A kalman filter-based pseudolite ephemeris parameter design method
By calculating ephemeris parameters using Kalman filtering technology, the problem of large position errors in pseudosatellite signal broadcasting was solved, enabling accurate prediction and positioning calculation of pseudosatellite positions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-30
- Publication Date
- 2026-03-31
AI Technical Summary
During pseudosatellite signal broadcasting, the dynamic changes of the pseudosatellite cause the ephemeris parameters to be unable to accurately characterize the motion of the pseudosatellite, resulting in a large position error.
A Kalman filtering-based method is employed to accurately characterize the motion characteristics of the pseudosatellite by calculating and fitting ephemeris parameters, including real-time position, standard cruise speed, and Kalman filtering of the difference, through signal interaction between the pseudosatellite transmitter and the user receiver.
It reduces pseudo-satellite position errors, enables accurate prediction of pseudo-satellite positions in dynamic environments, and improves the accuracy of positioning solutions.
Smart Images
Figure CN116027358B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of pseudosatellite technology, and in particular to a pseudosatellite ephemeris parameter design method based on Kalman filtering. Background Technology
[0002] With the development of pseudosatellite technology, when GNSS satellite signals cannot be received in an area due to co-channel interference, it is possible to consider using drones to carry pseudosatellites to establish a temporary spatial reference point over that area. Once the airborne pseudosatellite platform is established, it is necessary to broadcast pseudosatellite position information to ground users to ensure they can perform positioning calculations.
[0003] However, when using an airborne pseudo-satellite platform to broadcast signals to ground users, the pseudo-satellite's position is dynamic. Even when using a drone to carry the pseudo-satellite for signal broadcasting, the real-time position of the pseudo-satellite will have a certain error from the standard route due to wind, air resistance, etc., making it impossible for the fitted ephemeris parameters to accurately characterize the pseudo-satellite's motion. Summary of the Invention
[0004] Therefore, it is necessary to provide a pseudo-satellite ephemeris parameter design method based on Kalman filtering to address the aforementioned technical problems.
[0005] A pseudo-satellite ephemeris parameter design method based on Kalman filtering, the method comprising:
[0006] The pseudo-satellite transmitter acquires the real-time position of the pseudo-satellite, the pre-set standard cruise route, and the standard cruise speed of the pseudo-satellite on the standard cruise route;
[0007] The pseudo-satellite transmitter obtains the standard position of the pseudo-satellite based on the standard cruise route, calculates the difference between the real-time position and the standard position at the time of signal transmission to obtain a first difference, performs Kalman filtering on the first difference, fits the ephemeris parameters to obtain the ephemeris parameters, and broadcasts the ephemeris parameters to the user receiver through the pseudo-satellite signal; the ephemeris parameters include the first difference, the standard cruise speed, and the standard position.
[0008] The user receiver receives the pseudo-satellite signal, calculates the Kalman gain based on the ephemeris parameters in the pseudo-satellite signal, and calculates the second difference based on the Kalman gain and the first difference; the second difference is the predicted difference between the real-time position and the standard position of the pseudo-satellite at the time of signal reception.
[0009] The user receiver calculates the predicted position of the pseudo-satellite at the moment of signal reception based on the second difference, the standard position, and the standard cruise speed.
[0010] In one embodiment, the method further includes: calculating a second difference based on the Kalman gain and the first difference.
[0011]
[0012]
[0013]
[0014] Among them, t k t0 is the signal reception time, t0 is the signal transmission time, and T is the pseudo-satellite position sampling period. Let t0 be the difference between the real-time position and the standard position in the x-direction. This represents the difference in the y-direction between the real-time position and the standard position at time t0. Let be the difference between the real-time position and the standard position in the z-direction at time t0. For t k The predicted value of the difference between the real-time position and the standard position in the x-direction. For t k The predicted value of the difference between the real-time position and the standard position in the y-direction. For t k The predicted value of the difference between the real-time position and the standard position in the z-direction. The Kalman filter value on the X-axis at time t0 is... The Kalman filter value on the Y-axis at time t0 is... Let H(t) be the Kalman filter value on the Z-axis at time t0, H(·) be the observation matrix, and K(n) be the Kalman gain.
[0015] In one embodiment, the predicted position of the pseudo-satellite at the signal reception time is:
[0016]
[0017] in, This represents the predicted position of the pseudosatellite at the moment of signal reception. This is the standard position of the pseudosatellite at the moment of signal transmission. The standard cruising speed of a pseudosatellite at the moment of signal transmission. This is the second difference.
[0018] In one embodiment, the method further includes: calculating the Kalman gain based on the ephemeris parameters in the pseudo-satellite signal; the ephemeris parameters include the maneuver frequency of the pseudo-satellite motion model; the pseudo-satellite motion model includes the Singer motion model or the Jerk motion model.
[0019] In one embodiment, the method further includes: a user receiver receiving the pseudo-satellite signal and calculating the pseudo-satellite time based on the ephemeris parameters and the signal reception time.
[0020] In one embodiment, the method further includes: a user receiver receiving the pseudo-satellite signal, interpreting the ephemeris parameters in the pseudo-satellite signal to obtain clock bias parameters and signal transmission time; and the user receiver calculating the pseudo-satellite time based on the clock bias parameters, signal transmission time, and signal reception time.
[0021] In one embodiment, the pseudo-satellite time is further defined as:
[0022]
[0023] Among them, t tk For pseudosatellite time, t k The time of signal reception. Here, t is the clock difference parameter, and t0 is the signal transmission time.
[0024] In one embodiment, the method further includes: when the cruise standard route is a straight line, obtaining the standard position of the pseudo-satellite based on the projection of the pseudo-satellite onto the cruise standard route; when the cruise standard route is an arc, obtaining the standard position of the pseudo-satellite based on the intersection of the line connecting the center of the pseudo-satellite and the center of the cruise standard route on the cruise standard route.
[0025] In one embodiment, the ephemeris parameters within the pseudo-satellite signal are updated according to the ephemeris update cycle.
[0026] A pseudo-satellite ephemeris parameter design device based on Kalman filtering, the device comprising:
[0027] The motion parameter acquisition module is used by the pseudo-satellite transmitter to acquire the real-time position of the pseudo-satellite, the pre-set standard cruise route, and the standard cruise speed of the pseudo-satellite on the standard cruise route.
[0028] The ephemeris parameter design module is used by the pseudosatellite transmitter to obtain the standard position of the pseudosatellite based on the standard cruise route, calculate the difference between the real-time position and the standard position at the time of signal transmission to obtain a first difference, perform Kalman filtering on the first difference, fit to obtain ephemeris parameters, and broadcast the ephemeris parameters to the user receiver through the pseudosatellite signal; the ephemeris parameters include the first difference, the standard cruise speed, and the standard position.
[0029] The second difference calculation module is used for the user receiver to receive the pseudo-satellite signal, calculate the Kalman gain based on the ephemeris parameters in the pseudo-satellite signal, and calculate the second difference based on the Kalman gain and the first difference; the second difference is the predicted difference between the real-time position and the standard position of the pseudo-satellite at the time of signal reception.
[0030] The real-time position output module is used by the user receiver to calculate the predicted position of the pseudo-satellite at the time of signal reception based on the second difference, the standard position, and the standard cruise speed.
[0031] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program performing the following steps:
[0032] The pseudo-satellite transmitter acquires the real-time position of the pseudo-satellite, the pre-set standard cruise route, and the standard cruise speed of the pseudo-satellite on the standard cruise route;
[0033] The pseudo-satellite transmitter obtains the standard position of the pseudo-satellite based on the standard cruise route, calculates the difference between the real-time position and the standard position at the time of signal transmission to obtain a first difference, performs Kalman filtering on the first difference, fits the ephemeris parameters to obtain the ephemeris parameters, and broadcasts the ephemeris parameters to the user receiver through the pseudo-satellite signal; the ephemeris parameters include the first difference, the standard cruise speed, and the standard position.
[0034] The user receiver receives the pseudo-satellite signal, calculates the Kalman gain based on the ephemeris parameters in the pseudo-satellite signal, and calculates the second difference based on the Kalman gain and the first difference; the second difference is the predicted difference between the real-time position and the standard position of the pseudo-satellite at the time of signal reception.
[0035] The user receiver calculates the predicted position of the pseudo-satellite at the moment of signal reception based on the second difference, the standard position, and the standard cruise speed.
[0036] A computer-readable storage medium having a computer program stored thereon, the computer program performing the following steps when executed by a processor:
[0037] The pseudo-satellite transmitter acquires the real-time position of the pseudo-satellite, the pre-set standard cruise route, and the standard cruise speed of the pseudo-satellite on the standard cruise route;
[0038] The pseudo-satellite transmitter obtains the standard position of the pseudo-satellite based on the standard cruise route, calculates the difference between the real-time position and the standard position at the time of signal transmission to obtain a first difference, performs Kalman filtering on the first difference, fits the ephemeris parameters to obtain the ephemeris parameters, and broadcasts the ephemeris parameters to the user receiver through the pseudo-satellite signal; the ephemeris parameters include the first difference, the standard cruise speed, and the standard position.
[0039] The user receiver receives the pseudo-satellite signal, calculates the Kalman gain based on the ephemeris parameters in the pseudo-satellite signal, and calculates the second difference based on the Kalman gain and the first difference; the second difference is the predicted difference between the real-time position and the standard position of the pseudo-satellite at the time of signal reception.
[0040] The user receiver calculates the predicted position of the pseudo-satellite at the moment of signal reception based on the second difference, the standard position, and the standard cruise speed.
[0041] The aforementioned pseudo-satellite ephemeris parameter design method based on Kalman filtering obtains the real-time position of the pseudo-satellite and its standard position on the standard cruise route through a pseudo-satellite receiver. The difference between the real-time position and the standard position at the time of signal transmission is calculated to obtain a first difference. Kalman filtering is then applied to this first difference to fit and obtain ephemeris parameters. These parameters characterize the pseudo-satellite's motion characteristics and reduce position errors. The ephemeris parameters are then broadcast to the user receiver via the pseudo-satellite signal. The user receiver uses the ephemeris parameters to calculate the real-time position of the pseudo-satellite at the time of signal reception. Specifically, the user receiver uses the satellite motion characteristics characterized by the ephemeris parameters to calculate the difference between the real-time position and the standard position at the time of signal reception, obtaining a second difference. Based on the second difference, the standard position, and the standard cruise speed, the predicted position of the pseudo-satellite at the time of signal reception is calculated. This embodiment of the invention can accurately characterize the position of the pseudo-satellite even when there is a difference between the real-time position and the standard cruise route. Attached Figure Description
[0042] Figure 1 This is a flowchart illustrating a pseudo-satellite ephemeris parameter design method based on Kalman filtering in one embodiment.
[0043] Figure 2 This is a schematic diagram illustrating the difference between the real-time position and the standard cruise route of a drone during straight-line cruise in one embodiment.
[0044] Figure 3 This is a schematic diagram illustrating the difference between the real-time position and the standard cruise route of a drone during arc-shaped cruise in one embodiment.
[0045] Figure 4This is a structural block diagram of a pseudo-satellite ephemeris parameter design device based on Kalman filtering in one embodiment;
[0046] Figure 5 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation
[0047] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0048] In one embodiment, such as Figure 1 As shown, a pseudo-satellite ephemeris parameter design method based on Kalman filtering is provided, including the following steps:
[0049] Step 102: The pseudo-satellite transmitter acquires the real-time position of the pseudo-satellite, the pre-set standard cruise route, and the standard cruise speed of the pseudo-satellite on the standard cruise route.
[0050] The standard cruise speed on the standard cruise route refers to the speed at which a pseudosatellite cruises on the standard cruise route.
[0051] Step 104: The pseudo-satellite transmitter obtains the standard position of the pseudo-satellite according to the standard cruise route, calculates the difference between the real-time position and the standard position at the time of signal transmission, obtains the first difference, performs Kalman filtering on the first difference, fits to obtain the ephemeris parameters, and broadcasts the ephemeris parameters to the user receiver through the pseudo-satellite signal.
[0052] The ephemeris parameters include the first difference, standard cruise speed, and standard position. The standard position refers to the pseudosatellite position along the standard cruise route. Pseudosatellite motion models include the Singer motion model or the Jerk motion model. For example... Figure 2 The diagram shows the difference between the real-time position of the drone during straight-line cruising and the standard cruising route. Figure 2 In practice, the real-time position of a UAV carrying a pseudosatellite deviates from the standard cruise route by a certain margin. Therefore, to address this characteristic, the method of this invention applies a Kalman filter to this difference, thereby designing ephemeris parameters that accurately characterize the pseudosatellite's position. The Kalman filter algorithm iteratively runs time updates and observation updates sequentially to obtain parameter estimates for the current time at all epochs.
[0053] Step 106: The user receiver receives the pseudo-satellite signal, calculates the Kalman gain based on the ephemeris parameters in the pseudo-satellite signal, and calculates the second difference based on the Kalman gain and the first difference.
[0054] The second difference is the predicted difference between the real-time position and the standard position of the pseudo-satellite at the time of signal reception.
[0055] Step 108: The user receiver calculates the predicted position of the pseudo-satellite at the time of signal reception based on the second difference, the standard position, and the standard cruise speed.
[0056] The user receiver predicts the pseudosatellite position at the moment of signal reception based on the second difference and the standard position and standard cruise speed in the ephemeris parameters.
[0057] In the aforementioned pseudo-satellite ephemeris parameter design method based on Kalman filtering, the pseudo-satellite's real-time position and standard position on the standard cruise route are obtained through a pseudo-satellite receiver. The difference between the real-time position and the standard position at the time of signal transmission is calculated to obtain a first difference. Kalman filtering is then applied to this first difference to fit and obtain ephemeris parameters, which can characterize the pseudo-satellite's motion characteristics and reduce position errors. The ephemeris parameters are broadcast to the user receiver via the pseudo-satellite signal, allowing the user receiver to calculate the pseudo-satellite's real-time position at the time of signal reception. Specifically, the user receiver uses the satellite motion characteristics characterized by the ephemeris parameters to calculate the difference between the pseudo-satellite's real-time position and the standard position at the time of signal reception, obtaining a second difference. Based on the second difference, the standard position, and the standard cruise speed, the predicted position of the pseudo-satellite at the time of signal reception is calculated. This embodiment of the invention can accurately characterize the pseudo-satellite's position even when there is a difference between the pseudo-satellite's real-time position and the standard cruise route.
[0058] In one embodiment, calculating the second difference based on the Kalman gain and the first difference includes: calculating the second difference as follows:
[0059]
[0060]
[0061]
[0062] Among them, t k t0 is the signal reception time, t0 is the signal transmission time, and T is the pseudo-satellite position sampling period. Let t0 be the difference between the real-time position and the standard position in the x-direction. This represents the difference in the y-direction between the real-time position and the standard position at time t0. Let be the difference between the real-time position and the standard position in the z-direction at time t0. For t k The predicted value of the difference between the real-time position and the standard position in the x-direction. For t kThe predicted value of the difference between the real-time position and the standard position in the y-direction. For t k The predicted value of the difference between the real-time position and the standard position in the z-direction. The Kalman filter value on the X-axis at time t0 is... The Kalman filter value on the Y-axis at time t0 is... Let H(t) be the Kalman filter value on the Z-axis at time t0, H(·) be the observation matrix, and K(n) be the Kalman gain.
[0063] In one embodiment, the predicted position of the pseudo-satellite at the time of signal reception is:
[0064]
[0065] in, This represents the predicted position of the pseudosatellite at the moment of signal reception. This is the standard position of the pseudosatellite at the moment of signal transmission. The standard cruising speed of a pseudosatellite at the moment of signal transmission. This is the second difference.
[0066] In one embodiment, calculating the Kalman gain based on ephemeris parameters in the pseudosatellite signal includes: calculating the Kalman gain based on ephemeris parameters in the pseudosatellite signal; the ephemeris parameters include the maneuver frequency of the pseudosatellite motion model; the pseudosatellite motion model includes the Singer motion model or the Jerk motion model. In this embodiment, based on the received parameters n and σ... P α, σ w σ R Given T, calculate the Kalman gain, where n is the number of filters used in calculating the Kalman gain, and σ... P It is the initial value of the covariance matrix filtering, σ w It is system noise, σ R α represents the observation noise, and α represents the maneuver frequency of the Singer motion model and the Jerk motion model.
[0067] In one embodiment, the method further includes: a user receiver receiving a pseudo-satellite signal and calculating the pseudo-satellite time based on ephemeris parameters and the signal reception time.
[0068] In one embodiment, the step of a user receiver receiving a pseudo-satellite signal and calculating the signal reception time based on ephemeris parameters and signal reception time includes: the user receiver receiving the pseudo-satellite signal, interpreting the ephemeris parameters in the pseudo-satellite signal to obtain clock bias parameters and signal transmission time; and the user receiver calculating the pseudo-satellite time based on the clock bias parameters, signal transmission time, and signal reception time.
[0069] In one embodiment, the pseudo-satellite time is:
[0070]
[0071] Among them, t tk For pseudosatellite time, t k The time of signal reception. Here, t is the clock difference parameter, and t0 is the signal transmission time.
[0072] In one embodiment, the step of obtaining the standard position of a pseudosatellite based on a pre-set cruise standard route includes: when the cruise standard route is a straight line, obtaining the standard position of the pseudosatellite based on its projection onto the cruise standard route; when the cruise standard route is an arc, obtaining the standard position of the pseudosatellite based on the intersection of the line connecting the center of the pseudosatellite and the center of the cruise standard route on the cruise standard route. In this embodiment, as... Figure 2 The diagram shows the difference between the real-time position of the drone during straight-line cruise and the standard cruise route. The dashed line represents the standard cruise route, in which case the drone is performing straight-line cruise. The solid line represents the standard position on the standard cruise route, while the real-time cruise route is represented by the solid line. For real-time position, the difference during straight-line cruise is the difference between the drone's real-time position and its projection onto a standard route, such as... Figure 3 The diagram shows the difference between the real-time position of the drone and the standard cruise route during arc-shaped cruise. The dashed line represents the standard cruise route. At this time, the drone is performing arc-shaped cruise. The solid line represents the standard position on the standard cruise route, while the real-time cruise route is represented by the solid line. For real-time position, the difference during arc cruise is the difference between the drone's real-time position and the point on the standard route circle where the line connecting the drone and the center of the circle intersects.
[0073] In one embodiment, the ephemeris parameters within the pseudosatellite signal are updated with an ephemeris update cycle. In this embodiment, the ephemeris update cycle is denoted by T. up This indicates that the method of the present invention can accurately characterize the position of pseudo-satellites within the ephemeris update cycle.
[0074] In one specific embodiment, the difference between the received real-time position of the pseudo-satellite and the standard route of the UAV cruise is calculated. Kalman filtering is applied to the calculated difference to fit the ephemeris parameters. The ephemeris parameters of the pseudo-satellite are designed as follows:
[0075]
[0076]
[0077] Broadcast the pseudosatellite ephemeris parameters as shown in the table above, with a period of T. upThe ephemeris parameters are updated, and users calculate the pseudosatellite position and time based on the broadcast parameters.
[0078] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.
[0079] In one embodiment, such as Figure 4 As shown, a pseudo-satellite ephemeris parameter design device based on Kalman filtering is provided, including: a motion parameter acquisition module 402, an ephemeris parameter design module 404, a second difference calculation module 406, and a real-time position output module 408, wherein:
[0080] The motion parameter acquisition module 402 is used by the pseudo-satellite transmitter to acquire the real-time position of the pseudo-satellite, the pre-set cruise standard route, and the standard cruise speed of the pseudo-satellite on the cruise standard route.
[0081] The ephemeris parameter design module 404 is used by the pseudo-satellite transmitter to obtain the standard position of the pseudo-satellite according to the standard cruise route, calculate the difference between the real-time position and the standard position at the time of signal transmission, obtain the first difference, perform Kalman filtering on the first difference, fit to obtain the ephemeris parameters, and broadcast the ephemeris parameters to the user receiver through the pseudo-satellite signal; the ephemeris parameters include the first difference, the standard cruise speed, and the standard position.
[0082] The second difference calculation module 406 is used by the user receiver to receive pseudo-satellite signals, calculate the Kalman gain based on the ephemeris parameters in the pseudo-satellite signals, and calculate the second difference based on the Kalman gain and the first difference; the second difference is the predicted difference between the real-time position and the standard position of the pseudo-satellite at the time of signal reception.
[0083] The real-time position output module 408 is used by the user receiver to calculate the predicted position of the pseudo-satellite at the time of signal reception based on the second difference, the standard position, and the standard cruise speed.
[0084] In one embodiment, the second difference calculation module 406 is further configured to calculate the second difference as follows based on the Kalman gain and the first difference:
[0085]
[0086]
[0087]
[0088] Among them, t k t0 is the signal reception time, t0 is the signal transmission time, and T is the pseudo-satellite position sampling period. Let t0 be the difference between the real-time position and the standard position in the x-direction. This represents the difference in the y-direction between the real-time position and the standard position at time t0. Let be the difference between the real-time position and the standard position in the z-direction at time t0. For t k The predicted value of the difference between the real-time position and the standard position in the x-direction. For t k The predicted value of the difference between the real-time position and the standard position in the y-direction. For t k The predicted value of the difference between the real-time position and the standard position in the z-direction. The Kalman filter value on the X-axis at time t0 is... The Kalman filter value on the Y-axis at time t0 is... Let H(t) be the Kalman filter value on the Z-axis at time t0, H(·) be the observation matrix, and K(n) be the Kalman gain.
[0089] In one embodiment, the real-time position output module 408 is further configured to predict the position of the pseudo-satellite at the time of signal reception as follows:
[0090]
[0091] in, This represents the predicted position of the pseudosatellite at the moment of signal reception. This is the standard position of the pseudosatellite at the moment of signal transmission. The standard cruising speed of a pseudosatellite at the moment of signal transmission. This is the second difference.
[0092] In one embodiment, the second difference calculation module 406 is further configured to calculate the Kalman gain based on the ephemeris parameters in the pseudo-satellite signal; the ephemeris parameters include the maneuver frequency of the pseudo-satellite motion model; the pseudo-satellite motion model includes the Singer motion model or the Jerk motion model.
[0093] In one embodiment, the user receiver also receives pseudo-satellite signals and calculates the pseudo-satellite time based on ephemeris parameters and signal reception time.
[0094] In one embodiment, the user receiver also receives the pseudo-satellite signal, decodes the ephemeris parameters in the pseudo-satellite signal, and obtains the clock difference parameters and the signal transmission time; the user receiver calculates the pseudo-satellite time based on the clock difference parameters, the signal transmission time, and the signal reception time.
[0095] In one embodiment, the pseudo-satellite time is also used as:
[0096]
[0097] Among them, t tk For pseudosatellite time, t k The time of signal reception. Here, t is the clock difference parameter, and t0 is the signal transmission time.
[0098] In one embodiment, the ephemeris parameter design module 404 is further configured to obtain the standard position of the pseudo-satellite based on the projection of the pseudo-satellite onto the cruise standard route when the cruise standard route is a straight line; and to obtain the standard position of the pseudo-satellite based on the intersection of the line connecting the center of the pseudo-satellite and the center of the cruise standard route on the cruise standard route when the cruise standard route is an arc.
[0099] In one embodiment, the ephemeris parameter design module 404 is also used to update the ephemeris parameters in the pseudosatellite signal according to the ephemeris update cycle.
[0100] Specific limitations regarding the Kalman filter-based pseudo-satellite ephemeris parameter design device can be found in the limitations of the Kalman filter-based pseudo-satellite ephemeris parameter design method described above, and will not be repeated here. Each module in the aforementioned Kalman filter-based pseudo-satellite ephemeris parameter design device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the computer device's memory as software, so that the processor can call and execute the corresponding operations of each module.
[0101] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 5As shown, the computer device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The network interface is used for communication with external terminals via a network connection. When executed by the processor, the computer program implements a pseudo-satellite ephemeris parameter design method based on Kalman filtering. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.
[0102] Those skilled in the art will understand that Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.
[0103] In one embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of the method described above.
[0104] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described above.
[0105] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.
[0106] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0107] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A Kalman filter based pseudolite ephemeris parameter design method, characterized in that, The method comprises: The pseudo-satellite transmitter obtains a real-time position of the pseudo-satellite, a pre-set cruise standard route and a standard cruise speed of the pseudo-satellite on the cruise standard route; The pseudo-satellite transmitter obtains a standard position of the pseudo-satellite according to the cruise standard route, calculates a difference between the real-time position and the standard position at a signal transmission time to obtain a first difference, performs Kalman filtering on the first difference, and fits to obtain ephemeris parameters, which are broadcast to a user receiver through a pseudo-satellite signal; the ephemeris parameters comprise the first difference, the standard cruise speed and the standard position; The user receiver receives the pseudo-satellite signal, calculates a Kalman gain according to the ephemeris parameters in the pseudo-satellite signal, and calculates a second difference according to the Kalman gain and the first difference; the second difference is a predicted value of a difference between a real-time position and a standard position of the pseudo-satellite at a signal receiving time; The user receiver calculates a predicted position of the pseudo-satellite at the signal receiving time according to the second difference, the standard position and the standard cruise speed.
2. The method of claim 1, wherein, The calculating of the second difference according to the Kalman gain and the first difference comprises: The calculating of the second difference according to the Kalman gain and the first difference is: wherein, is a signal receiving time, is a signal transmitting time, is a pseudo-satellite position sampling period, is a difference between a real-time position and a standard position in direction at a time, is a difference between a real-time position and a standard position in direction at a time, is a difference between a real-time position and a standard position in direction at a time, is a difference between a real-time position and a standard position in direction at a time, is a difference between a real-time position and a standard position in direction at a time, is a difference between a real-time position and a standard position in direction at a time, is a Kalman filter value in axis at a time, is a Kalman filter value in axis at a time, is a Kalman filter value in axis at a time, is an observation matrix, is a Kalman gain.
3. The method of claim 1, wherein, The predicted position of the pseudo-satellite at the signal receiving time is: wherein is a predicted position of the pseudolite at the signal reception time instant, is a standard position of the pseudolite at the signal transmission time instant, is a standard cruising speed of the pseudolite at the signal transmission time instant, is a second difference.
4. The method of claim 1, wherein, The calculating of the Kalman gain according to the ephemeris parameters in the pseudo-satellite signal comprises: The Kalman gain is calculated according to the ephemeris parameters in the pseudo-satellite signal; the ephemeris parameters comprise a maneuvering frequency of a pseudo-satellite motion model; the pseudo-satellite motion model comprises a Singer motion model or a Jerk motion model.
5. The method of claim 1, wherein, The method further comprises: The user receiver receives the pseudo-satellite signal, and calculates a pseudo-satellite time according to the ephemeris parameters and a signal receiving time.
6. The method of claim 5, wherein, The step of calculating the signal receiving time according to the ephemeris parameters and a signal receiving time by the user receiver receiving the pseudo-satellite signal comprises: The user receiver receives the pseudo-satellite signal, and obtains a clock difference parameter and a signal transmission time by interpreting the ephemeris parameters in the pseudo-satellite signal; The user receiver calculates the pseudo-satellite time according to the clock difference parameter, the signal transmission time and the signal receiving time.
7. The method of claim 6, wherein, The pseudo-satellite time is: wherein is a pseudo satellite time, is a signal reception time instant, , is a clock bias parameter, is a signal transmission time instant.
8. The method of claim 1, wherein, The step of obtaining the standard position of the pseudo-satellite according to the cruise standard route comprises: When the cruise standard route is a straight line, the standard position of the pseudo-satellite is obtained according to a projection of the pseudo-satellite on the cruise standard route; When the cruise standard route is an arc, the standard position of the pseudo-satellite is obtained according to an intersection point of a line between the pseudo-satellite and a center of the cruise standard route on the cruise standard route.
9. The method of claim 1, wherein, The ephemeris parameters in the pseudo-satellite signal are updated at an ephemeris update period.
10. A Kalman filter based pseudolite ephemeris parameter design apparatus, characterized by, The device comprises: a motion parameter obtaining module configured to enable a pseudo-satellite transmitter to obtain a real-time position of the pseudo-satellite, a pre-set cruise standard route and a standard cruise speed of the pseudo-satellite on the cruise standard route; The ephemeris parameter design module is configured to obtain a standard position of the pseudolite according to the standard cruise route, calculate a difference between the real-time position and the standard position at the signal transmission time, obtain a first difference value, perform Kalman filtering on the first difference value, and fit to obtain ephemeris parameters. The ephemeris parameters are broadcast to the user receiver through the pseudolite signal. The ephemeris parameters include the first difference value, the standard cruise speed, and the standard position. The second difference value calculation module is configured to receive the pseudolite signal by the user receiver, calculate a Kalman gain according to the ephemeris parameters in the pseudolite signal, and calculate a second difference value according to the Kalman gain and the first difference value. The second difference value is a predicted value of the difference between the real-time position and the standard position of the pseudolite at the signal receiving time. The real-time position output module is configured to calculate a predicted position of the pseudolite at the signal receiving time according to the second difference value, the standard position, and the standard cruise speed.