Method and device for determining satellite clock error

Abstract

An embodiment of the present invention provides a method and device for determining satellite clock error, including: a first satellite receives precise ephemeris and first observation data from a second satellite, wherein the operating orbit of the second satellite is higher than that of the first satellite, the first satellite is located outside the target area at the target time, and the first observation data is data obtained at the target time; the first satellite obtains a target time difference through the target time and a reference time, and determines a delay estimation value according to the target time difference, wherein the reference time is the time when the first satellite last entered the target area; the first satellite determines the first satellite clock error of the first satellite through the delay estimation value, the precise ephemeris, and the first observation data. Through the present invention, the problem in the related art that the satellite clock error cannot be directly extracted based on monitoring data is solved, and the effect of precisely generating the satellite clock error of a low-orbit satellite is achieved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of communications, and in particular, to a method and apparatus for determining satellite clock error. Background Art

[0002] The integrated solution of low-earth orbit navigation satellites and medium-high earth orbit navigation satellites can achieve global rapid precise positioning. The satellite clock error of low-earth orbit navigation satellites that can broadcast precise downlink signals globally is one of the important prerequisites for global rapid precise positioning. However, in practical applications, since ground monitoring devices cannot be widely deployed globally, it is impossible to directly extract satellite clock error based on the monitoring data of navigation satellite downlink signals, resulting in the difficulty of realizing global rapid precise positioning services.

[0003] In view of the above problems, there is currently no effective solution. Summary of the Invention

[0004] The embodiments of the present invention provide a method and apparatus for determining satellite clock error, so as to at least solve the problem in the related art that satellite clock error cannot be directly extracted based on monitoring data.

[0005] According to an embodiment of the present invention, a method for determining satellite clock error is provided, including: a first satellite receives a precise ephemeris and first observation data from a second satellite, where the orbit of the second satellite is higher than that of the first satellite, the first satellite is located outside the target area at the target time, and the first observation data is the data obtained at the target time; the first satellite obtains a target time difference through the target time and the reference time, and determines a time delay estimation value according to the target time difference, where the reference time is the time when the first satellite last entered the target area; the first satellite determines the first satellite clock error of the first satellite through the time delay estimation value, the precise ephemeris, and the first observation data.

[0006] In an exemplary embodiment, the first satellite determines the first satellite clock error of the first satellite through the time delay estimation value, the precise ephemeris, and the first observation data, including: the first satellite determines the first receiver clock error of the first satellite according to the precise ephemeris and the first observation data; the first satellite determines the difference between the first receiver clock error and the time delay estimation value as the first satellite clock error of the downlink signal of the first satellite.

[0007] In an exemplary embodiment, the first satellite determines a first receiver clock offset of the first satellite based on precise ephemeris and first observation data, including: the first satellite obtains a target position of a second satellite and a second satellite clock offset of the second satellite from the precise ephemeris, where the position of the second satellite at the target time is the target position; the first satellite obtains a first pseudorange and a first carrier phase between the first satellite and the second satellite from the first observation data; the first satellite determines a first position of the first satellite at a first time based on the target position of the second satellite, the second satellite clock offset, the first pseudorange, and the first carrier phase, where the first time is after the target time; the first satellite determines the first receiver clock offset of the first satellite based on the target position of the second satellite, the first position, the second satellite clock offset, the first pseudorange, and the first carrier phase.

[0008] In an exemplary embodiment, determining the delay estimation value according to the target time difference includes: the first satellite obtains a delay function from a ground data processing center, where the delay function is obtained by fitting the delay of the transceiver channel of the first satellite by the ground data processing center; the first satellite determines the delay estimation value according to the target time difference and the delay function.

[0009] In an exemplary embodiment, the above method further includes: the ground data processing center obtains the delay function by the following method: the ground data processing center determines the delays of the transceiver channel of the first satellite at multiple time points to obtain a delay set, where the multiple time points are before the target time; the ground data processing center fits each delay in the delay set through the multiple time points to obtain the delay function.

[0010] In an exemplary embodiment, the ground data processing center determines the delays of the transceiver channel of the first satellite at multiple time points, including: the ground data processing center determines the delay of the transceiver channel of the first satellite at the k-th time point by the following method, where k is an integer and the k-th time point is any one of the multiple time points: the ground data processing center determines a second receiver clock offset of the first satellite at the k-th time point; the ground data processing center determines a third satellite clock offset of the first satellite at the k-th time point; the ground data processing center determines the difference between the second receiver clock offset and the third satellite clock offset of the first satellite as the delay of the transceiver channel of the first satellite at the k-th time point.

[0011] In an exemplary embodiment, the ground data processing center determines the third satellite clock error of the first satellite at the k-th time point, including: the ground data processing center obtains the second pseudo-range and the second carrier phase between the first satellite and the ground navigation terminal in the second observation data, where the second observation data is the data obtained at the k-th time point; the ground data processing center determines the second position of the first satellite at the second moment, where the second moment is the moment after the k-th time point; and determines the third satellite clock error according to the second pseudo-range, the second carrier phase and the second position.

[0012] In an exemplary embodiment, the first satellite and the second satellite belong to navigation satellites.

[0013] According to another embodiment of the present invention, there is provided an apparatus for determining satellite clock error, which is applied to the above-mentioned first satellite, including: a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the following operations are implemented: receiving precise ephemeris and first observation data from the second satellite, where the operating orbit of the second satellite is higher than that of the first satellite, the first satellite is located outside the target area at the target moment, and the first observation data is the data obtained at the target moment; obtaining a target time difference through the target moment and the reference moment, and determining a time delay estimation value according to the target time difference, where the reference moment is the moment when the first satellite last entered the target area; and determining the first satellite clock error of the first satellite through the time delay estimation value, the precise ephemeris, and the first observation data.

[0014] According to still another embodiment of the present invention, there is also provided a computer-readable storage medium, in which a computer program is stored, and when the computer program is executed by a processor, the steps in any one of the above method embodiments are implemented.

[0015] According to still another embodiment of the present invention, there is also provided an electronic device, including a memory and a processor, where a computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0016] According to still another embodiment of the present invention, there is also provided a computer program product, including a computer program, and when the computer program is executed by a processor, the steps in any one of the above method embodiments are implemented.

[0017] Through the present invention, when the first satellite runs outside the target area, the first satellite receives precise ephemeris and first observation data from the second satellite at the target moment. At the same time, the first satellite determines the time delay estimation value of the first satellite at the target moment based on the target time difference between the target moment and the reference moment, and determines the first satellite clock error of the first satellite according to the precise ephemeris, the first observation data, and the time delay estimation value.

[0018] By simulating the time delay of the transceiver channels of the first satellite at the target moment and accurately generating the satellite clock error of the downlink signal based on the time delay of the transceiver channels, it effectively avoids the problem that due to the inability to deploy ground monitoring equipment outside the target area, the time delay of the transceiver channels of low-earth orbit navigation satellites cannot be obtained through monitoring data, resulting in the inability to generate the satellite clock error of the downlink signal. Therefore, it can solve the problem in the related technology that the satellite clock error cannot be directly extracted based on the monitoring data, and achieve the effect of precisely generating the satellite clock error of low-earth orbit satellites. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the application scenario of the method for determining the satellite clock error according to an embodiment of the present invention;

[0020] Figure 2 is a hardware structure block diagram of a mobile terminal of a method for determining the satellite clock error according to an embodiment of the present invention;

[0021] Figure 3 is a flowchart of the method for determining the satellite clock error according to an embodiment of the present invention;

[0022] Figure 4 is a schematic flowchart of generating the satellite clock error of the downlink signal of a low-earth orbit navigation satellite according to an embodiment of the present invention;

[0023] Figure 5 is a structure block diagram of the device for determining the satellite clock error according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The embodiments of the present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence.

[0026] Figure 1 is a schematic diagram of the application scenario of the method for determining the satellite clock error according to an embodiment of the present invention. As Figure 1 shown, this scenario includes a global positioning system, low-earth orbit satellites, ground navigation terminals, ground injection stations, and ground data processing centers, where:

[0027] The global positioning system is a technical system that provides global positioning, navigation, and timing services through a group of satellites, and can provide high-precision positioning, navigation, and timing services for global users.

[0028] Low-earth orbit satellites refer to satellites operating in low-earth orbits, which are mainly responsible for providing radio communication services, data transmission, positioning, and navigation, etc.

[0029] The ground navigation terminal is a user receiving device composed of a receiver, a timer, a data pre-processor, a computer, a display, etc. It can receive radio navigation signals sent by navigation satellites, obtain navigation parameters such as the distance or the rate of change of distance between the user and the satellite through time ranging or Doppler velocity measurement, and calculate the geographical position coordinates (two-dimensional or three-dimensional coordinates) and velocity vector components of the user according to the time and orbital parameters sent by the satellite.

[0030] The ground injection station is an important part of the satellite navigation system, mainly responsible for injecting navigation messages and control instructions into the navigation satellites in orbit. The injection station injects satellite ephemeris, clock bias, navigation messages and other control instructions calculated and compiled by the master control station into the data memory of the satellite at a high transmission rate through radio equipment, and monitors the correctness of the injected information.

[0031] The ground data processing center is the center for ground information processing and operation control of the navigation satellite system. Its main tasks are to collect satellite signals, observation data and environmental data collected by each monitoring station, perform time synchronization and satellite clock bias prediction, precise satellite orbit determination and ephemeris parameter generation, wide-area differential correction value calculation, ionospheric model parameter calculation, and system integrity calculation, etc., and realize the mission planning and scheduling of the navigation satellite system, the operation management and control of the whole system, etc.

[0032] Through the above devices and the information interaction between the devices, the fusion calculation of low-earth orbit navigation satellites and medium-high-earth orbit navigation satellites can be carried out, so as to realize global fast and precise positioning.

[0033] In the method embodiments provided in the embodiments of the present application, the on-board receiver on the satellite, the ground data processing center, and the ground navigation terminal in the method embodiments can be executed in a mobile terminal, a computer terminal or a similar computing device. Taking running on a computing device as an example, Figure 2 is the hardware structure block diagram of a mobile terminal of a method for determining satellite clock bias according to an embodiment of the present invention. As Figure 2 shown, the mobile terminal may include one or more ( Figure 2 only one is shown in Figure 2 processors 102 (the processor 102 may include, but is not limited to, a processing device such as a microprocessor MCU or a programmable logic device FPGA) and a memory 104 for storing data. Among them, the above mobile terminal may further include a transmission device 106 for communication functions and an input / output device 108. Those of ordinary skill in the art can understand that Figure 2 the structure shown is only schematic, and it does not limit the structure of the above mobile terminal. For example, the mobile terminal may further include more or fewer components than Figure 2 shown, or have a different configuration from Figure 2 shown.

[0034] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the method for determining satellite clock error in the embodiments of the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, implements the above-mentioned method. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memories. In some instances, the memory 104 may further include a memory remotely disposed relative to the processor 102, and these remote memories can be connected to the mobile terminal through a network. Examples of the above-mentioned network include but are not limited to the Internet, intranet, local area network, mobile communication network, and combinations thereof.

[0035] The transmission device 106 is used to receive or send data via a network. Specific examples of the above-mentioned network may include a wireless network provided by a communication provider of the mobile terminal. In one instance, the transmission device 106 includes a network adapter (Network Interface Controller, abbreviated as NIC), which can be connected to other network devices through a base station and thus communicate with the Internet. In one instance, the transmission device 106 can be a radio frequency (Radio Frequency, abbreviated as RF) module, which is used to communicate with the Internet wirelessly.

[0036] In this embodiment, a method running on the above-mentioned mobile terminal or network architecture is provided. Figure 3 It is a flowchart of the method for determining satellite clock error according to the embodiments of the present invention, as Figure 3 shown, and the process includes the following steps:

[0037] Step S302, the first satellite receives precise ephemeris and first observation data from the second satellite, wherein the operating orbit of the second satellite is higher than that of the first satellite, the first satellite is located outside the target area at the target moment, and the first observation data is the data obtained at the target moment;

[0038] The above-mentioned first satellite can be a low-earth orbit satellite (or a low-earth orbit navigation satellite), etc. This navigation satellite operates in a low-earth orbit and is used to provide precise global positioning and navigation services. Among them, compared with traditional medium-high earth orbit navigation satellites, low-earth orbit navigation satellites have a lower orbit altitude and a faster running speed, and can provide faster and more accurate navigation services; the above-mentioned second satellite can be a GNSS (Global Navigation Satellite System) satellite, that is, a medium-high earth orbit navigation satellite. This navigation satellite is usually in an earth-pass or perigee altitude orbit. Among them, compared with low-earth orbit navigation satellites, GNSS satellites have a higher orbit altitude, can provide a wider coverage area and more stable signal transmission, and thus provide more stable and accurate navigation services. Common GNSS satellites include GPS (Global Positioning System), GLONASS (Global Navigation Satellite System), Galileo (Galileo Satellite Navigation System), and BDS (BeiDou Navigation Satellite System), etc.

[0039] The above-mentioned precise message can be information with high confidentiality and accuracy transmitted by satellite. This precise message includes the precise satellite orbit, precise satellite clock error, and code deviation of the second satellite at the target moment, etc.; the above-mentioned first observation data can be the observation data of the on-board receiver of the second satellite at the target moment. This data is usually signal data from other satellites, including the position, speed, attitude, dual-frequency pseudorange, carrier phase, and other relevant information of the satellite, etc.; the above-mentioned target area can be an area where ground monitoring equipment is installed. This ground monitoring equipment can be a ground navigation terminal, a ground injection station, etc. Through the ground monitoring equipment, the ground data processing center can obtain the precise message of the satellite and the observation data of the on-board receiver; the above-mentioned target moment can be any moment when the first satellite is outside the target area. At the target moment, the first satellite can receive the precise message and the first observation data of the second satellite at the target moment.

[0040] When the low-earth orbit navigation satellite (i.e., the first satellite) is outside the target area, the low-earth orbit navigation satellite (i.e., the first satellite) receives the precise message of the GNSS satellite (i.e., the second satellite) and the observation data of the on-board receiver (i.e., the first observation data) at the target moment. For example, at the target moment, the first satellite runs to a certain position outside the target area A, and at this time, it receives the precise message and the first observation data from the second satellite.

[0041] Step S304: The first satellite obtains the target time difference based on the target moment and the reference moment, and determines the time delay estimation value according to the target time difference, where the reference moment is the moment when the first satellite last entered the target area;

[0042] The above-mentioned target moment can be any moment when the first satellite is outside the target area. At the target moment, the first satellite can receive the precise message and the first observation data of the second satellite at the target moment; the above-mentioned reference moment can be the reference moment for calculating the time difference, and this reference moment can be the moment when the first satellite last entered the target area; the above-mentioned time delay estimation value can be the time delay on the transceiver channel of the first satellite at the target moment obtained by fitting the first satellite.

[0043] The first satellite determines the difference between the target moment and the reference moment as the target time difference, and determines the time delay estimation value according to the target time difference, that is, the time delay of the transceiver channel of the first satellite at the target moment. For example, it takes 120 minutes for the first satellite to orbit once, among which, it operates within the target area A from 0 to 30 minutes and outside the target area A from 31 to 120 minutes. Then the target moment t can be any moment within 31 - 120 minutes, and the reference moment t0 can be the moment when the first satellite enters the target area A, that is, the 0 moment. Determine t - t0 as the target time difference, and determine the time delay estimation value according to the target time difference, that is, the time delay of the transceiver channel of the first satellite at the target moment t.

[0044] Step S306: The first satellite determines the first satellite clock error of the first satellite based on the time delay estimation value, the precise message, and the first observation data.

[0045] The above-mentioned first satellite clock error can be the satellite clock error of the downlink signal of the first satellite at the target moment, that is, the satellite clock error of the downlink signal when the first satellite operates outside the target area; through the time delay of the transceiver channel of the first satellite at the target moment (i.e., the time delay estimation value), the precise message received by the first satellite from the second satellite at the target moment, and the first observation data, the satellite clock error of the downlink signal of the first satellite at the target moment (i.e., the first satellite clock error) can be obtained, so that the precise generation of the satellite clock error of the downlink signal of the low-orbit navigation satellite can be realized in the area where ground monitoring equipment cannot be deployed.

[0046] As an optional implementation manner, the first satellite determines the first satellite clock error of the first satellite based on the time delay estimation value, the precise message, and the first observation data, including: the first satellite determines the first receiver clock error of the first satellite according to the precise message and the first observation data; the first satellite determines the difference between the first receiver clock error and the time delay estimation value as the first satellite clock error of the downlink signal of the first satellite.

[0047] The above-mentioned first receiver clock error may be the receiver clock error of the on-board receiver of the first satellite at the target time. This receiver clock error may be the time difference between the internal clock of the on-board receiver and the navigation signal transmitted by the satellite. The satellite clock error of the downlink signal of the satellite can be determined through the on-board receiver clock error of the satellite; the first satellite determines the receiver clock error (i.e., the first receiver clock error) of the on-board receiver of the first satellite at the target time according to the precise ephemeris of the second satellite and the first observation data at the target time, and determines the difference between the first receiver clock error and the time delay of the transceiver channel of the first satellite at the target time (i.e., the time delay estimated value) as the satellite clock error (i.e., the first satellite clock error) of the downlink signal of the first satellite at the target time. Specifically, the first satellite clock error of the downlink signal of the first satellite can be determined by the following formula:

[0048]

[0049] In the formula, is the above-mentioned first satellite clock error, is the above-mentioned first receiver clock error, is the above-mentioned time delay estimated value, and t is the above-mentioned target time.

[0050] Optionally, the execution subject of the above steps may be a background processor, or other devices with similar processing capabilities, or may also be a machine integrated with at least an image acquisition device and a data processing device. Among them, the image acquisition device may include a graphic acquisition module such as a camera, and the data processing device may include terminals such as a computer and a mobile phone, but is not limited thereto.

[0051] Through the above steps, when the low-earth orbit navigation satellite (i.e., the first satellite) runs outside the target area, the low-earth orbit navigation satellite receives the precise ephemeris and the observation data of the on-board receiver (i.e., the first observation data) from the GNSS satellite (i.e., the second satellite), determines the receiver clock error (i.e., the first receiver clock error) of the low-earth orbit navigation satellite, and at the same time, the low-earth orbit navigation satellite fits the time delay of the transceiver channel of the low-earth orbit navigation satellite (i.e., the time delay estimated value) based on the target time, and determines the difference between the receiver clock error of the low-earth orbit navigation satellite and the time delay of the transceiver channel of the low-earth orbit navigation satellite as the satellite clock error (i.e., the first satellite clock error) of the downlink signal of the low-earth orbit navigation satellite when it is outside the target area.

[0052] By simulating the time delay of the transceiver channels of the LEO navigation satellite at the target time and accurately generating the satellite clock error of the downlink signal based on the time delay of the transceiver channels, it effectively avoids the problem that the time delay of the transceiver channels of the LEO navigation satellite cannot be obtained through monitoring data due to the inability to deploy ground monitoring equipment outside the target area, resulting in the inability to generate the satellite clock error of the downlink signal, solves the problem in the related technology that the satellite clock error cannot be directly extracted based on the monitoring data, realizes the generation of the satellite clock error of the downlink signal of the LEO navigation satellite in the area where ground monitoring equipment cannot be deployed, and improves the accuracy of the satellite clock error of the downlink signal of the LEO navigation satellite outside the target area.

[0053] As an optional implementation manner, the first satellite determines the first receiver clock error of the first satellite according to the precise ephemeris and the first observation data, including: the first satellite obtains the target position of the second satellite and the second satellite clock error of the second satellite in the precise ephemeris, where the position of the second satellite at the target time is the target position; the first satellite obtains the first pseudorange and the first carrier phase between the first satellite and the second satellite in the first observation data; the first satellite determines the first position of the first satellite at the first time according to the target position of the second satellite, the second satellite clock error, the first pseudorange and the first carrier phase, where the first time is after the target time; the first satellite determines the first receiver clock error of the first satellite according to the target position of the second satellite, the first position, the second satellite clock error, the first pseudorange and the first carrier phase.

[0054] The above target position may be the operating position of the second satellite at the target time, and this target position may be represented by coordinates, such as (x, y, z), etc.; the above second satellite clock error may be the satellite clock error of the second satellite at the target time; the above first pseudorange may be the ionosphere-free combined pseudorange between the first satellite and the second satellite at the target time. By using the ionosphere-free combined pseudorange, the influence of ionospheric delay on the result can be effectively reduced, and the accuracy and reliability of GNSS positioning can be improved; the above first carrier phase may be the carrier phase between the first satellite and the second satellite at the target time, and this carrier phase may be the phase difference of the signal transmitted between the first satellite and the second satellite; the above first position may be the operating position of the first satellite at the first time, and this operating position may be represented by coordinates, such as (x, y, z), etc., where the first time is a time after the target time.

[0055] Based on the target position of the second satellite, the second satellite clock error of the second satellite obtained from the precise message, and the first pseudorange and first carrier phase between the first satellite and the second satellite obtained from the first observation data, the first satellite can obtain the running position and running speed at the target time through precise orbit determination by the simplified dynamics method. Thus, the first satellite can short-term predict the first position at the next moment (i.e., the first moment) based on the running position and running speed at the target time. Then, by using the predicted first position, the target position of the second satellite, the second satellite clock error of the second satellite, the first pseudorange, and the first carrier phase, the first receiver clock error of the first satellite is determined by using the Kalman filter. By accurately predicting the position of the low-earth orbit navigation satellite, the error in the calculation can be reduced, and the receiver clock error of the spaceborne receiver can be determined more accurately, thereby improving the response speed and real-time performance of the navigation system and enhancing the positioning accuracy of the navigation system. Specifically, the calculation can be carried out through the following formula:

[0056]

[0057]

[0058] In the formula, g represents the above-mentioned second satellite, s represents the above-mentioned first satellite, IF represents the ionosphere-free combination, is the above-mentioned first pseudorange, is the above-mentioned first carrier phase, is the geometric distance between the above-mentioned second satellite and the spaceborne receiver of the above-mentioned first satellite, and this geometric distance is calculated based on the above-mentioned first position and the above-mentioned target position through the distance formula, is the speed of light in vacuum, is the above-mentioned first receiver clock error, is the above-mentioned second satellite clock error, is the ionosphere-free combination carrier wavelength of the above-mentioned second satellite, is the carrier phase ambiguity between the above-mentioned first satellite and the above-mentioned second satellite, is the other modelable error in the above-mentioned first pseudorange, is the other modelable error in the above-mentioned first carrier phase, is the observation noise, multipath effect, and other unmodeled errors of the ionosphere-free combination of the above-mentioned first pseudorange, is the observation noise, multipath effect, and other unmodeled errors of the ionosphere-free combination of the above-mentioned first carrier phase.

[0059] As an alternative implementation, determining the time delay estimation value according to the target time difference includes: The first satellite obtains a time delay function from the ground data processing center, where the time delay function is obtained by fitting the time delay of the transceiver channel of the first satellite by the ground data processing center; The first satellite determines the time delay estimation value according to the target time difference and the time delay function.

[0060] The above-mentioned ground data processing center can be a set of high-performance computers and software systems. The ground data processing center is deployed on the ground and is responsible for receiving, processing, and distributing positioning data from satellites; The above-mentioned time delay function can be a function expression representing the time delay of the transceiver channel of the first satellite. The time delay function can be obtained by fitting the time delay of the transceiver channel of the first satellite. Through this time delay function and the target time (or the target time difference), the time delay of the transceiver channel of the first satellite at the target time (i.e., the time delay estimation value) can be determined. Among them, the time delay of the transceiver channel used by the fitting function can be sampled by ground monitoring equipment when the first satellite is within the target area. When the first satellite is within the target area, the ground data processing center fits the time delay function according to the sampled time delay of the transceiver channel of the first satellite, and before the first satellite leaves the target area, sends the time delay function to the first satellite, so that the first satellite can accurately estimate the time delay of the transceiver channel outside the target area, and estimate the time delay of the transceiver channel of the first satellite at the target time through the target time difference (or the target time), thereby accurately generating the satellite clock error of the downlink signal of the first satellite, achieving the on-board fast and autonomous generation of the precise clock error of the low-orbit navigation satellite in the global full arc segment under the condition of only deploying ground monitoring equipment within the target area, and avoiding the problem of being unable to deploy ground monitoring equipment globally.

[0061] As an alternative implementation, the above method further includes: The ground data processing center obtains the time delay function by the following method: The ground data processing center determines the time delays of the transceiver channel of the first satellite at multiple time points to obtain a time delay set, where the multiple time points are before the target time; The ground data processing center fits each time delay in the time delay set through the multiple time points to obtain the time delay function.

[0062] The above-mentioned multiple time points may be the time points for sampling the time delay of the transceiver channels of the first satellite. Among them, the adjacent time points among the multiple time points may be separated by a preset time period or may be random multiple time points, and all the multiple time points are before the target moment. When the first satellite is within the target area, the ground data processing center determines the time delays of the transceiver channels of the first satellite at multiple epochs (i.e., multiple time points), obtains a time delay set, sorts the multiple time delays in the time delay set according to the sampling time sequence, obtains a time delay sequence of the transceiver channels of the first satellite, and fits the time delay sequence to obtain a time delay function. The specifically obtained time delay function may be as described below:

[0063]

[0064] In the formula, s is the above-mentioned first satellite, is the time delay of the transceiver channel of the above-mentioned first satellite at time t, and this time delay takes into account the comprehensive influence of the periodic term and the trend term, is the first fitting coefficient, is the second fitting coefficient, is the third fitting coefficient, is the period length of the time delay sequence spectrum of the transceiver channel of the above-mentioned first satellite, is the above-mentioned reference moment, and this reference moment may be the moment when the first satellite last entered the target area, is the polynomial degree.

[0065] Since the trend term can show the overall change trend of the data, and the periodic term can capture the periodic changes of the data, making the model more comprehensively reflect the characteristics of the data. By comprehensively considering the comprehensive influence of the periodic term and the trend term, the time delay function can better describe the change law of the time delay of the transceiver channel of the first satellite, improve the accuracy and stability of the time delay function estimation, and thus contribute to accurately generating the satellite clock error of the downlink signal of the first satellite.

[0066] It should be noted that the above-mentioned obtained time delay function by fitting is only a preferred embodiment, and the form of the specific function can be increased or decreased in terms of the polynomial degree according to the actual situation, or the periodic function can be modified and deleted.

[0067] As an optional implementation, the ground data processing center determines the time delays of the transceiver channels of the first satellite at multiple time points, including: the ground data processing center determines the time delay of the transceiver channel of the first satellite at the k-th time point in the following manner, where k is an integer and the k-th time point is any time point among the multiple time points: the ground data processing center determines the second receiver clock offset of the first satellite at the k-th time point; the ground data processing center determines the third satellite clock offset of the first satellite at the k-th time point; the ground data processing center determines the difference between the second receiver clock offset and the third satellite clock offset of the first satellite as the time delay of the transceiver channel of the first satellite at the k-th time point.

[0068] The above-mentioned k-th time point can be any time point among the multiple time points, and this time point is before the target moment and is the time point when the first satellite is located within the target area; the above-mentioned second receiver clock offset can be the receiver clock offset of the on-board receiver of the first satellite at the k-th time point, and this receiver clock offset can be the time difference between the internal clock of the on-board receiver and the navigation signal sent by the satellite. The satellite clock offset of the downlink signal of the satellite can be determined through the on-board receiver clock offset of the satellite; the above-mentioned third satellite clock offset can be the satellite clock offset of the downlink signal of the first satellite at the k-th time point, that is, the satellite clock offset of the downlink signal when the first satellite is operating within the target area.

[0069] The ground data processing center respectively determines the second receiver clock offset of the first satellite at the k-th time point and the third satellite clock offset of the first satellite at the k-th time point, and determines the difference between the second receiver clock offset and the third satellite clock offset of the first satellite as the time delay of the transceiver channel of the first satellite at the k-th time point. Specifically, it can be obtained through the following formula:

[0070]

[0071] In the formula, is the above-mentioned k-th time point, and this time point is the time point when the first satellite is located within the target area, is the time delay of the transceiver channel of the first satellite at the k-th time point, is the second receiver clock offset of the first satellite at the k-th time point, is the third satellite clock offset of the first satellite at the k-th time point.

[0072] As an optional implementation, the ground data processing center determines the third satellite clock error of the first satellite at the k-th time point, including: the ground data processing center obtains the second pseudorange and the second carrier phase between the first satellite and the ground navigation terminal in the second observation data, where the second observation data is the data obtained at the k-th time point; the ground data processing center determines the second position of the first satellite at the second moment, where the second moment is the moment after the k-th time point; the third satellite clock error is determined according to the second pseudorange, the second carrier phase and the second position.

[0073] The above-mentioned ground navigation terminal can be a device that receives satellite signals and calculates position information. This ground navigation terminal can receive signals from satellites and send the satellite signals to the ground data processing center; the above-mentioned second observation data can be the observation data of the downlink signal of the first satellite at the k-th time point. This data is usually signal data from the ground, including the position, speed, attitude, dual-frequency pseudorange, carrier phase, and other relevant information of the satellite, etc.; the above-mentioned second pseudorange can be the ionosphere-free combined pseudorange between the first satellite and the ground navigation terminal at the k-th time point. By using the ionosphere-free combined pseudorange, the influence of ionospheric delay on the result can be effectively reduced, and the accuracy and reliability of satellite positioning can be improved; the above-mentioned second carrier phase can be the carrier phase between the first satellite and the ground navigation terminal at the k-th time point. This carrier phase can be the phase difference of the signal transmitted between the first satellite and the ground navigation terminal; the above-mentioned second position can be the operating position of the first satellite at the second moment. This operating position can be marked by coordinates, such as (x, y, z), etc., where the second moment is the moment after the k-th time point; the above-mentioned third satellite clock error can be the satellite clock error of the downlink signal of the first satellite at the k-th time point, that is, the satellite clock error of the downlink signal when the first satellite is operating in the target area.

[0074] The ground data processing center receives the second observation data of the first satellite at the k-th time point through the ground navigation terminal, and simultaneously short-term forecasts the second position of the first satellite at the second moment. Based on the second observation data and the second position, Kalman filtering or least squares is used, and a barycentric reference constraint is imposed to determine the third satellite clock error, that is, the satellite clock error of the downlink signal when the first satellite is located in the target area. By imposing a barycentric reference constraint, error accumulation can be reduced, the influence of external interference on signal transmission can be reduced, the accuracy of signal transmission can be improved, and thus a more accurate satellite clock error of the downlink signal can be generated, improving the accuracy of satellite positioning.

[0075] Specifically, it can be obtained through the following formula:

[0076]

[0077]

[0078] In the formula, s represents the above-mentioned first satellite, r represents the ground navigation terminal, IF represents the ionosphere-free combination, is the above-mentioned second pseudorange, is the above-mentioned second carrier phase, is the geometric distance between the above-mentioned ground navigation terminal and the on-board receiver of the above-mentioned first satellite, which is calculated by the distance formula based on the above-mentioned second position and the position of the ground navigation terminal (default known value), c is the speed of light in vacuum, is the receiver clock error of the ground navigation terminal, is the above-mentioned third satellite clock error, is the tropospheric projection function, is the zenith tropospheric wet delay, is the ionosphere-free combination carrier wavelength of the above-mentioned first satellite, is the carrier phase ambiguity between the above-mentioned first satellite and the above-mentioned ground navigation terminal, is the other modelable errors in the above-mentioned second pseudorange, is the other modelable errors in the above-mentioned second carrier phase, is the observation noise, multipath effect and other unmodeled errors of the ionosphere-free combination of the above-mentioned second pseudorange, is the observation noise, multipath effect and other unmodeled errors of the ionosphere-free combination of the above-mentioned second carrier phase.

[0079] In the above formula, there are four parameters to be solved, which are , , , , among which, and are linearly correlated. Therefore, in order to avoid the phenomenon of rank deficiency of the equation, it is necessary to impose a barycentric reference constraint on the equation, that is, take the receiver clock error of a receiver with an external high-precision atomic clock in the ground navigation terminal as the clock error reference, set its receiver clock error to 0, estimate the relative clock errors between the receivers of other ground navigation terminals and the low-earth orbit navigation satellite (i.e., the first satellite) and the selected reference clock. At the same time, in order to ensure the estimation accuracy, it is necessary to synchronously observe the same low-earth orbit navigation satellite by multiple ground navigation terminals (generally the number ≥5) in the same time period, so as to solve other parameters to be solved through Kalman filtering or least squares.

[0080] As an optional implementation manner, the ground data processing center determines the second position of the first satellite at the second moment, including: the ground data processing center receives the target precise message and the third observation data from the second satellite at the k-th time point; the ground data processing center obtains the position of the second satellite at the k-th time point and the fourth satellite clock error of the second satellite in the target precise message; the ground data processing center obtains the third pseudorange and the third carrier phase between the first satellite and the second satellite in the third observation data; the ground data processing center determines the second position of the first satellite at the second moment according to the position of the second satellite at the k-th time point, the fourth satellite clock error, the third pseudorange and the third carrier phase.

[0081] The above-mentioned target precise message may be information with high confidentiality and accuracy transmitted through a satellite. The precise message includes the precise satellite orbit, precise satellite clock error, code bias, etc. of the second satellite at the k-th time point; the above-mentioned third observation signal may be the observation data of the on-board receiver of the second satellite at the k-th time point. This data is usually signal data from other satellites, including the position, speed, attitude, dual-frequency pseudorange, carrier phase, and other relevant information of the satellite, etc.; the above-mentioned position at the k-th time point may be the running position of the second satellite at the k-th time point, and this running position can be represented by coordinates, such as (x, y, z), etc.; the above-mentioned fourth satellite clock error may be the satellite clock error of the second satellite at the k-th time point; the above-mentioned third pseudorange may be the ionosphere-free combined pseudorange between the first satellite and the second satellite at the k-th time point. By using the ionosphere-free combined pseudorange, the influence of ionospheric delay on the result can be effectively reduced, and the accuracy and reliability of GNSS positioning can be improved; the above-mentioned third pseudorange may be the carrier phase between the first satellite and the second satellite at the k-th time point, and this carrier phase may be the phase difference of the signal transmitted between the first satellite and the second satellite.

[0082] Based on obtaining the position of the second satellite at the k-th time point and the fourth satellite clock error of the second satellite in the target precise message, and obtaining the third pseudorange and the third carrier phase between the first satellite and the second satellite in the third observation data, the ground data processing center can obtain the running position and running speed of the first satellite at the k-th time point through precise orbit determination by the simplified dynamics method. Thus, the first satellite short-term forecasts the second position of the first satellite at the next moment (i.e., the second moment) according to the running position and running speed of the first satellite at the current moment (i.e., the k-th time point). Specifically, the calculation formula in the above-mentioned embodiment can be referred to. By accurately predicting the position of the low-earth orbit navigation satellite, the error in the calculation can be reduced, which is beneficial to more accurately determining the receiver clock error of the on-board receiver, thereby improving the response speed and real-time performance of the navigation system and enhancing the positioning accuracy of the navigation system.

[0083] As an optional implementation, the ground data processing center determines the second receiver clock offset of the first satellite at the k-th time point, including: the ground data processing center determines the second receiver clock offset of the first satellite at the k-th time point according to the position of the second satellite at the k-th time point, the second position, the fourth satellite clock offset, the third pseudorange, and the third carrier phase.

[0084] After the ground data processing center short-term forecasts the second position of the first satellite at the second moment, based on the forecasted second position, the position of the second satellite at the k-th time point, the fourth satellite clock offset of the second satellite, the third pseudorange, and the third carrier phase, the ground data processing center uses Kalman filtering for estimation to determine the second receiver clock offset of the first satellite. Specifically, the calculation formula in the above embodiment can be referred to.

[0085] As an optional implementation, the first satellite and the second satellite belong to navigation satellites.

[0086] As an optional implementation, Figure 4 is a schematic flow chart of generating the satellite clock offset of the downlink signal of a low-earth orbit navigation satellite according to an embodiment of the present invention, as Figure 4 shown, and the specific process is as follows:

[0087] Step S1, after the low-earth orbit satellite (i.e., the first satellite) enters the target area, the ground data processing center receives the precise ephemeris of the GNSS satellite (i.e., the target current ephemeris) and the on-board GNSS receiver observation data (i.e., the third observation data) transmitted back by the GNSS satellite (i.e., the second satellite) through the ground injection station and the space-ground link;

[0088] Step S2, the ground data processing center synchronously receives the observation data of the downlink signal of the low-earth orbit navigation satellite (i.e., the second observation data) collected by the ground navigation terminal;

[0089] Step S3, based on the on-board data (i.e., the target current ephemeris and the third observation data), through the simplified dynamics method, precise orbit determination of the low-earth orbit satellite (i.e., the first satellite) is carried out to obtain the precise orbit of the low-earth orbit satellite (i.e., the first satellite) in the target area period and short-term forecast the second position;

[0090] Step S4, constraining the GNSS orbit clock offset (i.e., the fourth satellite clock offset) and the low-earth orbit satellite orbit (i.e., the second position) in the target area period, based on the precise ephemeris of the GNSS satellite (i.e., the target current ephemeris, specifically, it can be the position at the k-th time point) and the on-board GNSS receiver observation data (i.e., the third observation data, specifically, it can be the third pseudorange and the third carrier phase), using Kalman filtering for estimation to calculate the on-board GNSS receiver clock offset of the low-earth orbit satellite (i.e., the second receiver clock offset) in the target area period;

[0091] Step S5: Constrain the ground terminal coordinates (i.e., the position of the ground navigation terminal) within the target area and the low-Earth orbit satellite orbit (i.e., the second position). Based on the downlink signal observation data of the low-Earth orbit navigation satellite (i.e., the second observation data, specifically the second pseudorange and the second carrier phase), use Kalman filtering or least squares and apply the centroid reference constraint to calculate the satellite clock offset of the low-Earth orbit downlink signal during the target area period (i.e., the third satellite clock offset).

[0092] Step S6: Subtract the clock offsets of the low-Earth orbit satellite-borne GNSS receivers (i.e., the second receiver clock offsets) at multiple epochs (i.e., multiple time points) from the corresponding downlink signal clock offset (i.e., the third satellite clock offset) sequence to obtain the low-Earth orbit navigation satellite transceiver channel delay sequence (i.e., the delay set).

[0093] Step S7: Fit the low-Earth orbit navigation satellite transceiver channel delay sequence to obtain the low-Earth orbit navigation satellite transceiver channel delay function (i.e., the delay function). Before the low-Earth orbit satellite leaves the target area, the ground data processing center uploads the delay function to the low-Earth orbit satellite (i.e., the first satellite) through the ground uplink station and the space-ground uplink link.

[0094] Step S8: After the low-Earth orbit satellite (i.e., the first satellite) exits the target area (i.e., leaves the target area), based on the on-board data (i.e., the current telemetry and the first observation data), perform precise orbit determination of the low-Earth orbit satellite autonomously on board through the simplified dynamics method to obtain the precise orbit of the low-Earth orbit navigation satellite outside the target area period and short-term predict the first position.

[0095] Step S9: Constrain the GNSS orbit clock offset (i.e., the second satellite clock offset) and the low-Earth orbit satellite orbit (i.e., the first position) outside the target area period. Based on the precise GNSS satellite ephemeris (i.e., the precise ephemeris, specifically the target position) and the on-board GNSS receiver observation data (i.e., the first observation data, specifically the first pseudorange and the first carrier phase), use Kalman filtering for estimation and calculate the clock offset of the low-Earth orbit satellite-borne GNSS receiver (i.e., the first receiver clock offset) autonomously on board outside the target area period.

[0096] Step S10: Outside the target area period, the low-Earth orbit satellite autonomously on board uses the clock offset of the on-board GNSS receiver (i.e., the first receiver clock offset) to subtract the corresponding transceiver channel delay (i.e., the delay estimated value) to calculate the downlink signal satellite clock offset (i.e., the first satellite clock offset).

[0097] Through the above method, it is possible to generate the global precise clock offset of the low-Earth orbit navigation satellite only by using the measurement data of the ground monitoring equipment and the low-Earth orbit satellite-borne GNSS receivers deployed within the target area.

[0098] Through the description of the above embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be implemented by means of software plus a necessary general hardware platform. Of course, it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions for causing a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in various embodiments of the present invention.

[0099] In this embodiment, a device for determining satellite clock error is also provided. This device is used to implement the above embodiments and preferred implementation methods, and those that have been described will not be repeated. Although the device described in the following embodiments is preferably implemented by software, implementation by hardware, or a combination of software and hardware is also possible and contemplated.

[0100] Figure 5 is a structural block diagram of a device for determining satellite clock error according to an embodiment of the present invention. As Figure 5 shown, the device 50 is applied to the above-mentioned first satellite and includes: a memory 502, a processor 504, and a computer program stored on the above-mentioned memory and executable on the above-mentioned processor. When the above-mentioned processor executes the above-mentioned computer program, the following operations are implemented: receiving precise ephemeris and first observation data from a second satellite, where the operating orbit of the second satellite is higher than that of the first satellite, the first satellite is located outside the target area at the target time, and the first observation data is data obtained at the target time; obtaining a target time difference through the target time and a reference time, and determining a delay estimation value according to the target time difference, where the reference time is the time when the first satellite last entered the target area; determining the first satellite clock error of the first satellite through the delay estimation value, precise ephemeris, and first observation data.

[0101] In an exemplary embodiment, when the above-mentioned processor 504 executes the above-mentioned computer program, it is further used to implement the following operations: determining the first receiver clock error of the first satellite according to the precise ephemeris and first observation data; determining the difference between the first receiver clock error and the delay estimation value as the first satellite clock error of the downlink signal of the first satellite.

[0102] In an exemplary embodiment, when the above-mentioned processor 504 executes the above-mentioned computer program, it is further used to implement the following operations: obtaining the target position of the second satellite and the second satellite clock offset of the second satellite in the precision telegram, where the position of the second satellite at the target moment is the target position; obtaining the first pseudorange and the first carrier phase between the first satellite and the second satellite in the first observation data; determining the first position of the first satellite at the first moment according to the target position of the second satellite, the second satellite clock offset, the first pseudorange and the first carrier phase, where the first moment is after the target moment; determining the first receiver clock offset of the first satellite according to the target position of the second satellite, the first position, the second satellite clock offset, the first pseudorange and the first carrier phase.

[0103] In an exemplary embodiment, when the above-mentioned processor 504 executes the above-mentioned computer program, it is further used to implement the following operations: obtaining the delay function from the ground data processing center, where the delay function is obtained by fitting the delay of the first satellite's transceiver channel by the ground data processing center; determining the delay estimation value according to the target time difference and the delay function.

[0104] In an exemplary embodiment, the above-mentioned ground data processing center is further used to obtain the delay function by the following method: determining the delays of the first satellite's transceiver channel at multiple time points to obtain a delay set, where the multiple time points are before the target moment; fitting each delay in the delay set through the multiple time points to obtain the delay function.

[0105] In an exemplary embodiment, the above-mentioned ground data processing center is further used to determine the delay of the first satellite's transceiver channel at the kth time point by the following method, where k is an integer and the kth time point is any time point among the multiple time points: determining the second receiver clock offset of the first satellite at the kth time point; determining the third satellite clock offset of the first satellite at the kth time point; determining the difference between the second receiver clock offset and the third satellite clock offset of the first satellite as the delay of the first satellite's transceiver channel at the kth time point.

[0106] In an exemplary embodiment, the above-mentioned ground data processing center is further used to obtain the second pseudorange and the second carrier phase between the first satellite and the ground navigation terminal in the second observation data, where the second observation data is the data obtained at the kth time point; determining the second position of the first satellite at the second moment, where the second moment is the moment after the kth time point; determining the third satellite clock offset according to the second pseudorange, the second carrier phase and the second position.

[0107] In an exemplary embodiment, the first satellite and the second satellite belong to navigation satellites.

[0108] Embodiments of the present invention also provide a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of the method described above in any one of the above.

[0109] In an exemplary embodiment, the above computer-readable storage medium may include, but is not limited to: various media such as USB flash drives, read-only memories (ROMs), random access memories (RAMs), external hard drives, magnetic disks, or optical discs that can store computer programs.

[0110] Embodiments of the present invention also provide an electronic device including a memory and a processor, where the memory stores a computer program, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0111] In an exemplary embodiment, the above electronic device may further include a transmission device and an input / output device, where the transmission device is connected to the above processor, and the input / output device is connected to the above processor.

[0112] Embodiments of the present invention also provide a computer program product including a computer program, where the computer program, when executed by a processor, implements the steps of the above method in various embodiments of the present application.

[0113] Specific examples in this embodiment may refer to the examples described in the above embodiments and exemplary embodiments, and will not be repeated here.

[0114] Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device. They can be concentrated on a single computing device or distributed on a network composed of multiple computing devices. They can be implemented by program codes executable by the computing device, so that they can be stored in a storage device and executed by the computing device. And in some cases, the steps shown or described can be executed in a different order than here, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module to implement. Thus, the present invention is not limited to any specific combination of hardware and software.

[0115] The above are only preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for determining satellite clock error, characterized in that, including: The first satellite receives precise ephemeris and first observation data from the second satellite, where the operating orbit of the second satellite is higher than that of the first satellite, the first satellite is located outside the target area at the target time, and the first observation data is the data obtained at the target time; The first satellite obtains a target time difference through the target time and a reference time, and determines a time delay estimation value according to the target time difference, where the reference time is the time when the first satellite last entered the target area; The first satellite determines a first satellite clock offset of the first satellite through the time delay estimation value, the precise ephemeris, and the first observation data; wherein the first satellite determines the first satellite clock offset of the first satellite through the time delay estimation value, the precise ephemeris, and the first observation data, including: The first satellite determines a first receiver clock offset of the first satellite according to the precise ephemeris and the first observation data; The first satellite determines the difference between the first receiver clock offset and the time delay estimation value as the first satellite clock offset of the downlink signal of the first satellite; Determining the time delay estimation value according to the target time difference includes: The first satellite obtains a time delay function from the ground data processing center, where the time delay function is obtained by fitting the time delay of the transceiver channel of the first satellite by the ground data processing center; The first satellite determines the time delay estimation value according to the target time difference and the time delay function.

2. The method according to claim 1, wherein The first satellite determines the first receiver clock offset of the first satellite according to the precise ephemeris and the first observation data, including: The first satellite obtains the target position of the second satellite and the second satellite clock offset of the second satellite in the precise ephemeris, where the position of the second satellite at the target time is the target position; The first satellite obtains a first pseudorange and a first carrier phase between the first satellite and the second satellite in the first observation data; The first satellite determines a first position of the first satellite at a first time according to the target position of the second satellite, the second satellite clock offset, the first pseudorange, and the first carrier phase, where the first time is after the target time; The first satellite determines the first receiver clock offset of the first satellite according to the target position of the second satellite, the first position, the second satellite clock offset, the first pseudorange, and the first carrier phase.

3. The method according to claim 1, characterized in that, The method further includes: The ground data processing center obtains the time delay function by the following method: The ground data processing center determines the time delays of the transceiver channel of the first satellite at multiple time points to obtain a time delay set, where the multiple time points are before the target time; The ground data processing center fits each of the time delays in the time delay set through the multiple time points to obtain the time delay function.

4. The method according to claim 3, wherein The ground data processing center determines the time delays of the transceiver channel of the first satellite at multiple time points, including: The ground data processing center determines the time delay of the transceiver channel of the first satellite at the k-th time point in the following manner, where k is an integer and the k-th time point is any time point among the multiple time points: The ground data processing center determines the second receiver clock error of the first satellite at the k-th time point; The ground data processing center determines the third satellite clock error of the first satellite at the k-th time point; The ground data processing center determines the difference between the second receiver clock error and the third satellite clock error of the first satellite as the time delay of the transceiver channel of the first satellite at the k-th time point.

5. The method according to claim 4, characterized in that, The ground data processing center determines the third satellite clock error of the first satellite at the k-th time point, including: The ground data processing center obtains the second pseudorange and the second carrier phase between the first satellite and the ground navigation terminal in the second observation data, where the second observation data is the data obtained at the k-th time point; The ground data processing center determines the second position of the first satellite at the second moment, where the second moment is the moment after the k-th time point; The third satellite clock error is determined based on the second pseudorange, the second carrier phase, and the second position.

6. The method according to claim 1, characterized in that The first satellite and the second satellite belong to navigation satellites.

7. A device for determining satellite clock offset, characterized in that Applied to the first satellite, it includes: a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the following operations are implemented: Receiving precise ephemeris and first observation data from the second satellite, where the operating orbit of the second satellite is higher than that of the first satellite, the first satellite is outside the target area at the target moment, and the first observation data is the data obtained at the target moment; Obtaining a target time difference through the target moment and a reference moment, and determining a time delay estimation value based on the target time difference, where the reference moment is the moment when the first satellite last entered the target area; Determining the first satellite clock error of the first satellite based on the time delay estimation value, the precise ephemeris, and the first observation data; When the processor executes the computer program, it is also used to implement the following operations: determining the first receiver clock error of the first satellite based on the precise ephemeris and the first observation data; determining the difference between the first receiver clock error and the time delay estimation value as the first satellite clock error of the downlink signal of the first satellite; When the processor executes the computer program, it is also used to implement the following operations: obtaining a time delay function from the ground data processing center, where the time delay function is obtained by fitting the time delay of the transceiver channel of the first satellite; determining the time delay estimation value based on the target time difference and the time delay function.

8. A computer-readable storage medium, characterized in that, A computer program is stored in the computer-readable storage medium, where when the computer program is executed by the processor, the steps of the method described in any one of claims 1 to 6 are implemented.

9. An electronic device, comprising a memory and a processor, characterized in that, A computer program is stored in the memory, and the processor is configured to run the computer program to execute the method described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, the steps of the method described in any one of claims 1 to 6 are implemented.

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