beam by adjusting the excitation (phase and amplitude) of the antenna elements, scans the entire space to find the maximum response direction of the signals. Thus, the computing device can match the direction vector with the received signals:

[0050] .

[0051] Among them, w i is the beam weight corresponding to the i th low-earth orbit satellite. Thus, the computing device uses the direction vector as the beam weight w i , xa i is the opportunity signal received corresponding to the i th low-earth orbit satellite. When the beam is aligned with the signal direction of the opportunity signals, the output power reaches the maximum value. Furthermore, the computing device determines the azimuth of the angle of arrival information of the signals and the elevation angle 。

[0052] Furthermore, when the signal subcarrier can be regarded as a sinusoidal signal with stable frequency in a short period of time, the maximum likelihood estimation method can be used to extract the Doppler frequency shift information of the opportunistic signal. The opportunistic signal is represented by the following formula:

[0053] 。

[0054] where A i , , is the amplitude, angular frequency and phase of the sinusoidal signal corresponding to the opportunistic signal of the i th low-earth orbit satellite, n is used to identify the sampling point number, is zero-mean Gaussian white noise. The optimal estimation function is:

[0055] 。

[0056] where LN i is the processing data length of the opportunistic signal of the i th low-earth orbit satellite, and the estimated angular frequency i of the opportunistic signal of the th low-earth orbit satellite is:

[0057] 。

[0058] The corresponding Doppler frequency shift information i of the th low-earth orbit satellite is:

[0059] 。

[0060] Therefore, by using the phased array antenna to receive signals and combining with the direction vector for matching, this technical solution can accurately determine the maximum response direction of the signal, thereby accurately obtaining the signal arrival angle information (including the azimuth angle and the elevation angle), and enhancing the understanding of the positional relationship between the low-earth orbit satellite and the receiver.

[0061] Optionally, the operation of generating the rough positioning information of the receiver according to the signal arrival angle information and the orbit information includes: determining the unit vector of the signal propagation direction according to the signal arrival angle information; constructing the space straight line equation between the low-earth orbit satellite and the receiver according to the unit vector and the three-dimensional position coordinates in the orbit information; and calculating the rough positioning information of the receiver according to the space straight line equation.

[0062] Specifically, when the number of low-earth orbit (LEO) satellites is not less than a preset number of satellites (i.e., 4), the computing device determines the final positioning information of the receiver using a serial fusion method. The serial fusion method includes two steps: roughly positioning the receiver based on the angle of arrival (AoA) information of the signal, and then performing final positioning of the receiver based on the Doppler shift information.

[0063] More specifically, the steps for the computing device to roughly position the receiver include:

[0064] First, the computing device determines the unit vector of the signal propagation direction i i in terms of the azimuth angle and elevation angle d i of the AoA information corresponding to the

[0065] .

[0066] After that, the computing device determines the three-dimensional position coordinates of the orbital information of each LEO satellite . Among them, represents the three-dimensional position coordinates of the i th LEO satellite. Then, based on the unit vector d i and the corresponding three-dimensional position coordinates , the computing device constructs the space straight-line equation i i L i between the

[0067] th LEO satellite and the receiver:

[0068] Among them, t represents a parameter.

[0069] For example, to construct the space straight-line equation between the 1st LEO satellite and the receiver L 1 :

[0070] ;

[0071] To construct the space straight-line equation between the 2nd LEO satellite and the receiver L 2 :

[0072] ;

[0073] And so on, to construct the space straight-line equation between the N th LEO satellite and the receiver L N :

[0074] 。

[0075] Furthermore, the computing device will N the spatial straight-line equations of L 1 ~ L N simultaneously solve the equations. Then, the computing device calculates the distances between each spatial straight line and the receiver according to the equations, so as to determine the intersection point that minimizes the sum of the distances between each spatial straight line and the receiver, and uses it as the rough positioning information of the receiver 。

[0076] Therefore, this technical solution first generates an initial value through angle-of-arrival positioning and then uses Doppler frequency shift positioning, which reduces the number of iterative calculations and improves the calculation speed.

[0077] Optionally, the operation of calculating the rough positioning information of the receiver according to the spatial straight-line equations includes: calculating the rough positioning information of the receiver according to the following objective function:

[0078] ,

[0079] where ( x , y , z ) represents the three-dimensional position coordinates of the receiver, L i represents the spatial straight line determined by the i th low-earth orbit satellite and the receiver, N represents the number of low-earth orbit satellites, Distance () represents the distance calculation function.

[0080] Specifically, the computing device calculates the mean value of the projection points of all low-earth orbit satellites on the earth's surface according to the three-dimensional position coordinates of the low-earth orbit satellites. Then, the computing device uses this mean value as the initial value of ([[]] in the optimization formula for calculating the rough positioning information of the receiver x , y , z ).

[0081] Furthermore, the computing device determines the initial value of L i in the optimization formula according to the equations composed of the spatial straight-line equations. Then, the computing device uses the least squares method to calculate and solve the equations N formed by the spatial straight-line equations of L 1 ~ L N and uses the optimization formula As a solution target, the rough positioning information of the receiver is calculated accordingly. . When iteratively calculating the rough positioning information of the receiver, if the result calculated according to the optimization formula at the k +1-th time is worse than that at the k -th time, then roll back, and use the result at the k -th time ([[]] x , y , z ) as the rough positioning information . Otherwise, update the positioning result and change the L i value for the next iteration, and repeat the above steps until the iteration result converges (that is, there is no obvious change in the iterative calculation results for multiple consecutive times). Among them, the receiver coordinates ([[]] k ) calculated at the x , y , z ) obtained from the k +1-th iteration can be used to inversely solve the parameters L i corresponding to each in the L i value, so as to change the

[0082] . Thus, this technical solution combines the objective function with the space straight-line equation of the low-earth orbit satellite to calculate the position coordinates of the receiver in three-dimensional space, effectively reducing the positioning error.

[0083] Optionally, the operation of using the rough positioning information as the initial value for iterative solution in the Doppler positioning process to determine the final positioning information of the receiver includes: constructing a Doppler frequency shift observation equation according to the Doppler frequency shift information and the orbit information; constructing an iterative formula according to the Doppler frequency shift observation equation and the rough positioning information as the initial value; and performing iterative solution on the iterative formula to determine the final positioning information of the receiver.

[0084] Specifically, the computing device obtains the Doppler frequency shift information and the orbit information, and then constructs a Doppler frequency shift observation equation according to the Doppler frequency shift information and the orbit information:

[0085] .

[0086] Among them is the satellite transmission signal frequency, is the receiver clock offset, is the frequency reception error, v i represents the three-dimensional velocity of the i -th low-earth orbit satellite, represents the receiver three-dimensional position coordinates, represents thei The three-dimensional position coordinates of a low-earth orbit satellite c denotes the wave velocity f (i) ( u ) represents the Doppler frequency shift information of the i th low-earth orbit satellite .

[0087] Furthermore, the computing device constructs an iterative formula:

[0088] ,

[0089] .

[0090] Wherein, k is the number of iterations u k is the estimated value of the k th iterative solution u , is the residual vector is the partial derivative of the Doppler frequency shift observation equation of the i th low-earth orbit satellite at u k .

[0091] Furthermore, the computing device uses the rough positioning information of the receiver as the initial values of , , in the iterative formula, and the initial value of is 0. Thereafter, the computing device performs iterative solution on the iterative formula, and uses the obtained from the kth iterative solution as the , , , of the (k + 1)th time, so as to calculate x , y , z , for each round. Thereafter, in the case of convergence, the x , y , z calculated are used as the final positioning information .

[0092] Therefore, this technical solution constructs an accurate Doppler frequency shift observation equation by using Doppler frequency shift information and orbit information, and performs iterative solution in combination with rough positioning information, which can effectively reduce the positioning error and improve the reliability of the positioning result.

[0093] ​Optionally, the operation of constructing a Doppler shift observation equation based on Doppler shift information and orbital information includes: taking the Doppler shift information as the initial value f (i) ( u ), and constructing a Doppler shift observation equation according to the following formula:

[0094] ,

[0095] where is the satellite transmission signal frequency, is the receiver clock offset, is the frequency reception error, v i represents the three-dimensional velocity of the i th low-earth orbit satellite, represents the receiver three-dimensional position coordinates, represents the i th low-earth orbit satellite's three-dimensional position coordinates, c represents the wave speed.

[0096] Thus, by comprehensively considering various factors such as the satellite transmission signal frequency, receiver clock offset, and frequency reception error, this technical solution effectively reduces the influence of external interference on the positioning result and improves the robustness of the system.

[0097] Optionally, the operation of calculating the final positioning information of the receiver based on the signal arrival angle information, Doppler shift information, and orbital information includes: determining the unit vector of the signal propagation direction according to the signal arrival angle information; constructing a space straight line equation between the low-earth orbit satellite and the receiver based on the unit vector and the three-dimensional position coordinates in the orbital information; constructing a Doppler shift equation according to the Doppler shift information and orbital information; using a preset second optimization formula, with the goal of minimizing the signal arrival angle residual and Doppler shift residual, calculating the final positioning information of the receiver according to the space straight line equation and the Doppler shift equation.

[0098] Specifically, when the number of low-earth orbit satellites is less than the preset number of satellites (i.e., 4), the computing device determines the final positioning information of the receiver using a parallel fusion method.

[0099] More specifically, the computing device determines the unit vector i of the signal propagation direction according to the azimuth angle and elevation angle corresponding to the signal arrival angle information of the d i th low-earth orbit satellite:

[0100] .

[0101] After that, the computing device determines the three-dimensional position coordinates of the orbit information of each low-earth orbit satellite . Among them represents the three-dimensional position coordinates of the i th low-earth orbit satellite. After that, the computing device constructs the space straight-line equation between the d i th low-earth orbit satellite and the receiver according to the unit vector and the corresponding three-dimensional position coordinates i : L i :

[0102] .

[0103] Furthermore, the computing device obtains the Doppler frequency shift information and the orbit information, and then constructs the Doppler frequency shift observation equation according to the Doppler frequency shift information and the orbit information:

[0104] ,

[0105] where is the satellite transmission signal frequency, is the receiver clock offset, is the frequency reception error, v i represents the three-dimensional velocity of the i th low-earth orbit satellite, represents the receiver three-dimensional position coordinates, represents the i th low-earth orbit satellite three-dimensional position coordinates, c represents the wave velocity, f (i) ( u ) represents the Doppler frequency shift information of the i th low-earth orbit satellite, represents the unknowns to be solved, including: the receiver three-dimensional position coordinates and the receiver clock offset .

[0106] Furthermore, the computing device constructs the Doppler frequency shift equation:

[0107] ,

[0108] .

[0109] Among them, k is the number of iterations, u k is the estimated value of the k th iteration solution u , is the residual vector, is the i partial derivative of the Doppler frequency shift observation equation of the u k th low-earth orbit satellite at x 0 . Among them, y 0 , z 0 The initial value at the first iteration is N the mean of the projection points of the th low-earth orbit satellites on the earth's surface, and f (i) ( u ) represents the Doppler frequency shift information of the i th low-earth orbit satellite, .

[0110] Furthermore, the computing device forms a system of equations from the straight-line equation L i and the Doppler frequency shift equation. For example, when the number of low-earth orbit satellites is 3, the system of equations is:

[0111] ,

[0112] ,

[0113] ,

[0114] .

[0115] Furthermore, the computing device calculates ( x , y , z ) and according to the system of equations formed by the space straight-line equation and the Doppler frequency shift equation, and inputs ( x , y , z ) and into the objective function. Among them, ( x , y , z ) is the intersection point between the space straight-line equation L 1 ~ L 3 . Thus, the computing device uses the obtained by the k-th iteration solution as the x 0 of the (k + 1)-th time, y 0 , z 0 , , using a preset objective function, with the goal of minimizing the signal arrival angle residual and Doppler frequency shift residual, iteratively calculate the final positioning information of the receiver S ( x , y , z ), where the objective function is:

[0116] ,

[0117] ,

[0118] .

[0119] Wherein is the signal arrival angle residual of the i th low-earth orbit satellite, is the Doppler frequency shift residual of the i th low-earth orbit satellite, represents the Doppler frequency shift information of the i th low-earth orbit satellite.

[0120] Therefore, this technical solution determines the final positioning information of the receiver through a parallel fusion method, enabling the use of the straight-line equation and Doppler frequency shift equation to meet the positioning requirements when the number of low-earth orbit satellites is small.

[0121] In addition, according to research, multiple observables can be obtained by adding sensors for multi-source fusion positioning, thereby improving the positioning accuracy and reducing the number of satellites required for single-epoch positioning. Among them, multi-source fusion positioning can be, for example, by adding sensors such as altimeters and gyroscopes to obtain the altitude information of the receiver or the position and velocity information from the inertial navigation system, and fusing this information with the observable information obtained from the satellite navigation system through a Kalman filter.

[0122] In addition, as shown in Figure 1 , according to the second aspect of this embodiment, a storage medium is provided. The storage medium includes a stored program, wherein, when the program runs, the method described in any one of the above is executed by a processor.

[0123] Therefore, according to this embodiment, the computing device sets two different positioning methods according to the number of low-earth orbit satellites, including a serial fusion method and a parallel fusion method, so that the number of low-earth orbit satellites can be flexibly applied, improving the flexibility and applicability of the system. And when the number of low-earth orbit satellites is small, the equations for positioning based on the angle-of-arrival information of the signal and the equations for positioning based on the Doppler frequency shift information are used to calculate the final positioning information of the receiver simultaneously, increasing the number of observables, thereby reducing the dependence on the initial value of the target position, reducing the number of iterative solutions, and accelerating the positioning speed. And when the number of low-earth orbit satellites is large in this technical solution, the rough positioning information of the receiver is first calculated according to the angle-of-arrival information of the signal as the initial value for the Doppler positioning solution process for calculating the final positioning information of the receiver, thereby limiting the initial value within a reasonable range, reducing the number of iterative solutions, and improving the calculation speed. Furthermore, it solves the technical problems in the prior art that the positioning result of Doppler frequency shift positioning is limited by the number of low-earth orbit satellites, the instantaneous positioning is limited by the number of observed satellites, and the lack of the initial value in the Doppler positioning solution process leads to an increase in the number of iterative solutions.

[0124] It should be noted that, for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0125] Through the description of the above embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be implemented by means of software plus a necessary general hardware platform. Of course, it can also be implemented by hardware, but in many cases the former is a better implementation. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions for causing a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in various embodiments of the present invention.

[0126] Embodiment 2

[0127] Figure 3 Fig. shows a positioning device 300 based on the opportunity signal of low-earth orbit satellites according to this embodiment. The device 300 corresponds to the method described in the first aspect of Embodiment 1. Refer to Figure 3As shown in the figure, the device 300 includes: an information extraction module 310, configured to extract corresponding signal arrival angle information and Doppler frequency shift information according to the opportunity signals of low-earth orbit satellites in the current epoch, where the signal arrival angle information is used to indicate the positional relationship between the low-earth orbit satellite and the receiver, and the Doppler frequency shift information is used to indicate the relative motion information between the low-earth orbit satellite and the receiver; an information determination module 320, configured to determine the orbit information of the low-earth orbit satellite in the current epoch according to a preset two-line element set (TLE) file of the satellite and a satellite orbit prediction model; a first positioning information determination module 330, configured to generate rough positioning information of the receiver according to the signal arrival angle information and the orbit information when the number of low-earth orbit satellites is not less than a preset number of satellites, and use the rough positioning information as the initial value of iterative calculation in the Doppler positioning process for iterative calculation to determine the final positioning information of the receiver; and a second positioning information determination module 340, configured to calculate the final positioning information of the receiver according to the signal arrival angle information, the Doppler frequency shift information, and the orbit information when the number of low-earth orbit satellites is less than the preset number of satellites.

[0128] Optionally, the information extraction module 310 includes: a first determination sub-module, configured to determine the signal arrival angle information according to the opportunity signal and the direction vector of the opportunity signal; and an information extraction sub-module, configured to extract the Doppler frequency shift information according to the opportunity signal by using the maximum likelihood estimation method.

[0129] Optionally, the first positioning information determination module 330 includes: a second determination sub-module, configured to determine the unit vector of the signal propagation direction according to the signal arrival angle information; a first construction sub-module, configured to construct a space straight line equation between the low-earth orbit satellite and the receiver according to the unit vector and the three-dimensional position coordinates in the orbit information; and a first calculation sub-module, configured to calculate the rough positioning information of the receiver according to the space straight line equation.

[0130] Optionally, the first calculation sub-module includes: a first calculation unit, configured to calculate the rough positioning information of the receiver according to the following objective function:

[0131] ,

[0132] where ([ x , y , z ) represents the three-dimensional position coordinates of the receiver, L i represents the space straight line determined by the i-th low-earth orbit satellite and the receiver, N represents the number of low-earth orbit satellites, Distance () represents the distance calculation function.

[0133] Optionally, the first positioning information determination module 330 includes: a second construction sub-module for constructing a Doppler frequency shift observation equation according to the Doppler frequency shift information and the orbit information; a third construction sub-module for constructing an iterative formula according to the Doppler frequency shift observation equation and the rough positioning information as the initial value; and a third determination sub-module for performing iterative solution on the iterative formula to determine the final positioning information of the receiver.

[0134] Optionally, the second construction sub-module includes: a construction unit for using the Doppler frequency shift information as the initial value f ( u ) and constructing a Doppler frequency shift observation equation according to the following formula:

[0135] ,

[0136] where is the satellite transmission signal frequency, is the receiver clock offset, is the frequency reception error, v i represents the three-dimensional velocity of the i th low-earth orbit satellite, represents the receiver three-dimensional position coordinates, represents the i th low-earth orbit satellite three-dimensional position coordinates, c represents the wave velocity.

[0137] Optionally, the second positioning information determination module 340 includes: a fourth determination sub-module for determining the unit vector of the signal propagation direction according to the signal arrival angle information; a fourth construction sub-module for constructing a space straight line equation between the low-earth orbit satellite and the receiver according to the unit vector and the three-dimensional position coordinates in the orbit information; a fifth construction sub-module for constructing a Doppler frequency shift equation according to the Doppler frequency shift information and the orbit information; a fifth determination sub-module for taking the minimum of the signal arrival angle residual and the Doppler frequency shift residual as the target, and calculating the final positioning information of the receiver according to the space straight line equation and the Doppler frequency shift equation.

[0138] Therefore, according to this embodiment, the computing device sets two different positioning methods according to the number of low-earth orbit satellites, including a serial fusion method and a parallel fusion method, so that the number of low-earth orbit satellites can be flexibly applied, improving the flexibility and applicability of the system. And when the number of low-earth orbit satellites is small, the equations for positioning based on the angle-of-arrival information of the signal and the equations for positioning based on the Doppler frequency shift information are used to calculate the final positioning information of the receiver simultaneously, increasing the number of observables, thereby reducing the dependence on the initial value of the target position, reducing the number of iterative solutions, and accelerating the positioning speed. And when the number of low-earth orbit satellites is large in this technical solution, the rough positioning information of the receiver is first calculated based on the angle-of-arrival information of the signal and used as the initial value for the Doppler positioning solution process for calculating the final positioning information of the receiver, thereby limiting the initial value within a reasonable range, reducing the number of iterative solutions, and improving the calculation speed. Furthermore, the technical problems existing in the prior art that the positioning result of Doppler frequency shift positioning is limited by the number of low-earth orbit satellites, the instantaneous positioning is limited by the number of observed satellites, and the lack of the initial value in the Doppler positioning solution process leads to an increase in the number of iterative solutions are solved.

[0139] Embodiment 3

[0140] Figure 4 Fig. shows the positioning device 400 based on the opportunity signal of low-earth orbit satellites according to this embodiment, and this device 400 corresponds to the method described in the first aspect of Embodiment 1. Refer to Figure 4 As shown, the device 400 includes: a processor 410; and a memory 420, connected to the processor 410, for providing instructions for the processor 410 to perform the following processing steps: extracting the corresponding angle-of-arrival information and Doppler frequency shift information of the signal according to the opportunity signal of the low-earth orbit satellites in the current epoch, where the angle-of-arrival information is used to indicate the positional relationship between the low-earth orbit satellite and the receiver, and the Doppler frequency shift information is used to indicate the relative motion information between the low-earth orbit satellite and the receiver; determining the orbit information of the low-earth orbit satellites in the current epoch according to the preset two-line element set file of the satellites and the satellite orbit prediction model; when the number of low-earth orbit satellites is not less than the preset number of satellites, generating the rough positioning information of the receiver according to the angle-of-arrival information and the orbit information, and using the rough positioning information as the initial value for iterative solution in the Doppler positioning process to determine the final positioning information of the receiver; and when the number of low-earth orbit satellites is less than the preset number of satellites, calculating the final positioning information of the receiver according to the angle-of-arrival information, the Doppler frequency shift information, and the orbit information.

[0141] Optionally, the operation of extracting the corresponding signal arrival angle information and Doppler frequency shift information according to the opportunity signal of the LEO satellite in the current epoch includes: determining the signal arrival angle information according to the opportunity signal and the direction vector of the opportunity signal; and extracting the Doppler frequency shift information according to the opportunity signal by using the maximum likelihood estimation method.

[0142] Optionally, the operation of generating the rough positioning information of the receiver according to the signal arrival angle information and the orbit information includes: determining the unit vector of the signal propagation direction according to the signal arrival angle information; constructing the space straight line equation between the LEO satellite and the receiver according to the unit vector and the three-dimensional position coordinates in the orbit information; and calculating the rough positioning information of the receiver according to the space straight line equation.

[0143] Optionally, the operation of calculating the rough positioning information of the receiver according to the space straight line equation includes: calculating the rough positioning information of the receiver according to the following objective function:

[0144] ,

[0145] where ( x , y , z ) represents the three-dimensional position coordinates of the receiver, L i represents the space straight line determined by the i-th LEO satellite and the receiver, N represents the number of LEO satellites, Distance () represents the distance calculation function.

[0146] Optionally, the operation of using the rough positioning information as the initial value of the iterative solution in the Doppler positioning process to determine the final positioning information of the receiver includes: constructing the Doppler frequency shift observation equation according to the Doppler frequency shift information and the orbit information; constructing the iterative formula according to the Doppler frequency shift observation equation and the rough positioning information as the initial value; and performing iterative solution on the iterative formula to determine the final positioning information of the receiver.

[0147] Optionally, the operation of constructing the Doppler frequency shift observation equation according to the Doppler frequency shift information and the orbit information includes: taking the Doppler frequency shift information as the initial value f ( u ), and constructing the Doppler frequency shift observation equation according to the following formula:

[0148] ,

[0149] where is the satellite transmission signal frequency, is the receiver clock offset, is the frequency reception error, v i represents thei The three-dimensional velocity of a low-earth orbit satellite, denotes the three-dimensional position coordinates of the receiver, denotes the i three-dimensional position coordinates of the c nth low-earth orbit satellite,

[0150] Optionally, the operation of calculating the final positioning information of the receiver according to the signal arrival angle information, Doppler shift information, and orbit information includes: determining the unit vector of the signal propagation direction according to the signal arrival angle information; constructing the space straight line equation between the low-earth orbit satellite and the receiver according to the unit vector and the three-dimensional position coordinates in the orbit information; constructing the Doppler shift equation according to the Doppler shift information and the orbit information; and calculating the final positioning information of the receiver according to the space straight line equation and the Doppler shift equation with the goal of minimizing the signal arrival angle residual and the Doppler shift residual.

[0151] Therefore, according to this embodiment, the computing device sets two different positioning methods according to the number of low-earth orbit satellites, including the serial fusion method and the parallel fusion method, so as to flexibly apply the number of low-earth orbit satellites, improving the flexibility and applicability of the system. And when the number of low-earth orbit satellites is small, the equations for positioning according to the signal arrival angle information and the equations for positioning according to the Doppler shift information are used to calculate the final positioning information of the receiver simultaneously, increasing the number of observables, thereby reducing the dependence on the initial value of the target position, reducing the number of iterative solutions, and accelerating the positioning speed. And when the number of low-earth orbit satellites is large in this technical solution, the rough positioning information of the receiver is first calculated according to the signal arrival angle information as the initial value for the Doppler positioning solution process for calculating the final positioning information of the receiver, thereby limiting the initial value within a reasonable range, reducing the number of iterative solutions, and improving the calculation speed. Furthermore, the technical problems existing in the prior art, such as the positioning result of Doppler shift positioning being limited by the number of low-earth orbit satellites, the instantaneous positioning being limited by the number of observed satellites, and the lack of the initial value in the Doppler positioning solution process leading to an increase in the number of iterative solutions, are solved.

[0152] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0153] In the above embodiments of the present invention, the descriptions of each embodiment have their own focuses. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0154] In several embodiments provided by this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the couplings or direct couplings or communication connections shown or discussed with each other can be through some interfaces. The indirect couplings or communication connections of units or modules can be in electrical or other forms.

[0155] The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0156] In addition, in each embodiment of the present invention, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0157] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present invention. The foregoing storage medium includes: various media such as USB flash drives, read-only memories (ROMs), random access memories (RAMs), mobile hard disks, magnetic disks or optical discs that can store program codes.

[0158] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A positioning method based on low-orbit satellite opportunity signals, characterized in that: include: Extracting corresponding signal arrival angle information and Doppler frequency shift information according to the opportunity signal of the low-orbit satellite in the current epoch, wherein the signal arrival angle information is used to indicate the positional relationship between the low-orbit satellite and the receiver, and the Doppler frequency shift information is used to indicate the relative motion information between the low-orbit satellite and the receiver; Determine the orbit information of the low-orbit satellite at the current epoch according to a preset two-line satellite orbit data file and a satellite orbit prediction model; In a case where the number of the low-orbit satellites is not less than a preset number of satellites, coarse positioning information of the receiver is generated according to the signal arrival angle information and the orbit information, and the coarse positioning information is used as an initial value of iterative solution in a Doppler positioning process for iterative solution to determine final positioning information of the receiver; as well as When the number of the low-orbit satellites is less than the preset number of satellites, the final positioning information of the receiver is calculated according to the signal arrival angle information, the Doppler frequency shift information and the orbit information, and wherein: The operation of generating the coarse positioning information of the receiver according to the signal arrival angle information and the orbital information includes: determining the unit vector of the signal propagation direction according to the signal arrival angle information; constructing the spatial straight line equation between the low-orbit satellite and the receiver according to the unit vector and the three-dimensional position coordinates in the orbital information; and calculating the coarse positioning information of the receiver according to the spatial straight line equation.

2. The method according to claim 1, characterized in that According to the opportunity signal of the low-orbit satellite in the current epoch, the operation of extracting the corresponding signal arrival angle information and Doppler frequency shift information includes: Determining the signal arrival angle information according to the opportunity signal and the direction vector of the opportunity signal; and The Doppler frequency shift information is extracted according to the opportunity signal using a maximum likelihood estimation method.

3. The method according to claim 1, characterized in that The operation of calculating the coarse positioning information of the receiver according to the spatial straight line equation includes: The coarse positioning information of the receiver is calculated according to the following objective function: ， in( x , y , z ) represents the three-dimensional position coordinates of the receiver, L i Indicated by i A space straight line determined by a low-orbit satellite and the receiver, N represents the number of the low-orbit satellites, Distance () represents the distance calculation function.

4. The method according to claim 1, characterized in that The operation of iteratively solving the coarse positioning information as the initial value of iterative solving in the Doppler positioning process to determine the final positioning information of the receiver includes: Constructing a Doppler frequency shift observation equation according to the Doppler frequency shift information and the orbit information; Constructing an iterative formula according to the Doppler frequency shift observation equation and the coarse positioning information as an initial value; and The iterative formula is iteratively solved to determine final positioning information of the receiver.

5. The method according to claim 4, characterized in that The operation of constructing a Doppler frequency shift observation equation according to the Doppler frequency shift information and the orbit information includes: The Doppler frequency shift information is used as the initial value , and construct the Doppler frequency shift observation equation according to the following formula: ， in is the frequency of satellite signal transmission, is the receiver clock bias, is the frequency receiving error, v i Indicates i The three-dimensional velocity of the low-orbit satellite, x Indicates the three-dimensional position information of the receiver, x s i Indicates i The three-dimensional position information of low-orbit satellites, c Indicates wave speed.

6. The method according to claim 1, characterized in that The operation of calculating the final positioning information of the receiver according to the signal arrival angle information, the Doppler frequency shift information and the orbit information includes: Determine a unit vector of a signal propagation direction according to the signal arrival angle information; Constructing a spatial straight line equation between the low-orbit satellite and the receiver according to the unit vector and the three-dimensional position coordinates in the orbit information; Constructing a Doppler frequency shift equation according to the Doppler frequency shift information and the orbit information; With the goal of minimizing the signal arrival angle residual and the Doppler frequency shift residual, the final positioning information of the receiver is calculated according to the spatial straight line equation and the Doppler frequency shift equation.

7. A positioning device based on low-orbit satellite opportunity signals, characterized in that: include: An information extraction module, configured to extract corresponding signal arrival angle information and Doppler frequency shift information according to the opportunity signal of the low-orbit satellite in the current epoch, wherein the signal arrival angle information is used to indicate the positional relationship between the low-orbit satellite and the receiver, and the Doppler frequency shift information is used to indicate the relative motion information between the low-orbit satellite and the receiver; An information determination module, used to determine the orbit information of the low-orbit satellite at the current epoch according to a preset satellite two-line orbit data file and a satellite orbit prediction model; a first positioning information determination module, configured to generate coarse positioning information of the receiver according to the signal arrival angle information and the orbit information when the number of the low-orbit satellites is not less than a preset number of satellites, and to perform iterative solution using the coarse positioning information as an initial value of iterative solution in a Doppler positioning process to determine final positioning information of the receiver; as well as The second positioning information determination module is used to calculate the final positioning information of the receiver according to the signal arrival angle information, the Doppler frequency shift information and the orbit information when the number of the low-orbit satellites is less than the preset number of satellites, and wherein: The first positioning information determination module includes: a second determination submodule, which determines the unit vector of the signal propagation direction according to the signal arrival angle information; a first construction submodule, which constructs the spatial straight line equation between the low-orbit satellite and the receiver according to the unit vector and the three-dimensional position coordinates in the orbital information; and a first calculation submodule, which calculates the coarse positioning information of the receiver according to the spatial straight line equation.

8. A positioning device based on low-orbit satellite opportunity signals, characterized in that: include: processor; as well as A memory, connected to the processor, configured to provide the processor with instructions for processing the following processing steps: Extracting corresponding signal arrival angle information and Doppler frequency shift information according to the opportunity signal of the low-orbit satellite in the current epoch, wherein the signal arrival angle information is used to indicate the positional relationship between the low-orbit satellite and the receiver, and the Doppler frequency shift information is used to indicate the relative motion information between the low-orbit satellite and the receiver; Determine the orbit information of the low-orbit satellite at the current epoch according to a preset two-line satellite orbit data file and a satellite orbit prediction model; In a case where the number of the low-orbit satellites is not less than a preset number of satellites, coarse positioning information of the receiver is generated according to the signal arrival angle information and the orbit information, and the coarse positioning information is used as an initial value of iterative solution in a Doppler positioning process for iterative solution to determine final positioning information of the receiver; as well as When the number of the low-orbit satellites is less than the preset number of satellites, the final positioning information of the receiver is calculated according to the signal arrival angle information, the Doppler frequency shift information and the orbit information, and wherein: The operation of generating the coarse positioning information of the receiver according to the signal arrival angle information and the orbital information includes: determining the unit vector of the signal propagation direction according to the signal arrival angle information; constructing the spatial straight line equation between the low-orbit satellite and the receiver according to the unit vector and the three-dimensional position coordinates in the orbital information; and calculating the coarse positioning information of the receiver according to the spatial straight line equation.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to claim 1 are implemented.

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