CN114978397A

CN114978397A - Clock and frequency synchronization method and device for automatically driving whole vehicle and electronic equipment

Info

Publication number: CN114978397A
Application number: CN202210529019.XA
Authority: CN
Inventors: 荆帅; 曹斌
Original assignee: Neusoft Reach Automotive Technology Shanghai Co Ltd
Current assignee: Neusoft Reach Automotive Technology Shanghai Co Ltd
Priority date: 2022-05-16
Filing date: 2022-05-16
Publication date: 2022-08-30

Abstract

The invention provides a clock and frequency synchronization method and device for automatically driving a whole vehicle and electronic equipment, wherein the clock and frequency synchronization method and device comprise the following steps: determining an external clock source reference under different scene working conditions; and performing clock and frequency synchronization among the intelligent networking unit, the central control unit, the intelligent driving unit, the intelligent cabin unit and the sub-function system by adopting a gPTP protocol stack based on the external clock source reference. The synchronization method can realize the clock and frequency synchronization of the automatic driving whole vehicle, has high synchronization precision, and solves the technical problem that the clock and frequency synchronization of the automatic driving whole vehicle cannot be realized in the prior art.

Description

Clock and frequency synchronization method and device for automatically driving whole vehicle and electronic equipment

Technical Field

The invention relates to the technical field of automatic driving, in particular to a clock and frequency synchronization method and device for an automatic driving whole vehicle and electronic equipment.

Background

In recent years, the automatic driving technology has become the most active topic in the world, and when the automatic driving vehicle needs to complete a series of complex functions such as highway autonomous cruise, garage intelligent parking and the like, the real-time requirement between controllers in different domains is necessarily high. If the clock and frequency synchronization between the controllers in different domains is not well done, great time delay and control disorder can be brought, thus threatening the driving safety and even endangering the lives of drivers and passengers.

For example, when an automatically-driven vehicle travels in an automatic driving mode, the situation that the position of the vehicle deviates from a lane line at a certain time occurs, if clocks of the intelligent driving unit and the intelligent network unit are not synchronous, the vehicle position information with a timestamp sent by the intelligent network unit is a three-dimensional coordinate of 10:00:00, the clock of the intelligent network unit at the moment is 10:00:00, and after the intelligent driving unit receives the information, the condition that 10:00: when the vehicle deviates from the lane at 00 hours, the current clock of the vehicle is 9:59:00 (because the vehicle position does not deviate from the lane at 9:59:00 hours, the lane can be automatically corrected to cause the vehicle to deviate from the lane), then the lane correction can not be immediately carried out through the vehicle body control, the lane correction can be carried out when the clock of the vehicle reaches 10:00:00 hours, at the moment, the control operation can generate 1 minute delay, namely the automatic correction of the lane position after 1 minute delay can not avoid the occurrence of accidents, and therefore, the driving safety problem caused by the asynchronous clock of the intelligent driving unit and the intelligent network connection unit can occur.

At present, clock synchronization related to automatic driving is realized in a single domain controller (for example, realized in an intelligent driving unit), and clock and frequency synchronization of an automatic driving whole vehicle cannot be realized, so how to realize clock and frequency synchronization of the automatic driving whole vehicle becomes a technical problem which needs to be solved at present.

Disclosure of Invention

In view of this, the present invention provides a method, an apparatus, and an electronic device for synchronizing a clock and a frequency of an automatically driven vehicle, so as to solve the technical problem that the clock and the frequency of the automatically driven vehicle cannot be synchronized in the prior art.

In a first aspect, an embodiment of the present invention provides a method for synchronizing a clock and a frequency of an automatically driven whole vehicle, where the automatically driven whole vehicle includes: the intelligent network connection unit, the central control unit, the intelligent driving unit, the intelligent cockpit unit and the sub-function system all follow an ARM Cortex architecture, wherein an M core of the intelligent network connection unit deploys a gPTP Grandmaster master node, an M core of the central control unit deploys a gPTP Grandmaster slave node and a gPTP Bridge master node, an M core and an R core of the intelligent driving unit both deploy a gPTP Bridge slave node and a gPTP End Point master node, an A core of the intelligent driving unit deploys a gPTP End Point slave node, an M core of the intelligent cockpit unit deploys a gPTP Bridge slave node and a gPTP End Point master node, and the sub-function system deploys a gPTP End Point slave node, the method comprises the following steps:

determining an external clock source reference under different scene working conditions;

and executing clock and frequency synchronization among the intelligent networking unit, the central control unit, the intelligent driving unit, the intelligent cabin unit and the sub-function system by adopting a gPTP protocol stack based on the external clock source reference.

Further, under different scene conditions, determining an external clock source reference includes:

when the number of GNSS satellites observed by the GNSS antenna of the automatic driving whole vehicle is not less than 4, taking a GNSS clock obtained by positioning and resolving of a GNSS receiver as the reference of the external clock source;

when the number of GNSS satellites observed by the GNSS antenna of the automatic driving whole vehicle is less than 4, taking an atomic clock of any observed GNSS satellite as the reference of the external clock source;

when the GNSS antenna of the automatic driving vehicle can not observe any GNSS satellite, acquiring a network clock through a modem of the intelligent network connection unit, and taking the network clock as the reference of the external clock source;

and when the GNSS antenna of the automatic driving whole vehicle can not observe any GNSS satellite and no network coverage exists in the area where the automatic driving whole vehicle is located, determining the external clock source reference based on the clock when the signal of the GNSS satellite and the network signal are lost simultaneously.

Further, determining the external clock source reference based on the clock when the signal of the GNSS satellite and the network signal are simultaneously lost includes:

taking a clock when the signals of the GNSS satellite and the network signals are lost simultaneously as an initial clock;

calculating the current clock according to the starting clock, the oscillation frequency and the oscillation period of a crystal oscillator in the intelligent networking unit;

and taking the current clock as the external clock source reference.

Further, performing clock and frequency synchronization among the intelligent networking unit, the central control unit, the intelligent driving unit, the intelligent cabin unit and the sub-function system by using a gPTP protocol stack based on the external clock source reference, including:

clock and frequency synchronization between the M core of the intelligent network connection unit and the M core of the central control unit is completed through clock synchronization message transceiving between the gPTP Grandmaster master node and the gPTP Grandmaster slave node, wherein the gPTP Grandmaster master node is used for acquiring the external clock source reference;

clock and frequency synchronization between the M core of the central control unit and the M core of the intelligent driving unit, and clock and frequency synchronization between the M core of the central control unit and the M core of the intelligent cabin unit are completed through clock synchronization message transceiving between the gPTP Bridge master node and the gPTP Bridge slave node;

and completing the R core of the intelligent driving unit, the clock and frequency synchronization between the M core of the intelligent driving unit and the A core of the intelligent driving unit, and the clock and frequency synchronization between the M core of the intelligent cabin unit and the sub-function system by receiving and transmitting clock synchronization messages between the gPTP End Point master node and the gPTP End Point slave node.

Further, the method further comprises:

calculation formula A by clock synchronization precision _ts Calculating clock synchronization accuracy, wherein α represents an external coincidence accuracy, the external coincidence accuracy is 10-20ns when the external clock source reference is a GNSS clock or an atomic clock of a GNSS satellite, the external coincidence accuracy is 1.5 μ s when the external clock source reference is a network clock, β represents an internal coincidence accuracy, the internal coincidence accuracy β is B n, and B represents the same time of a gPTP protocol stackStep precision, n denotes the number of transmissions of the gPTP protocol stack, γ denotes a margin, γ ═ α + β × b, and b denotes a preset percentage value.

Further, the method further comprises:

acquiring a message which is sent by a target domain controller and carries a timestamp;

judging whether the delay of the message is overtime or not based on the timestamp;

if overtime, discarding the message;

and if not, using the message.

Further, determining whether the delay of the message is overtime based on the timestamp includes:

calculating a time difference according to the timestamp and the current clock time of the domain controller;

if the time difference is larger than a preset threshold value, determining that the delay of the message is overtime;

and if the time difference is not larger than the preset threshold, determining that the delay of the message is not overtime.

In a second aspect, an embodiment of the present invention further provides a clock and frequency synchronization apparatus for an automatic driving entire vehicle, where the automatic driving entire vehicle includes: the intelligent network unit, the central control unit, the intelligent driving unit, the intelligent cockpit unit and the sub-function system all follow an ARM Cortex architecture, wherein an M core of the intelligent network unit deploys a gpptp Grandmaster master node, an M core of the central control unit deploys a gpptp Grandmaster slave node and a gPTP Bridge master node, an M core and an R core of the intelligent driving unit both deploy a gPTP Bridge slave node and a gPTP End Point master node, an a core of the intelligent driving unit deploys a gPTP End Point slave node, an M core of the intelligent cockpit unit deploys a gPTP Bridge slave node and a gPTP End Point master node, the sub-function system deploys a gPTP End Point slave node, and the device comprises:

the determining unit is used for determining the external clock source reference under different scene working conditions;

and the execution unit is used for executing clock and frequency synchronization among the intelligent network connection unit, the central control unit, the intelligent driving unit, the intelligent cabin unit and the sub-function system by adopting a gPTP (gigabit time protocol) stack based on the external clock source reference.

In a third aspect, an embodiment of the present invention further provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor implements the steps of the method according to any one of the above first aspects when executing the computer program.

In a fourth aspect, embodiments of the present invention also provide a computer-readable storage medium storing machine executable instructions, which when invoked and executed by a processor, cause the processor to perform the method of any of the first aspect.

In the embodiment of the invention, a method for synchronizing a clock and a frequency of an automatic driving whole vehicle is provided, wherein the automatic driving whole vehicle comprises the following steps: the intelligent driving system comprises an intelligent networking unit, a central control unit, an intelligent driving unit, an intelligent cabin unit and a sub-function system, wherein the intelligent networking unit, the central control unit, the intelligent driving unit and the intelligent cabin unit all follow an ARM Cortex architecture, a gPTP Grandmaster node is deployed in an M core of the intelligent networking unit, a gPTP Grandmaster node and a gPTP Bridge master node are deployed in an M core of the central control unit, a gPTP Bridge slave node and a gPTP End Point master node are deployed in an M core and an R core of the intelligent driving unit, a gPTP End Point slave node is deployed in an A core of the intelligent driving unit, a gPTP End Point slave node and a gPTP End Point master node are deployed in an M core of the intelligent cabin unit, and a gPTP End Point slave node is deployed in a sub-function system, and the method comprises the following steps: determining an external clock source reference under different scene working conditions; and performing clock and frequency synchronization among the intelligent networking unit, the central control unit, the intelligent driving unit, the intelligent cabin unit and the sub-function system by adopting a gPTP protocol stack based on the external clock source reference. According to the description, the clock and frequency synchronization method for the automatic driving whole vehicle can realize the clock and frequency synchronization of the automatic driving whole vehicle, has high synchronization precision, and solves the technical problem that the clock and frequency synchronization of the automatic driving whole vehicle cannot be realized in the prior art.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a flowchart of a synchronization method for automatically driving a clock and a frequency of a whole vehicle according to an embodiment of the present invention;

FIG. 2 is an architecture diagram of clock and frequency synchronization for an autonomous driving vehicle according to an embodiment of the present invention;

fig. 3 is a flowchart of a method for determining a reference of an external clock source according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a clock and frequency synchronization device for automatically driving a whole vehicle according to an embodiment of the present invention;

fig. 5 is a schematic diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

At present, clock synchronization related to automatic driving is realized in a single domain controller (for example, realized in an intelligent driving unit), and clock and frequency synchronization of an automatic driving whole vehicle cannot be realized.

Based on the clock and frequency synchronization method of the automatic driving whole vehicle, the clock and frequency synchronization of the automatic driving whole vehicle can be realized, and the synchronization precision is high.

In order to facilitate understanding of the embodiment, a detailed description is first given of a clock and frequency synchronization method for automatically driving a whole vehicle, which is disclosed in the embodiment of the present invention.

The first embodiment is as follows:

it should be noted that, although a logical order is shown in the flow chart, in some cases, the steps shown or described may be performed in an order different from the order shown or described herein.

Fig. 1 is a flowchart of a synchronization method for automatically driving a clock and a frequency of a whole vehicle according to an embodiment of the present invention, as shown in fig. 1, the method includes the following steps:

step S102, determining external clock source reference under different scene working conditions;

in the embodiment of the present invention, referring to fig. 2, the automatic driving of the entire vehicle includes: the intelligent network unit, the central control unit, the intelligent driving unit, the intelligent cabin unit and the sub-function system all follow an ARM Cortex architecture, wherein a gPTP Grandmaster node is deployed in an M core of the intelligent network unit, a gPTP Grandmaster slave node and a gPTP Bridge master node are deployed in an M core of the central control unit, a gPTP Bridge slave node and a gPTP End master node are deployed in an M core and an R core of the intelligent driving unit, a gPTP End Point slave node is deployed in an A core of the intelligent driving unit, a gPTP edge slave node and a gPTP End Point master node are deployed in an M core of the intelligent cabin unit, and a gPTP End Point slave node is deployed in a sub-function system.

Specifically, the clock and frequency synchronization method for the automatic driving whole vehicle realizes time synchronization and frequency synchronization between controllers in different domains of the automatic driving whole vehicle by means of the current mature generalized precise clock protocol (gPTP). The gPTP protocol stack includes: the method comprises the following steps of three types of gPTP Grandmaster, gPTP Bridge and gPTP End Point, wherein a protocol stack for directly obtaining the reference of an external clock source is called gPTP Grandmaster; the protocol stack which plays a gateway routing function in clock and frequency synchronization is called gPTP Bridge, and the gPTP Bridge receives the clock synchronization message at the upstream and synchronizes the clock synchronization message to other units at the downstream; the protocol stack that receives only the upstream clock synchronization messages and does not need to communicate with the downstream is called gPTP End Point. Each protocol stack is divided into a master node and a slave node, the master node and the slave node of the same protocol stack are deployed in different domain control units (see fig. 2 specifically), synchronization of ethernet clocks and frequencies between upstream and downstream domain control units is realized, and a specific method for clock and frequency synchronization can refer to the gPTP technical principle (IEEE Std 802.1 AS).

The intelligent network unit, the central control unit, the intelligent driving unit and the intelligent cabin unit all follow an ARM Cortex architecture and are domain control units (or domain controllers), wherein a core A (Cortex-A) is a performance core, is oriented to a performance-intensive system and mainly meets the requirement of high computational power; the R core (Cortex-R) faces to a real-time system, and has higher requirements on real-time performance and reliability; the M core (Cortex-M) is a Microcontroller (MCU) and mainly faces to embedded application, and requirements on instantaneity and reliability are high. Each unit comprises at least one semiconductor chip, and each unit comprises an A core, an R core and an M core, so that the M cores of the intelligent networking unit, the central control unit, the intelligent driving unit and the intelligent cabin unit have high requirements on real-time performance and reliability, therefore, the M cores of the units need to synchronize the clock and the frequency, that is, nodes of the gPTP related protocol stack need to be deployed in the M cores of the units, and in addition, considering that the a core of the intelligent driving unit needs to assume the function of sensing, therefore, higher clock and frequency synchronization accuracy is also required, otherwise, a sensing delay can cause a safety accident that an automatic driving reaction is not timely, that is, the core a of the intelligent driving unit also needs to deploy nodes of the gPTP related protocol stack, and similarly, the core R of the intelligent driving unit also needs to deploy nodes of the gPTP related protocol stack.

The above-mentioned sub-functional system includes at least: a driver distraction monitoring system and a steering wheel hands-off detection system.

It should be noted that, under different scene conditions, the method of the present invention can determine to obtain a more accurate external clock source reference, and the process is described in detail below, which is not described herein again.

The external clock source reference is determined, and the clock and frequency synchronization is carried out on the external clock source reference, so that the vehicle-road cooperation can be conveniently realized in the later period. Because only each automatic driving vehicle is synchronized by the clock and frequency based on the unified external clock source, the clock and frequency synchronization between all automatic driving vehicles can be realized, and the same time reference is used for the communication between the vehicles and between the vehicle and other things (such as road facilities, traffic lights and the like), so that the effective high-precision real-time data communication can be realized.

And step S104, performing clock and frequency synchronization among the intelligent networking unit, the central control unit, the intelligent driving unit, the intelligent cabin unit and the sub-function system by adopting a gPTP protocol stack based on an external clock source reference.

The process will be described in detail below, and will not be described herein.

The above description briefly introduces the clock and frequency synchronization method of the autonomous driving vehicle of the present invention, and the details thereof are described in detail below.

In an optional embodiment of the present invention, referring to fig. 3, in different scene conditions, determining the external clock source reference specifically includes the following steps:

step S301, when the number of GNSS satellites observed by the GNSS antenna of the self-propelled vehicle is not less than 4, taking a GNSS clock obtained during positioning calculation of the GNSS receiver as an external clock source reference;

specifically, when the whole automatic driving vehicle is in a completely open scene, the number of GNSS satellites (including GPS satellites, beidou satellites, or other navigation satellites) observed by the GNSS antenna deployed on the shark fin is not less than 4, so that satellite signals received by the GNSS antenna can be positioned and resolved by the GNSS receiver, the three-dimensional coordinates of the whole vehicle and the GNSS clock are resolved, and the GNSS clock obtained by positioning and resolving is used as an external clock source reference.

The GNSS clock comprises a GNSS week and a second in week.

Step S302, when the number of GNSS satellites observed by the GNSS antenna of the self-propelled vehicle is less than 4, taking the atomic clock of any observed GNSS satellite as the external clock source reference;

specifically, when the whole automatic driving vehicle is in a partially shielded scene, the number of GNSS satellites (including GPS satellites, beidou satellites, or other navigation satellites) observed by the GNSS antenna deployed on the shark fin is less than 4, and at this time, an atomic clock of any observed GNSS satellite can be used as an external clock source reference.

Step S303, when the GNSS antenna of the self-driving vehicle can not observe any GNSS satellite, acquiring a network clock through a modem of the intelligent network connection unit, and taking the network clock as an external clock source reference;

specifically, when the automatic driving vehicle is in a completely shielded scene, the GNSS antenna cannot observe any GNSS satellite, that is, the GNSS antenna cannot receive any satellite signal, at this time, the network clock (4G/5G network clock) can be acquired through the modem of the intelligent network connection unit (T-Box), and the network clock is used as an external clock source reference.

Step S304, when the GNSS antenna of the automatic driving whole vehicle can not observe any GNSS satellite and the area of the automatic driving whole vehicle has no network coverage, determining the external clock source reference based on the clock when the signal of the GNSS satellite and the network signal are lost simultaneously.

Specifically, when the whole automatic driving vehicle is in a completely-shielded and network-coverage-free scene, the external clock source reference is determined based on the clock when the signal of the GNSS satellite and the network signal are lost simultaneously (the clock immediately before the signal of the GNSS satellite and the network signal are lost simultaneously).

Specifically, a clock when the GNSS satellite signal and the network signal are simultaneously lost is used as a start clock; calculating a current clock according to the initial clock, the oscillation frequency and the oscillation period of a crystal oscillator in the intelligent networking unit; and taking the current clock as an external clock source reference.

The current clock tn is t0+ ω n, where tn denotes the current clock, t0 denotes a start clock, ω denotes an oscillation frequency of a crystal oscillator in the smart grid-connected unit, and n denotes an oscillation period, and the start clock and the oscillation frequency are both accurate, so that the calculated current clock, i.e., the external clock source reference, is also accurate.

It should be noted that, the determination of the external clock source reference in the above steps S301 to S303 is implemented by the module of arbitrating the external clock source, and the step S303 can be implemented by the whole intelligent networking unit.

In an optional embodiment of the present invention, a gPTP protocol stack is used to perform clock and frequency synchronization between the intelligent networking unit, the central control unit, the intelligent driving unit, the intelligent cabin unit, and the sub-function system based on an external clock source reference, which specifically includes:

(1) clock and frequency synchronization between an M core of an intelligent network connection unit and an M core of a central control unit is completed through receiving and transmitting clock synchronization messages between a gPTP Grandmaster node and a gPTP Grandmaster slave node, wherein the gPTP Grandmaster node is used for acquiring an external clock source reference;

the clock synchronization messaging (i.e., the clock synchronization signal in fig. 2) includes: and the gPTP Grandmaster master node sends a clock synchronization request message to the gPTP Grandmaster slave node, and the gPTP Grandmaster slave node returns a clock synchronization response message to the gPTP Grandmaster node.

The process of clock and frequency synchronization is briefly described as follows:

the time when the gPTP Grandmaster node sends the clock synchronization request message is T1, the time when the gPTP Grandmaster slave node receives the clock synchronization request message is T2, the time when the gPTP Grandmaster slave node returns the clock synchronization response message is T3, and the time when the gPTP Grandmaster node receives the clock synchronization response message is T4, so that the time synchronization precision (namely the transmission time of the primary message) of the gPTP protocol stack is as follows: b ═ [ (T2-T1) + (T4-T3) ]/2, frequency ratio of gPTP protocol stack: r ═ T2-T1)/(T4-T3.

In addition to the above definitions, the present invention also provides another definition, specifically: the time interval from the time when the gpptp Grandmaster master node sends the clock synchronization request message to the time when the gpptp Grandmaster slave node receives the clock synchronization request message is denoted as t1, the time interval from the time when the gpptp Grandmaster slave node returns the clock synchronization response message to the time when the gpptp Grandmaster node receives the clock synchronization response message is denoted as t2, the time interval from the time when the gpptp Grandmaster node sends the clock synchronization request message every two adjacent times is denoted as t3, and the time interval from the time when the gpptp Grandmaster slave node receives the clock synchronization request message every two adjacent times is denoted as t4, so that the time synchronization accuracy of the gPTP protocol stack (i.e., the transmission time of the primary message) is: b ═ 2 (t1+ t2), frequency ratio of the gPTP protocol stack: and R is t3/t 4.

The clock synchronization is a strategy of adjusting the time reference of the slave node to be 0 as much as possible, specifically, T2 is adjusted to be close to T1, and T3 is adjusted to be close to T4, and the frequency synchronization is a strategy of controlling R to be 1, and when R is greater than 1 or less than 1, the slave node adjusts the time reference of the slave node to be 1as much as possible. Even if clock synchronization is performed, a certain time error still exists, and the time synchronization precision of the gPTP protocol stack is generally 30-50 ns. In addition, the frequency synchronization of the gPTP requires the slave node to perform calibration with the frequency of the master node as a reference, and when the clock synchronization message is received and transmitted, the clock synchronization and the frequency synchronization are completed at the same time.

It should be noted that: the clock synchronization message carries information of an external clock source reference, that is, when clock synchronization is performed, synchronization is performed based on the external clock source reference, even if the clocks of the domain control units are based on the external clock source.

After clock and frequency synchronization between the gPTP Grandmaster master node and the gPTP Grandmaster slave node is completed, the gPTP Grandmaster slave node and the gPTP Bridge master node in the same structural body (M core of the central control unit) realize clock and frequency synchronization at the same time.

(2) Clock and frequency synchronization between M cores of a central control unit, clock and frequency synchronization between M cores of the central control unit and an intelligent driving unit, and clock and frequency synchronization between the M cores of the central control unit and an intelligent cabin unit are completed through clock synchronization message transceiving between a gPTP Bridge master node and a gPTP Bridge slave node;

the clock synchronization message also carries information of an external clock source reference, and the specific process refers to the description in (1) above, which is not described herein again.

(3) And completing the clock and frequency synchronization between the R core of the intelligent driving unit, the M core of the intelligent driving unit and the A core of the intelligent driving unit and the clock and frequency synchronization between the M core of the intelligent cabin unit and the sub-function system by receiving and transmitting clock synchronization messages between the gPTP End Point master node and the gPTP End Point slave node.

For the specific process, reference is made to the description in (1) above, which is not repeated herein.

In an optional embodiment of the invention, the method further comprises: calculation formula A by clock synchronization precision _ts Calculating clock synchronization accuracy, wherein α represents an outer coincidence accuracy, the outer coincidence accuracy is 10-20ns when an external clock source reference is a GNSS clock or an atomic clock of a GNSS satellite, the outer coincidence accuracy is 1.5 μ s when the external clock source reference is a network clock, β represents an inner coincidence accuracy, the inner coincidence accuracy β is B n, B represents time synchronization accuracy of a gPTP protocol stack, n represents the transmission times of the gPTP protocol stack, γ represents a margin, γ is (α + β) B, and B represents a preset percentage value.

Specifically, the deviation between the atomic clock of the GNSS clock or the GNSS satellite and the Coordinated Universal Time (UTC) is generally 10 to 20ns, so when the external clock source reference is the GNSS clock or the atomic clock of the GNSS satellite, the external coincidence accuracy is 10 to 20ns, the 4G network timing accuracy is about 1.5 μ s, the 5G timing accuracy is higher than 4G, the maximum deviation of the external clock reference is 1.5 μ s, and when the external clock source reference is the network clock, the external coincidence accuracy is 1.5 μ s; the time synchronization precision B of the gPTP protocol stack is 30-50ns, even if the gPTP Grandmaster, gPTP Bridge and gPTP End Point are subjected to multiple accumulation calculation, the time synchronization precision B does not exceed 90-150 ns, the internal coincidence precision beta is B n, and n is 3 in the embodiment of the invention; considering the influence of link propagation loss, etc., it is generally considered that the margin of propagation loss, etc., is to amplify a preset percentage value on the basis of the fixed deviation (α + β), and in the embodiment of the present invention, the preset percentage value may be 30%, that is, γ is (α + β) × 30%, so that the overall clock synchronization accuracy a is obtained _ts ＝α+β+γ＝1.3(α+β)<10 mu s, namely the method can realize microsecond (mu s) level synchronization precision of the whole vehicle clock.

In an optional embodiment of the invention, the method further comprises:

1) acquiring a message which is sent by a target domain controller and carries a timestamp;

2) judging whether the delay of the message is overtime based on the timestamp;

specifically, a time difference is calculated according to a timestamp and the current clock time of the domain controller; if the time difference is larger than a preset threshold value, determining the delay overtime of the message; and if the time difference is not greater than the preset threshold value, determining that the delay of the message is not overtime.

3) If overtime, discarding the message;

4) if not, the message is used.

The method is established on the basis of the existing gPTP protocol stack technology, and a high-precision clock synchronization and frequency synchronization scheme which can be widely applied to an automatic driving automobile is designed; the problem of how to determine the external clock source reference under different scene working conditions is solved, and particularly the clock synchronization method under the scene that both a satellite and a network are unavailable is solved; the vehicle internal clock synchronization architecture of the cross-domain controller is realized, and all domain controllers, especially units and modules with requirements on real-time performance, can realize strict clock synchronization; in addition, the external coincidence precision and the internal coincidence precision are comprehensively considered, and a clock precision performance analysis method (clock synchronization precision calculation formula) of the automatic driving vehicle is provided for the link propagation loss and margin, and the clock synchronization can reach the micron-level synchronization precision.

Example two:

the embodiment of the invention also provides a clock and frequency synchronizing device for automatically driving the whole vehicle, which is mainly used for executing the clock and frequency synchronizing method for automatically driving the whole vehicle provided by the embodiment of the invention, and the clock and frequency synchronizing device for automatically driving the whole vehicle provided by the embodiment of the invention is specifically introduced below.

Fig. 4 is a schematic diagram of a clock and frequency synchronization device for an automatically driven vehicle according to an embodiment of the present invention, where the automatically driven vehicle includes: the intelligent network unit, the central control unit, the intelligent driving unit, the intelligent cockpit unit and the sub-function system all follow an ARM Cortex architecture, wherein an M core of the intelligent network unit deploys a gpptp Grandmaster node, an M core of the central control unit deploys a gPTP Grandmaster slave node and a gPTP Bridge master node, an M core and an R core of the intelligent driving unit both deploy a gpptp edge slave node and a gPTP edge master node, an a core of the intelligent driving unit deploys a gPTP edge slave node, an M core of the intelligent cockpit unit deploys a gPTP edge slave node and a gPTP edge master node, a sub-function system deploys a gPTP edge slave node, and referring to fig. 4, the device comprises: a determination unit 10 and an execution unit 20, wherein:

and the execution unit is used for executing clock and frequency synchronization among the intelligent networking unit, the central control unit, the intelligent driving unit, the intelligent cabin unit and the sub-function system by adopting a gPTP (gigabit time protocol) stack based on an external clock source reference.

In an embodiment of the present invention, a clock and frequency synchronization apparatus for automatically driving a whole vehicle is provided, where the automatically driving whole vehicle includes: the intelligent network unit, the central control unit, the intelligent driving unit, the intelligent cabin unit and the sub-function system all follow an ARM Cortex architecture, wherein an M core of the intelligent network unit deploys a gPTP Grandmaster master node, an M core of the central control unit deploys a gPTP Grandmaster slave node and a gPTP Bridge master node, an M core and an R core of the intelligent driving unit both deploy gPTP Bridge slave nodes and gPTP End Point master nodes, an A core of the intelligent driving unit deploys a gPTP End Point slave node, an M core of the intelligent cabin unit deploys a gPTP Bridge slave node and a gPTP End Point master node, and the sub-function system deploys a gPTP End Point slave node, the method comprises the following steps: determining an external clock source reference under different scene working conditions; and performing clock and frequency synchronization among the intelligent networking unit, the central control unit, the intelligent driving unit, the intelligent cabin unit and the sub-function system by adopting a gPTP protocol stack based on the external clock source reference. According to the description, the clock and frequency synchronization device for the automatic driving whole vehicle can realize the clock and frequency synchronization of the automatic driving whole vehicle, has high synchronization precision, and solves the technical problem that the clock and frequency synchronization of the automatic driving whole vehicle cannot be realized in the prior art.

Optionally, the determining unit is further configured to: when the number of GNSS satellites observed by a GNSS antenna of the automatic driving whole vehicle is not less than 4, a GNSS clock obtained by positioning and resolving of a GNSS receiver is used as an external clock source reference; when the number of GNSS satellites observed by a GNSS antenna of the automatic driving whole vehicle is less than 4, taking an atomic clock of any observed GNSS satellite as an external clock source reference; when the GNSS antenna of the automatic driving whole vehicle cannot observe any GNSS satellite, acquiring a network clock through a modem of the intelligent networking unit, and taking the network clock as an external clock source reference; when the GNSS antenna of the automatic driving whole vehicle cannot observe any GNSS satellite and network coverage does not exist in the area where the automatic driving whole vehicle is located, the external clock source reference is determined based on the clock when the signals of the GNSS satellite and the network signals are lost simultaneously.

Optionally, the determining unit is further configured to: taking a clock when the GNSS satellite signal and the network signal are lost simultaneously as an initial clock; calculating a current clock according to the initial clock, the oscillation frequency and the oscillation period of a crystal oscillator in the intelligent networking unit; and taking the current clock as an external clock source reference.

Optionally, the execution unit is further configured to: clock and frequency synchronization between an M core of an intelligent network connection unit and an M core of a central control unit is completed through receiving and transmitting clock synchronization messages between a gPTP Grandmaster node and a gPTP Grandmaster slave node, wherein the gPTP Grandmaster node is used for acquiring an external clock source reference; clock and frequency synchronization between M cores of a central control unit, clock and frequency synchronization between M cores of the central control unit and an intelligent driving unit, and clock and frequency synchronization between the M cores of the central control unit and an intelligent cabin unit are completed through clock synchronization message transceiving between a gPTP Bridge master node and a gPTP Bridge slave node; and completing the clock and frequency synchronization between the R core of the intelligent driving unit, the M core of the intelligent driving unit and the A core of the intelligent driving unit and the clock and frequency synchronization between the M core of the intelligent cabin unit and the sub-function system by receiving and transmitting clock synchronization messages between the gPTP End Point master node and the gPTP End Point slave node.

Optionally, the apparatus is further configured to: calculation formula A by clock synchronization precision _ts Calculating clock synchronization accuracy, wherein α represents an outer coincidence accuracy, the outer coincidence accuracy is 10-20ns when an external clock source reference is a GNSS clock or an atomic clock of a GNSS satellite, the outer coincidence accuracy is 1.5 μ s when the external clock source reference is a network clock, β represents an inner coincidence accuracy, the inner coincidence accuracy β is B n, B represents time synchronization accuracy of a gPTP protocol stack, n represents the transmission times of the gPTP protocol stack, γ represents a margin, γ is (α + β) B, and B represents a preset percentage value.

Optionally, the apparatus is further configured to: acquiring a message which is sent by a target domain controller and carries a timestamp; judging whether the delay of the message is overtime based on the timestamp; if overtime, discarding the message; if not, the message is used.

Optionally, the apparatus is further configured to: calculating a time difference according to the timestamp and the current clock time of the domain controller; if the time difference is larger than a preset threshold value, determining the delay overtime of the message; and if the time difference is not greater than the preset threshold value, determining that the delay of the message is not overtime.

The device provided by the embodiment of the present invention has the same implementation principle and technical effect as the method embodiments, and for the sake of brief description, reference may be made to the corresponding contents in the method embodiments without reference to the device embodiments.

As shown in fig. 5, an electronic device 600 provided in an embodiment of the present application includes: the system comprises a processor 601, a memory 602 and a bus, wherein the memory 602 stores machine readable instructions executable by the processor 601, when the electronic device runs, the processor 601 and the memory 602 communicate through the bus, and the processor 601 executes the machine readable instructions to execute the steps of the clock and frequency synchronization determination method of the automatic driving whole vehicle.

Specifically, the memory 602 and the processor 601 can be general-purpose memories and processors, and are not limited to specific ones, and the processor 601 can execute the synchronization determining method for the clock and the frequency of the autonomous driving vehicle when executing the computer program stored in the memory 602.

The processor 601 may be an integrated circuit chip having signal processing capabilities. In implementation, the steps of the above method may be performed by integrated logic circuits of hardware or instructions in the form of software in the processor 601. The Processor 601 may be a general-purpose Processor, and includes a Central Processing Unit (CPU), a Network Processor (NP), and the like; the device can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components. The various methods, steps, and logic blocks disclosed in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in the memory 602, and the processor 601 reads the information in the memory 602 and completes the steps of the method in combination with the hardware thereof.

Corresponding to the method for synchronously determining the clock and the frequency of the whole automatic driving vehicle, the embodiment of the application also provides a computer readable storage medium, wherein a machine executable instruction is stored in the computer readable storage medium, and when the computer executable instruction is called and operated by a processor, the computer executable instruction causes the processor to operate the steps of the method for synchronously determining the clock and the frequency of the whole automatic driving vehicle.

The device for determining the clock and the frequency of the automatic driving whole vehicle provided by the embodiment of the application can be specific hardware on equipment or software or firmware installed on the equipment and the like. The device provided by the embodiment of the present application has the same implementation principle and technical effect as the foregoing method embodiments, and for the sake of brief description, reference may be made to the corresponding contents in the foregoing method embodiments where no part of the device embodiments is mentioned. It can be clearly understood by those skilled in the art that, for convenience and simplicity of description, the specific working processes of the system, the apparatus and the unit described above may all refer to the corresponding processes in the method embodiments, and are not described herein again.

In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units is only one logical division, and there may be other divisions when actually implemented, and for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection of devices or units through some communication interfaces, and may be in an electrical, mechanical or other form.

For another example, the flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments provided in the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing an electronic device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the vehicle marking method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined or explained in subsequent figures, and moreover, the terms "first," "second," "third," etc. are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.

Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present application, and are used for illustrating the technical solutions of the present application, but not limiting the same, and the scope of the present application is not limited thereto, and although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: those skilled in the art can still make modifications or changes to the embodiments described in the foregoing embodiments, or make equivalent substitutions for some features, within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the scope of the embodiments of the present application. Are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A clock and frequency synchronization method for automatically driving a whole vehicle is characterized by comprising the following steps: the intelligent driving system comprises an intelligent networking unit, a central control unit, an intelligent driving unit, an intelligent cabin unit and a sub-function system, wherein the intelligent networking unit, the central control unit, the intelligent driving unit and the intelligent cabin unit all follow an ARM Cortex architecture, a gPTP Grandmaster master node is deployed in an M core of the intelligent networking unit, a gPTP Grandmaster slave node and a gPTP Bridge master node are deployed in an M core of the central control unit, a gPTP Bridge slave node and a gPTP End master node are deployed in an M core and an R core of the intelligent driving unit, a gPTP End Point slave node is deployed in an A core of the intelligent driving unit, a gPTP Bridge slave node and a gPTP End Point are deployed in an M core of the intelligent cabin unit, the sub-function system is a gPTP End slave node, and the method comprises the following steps:

2. The method of claim 1, wherein determining an external clock source reference under different scene conditions comprises:

3. The method of claim 2, wherein determining the external clock source reference based on a clock when signals of the GNSS satellites and network signals are simultaneously lost comprises:

and taking the current clock as the external clock source reference.

4. The method of claim 1, wherein performing clock and frequency synchronization between the intelligent networking unit, the central control unit, the intelligent driving unit, the intelligent cabin unit, and the sub-functional system using a gPTP protocol stack based on the external clock source reference comprises:

5. The method of claim 1, further comprising:

calculation formula A by clock synchronization precision _ts Calculating clock synchronization accuracy, wherein α represents an outer coincidence accuracy, the outer coincidence accuracy is 10-20ns when the external clock source reference is a GNSS clock or an atomic clock of a GNSS satellite, the outer coincidence accuracy is 1.5 μ s when the external clock source reference is a network clock, β represents an inner coincidence accuracy, the inner coincidence accuracy β is B n, B represents time synchronization accuracy of a gPTP protocol stack, n represents the transmission number of the gPTP protocol stack, γ represents a margin, γ (α + β) B, and B represents a preset hundred, andand (4) dividing the ratio.

6. The method of claim 1, further comprising:

if overtime, discarding the message;

and if not, using the message.

7. The method of claim 6, wherein determining whether the delay of the message is time out based on the timestamp comprises:

8. The utility model provides a synchronizer of clock and frequency of automatic drive whole car which characterized in that, the automatic drive whole car includes: the intelligent driving device comprises an intelligent networking unit, a central control unit, an intelligent driving unit, an intelligent cabin unit and a sub-function system, wherein the intelligent networking unit, the central control unit, the intelligent driving unit and the intelligent cabin unit all follow an ARM Cortex architecture, a gPTP Grandmaster master node is deployed in an M core of the intelligent networking unit, a gPTP Grandmaster slave node and a gPTP Bridge master node are deployed in an M core of the central control unit, a gPTP Bridge slave node and a gPTP End master node are deployed in an M core and an R core of the intelligent driving unit, a gPTP End Point slave node is deployed in an A core of the intelligent driving unit, a gPTP Bridge slave node and a gPTP End Point are deployed in an M core of the intelligent cabin unit, the sub-function system gPTP End slave node is deployed in the sub-function system, and the device comprises:

9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the steps of the method of any of the preceding claims 1 to 7 are implemented when the computer program is executed by the processor.

10. A computer readable storage medium having stored thereon machine executable instructions which, when invoked and executed by a processor, cause the processor to perform the method of any of claims 1 to 7.