CN112070894A - Real environment navigation multipath real-time simulation method, device, medium and electronic equipment - Google Patents
Real environment navigation multipath real-time simulation method, device, medium and electronic equipment Download PDFInfo
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Abstract
The invention discloses a real environment navigation multipath real-time simulation method, a device, a medium and electronic equipment, wherein the method comprises the following steps: updating a real-time scene according to real-time dynamic parameters of a receiver carrier, a receiver antenna and a visible satellite; calculating direct paths and diffraction multipath paths set DiffractPaths of satellite signals reaching the antenna of the receiver; obtaining all reflection/transmission multipath path sets MultiPaths at one time by using a test RAY set RAY; calculating power attenuation, time delay and Doppler data according to the set MultiPaths, the set DiffractPaths, direct path coordinates and the like; generating a simulated navigation signal according to the power attenuation, the time delay and the Doppler data to perform multi-path real-time simulation; and repeating the steps according to a set updating period until the simulation is finished. The invention improves the updating rate and the real-time performance when the navigation multipath simulation is carried out in a complex 3D scene.
Description
Technical Field
The invention relates to the technical field of satellite navigation simulators, in particular to a real environment navigation multipath real-time simulation method, a device, a medium and electronic equipment.
Background
The satellite navigation positioning technology is widely applied in a plurality of fields, however, the positioning accuracy is affected by errors generated by multipath effects, the satellite navigation positioning technology is one of important error sources of a satellite navigation system, under severe conditions, errors caused by multipath signals to code tracking can reach the magnitude of several meters or even dozens of meters, and multipath modeling and multipath elimination technologies are always research hotspots in the field of satellite navigation.
The existing multipath modeling Method is mainly divided into a modeling Method based on a statistical model And a modeling Method based on a deterministic model, wherein the modeling Method based on the statistical model has poor applicability And low prediction accuracy, And the modeling Method based on the deterministic model is widely applied to Ray Tracing models such as a mirror Image Method (Image), a Ray Tracing Method (Ray Tracing Method), a bounce Ray Method (SBR), a Ray tube Method And the like at present, And calculates the reflection, diffraction, shielding And the like of satellite signals in a 3D environment by combining geometric optics And a consistency diffraction theory, but the Method is relatively accurate And can simulate any type of scene, but the following problems still exist at present And need to be solved:
1. the scene complexity is high: three-dimensional environments contain hundreds of thousands to millions of triangles, and performing a large number of collision detections in complex scenes is a huge challenge.
2. Calculating the combined explosive growth: under the combined conditions of multiple satellites and multiple receiver antennas, all paths between each antenna and each satellite need to be simulated, that is, if there are 50 satellites and 2 receiver antennas, all reflection and diffraction paths between 50 × 2 transmitting points and receiving points need to be calculated, which even leads to the calculation combination increase with the increase of the number of reflections.
3. Dynamic scene: that is, the receiver and the satellite are constantly updating the position, and the receiver carrier, the crowd, the vehicle, etc. are changing, so that the ray tracing acceleration structure needs to be updated frequently, and in terms of the current technology, the time consumption for updating the acceleration structure can reach tens of milliseconds to hundreds of milliseconds.
4. High update rate and real-time: the calculation frequency of the navigation simulation on the parameters is higher, generally not lower than 100Hz, namely, the system needs to calculate all the parameters once every 10 milliseconds, and only if the calculation time of each multipath simulation calculation is within 10 milliseconds, the real-time online simulation can be carried out.
In summary, in the prior art, it is difficult to realize real-time and high-update-rate calculation in the navigation multipath simulation.
Disclosure of Invention
The invention provides a real environment navigation multipath real-time simulation method, which aims to solve the technical problem that the high update rate and real-time performance are influenced by huge calculation amount in a complex 3D scene with a plurality of receivers and a plurality of navigation satellites in the conventional navigation multipath simulation mode.
The technical scheme adopted by the invention is as follows:
a real environment navigation multipath real-time simulation method comprises the following steps:
according to the simulated real-time dynamic parameters of the receiver carrier, the receiver antenna and all the visible satellites at the current simulation moment, carrying out real-time scene updating on the 3D simulation scene of the real environment;
calculating a direct path and each diffraction path of the satellite signal reaching the receiver antenna to obtain a diffraction multipath path set DiffractPaths;
performing RAY tracking by using a preset test RAY set RAY to obtain a multi path set of reflection/transmission multi paths from all satellites to a receiver antenna at one time, wherein all test RAYs in the test RAY set RAY are distributed on a unit spherical surface and point to the spherical surface by taking the position of the receiver antenna as the center of a sphere, and the maximum included angle between adjacent test RAYs is taken asθ ray ；
Calculating power attenuation, time delay and Doppler data of each direct and multipath signal of the satellite reaching the receiver antenna according to each path coordinate in a reflection/transmission multipath path set MultiPaths, each path coordinate in a diffraction multipath path set DiffractPaths, direct path coordinates, a signal transmission path, a reflection/transmission coefficient of a reflection point, satellite speed, receiver antenna speed, a satellite antenna directional diagram and a receiver antenna directional diagram;
generating direct and multipath simulated navigation signals based on the current 3D simulation scene according to the power attenuation, the time delay and the Doppler data to perform multipath real-time simulation;
and repeating the steps according to a set updating period until the simulation is finished.
Further, before real-time scene updating is performed on a 3D simulation scene of a real environment according to the simulated real-time dynamic parameters of the receiver carrier, the receiver antenna, and the current simulation time of all visible satellites, the method further includes the steps of:
performing 3D modeling on a real environment, and expressing the real environment as triangular grid data in a set coordinate system, wherein the triangular grid data comprises a reflection coefficient, a transmission coefficient and an object ID;
dividing each triangular mesh into a static mesh and a dynamic mesh according to the position change condition in the simulation process and then respectively storing the static mesh and the dynamic mesh;
respectively establishing a static GPU ray detection acceleration structure and a dynamic GPU ray detection acceleration structure for the static grids and the dynamic grids;
and extracting static and dynamic diffraction edge data from the static grids and the dynamic grids respectively, and storing the data in a dynamic GPU diffraction edge storage area and a static GPU diffraction edge storage area respectively.
Further, the real-time scene updating of the 3D simulation scene of the real environment according to the simulated real-time dynamic parameters of the receiver carrier, the receiver antenna, and the current simulation time of all visible satellites specifically includes the steps of:
setting a motion track of a simulated receiver carrier and configuration parameters of a receiver antenna, wherein the motion track comprises track, coordinates, postures and speed information of the receiver carrier, and the configuration parameters comprise relative position, posture, an antenna directional diagram and polarization mode information of the antenna on the receiver carrier;
acquiring coordinates and attitude information of a receiver carrier and a receiver antenna at the current moment according to the motion track of the receiver carrier, acquiring coordinates and speed of all visible satellites at the current simulation moment from a navigation simulator or a satellite operation simulation module, and converting coordinate data into a coordinate system corresponding to a triangular grid;
generating a transformation matrix through the coordinate and attitude information of a receiver carrier and a dynamic object, and applying the transformation matrix to carry out rotation and movement transformation on a dynamic grid and a dynamic diffraction edge so as to realize real-time scene updating of a 3D simulation scene;
and updating the transformed dynamic grid data and dynamic diffraction edge data to a dynamic GPU ray detection acceleration structure and a dynamic GPU diffraction edge storage area respectively.
Further, each diffraction path of the satellite signal reaching the receiver antenna is calculated to obtain a diffraction multipath path set diffactpaths, and the method specifically comprises the following steps:
and traversing all static and dynamic diffraction edges in parallel, calculating diffraction points of each satellite signal reaching each receiver antenna through each diffraction edge according to a unified diffraction theory, and adding corresponding diffraction paths into a diffraction multipath path set DiffractPaths if the diffraction points exist.
Furthermore, the test RAYs in the test RAY set RAY are uniformly distributed on the spherical surface, and the included angles between adjacent test RAYs are equal to the maximum included angleθ ray The same;
or,
the distribution density of the test RAYs in different areas of the spherical surface in the test RAY set RAY is in direct proportion to the probability of the occurrence of the multipath in each area.
Further, RAY tracking is carried out by utilizing a preset test RAY set RAY, and reflection/transmission multipath path sets MultiPaths from all satellites to receiver antennas are obtained at one time, and the method specifically comprises the following steps:
traversing the testing RAY set RAY in parallel, taking the receiver antenna as a starting point, taking the testing RAYs in the testing RAY set RAY as directions, tracking the reflection/transmission multipath paths when the RAYs pass through the triangular grid, and forming all potential reflection/transmission multipath path sets TracingPaths which reach the receiver antenna;
traversing paths in the set TracingPaths in parallel, and calculating the included angle between the final reflection or transmission direction of the paths and the opposite direction of each satellite signalθ sIf, ifθ s ≤θ ray Then the path and the paired satellite are added to the set of reflected/transmitted multipath paths MultiPaths.
Further, RAY tracking is performed by using a preset test RAY set RAY, and a multi paths set of reflection/transmission multipath paths from all satellites to the receiver antenna is obtained at one time, and the method specifically comprises the following steps:
according to the geometrical optics principle, correcting coordinates of all paths in the set of MultiPaths on the reflection triangular meshes and the transmission triangular meshes are calculated in parallel, if the correcting coordinates fall into the corresponding reflection triangular meshes and transmission triangular meshes, the paths are valid, the corrected coordinates are used for replacing original coordinates of reflection points and refraction points, if the correcting coordinates fall out of the corresponding reflection triangular meshes and transmission triangular meshes, the paths are invalid, and the paths are discarded.
Further, RAY tracking is performed by using a preset test RAY set RAY, and a multi paths set of reflection/transmission multipath paths from all satellites to the receiver antenna is obtained at one time, and the method specifically comprises the following steps:
the paths in the corrected set of MultiPaths are path simplified to eliminate similar paths in the reflected/transmitted multipath paths between the same set of satellites and receiver antennas.
Further, the path simplification of the paths in the corrected collective MultiPaths to eliminate similar paths in the reflection/transmission multipath paths between the same group of satellites and the receiver antennas specifically includes the steps of:
classifying the reflection/transmission multipath paths among the same group of satellites and receiver antennas in the corrected set MultiPaths, and if the paths have the same reflection/transmission structure and the difference of the path turning angles corresponding to the reflection/transmission points is smaller than a set threshold value, classifying the paths into the same class;
selecting angles among reflecting/transmitting multipath paths in the same classθ sThe smallest one is taken as the best path and the remaining paths are discarded.
Further, the number of the test RAYs in the test RAY set RAY is greater than 10000, and is directly proportional to the calculation accuracy.
Further, after calculating a direct path and each diffraction path of the satellite signal reaching the receiver antenna to obtain a set of diffraction multipath paths diffactpaths, the method further comprises the following steps:
detecting a direct path shielding state between the satellite and the receiver antenna by using rays, and discarding a shielded invalid path;
the ray detection is used to detect the occlusion state of each path in the set of diffracted multipath paths diffactpaths, and the invalid paths occluded therein are discarded.
In another aspect, the present invention provides a real environment navigation multipath real-time simulation apparatus, which includes:
the scene updating module is used for updating the real-time scene of the 3D simulation scene of the real environment according to the simulated real-time dynamic parameters of the receiver carrier, the receiver antenna and the current simulation time of all the visible satellites;
the direct and diffraction calculation module is used for calculating direct paths and various diffraction paths of the satellite signals reaching the receiver antenna to obtain a diffraction multipath path set DiffractPath;
a RAY set tracking module for performing RAY tracking by using a preset test RAY set RAY to obtain a multi path set of reflection/transmission multi paths from all satellites to a receiver antenna at one time, wherein each test RAY in the test RAY set RAY is distributed on a unit spherical surface and points to the spherical surface by taking the position of the receiver antenna as the center of the sphere, and the maximum included angle between adjacent test RAYs isθ ray ；
The signal arrival parameter calculation module is used for calculating power attenuation, time delay and Doppler data of each direct and multipath signal of the satellite reaching the receiver antenna according to each path coordinate in the reflection/transmission multipath path set MultiPaths, each path coordinate in the diffraction multipath path set DiffractPaths, direct path coordinates, a signal transmission path, reflection/transmission coefficients of reflection points, satellite speed and receiver antenna speed, a satellite antenna directional diagram and a receiver antenna directional diagram;
the analog navigation signal generation module is used for generating direct and multipath analog navigation signals based on the current 3D simulation scene according to the power attenuation, the time delay and the Doppler data to perform multipath real-time simulation;
and the period advancing module is used for carrying out multi-path real-time simulation according to a set updating period until the simulation is finished.
Another aspect of the present invention provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the real environment navigation multipath real-time simulation method.
In another aspect, the present invention provides a storage medium, where the storage medium includes a stored program, and when the program runs, the apparatus on which the storage medium is located is controlled to execute the steps of the real environment navigation multipath real-time simulation method.
The invention has the following beneficial effects:
in the real-environment navigation multipath real-time simulation method, the device, the medium and the electronic equipment, the unique test RAY set RAY is utilized to perform the test RAY back tracking of the antenna of the receiver, and all reflection/transmission multipath paths of the receiver and all satellites can be obtained by one-time tracking, so that the influence of the increase of the number of the satellites on the calculation time consumption is small, the time consumption is reduced to constant time from the multiple relation of the number of the satellites, the calculation amount is greatly reduced, the calculation time is ensured to be within 10 milliseconds each time, and the updating rate and the real-time performance of the navigation multipath simulation in the complex 3D scene of a plurality of receivers and a plurality of navigation satellites are improved.
In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a flow chart of a real environment navigation multipath real-time simulation method according to a preferred embodiment of the present invention.
Fig. 2 is a schematic diagram of the steps of 3D modeling of a real environment according to a preferred embodiment of the present invention.
FIG. 3 is a schematic diagram of the extraction of diffraction edges from a 3D simulation scene according to the preferred embodiment of the invention.
Fig. 4 is a flowchart illustrating detailed sub-steps of step S1 in fig. 1.
Fig. 5 is a schematic diagram of motion trajectory simulation when a vehicle is used as a receiver carrier.
Fig. 6 is a schematic diagram of a motion trajectory simulation when an airplane is used as a receiver carrier.
Figure 7 is a schematic diagram of the steps of the diffractive multipath path computation of the preferred embodiment of the present invention.
Figure 8 is a diffraction point diagram of a preferred embodiment of the present invention.
FIG. 9 is a schematic diagram of RAY RAY tracing steps for a test RAY set in accordance with a preferred embodiment of the present invention.
FIG. 10 is a RAY RAY tracing simulation diagram of a test RAY set according to a preferred embodiment of the present invention.
Fig. 11 is a schematic diagram of the path correction procedure according to the preferred embodiment of the present invention.
Fig. 12 is a schematic diagram of the path simplification steps of the preferred embodiment of the present invention.
Fig. 13 is a detailed sub-step diagram of step S34 in accordance with the preferred embodiment of the present invention.
Fig. 14 is a simplified reflected/transmitted multipath path diagram of the preferred embodiment of the present invention.
FIG. 15 is a diagram illustrating the direct and diffracted multipath path occlusion detection steps of the preferred embodiment of the present invention.
Fig. 16 is a diagram illustrating processed multipath path simulation between a receiver and a satellite according to a preferred embodiment of the present invention.
Fig. 17 is a schematic block diagram of a multipath real-time simulation apparatus according to a preferred embodiment of the present invention.
Fig. 18 is a block diagram of an electronic device entity in accordance with a preferred embodiment of the present invention.
Fig. 19 is an internal structural view of a computer apparatus of the preferred embodiment of the present invention.
Fig. 20 is a connection block diagram of a real environment navigation multipath real-time simulation device and a simulated navigator according to a preferred embodiment of the present invention.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
Referring to fig. 1, a preferred embodiment of the present invention provides a real environment navigation multipath real-time simulation method, including the steps of:
s1, updating the real-time scene of the 3D simulation scene of the real environment according to the simulated real-time dynamic parameters of the receiver carrier, the receiver antenna and the current simulation time of all visible satellites;
s2, calculating a direct path and each diffraction path of the satellite signal reaching the receiver antenna to obtain a diffraction multipath path set DiffractPaths;
s3, performing RAY tracking by using a preset testing RAY set RAY to obtain a multi path set from all satellites to receiver antennas at one time, wherein each testing RAY in the testing RAY set RAY is distributed on a unit spherical surface and points to the spherical surface by taking the position of the receiver antenna as the center of the sphere, and the maximum included angle between adjacent testing RAYs isθ ray ；
S4, calculating power attenuation, time delay and Doppler data of each direct and multipath signal of the satellite reaching the receiver antenna according to each path coordinate in the set MultiPaths, each path coordinate in the diffraction multipath Path set DiffractPaths, direct path coordinates, signal transmission paths, reflection/transmission coefficients of reflection points, satellite and receiver antenna speeds, a satellite antenna directional diagram and a receiver antenna directional diagram;
s5, generating direct and multipath simulated navigation signals based on the current 3D simulation scene according to the power attenuation, the time delay and the Doppler data to perform multipath real-time simulation;
s6, repeating the steps S1-S5 every 10 ms until the simulation is finished.
In the real-environment navigation multipath real-time simulation method of the embodiment, a unique test RAY set RAY is used for carrying out test RAY back tracking on a receiver antenna, all reflection/transmission multipath paths of the receiver and all visible satellites can be obtained by one-time tracking, the influence of the increase of the number of the satellites on the calculation time consumption is small, the time consumption is reduced from the multiple relation of the number of the satellites to constant time, the calculation amount is greatly reduced, the calculation time is guaranteed to be within 10 milliseconds each time, and the updating rate and the real-time performance of the navigation multipath simulation in the complex 3D scene of a plurality of receivers and a plurality of navigation satellites are improved. Practice proves that in the case of high load: in a complex scene with multiple satellites, multiple carriers, multiple antennas and millions of triangles, the signal calculation of simulating each satellite of each antenna for up to 32 paths of multipath and reflecting times for up to 6 times can be finished in real time, and the operation speed of the simulation system meets the real-time calculation requirement of 100Hz update rate.
As shown in fig. 2, in a preferred embodiment of the present invention, before performing real-time scene update on a 3D simulation scene of a real environment according to real-time dynamic parameters of a simulated receiver carrier, a receiver antenna, and a current simulation time of all visible satellites, the method further includes the steps of:
s101, performing 3D modeling on a real environment, and representing the real environment as triangular grid data in an NEU (North-East-Up, northeast local coordinate system) coordinate system, wherein the triangular grid data comprises a reflection coefficient, a transmission coefficient and an object ID;
s102, dividing each triangular mesh into a static mesh and a dynamic mesh according to the position change condition in the simulation process and then respectively storing the static mesh and the dynamic mesh;
s103, respectively establishing a static GPU ray detection acceleration structure and a dynamic GPU ray detection acceleration structure for the static grids and the dynamic grids;
and S104, extracting static diffraction edge data and dynamic diffraction edge data from the static grids and the dynamic grids respectively (see figure 3), and storing the static diffraction edge data and the dynamic diffraction edge data in a dynamic GPU diffraction edge storage area and a static GPU diffraction edge storage area respectively.
In this embodiment, scene modeling is performed on a real environment, and there are three types of scene generation methods:
the method comprises the following steps that 1, three-dimensional modeling is conducted on an air-ground integrated image based on unmanned aerial vehicle aerial photography, and then the three-dimensional modeling is conducted into a software system;
2, a manual scene building generation mode based on an external import model is adopted, and a user freely builds a required scene;
and 3, a real-time dynamic scene generation mode based on global elevation data and GIS (geographic information System) data of a map company, and software automatically generates a terrain grid near a receiver in real time through the elevation data and the GIS data (such as building outlines).
In the scene modeling of this embodiment, the coordinate system used is an NEU (North-East-Up, northeast local coordinate system) with the scene center as the origin, and in the 3 rd type of scene, the NEU origin of coordinates is variable in the operation process, that is, the position of the NEU origin of coordinates is switched every 10 kilometers.
The scene modeling also comprises the setting of reflection coefficient and transmission coefficient of the scene object, all objects in the scene (including buildings, terrain and navigation receiver model) are converted into triangular grid data in the NEU coordinate system, and the triangular grid data contains the reflection coefficient, the transmission coefficient, the object ID and other data for subsequent calculation.
In addition, in the embodiment, when performing 3D modeling on a real environment, the mesh of a static object and the mesh of a dynamic object are separated, and a separation update mechanism is established, that is, a triangular mesh in a scene is separated into a static mesh and a dynamic mesh for storage, the static mesh is an object mesh with a position unchanged in a simulation process of a building model, a terrain and the like in the scene, and the dynamic mesh is an object mesh with a position changed, such as a model of a navigation receiver and a model of a moving object. Meanwhile, a static GPU ray detection acceleration structure and a dynamic GPU ray detection acceleration structure are respectively and correspondingly established for the static grids and the dynamic grids, in the scene updating process, the static grids with large triangular grid number ratio do not need to be updated, and the scene can be updated in real time only by updating the dynamic grids with small triangular grid number ratio and the dynamic GPU ray detection acceleration structure, so that the problem of serious high time consumption caused by rebuilding of all acceleration structures in the prior art is solved.
In practice, after the grid is changed, a corresponding GPU ray detection acceleration structure needs to be reconstructed, and this operation takes time seriously when the number of grids is large, which may reach tens to hundreds of milliseconds. The separated GPU ray detection acceleration structure can solve the problem of high time consumption caused by dynamic object updating in a large-scale scene, the number of static grids in the triangular grids accounts for the vast majority of the total number of the triangular grids and is kept unchanged in the simulation process, so that the static GPU ray detection acceleration structure corresponding to the static grids does not need to be frequently updated, the dynamic grids need to be frequently updated in the simulation process, but the dynamic grids account for less in all the triangular grids, so that the time consumption of updating each time is small, the separated updating mechanism can minimize the updating time of the GPU ray detection acceleration structure, avoid serious high time consumption caused by rebuilding the acceleration structure, and improve the real-time performance of scene updating.
As shown in fig. 4, in a preferred embodiment of the present invention, the step S1 specifically includes the steps of:
s111, setting a motion track of a simulated receiver carrier and configuration parameters of a receiver antenna, wherein the motion track comprises track, coordinate, attitude and speed information of the receiver carrier, and the configuration parameters comprise relative position, attitude, antenna directional diagram and polarization mode information of the antenna on the receiver carrier;
s112, obtaining coordinates and posture information of a receiver carrier and a receiver antenna at the current moment according to the motion track of the receiver carrier, obtaining coordinates and speed of all visible satellites at the current simulation moment from the navigation simulator, and converting coordinate data into an NEU (North-East-Up, northeast local coordinate system) coordinate system of a triangular grid;
s113, generating a transformation matrix through the coordinate and attitude information of the receiver carrier and the dynamic object, and applying the transformation matrix to carry out rotation and movement transformation on the dynamic grid and the dynamic diffraction edge so as to realize real-time scene updating of the 3D simulation scene;
and S114, updating the transformed dynamic grid data and dynamic diffraction edge data to the dynamic GPU ray detection acceleration structure and the dynamic GPU diffraction edge storage area respectively.
In the embodiment, all the parameters such as the coordinates and the speed of the visible satellite at the current simulation time are acquired from the navigation simulator, and in addition, all the parameters such as the coordinates and the speed of the visible satellite at the current simulation time are acquired from the navigation simulator, and all the parameters such as the coordinates and the speed of the visible satellite at the current simulation time can also be acquired directly through a satellite operation simulation module which is established in advance, namely, the navigation simulator does not need to be connected during simulation, the parameters are directly acquired from the satellite operation simulation module which is established in advance, and the establishment of a simulation system is simplified.
When the motion trail of the simulated receiver carrier is set, one or more navigation receiver carrier motion trails can be established according to requirements, the motion trail of each receiver carrier can be configured independently, for example, the motion trail of a vehicle as the receiver carrier is shown in fig. 5, and the motion trail of an airplane as the receiver carrier is shown in fig. 6. The motion trail contains the motion control parameters and attitude information of the receiver carrier, and the motion trail can be set in a 3D simulation scene through a built-in trail editor in the scene, so that the self-defined editing and dynamics automatic calculation functions of the attitude can be provided.
Common receiver carrier types include: people, vehicles, airplanes, unmanned aerial vehicles, naval vessels, guided missiles, low orbit satellites, etc., different carriers correspond different carrier 3D models, wherein, receiver carrier model can be divided into two types: 1. built-in carrier models such as pedestrians, automobiles, helicopters, fighters, satellites and the like. 2. And (3) loading a custom model by a user, and supporting loading of models made by other tool software, such as 3DS, SKP, OBJ, FBX and the like. One or more receiver antennas can be mounted on the receiver carrier, and the relative positions and postures of the receiver antennas on the receiver carrier can be configured independently. When setting the configuration parameters of the receiver antenna, the antenna directional patterns, polarization modes and the like of the satellite and the receiver antenna can be configured. The receiver antenna may be mounted anywhere on the receiver carrier, which may mount one or more antennas.
In the embodiment, when the scene is updated, the transformation matrix is generated through the coordinate and posture information of the receiver carrier and the dynamic object, the transformation matrix is applied to only carry out rotation and movement transformation on the dynamic grids and the dynamic diffraction edges, and the real-time scene updating of the 3D simulation scene is realized. Meanwhile, the converted dynamic grid data and dynamic diffraction edge data are respectively updated to the dynamic GPU ray detection acceleration structure and the dynamic GPU diffraction edge storage area, so that a foundation is laid for subsequent updating calculation, and the data storage and reading time is shortened.
As shown in fig. 7, in the preferred embodiment of the present invention, each diffraction path of the satellite signal reaching the receiver antenna is calculated to obtain a set of diffraction multipath paths diffactpaths, which specifically includes the following steps:
s21, traversing all static and dynamic diffraction edges in parallel, calculating the diffraction point of each satellite signal reaching each receiver antenna through each diffraction edge according to the unified diffraction theory, and adding the corresponding diffraction path into the diffraction multipath path set DiffractPaths if the diffraction point exists.
In this embodiment, for subsequent calculation of the diffracted multipaths, before traversing all static and dynamic diffracted arrises in parallel, static and dynamic diffracted arrises data are extracted from the modeled static grid and dynamic grid by an automatic diffracted edge extraction algorithm and stored in the dynamic GPU diffracted arrise storage area and the static GPU diffracted arrise storage area, respectively.
Set the receiver antennas as
Set of satellites
The test rays are set as
The collection of scene diffraction edges (including static and dynamic diffraction edges) is
In the storage area of the GPU diffraction edge, starting a GPU kernel to traverse all the diffraction edges in parallel, and calculating all primary diffraction multipath paths from each satellite to each receiver antenna, wherein the specific method comprises the following steps:
building collections
Enabling GPU kernel to process set elements in parallel
: computing satellitesThe signal passing through the diffraction edgeeIs diffracted and reaches the receiver antennaaIf a diffraction point X is present, will diffract a path(s) < 2 >a，(X)，s) Adding to a set of diffractive multipath paths
All valid diffracted multipath paths are obtained, as shown in figure 8.
In a preferred embodiment of the present invention, when calculating diffraction points of each satellite signal reaching each receiver antenna through each diffraction edge, the diffraction edges are extracted from the scene grid, and the extracted diffraction edges satisfy the following condition: the included angle of two triangular surfaces connected with the diffraction edge is smaller than a set included angle threshold value, the length of the diffraction edge is larger than a set length threshold value, a general included angle threshold value is set to be 90 degrees, and a length threshold value is set to be 1 meter.
As shown in fig. 9, in the preferred embodiment of the present invention, a preset test RAY set RAY is used for RAY tracking, and a multi paths set of reflection/transmission multi paths from all satellites to the receiver antenna is obtained at one time, which specifically includes the steps of:
s31, traversing the testing RAY set RAY in parallel, taking the receiver antenna as a starting point, taking the testing RAYs in the testing RAY set RAY as directions, tracking the reflection/transmission multipath paths when the RAYs pass through the triangular grid, and forming all potential reflection/transmission multipath path sets TracingPaths (see figure 10) reaching the receiver antenna;
s32, traversing each path in the TracingPaths set in parallel, and calculating the included angle between the final reflection or transmission direction of the path and the opposite direction of each satellite signalθ sIf, ifθ s ≤θ ray Then the path and the paired satellite are added to the multi-reflection/transmission multi-path.
In the embodiment, firstly, a unique test RAY set RAY is utilized to perform the test RAY back tracking of the antenna of the receiver, and all potential reflection/transmission multipath path sets TracingPaths of the receiver and all satellites can be obtained by one-time tracking; since the angle between the final reflection direction of the test RAY in the test RAY set RAY and the opposite direction of each satellite signal is calculated for the paths in the set TracingPathsθ sWhen there is an included angle corresponding to the pathθ s >θ ray If the path is not associated with any satellite, the path is an invalid path, and the path needs to be eliminated, so that a path only paired with the satellite is obtained and added to the reflection/transmission multipath paths MultiPaths, the invalid path is reduced, and the efficiency of subsequent calculation is improved.
As shown in fig. 11, in the preferred embodiment of the present invention, a preset test RAY set RAY is used for RAY tracking, and a set of MultiPaths of reflection/transmission multipath paths from all satellites to the receiver antenna is obtained at one time, which specifically includes the following steps:
s33, according to the geometrical optics principle, correcting coordinates of all paths in the set of MultiPaths on the reflection triangular meshes and the transmission triangular meshes are calculated in parallel, if the correcting coordinates fall into the corresponding reflection triangular meshes and transmission triangular meshes, the paths are valid, the corrected coordinates are used for replacing original coordinates of reflection points and refraction points, and if the correcting coordinates fall out of the corresponding reflection triangular meshes and transmission triangular meshes, the paths are invalid, and the paths are discarded.
Because the discreteness of the test ray set and the matching between the path and the satellite are not exactly matched, the validity judgment and the path coordinate correction are further performed on the paths in the MultiPaths set by adopting the mirror image method geometric optics principle on the basis of the matching between the satellite and the test ray set in step S32, so that the accurate path coordinate of the multipath path is obtained, and the simulation accuracy is improved.
As shown in fig. 12, in the preferred embodiment of the present invention, a preset test RAY set RAY is used for RAY tracking, and a set of MultiPaths of reflection/transmission multipath paths from all satellites to the receiver antenna is obtained at one time, which specifically includes the following steps:
and S34, simplifying paths in the corrected set MultiPaths, and eliminating similar paths in reflection/transmission multipath paths among the same group of satellites and receiver antennas.
In this embodiment, after the paths in the set of MultiPaths are subjected to the satellite pairing, validity judgment and coordinate correction, many similar or identical paths still exist between the same group of satellites and the receiver antennas, and the existence of these similar or identical paths will cause the subsequent multipath paths to include multiple repeated paths.
As shown in fig. 13, in a preferred embodiment of the present invention, the step S34 specifically includes the steps of:
s341, classifying the reflection/transmission multipath paths among the same group of satellites and receiver antennas in the corrected set MultiPaths, if the paths have the same pathWhen the difference between the turning angles of the paths corresponding to the reflection/transmission points is smaller than a set threshold, for example, the threshold can be set to 2 ×θ ray Then, they are classified into the same class, so that the threshold is set to 2 ×, optionallyθ ray Because the angles at which the potential multipath paths match the satellite and the angles between the test rays are both anglesθ ray I.e. error between similar rays andθ ray has relevance.
S342, selecting included angles in similar paths in the same classθ sThe smallest one is taken as the best path and the remaining paths are discarded.
In this embodiment, to determine similar paths, the paths between the same satellite and the receiver antenna are classified according to corresponding rules, for example, the paths having the same reflection/transmission structure and the difference between the turning angles of the paths corresponding to the reflection/transmission points are all smaller than the set threshold 2 ×θ ray And if the paths are not eliminated, the paths are repeated and occupy excessive computing resources meaninglessly, so that the time consumption of unnecessary computation is increased. Therefore, after finding similar paths in the same class, the present embodiment selects an included angle among the similar paths in the same classθ sThe smallest one is the best path for this type of similar path, the remaining paths are discarded, and the simplified reflection/transmission multi-path is shown in fig. 14. The embodiment eliminates the repeated path between the same group of satellites and the receiver antenna by effectively classifying and selecting the optimal path between the same group of satellites and the receiver antenna, thereby eliminating the repeated path caused by the discreteness calculation error of the system, and simultaneously, the selected optimal path is the included angle in the similar pathθ sThe smallest one, rather than selecting one at will, so the best path is the one of the set of similar paths that most closely approximates the exact solution.
In a preferred embodiment of the invention, the test rayThe number of the test RAYs in the RAY set is more than 10000, and is in direct proportion to the calculation precision. In practice, according to the requirement of precision, a corresponding number of test RAY sets can be created, the test RAY sets are RAY = { r | r ∈ { point on unit sphere } }, the directions of the test RAYs point to the sphere from the center of the sphere, all the test RAYs are uniformly distributed on the sphere, and included angles among the test RAYs areθ ray ，θ ray Is determined by the number of testing rays, for example, when the number of testing rays is 10000-40000, that is
Between 2 and 1 degrees, the number of rays is typically greater than 10000 (C) ((R))θ ray <2 degrees) can meet the requirement, the specific number can be determined according to the actual requirement, the more the number of the test rays is, the higher the calculation precision is, according to the practice, generally speaking, the more than 3 thousands of the test rays can meet the general precision requirement, and for the scene with higher precision requirement, the number of the test rays can be properly increased. In addition, all the test RAYs can also be arranged unevenly on the spherical surface, that is, included angles between the test RAYs can be different, for example, the test RAYs pointing to the periphery (equatorial direction) of the spherical surface in the test RAY set RAY can be dense, while the test RAYs pointing to the upper and lower parts (north and south poles) of the spherical surface can be sparse, at this time,θ ray the value of (d) is the maximum included angle between adjacent test rays. Therefore, the calculation precision in the peripheral direction (equatorial direction) is enhanced, and the waste of calculation resources in the area with low occurrence probability of multipath is avoided. That is, the distribution density of the test RAYs in different areas in the test RAY set RAY is proportional to the occurrence probability of multipath in each area: in the area with high multipath occurrence probability, the number of the test rays is large, the distribution is dense, in the area with low multipath occurrence probability, the number of the test rays is small, the distribution is sparse, the waste of the calculation resources is avoided, and the reasonable distribution and optimization of the calculation resources are finally realized. As shown in FIG. 15, in the preferred embodiment of the present invention, after calculating the direct path and each diffraction path of the satellite signal to the receiver antenna and obtaining the set of diffraction multipath paths, steps are further includedThe method comprises the following steps:
s22, detecting the direct path shielding state between the satellite and the receiver antenna by using rays;
s23, detecting the occlusion state of each path in the diffraction multipath paths set DiffractPath by using rays, and discarding the occluded invalid path.
The embodiment detects the shielding state of a direct path and the shielding state of a diffraction multipath path through rays, and discards the shielded invalid path; in step S21, the diffraction paths are calculated in an unobstructed space, and all paths in the set of diffactpaths do not consider the occlusion of the static and dynamic grids, so this embodiment needs to eliminate the occluded diffraction multipath.
Specifically, in step S4, the power attenuation, time delay, and doppler data of each direct and multipath signal of the satellite arriving at the receiver antenna are calculated, which include:
calculating the distance attenuation of direct and multipath space transmission, and the reflection and transmission attenuation of multipath;
calculating a transmitting pitch angle and an azimuth angle of a satellite signal transmitting direction on a satellite antenna, and performing transmitting power attenuation calculation according to a directional diagram of the satellite antenna;
solving the pitch angle and azimuth angle of the signal incidence direction relative to the receiver antenna for the coordinates of the direct path and the multipath path, and carrying out receiving and transmitting power attenuation calculation according to the antenna directional diagram of the receiver;
calculating the space transmission time delay of direct and multipath, and the Doppler effect caused by the satellite speed and the receiver antenna speed;
calculating the diffraction attenuation of the diffraction multipath path according to the unified diffraction theory and the coordinates of the diffraction multipath path;
and calculating the power attenuation of the path in the whole transmission process according to the electromagnetic theory and the reflection coefficient/transmission coefficient of each reflection/transmission point of the reflection/transmission multi-path.
After the calculation, the power attenuation, the time delay and the Doppler data of the direct signal and the multipath path are sent to the navigation simulator, the direct signal power of the navigation simulator and the signal power, the time delay and the Doppler of the multipath channel are controlled, and the simulated navigation signal is generated.
Specifically, in the step S6, every 10 milliseconds of physical time elapses and the simulation time advances by 10 milliseconds, the steps S1 to S5 are repeatedly executed until the simulation is finished, so that the simulation computation speed meets the real-time calculation requirement of the update rate of 100Hz, and the update rate and the real-time performance during the navigation multi-path simulation are ensured.
Fig. 16 is a schematic diagram of multi-path simulation between a receiver antenna and a satellite obtained by the navigation multi-path real-time simulation method in the above embodiment, which includes a direct path, a blocked direct path, a diffraction multi-path, and a reflection/transmission multi-path, and truly embodies signal blocking and multi-path states of multiple receivers and multiple navigation satellites in a complex 3D scene, and solves the problems of high update rate and real-time performance.
As shown in fig. 17, a GPU-accelerated real environment navigation multipath real-time simulation apparatus according to a preferred embodiment of the present invention includes:
the scene updating module is used for updating the real-time scene of the 3D simulation scene of the real environment according to the simulated real-time dynamic parameters of the receiver carrier, the receiver antenna and the current simulation time of all the visible satellites;
the direct and diffraction calculation module is used for calculating direct paths and various diffraction paths of the satellite signals reaching the receiver antenna to obtain a diffraction multipath path set DiffractPath;
a RAY set tracking module for performing RAY tracking by using a preset test RAY set RAY to obtain a multi path set of reflection/transmission multi paths from all satellites to a receiver antenna at one time, wherein each test RAY in the test RAY set RAY is distributed on a unit spherical surface and points to the spherical surface by taking the position of the receiver antenna as the center of the sphere, and the maximum included angle between adjacent test RAYs isθ ray ；
The signal arrival parameter calculation module is used for calculating power attenuation, time delay and Doppler data of each direct and multipath signal of the satellite reaching the receiver antenna according to each path coordinate in the reflection/transmission multipath path set MultiPaths, each path coordinate in the diffraction multipath path set DiffractPaths, direct path coordinates, a signal transmission path, reflection/transmission coefficients of reflection points, satellite speed and receiver antenna speed, a satellite antenna directional diagram and a receiver antenna directional diagram;
the analog navigation signal generation module is used for generating direct and multipath analog navigation signals based on the current 3D simulation scene according to the power attenuation, the time delay and the Doppler data to perform multipath real-time simulation;
and the period advancing module is used for carrying out multi-path real-time simulation according to a set updating period until the simulation is finished.
In the real-environment navigation multipath real-time simulation device of the embodiment, the RAY set tracking module performs test RAY back tracking on the antenna of the receiver by using the unique test RAY set RAY, and all reflection/transmission multipath paths of the receiver and all satellites can be obtained by tracking once, so that the influence of the increase of the number of the satellites on the calculation time consumption is small, the time consumption is reduced to constant time from the multiple relation of the number of the satellites, the calculation amount is greatly reduced, the calculation time is ensured to be within 10 milliseconds each time, and the updating rate and the real-time performance of the navigation multipath simulation in the complex 3D scene of a plurality of receivers and a plurality of navigation satellites are improved.
Through practical verification, in the case of high load: in a complex scene with multiple satellites, multiple carriers, multiple antennas and millions of triangles, the signal calculation for simulating each satellite of each antenna for up to 32 paths of multipath and the reflection times for up to 6 times can be completed in real time. The operation speed of the simulation system reaches the real-time calculation requirement of 100Hz update rate.
The modules in the simulation device can be wholly or partially realized by software, hardware and a combination thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.
As shown in fig. 18, the preferred embodiment of the present invention further provides an electronic device, which includes a memory, a processor and a computer program stored in the memory and running on the processor, and when the processor executes the computer program, the real environment navigation multipath real-time simulation method in the above embodiments is implemented.
As shown in fig. 19, the preferred embodiment of the present invention also provides a computer device, which may be a terminal or a liveness detection server, and the internal structure thereof may be as shown in fig. 12. The computer device includes a processor, a memory, and a network interface connected by a system bus. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device comprises a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The network interface of the computer device is used for communicating with other external computer devices through network connection. The computer program is executed by a processor to realize the real environment navigation multipath real-time simulation method.
Those skilled in the art will appreciate that the configuration shown in fig. 19 is a block diagram of only a portion of the configuration associated with aspects of the present invention and is not intended to limit the computing devices to which aspects of the present invention may be applied, and that a particular computing device may include more or less components than those shown, or may combine certain components, or have a different arrangement of components.
As shown in fig. 20, in a preferred embodiment of the present invention, the real environment navigation multipath real-time simulation apparatus is in signal connection with the navigation simulator through the navigation simulator control module, the real environment navigation multipath real-time simulation apparatus of this embodiment obtains all visible satellite coordinates, speed and other parameters of the current simulation time from the navigation simulator, so that a network connection is established with the navigation simulator to realize command and data interaction during multipath real-time simulation, the navigation simulator provides satellite coordinates and speed for the multipath simulation apparatus, and the multipath simulation apparatus provides the navigation simulator with a receiver carrier, antenna motion trajectory data, satellite shielding information, multipath quantity, power attenuation, delay and doppler. The navigation simulator supported satellite system includes: the navigation simulator can create hardware signal generation channels with corresponding quantity according to the multipath quantity of each path of signal.
The preferred embodiment of the present invention further provides a storage medium, where the storage medium includes a stored program, and when the program runs, the storage medium controls a device on which the storage medium is located to execute the real environment navigation multipath real-time simulation method in the foregoing embodiments.
It should be noted that the steps illustrated in the flowcharts of the figures may be performed in a computer system such as a set of computer-executable instructions and that, although a logical order is illustrated in the flowcharts, in some cases, the steps illustrated or described may be performed in an order different than presented herein.
The functions of the method of the present embodiment, if implemented in the form of software functional units and sold or used as independent products, may be stored in one or more storage media readable by a computing device. Based on such understanding, part of the contribution of the embodiments of the present invention to the prior art or part of the technical solution may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computing device (which may be a personal computer, a server, a mobile computing device, a network device, or the like) to execute all or part of the steps of the method described in the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that are within the spirit and principle of the present invention are intended to be included in the scope of the present invention.
Claims (14)
1. A real environment navigation multipath real-time simulation method is characterized by comprising the following steps:
according to the simulated real-time dynamic parameters of the receiver carrier, the receiver antenna and all the visible satellites at the current simulation moment, carrying out real-time scene updating on the 3D simulation scene of the real environment;
calculating a direct path and each diffraction path of the satellite signal reaching the receiver antenna to obtain a diffraction multipath path set DiffractPaths;
performing RAY tracking by using a preset test RAY set RAY to obtain a multi path set of reflection/transmission multi paths from all satellites to a receiver antenna at one time, wherein all test RAYs in the test RAY set RAY are distributed on a unit spherical surface and point to the spherical surface by taking the position of the receiver antenna as the center of a sphere, and the maximum included angle between adjacent test RAYs is taken asθ ray ；
Calculating power attenuation, time delay and Doppler data of each direct and multipath signal of the satellite reaching the receiver antenna according to each path coordinate in a reflection/transmission multipath path set MultiPaths, each path coordinate in a diffraction multipath path set DiffractPaths, direct path coordinates, a signal transmission path, a reflection/transmission coefficient of a reflection point, satellite speed, receiver antenna speed, a satellite antenna directional diagram and a receiver antenna directional diagram;
generating direct and multipath simulated navigation signals based on the current 3D simulation scene according to the power attenuation, the time delay and the Doppler data to perform multipath real-time simulation;
and repeating the steps according to a set updating period until the simulation is finished.
2. The real environment navigation multipath real-time simulation method of claim 1,
before real-time scene updating is carried out on a 3D simulation scene of a real environment according to real-time dynamic parameters of a simulated receiver carrier, a receiver antenna and the current simulation time of all visible satellites, the method further comprises the following steps:
performing 3D modeling on a real environment, and expressing the real environment as triangular grid data in a set coordinate system, wherein the triangular grid data comprises a reflection coefficient, a transmission coefficient and an object ID;
dividing each triangular mesh into a static mesh and a dynamic mesh according to the position change condition in the simulation process and then respectively storing the static mesh and the dynamic mesh;
respectively establishing a static GPU ray detection acceleration structure and a dynamic GPU ray detection acceleration structure for the static grids and the dynamic grids;
and extracting static and dynamic diffraction edge data from the static grids and the dynamic grids respectively, and storing the data in a dynamic GPU diffraction edge storage area and a static GPU diffraction edge storage area respectively.
3. The real environment navigation multipath real-time simulation method of claim 2,
the method comprises the following steps of carrying out real-time scene updating on a 3D simulation scene of a real environment according to simulated real-time dynamic parameters of a receiver carrier, a receiver antenna and the current simulation time of all visible satellites, and specifically comprises the following steps:
setting a motion track of a simulated receiver carrier and configuration parameters of a receiver antenna, wherein the motion track comprises track, coordinates, postures and speed information of the receiver carrier, and the configuration parameters comprise relative position, posture, an antenna directional diagram and polarization mode information of the antenna on the receiver carrier;
acquiring coordinates and attitude information of a receiver carrier and a receiver antenna at the current moment according to the motion track of the receiver carrier, acquiring coordinates and speed of all visible satellites at the current simulation moment from a navigation simulator or a satellite operation simulation module, and converting coordinate data into a coordinate system corresponding to a triangular grid;
generating a transformation matrix through the coordinate and attitude information of a receiver carrier and a dynamic object, and applying the transformation matrix to carry out rotation and movement transformation on a dynamic grid and a dynamic diffraction edge so as to realize real-time scene updating of a 3D simulation scene;
and updating the transformed dynamic grid data and dynamic diffraction edge data to a dynamic GPU ray detection acceleration structure and a dynamic GPU diffraction edge storage area respectively.
4. The real environment navigation multipath real-time simulation method of claim 1,
calculating each diffraction path of the satellite signal reaching the receiver antenna to obtain a diffraction multipath path set DiffractPath, specifically comprising the following steps:
and traversing all static and dynamic diffraction edges in parallel, calculating diffraction points of each satellite signal reaching each receiver antenna through each diffraction edge according to a unified diffraction theory, and adding corresponding diffraction paths into a diffraction multipath path set DiffractPaths if the diffraction points exist.
5. The real environment navigation multipath real-time simulation method of claim 1,
the test RAYs in the test RAY set RAY are uniformly distributed on the spherical surface, and the included angles between adjacent test RAYs are equal to the maximum included angleθ ray The same;
or,
the distribution density of the test RAYs in different areas of the spherical surface in the test RAY set RAY is in direct proportion to the probability of the occurrence of the multipath in each area.
6. The real environment navigation multipath real-time simulation method of claim 1,
performing RAY tracking by using a preset test RAY set RAY, and acquiring a reflection/transmission multipath path set MultiPaths from all satellites to a receiver antenna at one time, wherein the method specifically comprises the following steps:
traversing the testing RAY set RAY in parallel, taking the receiver antenna as a starting point, taking the testing RAYs in the testing RAY set RAY as directions, tracking the reflection/transmission multipath paths when the RAYs pass through the triangular grid, and forming all potential reflection/transmission multipath path sets TracingPaths which reach the receiver antenna;
traversing paths in the set TracingPaths in parallel, and calculating the final reflection or transmission direction of the paths to be opposite to each satellite signalAngle of directionθ sIf, ifθ s ≤θ ray Then the path and the paired satellite are added to the set of reflected/transmitted multipath paths MultiPaths.
7. The real environment navigation multipath real-time simulation method of claim 6,
performing RAY tracking by using a preset test RAY set RAY, and acquiring a reflection/transmission multipath path set MultiPaths from all satellites to a receiver antenna at one time, wherein the method specifically comprises the following steps:
according to the geometrical optics principle, correcting coordinates of all paths in the set of MultiPaths on a triangular grid where reflection and transmission hit points are located are calculated in parallel, if the correcting coordinates fall into the corresponding reflection and transmission triangular grids, the paths are valid, the corrected coordinates are used for replacing the original coordinates of the reflection and transmission points, and if the correcting coordinates fall out of the corresponding reflection and transmission triangular grids, the paths are invalid, and the paths are discarded.
8. The real environment navigation multipath real-time simulation method of claim 7,
performing RAY tracking by using a preset test RAY set RAY, and acquiring a reflection/transmission multipath path set MultiPaths from all satellites to a receiver antenna at one time, wherein the method specifically comprises the following steps:
the paths in the corrected set of MultiPaths are path simplified to eliminate similar paths in the reflected/transmitted multipath paths between the same set of satellites and receiver antennas.
9. The real environment navigation multipath real-time simulation method of claim 8,
the path simplification of the paths in the corrected set MultiPaths is performed to eliminate similar paths in reflection/transmission multipath paths between the same group of satellites and receiver antennas, and the method specifically includes the following steps:
classifying the reflection/transmission multipath paths among the same group of satellites and receiver antennas in the corrected set MultiPaths, and if the paths have the same reflection/transmission structure and the difference of the path turning angles corresponding to the reflection/transmission points is smaller than a set threshold value, classifying the paths into the same class;
selecting angles among reflecting/transmitting multipath paths in the same classθ sThe smallest one is taken as the best path and the remaining paths are discarded.
10. The real environment navigation multipath real-time simulation method of claim 1,
the number of the test RAYs in the test RAY set RAY is more than 10000, and is in direct proportion to the calculation precision.
11. The real environment navigation multipath real-time simulation method of claim 1,
after the direct path and each diffraction path of the satellite signal reaching the receiver antenna are calculated to obtain a diffraction multipath path set DiffractPath, the method further comprises the following steps:
detecting a direct path shielding state between the satellite and the receiver antenna by using rays, and discarding a shielded invalid path;
the ray detection is used to detect the occlusion state of each path in the set of diffracted multipath paths diffactpaths, and the invalid paths occluded therein are discarded.
12. A real environment navigation multipath real-time simulation device is characterized by comprising:
the scene updating module is used for updating the real-time scene of the 3D simulation scene of the real environment according to the simulated real-time dynamic parameters of the receiver carrier, the receiver antenna and the current simulation time of all the visible satellites;
the direct and diffraction calculation module is used for calculating direct paths and various diffraction paths of the satellite signals reaching the receiver antenna to obtain a diffraction multipath path set DiffractPath;
a ray set tracking module for using preset test raysRAY tracking is carried out by a RAY set RAY, reflection/transmission multipath path sets MultiPaths from all satellites to a receiver antenna are obtained at one time, all testing RAYs in the testing RAY set RAY are distributed on a unit spherical surface and point to the spherical surface by taking the position of the receiver antenna as the center of a sphere, and the maximum included angle between adjacent testing RAYs isθ ray ；
The signal arrival parameter calculation module is used for calculating power attenuation, time delay and Doppler data of each direct and multipath signal of the satellite reaching the receiver antenna according to each path coordinate in the reflection/transmission multipath path set MultiPaths, each path coordinate in the diffraction multipath path set DiffractPaths, direct path coordinates, a signal transmission path, reflection/transmission coefficients of reflection points, satellite speed and receiver antenna speed, a satellite antenna directional diagram and a receiver antenna directional diagram;
the analog navigation signal generation module is used for generating direct and multipath analog navigation signals based on the current 3D simulation scene according to the power attenuation, the time delay and the Doppler data to perform multipath real-time simulation;
and the period advancing module is used for carrying out multi-path real-time simulation according to a set updating period until the simulation is finished.
13. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor,
the processor, when executing the program, implements the steps of the real environment navigation multipath real-time simulation method of any one of claims 1 to 11.
14. A storage medium including a stored program, characterized in that,
controlling a device on which the storage medium is located to perform the steps of the real environment navigation multipath real-time simulation method according to any one of claims 1 to 11 when the program is run.
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