CN110971333B - Two-way time synchronization system and method based on free space laser communication - Google Patents
Two-way time synchronization system and method based on free space laser communication Download PDFInfo
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Abstract
The invention discloses a two-way time synchronization system and a method based on free space laser communication, which comprises the following steps: a first time synchronization terminal arranged at a first site; a second time synchronization terminal arranged at the second site; the time synchronization controller is connected with the first time synchronization terminal and the second time synchronization terminal; and the laser communication equipment is connected with the first station and the second station and is used for transmitting the time signal in the time synchronization process. The invention sets a time service unit for obtaining absolute time at a station, encodes and modulates a time signal, transmits the time signal to the atmosphere, and simultaneously the station can receive the time signal in the atmosphere through a set photoelectric detector, demodulate, decode and synchronize the time signal.
Description
Technical Field
The invention relates to the technical field of time service synchronization, in particular to a bidirectional time synchronization system and method based on free space laser communication.
Background
With the development of science and technology, the requirements of various industries on time synchronization are higher and higher, and the high-precision time synchronization provides safe and reliable guarantee for the fields of aerospace, radar synchronization, tip weapon control, high-speed communication, deep space exploration and the like. At present, the optical fiber time synchronization method can achieve synchronization precision of one hundred picoseconds, the equipment price is far lower than that of a satellite bidirectional comparison method, and meanwhile, due to the essential characteristic of an optical fiber shielding effect, the time service network based on the optical network has excellent anti-interference performance, so that the method is widely applied to time service schemes in various fields.
The laser communication mode based on the free space has the advantages of large communication capacity, no electromagnetic interference, strong confidentiality, light equipment, good maneuverability and capability of realizing point-to-point or point-to-multipoint, so that the laser communication mode based on the free space is added in the time service synchronization, and the laser communication mode based on the free space is a popular research direction in the technical field of time service synchronization.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a two-way time synchronization system and method based on free space laser communication.
A two-way time synchronization system based on free-space laser communication, comprising: the first time synchronization terminal is arranged at the first site, comprises a first timing unit and a time service unit, acquires standard time through the time service unit, and records first time difference information between second site time transmitted by the second site and current first site standard time by using the first timing unit; the second time synchronization terminal is arranged at the second site, comprises a second timing unit and a time synchronization unit, records second time difference information between a first site time signal transmitted by the first site and the current second site time through the second timing unit, and utilizes the time synchronization unit to receive a time synchronization signal sent by the time synchronization controller for time synchronization; the time synchronization controller is connected with the first time synchronization terminal and the second time synchronization terminal and is used for controlling the two sites to simultaneously transmit time signals to each other and generating time synchronization signals according to the time difference information recorded by the first timing unit and the second timing unit; and the laser communication equipment is connected with the first station and the second station and is used for transmitting the time signal in the time synchronization process.
Further, the two-way time synchronization system based on free space laser communication is characterized in that the time synchronization signal is used for adjusting the time of the second station, and the adjusted value is the average value of the vector difference between the first time difference information and the second time difference information.
Further, the two-way time synchronization system based on free space laser communication comprises a time service unit and a high-stability constant temperature crystal oscillator, wherein the time service unit comprises a GPS receiver and the high-stability constant temperature crystal oscillator connected with the GPS receiver, and the high-stability constant temperature crystal oscillator is acclimated by the GPS receiver to obtain a high-precision 1PPS time signal.
Furthermore, the two-way time synchronization system based on free space laser communication comprises a time encoder and a time decoder, wherein the time encoder and the time decoder are used for encoding and decoding transmitted time signals and are used for transmitting the time encoded signals.
Furthermore, the time coding signal adopts IRIG-B coding to store the time signal.
Further, the two-way time synchronization system based on free space laser communication comprises a laser for transmitting a time signal and a photoelectric detector for receiving the time signal.
Furthermore, the bidirectional time synchronization system based on free space laser communication also comprises signal modulation and demodulation units respectively arranged between the time signal transceiver and the first time synchronization terminal and between the time signal transceiver and the second time synchronization terminal, so as to realize the transmission and the reception of time coding signals.
Further, the two-way time synchronization system based on free space laser communication further comprises a collimating mirror arranged between the laser and the photoelectric detector, collimation of laser communication light beams is guaranteed, and the laser and the photoelectric detector realize shunting input and output of time coding signals between the first station and the second station through a connecting ring-shaped device.
A bidirectional time synchronization system based on free space laser communication further comprises a time synchronization unit arranged on a first time synchronization terminal and used for receiving a time synchronization signal and a time service unit arranged on a second time synchronization terminal and used for obtaining standard time.
A bidirectional time synchronization method based on free space laser communication comprises the following sub-steps:
s101: the first time synchronization terminal sends a first site time signal to the second site through the laser communication equipment according to the standard time received by the time service unit, and meanwhile, the second time synchronization terminal sends a second site time signal to the first site through the laser communication equipment according to the time information of the second site;
s201: the time synchronization controller calculates and obtains a time synchronization signal sent to the second time synchronization terminal according to first time difference information, recorded by the first time synchronization terminal, of second site time transmitted by the second site and current first site standard time and second time difference information, received by the second time synchronization terminal, of first site time transmitted by the first site and current second site standard time;
s301: and the second station utilizes the time synchronization unit to carry out event synchronization according to the received time synchronization signal of the second time synchronization terminal.
Further, the two-way time synchronization method based on free space laser communication is characterized in that the time synchronization signal is used for adjusting the time of the second station, and the adjusted value is the average value of the vector difference between the first time difference information and the second time difference information.
A bidirectional time synchronization method based on free space laser communication further comprises the following steps:
step S102: the second time synchronization terminal also sends a second site time signal to the first site through the laser communication equipment according to the standard time received by the time service unit, and meanwhile, the first time synchronization terminal sends a first site time signal to the second site through the laser communication equipment according to the time information of the first site;
step S202: the time synchronization controller calculates and obtains a time synchronization signal sent to the first time synchronization terminal according to second time difference information, recorded by the second time synchronization terminal, of first site time transmitted by the first site and current second site standard time and first time difference information, recorded by the first time synchronization terminal, of second site time transmitted by the second site and current first site standard time;
step S203: the first station performs event synchronization by using the time synchronization unit according to the received time synchronization signal of the first time synchronization terminal.
The invention has the beneficial effects that: the invention sets a time service unit for obtaining absolute time at a station, encodes and modulates a time signal, transmits the time signal to the atmosphere through a laser, and simultaneously the station can receive the time signal in the atmosphere through a set photoelectric detector, demodulate, decode and synchronize the time signal.
Drawings
Fig. 1 is a flow chart of a bidirectional time synchronization method based on free space laser communication according to the invention.
Fig. 2 is a schematic diagram of a one-way time synchronization system based on free space laser communication according to the present invention.
Fig. 3 is a schematic diagram of a bidirectional time synchronization system based on free space laser communication according to the present invention.
Detailed Description
In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings.
As shown in fig. 1, a bidirectional time synchronization method based on free space laser communication includes the following sub-steps:
s101: the first time synchronization terminal sends a first site time signal to the second site through the laser communication equipment according to the standard time received by the time service unit, and meanwhile, the second time synchronization terminal sends a second site time signal to the first site through the laser communication equipment according to the time information of the second site;
s201: the time synchronization controller calculates and obtains a time synchronization signal sent to the second time synchronization terminal according to first time difference information, recorded by the first time synchronization terminal, of second site time transmitted by the second site and current first site standard time and second time difference information, received by the second time synchronization terminal, of first site time transmitted by the first site and current second site standard time;
s301: and the second station utilizes the time synchronization unit to carry out event synchronization according to the received time synchronization signal of the second time synchronization terminal.
Further, the two-way time synchronization method based on free space laser communication is characterized in that the time synchronization signal is used for adjusting the time of the second station, and the adjusted value is the average value of the vector difference between the first time difference information and the second time difference information.
A bidirectional time synchronization method based on free space laser communication further comprises the following steps:
step S102: the second time synchronization terminal also sends a second site time signal to the first site through the laser communication equipment according to the standard time received by the time service unit, and meanwhile, the first time synchronization terminal sends a first site time signal to the second site through the laser communication equipment according to the time information of the first site;
step S202: the time synchronization controller calculates and obtains a time synchronization signal sent to the first time synchronization terminal according to second time difference information, recorded by the second time synchronization terminal, of first site time transmitted by the first site and current second site standard time and first time difference information, recorded by the first time synchronization terminal, of second site time transmitted by the second site and current first site standard time;
step S203: the first station performs event synchronization by using the time synchronization unit according to the received time synchronization signal of the first time synchronization terminal.
As shown in fig. 2, example 1: time is synchronized unidirectionally.
A two-way time synchronization system based on free-space laser communication, comprising: the first time synchronization terminal is arranged at the first site, comprises a first timing unit and a time service unit, acquires standard time through the time service unit, and records first time difference information between second site time transmitted by the second site and current first site standard time by using the first timing unit; the second time synchronization terminal is arranged at the second site, comprises a second timing unit and a time synchronization unit, records second time difference information between a first site time signal transmitted by the first site and the current second site time through the second timing unit, and utilizes the time synchronization unit to receive a time synchronization signal sent by the time synchronization controller for time synchronization; the time synchronization controller is connected with the first time synchronization terminal and the second time synchronization terminal and is used for controlling the two sites to simultaneously transmit time signals to each other and generating time synchronization signals according to the time difference information recorded by the first timing unit and the second timing unit; and the laser communication equipment is connected with the first station and the second station and is used for transmitting the time signal in the time synchronization process.
Preferably, the time synchronization signal is used to adjust the time of the second station, and the adjusted value is an average value of the vector difference between the first time difference information and the second time difference information.
Preferably, the time service unit comprises a GPS receiver and a high-stable-state constant-temperature crystal oscillator connected with the GPS receiver, the high-stable-state constant-temperature crystal oscillator is acclimated by the GPS receiver to obtain a high-precision 1PPS time signal, the time coding signal adopts IRIG-B coding to store the time signal, the time service unit comprises an FPGA controller and the GPS receiver which are arranged on an FPGA control board, the received time signal is compiled through the FPGA, and an IRIG-B code signal which is precisely synchronous with the GPS output signal 1PPS is generated.
Preferably, the high-stability constant temperature crystal oscillator adopts a 10MHz ultrahigh-stability OCXO module.
Preferably, the time signal transceiver includes a laser for transmitting the time signal and a photodetector for receiving the time signal, the laser and the photodetector realize the split input and output of the time coding signal between the first site and the second site by connecting the ring-shaped device, and the laser adopts a laser transmitter with 1550nm wavelength.
Preferably, the time signal transmitting and receiving device further comprises a signal modulation and demodulation unit respectively arranged between the time signal transmitting and receiving device and the first time synchronization terminal, and between the time signal transmitting and receiving device and the second time synchronization terminal, so as to realize the transmission and reception of the time coding signal.
Preferably, the laser device further comprises a collimating mirror arranged between the laser device and the photoelectric detector, and the collimation of the laser communication beam is ensured.
Specifically, in this embodiment, when performing time synchronization, the standard time of the first station after performing time calibration is 12 hours, 0 minutes and 0 seconds, and the time of the second station is 12 hours, 0 minutes and 10 seconds, the first time synchronization terminal of the first station and the second time synchronization terminal of the second station simultaneously transmit the time information of the first station to the other station, the transmission takes 7 seconds, the first station receives the time information of the second station, 12 hours, 0 minutes and 10 seconds, and the first time difference is-3 seconds; the second station receives the 12 hours 0 minutes 0 seconds time information of the first station in 12 hours 0 minutes 17 seconds, the second time difference is 17 seconds, and the average value of the vector difference between the first time difference and the second time difference is (-3-17)/2 = -10 seconds, so that the time synchronization signal received by the second station delays the time of the second station by 10 seconds, and the time service synchronization from the first station to the second station can be realized.
As shown in fig. 3, example 2: time is synchronized bidirectionally.
A two-way time synchronization system based on free-space laser communication, comprising: the first time synchronization terminal is arranged at the first site, comprises a first timing unit and a time service unit, acquires standard time through the time service unit, and records first time difference information between second site time transmitted by the second site and current first site standard time by using the first timing unit; the second time synchronization terminal is arranged at the second site, comprises a second timing unit and a time synchronization unit, records second time difference information between a first site time signal transmitted by the first site and the current second site time through the second timing unit, and utilizes the time synchronization unit to receive a time synchronization signal sent by the time synchronization controller for time synchronization; the time synchronization controller is connected with the first time synchronization terminal and the second time synchronization terminal and is used for controlling the two sites to simultaneously transmit time signals to each other and generating time synchronization signals according to the time difference information recorded by the first timing unit and the second timing unit; the laser communication equipment is connected with the first station and the second station and is used for transmitting time signals in the time synchronization process; the time synchronization unit is arranged on the first time synchronization terminal and used for receiving the time synchronization signal, and the time service unit is arranged on the second time synchronization terminal and used for obtaining the standard time.
Preferably, the time synchronization signal is a first adjustment of the time of the second station, and the value of the first adjustment is an average value of vector differences between the first time difference information and the second time difference information; or the time synchronization signal is used for carrying out second adjustment on the time of the first station, and the value of the second adjustment is the average value of the vector difference between the second time difference information and the first time difference information.
The invention sets a time service unit for obtaining absolute time at a station, encodes and modulates a time signal, transmits the time signal to the atmosphere through a laser, and simultaneously the station can receive the time signal in the atmosphere through a set photoelectric detector, demodulate, decode and synchronize the time signal.
The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (9)
1. A two-way time synchronization system based on free-space laser communication, comprising:
the first time synchronization terminal is arranged at the first site, comprises a first timing unit and a time service unit, acquires standard time through the time service unit, and records first time difference information between second site time transmitted by the second site and current first site standard time by using the first timing unit;
the second time synchronization terminal is arranged at the second site, comprises a second timing unit and a time synchronization unit, records second time difference information between a first site time signal transmitted by the first site and the current second site time through the second timing unit, and utilizes the time synchronization unit to receive a time synchronization signal sent by the time synchronization controller for time synchronization;
the time synchronization controller is connected with the first time synchronization terminal and the second time synchronization terminal and is used for controlling the two sites to simultaneously transmit time signals to each other and generating time synchronization signals according to the time difference information recorded by the first timing unit and the second timing unit;
the laser communication equipment is connected with the first station and the second station and is used for transmitting time signals in the time synchronization process;
the two-way time synchronization principle of the two-way time synchronization system based on free space laser communication is as follows:
s101: the first time synchronization terminal sends a first site time signal to the second site through the laser communication equipment according to the standard time received by the time service unit, and meanwhile, the second time synchronization terminal sends a second site time signal to the first site through the laser communication equipment according to the time information of the second site;
s201: the time synchronization controller calculates and obtains a time synchronization signal sent to the second time synchronization terminal according to first time difference information, recorded by the first time synchronization terminal, of second site time transmitted by the second site and current first site standard time and second time difference information, received by the second time synchronization terminal, of first site time transmitted by the first site and current second site standard time;
s301: the second station utilizes the time synchronization unit to carry out time synchronization according to the received time synchronization signal of the second time synchronization terminal; the time synchronization signal is used for adjusting the time of the second station, and the adjusted value is the average value of the vector difference of the first time difference information and the second time difference information;
step S102: the second time synchronization terminal also sends a second site time signal to the first site through the laser communication equipment according to the standard time received by the time service unit, and meanwhile, the first time synchronization terminal sends a first site time signal to the second site through the laser communication equipment according to the time information of the first site;
step S202: the time synchronization controller calculates and obtains a time synchronization signal sent to the first time synchronization terminal according to second time difference information, recorded by the second time synchronization terminal, of first site time transmitted by the first site and current second site standard time and first time difference information, recorded by the first time synchronization terminal, of second site time transmitted by the second site and current first site standard time;
step S203: the first station performs time synchronization by using the time synchronization unit according to the received time synchronization signal of the first time synchronization terminal.
2. The two-way time synchronization system based on free space laser communication as claimed in claim 1, wherein the time service unit comprises a GPS receiver and a high stable constant temperature crystal oscillator connected with the GPS receiver, and the high stable constant temperature crystal oscillator is acclimatized by the GPS receiver to obtain the high precision 1PPS time signal.
3. The two-way time synchronization system based on free-space laser communication of claim 1, wherein the first time synchronization terminal and the second time synchronization terminal further comprise a time encoder and a time decoder for encoding and decoding the transmitted time signal for time-encoded signal transmission.
4. A two-way time synchronization system based on free-space laser communication as claimed in claim 3 wherein said time encoded signal uses IRIG-B encoding to store the time signal.
5. The two-way time synchronization system based on free-space laser communication of claim 1, further comprising a time signal transceiver, wherein the time signal transceiver comprises a laser for transmitting a time signal and a photodetector for receiving the time signal, and the laser and the photodetector realize the split input and output of the time coding signal between the first site and the second site through a connecting circulator.
6. The two-way time synchronization system based on free-space laser communication according to claim 1, further comprising:
the signal modulation and demodulation units are respectively arranged between the time signal transceiver and the first time synchronization terminal as well as between the time signal transceiver and the second time synchronization terminal, so that the time coding signals are transmitted and received;
the time synchronization unit is arranged on the first time synchronization terminal and used for receiving the time synchronization signal, and the time service unit is arranged on the second time synchronization terminal and used for acquiring the standard time;
and the collimating lens is arranged between the laser and the photoelectric detector, so that the collimation of the laser communication beam is ensured.
7. A bidirectional time synchronization method based on free space laser communication is characterized by comprising the following sub-steps:
s101: the first time synchronization terminal sends a first site time signal to the second site through the laser communication equipment according to the standard time received by the time service unit, and meanwhile, the second time synchronization terminal sends a second site time signal to the first site through the laser communication equipment according to the time information of the second site;
s201: the time synchronization controller calculates and obtains a time synchronization signal sent to the second time synchronization terminal according to first time difference information, recorded by the first time synchronization terminal, of second site time transmitted by the second site and current first site standard time and second time difference information, received by the second time synchronization terminal, of first site time transmitted by the first site and current second site standard time;
s301: and the second station performs time synchronization by using the time synchronization unit according to the received time synchronization signal of the second time synchronization terminal.
8. The method according to claim 7, wherein the time synchronization signal is an average of vector differences between the first time difference information and the second time difference information for adjusting the time of the second station.
9. The method of claim 7, further comprising:
step S102: the second time synchronization terminal also sends a second site time signal to the first site through the laser communication equipment according to the standard time received by the time service unit, and meanwhile, the first time synchronization terminal sends a first site time signal to the second site through the laser communication equipment according to the time information of the first site;
step S202: the time synchronization controller calculates and obtains a time synchronization signal sent to the first time synchronization terminal according to second time difference information, recorded by the second time synchronization terminal, of first site time transmitted by the first site and current second site standard time and first time difference information, recorded by the first time synchronization terminal, of second site time transmitted by the second site and current first site standard time;
step S203: the first station performs time synchronization by using the time synchronization unit according to the received time synchronization signal of the first time synchronization terminal.
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| CN114710227B (en) * | 2022-04-27 | 2024-09-20 | 四川阿秒科技有限公司 | Free space time synchronization method based on natural light transmission |
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