Satellite-borne gnss multipath modeling method, device and equipment and storage medium

Abstract

The application belongs to the technical field of satellite signal processing, and provides a satellite-borne GNSS multipath modeling method, device, equipment and storage medium. The method comprises: establishing a satellite three-dimensional model and a signal source model in the same coordinate system to simulate the incidence process of the signal; when the signal ray emitted by the signal source model has an intersection with the satellite three-dimensional model, it is considered that there may be a reflected signal; the possible reflected signal is verified according to the intensity ratio of the signal ray before and after passing through the reflection surface of the satellite three-dimensional model; if the intensity ratio is within a set range, it is confirmed that the reflected signal exists; in the case that the reflected signal exists, the reflection point and the reflection path are calculated; the code pseudorange delay, the carrier phase delay and the Doppler delay are calculated to obtain a multipath error model. The method can calculate the multipath error of a satellite-borne receiver, and realize the suppression of the multipath effect at a low cost.

Description

Technical Field

[0001] This application relates to the field of satellite signal processing technology, and in particular to a method, apparatus, device and storage medium for satellite-borne GNSS multipath modeling. Background Technology

[0002] Global Navigation Satellite System (GNSS) is currently the most widely used positioning technology. It is characterized by its wide applicability and high accuracy, meeting users' positioning needs in different regions and finding broad applications in military, civilian, and many other fields. In recent years, with the development of satellite applications, people have placed higher demands on the accuracy of satellite positioning.

[0003] Determining satellite orbits is a prerequisite for achieving high-precision satellite positioning. If the satellite orbit is not accurately determined, the satellite's position in space will have a significant error. When a user receives signals from the satellite for positioning, the calculated user position will also be inaccurate due to the satellite's position deviation. Therefore, to achieve high-precision positioning, higher requirements have been placed on the accuracy of satellite orbit determination.

[0004] Addressing the multipath effect during signal propagation is crucial. The multipath effect refers to the phenomenon where, when a direct signal reaches the receiving antenna, reflected and refracted signals also arrive simultaneously, contaminating the direct signal. After receiving the signal, the receiving antenna uses a radio frequency front-end, digital signal processor, and navigation and positioning calculation module to calculate the position information. Because multipath signals travel over longer distances than direct signals, the transmission distance delay leads to pseudorange and carrier errors. If the onboard receiver directly calculates the position without processing these multipath signals, it will severely impact orbit determination accuracy.

[0005] However, current research on multipath suppression methods for spaceborne receivers has certain shortcomings. First, the multipath suppression rate is a crucial indicator for evaluating suppression methods: accurately acquiring the direct signal amidst multipath interference is a primary concern. Second, cost is a significant issue: methods to suppress multipath effects, such as improving antenna arrays, often involve higher costs and increased receiver size and weight. Furthermore, the applicability of multipath suppression methods needs attention: continuous optimization is necessary to ensure the multipath suppression model is suitable for various environments and spaceborne receivers. Continuously improving multipath suppression methods for spaceborne receivers, increasing the suppression rate while minimizing cost and broadening applicability, is beneficial for ensuring high-precision orbit determination calculations by spaceborne receivers. Summary of the Invention

[0006] This application provides a method, apparatus, device, and storage medium for satellite-borne GNSS multipath modeling, which can calculate the multipath error of a satellite-borne receiver and suppress multipath effects at a lower cost.

[0007] Firstly, this application provides a spaceborne GNSS multipath modeling method, including:

[0008] In the same coordinate system, a three-dimensional model of the satellite and a signal source model are established to simulate the incident process of the signal. When the signal ray emitted by the signal source model intersects with the three-dimensional model of the satellite, it is confirmed that there may be a reflected signal.

[0009] Based on the intensity ratio of the signal ray before and after the reflection of the satellite's three-dimensional model, the possible reflected signals are verified. If the intensity ratio is within the set range, the existence of the reflected signal is confirmed.

[0010] Calculate the reflection point and reflection path when the reflected signal is present;

[0011] The code pseudorange delay, carrier phase delay, and Doppler delay are calculated to obtain the multipath error model.

[0012] Furthermore, in the same coordinate system, a three-dimensional model of the satellite and a signal source model are established to simulate the signal incident process. When the signal ray emitted by the signal source model intersects with the three-dimensional model of the satellite, it is confirmed that a reflected signal may exist, including:

[0013] Establish a reference coordinate system with the satellite's center of mass as the origin. Determine the direction of the coordinate axes based on the satellite's attitude. Treat the platform on which the satellite is located as a rigid body. Use three-dimensional coordinates to represent the position of the receiving antenna of the onboard receiver. Determine the reflecting surface that may generate multipath signals and determine the equation of the reflecting surface.

[0014] Using GPS satellites as the signal source, the position of the signal source is represented by rectangular coordinates in the reference coordinate system. The receiving antenna is mirrored about the reflecting surface. The mirror image is connected to the signal source. If the line connecting the mirror image and the signal source intersects the reflecting surface, then a reflection path is determined to exist.

[0015] In the presence of a reflection path, the ray equation is determined based on the positions of the signal source and the receiving antenna. When the ray equation has a solution to the reflection surface equation, it indicates that the signal ray intersects the reflection surface, confirming the possible existence of a reflected signal.

[0016] Furthermore, based on the intensity ratio before and after the signal ray passes through the reflection surface of the satellite's three-dimensional model, the possible reflected signals are verified. If the intensity ratio is within a set range, the presence of the reflected signal is confirmed.

[0017] The reflection coefficient is calculated based on the measured signal intensity of the reflected ray.

[0018] If the reflection coefficient is between the reflection coefficients of vertical polarization and parallel polarization, then the presence of the reflected signal is confirmed; wherein, vertical polarization means that the electric field vector is perpendicular to the incident surface, and parallel polarization means that the electric field vector is parallel to the incident surface;

[0019] If the difference between the reflection coefficient and the refraction coefficient is within a set threshold range, then it is confirmed that the reflected signal does not exist.

[0020] Furthermore, the reflection coefficients for vertical and parallel polarization are calculated using the following method:

[0021] When a signal ray is incident from the first medium onto the second medium, the electric field strength of the incident wave, the electric field strength of the reflected wave, and the electric field strength of the refracted wave are calculated using the following formulas:

[0022] ;

[0023] ;

[0024] ;

[0025] In the formula, This represents the electric field strength of the incident wave. This represents the electric field strength of the reflected wave. This represents the electric field intensity of the refracted wave. Represents angular frequency. Represents the wave vector. λ represents wavelength. Represents the unit direction vector. Represents a spatial position vector. The scalar representing the electric field intensity of the incident wave. The electric field intensity scalar represents the reflected wave. The scalar quantity representing the electric field intensity of a refracted wave;

[0026] Based on the boundary conditions of Maxwell's equations, the reflection coefficient and refraction coefficient of vertical polarization can be obtained using the following formulas:

[0027] ;

[0028] ;

[0029] In the formula, Represents the reflection coefficient of vertical polarization. The refractive index represents the vertical polarization. This represents the dielectric constant of the first medium. Indicates the permeability of the first medium. This represents the dielectric constant of the second medium. Indicates the permeability of the second medium. Indicates the angle of refraction. Indicates the angle of incidence;

[0030] Based on the boundary conditions of Maxwell's equations, the reflection coefficient and refraction coefficient of parallel polarization can be obtained using the following formula:

[0031] ;

[0032] ;

[0033] In the formula, The reflection coefficient represents parallel polarization. This represents the refractive index for parallel polarization. When the intensity ratio of a signal before and after a reflection point falls between the parallel polarization reflection index and the vertical polarization reflection index at the interface, the signal is confirmed to be a multipath signal exhibiting reflection.

[0034] Furthermore, in the presence of the reflected signal, the reflection point and reflection path are calculated, including:

[0035] Taking the intersection of the line connecting the mirror image and the signal source with the reflecting surface as the reflection point, and arbitrarily selecting a point on the reflecting surface... The reflection point is obtained using the following formula:

[0036] ;

[0037] In the formula, Indicates the reflection point. Indicates the signal source. This represents the image of the receiving antenna with respect to the reflector. This indicates that the normal to the reflecting surface is in the opposite direction;

[0038] According to the law of reflection, the angle of reflection equals the angle of incidence, and the reflection path can be obtained from this.

[0039] Furthermore, the code pseudorange delay, carrier phase delay, and Doppler delay are calculated to obtain the multipath error model, including:

[0040] The geometric propagation distance between LOS and NLOS signals is determined by the following formula:

[0041] ;

[0042] ;

[0043] In the formula, This represents the geometric propagation distance of the LOS signal. This represents the vector between the signal source S and the receiving antenna A. , and These represent the receiving antennas. x Axis coordinates y Axis coordinates and z Axis coordinates , and These represent the locations of the signal sources. x Axis coordinates y Axis coordinates and z Axis coordinates Indicates the geometric propagation distance of the NLOS signal. This represents the vector between the signal source S and the reflection point Q. This represents the vector between the reflection point Q and the receiving antenna A. , and Representing the reflection points x Axis coordinates y Axis coordinates and z Axis coordinates;

[0044] For frequency The code delay of a GPS signal is determined by distance. Without considering the influence of differential code deviation, the code delay can be calculated using the following formula:

[0045] ;

[0046] ;

[0047] In the formula, Indicates the spreading code rate. Represents the speed of light. Indicates the code delay of the LOS signal. Indicates the code delay of the NLOS signal;

[0048] The carrier phase delay of the signal is calculated using the following formula:

[0049] ;

[0050] ;

[0051] In the formula, This indicates the carrier phase delay of the LOS signal. This indicates the carrier phase delay of the NLOS signal;

[0052] The carrier wavelength is defined as:

[0053] ;

[0054] In the formula, It is the carrier frequency, defined as:

[0055] ;

[0056] In the formula, For the fundamental frequency, Carrier factor;

[0057] The Doppler frequency shift is related to the relative orientation of the receiving antenna and the signal source. The formula for calculating the Doppler frequency of a LOS signal is:

[0058] ;

[0059] In the formula, The Doppler frequency represents the line-of-sight signal. and These are the velocity vectors of the signal source and the receiving antenna, respectively. , and These represent the components of the signal source velocity vector along the x, y, and z axes, respectively. , and These represent the components of the receiving antenna velocity vector along the x, y, and z axes, respectively.

[0060] The formula for calculating the Doppler frequency of an NLOS signal is:

[0061] ;

[0062] In the formula, Indicates the Doppler frequency of the NLOS signal;

[0063] The distance delay is calculated using the following formula. :

[0064] ;

[0065] The relative code pseudorange delay is calculated using the following formula. :

[0066] ;

[0067] The relative carrier phase delay is calculated using the following formula. :

[0068] ;

[0069] The relative Doppler delay is calculated using the following formula. :

[0070] .

[0071] Secondly, this application provides a spaceborne GNSS multipath modeling device, the device comprising:

[0072] The model building module is configured to build a satellite 3D model and a signal source model in the same coordinate system to simulate the signal incident process. When the signal ray emitted by the signal source model intersects with the satellite 3D model, it is confirmed that there may be a reflected signal.

[0073] The signal verification module is configured to verify possible reflected signals based on the intensity ratio before and after the signal ray passes through the reflection surface of the satellite's three-dimensional model. If the intensity ratio is within a set range, the existence of the reflected signal is confirmed.

[0074] The reflection calculation module is configured to calculate the reflection point and reflection path in the presence of the reflected signal;

[0075] The multipath modeling module is configured to calculate code pseudorange delay, carrier phase delay, and Doppler delay to obtain a multipath error model.

[0076] Thirdly, this application provides an electronic device, which includes: a processor and a memory; the memory is used to store instructions; the processor is used to execute the instructions in the memory, causing the electronic device to perform the method as described in the first aspect.

[0077] Fourthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the method described in the first aspect.

[0078] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the method described in the first aspect.

[0079] The spaceborne GNSS multipath modeling method, apparatus, equipment, and storage medium provided in this application have the following beneficial effects:

[0080] 1. Most existing results focus on ground receivers. This application is based on ray tracing to simulate the reflection problem of GPS signals on spaceborne receivers.

[0081] 2. This application does not rely on the redesign of receiver parts such as antennas or internal structures, has low cost, and has strong practical value.

[0082] 3. This application visually demonstrates the signal reflection process, unlike existing works that mostly distinguish multipath signals through a certain feature. This invention is more intuitive and accurate. Attached Figure Description

[0083] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0084] Figure 1 A flowchart illustrating a spaceborne GNSS multipath modeling method as an exemplary embodiment;

[0085] Figure 2 A schematic diagram of a satellite coordinate system shown as an exemplary embodiment;

[0086] Figure 3 A schematic diagram of the ENVISAT satellite reflector as an exemplary embodiment;

[0087] Figure 4 A schematic diagram illustrating LOS and NLOS signal models as an exemplary embodiment;

[0088] Figure 5 A flowchart illustrating the establishment of a multipath error model is provided for an exemplary embodiment.

[0089] Figure 6 This is a structural diagram of a spaceborne GNSS multipath modeling device, as shown in an exemplary embodiment.

[0090] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0091] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0092] It should be noted that the links involved in this application, as well as the related information in the links and platform-related information (including but not limited to data used for analysis, stored data, and displayed data), are all information and data that have been understood and authorized by the relevant users or have been fully authorized by all parties. Furthermore, the collection, use, processing, transmission, provision, disclosure, and application of the relevant data have all complied with the laws, regulations, and standards of the relevant countries and regions, taken necessary confidentiality measures, and have not violated public order and good morals, and have conformed to the principles of legality, legitimacy, and necessity.

[0093] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0094] This application provides a spaceborne GNSS multipath modeling method. It should be noted that the spaceborne GNSS multipath modeling method provided in this application can be implemented on any electronic device with data processing capabilities, or it can be a spaceborne GNSS multipath modeling system. Furthermore, the spaceborne GNSS multipath modeling system can be deployed independently on an electronic device in any environment (e.g., deployed independently on an edge server in an edge environment), or it can be deployed entirely in a cloud environment, or it can be distributed and deployed in different environments.

[0095] For example, a spaceborne GNSS multipath modeling system can be logically divided into multiple parts, each with different functions. These parts can be deployed in any two or three of the following environments: electronic devices (located on the user side, such as clients), edge environments, and cloud environments. An edge environment comprises a set of edge electronic devices located close to the electronic devices, including edge servers and edge stations with computing power. The various parts of the spaceborne GNSS multipath modeling system deployed in different environments or devices work together to realize the functions of a data processing platform.

[0096] It should be understood that this application does not restrict the specific deployment environment of which parts of the spaceborne GNSS multipath modeling system are deployed. In actual applications, the deployment can be adapted according to the computing power of electronic equipment, the resource availability of edge and cloud environments, or specific application requirements.

[0097] The spaceborne GNSS multipath modeling method first determines whether the signal intersects with the reflection plane through modeling and verifies whether reflection occurs. For signals that are reflected, the reflection path is determined, then the reflection point and reflection path are calculated, and finally the multipath delay of the reflected signal relative to the line-of-sight signal is calculated.

[0098] Figure 1 This is a flowchart illustrating an exemplary embodiment of a spaceborne GNSS multipath modeling method, such as... Figure 1 As shown, the method includes steps S1 to S4, which are described in detail below.

[0099] S1: In the same coordinate system, establish a three-dimensional model of the satellite and a signal source model to simulate the signal incident process. When the signal ray emitted by the signal source model intersects with the three-dimensional model of the satellite, it is confirmed that there may be a reflected signal.

[0100] In this embodiment, the purpose of step S1 is to establish a three-dimensional model, select a suitable coordinate system, establish a model for the platform where the satellite receiver is located, and establish a model for the signal source to simulate the incident process of the signal. When the signal intersects with the model, it is assumed that there may be a reflection.

[0101] In an exemplary embodiment, step S1 is implemented as follows:

[0102] S11: Determine the reference coordinate system of the satellite model, such as... Figure 2 As shown: with the satellite's center of mass as the origin, the coordinate axes are determined according to the satellite's attitude. The satellite platform is considered a rigid body with a specific shape and size, and the position of the onboard receiver's receiving antenna can be represented by three-dimensional coordinates. Reflecting surfaces that may generate multipath signals are identified, including planar and curved surfaces; taking the ENVISAT satellite as an example, possible reflecting surfaces are selected as follows... Figure 3 As shown, determine the plane equation and the curved surface equation of the reflecting surface.

[0103] S12: Select a GPS satellite as the signal source and represent the signal source location using rectangular coordinates in the satellite coordinate system (i.e., the reference coordinate system). Draw a mirror image of the receiving antenna about the reflecting surface, connect the mirror image of the signal source to the signal source, and if the mirror image intersects the plane, a reflection path exists.

[0104] S13: Determine if the ray intersects the plane. If the equations of the ray and the reflecting surface have solutions, it indicates that the ray intersects the reflecting surface, and reflection may occur. The ray equation can be determined based on the positions of the signal source and the receiving antenna. Generally, the ray equation is a straight line equation. After determining the position of the signal source and the mirror image position of the receiving antenna with respect to the reflecting surface, two points on the straight line equation are determined, and the equation can be derived from these two points.

[0105] Through steps S11 to S13 above, a satellite model, a source model, and a reflector model were established in the satellite coordinate system, and possible reflected signals were also preliminarily determined.

[0106] S2: Based on the intensity ratio before and after the signal ray passes through the reflection front of the satellite's three-dimensional model, the possible reflected signals are verified. If the intensity ratio is within the set range, the existence of the reflected signal is confirmed.

[0107] In this embodiment, step S2 is intended to verify the possible reflection signals identified in step S1.

[0108] In an exemplary embodiment, step S2 verifies the reflected signal, and the specific method is as follows:

[0109] Considering the phenomenon that signal rays can pass through the reflecting surface, causing incorrect LOS and NLOS estimates, the method of receiving signal strength threshold is used for verification.

[0110] GPS signals are electromagnetic waves, and in regions far from the source, they can be approximated as plane electromagnetic waves. According to the theory of reflection and refraction of electromagnetic waves in a medium, when the signal originates from the first medium (dielectric constant...),... magnetic permeability ) incident on the second medium (dielectric constant) magnetic permeability Assume the electric field strength of the incident wave is:

[0111] ;

[0112] The electric field strength of the reflected wave is:

[0113] ;

[0114] The electric field intensity of the refracted wave is:

[0115] ;

[0116] In the above formula, This represents the electric field strength of the incident wave. This represents the electric field strength of the reflected wave. This represents the electric field intensity of the refracted wave. Represents angular frequency. Represents the wave vector. λ represents wavelength. Represents the unit direction vector. Represents a spatial position vector. The scalar representing the electric field intensity of the incident wave. The electric field intensity scalar represents the reflected wave. The scalar quantity representing the electric field intensity of a refracted wave;

[0117] Based on the boundary conditions of Maxwell's equations, the reflection coefficient for vertical polarization (electric field vector perpendicular to the incident plane) can be obtained as follows:

[0118] ;

[0119] Refractive index:

[0120] ;

[0121] For the case of parallel polarization (electric field vector parallel to the incident plane), the reflection coefficient is:

[0122] ;

[0123] Refractive index:

[0124] ;

[0125] The formulas above for calculating the reflection and refraction coefficients of vertical and parallel polarization are as follows: For the angle of refraction, Fresnel's law applies: Calculated; Represents the reflection coefficient of vertical polarization. The refractive index represents the vertical polarization. This represents the dielectric constant of the first medium. Indicates the permeability of the first medium. This represents the dielectric constant of the second medium. This represents the permeability of the second medium; Indicates the angle of incidence.

[0126] Since the reflection coefficient of GPS signals on the reflection plane is between parallel polarization and vertical polarization, the signal intensity of the reflected rays is measured and the reflection coefficient is calculated. The signal within the above range is considered to be the reflected signal. The reflected rays are obtained according to the above method.

[0127] S3: Calculate the reflection point and reflection path when the reflected signal is present.

[0128] In an exemplary embodiment, the reflection point and reflection path are calculated using the following method:

[0129] After mirroring the signal source on the reflecting surface, the emission point is calculated by plotting the image. A schematic diagram is shown below. Figure 4 As shown in the figure S As a signal source, A For the receiving antenna, construct a mirror image of the receiving antenna with respect to the reflecting surface. Connected to the signal source, the intersection point is Take any point on the reflecting surface Q The reflection point can be obtained by the following formula:

[0130] ;

[0131] In the formula, Indicates the reflection point. Indicates the signal source. This represents the image of the receiving antenna with respect to the reflector. This indicates that the normal to the reflecting surface is in the opposite direction.

[0132] According to the law of reflection, the angle of reflection is equal to the angle of incidence, from which the reflection path can be obtained.

[0133] S4: Calculate the code pseudorange delay, carrier phase delay, and Doppler delay to obtain the multipath error model.

[0134] In one exemplary embodiment, such as Figure 5 The diagram shows the flowchart for establishing a multipath error model. Step S4 can be implemented using the following method:

[0135] Please combine Figure 4 Assuming the signal source S Location is Receiving antenna A Location is Reflection point Q The position is The normal of the reflecting surface for Receiving antenna A Mirror image relative to the reflecting surface The position is .

[0136] LOS and NLOS signals and The formula for calculating the geometric propagation distance is:

[0137] ;

[0138] ;

[0139] In the formula, This represents the geometric propagation distance of the LOS signal. This represents the vector between the signal source S and the receiving antenna A. , and These represent the receiving antennas. x Axis coordinates y Axis coordinates and z Axis coordinates , and These represent the locations of the signal sources. x Axis coordinates y Axis coordinates and z Axis coordinates Indicates the geometric propagation distance of the NLOS signal. This represents the vector between the signal source S and the reflection point Q. This represents the vector between the reflection point Q and the receiving antenna A. , and Representing the reflection points x Axis coordinates y Axis coordinates and z Axis coordinates;

[0140] With frequency as Taking GPS signals as an example, the code delay is determined by the distance. Ignoring the influence of differential code deviation, the delay is:

[0141] ;

[0142] ;

[0143] In the formula, Indicates the spreading code rate. Represents the speed of light. Indicates the code delay of the LOS signal. This indicates the code delay of the NLOS signal.

[0144] The carrier phase delay of the signal is:

[0145] ;

[0146] ;

[0147] In the formula, This indicates the carrier phase delay of the LOS signal. This indicates the carrier phase delay of the NLOS signal.

[0148] The carrier wavelength is defined as:

[0149] ;

[0150] In the formula It is the carrier frequency, defined as:

[0151] ;

[0152] in For the fundamental frequency, This is the carrier factor. For GPS signals, the carrier factor corresponding to the transmitted signal frequency at L1 is... When it is 154, L2 At 120, L5 It is 115.

[0153] The Doppler frequency shift is related to the relative orientation of the receiver and the signal source. The formula for calculating the Doppler frequency of a LOS signal is:

[0154] ;

[0155] In the formula, The Doppler frequency represents the line-of-sight signal. and These are the velocity vectors of the signal source and the receiving antenna, respectively. , and These represent the components of the signal source velocity vector along the x, y, and z axes, respectively. , and These represent the components of the receiving antenna velocity vector along the x, y, and z axes, respectively.

[0156] The formula for calculating the Doppler frequency of NLOS is:

[0157] ;

[0158] In the formula, This represents the Doppler frequency of the NLOS signal.

[0159] In NLOS Doppler calculations, the velocity of the signal reflection point is considered to be 0, and the frequency is derived using the above formula. i The amount of delay.

[0160] Distance delay for:

[0161] ;

[0162] Relative code pseudorange delay for:

[0163] ;

[0164] relative carrier phase delay for:

[0165] ;

[0166] Relative Doppler delay for:

[0167] ;

[0168] In summary, through ray tracing, the code pseudorange delay, relative carrier phase delay, and relative Doppler delay caused by multipath effects were obtained.

[0169] Figure 6 This is a structural diagram illustrating an exemplary embodiment of a spaceborne GNSS multipath modeling device. Embodiments of this application provide a spaceborne GNSS multipath modeling device, such as... Figure 6 As shown, the spaceborne GNSS multipath modeling device includes:

[0170] The model building module 601 is configured to build a satellite 3D model and a signal source model in the same coordinate system to simulate the signal incident process. When the signal ray emitted by the signal source model intersects with the satellite 3D model, it is confirmed that there may be a reflected signal.

[0171] The signal verification module 602 is configured to verify possible reflected signals based on the intensity ratio before and after the signal ray passes through the reflection surface of the satellite's three-dimensional model. If the intensity ratio is within a set range, the existence of the reflected signal is confirmed.

[0172] The reflection calculation module 603 is configured to calculate the reflection point and the reflection path when the reflection signal is present;

[0173] The multipath modeling module 604 is configured to calculate the code pseudorange delay, carrier phase delay, and Doppler delay to obtain a multipath error model.

[0174] The spaceborne GNSS multipath modeling device provided in this embodiment can be used to execute the above-mentioned spaceborne GNSS multipath modeling method. Its implementation principle and technical effect are similar, and will not be described again in this embodiment.

[0175] This application provides an electronic device that may include a processor and a memory, wherein the processor and the memory can communicate; for example, the processor and the memory communicate via a communication bus, the memory is used to store computer execution instructions, and the processor is used to call the computer execution instructions in the memory to execute the spaceborne GNSS multipath modeling method shown in any of the above method embodiments.

[0176] The aforementioned processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this application can be directly manifested as being executed by a hardware processor, or executed by a combination of hardware and software modules within the processor.

[0177] This application provides a computer-readable storage medium storing computer-executable instructions; when executed by a processor, the computer-executable instructions are used to implement the spaceborne GNSS multipath modeling method as described in any of the above embodiments.

[0178] This application provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-described spaceborne GNSS multipath modeling method.

[0179] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0180] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A spaceborne GNSS multipath modeling method, characterized in that, include: In the same coordinate system, a three-dimensional model of the satellite and a signal source model are established to simulate the incident process of the signal. When the signal ray emitted by the signal source model intersects with the three-dimensional model of the satellite, it is confirmed that there may be a reflected signal. Based on the intensity ratio of the signal ray before and after the reflection of the satellite's three-dimensional model, the possible reflected signals are verified. If the intensity ratio is within the set range, the existence of the reflected signal is confirmed. Calculate the reflection point and reflection path when the reflected signal is present; The code pseudorange delay, carrier phase delay, and Doppler delay are calculated to obtain the multipath error model, including: The Doppler frequency shift is related to the relative orientation of the receiving antenna and the signal source. The formula for calculating the Doppler frequency of a signal without reflection is: In the formula, This represents the Doppler frequency of the LOS signal. and These are the velocity vectors of the signal source and the receiving antenna, respectively. , and These represent the components of the signal source velocity vector along the x, y, and z axes, respectively. , and These represent the x-axis, y-axis, and z-axis components of the receiving antenna velocity vector, respectively. It is the carrier frequency; This represents the vector between the signal source S and the receiving antenna A. , and These represent the receiving antennas. x Axis coordinates y axis coordinates and z Axis coordinates , and These represent the locations of the signal sources. x Axis coordinates y axis coordinates and z Axis coordinates This represents the vector between the signal source S and the reflection point Q. This represents the vector between the reflection point Q and the receiving antenna A. , and Representing the reflection points x Axis coordinates y axis coordinates and z Axis coordinates; The formula for calculating the Doppler frequency of a reflected signal is: In the formula, Indicates the Doppler frequency of the NLOS signal; The distance delay is calculated using the following formula. : The relative code pseudorange delay is calculated using the following formula. : In the formula, Indicates the spreading code rate; The relative carrier phase delay is calculated using the following formula. : The relative Doppler delay is calculated using the following formula. : 。 2. The method according to claim 1, characterized in that, In the same coordinate system, a 3D model of the satellite and a signal source model are established to simulate the signal incident process. When the signal ray emitted by the signal source model intersects with the 3D model of the satellite, it is confirmed that a reflected signal may exist, including: Establish a reference coordinate system with the satellite's center of mass as the origin. Determine the direction of the coordinate axes based on the satellite's attitude. Treat the platform on which the satellite is located as a rigid body. Use three-dimensional coordinates to represent the position of the receiving antenna of the onboard receiver. Determine the reflecting surface that may generate multipath signals and determine the equation of the reflecting surface. Using GPS satellites as the signal source, the position of the signal source is represented by rectangular coordinates in the reference coordinate system. The receiving antenna is mirrored about the reflecting surface. The mirror image is connected to the signal source. If the line connecting the mirror image and the signal source intersects the reflecting surface, then a reflection path is determined to exist. In the presence of a reflection path, the ray equation is determined based on the positions of the signal source and the receiving antenna. When the ray equation has a solution to the reflection surface equation, it indicates that the signal ray intersects the reflection surface, confirming the possible existence of a reflected signal.

3. The method according to claim 2, characterized in that, The reflected signal is verified based on the intensity ratio before and after the signal ray passes through the reflection surface of the satellite's three-dimensional model. If the intensity ratio is within a set range, the presence of the reflected signal is confirmed. The reflection coefficient is calculated based on the measured signal intensity of the reflected ray. If the reflection coefficient is between the reflection coefficients of vertical polarization and parallel polarization, then the presence of the reflected signal is confirmed; wherein, vertical polarization means that the electric field vector is perpendicular to the incident surface, and parallel polarization means that the electric field vector is parallel to the incident surface; If the difference between the reflection coefficient and the refraction coefficient is within a set threshold range, then it is confirmed that the reflected signal does not exist.

4. The method according to claim 3, characterized in that, The reflection coefficients for vertical and parallel polarization are calculated using the following method: When a signal ray is incident from the first medium onto the second medium, the electric field intensity vectors of the incident wave, the reflected wave, and the refracted wave are calculated using the following formulas: In the formula, This represents the electric field strength of the incident wave. This represents the electric field strength of the reflected wave. This represents the electric field intensity of the refracted wave. Represents angular frequency. Represents the wave vector. λ represents wavelength. Represents the unit direction vector. Represents a spatial position vector. The scalar representing the electric field intensity of the incident wave. The electric field intensity scalar represents the reflected wave. The scalar quantity representing the electric field intensity of a refracted wave; Based on the boundary conditions of Maxwell's equations, the reflection coefficient and refraction coefficient of vertical polarization can be obtained using the following formulas: In the formula, Represents the reflection coefficient of vertical polarization. The refractive index represents the vertical polarization. This represents the dielectric constant of the first medium. Indicates the permeability of the first medium. This represents the dielectric constant of the second medium. Indicates the permeability of the second medium. Indicates the angle of refraction. Indicates the angle of incidence; Based on the boundary conditions of Maxwell's equations, the reflection coefficient and refraction coefficient of parallel polarization can be obtained using the following formula: In the formula, The reflection coefficient represents parallel polarization. The refractive index represents the parallel polarization. When the intensity ratio of the signal before and after the reflection surface is between the parallel polarization reflection index and the vertical polarization reflection index at the interface, the signal is confirmed to be a multipath signal with reflection.

5. The method according to claim 2, characterized in that, In the presence of the reflected signal, the reflection point and reflection path are calculated, including: Taking the intersection of the line connecting the mirror image and the signal source with the reflecting surface as the reflection point, and arbitrarily selecting a point on the reflecting surface... The reflection point is obtained using the following formula: In the formula, Indicates the reflection point. Indicates the signal source. This represents the image of the receiving antenna with respect to the reflector. This indicates that the normal to the reflecting surface is in the opposite direction; According to the law of reflection, the angle of reflection equals the angle of incidence, and the reflection path can be obtained from this.

6. The method according to claim 1, characterized in that, The code pseudorange delay, carrier phase delay, and Doppler delay are calculated to obtain the multipath error model, including: The geometric propagation distance between LOS and NLOS signals can be calculated using the following formula: In the formula, This represents the geometric propagation distance of the LOS signal. Indicates the geometric propagation distance of the NLOS signal; For frequency The code delay of a GPS signal is determined by distance. Without considering the influence of differential code deviation, the code delay can be calculated using the following formula: In the formula, Indicates the code delay of the LOS signal. Indicates the code delay of the NLOS signal; The carrier phase delay of the signal is calculated using the following formula: In the formula, This indicates the carrier phase delay of the LOS signal. This indicates the carrier phase delay of the NLOS signal; The carrier wavelength is defined as: In the formula, Defined as: In the formula, For the fundamental frequency, This is the carrier factor.

7. A spaceborne GNSS multipath modeling device, characterized in that, The device includes: The model building module is configured to build a satellite 3D model and a signal source model in the same coordinate system to simulate the signal incident process. When the signal ray emitted by the signal source model intersects with the satellite 3D model, it is confirmed that there may be a reflected signal. The signal verification module is configured to verify possible reflected signals based on the intensity ratio before and after the signal ray passes through the reflection surface of the satellite's three-dimensional model. If the intensity ratio is within a set range, the existence of the reflected signal is confirmed. The reflection calculation module is configured to calculate the reflection point and reflection path in the presence of the reflected signal; The multipath modeling module is configured to calculate code pseudorange delay, carrier phase delay, and Doppler delay to obtain a multipath error model, including: The Doppler frequency shift is related to the relative orientation of the receiving antenna and the signal source. The formula for calculating the Doppler frequency of a signal without reflection is: In the formula, This represents the Doppler frequency of the LOS signal. and These are the velocity vectors of the signal source and the receiving antenna, respectively. , and These represent the components of the signal source velocity vector along the x, y, and z axes, respectively. , and These represent the x-axis, y-axis, and z-axis components of the receiving antenna velocity vector, respectively. It is the carrier frequency; This represents the vector between the signal source S and the receiving antenna A. , and These represent the receiving antennas. x Axis coordinates y axis coordinates and z Axis coordinates , and These represent the locations of the signal sources. x Axis coordinates y axis coordinates and z Axis coordinates This represents the vector between the signal source S and the reflection point Q. This represents the vector between the reflection point Q and the receiving antenna A. , and Representing the reflection points x Axis coordinates y axis coordinates and z Axis coordinates; The formula for calculating the Doppler frequency of a reflected signal is: In the formula, Indicates the Doppler frequency of the NLOS signal; The distance delay is calculated using the following formula. : The relative code pseudorange delay is calculated using the following formula. : In the formula, Indicates the spreading code rate; The relative carrier phase delay is calculated using the following formula. : The relative Doppler delay is calculated using the following formula. : 。 8. An electronic device, characterized in that, The electronic device includes: a processor and a memory; the memory is used to store instructions; the processor is used to execute the instructions in the memory, causing the electronic device to perform the method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1 to 6.

10. A computer program product, characterized in that, It includes a computer program that, when executed by a processor, implements the method as described in any one of claims 1 to 6.

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