A Multi-Node Local Oscillator Signal Phase Synchronization Method and System

Abstract

The present invention belongs to the technical field of phase synchronization. In order to solve the problems of error accumulation and dependence on external reference signals existing in the phase synchronization of local oscillator signals of existing multi-node systems, a method and system for phase synchronization of local oscillator signals of multi-node systems are proposed. The master node calculates the phase delay compensation value between the master node and the slave node through signal frequency doubling loopback and real-time phase discrimination; the slave node compensates the phase of the received local oscillator signal based on the phase delay compensation value, and outputs the phase-compensated local oscillator signal as the local oscillator signal of the slave node, realizing the phase synchronization of the local oscillator signals between the master and slave nodes. The present invention is that the homologous signals perform phase synchronization with themselves at different nodes, and the directions and magnitudes of the frequency drift of the local oscillator signals at each node are the same, thus avoiding the problem of frequency synchronization in the existing methods and directly focusing on solving the problem of signal phase synchronization.

Description

Technical Field

[0001] The present invention belongs to the technical field related to phase synchronization, and in particular, relates to a method and system for phase synchronization of local oscillator signals of multiple nodes. Background Art

[0002] The statements in this part only provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] Multi-node signal synchronization is of great significance for distributed radars and distributed communications. Currently, the research on multi-node synchronization mainly focuses on time-frequency synchronization, while there are few research results on signal phase synchronization, especially local oscillator signal synchronization. For fully coherent distributed radars, it is required that the transmitted signals and received signals of multiple nodes both satisfy high coherence. The local oscillator signal is the metronome of the entire radar system, providing a basic frequency reference for the transmitting and receiving channels. The phase synchronization performance of local oscillator signals of multiple nodes separated in space is decisive for the detection performance of distributed radars.

[0004] In the prior art, Patent CN117792599A proposes a dual-system phase synchronization method, device, electronic device, medium, and program product. The dual-system uses independent local oscillators, and the two time-frequency phase systems detect signal frequency and clock errors and calibrate signal parameters by exchanging timestamps, and finally achieve dual-system signal phase synchronization. This method requires frequency calibration, clock calibration, and then phase synchronization between the dual-systems successively, with a relatively complex process and error accumulation in the implementation process, making it difficult to obtain high phase synchronization accuracy. Patent CN112134678A proposes a dual-node phase synchronization method, which uses radar carrier synchronization pulses to transmit bidirectionally to obtain the frequency difference and phase noise signals between the two nodes, and uses them to compensate the received echo and achieve received phase synchronization. This method realizes echo phase synchronization and is ineffective for fully coherent transmit synchronization.

[0005] The difficulties in multi-node local oscillator signal phase synchronization are concentrated in the inconsistency of frequency drift between different frequency sources. Currently, there are mainly two ways to solve this problem:

[0006] One is to use an external highly stable frequency source as a reference, such as a GPS timing signal. Each node uses a phase-locked loop to achieve signal frequency taming, and on this basis, phase synchronization is achieved by exchanging synchronization signals. Such methods rely heavily on external reference signals and are not applicable to many ground or spaceborne distributed radars;

[0007] The other is to directly exchange timestamped synchronization signals between the master and slave nodes to achieve phase synchronization on the basis of frequency synchronization and clock synchronization, with a relatively complex process and inevitable error accumulation. Summary of the Invention

[0008] To overcome the deficiencies of the above-mentioned prior art, the present invention provides a multi-node local oscillator signal phase synchronization method and system. The homologous signals are phase-synchronized with themselves at different nodes, and the directions and magnitudes of the frequency drifts of the local oscillator signals at each node are the same, thereby avoiding the frequency synchronization problem in the existing methods and achieving high-precision phase synchronization among multiple nodes.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a multi-node local oscillator signal phase synchronization method. The multi-node includes a master node and at least one slave node. The method includes:

[0011] The master node distributes the generated local oscillator signal to at least one slave node;

[0012] The master node calculates the phase delay compensation value between the master node and the slave node through signal frequency doubling loopback and real-time phase discrimination;

[0013] The slave node performs phase compensation on the received local oscillator signal based on the phase delay compensation value, and outputs the phase-compensated local oscillator signal as the local oscillator signal of the slave node, thereby realizing the phase synchronization of the local oscillator signals between the master and slave nodes.

[0014] In a second aspect, the present invention provides a multi-node local oscillator signal phase synchronization system, including a master node and at least one slave node, wherein:

[0015] The master node is configured to distribute the generated local oscillator signal to at least one slave node; calculate the phase delay compensation value between the master node and the slave node through signal frequency doubling loopback and real-time phase discrimination;

[0016] The slave node is configured to perform phase compensation on the received local oscillator signal based on the phase delay compensation value, and output the phase-compensated local oscillator signal as its own local oscillator signal, thereby realizing the phase synchronization of the local oscillator signals between the master and slave nodes.

[0017] The above one or more technical solutions have the following beneficial effects:

[0018] The present invention adopts a mode in which the master node distributes the local oscillator signal externally. The slave node does not use an independent crystal oscillator, but uses the local oscillator signal received from the master node as its own local oscillator signal output after phase compensation. The master node calculates the phase delay compensation value between the master and slave nodes through signal frequency doubling loopback and real-time phase discrimination. The slave node performs phase compensation on the received local oscillator signal based on the phase delay compensation value, thereby realizing the phase synchronization of the local oscillator signals of the master and slave nodes. In the present invention, the homologous signals are phase-synchronized with themselves at different nodes, and the direction and magnitude of the frequency drift of the local oscillator signals at each node are the same, thus avoiding the problem of frequency synchronization in the existing methods and directly focusing on solving the problem of signal phase synchronization.

[0019] The master node of the present invention can be paired with multiple slave nodes. The multiple slave nodes can simultaneously receive the local oscillator signal distributed by the master node and perform phase synchronization with the master node respectively, thereby forming the phase synchronization of the local oscillator signals of multiple nodes, which has better scalability than the existing methods.

[0020] Advantages of additional aspects of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The specification drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0022] Figure 1 It is a structural block diagram of the local oscillator signal distribution and phase synchronization device in an embodiment of the present invention;

[0023] Figure 2 It is the corresponding relationship diagram between the output phase of the first phase discriminator and in an embodiment of the present invention;

[0024] Figure 3 It is the corresponding relationship diagram between the output phase of the second phase discriminator and in an embodiment of the present invention;

[0025] Figure 4 It is the corresponding relationship diagram between the difference between the outputs of the first phase discriminator and the second phase discriminator and in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0027] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention.

[0028] In the case of no conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0029] This embodiment discloses a multi-node local oscillator signal phase synchronization system, including a master node and at least one slave node, where:

[0030] The master node is configured to distribute the generated local oscillator signal to at least one slave node; calculate the phase delay compensation value between the master node and the slave node through signal frequency doubling loopback and real-time phase discrimination.

[0031] The slave node is configured to perform phase compensation on the received local oscillator signal based on the phase delay compensation value, and output the phase-compensated local oscillator signal as its own local oscillator signal, so as to realize the phase synchronization of the local oscillator signals between the master and slave nodes.

[0032] This embodiment adopts a mode in which the master node distributes the local oscillator signal externally. The slave node does not use an independent crystal oscillator, but takes the local oscillator signal received from the master node as its own local oscillator output after phase compensation. The master node obtains the transceiver channel delay phase between the master and slave nodes through signal frequency doubling loopback and real-time phase discrimination, and calculates the phase delay compensation value; the slave node obtains the phase delay compensation value through the communication channel, and performs phase compensation on the received local oscillator signal, and outputs the compensated local oscillator signal as its own local oscillator signal, thereby realizing the phase synchronization of the local oscillator signals between the master and slave nodes.

[0033] This embodiment does not require an external frequency source to provide a reference signal. The master node adopts a crystal oscillator circuit with a highly stable frequency. The signal frequency drift during the distribution, reception, and loopback of the local oscillator signal can be ignored. The signal phase difference between the master and slave nodes is only related to the signal propagation channel delay.

[0034] The master node can be paired with multiple slave nodes. The multiple slave nodes can simultaneously receive the local oscillator signal distributed by the master node, and perform phase synchronization with the master node respectively, so as to form the phase synchronization of the local oscillator signals of multiple nodes. The following combines Figure 1 Taking the local oscillator signal phase synchronization system including a master node and a slave node as an example for detailed description:

[0035] The master node includes: a crystal oscillator module, a transmitter power divider, a first receiver power divider, an amplified transmitter circuit and an antenna, an amplified receiver circuit and an antenna, a doubler, a tripler, a first phase discriminator, i.e., phase discriminator A, a second phase discriminator, i.e., phase discriminator B, a 2x frequency band-pass filter, a 3x frequency band-pass filter, a first calculation and control unit, a data communication unit and an antenna.

[0036] Among them, the crystal oscillator module is used to generate the local oscillator signal;

[0037] The transmitting end power splitter is used to divide the local oscillator signal into a distribution signal and a phase discrimination reference signal;

[0038] The first receiving end power splitter is used to divide the received signal into two signals, which are respectively used as the inputs of the 2 - times - frequency band - pass filter and the 3 - times - frequency band - pass filter;

[0039] The 2 - times - frequency band - pass filter is used to separate the 2 - times - frequency signal in the loopback channel;

[0040] The 3 - times - frequency band - pass filter is used to separate the 3 - times - frequency signal in the loopback channel;

[0041] The first phase discriminator and the second phase discriminator are respectively used to perform phase detection on signals of different frequency multiples;

[0042] The first calculation and control unit is used to calculate the phase delay compensation value according to the phase discrimination results of the first phase discriminator and the second phase discriminator.

[0043] The slave node includes: the second receiving end power splitter, the transmitting end combiner, the amplified transmitting circuit and antenna, the amplified receiving circuit and antenna, the 2 - times - frequency multiplier, the 3 - times - frequency multiplier, the digital phase shifter, the calculation and control unit, and the data communication unit and antenna.

[0044] Among them, the second receiving end power splitter is used to distribute the received local oscillator signal into a first signal, a second signal, and a third signal;

[0045] The 2 - times - frequency multiplier is used to perform 2 - times - frequency processing on the second signal;

[0046] The 3 - times - frequency multiplier is used to perform 3 - times - frequency processing on the third signal;

[0047] The second calculation and control unit is used to generate a phase shift instruction according to the phase delay compensation value and send it to the digital phase shifter;

[0048] The digital phase shifter is used to perform phase compensation on the first signal.

[0049] This embodiment requires that the signal frequency output by the crystal oscillator module of the master node has high stability, and the frequency drift within the signal loopback period can be ignored; the transceiver circuits in the local oscillator signal transmitting channel and the loopback channel have good consistency, and the signal phase delays of all components can be measured and are stable.

[0050] In this embodiment, the master node distributes the local oscillator signal to the slave node through the wireless channel. After receiving the local oscillator signal, the slave node divides it into a first path signal, a second path signal, and a third path signal. Among them, the first path signal is output as the local oscillator signal of the slave node after phase compensation. In addition, the second path signal and the third path signal are frequency-multiplied differently and then sent back to the master node through the loopback channel for phase discrimination. The master node uses the difference between the outputs of the two phase discriminators to solve the signal phase delay between the master and slave nodes, and sends the phase delay compensation value to the slave node. Finally, the local oscillator signal of the slave node achieves high-precision phase synchronization with the local oscillator signal of the master node through active phase compensation.

[0051] The specific implementation process of the local oscillator signal phase synchronization system is as follows:

[0052] The local oscillator signal of the master node is divided into 4 paths, which are respectively used for: 1. As the local oscillator signal of the master node; 2. Distributing signals to the slave node; 3. Doubling the frequency as the reference signal of the first phase discriminator; 4. Tripling the frequency as the reference signal of the second phase discriminator.

[0053] Among them, the initial phases of the 4 path signals output by the transmitter power divider are the same, denoted as .

[0054] The slave node receives the local oscillator signal distributed by the master node. After passing through the amplified receiving circuit, it is divided into 3 paths by the second receiving end power divider. Among them, the first path signal enters the digital phase shifter and is output as the local oscillator signal of the slave node after phase compensation; the second path signal is frequency-doubled and then sent into the loopback channel; the third path signal is frequency-tripled and then sent into the loopback channel.

[0055] Among them, the initial phases of the 3 path outputs of the second receiving end power divider are the same, denoted as .

[0056] Let the channel phase delay from the transmission of the local oscillator signal by the master node to the reception by the slave node be:

[0057]

[0058] Among them, K is a positive integer, represents the phase residue where the channel delay is less than one cycle, and it is also the key to the phase compensation of the local oscillator signal of the slave node.

[0059] On the slave node side, the phase of the signal output by the second receiving end power divider is:

[0060]

[0061] Among them, represents the phase delay caused by the power divider, which is usually linearly related to the operating frequency. For a known frequency it is stable and measurable. After phase shift compensation Can be ignored.

[0062] It should be noted that the phase delays caused by the transmitter power splitter, the first receiver power splitter, and the second receiver power splitter described in this embodiment are the same. Therefore, they are uniformly represented by to represent the phase delay of the power splitter.

[0063] The slave node multiplies the second and third signals output from the second receiver power splitter by 2 and 3 times respectively. After passing through the transmitter combiner, they are sent back to the master node through the wireless channel to form a signal loop.

[0064] The master node separates the received loop signal through a 2 - frequency - band - pass filter. The 2 - frequency signal is connected to the first phase detector and phase - detected with its reference signal.

[0065] The phase of the reference signal of the first phase detector Can be expressed as:

[0066]

[0067] Wherein, represents the phase delay caused by the 2 - multiplier.

[0068] The phase of the loop signal connected to the first phase detector Is expressed as:

[0069]

[0070] Wherein, represents the local - oscillator phase delay caused by the combiner, represents the local - oscillator phase delay caused by the power splitter, represents the phase delay caused by the 2 - frequency - band - pass filter.

[0071] Then the output of the first phase detector should be expressed as:

[0072]

[0073]

[0074] Wherein, represents the phase delay caused by the power splitter, combiner, and 2 - frequency - band - pass filter on the 2 - frequency loop branch. The above values can be measured in advance. After fixed - phase compensation, Can be ignored. K is a positive integer.

[0075] Therefore, the output of the first phase detector can be expressed as:

[0076]

[0077] Since , There is an ambiguous correspondence with and the relationship image is as shown in Figure 2 .

[0078] Similarly, the third harmonic loop signal is connected to the second phase detector, and its phase is expressed as :

[0079]

[0080] where represents the phase delay caused by the third harmonic generator, represents the phase delay of the third harmonic band-pass filter.

[0081] The reference signal of the second phase detector is expressed as:

[0082]

[0083] The output of the second phase detector is:

[0084]

[0085] where

[0086]

[0087] Similar to the conclusion of the first phase detector, the output of the second phase detector can be expressed as:

[0088]

[0089] where represents the phase delay caused by the power divider, combiner and third harmonic band-pass filter on the third harmonic loop path.

[0090] Since , There is an ambiguous correspondence with and the relationship image is as shown in Figure 3 .

[0091] The outputs of the first phase detector and the second phase detector are sent to the first calculation and control unit of the main node, and the parameter is calculated. The calculation result is as shown in Figure 4 , There is a non-ambiguous correspondence with .

[0092] The main node sends the calculation result to the slave node through the data communication unit. The second calculation and control unit of the slave node generates a phase shift instruction according to this data and sends it to the digital phase shifter.

[0093] The digital phase shifter compensates the phase of the output of the second receiving end power divider of the slave node, and the phase of the output signal is:

[0094]

[0095] At this time, the local oscillator signals output by the slave node and the master node are of the same frequency and in phase.

[0096] This embodiment discloses a method for phase synchronization of local oscillator signals of multiple nodes. The multiple nodes include a master node and at least one slave node, and the method includes:

[0097] The master node distributes the generated local oscillator signal to at least one slave node;

[0098] The master node calculates the phase delay compensation value between the master node and the slave node through signal frequency doubling loopback and real-time phase discrimination;

[0099] The slave node performs phase compensation on the received local oscillator signal based on the phase delay compensation value, and outputs the phase-compensated local oscillator signal as the local oscillator signal of the slave node, so as to realize the phase synchronization of the local oscillator signals between the master and slave nodes.

[0100] As an implementation manner, the master node calculates the phase delay compensation value between the master node and the slave node through signal frequency doubling loopback and real-time phase discrimination, specifically:

[0101] After receiving the local oscillator signal of the master node, the slave node divides the local oscillator signal into a first path signal, a second path signal, and a third path signal; the second path signal and the third path signal are sent back to the master node through the loopback channel after different frequency doublings, and the master node uses two phase discriminators to detect the phase difference and calculate the phase delay compensation value between the master node and the slave node.

[0102] Specifically, the second path signal and the third path signal are respectively processed by frequency doubling by 2 times and 3 times, and then sent back to the master node through the loopback channel;

[0103] The master node respectively performs phase difference detection on the 2-fold frequency signal and the 3-fold frequency signal received by the first phase discriminator and the second phase discriminator, and obtains a first phase discrimination result and a second phase discrimination result;

[0104] The master node calculates the phase delay compensation value between the master node and the slave node according to the difference between the first phase discrimination result and the second phase discrimination result.

[0105] This embodiment uses the phase discrimination results of two loopback signals with phase ambiguity to obtain an unambiguous phase estimation of the local oscillator signal. That is, the phase discrimination results of the 2-fold frequency and 3-fold frequency loopback signals are individually phase ambiguous, but the difference between the two has a one-to-one correspondence with the signal phase delay between the master and slave nodes, so as to calculate and obtain an accurate phase compensation.

[0106] In this embodiment, only the master node has an independent oscillator for generating the local oscillator signal, and the slave nodes do not have independent signal sources. Therefore, the entire system is a homologous signal that synchronizes its phase with itself at different nodes. The direction and magnitude of the frequency drift of the local oscillator signal are the same at each node, thus avoiding the frequency synchronization problem in the existing methods and allowing direct focus on solving the signal phase synchronization problem.

[0107] Although the specific implementation manners of the present invention have been described above in conjunction with the accompanying drawings, they do not limit the protection scope of the present invention. Those skilled in the art should understand that, based on the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts still fall within the protection scope of the present invention.

Claims

1. A multi-node local oscillator signal phase synchronization method, characterized in that The multi-node includes a master node and at least one slave node, and the method includes: The master node distributes the generated local oscillator signal to at least one slave node; The master node calculates the phase delay compensation value between the master node and the slave node through signal frequency doubling loopback and real-time phase discrimination, specifically: After receiving the local oscillator signal of the master node, the slave node divides the local oscillator signal into a first path signal, a second path signal, and a third path signal; the second path signal and the third path signal are sent back to the master node through the loopback channel after different frequency doublings, and the master node uses two phase discriminators to detect the phase difference and calculate the phase delay compensation value between the master node and the slave node; The slave node performs phase compensation on the received local oscillator signal based on the phase delay compensation value, and outputs the phase-compensated local oscillator signal as the local oscillator signal of the slave node, realizing the phase synchronization of the local oscillator signals between the master and slave nodes.

2. The multi-node local oscillator signal phase synchronization method according to claim 1, characterized in that The second path signal and the third path signal are sent back to the master node through the loopback channel after different frequency doublings, and the master node uses two phase discriminators to detect the phase difference and calculate the phase delay compensation value between the master node and the slave node, specifically: The second path signal and the third path signal are respectively processed by frequency doubling by 2 times and 3 times, and then sent back to the master node through the loopback channel; The master node respectively uses the first phase discriminator and the second phase discriminator to detect the phase difference of the received frequency-doubled-by-2 signal and the frequency-doubled-by-3 signal, and obtains a first phase discrimination result and a second phase discrimination result; The master node calculates the phase delay compensation value between the master node and the slave node according to the difference between the first phase discrimination result and the second phase discrimination result.

3. A multi-node local oscillator signal phase synchronization method according to claim 1, characterized in that, The slave node adjusts the phase compensation amount of the digital phase shifter for the first path signal according to the phase delay compensation value.

4. A multi-node local oscillator signal phase synchronization method according to claim 1, characterized in that The initial phases of the first path signal, the second path signal, and the third path signal are the same.

5. The multi-node local oscillator signal phase synchronization method according to claim 1, wherein The master node simultaneously performs phase synchronization with multiple slave nodes, and each slave node independently performs phase compensation to realize the phase synchronization of the local oscillator signals of multiple nodes.

6. A multi-node local oscillator signal phase synchronization system, characterized in that, Including a master node and at least one slave node, where: The master node is used to distribute the generated local oscillator signal to at least one slave node; calculate the phase delay compensation value between the master node and the slave node through signal frequency doubling loopback and real-time phase discrimination, specifically: After receiving the local oscillator signal of the master node, the slave node divides the local oscillator signal into a first path signal, a second path signal, and a third path signal; the second path signal and the third path signal are sent back to the master node through the loopback channel after different frequency doublings, and the master node uses two phase discriminators to detect the phase difference and calculate the phase delay compensation value between the master node and the slave node; The slave node is used to perform phase compensation on the received local oscillator signal based on the phase delay compensation value, and output the phase-compensated local oscillator signal as its own local oscillator signal, realizing the phase synchronization of the local oscillator signals between the master and slave nodes.

7. The multi-node local oscillator signal phase synchronization system according to claim 6, characterized in that, The master node includes a crystal oscillator module, a transmitting end power divider, a first receiving end power divider, a first phase discriminator, a second phase discriminator, and a first calculation and control unit; where: The crystal oscillator module is used to generate a local oscillator signal; The transmitting end power splitter is used to divide the local oscillator signal into multiple distributed signals; The first receiving end power splitter is used to divide the received signal into two signals, which are respectively used as the inputs of different frequency - multiplied band - pass filters; The first phase discriminator and the second phase discriminator are respectively used to detect the phases of signals with different frequency multiplications; The first calculation and control unit is used to calculate the phase delay compensation value according to the phase discrimination results of the first phase discriminator and the second phase discriminator.

8. A multi-node local oscillator signal phase synchronization system according to claim 6, characterized in that The slave node includes a second receiving end power splitter, a digital phase shifter, a frequency multiplier, and a second calculation and control unit; where: The second receiving end power splitter is used to distribute the received local oscillator signal into a first signal, a second signal, and a third signal; The frequency multiplier is used to perform different frequency - multiplication processing on the second signal and the third signal; The second calculation and control unit is used to generate a phase - shifting instruction according to the phase delay compensation value and send it to the digital phase shifter; The digital phase shifter is used to perform phase compensation on the first signal.

9. A multi-node local oscillator signal phase synchronization system according to claim 6 or 7, characterized in that, The different frequency - multiplied band - pass filters are used to separate the corresponding frequency - multiplied signals in the loopback signal.

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