CN112671497A - Time synchronization method and device and electronic equipment - Google Patents
Time synchronization method and device and electronic equipment Download PDFInfo
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Abstract
The invention provides a time synchronization method, a time synchronization device and electronic equipment. The method is applied to an automatic driving system of a vehicle, wherein the automatic driving system comprises a combined navigation system, a time synchronization device, a domain controller and at least one laser radar; the method comprises the following steps: the combined navigation system receives a satellite time signal; the integrated navigation system transmits a timestamp signal and a second pulse signal to a time synchronization device based on the satellite time signal; the time synchronization device simultaneously sends the timestamp signal and the second pulse signal to the laser radar and the domain controller; the laser radar and the domain controller determine a system time of the laser radar and the domain controller based on the timestamp signal and the second pulse signal. In this manner, a time stamp based on a uniform time axis can be given to each module in the automatic driving system of the vehicle, and high accuracy and high stability are achieved.
Description
Technical Field
The present invention relates to the field of digital information transmission technologies, and in particular, to a time synchronization method, a time synchronization apparatus, and an electronic device.
Background
In recent years, the automatic driving technology becomes the most active topic in the world, and the important link of the technology is to acquire the information of the surrounding environment of the vehicle through various perception technologies, and make a corresponding driving decision based on the fusion result of the perception information so as to control the vehicle to run. Due to differences of data preprocessing delay, data transmission paths and the like of various sensing technologies, delay needed by reaching a fusion module of a domain controller by various environment sensing information is inconsistent. In order to restore the surrounding environment information more truly, the environment information collected at the same time needs to be fused. It is therefore necessary to assign a time stamp based on a uniform time axis to various perceptual information and data processing units.
In the prior art, the accuracy and the stability of timestamps given to various sensing information and a data processing unit by a vehicle driving system are low.
Disclosure of Invention
In view of the above, the present invention provides a time synchronization method, a time synchronization apparatus, and an electronic device, so as to improve accuracy and stability.
In a first aspect, an embodiment of the present invention provides a time synchronization method, which is applied to an automatic driving system of a vehicle, where the automatic driving system includes a combined navigation system, a time synchronization device, a domain controller, and at least one laser radar; the method comprises the following steps: the combined navigation system receives a satellite time signal; the integrated navigation system transmits a timestamp signal and a second pulse signal to a time synchronization device based on the satellite time signal; the time synchronization device simultaneously sends the timestamp signal and the second pulse signal to the laser radar and the domain controller; the laser radar and the domain controller determine a system time of the laser radar and the domain controller based on the timestamp signal and the second pulse signal.
In a preferred embodiment of the present invention, the step of sending the timestamp signal and the pulse-per-second signal to the time synchronizer based on the satellite time signal by the integrated navigation system includes: the combined navigation system converts the satellite time signal into a timestamp signal; the combined navigation system sends a timestamp signal to the time synchronization device at a preset first interval; and the combined navigation system sends a pulse per second signal to the time synchronization device at a preset second interval.
In a preferred embodiment of the present invention, the timestamp signal is an RS232 signal, and the pulse-per-second signal is a transistor-transistor logic TTL signal.
In a preferred embodiment of the present invention, the step of sending the timestamp signal and the pulse-per-second signal to the laser radar and the domain controller by the time synchronizer includes: the time synchronizer converts an RS232 signal into a first TTL signal through an RS232 transceiver, converts the first TTL signal into a first RS485 signal through a phase inverter and an RS485 transceiver, expands the first RS485 signal into a plurality of paths of first TTL signals through the RS485 transceiver expanded on an RS485 bus, converts the plurality of paths of first TTL signals into a plurality of paths of RS232 signals through the phase inverter and the RS232 transceiver, and simultaneously sends the plurality of paths of RS232 signals to the laser radar and the domain controller; and the time synchronization device converts the second TTL signal into a second RS485 signal, expands the second RS485 signal into a plurality of paths of second TTL signals through the RS485 transceiver expanded on the RS485 bus, and simultaneously sends the plurality of paths of second TTL signals to the laser radar and the domain controller.
In a preferred embodiment of the present invention, the step of determining the system time of the laser radar and the domain controller based on the timestamp signal and the pulse per second signal includes: the laser radar and the domain controller convert the first RS485 signal into an RS232 signal; the laser radar and the domain controller convert the second RS485 signal into a TTL signal; the lidar and the domain controller determine system times of the lidar and the domain controller based on the RS232 signal and the TTL signal.
In a preferred embodiment of the present invention, the step of determining the system time of the laser radar and the domain controller based on the timestamp signal and the pulse per second signal includes: triggering and acquiring a timestamp signal by the laser radar and the domain controller in a second pulse signal rising edge triggering mode; and the laser radar and the domain controller determine the system time of the laser radar and the domain controller according to the acquired timestamp signals.
In a preferred embodiment of the present invention, the automatic driving system further includes a millimeter wave radar and a visual perception module.
In a second aspect, an embodiment of the present invention further provides a time synchronization apparatus, which is applied to an automatic driving system of a vehicle, where the automatic driving system includes a combined navigation system, the time synchronization apparatus, a domain controller, and at least one laser radar; the device comprises: the signal receiving module is used for receiving satellite time signals by the integrated navigation system; the signal sending module is used for sending a timestamp signal and a second pulse signal to the time synchronization device by the integrated navigation system based on the satellite time signal; the signal synchronization module is used for simultaneously sending the timestamp signal and the second pulse signal to the laser radar and the domain controller by the time synchronization device; and the system time determining module is used for determining the system time of the laser radar and the domain controller based on the timestamp signal and the second pulse signal.
In a third aspect, an embodiment of the present invention further provides an electronic device, which includes a processor and a memory, where the memory stores computer-executable instructions that can be executed by the processor, and the processor executes the computer-executable instructions to implement the steps of the time synchronization method described above.
In a fourth aspect, embodiments of the present invention also provide a computer-readable storage medium storing computer-executable instructions that, when invoked and executed by a processor, cause the processor to implement the steps of the time synchronization method described above.
The embodiment of the invention has the following beneficial effects:
according to the time synchronization method, the time synchronization device and the electronic equipment, the integrated navigation system sends the timestamp signal and the second pulse signal to the time synchronization device according to the received satellite time signal, the time synchronization device sends the timestamp signal and the second pulse signal to the laser radar and the domain controller at the same time, and the laser radar and the domain controller determine respective system time based on the timestamp signal and the second pulse signal. In this manner, a time stamp based on a uniform time axis can be given to each module in the automatic driving system of the vehicle, and high accuracy and high stability are achieved.
Additional features and advantages of the disclosure will be set forth in the description which follows, or in part may be learned by the practice of the above-described techniques of the disclosure, or may be learned by practice of the disclosure.
In order to make the aforementioned objects, features and advantages of the present disclosure more comprehensible, preferred embodiments accompanied with figures are described in detail below.
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 time synchronization method according to an embodiment of the present invention;
FIG. 2 is a flow chart of another time synchronization method according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of an autopilot system according to an embodiment of the invention;
fig. 4 is a schematic diagram of a hardware architecture of a time synchronization apparatus according to an embodiment of the present invention;
fig. 5 is a schematic diagram of an RS232 signal synchronization circuit according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a TTS signal synchronization circuit according to an embodiment of the present invention;
FIG. 7 is a timing diagram illustrating a time synchronization method according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of a time synchronization apparatus according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent 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, the accuracy of timestamps given to various sensing information and a data processing unit by a vehicle driving system is not high, and the stability is poor. Based on this, the embodiment of the invention provides a time synchronization method, a time synchronization device and electronic equipment, and particularly relates to a time synchronization method and a time synchronization device for a multi-laser radar and a domain controller of an automatic driving system.
To facilitate understanding of the embodiment, a detailed description will be given to a time synchronization method disclosed in the embodiment of the present invention.
The first embodiment is as follows:
the embodiment of the invention provides a time synchronization method, which is applied to an automatic driving system of a vehicle.
Based on the above description, refer to the flowchart of a time synchronization method shown in fig. 1, the time synchronization method includes the following steps:
step S102, the integrated navigation system receives the satellite time signal.
The method provided by the embodiment is applied to an automatic driving system of a vehicle, and the automatic driving system can realize time synchronization according to the method provided by the embodiment. In order to restore the surrounding environment information more truly, the environment information collected at the same time needs to be fused, and a timestamp based on a uniform time axis needs to be given to various sensing information and data processing units, which means that the significance of realizing time synchronization between a plurality of laser radars and a domain controller in an automatic driving system is required in the invention.
A receiver in an existing vehicle-mounted integrated Navigation System can acquire high-precision UTC (Coordinated Universal Time) Time data of satellites such as a GPS (Global Positioning System), a BDS (BeiDou Navigation Satellite System), and a second pulse signal. The time service UTC time of the positioning satellite to the receiver of the vehicle-end integrated navigation system can be used as the uniform reference time for time synchronization of the automatic driving system, and the pulse per second signal can be used for periodically calibrating the time of a sensor or a domain controller for receiving the UTC time. Therefore, a time synchronization device is needed to transmit the UTC time and pulse per second signals received by the receiver in the integrated navigation system to a plurality of sensors or controllers in the autopilot system, which need to receive the UTC time and synchronize the UTC time and the pulse per second signals, and the transmitted UTC clock signals and pulse per second signals are required to have high accuracy and high stability.
The satellite time signal is a time signal transmitted by a satellite, and the satellite in this embodiment may be a GPS satellite or a BDS satellite.
In step S104, the integrated navigation system transmits the time stamp signal and the second pulse signal to the time synchronizer based on the satellite time signal.
After receiving the satellite time signal, the integrated navigation system may analyze the satellite time signal to obtain a timestamp signal, and the timestamp signal in this embodiment may be a UTC timestamp. After obtaining the time stamp signal, the integrated navigation system may send the time stamp signal and the pulse-per-second signal to a time synchronizer in the autonomous driving system.
And step S106, the time synchronization device simultaneously sends the timestamp signal and the second pulse signal to the laser radar and the domain controller.
The autopilot system in this embodiment includes a domain controller and at least one lidar. The domain controller is mainly used for automatic driving, and the laser radar is mainly used for sensing obstacles around the vehicle. All the laser radars and the domain controller need to perform time synchronization, and in this embodiment, the automatic driving system includes the domain controller and 3 laser radars as an example.
In addition, the automatic driving system in the embodiment may further include a millimeter wave radar and a visual perception module. The millimeter wave radar is used for scanning millimeter-scale radar, and the visual perception module is used for visually perceiving vehicles.
In order to synchronize all the laser radars and the domain controller in time, the time synchronization device may divide the timestamp signal and the pulse per second signal into four parts, and transmit the four parts of the timestamp signal and the pulse per second signal to the laser radars and the domain controller at the same time.
And S108, the laser radar and the domain controller determine the system time of the laser radar and the domain controller based on the timestamp signal and the second pulse signal.
The lidar and the domain controller may determine respective system times based on the received timestamp signal and the second pulse signal. Because the time synchronizer sends the four timestamp signals and the second pulse signals to the laser radar and the domain controller simultaneously, and the laser radar and the domain controller receive the timestamp signals and the second pulse signals simultaneously, the laser radar and the domain controller can have the same system time, and the time synchronization is realized.
According to the time synchronization method, the combined navigation system sends the timestamp signal and the second pulse signal to the time synchronization device according to the received satellite time signal, the time synchronization device sends the timestamp signal and the second pulse signal to the laser radar and the domain controller at the same time, and the laser radar and the domain controller determine respective system time based on the timestamp signal and the second pulse signal. In this manner, a time stamp based on a uniform time axis can be given to each module in the automatic driving system of the vehicle, and high accuracy and high stability are achieved.
Example two:
the embodiment of the invention also provides another time synchronization method; the method is realized on the basis of the method of the embodiment; the method mainly describes a specific implementation mode of sending a timestamp signal and a second pulse signal to a time synchronization device by a combined navigation system based on a satellite time signal. Another time synchronization method, as shown in fig. 2, includes the following steps:
in step S202, the integrated navigation system receives a satellite time signal.
The invention aims to provide a time synchronization method and a time synchronization device for multiple laser radars and a domain controller of an automatic driving system.
The embodiment of the invention provides a multi-laser radar and domain controller time synchronization method and device for an automatic driving system. Referring to the schematic diagram of an autopilot system shown in fig. 3, the autopilot system of the present embodiment includes a combination navigation system, a time synchronizer, an autopilot domain controller, and three lidar lasers.
And step S204, the integrated navigation system converts the satellite time signal into a time stamp signal.
As shown in fig. 3, the time synchronizer includes a PPS (Pulse Per Second) signal synchronization circuit and an RS232 signal synchronization circuit, wherein the integrated navigation system receives the satellite time signal and can convert the satellite time signal into a time stamp signal. The timestamp signal in this embodiment may be an RS232 signal, and the pulse-per-second signal may be a TTL (Transistor-Transistor Logic) signal.
In step S206, the integrated navigation system sends a timestamp signal to the time synchronizer at a preset first interval.
After the integrated navigation system converts the satellite time signal into the time stamp signal, the integrated navigation system may send the time stamp signal out every whole second in a data format of a gprs mc (recommended positioning information), that is, the first interval is 1 second. The GPRMC data format is as follows:
and GPRMC,014600.00, a,2237.496474, N,11356.089515, E,0.0,225.5,310518,2.3, W, a × 23. Wherein: 014600.00 are UTC time stamps.
In step S208, the integrated navigation system sends the pulse-per-second signal to the time synchronizer at a preset second interval.
The combined navigation system may signal out a second pulse in the form of a 5V TTL level every second, i.e., a second interval of 1 second.
And step S210, the time synchronization device simultaneously sends the timestamp signal and the second pulse signal to the laser radar and the domain controller.
As shown in fig. 3, the time synchronizer may divide the pulse-per-second signal and the RS232 signal (including the UTC timestamp) into four parts, and transmit one time stamp signal and one pulse-per-second signal to 3 laser radars and domain controllers, respectively.
Specifically, the time synchronization apparatus may transmit the RS232 signal and the TTL signal by: the time synchronizer converts an RS232 signal into a first TTL signal through an RS232 transceiver, converts the first TTL signal into a first RS485 signal through a phase inverter and an RS485 transceiver, expands the first RS485 signal into a plurality of paths of first TTL signals through the RS485 transceiver expanded on an RS485 bus, converts the plurality of paths of first TTL signals into a plurality of paths of RS232 signals through the phase inverter and the RS232 transceiver, and simultaneously sends the plurality of paths of RS232 signals to the laser radar and the domain controller; and the time synchronization device converts the second TTL signal into a second RS485 signal, expands the second RS485 signal into a plurality of paths of second TTL signals through the RS485 transceiver expanded on the RS485 bus, and simultaneously sends the plurality of paths of second TTL signals to the laser radar and the domain controller.
Referring to fig. 4, a schematic diagram of a hardware architecture of a time synchronization apparatus mainly includes an RS232 signal synchronization circuit, a TTL signal synchronization circuit, and a 12V-5V DC/DC module of a power supply part of the module.
The design scheme of the RS232 signal synchronization circuit is described as follows: firstly, the basic theory of RS232 signal synchronization is to convert one path of RS232 signals into one path of RS485 signals, the RS485 signals are a bus transmission mode, a plurality of RS485 data receiving nodes can be hung on a bus to simultaneously receive the converted signals, then each RS485 receiving node converts the RS485 signals into the RS232 signals, and therefore the expansion of the RS232 signals is achieved, and as the signal conversion of each step is in ns level, the conversion delay of a basic logic circuit is in ns level, so that the time synchronization delay between the input and output paths of RS232 signals can be guaranteed to be within 1 us.
Referring to the schematic diagram of an RS232 signal synchronization circuit shown in fig. 5, a received RS232 signal is converted into a TTL level signal through an RS232 transceiver MAX232 chip, and then is converted into a path of RS485 bus signal through a hexagonal inverter 74HCT04 chip and an RS485 transceiver MAX485 chip, wherein the hexagonal inverter 74HCT04 chip plays a role in transmitting the TTL level and can also realize the enabling and transceiving modes of automatically configuring the MAX485 chip, that is, the high level state of the input TTL level is synchronized with the function mode of outputting the RS485 signal by receiving the TTL signal through the MAX 485. The MAX485 supports 32 RS485 nodes at most, so 4 RS485 transceiver MAX485 chips are mounted on an RS485 bus, RS485 signals are converted into 4 paths of TTL level signals, then each path of TTL level signals are transmitted through a hexagonal phase inverter 74HCT04 chip, and the enabling and receiving modes of the MAX485 chips are automatically configured, namely the RS485 signals received on the RS485 bus are synchronous with the RS485 signals received by the MAX485 bus and the TTL 485 high level function mode is output. Finally, the TTL signals output by the idea enter two RS232 transceiver MAX232 chips (each chip has two RS232 channels), and are converted into RS232 signals to be output.
The design scheme of the TTL signal synchronous circuit is described as follows: firstly, the basic theory of PPS signal synchronization is to convert a path of TTL signals into a path of RS485 signals, the RS485 signals are a bus transmission mode, a plurality of RS485 data receiving nodes can be hung on a bus to receive the converted signal at the same time, then each RS485 receiving node converts the RS485 signals into the TTL signals, and therefore the extension of the RS232 signals is achieved, and since the signal conversion of each step is that the conversion delay of a basic logic circuit is in ns level, the time synchronization delay between the input and output paths of TTL signals can be guaranteed to be within 1 us.
Referring to the schematic diagram of a TTS signal synchronization circuit shown in fig. 6, first, a received TTL signal passes through an isolated dc converter ADUM5402 chip to transfer a TTL level signal with low delay, and can play a role of circuit isolation protection, and then the TTL signal is converted into a path of RS485 bus signal through a hexagonal inverter 74HCT04 chip and an RS485 transceiver MAX485 chip, wherein the hexagonal inverter 74HCT04 chip can also realize the enabling and transceiving modes of automatically configuring the MAX485 chip while playing a role of transferring the TTL level, that is, the high level state of the input TTL level is synchronized with the function mode of outputting the RS485 signal by receiving the TTL signal at MAX 485. The MAX485 supports 32 RS485 nodes at most, so 4 RS485 transceiver MAX485 chips are mounted on an RS485 bus, RS485 signals are converted into 4 paths of TTL level signals, then each path of TTL level signals are transmitted through a hexagonal phase inverter 74HCT04 chip, and the enabling and receiving modes of the MAX485 chips are automatically configured, namely the RS485 signals received on the RS485 bus are synchronous with the RS485 signals received by the MAX485 bus and the TTL 485 high level function mode is output. And finally, the TTL signals output by the four paths enter four isolated direct current converters ADUM5402 chips respectively, and are converted into required PPS signals to be output.
In step S212, the laser radar and the domain controller determine the system time of the laser radar and the domain controller based on the timestamp signal and the second pulse signal.
The laser radar in the embodiment is mainly used for sensing surrounding obstacle information, and the domain controller is mainly used for processing external sensing information, deciding and planning the behavior and driving path of the vehicle and playing a role in controlling the vehicle through the actuator. The laser radar and the domain controller can trigger and acquire the timestamp signals in a second pulse signal rising edge triggering mode; and the laser radar and the domain controller determine the system time of the laser radar and the domain controller according to the acquired timestamp signals.
Specifically, three laser radars and one automatic driving domain controller trigger and acquire RS232 data sent by a time synchronization device in a pulse per second (PPS MC) rising edge triggering mode, acquire a GPRMC data frame, analyze and extract a UTC timestamp, and use the UTC timestamp as respective system time, so that time synchronization between the laser radars and the domain controller is realized.
The lidar and the domain controller may determine respective system times based on respective timestamp signals and pulse-per-second signals, respectively, which may be performed by: the laser radar and the domain controller convert the first RS485 signal into an RS232 signal; the laser radar and the domain controller convert the second RS485 signal into a TTL signal; the lidar and the domain controller determine system times of the lidar and the domain controller based on the RS232 signal and the TTL signal.
Referring to fig. 7, a timing diagram of a time synchronization method according to the present invention is shown, in which a timing chart of a data receiving end receiving a PPS signal and GPRMC data is shown in fig. 7. Because the bit length of the GPRMC data including the UTC timestamp is long (about 700 bits), and the CPU calculation delay and the transmission delay need to be considered in the transmitting and receiving processes of the transmitting end and the receiving end, the PPS signal and the GPRMC signal reach the MCU of the receiving end first. When a digital input interface of the MCU receives a rising edge of a PPS signal corresponding to the (N + 1) th second, an interrupt program is triggered to acquire synchronization time, and at the moment, GPMRC data corresponding to the Nth second is still stored in the RS232 data receiving buffer, so that a UTC time stamp in the GPMRC data corresponding to the Nth second needs to be extracted, and 1 second is added, namely the system synchronization time stamp of the receiving end at the moment.
In addition, the 12V-to-5V DC/DC module can adopt an IAGCH chip, needs 12V power supply input and provides 5V power supply output for the whole equipment.
The embodiment of the invention provides the method, and discloses a time synchronization method between a plurality of laser radars and a domain controller of an automatic driving system, wherein the automatic driving system comprises a combined navigation system, the automatic driving domain controller and three laser radars, the automatic driving system also comprises a time synchronization device, the time synchronization device comprises a PPS signal synchronization part and a UTC timestamp signal synchronization part, and the time synchronization method comprises the following steps: step one, a combined navigation system receives satellite time signals and converts the satellite time signals into UTC timestamps, the UTC timestamps are sent out once every whole second, and second pulse signals (the rising edge of the pulse signals is the time of the whole second) are sent out once every whole second; dividing the pulse per second signal and the UTC timestamp signal into four through a time synchronization device; and step three, triggering the UTC time stamp sent by the time synchronization device by the three laser radars and one automatic driving domain controller in a manner of triggering the rising edge of the pulse per second signal, and taking the UTC time stamp as respective system synchronization time, thereby realizing the time synchronization between the laser radars and the domain controller.
Example three:
corresponding to the method embodiment, the embodiment of the invention provides a time synchronization device, which is applied to an automatic driving system of a vehicle, wherein the automatic driving system comprises a combined navigation system, the time synchronization device, a domain controller and at least one laser radar; fig. 8 is a schematic structural diagram of a time synchronizer, which includes:
a signal receiving module 81, configured to receive a satellite time signal by using the integrated navigation system;
a signal transmitting module 82, configured to transmit a timestamp signal and a pulse per second signal to the time synchronization apparatus based on the satellite time signal by the integrated navigation system;
the signal synchronization module 83 is used for sending the timestamp signal and the second pulse signal to the laser radar and the domain controller simultaneously by the time synchronization device;
and a system time determination module 84 for the lidar and the domain controller to determine a system time of the lidar and the domain controller based on the timestamp signal and the second pulse signal.
According to the time synchronization device, the combined navigation system sends the timestamp signal and the second pulse signal to the time synchronization device according to the received satellite time signal, the time synchronization device sends the timestamp signal and the second pulse signal to the laser radar and the domain controller at the same time, and the laser radar and the domain controller determine respective system time based on the timestamp signal and the second pulse signal. In this manner, a time stamp based on a uniform time axis can be given to each module in the automatic driving system of the vehicle, and high accuracy and high stability are achieved.
The signal sending module is used for converting the satellite time signal into a timestamp signal by the integrated navigation system; the combined navigation system sends a timestamp signal to the time synchronization device at a preset first interval; and the combined navigation system sends a pulse per second signal to the time synchronization device at a preset second interval.
The timestamp signal is an RS232 signal, and the pulse per second signal is a transistor-transistor logic (TTL) signal.
The signal synchronization module is used for converting the RS232 signal into a first RS485 signal by the time synchronization device and simultaneously sending the first RS485 signal to the laser radar and the domain controller; and the time synchronization device converts the TTL signal into a second RS485 signal and simultaneously sends the second RS485 signal to the laser radar and the domain controller.
The system time determining module is used for converting the first RS485 signal into an RS232 signal by the laser radar and the domain controller; the laser radar and the domain controller convert the second RS485 signal into a TTL signal; the lidar and the domain controller determine system times of the lidar and the domain controller based on the RS232 signal and the TTL signal.
The system time determining module is used for triggering and acquiring a timestamp signal by the laser radar and the domain controller in a second pulse signal rising edge triggering mode; and the laser radar and the domain controller determine the system time of the laser radar and the domain controller according to the acquired timestamp signals.
The automatic driving system further comprises a millimeter wave radar and a visual perception module.
The time synchronization device provided by the embodiment of the invention has the same technical characteristics as the time synchronization method provided by the embodiment, so that the same technical problems can be solved, and the same technical effects can be achieved.
Example four:
the embodiment of the invention also provides electronic equipment, which is used for operating the time synchronization method; referring to fig. 9, a schematic structural diagram of an electronic device includes a memory 100 and a processor 101, where the memory 100 is used for storing one or more computer instructions, and the one or more computer instructions are executed by the processor 101 to implement the time synchronization method.
Further, the electronic device shown in fig. 9 further includes a bus 102 and a communication interface 103, and the processor 101, the communication interface 103, and the memory 100 are connected through the bus 102.
The Memory 100 may include a high-speed Random Access Memory (RAM) and may further include a non-volatile Memory (non-volatile Memory), such as at least one disk Memory. The communication connection between the network element of the system and at least one other network element is realized through at least one communication interface 103 (which may be wired or wireless), and the internet, a wide area network, a local network, a metropolitan area network, and the like can be used. The bus 102 may be an ISA bus, PCI bus, EISA bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one double-headed arrow is shown in FIG. 9, but this does not indicate only one bus or one type of bus.
The processor 101 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 101. The Processor 101 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 device, a discrete Gate or transistor logic device, or a discrete hardware component. The various methods, steps and logic blocks disclosed in the embodiments of the present invention 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 invention 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 100, and the processor 101 reads the information in the memory 100, and completes the steps of the method of the foregoing embodiment in combination with the hardware thereof.
The embodiment of the present invention further provides a computer-readable storage medium, where the computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are called and executed by a processor, the computer-executable instructions cause the processor to implement the time synchronization method.
The computer program product of the time synchronization method and apparatus provided in the embodiments of the present invention includes a computer-readable storage medium storing a program code, where instructions included in the program code may be used to execute the method in the foregoing method embodiments, and specific implementation may refer to the method embodiments, and details are not described here.
It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of the apparatus and/or the electronic device described above may refer to corresponding processes in the foregoing method embodiments, and are not described herein again.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A time synchronization method is characterized in that the method is applied to an automatic driving system of a vehicle, wherein the automatic driving system comprises a combined navigation system, a time synchronization device, a domain controller and at least one laser radar; the method comprises the following steps:
the integrated navigation system receives a satellite time signal;
the integrated navigation system transmits a time stamp signal and a second pulse signal to the time synchronization device based on the satellite time signal;
the time synchronization device simultaneously transmits the timestamp signal and the pulse per second signal to the laser radar and the domain controller;
the lidar and the domain controller determine system times of the lidar and the domain controller based on the timestamp signal and the pulse per second signal.
2. The method of claim 1, wherein the step of the integrated navigation system transmitting a time stamp signal and a pulse per second signal to the time synchronization device based on the satellite time signal comprises:
the combined navigation system converts the satellite time signal into a timestamp signal;
the combined navigation system sends the timestamp signals to the time synchronization device at preset first intervals;
and the combined navigation system sends a pulse per second signal to the time synchronization device at a preset second interval.
3. The method of claim 2, wherein the timestamp signal is an RS232 signal and the pulse-per-second signal is a transistor-transistor logic, TTL, signal.
4. The method of claim 3, wherein the step of the time synchronizer transmitting the time stamp signal and the pulse per second signal simultaneously to the lidar and the domain controller comprises:
the time synchronizer converts the RS232 signals into first TTL signals through an RS232 transceiver, converts the first TTL signals into first RS485 signals through a phase inverter and an RS485 transceiver, expands the first RS485 signals into multiple paths of first TTL signals through the RS485 transceiver expanded on an RS485 bus, converts the multiple paths of first TTL signals into multiple paths of RS232 signals through the phase inverter and the RS232 transceiver, and simultaneously sends the multiple paths of RS232 signals to the laser radar and the domain controller;
and the time synchronizer converts the second TTL signal into a second RS485 signal, expands the second RS485 signal into a plurality of paths of second TTL signals through an RS485 transceiver expanded on an RS485 bus, and simultaneously sends the plurality of paths of second TTL signals to the laser radar and the domain controller.
5. The method of claim 4, wherein the step of the lidar and the domain controller determining a system time of the lidar and the domain controller based on the timestamp signal and the pulse-per-second signal comprises:
the laser radar and the domain controller convert the first RS485 signal into the RS232 signal;
the laser radar and the domain controller convert the second RS485 signal into the TTL signal;
the lidar and the domain controller determine system times of the lidar and the domain controller based on the RS232 signal and the TTL signal.
6. The method of claim 1, wherein the step of the lidar and the domain controller determining a system time of the lidar and the domain controller based on the timestamp signal and the pulse-per-second signal comprises:
the laser radar and the domain controller trigger and acquire the timestamp signals in a manner of triggering the rising edge of the pulse per second signal;
and the laser radar and the domain controller determine the system time of the laser radar and the domain controller according to the acquired timestamp signals.
7. The method of claim 1, wherein the autopilot system further comprises a millimeter wave radar and a visual perception module.
8. A time synchronizer, characterized in that, is applied to an automatic driving system of a vehicle, the automatic driving system comprises a combined navigation system, the time synchronizer, a domain controller and at least one laser radar; the device comprises:
the signal receiving module is used for receiving the satellite time signal by the integrated navigation system;
a signal transmission module, configured to transmit a timestamp signal and a pulse-per-second signal to the time synchronization apparatus by the integrated navigation system based on the satellite time signal;
the signal synchronization module is used for the time synchronization device to simultaneously send the timestamp signal and the pulse per second signal to the laser radar and the domain controller;
a system time determination module for the lidar and the domain controller to determine a system time of the lidar and the domain controller based on the timestamp signal and the pulse per second signal.
9. An electronic device comprising a processor and a memory, the memory storing computer-executable instructions executable by the processor, the processor executing the computer-executable instructions to perform the steps of the time synchronization method of any one of claims 1-7.
10. A computer-readable storage medium having stored thereon computer-executable instructions that, when invoked and executed by a processor, cause the processor to perform the steps of the time synchronization method of any of claims 1-7.
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