CN117471500B - Beidou satellite-based high-precision time service method and device considering time-varying offset of receiver - Google Patents
Beidou satellite-based high-precision time service method and device considering time-varying offset of receiver Download PDFInfo
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- 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
- G01S19/23—Testing, monitoring, correcting or calibrating of receiver elements
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- 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
- G01S19/23—Testing, monitoring, correcting or calibrating of receiver elements
- G01S19/235—Calibration of receiver components
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- 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
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- 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
- G01S19/258—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 the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
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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
- G04R20/04—Tuning or receiving; Circuits therefor
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
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Abstract
The invention provides a Beidou satellite-based high-precision time service method and device taking time variation deviation of a receiver into consideration, which utilize observation data and broadcast data to carry out precision data recovery to obtain real-time precision orbit and real-time precision satellite clock error of a Beidou satellite; then establishing a PPP time service model taking the time variation deviation of the receiver into consideration, and outputting the receiver clock difference of the current epoch by utilizing the PPP time service model; detecting the abnormality of the receiver clock difference of the current epoch, and finally outputting the receiver clock difference of the current epoch; and (3) regulating and controlling the crystal oscillator in real time by using a clock control method, and inputting signals output by the crystal oscillator to a receiver so that the receiver outputs UTC time and 1PPS signals. Compared with the prior art, the invention not only can make PPP engineering possible without depending on a network, but also can adapt to different temperature environments, and improves the reliability and continuity of real-time PPP time service.
Description
Technical Field
The invention belongs to the technical field of navigation satellite time service, and particularly relates to a Beidou satellite-based high-precision time service method and device considering time variation deviation of a receiver.
Background
As one of the important applications of GNSS, the conventional satellite unidirectional time service precision is about 20-50 ns. With the rapid development of technology, the conventional satellite time service method has been difficult to meet the requirements of society, economy and technology development, so that students further explore a time service method with higher precision, and the precise single point positioning (PPP) time service method can realize sub-nanosecond time service without depending on a reference station, and at present, the PPP time transfer technology has been used for international UTC/TAI comparison.
Along with the demand of people for real-time performance, the post-PPP time service cannot be widely applied, so that the real-time PPP time service method is favored by students gradually, the real-time PPP transmits precise orbit and clock products through a network, and then the PPP algorithm is used for resolving, and finally the high-precision positioning/time service and other applications are realized. The domestic scholars or team reduce the standard of the real-time product to UTC (k), and broadcast the standard to users through the network, and the users realize high-precision time service through PPP algorithm after receiving the real-time track and the clock error product.
However, the real-time PPP timing needs to rely on a network, and because of the instability of the network, the PPP is easy to re-converge or unavailable, which makes it difficult to ensure the reliability of the PPP timing, greatly limits the popularization of the application of PPP timing, and as shown in fig. 1, the receiver clock error is interrupted or re-converged after the network is interrupted. In addition, unlike a time keeping laboratory, the time service receiver can prevent from approaching to a constant temperature environment, and common public users generally have difficulty in guaranteeing the constant temperature environment of the time service receiver, and the change of temperature can have a great influence on the pseudo-range deviation of the receiver, so that the time service performance is reduced.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a Beidou satellite-based high-precision time service method and device considering time variation deviation of a receiver. The technical problems to be solved by the invention are realized by the following technical scheme:
in a first aspect, the invention provides a Beidou satellite-based high-precision time service method considering time variation deviation of a receiver, which comprises the following steps:
S100, receiving observation data obtained by observing a Beidou satellite and broadcast data of the Beidou satellite in real time through a receiver; the broadcast data comprises broadcast ephemeris and PPP-B2B correction;
S200, performing precise data recovery by using the observation data and the broadcast data to obtain a real-time precise orbit and a real-time precise satellite clock error of the Beidou satellite;
s300, establishing a PPP time service model considering time-varying deviation of a receiver according to the real-time precise orbit and the real-time precise satellite clock difference;
s400, outputting the receiver clock difference of the current epoch by using the PPP timing model;
s500, detecting abnormality of the receiver clock difference of the current epoch, and outputting the receiver clock difference of the current epoch if the abnormality does not exist; if abnormal, the receiver clock difference of the current epoch is obtained by utilizing the receiver clock difference fitting of the history epoch, and the current epoch is output;
And S600, performing real-time regulation and control on the crystal oscillator by using a clock control method, and inputting signals output by the crystal oscillator to a receiver, so that the receiver outputs UTC time and 1PPS signals according to the receiver clock difference of the current epoch.
In a second aspect, the invention provides a Beidou satellite-based high-precision time service device considering time variation deviation of a receiver, which is applied to the receiver, and the Beidou satellite-based high-precision time service device considering the time variation deviation of the receiver executes the following processes:
s100, receiving observation data obtained by observing a Beidou satellite in real time and broadcasting data of the Beidou satellite; the broadcast data comprises broadcast ephemeris and PPP-B2B correction;
s200, performing precise data recovery by using the observation data and the broadcast data to obtain a real-time precise orbit and a real-time precise satellite clock error of the Beidou satellite;
s300, establishing a PPP time service model considering time-varying deviation of a receiver according to the real-time precise orbit and the real-time precise satellite clock difference;
s400, outputting the receiver clock difference of the current epoch by using the PPP timing model;
S500, carrying out abnormality detection on the receiver clock difference of the current epoch, and if the receiver clock difference is abnormal, fitting the receiver clock difference of the current epoch by using the receiver clock difference of the history epoch; outputting the receiver clock difference of the current epoch if no abnormality exists;
And S600, performing real-time regulation and control on the crystal oscillator by using a clock control method, and inputting signals output by the crystal oscillator to a receiver, so that the receiver outputs UTC time and 1PPS signals according to the receiver clock difference of the current epoch.
The beneficial effects are that:
The invention provides a Beidou satellite-based high-precision time service method and device taking time variation deviation of a receiver into consideration, which utilize observation data and broadcast data to carry out precision data recovery to obtain real-time precision orbit and real-time precision satellite clock error of a Beidou satellite; then establishing a PPP time service model taking the time variation deviation of the receiver into consideration, and outputting the receiver clock difference of the current epoch by utilizing the PPP time service model; detecting the abnormality of the receiver clock difference of the current epoch, and finally outputting the receiver clock difference of the current epoch; and (3) carrying out real-time regulation and control on the crystal oscillator by using a clock control method, and inputting signals output by the crystal oscillator into a receiver, so that the receiver outputs UTC time and 1PPS signals according to the receiver clock difference after the real-time regulation and control. Compared with the prior art, the invention not only makes the PPP engineering possible without depending on the network, but also adapts to different temperature environments, and improves the reliability and continuity of the real-time PPP time service.
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Drawings
FIG. 1 is a diagram of a receiver clock correction based on network transmission real-time precision orbit and clock correction, calculated using PPP;
FIG. 2 is a schematic flow chart of a Beidou satellite-based high-precision time service method considering time-varying offset of a receiver;
FIG. 3 is a schematic diagram of the Beidou satellite-based timing principle taking into account receiver time-varying offset;
FIG. 4 is a schematic diagram of a receiver clock skew sequence for BDS-3PPP resolution based on PPP-B2B;
fig. 5 is a diagram of a conventional PPP model and corrected vlan variance accounting for receiver time-varying bias PPP model solutions.
Detailed Description
The present invention will be described in further detail with reference to specific examples, but embodiments of the present invention are not limited thereto.
With reference to fig. 2 to 5, the invention provides a Beidou satellite-based high-precision time service method considering time variation deviation of a receiver, which comprises the following steps:
S100, receiving observation data obtained by observing a Beidou satellite and broadcast data of the Beidou satellite in real time through a receiver; the broadcast data comprises broadcast ephemeris and PPP-B2B correction;
referring to fig. 3, the present invention receives the observation data, broadcast ephemeris and PPP-B2B correction of the beidou satellite in real time through a GNSS module on the receiver.
S200, performing precise data recovery by using the observation data and the broadcast data to obtain a real-time precise orbit and a real-time precise satellite clock error of the Beidou satellite;
in a specific embodiment of the present invention, S200 includes:
S210, decoding the observation data and the broadcast ephemeris to obtain an observation value of the Beidou satellite and decoded broadcast ephemeris;
S220, combining the decoded broadcast ephemeris and the PPP-B2B correction to generate a real-time precise orbit and a real-time precise satellite clock error of the Beidou satellite.
The real-time precision orbit in S220 is represented as:
wherein X pre is a real-time precise orbit, and X brd is an orbit calculated based on broadcast ephemeris; (e r,ea,ec) is a conversion matrix; ΔO is the correction vector of PPP-B2B in radial, normal and tangential directions; r is the satellite position; The satellite speed [ delta O r,ΔOa,ΔOc ] is the correction of the real-time precise orbit in the radial direction, the normal direction and the tangential direction;
The real-time precise satellite clock difference in S220 is expressed as:
Wherein dt s is the real-time precision satellite clock difference, The satellite clock correction calculated for the broadcast ephemeris, deltat is the satellite clock correction in PPP-B2B service and c is the speed of light.
The invention then decodes the observed data and broadcast ephemeris; and combining the broadcast ephemeris and the PPP-B2B correction to generate a real-time precise orbit and a real-time precise satellite clock error.
S300, establishing a PPP time service model considering time-varying deviation of a receiver according to the real-time precise orbit and the real-time precise satellite clock difference;
in a specific embodiment of the present invention, S300 includes:
S310, constructing an observation equation according to the real-time precise orbit, the real-time precise satellite clock difference and the observation value;
Compared with the traditional ionosphere-free combined PPP, the non-combined observation value is directly used herein, the noise of the non-combined observation value is smaller, pseudo-range and carrier non-combined observation equations are listed, taking B1I and B3I of a Beidou No. three satellite as an example, and the observation equation in S310 is expressed as:
wherein, parameters carrying corner marks B1I and B3I represent parameters of Beidou satellites B1I and B3I; and/> Non-combined pseudo-moment observations of the Beidou satellite B1I and the Beidou satellite B3I respectively; /(I)The geometric distance between the Beidou satellite S and the receiver r is the geometric distance between the Beidou satellite S and the receiver r; δt r and δt s are respectively the receiver clock difference and the real-time precise satellite clock difference; d r,B1I and/>The delay is respectively the hardware delay of a receiver and a satellite terminal on a B1I frequency point; d r,B3I and/>The delay is respectively the hardware delay of a receiver and a satellite terminal on a B3I frequency point; /(I)Is a troposphere; /(I)Is an ionosphere; /(I)And/>Pseudo-range observation noise for the bucket satellites B1I and B3I, respectively; /(I)And/>The primary carrier observation values of the Beidou satellite B1I and the Beidou satellite B3I are respectively; gamma is the ionospheric coefficient; lambda B1I and lambda B3I are the wavelengths of the frequency points of Beidou satellites B1I and B3I respectively; /(I)And/>Ambiguity on the frequency points of the Beidou satellites B1I and B3I respectively; b r,B1I and B r,B3I are the carrier delays of the Beidou satellites B1I and B3I to the receiver, respectively; /(I)And/>Carrier delays of the Beidou satellites B1I and B3I respectively;
and/> Carrier phase observation noise for the bucket satellites B1I and B3I, respectively;
S320, redefining the real-time precise satellite clock difference and the receiver clock difference, and establishing a time service model by combining the observation equation;
Since the reference frequency point of the BDS-3 satellite clock in the PPP-B2B product is B3I, the satellite clock skew will absorb the hardware delay at the B3I frequency point. For the receiver, the receiver clock difference will absorb the receiver-side hardware delay on the B1I and B3I frequency points, and therefore, redefined receiver clock difference and real-time precision satellite clock difference are expressed as:
wherein, Receiver clock skew for redefined; /(I)Real-time precision satellite clock error for redefined; /(I)AndAll absorb ionosphere-free combined hardware delays; d IF is the receiver hardware delay; f B1I is the frequency of the frequency point of the Beidou satellite B1I; f B3I is the frequency of the B3I frequency point of the Beidou satellite;
S330, correcting errors of the time service model in S320, which are caused by troposphere errors, phase winding, antenna phase center changes and relativistic effects, to obtain an error corrected time service model;
bringing equation (5) into equation (3) and equation (4) yields a time service model expressed as:
Wherein DCB r,B1I/B3I is the inter-code bias of the receiver, DCB B s 1I/B3I is the inter-code bias of the satellite,
S340, carrying out parameter estimation on the time service model subjected to error correction in S330 to obtain a time service model subjected to parameter estimation;
in a specific embodiment of the present invention, S340 includes:
Constant estimation is carried out on the coordinates and the ambiguity of the receiver;
estimating the wet component of the troposphere by adopting a random walk parameter;
and (3) performing parameter estimation on the ionosphere and the receiver clock error by adopting white noise to realize parameter estimation on the time service model after error correction in S330.
The invention corrects tropospheric errors, phase winding, antenna phase center variations, relativistic effects, and the like. And then, carrying out parameter estimation by utilizing Kalman filtering, mainly focusing on receiver clock error parameters, taking receiver coordinate parameters as static estimation, taking ambiguity as constant estimation, estimating the wet component of the troposphere by adopting random walk parameters, carrying out parameter estimation by adopting white noise on the ionosphere, and giving time results shown in figure 4.
S350, converting the time service model of the parameter estimation in S340 through hardware delay classification of receiver clock error, thereby establishing a PPP time service model considering receiver time variation deviation.
In a specific embodiment of the present invention, to further design a beidou satellite-based time service model that considers a receiver time variation bias, S350 includes:
S351, dividing the hardware delay of the receiver clock error into a constant part and a time-varying part, estimating the time-varying part by using a converged Kalman filtering algorithm and estimating the constant part by using a random walk model, and obtaining a conversion expression of the receiver clock error:
wherein, Time varying bias for the receiver;
The invention does not estimate the time-varying deviation of the receiver in the beginning stage of the kalman filtering, and the receiver clock error in the beginning stage is estimated by adopting a white noise model, namely the receiver clock error estimation in S340. After kalman filtering convergence, starting to estimate the time-varying deviation of the receiver, wherein the condition of the filtering convergence is that the precision of three-dimensional coordinate parameters is better than 0.1 meter, and the receiver clock error is considered to be converged; once the receiver clock error convergence is completed, the invention starts to estimate the receiver time-varying bias, and at this time, the receiver clock error parameters are estimated by adopting a random walk model, and the noise variance q w of the random walk model is expressed as:
delta Allan is the Arrhenius variance corresponding to the sampling interval of the receiver clock error; τ ctrl is the sampling interval;
s352, substituting the conversion expression of the receiver clock difference into the time service model of the parameter estimation in S340 to obtain a PPP time service model considering the receiver time variation deviation:
wherein, For ambiguity parameters of absorption phase delay on B1I frequency point of Beidou satellite,/>The ambiguity parameters of the absorption phase delay on the B3I frequency point of the Beidou satellite are obtained.
Compared with the traditional non-combined PPP time service model, the PPP time service model which considers the time variation deviation of the receiver is added with one parameter. Fig. 5 is a schematic diagram of calculating frequency stability by using PPP time service model to calculate clock difference, and fig. 5 shows frequency stability calculated by conventional model and frequency stability of time-varying deviation of receiver estimated by the present invention. In fig. 5, the first scheme is the frequency stability calculated by the conventional model, and the second scheme is the frequency stability of the receiver time-varying deviation estimation method. It can be seen from fig. 5 that the frequency stability calculated by the PPP time service model estimating the receiver time-varying offset is better.
S400, outputting the receiver clock difference of the current epoch by using the PPP timing model;
s500, detecting abnormality of the receiver clock difference of the current epoch, and outputting the receiver clock difference of the current epoch if the abnormality does not exist; if abnormal, the receiver clock difference of the current epoch is obtained by utilizing the receiver clock difference fitting of the history epoch, and the current epoch is output;
in a specific embodiment of the present invention, S500 includes:
s510, storing the receiver clock difference in a sliding window form;
The invention can use the receiver to detect the device to finish the abnormality detection in practice, the device does not provide time information for the first seconds after the device is started, the time information is provided for the user after 10 seconds, and the clock difference of the receiver is stored 10 seconds after the device is started.
S520, using sliding window to detect the middle coarse difference of the receiver clock difference of the current epoch,
To determine whether an anomaly has occurred;
S530, if abnormality occurs, performing first-order quadratic term fitting by using the receiver clock difference of the historical epoch so as to predict the receiver clock difference of the current epoch;
S540, if no abnormality occurs, the receiver clock difference of the current epoch is stored in a storage structure of the sliding window, and the receiver clock difference of the current epoch is output.
And S600, performing real-time regulation and control on the crystal oscillator by using a clock control method, and inputting signals output by the crystal oscillator to a receiver, so that the receiver outputs UTC time and 1PPS signals according to the receiver clock difference of the current epoch. In a specific embodiment of the present invention, S600 includes:
s610, performing taming on an atomic clock or a crystal oscillator by using a time discrete type secondary regulator to obtain a tamed crystal oscillator;
wherein, the discipline formula is:
wherein, Is the clock state at time k+1,/>The clock state at the k moment comprises a precise satellite real-time clock difference delta t r and a clock drift df, A is a coefficient, tau ctrl is a sampling interval, B is a coefficient for adjusting delta t r, and u k is a clock control input parameter.
S620, inputting the 10MHz signal output by the tamed crystal oscillator into the receiver, so that the receiver outputs UTC time and 1PPS according to the receiver clock difference of the current epoch.
The invention can utilize the tamed crystal oscillator or atomic clock to send out clock signals with the frequency of 10MHz, and input the clock signals into the receiver, and the receiver outputs UTC time and 1PPS signals under the action of the clock signals. The information required for time service is UTC and pulse per second (1 PPS), so time service can be completed according to the two information.
The invention provides a Beidou satellite-based high-precision time service device considering time variation deviation of a receiver, which is applied to the receiver, and the Beidou satellite-based high-precision time service device considering the time variation deviation of the receiver executes the following processes:
s100, receiving observation data obtained by observing a Beidou satellite in real time and broadcasting data of the Beidou satellite; the broadcast data comprises broadcast ephemeris and PPP-B2B correction;
S200, performing precise data recovery by using the observation data and the broadcast data to obtain a real-time precise orbit and a real-time precise satellite clock error of the Beidou satellite;
s300, establishing a PPP time service model considering time-varying deviation of a receiver according to the real-time precise orbit and the real-time precise satellite clock difference;
s400, outputting the receiver clock difference of the current epoch by using the PPP timing model;
S500, carrying out abnormality detection on the receiver clock difference of the current epoch, and if the receiver clock difference is abnormal, fitting the receiver clock difference of the current epoch by using the receiver clock difference of the history epoch; outputting the receiver clock difference of the current epoch if no abnormality exists;
And S600, performing real-time regulation and control on the crystal oscillator by using a clock control method, and inputting signals output by the crystal oscillator to a receiver, so that the receiver outputs UTC time and 1PPS signals according to the receiver clock difference of the current epoch.
The invention directly transmits the correction through the Beidou No. three satellite, so that the real-time PPP timing does not depend on a network any more, and the invention provides possibility for PPP timing engineering, and simultaneously, the invention considers the time-varying characteristics of the receiver hardware, solves the problem of time-varying precision reduction caused by the change of the hardware time delay caused by different temperature environments, and improves the reliability and the continuity of the real-time PPP timing.
Aiming at the problems that the current real-time precise single point positioning (PPP) time service method is mostly based on network transmission correction, the receiver clock error is easy to re-converge due to unstable network in the actual application process, and the reliability of time service precision is difficult to guarantee, and the conventional PPP time service method is mostly to take the receiver pseudo range deviation as constant estimation, so that the PPP time service performance is reduced, the invention provides a Beidou satellite-based high-precision time service method and device which take the receiver time variation deviation into consideration, and aims at the problem of time service precision reduction caused by the change of receiver end code deviation caused by different temperatures, and the real-time precise orbit and real-time precise satellite clock error of a Beidou satellite are obtained by performing precise data recovery by using observation data and broadcast data; then establishing a PPP time service model taking the time variation deviation of the receiver into consideration, and outputting the receiver clock difference of the current epoch by utilizing the PPP time service model; detecting the abnormality of the receiver clock difference of the current epoch, and finally outputting the receiver clock difference of the current epoch; and (3) performing real-time regulation and control on the crystal oscillator by using a clock control method, and inputting signals output by the crystal oscillator to a receiver, so that the receiver outputs UTC time and 1PPS signals according to the real-time regulation and control. Compared with the prior art, the invention not only makes the PPP engineering possible without depending on the network, but also adapts to different temperature environments, and improves the reliability and continuity of the real-time PPP time service.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.
Claims (10)
1. A Beidou satellite-based high-precision time service method considering time variation deviation of a receiver is characterized by comprising the following steps:
S100, receiving observation data obtained by observing a Beidou satellite and broadcast data of the Beidou satellite in real time through a receiver; the broadcast data comprises broadcast ephemeris and PPP-B2B correction;
s200, performing precise data recovery by using the observation data and the broadcast data to obtain a real-time precise orbit and a real-time precise satellite clock error of the Beidou satellite;
s300, establishing a PPP time service model considering time-varying deviation of a receiver according to the real-time precise orbit and the real-time precise satellite clock difference;
s400, outputting the receiver clock difference of the current epoch by using the PPP timing model;
s500, detecting abnormality of the receiver clock difference of the current epoch, and outputting the receiver clock difference of the current epoch if the abnormality does not exist; if abnormal, the receiver clock difference of the current epoch is obtained by utilizing the receiver clock difference fitting of the history epoch, and the current epoch is output;
And S600, performing real-time regulation and control on the crystal oscillator by using a clock control method, and inputting signals output by the crystal oscillator to a receiver, so that the receiver outputs UTC time and 1PPS signals according to the receiver clock difference of the current epoch.
2. The beidou satellite-based high-precision time service method taking into account time-varying offset of a receiver as set forth in claim 1, wherein S200 includes:
s210, decoding the observation data and the broadcast ephemeris to obtain an observation value of the Beidou satellite and decoded broadcast ephemeris;
S220, combining the decoded broadcast ephemeris and the PPP-B2B correction to generate a real-time precise orbit and a real-time precise satellite clock error of the Beidou satellite.
3. The beidou satellite-based high-precision time service method taking into account time-varying offset of a receiver according to claim 2, wherein the real-time precision orbit in S220 is expressed as:
wherein X pre is a real-time precise orbit, and X brd is an orbit calculated based on broadcast ephemeris; (e r,ea,ec) is a conversion matrix; ΔO is the correction vector of PPP-B2B in radial, normal and tangential directions; r is the satellite position; The satellite speed [ delta O r,ΔOa,ΔOc ] is the correction of the real-time precise orbit in the radial direction, the normal direction and the tangential direction;
The real-time precise satellite clock difference in S220 is expressed as:
Wherein δt s is the real-time precise satellite clock difference, The satellite clock correction calculated for the broadcast ephemeris, deltat is the satellite clock correction in PPP-B2B service and c is the speed of light.
4. The beidou satellite-based high-precision time service method taking into account time-varying offset of receiver according to claim 3, wherein S300 comprises:
S310, constructing an observation equation according to the real-time precise orbit, the real-time precise satellite clock difference and the observation value;
S320, redefining the real-time precise satellite clock difference and the receiver clock difference, and establishing a time service model by combining the observation equation;
S330, correcting errors of the time service model in S320, which are caused by troposphere errors, phase winding, antenna phase center changes and relativistic effects, to obtain an error corrected time service model;
s340, carrying out parameter estimation on the time service model subjected to error correction in S330 to obtain a time service model subjected to parameter estimation;
s350, converting the time service model of the parameter estimation in S340 through hardware delay classification of receiver clock error, thereby establishing a PPP time service model considering receiver time variation deviation.
5. The beidou satellite-based high-precision time service method taking into account time-varying offset of a receiver according to claim 4, wherein the observation equation in S310 is expressed as:
wherein, parameters carrying corner marks B1I and B3I represent parameters of Beidou satellites B1I and B3I;
And Non-combined pseudo-moment observations of the Beidou satellite B1I and the Beidou satellite B3I respectively; /(I)The geometric distance between the Beidou satellite S and the receiver r is the geometric distance between the Beidou satellite S and the receiver r; δt r and δt s are respectively the receiver clock difference and the real-time precise satellite clock difference; d r,B1I and/>The delay is respectively the hardware delay of a receiver and a satellite terminal on a B1I frequency point; d r,B3I and/>The delay is respectively the hardware delay of a receiver and a satellite terminal on a B3I frequency point; /(I)Is a troposphere; /(I)Is an ionosphere; /(I)And/>Pseudo-range observation noise for the bucket satellites B1I and B3I, respectively; and/>
The primary carrier observation values of the Beidou satellite B1I and the Beidou satellite B3I are respectively; gamma is the ionospheric coefficient;
Lambda B1I and lambda B3I are the wavelengths of the frequency points of Beidou satellites B1I and B3I respectively; and/> Ambiguity on the frequency points of the Beidou satellites B1I and B3I respectively; b r,B1I and B r,B3I are the carrier delays of the Beidou satellites B1I and B3I to the receiver, respectively; /(I)And/>Carrier delays of the Beidou satellites B1I and B3I respectively;
and/> Carrier phase observation noise for the bucket satellites B1I and B3I, respectively;
redefined receiver clock differences and real-time precision satellite clock differences are expressed as:
wherein, Receiver clock skew for redefined; /(I)For redefined precision satellite real time clock bias,/>And/>All absorb ionosphere-free combined hardware delays; d IF is the receiver hardware delay; f B1I is the frequency of the frequency point of the Beidou satellite B1I; f B3I is the frequency of the B3I frequency point of the Beidou satellite;
the time service model in S320 is expressed as:
wherein DCB r,B1I/B3I is the inter-code offset of the receiver, As the inter-code bias of the satellite,
6. The beidou satellite-based high-precision time service method taking into account receiver time-varying offset according to claim 5, wherein S340 comprises:
Constant estimation is carried out on the coordinates and the ambiguity of the receiver;
estimating the wet component of the troposphere by adopting a random walk parameter;
and (3) carrying out parameter estimation on the ionosphere and the receiver clock error by adopting white noise, and realizing parameter estimation on the time service model after error correction in S330.
7. The beidou satellite-based high-precision time service method taking into account receiver time-varying offset according to claim 6, wherein S350 comprises:
S351, dividing the hardware delay of the receiver clock error into a constant part and a time-varying part, estimating the time-varying part by using a converged Kalman filtering algorithm and estimating the constant part by using a random walk model, and obtaining a conversion expression of the receiver clock error:
wherein, Time varying bias for the receiver;
The noise variance q w of the random walk model is expressed as:
qw＝(δAllan·τctrl·c)2 (9)；
delta Allan is the Arrhenius variance corresponding to the sampling interval of the receiver clock error; τ ctrl is the sampling interval;
s352, substituting the conversion expression of the receiver clock difference into the time service model of the parameter estimation in S340 to obtain a PPP time service model considering the receiver time variation deviation:
wherein, For ambiguity parameters of absorption phase delay on B1I frequency point of Beidou satellite,/>The ambiguity parameters of the absorption phase delay on the B3I frequency point of the Beidou satellite are obtained.
8. The beidou satellite-based high-precision time service method taking into account time-varying offset of a receiver as set forth in claim 7, wherein S500 includes:
s510, storing the receiver clock difference in a sliding window form;
S520, detecting the receiver clock difference of the current epoch by utilizing the sliding window to determine whether an abnormality occurs;
S530, if abnormality occurs, performing first-order quadratic term fitting by using the receiver clock difference of the historical epoch so as to predict the receiver clock difference of the current epoch;
S540, if no abnormality occurs, the receiver clock difference of the current epoch is stored in a storage structure of the sliding window, and the receiver clock difference of the current epoch is output.
9. The beidou satellite-based high-precision time service method taking into account time-varying offset of a receiver as set forth in claim 7, wherein S600 includes:
s610, performing taming on an atomic clock or a crystal oscillator by using a time discrete type secondary regulator to obtain a tamed crystal oscillator;
wherein, the discipline formula is:
wherein, Is the clock state at time k+1,/>The clock state is the clock state of k time and comprises real-time precise satellite clock difference delta t r and clock drift df, A is a coefficient, B is a coefficient for adjusting delta t r, and u k is a clock control input parameter;
s620, inputting the 10MHz signal output by the tamed crystal oscillator into the receiver, so that the receiver outputs UTC time and 1PPS according to the receiver clock difference of the current epoch.
10. The Beidou satellite-based high-precision time service device considering the time variation deviation of the receiver is characterized by being applied to the receiver, and executing the following processes:
s100, receiving observation data obtained by observing a Beidou satellite in real time and broadcasting data of the Beidou satellite; the broadcast data comprises broadcast ephemeris and PPP-B2B correction;
S200, performing precise data recovery by using the observation data and the broadcast data to obtain a real-time precise orbit and a real-time precise satellite clock error of the Beidou satellite;
s300, establishing a PPP time service model considering time-varying deviation of a receiver according to the real-time precise orbit and the real-time precise satellite clock difference;
s400, outputting the receiver clock difference of the current epoch by using the PPP timing model;
S500, carrying out abnormality detection on the receiver clock difference of the current epoch, and if the receiver clock difference is abnormal, fitting the receiver clock difference of the current epoch by using the receiver clock difference of the history epoch; outputting the receiver clock difference of the current epoch if no abnormality exists;
And S600, performing real-time regulation and control on the crystal oscillator by using a clock control method, and inputting signals output by the crystal oscillator to a receiver, so that the receiver outputs UTC time and 1PPS signals according to the receiver clock difference of the current epoch.
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