CN112968746A - Satellite-ground communication synchronous capturing method and device based on position and Doppler information - Google Patents
Satellite-ground communication synchronous capturing method and device based on position and Doppler information Download PDFInfo
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- H04J3/0635—Clock or time synchronisation in a network
- H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/13—Receivers
- G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
- G01S19/27—Acquisition or tracking or demodulation of signals transmitted by the system creating, predicting or correcting ephemeris or almanac data within the receiver
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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
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- G01S19/29—Acquisition or tracking or demodulation of signals transmitted by the system carrier including Doppler, related
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- 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
- G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
- G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
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- G—PHYSICS
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- 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
- G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
- G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/42—Determining position
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- H—ELECTRICITY
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- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
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- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18513—Transmission in a satellite or space-based system
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- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
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- H04B7/185—Space-based or airborne stations; Stations for satellite systems
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Abstract
The invention provides a satellite-ground communication synchronous acquisition method and device based on position and Doppler information. In the first step, the ground terminal blindly captures a pilot signal, and executes the second step after success; in the second step, the ground terminal demodulates the broadcast data, obtains the satellite ephemeris, and updates the local parameter, then carry out the third step; in the third step, the ground terminal calculates and generates the optimal transmitting time and the used spread spectrum code according to the three parameters of the local position, the satellite position and the self address; in the fourth step, the ground terminal calculates the position of the satellite according to the transmitting time, and further calculates the satellite-ground distance according to the signal delay, thereby calculating the Doppler information; in the fifth step, before reaching the transmitting time, the time quantity in advance is calculated according to the delay time, the time is appointed in advance through the reverse channel, and the ground terminal bursts data according to the time after the appointed time in advance.
Description
Technical Field
The invention belongs to the field of satellite communication, and particularly relates to a satellite-ground communication synchronous capturing method and device based on position and Doppler information, which can be used for synchronization between satellite loads and ground terminals in various application scenes.
Background
Satellite communication is a microwave relay communication method implemented by using a communication satellite as a relay station. For military and low-rate, small-capacity satellite communication systems, Code Division Multiple Access (CDMA) spread spectrum communication regimes, or assisted by FDMA and TDMA, are commonly employed. CDMA has the advantages of strong anti-interference capability, small signal power spectral density and good concealment. However, the satellite communication system is subject to transmission loss, antenna gain of the mobile remote station and other factors, and the signal is weak. Under weak signal conditions, the receiver of the CDMA system has difficulty synchronizing the pseudo-random code. To improve the receiver sensitivity, methods of extending the coherent integration time and increasing the number of non-coherent integrations are generally adopted.
At present, a satellite navigation time service is adopted to correct a local clock to obtain a high-precision clock and a method for realizing time synchronization through a time transmission technology is adopted. The method only aims at the calibration of the local clock, so that the high-precision local clock is obtained or the local clock is synchronized with the time of the satellite navigation time service system. For a communication system, due to transmission delay, particularly satellite communication, uplink and downlink links are needed in a signal propagation process, the transmission delay is large, links generating errors (satellite drift, equipment delay, processing delay and the like) are more, only synchronization between local time and time of a satellite navigation time service system is established, specific time when a transmitted signal reaches a receiving end through a satellite-ground link is still uncertain, propagation time errors of multiple links need to be corrected, and otherwise, a scheme of directly synchronizing a local clock by utilizing satellite navigation time service cannot be directly used for synchronization of spread spectrum signal pseudo codes.
Disclosure of Invention
The technical problem to be solved by the present invention is to provide a satellite-ground communication synchronous capturing device based on position and doppler information, aiming at the above defects in the prior art, so as to solve the technical problem that propagation time errors of a plurality of links need to be corrected because the traditional synchronous signal is an uncertain quantity.
According to the invention, the method for synchronously acquiring the satellite-ground communication based on the position and the Doppler information is provided, which is used for synchronizing the satellite-ground communication signals in the satellite communication according to the Doppler information generated by the relative position and the relative motion between the interplanetals and between the satellites-ground, and comprises the following steps:
in the first step, the ground terminal blindly captures a pilot signal, and executes the second step after success;
in the second step, the ground terminal demodulates the broadcast data, obtains the satellite ephemeris, and updates the local parameter, then carry out the third step;
in the third step, the ground terminal calculates and generates the optimal transmitting time and the used spread spectrum code according to the three parameters of the local position, the satellite position and the self address;
in the fourth step, the ground terminal calculates the position of the satellite according to the transmitting time, and further calculates the satellite-ground distance according to the signal delay, thereby calculating the Doppler information;
in the fifth step, before reaching the transmitting time, the time quantity in advance is calculated according to the delay time, the time is appointed in advance through the reverse channel, and the ground terminal bursts data according to the time after the appointed time in advance.
Preferably, the second step and the third step together constitute a forward synchronization process.
Preferably, the fourth step and the fifth step together constitute a reverse synchronization process.
Preferably, the doppler information includes doppler frequency offset, phase offset and frequency change rate.
According to the invention, there is also provided a satellite-ground communication synchronization acquisition device based on position and doppler information, which is used for synchronizing satellite-ground communication signals in satellite communication according to doppler information generated by interplanetary and interplanetary relative position and relative motion, and comprises: the device comprises a controller, synchronous hardware, a digital-to-analog converter (DAC) circuit and a clock signal generator;
the controller comprises a message control circuit and a data link control circuit; the message control circuit is used for communicating with other parts of the satellite-ground communication synchronous capturing device through a network interface, and a message head and a message tail are added into the message control circuit during communication to form message information; the data link control circuit is used for controlling wireless link communication between the satellite and the ground and between the satellites;
the synchronization circuit includes: a standard time source, a Doppler signal filter and a local pseudo-random code time manager;
the standard time source forms a satellite ephemeris through communication among a plurality of satellites according to a ground time service source;
the Doppler signal filter generates Doppler information of relative movement for controlling synchronization according to positions among different satellites, relative positions of the satellites and the ground and movement speed based on a satellite ephemeris formed by a standard time source;
the digital-to-analog converter DAC circuit is used for converting the digital signal output by the Doppler signal filter into an analog signal;
the clock signal generator and the clock of the local crystal oscillator form a synchronous clock signal under the control of the analog signal converted by the high-resolution DAC circuit, and the synchronous clock signal is transmitted to the local pseudo random code time manager;
the local pseudo-random code time manager generates a local pseudo-random code and a spread code according to the relative position of the local pseudo-random code and the system, calculates and obtains the optimal synchronization time according to the generated local pseudo-random code and spread code and a received synchronization clock signal, and sends the optimal synchronization time to a standard time source.
Preferably, the doppler information is obtained by measurement of a pseudorandom sequence.
Preferably, the formed synchronous clock signal is clocked out as a synchronous frequency scale signal to the synchronized device.
According to the invention, there is also provided a satellite-ground communication synchronization acquisition device based on position and doppler information, which is used for synchronizing satellite-ground communication signals in satellite communication according to doppler information generated by interplanetary and interplanetary relative position and relative motion, and comprises:
the first device is used for receiving time information among satellites through an antenna to form a satellite ephemeris time source;
the second device is used as a central controller for executing state control of time service and synchronization;
the third device is used for detecting the time information of the detected end and detecting the detected time source;
the fourth device is used as a time source controller device and used for carrying out message interaction of synchronous information between the first device and the second device;
a fifth means as a message generating circuit for generating a message;
the sixth device is used for receiving network time signals of the ground time service center and adding the signals into the message generated by the fifth device to form an interactive message;
and the seventh device is used for performing conversion of the photoelectric signals to support interaction between the optical signals and the wireless signals and the timed system.
Preferably, the fourth device is state-controlled by the second device as a central controller.
Preferably, the message header and the message tail of the message generated by the fifth device are identified by fixed bits, and the intermediate information is generated by encoding operation.
The invention solves the technical problem that the propagation time errors of a plurality of links are needed to be corrected because the traditional synchronous signal is an uncertain quantity. The invention can reduce the frequency uncertainty of the on-satellite demodulation information, thereby obviously reducing the on-satellite despreading and demodulation burden; increasing user capacity on the reverse channel.
Drawings
A more complete understanding of the present invention, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:
fig. 1 schematically shows a general flowchart of a satellite-to-ground communication synchronization acquisition method based on location and doppler information according to a preferred embodiment of the present invention.
Fig. 2 schematically shows a functional block diagram of a satellite-to-ground communication synchronization acquisition apparatus based on location and doppler information according to a preferred embodiment of the present invention.
Fig. 3 is a hardware device diagram schematically illustrating a satellite-to-ground communication synchronization acquiring device based on location and doppler information according to a preferred embodiment of the present invention.
It is to be noted, however, that the appended drawings illustrate rather than limit the invention. It is noted that the drawings representing structures may not be drawn to scale. Also, in the drawings, the same or similar elements are denoted by the same or similar reference numerals.
Detailed Description
In order that the present disclosure may be more clearly and readily understood, reference will now be made in detail to the present disclosure as illustrated in the accompanying drawings.
A communication frequency of 300MHz may be used in the implementation example of the invention, but is not limited to this frequency, under which condition the doppler related information:
satellite-to-ground Doppler: (actually 10KHz, accounting for 5KHz frequency source offset);
satellite-to-ground doppler rate of change:
one, forward synchronous process
The downlink channel constructs a superframe by using GPS/BD-2 second pulse and time information and taking 60 second as an interval, and broadcasts full-network ephemeris and local satellite configuration information in a specific time slot of the superframe. And sending the downlink data in the designated downlink time slot.
The downlink can fully utilize pilot frequency and broadcast information, so that the acquisition, tracking and synchronization performances of the downlink are ideal.
Two, reverse synchronous process
The main goals of reverse synchronization include:
(1) the frequency uncertainty of the on-satellite demodulation information is reduced, and therefore the on-satellite despreading and demodulation burden is obviously reduced.
(2) Increasing user capacity on the reverse channel;
the first goal is the major burden on the satellite, for 15KHz doppler, the processing cost is high even with a long enough pilot sequence (reverse pilot) in case of satellite-to-ground time synchronization failure.
By the effective technical means of the invention, the satellite frequency searching range is compressed to 4KHz, and the capture time is improved by 3 times under the condition of the same algorithm. This is very advantageous for burst channels.
The invention aims to adopt a reverse synchronization method based on GPS/BD-2+ broadcast information + pilot frequency measurement. For example, the specific implementation method may include:
(1) the fixed terminal determines the position of the fixed terminal through (GPS/BD-2) network access for the first time. The mobile terminal acquires the position of the mobile terminal in real time. And corrects the local time and time accuracy based on the navigation data.
(2) The terminal tries to acquire the satellite broadcast frame after being powered on (low power acquisition strategy for pilots). Acquiring a current satellite ephemeris (simultaneously acquiring other satellite ephemeris of the whole network) after the acquisition is successful, and calculating the satellite position, the relative distance and the relative speed according to the satellite ephemeris at the subsequent time (the validity period is 10 minutes);
(3) on the basis that the relative distance and the relative speed are calculated accurately, the terminal calculates accurate transmission frame deviation, transmission time and transmission power in a specified time slot according to the reverse channel frequency spectrum configuration, the code word configuration and the time slot configuration in the broadcast information (the frequency/time slot/spread spectrum code is randomly selected to ensure that the frequency of a signal received by the satellite is within the range of 3 KHz), and the satellite can be ensured to demodulate quickly.
Third, synchronous flow and method
The synchronization process involves three calculations:
1) calculating the satellite position and Doppler at the appointed time according to the satellite ephemeris;
2) calculating a satellite-ground distance for a specified time from the satellite position and the terminal position (local GPS);
3) a plurality of parameters are used as random numbers to calculate the optimal time slot for transmission.
In particular, fig. 1 schematically shows a general flow chart of a satellite-to-ground communication synchronization acquisition method based on location and doppler information according to a preferred embodiment of the present invention. The method can be used for synchronizing the inter-satellite-ground communication signals in satellite communication according to Doppler information generated by inter-satellite and inter-satellite-ground relative position and relative motion. The synchronous processing method is respectively executed on a forward channel and a reverse channel, and the synchronous processing between the load and the ground terminal is completed. The following steps will be described in detail with reference to fig. 1, taking three calculations for completing synchronization as an example.
As shown in fig. 1, the method for acquiring synchronization of satellite-to-ground communication based on location and doppler information according to the preferred embodiment of the present invention comprises:
in a first step 101, the ground terminal blindly acquires the pilot signal, and after success, performs a second step 102.
In a second step 102 (both the second step and the third step 103 belong to the forward synchronization process), the ground terminal demodulates the broadcast data, acquires the satellite ephemeris and updates the local parameters, and then executes the third step 103.
In a third step 103, the ground terminal calculates and generates an optimal transmission time and a used spreading code according to three parameters of a local position, a satellite position and a self address. And the ground terminal executes the process to complete the forward synchronization of the satellite to the ground.
In a fourth step 104 (which together with the fifth step 105 forms a reverse synchronization process), the ground terminal calculates the position of the satellite accurately according to the transmission time, and further calculates the satellite-ground distance according to the signal delay, so as to calculate doppler information, for example, the doppler information includes information such as doppler frequency offset, phase offset, and frequency change rate.
In a fifth step 105, before the transmission time is reached, an advance time is calculated according to the delay time, the reverse channel is advanced by a specified time, and the ground terminal bursts data at a time after the specified time. The reverse synchronous processing process is completed through the steps.
Fig. 2 schematically shows a functional block diagram of a satellite-to-ground communication synchronization acquisition apparatus based on location and doppler information according to a preferred embodiment of the present invention.
As shown in fig. 2, the satellite-to-ground communication synchronization acquiring apparatus based on location and doppler information according to the preferred embodiment of the present invention includes: controller 21, synchronization hardware 22, digital-to-analog converter DAC circuitry, and clock signal generator 232. For example, the controller may employ a general purpose Digital Signal Processor (DSP), and the synchronization hardware may be implemented by FPGA programming. The implementation method is based on a general-purpose chip, but is not limited to the above manner, and for example, an application-specific integrated circuit may be designed to implement the implementation method.
The message control circuit 201 is used for communicating with other parts of the satellite-ground communication synchronous capturing device through a network interface, and a message header and a message tail are added to the message control circuit during communication to form message information.
Data link control circuitry 202 is used to control wireless link communications between the satellite and the ground and between satellites.
The synchronization circuit 22 includes: a standard time source 221, a doppler signal filter 222, and a local pseudorandom code time manager 223.
The standard time source 221 forms satellite ephemeris via communications between multiple satellites based on a ground time service.
The doppler signal filter 222 generates doppler information of relative motion, such as doppler frequency offset, phase offset, frequency change rate, etc., according to the position between different satellites and the relative position and motion velocity between the satellites and the ground based on the satellite ephemeris formed by the standard time source 221. Such doppler information may be obtained by measurement of a pseudorandom sequence. The Doppler signal filter obtains the information of the needed Doppler frequency offset and phase offset for controlling synchronization.
The digital-to-analog converter DAC circuit is, for example, a high resolution DAC circuit 231 for converting the digital signal output from the doppler signal filter 222 into an analog signal.
The clock signal generator 232 forms a synchronous clock signal together with the clock of the local crystal oscillator under the control of the analog signal converted by the high resolution DAC circuit 231 and transfers the synchronous clock signal to the local pseudo random code time manager 223, and the formed synchronous clock signal (standard timing signal), i.e., a synchronous frequency scale signal, is outputted to the synchronized device at a timing.
The local pseudo random code time manager 223 generates local pseudo random codes, spreading codes, etc. according to the relative positions of the local and system, calculates an optimal synchronization time according to the information and the received synchronization clock signal, and transmits the optimal synchronization time to the standard time source 221. The standard time source is typically broadcast via ephemeris in a GPS or beidou system for time service to the satellite system.
The hardware device is a standard time source 221, a Doppler signal filter 222, a high-resolution DAC circuit 231, a clock signal 232 and a local pseudo random code time manager 223 which form a closed loop system connected by signal lines.
Fig. 3 is a hardware device diagram schematically illustrating a satellite-to-ground communication synchronization acquiring device based on location and doppler information according to a preferred embodiment of the present invention. The control module therein can be seen as a refinement of the controller circuit of fig. 2. The synchronization device adopts a mode of satellite load and ground terminal message interaction to carry out time service.
The first device 301 receives time information between satellites through an antenna to form a satellite ephemeris time source;
the second device 302 is used as a central controller for executing state control of time service and synchronization;
the third device 303 is used for detecting the time information of the detected end and performing the detected time source detection. For example, the satellite payload detects the time source information of the ground terminal through the time delay message.
The fourth device 304 is used as a time source controller device for performing message interaction of synchronization information between the first device 301 and the second device 302, wherein the second device 302 serving as a central controller performs state control on the fourth device;
the fifth means 305 is used as a message generating circuit for generating a message, where the header and the trailer of the generated message are identified by fixed bits, and the intermediate information is generated through encoding operation. The message generating circuit generates a message according to the control of the time source controller. The message head and tail of the time source issued message are fixed, and the intermediate information is generated by coding. This can be achieved by hardware encoding of registers.
The sixth device 306 is configured to receive network time signals of the ground time service center, and add the network time signals to the message generated by the fifth device 305 to form an interactive message.
The seventh means 307 is used to perform the conversion of the optical-electrical signal to support the interaction between the optical signal and the wireless signal and the timed system.
Compared with the prior art, the invention has at least the following advantages:
1. the satellite de-spread demodulation method has the advantages that the application range is wide, and due to the adoption of the satellite ephemeris and the Doppler information, the frequency uncertainty of the satellite demodulation information can be reduced, so that the satellite de-spread demodulation burden is remarkably reduced.
2. The method has low implementation cost and high reliability, and can be realized by programming by adopting a general FPGA or DSP. The reliability is higher due to the adoption of a mature device;
3. the synchronous capability is strong, and the capture time is improved by 3 times. This is very beneficial to the burst channel, and improves the overall synchronization performance;
4. the expansibility is high, and good expansibility is achieved due to the adoption of the satellite-ground cooperation algorithm. Increasing user capacity on the reverse channel.
It should be noted that the terms "first", "second", "third", and the like in the description are used for distinguishing various components, elements, steps, and the like in the description, and are not used for indicating a logical relationship or a sequential relationship between the various components, elements, steps, and the like, unless otherwise specified.
It is to be understood that while the present invention has been described in conjunction with the preferred embodiments thereof, it is not intended to limit the invention to those embodiments. It will be apparent to those skilled in the art from this disclosure that many changes and modifications can be made, or equivalents modified, in the embodiments of the invention without departing from the scope of the invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention, unless the contents of the technical solution of the present invention are departed.
Claims (10)
1. A satellite-ground communication synchronous acquisition method based on position and Doppler information is used for synchronizing satellite-ground communication signals in satellite communication according to Doppler information generated by interplanetary and relative position and relative motion between satellites and ground, and is characterized by comprising the following steps:
in the first step, the ground terminal blindly captures a pilot signal, and executes the second step after success;
in the second step, the ground terminal demodulates the broadcast data, obtains the satellite ephemeris, and updates the local parameter, then carry out the third step;
in the third step, the ground terminal calculates and generates the optimal transmitting time and the used spread spectrum code according to the three parameters of the local position, the satellite position and the self address;
in the fourth step, the ground terminal calculates the position of the satellite according to the transmitting time, and further calculates the satellite-ground distance according to the signal delay, thereby calculating the Doppler information;
in the fifth step, before reaching the transmitting time, the time quantity in advance is calculated according to the delay time, the time is appointed in advance through the reverse channel, and the ground terminal bursts data according to the time after the appointed time in advance.
2. The method of claim 1, wherein the second and third steps together form a forward synchronization process.
3. The method for acquiring synchronization of satellite-to-ground communication according to claim 1 or 2, wherein the fourth step and the fifth step together form a reverse synchronization process.
4. The method of claim 1 or 2, wherein the Doppler information comprises Doppler frequency offset, phase offset and frequency change rate.
5. A satellite-ground communication synchronization acquisition apparatus based on position and doppler information, for synchronizing satellite-ground communication signals in satellite communication according to doppler information generated by interplanetary and interplanetary relative position and relative motion, comprising:
the device comprises a controller, synchronous hardware, a digital-to-analog converter (DAC) circuit and a clock signal generator;
the controller comprises a message control circuit and a data link control circuit; the message control circuit is used for communicating with other parts of the satellite-ground communication synchronous capturing device through a network interface, and a message head and a message tail are added into the message control circuit during communication to form message information; the data link control circuit is used for controlling wireless link communication between the satellite and the ground and between the satellites;
the synchronization circuit includes: a standard time source, a Doppler signal filter and a local pseudo-random code time manager;
the standard time source forms a satellite ephemeris through communication among a plurality of satellites according to a ground time service source;
the Doppler signal filter generates Doppler information of relative movement for controlling synchronization according to positions among different satellites, relative positions of the satellites and the ground and movement speed based on a satellite ephemeris formed by a standard time source;
the digital-to-analog converter DAC circuit is used for converting the digital signal output by the Doppler signal filter into an analog signal;
the clock signal generator and the clock of the local crystal oscillator form a synchronous clock signal under the control of the analog signal converted by the high-resolution DAC circuit, and the synchronous clock signal is transmitted to the local pseudo random code time manager;
the local pseudo-random code time manager generates a local pseudo-random code and a spread code according to the relative position of the local pseudo-random code and the system, calculates and obtains the optimal synchronization time according to the generated local pseudo-random code and spread code and a received synchronization clock signal, and sends the optimal synchronization time to a standard time source.
6. The device of claim 5, wherein the Doppler information is obtained by pseudo-random sequence measurement.
7. The device according to claim 5 or 6, wherein the formed synchronous clock signal is outputted to the synchronized device as a synchronous frequency scale signal.
8. A satellite-ground communication synchronization acquisition apparatus based on position and doppler information, for synchronizing satellite-ground communication signals in satellite communication according to doppler information generated by interplanetary and interplanetary relative position and relative motion, comprising:
the first device is used for receiving time information among satellites through an antenna to form a satellite ephemeris time source;
the second device is used as a central controller for executing state control of time service and synchronization;
the third device is used for detecting the time information of the detected end and detecting the detected time source;
the fourth device is used as a time source controller device and used for carrying out message interaction of synchronous information between the first device and the second device;
a fifth means as a message generating circuit for generating a message;
the sixth device is used for receiving network time signals of the ground time service center and adding the signals into the message generated by the fifth device to form an interactive message;
and the seventh device is used for performing conversion of the photoelectric signals to support interaction between the optical signals and the wireless signals and the timed system.
9. The device of claim 8, wherein the fourth device is state-controlled by the second device as a central controller.
10. The device for synchronous acquisition of satellite-ground communication based on location and doppler information according to claim 8 or 9, wherein the message header and message tail of the message generated by the fifth device are identified by fixed bits, and the middle information is generated by encoding operation.
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