High-precision time service, time keeping and positioning integrated system and method based on Beidou satellite system III
阅读说明：本技术 一种基于北斗三号卫星系统的高精度授时、守时、定位一体化系统及方法 (High-precision time service, time keeping and positioning integrated system and method based on Beidou satellite system III ) 是由 臧志斌 傅宁 马军 夏传福 吴小鸥 于 2019-11-26 设计创作，主要内容包括：本发明涉及一种基于北斗三号卫星系统的高精度授时、守时、定位一体化系统及方法,包括MCU处理单元以及与其相连的GNSS定位授时解算单元、GNSS守时单元、4G通信单元、多通道授时接口、显示单元；还包括与GNSS定位授时解算单元相连的GNSS有源天线、与4G通信单元相连的4G通讯天线；本发明实现了集授时、守时、定位一体化的目的。(The invention relates to a high-precision time service, time keeping and positioning integrated system and method based on a Beidou third satellite system, which comprises an MCU (microprogrammed control Unit) processing unit, and a GNSS positioning time service resolving unit, a GNSS time keeping unit, a 4G communication unit, a multi-channel time service interface and a display unit which are connected with the MCU processing unit; the GNSS active antenna is connected with the GNSS positioning time service resolving unit, and the 4G communication antenna is connected with the 4G communication unit; the invention realizes the integration of time service, time keeping and positioning.)
1. A high-precision time service, time keeping and positioning integrated system based on a Beidou satellite system III is characterized by comprising an MCU processing unit, a GNSS positioning time service resolving unit, a GNSS time keeping unit, a 4G communication unit, a multi-channel time service interface and a display unit, wherein the GNSS positioning time service resolving unit, the GNSS time keeping unit, the 4G communication unit, the multi-channel time service interface and the display unit are connected with the MCU processing unit; the GNSS active antenna is connected with the GNSS positioning time service resolving unit, and the 4G communication antenna is connected with the 4G communication unit;
the GNSS active antenna receives the BDS B1 signal and the GPS L1 signal, amplifies the signals and transmits the amplified signals to the GNSS positioning time service resolving unit; the GNSS positioning time service resolving unit is simultaneously connected with the 4G communication unit and the GNSS time keeping unit, tracks and captures a BDS B1 signal and a GPS L1 signal, and resolves positioning information and time information; the 4G communication antenna receives RTK differential data and transmits the RTK differential data to the 4G communication unit for data intercommunication among the platforms; the GNSS time keeping unit is used for maintaining time information after the satellite signals are out of lock; the multichannel time service interface is connected with the electric power post-stage equipment to realize active time service.
2. The high-precision time service, time keeping and positioning integrated system based on the Beidou third satellite system is characterized in that the GNSS positioning time service resolving unit tracks BDS B1 and GPS L1 signals, receives original observed quantity input, fixes a carrier period N value, and resolves centimeter-level position solution and 20 ns-level time solution.
3. The high-precision time service, time keeping and positioning integrated system based on the Beidou third satellite system is characterized in that the original observed quantity is differential data in an RTCM3.2 format and comes from a ChindCM service.
4. The high-precision time service, time keeping and positioning integrated system based on the Beidou third satellite system is characterized in that after positioning is successfully performed, the GNSS time keeping unit realizes high-precision domestication of a local clock by adopting a satellite second pulse signal 1 PPS.
5. The high-precision time service, time keeping and positioning integrated system based on the Beidou third satellite system is characterized in that the GNSS time keeping unit realizes high-precision domestication of a local clock by adopting a satellite second pulse signal 1PPS and specifically comprises the following steps: the GNSS time keeping unit extracts the CA code of the BDS B1 through radio frequency down-conversion, performs correlation value operation on the CA code and the CA code output by the local CA code generator to obtain a local clock error, sends the clock error to the voltage control end of the phase-locked loop after passing through an n-order low-pass filter, adjusts the output frequency of the phase-locked loop and feeds the frequency back to the local CA code generator to be used as a reference clock of the local CA code generator; and the satellite pulse-per-second signal 1PPS signal is controlled by a temperature compensated crystal oscillator TXCO after passing through a low-pass filter, so that the stability of the local carrier frequency is improved.
6. The high-precision time service, time keeping and positioning integrated system based on the Beidou third satellite system is characterized in that the multichannel time service interface comprises a radio frequency SMA interface used for outputting 1PPS pulses and a serial interface used for outputting timestamp messages, the 1PPS pulses directly adopt the 1PPS signals output by the GNSS positioning time service resolving unit when satellite signals exist, and the 1PPS pulses use the tamed 1PPS signals of the GNSS time keeping unit when no satellite signals exist; the rising edge of the 1PPS pulse indicates the time of the second, and the timestamp message indicates the year, month, day, hour, minute and second of the occurrence.
7. The high-precision time service, timekeeping and positioning integrated system based on the Beidou third satellite system is characterized in that two data channels socket1 and socket 2 are established in 4G communication between a 4G communication unit and a 4G communication antenna, wherein socket1 is connected to a thousand seeking FindCM server, and socket 2 is connected to a monitoring platform server.
8. The high-precision time service, time keeping and positioning integrated method based on the Beidou third satellite system of any one of claims 1 to 8 is characterized by comprising the following steps of:
acquiring differential data from a thousand-seek mode, and sending the differential data to a GNSS positioning time service unit to participate in resolving of positioning time service;
the calculated positioning time service information is displayed through a display unit on one hand, and is transmitted to a rear-stage terminal device needing time service through a multi-channel time service interface on the other hand;
when the GNSS positioning time service unit cannot track the satellite in real time due to external factors, the GNSS time keeping unit is used for taming the local clock to achieve the time keeping effect.
9. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the method steps of claim 8.
Technical Field
The invention relates to the technical field of satellite navigation, in particular to a high-precision time service, time keeping and positioning integrated system and method based on a Beidou satellite system III.
Background
With the rapid development of the Beidou navigation industry, more and more products are available in the market for positioning, time service and time keeping. However, these products cannot be integrated, and have the problem of insufficient positioning precision or punctuality accuracy, and cannot be put into market application. The time and space integration is more studied for the power industry, the requirement of high-precision positioning is provided for equipment, and the requirement of high-precision time service and time keeping can be realized.
Disclosure of Invention
In view of the above, the invention aims to provide a high-precision time service, time keeping and positioning integrated system and method based on the Beidou third satellite system, so as to achieve the purpose of integrating time service, time keeping and positioning.
The invention is realized by adopting the following scheme: a high-precision time service, time keeping and positioning integrated system based on a Beidou third satellite system comprises an MCU processing unit, and a GNSS positioning time service resolving unit, a GNSS time keeping unit, a 4G communication unit, a multi-channel time service interface and a display unit which are connected with the MCU processing unit; the GNSS active antenna is connected with the GNSS positioning time service resolving unit, and the 4G communication antenna is connected with the 4G communication unit;
the GNSS active antenna receives the BDS B1 signal and the GPS L1 signal, amplifies the signals and transmits the amplified signals to the GNSS positioning time service resolving unit; the GNSS positioning time service resolving unit is simultaneously connected with the 4G communication unit and the GNSS time keeping unit, tracks and captures a BDS B1 signal and a GPS L1 signal, and resolves positioning information and time information; the 4G communication antenna receives RTK differential data and transmits the RTK differential data to the 4G communication unit for data intercommunication among the platforms; the GNSS time keeping unit is used for maintaining time information after the satellite signals are out of lock; the multichannel time service interface is connected with the electric power post-stage equipment to realize active time service.
Further, the GNSS positioning time service resolving unit tracks BDS B1 and GPS L1 signals, receives original observation quantity input, fixes a carrier period N value, and resolves centimeter-level position solution and 20 ns-level time solution.
The original observation quantity is differential data in an RTCM3.2 format and comes from a thousand FindCM service, wherein socket1 receives the differential data from the thousand FindCM service, and a mounting point is RTCM32_ GGB. The differential data is in RTCM3.2 format, and the differential text ID is: 1005(10),1074(1),1084(1),1124(1).
Further, after successful positioning, the GNSS time keeping unit adopts a satellite second pulse signal 1PPS to implement high-precision taming of a local clock. The method specifically comprises the following steps: the GNSS time keeping unit extracts the CA code of the BDS B1 through radio frequency down-conversion, performs correlation value operation on the CA code and the CA code output by the local CA code generator to obtain a local clock error, sends the clock error to the voltage control end of the phase-locked loop after passing through an n-order low-pass filter, adjusts the output frequency of the phase-locked loop and feeds the frequency back to the local CA code generator to be used as a reference clock of the local CA code generator; and the satellite pulse-per-second signal 1PPS signal is controlled by a temperature compensated crystal oscillator TXCO after passing through a low-pass filter, so that the stability of the local carrier frequency is improved. The whole loop can be converged at last, namely, the phase-locked loop can output a stable and highly accurate clock, and the domestication and the maintenance of the local clock are realized.
Furthermore, the multi-channel time service interface (comprising eight time service channels) comprises a radio frequency SMA interface for outputting 1PPS pulse and a serial interface for outputting timestamp messages, wherein the 1PPS pulse directly adopts the 1PPS signal output by the GNSS positioning time service resolving unit when satellite signals exist, and the 1PPS pulse uses the domesticated 1PPS signal of the GNSS time service unit when the satellite signals do not exist; the rising edge of the 1PPS pulse indicates the time of the second, and the timestamp message indicates the year, month, day, hour, minute and second of the occurrence.
Further, two data channels socket1 and
Preferably, the display unit is used for displaying the positioning information, the time information and other information.
Preferably, the system further comprises a power management unit for power access management. Including AC-DC conversion, backup power, over-current over-voltage protection, anti-reverse protection, ESD protection, etc.
Preferably, the GNSS active antenna has multipath resistance and out-of-band large signal interference resistance, and good noise coefficient and gain parameters, realizes signal amplification of BDS B1 and GPS L1, and transmits the signals to the GNSS positioning time service resolving unit through a wire communication RF cable.
Preferably, the MCU processing unit obtains differential data from the thousand-hunt through socket1 of the 4G module, and sends the differential data to the GNSS positioning time service unit to participate in the solution of positioning time service. And on the one hand, the calculated positioning time service information is displayed through a display unit, and on the other hand, the positioning time service information is transmitted to a rear-stage terminal device needing time service, such as an electric power DTU/FTU and the like, through a multi-channel time service interface. The Beidou/GPS positioning time service unit can not track the satellite in real time due to external factors, so that the time keeping unit is added to discipline the local clock, and the time keeping effect is achieved. And finally, the MCU can be connected to a background server through a
The invention also provides a high-precision time service, time keeping and positioning integrated method based on the Beidou third satellite system, which comprises the following steps of:
acquiring differential data from a thousand-seek mode, and sending the differential data to a GNSS positioning time service unit to participate in resolving of positioning time service;
the calculated positioning time service information is displayed through a display unit on one hand, and is transmitted to a rear-stage terminal device needing time service through a multi-channel time service interface on the other hand;
when the GNSS positioning time service unit cannot track the satellite in real time due to external factors, the GNSS time keeping unit is used for taming the local clock to achieve the time keeping effect.
The invention also provides a computer-readable storage medium, in which a computer program is stored, which, when being executed by a processor, carries out the method steps as described above.
Compared with the prior art, the invention has the following beneficial effects: the invention realizes the functions of time service, time keeping and positioning integration, and can ensure the positioning precision and the time keeping accuracy.
Drawings
FIG. 1 is a schematic block diagram of an embodiment of the present invention.
Fig. 2 is a schematic block diagram of a GNSS time keeping unit according to an embodiment of the present invention.
FIG. 3 is a schematic diagram of an embodiment of a GNSS active antenna circuit.
FIG. 4 is a schematic circuit diagram of a GNSS positioning time service resolving unit according to an embodiment of the present invention.
FIG. 5 is a schematic circuit diagram of a GNSS time keeping unit according to an embodiment of the present invention.
Fig. 6 is a schematic circuit diagram of a 4G communication unit according to an embodiment of the present invention.
FIG. 7 is a diagram illustrating an exemplary positioning effect of the present invention. Wherein, (a) is a static positioning out-of-scene coincidence target map. (b) And fixing the local enlarged view after solution for the static positioning scene.
FIG. 8 is a diagram illustrating serial port output timing information according to an embodiment of the present invention.
FIG. 9 is a circuit diagram of a multi-channel time service interface according to an embodiment of the invention.
Detailed Description
The invention is further explained below with reference to the drawings and the embodiments.
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. 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.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
As shown in fig. 1, the embodiment provides a high-precision time service, time keeping and positioning integrated system based on a beidou three-satellite system, which includes an MCU processing unit, and a GNSS positioning time service resolving unit, a GNSS time keeping unit, a 4G communication unit, a multi-channel time service interface and a display unit connected thereto; the GNSS active antenna is connected with the GNSS positioning time service resolving unit, and the 4G communication antenna is connected with the 4G communication unit;
the GNSS active antenna receives the BDS B1 signal and the GPS L1 signal, amplifies the signals and transmits the amplified signals to the GNSS positioning time service resolving unit; the GNSS positioning time service resolving unit is simultaneously connected with the 4G communication unit and the GNSS time keeping unit, tracks and captures a BDS B1 signal and a GPS L1 signal, and resolves positioning information and time information; the 4G communication antenna receives RTK differential data and transmits the RTK differential data to the 4G communication unit for data intercommunication among the platforms; the GNSS time keeping unit is used for maintaining time information after the satellite signals are out of lock; the multichannel time service interface is connected with the electric power post-stage equipment to realize active time service.
In this embodiment, the GNSS positioning time service resolving unit tracks signals BDS B1 and GPS L1, receives an original observation input, fixes a carrier period N value, and resolves a centimeter-level position solution and a 20 ns-level time solution.
The original observation quantity is differential data in an RTCM3.2 format and comes from a thousand FindCM service, wherein socket1 receives the differential data from the thousand FindCM service, and a mounting point is RTCM32_ GGB. The differential data is in RTCM3.2 format, and the differential text ID is: 1005(10),1074(1),1084(1),1124(1).
A circuit diagram of the GNSS positioning time service resolving unit is shown in FIG. 4. The chip signal used was ATGS 01.
In this embodiment, after successful positioning, the GNSS time keeping unit adopts the satellite pulse-per-second signal 1PPS to implement high-precision taming of the local clock. The method specifically comprises the following steps: the GNSS time keeping unit extracts the CA code of the BDS B1 through radio frequency down-conversion, performs correlation value operation on the CA code and the CA code output by the local CA code generator to obtain a local clock error, sends the clock error to the voltage control end of the phase-locked loop after passing through an n-order low-pass filter, adjusts the output frequency of the phase-locked loop and feeds the frequency back to the local CA code generator to be used as a reference clock of the local CA code generator; and the satellite pulse-per-second signal 1PPS signal is controlled by a temperature compensated crystal oscillator TXCO after passing through a low-pass filter, so that the stability of the local carrier frequency is improved. The whole loop can be converged at last, namely, the phase-locked loop can output a stable and highly accurate clock, and the domestication and the maintenance of the local clock are realized.
The schematic diagram of the GNSS time keeping unit is shown in fig. 2, and the circuit diagram is shown in fig. 5.
In this embodiment, the multi-channel time service interface (including eight time service channels) includes a radio frequency SMA interface for outputting 1PPS pulses and a serial interface for outputting timestamp messages, the 1PPS pulses directly adopt 1PPS signals output by the GNSS positioning time service resolving unit when there are satellite signals, and the 1PPS pulses use the taminated 1PPS signals of the GNSS time keeping unit when there are no satellite signals; the rising edge of the 1PPS pulse indicates the time of the second, and the timestamp message indicates the year, month, day, hour, minute and second of the occurrence. The circuit of the multi-channel time service interface is shown in fig. 9.
In this embodiment, two data channels socket1 and
Preferably, the display unit is used for displaying the positioning information, the time information and other information.
Preferably, the system further comprises a power management unit for power access management. Including AC-DC conversion, backup power, over-current over-voltage protection, anti-reverse protection, ESD protection, etc.
Preferably, the GNSS active antenna has multipath resistance and out-of-band large signal interference resistance, and good noise coefficient and gain parameters, realizes signal amplification of BDS B1 and GPS L1, and transmits the signals to the GNSS positioning time service resolving unit through a wire communication RF cable. The circuit diagram of the GNSS active antenna is shown in fig. 3.
Preferably, the MCU processing unit obtains differential data from the thousand-hunt through socket1 of the 4G module, and sends the differential data to the GNSS positioning time service unit to participate in the solution of positioning time service. And on the one hand, the calculated positioning time service information is displayed through a display unit, and on the other hand, the positioning time service information is transmitted to a rear-stage terminal device needing time service, such as an electric power DTU/FTU and the like, through a multi-channel time service interface. The Beidou/GPS positioning time service unit can not track the satellite in real time due to external factors, so that the time keeping unit is added to discipline the local clock, and the time keeping effect is achieved. And finally, the MCU can be connected to a background server through a
The embodiment also provides a high-precision time service, time keeping and positioning integrated method based on the Beidou third satellite system, which comprises the following steps of:
acquiring differential data from a thousand-seek mode, and sending the differential data to a GNSS positioning time service unit to participate in resolving of positioning time service;
the calculated positioning time service information is displayed through a display unit on one hand, and is transmitted to a rear-stage terminal device needing time service through a multi-channel time service interface on the other hand;
when the GNSS positioning time service unit cannot track the satellite in real time due to external factors, the GNSS time keeping unit is used for taming the local clock to achieve the time keeping effect.
The present embodiment also provides a computer-readable storage medium, in which a computer program is stored, which, when being executed by a processor, carries out the method steps as described above.
Preferably, as shown in fig. 7, the positioning effect diagram of the present embodiment shows from the external coincidence target diagram, the device has a small amount of floating solution (RTK initialization) precision of about 2m, the floating solution precision is within 0.5m (99% CEP) immediately after the fixed solution is obtained, and as can be seen from the partially enlarged view, the positioning error is less than 10cm after the fixed solution is obtained.
Fig. 8 shows that time information can be output according to the NMEA-0183 protocol (which time is determined on which day and which month of the year, and which day of the year, and several minutes and seconds are determined), and the time corresponding to the time-keeping second pulse can be accurately known by combining the rising edge of the t second pulse in the time-keeping second pulse output by the serial port, so that the time accuracy can reach 20 ns., and in addition, through tests, the difference △ t =20.0095us/12h (about 0.834 us/h) between the measurement value of one tenth of the period of 1PPS after 24 hours of satellite lock loss and the measurement value before satellite lock loss is obtained, the index is superior to that of the time
The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.
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