CN114488203A - High-precision time keeping and network time service system and method based on Beidou signals - Google Patents
High-precision time keeping and network time service system and method based on Beidou signals Download PDFInfo
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- CN114488203A CN114488203A CN202210107136.7A CN202210107136A CN114488203A CN 114488203 A CN114488203 A CN 114488203A CN 202210107136 A CN202210107136 A CN 202210107136A CN 114488203 A CN114488203 A CN 114488203A
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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
- G01S19/14—Receivers specially adapted for specific applications
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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
- G01S19/35—Constructional details or hardware or software details of the signal processing chain
- G01S19/37—Hardware or software details of the signal processing chain
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- G—PHYSICS
- G04—HOROLOGY
- G04F—TIME-INTERVAL MEASURING
- G04F5/00—Apparatus for producing preselected time intervals for use as timing standards
- G04F5/14—Apparatus for producing preselected time intervals for use as timing standards using atomic clocks
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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
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Abstract
The invention relates to a high-precision time keeping and network time service system and method based on Beidou signals, wherein the system comprises the following components: the north three-antenna module is used for receiving and filtering electromagnetic wave signals of three frequency points in the north and outputting radio frequency signals; the north three-signal processing module receives the radio-frequency signals output by the north three-antenna module, processes the radio-frequency signals, completes input capture, PVT resolving, data analysis and storage of the north three-signal, and outputs Beidou time information, wherein the Beidou time information comprises TOD (time of day) and 1PPS (pulse per second) time information; the rubidium atomic clock time keeping module receives the TOD and 1PPS time information output by the north three-signal processing module, performs time keeping operation, and outputs accumulated standard TOD time information and a high-precision 1PPS edge; the network time service module is used for receiving the TOD time information and the high-precision 1PPS edge information output by the rubidium atomic clock time keeping module and carrying out network time service; and a power supply module. The system and the method can be used for high-precision time keeping and network time service.
Description
Technical Field
The invention relates to the field of Beidou third-generation satellite time service, in particular to a high-precision timekeeping and network time service system and method based on Beidou third-generation signals.
Background
With the completion of global arrangement of the Beidou third satellite, the Beidou third satellite system has the characteristic of high-precision time which becomes a big bright spot. However, how to fully utilize the characteristic of the Beidou third satellite in each industry becomes a problem that people think.
At present, a Beidou receiver in the market can only realize real-time positioning and timing of Beidou, but after Beidou signals are shielded, time can deviate, and network time equipment in the market often cannot meet expected requirements due to the fact that no high-precision time source exists.
How to utilize the high-precision time of the Beidou satellite three system to realize high-precision ground timekeeping and network time service becomes a problem to be solved urgently.
Disclosure of Invention
The invention aims to solve the technical problem that the Beidou third (also called as 'North third') satellite signal receiving, the timekeeping of a ground system and the existing common network time system are combined, Beidou time is introduced into the network system, and the Beidou time is continuously available with high precision for a long time, so that a high-precision time system integrating the timekeeping and the network propagation time is formed, and the requirements of various industries on the continuous high-precision time system are met.
In order to solve the above technical problem, according to an aspect of the present invention, there is provided a high-precision time keeping and network time service system based on a beidou signal, including: the north three-antenna module is used for receiving and filtering electromagnetic wave signals of north three frequency points and outputting radio frequency signals; the north three-antenna module is connected with the north three-antenna module, receives the radio-frequency signals output by the north three-antenna module, processes the radio-frequency signals, completes input capture, PVT (position, velocity and time) solution, data analysis and storage of the north three-antenna module, and outputs Beidou time information, wherein the Beidou time information comprises TOD (time of day) and 1PPS (pulse per second, 1PPS ═ 1Hz) time information; the rubidium atomic clock time keeping module is connected with the north three-signal processing module, receives the TOD and 1PPS time information output by the north three-signal processing module, performs time keeping operation, and outputs accumulated standard TOD time information and a high-precision 1PPS edge; the network time service module is connected with the rubidium atomic clock time keeping module, receives the TOD time information and the high-precision 1PPS edge information output by the rubidium atomic clock time keeping module, and carries out network time service; and the power supply module is used for providing electric energy for the high-precision time keeping and network time service system.
According to the embodiment of the invention, the north three antenna module can comprise a receiving antenna of a B1/B2/B3 frequency band and a low noise amplifier, wherein the low noise amplifier is used for amplifying and filtering satellite signals received by the antenna.
According to an embodiment of the present invention, the north three signal processing module may include: the up-down frequency conversion channel is used for respectively completing conversion from intermediate frequency to radio frequency, conversion from radio frequency to intermediate frequency, filtering and modulation of baseband spread spectrum data; an AD (analog-digital) sampling chip which finishes the digitization of analog intermediate frequency; and the baseband processing chip completes the positioning and timing functions of the third north, and realizes communication with external equipment through a serial port of the baseband processing chip.
According to an embodiment of the invention, the rubidium atomic clock timekeeping module may include a rubidium atomic clock, an FPGA (Field-Programmable Gate Array) chip, and an ARM chip, wherein the time deviation is estimated and corrected by using a Kalman (Kalman) filtering algorithm inside the ARM chip, a DAC (digital-to-analog converter) chip is used for digital-to-analog conversion, and the 1PPS output of the rubidium clock is voltage-controlled and adjusted.
According to the embodiment of the invention, the network time service module and the rubidium atomic clock timekeeping module can share an FPGA chip and an ARM chip, the FPGA chip is provided with a high-speed bus clock, a hardware Access controller (MAC) receiving end and an Ethernet functional unit, wherein the hardware MAC receiving end of the FPGA chip records a time starting edge, a parallel bus mode is adopted to transmit a time delay Delta _ T (time difference) between the FPGA chip and the ARM chip, the time delay Delta _ T is optimized by using a Kalman filtering algorithm in the ARM chip and is transmitted back to the FPGA chip by using a bus mode, the FPGA chip and the ARM chip are in work division cooperation, and the FPGA chip is responsible for capturing precise time and carrying out interaction of input and output of a filtering algorithm and an ARM message (message).
According to the embodiment of the invention, the high-precision timekeeping and network time service system can also comprise a display control unit, wherein the display control unit comprises a processor, a display screen, an indicator light and a key, and the display control unit is connected with the processor and is used for completing communication and control of all modules in the system, state display of all modules, network IP setting, current time display, expansion and management of external interfaces and man-machine interaction.
According to another aspect of the invention, a method for performing high-precision time keeping and network time service by using a high-precision time keeping and network time service system based on a Beidou signal is provided, the high-precision time keeping and network time service system based on the Beidou signal comprises a north three-antenna module, a north three-signal processing module, a rubidium atomic clock time keeping module, a network time service module and a power supply module, and the method comprises the following steps: s1, receiving signals, completing the receiving and filtering processing of electromagnetic wave signals of three frequency points in the north by the three-antenna module in the north, and outputting radio frequency signals; s2, processing the three north signals, wherein the three north signal processing module is connected with the three north antenna module, receives the radio frequency signals output by the three north antenna module, processes the radio frequency signals, completes input capture, PVT resolving, data analysis and storage of the three north signals, and outputs Beidou time information, wherein the Beidou time information comprises TOD (time of day) and 1PPS (pulse per second) time information; s3, keeping time of the rubidium atomic clock, wherein the time keeping module of the rubidium atomic clock is connected with the north three-signal processing module, receives TOD and 1PPS time information output by the north three-signal processing module, performs time keeping operation, and outputs accumulated standard TOD time information and a high-precision 1PPS edge; and S4, network time service, wherein the network time service module is connected with the rubidium atomic clock time keeping module, and the TOD time information and the high-precision 1PPS edge information output by the rubidium atomic clock time keeping module are received for network time service.
According to an embodiment of the present invention, the north three signal processing step may include the following sub-steps: s21, the three north information processing module receives the radio frequency signals from the three north antenna module to capture and track, so as to stably track more than four satellite signals; s22, the north three information processing module starts positioning and timing calculation, and after T1 time, the receiver clock error (user clock error) and the frequency difference converge to stable values; s23, the north three information processing module controls the sampling number between two times of resolving to make the difference value between the resolving time and the whole second time within 1 sampling interval period, and the difference value is executed 1 time after each resolving is started, and the process is called coarse tuning; s24, setting the difference value to DELTA _ T second within 1 sampling interval PERIOD between the rough-adjusted second pulse of the resolving time and UTC whole second time, controlling the next resolving PERIOD to be 1+ DELTA _ T second, synchronizing the next second pulse of the resolving time and the whole second time, then, carrying out fine adjustment, carrying out 1 time after each resolving is finished, modifying the resolving PERIOD to change the PERIOD of the sampling interval between two resolving, and changing the PERIOD of the sampling interval to MEAS _ PERIOD + DELTA _ T second; s25, positioning, timing calculation and sampling interval calculation of the three north information processing modules are completed in the information processing unit, then calculation results are packaged in the signal processing module according to a standard Beidou data interface protocol, and Beidou time information is output to the outside after packaging is completed.
According to an embodiment of the invention, the rubidium atomic clock timekeeping step can comprise the following sub-steps: s31, the rubidium atomic clock timekeeping module receives TOD +1PPS time information from the north three information processing units; s32, converting the current TOD time information into a count value which can be identified and accumulated by an internal register through a rubidium atomic clock timekeeping module, and locking a 1PPS edge of the Beidou; s33, comparing the locked Beidou 1PPS time information edge with the 1PPS edge output by the rubidium atomic clock timekeeping module, recording the error DELTA _ T of the two time edges, optimally estimating and correcting the time deviation DELTA _ T by adopting a Kalman filtering algorithm in the ARM chip, converting the estimation result into an analog signal by adopting a DAC digital-to-analog conversion chip, and outputting the analog signal to control the rubidium atomic clock; s34, compensating the Delta _ T time difference into the 1PPS output by the rubidium atomic clock, so that the 1PPS output by the rubidium atomic clock and the 1PPS output by the Beidou have equivalent precision, and the stability of the rubidium atomic clock is higher than that of the 1PPS information of the Beidou due to the principle of closed-loop control; s35, recording and adjusting parameters and correcting the precision and stability of 1PPS by continuous closed-loop adjustment inside the rubidium atomic clock timekeeping module, accumulating the 1PPS time of high precision by a FGPA chip in a second level, packing TOD data according to a Beidou standard data interface protocol, and outputting the accumulated standard TOD time information and the 1PPS edge of high precision to the outside.
According to the embodiment of the invention, the network time service step can comprise the following sub-steps: s41, the network time service module receives serial TOD time information and high-precision 1PPS second edge information of the rubidium atomic clock timekeeping module, and a time counting unit is accurate to nanosecond level by utilizing a high-speed bus clock in the FPGA chip; s42, configuring Network MAC and IP bottom layer information by the Ethernet function unit in the FPGA chip, packaging Time data by the NTP Network Time Protocol of the ARM chip Network application layer, responding the Time information request of the client in real Time, and completing the Network Time synchronization of the client by NTP (Network Time Protocol); s43, the network Time service module configures network MAC and IP bottom layer data by using an Ethernet functional unit in an FPGA chip, a hardware timestamp is marked on an MAC layer, a delay D1 brought by an operating system Protocol stack is eliminated, a Kalman filtering algorithm is used for filtering jitter, a network uplink and downlink jitter delay D2 is eliminated, and messages such as timestamps T1, T2, T3, T4, equipment diagnosis, Time source optimization and the like are transmitted between a server and a client by using PTP (precision Time Protocol) of IEEE1588 precision Time Protocol of a network application layer; s44, the network time service module recodes the received TOD and 1PPS time information, modulates the year, month, day, time, minute and second information of the TOD to an IO port of a single line according to different configurations of duty ratios, and realizes single line IRIG-B (DC) code output of the time information.
Compared with the prior art, the technical scheme provided by the embodiment of the application can at least realize the following beneficial effects:
1. according to the invention, the high-precision time of the Beidou is introduced into the network system, and the time keeping function is added, so that the advantages of all aspects are perfectly exerted, a unique high-precision time system is formed, and the requirements of various industries on the high-precision time are met.
2. In the invention, the sampling signal is subjected to coarse adjustment and fine adjustment, so that the sampling signal is accurately modulated, and the transmission precision and the sampling precision are ensured.
3. In the invention, the time of DELTA _ T is filtered by adopting a Kalman filtering algorithm, the precision of time keeping 1PPS is optimized, and the network time delays D1 and D2 are optimized, thereby ensuring the high precision of time.
4. In the invention, the design of each internal functional unit adopts the prior art, thereby reducing the design difficulty and shortening the research and development period.
5. In the invention, the network time service unit adopts an international standard network time service application protocol, thereby facilitating the interface with network equipment in various industries.
6. In the invention, the whole equipment adopts a standard 1U case structure, so that the frame-type installation is convenient, the front panel of the 1U case is provided with human-computer interaction functions such as a liquid crystal display screen, an LED lamp and keys, and the interface is friendly and humanized.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly described below, and it is apparent that the drawings in the following description only relate to some embodiments of the present invention and are not limiting on the present invention.
FIG. 1 is a block diagram of a high-precision time keeping and network time service system according to an embodiment of the present invention.
Fig. 2 is a schematic diagram illustrating an operation principle of a high-precision time keeping and network time service system according to an embodiment of the present invention.
Fig. 3 is a schematic diagram illustrating the working principle of a rubidium atomic clock timekeeping module according to an embodiment of the present invention.
FIG. 4 is a flow chart of network timing according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in the description and claims of the present application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. Also, the use of the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one.
FIG. 1 is a block diagram of a high-precision time keeping and network time service system according to an embodiment of the present invention. Fig. 2 is a schematic diagram illustrating an operation principle of a high-precision time keeping and network time service system according to an embodiment of the present invention.
As shown in fig. 1 and fig. 2, the high-precision timekeeping and network time service system based on the big dipper signal includes: the device comprises a north three antenna module, a north three signal processing module, a rubidium atomic clock timekeeping module, a network time service module and a power supply module.
The north three-antenna module is used for receiving and filtering electromagnetic wave signals of three frequency points in north and outputting radio frequency signals.
The north three-signal processing module is connected with the north three-antenna module, receives the radio frequency signal output by the north three-antenna module, processes the radio frequency signal, completes input capture, PVT (position, velocity and time), data analysis and storage of the north three-signal, and outputs Beidou time information, wherein the Beidou time information comprises TOD (time of day) and 1PPS (pulse per second, 1PPS ═ 1Hz) time information.
The rubidium atomic clock time keeping module is connected with the north three-signal processing module, receives TOD and 1PPS time information output by the north three-signal processing module, performs time keeping operation, and outputs accumulated standard TOD time information and a high-precision 1PPS edge.
And the network time service module is connected with the rubidium atomic clock timekeeping module, receives the TOD time information and the high-precision 1PPS edge information output by the rubidium atomic clock timekeeping module, and performs network time service.
The power module is used for providing electric energy for the high-precision time keeping and network time service system.
By introducing the high-precision time of the Beidou into a network system and adding a time keeping function, the advantages of all aspects are perfectly exerted, a unique high-precision time system is formed, and the requirement of various industries on the high-precision time is met.
According to one or some embodiments of the invention, the north three antenna module comprises a receiving antenna of a B1/B2/B3 frequency band and a low noise amplifier, wherein the low noise amplifier is used for amplifying and filtering satellite signals received by the antenna. The design of each internal functional unit adopts the prior art, reduces the design difficulty and shortens the research and development period.
According to one or some embodiments of the invention, the north three signal processing module comprises: the up-down frequency conversion channel is used for respectively completing conversion from intermediate frequency to radio frequency, conversion from radio frequency to intermediate frequency, filtering and modulation of baseband spread spectrum data; an AD (analog-digital) sampling chip which finishes the digitization of analog intermediate frequency; and the baseband processing chip completes the positioning and timing functions of the third north, and realizes communication with external equipment through a serial port of the baseband processing chip.
Fig. 3 is a schematic diagram illustrating the working principle of the rubidium atomic clock timekeeping module according to the embodiment of the invention.
As shown in fig. 3, the rubidium atomic clock timekeeping module includes a rubidium atomic clock, an FPGA (Field-Programmable Gate Array) chip, and an ARM chip, wherein the time deviation is estimated and corrected by using a Kalman (Kalman) filtering algorithm inside the ARM chip, a DAC (digital-to-analog converter) chip is used for digital-to-analog conversion, and the 1PPS output of the rubidium atomic clock is voltage-controlled and adjusted. By adopting a Kalman filtering algorithm to filter the DELTA _ T time, the accuracy of the time-keeping 1PPS is optimized, and the network time delays D1 and D2 are optimized, so that the high accuracy of the time is ensured.
FIG. 4 is a flow chart of network timing according to an embodiment of the present invention.
As shown in fig. 4, the network time service module and the rubidium atomic clock timekeeping module share an FPGA chip and an ARM chip, the FPGA chip has a high-speed bus clock, a Media Access controller (Media Access controller) receiving end and an ethernet functional unit, wherein the hardware MAC receiving end of the FPGA chip records a time start edge, a parallel bus mode is adopted to transmit a time delay DELTA _ T (time difference) between the FPGA chip and the ARM chip, the time delay DELTA _ T is optimized by using a kalman filter algorithm inside the ARM chip and is returned to the FPGA chip by using a bus mode, wherein the FPGA chip and the ARM chip work separately and cooperate, the FPGA chip is responsible for capturing precision time, and the ARM is responsible for performing interaction of input and output of a filter algorithm and a message (message).
According to one or some embodiments of the invention, the high-precision timekeeping and network time service system further comprises a display control unit, the display control unit comprises a processor, and a display screen, an indicator light and a key which are connected with the processor, and the display control unit is used for completing communication and control of each module in the system, state display of each module, network IP setting, current time display, expansion and management of an external interface and man-machine interaction. The whole standard 1U machine case structure that adopts of equipment makes things convenient for the rack-type installation, and 1U machine case front panel disposes human-computer interaction functions such as liquid crystal display, LED lamp, button, and the interface is friendly, humanized.
According to one or some embodiments of the invention, the method for performing high-precision time keeping and network time service by adopting the high-precision time keeping and network time service system based on the Beidou signal comprises the following steps: s1, receiving signals, completing the receiving and filtering processing of electromagnetic wave signals of three frequency points in the north by the three-antenna module in the north, and outputting radio frequency signals; s2, processing the three north signals, wherein the three north signal processing module is connected with the three north antenna module, receives the radio frequency signals output by the three north antenna module, processes the radio frequency signals, completes input capture, PVT resolving, data analysis and storage of the three north signals, and outputs Beidou time information, wherein the Beidou time information comprises TOD (time of day) and 1PPS (pulse per second) time information; s3, keeping time of the rubidium atomic clock, wherein the time keeping module of the rubidium atomic clock is connected with the north three-signal processing module, receives TOD and 1PPS time information output by the north three-signal processing module, performs time keeping operation, and outputs accumulated standard TOD time information and a high-precision 1PPS edge; and S4, network time service, wherein the network time service module is connected with the rubidium atomic clock time keeping module, and the TOD time information and the high-precision 1PPS edge information output by the rubidium atomic clock time keeping module are received for network time service.
According to one or some embodiments of the invention, the north three signal processing step comprises the sub-steps of: s21, the three north information processing module receives the radio frequency signals from the three north antenna module to capture and track, so as to stably track more than four satellite signals; s22, the north three information processing module starts positioning and timing calculation, and after T1 time, the receiver clock error (user clock error) and the frequency difference converge to stable values;
s23, the north three information processing module controls the sampling number between two times of resolving to make the difference value between the resolving time and the whole second time within 1 sampling interval period, and the difference value is executed 1 time after each resolving is started, and the process is called coarse tuning; s24, setting the difference value to DELTA _ T second within 1 sampling interval PERIOD between the rough-adjusted second pulse of the resolving time and UTC whole second time, controlling the next resolving PERIOD to be 1+ DELTA _ T second, synchronizing the next second pulse of the resolving time and the whole second time, then, carrying out fine adjustment, carrying out 1 time after each resolving is finished, modifying the resolving PERIOD to change the PERIOD of the sampling interval between two resolving, and changing the PERIOD of the sampling interval to MEAS _ PERIOD + DELTA _ T second; s25, positioning, timing calculation and sampling interval calculation of the three north information processing modules are completed in the information processing unit, then calculation results are packaged in the signal processing module according to a standard Beidou data interface protocol, and Beidou time information is output to the outside after packaging is completed. The sampling signal is subjected to coarse adjustment and fine adjustment, so that the sampling signal is accurately modulated, and the transmission precision and the sampling precision are ensured.
According to one or some embodiments of the invention, the rubidium atomic clock timekeeping step comprises the following sub-steps: s31, the rubidium atomic clock timekeeping module receives TOD +1PPS time information from the north three information processing units; s32, converting the current TOD time information into a count value which can be identified and accumulated by an internal register through a rubidium atomic clock timekeeping module, and locking a 1PPS edge of the Beidou; s33, comparing the locked Beidou 1PPS time information edge with the 1PPS edge output by the rubidium atomic clock timekeeping module, recording the error DELTA _ T of the two time edges, optimally estimating and correcting the time deviation DELTA _ T by adopting a Kalman filtering algorithm in the ARM chip, converting the estimation result into an analog signal by adopting a DAC digital-to-analog conversion chip, and outputting the analog signal to control the rubidium atomic clock; s34, compensating the Delta _ T time difference into the 1PPS output by the rubidium atomic clock, so that the 1PPS output by the rubidium atomic clock and the 1PPS output by the Beidou have equivalent precision, and the stability of the rubidium atomic clock is higher than that of the 1PPS information of the Beidou due to the principle of closed-loop control; s35, recording and adjusting parameters and correcting the precision and stability of 1PPS by continuous closed-loop adjustment inside the rubidium atomic clock timekeeping module, accumulating the 1PPS time of high precision by a FGPA chip in a second level, packing TOD data according to a Beidou standard data interface protocol, and outputting the accumulated standard TOD time information and the 1PPS edge of high precision to the outside.
According to one or some embodiments of the invention, the network time service step comprises the following sub-steps: s41, the network time service module receives serial TOD time information and high-precision 1PPS second edge information of the rubidium atomic clock timekeeping module, and a time counting unit is accurate to nanosecond level by utilizing a high-speed bus clock in the FPGA chip; s42, configuring Network MAC and IP bottom layer information by the Ethernet function unit in the FPGA chip, packaging Time data by the NTP Network Time Protocol of the ARM chip Network application layer, responding the Time information request of the client in real Time, and completing the Network Time synchronization of the NTP (Network Time Protocol) of the client; s43, the network Time service module configures network MAC and IP bottom layer data by using an Ethernet functional unit in an FPGA chip, a hardware timestamp is marked on an MAC layer, a delay D1 brought by an operating system Protocol stack is eliminated, a Kalman filtering algorithm is used for filtering jitter, a network uplink and downlink jitter delay D2 is eliminated, and messages such as timestamps T1, T2, T3, T4, equipment diagnosis, Time source optimization and the like are transmitted between a server and a client by using PTP (precision Time Protocol) of IEEE1588 precision Time Protocol of a network application layer; s44, the network time service module recodes the received TOD and 1PPS time information, modulates the year, month, day, time, minute and second information of the TOD to an IO port of a single line according to different configurations of duty ratios, and realizes single line IRIG-B (DC) code output of the time information. The network time service unit adopts an international standard network time service application protocol, and is convenient for interfacing with network equipment in various industries.
The above are exemplary embodiments of the invention only, and are not intended to limit the scope of the invention, which is defined by the appended claims.
Claims (10)
1. The utility model provides a high accuracy is punctual and network time service system based on big dipper signal, includes:
the north three-antenna module is used for receiving and filtering electromagnetic wave signals of three frequency points in the north and outputting radio frequency signals;
the north three-antenna module is connected with the north three-antenna module, receives the radio-frequency signal output by the north three-antenna module, processes the radio-frequency signal, completes input capture, PVT resolving, data analysis and storage of the north three-antenna module, and outputs Beidou time information, wherein the Beidou time information comprises TOD (time of day) and 1PPS (pulse per second) time information;
the rubidium atomic clock time keeping module is connected with the three-north-signal processing module, receives the TOD and 1PPS time information output by the three-north-signal processing module, performs time keeping operation, and outputs accumulated standard TOD time information and a high-precision 1PPS edge;
the network time service module is connected with the rubidium atomic clock time keeping module, receives the TOD time information and the high-precision 1PPS edge information output by the rubidium atomic clock time keeping module, and carries out network time service;
and the power supply module is used for providing electric energy for the high-precision time keeping and network time service system.
2. The system of claim 1, wherein the north three-antenna module comprises a receiving antenna of B1/B2/B3 frequency band and a low noise amplifier, and the low noise amplifier is used for amplifying and filtering satellite signals received by the antenna.
3. The high-precision timekeeping and network time service system of claim 1, wherein the north three-signal processing module comprises:
the up-down frequency conversion channel is used for respectively finishing conversion from intermediate frequency to radio frequency, conversion from radio frequency to intermediate frequency, filtering and modulation of baseband spread spectrum data;
the AD sampling chip is used for completing the digitization of the analog intermediate frequency;
and the baseband processing chip completes the positioning and timing functions of the third north and the fourth north and realizes communication with external equipment through a serial port of the baseband processing chip.
4. The high-precision timekeeping and network time service system of claim 1, wherein the rubidium atomic clock timekeeping module comprises a rubidium atomic clock, an FPGA chip and an ARM chip,
and estimating and correcting the time deviation by using a Kalman filtering algorithm in the ARM chip, performing digital-to-analog conversion by using a DAC chip, and performing voltage-controlled regulation on 1PPS output of the rubidium clock.
5. The high-precision timekeeping and network time service system of claim 4, wherein the network time service module and the rubidium atomic clock timekeeping module share the FPGA chip and the ARM chip, the FPGA chip has a high-speed bus clock, a hardware MAC receiving end and an Ethernet functional unit,
wherein, a time starting edge is recorded at a hardware MAC receiving end of the FPGA chip, a parallel bus mode is adopted to transmit a time delay Delta _ T between the FPGA chip and the ARM chip, the time delay Delta _ T is optimized by utilizing a Kalman filtering algorithm in the ARM chip and is transmitted back to the FPGA chip in a bus mode,
the FPGA chip is responsible for capturing precise time, and the ARM is responsible for carrying out interaction of a filtering algorithm and message input and output.
6. The system of claim 1, further comprising a display and control unit, wherein the display and control unit comprises a processor, a display screen, an indicator light and a key, the display and control unit is connected to the processor, and the display and control unit is configured to complete communication and control of each module in the system, status display of each module, network IP setting, current time display, expansion and management of an external interface, and human-computer interaction.
7. A method for performing high-precision time keeping and network time service by adopting a high-precision time keeping and network time service system based on Beidou signals comprises a north three-antenna module, a north three-signal processing module, a rubidium atomic clock time keeping module, a network time service module and a power supply module, and comprises the following steps:
s1, receiving signals, wherein the three-antenna-block-north module receives and filters electromagnetic wave signals of three frequency points in north and outputs radio frequency signals;
s2, processing the northern three-antenna signal, receiving the radio frequency signal output by the northern three-antenna module, processing, completing input capture, PVT resolving, data analysis and storage of the northern three-antenna signal, and outputting Beidou time information, wherein the Beidou time information comprises TOD (time of day) and 1PPS (pulse per second) time information;
s3, the rubidium atomic clock is timed, TOD and 1PPS time information output by the north three-signal processing module are received, the time-keeping operation is carried out, and accumulated standard TOD time information and a high-precision 1PPS edge are output;
and S4, network time service, namely receiving the TOD time information and the high-precision 1PPS edge information output by the rubidium atomic clock timekeeping module, and performing network time service.
8. The method of claim 7, wherein the north three signal processing step comprises the following sub-steps:
s21, the north three-information processing module receives the radio frequency signals from the north three-antenna module, and the radio frequency signals are captured and tracked to stably track more than four satellite signals;
s22, the north three information processing module starts positioning and timing calculation, and after T1 time, the receiver clock difference and frequency difference converge to stable values;
s23, the three-north information processing module controls the sampling number between two times of resolving to make the difference between the resolving time and the whole second time within 1 sampling interval period, and the difference is executed 1 time after each resolving is started, and the process is called coarse tuning;
s24, setting the difference value to DELTA _ T second within 1 sampling interval PERIOD between the rough-adjusted second pulse of the resolving time and UTC whole second time, controlling the next resolving PERIOD to be 1+ DELTA _ T second, synchronizing the next second pulse of the resolving time and the whole second time, then, performing fine adjustment, executing 1 time after each resolving is completed, wherein the fine adjustment is to modify the resolving PERIOD, the modified resolving PERIOD is to change the sampling interval between two resolving, and the PERIOD of the sampling interval is changed to MEAS _ PERIOD + DELTA _ T second;
s25, positioning, timing calculation and sampling interval calculation of the three north information processing modules are completed in the information processing unit, then calculation results are packaged in the signal processing module according to a standard Beidou data interface protocol, and Beidou time information is output to the outside after packaging is completed.
9. The high-precision timekeeping and network time service method of claim 7, wherein the rubidium atomic clock timekeeping step comprises the following substeps:
s31, the rubidium atomic clock timekeeping module receives TOD +1PPS time information from the north three information processing units;
s32, the rubidium atomic clock timekeeping module converts current TOD time information into a count value which can be identified and accumulated by an internal register, and locks a 1PPS edge of the Beidou;
s33, the rubidium atomic clock timekeeping module compares the locked Beidou 1PPS time information edges with the 1PPS edges output by the rubidium atomic clock, records the error DELTA _ T of the two time edges, optimally estimates and corrects the time deviation DELTA _ T by adopting a Kalman filtering algorithm in the ARM chip, converts the estimation result into an analog signal by adopting a DAC digital-to-analog conversion chip, and outputs the analog signal to control the rubidium atomic clock;
s34, compensating a DELTA _ T time difference into the 1PPS output by the rubidium atomic clock, wherein the 1PPS output by the rubidium atomic clock and the 1PPS output by the Beidou have equivalent precision, and the stability of the rubidium atomic clock is higher than that of the Beidou 1PPS information due to the principle of closed-loop control;
s35, recording and adjusting parameters and correcting the precision and stability of 1PPS through continuous closed-loop adjustment in the rubidium atomic clock timekeeping module, accumulating the 1PPS time with high precision by the FGPA chip in a second-level manner, packing TOD data according to a Beidou standard data interface protocol, and outputting accumulated standard TOD time information and a 1PPS edge with high precision to the outside.
10. The high-precision timekeeping and network time service method of claim 7, wherein the network time service step comprises the following substeps:
s41, the network time service module receives serial TOD time information and high-precision 1PPS second edge information of the rubidium atomic clock timekeeping module, and a time counting unit is accurate to a nanosecond level by utilizing a high-speed bus clock in the FPGA chip;
s42, the network time service module configures network MAC and IP bottom layer information by using the Ethernet function unit in the FPGA chip, packs time data by using the NTP network time protocol of the ARM chip network application layer, responds the time information request of the client in real time, and completes the NTP network time service of the client;
s43, configuring network MAC and IP bottom layer data by the network time service module through an Ethernet functional unit inside the FPGA chip, stamping a hardware timestamp on an MAC layer, eliminating delay D1 brought by an operating system protocol stack, filtering jitter by using a Kalman filtering algorithm, eliminating network uplink and downlink jitter delay D2, and transmitting messages such as timestamps T1, T2, T3 and T4, equipment diagnosis, time source optimization and the like between a server and a client through an IEEE1588 precision time protocol of a network application layer;
and S44, the network time service module recodes the received TOD and 1PPS time information, modulates the year, month, day, time, minute and second information of the TOD to an IO port of a single line according to different configurations of duty ratios, and realizes single-line IRIG-B code output of the time information.
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CN114706105A (en) * | 2022-06-07 | 2022-07-05 | 尚禹河北电子科技股份有限公司 | Method, device and system for capturing long-wave guide Beidou authorized signal |
CN115250215A (en) * | 2022-06-23 | 2022-10-28 | 北京燕山电子设备厂 | Multi-interface time baseband chip |
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CN114706105A (en) * | 2022-06-07 | 2022-07-05 | 尚禹河北电子科技股份有限公司 | Method, device and system for capturing long-wave guide Beidou authorized signal |
CN114706105B (en) * | 2022-06-07 | 2022-08-23 | 尚禹河北电子科技股份有限公司 | Method, device and system for capturing long-wave guide Beidou authorized signal |
CN115250215A (en) * | 2022-06-23 | 2022-10-28 | 北京燕山电子设备厂 | Multi-interface time baseband chip |
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