A clock synchronization system and method for multi-source fusion of autonomous driving

Abstract

The present invention discloses a clock synchronization system and method for multi-source fusion of autonomous driving, which belongs to the field of time synchronization technology. The method specifically includes: receiving and collecting multi-source clock synchronization signals and positioning data information in the autonomous driving system, and calculating the phase difference and period difference of the clock source, solving the current signal quality based on the positioning data information, determining the confidence of the clock source based on the phase difference, period difference and signal quality of the clock source, selecting and outputting the clock source according to the current signal quality, the phase difference and period difference of the clock synchronization signal and the confidence of the clock source, correcting the clock source based on the fused clock synchronization signal, optimizing the clock synchronization calculation method, reducing the number of calculation iterations of the slave clock device during clock synchronization, reducing the fluctuation of the clock synchronization of the autonomous driving system when switching between different scenes, and improving the stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of time synchronization, and specifically relates to a clock synchronization system and method for multi-source fusion of autonomous driving. Background Art

[0002] In the field of autonomous driving, multimodal perception, prediction and control algorithms are highly dependent on the spatiotemporal information of the vehicle itself and the objects in the environment. Different types of sensors, such as lidar, millimeter-wave radar, camera, ultrasonic, etc., often have different operating frequencies and clock synchronization methods. Clock synchronization, as a basic service for autonomous driving, is particularly important to ensure that the controllers, peripherals and sensors in the system work in a coordinated and synchronous manner.

[0003] Currently, GPS / GNSS is usually used as the clock synchronization source. Satellite signals are received and processed through antennas and RTK equipment, and timing and positioning information is output to the controller device of the autonomous driving after analysis. Among them, time and positioning data are generally transmitted through the physical serial port, and the NMEA-0183 code stream and timing signal are transmitted as 1pps pulse level signal; positioning data can achieve centimeter-level accuracy, and timing signal 1PPS can achieve an accuracy of less than 100ns, which can usually achieve ns-level accuracy.

[0004] However, the PPS timing signal generated by the RTK device depends on the satellite signal. When the autonomous driving vehicle runs in an obstructed or tunnel environment, the 1PPS accuracy of the RTK device output will be reduced, or even no output during long periods of obstruction, making it difficult to ensure the normal operation of the autonomous driving system.

[0005] In addition, autonomous driving systems usually use PTP (Precision Timing Protocol, IEEE1588) and TSN (Time-Sensitive Networking, IEEE 802.1AS, gPTP) to build a master-slave clock synchronization network architecture. These two protocols can achieve 5ns-level time accuracy in wired networks, which is comparable to the performance of GPS / GNSS+RTK.

[0006] The network relies on the stability of the master clock. If ns-level time accuracy is to be achieved, the synchronization iteration process will increase the network bandwidth usage. At the same time, the hardware of the network communication equipment needs to support both protocols, resulting in high hardware costs.

[0007] For example, a Chinese patent with authorization announcement number CN105991586B discloses a multimedia clock coordination and synchronization method under heterogeneous networks. This method aims to solve the problem that existing multimedia systems and protocols lack a multi-clock compatibility mechanism, resulting in the inability to accurately integrate content and services in different networks in heterogeneous fusion networks. The method adopts a data encapsulation module, a data sending module, a data receiving module, and a data parsing and presentation module. By adding a multimedia clock coordination and synchronization mechanism, it achieves compatibility with multiple network clock synchronization mechanisms under heterogeneous networks. It adopts a unified encapsulation format for multimedia data and provides a signaling table of corresponding relationships between different clocks. This is conducive to integrating multiple network resources and improving the richness and stability of multimedia services under heterogeneous fusion networks. It is also convenient for unified management of multimedia content, reducing the time and resource waste caused by repeated encapsulation and processing of data due to different clock synchronization mechanisms, and bringing users a better service experience.

[0008] For example, the Chinese patent with publication number CN115361085A discloses an intelligent fusion terminal and time synchronization method based on dynamic weighting of multiple clock sources, including: first, the intelligent fusion terminal establishes a time synchronization model based on multiple clock sources; second, the intelligent fusion terminal obtains synchronization signals from multiple clock sources such as Beidou satellites, GPS, and ground stations by optimizing the clock source selection strategy of large time scales, and then achieves low-latency and high-precision time synchronization by optimizing the clock source weight distribution strategy of small time scales; finally, the intelligent fusion terminal provides time for unsynchronized power equipment through the timing module and the communication module. The advantages of this invention are: achieving low-latency and high-precision time synchronization of power equipment in the distribution system, reducing time synchronization errors through weighted summation, and improving time synchronization accuracy.

[0009] The defects of the above patent are: 1) It does not integrate multiple clock sources and only supports a single clock synchronization protocol; 2) It cannot perform accurate synchronization in an environment with interference and signal fluctuations. Summary of the invention

[0010] In view of the shortcomings of the prior art, the present invention proposes a clock synchronization system and method for multi-source fusion of autonomous driving, which receives and collects multi-source clock synchronization signals and positioning data information in the autonomous driving system, calculates the phase difference and period difference of the clock source, calculates the current signal quality based on the positioning data information, determines the confidence of the clock source based on the phase difference, period difference and signal quality of the clock source, selects and outputs the clock source according to the current signal quality, the phase difference and period difference of the clock synchronization signal and the confidence of the clock source, corrects the clock source based on the fused clock synchronization signal, optimizes the clock synchronization calculation method, and reduces the number of calculation iterations of the slave clock device during clock synchronization.

[0011] To achieve the above object, the present invention provides the following technical solutions:

[0012] A clock synchronization method for multi-source fusion of autonomous driving includes the following specific steps:

[0013] Receive and collect multi-source clock synchronization signals and positioning data information in the autonomous driving system, calculate the phase difference and period difference of the clock source, and calculate the current signal quality based on the positioning data information;

[0014] Determine the confidence of the clock source based on the phase difference, period difference and signal quality of the clock source;

[0015] Selecting and outputting a clock source according to the current signal quality, the phase difference and period difference of the clock synchronization signal and the confidence of the clock source;

[0016] Based on the fused clock synchronization signal, the clock source is corrected, the clock synchronization calculation method is optimized, and the number of calculation iterations of the slave clock device during clock synchronization is reduced.

[0017] Specifically, the specific steps of receiving and collecting multi-source clock synchronization signals and positioning data information in the autonomous driving system include:

[0018] Receive and collect 1PPS clock synchronization signal and positioning data information sent by RTK equipment;

[0019] Receive and collect NTP clock synchronization signals provided by the network clock server;

[0020] Receive and collect PTP / TSN clock synchronization signals provided by external devices and sensors.

[0021] Specifically, the calculating the phase difference and period difference of the clock source includes:

[0022] Calculate the phase difference of the i-th clock source. The specific formula is:

[0023] ,

[0024] in, represents the phase difference of the i-th clock source, represents the phase of the i-th clock source, Indicates the phase of the reference clock signal;

[0025] Calculate the period difference of the i-th clock source. The specific formula is:

[0026] ,

[0027] in, represents the period difference of the i-th clock source, represents the period of the i-th clock source, Indicates the period of the reference clock signal.

[0028] Specifically, the current signal quality is calculated based on the positioning data information, and the specific formula is:

[0029] ,

[0030] in, Indicates the current signal quality. , , and represents the weight coefficient, represents the average signal-to-noise ratio of the satellite, represents the maximum signal-to-noise ratio of the satellite, M represents the multipath delay, Indicates the number of visible satellites used directly, Indicates the maximum number of visible satellites. Represents the position precision factor.

[0031] Specifically, determining the confidence of the clock source includes:

[0032] Calculate the confidence of the NTP clock source and PTP / TSN clock source using the following formula:

[0033] ,

[0034] in, represents the confidence of clock source j, represents the weight factor of the phase difference, represents the weight factor of the period difference, represents the phase difference of the jth clock source, Indicates the period difference of the j-th clock source.

[0035] Specifically, the specific steps of selecting and outputting the clock source include:

[0036] Verify based on the current GPS signal quality, the confidence of the NTP clock source and the PTP / TSN clock source, and the phase difference and period difference between the clock sources;

[0037] Calculate the comprehensive score of each clock source. The comprehensive scores of 1PPS clock source, NTP clock source, and PTP / TSN clock source are: , and ;

[0038] Compare the comprehensive scores of the 1PPS clock source, NTP clock source, and PTP / TSN clock source, and select the clock source with the highest comprehensive score as the output clock.

[0039] Specifically, the clock source is corrected, the clock synchronization calculation method is optimized, and the number of calculation iterations of the slave clock device during clock synchronization is reduced. The specific steps include:

[0040] Obtain the fused clock synchronization signal from the output clock source. The specific formula for fusion of the clock synchronization signal is: ,in, Indicates the fusion clock synchronization signal, , and Respectively represent the weight coefficients of the 1PPS clock synchronization signal, the NTP clock synchronization signal, and the PTP / TSN clock synchronization signal, and satisfy , Indicates the current signal quality. Indicates the confidence of the clock source NTP. Indicates the confidence of the clock source PTP / TSN;

[0041] Estimate the deviation of the NTP clock source and PTP / TSN clock source. The calculation formula is: ,in, Indicates the deviation of the NTP clock source or PTP / TSN clock source. N indicates the number of measurements. represents the timestamp of the reference clock at the kth measurement, Indicates the timestamp of the NTP clock source or PTP / TSN clock source at the kth measurement;

[0042] Correct the deviation of the NTP clock source and PTP / TSN clock source. The specific formula is:

[0043] , Indicates the correction of the deviation of the NTP clock source and PTP / TSN clock source. t indicates the time step. represents the primary correction coefficient, represents the secondary correction coefficient, i.e. the nonlinear correction coefficient, represents the nonlinear correction function, represents the timestamp of the reference clock at time step t+1, Indicates the timestamp of the NTP clock source or PTP / TSN clock source at time step t+1. Indicates the deviation of the NTP clock source or PTP / TSN clock source at time step t+1;

[0044] For slave clock devices that use NTP clock sources, PTP / TSN clock sources for timing, the fused clock synchronization signal is used to optimize the original NTP, PTP / TSN clock synchronization calculation method and reduce the number of calculation iterations of the slave clock device during clock synchronization.

[0045] The reference clock is usually a recognized standard clock in the system;

[0046] Specifically, the optimization of the original NTP, PTP / TSN clock synchronization calculation method to reduce the number of calculation iterations of the slave clock device during clock synchronization includes:

[0047] Update the synchronization algorithm, modify the original NTP and PTP / TSN synchronization algorithms of the slave clock device, and use the fused clock signal for initial synchronization;

[0048] The fused clock signal is used as the reference time, and the slave clock devices converge during the synchronization process, reducing the number of calculation iterations.

[0049] A clock synchronization system for multi-source fusion of autonomous driving, comprising: a signal receiving and acquisition module, a confidence determination module, a clock source selection and output module, and a clock source correction and optimization module;

[0050] The signal receiving and collecting module is used to receive and collect multi-source clock synchronization signals and positioning data information in the autonomous driving system, calculate the phase difference and period difference of the clock source, and calculate the current signal quality based on the positioning data information;

[0051] The confidence determination module is used to determine the confidence of the clock source based on the phase difference, period difference and signal quality of the clock source;

[0052] The clock source selection and output module is used to select and output the clock source according to the current signal quality, the phase difference and period difference of the clock synchronization signal and the confidence of the clock source;

[0053] The clock source correction and optimization module is used to correct the clock source based on the fused clock synchronization signal, optimize the clock synchronization calculation method, and reduce the number of calculation iterations of the slave clock device during clock synchronization.

[0054] Specifically, the clock source correction and optimization module includes: a clock source correction unit and a clock source optimization unit;

[0055] The clock source correction unit is used to calculate the deviation of the clock source based on the fused clock synchronization signal and correct the clock source;

[0056] The clock source optimization unit is used to optimize the clock synchronization calculation method for the slave clock device that adopts the NTP clock, PTP / TSN clock timing, and reduce the number of calculation iterations of the slave clock device during clock synchronization.

[0057] An electronic device includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, steps of a clock synchronization method for multi-source fusion of autonomous driving are implemented.

[0058] A computer-readable storage medium stores computer instructions, which, when executed, execute the steps of a clock synchronization method for multi-source fusion of autonomous driving.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] 1. The present invention proposes a clock synchronization method for multi-source fusion of autonomous driving, which has high stability in different scenarios and can support the autonomous driving system to complete the clock synchronization of devices and sensors in the system in outdoor partially obstructed, tunnel or indoor environments.

[0061] 2. The present invention proposes a clock synchronization method for multi-source fusion of autonomous driving, which can support multiple clock synchronization protocols and facilitate the access of different devices and sensors to the clock synchronization system.

[0062] 3. The present invention proposes a clock synchronization method for multi-source fusion of autonomous driving, which can accelerate the clock synchronization process of clock sources with weak confidence, and facilitate reducing the fluctuation of clock synchronization of the autonomous driving system when switching between different scenes, thereby improving stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 A flow chart of a clock synchronization method for multi-source fusion of autonomous driving provided by the present invention;

[0064] Figure 2 A flow chart of clock source selection and output provided by the present invention;

[0065] Figure 3 A flow chart of clock source correction and optimization provided by the present invention;

[0066] Figure 4 This is a clock synchronization system architecture diagram for multi-source fusion of autonomous driving provided by the present invention;

[0067] Figure 5 A schematic diagram of an electronic device provided by the present invention;

[0068] Figure 6 A schematic diagram of the computer-readable storage medium structure provided by the present invention. DETAILED DESCRIPTION

[0069] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, in the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "No. 1", "No. 2" and "No. 3" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. The present invention is further explained below in conjunction with specific embodiments.

[0070] Example 1

[0071] See also Figures 1 to 3 , an embodiment of the present invention provides: a clock synchronization method for multi-source fusion of autonomous driving, comprising the following specific steps:

[0072] S1: Receive and collect multi-source clock synchronization signals and positioning data information in the autonomous driving system, calculate the phase difference and period difference of the clock source, and calculate the current signal quality based on the positioning data information;

[0073] The specific steps of receiving and collecting multi-source clock synchronization signals and positioning data information in the autonomous driving system include:

[0074] S101: Receive and collect 1PPS clock synchronization signal and positioning data information sent by RTK equipment;

[0075] S102: Receive and collect NTP clock synchronization signals provided by a network clock server;

[0076] S103: Receive and collect PTP / TSN clock synchronization signals provided by external devices and sensors.

[0077] Calculating the phase difference and period difference of the clock source includes:

[0078] Calculate the phase difference of the i-th clock source. The specific formula is:

[0079] ,

[0080] in, represents the phase difference of the i-th clock source, represents the phase of the i-th clock source, Indicates the phase of the reference clock signal;

[0081] Calculate the period difference of the i-th clock source. The specific formula is:

[0082] ,

[0083] in, represents the period difference of the i-th clock source, represents the period of the i-th clock source, Indicates the period of the reference clock signal.

[0084] The current signal quality is calculated based on the positioning data information. The specific formula is:

[0085] ,

[0086] in, Indicates the current signal quality. , , and represents the weight coefficient, represents the average signal-to-noise ratio of the satellite, represents the maximum signal-to-noise ratio of the satellite, M represents the multipath delay, Indicates the number of visible satellites used directly, Indicates the maximum number of visible satellites. Represents the position precision factor.

[0087] , , and It is determined by those skilled in the art through a large number of experiments.

[0088] Average signal-to-noise ratio of satellite The calculation formula is: , represents the signal-to-noise ratio of the e-th satellite, and g represents the total number of visible satellites;

[0089] The calculation formula of multipath delay M is: , represents the multipath delay of the e-th satellite;

[0090] Position Dilution of Precision The calculation formula is:

[0091] , , , and Indicates the weight of each DOP factor, GDOP represents the geometric precision factor, PDOP represents the position precision factor, VDOP represents the vertical precision factor, and HDOP represents the horizontal precision factor;

[0092] , , and It is determined by those skilled in the art through a large number of experiments.

[0093] S2: Determine the confidence level of the clock source based on the phase difference, period difference and signal quality of the clock source;

[0094] Determine the confidence level of the clock source, including:

[0095] Calculate the confidence of the NTP clock source and PTP / TSN clock source using the following formula:

[0096] ,

[0097] in, represents the confidence of clock source j, represents the weight factor of the phase difference, represents the weight factor of the period difference, represents the phase difference of the jth clock source, Indicates the period difference of the j-th clock source.

[0098] S3: selecting and outputting a clock source according to the current signal quality, the phase difference and period difference of the clock synchronization signal and the confidence of the clock source;

[0099] The specific steps for selecting and outputting the clock source include:

[0100] S301: Verify based on the current GPS signal quality, the confidence of the NTP clock source and the PTP / TSN clock source, and the phase difference and period difference between the clock sources;

[0101] S302: Calculate the comprehensive score of each clock source. The comprehensive scores of the 1PPS clock source, the NTP clock source, and the PTP / TSN clock source are: , and ;

[0102] , Indicates the weight coefficient of the number of satellites, which is used to adjust the impact of the number of satellites on the total score. If the number of satellites has a great impact on the clock source 1PPS, you can set a higher value. Indicates the position precision factor The weight coefficient is used to adjust The impact on the overall score is It has a greater impact on positioning accuracy, and you can set a higher value to reduce the score to a greater extent;

[0103] , Indicates the weight coefficient of the clock source NTP phase difference, which is used to adjust the impact of the phase difference on the total score. Indicates the weight coefficient of the NTP clock source period difference, which is used to adjust the impact of the period difference on the total score. If the phase difference and period difference of the NTP clock source have a great impact on time synchronization, these weight coefficients can be adjusted accordingly;

[0104] , Indicates the weight coefficient of the clock source PTP / TSN phase difference, which is used to adjust the impact of the phase difference on the total score. Indicates the weight coefficient of the PTP / TSN clock source period difference, which is used to adjust the impact of the period difference on the total score. If the phase difference and period difference of the PTP / TSN clock source have a great impact on time synchronization, these weight coefficients can be adjusted accordingly;

[0105] S303: Compare the comprehensive scores of the 1PPS clock source, the NTP clock source, and the PTP / TSN clock source, and select the clock source with the highest comprehensive score as the output clock.

[0106] S4: Based on the fused clock synchronization signal, the clock source is corrected, the clock synchronization calculation method is optimized, and the number of calculation iterations of the slave clock device during clock synchronization is reduced.

[0107] Correct the clock source, optimize the clock synchronization calculation method, and reduce the number of calculation iterations of the slave clock device during clock synchronization. The specific steps include:

[0108] S401: Obtain a fused clock synchronization signal from an output clock source. The specific formula for fusion of the clock synchronization signal is: ,in, Indicates the fusion clock synchronization signal, , and Respectively represent the weight coefficients of the 1PPS clock synchronization signal, the NTP clock synchronization signal, and the PTP / TSN clock synchronization signal, and satisfy , Indicates the current signal quality. Indicates the confidence of the clock source NTP. Indicates the confidence of the clock source PTP / TSN;

[0109] , and Determined by those skilled in the art through a large number of experiments;

[0110] S402: Estimate the deviation of the NTP clock source and the PTP / TSN clock source. The calculation formula is: ,in, Indicates the deviation of the NTP clock source or PTP / TSN clock source. N indicates the number of measurements. represents the timestamp of the reference clock at the kth measurement, Indicates the timestamp of the NTP clock source or PTP / TSN clock source at the kth measurement;

[0111] S403: Correct the deviation of the NTP clock source and the PTP / TSN clock source. The specific formula is:

[0112] , Indicates the correction of the deviation of the NTP clock source and PTP / TSN clock source. t indicates the time step. represents the primary correction coefficient, represents the secondary correction coefficient, i.e. the nonlinear correction coefficient, represents the nonlinear correction function, represents the timestamp of the reference clock at time step t+1, Indicates the timestamp of the NTP clock source or PTP / TSN clock source at time step t+1. Indicates the deviation of the NTP clock source or PTP / TSN clock source at time step t+1;

[0113] and Determined by those skilled in the art through a large number of experiments;

[0114] S404: For slave clock devices that use NTP clock sources and PTP / TSN clock sources for timing, the fused clock synchronization signal is used to optimize the original NTP and PTP / TSN clock synchronization calculation methods, thereby reducing the number of calculation iterations of the slave clock devices during clock synchronization.

[0115] A reference clock is usually a recognized standard clock in a system.

[0116] Optimize the original NTP, PTP / TSN clock synchronization calculation method to reduce the number of calculation iterations of the slave clock device during clock synchronization, including:

[0117] S4041: Update the synchronization algorithm, modify the original NTP and PTP / TSN synchronization algorithms of the slave clock device, and use the fused clock signal for initial synchronization;

[0118] Use the fused clock signal as the reference time in the synchronization algorithm to reduce the deviation during initial synchronization;

[0119] S4042: By using the fused clock signal as the reference time, the slave clock device can converge quickly during the synchronization process, thereby reducing the number of calculation iterations.

[0120] Example 2

[0121] See also Figure 4 , another embodiment provided by the present invention: a clock synchronization system for multi-source fusion of autonomous driving, comprising: a signal receiving and acquisition module, a confidence determination module, a clock source selection and output module and a clock source correction and optimization module;

[0122] The signal receiving and collecting module is used to receive and collect multi-source clock synchronization signals and positioning data information in the autonomous driving system, calculate the phase difference and period difference of the clock source, and calculate the current signal quality based on the positioning data information;

[0123] The confidence determination module is used to determine the confidence of the clock source based on the phase difference, period difference and signal quality of the clock source;

[0124] The clock source selection and output module is used to select and output the clock source according to the current signal quality, the phase difference and period difference of the clock synchronization signal and the confidence of the clock source;

[0125] The clock source correction and optimization module is used to correct the clock source based on the fused clock synchronization signal, optimize the clock synchronization calculation method, and reduce the number of calculation iterations of the slave clock device during clock synchronization.

[0126] The clock source correction and optimization module includes: a clock source correction unit and a clock source optimization unit;

[0127] The clock source correction unit is used to calculate the deviation of the clock source based on the fused clock synchronization signal and correct the clock source;

[0128] The clock source optimization unit is used to optimize the clock synchronization calculation method for the slave clock device that adopts the NTP clock, PTP / TSN clock timing, and reduce the number of calculation iterations of the slave clock device during clock synchronization.

[0129] Example 3

[0130] Figure 5 1 is a schematic diagram of the structure of an electronic device provided by an embodiment of the present application. Figure 5 As shown, according to another aspect of the present application, an electronic device 500 is also provided. The electronic device 500 may include one or more processors and one or more memories. The memory stores a computer readable code, and when the computer readable code is executed by one or more processors, a clock synchronization method for multi-source fusion of autonomous driving can be executed.

[0131] The method or system according to the embodiment of the present application can also be used by Figure 5The electronic device architecture shown in FIG. Figure 5 As shown, the electronic device 500 may include a bus 501, one or more CPUs 502, ROM 503, RAM 504, a communication port 505 connected to a network, an input / output component 506, a hard disk 507, etc. The storage device in the electronic device 500, such as ROM 503 or hard disk 507, may store a clock synchronization method for multi-source fusion of autonomous driving provided by the present application. A clock synchronization method for multi-source fusion of autonomous driving may, for example, include: collecting and annotating a large number of geometric constraint problems and solutions to form a training data set and a fine-tuning data set; receiving and collecting multi-source clock synchronization signals and positioning data information in the autonomous driving system, and calculating the phase difference and period difference of the clock source, and solving the current signal quality based on the positioning data information; determining the confidence of the clock source based on the phase difference, period difference and signal quality of the clock source; selecting and outputting the clock source according to the current signal quality, the phase difference, period difference of the clock synchronization signal and the confidence of the clock source; based on the fused clock synchronization signal, correcting the clock source, optimizing the clock synchronization calculation method, and reducing the number of calculation iterations of the slave clock device during clock synchronization. Furthermore, the electronic device 500 may also include a user interface 508. Figure 5 The architecture shown is only exemplary and can be omitted according to actual needs when implementing different devices. Figure 5 One or more components of an electronic device are shown.

[0132] Example 4

[0133] Figure 6 Schematic diagram of a computer-readable storage medium structure provided by an embodiment of the present application. Figure 6 As shown, a computer-readable storage medium 600 according to an embodiment of the present application is shown. Computer-readable instructions are stored on the computer-readable storage medium 600. When the computer-readable instructions are executed by the processor, a clock synchronization method for multi-source fusion of autonomous driving according to an embodiment of the present application described with reference to the above figures can be executed. The storage medium 600 includes, but is not limited to, for example, volatile memory and / or non-volatile memory. Volatile memory may include, for example, random access memory (RAM) and cache memory (cache). Non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc.

[0134] It should be understood that the methods, apparatuses, and devices of the present application can be implemented in many ways. For example, the methods, apparatuses, and devices of the present application can be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above order of steps for the method is only for illustration, and the steps of the method of the present application are not limited to the order specifically described above unless otherwise specified. In addition, in some embodiments, the present application can also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present application. Therefore, the present application also covers a recording medium storing a program for executing the method according to the present application.

[0135] In addition, the parts of the above-mentioned technical solutions provided in the embodiments of the present application that are consistent with the implementation principles of the corresponding technical solutions in the prior art are not described in detail to avoid excessive redundancy.

[0136] The specific implementation modes as described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation mode of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A clock synchronization method for multi-source fusion of autonomous driving, characterized in that: include: Receive and collect multi-source clock synchronization signals and positioning data information in the autonomous driving system, calculate the phase difference and period difference of the clock source, and calculate the current signal quality based on the positioning data information; Determine the confidence of the clock source based on the phase difference, period difference and signal quality of the clock source; Selecting and outputting a clock source according to the current signal quality, the phase difference and period difference of the clock synchronization signal and the confidence of the clock source; Based on the fused clock synchronization signal, the clock source is corrected, the clock synchronization calculation method is optimized, and the number of calculation iterations of the slave clock device during clock synchronization is reduced; The specific steps of selecting and outputting the clock source include: Verify based on the current GPS signal quality, the confidence of the NTP clock source and the PTP / TSN clock source, and the phase difference and period difference between the clock sources; Calculate the comprehensive score of each clock source. The comprehensive scores of 1PPS clock source, NTP clock source, and PTP / TSN clock source are: , and ; Compare the comprehensive scores of the 1PPS clock source, NTP clock source, and PTP / TSN clock source, and select the clock source with the highest comprehensive score as the output clock; The clock source is corrected, the clock synchronization calculation method is optimized, and the number of calculation iterations of the slave clock device during clock synchronization is reduced. The specific steps include: Obtain the fused clock synchronization signal from the output clock source. The specific formula for fusion of the clock synchronization signal is: ,in, Indicates the fusion clock synchronization signal, , and Respectively represent the weight coefficients of the 1PPS clock synchronization signal, the NTP clock synchronization signal, and the PTP / TSN clock synchronization signal, and satisfy , Indicates the current signal quality. Indicates the confidence of the clock source NTP. Indicates the confidence of the clock source PTP / TSN; Estimate the deviation of the NTP clock source and PTP / TSN clock source. The calculation formula is: ,in, Indicates the deviation of the NTP clock source or PTP / TSN clock source. N indicates the number of measurements. represents the timestamp of the reference clock at the kth measurement, Indicates the timestamp of the NTP clock source or PTP / TSN clock source at the kth measurement; Correct the deviation of the NTP clock source and PTP / TSN clock source. The specific formula is: , Indicates the correction of the deviation of the NTP clock source and PTP / TSN clock source. t indicates the time step. represents the primary correction coefficient, represents the secondary correction coefficient, i.e. the nonlinear correction coefficient, represents the nonlinear correction function, represents the timestamp of the reference clock at time step t+1, Indicates the timestamp of the NTP clock source or PTP / TSN clock source at time step t+1. Indicates the deviation of the NTP clock source or PTP / TSN clock source at time step t+1; For slave clock devices that use NTP clock sources, PTP / TSN clock sources for timing, the fused clock synchronization signal is used to optimize the original NTP, PTP / TSN clock synchronization calculation method and reduce the number of calculation iterations of the slave clock device during clock synchronization.

2. A clock synchronization method for multi-source fusion of autonomous driving according to claim 1, characterized in that: The specific steps of receiving and collecting multi-source clock synchronization signals and positioning data information in the autonomous driving system include: Receive and collect 1PPS clock synchronization signal and positioning data information sent by RTK equipment; Receive and collect NTP clock synchronization signals provided by the network clock server; Receive and collect PTP / TSN clock synchronization signals provided by external devices and sensors.

3. A clock synchronization method for multi-source fusion of autonomous driving according to claim 1, characterized in that: The calculating the phase difference and period difference of the clock source comprises: Calculate the phase difference of the i-th clock source. The specific formula is: ， in, represents the phase difference of the i-th clock source, represents the phase of the i-th clock source, Indicates the phase of the reference clock signal; Calculate the period difference of the i-th clock source. The specific formula is: ， in, represents the period difference of the i-th clock source, represents the period of the i-th clock source, Indicates the period of the reference clock signal.

4. The clock synchronization method for multi-source fusion of autonomous driving according to claim 1, characterized in that: The specific formula for calculating the current signal quality based on the positioning data information is: ， in, Indicates the current signal quality. , , and represents the weight coefficient, represents the average signal-to-noise ratio of the satellite, represents the maximum signal-to-noise ratio of the satellite, M represents the multipath delay, Indicates the number of visible satellites used directly, Indicates the maximum number of visible satellites. Represents the position precision factor.

5. The clock synchronization method for multi-source fusion of autonomous driving according to claim 1, characterized in that: The determining the confidence of the clock source includes: Calculate the confidence of the NTP clock source and PTP / TSN clock source using the following formula: ， in, represents the confidence of clock source j, represents the weight factor of the phase difference, represents the weight factor of the period difference, represents the phase difference of the jth clock source, Indicates the period difference of the j-th clock source.

6. A clock synchronization method for multi-source fusion of autonomous driving according to claim 1, characterized in that: The optimization of the original NTP, PTP / TSN clock synchronization calculation method reduces the number of calculation iterations of the slave clock device during clock synchronization, including: Update the synchronization algorithm, modify the original NTP and PTP / TSN synchronization algorithms of the slave clock device, and use the fused clock signal for initial synchronization; The fused clock signal is used as the reference time, and the slave clock devices converge during the synchronization process, reducing the number of calculation iterations.

7. A clock synchronization system for multi-source fusion of autonomous driving, which is implemented based on a clock synchronization method for multi-source fusion of autonomous driving according to any one of claims 1 to 6, characterized in that: include: Signal receiving and acquisition module, confidence determination module, clock source selection and output module and clock source correction and optimization module; The signal receiving and collecting module is used to receive and collect multi-source clock synchronization signals and positioning data information in the autonomous driving system, calculate the phase difference and period difference of the clock source, and calculate the current signal quality based on the positioning data information; The confidence determination module is used to determine the confidence of the clock source based on the phase difference, period difference and signal quality of the clock source; The clock source selection and output module is used to select and output the clock source according to the current signal quality, the phase difference and period difference of the clock synchronization signal and the confidence of the clock source; The clock source correction and optimization module is used to correct the clock source based on the fused clock synchronization signal, optimize the clock synchronization calculation method, and reduce the number of calculation iterations of the slave clock device during clock synchronization.

8. A clock synchronization system for multi-source fusion of autonomous driving according to claim 7, characterized in that: The clock source correction and optimization module includes: a clock source correction unit and a clock source optimization unit; The clock source correction unit is used to calculate the deviation of the clock source based on the fused clock synchronization signal and correct the clock source; The clock source optimization unit is used to optimize the clock synchronization calculation method for the slave clock device that adopts the NTP clock, PTP / TSN clock timing, and reduce the number of calculation iterations of the slave clock device during clock synchronization.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of a clock synchronization method for multi-source fusion of autonomous driving described in any one of claims 1-6 are implemented.

10. A computer-readable storage medium, characterized in that: Computer instructions are stored thereon, and when the computer instructions are executed by a processor, the steps of a clock synchronization method for multi-source fusion of autonomous driving described in any one of claims 1-6 are executed.

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