796results about How to "Time synchronization" patented technology

In the invention, at transmitting terminal, the original information treated with carrier modulation is serial-parallel converted into several branch data streams whose amounts are identical with the amounts of antennas; the branch data streams and frequency-domain pilot frequency sequence are commonly mapped into the data position corresponding to the preset frequency-domain pilot frequency pattern; generating each antenna data information which is processed with OFDM modulation and is transmitted by RF transmission. At receiving terminal, each antenna receives the RF signals and generates time-domain output sequence the time-domain output sequence is correlated with the reference sequence to construct synchronous objective function between each pair of antennas so as to implement the synchronization between time and frequency.

The invention discloses a method and a device for synchronizing clocks. The method comprises the following steps of: calculating frequency drift and time migration between a local clock and a master clock; calibrating the local clock by using the frequency drift, and calibrating second pulse signals by using the time migration; and synchronizing the time of work clocks and time stamp modules in physical layer chips by using TOD (time of date) of the calibrated local clock, the calibrated second pulse signals and the rising edge of the calibrated second pulse signals. According to the method and the device, the problem of low synchronization accuracy caused by nondeterminacy of network link delay introduced by the physical layer chips and asymmetry of duplex paths in the prior art is solved, and the time of a plurality of physical layer chips and the master clock is synchronized.

A combined initial alignment system and alignment method for a strapdown inertial navigation system of an underground coal mining machine belong to initial alignment system and alignment method for positioning navigation of underground coal mining machines. The system is composed of a strapdown inertial navigation system installed on the coal mining machine, a wireless sensor network mobile node, an inclination sensor, a geomagnetic field sensor and anchor nodes installed on a hydraulic support. After coarse alignment of the strapdown inertial navigation system, the wireless sensor network is used to detect the location information of the underground coal mining machine, the inclination sensor measures the roll and pitch angle, and the geomagnetic field sensor measures the yaw angle. A pose measurement equation of the coal mining machine is constructed, and the pose measurement equation is combined with an error model after the coarse alignment of the strapdown inertial navigation system to establish a state equation; fusion smoothing is carried out to obtain the accurate location information of the coal mining machine; and the precise alignment of the strapdown inertial navigation system is conducted to complete the initial alignment. The invention realizes precise initial alignment of strapdown inertial navigation combination under the severe closed condition in coal mine, and greatly improves the precision of the integrated positioning under large misalignment angle of the strapdown inertial navigation system of the coal mining machine.

The invention relates to a method for conducting LOFDM system timing and carrier synchronization by utilizing training sequence. The method comprises the following steps: adding training symbols before data symbols for the detection and the synchronization of initial signals; and completing synchronous signal capture through assessing and compensating carrier deviation and timing deviation of signals in system transmission course, and achieving ideal synchronous capture effect. The invention designs the frame format and the training sequence of the LOFDM system and proposes the time and the frequency synchronous method synchronous capture method of the LOFDM system: initial signal detection, rough timing and synchronization and rough decimal multiple frequency offset estimation, accurate timing and synchronization and integral multiple frequency offset estimation, and accurate decimal multiple frequency offset estimation; and accurate time and frequency offset estimation can be obtained under the conditions of low noise-signal ratio and big frequency offset, and when the noise-signal ratio is higher than 2 dB, 100% signal detection can be realized, so as to realize the ideal effect of synchronous capture.

The invention discloses a two-node measuring equipment unrelated quantum key distribution system. Two independent laser devices and a measuring device Charlie are all placed on the same node, namely an Alice end or a Bob end to form the two-node bidirectional transmission quantum key distribution system. According to the system, a two-node structure is adopted, the Faraday conjugated rotation effect is utilized, and the same transmission path is designed; as a result, the problem that an existing three-node measuring equipment unrelated quantum key distribution system is poor in stability due to polarization change, phase drift, non-uniform phase reference systems, time jitter and other factors is effectively solved, the purposes of polarization self-compensation, phase drift self-compensation, calibration-free phase reference systems and easy synchronization are achieved, and an important basis is provided for practical application of the measuring equipment unrelated quantum key distribution system.

The implementation method of the invention provides a method and a device for time synchronization in a passive optical network and the passive optical network. The method and the device belong to the field of network communication. The method comprises the following steps: receiving a synchronous message sent after an optical line terminal OLT maintains time synchronization with a master clock, wherein the synchronous message carries timestamps TMtil determined after the OLT completes the time synchronization; and adjusting a local clock according to the timestamps to enable ONU/ONT to maintain the time synchronization with the OLT, and instructing the ONU/ONT to perform the time synchronization from the clocks after maintaining the time synchronization with the OLT. The implementation method of the invention also provides a device and a system for the time synchronization in the passive optical network, and the system and the method have the advantage of maintaining synchronization of the master clock and a slave clock.

The invention discloses a GPS simulation method and system based on positioning and time service of a Beidou satellite. The GPS simulation system is additionally arranged at the front end of a GPS receiver of an existing base station, a time service result of a Beidou time service receiver is used for taming a local voltage controlled oscillator, and therefore the time of the local voltage controlled oscillator and the time of a Beidou system are synchronous. Under the action of the local voltage controlled oscillator, by using the positioning result and ephemeris parameters of the Beidou time service receiver, GPS simulation signals are synchronously generated for the GPS receiver to complete positioning and time service. In this way, conversion from GPS time service to Beidou time service can be achieved without replacing all devices (including the GPS receiver) in the base station, and therefore the difficulty of replacing the time service conversion devices can be greatly lowered. In addition, the base station after the devices are replaced does not need to depend on an existing GPS system controlled by the USA and uses a Beidou system with the proprietary intellectual property right of China instead, and then the safety and the reliability of communication are effectively promoted.

The invention belongs to the technical field of information retrieval and database structures, and discloses a blockchain-based time distribution and synchronization method, and a data processing system. The method comprises the following steps: a time source issues a time; a consensus node is periodically voted from time nodes, the consensus node packs the time into a blockchain and broadcasts the block in the whole network, and the blockchain is used for recording and transmitting time blocks; the time node receives the time blocks, records the time blocks in an account book and updates a local time; and a terminal device accesses the time node to obtain the time so as to complete time synchronization. The blockchain-based time distribution and synchronization method disclosed by the invention has the advantages of adapting to network topology changes and being able to resist the attacks of malicious nodes. By adoption of a consensus mechanism of a POS, time synchronization can be effectively realized; and time distribution and synchronization are realized with higher efficiency and lower cost. By adoption of the blockchain-based time distribution and synchronization method disclosed by the invention, the problem that the original time distribution mode cannot avoid the attacks of the malicious nodes, and a small number of malicious nodes may affect the operation of the entire system is mainly solved.

The invention discloses a voltage stabilization online monitoring phasor data measurement device and a voltage stabilization online monitoring phasor measurement method. The device comprises a synchronous clock unit, an acquisition unit, an input unit, a dual-port random access memory (RAM) transmission module, a data management unit and an output unit. A precise global positioning system (GPS) synchronous clock signal serves as a reference of a sampling process, so that phasors of each sampling channel are in a determined and uniformed phase relationship; a digital signal processor (DSP) is used for data acquisition and phasor calculation; an embedded real-time operating system and graphical user interface-based ARM9 takes charge of data management and communication, has the characteristics that the processing capacity is high, the real-time is high, the ARM9 is easy to upgrade and the like and improves the reliability, the network communication capacity and the expandability of the measurement device; tripping and closing are executed accurately and reliably according to an upper computer command; the DSP adopts an alpha-beta coordinate system-based phasor measurement algorithm,has the advantages of high computing speed, high suitability and high accuracy, and can accurately compute the information of a voltage/current signal phasor of a power grid; therefore, the problem of spectrum leakage when a signal frequency fluctuates greatly is avoided effectively, and the measurement precision of a non-power frequency input situation and a dynamic process is ensured.

The invention belongs to the field of mapping and navigation, and discloses a pseudolite system and a method based on GNSS(Global Navigation Satellite System) precision time service. The method comprises the following steps: driving a GNSS receiver and a pseudolite signal transmitter by utilizing a homologous crystal oscillator, and solving a clock difference of a local clock of a receiver in realtime by utilizing a precision single point positioning model with coordinate constraint; eliminating a hardware delay between the signal transmitter and the GNSS receiver through a method of calibrating the hardware delay; and broadcasting an obtained clock difference of the local clock to a user in a form of electric files to realize a mathematical synchronization of the local clock and the GNSSsystem time. According to the pseudolite system and the method based on GNSS precision time service, the precision time synchronization of a single pseudolite system and a GNSS system can be realized, and a wired or wireless time synchronization link does not need to be constructed, so that the laying cost and hardware complexity are reduced; and the pseudolite system facilitates the joint positioning calculation with GNSS signals, so that the usability and the reliability of navigation positioning are improved.

The embodiment of the invention provides a command processing method, a command processing device and a command processing system. The method comprises the steps of: receiving multiple voice commands sent by a voice analysis server, wherein the multiple voice commands are generated after source voice commands coming from different voice control devices are analyzed by the voice analysis server; respectively judging if any two voice commands in the multiple voice commands are similar commands, wherein the similar command is a voice command corresponding to the source voice command obtained by using different voice control devices to capture same voice information; and discarding one voice command in two similar voice commands when two voice commands existing in the multiple voice commands are similar commands. The embodiment of the invention further provides a command processing device and a command processing system. With the adoption of the embodiment, the control mistake brought by the repetitive execution of commands is eliminated.

The invention provides a time synchronization method, device and system, and relates to the technical field of the time synchronization. The method executed by the controller comprises the following steps: sending non-instantaneous second pulse to a synchronization sensor, and recording the sending timestamp corresponding to the sending of the non-instantaneous second pulse, wherein the time difference of two adjacent sending timestamps is not a fixed value; sending the time information to the synchronization sensor after sending the non-instantaneous second pulse according to the preset delayduration, thereby enabling the synchronization sensor to calibrate the local time of the synchronization sensor based on the time information, wherein the time information comprises the sending timestamp. Through the time synchronization method provided by the invention, the synchronization sensor and the controller can achieve the time synchronization, and the required software and hardware costis low, and the method can be popularized and applied to the mobile robot and like intelligent equipment.

The invention discloses a synchronization method for orthogonal frequency division multiplexing system, including: the launcher firstly constructs the originated / synchronous sequence that is sent out with OFDM data symbols together. Based on the correlation of CP effective length in OFDM symbols form the receiving end, the correlation result conducts a time domain processing to the correlation sequence energy to get the best synchronization points set after one synchronization. Based on the originated sequence and CP, the departure estimation and departure compensation of fractional part DF several times are processed. During a range of synchronization points set output at once, the long pre-symbol received after the compensation is made time-domain correlation with the symbol to find the second time synchronization point. Then after time-domain of the short pre-symbol and the received pre-sequence is made frequency departure compensation, time-domain-related operations is conduct to get the DF departure estimation of integer times, and departure compensation is conduct.

The invention relates to a short-distance wireless data transmission system with ultra-low power consumption. The system greatly reduces the power consumption of a device while ensuring reliable transmission of data. The system comprises a main device, a plurality of auxiliary devices and a device for dividing a time period of the system into a communication time section and a sleeping time section. In the communication time section, a wireless data transmission module is in a normal working state; in the sleeping time section, microprocessors are in a low power mode; in the low power mode, the microprocessors of the main device and the auxiliary devices enter a sleeping mode, the CPU of the processors stops working, serial port modules of the microprocessors are still in a working state,and the current of the microprocessors is smaller than 550 micron A at the moment; a wireless receiving and transmitting unit stops working in the low power mode; an automatic tracing main device synchronizing device is arranged in each auxiliary device, and the device is used for adjusting the time of the auxiliary devices according to a time frame pair of the main device so as to synchronize with a clock of the main device.

The invention discloses a data collection synchronous method of an electrical railway distance measurement device, which is characterized in that: synchronous data collection is realized through special optical fibers, a distance measurement device of a traction substation is adopted as a main machine, a distance measurement device of AT transformer station and a sectioning station is adopted as an auxiliary machine, and all distance measurement devices are connected with one another through one optical fiber; the length of an optical fiber channel is estimated through the inputted parameter of a distance between every two AT transformer stations, data transmission delay between the devices of the AT transformer stations or between the devices of the AT transformer station and the sectioning station is further calculated according to the length of the optical fiber and the optical speed, a sampling interruption interval time of the auxiliary machines is instantly adjusted according to the calculated fixed data transmission delay, the desynchronizing influence caused by errors such as clock crystal oscillation can be eliminated, and the sampling interruption between the main machine and the auxiliary machine as well as between the auxiliary machine and the auxiliary machine is maintained relatively synchronous.

The invention provides an intelligent watch and a timing system and method of the intelligent watch. The intelligent watch comprises a sensing unit for triggering the timing request signal, and further comprises a mobile terminal which is in short-distance communication with the intelligent watch. The mobile terminal comprises a GPS unit, a communication unit, a man-machine input unit, a standard time and location unit, a time storage unit and a terminal processing unit. The communication unit is used for conducting communication at a timing center to obtain a standard time signal. The terminal processing unit is used for comparing the location information of the GPS unit with the location information of the standard time and location unit so that timing can be achieved at different locations. The invention further provides the timing method of the intelligent watch. The timing system and method are easy to operate, accurate in timing and capable of conducting timing at any location and at different locations.

The invention provides a time synchronization method. The method comprises following steps: receiving standard synchronization time sent by a synchronization clock source through a local area network; obtaining the system time of a computer terminal according to a set time interval; detecting whether the system time and the standard synchronization time are consistent; and if detecting that system time and the standard synchronization time are inconsistent, modifying the system time of the computer terminal according to the standard synchronization time. Moreover, the invention also provides a time synchronization and system. Through the timing service of the standard clock, the time of various communication devices and the computer device on the communication network is unified; the time deviation is limited in a small enough range; the time of the system is ensured to be uniform and synchronous; and the normal operation of a public security emergency command system is ensured.

The inventive embodiment discloses a method, a device and a system for synchronizing time on a main clock side and a slave clock side in a synchronization network, which belong to the communication field and are designed to solve the technical problem in achieving time synchronization of the synchronization network. The method synchronizing time on the slave clock side in the synchronization network comprises the following steps: receiving a synchronous message supported on a first downlink frame; generating an entrance indication pulse according to the received first downlink frame, the entrance indication pulse being fixed with the time delay of fixed-frame bytes in the first downlink frame; collecting a first time on the slave clock side according to the entrance indication pulse; receiving a following message supported on a second downlink frame, the following message carrying a first time for transmitting the synchronous message on the main clock side; and adjusting the local time according to the difference between the first time on the main clock side and the first time on the slave clock side.

The invention discloses a method and system for precisely positioning a mine. The method for precisely positioning the mine comprises the steps that a plurality of positioning base stations and a plurality of marking cards which are used for positioning and are communicated with the positioning base stations through the wireless technology are arranged; distance data are calculated by measuring time spent by signals sent by the positioning base stations flying to the marking cards or the distance data are measured by measuring the time spent by signals sent by the marking cards flying to the positioning base stations; directed wireless antennas are arranged in roadway directions according to the roadway position of the positioning base stations under a coal mine well, the direction information of the positioning cards relative to the positioning base stations is calculated by obtaining antenna information used for communication between the positioning base stations and the positioning cards, and therefore the precise positions of the marking cards are obtained, and precise positioning is achieved. The method for precisely positioning the mine can be implemented under the condition that positioning auxiliary base stations are not required to be deployed, cost is reduced, engineering installation and deployment difficulty are greatly simplified, and time synchronization of the positioning base stations and the marking cards is not needed.

The invention discloses a network data transmission method and device, and is applied to an end-to-end asynchronous transfer network. The method comprises the steps of when the actual operation parameter of a network link from a packet sending end to a packet receiving end is in a preset low-load state and the data volume received by the packet receiving end is smaller than the data volume sent by the packet sending end within a predetermined packet transmission duration, adjusting the service transmission rate of the packet sending end according to a first preset policy; when the service transmission rate of the packet sending end is adjusted to be a minimum transmission rate and the data volume received by the packet receiving end is still smaller than the data volume sent by the packet sending end within the predetermined packet transmission duration, transmitting a TCP message containing a PTP field in the network link from the packet sending end to the packet receiving end to realize the clock synchronization. Based on the network data transmission method and device, the number of lost data packets during the data transmission process of the asynchronous network can be reduced.