A link time service method, device, system and medium for wireless synchronization and grid connection

Abstract

A wireless synchronization and grid-connected link time service method, device, system and medium, first, the adaptive Kalman filtering algorithm is used for online smoothing processing of time service information, realizing adaptive suppression of random delay jitter; second, the augmented state model is constructed, the link asymmetric delay is introduced into the filter as the state variable, realizing the joint estimation and compensation of clock offset and asymmetric delay; third, a lightweight encryption and LDPC / STBC combined coding robust transmission mechanism is designed, and combined with the adaptive channel selection strategy, the reliable transmission of time service signal in the interference and congestion environment is ensured; finally, a hierarchical fusion of multi-source time service information and local high-precision clock verification method is proposed, which improves the continuity and reliability of the system. The present application can realize the consistency of high-precision time reference of multiple distributed detection terminals in the wireless public network environment, and significantly improve the precision and stability of the smart grid and differential measurement.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication and time synchronization technology, and specifically relates to a link timing method for achieving high-precision synchronous grid connection through wireless communication links such as 4G / 5G in scenarios such as smart grids and industrial automation. It is a link timing method, device, system and medium for wireless synchronous grid connection. Background Technology

[0002] In applications such as synchronous grid connection and line status monitoring in smart grids, it is often necessary to collect synchronous voltage and current signals at two or more physically separated points, such as the main grid side and the load side of a ring main unit, and calculate key parameters such as phase difference by comparing the timestamps of the collected data. This application mode places extremely high demands on the consistency of time bases among multiple acquisition terminals.

[0003] Traditional solutions typically rely on GPS modules or wired networks (such as fiber optics) to achieve time synchronization among terminals. However, in many substations, underground power distribution rooms, or mobile emergency scenarios, GPS signals may not provide reliable coverage, while laying wired networks is costly and inflexible. Therefore, utilizing widely covered public wireless networks such as 4G / 5G to construct a wireless differential measurement system consisting of a host terminal and multiple detection terminals has become a highly attractive technological direction.

[0004] In the aforementioned wireless differential measurement system, the host terminal typically acts as the local time master, broadcasting or requesting time synchronization information from each probe terminal via a wireless link. The goal is to ensure that the time base of all probe terminals is strictly aligned with that of the host terminal, thereby achieving relative synchronization among the probe terminals. However, applying high-precision time synchronization protocols such as PTP to this system architecture based on a public wireless network presents significant challenges:

[0005] First, there is time-varying path delay jitter in the communication. Factors such as wireless channel quality and base station load can introduce random and dynamically changing transmission delays, causing the arrival time of the communication messages between the host and each probe to be extremely unstable, resulting in millisecond-level jitter, which seriously undermines the consistency and stability of the time reference of each probe.

[0006] Secondly, asymmetric path delays exist in the actual time synchronization process. Differences in resource allocation and physical paths between the uplink and downlink of 4G / 5G networks often result in unequal transmission delays for the synchronized time messages in both the host-to-detector and detector-to-host directions—asymmetric delays. This leads to a systematic time synchronization error between the host and each detector, and because each detector has a different wireless path, this error value may also vary, ultimately preventing true time alignment between the detectors.

[0007] Secondly, wireless links are susceptible to interference and bit errors. Wireless channels are vulnerable to electromagnetic interference, multipath effects, or network congestion, which can lead to the loss or distortion of data packets in the timing signal, resulting in decreased timing accuracy or even synchronization interruption.

[0008] Furthermore, relying on a single time synchronization source presents reliability issues. Whether relying solely on the PTP wireless link or on GNSS, there is a risk of single point of failure. For example, GNSS signals may be interrupted due to building obstruction, and the wireless network may become unavailable due to base station failure or congestion. Neither of these can meet the high requirements for time synchronization continuity in grid-connected operations.

[0009] Existing technologies for addressing timing accuracy issues mostly focus on filtering methods to solve path delay jitter, without considering other related problems.

[0010] In summary, despite the need for time synchronization using public wireless networks, existing technologies, whether directly applying traditional protocols like PTP or relying on a single GNSS signal, cannot systematically address the four core challenges simultaneously present in wireless links: time-varying jitter, asymmetric delay, channel interference, and single points of failure. These problems are interdependent and work together, resulting in poor performance of existing methods in practical applications. Therefore, there is an urgent need in this field for a comprehensive time synchronization method specifically designed for complex wireless environments, capable of providing high accuracy, high stability, and high reliability. Summary of the Invention

[0011] The problem this invention aims to solve is that existing technologies cannot simultaneously address the issues of time-varying jitter, asymmetric delay, channel interference, and single point of failure that exist in wireless links. The purpose of this invention is to overcome the shortcomings of existing technologies and provide a high-precision, high-reliability link timing method for wireless synchronization and networking.

[0012] The technical solution of this invention is: a link timing method for wireless synchronization and networking, applied to a wireless communication system including a host terminal and at least two probe terminals, comprising the following steps:

[0013] Step 1: Measure the time offset of the timing information exchanged between the host and the probe, and perform time-varying delay adaptive compensation. The compensation adopts an adaptive filtering algorithm, which dynamically adjusts the filtering parameters according to the real-time measured time offset error to suppress the path delay jitter of the wireless link.

[0014] Step 2: Construct an augmented state model that includes clock state and link asymmetric delay. Introduce the link asymmetric delay as a state variable and add it together with time offset and clock drift into the adaptive filtering algorithm for joint estimation, so as to achieve joint estimation and compensation of time offset and asymmetric delay.

[0015] Step 3: The timing signal is encrypted and encoded before transmission to ensure reliability. During transmission, an adaptive channel selection strategy is adopted, which adaptively hops frequency or switches to a preset backup communication channel according to the channel quality to cope with wireless link interference or network congestion.

[0016] Step 4: Merge time information from different time sources and verify the fusion result using a local high-precision clock.

[0017] The present invention also provides a link timing device for wireless synchronization and networking, comprising:

[0018] A time-varying delay compensation module is used to dynamically adjust the filtering parameters according to the real-time measurement error using an adaptive filtering algorithm to filter the timing information in order to suppress path delay jitter in the wireless link.

[0019] An asymmetric delay compensation module, coupled to the time-varying delay compensation module, is used to introduce the link asymmetric delay as a state variable by constructing an augmented state model based on the adaptive filtering algorithm, thereby realizing the joint estimation and compensation of clock offset and asymmetric delay.

[0020] A robust transmission module is used to perform security hardening and reliability assurance processing on the time synchronization signal, and to execute an adaptive channel selection strategy to ensure the transmission quality of the time synchronization signal;

[0021] A multi-source fusion verification module is used to fuse time information from different time sources and verify the fusion result using a local high-precision clock to improve the continuity and reliability of the time service.

[0022] The present invention also provides a wireless synchronous network system, comprising:

[0023] At least one host side;

[0024] At least one probe, which communicates with the host via a wireless link; and

[0025] The high-precision link timing device described above is deployed on the host end and / or the probe end to achieve time base synchronization between the probe end and the host end.

[0026] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-described link timing method.

[0027] This invention is applicable to differential measurement systems with a host-detector architecture. It can effectively suppress time-varying jitter and asymmetric delay in the wireless link, and ensure reliable transmission and continuity of timing information in complex electromagnetic environments, ultimately achieving a high degree of consistency of time references among multiple detectors. Compared with existing technologies, the advantages of this invention are:

[0028] 1. Architecture Matching and Precise Synchronization. This invention perfectly matches the "host-detector" architecture of a wireless differential measurement system. By synchronizing all detectors to a single local master clock (host), it ensures a high degree of consistency in the time reference among the detectors, providing a reliable prerequisite for accurate phase difference calculation.

[0029] 2. High robustness and high reliability. By employing an anti-interference robust transmission mechanism and a multi-source timing information fusion verification method, the bottlenecks of wireless timing being susceptible to interference and single points of failure are resolved, greatly improving the system's survivability in harsh industrial environments and the continuity of timing services.

[0030] 3. Strong time-varying jitter suppression capability. Employing an adaptive Kalman filter, it can track the statistical characteristics of wireless link changes in real time, exhibiting strong suppression capability and robustness against time-varying and severe latency jitter in 4G / 5G networks.

[0031] 4. Root cause elimination of system errors is achieved. Unlike existing technologies that avoid or ignore asymmetric delay issues, this invention incorporates asymmetric delay, a source of system error, into the filter's state estimation framework through an augmented state model. This achieves optimal estimation and compensation for synchronization with the clock state, fundamentally eliminating the impact of wireless link asymmetry on synchronization accuracy. This is the key to achieving high accuracy. Attached Figure Description

[0032] To provide a clearer and more complete description of the technical solution of the present invention, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the drawings are merely illustrative and not strictly drawn to scale. Without affecting the understanding of the technical solution of the present invention, certain structures or details well-known in the art may be omitted in the drawings. Similarly, the combination relationships of the components shown in the drawings are merely examples, and the scope of protection of the present invention is not limited to the specific structures and connections shown in the drawings. In the description of this specification, the same reference numerals refer to the same or similar components. Specific descriptions of the drawings are as follows:

[0033] Figure 1 This is a schematic diagram of the system architecture of the present invention.

[0034] Figure 2 This is a schematic diagram of the high-precision link timing method of the present invention.

[0035] Figure 3 This is a schematic diagram of the augmented state model of the present invention.

[0036] Figure 4 This is a diagram of the multi-source time synchronization information fusion and verification architecture of the present invention. Detailed Implementation

[0037] In wireless environments, time-varying jitter, asymmetric delay, channel interference, and single-source reliability problems coexist and are interdependent; no single technology or simple combination can achieve ideal results. Therefore, this invention proposes a comprehensive four-in-one solution, where each component works synergistically to achieve high-precision synchronization and network link time synchronization in wireless communication links.

[0038] This invention is applied to synchronous networking in wireless communication systems, including a host terminal and at least one probe terminal, and achieves high-precision synchronous networking link timing through the following four solutions.

[0039] 1. An Online Adaptive Filtering Compensation Method for Time-Varying Jitter in Wireless Links. Addressing the millisecond-level random delay jitter problem in 4G / 5G wireless links, this invention proposes an adaptive Kalman filter (AKF) algorithm to smooth the timestamp information exchanged via Precision Time Protocol (PTP) online. This method establishes a dynamic state-space model of the clock and treats the error introduced by link jitter during measurement as time-varying measurement noise. By calculating the filtering innovation sequence (i.e., measurement residual) in real time, the measurement noise covariance matrix is ​​dynamically adjusted, enabling the filter to adapt to changes in jitter intensity. When jitter intensifies, the confidence in current measurements containing significant noise is automatically reduced, relying more on model predictions, thereby effectively suppressing the impact of jitter on clock state estimation and significantly improving the stability of the time reference.

[0040] 2. A Link Asymmetric Delay Estimation and Compensation Method Based on Augmented State Model. To address the fundamental problem of systematic timing errors introduced by the traditional PTP protocol due to the disruption of its core symmetry assumption by the wireless link, this invention abandons this unrealistic assumption and innovatively constructs an augmented state model. This method treats "asymmetric delay" as an independent state variable, incorporating it along with clock skew and clock drift into the state vector of a Kalman filter for joint estimation. By modifying the measurement equation accordingly, the filter can simultaneously output optimal estimates of both clock skew and asymmetric delay components in each iteration. This method does not rely on the prerequisite of symmetric link delay, fundamentally eliminating the systematic errors introduced by asymmetric delay and achieving accurate compensation for clock skew.

[0041] 3. Robust Transmission Mechanism for Interference-Resistant Timing Signals. Considering the susceptibility of wireless channels to electromagnetic interference and network congestion, which can lead to timing signal loss or distortion, this invention designs a robust transmission mechanism to resist interference. This mechanism comprises two layers: First, at the physical and data link layers, a combined strategy of "lightweight encryption + robust channel coding" is employed for critical timing messages. The robust coding preferably combines low-density parity-check codes (LDPC) with strong error correction capabilities with space-time block codes (STBC) with excellent anti-fading performance to ensure data transmission integrity. Second, at the network layer, an adaptive channel selection strategy is implemented. By monitoring channel quality in real time, when the link deteriorates, such as when the bit error rate exceeds 10⁻⁻⁶, the mechanism will detect and address any issues. 5 If the interference intensity exceeds 90dB, it will automatically trigger adaptive frequency hopping or switch to a preset backup communication channel to actively avoid interference sources and ensure the continuity of the timing link.

[0042] 4. A Hierarchical Fusion and Verification Method for Multi-Source Time Information. To address the issue of insufficient system reliability caused by the potential interruption of a single time source (such as GPS or single-link PTP) due to signal obstruction or interference, this invention proposes a hierarchical fusion and verification architecture for multi-source time information. This architecture can access and integrate various heterogeneous time sources, including but not limited to Global Navigation Satellite Systems (GNSS such as GPS / BeiDou), terrestrial cellular network base stations, wireless PTP sources, and wired time synchronization. At the fusion processing layer, a dynamic weight allocation algorithm is employed to dynamically adjust the weight of each time source in the fusion calculation based on quality indicators such as real-time availability, stability, and accuracy factors. Combined with an outlier removal mechanism, the accuracy of the fusion result is ensured. Finally, the fused time information is externally verified and "flywheeled" using a locally deployed high-precision clock. Even in the extreme case where all external time sources fail, the system can still maintain high-precision time output for a certain period of time using the local clock, thereby ensuring the highest reliability and uninterrupted operation of the time service.

[0043] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art should understand that these embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. The present invention can also be implemented through other different specific embodiments, and the details in the specification can be modified or varied based on different viewpoints and applications without departing from the spirit of the present invention.

[0044] It should be further noted that the accompanying drawings provided in the following embodiments are all schematic diagrams, intended to illustrate the basic concept of the present invention. Therefore, the drawings only show components related to the present invention, and their quantity, shape, size, and proportions may be simplified or exaggerated, and are not strictly drawn according to the form of the actual product. In some cases, in order to avoid unnecessarily obscuring the core content of the present invention, well-known structural and technical details may be omitted, or shown in block diagram form.

[0045] Example

[0046] Reference Figure 1 The system architecture of this invention is a typical wireless synchronous grid-connected detection system, including a host terminal and at least one probe terminal. In typical application scenarios such as grid-connected differential measurement, two or more probe terminals are usually included, for example, probe terminal X deployed on the main grid side and probe terminal Y deployed on the load side. The timing method described in this invention operates independently in the communication link established between the host terminal and each probe terminal. The probe terminal is responsible for collecting voltage, frequency, and zero-crossing information of the power grid line and sending data with precise timestamps to the host terminal through a 4G / 5G wireless communication module. The host terminal calculates key grid-connected parameters such as phase difference based on the data received from different probe terminals. The high-precision link timing method proposed in this invention operates in the communication and processing unit between the host terminal and the probe terminals, establishing and maintaining a high-precision time synchronization reference between the host terminal (Master) and each probe terminal (Slave).

[0047] The method flow of this invention is as follows: Figure 2 The overall process of the high-precision link timing method provided in this embodiment of the invention mainly includes the following four core steps.

[0048] Step 1: Time-varying delay adaptive compensation. This step aims to address the time-varying and severe path delay jitter problem in wireless links. The following clock dynamic state-space model is established:

[0049] Step 101: Define the system state vector ,in Indicates in The time offset of the probe's clock relative to the master clock at the host. This represents clock drift. The state equation describes the evolution of the clock state over time:

[0050]

[0051] Wherein, the state transition matrix , This represents the sampling time interval. The process noise includes clock skew and clock drift, and its covariance is... This represents the inherent uncertainty of a clock, such as frequency drift.

[0052] Step 102: By exchanging PTP protocol messages, a measurement value with noise can be obtained. This refers to the observed time shift. The measurement equation is:

[0053]

[0054] Among them, the measurement matrix . It is measurement noise, and its covariance is The noise mainly originates from the path delay jitter of the wireless link, and its statistical characteristics are time-varying.

[0055] Step 103: This invention employs an adaptive Kalman filter algorithm based on innovation, which adaptively suppresses millisecond-level random jitter by updating the process noise covariance matrix and / or measurement noise covariance matrix based on the innovation sequence. The innovation (or residual) of the filter is defined as:

[0056]

[0057] in It is a priori estimate of the current state. The theoretical covariance of the innovation is... ,in This is the prior estimation error covariance. It is estimated by measuring the covariance of the actual innovation sequence within a sliding time window:

[0058]

[0059] Given the width of the sliding time window, the real-time estimate of the measurement noise covariance is derived. :

[0060]

[0061] Real-time estimation By substituting these equations into the Kalman filter's gain calculation and state update equations, the filter can adapt to changes in measurement noise, thereby effectively suppressing delay jitter.

[0062] Step 2: Accurate Asymmetric Delay Estimation. This step aims to address the asymmetric nature of wireless link delay. (Refer to...) Figure 3 This invention constructs an augmented state model.

[0063] Step 201: Augment the state vector: reduce the asymmetric delay Introduced as a new state variable, we obtain the augmented state vector:

[0064]

[0065] in, This refers to the difference between the downlink and uplink delays at time k, which is also the asymmetric delay of the link. express Time offset at any moment, express The clock drifts at a certain moment.

[0066] Step 202 Augmented State Equation: Assuming the asymmetric delay changes slowly over a short period, it can be modeled as a random walk process. This model has extremely high accuracy in describing gradual asymmetric delays caused by network load, routing changes, etc., and this type of scenario covers more than 95% of wireless timing operation conditions. For sudden changes caused by base station hard handover, the adaptive filtering mechanism of this invention can quickly detect large innovation residuals and resolve them by resetting part of the covariance parameter or temporarily increasing the measurement noise. The value is used to accelerate the reconvergence of the filter, thus exhibiting robustness to abrupt events. A new state transition matrix is ​​used. for:

[0067]

[0068] The state equation is updated to .in, The process noise for the augmented state includes process noise from clock offset and clock drift, as well as random noise used to describe asymmetric delay variations.

[0069] Step 203 Augmented Measurement Equation: Through the PTP protocol, we can obtain two measurement quantities:

[0070]

[0071]

[0072] T1-T4 are timestamp symbols from the PTP (IEEE 1588) protocol standard, used to calculate the delay and offset of a single link:

[0073] T1: The moment when the host sends the Sync message.

[0074] T2: The moment when the probe receives the Sync message.

[0075] T3: The moment when the probe sends the Delay_Req message.

[0076] T4: The moment when the host receives the Delay_Req message.

[0077] and This represents two different observation features extracted by the same detector at time k, with calculations performed independently between different detectors.

[0078] In theory, and The relationship with the state variables is:

[0079]

[0080]

[0081] This represents the common portion of the round-trip delay in a wireless link, which is the average transmission time assuming symmetry between uplink and downlink. The individual probes'... Perform the calculations independently.

[0082] Therefore, a new measurement vector can be constructed based on the time offset. and measurement matrix Applying the new measurement vector and measurement matrix constructed from this augmented model to the adaptive Kalman filter allows for the simultaneous acquisition of the time offset in each iteration. and asymmetric delay The joint optimal estimate, thus in the calculation It automatically compensates for the effects of asymmetric delay.

[0083] Step 3: Robust transmission of timing information. To cope with wireless channel interference, this invention implements a transmission mechanism that combines active defense and passive fault tolerance.

[0084] Encoding and Encryption: Before transmission, the critical timestamp field of the authorized message is processed by a lightweight symmetric encryption algorithm (such as AES) to prevent malicious tampering. Subsequently, the entire message is encoded using LDPC to increase redundancy, and then transmitted across multiple antennas using STBC technology. This utilizes spatial diversity to combat channel fading, ensuring a bit error rate of no more than 10⁻⁻⁶. 5 Even under poor channel conditions, the receiver can still recover the original information with a high probability.

[0085] Channel Adaptation: The communication module continuously monitors the channel quality indicators (such as RSSI, SINR) of the current communication frequency. When the indicators fall below a preset threshold (for example, the interference intensity is higher than 90dB) and remain so for a period of time, the system will automatically execute the channel switching logic, either hopping to the next frequency in a pseudo-random frequency hopping sequence, or directly switching to a pre-negotiated backup channel with less interference, thereby ensuring the smooth operation of the communication link.

[0086] Step 4: Multi-source time synchronization information fusion and verification. To solve the reliability problem of a single time synchronization source, this invention designs the following... Figure 4 The layered converged architecture shown.

[0087] The data acquisition layer is constructed as follows: The hardware interface and logic design of the device are designed to simultaneously access and process four heterogeneous timing sources, specifically including: first, a GNSS source, which receives GPS / BeiDou satellite signals through an onboard GNSS module; second, a terrestrial cellular network base station source, which is obtained by parsing physical layer frame synchronization signals using a 4G / 5G communication module; third, a wireless PTP source, which is obtained by calculating based on a 4G / 5G data link and applying the high-precision timing method described in this invention; and fourth, a wired timing source, which accesses wired PTP or NTP signals through a reserved Ethernet interface as a system backup.

[0088] Fusion Processing Layer: This layer runs a dynamically weighted fusion algorithm. For time... Obtained Readings from each time source First, outliers are removed through preprocessing. Then, based on the real-time quality factor of each source... Calculate weights The quality factor can comprehensively evaluate multiple indicators, such as the number of visible satellites and DOP value of GNSS, and the covariance of the estimation error of PTP. In a preferred embodiment, different indicators can be normalized first for comprehensive evaluation. For example, the number of visible satellites... (Range 4-12) Normalized to The estimated error covariance of PTP (Assuming the range is 10⁻¹²-10⁻) 8 Normalized by logarithmic mapping to The final quality factor It can be a weighted sum of these normalization factors: ,in and The weights are preset. Those skilled in the art should understand that this is merely illustrative, and any method for dynamically calculating fusion weights based on multidimensional quality indicators should fall within the scope of protection of this invention. The fused time is:

[0089]

[0090] Verification and Output Layer: Fusion Results It will be fed into a comparator and compared with the current time of a local high-precision clock, such as a temperature-compensated crystal oscillator or a rubidium atomic clock. If the deviation is within the allowable range, then... This serves as the final system time output, with fine-tuning of the local clock. If the deviation exceeds the allowable range, or if all external sources are interrupted, the system will enter "timekeeping" mode, directly using the local high-precision clock to provide the time output, ensuring the continuity of time synchronization services.

[0091] Through the above embodiments, the present invention can provide a high-precision, high-robust, and high-reliability time synchronization solution for wireless synchronous network applications.

[0092] Based on the above method, the present invention also provides a high-precision link timing device for wireless synchronization and networking, comprising:

[0093] A time-varying delay compensation module is used to dynamically adjust the filtering parameters according to the real-time measurement error using an adaptive filtering algorithm to filter the timing information in order to suppress path delay jitter in the wireless link.

[0094] An asymmetric delay compensation module, coupled to the time-varying delay compensation module, is used to introduce the link asymmetric delay as a state variable by constructing an augmented state model based on the adaptive filtering algorithm, thereby realizing the joint estimation and compensation of clock offset and asymmetric delay.

[0095] A robust transmission module is used to perform security hardening and reliability assurance processing on the time synchronization signal, and to execute an adaptive channel selection strategy to ensure the transmission quality of the time synchronization signal;

[0096] A multi-source fusion verification module is used to fuse time information from different time sources and verify the fusion result using a local high-precision clock to improve the continuity and reliability of the time service.

[0097] Furthermore, the present invention also provides a wireless synchronous network system, comprising:

[0098] At least one host side;

[0099] At least one probe, which communicates with the host via a wireless link; and

[0100] The high-precision link timing device described above is deployed on the host end and / or the probe end to achieve time base synchronization between the probe end and the host end.

[0101] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A link timing method for wireless synchronization and networking, applied to a wireless communication system comprising a host terminal and at least one probe terminal, characterized in that: Includes the following steps: Step 1: Measure the time offset of the timing information exchanged between the host and the probe, and perform time-varying delay adaptive compensation. The compensation adopts an adaptive filtering algorithm, which dynamically adjusts the filtering parameters according to the real-time measured time offset error to suppress the path delay jitter of the wireless link. Step 2: Construct an augmented state model that includes clock state and link asymmetric delay. Introduce the link asymmetric delay as a state variable and add it together with time offset and clock drift into the adaptive filtering algorithm for joint estimation, so as to achieve joint estimation and compensation of time offset and asymmetric delay. Step 3: The timing signal is encrypted and encoded before transmission to ensure reliability. During transmission, an adaptive channel selection strategy is adopted, which adaptively hops frequency or switches to a preset backup communication channel according to the channel quality to cope with wireless link interference or network congestion. Step 4: Merge time information from different time sources and verify the fusion result using a local high-precision clock.

2. The link timing method for wireless synchronization and networking according to claim 1, characterized in that: Step 1 is as follows: Step 101: Define the system state vector ,in Indicates in The time offset of the clock at the probe end relative to the master clock at the host end. To represent clock drift, we construct state equations to describe the evolution of the clock state over time: Wherein, the state transition matrix , The sampling time interval, This is process noise; Step 102: Obtain a measurement value with noise through PTP protocol message exchange. That is, time offset, the measurement equation is: Among them, the measurement matrix , It measures noise; Step 103: Employ an innovation-based adaptive Kalman filter algorithm. Based on the noise covariance matrix of the innovation sequence update process and / or the measurement noise covariance matrix, adaptive suppression of millisecond-level random jitter is achieved. The innovation of the filter is defined as: in It is a priori estimate of the current state, and the theoretical covariance of the innovation is: in It is the prior estimation error covariance. To measure noise The covariance is estimated by considering the covariance of the actual innovation sequence within a sliding time window: Given the width of the sliding time window, the real-time estimate of the measurement noise covariance is derived. : Real-time estimation By substituting these equations into the Kalman filter's gain calculation and state update equations, the filter can adapt to changes in measurement noise and suppress delay jitter.

3. The link timing method for wireless synchronization and networking according to claim 2, characterized in that: The system monitors the innovation residual of the adaptive filtering algorithm in real time. When the innovation residual exceeds the preset threshold, it determines that a sudden event has occurred and automatically resets the filter state or adjusts the noise covariance parameter to accelerate filter convergence.

4. The link timing method for wireless synchronization and networking according to claim 1, Its characteristic is that in step 2, an augmented state model is constructed, and asymmetric delay is introduced as a state variable into the filter. Together with clock skew and clock drift, it forms an augmented state vector, thereby correcting the symmetric link assumption in the Precision Time Protocol (PTP). This includes: Step 201: Determine the augmented state vector and adjust the asymmetric delay of the link. Introduced as a state variable, we obtain the augmented state vector: in, That is, the difference between the downlink and uplink delays at time k. express Time offset at any moment, express The clock drifts at a given moment; Step 202: Construct the augmented state equation. Assume the asymmetric delay changes slowly over a short time, modeling it as a random walk process. State transition matrix... for: The state equations are updated as follows: in, For process noise in the augmented state; Step 203: Construct the augmented measurement equation and obtain two measurements of the time offset via the PTP protocol: in, It is a timestamp symbol in the PTP protocol standard, used to calculate the delay and offset of a single link; Theoretically, the relationship between the two measured quantities and the state variable is as follows: in, To calculate the average transmission time when the uplink and downlink are symmetrical, a new measurement vector is constructed based on the time offset. and measurement matrix The new measurement vectors and measurement matrices constructed using the augmented model are applied to the adaptive filtering algorithm, simultaneously obtaining the time offset in each iteration. and asymmetric delay The joint optimal estimate, thus in the calculation It automatically compensates for the effects of asymmetric delay.

5. The link timing method for wireless synchronization and networking according to claim 1, characterized in that: In step 3, before the authorization message is sent, the key timestamp field is encrypted using a lightweight symmetric encryption algorithm to prevent malicious tampering; the reliability assurance process uses a combination of low-density parity-check code (LDPC) and space-time block code (STBC) to perform robust channel coding on the authorization message. The adaptive channel selection strategy monitors channel quality in real time and triggers adaptive frequency hopping or switches to a backup channel when link deterioration exceeds a preset threshold.

6. The link timing method for wireless synchronization and networking according to claim 1, characterized in that: Step 4 is as follows: Step 401: Fusion of multi-source time synchronization information, using dynamic weight allocation, for time... Obtained Readings from each time source First, outliers are removed through preprocessing. Then, based on the real-time quality factor of each source... Calculate weights The quality indicators include the number of visible satellites, error covariance, and signal strength. The fused time is: Step 402: Merge the results The data is fed into a comparator and compared with the current time of the local high-precision clock. If the deviation is within the allowable range, then... As the final system time output, the local clock is fine-tuned; if the deviation exceeds the allowable range, or all external time sources are interrupted, the system enters "timekeeping" mode, which directly provides the time output from the local high-precision clock to ensure the continuity of time service.

7. The link timing method for wireless synchronization and networking according to claim 6, characterized in that: Multiple time synchronization sources include GPS / BeiDou satellite signals, cellular network base station sources, wired time synchronization sources, and wireless PTP sources. The quality factor of each source is first normalized and then weighted. The local high-precision clock includes a rubidium atomic clock and a temperature-compensated crystal oscillator.

8. A link timing device for wireless synchronization and networking, characterized in that: include: A time-varying delay compensation module is used to dynamically adjust the filtering parameters according to the real-time measurement error using an adaptive filtering algorithm to filter the timing information in order to suppress path delay jitter in the wireless link. An asymmetric delay compensation module, coupled to the time-varying delay compensation module, is used to introduce the link asymmetric delay as a state variable by constructing an augmented state model based on the adaptive filtering algorithm, thereby realizing the joint estimation and compensation of clock offset and asymmetric delay. A robust transmission module is used to perform security hardening and reliability assurance processing on the time synchronization signal, and to execute an adaptive channel selection strategy to ensure the transmission quality of the time synchronization signal; A multi-source fusion verification module is used to fuse time information from different time sources and verify the fusion result using a local high-precision clock to improve the continuity and reliability of the time service.

9. A wireless synchronous grid-connected system, characterized in that: include: At least one host side; At least one detection terminal, which communicates with the host terminal via a wireless link; as well as The high-precision link timing device as described in claim 8 is deployed on the host end and / or the probe end to achieve time reference synchronization between the probe end and the host end.

10. A computer-readable storage medium, characterized in that... The device contains a computer program that, when executed by a processor, implements the link timing method as described in any one of claims 1 to 7.

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