CN117826568A - Time service providing method and device - Google Patents

Time service providing method and device Download PDF

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Publication number
CN117826568A
CN117826568A CN202311640271.9A CN202311640271A CN117826568A CN 117826568 A CN117826568 A CN 117826568A CN 202311640271 A CN202311640271 A CN 202311640271A CN 117826568 A CN117826568 A CN 117826568A
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China
Prior art keywords
ionospheric
satellite
error model
model value
value
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Chinese (zh)
Inventor
李丽媛
王献中
曾向航
温丽芳
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Unicore Communications Inc
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Unicore Communications Inc
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Priority to CN202311640271.9A priority Critical patent/CN117826568A/en
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    • G—PHYSICS
    • G04—HOROLOGY
    • G04R—RADIO-CONTROLLED TIME-PIECES
    • G04R20/00—Setting the time according to the time information carried or implied by the radio signal
    • G04R20/02—Setting the time according to the time information carried or implied by the radio signal the radio signal being sent by a satellite, e.g. GPS
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/03—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers
    • G01S19/07—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers providing data for correcting measured positioning data, e.g. DGPS [differential GPS] or ionosphere corrections
    • G01S19/072—Ionosphere corrections
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
    • G01S19/25—Acquisition or tracking or demodulation of signals transmitted by the system involving aiding data received from a cooperating element, e.g. assisted GPS
    • G01S19/256—Acquisition or tracking or demodulation of signals transmitted by the system involving aiding data received from a cooperating element, e.g. assisted GPS relating to timing, e.g. time of week, code phase, timing offset
    • G—PHYSICS
    • G04—HOROLOGY
    • G04R—RADIO-CONTROLLED TIME-PIECES
    • G04R20/00—Setting the time according to the time information carried or implied by the radio signal
    • G04R20/02—Setting the time according to the time information carried or implied by the radio signal the radio signal being sent by a satellite, e.g. GPS
    • G04R20/06—Decoding time data; Circuits therefor

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  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Position Fixing By Use Of Radio Waves (AREA)

Abstract

The application discloses a time service providing method and device, in the position and time service resolving of a GNSS receiver of a user, the real-time broadcast ionosphere model of each GNSS system is fully utilized, the optimal improvement of real-time ionosphere errors is ensured, and in addition, the GNSS positioning and time service with higher precision, continuity and stability is provided for the user without adding extra complex operation amount, so that the multi-system GNSS satellite positioning is supported. More preferably, when the ionosphere parameters are switched, the deviation caused by the model errors is calculated according to the two groups of parameters before and after the switching, so that the position and clock error jump when the ionosphere errors are changed by different parameters and models is eliminated, and the precision and reliability of the position and clock error are effectively improved.

Description

Time service providing method and device
Technical Field
The present disclosure relates to, but not limited to, satellite navigation technologies, and in particular, to a time service providing method and apparatus.
Background
With the rapid development of modern technological information technology, the requirements on the precision and reliability of time are higher and higher in various industries such as communication, electric power, traffic, national defense and the like, and a high-precision time reference becomes a basic guarantee in the fields such as communication, electric power, broadcast television, security monitoring, industrial control and the like. Satellite navigation Positioning system (GNSS, global Navigation Satellite System) satellites can provide all-weather high-precision Positioning, navigation and timing (Navigation and Timing) services for global users, and applications based on GNSS satellite timing are becoming more and more widespread worldwide.
The GNSS timing Method includes a Single-Station Method (Single-Station Method). The single-station method does not need synchronous observation, the number of users is not limited, and the use is flexible and convenient. For a single-station user, the ionospheric delay error is one of main error sources affecting the satellite PNT service, and the ionospheric error correction algorithm is a key factor affecting the positioning and timing accuracy of the user. For single-station GNSS applications, ionospheric errors may be eliminated by combining observables of dual-frequency carriers or pseudoranges, but single-station methods are not suitable for single-frequency users because single-frequency GNSS receivers are more susceptible to ionospheric delay errors due to their limitations in signal processing and correction.
How to improve the position and time service performance of a GNSS receiver and provide a more accurate and robust GNSS service for users is a technical problem to be solved.
Disclosure of Invention
The time service providing method and device can improve the time service performance of the GNSS receiver, so that higher-precision and more-stable GNSS service is provided for users.
The embodiment of the application provides a time service providing method, which comprises the following steps:
determining a first ionospheric error model value of each satellite corresponding to the stored first ionospheric parameter information at the current moment, and determining a second ionospheric error model value of each satellite corresponding to the second ionospheric parameter information obtained by analyzing at the current moment;
and providing time service by using the first ionosphere error model value and the second ionosphere error model value.
Embodiments of the present application also provide a computer-readable storage medium storing computer-executable instructions for performing the time service providing method described in any one of the above.
The embodiment of the application further provides a time service providing device, which comprises a memory and a processor, wherein the memory stores the following instructions executable by the processor: a step for executing the time service providing method according to any one of the above.
According to the time service providing method and device, in time service resolving of the GNSS receiver of the user, the real-time ionosphere model of each GNSS system is fully utilized, the optimal improvement of real-time ionosphere errors is guaranteed, and in addition, the GNSS positioning and time service with higher precision, continuity and stability is provided for the user without adding additional complex operation amount, so that the multi-system GNSS satellite positioning is supported.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
The accompanying drawings are included to provide a further understanding of the technical aspects of the present application, and are incorporated in and constitute a part of this specification, illustrate the technical aspects of the present application and together with the examples of the present application, and not constitute a limitation of the technical aspects of the present application.
Fig. 1 is a flow chart of a time service providing method in an embodiment of the present application;
fig. 2 is a flowchart of a first embodiment of a time service providing method according to an embodiment of the present application;
fig. 3 is a flowchart of a second embodiment of a time service providing method according to an embodiment of the present application;
fig. 4 is a schematic structural diagram of a time service providing device in an embodiment of the present application.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the present application more apparent, embodiments of the present application will be described in detail hereinafter with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be arbitrarily combined with each other.
In order to facilitate an understanding of the present application, a more complete description of the present application will now be provided with reference to the relevant figures. Examples of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It is to be understood that the terms "first," "second," and the like, as used herein, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless explicitly defined otherwise.
It is to be understood that in the following embodiments, "connected" is understood to mean "electrically connected", "communicatively connected", etc., if the connected circuits, modules, units, etc., have electrical or data transfer between them.
As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and/or the like, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Also, the term "and/or" as used in this specification includes any and all combinations of the associated listed items.
Ionospheric error is a general concept describing ionospheric error, and ionospheric correction models are mathematical models or algorithms specifically used to correct ionospheric error. The ionospheric correction model is a specific implementation of the ionospheric error model, and the broadcast ionospheric model is a specific type of ionospheric correction model.
Four large global satellite navigation positioning systems employ different broadcast ionosphere models: the global positioning system (GPS, global Positioning System) in the united states uses the Klobuchar model to calculate ionospheric delay on GPS L1 frequency based on geographic latitude, local time, which is currently the most widely used model; the global satellite navigation system Galileo of European Union mainly adopts a Ne-Quick model with three-dimensional electron density, and ionosphere error is directly obtained through integrating the electron density; the Beidou (BeiDou) system in China supports two different broadcast ionosphere correction models, the Beidou second generation adopts a Beidou Klobuchar model, the basic algorithm of the Beidou second generation is basically consistent with that of a GPS Klobuchar model, but the Beidou second generation is different from the GPS model in reference frame and detail, and a BDGIM model is adopted in the Beidou third generation global service.
Satellites of a Beidou satellite navigation system (BDS) broadcast 8 parameters of a Beidou Klobuchar model at B1I and B3I frequency points, and are only suitable for China and peripheral areas, and middle circular earth orbit (MEO) and inclined geosynchronous orbit (IGSO) satellites in a Beidou third constellation broadcast 9 parameters of a BDGIM model at B1c, B2a and B2B frequency points, so that the method is suitable for ionosphere delay correction in the global scope. No model and parameters for estimating ionospheric errors are provided in the russian global satellite navigation system (GLONASS, global Navigation Satellite System) interface file and in the navigation messages, and the ionospheric errors of the GLONASS satellite observables can be estimated by means of models of other systems, and the navigation messages of future GLONASS code division multiple access signals will broadcast 3 ionospheric parameters.
Because the total electronic content of the ionized layer changes along with the change of the altitude, time, season, solar activity intensity and the spatial position of the user, in order to ensure the accuracy of the correction of the ionized layer error model, the broadcast ionized layer parameters of each system are updated in real time according to the monitoring result. The parameters of the Beidou Klobuchar model and the BDGIM model are updated every two hours (2 h), the Galileo Ne-Quick model is updated every 1 day, and the parameters of the GPS Klobuchar model are updated every 1-7 days. In practical engineering application, a single-station GNSS receiver generally analyzes and stores the latest ionosphere parameters in real time, and reads the stored ionosphere parameters for use when the GNSS receiver is started up next time until the new ionosphere parameters are analyzed in the operation process, and then updates, uses and stores the new ionosphere parameters.
Because of the differences of different system models and parameters, the ionospheric models and the broadcasted ionospheric parameters of different GNSS systems have obvious differences when the ionospheric model error values (namely, the difference or deviation between the ionospheric correction value estimated by using the ionospheric model and the actual ionospheric delay) of the same satellite at the same time are calculated, and the consistency analysis of the parameters of each ionospheric model also shows that the same ionospheric model has obvious jump phenomenon when the parameters of the adjacent ionospheric model are updated. The worse the consistency of two adjacent groups of ionosphere model parameters, the larger the ionosphere model error value jump calculated before and after the ionosphere model parameters are updated, the ionosphere model error value jump can directly cause discontinuous time service of a user for single-star time service users, and for multi-star time service users, the positioning and time service accuracy depends on the comprehensive influence of satellite ionosphere delay jump used by the current epoch. Ionospheric model value jumps may also exist at the day and night interface times of the locality, which are not caused by parameter updates, but rather by ionospheric model segment modeling.
Aiming at the problems of positioning and time service result jump caused by ionosphere parameter updating in the operation process after a single station receiver user starts, the positioning and time service resolving of the receiver in a shorter time can keep the use of the first group of ionosphere parameters not updated, can directly avoid the result jump caused by parameter updating, and ensures the stability of the result in a short period. However, for a receiver user operating for a long time, this scheme may result in a decrease in the accuracy of the ionospheric error model after the ionospheric parameters have not been updated for a long time, and thus in a significant decrease in the accuracy of positioning and timing.
The analysis and research related to the ionosphere model mainly comprises analysis or model improvement of ionosphere change characteristics and related modeling methods, analysis of a regional ionosphere model construction method and evaluation of accuracy and performance comparison of different ionosphere models in a specific time period and a specific region by using GNSS data, but the analysis and research related to the ionosphere model in the related technology does not consider the problem of improving position and time service result jump when the traditional various broadcast ionosphere models are used and parameters are updated, and does not provide a solution for guaranteeing the position and time service stability of a single-station single-frequency GNSS user when the models are switched or parameters are updated. For this reason, the method for providing a time service according to the embodiment of the present application, as shown in fig. 1, may include:
step 100: and determining a first ionospheric error model value of each satellite corresponding to the stored first ionospheric parameter information at the current moment, and determining a second ionospheric error model value of each satellite corresponding to the second ionospheric parameter information obtained by analyzing at the current moment.
In one illustrative example, the second ionospheric parameter information is different from the first ionospheric parameter information.
In an illustrative example, the obtaining of the first ionospheric error model value or the second ionospheric error model value in step 100 may include:
acquiring a user observation value of a GNSS receiver at the current moment;
and calculating a first ionospheric error model value or a second ionospheric error model value of each satellite at the current moment according to the obtained user observation value at the current moment and the first ionospheric parameter information or the second ionospheric parameter information.
In one embodiment, the first ionospheric parameter information or the second ionospheric parameter information generally comprises ionospheric model parameters, such as, for example, a Klobuchar model, and may comprise alpha and beta parameters such as, for example, a Klobuchar model.
Step 101: and providing time service by using the first ionosphere error model value and the second ionosphere error model value.
In one illustrative example, step 101 may include:
calculating the receiver clock difference of each satellite at the current moment according to the user observation value, the first ionosphere error model value and the second ionosphere error model value;
and providing time service by adopting the calculated receiver clock error value.
In an exemplary embodiment, the time service providing method provided in the embodiment of the present application further includes:
calculating the deviation of the first ionospheric error model value and the second ionospheric error model value of each satellite;
and correcting the ionospheric errors of the satellites respectively by using the calculated second ionospheric error model value of the satellites or the second ionospheric error model value and the deviation so as to obtain PVT position solutions at the current moment.
In one illustrative example, step 101 may include:
calculating the receiver clock difference of each satellite at the current moment according to the PVT position solution, the first ionosphere error model value and the second ionosphere error model value;
and providing time service by adopting the calculated receiver clock error value.
According to the time service providing method and device, in time service resolving of the GNSS receiver of the user, the real-time broadcast ionosphere model of each GNSS system is fully utilized, the optimal improvement of real-time ionosphere errors is guaranteed, and in addition, the GNSS positioning and time service with higher precision, continuity and stability is provided for the user without adding additional complex operation amount, so that the multi-system GNSS satellite positioning is supported.
Fig. 2 is a flow chart of a first embodiment of a time service providing method in an embodiment of the present application, and as shown in fig. 2, may include:
step 200: and acquiring a user observation value of the GNSS receiver at the current moment and a stored latest group of first ionospheric parameter information.
In one illustrative example, the current time T k The user observations of the GNSS receiver of (a) may include, for example: and the received satellite signals are subjected to pseudo-range, carrier phase, doppler frequency shift and other information, and the information is used for positioning and navigation calculation. In one embodiment, a receiver observation file or data stream may be selected and ensured to be captured in real time using, for example, GNSS data processing software or tools. In this way, the current time T can be extracted from the software interface or command line k Is a GNSS user observation of (a). The specific implementation may vary from software to software and is not intended to limit the scope of the present application.
In one illustrative example, ionospheric parameters are typically broadcast by GNSS satellites and are updated periodically. In one embodiment, ionosphere parameter information may be extracted and stored using, for example, GNSS data processing software or tools, or from a GNSS broadcast data stream. Stored latest ionospheric parameter information Ion data (A) Ionospheric model parameters are typically included, exemplified by the Klobuchar model, which may include alpha and beta parameters such as the Klobuchar model, and the like.
Step 201: and calculating a first ionosphere error model value of each satellite at the current moment according to the obtained user observation value at the current moment and the first ionosphere parameter information.
In one illustrative example, a first ionospheric error model value Ion A (T k ) The ionosphere model used and the latest set of first ionosphere parameter information Ion data (A) Matching, such as: a latest set of first ionospheric parameter information Ion data (A) Eight parameters parsed from the GPS system, then, useThe ionosphere model of (2) is a GPS Klobuchar model; and the following steps: a latest set of first ionospheric parameter information Ion data (A) Eight parameters are analyzed from the BDS system, and then the ionosphere model is a Beidou Klobuchar model; another example is: a latest set of first ionospheric parameter information Ion data (A) Nine parameters are analyzed from the BDS system, and then the ionosphere model is the Beidou BDGIM model; also as follows: a latest set of first ionospheric parameter information Ion data (A) Is a three-parameter solution from the Galileo system, then the ionosphere model used is the Ne-Quick model or other modified model.
In an exemplary embodiment, if there are multiple sets of ionospheric parameter values that are valid in different systems at the same time, the ionospheric error model value of each satellite at the current time can be calculated by preferentially selecting the ionospheric model and parameters with optimal accuracy in the area where the user is located according to the user location and experience.
The first ionospheric error model value Ion A (T k ) The ionospheric model and parameters used are merely illustrative and are not intended to limit the scope of the present application. That is, the ionosphere model used in step 301 is not limited to the ionosphere model provided by each system interface file, and other modified, applicable ionosphere models, such as the Klobuchar-like model of GPS, the Ne-QuickG or NTCM model of Galileo, or other more applicable models, etc., may be used for the broadcast ionosphere parameters.
In an illustrative example, if a GNSS receiver user is able to receive Satellite based augmentation (SBAS, satellite-Based Augmentation System) signals, then the ionospheric error model values in step 201 may be calculated using the updated grid ionospheric information in real-time and the grid ionospheric model. Furthermore, the broadcast ionospheric parameters may be derived from default values stored by the GNSS receiver or ionospheric parameter values stored on a storage medium, or available ionospheric parameter values may be derived by external configuration or external link transmission.
How to calculate the ionospheric error model value in step 201 belongs to a common technical means of those skilled in the art, and the specific implementation is not used to limit the protection scope of the present application, and is not repeated here.
Step 203: and respectively correcting the ionospheric errors of the satellites by using the calculated first ionospheric error model values of the satellites so as to obtain PVT position solutions at the current moment.
In this step, the PVT Position solution represents an estimate of Position, velocity and time (Position, velocity and Time).
In an exemplary embodiment, the pseudo-range raw observation equation of the GNSS receiver may be expressed in a practical form as shown in the formula (1) with sufficient consideration given to errors related to satellites, errors related to signal propagation, errors at the receiver end, and the like:
P i ＝R i +Ion i (1)
in the formula (1), P i Pseudo-range observables of an ith satellite are represented; ion (Ion) i An ionospheric error model value representing an ith satellite; r is R i Representing the theoretical distance of the ith satellite that contains various other errors in addition to the ionospheric error term. Wherein R is i Can be expressed as shown in formula (2):
in the formula (2), r i Representing the geometric distance between the satellite position of the ith satellite and the receiver; c represents the speed of light;representing the receiver clock error of the ith satellite pseudo-range calculation; />The satellite end clock difference of the ith satellite is represented; tgd i Group delay representing the ith satellite; trop (Trop) i A tropospheric delay representing an ith satellite; epsilon i And the pseudo-range observation noise of the ith satellite is represented. Wherein the satellite position of the ith satellite and the satelliteEnd clock error->And group delay Tgd i All can be obtained by calculation of broadcast ephemeris; tropospheric delay Trop of ith satellite i Can be obtained through model calculation; pseudo-range observation noise epsilon of ith satellite i The attenuation can be neglected by carrier phase smoothing and the like.
In one embodiment, for a current only one set of first ionospheric error model values Ion A (T k ) In the case of (1), ion in formula (1) i For the current time T k First ionospheric error model value Ion for the ith satellite A (T k ) i I.e. Ion i ＝Ion A (T k ) i . At this time, step 103 may include:
by the current time T k First ionospheric error model value Ion for the ith satellite A (T k ) i At the current time T k Ionosphere error correction of the ith satellite is carried out, and the current moment T is calculated in real time through the formula (1) and the formula (2) k PVT position solution X of (2) pvt (T k )。
In an illustrative example, as shown in fig. 3, step 2021 and step 2022 may be further included before step 203:
step 2021: and detecting a new set of second ionospheric parameter information which is resolved at the current moment and is different from the first ionospheric parameter information, and calculating a second ionospheric error model value of each satellite at the current moment by using the second ionospheric parameter information.
In one illustrative example, a new set of second ionospheric parameter information Ion is resolved at the current time of day data (B) The specific steps and operations of (a) may vary depending on the GNSS receiver model number and GNSS data processing software. Typically, the GNSS receiver and data processing software will automatically resolve ionosphere parameters. If a new set of second ionosphere parameter information Ion is detected to be resolved at the current moment data (B) Further, analyzeThe second ionosphere parameter information Ion data (B) And the calculated first ionospheric error model value Ion of each satellite at the current time A (T k ) The parameters (here refer to the calculation of the first ionospheric error model value Ion A (T k ) Parameters used) are different, then the second ionospheric parameter information Ion is utilized data (B) Calculating a second ionospheric error model value Ion of each satellite at the current moment B (T k )。
In one illustrative example, the second ionospheric parameter information Ion is utilized data (B) Calculating a second ionospheric error model value Ion of each satellite at the current moment B (T k ) May include: based on the obtained user observation value at the current moment and the second ionosphere parameter information Ion data (B) Calculating a second ionospheric error model value Ion of each satellite at the current moment B (T k ). Detailed description and step 201 of the first ionospheric error model value Ion A (T k ) Is consistent with the calculation of (c), and will not be described in detail herein.
It should be noted that, the step 2021 resolves a new set of second ionospheric parameter information at the current time, and the step 201 calculates the first ionospheric error model value of each satellite at the current time, which is not strictly sequential, and is not used to limit the protection scope of the present application.
Step 2022: and calculating the deviation of the first ionospheric error model value and the second ionospheric error model value of each satellite.
In an exemplary embodiment, step 2022 calculates and stores the second ionospheric error model values Ion for each satellite separately B (T k ) And a first ionospheric error model value Ion A (T k ) To obtain a first ionospheric error model value Ion A (T k ) And a second ionospheric error model value Ion B (T k ) Deviation deltaion of (a) B-A (T k )。
In the embodiment of the present application, the two sets of ionospheric parameters, namely, the first ionospheric parameter information Ion data (A) And second ionospheric parameter information Ion data (B) The parameters may be the same type of parameters from the same system or different types of parameters from different systems. The ionosphere parameters and model correction rate statistics result of each system are above 50%, in general, except that eight parameters of the Beidou Klobuchar model mainly provide ionosphere error correction of China, eight parameters of the GPS Klobuchar model, three parameters of the Galileo Ne-Quick model and nine parameters of the BDGIM model are all provided global ionosphere error correction, and the statistics result of the model correction rate is not obviously different, but the latest ionosphere parameters are generally closer to the overall change rule of an actual ionosphere in time and space, so that the ionosphere error model value correction accuracy calculated by using the latest ionosphere parameters in the embodiment of the application is higher.
In one embodiment, for the method comprising steps 2021 and 2022, that is, the first ionospheric error model value Ion is currently calculated simultaneously A (T k ) Second ionospheric error model value Ion B (T k ) And a deviation DeltaIon B-A In the case of the value, step 203 is shown in 2031 in fig. 3, and includes: and correcting the ionospheric errors of the satellites respectively by using the calculated second ionospheric error model value of the satellites or the second ionospheric error model value and the deviation so as to obtain PVT position solutions at the current moment. The specific implementation can be divided into the following two processing modes:
a second ionospheric error model value Ion that can be calculated directly using the latest ionospheric parameters detected B (T k ) To accomplish ionospheric error correction, i.e. Ion in equation (1) i For the current time T k Second ionospheric error model value Ion for the ith satellite B (T k ) i I.e. Ion i ＝Ion B (T k ) i This approach is suitable for scenes where the user is more concerned with the absolute accuracy of the real-time position. At this time, step 203 in this embodiment, like step 2031 in fig. 3, may include:
using the second ionospheric error model value Ion of the ith satellite at the current moment B (T k ) i At the current time T k Ionosphere error correction of the ith satellite is carried out, and the current moment T is calculated in real time through the formula (1) and the formula (2) k PVT position solution X of (2) pvt (T k )。
A method based on the ionosphere error model value Ion via the first ionosphere can be used A (T k ) And a second ionospheric error model value Ion B (T k ) Deviation deltaion of (a) B-A Compensating the second ionospheric error model value Ion B (T k ) The ionospheric error correction is completed by the latter value, namely Ion in formula (1) i Is the deviation delta Ion B-A Compensating the second ionospheric error model value Ion B (T k ) i Post value, i.e. Ion i ＝Ion B (T k ) i -ΔIon B-A This approach is suitable for scenarios where the user is less concerned with the continuity of the position over a short period of time. At this time, step 103 in this embodiment, like step 2031 in fig. 2, may include:
using the deviation delta Ion of the ith satellite at the current moment B-A Compensating the second ionospheric error model value Ion B (T k ) i The current time T is carried out by the post value k Ionosphere error correction of the ith satellite is carried out, and the current moment T is calculated in real time through the formula (1) and the formula (2) k PVT position solution X of (2) pvt (T k )。
Step 204: and calculating the receiver clock difference of each satellite at the current moment according to the first ionospheric error model value.
In one illustrative example, for a current only one set of first ionospheric error model values Ion A (T k ) Step 204 may include:
based on the user position in the PVT position solution, the first ionospheric error model value Ion of the ith satellite A (T k ) i The current time T is calculated by the formula (1) and the formula (2) k First receiver clock error for the ith valid satellite
First receiver clock difference for each satelliteObtaining the current time T after weighted average k First receiver clock difference of next frequency point +.>And taking the first receiver clock difference obtained after weighted averaging as the receiver clock difference of each frequency point at the current moment.
In one embodiment, the first receiver clock bias for each satellite may be calculated according to equation (3)Obtaining the current time T after weighted average k First receiver clock difference of next frequency point +.>
In one embodiment, the present time T is calculated for each satellite's receiver clock difference based on the first ionospheric error model value k Is the first receiver clock difference value dt r Take the value of The calculation of (2) is shown in the formula (3):
in one illustrative example, an effective first ionospheric error model value Ion is calculated for the current time A (T k ) Second ionospheric error model value Ion B (T k ) Step 204, as shown in step 2041 of fig. 3, includes: based on the first ionospheric error model value and the second ionospheric error modelThe value calculates the receiver clock difference for each satellite at the current time.
In one embodiment, step 2041 in fig. 3 may specifically include:
based on the user position in the PVT position solution, the first ionospheric error model value Ion of the ith satellite A (T k ) i Second ionospheric error model value Ion for ith satellite B (T k ) i The current time T is calculated by the formula (1) and the formula (2) k The clock difference of the first receiver of each frequency pointSecond receiver clock error->
First receiver clock difference for each satelliteSecond receiver clock error->Respectively weighted-average to obtain the current time T k First receiver clock difference of next frequency point +.>And a second receiver clock difference
Calculating and storing the clock difference of the first receiver of each frequency point at the current timeClock difference of second receiverIs a clock deviation value Deltadt of (a) r(B-A) As shown in the formula (4),
calculating the current time T k Is the second receiver clock difference obtained after weighted averaging of (a)From the clock offset value Deltadt r(B-A) The difference of the current time T k The receiver clock of each frequency point at the current moment is poor. I.e. the current time T k The receiver clock difference of each satellite is valued as +.>
In one embodiment, the present time T is calculated for each satellite's receiver clock difference at the present time based on the first ionospheric error model value and the second ionospheric error model value k Is the first receiver clock difference value dt r Take the value ofThe calculation of (2) is shown in formula (3); at the present time T k Is Zhong Chazhi dt of (v) r The value is +.>The calculation of (2) is shown in formula (5):
in the formulas (3) and (5), w nA 、w nB Indicating the current time T k And the weight of the nth satellite clock difference is lower. The weight can be obtained by the existing calculation method, and can be generally calculated according to the signal quality of each satellite such as signal to noise ratio, altitude angle, continuous tracking time and pseudoDistance residual, ionospheric model errors, etc., and the specific implementation is not intended to limit the scope of the present application. The reasonable value of the weight can not only effectively inhibit the clock difference burr of the observed quantity of a single satellite, but also obtain the clock difference value of the receiver of each frequency point and the clock deviation value thereof.
Step 205: and providing time service by adopting the calculated receiver clock error value.
In an illustrative example, it may further include: the GNSS receiver clock differences at each subsequent time instant are based on the latest ionosphere Ion set data (B) Ionospheric error correction and compensation for Deltdt r(B-A) Until the next time the new set of ionospheric parameters is resolved to change (i.e., the third ionospheric parameter information Ion is resolved data (c) And with a second ionospheric error model value Ion B (T k ) Parameters are different), and then returns to step 104 to calculate Δdt again according to equation (3), equation (4) and equation (5) r(B-A) The value is updated and used.
In practical application, according to the time service providing method provided by the embodiment of the application, as long as the latest ionized layer parameters are analyzed in real time, after clock bias values of clock errors of two receivers are estimated by utilizing the two groups of ionized layer parameters existing at the same time and the corresponding models, the ionized layer error correction can be carried out and the clock bias is compensated when the latest ionized layer parameters are switched to be used in real time, so that the problem of receiver clock error jump caused by switching the latest parameters is eliminated, the real-time broadcast ionized layer model of each GNSS system is fully utilized, and the improvement of the real-time ionized layer error is guaranteed to be optimal. Furthermore, the method can provide the user with higher-precision, continuous and stable GNSS position and time service without adding additional complex operation amount.
It should be noted that the known user position in step 204 is not limited to the calculated real-time position, and other effective positions with higher accuracy may be used, and the specific implementation is not intended to limit the protection scope of the present invention. Such as: for static scenes, external configuration or input accurate coordinates, fixed coordinates that the receiver autonomously optimizes can be used; and the following steps: for dynamic scenarios, a higher accuracy of the resolved input position may be used, with a more accurate user position ensuring a more stable, accurate receiver clock bias.
According to the time service providing method provided by the embodiment of the application, in the position and time service resolving of the GNSS receiver of the user, the real-time broadcast ionosphere model of each GNSS system is fully utilized, the optimal improvement of the real-time ionosphere error is ensured, and in addition, the GNSS positioning and time service with higher precision, continuity and stability is provided for the user without adding additional complex operation amount, so that the multi-system GNSS satellite positioning is supported. More preferably, when the ionosphere parameters are switched, the deviation caused by the model errors is calculated according to the two groups of parameters before and after the switching, so that the position and clock error jump when the ionosphere errors are changed by different parameters and models is eliminated, and the precision and reliability of the position and clock error are effectively improved.
The present application also provides a computer-readable storage medium storing computer-executable instructions for performing the time service providing method of any one of the above.
The application further provides a time service providing device, which comprises a memory and a processor, wherein the memory stores the following instructions executable by the processor: a step for executing the time service providing method according to any one of the above.
Fig. 3 is a schematic structural diagram of a time service providing device according to an embodiment of the present application, where, as shown in fig. 3, at least the time service providing device includes: an acquisition unit and a processing unit, wherein,
the acquisition unit is used for determining a first ionospheric error model value of each satellite corresponding to the latest set of first ionospheric parameter information stored at the current moment and determining a second ionospheric error model value of each satellite corresponding to the second ionospheric parameter information obtained by analysis at the current moment;
and the processing unit is used for providing time service by using the first ionosphere error model value and the second ionosphere error model value.
In one illustrative example, the second ionospheric parameter information is different from the first ionospheric parameter information.
In an exemplary embodiment, the acquisition unit is further configured to: acquiring a user observation value of a GNSS receiver at the current moment;
the apparatus may further include: an ionosphere parameter acquisition unit and an ionosphere error acquisition unit; wherein,
the ionosphere parameter acquisition unit is used for analyzing second ionosphere parameter information at the current moment;
the ionosphere error acquisition unit is used for calculating a first ionosphere error model value/a second ionosphere error model value of each satellite at the current moment according to the acquired user observation value at the current moment and the first ionosphere parameter information/the second ionosphere parameter information; and calculating the deviation of the first ionospheric error model value and the second ionospheric error model value of each satellite.
In an exemplary embodiment, the time service providing apparatus of the present application may further include: the PVT position solution obtaining unit is used for correcting the ionospheric errors of the satellites respectively by using the calculated second ionospheric error model value of the satellites or the deviation between the second ionospheric error model value and the first ionospheric error model value and the second ionospheric error model value so as to obtain PVT position solutions at the current moment.
In one embodiment, the PVT location solution acquisition unit may be configured to:
by the current time T k First ionospheric error model value Ion for the ith satellite A (T k ) i At the current time T k Ionosphere error correction of the ith satellite is carried out, and the current moment T is calculated in real time through the formula (1) and the formula (2) k PVT position solution X of (2) pvt (T k )。
In one embodiment, the clock difference acquisition unit may be configured to:
based on the user position in the PVT position solution, the first ionospheric error model value Ion of the ith satellite A (T k ) i The current time T is calculated by the formula (1) and the formula (2) k First receiver clock error for the ith satellite
First receiver clock difference for each satelliteObtaining the current time T after weighted average k First receiver clock difference of next frequency point +.>And taking the first receiver clock difference obtained after weighted averaging as the receiver clock difference of each frequency point at the current time.
In one embodiment, the PVT position solution acquisition unit is specifically configured to:
using the second ionospheric error model value Ion of the ith satellite at the current moment B (T k ) i At the current time T k Ionosphere error correction of the ith satellite is carried out, and the current moment T is calculated in real time through the formula (1) and the formula (2) k PVT position solution X of (2) pvt (T k )。
In one embodiment, the PVT position solution acquisition unit is specifically configured to:
using the deviation delta Ion of the ith satellite at the current moment B-A Compensating the second ionospheric error model value Ion B (T k ) i The current time T is carried out by the post value k Ionosphere error correction of the ith satellite is carried out, and the current moment T is calculated in real time through the formula (1) and the formula (2) k PVT position solution X of (2) pvt (T k )。
In an exemplary embodiment, the time service providing apparatus of the present application may further include: and the clock difference acquisition unit is used for calculating the receiver clock difference of each satellite at the current moment according to the first ionosphere error model value.
And the processing unit is used for providing time service by adopting the calculated receiver clock error value.
In one embodiment, the clock difference acquisition unit may be configured to:
according to PVT bitsUser position in solution, first ionospheric error model value Ion of ith satellite A (T k ) i Second ionospheric error model value Ion for ith satellite B (T k ) i The current time T is calculated by the formula (1) and the formula (2) k First receiver clock error for the ith satelliteSecond receiver clock error->
First receiver clock difference for each satelliteSecond receiver clock error->Respectively weighted-average to obtain the current time T k First receiver clock difference of next frequency point +.>And a first receiver clock difference
Calculating and saving the weighted average of the first receiver clock differencesSecond receiver clock error->Is a clock deviation value Deltadt of (a) r(B-A) ；
Calculating the current time T k Is the second receiver clock difference obtained after weighted averaging of (a)Deviation from clockValue Deltdt r(B-A) The difference of the current time T k The receiver clock of each frequency point at the current moment is poor.
In the time service providing device provided by the embodiment of the application, in the position and time service resolving of the GNSS receiver of the user, the real-time broadcast ionosphere model of each GNSS system is fully utilized, the improvement and the optimization of the real-time ionosphere error are ensured, and in addition, the GNSS positioning and time service with higher precision, continuity and stability is provided for the user without adding additional complex operation amount, so that the multi-system GNSS satellite positioning is supported.
More preferably, when the ionosphere parameters are switched, the deviation caused by the model errors is calculated according to the two groups of parameters before and after the switching, so that the position and clock error jump when the ionosphere errors are changed by different parameters and models is eliminated, and the precision and reliability of the position and clock error are effectively improved.
Although the embodiments disclosed in the present application are described above, the embodiments are only used for facilitating understanding of the present application, and are not intended to limit the present application. Any person skilled in the art to which this application pertains will be able to make any modifications and variations in form and detail of implementation without departing from the spirit and scope of the disclosure, but the scope of the application is still subject to the scope of the claims appended hereto.

Claims (10)

1. A time service providing method, comprising:
determining a first ionospheric error model value of each satellite corresponding to the stored first ionospheric parameter information at the current moment, and determining a second ionospheric error model value of each satellite corresponding to the second ionospheric parameter information obtained by analyzing at the current moment;
and providing time service by using the first ionosphere error model value and the second ionosphere error model value.
2. The time service providing method according to claim 1, wherein the first ionospheric error model value or the second ionospheric error model value is determined by:
acquiring a user observation value of the GNSS receiver of the satellite navigation positioning system at the current moment;
calculating to obtain the first ionosphere error model value according to the obtained user observation value at the current moment and the first ionosphere parameter information; or calculating the second ionospheric error model value according to the obtained user observation value at the current moment and the second ionospheric parameter information.
3. The time service providing method according to claim 2, wherein the providing the time service using the first ionospheric error model value and the second ionospheric error model value comprises:
calculating the receiver clock difference of each satellite at the current moment according to the user observation value, the first ionospheric error model value and the second ionospheric error model value;
and providing time service by adopting the calculated receiver clock error value.
4. The time service providing method according to claim 1, wherein the providing the time service using the first ionospheric error model value and the second ionospheric error model value comprises:
calculating the receiver clock difference of each satellite at the current moment according to the PVT position solution at the current moment, the first ionosphere error model value and the second ionosphere error model value;
and providing time service by adopting the calculated receiver clock error value.
5. The time service providing method according to claim 4, wherein the PVT position solution at the current time is obtained according to the following steps:
correcting the ionospheric error of each satellite by using the second ionospheric error model value of each satellite to obtain PVT position solution at the current moment;
or,
calculating the deviation of the first ionospheric error model value and the second ionospheric error model value of each satellite; and correcting the ionosphere error of each satellite by using the second ionosphere error model value and the deviation to obtain PVT position solution at the current moment.
6. The time service providing method according to claim 4, wherein the calculating the receiver clock differences of each satellite at the current time according to the PVT position solution at the current time, the first ionospheric error model value, and the second ionospheric error model value comprises:
according to the user position in the PVT position solution, the first ionospheric error model value of the ith satellite and the second ionospheric error model value of the ith satellite, respectively calculating the first receiver clock difference and the second receiver clock difference of each frequency point at the current moment;
respectively carrying out weighted average on the first receiver clock difference and the second receiver clock difference of each satellite to obtain the first receiver clock difference and the second receiver clock difference of each frequency point at the current time, and calculating clock deviation values of the first receiver clock difference and the second receiver clock difference of each frequency point at the current time;
and calculating the difference value between the second receiver clock difference obtained after the weighted average of the current moment and the clock deviation value as the receiver clock difference of each frequency point at the current moment.
7. The time service providing method according to claim 6, wherein the current time T is calculated by the following formula k First receiver clock difference or second receiver clock difference of the ith satellite:
P i ＝R i +Ion i wherein P is i Pseudo-range observables of an ith satellite are represented; ion (Ion) i A first ionospheric error model value or a second ionospheric error model value representing an ith satellite; r is R i A theoretical distance value representing the ith satellite including various errors other than the ionospheric error term;
wherein R is i Expressed as:r i representing the geometric distance between the satellite position of the ith satellite and the receiver; c represents the speed of light; />Representing the first receiver clock difference or the second receiver clock difference calculated by the ith satellite pseudo-range; />The satellite end clock difference of the ith satellite is represented; tgd i Group delay representing the ith satellite; trop (Trop) i A tropospheric delay representing an ith satellite; epsilon i And the pseudo-range observation noise of the ith satellite is represented.
8. The time service providing method according to claim 6, further comprising:
and (3) carrying out ionospheric error correction on the receiver clock differences at the subsequent moments based on the latest ionospheric parameters, compensating the deviation, returning to the step of calculating the receiver clock differences of each satellite at the current moment according to the first ionospheric error model value and the second ionospheric error model value after next analysis to a changed set of latest ionospheric parameters, and updating the clock deviation value.
9. A computer-readable storage medium storing computer-executable instructions for performing the time service providing method of any one of claims 1 to 8.
10. A time service providing apparatus comprising a memory and a processor, wherein the memory stores instructions executable by the processor to: steps for performing the time service providing method of any one of claims 1 to 8.
CN202311640271.9A 2023-12-01 2023-12-01 Time service providing method and device Pending CN117826568A (en)

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Application Number Priority Date Filing Date Title
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