35results about How to "High precision time synchronization" patented technology

The invention discloses a time synchronization method of a master-slave structure multi-node network. Two clock synchronization mechanisms of a response type mechanism and a broadcast type mechanism are designed aiming at the condition that nodes of the network are physically connected through wires, and the communication between the nodes is performed through RS485, RS422, RS232, CAN bus modes. Accurate sending and receiving times of each message can be obtained through FPGA clock sampling. The transmission average delay and the master-slave clock offset are calculated through a response type synchronization mode, and the time precision is compensated and the time synchronization with the nanosecond grade high precision is reached. The time synchronization with the higher precision can be reached when the channel transmission time delay is ignored through a broadcast type synchronization mode.

The invention relates to a symmetrical noncoherent distance measurement / time synchronism system of a cluster link two-way asynchronous communication channel, belonging to the autonomous technical field of aviation data links, radio navigation and aircrafts. By the invention, a symmetrical noncoherent distance measurement / time synchronism method and a system framework can be realized on a DSP (Digital Signal Processor) of a circuit board and an FPGA (Field Programmable Gate Array). Based on the two-way asynchronous communication link between cluster link member nodes, the noncoherent distance measurement / time synchronism system provides a noncoherent spread spectrum distance measurement principle of a two-way asynchronous communication frame under a comprehensive channel system, constructs a noncoherent spread spectrum distance measurement algorithm structure of the air fleet link two-way asynchronous communication frame in a uniform form by adopting a communication frame based on CCSDS Proximity-1 version-3 and provides two algorithms of base line measurement and time synchronism measurement control: an interprocessor time synchronism recursive algorithm and a Doppler integral compensation algorithm. The invention overcomes the defects of the traditional coherent transferring distance measurement and the two-way synchronous noncoherent distance measurement and provides a distance measurement scheme, in which both parts of the two-way asynchronous communication distance measurement can equally acquire a measurement result.

A time synchronization system comprises a GPS (Global Positioning System) receiver for receiving a time signal from a Global Positioning System (GPS), and outputting a UTC (Universal Time Coordinated) synchronization reference signal synchronizing with UTC and a UTC synchronization absolute time signal, and a time signal distributor for generating a reference time signal synchronizing with UTC from the synchronization reference signal and the absolute time signal, and transmits this reference time signal in distribution to a plurality of distributed control oriented terminal devices. The time synchronization between the plurality of distributed control oriented terminal devices can be thereby taken.

A method for synchronizing symbol timing and frequency of symmetric-identical (SI) Orthogonal Frequency Division Multiplexed signals (OFDM) wherein an SI preamble is used for calculation of the symbol timing and frequency synchronism offset of the OFDM signals out of the samples of the received signals is provided. The SI preamble includes a first sample group and a second sample group, being alternately arrayed several times, in which the first sample group includes a designated number of samples that are arrayed in order of arrival, while the second sample group includes the same number of samples with the first sample group, but in inverse order of arrival. Because distinctive correlation coefficients of the identical samples are very distinctive from each other, it is possible to estimate a starting point of the OFDM symbol more precisely. Using the SI preamble, both symbol synchronism and a fine frequency offset and a coarse frequency offset can be estimated. Moreover, the transmission efficiency and the overall capacity of the OFDM system are greatly improved.

The invention discloses a time synchronization method for multi-subsystem equipment and a subsystem. The method comprises that: correspondence between a clock mode of precision time protocol (PTP) networking to which the equipment is to be added and the clock modes of the subsystems is configured on the multi-subsystem equipment to be added to the PTP networking; PTP initialization parameters are configured on internal ports of the multi-subsystem equipment; each subsystem of the equipment receives the announcement that the equipment is to be added to the PTP networking, determines own clock modes according to the clock mode, carried in the announcement, of the PTP networking to which the equipment is to be added, and simultaneously performs PTP initialization according to the PTP initialization parameters configured on own internal ports, and each internal port starts running PTP functions after the initialization is finished; and each subsystem of the equipment performs PTP message interaction with other equipment in the PTP networking by the ports running the PTP functions, and performs time synchronization according to interacted PTP messages. By the method, high-precision time synchronization can be realized between all the subsystems and an external clock when the multi-subsystem equipment is added to the PTP networking.

The invention belongs to the time synchronization technical field and discloses a distributed network time synchronization method. The method includes following steps that: the difference of the clock of a center node and the clock of terminal nodes is determined; after receiving time synchronization request signals sent by different terminal nodes through different carrier frequencies, the center node captures, tracks and demodulates the request signals by using a local spread spectrum sequence database so as to obtain terminal node serial numbers, request sign information and terminal node clock information contained in the request signals, and center node clock information is compared with the local clock of the center node, time difference is measured; and offset correction is performed on the local clock of the terminal nodes according to the difference of the clock of the center node and the clock of the terminal nodes. Through synchronization, accuracy can reach a level of several hundreds of nanoseconds or even a level of dozens of nanoseconds.

The invention discloses a ground mobile communication network positioning method assisted by a communication broadcast satellite signal, relates to a radio positioning technology and in particular relates to a radio positioning technology which is based on a ground mobile communication network and can be used for enhancing a signal by virtue of a communication broadcast satellite. The method comprises the following steps: forwarding a positioning signal, a time scale and a relevant telegraph text by use of a communication broadcast satellite with a forwarding function, or realizing high-precision time synchronization of the ground mobile communication network and the high-precision positioning and time service of a mobile communication set (comprising a mobile phone) by use of a spread-spectrum signal (comprising a pilot frequency frame) in the communication broadcast signal. The method disclosed by the invention has the characteristics that high-precision time synchronization is realized and three-dimensional space positioning precision is improved without changing or slightly changing the equipment structure of the ground mobile communication network base station, the mobile communication set (comprising a mobile phone) and the like.

The invention discloses a 1588-based time synchronization method and system, and relates to the field of communication. The method comprises the following steps: performing detection processing on a phase difference between a system clock and a circuit clock to obtain the phase difference between the system clock and the circuit clock; under the circuit clock, determining a time difference between a rising edge corresponding to a message header mark of a 1588 message and the rising edge of a current period of the circuit clock; under the system clock, generating a timestamp related to the 1588 message; and compensating the generated timestamp by using the phase difference and the time difference, so that the timestamp is consistent with the circuit clock. The timestamp related to the 1588 message is compensated, so that the compensated timestamp is consistent with the circuit clock, and the purpose of high-precision time synchronization is achieved.

The invention discloses a time synchronization method and a time synchronization device of an optical transport network asynchronous network. When a site in an optical transport network receives a time message transmitted by other sites, a first line card in the site recovers clock frequencies of one or a plurality of clock optical path data units(ODUm), wherein m is positive integers which are less than or equal to k, k is an optical path data unit order, and k is equal to 1, 2, 3 and 4, the service of the first line card uses a local clock to be converted to a data frame format of a back plate, the clock ODUm is sent to a second line card in the site through a cross board; the second line card uses the local clock to receive data frames of the back plate and restore the clock frequency of the clock ODUm, and the local clock or a service restoring clock of an optical path transmitting unit (OTUn) optical port is used to send the whole OTUn, wherein n is the order of the optical path transmitting unit. By adopting the time synchronization method and the time synchronization device of the optical transport network asynchronous network disclosed by the invention, the high-precision time synchronization can be supported under the condition that the present optical transport network OTN is asynchronous.

To track the location of a terminal in an indoor space by using a pseudo GPS signal transmitter, a GPS signal sent from an artificial satellite is received, and a clock signal of the artificial satellite is extracted from the received GPS signal to perform synchronization with the artificial satellite. Once synchronization with the artificial satellite is performed, a pseudo GPS signal is generated, and the transmission time of the pseudo GPS signal is controlled. The GPS signal is sent to the terminal located in the indoor space by a plurality of transmitting antennas based on the controlled transmission time, thereby enabling the terminal located in the indoor space to track its location.

The invention discloses an accurate synchronization system with combination of a GPS and a constant-temperature crystal. The accurate synchronization system comprises a GPS receiving module, a frequency calibration and correction circuit, a constant temperature crystal oscillator and a synchronization trigger signal generating circuit, wherein the GPS receiving module is used for receiving a time signal of a positioning satellite so as to output a pulse per second signal (PPS) for accurate synchronization; the constant-temperature crystal oscillator is used for generating a stable frequency output signal; the frequency calibration and correction circuit calibrates and corrects the output frequency of the constant-temperature crystal oscillator by using the PPS; and when the GPS works normally, the synchronization trigger signal generating circuit generates an accurate synchronization trigger signal by using the PPS, and when the GPS works abnormally, the synchronization trigger signal generating circuit generates the accurate synchronization trigger signal by using the corrected output frequency of the constant-temperature crystal oscillator. Therefore, the combination synchronization system can work normally under any environment condition.

The invention discloses a vehicle-mounted ECU high-precision time synchronization method and device. The method comprises the following steps: receiving PPS signals periodically generated and transmitted by a GPS module through a controller chip, switching from a current working state to an interruption state, recording chip time during interruption as first time, receiving a serial port message transmitted by the GPS module again, recording the time when the serial port message is received as second time, and when a time difference between the second time and the first time is within a preset period, analyzing an UTC timestamp from the serial port message, and taking the UTC timestamp as an absolute timestamp corresponding to the chip time. The time of the controller chip is calibrated periodically by utilizing the UTC timestamp, high-precision time synchronization does not depend on a network protocol, the time synchronization of the controller chip in multiple ECUs can be realized by only one GPS module, and the time synchronization method can be deployed in equipment without a network interface or without supporting the network protocol.

The present invention provides a repeater one-station-emitting and multiple-station-receiving secondary planet track detecting method which relates to deep-space tracking technique. Wherein only one ground track detecting station capable of receiving and emitting signals are provided, and other ground track detecting stations are receiving stations. In wartime, emitting station can change according to needs, even emitting in movement without losing precision, to ensure the concealment of whole system, avoid the track detecting station is discovered by enemy efficiently, and enhance the anti-destruction capability and anti-jamming capability of whole system.

The invention relates to a time synchronization method based on a troposcatter channel. The time synchronization method based on a troposcatter channel transmits a time comparison signal to the troposcatter channel, and includes the following steps: establishing a scatter link; sending a time comparison signal generated by a master station atomic clock to a pulse gate, obtaining a video signal bymultiplying a pulse signal which is obtained through processing by the pulse gate by a sine wave, and sending out the obtained video signal through a signal transmitter; sending a time comparison signal to the time interval counter from a slave station atomic clock, and starting timing by the time interval counter; after a signal receiver receives the time comparison signal of the master station,sending the time comparison signal to the time interval counter through a low noise amplifier, a band pass filter, an automatic gain control module and a broadband matching filter, and stopping timingand sending the counted value to a time synchronization data processing unit after the time interval counter receives the time comparison signal of the master station; and calculating the clock difference between the master station and the slave station by the time synchronization data processing unit, determining whether the two station is synchronous in time, and if not, then performing calibration. The time synchronization method based on a troposcatter channel has the characteristics of being autonomous, rapid and over-the-horizon.

The invention provides a method and a system for realizing time synchronization of a vehicle-mounted system based on an IPC mechanism, and a vehicle-mounted central processing unit runs an Ethernet time synchronization protocol gPTP and serves as a master clock to realize high-precision time synchronization of an edge gateway; the edge gateway receives an Ethernet time synchronization message, and operates an Ethernet time synchronization protocol gPTP on an MPU unit to serve as a slave clock to complete time synchronization with the central processing unit; and the MPU unit sends a local synchronized clock to the MCU unit through the IPC mechanism, generates an edge gateway global time reference through a clock synchronization management module of the MCU unit, and performs time synchronization with other ECUs or sensor nodes in a vehicle-mounted network through a CAN bus, thereby realizing global time synchronization of the vehicle-mounted system. According to the invention, elastic and flexible vehicle-mounted system time synchronization is realized.

The invention discloses a pipeline leakage monitoring device which comprises a power supply module, a data acquisition module, a communication module and an embedded control module, wherein the embedded control module is connected with the power supply module, the data acquisition module and the communication module and used for acquiring power supply by virtue of the power supply module, controlling the data acquisition module to acquire pipeline operating state parameters and transmitting the pipeline operating state parameters to a pipeline leakage monitoring system central station by virtue of the communication module.

The embodiment of the invention provides a time synchronization method, a service single board and network equipment. The method comprises the steps that after clock board time synchronization betweenservice single boards, the service single boards obtain CPU time and clock board time of the service single boards according to a preset period and record the CPU time and the clock board time; whenCPU time synchronization between the service single boards is executed, the service single boards obtain current CPU time of the service single boards, and the synchronization time of the CPU is calculated according to the current CPU time and the latest recorded CPU time and clock board time; and the CPU time in the service single board is adjusted to the synchronization time. According to the method, the clock board time between the service single boards needing to realize CPU high-precision time synchronization is synchronized through a high-precision time synchronization protocol, and thenthe CPU time in each service single board is adjusted to the corresponding synchronization time, so that the high-precision time synchronization between the CPUs of the service single boards can be realized.

A method for analyzing technical processes is disclosed, which is characterized in that measuring data of the technical process is generated by at least one decentralized measuring unit, image data associated with a mechanical course of the technical process is produced by at least one decentralized image detection unit, the measuring data stored in the at least one decentralized measuring unit and the image data stored in the at least one image detection unit is provided with a time stamp available to all systems, the measuring and image data are transmitted to a central detection unit where said data is displayed and / or processed in a time-synchronous manner using the time stamp function. Since time stamping is carried out directly in situ, i.e. decentrally in the respective measuring and image detection units, data transmission time required to transmit data to the central detection unit is not critical, so that a time-synchronized display and / or further processing of the measuring and image data can be carried out in the central detection unit with a high degree of accuracy.

The present invention achieves, using simple circuits, timing synchronization among ECUs of an electronic control device which is configured from a driver ECU, a sensor ECU, and an integrated ECU which are connected over a network. This electronic control device is provided with a driver ECU for driving various loads for vehicular control, a sensor ECU for sampling various sensor signals, and an integrated ECU which is connected to the driver ECU and sensor ECU over a network and calculates command values to the various loads in accordance with various sensor data, the electronic control device being characterized in that the driver ECU has timer D for generating internal timing, the sensor ECU has timer S for generating internal timing, and the integrated ECU has timer M serving as a reference for timer D and timer S.

The present invention provides a method and system for realizing the time synchronization of vehicle-mounted systems based on the IPC mechanism. The vehicle-mounted central processing unit runs the Ethernet time synchronization protocol gPTP, acts as a master clock, and realizes high-precision time synchronization for the edge gateway; the edge gateway receives the Ethernet time synchronization message , running the Ethernet time synchronization protocol gPTP on the MPU unit, acting as a slave clock to complete time synchronization with the central processing unit; the MPU unit sends the local synchronized clock to the MCU unit through the IPC mechanism, and through the clock synchronization management module of the MCU unit , generate the global time reference of the edge gateway, and perform time synchronization with other ECUs or sensor nodes in the vehicle network through the CAN bus, and then realize the global time synchronization of the vehicle system. The invention realizes flexible and flexible vehicle system time synchronization.

The invention discloses a time synchronization method and device for an asynchronous network of an optical transmission network. When a station in the optical transmission network receives a time message transmitted by other stations, the first line card in the station recovers one or more clocks The clock frequency of the optical channel data unit (ODUm), where m is a positive integer less than or equal to k, k is the order of the optical channel data unit, k=1, 2, 3, 4, and the service of the first line card uses the local clock Convert to the data frame format of the backplane, and send the clock ODUm to the second line card in the site through the cross-connect board; the second line card uses the local clock to receive the backplane data frame, recovers the clock frequency of the clock ODUm, and uses the optical path transmission unit (OTUn) The local clock or service recovery clock of the optical port sends the entire OTUn, where n is the order of the optical channel transmission unit. The present invention can support high-precision time synchronization under the asynchronous condition of the existing network OTN.

The invention provides a time synchronization method and device, a medium and a program product, and the method comprises the steps: obtaining first ranging information sent by a satellite navigation system and auxiliary information sent by an auxiliary satellite system; the auxiliary information comprises precision orbit data and precision clock error data of the navigation satellite and the auxiliary satellite, second ranging information measured by the auxiliary satellite and first time difference uploaded to the auxiliary satellite by the data center; determining a second time difference between the local time and the navigation time of the ground terminal by using a preset positioning model according to the first distance measurement information and the auxiliary information when positioning calculation is performed on the ground terminal; and correcting the local time according to the first time difference and the second time difference, so that the local time is synchronized with the reference time. The auxiliary satellite system covers the globe, so that the technical problem that time transmission must be performed by depending on a ground communication network in the prior art is solved.

The present disclosure relates to a method and a system for time synchronization based on the 1588 standard and relates to the communications field. The method comprises: obtaining a phase difference between a system clock and a line clock by performing a detection processing on the phase difference between the system clock and the line clock; determining, at the line clock, a time difference between a rising edge corresponding to a message header flag of a 1588 message and a rising edge of a current period of the line clock; generating a 1588-message-related time stamp at the system clock; and compensating the generated time stamp by using the phase difference and the time difference to cause the time stamp to be consistent with the line clock. By compensating the 1588-message-related time stamp, the compensated time stamp is made consistent with the line clock, achieving high-accuracy time synchronization.

The invention discloses a high-precision remote time transmission system and method based on optical fibers. According to the system, a frequency signal transmission unit realizes that master and slave stations send frequency signals mutually through a transmission optical fiber link unit; an optical fiber two-way comparison unit locks any positions of time signals to any positions of the frequency signals, generates 1PPS (pulse per second) time signals at the master and slave stations simultaneously on the basis of the frequency signals and performs optical fiber two-way time comparison on the master and slave stations to acquire the time difference between the 1PPS time signals generated by the master and slave stations respectively; a data transmission unit realizes that the master station transmits time difference data of the 1PPS time signals generated by the master station to the slave stations, calculates clock difference between the master and slave stations and adjusts the time signals of the slave stations according to the clock difference between the master and slave stations. With the adoption of the technical scheme, time signal comparison errors smaller than the single-frequency signal period are effectively controlled, the transmission accuracy of the 1PPS time signals is increased to the sub-picosecond magnitude, and high-precision time synchronization can be performed.