High-precision time synchronization method between high-speed motion platforms

Abstract

The application discloses a high-precision time synchronization method between high-speed motion platforms, which comprises the following steps: S1. a to-be-synchronized node sends an RTT request Req1 to a time reference node, and records a sending time T1; S2. when the time reference node receives the RTT request Req1 at a time T2, after frame processing time, the time reference node writes T2 into a response frame ACK1 and sends the response frame ACK1 to the to-be-synchronized node, and after frame processing time, the time reference node sends a response frame ACK2 to the to-be-synchronized node; S3. when the to-be-synchronized node receives ACK1 at a time T3, when the to-be-synchronized node receives ACK2, the time is T4; S4. the time offset of clock sources of two platforms before this synchronization is calculated, time synchronization is completed, and after precision synchronization, the two platforms are in a stable synchronization state of clocks. The method provided by the application effectively reduces the time synchronization error introduced by the relative motion between nodes between high-speed motion platforms, and improves the time synchronization precision between high-speed motion platforms.

Description

Technical Field

[0001] This invention relates to the field of communications, and in particular to a method for high-precision time synchronization between high-speed motion platforms. Background Technology

[0002] Since the transceiver devices used for communication are configured with different crystal oscillators to control the local time of the nodes, different crystal oscillators, even the same crystal oscillator, will produce frequency deviations over time under different physical conditions. The existence of clock deviations may cause collisions between transceiver devices at a certain moment during communication. Therefore, the entire network needs a unified time base.

[0003] The traditional RTT time synchronization algorithm is used to synchronize time information across all platforms on the network. However, due to the relative motion between nodes, the system will introduce time synchronization errors. When two nodes move at high speeds (greater than 120 km / h), the reference time will be affected by relativity. The relative motion error between nodes and the reference time error caused by the high speed of the two nodes will seriously affect the accuracy of time information synchronization. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-precision time synchronization method between high-speed motion platforms. This method reduces the time synchronization error introduced by the relative motion between nodes between motion platforms, and takes into account the time offset between nodes under the influence of high-speed motion. It corrects the time offset under the influence of high speed, effectively improving the time synchronization accuracy between high-speed motion platforms.

[0005] The objective of this invention is achieved through the following technical solution: a high-precision time synchronization method between high-speed motion platforms, comprising the following steps:

[0006] S1. For two high-speed motion platforms, one platform is designated as the node to be synchronized and the other platform is designated as the time reference node; the node to be synchronized sends an RTT request Req1 to the time reference node and records the sending time T1;

[0007] S2. When the time reference node receives the RTT request Req1 at time T2, after frame processing time t, it writes the received time T2 into the response frame ACK1 and sends it to the node to be synchronized. After another frame processing time t, it sends the response frame ACK2 to the node to be synchronized.

[0008] S3. The time when the node to be synchronized receives ACK1 is T3, and the time when the node to be synchronized receives ACK2 is T4;

[0009] S4. Calculate the time offset of the clock sources of the two nodes before this synchronization using T1, T2, T3, T4, and t to complete the time synchronization. After synchronization, the two platforms are in a stable clock synchronization state. In order to maintain the precise synchronization of the system time, the synchronization process is restarted.

[0010] The beneficial effects of this invention are: the method proposed in this invention can effectively reduce the time synchronization error between motion platforms caused by the relative motion between nodes without measuring the relative motion speed of the nodes, and takes into account the time offset between nodes under the influence of high speed, and corrects the time offset under the influence of high speed, thereby improving the time synchronization accuracy between motion platforms. Attached Figure Description

[0011] Figure 1 This is a flowchart of the method of the present invention;

[0012] Figure 2 This is a schematic diagram illustrating the principle of high-precision time synchronization between high-speed motion platforms. Detailed Implementation

[0013] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0014] like Figure 1 As shown, a high-precision time synchronization method between high-speed motion platforms includes the following steps:

[0015] S1. For two high-speed motion platforms, one platform is designated as the node to be synchronized and the other platform is designated as the time reference node; the node to be synchronized sends an RTT request Req1 to the time reference node and records the sending time T1;

[0016] S2. When the time reference node receives the RTT request Req1 at time T2, after frame processing time t, it writes the received time T2 into the response frame ACK1 and sends it to the node to be synchronized. After another frame processing time t, it sends the response frame ACK2 to the node to be synchronized.

[0017] S201. The node to be synchronized sends an RTT synchronization request Req1, which is then processed. When the time reference node receives the synchronization request Req1, it records the time as T2. After frame processing time t, it writes T2 and t into the response frame ACK1 and sends it to the node to be synchronized. Taking the node to be synchronized as the reference frame, the relationship is as follows:

[0018]

[0019] Among them, T dd This represents the time difference between the startup times of the two nodes.

[0020] From the perspective of the reference point node to be synchronized, the time when synchronization request Req1 arrived at the time base node is... However, from the perspective of a high-speed moving time reference node, the time it takes for the synchronization request Req1 to arrive at the time reference node is... Therefore, the time of time reference node T2 needs to be mapped to the corrected equation of the node to be synchronized. The corrected reference frame relation is:

[0021]

[0022] Where v is the relative velocity between nodes, and c is the speed of light;

[0023] S202. After sending response frame ACK1, send response frame ACK2. After frame processing time t, send response frame ACK2 to the node to be synchronized.

[0024] S3. The time when the node to be synchronized receives ACK1 is T3, and the time when the node to be synchronized receives ACK2 is T4;

[0025] S301. The time reference node sends an RTT synchronization request ACK1, after which... When the node to be synchronized receives the synchronization request ACK1, the time is recorded as T3. Using the node to be synchronized as the reference point, the relationship is as follows:

[0026]

[0027]

[0028] S302. The time reference node sends an RTT synchronization request ACK2, after which... When the node to be synchronized receives the synchronization request ACK2, the time is recorded as T4. Using the node to be synchronized as the reference point, the relationship is as follows:

[0029]

[0030]

[0031] S4. Calculate the time offset of the clock sources of the two nodes before this synchronization using T1, T2, T3, T4, and t to complete the time synchronization. After synchronization, the two platforms are in a stable clock synchronization state. In order to maintain the precise synchronization of the system time, the synchronization process is restarted.

[0032] Step S4 includes the following sub-steps: The node to be synchronized calculates T using T1, T2, T3, T4, t, and c. dd The results are as follows, completing high-precision time estimation.

[0033]

[0034] In the examples of this application, the working principle is as follows: Figure 2 As shown, assume there are two asynchronous platforms, platform 1 and platform 2. One platform is designated as the node to be synchronized, and the other as the time reference node. Let T... dd Let v be the time difference between the startup times of the nodes on the two platforms, and c be the speed of light. The node to be synchronized first sends an RTT request from platform 2 to the time reference node on platform 1, recording the sending time as T1; after... The time reference node at time platform 1 receives an RTT request and records the time as T2; after frame processing time t, it writes the received time T2 into the response frame ACK1 and sends it to the node to be synchronized on platform 2. Then, after... The synchronization node receives ACK1 at time T3; after frame processing time t, it sends ACK2 to the synchronization node. The time synchronization node receives ACK2 at time T4. Based on the method described in the preceding claims, the following six equations can be established regarding the above variables:

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041] Where T1, T2, T3, T4, t, and c are known quantities, the unknown quantity T can be obtained by solving the simultaneous equations. dd In the embodiments of this application, it can also be determined that and v:

[0042]

[0043]

[0044]

[0045]

[0046]

[0047] This completes the high-precision time estimation. The clock source of the node to be synchronized is added to the calculated clock offset T.dd This completes time synchronization with the time reference node.

[0048] In summary, this paper proposes a novel high-precision time synchronization method for high-speed motion platforms to address the time synchronization problem between them. This method effectively reduces the time synchronization error caused by the relative motion between nodes and improves the time synchronization accuracy between the motion platforms.

[0049] The present invention has been described in detail herein with reference to specific embodiments. The description of these embodiments is provided to enable those skilled in the art to make or apply the invention. Various modifications to these embodiments will be readily understood by those skilled in the art. The invention is not limited to these examples or some aspects thereof. The scope of the invention is defined in detail by the appended claims.

[0050] The foregoing description illustrates and describes a preferred embodiment of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A high-precision time synchronization method between high-speed motion platforms, characterized in that: Comprising the following steps: S1. For two high-speed motion platforms, taking one of the platforms as a node to be synchronized and the other as a time reference node; The time reference node sends an RTT response Respl to the node to be synchronized, and records the sending time ; S2. Time reference node receives RTT request Req1 , after frame processing time , writes the receiving time into response frame ACK1 sent to the node to be synchronized, and after frame processing time , sends response frame ACK2 to the node to be synchronized; S3. The moment when the to-be-synchronized node receives ACK1 The moment when the to-be-synchronized node receives ACK2 is ; S4. by , , , , Calculate the time offset of the two-node clock source before this synchronization, complete time synchronization, and the two platforms are in a stable synchronization state of the clock after synchronization. Step S4 includes the following sub-steps: the node to be synchronized passes... , , , , and Calculate The results are as follows, completing the high-precision time estimation: ； the clock source of the node to be synchronized is added to the calculated clock offset time synchronization with the time reference node is completed.

2. The method of claim 1, wherein: The step S2 comprises the following sub-steps: S201. The node to be synchronized sends an RTT synchronization request Req1, which is then processed. At time, the time reference node receives the synchronization request Req1 and records the time as follows. After frame processing time Afterwards, and The response frame ACK1 is written and sent to the node to be synchronized. Using the node to be synchronized as the reference point, the relationship is as follows: ； wherein, is the two-node boot-up time difference, i.e. the clock offset; The time when the synchronization request Req1 arrives at the time reference node from the perspective of the reference node to be synchronized is However, from the perspective of the time reference node that is moving at high speed, the time when the synchronization request Req1 arrives at the time reference node is Therefore, the time of the time reference node needs to be mapped to the correction equation of the node to be synchronized, and the corrected reference system relationship is: ； wherein is the relative motion speed between nodes, is the speed of light; S202. After sending the response frame ACK1, the response frame ACK2 is sent, and a frame processing time elapses The response frame ACK2 is then sent to the node to be synchronized.

3. The method of claim 1, wherein: The step S3 comprises the following sub-steps: S301. The time reference node sends an RTT synchronization request ACK1, after a certain time, the node to be synchronized receives the synchronization request ACK1, records the time as and takes the node to be synchronized as the reference system, the relationship is: ； S302. The time reference node sends an RTT synchronization request ACK2, after a certain time, the node to be synchronized receives the synchronization request ACK2, and records the time as Taking the node to be synchronized as the reference system, the relationship is: 。

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