825 results about "Time deviation" patented technology

A system and method for time synchronization on a network is provided. According to the system and method for time synchronization, a slave clock device does not continuously receive a time synchronization message periodically transferred from a master clock device and thus does not correct its time upon all such occasions. Rather, the slave clock device requests time information from the master clock device only when the slave clock device needs to correct its time, and receives a time synchronization message transferred from the master clock device and compensates for its time deviation only while the slave clock device is activated, thereby reducing its power consumption and amount of computation.

The invention discloses a method for time synchronous transfer, which comprises the following steps: transmitting a synchronous pulse and transmitting time information of a main device by the main device; receiving the synchronous pulse and recording received time information of a slave device by the slave device; acquiring the transmission time delay of the synchronous pulse; determining the time deviation between the main device and the slave device by the slave device according to the transmitted time information of the main device, the received time information of the slave device and thetransmission time delay; and adjusting a local synchronous clock by the slave device according to the time deviation. The invention also discloses a system and a device for the time synchronous transfer. The method, the system and the device obtain the synchronous errors among devices and compensate the clock according to the synchronous errors so as to reduce the synchronous errors caused by thetransfer time delay of PPS and ensure that the synchronous errors of the cascade connection of a multilevel device are still lower than microsecond level.

The invention requests to protect a time synchronization method applicable to a wireless sensor network and relates to a wireless network communication technology. The time synchronization method comprises the steps: time source equipment generates beacon frames and broadcasts and sends the beacon frames periodically; non-time source equipment obtains time stamps in the transmitting and receiving process of the beacon frames, obtains frequency deviation and time deviation of an equipment clock and a time source equipment clock according to calculation of a plurality of collected time stamps, compensates a local clock and realizes synchronization with a time source; and time synchronization is carried out step by step, and finally the time synchronization of the whole network is realized. Considering the application environment of the equipment and different requirements for time synchronization, a multi-stage and multilevel synchronization mechanism for combining broadcast synchronization, matching synchronization and monitoring synchronization is adopted. The non-time source equipment can apply synchronization of time synchronization command frames according to different requirements, the equipment without applying the time synchronization command frames can monitor and receive the time synchronization command frames similarly and finish synchronization, so that the whole communication overhead and energy consumption of the network are reduced and the normal operation of the network is guaranteed.

The invention discloses a visual real-time deviation rectifying system for a robot. The robot comprises a robot body (4) and an end tool (5) connected to the tail end of the robot body. The system comprises a visual module (3) and a robot controller (2), wherein the visual module (3) is electrically connected with the robot controller (2), and is used for acquiring target image information in real time, processing the acquired target image information so as to obtain position deviation information between the end tool (5) and a target, and sending the position deviation information to the robot controller (2); and the robot controller (2) is electrically connected with the robot body (4), and is used for generating a real-time servo command for controlling the end tool (5) according to the position deviation information from the visual module (3), and sending the servo command to the robot body (4) in real time so as to perform real-time deviation rectifying for the end tool (5).

The invention discloses a method for synchronizing frequency and time of a passive optical network. The method comprises the following steps: an optical line terminal periodically transmits a protocol message with a time stamp to an optical network unit, dynamically measures range information used for maintaining the passive optical network, and acquires time deviation between the optical line terminal and the optical network unit in real time; real-time and dynamic compensation for the time deviation is carried out on the optical network unit, so that the frequency and the time of the optical network unit is synchronized to the optical line terminal. As the range information of the passive optical network is utilized, IEEE1588 protocol is combined, synchronous transfer of time and frequency between devices on the passive optical network can be realized so as to ensure that the optical network unit is accurately synchronized to the optical light terminal on frequency and time, and each optical network unit has the same frequency and time.

The present invention proposes information processing method and device using time domain pilot sequence in OFDM system. The time domain pilot sequence is filled in the initial part of protecting interval of OFDM sign, and rest part of the protecting interval is filled with the circular prefix of OFDM sign, with FFT block being following the circular prefix. Or, the time domain pilot sequence is filled into the whole protecting interval of each OFDM sign, and FFT block follows the protecting interval. The time domain pilot sequence has self-correlation or periodical self-correlation characteristic, equal amplitude or nearly equal amplitude spectrum characteristic, and length of second power. For sake of system design and according to the features of TP sequence, the present invention proposes some transceiving system, time deviation estimation, carrier deviation estimation and channel estimation method and device based on TP sequence characteristic and OFDM sign structure characteristic.

The invention discloses a time synchronization method and a time synchronization system for synchronous messages of IEEE1588 master-slave clocks of an intelligent transformer substation. The method comprises the following steps of: establishing a master clock synchronous message, and sending the timestamp t1 of the sending moment of the message to the clock in a broadcasting manner; recording a receiving moment t2 of the master clock synchronous message; recording an absolute receiving moment TT2 when the master clock synchronous message is received by a slave clock; establishing a slave clock responding message, sending the slave clock responding message to the master clock in a peer-to-peer manner, and recording the timestamp t3 of the sending moment of the message; recording an absolute sending moment TT3 when the slave clock sends the clock responding message; recording an acquiring moment t4 when the master clock acquires the message; calculating a time deviation, and calculating asymmetry errors according to the timestamp t1, the absolute receiving moment TT2, the absolute sending moment TT3 and the acquiring moment t4; and carrying out time correction on the slave clock by the time deviation and the asymmetry errors. According to the time synchronization method and the time synchronization system for synchronous messages of IEEE1588 master-slave clocks of the intelligent transformer substation, the influences of the asymmetry errors can be eliminated, and the time synchronization precision of the master-slave clocks is improved.

The invention relates to a vehicle intersection collision early warning method. Firstly, the position, direction, track radius, speed and acceleration information of a local vehicle and a target vehicle is collected; the driving trajectories and the collision point of the local vehicle and the target vehicle are calculated according to the position, direction and track radius information, and a collision area is calculated according to the collision point; whether the time from driving into the area to driving out of the collision area of the local vehicle and the time from driving into the collision area to driving out of the collision area of the target vehicle are overlapped or not is judged, when the two times are overlapped, the time T needed by the driving into the collision area of the local vehicle with a current speed and acceleration is calculated, and if the time T is smaller than a set value, the early warning result of alarm is executed. According to the scheme, the problems that a collision position is not accurate, the estimated time deviation of arriving an intersection is large and a lot of wrong alarms exist in the prior art are solved.

The invention discloses a multi-core system time synchronization method and a system thereof; the time synchronization method comprises the following steps: A, establishing at least a clock synchronization domain, and distributing the cores respectively into each lock synchronization domain; B, selecting the core with the minimum load as the master clock synchronization source in each clock synchronous domain, and taking the clock synchronization domain having the master clock synchronization source with the minimum load among all the master clock synchronization sources as the master clock synchronization domain, and taking the other clock synchronization domains as the slave clock synchronization domains; C, after the master clock synchronization domain sends synchronization error detection information to each slave clock synchronization domain, calculating the time deviation value between each slave clock synchronization domain and the master clock synchronization domain; D, when the time deviation value is greater than the permitted deviation value, the master clock synchronization domain calculates the time adjustment quantity of each slave clock synchronization domain and releases the time adjustment quantity to each slave clock synchronization domain, then each slave clock synchronization domain makes adjustment based on the corresponding time adjustment quantity. The invention effectively solves the time synchronization problem of the multi-core system.

The invention provides a precise time synchronization method for an industrial wireless network, relating to the industrial wireless network communication technology. Aiming at the characteristics of the industrial wireless network, such as limited energy supply, dynamic and variable network environment, the openness of the wireless network media, and the like, the invention provides a unique precise time synchronization method, wherein, a layering and grading synchronization strategy is adopted to divide the industrial wireless network according to a hierarchical structure; an MAC layer of a parent device generates beacon frames, sends the beacon frames periodically, obtains a time stamp in the processes of sending and receiving beacon frames, obtains the frequency deviation and time deviation of the equipment clock and the universal time clock by fitting the time stamps sent and received in most recently N times, compensates the local clock, realizes the time clock synchronization of a child device and the parent device; time synchronization is carried out in a grade-wise manner and finally the time synchronization of the whole network is realized. On the premise of meeting the performance requirements on the industrial wireless network, the precise time synchronization method of the invention can ensure that the whole network runs within a uniform time scale and guarantee the normal operation of the system.

A servo driver synchronized method based on Ether CAT real-time Ethernet comprises the steps as follows: a slave station link layer control module requests a synchronous interruption to an application layer control module while a distribution clock is triggered; the application layer control module calculates interrupt response time delay delta t1 while entering into the synchronous interruption every time, calculates Tset = TOffset + (Tc-delta t1) while entering into the synchronous interruption for the first time, wherein Tset represents next time of initiating servo interruption after the application layer control module receives a synchronous interruption request for the first time, and TOffset represents time deviation between the next time of initiating servo interruption and time of receiving the synchronous interruption request after the application layer control module receives the synchronous interruption request, and the application layer control module adjusts timing cycle of a servo program which enters into the synchronous interruption for the first time and recovering the timing cycle of other servo programs to normal in a first communication period. The servo driver synchronized method of the invention avoids the conflicts between data updating and a servo application program, and synchronously updates and executes servo control data.

The invention discloses a method of automatic exposure, which comprises the steps of: A. calculating a target exposure value and a current exposure value according to the relation between the brightness value and the exposure value of an image in linear data after initial exposure is carried out and image data is extracted; B. determining the exposure value difference according to the target exposure value and the current exposure value and calculating exposure time deviation value and brightness gain deviation value according to the exposure value difference; C. adjusting an exposure image to new exposure time and new brightness gain and judging whether the difference between the brightness value of the image and a target brightness value under the new exposure time and the new brightness gain meets the condition according to the exposure time deviation value and the brightness gain deviation value, if not, continuing the calculating in the step A until the difference between the brightness value of the image and the target brightness value meets the condition. Meanwhile, the invention also discloses a device of automatic exposure. The embodiment of the invention adopts the linear image data for treatment, which results in the reduction of the calculation amount of the automatic exposure.

An aircraft system includes a deviation module and a visual display. The deviation module is configured to receive a flight plan with a flight segment to a waypoint, the flight plan including a lateral profile, a vertical profile, and a time profile, the time profile including a predetermined time of arrival associated with the waypoint, receive a current lateral position and a current altitude, estimate an estimated time of arrival associated with the waypoint, compare the current lateral position to the lateral profile to generate lateral deviation, compare the current altitude to the vertical profile to generate vertical deviation, and compare the predetermined time of arrival to the estimated time of arrival to generate time deviation. The visual display is coupled to the deviation module and configured to display deviation symbology representing the lateral deviation, the vertical deviation, and the time deviation.

The invention discloses a realization method of a precision synchronous clock and aims at providing a transmission method of a precision synchronous clock in a measuring and automatic system based on an industrial Ethernet. The essential points of the technical scheme of the invention are that the realizing method comprises a frequency and deviation adjusting algorithm based on a fuzzy PID (Proportion Integration Differentiation), a quick internal clock synchronous algorithm, a real-time synchronous check method and a real-time clock frequency and time deviation adjusting algorithm. The invention has the following applications that the method can be used for realizing quick switch of the clock, can be applied to a high-reliability redundant clock source system and can finish the switch of the clock in ten seconds; the transmission precision of a single-stage clock can reach 50ns level; and since the algorithm can be used for realizing the quick switch of the clock, the algorithm is also applied to a high-reliability clock synchronous system under a redundant loop net and the clock HOLDOVER function on terminal equipment is degraded. The invention achieves the functions of software for receiving and transmitting a precision synchronous clock protocol message and adjusting and calibrating a system clock.

The invention relates to technologies for industrial wireless networks, in particular to a method for precisely synchronizing time of an industrial wireless network on the basis of prediction and compensation. The method includes constructing the factory-automation-oriented industrial wireless network into a star network on the basis of an IEEE (institute of electrical and electronics engineers) 802.11 single-hop basic service set (BBS) structure; setting a master clock and slave clocks according to types and functions of nodes in the industrial wireless network; enabling a master clock side and slave clock sides to interact with one another via two-way timestamp information and computing a time deviation value of a current synchronizing cycle; predicting a time deviation value of a next synchronizing cycle by the aid of the time deviation value of the current synchronizing cycle; compensating clock drift by the aid of the predicted time deviation value of the next synchronizing cycle and correcting the clocks. The method has the advantages that the method is implemented on the premise that application requirements of factory automation are sufficiently considered, so that high time synchronization precision can be realized by the aid of few wireless communication resources, and purposes of high precision, high efficiency, low expenditure and easiness in implementation can be achieved.

The invention discloses an E1 link-based bidirectional time-frequency synchronous transmission method and a master-slave device, and relates to communication technology. The method comprises the following steps that: A, a master station transmits a time synchronous frame to a slave station, records a synchronous frame packet transmitting time stamp T1 and inserts the time stamp T1 into the synchronous frame; B, the slave station receives the synchronous frame from the master station, records a packet receiving time stamp T2 and acquires the time stamp T1 from the synchronous frame; C, the slave station transmits a time delay request frame to the master station and records the time stamp T3 for transmitting the time delay request frame; D, the master station receives the time delay request frame transmitted by the slave station and records the packet receiving time stamp T4, and the master station transmits the time stamp T4 to the slave station; and E, the slave station acquires the time stamp T4, calculates line loop time delay D, master-slave time deviation and frequency deviation according to the acquired time stamps T1 to T4 so as to adjust local time and clock frequency, wherein information in each step is encapsulated to be in an E1 frame format. The method and the device have the advantages of no need of protocol conversion or cache and low expenditure, so data transmitting and receiving time delay jitter can be greatly reduced.

The invention relates to a method for improving the clock synchronization precision in a distributed network system. At present, the synchronized precision is relatively lower. Aiming at uncertainty and large disturbance, the invention only makes adjustment when the time offset between a local slave clock and a master clock is less than or equal to the offset value set through a register by the user; if the adjacent twice time offset is still more than the offset value, the invention adjusts the time of the local slave clock according to the time offset value. As the speed of a clock crystal oscillator is deviated, the time interval at which the local slave clock continuously twice sends sync synchronous messages to the master clock and the time interval at which the local slave clock continuously twice receives the sync synchronous messages from the master clock are compared, and then the difference between the two time intervals is evenly distributed within the synchronization interval. The method of the invention solves the problem of the decreasing of the clock synchronization precision to ensure the clock synchronization precision to reach microsecond level, through a filtering algorithm and the even adjustment of the offset of the crystal oscillator of the slave and the master clocks within the synchronization interval.

The invention relates to a contact network key position dynamic offset detection method and a device thereof. A detection identification is arranged on objects at the key position of the contact network to be detected such as contact line of the section, carrier cable, dropper and upright of the detected contact network, an online CCD detection device is arranged on the upright of the contact network, a CCD camera acquires video image of the contact network, the detected displacement and quantity of motion are stored and amplitude, angle of twist and corresponding time course curve are drawn, and the online CCD detection device transmits the data to an upper machine room data center by virtue of a wireless communication module. The method and device of the invention are non contact and self-calibration, practicability is strong, and synchronous monitoring is carried out, so as to obtain data and image; amplitude, frequency, angle of twist and corresponding time course curve are recorded in real time and are used for analyzing influence of the stability of the contact network in high wind environment or under the action of other factors, and travelling is guided according to the real-time deviation state of the contact network.

The embodiment of the invention provides a method and device for monitoring Ethernet clock synchronization. In the method, a slave clock device returns a delay request message to a master clock device, and the delay request message carries link delay information between the master clock device and the slave clock device of a last time hack cycle, determined by the slave clock device, so that the master clock device is enabled to determine a time deviation between the master clock device and the slave clock device and according to whether the time deviation is smaller than a set time deviation threshold, whether to send alarm information is determined. Because in the method, the slave clock device returns the determined link delay information between the slave clock device and the master clock device to the master clock device from the master clock device so that the master clock device is enabled to determine a time hack condition of the slave clock device so as to achieve an objective of monitoring of the slave clock device and thus precision demands of time synchronization are ensured and loss caused by inaccuracy of time hack is reduced.

A time synchronization method and system for a multi-core system are provided. The time synchronization method comprises: establishing at least one clock synchronization domain, and respectively allocating each core to each clock synchronization domain; selecting a core with a lowest load in each clock synchronization domain as a master clock synchronization source in the clock synchronization domain, and selecting the clock synchronization domain having the master clock synchronization source with a lowest load as a master clock synchronization domain, while other clock synchronization domains as slave clock synchronization domains; the master clock synchronization domain sending a synchronization deviation detection message to each slave clock synchronization domain, and calculating a time deviation value; when the time deviation value is greater than a permitted deviation value, the master clock synchronization domain calculating a time adjustment quantity and releasing to each slave clock synchronization domain, making adjustment based on its time adjustment quantity.

A multicarrier receiver that receives N carrier frequencies therein comprises N A / D converters each of which analog-digital converts a receive signal at a sample rate fs for each carrier, N quadrature detectors which receive outputs sent from the N A / D converters therein and digitally quadrature-detect the outputs, respectively, 2N LPFs which allow only desire bands of outputs of the N quadrature detectors to pass therethrough, and N delay time correcting means each of which corrects a processing delay time deviation for each carrier inside the multicarrier receiver in a time unit of less than 1 / fs using a fractional delay filter. The delay time correcting means has, for example, an M-stage shift register which operates at fs and generates a delay of M / fs, and a fractional delay filter which operates at fs and includes an even number of tap coefficients and which generates a delay different from M / fs by 0.5 / fs.

The invention discloses a method for optimizing the time synchronous correction and a device thereof, which are applied to a digital communication network. The method comprises the following steps: a synchronous protocol module acquires the current time offset value by transmitting synchronization messages via a main side and a secondary side; a judgment module compares that the symbol of the current time offset value and the symbol of the time offset value of the previous synchronization are both positive or both negative; if yes, the judgment module makes a decision that the clock slave is in the positive offset or negative offset relative to the clock master, and correspondingly determines that the follow-up correction is the negative correction or the positive correction, that is, a follow-up correction module decreases a preset interval adjustment step size value from or adds a preset interval adjustment step size value to the synchronous correction at each time of follow-up correction. The method and the device for optimizing the time synchronous correction process the time offset value and take different synchronous correction plans according to the processing result, effectively improve the synchronization precision without changing the synchronization frequency or the interval time, and have strong anti-interference capability and good versatility.

The invention discloses a bus behind-schedule recovering method based on arrival time predication with a time window. The method provides a behind-schedule recovering concept on the basis of arrival time predication of a bus. The specific method comprises the following steps of: firstly, predicating arrival time of the bus by using Kalman filtering; secondly, taking a predication result as the basis and giving out a dispatching time judging time window; and finally, providing the behind-schedule recovering concept and introducing a time deviation coefficient; taking a corresponding speed of a critical time deviation coefficient and a maximum allowable speed as restrictions to establish a behind-schedule recovering model, so as to provide a referred speed of road segment driving to a bus driver and a dispatching center to avoid possible behind-schedule or recover normal operation as soon as possible.

The invention relates to a precision and stability monitor method for a clock, comprising: a clock supporting NTP standard is directly set to be a NTP server mode, and the clock not supporting NTP standard acquiring time by a synchronous monitor device; a dispatching center sets a NTP client-side which is connected with each NTP server terminal by a NTP communication mode; when the NTP client-side inquires the time of the monitored clock, each NTP server terminal transmits time to the NTP client-side in real time by a NTP protocol; the NTP client-side is compared with a setting optimum reference time resource to obtain a time difference for evaluating precision and stability of the monitored clock equipment. The invention sets a time monitor network by a NTP standard, and the NTP client-side compares the monitor clock time with the optimum reference clock resource time to be judged whether consistent for evaluating precision and stability of each monitored clock equipment. The invention is convenient in use and uniform management, which saves the cost.

The embodiment of the invention discloses an interference measurement method and apparatus, and a timing deviation measurement method. The method comprises the following steps: a first communication device obtains first transmission configuration information, wherein if a second communication device is a first base station, the first communication device is a second base station or user equipmentUE connected to a cell formed by the second base station, and if the second communication device is first UE, the first communication device is second UE or a neighboring base station of the base station to which the first UE is connected; and performing measurement on a first reference signal according to the first transmission configuration information to form a first measurement result, whereinthe first measurement result is used for cross-link interference coordination.

An electronic musical apparatus for training to play the apparatus in correct timing comprises a play timing notifying device which notifies reference time points in a music progression for operating the apparatus to play music, an operation detecting device for detecting each of player's operations on the apparatus as a player operates the apparatus with reference to the reference time points, a time deviation detecting device for detecting a time deviation of each of the player's operations from corresponding one of the reference time points, a tolerance range setting device for setting a tolerance range with respect to each of the reference time point by taking into consideration a plurality of the past detected time deviations, the tolerance range being for evaluating whether a detected time deviation falls within the tolerance range or not, and a tone generation control device which controls generation of tones for the player's operations differently according to whether each detected time deviation falls within the tolerance range or not. The tolerance range is set automatically based on the plurality of past detected time deviations. The tolerance range is divided into an advance margin and a delay margin about the reference time point, which two margins are preferably set separately. The detected time deviations are shown on a display screen in reference to the reference time points.

The invention discloses a switching method and a switching system for streaming media playing. The method includes: downloading multiple pieces of code rate information and resource address information corresponding to code rates from a streaming media server and storing the information; creating multiple threads corresponding to the code rate information; downloading and analyzing index information of multiple code rate resources; respectively refreshing serial numbers of the corresponding code rate resource index information by the threads during streaming media playing; if the serial numbers refreshed by the threads are not uniform, acquiring basic clocks of the code rate resources according to fragments of the code rate resources, and switching to corresponding positions for playing according to the basic clocks of the different code rate resources, corresponding serial number deviations and time deviations of the different code rates. The system comprises a Source module, an analysis module, a decoder and an output module. By the switching method and the switching system, the problems of audio / video non-synchronism and image discontinuity during adaptive dynamic switching of network streaming media playing are solved. The switching method and the switching system can be widely applied to various types of streaming media playing.