CN112291026B - Clock deviation correction method and device based on guard interval and computer readable medium - Google Patents

Clock deviation correction method and device based on guard interval and computer readable medium Download PDF

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CN112291026B
CN112291026B CN202011142372.XA CN202011142372A CN112291026B CN 112291026 B CN112291026 B CN 112291026B CN 202011142372 A CN202011142372 A CN 202011142372A CN 112291026 B CN112291026 B CN 112291026B
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signal
clock
party
target
baseband
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CN112291026A (en
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郑磊
张宝功
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Beijing Kongling Nettech Technology Co ltd
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Beijing Kongling Nettech Technology Co ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/0635—Clock or time synchronisation in a network
    • H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
    • H04J3/0644—External master-clock
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/0635—Clock or time synchronisation in a network
    • H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L7/00—Arrangements for synchronising receiver with transmitter
    • H04L7/0016—Arrangements for synchronising receiver with transmitter correction of synchronization errors
    • H04L7/0033—Correction by delay
    • H04L7/0037—Delay of clock signal

Abstract

The invention provides a clock deviation correction method and a device based on a guard interval, which relate to the technical field of satellite communication and comprise the following steps: before sending or receiving a baseband signal, acquiring a clock signal of a third party, and determining the clock signal of the third party as a reference signal; then calculating the clock deviation between the target party and the third party based on the reference signal; and finally, adjusting the length of a guard interval of the baseband signal based on the clock deviation so that the difference value between the time for the target party to send or receive the baseband signal and the reference signal is smaller than a preset time difference value. The invention corrects the time of the target party for sending or receiving the baseband signal by adjusting the length of the guard interval of the baseband signal, so that the difference value between the time of the target party for sending or receiving the baseband signal and the reference signal is smaller than the preset time difference value, the invention is suitable for the scene that the target party can not directly adjust the clock source, and has the advantages of simple clock deviation correction mode and convenient engineering realization.

Description

Clock deviation correction method and device based on guard interval and computer readable medium
Technical Field
The invention relates to the technical field of satellite communication, in particular to a clock deviation correction method and device based on a guard interval.
Background
In a communication system, a time reference which can be accurately and stably established by a transmitter and a receiver is the most basic guarantee for establishing a communication link, and the establishment of the time reference by the transmitter and the receiver generally has the following two modes: one is that the receiving side locks with the transmitting side by a synchronization signal or the like in the communication signal; the other is realized by the way that the transmitting and receiving parties lock the third party time reference source together. Therefore, the two existing clock skew correction methods realize clock skew correction by adjusting a local clock source. However, in some specific cases, the transceiver and the transmitter cannot perform the operation of adjusting the local clock source, so the existing clock skew correction method is no longer applicable in such cases.
Disclosure of Invention
The invention aims to provide a clock skew correction method and a device based on a guard interval, so as to solve the technical problem that the existing clock skew correction method is not applicable under the condition that a transmitting party and a receiving party in the prior art cannot perform the operation of adjusting a local clock source.
In a first aspect, the present invention provides a method for correcting a clock skew based on a guard interval, including: before sending or receiving a baseband signal, acquiring a clock signal of a third party, and determining the clock signal of the third party as a reference signal; calculating a clock offset between a target party and the third party based on the reference signal; the target party is a beam hopping satellite communication load or a satellite terminal, the beam hopping satellite communication load and the satellite terminal are respectively provided with a baseband digital signal processing unit, and the baseband digital signal processing unit adopts a target clock to provide a clock signal of the target party at an ADC/DAC sampling point; adjusting the length of a guard interval of the baseband signal based on the clock deviation so that the difference between the time of sending or receiving the baseband signal by the target party and the reference signal is smaller than a preset time difference; and the guard interval is arranged between every two adjacent signal frames in the baseband signal.
Further, when the target party is a beam hopping satellite communication load, calculating a clock offset between the target party and the third party based on the reference signal, including: acquiring a first clock signal; wherein the first clock signal is a clock signal of the beam hopping satellite communication load at an ADC/DAC sampling point; calculating a first clock offset between the beam hopping satellite communications payload and the third party based on the first clock signal and the reference signal.
Further, when the target party is a satellite terminal, calculating a clock offset between the target party and the third party based on the reference signal, including: acquiring a second clock signal; the second clock signal is a clock signal of the satellite terminal at an ADC/DAC sampling point; calculating a second clock offset between the satellite terminal and the third party based on the second clock signal and the reference signal.
Further, calculating a first clock offset between the beam hopping satellite communications payload and the third party based on the first clock signal and the reference signal, comprising: comparing the first clock signal with the reference signal to obtain a first comparison result; determining the first comparison result as a first clock offset between the beam hopping satellite communications payload and the third party.
Further, calculating a second clock bias between the satellite terminal and the third party based on the second clock signal and the reference signal, comprising: comparing the second clock signal with the reference signal to obtain a second comparison result; determining the second comparison result as a second clock offset between the satellite terminal and the third party.
Further, adjusting the length of the guard interval of the baseband signal based on the clock offset includes: and feeding back the clock deviation to the baseband digital signal processing unit of the target party so as to enable the baseband digital signal processing unit of the target party to adjust the length of the guard interval of the baseband signal in a mode of increasing or decreasing the number of sampling points in the guard interval of the baseband signal.
Further, the reference signal is a 1PPS signal.
In a second aspect, the present invention provides a clock skew correction apparatus based on a guard interval, including: the device comprises an acquisition determining unit, a processing unit and a processing unit, wherein the acquisition determining unit is used for acquiring a clock signal of a third party before transmitting or receiving a baseband signal and determining the clock signal of the third party as a reference signal; a calculation unit for calculating a clock skew between a target party and the third party based on the reference signal; the target party is a beam hopping satellite communication load or a satellite terminal, the beam hopping satellite communication load and the satellite terminal are respectively provided with a baseband digital signal processing unit, and the baseband digital signal processing unit adopts a target clock to provide a clock signal of the target party at an ADC/DAC sampling point; an adjusting unit, configured to adjust a length of a guard interval of the baseband signal based on the clock offset, so that a difference between a time when the target sends or receives the baseband signal and the reference signal is smaller than a preset time difference; and the guard interval is arranged between every two adjacent signal frames in the baseband signal.
In a third aspect, the present invention further provides an electronic device, including a memory and a processor, where the memory stores a computer program executable on the processor, and the processor executes the computer program to implement the steps of the guard interval-based clock skew correction method.
In a fourth aspect, the present invention also provides a computer readable medium having a non-volatile program code executable by a processor, wherein the program code causes the processor to execute the guard interval based clock skew correction method.
The invention provides a clock deviation correction method and a device based on a guard interval, comprising the following steps: before sending or receiving a baseband signal, acquiring a clock signal of a third party, and determining the clock signal of the third party as a reference signal; then calculating the clock deviation between the target party and the third party based on the reference signal; the target party is a beam hopping satellite communication load or a satellite terminal, the beam hopping satellite communication load and the satellite terminal are respectively provided with a baseband digital signal processing unit, and the baseband digital signal processing unit adopts a target clock to provide a clock signal of the target party at an ADC/DAC sampling point; finally, the length of a guard interval of the baseband signal is adjusted based on the clock deviation, so that the difference value between the time for the target party to send or receive the baseband signal and the reference signal is smaller than a preset time difference value; and a guard interval is arranged between every two adjacent signal frames in the baseband signal. The invention corrects the time of the target party for sending or receiving the baseband signal by adjusting the length of the guard interval of the baseband signal, so that the difference value between the time of the target party for sending or receiving the baseband signal and the reference signal is smaller than the preset time difference value, the invention is suitable for the scene that the target party can not adjust the local clock source, and has the advantages of simple clock deviation correction mode and convenient engineering realization.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a flowchart of a guard interval-based clock skew correction method according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a manner in which the satellite platform provides 1PPS signals to the communication load subsystem and a signal processing process performed by the communication load subsystem;
FIG. 3 is a schematic diagram of sample point clock versus 1PPS signal;
FIG. 4 is a diagram of a signal frame and a guard interval;
fig. 5 is a schematic structural diagram of a guard interval-based clock skew correction apparatus according to an embodiment of the present invention.
Icon:
11-an acquisition determination unit; 12-a calculation unit; 13-an adjustment unit.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In a communication system, a time reference which can be accurately and stably established by a transmitter and a receiver is the most basic guarantee for establishing a communication link, and the establishment of the time reference by the transmitter and the receiver generally has the following two modes: one is that the receiving side locks with the transmitting side by a synchronization signal or the like in the communication signal; the other is realized by the way that the transmitting and receiving parties lock the third party time reference source together.
In a satellite communication system, both a transmitting party and a receiving party receive GNSS signals conditionally, not only can position information of the transmitting party and the receiving party can obtain accurate and stable third-party time reference, and the transmitting party and the receiving party are locked with the GNSS signals together, so that the accurate and stable time reference of the transmitting party and the receiving party can be conveniently established. In the NGSO satellite communication constellation system, since the distance between the transmitting and receiving parties is long and the distance change is large during the movement of the satellite, it is the most convenient method to acquire the time reference by using the GNSS signal.
In a communication satellite, a load subsystem and an on-satellite clock source are relatively independent, the on-satellite clock source can provide a standard reference clock for the load subsystem, and the load subsystem can be corrected by using the reference clock, so that the time reference of the load subsystem and the standard time reference provided by the system can be locked, and the standard time reference is usually provided in a 1PPS (first-second-third-party service) form. In the prior art, a more accurate reference source (a first network element) is simultaneously compared with a second network element to be synchronized, and the second network element to be synchronized is simultaneously compared with a third-party reference signal, so as to obtain time deviation correction information.
However, in some specific cases, the transmitter and the receiver cannot perform the local clock adjustment operation, and thus, in such a case, the conventional clock skew correction method is no longer applicable.
Accordingly, an object of the present invention is to provide a clock skew correction method and apparatus based on a guard interval, which can alleviate the technical problem that the conventional clock skew correction method is no longer applicable when both the transmitter and the receiver cannot perform a local clock adjustment operation in the prior art.
For the convenience of understanding the present embodiment, a method for correcting a clock skew based on a guard interval disclosed in the present embodiment is first described in detail.
Example 1:
in accordance with an embodiment of the present invention, there is provided an embodiment of a guard interval based clock skew correction method, it should be noted that the steps illustrated in the flowchart of the accompanying drawings may be performed in a computer system such as a set of computer executable instructions, and that while a logical order is illustrated in the flowchart, in some cases the steps illustrated or described may be performed in an order different than here.
Fig. 1 is a flowchart of a guard interval-based clock skew correction method according to an embodiment of the present invention, as shown in fig. 1, the method includes the following steps:
step S101, before transmitting or receiving the baseband signal, acquiring a clock signal of a third party, and determining the clock signal of the third party as a reference signal.
In the embodiment of the present invention, the communication satellite system is composed of a satellite platform (or called platform) and a communication load subsystem, wherein the satellite platform can be used as a third party to provide a 1PPS standard time signal in the present application. The 1PPS standard time signal, referred to as the 1PPS signal for short, may be a reference signal in this application. In addition, the platform can provide guarantee of the on-orbit operation of the whole satellite, such as energy, measurement and control, attitude/orbit control and the like, besides providing 1PPS standard time signals.
The present application is applied to the beam hopping satellite communication load or the satellite terminal in step S102 described below, and can acquire the 1PPS signal regardless of the beam hopping satellite communication load or the satellite terminal.
In this application, since the above-mentioned beam hopping satellite communication load may be referred to as a communication load subsystem, or referred to as a load subsystem, the satellite platform provides 1PPS signals for the beam hopping satellite communication load, which is equivalent to the satellite platform providing 1PPS signals for the communication load subsystem. The manner in which the satellite platform provides 1PPS signals to the communication load subsystem (i.e., the load subsystem in fig. 2) and the processing of the signals by the communication load subsystem are shown in fig. 2. It should be noted that, in fig. 2, the satellite platform transmits the 1PPS main signal and the 1PPS signal, and two 1PPS signals are provided for the 1PPS main signal and the 1PPS signal, so that the reliability of signal transmission can be improved.
Step S102, calculating the clock deviation between the target party and the third party based on the reference signal.
The target party is a beam hopping satellite communication load or a satellite terminal, the beam hopping satellite communication load and the satellite terminal are respectively provided with a baseband digital signal processing unit, and the baseband digital signal processing unit adopts a target clock to provide a clock signal of the target party at an ADC/DAC sampling point. The target clock may refer to a local clock on the target side. The baseband digital signal processing unit may refer to the communication subsystem baseband digital signal processing unit in fig. 2. Because the communication is bidirectional, when the beam hopping satellite communication load is a sender, the satellite terminal is a receiver; and when the satellite terminal is the sender, the beam hopping satellite communication load is the receiver. And the beam hopping satellite communication load and the satellite terminal respectively carry out respective clock deviation correction, and the two clock deviation correction processes are not influenced by each other.
Step S103, adjusting the length of the guard interval of the baseband signal based on the clock offset, so that the difference between the time when the target sends or receives the baseband signal and the reference signal is smaller than the preset time difference.
And a guard interval is arranged between every two adjacent signal frames in the baseband signal. The load subsystem has its own clock source, the frequency accuracy of the common crystal oscillator is less than 0.1PPM, the temperature stability is less than 0.3PPM, the annual aging rate index is less than 0.5PPM, and the short-time stability can reach 10-12. The jitter of the 1PPS signal provided by the satellite platform can be plus or minus 50ns, and can be controlled within plus or minus 20ns after correction.
When a satellite broadband communication system (i.e., the above communication satellite system) adopts the SC-FDMA technology system of 5G, in order to improve the spectrum utilization rate of a channel, the Cyclic Prefix (CP) should be designed within the synchronization maintaining deviation, and the smaller the CP, the better, such as when the CP is designed to be 280nS, this requires that the uplink timing accuracy (i.e., the accuracy after clock deviation correction) is better than the value. The uplink timing precision includes but is not limited to: distance estimation errors caused by distance changes between the satellite terminal and the satellite, engineering deviation realized by the satellite terminal and the satellite load, and timing deviation of the satellite terminal and the satellite load.
After the frequency stability and the temperature stability of the crystal oscillator are comprehensively considered, the time deviation of 400nS is caused by 1 second according to the comprehensive stability of the crystal oscillator of 0.4PPM, if no measure is taken, and the deviation is far beyond the requirement of system design and must be calibrated by using a 1PPS signal provided by a satellite platform. That is, the 1PPS signal plays a role of clock calibration in the above step S102.
In steps S101 to S103 in the embodiment of the present invention, before transmitting or receiving a baseband signal, a clock signal of a third party is obtained, and the clock signal of the third party is determined as a reference signal; then calculating the clock deviation between the target party and the third party based on the reference signal; the target party is a beam hopping satellite communication load or a satellite terminal, the beam hopping satellite communication load and the satellite terminal are respectively provided with a baseband digital signal processing unit, and the baseband digital signal processing unit adopts a target clock to provide a clock signal of the target party at an ADC/DAC sampling point; finally, the length of a guard interval of the baseband signal is adjusted based on the clock deviation, so that the difference value between the time for the target party to send or receive the baseband signal and the reference signal is smaller than a preset time difference value; and a guard interval is arranged between every two adjacent signal frames in the baseband signal. The embodiment of the invention corrects the time for the target to send or receive the baseband signal by adjusting the length of the guard interval of the baseband signal, so that the difference value between the time for the target to send or receive the baseband signal and the reference signal is smaller than the preset time difference value, the method and the device are suitable for the scene that the target cannot adjust the local clock source, and have the advantages of simple clock deviation correction mode and convenience for engineering realization.
In an optional embodiment, when the target party is a beam hopping satellite communication load, step S102, calculating a clock offset between the target party and a third party based on the reference signal, includes steps S201 to S202, where step S201 acquires a first clock signal; the first clock signal is a clock signal of a hopping beam satellite communication load at an ADC/DAC sampling point; step S202, calculating a first clock deviation between the beam hopping satellite communication load and a third party based on the first clock signal and the reference signal.
In an alternative embodiment, the step S202 of calculating a first clock offset between the beam-hopping satellite communication payload and a third party based on the first clock signal and the reference signal includes steps S301 to S302, where: step S301, comparing the first clock signal with a reference signal to obtain a first comparison result; step S302, determining the first comparison result as a first clock deviation between the beam hopping satellite communication load and a third party.
In an alternative embodiment, when the target party is a satellite terminal, step S102 is to calculate a clock offset between the target party and a third party based on the reference signal, and includes steps S203 to S204, where: step S203, acquiring a second clock signal; the second clock signal is a clock signal of the satellite terminal at an ADC/DAC sampling point; step S204, calculating a second clock deviation between the satellite terminal and a third party based on the second clock signal and the reference signal.
In an alternative embodiment, the step S204 of calculating a second clock offset between the satellite terminal and a third party based on the second clock signal and the reference signal includes: step S303 to step S304, wherein: step S303, comparing the second clock signal with the reference signal to obtain a second comparison result; step S304, determining the second comparison result as a second clock offset between the satellite terminal and a third party.
It should be noted that the above-described steps S201 to S202 are similar to the flow of steps S203 to S204. Similarly, the above steps S301 to S302 are similar to the flows of steps S303 to S304.
In an alternative embodiment, the step S103 of adjusting the length of the guard interval of the baseband signal based on the clock offset includes: and feeding back the clock deviation to the target baseband digital signal processing unit so that the target baseband digital signal processing unit adjusts the length of the guard interval of the baseband signal in a mode of increasing or decreasing the number of sampling points in the guard interval of the baseband signal.
The baseband signal generated or received by the satellite communication system (i.e., the communication satellite system) will be finally presented as the baseband signal waveform in fig. 2 in the form of an ADC/DAC sampling point, which is the minimum time unit that the baseband signal waveform can recognize, so that the adjustment of clock synchronization at the ADC/DAC sampling point is the minimum amount of synchronization adjustment on the time axis, which is the smoothest adjustment manner. Illustratively, a schematic diagram of the sample point clock (i.e., the first clock signal or the second clock signal described above) compared to the 1PPS signal is shown in FIG. 3.
Assuming a satellite communications system with a sampling point clock of 2.4GSPS, the time interval of the sampling point is 0.4167nS, and correspondingly, one sampling point is increased or decreased, and the time adjustment is 0.4167nS, i.e., the deviation from the given 1PPS signal can be theoretically minimized to 10 nS-3PPM。
In the beam-hopping satellite communication system, the format of the signal frame is shown in fig. 4, when the transmitted or received signal frame is switched between different beams, a guard interval is designed between two adjacent signal frames (i.e. beam signal frames) in consideration of the switching time, as shown in fig. 4.
In the present embodiment, as shown in fig. 3, the clock/1 PPS offset comparator counts the clock signal by using the counter within a unit time of 1PPS, for example, 1 second, and the offset of the counter from the preset threshold is the timing offset signal (i.e., the above-mentioned first clock offset or second clock offset). For ease of engineering implementation, the clock signal in the clock/1 PPS offset comparator may also be derived from other clocks in the system that are locked to the sampling clock.
After obtaining the timing deviation signal, the baseband digital signal processing unit decomposes the timing deviation into a plurality of GPs according to the positive and negative of the timing deviation and the amount of the timing deviation, and adjusts the timing deviation of the system by increasing (negative deviation) or decreasing (positive deviation) the number of sampling points in the GPs.
The embodiment of the invention fully utilizes the guard interval GP in the satellite communication system of the hopping beam, takes the sampling clock at the ADC/DAC sampling point with the highest time resolution of the baseband digital signal processing unit as the timing sampling of the system, compares the timing sampling value with the given 1PPS, feeds back the obtained timing deviation signal to the baseband digital signal processing unit, and realizes the adjustment of the system timing by increasing and decreasing the number of the sampling points in the guard interval GP. The method has the characteristics of high time sampling resolution, concise time timing adjustment and convenient engineering realization, and is suitable for the time timing adjustment of the communication load of the NGSO satellite in the non-stationary orbit.
Example 2:
the embodiment of the present invention provides a clock skew correction device based on a guard interval, which is mainly used for executing the clock skew correction method based on a guard interval provided in the foregoing content of embodiment 1, and the following describes the clock skew correction device based on a guard interval provided in the embodiment of the present invention in detail.
Fig. 5 is a schematic structural diagram of a guard interval-based clock skew correction apparatus according to an embodiment of the present invention. As shown in fig. 5, the apparatus for correcting clock skew based on guard interval mainly includes: an acquisition determining unit 11, a calculating unit 12 and an adjusting unit 13, wherein:
an acquisition determining unit 11, configured to acquire a clock signal of a third party before transmitting or receiving a baseband signal, and determine the clock signal of the third party as a reference signal;
a calculation unit 12 for calculating a clock skew between the target party and the third party based on the reference signal; the target party is a beam hopping satellite communication load or a satellite terminal, the beam hopping satellite communication load and the satellite terminal are respectively provided with a baseband digital signal processing unit, and the baseband digital signal processing unit adopts a target clock to provide a clock signal of the target party at an ADC/DAC sampling point;
an adjusting unit 13, configured to adjust a length of a guard interval of the baseband signal based on the clock offset, so that a difference between a time when the target sends or receives the baseband signal and the reference signal is smaller than a preset time difference; and a guard interval is arranged between every two adjacent signal frames in the baseband signal.
The embodiment of the invention provides a clock deviation correcting device based on a guard interval, which comprises: firstly, before sending or receiving a baseband signal, an obtaining and determining unit 11 is used for obtaining a clock signal of a third party and determining the clock signal of the third party as a reference signal; then, calculating the clock deviation between the target party and the third party by using the calculating unit 12 based on the reference signal; the target party is a beam hopping satellite communication load or a satellite terminal, the beam hopping satellite communication load and the satellite terminal are respectively provided with a baseband digital signal processing unit, and the baseband digital signal processing unit adopts a target clock to provide a clock signal of the target party at an ADC/DAC sampling point; finally, the length of a guard interval of the baseband signal is adjusted by using an adjusting unit 13 based on the clock deviation, so that the difference value between the time for the target party to send or receive the baseband signal and the reference signal is smaller than a preset time difference value; and a guard interval is arranged between every two adjacent signal frames in the baseband signal. The embodiment of the invention corrects the time for the target to send or receive the baseband signal by adjusting the length of the guard interval of the baseband signal, so that the difference value between the time for the target to send or receive the baseband signal and the reference signal is smaller than the preset time difference value, the invention is suitable for the scene that the target cannot directly adjust the clock source, and has the advantages of simple clock deviation correction mode and convenient engineering realization.
Optionally, when the target party is a beam-hopping satellite communication load, the computing unit 12 further includes a first obtaining module and a first computing module, where:
the first acquisition module is used for acquiring a first clock signal; the first clock signal is a clock signal of a hopping beam satellite communication load at an ADC/DAC sampling point;
the first calculation module is used for calculating a first clock deviation between the beam hopping satellite communication load and a third party based on the first clock signal and the reference signal.
Optionally, when the target party is a satellite terminal, the calculating unit 12 further includes: a second obtaining module and a second calculating module, wherein:
the second acquisition module is used for acquiring a second clock signal; the second clock signal is a clock signal of the satellite terminal at an ADC/DAC sampling point;
and the second calculation module is used for calculating a second clock deviation between the satellite terminal and a third party based on the second clock signal and the reference signal.
Optionally, the first computing module is further configured to: comparing the first clock signal with a reference signal to obtain a first comparison result; the first comparison result is determined as a first clock offset between the beam hopping satellite communications payload and a third party.
Optionally, the second calculating module is further configured to: comparing the second clock signal with the reference signal to obtain a second comparison result; the second comparison result is determined as a second clock offset between the satellite terminal and a third party.
Optionally, the adjusting unit is further configured to feed back the clock offset to the target baseband digital signal processing unit, so that the target baseband digital signal processing unit adjusts the length of the guard interval of the baseband signal by increasing or decreasing the number of sampling points in the guard interval of the baseband signal.
Optionally, the reference signal is a 1PPS signal.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In an optional embodiment, the present embodiment further provides an electronic device, which includes a memory and a processor, where the memory stores a computer program operable on the processor, and the processor executes the computer program to implement the steps of the method of the foregoing method embodiment.
In an alternative embodiment, the present embodiment also provides a computer readable medium having non-volatile program code executable by a processor, wherein the program code causes the processor to perform the method of the above method embodiment.
In the description of the present embodiment, it should be noted that the terms "in", "up", "in", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be configured in a specific orientation, and operate, and thus, should not be construed as limiting the present embodiment. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the above two embodiments provided in the present application, it should be understood that the disclosed method and apparatus may be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units is only one logical division, and there may be other divisions when actually implemented, and for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection of devices or units through some communication interfaces, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.
The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a non-volatile computer-readable storage medium executable by a processor. Based on such understanding, the technical solution of the present embodiment or parts of the technical solution may be essentially implemented in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein.

Claims (9)

1. A clock skew correction method based on a guard interval is characterized by comprising the following steps:
before sending or receiving a baseband signal, acquiring a clock signal of a third party, and determining the clock signal of the third party as a reference signal;
calculating a clock offset between the target and the third party based on the reference signal and a clock signal of the target at the ADC/DAC sampling point; the target party is a beam hopping satellite communication load or a satellite terminal, the beam hopping satellite communication load and the satellite terminal are respectively provided with a baseband digital signal processing unit, and the baseband digital signal processing unit adopts a target clock to provide a clock signal of the target party at an ADC/DAC sampling point; the ADC/DAC sampling point is the minimum time unit which can be identified by the baseband signal waveform;
adjusting the length of a guard interval of the baseband signal based on the clock deviation so that the difference between the time of sending or receiving the baseband signal by the target party and the reference signal is smaller than a preset time difference; the guard interval is arranged between every two adjacent signal frames in the baseband signal;
adjusting a length of a guard interval of the baseband signal based on the clock skew, comprising:
feeding the clock deviation back to the baseband digital signal processing unit of the target party so as to enable the baseband digital signal processing unit of the target party to adjust the length of the guard interval of the baseband signal in a mode of increasing or decreasing the number of sampling points in the guard interval of the baseband signal; when the clock signal of the target at the ADC/DAC sampling point is 2.4GSPS, the time interval of the sampling points is 0.4167nS, one sampling point is increased or decreased, the time adjustment amount is 0.4167nS, the deviation between the reference signal and the clock signal of the target at the ADC/DAC sampling point is controlled to be 10 at minimum-3PPM。
2. The method of claim 1, wherein calculating a clock bias between the target and the third party based on the reference signal when the target is a beam-hopping satellite communications payload comprises:
acquiring a first clock signal; wherein the first clock signal is a clock signal of the beam hopping satellite communication load at an ADC/DAC sampling point;
calculating a first clock offset between the beam hopping satellite communications payload and the third party based on the first clock signal and the reference signal.
3. The method of claim 1, wherein calculating the clock bias between the target and the third party based on the reference signal when the target is a satellite terminal comprises:
acquiring a second clock signal; the second clock signal is a clock signal of the satellite terminal at an ADC/DAC sampling point;
calculating a second clock offset between the satellite terminal and the third party based on the second clock signal and the reference signal.
4. The method of claim 2, wherein calculating a first clock bias between the beam hopping satellite communications payload and the third party based on the first clock signal and the reference signal comprises:
comparing the first clock signal with the reference signal to obtain a first comparison result;
determining the first comparison result as a first clock offset between the beam hopping satellite communications payload and the third party.
5. The method of claim 3, wherein calculating a second clock bias between the satellite terminal and the third party based on the second clock signal and the reference signal comprises:
comparing the second clock signal with the reference signal to obtain a second comparison result;
determining the second comparison result as a second clock offset between the satellite terminal and the third party.
6. The method of claim 1, wherein the reference signal is a 1PPS signal.
7. A guard interval-based clock skew correction apparatus, comprising:
the device comprises an acquisition determining unit, a processing unit and a processing unit, wherein the acquisition determining unit is used for acquiring a clock signal of a third party before transmitting or receiving a baseband signal and determining the clock signal of the third party as a reference signal;
a calculating unit, for calculating the clock deviation between the target party and the third party based on the reference signal and the clock signal of the target party at the sampling point of the ADC/DAC; the target party is a beam hopping satellite communication load or a satellite terminal, the beam hopping satellite communication load and the satellite terminal are respectively provided with a baseband digital signal processing unit, and the baseband digital signal processing unit adopts a target clock to provide a clock signal of the target party at an ADC/DAC sampling point; the ADC/DAC sampling point is the minimum time unit which can be identified by the baseband signal waveform;
an adjusting unit, configured to adjust a length of a guard interval of the baseband signal based on the clock offset, so that a difference between a time when the target sends or receives the baseband signal and the reference signal is smaller than a preset time difference; the guard interval is arranged between every two adjacent signal frames in the baseband signal;
the adjusting unit is further used for feeding back the clock deviation to the baseband digital signal processing unit of the target party so as to enable the baseband digital signal processing unit of the target party to adjust the length of the guard interval of the baseband signal in a mode of increasing or decreasing the number of sampling points in the guard interval of the baseband signal; when the clock signal of the target at the ADC/DAC sampling point is 2.4GSPS, the time interval of the sampling points is 0.4167nS, one sampling point is increased or decreased, the time adjustment amount is 0.4167nS, the deviation between the reference signal and the clock signal of the target at the ADC/DAC sampling point is controlled to be 10 at minimum-3PPM。
8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method according to any one of claims 1 to 6 when executing the computer program.
9. A computer-readable medium having non-volatile program code executable by a processor, the program code causing the processor to perform the method of any of claims 1 to 6.
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